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Transcript
Summer 2014 NIDDK Medical Student Research Symposium Student Life Center Vanderbilt University Nashville, TN August 6 and 7, 2014 Funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Table of Contents
Description of the Program ......................................................................................................... 2
Agenda .................................................................................................................................. 3 - 4
Students Participating in the Program ................................................................................... 5 - 9
Medical Schools of Student Participants .................................................................................. 10
Visiting Professors for Research Symposium .................................................................... 11 - 13
Vanderbilt Faculty Participating In Moderating the Poster Sessions and Lunches ……………14
NIDDK-Funded Diabetes Centers ............................................................................................ 15
Supporting Training Grants for Diabetes Program .................................................................... 16
Advisory Panel for Program ...................................................................................................... 17
Abstracts from Students ......................................................................................................... 18+
1
Description of the Programs Supporting
The NIDDK Medical Student Research Symposium
The National Institutes of Health (NIH) through the National Institute of Diabetes and Digestive
and Kidney Diseases (NIDDK) supports programs to encourage physicians to enter careers involving
research. These programs offer first- and second-year medical students the opportunity to conduct
mentored research. The research opportunities range from basic laboratory studies to clinical studies in
humans. Students also participate in a core curriculum of seminars on research approaches as well as
a variety of clinical and research topics in diabetes and kidney disease. These programs help students
gain an improved understanding of career opportunities in biomedical research.
At the conclusion of the summer, each student presents his/her work at the NIDDK Medical Student
Research Symposium, which provides a venue for the students to meet, share their research, and to
learn about career pathways and opportunities in NIDDK-related professions. The Vanderbilt Diabetes
Center and the NIDDK-funded, Vanderbilt Diabetes Research and Training Center are hosting the
sixth annual NIDDK Medical Student Research Symposium on August 6 and 7, 2014 in Nashville,
Tennessee.
For the summer of 2014, the 126 students from 69 medical schools who are attending the NIDDK
Medical Student Research Symposium were supported by the following programs:
• NIDDK Medical Student Research Program in Diabetes in which students conducted research at
one of 15 NIDDK-funded Diabetes Research Centers
• Vanderbilt Student Research and Training Program in which students conducted research in
diabetes, obesity, renal disease, or GI disease at Vanderbilt University
• Diabetic Complications Consortium in which students conducted research on complications of
diabetes at a NIDDK-funded Diabetes Research Center
• Vanderbilt Center for Kidney Disease in which students conducted research in renal disease at
Vanderbilt University
• Summer Program in Obesity, Diabetes and Nutrition Related Research Training in which
students conducted research at the University of Maryland
2
Symposium Agenda for
NIDDK Medical Student Research Program Symposium
Student Life Center, Vanderbilt University
August 6 – 7, 2014
Tuesday, August 5
7:00 pm
Opening reception in Centennial Ballroom, Holiday Inn Vanderbilt
Wednesday, August 6
8 – 8:45 am
Poster set up in the Student Life Center
9:00
Welcome and introduction
Alvin C. Powers, MD
Joe C. Davis Chair in Biomedical Science
Professor of Medicine and Molecular Physiology & Biophysics
Chief, Division of Diabetes, Endocrinology & Metabolism
Director, Vanderbilt Diabetes Center
Vanderbilt University Medical Center
9:15 – 10:00
Presentation – Ballroom C
Richard G. Kibbey, MD, PhD
Associate Professor of Medicine, Division of Endocrinology and
of Cellular & Molecular Physiology
Yale School of Medicine
10:00 – 11:30
Poster session 1 (moderated)
11:45 – 1:00
Lunch with visiting professors in small groups
1:00 – 1:45
Presentation – Ballroom C
Andrea L. Cherrington, MD
Associate Professor, Department of Medicine, Division of Preventative Medicine
University of Alabama at Birmingham
1:45 – 3:15
1:45 – 2:30
Poster Session A (open)
Odd numbered posters present
Even numbered posters visit
Even numbered posters present
Odd numbered posters visit
2:30 – 3:15
3:15
Reassemble for Program Information – Ballroom C
3:30 - 5:00
Poster Session 2 (moderated)
5:00
Reception
3
Thursday, August 7
9:00 am
Welcome – Ballroom C
Mark de Caestecker, MB, BS, PhD
Associate Professor of Surgery, Medicine, Division of Nephrology and Cell & Developmental
Biology
Vanderbilt University Medical Center
9:05 – 10:15
Poster Session B (open)
Even numbered posters present
Odd number posters visit
10:15 – 11:00
Approaches to Residency Selection and Application
John A. McPherson, MD, FACC, FACP
Associate Professor of Medicine
Vice-Chair for Education, Department of Medicine
Director, Internal Medicine Residency Program
Vanderbilt University Medical Center
and
Rebecca Swan, MD
Director, Pediatric Residency Program
Associate Professor of Pediatrics, Division of General Pediatrics
Assistant Dean of Graduate Medical Education
Vanderbilt University Medical Center
11:00 – 12:30
Poster Session 3 (moderated)
12:30 – 1:15
Lunch with visiting professors in small groups
1:15 – 2:15
Poster Session C (open)
Odd numbered posters present
Even number posters visit
2:30 – 3:15
Presentation – Ballroom C
Art Castle, PhD
Director, Metabolomics and Informatics Program, Division of Diabetes, Endocrinology &
Metabolic Diseases
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
and
Alvin C. Powers, MD
Joe C. Davis Chair in Biomedical Science
Professor of Medicine and Molecular Physiology & Biophysics
Chief, Division of Diabetes, Endocrinology & Metabolism
Director, Vanderbilt Diabetes Center
Vanderbilt University Medical Center
3:15
Concluding remarks
6:15
6:30
9:00
Meet the bus in front of the Holiday Inn Vanderbilt for transport to restaurant
Dinner in downtown Nashville
Approximate end to dinner; students on own for return to hotel
Friday, August 8
Students depart on own
4
Participants 2014
Abburi, Nandini, S
Altshuler, Courtney
Amezquita, Joel
Asfaw, Elizabeth, K
Beardsley, Ryan, D
Beltre, Melba A
Bian, Rachel R
Binns, Thomas (Chad)
Bloom, Benjamin, A
Brooksbank, Jeremy
Buendia, Matthew A
Butler, Erin
Cai, Steven
Card, Casey, E
Choudhury, Natasha
Chun, Hyun, B
Clancey-Rivera, Marie G.
Cole, Heather
Contreras, Ignacio J
Couzens, Erica, C
Cross, Benjamin R
Das, Anjali
David, Sthuthi
Deshpande, Sagar, S
Diao, Xavier
Downes, Laura
Estrada, Kathleen, L
Abst #
10
69
86
38
81
101
122
14
68
22
66
2
44
40
25
80
91
9
70
39
52
59
20
125
1
35
6
5
University of Kentucky
Michigan State University
University of Toledo
University of Southern California
University of California - Los Angeles
University of California - Los Angeles
University of Illinois - Champaign-Urbana
New York Medical College
University of Michigan
University of Arkansas
University of Maryland
University of Tennessee
University of Tennessee
Eastern Virginia Medical School
Rosalind Franklin University
National University of Ireland - Galway
Meharry Medical College
Stony Brook Medicine
Ponce School of Medicine and Health Sciences
University of Tennessee
Columbia University
Loma Linda University
University of Nebraska
Rutgers NJ Medical School - Newark
University of Rochester
University of Michigan
University of Maryland
Medical School
Vanderbilt
U Michigan
U Michigan
Vanderbilt
Yale
Washington U
U Chicago
BADERC
U Michigan
Vanderbilt
JHopkins/U Maryland
Vanderbilt
Vanderbilt
U Maryland
Vanderbilt
Yale
Vanderbilt
UCSD
Yale
Vanderbilt
Columbia
U Washington
UCSD
Vanderbilt
Vanderbilt
U Michigan
U Maryland
Center for Summer
Email address
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
2014 Participants in the
NIDDK Medical Student Research Program in Diabetes and Obesity
Participants 2014
Etiel, Kelsey
Foggia, Megan, J
Fowler, Zachary, G
Fox, Kacie, R
Freeman, Casey
Galletta, Thomas
Gandhi, Shriya
Ghosh, Sujata
Gonsalves, Zenobia, T
González Bouza, Beatriz
Guzman, Herodes, G
Han, Amy Yuh Jung
Harrison, Bradley
Hoover, Elizabeth, A
Ikizler, Halil, O
Jain, Tarun
Jin, Hope, L
Jones, Terrence T
Jose, Charles
Kelly, Emily
Kim, Janice, S
Kim, Jessica
Kissel, Suzanne
Kuhlmann, Paige, K
Landreth, Hannah
Leiva, Orly
Lepard, Morgan
Abst #
124
19
43
30
34
119
112
31
110
5
108
46
73
97
113
76
55
37
85
67
83
26
114
17
53
16
111
6
Loyola University - Chicago
University of Nevada
University of North Dakota
University of Hawai'i
University of Kansas
Northeast Ohio Medical University
University of Illinois - Chicago
Texas A&M Health Science Center
Rosalind Franklin University
University of Puerto Rico
University of North Carolina
Case Western Reserve University
Mercer University
University of Iowa
University of Vermont
Indiana University
New York Medical College
University of Tennessee
University of Nevada
Florida Atlantic University
Washington University
University of Nevada
Indiana University
University of Missouri - Columbia
University of Oklahoma
Boston University
University of Tennessee
Medical School
Vanderbilt
UCLA
Columbia
Joslin
Vanderbilt
Vanderbilt
U Chicago
Vanderbilt
U Washington
Washington U
UCSF
U Pennsylvania
Vanderbilt
Columbia
U Washington
Vanderbilt
Joslin
UAB
Vanderbilt
Vanderbilt
Yale
Vanderbilt
Vanderbilt
Washington U
Vanderbilt
Joslin
UAB
Center for Summer
Email address
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
2014 Participants in the
NIDDK Medical Student Research Program in Diabetes and Obesity
36
50
103
28
107
18
64
45
3
47
102
12
116
24
63
100
4
62
11
87
94
71
48
27
56
74
84
Abst #
7
Leung, Sophie, L
Li, Jennifer
Li, Muyi
Liao, Si (Sherry)
Lindauer, Katherine L.
Linder, Alexandra, N
Liu, Mingchun
Love, Heather R.
Ludi, Nicolas
Lyons, James
Magee, Ronald, R
Marcaccio, Christina, L
Marks, Bianca
Martinez, Jordan A
Matar, Regina, N
Mauch, Scott, C
Mazza, Dayna
Mehregan, Christian, A
Milligan, Ian, L.
Mizera, Megan
Morones, Nohemy
Mottla, Jay, L
Moutos, Christopher, P.
Mulero Morales, Maris
Nevarez, Nicole M.
Nguyen, Kerrie, K
Nguyen, Ngoc, B
Participants 2014
Dartmouth University
Rosalind Franklin University
Medical University of South Carolina
New York Medical College
Michigan State University
Tulane University
University Alabama - Birmingham
Tufts University
University of Tennessee
University Alabama - Birmingham
Brown Uniersity
University of Pennsylvania
Meharry Medical College
Jefferson Medical College
Michigan State University
Michigan State University
University of Maryland
Wayne State University
Saint Louis University
University of Central Florida
Columbia University
Georgetown University
University of Arkansas
Ponce School of Medicine and Health Sciences
University of Michigan
Tulane University
University of Washington
Medical School
BADERC
UCLA
Yale
Vanderbilt
U Chicago
Columbia
UAB
Joslin
Vanderbilt
UAB
JHopkins/U Maryland
U Pennsylvania
Vanderbilt
U Pennsylvania
Columbia
U Michigan
U Maryland
U Michigan
Washington U
Vanderbilt
UCSF
BADERC
JHopkins/U Maryland
Vanderbilt
U Michigan
UCSD
U Washington
Center for Summer
Email address
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
2014 Participants in the
NIDDK Medical Student Research Program in Diabetes and Obesity
Participants 2014
Nigam, Tina
Oelsner, Kathryn
Oelsner, William
Olecki, Elizabeth
Order, Kaitlyn, E
Ortiz Baez, Vivian
Owens, Sarah
Pahouja, Gaurav
Panosian, Jennifer, A
Parris, Donique A
Patel, Feenalie, N
Penchev, Radostin
Popli, Tanav
Prasad, Pooja
Pujare, Deepti, U
Rabbani, Zaheen
Rai, Dilreet
Rai, Puja
Ramirez, Lourdes, G
Ran, Nina, A
Reed, Thomas
Rockas, Mary, Demetra
Roos, Vanessa
Scheidemantle, Brooke
Sharma, Ellora, V.
Sherwood, Pamela, R
Shin, Won Seok
Abst #
7
95
99
72
58
123
42
29
93
77
90
65
75
78
79
92
117
96
109
54
13
98
33
88
15
126
32
8
Michigan State University
Medical University of South Carolina
Medical University of South Carolina
Northeast Ohio Medical University
Georgetown University
San Juan Bautista School of Medicine
University Alabama - Birmingham
Northeast Ohio Medical University
Tufts University
University of Maryland
University of Tennessee
George Washington University
Indiana University
University of Rochester
New York Medical College
University of Louisville
University Missouri - Kansas City
University of Connecticut
University of Central Florida
University of Pennsylvania
George Washington University
University of Michigan
Medical University of South Carolina
Thomas Jefferson Medical College
Northeast Ohio Medical University
Tufts University
Eastern Virginia Medical School
Medical School
U Michigan
Vanderbilt
Vanderbilt
Vanderbilt
BADERC
Vanderbilt
UAB
JHopkins/U Maryland
Joslin
JHopkins/U Maryland
BADERC
Vanderbilt
Vanderbilt
UCSF
UCSF
U Washington
U Washington
Coumbia
Joslin
U Pennsylvania
Vanderbilt
U Michigan
JHopkins/U Maryland
U Chicago
JHopkins/U Maryland
BADERC
Vanderbilt
Center for Summer
Email address
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
2014 Participants in the
NIDDK Medical Student Research Program in Diabetes and Obesity
49
21
51
106
23
61
105
89
115
118
57
60
8
104
121
82
120
41
Abst #
9
Silva, Alejandro, J
Tanaka, Mari
Tarun, Samiksha
Thakur, Sneha
Theprungsirikul, Poy
Vangala, Divya
Venn, April, M.R.
Verlage, Kenneth
Wang, Eileen
Weintraub, Michael
Welch, Andrew, A
Wesson, Emily
Whitlock, Scott M
Xie, Juliana, L
Xu, Cassie
Young, Verona
Zhong, Le
Zhu, Linjue
Participants 2014
Rutgers NJ Medical School - Newark
Georgetown University
Saint Louis University
New York Medical College
Dartmouth University
Marshall University
Dartmouth University
Texas Tech University
Rush Medical College
Rutgers Robert Wood Johnson - Piscataway
Midwestern University - Glendale
University Alabama - Birmingham
Eastern Virginia Medical School
Pennsylvania State University
Indiana University
Stony Brook University
University of Miami
Medical College of Georgia
Medical School
BADERC
Vanderbilt
Washington U
Washington U
Joslin
Joslin
Vanderbilt
Vanderbilt
Vanderbilt
Vanderbilt
U Washington
UAB
JHopkins/U Maryland
Joslin
Vanderbilt
Columbia
Vanderbilt
Vanderbilt
Center for Summer
Email address
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
2014 Participants in the
NIDDK Medical Student Research Program in Diabetes and Obesity
Medical Schools of Students Participating in the
2014 NIDDK Medical Student Research Symposium
Boston University
Brown University
Case Western Reserve University
Columbia University
Dartmouth University
Eastern Virginia Medical School
Florida Atlantic University
George Washington University
Georgetown University
Indiana University
Jefferson Medical College
Loma Linda University
Loyola University - Chicago
Marshall University
Medical College of Georgia
Medical University of South Carolina
Meharry Medical College
Mercer University
Michigan State University
Midwestern University - Glendale
National University of Ireland - Galway
New York Medical College
Northeast Ohio Medical University
Pennsylvania State University
Ponce School of Medicine
Rosalind Franklin University
Rush Medical College
Rutgers NJ Medical School - Newark
Rutgers Robt Wood Johnson - Piscataway
Saint Louis University
San Juan Bautista School of Medicine
Stony Brook Medicine
Texas A&M Health Science Center
Texas Tech University
Thomas Jefferson Medical College
Tufts University
Tulane University
University Alabama - Birmingham
University Missouri - Kansas City
University of Arkansas
University of California - Los Angeles
University of Central Florida
University of Connecticut
University of Hawai'i
University of Illinois - Champaign-Urbana
University of Illinois - Chicago
University of Iowa
University of Kansas
University of Kentucky
University of Louisville
University of Maryland
University of Miami
University of Michigan
University of Missouri - Columbia
University of Nebraska
University of Nevada
University of North Carolina
University of North Dakota
University of Oklahoma
University of Pennsylvania
University of Puerto Rico
University of Rochester
University of Southern California
University of Tennessee
University of Toledo
University of Vermont
University of Washington
Washington University
Wayne State University
10
Visiting Professors/Faculty for the
NIDDK Medical Student Research Symposium
Art L. Castle, PhD
Program Director
Metabolomics and Informatics
National Institute of Diabetes &
Digestive & Kidney Diseases
National Institutes of Health
6707 Democracy Blvd., Rm 791, MSC
5460
Bethesda, MD 20892-5460
[email protected]
Andrea L. Cherrington, MD
Associate Professor
Division of Preventative Medicine
Department of Medicine
FOT 725
University of Alabama at Birmingham
Birmingham, AL 35294
[email protected]
Richard G. Kibbey, MD
PO Box 208056
Yale School of Medicine
333 Cedar Street
New Haven, CT 06520-8056
Richard.kibbey@yale.
Alvin C. Powers, MD
Joe C. Davis Chair in Biomedical Science
Professor of Medicine, Molecular
Physiology & Biophysics
Director, Vanderbilt Diabetes Research
and Training Center
802 Light Hall
Vanderbilt University Medical Center
2215 Garland Avenue
Nashville, TN 37232-0202
[email protected]
Mark de Caestecker, MB, BS, PhD
Associate Professor of Medicine, Division
of Nephrology, and of Cell &
Developmental Biology and Surgery
S-3223 Medical Center North
Vanderbilt University Medical Center
Nashville, TN 37232-23372
[email protected]
11
Biographies of NIDDK Visiting Professors and Faculty
Art L. Castle, PhD is the Director of the Metabolomics and Informatics Program, Division of
Diabetes, Endocrinology and Metabolic Diseases at the National Institute of
Diabetes and Digestive and Kidney Diseases, National Institutes of Health.
Arthur L. Castle has a PhD in Physiology from University of Texas, Austin. He
did his postdoctoral research training study glucose transporters at NIDDK/NIH
before working as a Manager in Bioinformatics for Gene Logic Inc. His
research experience includes diabetes, metabolism, genomics, bioinformatics,
and computer simulation/modeling. Dr. Castle joined the Division of Diabetes,
Endocrinology and Metabolic Diseases, NIDDK, NIH, DHHS in 2004, where he
is current the program director for fellowships (“F”) awards, institutional training
grants, metabolomics and informatics.
Andrea L. Cherrington, MD, MPH, is an Associate Professor in the Division of Preventive
Medicine at the University of Alabama at Birmingham where she is a clinician
trained in health services research and community-based participatory research
methods. After completing Internal Medicine residency training in 2003, she
attended the University of North Carolina-Chapel Hill as a fellow in the Robert
Wood Johnson Clinical Scholar’s Program (CSP) and obtained an MPH from the
UNC School of Public Health. Following the CSP, she obtained funding for a
third year of fellowship through an NRSA T32 mechanism.
In 2006, Dr. Cherrington returned to Alabama as an Assistant Professor of
Medicine at UAB. She has received funding for her research through pilot grants
from the UAB Minority Health and Research Center, the UAB Clinical Nutrition
Research Center, the UAB Diabetes Research and Training Centers, and the
American Diabetes Association. Her research focuses on developing,
implementing and evaluating community-based interventions to promote weight
loss and improve the outcomes of disadvantaged populations at high risk for developing chronic
disease, specifically diabetes. Additionally, she obtained two career development awards, one through
the Robert Wood Johnson Foundation and the other an internal K12 in Comparative Effectiveness
Research. Both projects focus on use of the Community Health Worker model for the reduction of
diabetes related health disparities. Dr. Cherrington co-directs the Intervention and Translational Core
within the UAB Diabetes Research Center. She is currently involved in several projects that seek to
advance methods of community-based intervention delivery by combining the Community Health
Advisor model with multi-component, technology-assisted support systems comprising health
professionals. In keeping with her research interests, she has a continuity clinic two half days per week
within Cooper Green Health System, the county’s safety net system.
Mark de Caestecker, MB, BS, PhD, received his undergraduate degree from Cambridge
University and medical degree (M.B., B.S.) from The Middlesex Hospital (now
University College) in London, England. After training in internal medicine at
the Middlesex and Charring Cross Hospitals in London, Dr. de Caestecker
trained in Nephrology, obtained his PhD in Medicine at the University of
Manchester, and underwent post-doctoral training on a Wellcome Trust
Clinical Scientist Fellowship at the NIH under the mentorship of Dr. Anita
Roberts. He is currently an Associate Professor in the Division of Nephrology
at Vanderbilt, and conducts NIH funded research on regenerative therapies in
acute and chronic kidney injury, and on hereditary vascular diseases. He
12
currently serves on the Respiratory and Integrative Biology and Translational Research study section.
Dr. de Caestecker is Director of the Vanderbilt-HHMI Certificate Program in Molecular Medicine, and
Director of the Vanderbilt Center for Kidney Disease education program. He has directed the summer
research-training program in kidney disease for the last four years.
Richard G. Kibbey, MD, PhD is an Associate Professor in the Departments of Internal
Medicine Division of Endocrinology and Cellular & Molecular Physiology at
Yale University School of Medicine. He attended Trinity University in San
Antonio where he obtained a degree in Music and a degree in Biochemistry.
Next he completed his M.D. Ph.D. training at UT Southwestern in Dallas in the
laboratories of Drs. Lila Gierasch and Richard Anderson where he studied
NMR structural biology. From there he short-tracked through internal medicine
residency and endocrinology at Yale to later do a postdoctoral fellowship in the
laboratory of Dr. Gerald Shulman. During his fellowship he obtained support
from the Clinical and Scientific Training Award, American Diabetes Association
Junior Faculty Awards, and a NIH K08. Since then he has obtained additional
funds from ADA research grants, NIH R03 and R01 awards, and several
industry-sponsored awards. At Yale he runs an independent research lab
studying the metabolism of diabetes with particular interest in human islet
biology. Here he has identified a novel mitochondrial energy sensing mechanism that regulates glucose
homeostasis and has developed state-of-the-art techniques for measuring intracellular metabolic fluxes.
He is currently working closely with the pharmaceutical industry to translate these findings into new
therapies. As a practicing Endocrinologist he also sees patients in a continuity clinic ½ day per week
and attends on the Endocrine Consult Service as well as General Internal Medicine 1-1.5 months a
year. In addition he teaches medical physiology to first year medical students.
Alvin C. Powers, MD, the Joe C. Davis Chair in Biologic Science and Professor of Medicine,
Molecular Physiology and Biophysics at Vanderbilt University, is the Director
of the Vanderbilt Diabetes Center, the Chief of the Vanderbilt Division of
Diabetes, Endocrinology, and Metabolism, and the Director of the Vanderbilt
Diabetes Research and Training Center, a NIH-funded center that facilities
the diabetes-related research of more than 120 Vanderbilt scientists. He
conducts diabetes-related research that focuses on pancreatic islet biology,
development, function, and transplantation. His research is or has been
supported by the NIH, the VA Research Service, the Juvenile Diabetes
Research Foundation (JDRF), and the American Diabetes Association (ADA).
Dr. Powers is the Director of the Vanderbilt Medical Student Research
Training Program in Diabetes, Endocrinology, and Metabolism and the
Coordinator for the NIDDK Medical Student Research Program in Diabetes.
These two programs enable more than 100 medical students to conduct diabetes-related research
each summer at a NIDDK-supported Diabetes Research Center. Dr. Powers, a physician at Vanderbilt
University Medical Center and the VA Tennessee Valley Healthcare System, is listed by Castle
Connolly Medical Ltd as one of “America’s Top Doctors.” Dr. Powers received his undergraduate
degree from the University of Virginia and his medical degree from the University of Tennessee Center
for the Health Sciences. After training in internal medicine at Duke University Medical Center, Dr.
Powers trained in Endocrinology and Diabetes at the Joslin Diabetes Center, the Massachusetts
General Hospital, and Harvard Medical Schooll.
13
Vanderbilt Faculty Participating
In Moderating the Poster Sessions and Lunches
Nathan Bingham, MD, PhD
Milam A. Brantley, MD, PhD
Jessica Devin, MD
Raymond C. Harris, MD
J. Matthew Luther, MD
James M. May, MD
Owen P. McGuinness, PhD
Daniel J. Moore, MD
Kevin D. Niswender, MD, PhD
Richard M. Peek, MD
William (Bill) E. Russell, MD
Ashley H. Shoemaker, MD
John M. Stafford, MD, PhD
James W. (Tom) Thomas, MD
Melissa F. Wellons, MD
Keith T. Wilson, MD
Lan Wu, MD
14
NIDDK-Sponsored Diabetes Research Centers
Boston Area Diabetes Center
DK057521
Columbia University
DK063608
Johns Hopkins University and University of Maryland
DK079637
Joslin Diabetes Center
DK036836
University of Alabama at Birmingham
DK079626
University of California at San Diego and University of California at Los Angeles
DK063491
University of California at San Francisco
DK063720
University of Chicago
DK020595
University of Michigan
DK020572
University of Pennsylvania
DK019525
University of Washington
DK017047
Vanderbilt University
DK020593
Washington University
DK020579
Yale University
DK045735
15
Training Grants Supporting
2014 NIDDK Medical Student Research Program in Diabetes
Grant Number
T32 DK007770-13
T32 DK007328-35
T32 DK007751-18
T32 DK007260-38
T32 DK007028-40
T32 DK062710-11
T32 DK007494-30
T32 DK007418-34
T32 DK007011-40
T32 DK007245-38
T32 DK007314-34
T32 DK007247-37
T32 DK007061-40
T35 DK007383-35
T32 DK007120-40
PI of Training Grant
Melmed, Shlomo
Gottesman, Max
Radovick, Sally
Blackwell, Thomas Keith
Avruch, Joseph
Allison, David
Witztum, Joseph L
German, Michael
Refetoff, Samuel
Auchus, Richard
Birnbaum, Morris
Schwartz, Michael
May, James
Powers, Alvin
Semenkovich, Clay
Institution
Cedars Sinai Medical Center
Columbia University
Johns Hopkins University
Joslin Diabetes Center
Massachusetts General Hospital
University of Alabama Birmingham
University of California San Diego
University of California San Francisco
University of Chicago
University of Michigan
University of Pennsylvania
University of Washington
Vanderbilt University
Vanderbilt University
Washington University
T32 DK007058-40
Wysolmerski, John
Yale University
Some students were supported by the Diabetic Complications Consortium
U24 DK076169-03
McIndoe, Richard
Georgia Regents University
Some students were supported by the
Summer Program in Obesity, Diabetes and Nutrition Related
Research Training (SPORT)
T35 DK095737-02
Steinle, Nanette
University of Maryland
Some students were supported by the
Vanderbilt Center for Kidney Disease
The NIDDK Medical Student Research Program and Symposium
were coordinated and hosted by the
Vanderbilt Diabetes Research and Training Center
P60 DK020593-37
Powers, Alvin
Vanderbilt University
16
NIDDK Medical Student Program Advisory Panel – 2014
Art L. Castle, PhD
Program Director
Metabolomics and Informatics
National Institute of Diabetes &
Digestive & Kidney Diseases
National Institutes of Health
6707 Democracy Blvd., Rm 791, MSC 5460
Bethesda, MD 20892-5460
[email protected]
James F. Hyde, PhD
Senior Advisor, Career Development
& Diabetes Centers Programs
Division of Diabetes, Endocrinology
and Metabolic Diseases
National Institute of Diabetes and
Digestive and Kidney Diseases
National Institutes of Health
6707 Democracy Blvd., Room 789
Bethesda, MD 20892-5460
[email protected]
Steven E. Kahn, MB, ChB
Professor of Medicine
Division of Metabolism,
Endocrinology & Nutrition
Director, Diabetes Research Center
University of Washington
VA Puget Sound Health Care System
1660 S. Columbia Way (S-151)
Seattle, WA 98108
[email protected]
Alvin C. Powers, MD
Joe C. Davis Chair in Biomedical Science
Professor of Medicine, Molecular Physiology
and Biophysics
Director, Vanderbilt Diabetes Research and
Training Center
802 Light Hall
Vanderbilt University Medical Center
2215 Garland Avenue
Nashville, TN 37232-0202
[email protected]
Michael R. Rickels, MD, M.S.
Assistant Professor of Medicine
Division of Endocrinology, Diabetes &
Metabolism
University of Pennsylvania School of Medicine
763 Clinical Research Building
415 Curie Boulevard
Philadelphia, PA 19104-6149
[email protected]
Louis H. Philipson, MD, PhD
Director, The University of Chicago Kovler
Diabetes Center
Professor of Medicine
University of Chicago Pritzker School of
Medicine
Chicago, IL
[email protected]
Sally Radovick, M.D.
Lawson Wilkins Professor of Pediatrics
Director, Division of Pediatric Endocrinology
The Johns Hopkins Hospital
Room 3125
200 N. Wolfe Street
Baltimore, MD 21287-2520
[email protected]
17
Abstracts from the Posters of the Students
Participating in the
2014 NIDDK Medical Student Research Program
(For abstract number see Table of Student Participants: pages 5 - 9)
18
Association between total cholesterol and at-risk psychosis symptoms among helpseeking adolescents.
Xavier Diao1, Caroline Demro2, Elizabeth Thompson2, Emily Kline2, Kristin Bussell1, Jason
Schiffman2*, Gloria Reeves1
1
University of Maryland School of Medicine, 2University of Maryland, Baltimore County
*Drs. Schiffman and Reeves served as Co-Mentors on this project.
Schizophrenia is a potentially devastating mental illness, characterized by perceptual
disturbances (e.g. hallucinations), delusional thoughts, and/or disorganized behavior. The
primary pharmacologic treatment, antipsychotic medication, can also cause physical health
problems through metabolic side effects (e.g. weight gain, new-onset diabetes). However, there
is evidence that metabolic abnormalities may be present in individuals with first-episode
psychosis prior to antipsychotic medication exposure, including hyperglycemia. It is unclear how
early these metabolic abnormalities can be detected over the course of mental illness, and also
if there is any association between specific psychotic symptoms and metabolic parameters. In
this study, we assess metabolic syndrome criteria in a sample of 51 antipsychotic-naïve
adolescents (15.45 ± 2.64 yrs old) receiving mental health services. Youth were screened for
“at-risk” psychosis symptoms (e.g. suspiciousness without overt paranoia) using the Structured
Interview for Psychosis Risk Syndromes (SIPS), and metabolic parameters (total cholesterol,
HDL-C, LDL-C, glucose, insulin, triglycerides, weight, height, waist circumference) were
measured after an overnight fast. We examined the relation between at-risk psychosis
symptoms and fasting metabolic parameters. We found that disorganized symptoms were
significantly correlated with total cholesterol (r = –0.39, p = .005) and LDL-C (r = –0.29, p
= .040). The correlation with total cholesterol remained significant after controlling for waist
circumference (r = –0.35, p = .015), and when participants with current stimulant use were
excluded from analyses (r = –0.41, p = .015). There was no significant association between atrisk psychosis symptoms and fasting glucose. The results of this pilot study, if replicated,
indicate a possible association between total cholesterol and disorganized symptoms that can
be detected in adolescence. Longitudinal studies are needed to assess the causal relation
between this metabolic parameter and psychiatric symptom over a course of illness.
Abstract
1
Mobile Health Messaging as a Tool for Behavior Change in Diabetes Management
Erin Butler, BS (Eastern Virginia Medical School), Charlene C. Quinn, RN, PhD, University of
Maryland School of Medicine, Department of Epidemiology & Public Health
Mobile health (mHealth) is rapidly expanding in healthcare allowing for patient care outside the
physician’s office to help prevent and manage chronic medical conditions. The Mobile Diabetes
Intervention Study (MDIS) evaluated a mobile communication system for patients with Type 2
diabetes. The primary study outcome was 1.9% mean change in HbA1c (mean difference from
control 1.2% (P<0.001) over a one year treatment period. Patients used a secure web portal to
record blood glucose, medication, and carbohydrate intake, and exchange messages with
diabetes educators. This secondary data analysis used a qualitative approach to describe
patient engagement, defined by content and quantity of messages, to determine if patient
engagement is related to change in HbA1c. This study is a mixed methods-qualitative,
quantitative analysis of the patient messages (n=3188) of three stepped treatment groups
(n=107); coach-only (CO), coach PCP portal (CPP), and coach PCP portal with decision
support (CPDS). Seven code themes (total 38 codes) were defined based on the American
Association of Diabetes Educators Self Care Behaviors for diabetes management, plus a code
for technical issues. Each message was coded based on content, and a quantitative analysis of
the results was performed. Modeling to determine the relationship of patient engagement and
HbA1c was performed. The patient engagement pattern followed the initial results of the study,
with CPDS group being the most engaged, followed by CO and CPP, respectively. Patients
messaged more about monitoring (mean 8.37 messages per patient) and healthy eating (mean
6.23 messages per patient) overall. Technical problems comprised a large proportion of
messages (mean 6.36 messages per patient). Accounting for non-substantive messages,
patients across the treatment groups sent 2.81 healthy eating substantive messages per patient
and 7.10 monitoring substantive messages. While further analysis of patient engagement
prediction of change in HbA1c is pending, these qualitative results indicate patients used
mhealth to engage with providers on self-care behaviors. This information can help further
develop mobile patient engagement tools.
Abstract
2
Examining Ethnic Disparities in Insulin Administration among Patients with Type 2
Diabetes
Nicolas Ludi (University of Tennessee Health Science Center) and Russell Rothman MD MPP,
Vanderbilt University, Nashville, TN
Latinos have a higher prevalence of T2DM and are disproportionately burdened with diabetes
complications. Insulin is an important treatment to optimize glycemic control in patients with
Type 2 Diabetes (T2DM), particularly for those with poor diabetes control. To date, little
research has examined the prevalence of insulin administration among Latinos with diabetes
versus non-Latinos. We believe that Latinos are less likely to be on insulin even after
adjustment for factors such as A1C, duration of diabetes, and insurance status. To test our
hypothesize we performed a cross sectional analysis of baseline data from a cluster randomized
trial examining the role of a literacy sensitive intervention to improve diabetes care in patients
seen at 10 separate Tennessee county health departments for the Vanderbilt PRIDE study. The
study partnered with the Tennessee Department of Health and included a total patient
population size of 400. Our analysis focused on the 98 patients who were self-identified as
Latino’s and compared them to the remaining 302 non-Latino individuals. The baseline data
collected included: patient characteristics, ethnicity from patient self-report, Subjective Literacy
Skills (SLS-3) test scores, Diabetic Numeracy Test (DNT-5) scores, diabetes medications, BMI,
and Hemoglobin A1C (from medical records.) Our results showed that almost 2/3 of T2DM
patients in this vulnerable population were on insulin therapy. However, Latino patients were
significantly (62% vs. 51%) less likely to be on insulin therapy. Lower likelihood of insulin usage
among Latinos remained even after adjustment for potential confounders. Additional research
is needed to examine potential etiologies for disparities in insulin therapy. Future interventions
could aim to reduce these disparities to optimize insulin therapy for Latino patients with diabetes.
The identification of insulin disparities among Latino’s is important because it is a factor that is
potentially modifiable. We hope that health care professionals can examine the data we
collected and use it to focus their care and improve the outlook of Latino patients.
Abstract
3
Prenatal drug exposure, stress reactivity, and adolescent drug experimentation, problem
behaviors and weight status.
Dayna Mazza (University of Maryland School of Medicine), Stacy Buckingham-Howes Ph.D.
and Maureen Black Ph.D., University of Maryland School of Medicine
Toxic stress, such as prenatal drug exposure (PDE), can alter the Hypothalamic-PituitaryAdrenal (HPA) axis, resulting in dysregulated stress reactivity, with long-term problems in child
health, development, and growth (Shonkoff et. al., 2012, Kirschbaum and Hellhammer 1989).
Although findings are controversial, some adolescents with PDE have a higher likelihood of
engaging in problem behaviors, including drug experimentation, and have a higher weight status
than non-exposed (NE) adolescents (Frank et. al., 2011, Lambert et. al., 2013, Shankaran et. al.,
2010). Little is known about the mechanisms, including the role of stress reactivity, underlying
these associations (Chaplin et. al., 2010, Lester et. al., 2010, Buckingham-Howes et. al., in
press). We hypothesize that among the NE group, typical stress reactivity is associated with few
problem behaviors and low BMI while no such associations are expected in the PDE group. The
study was conducted among adolescents mean age = 14.17 years (SD = 1.17; range = 11.9316.64) who varied in PDE exposure (PDE, n=76; NE, n=61) and had been followed since
delivery (PDE group), age 5 (NE group), or age 14 (additional NE group). The sample was 50%
male and 99% African American. Measured height, weight, cortisol (stress reactivity), caregiver
report of risk behaviors, and youth report and urine samples for drug use were collected. Overall,
45.3% of the sample was overweight/obese (BMI for age > 85th percentile) with no differences in
PDE status. The NE group was significantly more likely to react to a mild stressor than the PDE
group (26% vs. 12%; x2=4.49, p=.03), and the PDE group was more likely than the NE group to
experiment with tobacco/alcohol (25% vs. 10%; x2=4.76, p<.05). Within each group (PDE vs.
NE), we used linear or logistic regression to examine the association between stress reactivity
and problem behaviors and weight. The adolescents in the NE group with typical stress
reactivity engaged in fewer problem behaviors (any drug use: aOR=0.49, CI: 0.25-0.94, p<.05;
aggression: b=-4.99, p<.05) than adolescents with atypical stress reactivity. There was no
identifiable pattern within the PDE group. There was no association between stress reactivity
and weight status in the NE group (B=-.156, p=>.05); however, there was marginal significance
within the PDE group, showing an association between less stress reactivity and higher BMI zscore (B=-.871, p=.08). These results suggest that there may be a disruption of the HPA axis in
adolescents who are PDE, which blunts stress reactivity and interferes with expected
associations between stress reactivity and adolescent problem behaviors and weight status.
Future research is needed to further understand how PDE relates to the HPA axis and the role
that the stress reactivity system plays on behavioral and biological outcomes in youth exposed
to toxic stress.
Abstract
4
Effects of Vitamin D Supplementation on the Quality of Life in Patients with Type 2
Diabetes Mellitus.
Beatriz González Bouza (University of Puerto Rico School of Medicine)., Amy E. Riek, M.D.,
Robin R. Bruchas, MSW, Carlos Bernal-Mizrachi, M.D. Washington University School of
Medicine in St. Louis, MO.
Evidence suggests that vitamin D may influence both insulin secretion and sensitivity, and those
patients with type 2 diabetes mellitus (T2DM) that have a good glycemic control have reported a
better quality of life. The hypothesis was that
vitamin D supplementation over 4 months will help improve the quality of life of patients with
T2DM and who have low levels of vitamin D. A double blind, placebo controlled trial was
conducted and patients participating were randomized to receive either 4000 IU of vitamin D or
a placebo tablet. Both groups received 1.2g of calcium carbonate daily. Data collecting visits
were preform at baseline, 2 months and 4 months. Participants had their fasting glucose and
A1C’s measured and completed the Daily Quality of Life Survey. Results showed that there
were no significant differences in the answers between the groups and that only the questions
regarding the time to determine the blood sugars and the frequency of pain caused by the
treatment for diabetes showed a tendency to improve after the treatment in group A. More
patients are required to clarify the tendencies in the differences observed between the groups.
Abstract
5
Effect of Sestrin2 on signaling pathways of liver cancer cells.
Kathleen Estrada (Michigan State University), Hwan-Woo Park, Jun Hee Lee, University of
Michigan
Sestrin2 protein has been shown to prevent the development of type 2 diabetes and non-alcohol
fatty liver disease in mice placed on a high fat diet (HFD). During HFD-induced obesity, Sestrin2
was shown to suppress ER stress signaling and promote AKT signaling, both of which
contributes to the maintenance of metabolic homeostasis in liver. It has been recently shown
that HFD can promote liver carcinogenesis in a chemical (diethylnitrosamine, DEN)-induced
liver cancer model. Thus, we investigated how Sestrin2 affects liver carcinogenesis and ER
stress/AKT signaling pathways. We compared different ER stress markers and other signaling
markers in the liver tumors and non-tumor liver tissues of wild type mice and Sestrin2 knockout
mice that were fed HFD. We found that the expression of p-AKT was reduced in knockout mice
compared to wild type mice. However, ER stress markers p-eIF2α and BIP were elevated in the
knockout mice. These results confirm known relationships between Sestrin2, ER stress and
AKT signaling pathways in liver cancer cells. More studies will have to be done to fully
understand Sestrin2’s role in liver carcinogenesis.
Abstract
6
Pro-inflammatory pathways in the human colon: Relationships between toll-like receptor
4 (TLR4) and prostaglandin formation.
Tina Nigam (Michigan State University College of Human Medicine), Elkhansa Sidahmed,
Jianwei Ren, D. Kim Turgeon, Mack T. Ruffin, Dean E. Brenner, and Zora Djuric
University of Michigan
The Mediterranean diet has been shown to reduce the risk of cardiovascular disease and
diabetes, and this diet could have beneficial effects on preventing colon cancer as well. A proinflammatory state in the colon, with a key role in prostaglandin (PG) E2 formation, is known to
increase colon cancer risk. A Mediterranean diet, conversely, is thought to be anti-inflammatory.
This study evaluated the effects of a Mediterranean diet on genes involved in the proinflammatory response in the human colon. The hypothesis of this study was that exposure to
intestinal bacteria, as evidenced by induction of toll-like receptor 4 (TLR4), would be decreased
by a Mediterranean diet. Activation of TLR4 should increase PGE2, expression of enzymes
involved in PGE2 synthesis, and expression of the MUC2 gene, which is involved in formation of
mucin that protects the colon epithelial lining. To test this hypothesis, we used samples from a
clinical trial that randomized 120 high risk individuals into two diet groups (a Mediterranean diet
or a Healthy Eating diet) for 6 months. Colon biopsies were obtained by flexible sigmoidoscopy
without prior preparation of the bowels. Quantitative Real Time PCR using the standard curve
method was utilized to quantify gene expression. Expression of TLR4 and MUC2 was fairly high
in colon biopsies; however, neither gene showed significant changes in expression after dietary
intervention. At baseline, TLR4 expression was significantly and positively correlated with MUC2
expression and PGE2 concentration. Expression levels of both MUC2 and TLR4 were
correlated with expression of several genes in the PGE2 pathway: PTGS1, PTGES1, PTERG2,
and PTGER4. The especially strong correlation of TLR4 gene expression with enzymes in the
PG pathway was surprising and indicates the possible importance of exposure to intestinal
bacteria in stimulating pro-inflammatory pathways in the colon. Future work should better
characterize the factors that induce TLR4 and the mechanisms by which TLR4 activation could
induce the eicosanoid pathway in the human colon.
Abstract
7
Metabolic conditions extensively modulate the mRNA expression and circulating levels
of inflammatory cytokines.
Scott M. Whitlock (Eastern Virginia Medical School), Pia S. Petersen, X. Lei, M.M. Seldin, S.
Rodriguez, M.S. Byerly, A. Wolfe and G.W. Wong, Johns Hopkins School of Medicine
Cytokines play diverse and critical roles in innate and acquired immunity, and a few have been
shown to act in the central nervous system and peripheral tissues to modulate energy
metabolism. The extent of crosstalk between the immune and endocrine systems is not well
understood and has not been systematically examined. We hypothesized that circulating levels
of cytokines are dynamically regulated in response to physiologically relevant, short-term
(fasting and refeeding) or long-term (chronic high-fat feeding), metabolic perturbations.
We used a multiplex approach to profile changes in seventy-one circulating mouse cytokines in
response to acute (fasting and refeeding) and chronic (high-fat feeding) alterations in wholebody metabolism, and then used trizol RNA extraction and real-time PCR to analyze the
alterations in cytokine mRNA expression. Strikingly, refeeding significantly decreased serum
levels of IL-22, IL-1α, sIL-2Rα, sVEGFR2, and sVEGFR3, but markedly increased G-CSF, IL-16,
IL-1β, CXCL1, sIL-1RI, lipocalin-2, pentraxin-3, TIMP-1, and SAP relative to the fasted state;
these changes were accompanied, in part, by alterations in cytokine mRNA expression. In the
context of chronic high-fat feeding, circulating levels of CXCL1, SAA3, TIMP-1, and Alpha-2macroglobulin (A2M) were increased, whereas IL-12p40, CCL4, sCD30, sRAGE, CCL12,
CCL20, IL-16, IL-22, and haptoglobin were decreased relative to mice fed a control low-fat diet;
these changes accompanied alterations in cytokine mRNA expression. Our results demonstrate
that short- and long-term changes in whole-body metabolism extensively alter circulating
cytokine levels and gene expression. This study highlights the potential functional crosstalk
between the immune and endocrine systems, and provides a foundation to functionally
characterize the potential physiological role of cytokines in the context of metabolic
perturbations.
Abstract
8
Chronic Kidney Disease: Is Fibrin-Mediated Inflammation a Cause of Renal Capillary
Rarefaction?
Heather Cole BS1,2 Emily Smith2, Leslie Gewin MD3, Jonathan Schoenecker MD, PhD2
University of Tennessee Health Science Center, Memphis, TN 1,
Vanderbilt University Department of Orthopedics 2 and Department of Medicine3, Nashville, TN
Chronic kidney disease (CKD) affects one out of every seven adults in the United States
that ultimately involves peritubular capillary rarefaction (vascular regression) followed by
interstitial fibrosis and tubular atrophy. Despite numerous investigations into the mechanisms of
renal fibrosis, peritubular capillary rarefaction remains incompletely understood. Previous work
has established that persistent fibrin deposition within tissue results in increased local and
systemic inflammation. Because fibrinogen has been shown to be elevated in patients with
chronic renal failure and has been linked as a mitogen for tubulointerstial fibroblasts, we
hypothesized that inordinate fibrin within renal tissue potentiates chronic kidney disease through
peritubular capillary rarefaction. Using plasminogen-deficient mice as a model for defective
fibrinolysis, we performed angiographies to assess renal vascularity in relation to fibrin
deposition (immunofluorescence) and inflammatory response (IL-6 ELISA and F4/80
macrophage immunohistochemistry). Wild-type mice (C57/Bl6), plasminogen-deficient mice
(Plg-/-) 1, and mice deficient in plasminogen and the αMβ2 binding site of fibrinogen (Plg-/Fbgγ390-396A) _ENREF_102 were sacrificed at 20 weeks of age and analyzed. Our findings
demonstrate that impaired fibrinolysis leads to a pro-inflammatory environment with elevated
systemic IL-6 and fibrinogen levels, fibrin deposition in renal tissue, and significant increase in
F4/80 macrophages compared to WT. Interestingly, these findings are ameliorated in the Plg-/Fbgγ390-396 mice. Additionally, renal angiographies demonstrate a significant decrease in
renal vascularity in the Plg-/- mice that is normalized in the Plg-/- Fbgγ390-396 (15 weeks). As
inflammation has been identified as a contributing factor to capillary rarefaction and has been
associated with mortality in patients with chronic kidney disease, our findings suggest that fibrinmediated inflammation may be an inciting factor for chronic kidney disease.
Abstract
9
Effects of hyperglycemia and hyperlipidemia on mitochondrial dynamics in sensory
neurons
Nandini S. Abburi, B.S. (University of Toledo College of Medicine), Samuel W. Jackson, B.S.,
Gideon E. Levinson, B.S., Tatsuhito Himeno, Ph.D., Lucy M. Hinder, Ph.D., John M. Hayes,
B.S., Eva L. Feldman, M.D., Ph.D., and Stephen I. Lentz, Ph.D., University of Michigan – Ann
Arbor
Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes and is
characterized by a length-dependent loss of sensory nerve function. The mechanism by which
diabetes promotes the development and progression of neuropathy remains unknown.
Mitochondria are the primary source for cellular energy, and mitochondrial dysfunction has been
associated with a number of neurodegenerative diseases, including chemotherapy- and
diabetes-induced peripheral neuropathies. Studies from our laboratory and others have
identified hyperglycemia and diabetes-induced changes in mitochondrial dynamics, but recent
studies have also implicated hyperlipidemia as a potential disruptor of normal mitochondria
function. This current study investigates the effects of both hyperglycemia and hyperlipidemia
on mitochondrial trafficking in sensory neurons as a mechanism for sensory loss associated
with DPN. Live cell fluorescence microscopy was used to study the movement of individual
mitochondria within sensory neurites of primary cultured mouse dorsal root ganglion neurons.
Mitochondria were labeled with Mito-GFP (BacMam 2.0 encoding mitochondrial-targeted green
fluorescent protein; Life Technologies) and imaged every 2.5 sec for 2.5 min with a 40x oil (1.3
N.A) objective on a Nikon A1 confocal microscope. Kymographs (MetaMorph, Molecular
Devices) were used to quantify the percent motility, and the proportion and velocity of
anterograde and retrograde trafficking were for the following treatment groups: control, 0.5%
fatty-acid-free BSA solution control (BSA), 50 mM glucose (G), 0.5 and 2 mM palmitate (P), 25
mM glucose + 0.25 or 1 mM palmitate (G+P). All conditions and time points showed a similar
density of mitochondria within sensory neurites, with approximately 2-3 mitochondria per 10
microns of neurite. After 12 hours of treatment, P and G+P significantly lowered the percentage
of motile mitochondria compared to control, while BSA and G had no significant influence on
mitochondrial motility. After 12 and 24 hours of treatment, the P and G+P conditions showed
primarily anterograde movement, while retrograde motion dropped off entirely by 24 hours. The
results demonstrated that hyperlipidemia deleteriously reduced mitochondrial trafficking,
suggesting that dyslipidemia may be more influential in the development and progression of
DPN.
Abstract
10
Using Genotypes to Compare Clinical Presentation of Symptoms in Patients with
Wolfram Syndrome
Ian Milligan (Saint Louis University School of Medicine), Dr. Fumihiko Urano, MD, PhD,
Washington University in St. Louis
Wolfram syndrome (WS), also known as DIDMOAD, is a rare (~1/700,000), primarily autosomal
recessive disease characterized by the adolescent onset of diabetes mellitus and optic atrophy,
as well as the development of deafness, diabetes insipidus, and eventual neurodegeneration in
the cerebellum and brainstem. Mutations in the WFS1 gene have been implicated as the cause
for WS since the protein product, wolframin, has been associated with relieving endoplasmic
reticulum stress, thereby reducing cell apoptosis. Wolframin accomplishes this by regulating
cellular calcium levels and assisting with the proper folding of proteins such as proinsulin, a
precursor to insulin. The progression of disease in WS is highly variable, and has been
hypothesized to be associated with the type of mutations present in a patient’s WFS1 gene.
Blood samples taken from patients and their family members were sequenced to look for
mutations in the WFS1 gene and subsequently characterized. Genetic information was
correlated with a patient database constructed using REDCap software, which had
questionnaires regarding the onset and progression of symptoms. Mutations were found
throughout the WFS1 gene, with missense mutations being the most prevalent (39%, n=58),
and dominant mutations also being present (3.06%). Having two missense mutations was the
most common genotype, and was found to have delayed onset of diabetes mellitus (10.17 ±
5.87 years, n=6) and insipidus (18.00 ± 1.00 years, n=2) as compared to other genotypes.
Missense mutations were also found to be more prevalent (75%, n=2) in the slowly progressing
patient group, those patients diagnosed with diabetes mellitus after the age of 20. Dominant
mutations had an increased prevalence (50%, n=3) in the group of patients whose first
diagnosed DIDMOAD symptom was hearing loss. These patients also developed hearing loss
earlier (1.33 ± 1.04 years) when compared to all other patients (12.55 ± 9.06 years, n=28).
Overall, missense mutations appear to be associated with a milder phenotype, whereas
dominant mutations appear to be associated with deafness at a younger age. However, a
larger patient population is needed to more accurately depict disease progression and detect
differences between genotype and disease presentations.
Abstract
11
Application of SOMAscanTM Technology for Biomarker Discovery in Peripheral Arterial
Disease among Type 2 Diabetics
Christina Marcaccio (Perelman School of Medicine, University of Pennsylvania), Benjamin
Krieger, Kevin Trindade, Stephen R Master, Scott M Damrauer, Emile R Mohler, and Daniel J
Rader, University of Pennsylvania
Peripheral arterial disease (PAD) is a common manifestation of atherosclerosis and is a
significant cardiovascular complication of both type 1 and type 2 diabetes. Importantly, diabetes
is associated with increased risk for symptomatic PAD and higher morbidity and mortality rates.
Currently, there are few preventive and treatment therapies for PAD among diabetics because
the etiology and progression of PAD are largely unknown. Further, whether diabetic PAD is
fundamentally different that non-diabetic PAD remains poorly understood. Previous efforts to
gain a mechanistic understanding of diabetic PAD have used mass spectrometry-based
proteomic methods to assess circulating proteins in disease samples; however, this traditional
strategy is limited by issues of sensitivity, specificity, reproducibility, throughput, and cost. In this
study, we use a novel multiplexed proteomics technology for the discovery of circulating
biomarkers in diabetic PAD. Proteins are measured using a Slow Off-rate Modified Aptamer
(SOMAmer)—based capture assay called “SOMAscan” (SomaLogic, Inc). This approach uses
chemically modified nucleotides to transform each individual protein concentration into a
corresponding SOMAmer concentration, which is then quantified using relative fluorescence on
microarrays. The SOMAscan assay analyzes levels of 1129 circulating human proteins
representing a diverse set of molecular functions and disease processes across a wide range of
concentrations. We hypothesized that use of SOMAscan to assess the plasma proteome in type
2 diabetic subjects with PAD will identify novel protein biomarkers significantly altered in this
disease. To test this hypothesis, we identified from the extensive prospectively-consented
PennMedicine Biobank four patient subgroups: (1) T2 diabetic subjects with documented PAD;
(2) matched non-diabetic subjects with documented PAD; (3) matched T2 diabetic subjects
without PAD; (4) matched non-diabetic subjects without PAD. We use SOMAscan to analyze
plasma proteins in all four groups. Our primary aim is to identify plasma proteins that exhibit
significant differences in concentrations between group (1) and each of the control groups (2-4).
Novel proteins that differ in expression between groups will be further evaluated through ELISA
assays to confirm and accurately quantify the difference in protein concentrations between T2
PAD subjects and matched controls. Future studies will involve mechanistic assessment of
newly identified proteins to categorize molecular pathways that may be altered in diabetic PAD.
We hope that the identification of novel circulating biomarkers in PAD may advance
understanding of disease pathophysiology, identify novel therapeutic targets, and improve
disease management.
Abstract
12
Medication Management of Dippers Vs. Non-Dippers in the Systolic Blood Pressure
INTervention Trial (SPRINT)
Thomas Reed, George Washington University School of Medicine, Jamie Dwyer, M.D.
Vanderbilt University School of Medicine
Blood pressure (BP) is higher during the daytime (wake periods), and lower during the nighttime
(sleep periods). Recent studies have suggested that nocturnal systolic hypertension may be
more useful for prognosis than conventional BP measurements. We hypothesized that nondippers require more classes of medications to reach their target BP than dippers and would be
on higher dosage of medication at month 27 than dippers. We also hypothesized that nondippers will be at target BP for fewer study visits. Data was gathered on a host of variables such
as demographics, BP readings, medications, dosage, and a 24-hour ambulatory BP reading.
Using SPSS, data was analyzed using independent sample T-tests. Non-dippers spent on
average 5.1 study visits at target BP, whereas dippers spent on average 5.6 study visits at
target BP. Non-dippers were on an average of 3.0 classes of anti-hypertensive medicines per
visit, whereas dippers were on an average of 2.6 classes of anti-hypertensive medicines per
visit. Non-dippers had fewer visits at goal, more medications per visit, and a higher dosage of
medication at month 27. However, there was no significant difference in classes of medications,
time spent at target BP, or dosage of medication at month 27 between dippers and non-dippers.
Abstract
13
Renal interstitial cell plasticity underlies the hypoxic erythropoietin response.
Chad Binns (University of Arkansas for Medical Sciences), Hanako Kobayashi, Volker Haase,
Vanderbilt University Medical Center
One of the kidney’s responses to systemic hypoxia is to increase the production of
erythropoietin (EPO), a glycoprotein hormone responsible for erythropoiesis. Recombinant EPO
therapy has been utilized for patients suffering from anemia for the past two decades. Despite
its effectiveness, recent studies have raised questions concerning the safety of recombinant
EPO. Studying the kidney’s response to hypoxia may provide insight into how endogenous EPO
production may be boosted, resulting in the development of safer alternatives to recombinant
EPO therapy.
Endogenous EPO production is tightly regulated through the hypoxia-inducible factor (HIF)/HIF
prolyl-4-hydroxylase pathway. Under conditions of normoxia, constitutively expressed HIFα is
hydroxylated by prolyl-4-hydroxylase domain (PHD) proteins and subsequently tagged for
proteasomal degradation via von Hippel-Lindau (VHL) E3 ubiquitin ligase. Hypoxia impedes HIF
hydroxylation and consequent degradation, thus allowing for its nuclear translocation and the
transcription of hypoxia-regulated genes such as EPO.
The kidney controls EPO production by modulating the number of renal EPO-producing cells
(REPCs). REPCs are peritubular interstitial fibroblasts found in the renal cortex and outer
medulla. Fate-tracing studies have identified forkhead box D1 (FOXD1) expressing cells as
renal interstitial cell progenitors, a cell population containing all REPCs. Neural/glial antigen 2
(NG2) expression, a characteristic of renal pericytes, likely defines a subpopulation of FOXD1derived cells and, thus, REPCs. We tested the hypothesis that the REPC population is more
heterogeneous than currently characterized by comparing EPO expression in FOXD1 and NG2
cre-reporter mouse models. Crosses with floxed PHD2 lines were also utilized in order to
assess PHD isoform contributions to EPO expression in relation to these two REPC populations.
Studying EPO expression in these mouse models under normoxic and hypoxic conditions
allowed the comparison of REPC subpopulations.
Our initial findings, generated using a novel RNA in situ hybridization technique, indicate
heterogeneity within the REPC population such that knockout of PHD2, the primary PHD
isoform responsible for HIF-2α stabilization, is not sufficient to stimulate EPO production in all
REPCs – i.e. another hypoxia-dependent stimulus is required to induce EPO transcription in
some REPCs. Oxygen sensing mechanisms must, therefore, differ between REPC
subpopulations. These findings are reflected in FOXD1-lineage and potentially in NG2-lineage
REPC populations. While previous studies have compared PHD isoform sensitivity in wholekidney homogenizations, how oxygen sensing mechanisms differ has yet to be shown in a
spatial context. This study comparing FOXD1-lineage and NG2-lineage REPC subpopulations
will provide desired spatial resolution to the REPC population and, by extension, proof-ofprinciple that the REPC population is more heterogeneous than currently characterized.
Abstract
14
Sleep Disturbances and Hyperglycemia in Adults with and without Type II Diabetes
Ellora Sharma (Northeast Ohio Medical University), Emily A. Knapp, Jonathan C. Jun, MD,
Hsin-Chieh Yeh, PhD, Johns Hopkins University School of Medicine
Sleep disruptions and disorders are highly prevalent in today’s society and have been linked to
diabetes and the metabolic syndrome. Sleeping disturbances, deprivation, and sleep-disordered
breathing have been shown to decrease insulin sensitivity by activating the sympathetic nervous
system, increasing nonREM sleep duration, and increasing the expression of the enzymes of
fatty acid synthesis. The purpose of this study was to characterize diabetic status and sleep
issue status in the National Health and Nutrition Examination Survey participants and analyze
the 2011-2012 data set to determine if a significant relationship exists between the two statuses.
Self-reported diabetic condition and clinically obtained HbA1c levels were used to categorize
individuals into 6 diabetic categories ranging from no diabetes to poorly controlled diabetes.
Patients were categorized into either a sleep disturbance group, a sleep disorder group, or a no
issue group based on their responses to questions in NHANES’ sleep disorders questionnaire.
STATA 13 software was used to run logistic regression tests to evaluate the association
between diabetic status and sleep issue status. Results showed that having a sleep disturbance
was significantly associated with nearly all diabetic statuses and odds ratios for having a sleep
disturbance increased with severity of diabetic status. Patients with poorly controlled diabetes
were 1.77 times more likely than non-diabetic patients to have a sleep disturbance and 2.60
times more likely to have a sleep disorder. Sleep disturbances were reported in 43.2% of people
with poorly controlled diabetes and sleep disorders were reported in 25.7% of people in this
category. Having poorly controlled diabetes presented the greatest likelihood of having sleep
issues. Patients’ sleeping habits should be an area of additional concern when physicians are
treating diabetes and metabolic syndrome components.
Abstract
15
T Cell Based Detection of Autoreactivity In Type 1 Diabetes
Orly Leiva (Boston University School of Medicine), Russell Eason, Yulan Ai, Jason Gaglia,
Joslin Diabetes Center
Type 1 diabetes (T1DM) is caused by the autoimmune destruction of the insulin-producing
pancreatic beta cells. Currently, assessment of the risk of developing T1DM is done through the
detection of autoantibodies against beta cell antigens (βCAs) in the blood; however this
approach does not provide a direct insight into the intensity of the autoimmune response against
these cells at a given moment. Our lab is currently developing a T cell based assay to better
reflect disease activity at the point of testing. In order to produce sufficient quantities of relevant
βCAs , we are utilizing the BL21 Star strain of E. coli bacteria. We are currently working on
scaling up the synthesis of three proteins: chloramphenicol acetyltransferase (CAT), human
chorionic gonadotropin (hCG), and pre-pro-insulin (PPI). CAT will be used as a control in the Tcell assay, while hCG will act as a model protein for testing purposes and PPI is a βCA. We
transfected the bacteria with a plasmid containing: a T7 promoter, the sequence for our desired
protein (CAT, hCG, PPI), a lumio-tag for inducible fluorescence, a His-tag for purification and
finally a ampicillin (AMP) resistance gene for selection. The lumio-tag consists of the peptide
sequence, Cys-Cys-Pro-Gly-Cys-Cys, which binds to a biarsenical detection reagent allowing
visualization of the protein. Cells were transfected with the appropriate plasmid and grown
overnight in 50 mL of LB media with 1% AMP selection. The culture was then transferred to 1 L
of 2YT media with 1% AMP and was grown for approximately 2-3 hours to an OD 600 of 0.5-0.8.
PPI cultures were also supplemented with 1% glucose. To induce expression of the desired
protein, 0.5 mM (1 mM for PPI) isopropyl β-D-1-thiogalactopyranoside (IPTG) was used. Protein
expression resulted in inclusion body aggregates, which were then purified before purifying the
protein itself. The inclusion bodies were solubilized in 6 M guanidine-HCl solution and ran
through a column containing a Cobalt chelate resin. The presence of a His-tag on the denatured
proteins specifically allows for binding to the resin and the removal irrelevant proteins. Proteins
were eluted with a series of elution buffers with decreasing pH. Proteins were then tested for
endotoxin contamination. Protein production via this method will prove to be valuable in order to
acquire the protein needed for the new T cell assay the lab is developing to better test for
autoreactivity for T1DM.
Abstract
16
Short-term DPP4 inhibition improves glucose tolerance, reduces an inflammatory marker
and liver enzyme levels in HIV+ adults with glucose intolerance.
Paige Kuhlmann (University of Missouri School of Medicine), Heidi Struthers, Erin Laciny,
Michael Royal, Dominic Reeds, Kevin Yarasheski, Washington University in St. Louis
Introduction & Background. People infected with HIV are at higher risk for developing
metabolic complications such as insulin resistance, diabetes, and cardiovascular disease than
the general population. Chronic low-grade inflammation and treatment with highly active
antiretroviral therapy (HAART) contribute to the metabolic complications. Dipeptidyl peptidase-4
inhibitors (DPP4i) are glucose-lowering medications with potential anti-inflammatory and
pleiotropic actions that may benefit HIV+ people, but these beneficial actions have not been
tested in HIV+ adults with glucose intolerance. Hypothesis: In HIV+ adults with glucose
intolerance, DPP4i will improve indexes of glycemic control and ß-cell function, and reduce the
concentration of circulating inflammatory markers typically elevated in HIV+ men and women
(sCD14, CXCL10). Methods. We conducted a randomized, placebo-controlled, double-blind 8week trial of the DPP4 inhibitor sitagliptin (100mg/d) in HIV+ adults with glucose intolerance. We
measured oral glucose tolerance at baseline and week 8, and plasma markers of inflammation
(CXCL10), immune activation (sCD14), lipids/lipoproteins, and liver enzyme levels at baseline,
week 4 and 8 in placebo (n=12) and sitagliptin (n=16) recipients. Results. In comparison to
baseline, sitagliptin reduced plasma glucose concentrations during the oGTT (P< 0.03). Oral
glucose insulin sensitivity index (OGIS) improved in the sitagliptin group after 8 wk (P=0.029),
and there was a trend for this improvement to be greater than the change in the placebo group
(P=0.072). Other glucose-insulin indexes (HOMA-IR, HOMA-ß, IGI) were unchanged after
treatment in both groups. Plasma CXCL10 concentrations declined more in the sitagliptin group
than in placebo (p<0.007). Plasma sCD14 concentrations did not change significantly after
treatment in either group. Liver enzyme levels (SGOT, SGPT) were reduced more in the
sitagliptin group than in the placebo group after 8 weeks (P<0.005). No within or between group
differences were observed for fasting serum triglycerides, total-, LDL-, or HDL-cholesterol levels.
Conclusion. In HIV+ men and women, sitagliptin (100 mg/d for 8 wk) improved glucose
tolerance, apparently by enhancing insulin sensitivity. Sitagliptin appeared to induce other
effects that might benefit HIV+ individuals with cardiometabolic complications; it reduced liver
enzyme levels, suggesting a beneficial effect on liver health, and it reduced a circulating marker
of inflammation.
Abstract
17
Use of Magnetic Resonance Spectroscopy to Measure Intrahepatic Lipid and Percentage
Liver Fat in Nonobese Adolescents with Polycystic Ovary Syndrome
Alexandra N. Linder (Tulane University School of Medicine), Dr. Sharon E. Oberfield, Tamara
Cameo, Donald J. McMahon, Dr. Aviva B. Sopher. Division of Pediatric Endocrinology,
Columbia University Medical Center, New York, NY.
Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects adolescents
and women of reproductive age. Insulin resistance is thought to be an underlying cause of
PCOS. A combination of genetic predisposition, insulin resistance and elevated androgens seen
in this population may lead to development of non-alcoholic fatty liver disease (NAFLD), which
can be considered the hepatic manifestation of the metabolic syndrome. Magnetic resonance
spectroscopy (MRS) is a non-invasive tool for evaluating the presence of NAFLD by quantifying
intrahepatic lipid measurement (IHL) and highly correlates with the gold standard, liver biopsy.
There have been several studies using MRS in obese adults with PCOS for evaluation of
NAFLD but this method has not yet been used to evaluate non-obese adolescents with PCOS
for NAFLD. We hypothesize that non-obese adolescents with PCOS have significantly higher
percentage liver fat compared to age-, BMIz-, and ethnicity comparable- controls, and that
percentage liver fat in PCOS is correlated with metabolic abnormalities including insulin
resistance and dyslipidemia. We studied 34 non-obese adolescent girls between ages 13 and
21 (16 PCOS and 18 controls), with: physical exam with Ferriman-Gallwey hirsutism score,
fasting blood tests for reproductive and adrenal hormones and lipids, two hour oral glucose
tolerance test, whole body DXA for percentage body fat, and MRS for IHL. Percent liver fat was
calculated from IHL data obtained by MRS. As expected, the PCOS group had significantly
higher Ferriman-Gallwey scores, and in a menarcheal age adjusted analysis had higher T, free
T, DHEAS, androstenedione, and FAI, and lower estradiol and SHBG than controls. Percentage
liver fat was not significantly higher in PCOS compared to controls, nor was incidence of NAFLD.
There was a statistical trend in the PCOS group for correlation between percentage liver fat and
triglycerides (r=0.48, P=0.057) and percent body fat (r=0.49, P=0.057). There was a negative
statistical trend in the control group for correlation between percentage liver fat and LDL (r=0.41, P=0.09), HOMA (r=-0.38, P=0.12), and percent body fat (r=-0.39, P=0.11). Although this
small study did not find any significant differences in liver fat, the metabolic abnormalities,
including insulin resistance and elevated triglycerides, found in adolescents with PCOS suggest
that this population may be at risk of later developing other components of the metabolic
syndrome, including NAFLD. These findings suggest that non-obese adolescents with PCOS
should be monitored closely and that interventions with insulin sensitizing drugs such as
metformin may be considered to prevent metabolic abnormalities and future cardiovascular
disease and type 2 diabetes mellitus.
Abstract
18
Polymorphisms in three genes may contribute to the expression of hypogonadotropic
hypogonadism.
Megan Foggia1, Cuiqi Zhou2, Ahmed Khattab3, Maria New3, Shlomo Melmed2
1
University of Nevada School of Medicine, Reno, NV 2Cedars-Sinai Medical Center, Los
Angeles, CA, 3Mount Sinai Hospital, New York, NY
Isolated hypgonadotropic hypogonadism (IHH) is a condition which occurs in the absence of
gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus, or a failure of the
gonadotropins to act at the level of the testes and ovaries. Many cases of IHH have been linked
to genetic polymorphisms in genes such as the GnRH receptor gene, KAL1, KISS1, and
PROK2. In addition, there are a number of genes associated with the hypothalamic-pituitary
axis which have not been extensively studied, but may play a role in the expression of IHH. This
study focuses on a male patient who was diagnosed with IHH of unknown cause. Whole exon
sequencing of the patient’s genomic DNA revealed more than 600 single-nucleotide
polymorphisms (SNPs) in more than 70 different genes. Nine of these SNPs were selected for
further validation based on their location in coding regions of genes associated with the
hypothalamic-pituitary axis and the regulation of GnRH. The SNPs were confirmed via
polymerase chain reaction, and were further validated via sequencing. After validation, the
SNPs were evaluated, revealing that four out of the nine polymorphisms were uncommon
amongst populations in the NCBI database. The four uncommon SNPs occurred in the following
genes: TAF7L, MAMLD1, and NR0B1. These SNPs in TAF7L, MAMLD, and/or NR0B1 may be
linked, directly or indirectly, to the expression of IHH in this patient. Further studies on the
mutant proteins resulting from variations in TAF7L, MAMLD, and NR0B1 are needed to evaluate
whether or not polymorphisms in these genes are associated with IHH.
Abstract
19
Nutrition, Inflammation, and Insulin Resistance in End Stage Renal Disease
Sthuthi David (University of Rochester School of Medicine and Dentistry), Serpil M. Deger MD,
Gerald B. Denny MD, Feng Sha PHD, Charles D. Ellis PHD, Alp Ikizler MD, Vanderbilt
University Medical Center.
Patients receiving chronic hemodialysis (CHD) exhibit a metabolic derangement characterized
by inappropriate loss of skeletal muscle mass, termed protein energy wasting (PEW). CHD
patients who exhibit PEW have higher mortality and hospitalization rates. The mechanism of
PEW is complex but may be related to insulin resistance and chronic inflammation. We
hypothesize that there is a direct correlation between glucose and amino acid metabolism,
related to diminished insulin action seen in the maintenance hemodialysis population. To test
this hypothesis, we utilized the hyperinsulinemic euglycemic and euaminoacedemic dual clamp.
So far, we have done this study on seven hemodialysis and five control patients. Within two
weeks of taking part in the metabolic clamp study, subjects underwent a dual-energy x-ray
absorptiometry (DEXA). Patients were also asked to eat based on current dietary
recommendations during the two weeks before the study. At the beginning of the dual clamp
study, baseline blood samples were drawn and patients received a bolus and continuous
infusion of labeled leucine, phenylalanine, and glucose. After the equilibration period of two
hours, subjects received an insulin infusion of 60 mU/m2/min and baseline glucose levels were
maintained by infusions of dextrose. In the second study, a prime constant infusion of 10%
balanced amino acid solution was begun to increase plasma leucine levels. Insulin sensitivity
was assessed by the glucose disposal rate (GDR) derived from HEGC. Median GDR level was
4.9 for hemodialysis patients and 4.4 mg/kg/min for control patients (p=.905). Amino acid
infusion induced a significant rise in GDR in hemodialysis patients. GDR was increased in
controls but did not reach statistical significance. Leucine disposal rate (LDR) was similar in
both groups and averaged .68 ±.23 and .44 ± .47 mg/kg/min in hemodialysis and control
subjects, respectively (p=.268). There was a strong positive correlation between LDR and GDR
(r=.883, p=.002). In conclusion, the results of this study indicate that the severity of insulin
resistance to carbohydrate metabolism is associated with a similar resistance to anabolic
actions insulin has on protein metabolism in CHD patients. This implies that insulin resistance
may represent a potential target for prevention or treatment of PEW in CHD patients.
Abstract
20
The Use of Electronic Communication Media and Evaluation of Living Kidney Donors
Mari Tanaka (Georgetown University School of Medicine), Anthony Dreher, Powell Newbern,
Irene Feurer PhD, and Heidi Schaefer MD, Vanderbilt University Medical Center
A proposed reason why it has been difficult to increase the number of living kidney donors is
that many potential donors lead busy lives and find the pre-donation process too lengthy and
burdensome. Most transplant centers initially screen donors using phone or written surveys,
which limit the time during which self-referring donors can initiate the process. With this in mind,
Vanderbilt University Medical Center implemented a web-based application in 2011 where
potential donors could privately initiate the process and proceed through the initial screen
anytime from the comfort of their home and/or office resulting in an increase in the number of
self-referrals. To test the hypothesis whether or not patients who interface through electronic
tools with the transplant center have expedited living donor evaluations, surgeries, and
increased conversion rate we conducted a single center retrospective study using patients who
interfaced with the Vanderbilt transplant center between January 2011 – March 2014. Data
were analyzed using t-tests, nonparametric tests of proportions, Kaplan-Meier survival, and
multivariable Cox proportional hazards regression methods. Our results indicate that patients
who contacted via the web are more likely to have a graduate degree and to live more than 400
miles away from the transplant center. There were no significant associations between contact
methods and time to evaluation, decision regarding candidacy, or donation surgery between
groups. Lastly, those who contacted via the phone were more likely to be turned down for
donation while those who contacted via the web were more likely to decide not to donate.
These findings suggest that the web-based application increases the overall number of living
donor surgeries performed but has no effect on the times to evaluation, eligibility decision, or
surgery. Future efforts should be aimed at those patients who decide not to donate and
reasons why to determine if modifiable factors are present that could be addressed by the living
donor program in hopes of further increasing the number of eligible living donors.
Abstract
21
Myeloid lineage-specific overexpression of P110α induces vascular lesions in mice
Jeremy Brooksbank, Vladimir R. Babaev, PhD, Sergey V. Ryzhov, PhD, Lei Ding, Youmin
Zhang, and MacRae F. Linton, MD
Phosphoinositide 3-kinases (PI3Ks) signaling is downstream of multiple cell-surface receptors
that regulate cell proliferation, survival, and death. Activation of receptor tyrosine kinases and
growth factors induces PI3Ks activity with formation of heterodimers of class Ia lipid kinases,
composed of the P110 (catalytic) and p85 (regulatory) subunits. These heterodimers propagate
secondary messenger signaling by phosphorylating phosphatidylinositols (PIP2 to PIP3) and
initiating Akt signaling. Due to the association between P110α and pathologic angiogenesis, it is
believed to be a promising drug target.
In order to examine the role of PI3Ks in macrophage functions and atherogenesis, we recently
generated mice with conditional myeloid lineage-specific overexpression of P110α (MS-P110a+)
induced by the LysM Cre promoter. These mice exhibit a striking phenotype with massive
venous enlargement in the extremities. Here we demonstrate that these MS-P110a+ mice
develop venous enlargement in the tail, feet, and ears progressively over time with frequent
hemorrhage of the varicose veins of the tail at 4-5 months of age. The endothelial cell lining of
the dilated veins is preserved as demonstrated by staining with antibodies (Abs) to vonWillebrand factor and pan-endothelial cell antigen. Venous dilation and remodeling with
increased vascular permeability promoted extravasation of erythrocytes into the interstitial
space. With the phagocytosis of RBCs by tissue macrophages, Fe and hemosiderin were
deposited around the lateral veins in the tail. This iron accumulation and enlargement of
peripheral veins is consistent with chronic venous diseases in humans such as varicose veins.
In addition to peripheral enlargement of veins, MS-P110α mice exhibit marked splenomegaly
with effacement of normal architecture, increased granulocytes, and decreased numbers of Bcells. Macrophages isolated from MS-P110α+ mice constitutively express increased activity of
Akt with a compensatory increase in the levels of phosphatase and tensin homolog (PTEN),
which is an inhibitor of PIP3 and Akt and downstream signaling pathways. RT-PCR of gene
expression in MS-P110α+ macrophages shows decreased levels of pro-inflammatory cytokines
like TNF-α and IL-12 with elevated anti-inflammatory cytokines like IL-10, indicating that these
macrophages are of the M2 phenotype. In addition, we found increased levels of matrixmetalloproteinase-2 (MMP-2) and inducible-nitric oxide synthase (iNOS) in macrophages, which
may be critical for the pathogenesis of these vascular lesions.
Finally, we used bone marrow transplantation (BMT) to examine the hypothesis that the
myeloid-specific overexpression of P110α is sufficient to recapitulate the vascular phenotype.
Examination of these mice at 4 and 8 weeks post-BMT revealed the presence of similar
vascular lesions in both tail and spleen to the original MS-P110a+ mice. These results strongly
support the hypothesis that myeloid specific overexpression of P110a is sufficient to induce the
venous malformations and highlight a previously unappreciated role of macrophages in vascular
remodeling. Thus, we have developed a new murine mouse model for chronic venous disease
that should allow the identification of novel targets for pharmacologic intervention to slow or
prevent the development of varicose veins.
Abstract
22
Identification of BBMP-3 as a betatrophin binding membrane protein
Poy Theprungsirikul (Geisel School of Medicine at Dartmouth), Qian Huang, Ph.D., and Peng Yi,
Ph.D., Joslin Diabetes Center-Affiliate of Harvard Medical School
Replenishing the insulin-producing β-cell mass is considered to be a potential cure for diabetes.
One possible avenue to replenish β-cell mass is via replication of pre-existing β-cells in the
pancreas. Betatrophin, a secreted protein in liver and fat that belongs to the angiopoietin-like
protein family, has been found to cause an increase in pancreatic β-cell replication and improve
glucose tolerance in mouse models. However, the mechanism of action of betatrophin is not yet
fully understood. The goal of this study was to identify betatrophin binding protein(s)/receptor(s)
in hope to understand the mechanism behind how betatrophin induces pancreatic β-cell
proliferation and β-cell mass expansion. To identify betatrophin binding protein(s), we prepared
cDNA expression libraries from mouse liver and fat, and screened the libraries with an alkaline
phosphatase-mouse betatrophin (AP-mBT) fusion protein. We identified Betatrophin Binding
Membrane Protein (BBMP-3) in the mouse liver. The identified BBMP-3 is a major subunit of a
single transmembrane glycoprotein receptor that is expressed primarily in liver. It plays a role in
serum glycoprotein homeostasis by mediating the endocytosis and lysosomal degradation of
glycoproteins with exposed terminal galactose or N-acetylgalactosamine residues. We
speculate that BBMP-3 may play a role in regulating serum betatrophin level. The identification
of BBMP-3 as a betatrophin binding membrane protein may have important implications for the
development of betatrophin receptor modulators for treating both type I and type II diabetes.
Abstract
23
The Prevalence of Copper Deficiency before and after Bariatric Weight Loss Surgery
Jordan Martinez (Jefferson Medical College), John LaBarra, Joe Boullata, & Charlene Compher,
The University of Pennsylvania
Bariatric surgery is one of the only current, long term treatment options used to increase the
quality of life within the obese population. This surgical option allows patients to attain
considerable weight loss and also helps improve several comorbidities associated with obesity
such as diabetes, high blood pressure and cholesterol, and arthritis. Even though it is very clear
that there are many benefits associated with bariatric surgery, these operations also have quite
a few potential complications. Particularly, patients who have received bariatric surgery have
shown to be at risk for a variety of important nutritional deficiencies. Serum copper deficiency is
one of the nutritional deficiencies that has been reported in the literature within the postoperative obese population. The purpose of this clinical study is to understand how serum
copper levels change within patients who undergo bariatric surgery. We want to know the
prevalence of being copper deficient both before and after surgery. By studying new patients
and reviewing the current literature, the revision of current recommendations and treatment
options can be prepared and any uncertainties in the relevant literature can be identified and
serve as targets for future research pertaining to bariatric patients and their serum copper levels.
The ultimate goal for this clinical study is to be able to help these bariatric patients attain the
highest quality of life by ensuring they receive the necessary copper supplementation that is
needed to prevent deficiency and any associated symptoms.
Abstract
24
CRISPR-Cas9 mediated MMP10 deficiency may impact macrophage polarization in THP-1
cells.
Natasha Choudhury (Meharry Medical College, School of Medicine), Barbara Fingleton,
Vanderbilt University
MMP10 (matrix metalloproteinase 10 or stromelysin-2) deficiency has been implicated in
depressed resolution of colonic inflammation and increased risk of colitis-associated cancer
development. In a mouse model of colitis, MMP10 expression was shown to be predominant in
macrophages. The phenotype of MMP10-null mice in this model was deficient in macrophages
over time, with a skewing toward the M1 (classically activated) macrophage profile. This may
suggest that macrophages may be required for wound healing in models of colonic damage;
and M2 (alternatively activated) macrophages may be protective against colitis. To test the
hypothesis that MMP10 deficiency in undifferentiated monocytes results in a skewing toward the
M1 profile and significant decrease in development toward the M2 profile during polarization; we
utilized the CRISPR-Cas9 system, an RNA-guided targeted genome editing technology, to
induce an MMP10-null line of THP-1 monocytic cells and characterize their polarization. First,
we used a standard monocyte/macrophage cell line, Raw 264.7 murine cells, to serve as a
control for analysis of MMP10 expression and polarization ability. Next, we analyzed THP-1
monocytic cells for base levels of MMP10 expression and polarization ability. Transfection of
THP-1 cells was achieved by addition of plasmid DNA-lipid complexes (MMP10-Cas9-GFP
plasmid; Lipofectamine 2000 Reagent) to cells; GFP expression was used to assess
transfection efficiency. Finally, transfected cells were serially diluted in order to establish clonal
cells suitable for analysis of MMP10 expression and polarization ability. MMP10 expression was
shown to be present in both Raw 264.7 and THP-1 cells; polarization ability in Raw 264.7 cells
yielded predictable results. The CRISPR-Cas9 system proved to be simple, rapid, and efficient;
and yielded high transfection efficiency (~85-90%) in THP-1 cells. However, analysis of MMP10
expression and polarization ability of transfected THP-1 cells depends on further expansion of
clonal cells. Therefore, the relationship between MMP10 and macrophage polarization in
models of colitis has yet to be clarified further.
Abstract
25
KrasG12D mutation in pancreatic duct cells results in the development of pancreatic ductal
adenocarcinoma precursor lesions
Jessica N. Kim (University of Nevada School of Medicine), Fong C. Pan, R. Daniel Beauchamp,
Christopher V. Wright, Anna L. Means, Vanderbilt University Medical Center
90% of human pancreatic carcinomas have a Kras mutation; murine models of pancreatic ductal
adenocarcinoma (PDAC) have demonstrated that Kras mutation and subsequent inflammation
result in the development of pancreatic cancer precursors (PanINs). While PanINs and PDAC
have ductal characteristics, acinar cells can convert to duct cells following an inflammatory
event, making it unclear whether acinar or duct cells give rise to pancreatic cancer. We
hypothesize that Kras mutation in duct cells results in the development of PanIN lesions in the
setting of clinically relevant inflammation. Mice with Kras mutation in either duct or acinar cells
underwent partial duct obstruction via partial ligation of the main pancreatic duct, mimicking a
type of damage observed in humans, and analyzed at different time points. When Kras mutation
was introduced into duct cells, ducts gave rise to dysplastic lesions but when Kras mutation was
introduced into acinar cells, the tissue resembled wild-type pancreas with most KrasG12D cells
lost by 4 months post-ligation. We found that Kras mutation supplies a selective advantage
when introduced to duct cells in the setting of inflammation as early as 2 weeks after injury: Kras
mutant cells were enriched in damaged parts of the pancreas compared to undamaged parts.
To understand this selective advantage, double IF studies with PHH3 (a marker of proliferation),
histone γH2AX (a marker of double strand DNA breaks), and cleaved caspase-3 showed that a
survival, rather than proliferative, advantage is conferred to duct cells with KrasG12D. Finally, we
found that Kras mutation in duct but not acinar cells maintained a fibrotic microenvironment
similar to that found in human PanINs, confirming the ductal origin of these precancerous
lesions. In summary, KrasG12D in duct cells provides these cells a survival advantage, resulting
in the development of PanIN lesions and the maintenance of a fibrotic tumor microenvironment.
These observations have implications for the pathway in which Kras mutant cells survive,
potentially revealing possible drug targets and diagnostic biomarkers of PDAC.
Abstract
26
Women with the Comorbid Condition of Obesity and Depression Have Improved Body
Composition, Eating Behaviors, Inflammation and Insulin Resistance Upon Consuming a
Balanced High Fat Diet
María E. Mulero Morales, Ponce School of Medicine & Health Sciences; Heidi J. Silver, Ph.D.,
R.D., Vanderbilt University School of Medicine
Background: Obesity and depression are comorbid conditions; obese adults are 55% more
likely than normal weight adults to become depressed and depressed adults are 58% more
likely to become obese. This bidirectional relationship is influenced by sex, age, dietary
behaviors, body size, body image, inflammation, and insulin resistance. Moreover, both
conditions are associated with increased risk for type 2 diabetes and cardiovascular disease.
Hypothesis: We hypothesized that consuming a balanced high fat diet, previously shown to
decrease weight, body fat, and retain lean body mass in obese premenopausal women, would
improve eating behaviors, inflammation, oxidative stress, insulin resistance, and thereby,
promote decreased prevalence of depression and improved quality of life. Methods: 144
premenopausal women aged 21-50 with Class I/II obesity (BMI 30-39.9 kg/m2) were enrolled in
a 16-week higher fat diet intervention where type of fat was balanced as 1/3 saturated, 1/3
monounsaturated, 1/3 polyunsaturated. History of depression was self-reported and verified by
review of medical record diagnosis and/or anti-depressive medication prescription. Dietary
intake was assessed by computerized 24-hour recall interviews at random time-points using
NDSR software. Body composition was assessed by DEXA. Eating behavior was assessed
using the Three Factor Eating Questionnaire (TFEQ) and the Eating Attitudes Test (EAT-26).
Inflammatory markers (hsCRP, PAI-1 antigen, pro-inflammatory cytokines), fasting glucose and
fasting insulin were assayed at the Vanderbilt Pathology Lab. Urinary F2-Isoprostane metabolite
was assayed at the Roberts Lab. Insulin resistance was estimated by calculating HOMAIR score.
Quality of life was assessed using the Impact of Weight on Quality of Life-Lite (IWQOL-Lite)
questionnaire. Results: At baseline, 63 (46.1%) of subjects had a history of depression. At
week 16, women with depression had significant improvements in weight, BMI, VAT, TFEQ
scores, EAT-26 oral control, pro-inflammatory cytokines (IFNγ, IL-1α, IL-6), F2-Isops, glucose,
insulin, HOMAIR score, and quality of life (all ps < 0.05). In addition, women with depression had
significantly greater improvements compared to non-depressed women in fasting glucose (p =
0.04), IL-6 (p = 0.06), TFEQ disinhibition (p = 0.05) and TFEQ total score (p = 0.007). Overall,
prevalence of depression decreased from baseline to week 16 by 6.1% (p = 0.001).
Conclusions: Effective lifestyle interventions for obese adults with depression are much
needed. In this cohort of obese women, both body weight and body composition improved
substantially upon consuming a higher fat diet where the type of fat was balanced. In addition,
depressed women had significant improvements in eating behaviors, inflammatory markers,
insulin resistance, and quality of life. Moreover, the balanced high fat diet appeared to have a
significant impact on the prevalence of depression. Future work with dietary intervention is
needed using a standardized method for determining a meaningful change in depressive
symptoms and remission rate.
Abstract
27
Quantification of urinary exosomal NPT2a co-transporter expression may serve as a
marker for phosphate reabsorption
Si Liao (New York Medical College), Taopheeq Ayodele Mustapha, James Matthew Luther,
Vanderbilt University
Enrichment of proteins isolated from urinary exosomes may offer insight into the
pathophysiological state of renal tubular cells and the potential for non-invasive detection,
classification, and monitoring of renal disease. We have previously identified proteins, including
NPT2a (type IIa sodium-dependent phosphate co-transporter), TRPV5 (epithelial calcium
channel), and klotho in urinary exosomes via Multidimensional Protein Identification Technology
(MudPIT). These proteins play an essential role in calcium and phosphate handling. Phosphate
handling is impaired in chronic kidney disease (CKD) where increased serum phosphate levels
is associated with increased cardiovascular mortality and decreased in kidney transplant
patients who experience phosphate wasting. Renal phosphate reabsorption is primarily a
function of hormonal regulation of NPT2a expression on the apical membrane of proximal tubule
cells, and has been shown to increase with insulin. Therefore, we hypothesized that insulin
increases renal phosphate reabsorption and expression of NPT2a in urinary exosomes. To
validate exosomal NPT2a as a marker for phosphate reabsorption, differential
ultracentrifugation was performed to isolate exosomes from human urine samples collected
before and after high-dose hyperinsulinemic clamps (120 mU/m2/min), followed by an in-solution
trypsin digest in preparation for multiple reaction monitoring (MRM) coupled with stable isotope
dilution mass spectrometry. The tubular reabsorption of phosphate (TRP) was calculated from
plasma and urine concentrations of phosphate and creatinine before and after insulin infusion in
seven subjects. Mean plasma phosphate concentration decreased from 1.62±0.057 mM preinsulin infusion to 1.39±0.050 mM post-insulin infusion (P<0.001). Mean TRP increased from
89.86±6.40% pre-insulin infusion to 91.61±6.70% post-insulin infusion (p=0.48). Trypsin digests
of urinary exosomes have been prepared and are awaiting analysis for NPT2a peptide
fragments. NPT2a expression in urinary exosomes may allow assessment of novel treatment of
renal disease, including phosphate retention in CKD and phosphate wasting in kidney transplant
patients.
Abstract
28
The Effects of Low Dose Metformin on Hepatic Glucose Production
Gaurav Pahouja (Northeast Ohio Medical University), Sara M. McMillin, Fredric E. Wondisford,
Johns Hopkins University School of Medicine
One of the leading chronic illnesses in the United States is type 2 diabetes, afflicting nearly 1 in
every 10 people. Metformin is considered the first line therapy and standard of care for type 2
diabetics. However, the exact mechanism by which metformin lowers blood glucose values is
still under debate. To date, the majority of rodent studies have utilized high doses of metformin
given in a manner (i.e. intravenous injection) that does not accurately represent the normal oral
delivery of metformin in patients. Therefore, we set out to investigate the effects of low dose
metformin given orally to better reflect the patient model and normal metabolism of the drug.
Mice that contained a floxed version of the gene for the PKA regulatory subunit R1a were
treated with adenovirus coding for CRE recombinase to knockout the R1a regulatory subunit in
the hepatocytes and achieve constitutive activity of PKA. Subsequently, a group of the Ad-CRE
treated mice were given a low dose, 12.5 mg/kg/day, of metformin in the drinking water. When
compared to mice given Ad-CRE alone, the mice that received Ad-CRE and metformin showed
significantly lower blood glucose levels. In addition, a pyruvate challenge test also showed a
significantly lower rise in blood glucose values in the mice treated with metformin as compared
to the mice receiving only the virus. Finally, the activation of AMPK, tracked by the presence of
Phospho-AMPKα (Thr 172), increased in the hepatocytes of the mice treated with metformin but
did not increase in the skeletal muscle. These results indicate that metformin was active in the
liver, even at such a low dose. A larger scale study is currently underway to confirm these novel
findings.
Abstract
29
Effects of Maternal Obesity during Pregnancy on Insulin Signaling in Human Umbilical
Vein Endothelial Cells
Kacie Fox, John A. Burns School of Medicine- University of Hawaii, Elvira Isganaitis, Joslin
Diabetes Center
There is now a substantial body of evidence linking maternal obesity during pregnancy and
gestational diabetes to metabolic dysfunction in offspring. It is likely that in addition to genetics
and the postnatal environment, the intrauterine environment programs metabolic activity in
offspring tissues, resulting in increased risk for obesity and type 2 diabetes. However, the
mechanisms are still not well understood. We hypothesized that maternal obesity alters insulin
signaling in fetal cells. To test this hypothesis, we obtained umbilical cords from a cohort of 35
women across the BMI spectrum undergoing scheduled C-sections at Brigham and Women’s
Hospital. Human Umbilical Vein Endothelial Cells (HUVEC) were isolated and grouped
according to maternal weight status: lean – BMI < 25, overweight – BMI 25-30, and obese –
BMI > 30. Primary HUVEC were stimulated with insulin (1 and 10 nmol) before extracting
protein, RNA & DNA. We examined the expression and phosphorylation of IR, IRS1, AKT, ERK,
and FoxO1 proteins by Western blotting. Our preliminary analyses indicate that these proteins
respond to insulin in a dose responsive fashion and that protein expression of phosphorylated
IRS-1 is increased in fetal cells exposed to maternal obesity. Examination of transcriptional
responses to insulin is underway. Our data will help advance the understanding of mechanisms
by which maternal weight status during pregnancy influences risk of metabolic dysfunction in
offspring.
Abstract
30
Patients’ Satisfaction with a Medication Adherence Support Website: Diabetes MAP
Sujata Ghosh, MPH (Texas A&M Health Science Center), Magaela C. Bethune, MPA, Chandra
Y. Osborn, PhD, MPH Vanderbilt University
Among adults with type 2 diabetes mellitus (T2DM), nonadherence to medications is common,
and is associated with worse glycemic control, hospitalizations, and pre-mature death. Effective
medication adherence promotion interventions have not been feasible and sustainable in busy
clinic settings. Web-delivered interventions are a viable alternative. However, their effectiveness
depends on patient use, which is determined by many factors, including user satisfaction. We
conducted a mixed methods study to understand patients’ satisfaction with a medication
adherence promotion intervention website called Diabetes MAP.
We recruited adult patients with T2DM who were prescribed diabetes medications (N=32) from
an academic medical center for a three-part usability evaluation. Participants completed an
initial survey (N=32), were instructed to independently use Diabetes MAP for two weeks (n=29),
complete a follow-up survey, and participate in a focus group session (n=27). Positive
comments from focus group transcripts were extracted, coded, and analyzed using thematic
analysis. Survey data were analyzed descriptively, and linked to transcripts to characterize
qualitative data.
Most participants reported being satisfied with using Diabetes MAP in the follow-up survey
(69%) and in the focus group session (66%). Focus group participants (35%) expressed the
most satisfaction with viewing videos that addressed user-specific barriers to medication
adherence. Younger participants (45.3 ± 9.7 vs. 54.2 ± 22) were more satisfied with using dose
and refill reminder text messages than older participants, whereas older participants (56.0 ± 8
vs. 49.9 ± 24) were more satisfied with reading about their medications (e.g., drug interactions)
than younger participants.
Patients were satisfied with Diabetes MAP overall, and satisfaction with the site’s features
varied by age and duration of diabetes. These findings are limited by our mixed methods
approach, specific population, and single website. Satisfaction with a web-delivered diabetes
intervention is audience dependent, and user age and diabetes duration may be important
predictors of website satisfaction among adults with diabetes.
Abstract
31
Helicobacter pylori strains from high and low risk cancer regions of Colombia do not
differentially induce nitric oxide production from RAW 264.7 cells
Won Seok Shin (Eastern Virginia Medical School), Dana M. Hardbower, Keith T. Wilson,
Vanderbilt University Medical Center
Helicobacter pylori is a Gram negative, microaerophilic bacterium that infects an estimated 50%
of the global population. H. pylori infection is known to be the principal risk factor for gastric
cancer, the third leading cause of cancer-related deaths. H. pylori is able to evade the host
immune system and persist over the lifetime of the host. It indirectly attenuates nitric oxide (NO)
production, by the enzyme inducible nitric oxide synthase (iNOS), such that effective clearance
of pathogen is thwarted. Epidemiological studies have shown that two distinct geographical
regions in Colombia exhibit vastly different gastric cancer prevalences. Individuals from the high
risk region of Colombia are typically infected with more highly virulent strains of H. pylori than
individuals in the low risk regions. We chose one prototypical strain from the low and high risk
regions, termed 5009 and 5056 respectively, for our studies. Our lab has previously
demonstrated that 5056, the high risk strain, induces more DNA damage in infected cells than
5009, the low risk strain. Since H. pylori-mediated gastric carcinogenesis requires both DNA
damage and chronic inflammation, we hypothesize that 5009 and 5056 also differ in their ability
to induce NO production. To test this hypothesis, we infected RAW 264.7 cells, a murine,
macrophage cell line with 5009, 5056 and PMSS1, a laboratory reference strain, for 6 or 24 h.
Experiments were performed with and without the use of Transwell filter supports in order to
assess the affects of both direct contact between the bacterium and the cell and the effect of
soluble H. pylori-produced factors. We assessed iNOS mRNA expression using quantitative
real-time PCR after 6 h, and measured NO production using a Griess Assay after 24 h. When
the RAW 264.7 cells and the H. pylori strains were in direct contact, no significant differences in
iNOS mRNA expression and NO production were observed. Infection with 5009 resulted in a
702-fold increase in iNOS expression, while 5056 led to similar levels of iNOS expression with a
725-fold increase (n=1) in iNOS expression. 5009 induced 11.41 ± 3.043 mM NO2-, while 5056
induced 16.35 ± 1.891 mM NO2- (n = 3). Likewise, both strains induced similar levels of iNOS
expression and NO production when separated from the cells by Transwell filter supports.
Infection with 5009 induced 388.1 ± 151.1-fold increase in iNOS expression (n = 4). Similarly,
infection with 5056 induced 355.4 ± 175.7-fold increase in iNOS expression (n = 4). RAW 264.7
cells infected with 5009 and 5056 produced 8.040 ± 5.791 mM NO2- and 9.654 ± 6.109 mM NO2(n = 3), respectively. Again, no significant differences were observed in iNOS mRNA expression
and NO production after infection with 5009 and 5056. These data indicate that the high versus
low risk status of different H. pylori strains does not affect NO production by macrophages.
However, there are many other immunological functions that macrophages utilize to combat H.
pylori infection. Other parameters, such as phagocytosis, anti-microbial peptide production and
cytokine/chemokine expression should be assessed in future experiments. Strains from high
and low risk regions of Colombia may yet differentially regulate one or more of the
aforementioned macrophage functions.
Abstract
32
The Role of Hepatic Estrogen Receptor in the Regulation of Glucose Metabolism
Vanessa Roos (Medical University of South Carolina), Andrew Wolfe, Johns Hopkins University
School of Medicine
Reproductive function has long been known to be sensitive to changes in metabolic status with
states of negative energy balance associated with decreased reproductive function. It is
becoming increasingly clear that states of excess energy can also contribute to reproductive
dysfunction. Less understood is how reproductive function can influence metabolism. We
proposed that gonadal steroid hormones may directly regulate metabolic function. Since the
liver plays an essential role in regulating energy metabolism and expresses the estrogen
receptor, we hypothesized that estrogen action via the ERα (ESR1) in the liver regulates
glucose metabolism. To test this hypothesis, floxed Esr1 (flEsr1) mice, developed in our
laboratory, were injected via tail vein with a CRE expressing adeno-associated virus
(AAV8.TBG.PI.-Cre.rBG) to produce a hepatic Esr1 knock out mouse (LEsr1KO mouse).
Control mice were injected with a GFP expressing adeno-associate virus
(AAV8.TBG.PI.eGFP.WPRE-.bGH). To assess the efficacy of the injection, fluorescent
microscopy was used to observe the expression of GFP (green fluorescent protein) in the GFP
virus injected mice livers and in control CRE injected mice livers. The results demonstrated wide
spread expression of GFP with highest expression near the portal vein. Successful knockout of
Esr1 receptor in LEsr1KO mice was assessed using a TaqMan quantitative real-time PCR
assay. GAPDH expression was also measured as a reference gene. Glucose tolerance tests
were performed on LEsr1KO and control mice using a standard glucometer and levels of insulin
30 minutes post-glucose injection (GSIS) were measured using a Luminex Insulin assay.
Glucose tolerance proved to be significantly improved in male CRE injected mice but not female
CRE injected mice compared to GFP injected controls. GSIS levels were increased in both male
and female CRE injected mice compared to controls, although not significantly. These data
suggest that estrogen plays an important role in liver metabolic function and that changes in
glucose tolerance during the reproductive cycle may be due to estrogen action in the liver.
Abstract
33
Does a High Fat Diet Induce an Inflammatory Response and Accelerated Amyloid
Pathology in APP/PS1 Mice?
Casey L Freeman1, Fiona E Harrison2, Jennifer M Walker2;
1
University of Kansas School of Medicine
2
Division of Diabetes, Endocrinology & Metabolism, Vanderbilt University Medical Center
Obesity has been linked to many chronic diseases; however, the molecular mechanisms of
obesity and many of its metabolic consequences are complex and not well understood. Our
research investigates the effects of a high fat diet on expression of a number of genes relating
to inflammatory response and amyloid neuropathology in a mouse model of Alzheimer’s disease.
Our hypothesis is that obesity drives inflammatory response and oxidative stress in the brain,
and that these changes will be magnified in the brains of APP/PS1 mice. Wild-type and
APP/PS1 littermates were maintained on a high fat diet (HFD: 60% fat from lard) or a low fat
diet (LFD: 10% fat from lard) starting at 8 weeks of age. At 8 months of age, a glucose tolerance
test was performed and the mice were sacrificed. Specific brain areas (cortex, hippocampus)
were excised and used for qPCR for measurements of a number of genes including
inflammatory markers, insulin resistance, and Alzheimer’s neuropathology, as well as
determination of lipid peroxidation and amyloid beta. HFD led to obesity in wild-type and
APP/PS1 mice, but HFD APP/PS1 mice showed significantly impaired glucose clearance as
compared to the two LFD groups and the HFD wild-type group. Gene expression for leptin,
TNFα, and INSR (insulin receptor) differed between hippocampus and cortex and indicated that
both HFD and APP/PS1 genotype modified expression, although not all trends reached
significance. More work is needed to confirm trends observed in these data, but this preliminary
study does support our hypothesis that APP/PS1 mice may be more affected by HFD, and
obesity can drive changes in hippocampal gene expression. The main limitation at this point is
in terms of group sizes. In the future, more mice will be added to each group and a diet reversal
will be performed to assess the effects on leptin, TNFα, INSR, and several other oxidative stress,
inflammatory, insulin resistance, and Alzheimer’s neuropathological markers.
Abstract
34
TcBuster transposase aggregation in kidney cells.
Laura M. Downes(University of Kentucky College of Medicine) Lauren E. Woodard, and
Matthew H. Wilson, Vanderbilt University.
Transposons, or “jumping genes”, are transposable elements used for gene therapy. We are
investigating TcBuster, a transposon/transposase system in the hAT superfamily whose
transposase tends to aggregate in a rodlet shape in kidney cell nuclei. We set up both cell-free
and HEK-293 cell assays to probe how the rodlets form over time. Through observation of timelapsed images, we found that aggregation appears to occur additively at both rodlet ends, that
the rodlets are very mobile within the cell nucleus, and that the rodlets also tend to clump with
other rodlets within the nucleus to create larger structures. From our cell free assay we
conclude that in the presence of DNA transposon, the transposase tends to aggregate with the
DNA into structures similar to the octameric structure found to form by the hAT transposase
Hermes. The polymerized TcBuster transposase appears to be seeded to the surface by the
octameric DNA transposase. Our findings suggest that rodlet formation is a visible sign of
overproduction inhibition, which is when the transposase fails to transpose when present at a
high concentration. Most transposases are subject to overproduction inhibition so it is important
to obtain a better understanding of this phenomenon for gene transfer success.
Abstract
35
In vitro interferon regulatory factor 3 (IRF3) regulation of thermogenesis.
Sophie Leung (Geisel School of Medicine at Dartmouth), Manju Kumari, Evan Rosen, Beth
Israel Deaconess Medical Center
Regulators of thermogenesis are sought after therapeutic targets for the treatment of type 2
diabetes and obesity due to their potential to increase energy expenditure and decrease
adiposity. In preliminary studies in IRF3 knock out mice, we observed increases in energy
expenditure, brown adipose tissue, cold tolerance, and thermogenic gene expression. Further,
in wild type mice we observed hypophosphorylation of IRF3 (which is inhibitory) at S135 after
cold exposure. These together suggest that IRF3 is a negative regulator of thermogenesis. To
further characterize IRF3’s regulatory role, we created two IRF3 mutants containing a S171A or
S135A substitution thereby eliminating an activational phosphorylation site. In future studies we
will overexpress these mutants separately in murine adipocyte and pre-adipocyte cell lines and
stromal vascular cells to determine the effect on Ucp1, Pgc1α, and Prdm16 transcription upon
cold exposure. In light of our preliminary data, we expect that the mutations will have a
disinhibitory effect leading to upregulation of thermogenic gene expression.
Abstract
36
Mitochondrial DNA haplogroup is associated with cellular oxidant production and
mitochondrial DNA damage.
Terrence T. Jones (University of Tennessee Health Science Center), Jamelle A. Brown, Tanja
Dudenbostel, David A. Calhoun and Scott W. Ballinger, University Alabama at Birmingham
Diabetes affects 29.1 million people or 9.3% of the U.S. population. Interestingly, AfricanAmericans and Hispanics have an increased susceptibility to type-2 diabetes than Caucasian
Americans; the mechanisms underlying this disparity are not known. One factor often
overlooked is the contribution of mitochondrial genetics to disease susceptibility. Mitochondria
are both sources and targets of oxidative stress, which has been shown to contribute to
endothelial dysfunction and diabetes. Mitochondrial DNA (mtDNA) damage has also been
associated with diabetes. We hypothesize that cells harboring different mitochondrial
haplogroups will produce different amounts of oxidants under conditions of stress and will
accumulate different levels of mitochondrial DNA damage. Overall these processes may result
in differential susceptibility to type-2 diabetes. In this light, we hypothesized that cells with
African mtDNA haplogroups (e.g. haplogroup “L”) will generate more oxidants and have more
mtDNA damage than those with northern European origins.
To test this, human umbilical vein endothelial cells (HUVECs) and lymphocytes from healthy
adult controls were haplogrouped, and separated into African or Eurasian cohorts based on
restriction fragment length polymorphism (RFLP) analysis of mtDNA PCR products. HUVECs
were treated with TNFα, a proinflammatory cytokine that mediates mitochondrial oxidant
production, and stained with dihydrorhodamine 123 to observe oxidant production. Basal
mtDNA damage was also assessed in both HUVECs and healthy adult lymphocytes. Results
show that HUVECs with African mtDNAs generated more oxidants when treated with TNFα
compared to HUVECs harboring Eurasian mtDNAs; this oxidant generation also co-localized
with mitochondria, suggesting mitochondrial origin. Finally, both HUVEC and lymphocytes
having African haplogroup mtDNAs displayed increased mtDNA damage compared to those
carrying Eurasian mtDNAs. Consequently, increased basal expression of oxidants and mtDNA
damage associated with mtDNA haplogroup may explain the differential susceptibility to
diabetes.
Abstract
37
rpL13a SnoRNAs Mediate Lipotoxicity in Diabetic Cardiomyopathy
Elizabeth K. Asfaw (Charles R. Drew University/David Geffen School of Medicine at UCLA),
Chris Holley, Jiyeon Lee, and Jean Schaffer
Washington University in St. Louis School of Medicine, St. Louis, MO
Introduction: Diabetic patients have an increased risk of heart failure. Pathologically, failing
hearts from diabetic patients are characterized by steatosis that is thought to contribute to
cardiomyocyte cell death and dysfunction. To model this metabolic cardiomyopathy, the MHCACS (ACS+) mouse was generated by cardiomyocyte overexpression of long-chain acyl-CoA
synthetase, which leads to heart failure through lipid-induced oxidative stress and inflammation.
Small nucleolar RNAs (snoRNAs) from the rpL13a locus have been shown to be important
mediators of lipotoxic and oxidative stress in cell culture models. Mice with loss of function of
the rpL13a snoRNAs (sno-/-) have recently been generated to study the in vivo role of these
non-coding RNAs, and this model has normal heart function.
Methods: To determine if rpL13a snoRNAs mediate cellular damage and contribute to
cardiomyopathy in the MHC-ACS cardiomyopathy model, ACS+ and sno-/- mice were crossed.
Heart function, gene expression, and histology were assessed in the progeny (ACS+/sno-/-).
Results: In ACS+ mice, left ventricular hypertrophy and heart failure are detected as early as 6
weeks of age. Echocardiographic analysis showed left ventricular mass was decreased in the
ACS+/sno-/- mice compared to the ACS+ mice at both the 6 and 8-week time points. Fractional
shortening in the ACS+/sno-/- mice was also increased compared to the ACS+ mice, suggesting a
significant improvement in left ventricular systolic function. To examine mechanisms underlying
improved cardiac function in the ACS+/sno-/- mice, gene expression was analyzed for markers of
inflammation, heart failure and fibrosis. Cytokines and cellular markers of inflammation were
induced in the ACS+ mice at 6 and 8 weeks. A similar pattern was observed ACS+/sno-/- mice,
although IL-6 was decreased compared to the ACS+ mice. Compared to ACS+ mice, ANP levels
were significantly reduced in both 6 and 8-week ACS+/sno-/- mice, consistent with a decrease in
heart failure. Markers of fibrosis (Col1A1, Col3A, CTGF) were induced in ACS+ and ACS+/sno-/mice at similar levels at 6 and 8 weeks. Trichrome staining of formalin-fixed samples revealed
no evidence of fibrosis at 6 weeks in ACS+ and ACS+/sno-/- mice (8 week studies pending).
Enlarged cardiomyocytes and mononuclear infiltrates were observed and in both ACS+ and
ACS+/sno-/- mice.
Conclusion: Loss of function of rpL13a snoRNAs improves cardiomyopathy in the MHC-ACS
mouse model of metabolic cardiomyopathy. Given similar markers of inflammation in ACS+ and
ACS+/sno-/-, it appears that the rpL13a snoRNAs act downstream of lipid induced inflammation
in this model.
Abstract
38
HDL-mediated eNOS activation falls before the onset of T2DM in obese non-human
primates
Erica Couzens (Loma Linda University), Francis Kim, University of Washington
One of the protective actions of HDL is to stimulate the production of NO in endothelial cells via
eNOS phosphorylation and activation. In T2DM we found that there is decreased HDLmediated eNOS activity. Decreased eNOS has been proposed to increase risk for the
development of T2DM. We hypothesized that HDL-mediated eNOS activation is impaired prior
to the onset of T2DM during obesity. Evidence for this was seen in a group of non-human
primates on a high fat diet for 24 months that became obese and subsequently developed
insulin resistance and T2DM. We utilized blood samples at baseline, 4, 8, 12, 18, and 24
months, isolated the HDL, and completed a cell-based assay in which HDL was incubated with
endothelial cells, and eNOS phosphorylation, which is a marker of eNOS activity, was measured
by in-cell western. In high fat fed primates, eNOS activity fell by 31% (p=0.0025) after 4 months
and remained decreased between 4-24 months. At the end of 24 months, obese primates that
underwent roux-en-y gastric bypass showed a 16% increase (p=0.1765) in eNOS activity.
These data indicate that HDL-mediated eNOS activation falls prior to the onset of T2DM and
may be altered following bariatric surgery. Proteomic experiments are ongoing to determine the
changes in HDL proteins and lipids that may cause decreased eNOS activity.
Abstract
39
Influence of Glucose Setpoint and Pre-Meal Bolus on PID-Based Closed-Loop System
Performance
Casey Card (National University of Ireland, Galway), Jennifer L Sherr, Eda Cengiz, Camille I
Michaud, Neha Patel, Miladys M Palau-Collazo, Lori Carria, Eileen Tichy, William V Tamborlane,
Stuart A Weinzimer, Yale University
Closed-loop (CL) artificial pancreas systems combine insulin pump and continuous glucose
monitor (CGM) technologies to control blood glucose (BG) levels automatically without human
intervention. Proportional-Integral-Derivative (PID)-based computer controller algorithms
employed in the design of such systems determine the appropriate insulin doses in response to
BG levels and BG rate of change. The optimal glucose setpoint and need for manual pre-meal
insulin boluses to optimize such a system have not been established. We analyzed blood
glucose profiles from five closed-loop protocols utilizing a PID controller with insulin feedback to
explore these questions. Data for 41 subjects (23 female, age 19±4y, A1c 7.3±0.7%) were
analyzed to assess the effect of glucose setpoint (100mg/dl, [G100] vs 120mg/dl [G120]) and use
of 0.05-0.08 u/kg pre-meal insulin bolus (PMB+ or PMB-) on CL system performance. Mean
blood glucose (BG); BG levels within (70-180mg/dL), below (<70mg/dL), or above (>180mg/dL)
target range, prandial BG excursion and prandial BGAUC; and hypo- (BG<60mg/dL) and
hyperglycemia (BG>250mg/dL) were calculated for each condition. Compared to 30 G120
subjects, 11 G100 subjects had a significantly lower average BG (132±33mg/dL vs 146±33mg/dL,
p<0.01); spent significantly more time in target range (83.8±9.8%, vs 74.9±10.5%, p<0.02) and
less time above target range (13.0±9.6% vs 23.7±11.4%, p<0.01), with no significant increase in
time <70mg/dL (3.2±3.5% vs 1.4±2.4%, p=0.07) or <60 mg/dL (1.1% vs 0.3%, p=0.11). 15
PMB+ subjects had smaller prandial BG excursion and BGAUC than 26 PMB- subjects (94 vs
105mg/dL and 207.4 vs 254.2mg*hr/dL, respectively), but these differences only reached
statistical significance post-lunch (64±8 vs 102±7mg/dL, p<0.01 and 112±20 vs 225±29mg/dL,
p<0.01, respectively). Using a sensor glucose setpoint of 100mg/dL rather than 120mg/dL in a
PID-based CL system results in a lower average BG and improved time in target range, without
a significant increase in hypoglycemia. The use of a small pre-meal bolus did not equivocally
demonstrate benefit in mitigating prandial glycemic excursions; larger boluses or other
strategies will likely be necessary to minimize post-prandial glucose levels.
Abstract
40
Interleukin 17A induces renal proximal tubule NHE3 expression in hypertension
Linjue Zhu (Medical College of Georgia – Georgia Regents University), Allison Norlander,
Meena Madhur, Dave Harrison, Vanderbilt University School of Medicine
T cells are essential to the development of Angiotension II (Ang II) induced hypertension.
Specifically, the TH17 class of CD4+ T Helper cells produces a unique cytokine Interleukin 17
(IL17) that when knocked out in mice, confers the mice a 20mmHg a reduction in blood
pressure following Ang II treatment as compared to controls by day 21. We hypothesized that
IL17 increases the activity of Sodium Hydrogen Exchanger 3 (NHE3) in the kidney proximal
tubule through intermediary SGK1 signaling to increase Na+ and water reabsorption, therefore
causing a rise in blood pressure. We used a quantitative Western method to quantify the
expression of NHE3 in human kidney proximal tubule epithelium (HK2) cells following IL17
treatment. We found that following treatment with IL17A, an isoform of the IL17 cytokine family,
NHE3 expression increased by as much as 2.5 times as compared to untreated controls. To
investigate the role of serum glucocorticoid kinase 1 (SGK1) in the IL17-NHE3 signal
transduction pathway, we treated cells with a SGK1 inhibitor as well as IL17A and subsequently
examined the NHE3 expression. We found that at 1mM concentration of SGK1 inhibitor, NHE3
expression was decreased. Altogether, these results suggest that IL17A signals through SGK1
to induce NHE3 expression in the kidney proximal tubule epithelium. These results may shed
light on a novel function of SGK1 and NHE3 in modulating blood pressure in addition to their
traditional roles in regulating epithelium sodium channels and tubular pH, respectively.
Abstract
41
Attitudes and Beliefs about Diabetes Medications and Illness Acceptance in the Rural
Black Belt
Sarah Owens (University of Alabama School of Medicine); Emily Wesson; Susan Andreae;
Monika M. Safford, MD; Division of Preventive Medicine, UASOM
The Black Belt Action Committee reported that diabetes mortality was 38.7/100,000 population,
contrasted to the US rate of 24.6/100,000 in 2007. The rate is 50% higher among Alabama’s
rural African American population compared to whites, and studies show that people living with
diabetes in this population report almost two times higher medication non-adherence than the
national average. The Chronic Illness Trajectory Model by Corbin and Strauss posits that a
feeling of wellness is achieved when there is a balance between 3 central domains: Body,
Biography, and Conception of Self (the BBC Chain). Diagnosis of chronic illness, such as
diabetes, can profoundly destabilize this BBC Chain, making it difficult for patients to accept
their illness and understand the role of medications in living healthy lifestyles long-term. To gain
insights into community members’ lived experience of diabetes and barriers to acceptance of
illness and medication adherence, we conducted focus groups in Alabama’s low income Black
Belt area. Using modified Grounded Theory, a focus group topic guide was created, eligible
participants were recruited through respondent driven sampling, and focus groups were
moderated, transcribed, and analyzed using Nvivo 10 software and open coding. Common
themes were revealed throughout these focus groups, which will help inform the development of
a peer support program that aims to improve diabetes medication adherence and health
outcomes using peer storytelling and diabetes education. Major themes included: 1) low
knowledge and misperceptions of both diabetes as a disease entity and the efficacy of diabetes
medication; 2) disease acceptance and resolve to take medications triggered by a physical
exacerbation of the participants’ body symptoms and occurrence of diabetes complications; 3)
improved medication adherence with the realization that pharmacologics were a vital link to
maintaining a participants’ sense of biography and conception of self by preserving body
functions that could not be maintained through self-management behaviors (e.g., diet and
exercise) alone; and 4) the physical complications of diabetes manifestations in close family and
friends often served as the emotional impetus to participants’ disease acceptance and
motivation to take medications. Further focus groups will be conducted until no new themes
emerge and saturation is reached. Education to address diabetes and medication
misperceptions as well as focused storytelling addressing these themes will be integrated into
the intervention arm of the study.
Abstract
42
Human Islet Cells Replicate and Transdifferentiate in Response to Hyperglycemia in an
Islet Transplant Mouse Model
Zachary Fowler (University of North Dakota), Xiaojuan Chen, Columbia University
Pancreatic islet cell replication and transdifferentiation are potential mechanisms through which
beta cell mass that is lost in the diabetic state can be restored. The factors that stimulate these
processes in human islets are not well understood. To test the hypothesis that human islet cells
can replicate and transdifferentiate in response to glucose, isolated human islets from deceased
donors were transplanted under the kidney capsule of immune-deficient mice. Streptozotocin
was administered to induce hyperglycemia, and islet graft sections taken three and eight days
post hyperglycemia-induction were examined by immunofluorescence. BrdU and Ki67 were
used as markers of proliferation and were readily detectable in both alpha and beta cells
exposed to hyperglycemic conditions, while the islets under normoglycemic conditions had
minute positive staining for these markers. The highest levels of beta cell proliferation were
seen after three days of hyperglycemia. Additionally, hyperglycemia induced a colocalization of
insulin and glucagon, suggesting that glucose is a stimulus for lineage reprogramming in
pancreatic endocrine cells. In conclusion, using immunohistochemistry, we observed the
occurrence of both replication and transdifferentiation in human islets under hyperglycemia.
Both of these phenomena have important implications for beta cell regeneration in patients with
type I diabetes and some forms of type II diabetes, as well as improving islet mass in patients
with type I diabetes undergoing treatment with islet transplantation.
Abstract
43
Bile diversion to the distal intestine achieves weight loss and metabolic improvements
similar to Roux-en-Y gastric bypass.
Steven Cai (Chicago Medical School), Robb Flynn (Department of Surgery, Vanderbilt
University), Naji Abumrad (Department of Surgery, Vanderbilt University)
Bariatric surgery, specifically Roux-en-Y gastric bypass (RYGB), achieves durable weight loss
and imparts both immediate and long-term metabolic improvements by mechanisms that are not
entirely understood. We investigated in diet-induced obese (DIO) mice the specific role of
increased circulating bile acids (BA) frequently observed after RYGB using a novel surgical
procedure where gallbladder (GB) bile was diverted to the duodenum (GB-D, sham surgery),
the jejunum (GB-J) or ileum (GB-IL) and compared metabolic outcomes to RYGB mice. Mice
receiving GB-IL lost more body weight, preferentially through fat mass, than GB-D or GB-J mice
and even surpassed weight loss in RYGB mice. GB-IL mice also sustained improvements in
glycemic control and hepatic steatosis that was comparable to RYGB mice. Circulating bile
acids, specifically tauro-β-muricholic acid (TβMCA), were increased in GB-IL but not RYGB
mice. Increased TβMCA, a known FXR antagonist, was concurrent with decreased BA receptor
(FXR) expression in the liver and increased TGR5 and GLP-1 expression in the ileum. These
results suggest that altered enterohepatic circulation of BA contributes to metabolic
improvements seen in bariatric procedures such as RYGB. The GB-IL procedure, a technically
simpler procedure, may serve as a potential therapeutic in treating obesity.
Abstract
44
Influence of Childbearing on Women with Type 1 Diabetes: The 50 Year Medalists
Heather Love, MPH, Tufts University School of Medicine, Liane J. Tinsley, MPH, Jennifer Sun,
MD MPH, Stephanie D’Eon, MS ATC, Stephanie Hastings, BA, George King, MD, Hillary
Keenan, PhD, Joslin Diabetes Center, Boston MA
Pregnancy is a documented independent risk factor for progression of pre-existing diabetic
retinopathy (DR), nephropathy (DN) and cardiovascular disease (CVD). Throughout pregnancy,
hormonal readjustments in maternal endocrine tissues alter glucose tolerance, and increased
cardiovascular demands result in vascular changes and potential preeclampsia. In the early
days of type 1 diabetes treatment, women were discouraged from getting pregnant and having
children due to these potential complications. This analysis examines long term influence of
childbearing on women with 50 or more years of type 1 diabetes (T1D) duration in female
participants of the Joslin 50-Year Medalist Study, a cross-sectional study collecting clinical, selfreport and laboratory data (n=465). These women have an average age of 64±7.1 years, T1D
duration 54.5±5.3 years, duration at time of pregnancy 13.8±7.6 years and year of first
pregnancy of 1971 [1966, 1977]. A significance was found in A1c (7.4±1.1% v. 7.2±0.9%,
p<0.01), waist to hip risk ratio (WHR) (66% v. 81% p<0.01), antihyperlipidemic medication use
(58.9% v. 74.9% p=0.02) , HDL (69.8±20.6 mg/dL v. 73.2±18.8 mg/dL p=0.04), LDL (85.3±20.6
mg/dL v. 79.89±18.8 mg/dL p<0.01), c-reactive protein (2.7±4.8 mg/dL v. 1.1±2.4 mg/dL,
p=0.03) and body mass index (24.5±4.7 kg/m2 v. 25.5±4.8 kg/m2, p=0.04) between non
childbearing and childbearing groups. No significant difference was seen in the prevalence of
DR (59% v. 41%, p=0.9), DN (15.3% v 10.8%, p=0.2) or CVD (34.0% v. 29.8% p=0.4) between
groups. Interestingly, there was a difference in the prevalence of self-reported cardiovascular
disease by births (1: 21.9%, 2: 26.2%, 3: 53.3%, 4: 50.0%, p=0.02).This was not explained by a
difference in duration (p=0.12), HbA1c (p=0.7), DN (p=0.1), c-peptide (p=0.7), antihypertensive
medication use (p=0.9), antihyperlipidemic medication use (p=0.08), HDL (p=0.2), WHR (p=0.8),
GAD65 (p=0.7), or IA2 autoantibodies (p=0.4). Although vascular endpoints did not vary
significantly between women who did and did not have children, the number of children borne
appears to influence the rate of CVD in this group, without influence from traditional diabetes
related CVD risk factors.
Abstract
45
Metabolic phenotypes of obesity-prone and obesity-resistant mice
Amy Y. Han (Case Western Reserve University School of Medicine), Charles Addo-Yobo,
Xiaoyan Yin, Fred Anokye-Danso, Rexford Ahima, University of Pennsylvania School of
Medicine, Philadelphia, Pennsylvania
Worldwide obesity epidemic has resulted in an increased prevalence of metabolic disorders
such as type 2 diabetes and hyperlipidemia. Both environmental factors and genetic
predispositions play significant roles in the development of obesity. Similar to humans, certain
mice strains are obesity prone while some remain obesity resistant when fed on similar high fat
diets. We studied obesity prone C57Bl/6J mice and obesity resistant SWR/J mice in pre-obese
states for differences in their energy homeostasis. Male C57BL/6J mice and SWR/J mice,
(Jackson Laboratory, Bar Harbor, Maine), age 10 weeks, were housed in 12 hour light-dark
cycles (lights on at 7 am) with free access to chow and water. After one week adjustment
period, body composition was measured with 1H-MRS, and energy homeostasis was assessed
with Comprehensive Laboratory Animal Monitoring System (CLAMS). Thermal imaging as well
as changes in energy expenditure in response to β3-adrenergic agonist treatment were
assessed. Lastly, glucose homeostasis was measured using glucose tolerance test. Data
analysis showed that the C57Bl/6J mice weighed significantly more than the SWR/J mice
despite similar food intake. Both strains demonstrated nocturnal increases in food intake,
oxygen consumption, respiratory exchange ratio (RER), and locomotor activity. SWR/J mice
demonstrated lower RER, but higher energy expenditure during the light phase indicating an
increase in fat oxidation. In addition, SWR/J mice showed greater energy expenditure in
response to β3-adrenergic agonist treatment and more glucose tolerant than C57Bl/6J mice. In
conclusion, the obesity resistant genetic background of SWR/J mice may be associated with
enhanced fat oxidation, thermogenesis, and glucose homeostasis
Abstract
46
The Clinical and Biochemical Characterization of Pancreatic Diabetes
James Lyons (UAB School of Medicine), Fernando Ovalle MD, UAB
Pancreatic diabetes is a phenotype of diabetes mellitus that is caused by pancreatic destruction.
Disorders that lead to this condition include, among others: chronic pancreatitis, cystic fibrosis
and pancreatectomy. Presently, this disease has not been well characterized and we believe
that by analyzing the data of patients with pancreatic diabetes we will discover distinct
parameters that will aid in the diagnosis of the disorder and will help clinicians distinguish it from
other types of diabetes, most importantly types 1 and 2 diabetes. The data of 1257 consecutive
patients from their first visit to a tertiary care center diabetes specialty clinic was recorded and
the date from 27 patients who were diagnosed with pancreatic diabetes was compared to that
from a matched group of patients diagnosed with type 1 and type 2 diabetes. The type 1 and 2
patients used for comparison were matched based on gender, race, and duration of diabetes.
The results show that patients with pancreatic diabetes have similar BMI, systolic blood
pressure, diastolic blood pressure, and HDL levels to those with type 1 diabetes, while their
triglyceride levels were similar to patients with type 2 diabetes. C-peptide levels were distinct in
patients with pancreatic diabetes and islet cell autoantibodies were frequently present in
patients with pancreatic diabetes probably representing an epiphenomenon. These novel
findings could help clinicians avoid making a wrong diagnosis of autoimmune diabetes in these
patients.
Abstract
47
Insulin Use and Long-Term Weight Change in U.S. Adults with Type 2 Diabetes Mellitus:
Analysis of NHANES 2009-2012
Christopher Moutos (University of Arkansas for Medical Sciences), Hsin-Chieh “Jessica” Yeh,
and Nisa Maruthur, Johns Hopkins University School of Medicine
Standard treatment for achieving glycemic control in type 2 diabetes mellitus is to begin with
lifestyle modification. If an optimal glycemic target is not achieved, oral antidiabetic medications
are used, followed by insulin therapy if necessary. After initiating insulin therapy, patients tend to
gain weight, which exacerbates the already fading insulin sensitivity of these individuals. This
can lead to a greater need for insulin and potentially more weight gain over time. However, few
data are available on long-term weight change after insulin initiation. We used the National
Health and Nutrition Examination Survey (NHANES) to explore how different stages of type 2
diabetes treatment relate to weight change. Using this nationally representative sample, we
characterized insulin use in adults with type 2 diabetes and to determine the association
between duration of insulin use and body mass index (BMI). In survey years 2009-2012, we
identified 1286 individuals who were diagnosed with diabetes at age 30 or older with available
BMI data. These individuals were divided into five groups based on the type of diabetes
treatment they received: (1) no treatment (2) oral antidiabetic treatment only (3) insulin use ≤ 1
year (4) insulin use 1-5 years (5) insulin use > 5 years. The age of the individuals
characterized showed an overall upward trend from a mean of 58.6 years in the non-treated
group, to a peak of 65.9 years in those having been on insulin for > 5 years. Similarly, the
lowest values for duration of disease and mean HbA1c levels were both seen in the non-treated
group (6.2 years and HbA1c =6.7%), with the highest values in patients treated with insulin for >
5 years (19.2 years and HbA1c = 8.2%). The trend in gender followed that in patients not
currently on treatment, the majority (57.4%) were female, while in patients who had been on
insulin > 5 years, the majority (56.9%) were male. After adjusting for current age, gender, and
race, compared to patients without medications, individuals on oral medication and insulin had a
higher BMI (adjusted beta-coefficients (95% CIs) of BMI for oral meds only, insulin use ≤1 yr,
insulin use 1-5 yrs, and insulin use >5 yrs: 2.4 (0.9-4.0), 2.7 (0.2-5.3), 4.7 (1.4-8.1)and 3.0 (1.15.0), respectively) . In all, these results indicate that weight gain after initiation of insulin therapy
may not be a transient event. Instead, this increase in weight may continue even up to 5 years
after beginning insulin.
Abstract
48
The Impact of Peripheral Artery Disease on Skeletal Muscle Gene Expression
Alejandro Silva1, Katelyn Hughes2, Alison Burkart2, 3, Jonathan Dreyfuss2, Mark Creager3,4, and
Mary-Elizabeth Patti2.4
1
Rutgers NJMS, 2Joslin Diabetes Center, 3Brigham and Women’s Hospital, 4Harvard Medical
School
Peripheral artery disease (PAD) is a manifestation of atherosclerosis which typically affects
arteries in the lower extremities. Arterial narrowing can lead to functional impairment with pain
and reduced ability to walk, in parallel with altered skeletal muscle metabolism. In addition, PAD
is associated with insulin resistance, limiting the uptake of glucose into skeletal muscle. To test
the hypothesis that PAD alters gene expression, we analyzed gene expression in human
skeletal muscle in patients with PAD (n=21) as compared with healthy controls (n=9) using
GeneChip® PrimeView™ Human Gene Expression microarrays. We identified differentially
expressed genes and analyzed their functional ontology, focusing on those potentially impacting
metabolic function and vascularization. 3,431 probe sets were differentially expressed in PAD vs.
control (pnom<0.05), with 1953 upregulated and 1478 downregulated. To determine if the
expression of these genes was normalized by exercise, we conducted a similar analysis
comparing sedentary PAD patients (n = 7) to PAD patients following an exercise program for 6
weeks (n = 3). 3,478 probe sets were differentially expressed in PADsedentary vs PADexercise
(pnom<0.05), with 1,611 downregulated and 1,867 upregulated in exercising PAD patients. In
both PAD vs control and PADsedentary vs PADexercise, we identified candidate genes for further
investigation, notably PLA2G16, PKM2, AK3, SFRP4, and RNASE4. These data demonstrate
gene expression patterns differ in patients with PAD, and that exercise may normalize
expression of some of these genes.
Abstract
49
Germline zebrafish AIP mutant may serve as a potent disease model for the study of
pituitary adenoma
Jennifer Li (Chicago Medical School-Rosalind Franklin University of Medicine and Science),
Ning-Ai Liu and Shlomo Melmed, Cedars-Sinai Medical Center
Pituitary Adenomas are monoclonal, benign tumors of the anterior pituitary gland. Germline
heterozygous mutations in the Aryl hydrocarbon receptor interacting protein (AIP) gene are
reportedly associated with pituitary adenomas, in particular somatotropinomas, prolactinomas,
and/or mix of both tumor types. To elucidate the role of AIP in pituitary development and tumor
formation, we investigated embryonic pituitary development in a germline zebrafish AIP (zAIP)
mutant. A nonsense mutation within exon 4 of zAIP gene was generated previously using
customized transcription activator-like effector nucleases. Heterozygous zAIP mutant zebrafish
were then crossed, and the 3-day post fertilization (dpf) zebrafish embryos (consist of wild-type,
heterozygous-, and homozygous-AIP mutants) were used to study for the differential expression
of growth hormone (GH), prolactin (PRL), and pro-opiomelanocortin (POMC, a precursor for
ACTH). Following in-situ hybridization, we examined the phenotype and identified the genotypes
of these zebrafish embryos. At 3 days post-fertilization, heterozygous-zAIP-mutant embryos
(GH expression intensity 185.63±8.82, n=24) show induced GH expression compared to wildtype (178.97±13.9, n=11) and homozygous-zAIP mutant (176.22±12.7, n=11) embryos. In
contrast, we did not find significant differences in prolactin expression between wild-type (PRL
expression intensity 195.09±8.43, n=8), heterozygous- (191.83±14.01, n=28), and homozygouszAIP mutant (194.78±8.28, n=14) embryos. Similarly we did not find significant differences in
POMC expression between the wild-type (183.20±10.41, n=15), heterozygous (184.07±9.73,
n=22), homozygous zAIP mutant (177.60±7.17, n=11) embryos. These results suggest that at
an early stage in zebrafish embryo development (3 days post-fertilization), the non-sense
mutation on exon 4 of zAIP may induce GH-producing cells in the pituitary gland to express
increased levels of GH. The results also indicate that this particular mutation does not alter
prolactin and ACTH producing cells. To validate this animal model as an accurate disease
model for pituitary adenomas (specifically for somatotropinomas), we are continuing to study
developmental stage expression of these hormones 5 and 7 days post-fertilization.
Abstract
50
Metabolic Effects of Hydroxychloroquine in Patients with Type 2 Diabetes Mellitus
Samiksha Tarun (Saint Louis University School of Medicine), C. Rachel Kilpatrick, MD, Stacy
Hurst, BSN, CDE, Janet B. McGill, MD, and Clay Semenkovich, MD, Washington University in
St. Louis, Division of Endocrinology, Metabolism and Lipid Research
Hydroxychloroquine (HCQ) is a quinolone antimalarial drug with poorly defined antiinflammatory properties that is currently used to treat rheumatologic conditions such as
rheumatoid arthritis and systemic lupus erythematosis. HCQ use has been associated with
reduced incidence of type 2 diabetes mellitus (T2DM) in non-diabetic individuals with rheumatic
conditions and prevents worsening of hyperglycemia in T2DM patients. HCQ has also been
shown to lower low density lipoprotein (LDL). However, HCQ’s metabolic effects in T2DM
patients are not clearly understood. The primary hypothesis of this study is: clinically relevant
doses of HCQ given to patients with T2DM who are taking metformin with or without other oral
antihyperglycemic drugs, will reduce insulin resistance and reduce hepatic glucose output. The
secondary hypothesis, the focus of this interim analysis, is: HCQ use in these patients will
reduce fasting plasma glucose and fasting lipids. This study is a randomized, double blind,
placebo controlled clinical trial where subjects were given either 200 mg of HCQ twice daily or
placebo for 4 weeks. Hyperinsulinemic-euglycemic clamp testing was done at baseline and after
four weeks of treatment. Unpaired and paired two-tailed T tests with equal variance were used
to determine significance of treatment. A total of 16 patients have thus far been randomized to
placebo (n=9) and HCQ (n=7). Amongst the HCQ treatment group, reductions were observed in
diastolic blood pressure (P=0.030), HbA1c (P=0.047), and LDL (P=0.039). Mean change
between baseline and follow-up clamp between HCQ and placebo group indicate trends toward
decreased fasting glucose, HbA1c, triglycerides, total cholesterol, and LDL. Thus, these interim
results suggest a possible trend toward beneficial metabolic effects of HCQ for patients with
T2DM. Future studies are warranted to further characterize metabolic effects of HCQ use in
T2DM patients.
Abstract
51
Repression of LSD1 in adult pancreatic β cells leads to hyperinsulinemia and coincident
hypoglycemia
Benjamin Cross (University of Nebraska Medical Center), Matthew Wortham, Maike Sander,
University of California, San Diego
Epigenetic influences on gene expression are determined by various histone modifications, and
methylation of histone H3 at lysine 4 (H3K4) is often indicative of an active promoter site. LSD1
(lysine-specific demethylase 1) demethylates mono- and dimethylated H3K4 (H3K4me1/2), and
thereby suppresses gene expression. LSD1 has been proven essential for metazoan
development, but its pathophysiological function in diabetes has remained essentially
uncharacterized. In this study, we used both a mouse model and adult human β islets to
determine the role of LSD1 on β cell function. In the mouse, we inactivated LSD1 in an inducible
and cell-specific manner via breeding Pdx1-CreER; LSD1fl/fl mice. After isolating β islets from
the mouse pancreas, LSD1ΔAdultβ and control islets were subjected to glucose stimulated
insulin
secretion (GSIS) assays, and insulin secretion was measured by ELISA. Additionally, adult
human β cell islets were subjected to these same assays, with LSD1 being inhibited
pharmacologically by 2µM tranylcypromine (TCP). We found that in LSD1ΔAdultβ mice, basal
insulin secretion was enhanced coincident with hypoglycemia. It was shown that these mice had
normal glucose tolerance compared to control mice, and the hypoglycemia was not due to
enhanced insulin sensitivity. Human islets showed the same increase in basal insulin secretion
upon treatment with TCP. Interestingly however, human islets from a patient with type 2
diabetes mellitus (T2D) showed no response to TCP, indicating there may be epigenetic
differences that are LSD1-independent in T2D β cells. These data suggest that LSD1 plays an
important role in suppressing the triggering pathway for insulin secretion, both in mouse and
human islets. There are obvious potential implications for diabetes, with further mechanistic
studies needed to determine specific targets of LSD1 in the β cell.
Abstract
52
Sleep Behaviors in Pseudohypoparathyroidism
Hannah Landreth (University of Oklahoma College of Medicine), Dr. Ashley Shoemaker, MD,
MSCI, Department of Pediatrics, Division of Endocrinology and Diabetes, Monroe Carell Jr.
Children’s Hospital at Vanderbilt
Background: Pseudohypoparathyroidism (PHP) is an extremely rare, heterogeneous group of
disorders. Etiology derives from a mutation in the GNAS gene, which encodes for the Gs-alpha
subunit of G protein coupled receptors, and leads to absence of downstream second
messenger effects via cAMP. Imprinting of GNAS results in two subtypes— PHP-Ia (maternally
inherited PHP with obesity and multihormone resistance) and
pseudopseudohypoparathyroidism (PPHP—paternally inherited PHP)— both of which share
features of the Albright’s Hereditary Osteodystrophy (AHO) phenotype including short stature,
brachydactyly and subcutaneous ossification. We have noted that PHP patients often complain
of sleep apnea/sleep disturbances, but this has not been evaluated systematically. Objective:
To determine the prevalence of sleep apnea and sleep behaviors in patients with PHP. We
hypothesize that patients with PHP have a higher prevalence of sleep apnea/sleep disturbances
than the general population. Methods: Twenty patients with PHP were recruited from Vanderbilt
clinics and online advertisements. A validated, self-reported sleep quality survey was
administered via REDCap (Children’s Sleep Habits Questionnaire (CSHQ) for parents of
patients 4-13 years old or the Pittsburg Sleep Quality Index (PSQI) for participants >13 years).
Normative data from healthy 4.5 year old children was used as control data for the CSHQ.
Polysomnography records were obtained if available. Results: Nine patients 4-12 years old (all
PHP-1a, age 8.9 ± 2.7 years) and 11 patients >13 years old (age 29.6 ± 11.4 years, PHP1a n=
8, PPHP n= 3) completed the study. The CSHQ total score was 2.59 ± 0.47 in the PHP-1a
group versus 2.04 ± 0.41 in controls (p= <.001 by t-test). The PSQI global score was 8.33 ±
4.30, greater than the PSQI standardized global score cutoff of 5 for disordered sleeping. The
scores were highest in the “disrupted subjective sleep quality” and “daytime dysfunction”
subcategories. Scores were not associated with age or diagnosis. Five of the pediatric patients
had polysomnography records available. Four patients were diagnosed with sleep apnea (1 with
obstructive sleep apnea (OSA), 1 with central sleep apnea (CSA) and 2 with both OSA and
CSA). All pediatric patients had undergone tonsillectomy/ adenoidectomy without resolution of
their sleep apnea. Conclusions: Patients with PHP may have a higher prevalence of sleep
apnea and sleep disturbance than the general population. This finding may be a complication of
obesity or directly attributable to PHP and further studies are needed.
Abstract
53
Effect of Real-Time Continuous Glucose Monitoring on Glucose Counterregulation in
Long Standing Type 1 Diabetes
Nina Ran (Perelman School of Medicine at the University of Pennsylvania), Amy Peleckis,
Cornelia Dalton-Bakes, Shannon O’Brien, Nora Rosenfeld, Huang-Lan Nguyen, Mark H.
Schutta, Michael R. Rickels. Institute for Diabetes, Obesity, and Metabolism at the University of
Pennsylvania Perelman School of Medicine.
Patients with long-standing type 1 diabetes are at high risk for severe hypoglycemia due to
defects in both glucose counterregulation mechanisms: intra-islet signaling and the
sympathoadrenal system. This clinical trial investigates whether avoidance of hypoglycemia –
as achieved using real-time continuous glucose monitoring (RT-CGM) – can restore glucose
counterregulation. Specifically, the study included eight participants with longstanding type 1
diabetes and severe hypoglycemia unawareness who underwent paired hyperinsulinemic (1.0
mU/kg/min) euglycemic (plasma glucose targeted to 90 mg/dl for 240 minutes) and
hypoglycemic (glucose targeted to 80 mg/dl at 60 minutes, 65 mg/dl at 120 minutes, 55 mg/dl at
180 minutes, and 45 mg/dl at 240 minutes) clamps at baseline and six months to assess
endogenous glucose production in response to insulin-induced hypoglycemia. The control group
consisted of eight aged-matched healthy participants, and baseline characteristics were
comparable between the two cohorts (average age of 43-44 years, BMI of 25-26 kg/m2; four
males in each group). At six months, participants on RT-CGM experienced statistically
significant improvements in Clarke score (from 5.8 to 4.5; p<0.05) and Hypoglycemia Score
(from 1,952 to 714; p<0.05). A glucagon response was not detected; however we observed a
significant difference in glucagon secretion between the six-month eu- and hypoglycemic
clamps (p<0.05) that only trended toward significance at baseline (p = 0.07). Participants
exhibited a trend for increased endogenous glucose production during the final hour of
hypoglycemia at six months (p = 0.08); furthermore, we observed a difference in glucose
production between the six-month eu- and hypoglycemic clamps (p< 0.05) that was absent at
baseline. Lastly, participants experienced an increase in free fatty acids in response to
hypoglycemia at six months (p<0.05); however, no change was detected in pancreatic
polypeptide. These results suggest a minor effect of RT-CGM on glucose counterregulation,
which may be further elucidated in the 18-month data.
Abstract
54
Genetics and the Brain: A Preliminary Investigation into GLUL
Hope Jin (New York Medical College), Gail Musen, Alessandro Doria, Richie Huynh, Joslin
Diabetes Center
Many studies have shown both poorer cognitive functioning and structural brain differences in
individuals with diabetes and increased cardiovascular disease risk, though the mechanisms
underlying these conditions are unclear. Recently, a single-nucleotide polymorphism
(rs10911021) was shown to be significantly associated with coronary heart disease (CHD) in
patients with type 2 diabetes. This SNP was linked to decreased glutamine synthase expression
and altered levels of γ-glutamyl cycle intermediates, suggesting a relationship to vascular health.
To conduct a preliminary study into whether the C risk allele at rs10911021 was related to
changes in brain function and structure in diabetic individuals, an existing dataset of brain
function, structure, and cognition for type 2 diabetic subjects and controls was analyzed.
Previously collected research subject samples were genotyped by the Joslin DERC Genetics
Core. Cognitive test data and brain imaging data of subjects were then analyzed to look for
differences between control and diabetic individuals of C/C genotype or C/T or T/T (protective
allele) genotype. Among the dataset, there were 19 C/T and T/T control subjects, 22 C/C control
subjects, 11 C/T diabetic subjects, and 14 C/C diabetic subjects. No significant differences were
found for cognition. Significant decreased cortical thickness was seen in the middle frontal gyrus
of control subjects with the C/C risk allele genotype. This region is known to involved in working
memory and executive function, indicating a possible mechanistic link between the rs10911021
genetic variant and poorer cognition in individuals. Future studies will recruit a larger sample
size of subjects homozygous for the C/C risk allele and homozygous for the T/T protective allele
as well as utilize magnetic resonance spectroscopy to measure concentrations of glutamate and
glutamine within the brain.
Abstract
55
Is SUDOSCAN a sensitive tool for the assessment of small autonomic neuropathy in type
1 diabetes?
Nicole Nevarez (University of Michigan Medical School), Lynn Ang MD, Mamta Jaiswal PhD,
and Rodica Pop-Busui MD, PhD, University of Michigan
Cardiovascular autonomic neuropathy (CAN) is a common, prevalent, and serious complication
in both type 1 (T1DM) and type 2 (T2DM) diabetes and an independent predictor of mortality.
Sudomotor dysfunction may also appear early in the course of diabetes. The control of
cardiovascular and sudomotor function is largely regulated by the autonomic nervous system
via the small postganglionic, unmyelinated sympathetic cholinergic fibers. Currently available
methods to detect autonomic dysfunction although reliable and sensitive are too expensive,
invasive, time-consuming, or require large sample sizes. The goal of this study was to evaluate
whether the non-invasive sudomotor function testing using the SUDOSCAN (Impeto Medical;
Paris, France) is a sensitive and specific test for the diagnosis of autonomic dysfunction in
patients with diabetes. We tested this hypothesis in a cross-sectional study in subjects with
T1DM and age-matched healthy control subjects. 38 subjects with T1DM as defined by the
American Diabetes Association diagnostic criteria and 10 age-matched healthy control subjects
were enrolled and analyzed. The electrochemical skin conductance (ESC) of the hands and feet
was measured with the SUDOSCAN through reverse iontophoresis. CAN was assessed in
these subjects by evaluating the left ventricle sympathetic innervation and measuring the
retention index (RI) with positron emission tomography (PET) scans with the sympathetic
analogue [11C] meta-hydroxyephedrine (HED) and by heart rate variability (HRV) testing. In
initial analyses, mean RI was not correlated with either mean hands or mean feet ESC.
Additionally, none of the measures of HRV significantly correlated with means hands or feet
ESC with the exception of EI ratio, which only significantly correlated with mean hands ESC but
not mean feet ESC. These preliminary data suggest SUDOSCAN may not be the ideal tool for
assessing small autonomic neuropathy in type 1 diabetes. However, these findings may be
partly due to the limited number of subjects and large population studies with subgroup analysis
need to be done in order to show the effectiveness of SUDOSCAN as a method assessing
autonomic neuropathy.
Abstract
56
The Novel Angiotensin (1-7) Cleavage Product Angiotensin (1-4) Increases GlucoseStimulated Insulin Secretion and Cell Viability in Cultured Mouse Islets
Andrew Welch (Midwestern University Glendale, AZ) Breanne Barrow, Sakeneh Zraika, VA
Puget Sound Health Care System and University of Washington
Background: Type 2 diabetes is characterized by islet β-cell dysfunction. Recent studies
demonstrate a novel branch of the renin-angiotensin system in which angiotensin converting
enzyme 2 (ACE2) cleaves angiotensin I to generate the Mas receptor (MasR) agonist
angiotensin (1-7) (Ang(1-7)). Upregulation of this ACE2/Ang(1-7)/MasR axis has multiple
beneficial effects on pancreatic islets including enhanced glucose-stimulated insulin secretion
(GSIS) and increased islet cell viability. While studies have focused on Ang(1-7) as the potential
mediator of these beneficial effects, our lab has shown that peptidases present in the islet can
further cleave Ang(1-7) to angiotensin(1-4) (Ang(1-4)). It is unknown whether Ang(1-4) acts as
an agonist or antagonist of the MasR.
Aim: To determine whether Ang(1-4) increases GSIS, insulin content, and islet cell viability.
Methods: Islets were isolated from 10-week old C57BL/6J mice and cultured in the presence or
absence of 1 nM Ang(1-4). After 48-hour culture, insulin secretion in response to 2.8 mM (basal)
and 20 mM (GSIS) glucose, as well as islet insulin content were measured by ELISA (n=4). Islet
cell viability was determined using an XTT assay which measures mitochondrial dehydrogenase
activity in metabolically active cells (n=3).
Results: Islets exposed to Ang(1-4) tended to secrete more insulin in response to 20 mM
glucose compared to islets not exposed to the peptide [123.8±47.4 vs 81.7±25.3 pM/5 islets/h;
p=0.16], while basal insulin secretion remained unchanged [26.1±3.5 vs 24.5±4.5 pM/5 islets/h;
p=0.23]. This resulted in a 4.9±1.4 fold increase above the basal insulin response for Ang(1-4)
exposed islets versus 3.0±0.7 fold with no peptide [p=0.09]. Further, insulin content did not differ
between islets exposed to Ang(1-4) versus no peptide [62.9±7.0 vs 58.4±3.9 nM insulin/5 islets;
p=0.66]. However, cell viability was significantly increased by 24±9% in islets exposed to Ang(14) [p=0.03].
Conclusion: Ang(1-4) increases GSIS and islet cell viability, suggesting it could be utilized as a
novel therapeutic agent to treat β-cell dysfunction in type 2 diabetes.
Abstract
57
Effect of Adipose-specific Inhibition of BCKDH Activity on Hepatic BCAA Metabolizing
Enzymes and Adipocyte Morphology
Kaitlyn Order (Georgetown University School of Medicine) J. Lee1, A. Vijayakumar1, Y. Xu2, O.
D. Peroni1, C. J. Lynch 2, M.A. Herman1 and B.B. Kahn11Beth Israel Deaconess Medical Center
and Harvard School of Medicine, Boston, MA and 2 Penn State University College of Medicine,
Hershey, PA.
Elevated levels of circulating branched chain amino acids (BCAAs) (valine, leucine, isoleucine)
have been associated with insulin resistance in humans. In rodents, adipose tissue contributes
largely to whole body BCAA metabolism. The branched chain α-ketoacid dehydrogenase E1β
(BCKDH E1β) is the enzymatic subunit that regulates the irreversible decarboxylation step in
BCAA metabolism. Our aim was to determine whether deletion of BCKDH E1β in white adipose
tissue (WAT) is sufficient to cause insulin resistance and impair hepatic BCAA disposal. We
measured hepatic protein expression of BCAA catabolism enzymes: BCKDH complex (E2, E1α,
E1β), BCKDH Kinase, Protein Phosphatase 2Cm (PP2CM), and mitochondrial branched-chain
aminotransferase (BCATm) from control chow-fed mice, and high-fat high sucrose (HFHS)-fed
control and adipose-specific BCKDH knock-out (Ad-BCKDH-/-) mice. Additionally, adipocyte
morphology (number and size) from perigonadal and subcutaneous WAT was characterized
from these mice. HFHS-fed mice developed obesity compared to control mice, but relative fat
mass, circulating BCAA levels, and insulin resistance were not further worsened in Ad-BCKDH/- mice. Protein levels of hepatic BCAA catabolic enzymes were reduced in HFHS-fed mice, but
was not further attenuated in Ad-BCKDH-/- mice. Adipocyte size and number were not altered
by HFHS-feeding or genotype. BCKDH activity in WAT is important for whole body BCAA
metabolism, but circulating BCAA levels are not higher in Ad-BCKDH-/- on HFHS compared to
control HFHS. One explanation is that other tissues such as the liver are compensating in AdBCKDH-/- mice to regulate whole body BCAA levels. Since hepatic protein levels and
phosphorylation of BCAA catabolizing enzymes are not affected in our knockout model, muscle
will be a key target organ of focus for future experiments.
Abstract
58
Elevated Glucose Alters Epoxyeicosatrienoic Acid-related Enzymes in Human Retinal
Cells
Anjali J. Das (Rutgers New Jersey Medical School), Megan E. Capozzi (Departments of
Molecular Physiology & Biophysics), and John S. Penn (Departments of Molecular Physiology &
Biophysics, and Ophthalmology and Visual Sciences) Vanderbilt University School of Medicine,
Nashville, TN
Diabetic retinopathy (DR) is a vision-threatening complication of both type 1 and type 2 diabetes.
The mechanism by which diabetes causes these changes is largely undefined. However,
experimental evidence suggests that inflammatory cytokines and protein mediators may be
involved. Previous studies have shown that several retinal cell types, including Müller glia,
endothelial cells, and pericytes produce and/or respond to inflammatory signals under diabetesrelevant conditions. One approach to attenuate the chronic inflammation caused by diabetes
may be to increase levels of epoxyeicosatrienoic acids (EETs), an anti-inflammatory lipid
produced naturally in the body as a result of arachidonic acid metabolism by various
cytochrome P450 isoforms (CYPs). However, the benefits of EETs are limited because of their
rapid conversion to DHETs by soluble epoxide hydrolase (sEH). Particularly in diabetes, the
levels of these enzymes may be altered to accelerate the development of retinopathy. To test
this hypothesis, expression of CYP isoforms CYP2C8, CYP2C9, and CYP2J2, along with sEH
(gene name EPHX2) was assessed using qRT-PCR against the housekeeping gene β-actin
under normal glucose conditions (5.5 mM), L-glucose or mannitol (25 mM) as an osmotic control,
or elevated D-glucose (25 mM) in primary cultures of human retinal microvascular endothelial
cells (hRMECs), retinal pericytes, and Müller cells. Elevated D-glucose significantly increased
EPHX2 transcription but did not change the levels of CYPs in HRMECs. In Müller cells, elevated
glucose reduced the expression of CYP genes. This suggests that EET levels are reduced,
limiting their bioavailability, and subsequently promoting inflammatory signaling during diabetes.
In pericytes, high glucose stimulus did not change the expression of CYPs and sEH was not
expressed in quantifiable amounts. Overall, this suggests that increasing production of EETs
upstream by increasing the expression of CYPs or by preventing their conversion into DHETs
by decreasing expression/activity of sEH may hold therapeutic promise.
Abstract
59
Qualities of Diabetes Patients with Medication Adherence in Rural Alabama
Emily Wesson (University of Alabama School of Medicine); Sarah Owens; Lynn Andreae, MPH;
Susan Andreae, MPH; Monika M. Safford, MD; Division of Preventive Medicine, UASOM
Diabetes is one of the most prevalent diseases in the United States, affecting an estimated
8.3% of the U.S. population in 2010. In rural Alabama, diabetes is compounded by medication
non-adherence, which was found to be a problem in 56% of the population in these areas. One
model of chronic illness that may explain non-adherence is Corbin and Strauss’s illness
trajectory framework, which posits that disease states disrupt the balance between three
elements – body, biography, and conception of self – that, when aligned, creates a sense of well
being. In disease states such as diabetes, where the individual experiences a body failure, the
conception of self must be reconfigured. This process may be especially stressful and lead to
denial of the disease, negatively impacting optimal self-management behaviors. To understand
the influences that allowed individuals with diabetes to move past their body failure toward
achieving a balance with their new biography and conception of self, we interviewed four
individuals from rural south Alabama who reported being adherent to their medications. These
interviews revealed several common qualities among adherent participants, including both
internal and external qualities. Internal qualities noted among participants included a high level
of self efficacy and an internal locus of control. They also believed that the complications of
diabetes were severe and that they themselves were susceptible to these complications.
Adherent participants had a high belief that the medication would help to prevent diabetes
complications. With regard to external qualities, these patients had strong social support
networks and had heard about others’ experiences with diabetes. These findings reveal
attitudes and beliefs regarding diabetes and diabetes medications that may be helpful for future
interventions. Further work with non-adherent patients is needed in order to compare the
qualities of non-adherent participants to those of adherent patients found in this study.
Abstract
60
Patient Perspectives on Complications in Type 1 Diabetes
Divya Vangala, M.A. (Marshall University Joan C. Edwards School of Medicine
WV), Tara MacNeil, H.Dip.; Fernanda Lain, M.D.; Katie Weinger, Ed.D.,R.N.
Diabetes Center; Harvard Medical School, Boston, MA
Huntington,
Joslin
Successful treatment of diabetes is aimed at delaying the onset and/or slowing the
progression of severe complications while maximizing the patient’s quality of life. Dynamic
patient-provider collaboration is necessary to optimize treatment; however, there is little
evidence on which to build patient-centered approaches to the discussion of complications. The
purpose of this study was to gain a better understanding of patient concerns, feelings, and
preferences about complications across the duration of diabetes and how these influence selfmanagement. We used a qualitative survey and validated questionnaires to assess patient
perceptions about complications, diabetes self-care, and diabetes related distress. Medical
records were accessed to obtain the most recent A1c level. The sample included patients with
type 1 diabetes (n=60, 63% female, 56.4±12.5 years old, 15.6±1.7 years of education,
32.6±12.1 years duration, and HbA1c 7.6± 1.1)
Primary concerns about developing complications include the inability to do things that
were able to be done prior to having complications (80%), increased dependence on others
(70%) and premature death (53%). 73% had already been told by their health care provider that
they have at least one complication, with eye disease as the most prevalent (84%). The majority
of our sample (98%) was able to identify their emotional response to diagnosis with a
complication with fear (40%), feeling it was a “wake up call” (37%) and sadness (30%) being
common. The response to coping with complications varies; however, more than half (55%) feel
capable of minimizing complications, maintaining a positive attitude, and trying to maintain their
independence. We found no significant differences in self-reported self-care or self-reported
distress when comparing participants with an A1c <7.5% to participants with an A1c≥7.5%. 60%
would like to discuss complications with their provider shortly after diagnosis. Patient preference
on how often this conversation should occur was distributed among once or twice a year (30%),
more often (32%) and others would base it on the patient (35%).
Our findings suggest that there are common concerns about complications among
patients with type 1 diabetes; however, the responses to cope and recommendations to
providers varied. This was a cross-sectional qualitative study that encompassed people who
have long-term diabetes; future research should look at people across the various phases of
diabetes from early diagnosis to when complications dominate. Studies on the provider’s
perspective should also be done in order to develop methods to enhance patient-centered care.
Abstract
61
Increased BMI May be Associated With Increased Risk of Proliferative Diabetic
Retinopathy in Persons With Type 1 Diabetes
Christian A. Mehregan (Wayne State University School of Medicine), Taylor S. Blachley,
Thomas W. Gardner (University of Michigan Department of Ophthalmology and Visual
Sciences)
Introduction and Background: The prevalence of overweight and obesity has increased in
non-diabetic and diabetic persons over the past 20 years but the relationship of excess BMI to
retinopathy has not been examined in depth.
Hypothesis: Individuals with type 1 diabetes who are also overweight or obese are more likely
to develop diabetic retinopathy.
Methods: We conducted a retrospective study of patients with type 1 diabetes at the University
of Michigan Kellogg Eye Center. Dilated eye fundus examination results were used to determine
diabetic retinopathy status. BMI, HbA1c levels, blood pressure, serum triglycerides, and
demographics were collected.
Results: Logistic regression analysis found association between duration of diabetes and
presence of retinopathy (Odds Ratio (95%CI):1.129 (1.082-1.179); p < .0001). Logistic
regression model assessing for presence of proliferative diabetic retinopathy (PDR) found an
association between duration of diabetes and PDR: (1.139 (1.08-1.201); p < .0001) and
relationships approaching significance between BMI and PDR: (1.08 (0.992-1.177); p =.076)
and most recent HbA1c and PDR: (1.468 (0.96-2.244); p =.076). Chi-squared analysis found
significant differences in the likelihood of developing PDR in individuals with elevated BMI
(p=.033). The relative risk of developing PDR in overweight patients compared to normal weight
patients is 1.33 and 2.42 in obese patients.
Conclusion: These data suggest increasing BMI may be associated with a higher risk of
developing PDR. These findings imply that overweight and obese persons with type 1 diabetes
may require additional treatment considerations.
Abstract
62
Hepatic Nuclear Hormone Receptor Profiling in Nonalcoholic Fatty Liver Disease
Regina Matar (Michigan State University College of Human Medicine), Joel Lavine, Columbia
University
The worldwide increase in nonalcoholic fatty liver disease (NAFLD) is attributed to the rise in
obesity, insulin resistance, dyslipidemia, and hypertension. Usually nuclear hormone receptors
coordinate enzymatic cascades to regulate energy and lipid metabolism, but when this system
is disrupted, the risk for hepatic steatosis and metabolic syndrome increases. Similar to mouse
models of cachexia, we project that the human nuclear receptor profile will show variable
expression levels that will be diagnostic of the disease state. To test this hypothesis, we utilized
quantitative real-time reverse-transcription PCR (qpCR) to find an average of all 48 human
nuclear hormone receptor expression levels in about 300 hepatic biopsies with over 200 unique
individuals. Receptor hormone expression profiles were then compared amongst groups
including men to women, boys to girls, adults to children, those with more advanced NAFLD to
those with simple steatosis or normal liver, those children with type I NASH to those with type II,
and those treated to those untreated. Normalized mRNA levels for PPAR-δ were significantly
lower in patients who showed steatohepatitis (30.8 ± 1.84, N=19) in comparison to patients with
no steatosis (32.2 ± 1.68, N=21), in patients with fibrosis (30.6 ± 1.89, N=13) compared to
patients with an insignificant fibrosis status (32.0 ± 1.72, N=27), and in patients with a high
amount of lobular inflammation (30.4 ± 1.75, N=13) compared to patients with little to no lobular
inflammation (32.0 ± 1.72, N=27). RAR-β and FXR-α had normalized expression levels that
were significantly reduced in patients with steatosis >33% (28.7 ± 1.36, N=18) and (21.2 ± 0.99,
N=18) compared to patients with steatosis ≤33% (30.2 ± 2.14, N=22) and (22.1 ± 1.25, N=22),
respectively. Normalized mRNA levels for VDR were lower in patients with fibrosis (31.4 ± 2.17,
N=13) in comparison to patients with insignificant fibrosis (51.5 ± 42.0, N=27). Nuclear hormone
receptor expression profiles were also reduced in patients who had severe lobular inflammation
compared to patients with low to no lobular inflammation; this included (33.0 ± 1.42, N=13)
compared to (44.7 ± 24.8, N=27) in PR, (30.4 ± 1.75, N=13) compared to (32.0 ± 1.72, N=27) in
PPAR-γ, and (26.8 ± 1.71) compared to (29.8 ± 3.33) in PPAR-γ2. These findings suggest that
disruption of certain nuclear hormone receptors expression levels is correlated with the
pathological progression of NAFLD. These observations allow for diagnostic and/or prognostic
signatures regarding forms of human fatty liver disease.
Abstract
63
High prevalence of type 2 diabetes mellitus exists in resistant hypertensive patients with
primary aldosteronism.
Mingchun Liu (University of Alabama School of Medicine), Timothy Wang, Bin Zhang PhD,
Peng Li PhD, Tanja Dudenbostel MD, Suzanne Oparil MD, University of Alabama at
Birmingham (UAB)
Resistant hypertension (RHTN) is uncontrolled blood pressure (BP>140/90 mmHg) on 3
different antihypertensive drug classes. A subset of RHTN patients may have primary
aldosteronism (PA), defined as aldosterone-renin ratio (ARR)>30 or 24-h urinary aldosterone
(UAldo)>12 mcg/24hr. Previous work has shown that aldosterone stimulates insulin resistance.
This led us to hypothesize that PA patients have a higher prevalence of type 2 diabetes mellitus
(T2DM). To test our hypothesis, we retrospectively analyzed the EMR of RHTN patients who
had been worked-up for PA. Patients taking spironolactone, have end-stage renal disease
(ESRD), or had incomplete urine collections were excluded. Those included in the analysis
(n=2043) were categorized into two groups, PA (n=442) and non-PA (n=1601). Prevalence of
T2DM was assessed for both groups if they meet one of the following criteria: 1) previous
diagnosis or current anti-diabetic medication(s), 2) fasting glucose≥126 or, 3) HbA1C≥6.5.
Statistical analysis revealed that PA patients have a significantly higher prevalence of T2DM
than non-PA patients (22.1% vs. 15.4%, p=0.0001). Therefore, PA may be a predictor of T2DM
risk in patients with RHTN. This clinical study provides a basis for further exploration into how
these disease processes interact. Ultimately, it may help in the development of more effective
therapeutic treatments for targeting these chronic conditions.
Abstract
64
A role for Retinoic Acid Signaling in Macrophage Phenotypic Switching During Acute
Kidney Injury
Radostin Penchev, George Washington University School of Medicine, Takuto Chiba, Nataliya
Skrypnyk MD, and Mark de Caestecker M.B., B.S., Ph.D, Vanderbilt University Medical Center
Acute Kidney Injury (AKI) is characterized by sudden and rapid decline in GFR from baseline
that is independently associated with increased risk of death and an in-hospital mortality rate of
40-50%. During the early stages of AKI pronounced hypoxia triggers the activation and
infiltration of proinflammatory M1 macrophages and further tissue damage. With time, the
adaptive immune system is mobilized and M2 macrophages promote tissue repair and
downregulate the acute M1 response that is damaging to the kidney. Preliminary studies in our
lab have shown that inhibition of Retinoic Acid (RA) Signaling with the antagonist BMS-493
exacerbates kidney injury and leads to downregulation of M2 and upregulation of M1
macrophage markers. We therefore hypothesized that RA signaling regulates macrophage
phenotypic switching after AKI. To address this we first utilized an ischemia and reperfusion
mouse model of acute kidney injury where we detected gradual increase in the level of the RA
producing enzyme RALDH3 within the interstitium of the outer medulla at 6 hours, 12 hours and
24 hours after injury followed by a gradual decrease from day 3 to day 7 after injury whereas
Raldh3 was virtually absent in uninjured control. Using a RARE-LacZ reporter mouse, a LacZ
reporter line for RA signaling activation, we observed active RA signaling response after
ischemia and reperfusion injury in proximal tubular epithelial cells and interstitial cells of an
uncertain cell type that morphologically resembled infiltrating monocytes. We demonstrated that
cultured renal fibroblasts are capable of producing RA when co-cultured with F9-RARE-LacZ
reporter cells. Furthermore, we showed that there is a significant upregulation (3.2 +/- 1.2 fold
increase, p=0.002) of the M2 marker Arginase-1 in cultured macrophage-like Raw264.7 cells
incubated with conditioned media from renal proximal tubular cells (RPTC) treated with all trans
retinoic acid (ATRA) compared to Raw264.7 cells treated with RPTC media and ATRA alone.
Based on these findings we propose a new model in which infiltrating peritubular cells secrete
RA early after injury which promotes secretion of an as yet unidentified factor by proximal
tubular epithelial cells which induces macrophage switching to a pro-regenerative phenotype.
Early activation of RA during AKI may therefore limit M1 macrophage differentiation and tissue
damage.
Abstract
65
Basal insulin treatment with detemir improves glycemic control but does not potentiate
weight loss in obese individuals with type 2 diabetes mellitus on a hypocaloric diet
Matthew A. Buendia (University of Tennessee Health Science Center – College of Medicine),
BettyAnn Chodkowski, Hakmook Kang, Malcolm J. Avison, Heidi J. Silver, and Kevin D.
Niswender, Vanderbilt University School of Medicine
Lowering blood glucose level is a primary treatment strategy used to avoid long-term
complications of type 2 diabetes mellitus (T2DM). As T2DM progresses, patients typically
require insulin to maintain glycemic control; however, insulin therapy is often associated with
weight gain, which is contrary to clinical goals in diabetes care. The goal of this study is to
quantify improvements in glycemic control associated with low dose basal insulin detemir
therapy and weight loss in obese insulin-naïve individuals with T2DM. This is a 26-week,
interventional, randomized, controlled trial. Subjects were randomized to receive insulin detemir
(IDet) treatment or no treatment (No IDet). During the first 4-week period, participants were
asked to maintain a constant body weight. After the 4 weeks, both groups began the weight loss
phase, which consisted of 20 weeks of low-calorie diet intervention (Diet) in addition to
continuation of insulin if in the insulin group. Mean change in body weight from baseline did not
differ between No IDet (-5.20 ± 0.88 kg) and IDet (-5.52 ± 0.85 kg) groups (p=0.4559) over the
24-weeks. Glycemic control assessed by fasting plasma glucose (FPG), hemoglobin A1c
(HbA1c), and mixed meal tolerance testing (MMTT) improved in both groups, but occurred
earlier in the IDet treatment group, as seen by significant differences between groups at Week
14. Interestingly, 4 weeks of IDet alone in the absence of weight loss significantly lowered FPG
(-21.71 ± 7.43 mg/dL) compared to no IDet (1.08 ± 3.65 mg/dL; p=0.0018). Glycemic control
(FPG, HbA1c, and MMTT) was significantly improved in the subjects receiving both 14 weeks of
IDet + 10 week Diet compared to the No IDet + 10 week Diet group even though the groups did
not differ in weight change from baseline. By the end of the study, both groups had significant
improvements in glycemic control and weight loss from baseline. IDet treatment for 4 weeks,
independent of weight loss, improved specifically FPG, and potentially accelerated FPG, HbA1c
and MMTT improvements by Week 14 compared to Diet alone. At the end of the study, week
24, IDet+Diet was not superior to Diet alone in terms of mean changes in glycemic control and
body weight. Our results suggest that low dose basal insulin detemir accelerates improvements
in glycemic control compared to weight loss alone, thereby reducing the risk of long-term T2DM
complications. These observations have implications when developing appropriate and timesensitive drug regimen and treatment plans for patients with T2DM and obesity.
Abstract
66
The role of CSF-1 in macrophage proliferation and differentiation in acute kidney injury
Emily F. Kelly,1 Bing Yao,2 Yinqui Wang,2 Ming-Zhi Zhang,2 Raymond C. Harris,2
1.
Florida Atlantic University, Charles E. Schmidt College of Medicine, Boca Raton, FL, USA.
2.
Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, TN, USA.
Acute kidney injury (AKI) leads to injury of kidney epithelial cells, especially proximal tubule cells,
and to the activation of monocytes and macrophages. Following AKI, M2 or wound healing
macrophages are alternatively activated and signaled to proliferate by CSF-1 produced by the
renal proximal tubule cells. Upon M2 activation paracrine growth factors are produced that
target epithelial cells and fibroblasts allowing for cellular growth and cytoskeletal repair and
regeneration. We hypothesize that CSF-1 is critical for the recovery form AKI by acting as a
proliferation signal for M2, wound healing, and macrophage differentiation. Deletion of CSF-1 in
the renal proximal tubule cells will delay recovery from AKI by decreasing M2 macrophage
proliferation and, as a result, decrease tissue repair and regeneration. Diphtheria toxin receptor
(DTR) mice, with human HB-EGF cDNA construct, selectively express the DTR receptor within
the renal proximal tubular cells. DTR mice were crossed with CSF-1 floxed mice to generate
CSF-1flox/flox DTR (wild type) mice. Additionally, knockout mice were created by crossing the DTR
mice with γ-GT Cre mice generating γ-GT Cre; CSF-1flox/flox DTR (knockout) mice in which CSF1 in the renal proximal tubule epithelial cells was deleted. When injected with the diphtheria
toxin these DTR mice (CSF-1flox/flox DTR mice and γ-GT Cre; CSF-1flox/flox DTR) developed AKI.
Through blood urea nitrogen (BUN) levels, flow cytometry, and qRT-PCR, recovery from AKI
and the degree of macrophage proliferation can be measured. CSF-1 knockout mice showed
increased BUN levels which correlated to the delayed rate of recovery from AKI. Through flow
cytometry it was shown that blocking CSF-1 caused diminished M2 (F4/80+, CD206+, CD11b+)
cellular proliferation in CSF-1 KO mice (P < 0.01; n=4). qRT-PCR revealed that CSF-1 depleted
mice (KO) displayed marked reduction in mRNA levels of M2 dependent growth factors (P <
0.1; n=4). Depletion of M2 macrophages resulted in delayed renal tissue repair and increased
kidney fibrosis. Overall, CSF-1 plays an essential role in M2 polarization. When the CSF-1
signal is absent, M2 macrophage proliferation declines resulting in a decreased production of
M2 growth factors and consequently delayed recovery from AKI. CSF-1, therefore, is critical for
the activation of M2 macrophages and their role in repair and differentiation after AKI.
Abstract
67
Can website information be used to identify guideline-concordant weight loss programs
in the community?
Benjamin Bloom (University of Maryland School of Medicine), Dr. Ambereen Mehta, Dr.
Kimberly Gudzune, Johns Hopkins University, Welch Center for Epidemiology, Prevention and
Clinical Research
Background: Weight loss has been demonstrated to prevent diabetes mellitus. Guidelines
recommend that primary care providers (PCP) refer patients with obesity to high intensity weight
loss interventions; however, many PCPs may be unaware of locally available programs.
Objective: Our objective was to determine the reliability of web-based information regarding
guideline-concordant practices of community weight loss programs in Maryland.
Methods: We conducted a systematic online search for community-based weight loss programs,
and performed a content analysis to abstract weight management practices from their websites.
We then randomly selected 50 of these programs for a telephone survey to obtain actual
program components and practices. We compared the accuracy of web and telephone data
among this vanguard group to determine reliability of web-based information using crosstabulations.
Results: We identified 191 programs and recruited 41 for the telephone survey. Among this
vanguard, 41% were physician delivered and 98% were in-person interventions. From the
website, we could abstract program intensity (frequency of contacts) reliably among 37% of
programs. Most misclassified programs were graded as a lower intensity as compared to phone
report. Content analysis correctly identified programs containing dietary components (71%),
exercise components (53%), and any behavioral component (51%). Both exercise and
behavioral components were often not reported on the websites, despite use of these guidelinebased practices as reported by phone. We accurately identified 90% of programs that used
FDA-approved anti-obesity medications; however, 29% of programs that dispensed
nutraceuticals were misclassified. Typically, websites failed to mention the use of these nonguideline-supported supplements (43%), despite endorsement by program staff of their use.
Significance: Evaluation of weight loss programs’ web-based content can reliably reflect some
measures of guideline-concordant care and underestimates other aspects. This information
could potentially be used to create a decision aid to facilitate PCPs’ assessment of local weight
loss programs, thus enhancing referrals to guideline-concordant programs.
Abstract
68
Development of CD8+ Tregs for in vivo Islet Protection.
Courtney N. Altshuler (Keck School of Medicine – USC), Blair T. Stocks, Andrew F. Marshall,
and Daniel J. Moore, Vanderbilt University Medical Center, Nashville, TN
Islet transplantation for the cure of Type 1 diabetes is challenged by two fundamental
immunologic barriers: recurrent autoimmunity against islet beta cells and alloimmunity against
MHC mismatches and novel antigens within the graft. Both of these deleterious processes are
driven by ongoing interactions between T and B lymphocytes. It is now known that suppression
of direct, ongoing T cell–B cell interactions can be executed by CD8+ Tregs, which are highly
potent regulators of autoimmunity. We investigated the hypothesis that CD8+ Tregs are required
for the induction of transplantation tolerance to islets in T1D and that their insufficiency
predisposes to autoimmunity and graft rejection. We tested this by developing an assay to
measure alloantibody production in mice challenged with MHC-mismatched splenocytes,
measured the responses of different cell types (CD8+, CD4+ TFH, and germinal center B cells) at
7-day intervals, and tested to see whether fully activated CD8+ Tregs could suppress this
alloantibody response. Our results show that B6 mice immunized with MHC-mismatched C3H
splenocytes develop a measurable alloantibody response (anti-C3H IgG1) by day 7, and peaks
by day 14, remaining stable at day 21. Based on subset analysis, we detected an increase in
naïve CD8+ T cells, a decrease in memory CD8+ T cells, and no significant change in CD8+ Treg
levels at 14 and 21 days vs. 7 days. In vivo, activated CD8+ Tregs were able to delay the
development of diabetes in a stringent, adoptive transfer model; we are extending these findings
to islet transplantation. Overall, we propose that development and activation of CD8+ Tregs will
be a critical new target to promote the success of islet transplantation in patients with T1D.
Abstract
69
Identification of the cellular source of hepatic Notch signaling in obesity and nonalcoholic steatohepatitis.
Ignacio J. Contreras (College of Physicians and Surgeons, Columbia University), Changyu Zhu,
Utpal Pajvani, Columbia University
Notch signaling is an essential pathway that determines cell fate during development. Recently,
Notch has been shown to be highly activated in patients with non-alcoholic steatohepatitis
(NASH). NASH is a condition where the liver undergoes lipid accumulation, inflammation and
fibrosis. It can ultimately lead to cirrhosis or hepatocellular carcinoma.1 Its pathogenesis is not
yet well understood. We hypothesized that hepatic Notch signaling to be a contributing factor to
the pathogenesis of NASH. We tested this visually by using immunostaining in Nicastrinknockout mice and wild-type mice that were fed on methionine-and-choline-deficient diet
(MCDD), which is a useful animal model of NASH. Nicastrin is a protein that makes up a part of
the gamma-secretase, an enzyme that cleaves the Notch receptor within the plasma membrane.
We generated liver-specific Nicastrin knockout mice by crossing Nicastrin-floxed mice with
Albumin-Cre mice (Nicastrinfl/fl;Albumin-Cre genotype). We confirmed the efficacy of deletion of
Nicastrin by using quantitative PCR (qPCR) and immunofluorescence. Compared with controls,
liver-specific Nicastrin knockout mice showed a great reduction of Nicastrin mRNA and protein
in the livers. We co-stained liver sections with Notch target protein Hey1 and cell-type specific
markers that would allow us to visually identify the cell type(s) that display Notch activity within
the liver, be it a hepatocyte, Kupffer cell, endothelial cell, or stellate cell. We found that Hey1 is
expressed in hepatocytes in control mouse livers, but its level is decreased in hepatocytes in
Nicastrin knockout livers. Interestingly, we noticed that other cell types, such as endothelial cells,
might be a source of Hey1 activity. We did not have enough time to adequately test out all
possibilities, given the fact that not all antibodies work for immunofluorescence, although we
remain optimistic to find more conclusive data that point to the fact that Notch signaling is
behind NASH.
1
Ertle, J. et al. Non-alcoholic fatty liver disease progresses to hepatocellular carcinoma in the
absence of apparent cirrhosis. Int J Cancer 128, 2436-2443, doi:Doi 10.1002/Ijc.25797 (2011).
Abstract
70
Relationship between skeletal muscle mitochondrial stereomorphometry and insulin
resistance
1
Jay Mottla (Georgetown University School of Medicine), 2Caroline Suresh, 2,3,4Steven K.
Grinspoon, MD, 2,3,4Hideo Makimura, MD, PhD
1
Georgetown University School of Medicine, Washington, D.C., 20007, 2Program in Nutrition
Metabolism, Massachusetts General Hospital, 3Neuroendocrine Unit, Massachusetts General
Hospital, 4Harvard Medical School, Boston, MA 02114
Currently 32% of Americans are obese with a body mass index (BMI) ≥30kg/m2. Insulin
resistance may contribute to metabolic diseases associated with obesity. Recent studies have
implicated mitochondrial dysfunction in mediating insulin resistance. We hypothesize insulin
resistance is associated with a decrease in skeletal muscle mitochondrial number, therefore
leading to decreased mitochondrial function. Thus, we investigated the relationship between
characteristics of mitochondrial stereomorphometry and measures of insulin resistance. As an
exploratory endpoint, we assessed the relationship between mitochondrial stereomorphometry
and body composition. We recruited 20 abdominally obese men and women from the Boston
metropolitan area. Skeletal muscle tissue was obtained via percutaneous muscle biopsy. A
novel, semi-automated software program analyzed electron microscope images of the muscle
tissue. The program generated stereomorphometry parameters including total number of pixels
occupied by mitochondria, total density of mitochondria, number of mitochondria and average
density of individual mitochondria. Insulin sensitivity of each subject was determined via the
“gold-standard” hyperinsulinemic-euglycemic clamp as well as fasting insulin, glucose, HOMA
and HbA1c. Subjects were 70% male, 44.9±1.58 years old, with BMI of 39.5±1.07 kg/m2,
median HOMA index of 4.38 [3.31, 5.21], median glucose infusion rate (GIR) of 3.16 [2.26, 3.62]
on hyperinsulinemic-euglycemic clamp, and median mitochondrial number of 56.9 [53.7, 61.5].
GIR was positively associated with increased total mitochondrial pixels (ρ=0.54, P=0.02),
density (ρ=0.52, P=0.02), and number (ρ=0.52, P=0.02). However, neither fasting glucose,
insulin, HOMA nor HbA1c were associated with descriptive parameters of mitochondria (all
P>0.05). In addition, total body fat percentage was negatively correlated with mitochondrial
pixels (ρ=-0.59, P=0.006), density (ρ=-0.57, P=0.009) and average density (ρ=-0.46, P=0.04).
Total lean mass percentage was positively correlated with mitochondrial pixels (ρ=0.60,
P=0.005), density (ρ=0.58, P=0.007) and average density (ρ=0.52, P=0.02). In conclusion, we
demonstrated a significant positive association between the parameters of mitochondrial
stereomorphometry and insulin resistance using hyperinsulinemic-euglycemic clamp but not
with more crude measures of insulin sensitivity. The observed relationship is consistent with
previous publications, but the determination of mitochondrial parameters via semi-automated
software demonstrates objective and reproducible evidence for the association. Additionally, a
previously unpublished relationship between mitochondrial parameters and body composition is
reported.
Abstract
71
Cell Culture Optimization for in vitro Chondrocyte Differentiation
Elizabeth J. Olecki (Northeast Ohio Medical University), Matthew R. Karolak, and Florent
Elefteriou, Vanderbilt Center for Bone Biology, Vanderbilt University
Many diseases affecting growth and bone repair are the result of genetic mutations in
chondrocytes. One way to study the etiology of these diseases is in vitro culture of
differentiating chondrocytes. Unfortunately, because chondrocyte proliferation and
differentiation is highly dependent on precise spacio-temporal interactions between various cell
types, cytokines and matrix proteins, it is very difficult to differentiate chondrocytes in culture.
Because chondrocytes are embedded in an ion and growth factor rich matrix, we hypothesized
that chondrocytes will more reliably differentiate if the hypoxic and osmotic conditions of the
growth plate are mimicked in vitro. To test this hypothesis, we harvested chondrocytes from P5
murine ribs and plated them in micropellets to mimic hypoxic conditions while also growing the
cells in a standard media or standard media supplemented with 100 mOsm NaCl or 200 mOsm
NaCl. Chondrocyte pellets were harvested at 0, 2, 5, 10, and 15 days following plating and
were then stained for matrix production with Alcian blue and assessed for differentiation by
quantitative PCR. We found that matrix production was increased in day 2-15 differentiated WT
chondrocytes grown in +100 mOsm and +200 mOsm when compared to the standard
media. Using Col2, Acan, and Col10 as gene expression markers of chondrocyte commitment
and hypertrophic differentiation, we found that a +200 mOsm supplementation resulted in the
most reliable differentiation and maintenance of chondrocyte commitment. We also used Nf1-/chondrocytes (taken from Nf1Col2-/- mice) to confirm that chondrocyte differentiation, as assessed
by Col10 gene expression, to hypertrophy is impaired when Nf1 is deleted. As expected,
expression of Col2 and Acan were not affected by Nf1 loss-of-function. Finally, we found that
chondrocytes plated in micropellets immediately following harvest from P5 pups versus
chondrocytes expanded for one week in culture prior to pelleting showed the best maintenance
of chondrocyte commitment and differentiation to hypertrophy (Col2 and Col10 gene
expression, respectively). In conclusion, mouse rib chondrocytes showed the best overall
differentiation when grown in vitro with +200 mOsm NaCl conditions and not expanded in
culture.
Abstract
72
Medication Adherence: An Important Factor in Understanding Racial Disparities in
Glycemic Control
Bradley W. Harrison, BS (Mercer University School of Medicine); Lindsay S. Mayberry, MS,
PhD; Chandra Y. Osborn, PhD, MPH; Vanderbilt University Medical Center
Among adults with Type 2 diabetes mellitus (T2DM), non-White race has been consistently
associated with less medication adherence and worse glycemic control. Less medication
adherence has also been associated with worse glycemic control. Few studies have explored
less medication adherence as a mechanism by which non-Whites have worse glycemic control.
In an effort to build upon this literature, we tested the hypothesis. We collected data from 314
adults with T2DM who were prescribed oral anti-hyperglycemic medication(s) and/or insulin and
presented for an appointment at a Federally Qualified Health Center in Nashville, TN. Racial
(White vs. non-White) differences on sociodemographic and clinical characteristics were
examined with Fisher’s exact and Mann Whitney U tests. We used indirect effect tests with biascorrected bootstrapping (5000 samples) to test for mediation. We conducted an unadjusted
model and a model adjusted for apriori covariates (i.e., age, gender, education, income, insulin
status, duration of diabetes). The average participant was 51.8 ± 11.7 years old. Nearly twothirds were female (65%), whereas non-Whites constituted 63%; the average years of education
was 11.9 ± 2.9; 71.2% reported annual income below $15,000. In unadjusted analysis, nonWhite race was associated with less medication adherence (coefficient = -1.36, p<0.05) and
worse glycemic control (coefficient = 0.92, p<0.001), less medication adherence was associated
with worse glycemic control (coefficient = -0.09, p<0.001), and less medication adherence
mediated the association between non-White race and worse glycemic control (unadjusted
indirect effect = 0.128 [0.021,0.296]; adjusted indirect effect = 0.076 [0.001,0.223]). The
adjusted model explained 19.9% of the variance in glycemic control (F = 8.079, p<0.001). Our
results suggest medication nonadherence is one mechanism underlying racial disparities in
glycemic control. Study limitations include sampling from a single clinic, under-representation of
White male participants, and the use of self-reported measures. Interventions targeting
medication nonadherence may also help reduce disparities in glycemic control among lowincome patients with T2DM.
Abstract
73
Type 2 Diabetes may affect the potential effects of age and BMI on markers of skeletal
muscle mitochondrial structure and function.
Kerrie Nguyen (Tulane University School of Medicine), Theodore Ciaraldi, PhD, and Robert R.
Henry, MD. VA San Diego Healthcare System and University of California, San Diego
The skeletal muscle (SkM) of type 2 diabetes mellitus (DM2) patients is known to be structurally
and functionally compromised, which is believed to contribute to insulin resistance and
enhanced fatigability. The presence of DM2 may involve perturbations in SkM mitochondrial
size, number, and efficiency, resulting in the SkM’s inability to properly oxidize glucose and fatty
acids. We hypothesized that age and weight may affect mitochondrial structure and function,
and that these effects are different in the presence of DM2. To test this we evaluated the
expression of proteins involved in mitochondrial biogenesis (mitochondrial transcription factor A,
Tfam), structure (porin and optic atrophy 1, OPA1) and activity (citrate synthase, CS) in SkM
tissue obtained from non-diabetic (ND) and DM2 human subjects of varying ages (18-64 yrs)
and BMIs (20.6-43.0 kg/m2). The two groups did not differ with regard to average age or BMI.
In ND there was a tendency (p=0.054) for a negative association between age and Tfam protein
content; all other markers were independent of age. However, in DM2 subjects, CS (p=0.0519)
and OPA1 (p=0.0433) protein content were positively correlated with age, while there was no
such association with Tfam. The only significant relationship between BMI and the
mitochondrial markers examined was a positive one seen in ND subjects for the CS/porin ratio
(p=0.0246), a surrogate for mitochondrial efficiency, but not in DM2 subjects (p=0.019 between
groups). There were no significant differences between the ND and DM2 groups in the
mitochondrial structure and function markers examined. In summary, there were modest effects
of age and BMI on indicators of SkM mitochondrial structure and function. However, the nature
of these effects differed in some instances between ND and DM2 subjects, providing partial
support for our hypothesis of responses unique to DM2 subjects to age and BMI.
Abstract
74
The role of ER and oxidative stress in overnutrition-induced β-cell neogenesis
Tanav Popli (Indiana University School of Medicine, Indianapolis, IN), Wenbiao Chen, Lisette
Maddison, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville,
TN
Pancreatic β-cells exhibit two mechanisms to compensate for chronically increased blood
glucose levels: increased insulin biosynthesis and secretion and increases in total β-cell mass.
Individuals with robust β-cell compensatory mechanisms are thought to be protected from
developing Type 2 Diabetes, as opposed to individuals whose pancreatic islets have a limited
capacity for mass increase. Previous work demonstrates that the increase in β-cell mass is due
to the induction of β-cell, however, the specific intracellular events involved in this process are
not yet well-characterized. Further work by Dr. Chen’s group points to a role for ER and
oxidative stress in β-cell induction. To test the hypothesis that activation of ER and oxidative
stress response pathways in pancreatic β-cells of zebrafish larvae plays a role in compensatory
β-cell neogenesis, we created 3 different knockout lines of zebrafish, atf3-/-, hsf1-/-, and sirt1-/- to
disrupt the ER and oxidative stress response in β-cells exposed to excess nutrition. Differences
in β-cell compensatory capacity were assessed by manual quantification of islet β-cell number
in 5% yolk fed and unfed control larvae 6 days post fertilization. No significant difference was
found between any of the four atf3 larval groups (overfed atf3-/-, 36.1±8.7 cells, n=14, overfed
atf3+/- or atf3+/+,36.6±9.2 cells, n =54, unfed atf3-/-, 35.5±6.7, n=18, unfed atf3+/- or atf3+/+,
38.2±8.0, n=47). Overfed hsf1-/- (40.6±5.4 cells, n=17) had significantly more β-cells than unfed
hsf1-/- larvae (33.5±6.2 cells, n=7), though β-cell number in overfed hsf1 nonmutants (38.8±7.3
cells, n=27) was not significantly different than unfed hsf1 nonmutants (36.4±6.5 cells, n=61),
and no difference was found between mutants and nonmutants in either treatment group.
Similarly, the four sirt1 larval treatment groups exhibited no significant differences in β-cell
number between genotypes or overfed and underfed sirt1 nonmutants (overfed sirt1+/- or
sirt1+/+,41.8± cells, n =30, unfed sirt1+/- or sirt1+/+, 41.0±, n=17), but overfed sirt1-/- larvae
(45.4±6.9 cells, n=11) had significantly more β-cells than unfed sirt1-/- larvae (39.9±8.0, n=20).
This experiment suggests that knockouts of atf3, hsf1, and sirt1 do not affect β-cell neogenesis.
However, the lack of previously documented effects between the control larvae implies more
data is needed to definitively draw this conclusion. The possibility of a heterozygous effect on βcell neogenesis that may be confounding the data cannot be discounted, and is being explored.
Abstract
75
Ascorbate recycling in human brain vascular pericytes
Tarun Jain (Indiana University School of Medicine, Indianapolis, IN), William H. Parker, M.
Elizabeth Meredith, Zhi-chao Qu, James M. May, Department of Medicine, Division of Diabetes,
Endocrinology, and Metabolism, Vanderbilt University, Nashville, TN
One of the major complications of diabetes mellitus is diabetic retinopathy; according to the
Centers for Disease Control and Prevention (CDC), 30% of people with diabetes over the age of
40 are affected, with blindness occurring in 5% of those with diabetes. The condition is
characterized by loss of vision due to microvascular damage in the retina, which results from
oxidative stress caused by high blood glucose concentrations. A chronic increased superoxide
concentration will lead to depletion of cellular antioxidants, including Vitamin C (ascorbate),
which in turn leads to protein, nucleic acid, and lipid damage. The resulting apoptosis of
pericytes is one of the earliest steps in microvascular damage, leading to loss of structural
support and increased permeability of the endothelial barrier. Our studies have demonstrated
that ascorbate supplementation reduces the permeability of the endothelial barrier, as well as
prevents apoptosis in endothelial cells and pericytes. Ascorbate acts as a one-electron donor,
and the cell must regenerate ascorbate in order to maintain part of its antioxidant activity. While
this reduction or recycling of oxidized ascorbate has been studied in human umbilical vein
endothelial cells (EA.hy926), the purpose of this study is to characterize the process in human
brain vascular pericytes (HBVP). This would serve both as a measure of ascorbate recycling
and total cellular antioxidant reserve. When pericytes were loaded with ascorbate, increasing
concentrations of ascorbate were hypothesized to lead to increased antioxidant activity of
pericytes. Futhermore, because pericytes should be able to recycle ascorbate, antioxidant
activity of pericytes was hypothesized to continue over time, and total antioxidant activity was
hypothesized to increase with relation to time. Recycling and antioxidant activity of ascorbate
was measured by ascorbate-dependent ferricyanide reduction; cells cultured in 6-well plates
were treated with varying concentrations of ascorbate, after which they were treated with 500
µM potassium ferricyanide. This assay is an indirect measure of ascorbate activity through the
transfer of an electron from ascorbate to ferricyanide via a transmembrane protein. In both
EA.hy926 and HBVP, an increase in the concentration of the initial ascorbate treatment lead to
an increase in the concentration of ferrocyanide, the reduced form of ferricyanide. However,
endogenous ascorbate was present in HBVP, and thus these cells were able to reduce a higher
concentration of ferricyanide to ferrocyanide both initially and overall over time, regardless of
initial ascorbate treatment. In order to account for this difference, both EA.hy926 and HBVP
were loaded with 250 µM ascorbate, which both the literature and our studies have shown
should saturate the cells. Interestingly, while the initial increase in ferrocyanide concentration
was higher in HBVP cultures, the rate of increase slowed down over time relative to EA.hy926
cultures. Nevertheless, the increase in the concentration of ferrocyanide in both cell groups
over time indicated that ascorbate activity had been maintained. These results suggest that
pericytes act similarly to endothelial cells in regulation of intracellular ascorbate concentrations,
although the rates of reduction or recycling may vary. Future experiments would focus on other
aspects of ascorbate recycling, such as reduction of dehydroascorbate (DHA), as well as the
behavior of other antioxidants within pericytes. Results from these studies can be used to
elucidate the mechanisms behind ascorbate’s ameliorative effects on the maintenance of the
blood-retinal barrier under oxidative stress, both in vitro and in vivo.
Abstract
76
Replication of association of a loss-of-function mutation in HSL with metabolic traits in
the Amish
Donique Parris (University of Maryland School of Medicine), Coleen Damcott PhD, Alan
Shuldiner MD, University of Maryland School of Medicine
Lipolysis is a metabolic pathway that regulates energy homeostasis through degradation of
intracellular triacyglycerol (TAG) and release of fatty acids for use as energy substrates or lipid
mediators in cellular processes. Both excess (e.g. obesity) and insufficient (e.g. lipodystrophy)
white adipose tissue (WAT) stores, the primary energy depot, are associated with insulin
resistance and increased risk for type 2 diabetes. Thus, maintenance of normal WAT function is
critical in preserving whole body insulin sensitivity and energy homeostasis. Hormone-sensitive
lipase (HSL) is a key lipolytic enzyme with high affinity for diacylglycerol, but which also
hydrolyzes TAG, cholesterol esters, and retinol esters. Recently, a 19-base pair deletion in the
LIPE gene, which encodes HSL, was identified in the Amish. The mutation was associated with
absence of the HSL protein, dyslipidemia, hepatic steatosis, systemic insulin resistance, and
type 2 diabetes. The objective of this study was to identify additional carriers of the HSL
mutation in a second Amish cohort and determine its effects on metabolic traits, such as fasting
total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density
lipoprotein (LDL) cholesterol. We genotyped 1,076 DNA samples from Amish participants in the
Wellness Study and identified 33 heterozygote carriers (ID) and 1 homozygote carrier (DD).
Association analyses were then performed to determine which metabolic traits were significantly
associated with the HSL mutation while taking relatedness of the participants into account. Of
the metabolic traits analyzed, triglycerides and HDLs were the only two that had a statistically
significant association with the HSL mutation. The presence of the D allele was associated with
higher serum triglycerides (p=0.009) and lower HDL cholesterol levels (p=0.03). These data
provide replicating evidence of the reported effects of the HSL mutation on metabolic traits and
further highlight the importance of HSL in maintaining systemic lipid homeostasis.
Abstract
77
A peptide barcoding strategy to study insulin secretion from mixed cell populations.
Pooja Prasad (University of Rochester), Thomas Hennings, Gregory Ku, University of California
San Francisco
While a fraction of the numerous genes expressed in beta cells have been shown to be involved
in insulin secretion, we hypothesize that many more unidentified genes regulate insulin
secretion. A better understanding of insulin secretion has valuable applications for conversion of
an embryonic stem cell to an insulin-secreting cell and for drug targeting. Pooled RNA
interference and Cas9/CRISPR screens would allow the identification of novel genes involved in
insulin secretion. Towards that aim, our study’s goal was to develop and test a peptide
barcoding strategy to measure the amount of insulin being secreted from a mixed population of
cells with unique genes knocked down. We hypothesized that adding engineered peptide
sequences detectable by mass spectroscopy to C-peptide would allow us to monitor insulin
secretion. To test this system, we produced lentivirus containing a unique 20 amino acid tag and
a FLAG epitope tag appended to C-peptide and infected mouse pancreatic beta cells. Infection
rates were measured using droplet PCR from genomic DNA. We then performed a western blot
on cell lysates using an anti-FLAG antibody to detect the tagged C-peptide. Our western blot
showed a FLAG reactive band whose size is consistent with proinsulin, suggesting that the
presence of these tags may inhibit insulin maturation. To test whether the band of unexpected
size is due to incomplete processing, we are constructing a plasmid containing only the tagged
C-peptide, rather than tagged C-peptide within the context of preproinsulin. Before sending cells
to mass spectroscopy for detection of peptide tags and utilizing this method for studying insulin
secretion, we must ensure that the peptide sequences serving as a barcode are not affecting
secretion of insulin.
Abstract
78
Using Human Embryonic Stem Cells to Derive Pancreatic Beta Cells In Vitro
Deepti Pujare (New York Medical College), Audrey V. Parent, Holger A. Russ, Matthias Hebrok,
University of California- San Francisco
A novel approach to treating diabetes is to transplant hESC-derived beta cells into patients.
Current methods of treating diabetes include pancreatic transplantation or infusion of pancreatic
islets into the bloodstream. However, these methods have various limitations such as the lack
of sufficient donors. Our hypothesis is that we can create functional pancreatic beta cells in
vitro from human embryonic stem cells (hESCs). The hESC line MEL1/INS-GFP was
differentiated in vitro using two different protocols (protocol 1 and 2). Immunofluorescence and
flow cytometry were used to characterize and compare the cells generated using both protocols
at various stages of differentiation. Both methods generated different proportions of pancreatic
progenitors as well as cells that express markers characteristic of beta cells (C-peptide, PDX1,
NKX6.1, NKX2.2) and other pancreatic cell types (Glucagon, Somatostatin). Importantly, cells
differentiated using protocol 2 had more cells with characteristics of mature beta cells
(expressed important transcription factors such as NKX6.1 and PDX1 and did not express other
hormones). The proliferation of pancreatic progenitors and beta-like cells was also assessed
using Ki67. Our study suggests that hESCs can be induced to differentiate into more mature
beta-like cells in vitro using an improved differentiation protocol.
Abstract
79
ApoE Receptor 2 (LRP8) Cleavage Product Dependent Transcriptional Programs of
Learning and Memory
Hyun Chun (Stony Brook Medicine), Patricia Montilla Pérez, Francesca Telese, Michael Geoff
Rosenfeld Department of Medicine, UCSD, La Jolla, CA
Neuroimaging studies on diabetes type 2 patients show increased cortical and hippocampal
atrophy correlated with cognitive dysfunction, independent of hypertension. Interestingly,
preliminary studies show that the ApoE/reelin receptor (LRP8) is a new substrate of gammasecretase activity that releases an intracellular domain (ICD) upon binding of ligands. LRP8
knockout mice show deficits in hippocampal-dependent associative learning which prompts the
investigation behind the molecular mechanisms of how LRP8-ICD affects cognitive abilities in
the brain. To test the hypothesis that the intracellular domain of LRP8 plays a direct role in the
regulation of transcriptional programs related to learning and memory formation, we combine
global genomic approaches, such as RNA-seq and ChIP-seq, to behavioral paradigms using
LRP8 KO mice as an in vivo model. Global genomic approaches are particularly useful in
investigating transcriptional programs in an unbiased way. By RNA-seq, LRP8 KO mice have
decreased expression of learning and memory related genes using gene ontology
categorization. To further understand how the differential expression and cognitive dysfunction
phenotype is mediated by LRP8 biochemically, subcellular protein isolation and Western blots
were used to localize the gamma secretase cleavage product of LRP8 to the nucleus.
Supporting our hypothesis, LRP8-ICD shows transcriptional activity when tested in a Gal4
luciferase assay. To investigate the genome-wide binding pattern of LRP8-ICD, a BLRP/BirA
expression system in transgenic mice was combined with strepdavidin-ChIP-seq for LRP8-ICD.
Though ChIP-seq results are pending, these data suggest that the gamma secretase cleaved
intracellular domain of ApoE receptor influences transcriptional programs of learning and
memory through an epigenomic regulation. These observations also have clinical implications
for better understanding cognition in the context of disease such as diabetes and dyslipidemia
while providing an opportunity for new therapeutics and biomarkers.
Abstract
80
Bariatric surgery may increase expression of IR-beta and Akt in subcutaneous
adipocytes.
Ryan Beardsley (University of Illinois College of Medicine), Matt Piron, Milad Abusag, Matthew
Brady, University of Chicago
Bariatric surgery has been shown to improve insulin sensitivity in obese, insulin resistant
patients as soon as 2 weeks after surgery, before any significant long term weight loss has
occurred. This shows us that a significant amount of the anti-diabetic effects of bariatric surgery
occurs in a mechanism independent of that induced solely by a decrease in adiposity, but the
intracellular changes and molecular mechanisms that produce this benefit are not yet clear. We
hypothesized that bariatric surgery increased expression of the insulin receptor beta subunit (IRbeta) and Akt (also known as PKB, or Protein Kinase B), two vital proteins in the insulin
signaling pathway, supposing that such a change could explain at least part of the significant
changes in insulin sensitivity that occur. Subcutaneous adipose tissue biopsies were taken
approximately two weeks before and two weeks after bariatric surgery in 8 patients (all of whom
had either a Roux-en-Y gastric bypass or duodenal switch procedure) and subjected to insulin
signaling assays (being stimulated for 10 min by increasing concentrations of insulin) before
being Western blotted for IR-beta, total Akt (tAkt), and S473 phosphorylated Akt (pAkt, a strong
indicator of activation of the insulin signaling pathway), with beta-actin being blotted as a loading
control. Densitometry was performed on the resultant images collected from the antibody
visualization, and ratios of pAkt:tAkt, pAkt:beta-actin, tAkt:beta-actin, and IR-beta:beta-actin
were calculated. The mean of each ratio was higher post-op than pre-op, but none were
statistically significantly higher when taken as a whole. The mean post-op tAkt:beta-actin (1.82
± 0.76) was higher than the pre-op tAkt:beta-actin (0.97 ± 0.13), and mean post-op IRbeta:beta-actin (2.08 ± 0.98) was higher than the pre-op IR-beta:beta-actin (1.17 ± 0.15), but
due to the high variability from one patient to the next the post-op increases were not significant
(p>0.05). The 0.5nM insulin stimulation post-op samples, though, had a significantly higher
pAkt:tAkt than the 0.5nM insulin stimulation pre-op samples (p=0.032). For all other insulin
stimulation concentrations the pAkt:tAkt and pAkt:beta-actin ratios were also at least greater
post-op than pre-op, although no others were significantly higher. The variation between these
patients prevents any solid conclusions from being drawn from this data, but it does suggest to
some degree that expression of IR-beta and Akt in subcutaneous adipocytes generally
increases after bariatric surgery. The apparent post-op trends towards increased expression of
IR-beta and Akt, along with more dramatic increases in pAkt:tAkt, could reasonably be expected
to be more pronounced in patients who are considered fully diabetic before bariatric surgery.
Abstract
81
An Overview of the Recruitment Strategies for GRADE (Glycemia Reduction Approaches
in Diabetes: A Comparative Effectiveness Study)
Verona Young (Stony Brook University School of Medicine); Patricia Kringas RN, MA, CDE;
Camille Hausheer BS; Diabetes And Endocrinology Research Center (DERC) Columbia
University Medical Center
Over the past century, type 2 diabetes has become an epidemic that is currently affecting up to
1 in 3 Americans. According to recent estimates, the incidence of type 2 diabetes increased to
1.9 million while the prevalence currently exceeds 24.5 million. When deciding which medication
is most optimal at lowering and maintaining good glycemic control, practitioners often encounter
a major challenge due to the surplus of glucose-lowering medication available on the market.
The Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE)
Study plans to address this issue by comparing the longevity outcomes of four commonly used
drugs through a randomized, open label clinical trial. Patients will be given the maximum
tolerated dose of metformin then randomized to receive one of the following medications: the
sulfonylurea glimepiride, the DPP-4 inhibitor sitagliptin, the GLP-1 agonist liraglutide, and the
basal insulin glargine.
Recruitment for clinical trials demands a multi-faceted approach. The Naomi Berrie Diabetes
Center (NBDC) has embarked on multiple approaches including pre-screening the diabetes and
nutrition classes, advocating that subjects become study ambassadors, fostering referrals from
primary care physicians, building connections with neighborhood clinics and hosting health fairs
and other community events. In-person recruitment, partnering with the American Diabetes
Association, and publicizing in the media (i.e. creating newspaper ads and a NBDC Facebook
newsletter) are amongst some of the other recruitment strategies implemented. This summer,
we have focused on increasing daily pre-screening calls by extracting participant contact
information from the center database as well as on-site recruitment by hosting a weekly
Diabetes Alert Day in the main hospital. These strategies resulted in an increase in the overall
recruitment numbers for the site, which we predict will continue to drive participant enrollment
during the months to come.
Abstract
82
Continuous glucose monitoring, hunger and food intake in non-obese, obese and
diabetic free-living individuals.
Janice S. Kim (Washington University School of Medicine), Janice J. Hwang M.D., Renata
Belfort-De Aguiar M.D. Ph.D., Robert Sherwin M.D., Yale School of Medicine
Background: Obesity and diabetes are serious problems in the U.S. that can be ameliorated
through diet and exercise. Previous research has found that both rapid declines as well as
absolute low levels of blood glucose are associated with increased hunger and food
consumption; however, no study thus far has looked into the glucose profiles of free-living nonobese (N-OB), obese (OB) and diabetic (DM) individuals in relation to hunger and food intake.
Hypothesis: We hypothesized that larger glucose declines, as opposed to absolute low levels of
glucose, will be associated with increased hunger, increased calorie consumption and
subsequent consumption of more calorie-dense foods.
Methods: Eight subjects ((6 F/ 2 M), age 31.4±5.5, BMI 27.6±5.8, 2 N-OB/ 4 OB/ 2 T1DM
patients) wore a continuous glucose monitor (Dexcom CGM) for five days while keeping a food
diary of hunger ratings (from a scale of 1-10, 1 being none and 10 being very hungry) prior to
meals and amounts of food consumed.
Results: Preliminary findings suggest that mean subjective hunger ratings were 5.9±2.1 and that
prior to each meal, mean glucose peaks were 132±46 mg/dL and mean glucose nadirs were
85±19 mg/dL. Hunger ratings were positively associated with glucose peaks (ρ=0.25, P=0.04)
but not associated with glucose nadirs (P=NS). Glucose declines correlated with subsequent
consumption of fat (ρ=0.34, P=0.005) and protein (ρ=0.32, P=0.009), but not carbohydrates
(P=NS).
Conclusion: In conclusion, increasing subjective hunger levels are more related to pre-prandial
glucose peaks as opposed to nadirs and furthermore, declines in glucose are associated with
the macronutrient content of subsequent meals. Our findings suggest that glycemic excursions
following a meal may play a role in hunger and food choices for the subsequent meal.
Abstract
83
Effect of reduced cardiac triglyceride turnover on insulin signaling and glucose
homeostasis.
Ngoc Bao Nguyen (University of Washington), Nathan Roe, PhD, Rong Tian, MD, PhD,
Mitochondria and Metabolism Center, University of Washington
Increased myocardial triglyceride (TG) accumulation is observed in patients with diabetes and
obesity. However, recent evidence implicates TG turnover rate, rather than total TG levels, as a
critical factor in cardiac metabolism and function. Preliminary findings in our lab demonstrate
that a reduction in TG turnover increases fatty acid oxidation while decreasing glucose oxidation,
although the mechanism governing this switch remains unclear. Altered fatty acid and TG
metabolism has been implicated in insulin resistance; we therefore hypothesized that reducing
TG turnover in the heart would reduce insulin sensitivity and lead to reduced glucose oxidation.
To test our hypothesis, inducible cardiac specific diacylglycerol:acyltransferase 1 (DGAT1)
deficient mice (iKO), a model of reduced TG turnover, were fasted for 16 hours and exposed to
either acute insulin stimulation (10 mIU/g body weight, i.p., tissues harvested 20 minutes postinjection) or chronic high fat diet feeding (5 weeks on diet containing 60% kcal fat). The insulin
signaling cascade in the heart was then evaluated via western blot. Compared to baseline
measurements, insulin-stimulation lowered blood glucose to similar levels in both control and
iKO animals. No difference in insulin-stimulated Akt or GSK-3β phosphorylation was observed
in iKO compared to controls. Additionally, Akt and GSK-3β phosphorylation was unchanged in
response to high fat feeding in both control and iKO animals, suggesting a minimal effect of
DGAT1 on insulin signaling. Lactate levels in the heart were significantly increased with insulin
stimulation in control animals, however this increase was not observed in iKO, suggesting a
decrease in insulin stimulation of glycolysis (n = 3-6/group, p < 0.05). Similarly, glycogen
content in control animals increased 2.6-fold with insulin over saline treatment, but no increase
was seen in iKO (n = 3-6/group, p < 0.01). Collectively, our data suggests that reduced TG
turnover does not significantly alter insulin signaling, but may affect insulin-stimulated glucose
uptake and/or metabolism, providing a different mechanism through which TG turnover
regulates glucose homeostasis.
Abstract
84
The role of α2A adrenergic receptors via Gβγ-SNARE inhibition in exocytotic glucosestimulated insulin secretion.
Charles Jose (University of Nevada School of Medicine), Zack Zurawski, Heidi Hamm,
Vanderbilt University
Gi/o-coupled GPCRs function through Gβγ subunits to inhibit exocytosis. This mechanism
works via: 1) inhibition of calcium entry by binding to the voltage-dependent calcium channel
and 2) Gβγ binding directly to the SNARE complex. α2A adrenergic receptors (α2AAR) utilize
Gβγ-SNARE inhibition to reduce glucose-stimulated insulin secretion (GSIS) in pancreatic beta
cells. Inhibited glucose-stimulated insulin secretion is an early sign of type 2 diabetes (T2D), a
condition affecting millions throughout the world. We hypothesize that α2A adrenergic receptor
signaling is overactive in T2D, and that this over activity is mediated via the interaction of Gβγ
with SNAREs. To test our hypothesis that over-active inhibition of insulin secretion by the
sympathetic system exacerbates T2D through decreased GSIS, we performed static culture
assays using isolated pancreatic islet cells from lean and diet-induced obese (DIO) mice. Islets
were incubated in 5.6mM and 16.7mM glucose static cultures with combinations of epinephrine
(1uM); VU0451223, a Gβγ-SNARE inhibitor (50uM); and tolbutamide (1uM). GSIS was
measured via the AlphaLISA insulin assay. In lean mice, islets exhibited reduced GSIS when
incubated with epinephrine. Islets incubated in VU0451223 enhanced tonic GSIS but did not
reverse the antagonistic effects of epinephrine on insulin secretion. Tolbutamide and
VU0451223 did not enhance GSIS in an additive manner. In DIO mice, islets exhibit nondifferential GSIS under varying glucose concentrations. The DIO mice used in this experiment
may have already experienced signs of beta cell failure, a condition that occurs in late-stage
T2D. The impaired function of VU0451223 in inhibiting Gβγ-SNARE interactions may be
attributed to either reduced potency or structural defects that prevent the small molecule
inhibitor from fully penetrating the pancreatic islet cell. These data suggest that further
screening and optimization of Gβγ-SNARE inhibitors is necessary to achieve the desired effect
of maintaining tonic GSIS while simultaneously reversing the antagonistic effects of α2A
adrenergic receptors on exocytosis. Suppressing α2AAR -mediated Gβγ-SNARE inhibition can
enhance insulin secretion while maintaining the critical physiological role of insulin secretion by
glucose and other modulators. Understanding the pathophysiological relevance of Gβγ-SNARE
inhibition in exocytotic GSIS can identify novel therapeutic targets to improve T2D management.
Abstract
85
Ventral Tegmental Area µ-Opioid Receptors are Important in Feeding Behavior in Obese
Rats.
Joel Amezquita (Charles Drew University/UCLA), Candace M. Reno, and Robert Sherwin, Yale
University
Mu opioid receptors (µORs) are widely expressed in the brain and are involved in regulation of
feeding and food reward. A canonical two neuron model of reward posits that brain µ-opioid
receptor activation produces reward by disinhibiting midbrain ventral tegmental area (VTA)
dopamine neurons through inhibition of local GABAergic interneurons leading to increased
dopamine neurotransmission and feelings of reward. Diet-induced obese (DIO) rats have
increased expression of µORs in the VTA, as well as absent dopamine and GABA responses to
re-feeding. It is hypothesized that knockdown of µOR expression in the VTA will decrease food
intake, preference for highly palatable food, and weight gain by restoring the dopamine and
GABA responses. To test this hypothesis, DIO adult, male, Sprague-Dawley rats underwent
stereotaxic surgery to induce µOR knockdown in the VTA through use of an adeno-associated
siRNA virus (AAV). Control groups received a random scrambled RNA AAV. Rats were placed
into one of six groups: 1) normal chow diet with control virus (NC-ScrAAV; n=3), 2) normal chow
diet with µOR knockdown (NC-µORKD; n=4), 3) high fat diet with control virus (HFD-ScrAAV;
n=2), 4) high fat with µOR knockdown (HFD-µORKD; n=4), 5) a choice of both diets with control
virus (Choice-ScrAAV; n=4), and 6) choice of both diets with µOR knockdown (Choice-µORKD;
n=4). The normal chow diet was 70% carbohydrates, 10% fat and 3.85 kcal/g. The HFD was
35% carbohydrates, 45% fat and 4.73 kcal/g. Food intake and body weight were measured
twice weekly for approximately two weeks before and after surgery. Daily body weight change
decreased in all groups from basal to two weeks after virus injection: NC-ScrAAV (3.29 ± 0.3 vs
1.04 ± 0.9%), NC-µORKD (3.12 ± 0.2 vs 1.82 ± 0.2 %), HFD-ScrAAV (3.92 ± 0.2 vs 1.90 ±
0.1%), HFD-µORKD (4.61 ± 0.4 vs 2.17 ± 0.2%), Choice-ScrAAV (3.68 ± 0.6 vs 1.39 ± 0.3%),
and Choice-µORKD (3.53 ± 0.3 vs 1.13 ± 0.37%). There were no differences in body weight
change among the groups. Daily calorie intake two weeks after virus injection decreased
compared to basal in the NC-µORKD group (82 ± 5 vs 60 ± 9 kcal/day; p < 0.04) and trended to
be reduced in the HFD-µORKD (96 ± 5 vs 81 ± 7 kcal/day; p < 0.11) and Choice-µORKD groups
(95 ± 8 vs 79 ± 7 kcal/day; p < 0.12). There were no differences in food preference for normal
chow or HFD between the two choice groups. These results indicate that µOR knockdown in the
VTA has no effect on body weight during the short time given in the protocol and that overall
food intake is decreased in the presence of normal chow, HFD, or choice of both. Surprisingly,
µOR knockdown had no effect on preference for HFD. This data suggests that µORs play an
important role in satiety and reduction of food intake and may have implications for obesity
treatment and prevention.
Abstract
86
Assessing Correlates and Inter-rater Reliability of the Surprise Question in Non-dialysis
Dependent CKD.
Megan Mizera (University of Central Florida College of Medicine), T. Alp Ikizler, Khaled AbdelKader, Vanderbilt University
Older adults with severe chronic kidney disease (CKD) frequently receive care at the end-of-life
that conflicts with their values and preferences. Prognostic uncertainty is a critical barrier that
prevents providers from engaging patients in timely prognostic and advance care planning
discussions. The surprise question (SQ), “Would you be surprised if this patient died within 12
months?” has been advocated as a practical tool to identify patients at high risk for short term
mortality; however, it’s validity and reliability in non-dialysis dependent CKD has not been
explored. We hypothesized the SQ would associate with cardiovascular disease (CVD),
congestive heart failure, comorbidity burden, and low albumin levels and have a moderate to
high inter-rater reliability between attendings and fellows. We conducted a cross-sectional
analysis of a prospective cohort study at Vanderbilt’s outpatient nephrology clinic. We asked
enrolled nephrology providers the SQ immediately following an eligible patient visit. Responses
were recorded using a simple dichotomous ‘Yes’/’No’ and a 5-point Likert Scale with lower
scores indicating less surprise. Patient characteristics were abstracted from the electronic
health record. SQ responses associated with multiple clinical markers in univariable analysis
(n=76) including age (ß=-0.46, standard error [SE]=0.18, p=0.01), CHF with decreased LVEF
(ß=-1.94, SE=0.54, p=0.001), hospitalization in the prior year (ß=-0.81, SE=0.31, p=0.01),
Charlson Comorbidity Index (ß=-0.15, SE=0.06, p=0.01), hemoglobin (per 1g/dL increase)
(ß=0.43, SE=0.11, p<0.001), and albumin (per 1g/dL increase) (ß=0.97, SE=0.44, p=0.03). The
dichotomous SQ demonstrated moderate inter-rater reliability (kappa = 0.42, SE=0.17, p=0.008,
n=29). These results suggest that the SQ response associates with known predictors of
mortality in non-dialysis dependent CKD. In addition, the SQ appears to have moderate interrater reliability among nephrology providers at different stages in training/practice.
Abstract
87
Elementary Students' Knowledge, Preferences, and Skills related to Food, Nutrition, and
Cooking in Chicago
Brooke Scheidemantle (Sidney Kimmel Medical College at Thomas Jefferson University),
Alexandra De Sorbo-Quinn (Pilot Light), Michael Quinn PhD, Althera Steenes, Deborah Burnet
MD (University of Chicago)
Background: Limited data exists regarding cooking education programs to teach healthy
nutrition to schoolchildren. “Pilot Light” is an existing program which works with Chicago Public
School leaders to build food and nutrition education into regular classroom lessons like math,
science, and English language arts, with cooking demonstrations by Chicago’s leading
chefs. Lessons align with the Common Core State Standards and Chicago Public School
Wellness Standards for nutrition. We used focus groups to understand baseline knowledge,
preferences, and skills related to food, nutrition and living a healthy lifestyle for third through fifth
graders in Chicago. These insights will be used to develop and expand the Pilot Light curriculum
for implementation in additional schools.
Methods: We developed partnerships with two summer camps in order to assess
children’s knowledge, preferences and skills. We conducted focus groups with children
attending a YMCA summer program on Chicago’s North Side and a Chicago Park District
summer camp on Chicago’s South Side. Research staff conducted focus groups using a semistructured guide developed to elicit children’s knowledge of “healthy” foods, experience and
interest in cooking, and influences on their eating behaviors. Focus groups were audio taped,
professionally transcribed, and analyzed for themes.
Results: 22 third- through fifth-grade children enrolled and participated in the study. Four focus
groups (two at each site) were conducted with 4-7 participants per group. Participants
comprised 11 girls and 11 boys, including 10 African Americans, 6 Latinos, and 6 Caucasians.
Preliminary themes are as follows: children are knowledgeable and interested with food and
nutrition, many children are engaged in cooking at home, and parents/media/role models
influence the child’s food choices. Formal analysis is currently underway.
Conclusions: This study provides insight into the perspectives and experience regarding food
and nutrition among school-aged children in summer camps in Chicago. The beliefs,
preferences and practices of these children can become potential leverage points in curriculum
development and implementation for teaching nutrition and cooking skills to school children.
Abstract
88
Calcium-activated potassium channels modulate pancreatic a-cell Ca2+ influx and
glucagon secretion
Kenneth R. Verlage1, Prasanna K. Dadi2, and David Jacobson2
1. Texas Tech University Health Sciences Center School of Medicine
2. Department of Molecular Physiology and Biophysics, Vanderbilt University
Introduction: Ca2+ influx into pancreatic a-cells through voltage-dependent Ca2+ channels
(VDCCs) is required for glucagon secretion and regulatory mechanisms of this process become
defective during the pathogenesis of diabetes mellitus. Potassium channels are the primary
regulators of membrane potential, and thus, regulate the activity of VDCCs. However, the roles
of Ca2+ activated potassium channels (KCa2+) during a-cell Ca2+ entry and glucagon secretion
have not been determined. Understanding how KCa2+ channels regulate glucagon secretion has
the potential to illuminate therapeutic targets that could be utilized to reduce hyperglucagonemia
and hyperglycemia in diabetic patients.
Hypothesis: KCa2+ channels hyperpolarize the a-cell membrane potential which limits Ca2+ entry
and glucagon secretion.
Methods: Ca2+ imaging was performed on mouse and human pancreatic islets and single cells
in low (1mM) and high (11mM) glucose conditions with and without inhibitors of small
conductance (SK), intermediate conductance (IK) or large conductance (BK) KCa2+ channels
(apamin, TRAM34 and iberiotoxin respectively). Glucagon secretion was assayed under similar
conditions. Lastly, immunofluorescent imaging was used to detect IK expression in mouse and
human pancreatic sections.
Results: In mouse single a-cells, inhibition of SK and BK channels enhanced a-cell Ca2+ influx
under low glucose conditions, increasing Ca2+ levels by 36.18% (p < .01) and 42.03% (p < .001)
respectively. SK and BK channels also limited low glucose induced Ca2+ influx into a-cells
within clusters of islet-cells and when inhibited increased Ca2+ influx (by 23.72% (p < .05) with
SK channel inhibition and 27.31% (p < .05) with BK channel inhibition). IK channels are also
expressed in pancreatic islets and we find that mouse and human pancreatic sections show the
highest expression of IK channels in glucagon positive a-cells. Interestingly, inhibition of IK
channels caused significant increases in a-cell Ca2+ influx under both low and high glucose
conditions. IK channel inhibition caused a 41.76% (p < .001) increase for mouse single a-cells in
low glucose and a 28.76% (p < .05) increase in high glucose. Human single a-cells mirrored this
behavior, showing a 31.66% (p < .05) increase in Ca2+ influx in low glucose with IK channel
inhibition; while showing a 33.28% (p < .05) increase in Ca2+ influx in high glucose with IK
channel inhibition.
Summary: SK, BK and IK channels limit Ca2+ influx during conditions that stimulate a-cell
glucagon secretion. a-cell IK channel activity is unique in that it also helps to maintain glucose
induced inhibition of Ca2+ influx. Thus, KCa2+ modulation of Ca2+ influx will influence glucose
regulated glucagon secretion.
Abstract
89
AdipoRon’s differential roles in autophagy and inflammation in human aortic endothelial
cells exposed to excess nutrients
Feenalie Patel (University of Tennessee Health Science Center), Dr. Karen Weikel, Dr. Neil
Ruderman, Boston University Medical Center
The risk for cardiovascular diseases such as atherosclerosis is nearly tripled in
patients with type 2 diabetes compared to healthy individuals. The high concentrations of
circulating glucose and fatty acids that are observed in these patients have been shown to
increase oxidative stress and inflammation, and impair autophagy in vascular endothelial cells,
thus contributing to atherogenesis. Adiponectin is a circulating cytokine secreted by adipose
tissue that has been shown to attenuate nutrient-induced increases in oxidative stress and
inflammation, as well as restore autophagy. In a mouse model of diet-induced diabetes,
stimulation of adiponectin signaling using an adiponectin receptor agonist, AdipoRon, activated
AMP-activated protein kinase (AMPK) and reduced oxidative stress and inflammation in the liver,
muscle and adipose. These mice were also more insulin-sensitive and lived longer than controltreated mice.
To determine whether AdipoRon can also protect human endothelial cells from the
glucose- and fatty acid-mediated stresses associated with type 2 diabetes, we treated primary
human aortic endothelial cells (HAECs) with AdipoRon, and evaluated its effects on autophagy
and inflammation. AdipoRon increased expression of phosphorylated AMPK and acetyl CoA
carboxylase (ACC) in HAECs, confirming its role as an AMPK activator. AdipoRon also
activated autophagy in HAECs incubated in control conditions (5 mM glucose, 0 mM palmitate),
but not in HAECs incubated in media containing excess nutrients (25 mM glucose + 0.4 mM
palmitate). Interestingly, reducing glucose concentrations in the media of these nutrient-laden
HAECs restored induction of autophagy by AdipoRon, suggesting that nutrient-induced changes
in adiponectin receptor signaling may be reversible. Furthermore, AdipoRon reduced adhesion
of THP-1 monocytes to HAECs incubated in control and hyperglycemic conditions. These data
suggest that under control conditions, AdipoRon can activate AMPK, induce autophagy and
reduce inflammation in HAECs. While AdipoRon’s actions on autophagy were not observed in
the presence of excess nutrients, its anti-inflammatory actions were still observed under
hyperglycemic conditions. In addition to its previously described actions in the liver, muscle and
adipose, our data suggest that AdipoRon may also have a potential therapeutic role in the
reduction of endothelial cell inflammation and atherogenesis among type 2 diabetes patients.
Abstract
90
Assessing the Correlation between the Levels of Immunoglobulin and the Gut Microbiota
Marie G. Clancey-Rivera (Ponce School of Medicine), Changyun Hu, Li Wen, Department of
Internal Medicine, Division of Endocrinology, Yale University School of Medicine, New Haven,
CT
Obesity is a worldwide pandemic health issue with increasing prevalence in children and adults,
which is the result of the interplay between environmental factors and genetic susceptibility.
Previous studies imply that different Immunoglobulin isotypes may play different roles in dietinduced-obesity (DIO) and a higher ratio of Firmicutes/Bacteroidetes is also correlated with
obesity. Activation induced deaminase (AID) plays an essential role in generating different
immunoglobulin isotypes. To test the hypothesis that the presence of immunoglobulin affects
gut bacteria, we profiled the immunoglobulin in sera and feces samples from 1) AID-/- C57B/6
mice that were naturally delivered and reared by AID+/- C57B/6 mom and 2) AID-/- C57B/6
mice that were naturally delivered by AID-/- C57B/6 mom but fostered by C57B/6 mom.
Simultaneously, the ratio of Firmicutes/Bacteroidetes in feces samples was determined by
qPCR. The result indicated that AID-/- mice could acquire immunoglobulins from mom through
milk. Interestingly, the half life of IgG from sera of AID-/- babies from AID+/- mom (~3 week) is
longer than that of B6 mom fostered AID-/- mice (~1 week). IgM was the main immunoglobulin
detected in feces of AID-/- mice. In correlation to the immunoglobulin profile in feces, the ratio of
Firmicutes/Bacteroidetes in the feces of B6 mom fostered AID-/- mice was significantly
increased over time in comparison with AID+/- mom’s AID-/- babies. In conclusion,
immunoglobulin plays a role in high fat diet induced obesity through the modulation of gut
bacteria.
Abstract
91
The Extracellular Matrix Component Laminin α4 Modulates Insulin Secretion
Zaheen Rabbani (University of Louisville School of Medicine), Michael J. Peters, Joshua R.
Willard, Rebecca L. Hull, VA Puget Sound Health Care System and the University of
Washington, Seattle, WA
Islet endothelial cells synthesize laminin, a component of the extracellular matrix (ECM).
Laminin is a trimeric glycoprotein comprised of α, β, and γ subunits. Laminins have been
implicated in facilitating insulin release, and signal through integrin receptors expressed by β
cells. We have observed decreased expression of laminin-411 (α4, β1, γ1) in islets from diabetic
C57BL/6.db/db mice. In addition, our data show a 45% decrease in expression of laminin α4,
but no change in β1 and γ1, in islet endothelial cells cultured in high glucose. Signaling of the
trimeric laminin glycoprotein requires binding of its α subunit to cell-surface integrins. Thus, we
hypothesize that decreased laminin α4 expression by islet endothelial cells may contribute to
decreased glucose-stimulated insulin secretion, as seen in type 2 diabetes.To test our
hypothesis, immortalized mouse islet endothelial MS-1 cells were transfected with siRNA
specific for laminin α4 (lamα4-i; 0.1 - 20 nM), scrambled oligonucleotide control (scr; 10 nM) or
untreated control (n=3 for all conditions). We collected RNA and pre-conditioned media (CM)
from our MS-1 cell cultures. mRNA levels of laminin-411 subunits (α4, β1 and γ1) were
measured using quantitative PCR, normalized to the housekeeping gene cyclophillin and
expressed relative to untreated control. C57BL/6 mouse islets were exposed to CM-lamα4-i or
CM-scr for 48 hours, after which basal and glucose-stimulated insulin secretion were measured
(n=1). A dose-dependent knockdown of laminin α4 was observed in lamα4-i-treated MS-1 cells,
with 10 nM lamα4-i resulting in a 65% decrease of laminin α4 expression relative to scr (0.2±0.1
vs. 0.7±0.1; n=3, p=0.09). In contrast, laminin β1 mRNA was not changed (0.9±0.2 vs. 0.7±0.2)
while laminin γ1 mRNA was somewhat decreased (0.7±0.1 vs. 1.1±0.1). Exposure of islets to
CM-lamα4-i resulted in an approximately 33% reduction in glucose-stimulated insulin secretion
relative to CM-scr.Based on these findings, we conclude that laminin α4 may be necessary for
normal glucose-stimulated insulin secretion. Thus, decreased laminin α4 in the islet could
contribute to impaired insulin secretion in type 2 diabetes. Furthermore, increasing islet laminin
α4 in type 2 diabetes could be a therapeutic approach to improve β-cell function.
Abstract
92
Changes in measures of physical function in obese type 2 diabetes patients after Rouxen-Y gastric bypass surgery vs. intensive diabetes and weight management: results of
the SLIMM-T2D study
Jennifer Panosian (Tufts University School of Medicine), Su-Ann Ding, M.D., Donald C.
Simonson, M.D., M.P.H., Sc.D., Florencia Halperin, M.D., Marlene Wewalka, M.D., Kathleen
Foster, R.N., Katherine Kelly, B.A., Ann Goebel-Fabbri, Ph.D., Osama Hamdy, M.D., Ph.D.,
Kerri Clancy, R.N., David Lautz, M.D., Ashley Vernon, M.D., Allison B. Goldfine, M.D., Joslin
Diabetes Center
Physical activity is an integral part of diabetes and weight management, however changes in
physical functioning post-bariatric surgery compared with lifestyle education and group training
is not well understood. This sub-analysis of the SLIMM-T2D trial seeks to compare measures of
physical function in obese patients with type 2 diabetes who receive either Roux-en-Y gastric
bypass (RYGB) or intensive medical diabetes and weight management (IMWM).
We randomized 38 obese T2D (15 male / 23 female; BMI 36.3±3.4 kg/m²; age 52±6 yrs; HbA1c
8.5±1.3%) to RYGB (n=19) or IMWM (n=19). Changes in self-reported physical activity, health
status (SF-36), impact of weight on quality of life (IWQOL), and 6-minute walk test metrics were
recorded. After 2 years, RYGB had substantially greater weight loss and lowering of HbA1c,
blood pressure, and lipids than IMWM. Self-reported exercise increased early in the IMWM
group but was not sustained, while both cohorts improved to a similar magnitude at 2 years.
Changes in SF-36 physical health did not differ between RYGB and IMWM at 2 years, however
both were similarly improved from baseline at this time point. IWQOL total and its major
component sub-score of physical function improved more in RYGB after 2 years, and this
change in IWQOL directly related to greater weight loss. 6 minute walk test distance and oxygen
saturation increased similarly in both groups at 2 years, while RYGB had greater reduction in
pulse 1 minute after physical exertion. Pooled data between the groups revealed significant
correlation between change in weight and heart rate recovery at 12 and 18 months postintervention. Both RYGB and IMWM produce improvements in self-reported and quantitative
measures of physical function and perception of physical health at 2 years. Weight lossassociated improvements in quality of life measures and cardiovascular fitness should be
considered when assessing medical and surgical options for weight loss and glycemic control.
Abstract
93
Identifying new targets for β-cell regeneration using MEN1 as a model
Nohemy Morones (Columbia University), Chester E. Chamberlain, PhD, University of California,
San Francisco
Patients with Type 1 and Type 2 diabetes have decreased beta cell mass, and ultimately need
some form of beta cell replacement. One strategy to meet this need is to identify proteins that
can be targeted to drive the proliferation of insulin-producing beta cells. Multiple Endocrine
Neoplasia Type 1 (MEN1) is a rare autosomal dominant cancer syndrome characterized by beta
cell tumors and other endocrine tumors derived from the pancreas, pituitary gland and
parathyroid glands. Most MEN1 patients inherit a loss of function mutation in the MEN1 gene
that encodes for the protein menin, which suppresses beta-cell proliferation. However, about
10% of MEN1 patients lack mutations in MEN1 and the causative gene remains unknown. We
therefore hypothesized that these patients inherit a mutation in a gene other than MEN1 and
that this gene also functions to suppress the proliferation beta cells and related MEN1 endocrine
cell-types. To test this hypothesis, we performed next-generation exome-sequencing on
genomic DNA isolated from four patients who have extreme MEN1 (endocrine tumors in all
three MEN1-sensitive tissues: the pancreas, parathyroid and pituitary) but lack mutations in the
MEN1 gene, and analyzed the data to determine whether these patients shared a common
gene nullifying insertion/deletion mutation (indel). Of the 42,000 mutations identified, we found
less than 20 frameshifting indels to be common in all four patients. We are continuing to analyze
these genes and are developing a method based on CrispR technology to test the function of
these genes in beta cell proliferation using human islets.
Abstract
94
The Epigenetics of Childhood Obesity
Kathryn Tully Oelsner (Medical University of South Carolina), Yan Guo, Holli Dilks, Shari Barkin
MD, Vanderbilt University Medical Center
Epigenetics is emerging as a lens to view physiologic changes related to obesity. Recent
research identifies potential methylated candidate genes linked to specific biologically plausible
mechanisms associated with increased adiposity. This proof of principle study compared DNA
methylation in 92 saliva samples between Latino preschool children of normal weight mothers
(BMI <25 and WC <90 cm) vs children of obese mothers (BMI >30 and WC >100 cm) using a
candidate gene approach. After methodic selection, candidate genes were categorized by
biological mechanism and labelled by the impact of the promoter methylation on the
downstream mechanism to better quantify the impact of methylation on each potential
obesogenic pathway. These samples were run using the Illumina HumanMethylation Beadchip
450K and analyzed using linear regression model, differential methylation, and pathway
analysis. We hypothesized that Latino children of normal weight mothers versus those of obese
weight mothers would show differential methylation patterns at candidate gene sites, reflective
of their phenotypic adipocyte storage, hormone regulation, chemical balance, and other
potential regulators of weight gain. 119 CpG probes and 4 genes (MTL5, XKR9, FAM7A2;
FAM7A1, MAP6D1) had a significant effect change after stratification, using maternal BMI as
the predictor and differential methylation as the outcome (padj value <.05). Other genes linked
to an obesogenic trajectory (SEC14L2, TRIM61, NUDT4, APOL4, NUAK1) were differentially
methylated in children born of normal weight mothers versus those born of obese weight
mothers in quartile differential methylation analysis (p<0.025). Utilizing an obesogenic scoring
protocol to assess the impact of methylation upon the functionality of the downstream product
and overall physiologic mechanism, differential DNA methylation in genes involved with lipid and
cholesterol metabolism was identified as the most impactful upon Latino preschool obesogenic
trajectory. Utilizing saliva, a practical human tissue to obtain in naturalistic settings and in
pediatric populations, was confirmed to be a viable medium for epigenetic testing, although not
identical to results yielded from placenta. Comprehensive epigenetic analysis taking
functionality into account has not yet been utilized in previous literature, so this scoring
mechanism can be used as a model in future studies to yield relevant, comprehensive
information from epigenetic analysis.
Abstract
95
Differential Effects of Gastric Bypass versus Adjustable Gastric Banding on Body
Composition Changes in Obese Subjects
Puja Rai1 (University of Connecticut School of Medicine), Blandine Laferrère MD2, Roxanne
Dutia PhD2
New York Obesity Research Center, Columbia University Medical Center, New York, NY.
Introduction: Laparoscopic Roux-en-Y gastric bypass (GBP) and adjustable gastric banding
(AGB) are 2 commonly performed bariatric surgeries to treat obesity and induce significant longterm weight loss. Evidence suggests that GBP leads to more favorable weight loss and
metabolic outcomes over AGB. The aim of this study was to compare the effect of GBP and
AGB on body composition changes in subjects with obesity and type 2 diabetes, using a novel
3-dimensional photonic scanner (3DPS) technology.
Hypotheses: GBP results in greater weight loss and fat loss than AGB, as well as greater
reduction in waist circumference and torso volume, after adjusting for differences in weight loss.
Reduction of fat mass is correlated with improved insulin sensitivity.
Methods: Subjects were studied before and 12 months after GBP and/or after 20% weight loss
following AGB. Body composition data was collected using the 3DPS and insulin sensitivity was
assessed using HOMA-IR values.
Results: At baseline, GBP patients (n=18) were similar in age, weight and BMI compared to
AGB patients (n=9). GBP induced significantly greater weight loss compared to AGB
(31.3±6.1% vs. 18.4±10.3%, P<0.01). After adjusting for differences in weight loss, GBP
resulted in a greater reduction in fat mass (40.4±13.5% vs. 32.0±13.8%, P=0.04) compared to
AGB. Although GBP lead to a greater decrease than AGB in waist girth (24.0±6.9% vs.
14.9±7.2%, P=0.66) and torso volume (36.2±8.2% vs. 23.0±11.2%, P=0.98), these changes
were not statistically significant. The association between percent loss in fat mass and percent
decrease in HOMA-IR was stronger in AGB compared to GBP, although not significant
(R2=0.355, P=0.12 vs. R2=0.041, P=0.47).
Conclusions: GBP has more favorable effects on weight loss and results in greater fat mass
reduction compared to AGB. However, once adjusting for weight loss differences, GBP did not
cause a significantly greater reduction in other body composition parameters. The improvement
in insulin sensitivity may not only be driven by loss in fat mass after GBP. 3DPS is a novel tool
which has the potential to play a vital role in future studies to monitor and evaluate regional
body composition changes in individuals with severe obesity that undergo bariatric surgery.
Abstract
96
Increase in plasma FGF19 levels is dependent on weight loss method and independent of
percentage weight loss.
Elizabeth Hoover (University of Iowa Carver College of Medicine), Gerardo Febres, Irene M.
Conwell, Donald J. McMahon, Clifton Jackness, Wahida Karmally, Leaque Ahmed, Marc
Bessler, and Judith Korner, Columbia University Medical Center
Fibroblast growth factor 19 (FGF19) is a hormone secreted in the ileum postprandially in
response to the binding of bile acids to the Farnesoid X receptor. FGF19 treatment in high-fat
diet or ob/ob mice reduces body weight and improves insulin sensitivity. Decreased levels of
FGF19 have been noted in humans with obesity or type 2 diabetes mellitus (T2DM) with an
increase in FGF19 in the fasted and postprandial states following Roux-en-Y gastric bypass
(RYGB) surgery. It remains unknown whether this increase, which has been proposed as a
mechanism for improvement in glycemia after RYGB, is secondary to weight loss or to the
altered nutrient transit specific to the bypass procedure. The objective of this study was to
evaluate the effect of different methods of weight loss on levels of FGF19 in obese individuals
with and without T2DM after equivalent percentage of weight loss (7.9 ± 0.3%). Weight
reduction was achieved by RYGB (n=24), vertical sleeve gastrectomy (SG, n=10), or calorie
restriction (CR, n=28); each cohort included individuals with and without T2DM. Within the
calorie restriction group, subjects either underwent laparoscopic adjustable gastric banding
(LAGB, n=7) or followed a low-calorie-diet (LCD, n=21). Levels of FGF19 were quantified in the
fasted state before and after weight loss. FGF19 increased significantly in subjects who
underwent RYGB (97 ± 9 to 142 ± 9 pg/mL; P=0.0016) and SG (100 ± 14 to 179 ± 14 pg/mL;
P=0.0005) but not in subjects who lost weight via CR (102 ± 9 to 115 ± 9 pg/mL; P=0.31).
Across all interventions, baseline FGF19 levels did not differ based on T2DM status (P=0.99),
but after weight loss subjects with T2DM had a blunted increase in FGF19 levels compared to
subjects without T2DM, although this was not statistically significant. These data suggest that
the increase in plasma FGF19 levels following weight reduction is independent of percentage
weight loss and unique to anatomical alteration. This may further implicate FGF19 in the
improvement in glycemic control commonly seen after RYGB and SG.
Abstract
97
Integration and Utilization of Peer Leaders for Long-Term Diabetes Self-Management
Support: Are Healthy Behaviors Associated with Improved A1C
1
Mary Rockas, BS and 1Gretchen A. Piatt, PhD, MPH
1
University of Michigan Medical School
Evidence demonstrates that diabetes self-management education (DSME) is effective at
decreasing diabetes-related complications, including micro and macrovascular disease, in part
due to behavior changes that help lower A1C. However, certified diabetes educators are scarce
and the effects of DSME are not sustainable in the long-term without ongoing self-management
support programs (DSMS). Implementing Peer Leader (PL) led DSMS represents one possibility
for helping people with diabetes to manage their A1C levels and make behavior changes.
Therefore, we determined whether a PL DSMS model was as effective in achieving and
maintaining improvements in glycemic control and behavior change following a DSME and
DSMS intervention compared to a traditional DSME support model in 6 rural primary care
practices in Pennsylvania. Additionally, we examined whether making a behavior change was
associated with improved glycemic control over time. Practices and eligible participants (n=221;
mean age: 63.0 years, 63.8% female, 96.8% Caucasian, 28.5% at or below poverty level,
32.5% using insulin, A1c ≥ 7%: 54.2%) were randomized to the intervention (DSME+PL SMS;
n=119) or usual care (UC) group (DSME+traditional DSME support with no PL; n=102). Each
intervention practice had one PL to support participants. Behavior change was defined as
change in eating differently, eating less, eating less fat, eating less sugar, eating more
vegetables, drinking less pop/juice, and increasing physical activity. Data were collected at
baseline, 6 weeks, and 6 and 12 months. Marked decreases in A1c were observed in both
groups following DSME (intervention: -0.24%, p<0.0001; UC: -0.31%, p=0.01); however, as
SMS continued over time, intervention participants’ average A1c levels continued to significantly
decrease at 6 months (-0.32%, p=0.04) and at 12 months (-0.37%, p=0.02) in comparison to UC
which had increases in average A1c during the support period (6 months: +0.08%, p=0.09; 12
months: +0.02%, p=0.13). Greater than 80% of participants in both groups who made a
behavior change at baseline maintained the behavior change at each follow-up time. When the
association between behavior change and A1C was examined at each time point, healthy
behaviors were associated with lower mean A1C. At baseline, average A1c in the intervention
group was 8.1% for participants who ate less fat compared to 7.3% for those who did not eat
less fat (p=0.04). Similar results were observed for eating less sugar (p=<.001) and eating more
vegetables (p=0.04). In the UC group, significant associations were observed between A1c and
physical activity (baseline: p=0.03, 6 weeks: p<0.001, 12 months: p=0.04), but not eating
behaviors. These data demonstrate that PL DSMS is as effective as traditional DSME support in
helping participants to maintain glycemic control and increase healthy behaviors in the longterm. In addition, lower mean A1c was associated with improvements in healthy eating behavior
in the intervention group and physical activity in the UC group. These differences in associations
may reflect provider site bias toward encouraging patients to change eating rather than physical
activity and vice-versa. Future work will focus on examining factors, such as psychosocial
outcomes, that may mediate the relationship between behavior change and glycemic control.
Abstract
98
The Acute Phase Response in Total Joint Arthroplasty: is it predictable, consistent, and
respective?
William K. Oelsner Jr. (Medical University of South Carolina), Thomas J. An, Michael A.
Benvenuti, Richard A. Jacobson, Gregory Polkowski MD, Jonathan G. Schoenecker MD PhD,
Vanderbilt University
Total joint arthroplasty is a major orthopedic surgery that has a high risk of postoperative
thromboembolic events as a result of the acute phase response (APR). In response to tissue
injury, fibroblasts, endothelial cells, keratinocytes, and monocytes release Interleukin-6 into
circulation which induces the APR in the liver to release pro-coagulant factors and inflammatory
metabolites including fibrinogen and C-reactive protein (CRP).1 D-dimer, a degradation product
of plasmin and fibrin (a product of fibrinogen and thrombin), is a key biomarker for ongoing clot
formation and fibrinolysis.2 Although the APR is essential for preventing bleeding and infection,
a prolonged APR and coagulation imbalance can lead to life-threatening hemorrhage, wound
hematoma, poor wound healing, deep venous thrombosis, pulmonary embolus, and
disseminated intravascular coagulation if the APR is not resolved.3 Our hypothesis is that the
APR response to a specific surgery is predictable, consistent, and respective for total joint
arthroplasty. Lab values were retrospectively studied in 76 patients undergoing total knee
arthroplasty (TKA) and 43 patients undergoing total hip arthroplasty (THA) by a single surgeon.
Samples where measured pre-op, post-op day 1 to 4, 2 weeks post-op, and 6 weeks post-op.
CRP had a 38.6 fold increase and peak on post-op day 2.796 +/- 3.213 for TKAs and a 20.2 fold
increase and peak on post-op day 1.840 +/- 0.5360. Fibrinogen had a 1.6 fold increase and
peaked on post-op day 6.135 +/- 8.711 for TKAs and a 1.5 fold increase and peak on post-op
day 7.583 +/- 7.937 for THAs. D-Dimer had a 6.3 fold increase and peak on post-op day 5.675
+/- 3.031 for TKAs and a 6.0 fold increase and peak on 13.81 +/- 5.075 for THAs. CRP and
Fibrinogen levels were resolved by week 2 and week 6 respectively, while D-Dimer was
unresolved by week 6. Furthermore, resolution, as measured by the time from peak value to
half-maximum value, was not statistically different between the TKA and THA cohorts for CRP
and Fibrinogen. There was statistical difference between D-Dimer resolutions for the cohorts.
Increased pre-operative CRP levels correlated with increased max Fibrinogen levels for TKAs,
(p=0.0183, Spearman r = 0.3063) and for THAs (p= 0.0087, Spearman r = 0.4252). Increased
pre-operative fibrinogen correlated with increased max CRP for TKAs (p=0.0013, Spearman
r=0.3769). Pre-operative blood glucose levels correlated with max D-dimer depression (p=
0.0226, Spearman R = -0.2940) for TKAs but not for THAs. In conclusion, total joint
arthroplasty demonstrated a consistent APR for both TKAs and THAs. The acute phase
reactants had specific, unique temporal peaks and intensities which were not significantly
different between cohorts. This data suggests that total joint arthroplasty induced APR is
consistent and predictable for a non-Gaussian distribution of patients with few comorbidities and
adverse outcomes. For this reason, future investigations into the APR for Gaussian
distributions are merited: if the APR is predictable and consistent for patients with good
outcomes as well as those with adverse outcomes, then it would allow clinicians to predict and
treat before and during post-operative, APR complications.
Abstract
99
Screening for Diabetes in Routine Clinical Practice
Scott Mauch (Michigan State University College of Human Medicine), Laura N. McEwen PhD,
William H. Herman MD, University of Michigan, Ann Arbor, MI
In 1997, the American Diabetes Association recommended that diabetes screening be carried
out at 3-year intervals for all non-diabetic individuals ≥ 45 years of age, with the preferred
screening test being fasting plasma glucose. A 2004 study conducted by Ealovega et al.
described screening and follow-up in the population of non-diabetic patients ≥ 45 years of age
who utilized an academic health care system. Despite high screening rates and targeting of
patients at high-risk for diabetes, follow-up of patients with abnormal screening results was low.
The authors concluded that failure to follow-up on abnormal glucose levels was a barrier to
diagnosis and treatment. In 2009, with the addition of HbA1c as the recommended screening
test for diabetes, we hypothesized that screening, follow-up, and diagnosis of diabetes in routine
clinical practice would improve. To test this hypothesis, we studied screening in non-diabetic
patients ≥ 45 years of age enrolled in Blue Care Network (BCN), a large commercial HMO, who
were assigned to University of Michigan Health System primary care providers. Screening was
defined as the first test of glycemia performed between January 1, 2010 and December 31,
2013. Of 12,797 patients studied, 9,966 (78%) were screened. Laboratory glucose testing
accounted for 86% (n = 8,522) of all screening tests. Women were more likely than men to be
screened, and patients ≥ 65 years of age were more likely to be screened than those of lower
ages. Of 9,966 patients screened, 39% (n = 3,843) had abnormal results. These data suggest
that the addition of HbA1c as the recommended screening test has increased both the rate of
screening in the study population and the use of HbA1c as a screening method. Chart reviews
of patient medical records and BCN insurance claims to determine diabetes risk factors, rates of
follow-up, and rates of diagnosis of diabetes are currently ongoing.
Abstract 100
Genetic Variants Associated with Testosterone to Androstenedione Ratio in Polycystic
Ovary Syndrome
Melba Beltre1 (New York Medical College), Andrew Bjonnes2, Cindy Pau1, Richa Saxena2, and
Corrine Welt1
The Reproductive Endocrine Unit1, Department of Anesthesia and Center for Human Genetic
Research2, Massachusetts General Hospital, Boston, MA
The phenotypic expression of polycystic ovary syndrome (PCOS) varies among women of
different racial and ethnic backgrounds, particularly the levels of testosterone and
androstenedione. Although the cause of PCOS is not clearly defined, there is evidence for a
genetic basis. 17β-hydroxysteroid dehydrogenase type 5 (AKR1C3) and type 6 (SDR9C6) are
involved in the conversion of androstenedione to testosterone in the adrenal gland and ovary.
We tested the hypothesis that genetic variants in AKR1C3 and SDR9C6 are associated with
testosterone to androstenedione (T:A) levels. Women recruited were 1) with PCOS, according
to the NIH criteria (hyperandrogenism and irregular menses; n=294), and 2) Controls with
regular menstrual cycles and no signs of hyperandrogenism (n=252). All women were of mixed
European ethnicity in Boston, with normal TSH and prolactin, and no evidence of ovarian
insufficiency or nonclassic congenital adrenal hyperplasia. Serum testosterone and
androstenedione levels were measured using radioimmunoassay, and DNA was isolated for
genetic analysis. Genotyping was performed using the Omni Express Plus Exome Bead Chip
(Illumina). Serum T:A ratios were calculated and PLINK software was used to analyze
associations between T:A and genetic variants in the candidate genes, as well as associations
between T:A and genome-wide variants. Bonferroni corrections were applied to the p-values
which were adjusted to avoid false positive associations from multiple testing. The candidate
gene analysis did not show a significant correlation between variants in AKR1C3 (p>6x10-5) and
SDR9C6 (p>2x10-4) and T:A ratios. The genome-wide analysis showed one SNP with a
significant association (p<4x10-9). The SNP, rs9323945, is a missense variant in the ATG2B
gene, resulting in a change from asparagine to aspartic acid. The amino acid is highly
conserved, although the change is predicted to be benign. ATG2B has functions in the
regulation of the metabolic profile and the association may indicate a relationship with
androgenic or other phenotypic features of PCOS. The study will need to be replicated in an
additional population. The data suggest that more genetic studies are needed to further assess
the correlation between androstenedione and testosterone levels and SNP associations in
PCOS.
Abstract 101
Gender and income level influence dietary habits of African-Americans.
Ronald R. Magee Jr. (The Warren Alpert Medical School of Brown University), Dr. Jessica Yeh,
PhD; Dr. Pete Miller, PhD, MD; Johns Hopkins School of Medicine
The relationship between diet and diabetes has fueled a number of recent studies,
especially with regard to the interplay between the two and other societal factors within minority
and disadvantaged communities. In this study, we examine the diets of an inner-city AfricanAmerican cohort to test the following three hypotheses: 1) adults with diabetes have better
adherence to an advantageous diet than those without diabetes, 2) diabetic women have better
adherence to a nutritious diet than men, and 3) higher socioeconomic status is positively
correlated with adherence to advantageous dietary guidelines. Adherence to a DASH-OMNI diet
and general nutritional guidelines prescribed by the United States Department of Agriculture
(USDA) and United States Department of Health and Health Services (USDHHS) was
measured from data acquired through a self-administered Block Fruit/Vegetable/Fiber screener
and Block Dietary Fat Screener. Statistical analyses were arranged by diabetes status, gender,
and yearly household income. 123 African Americans with controlled hypertension were
included in the study, including 89 people with diabetes and 34 people without diabetes. Among
individuals without diabetes, we found that women and people of lower socioeconomic status
displayed statistically significantly greater adherence to USDA guidelines than men and people
of higher socioeconomic status, respectively. Non-diabetics of higher socioeconomic status, on
average, ate daily 10.92 more grams of fat (P=.04), 5 more grams of saturated fat (P=.01), and
47.39 more milligrams of cholesterol (P=.01) than their lower income counterparts. Non-diabetic
men, on average, daily ate 5.13 more grams of saturated fat (P=.0099) and 69.05 more
milligrams of cholesterol (P=.0001) than their female counterparts. The results of this study
suggest that gender and income are associated with adherence to a health-maintaining diet in
African Americans. The results of this study could have implications for designing a clinical diet
therapy and nutritional diabetes prevention for inner city minority populations.
Abstract 102
Impaired TUG protein proteolysis in insulin resistant adipose tissue.
Muyi Li (Medical University of South Carolina), Estifanos Habtemichael, Don Li, Max Petersen,
Gerald Shulman, Jonathan Bogan, Yale University.
Insulin stimulates glucose uptake in adipose and muscle by triggering proteolytic cleavage of
TUG proteins. In unstimulated cells, TUG sequesters GLUT4 glucose transporters intracellularly.
Cleavage releases GLUT4 for translocation to the plasma membrane to increase glucose
uptake. During the pathogenesis of type 2 diabetes, GLUT4 translocation is impaired, resulting
in insulin resistance. Here, we tested the hypothesis that impaired TUG proteolysis contributes
to impaired GLUT4 translocation in adipose tissue of insulin resistant rats. To induce insulin
resistance, animals were fed a high-fat+sucrose diet for three days. Control and insulin-resistant
rats were fasted, treated with or without a 20-minute infusion of insulin and glucose, and then
sacrificed. Adipose tissue was harvested and protein lysates were immunoblotted to detect TUG.
In control rats, insulin caused a decrease in the abundance of intact TUG protein to 43±7% of
the abundance observed in fasting animals (p<0.05, n=4 in each group). In insulin resistant rats,
this decrease was not observed, and TUG abundance was unaffected by insulin stimulation.
These results indicate that TUG proteolysis was impaired in white adipose tissue of insulin
resistant rats, compared to controls. Because TUG cleavage is independent of canonical insulin
signaling through phosphatidyl-3-kinase to Akt, the data imply that diet-induced insulin
resistance results in part from impairment of other pathways. Thus, the data reveal a novel
mechanism for diet-induced insulin resistance, which may contribute to the development of type
2 diabetes.
Abstract 103
Identifying novel antigenic targets and role of antigen modification for BDC-2.5 T cells in
type I diabetes
Juliana Xie (Penn State College of Medicine), Martin Thelin, and Tom Serwold. Research
conducted at Joslin Diabetes Center, Boston.
BDC-2.5 T cells are a T cell clone developed from nonobese diabetic (NOD) mouse that reliably
induces autoimmune pancreatitis and have been used extensively in type I diabetes research.
However, the identity of the autoantigen that these BDC-2.5 T cells specifically react to has
remained elusive. More than 20 years later, in 2010, a candidate autoantigen called
chromogranin A, had finally emerged. Interestingly, follow-up studies have shown that posttranslationally modified version of chromogranin A transfers autoantigenic. This is achieved by
an enzyme called transglutaminase. These two important observations drive the two
hypotheses in this study: 1) Transglutaminase modifies chromogranin A, making it autoantigenic
to BDC-2.5 T cells; 2) Besides chromogranin A, there are other autoantigenic targets of BDC2.5 T cells. To test hypothesis 1, we aimed to co-express chromogranin A and transglutaminase
in both the fibroblast and the NIT cell (pancreatic beta cells from NOD mice) systems. These
cells are then co-cultured with BDC-2.5 splenocytes, and then assayed for the level of IL-2
cytokine production via ELISPOT (as a measure of T cell stimulation). To test hypothesis 2, we
aimed to express seven novel pancreatic genes (individually) in both fibroblasts and NIT cells,
then test for their ability to stimulate T cells by co-culturing with BDC-2.5 T cells, then IL-2
ELISPOT assay. During experimentation, three of the seven candidate genes were cloned and
expressed in fibroblasts and NIT cells with success. These were chromogranin A, chromogranin
B, and secretogranin 3, and they are components of secretory granules in pancreatic beta cells.
Results (qualitative; quantitative to come): chromogranin A+-NIT cells induced higher number of
spots in the ELISPOT assay than control NIT cells, while no significant difference was observed
in chromogranin A+-fibroblasts versus control fibroblasts. There was no observable difference in
the number of spots in chromogranin B+ and secretogranin 3+ cells when compared with their
respective controls. Therefore, we conclude that chromogranin A is likely the epitope for BDC2.5 T cells, and that an unknown mechanism of post-translational modification specific to NITcells is at work to render the peptide more antigenic to BDC-2.5 T cells.
Abstract 104
Association of Physical Activity Between Children and Their Mothers
April Venn, Maciej Buchowski, PhD
Dartmouth Geisel School of Medicine & Division of Gastroenterology, Hepatology & Nutrition,
Department of Medicine Vanderbilt University Medical Center
Obesity is a rapidly growing epidemic in the US population affecting both adults and children
that is thought to be caused by genetic and environmental factors. Our study explored some
environmental factors by looking at the energy expenditure, physical activity, BMI and percent
body fat of 21 children and their mothers to see if there was an association among energy
expenditure, physical activity and BMI. Based on maternal influences and control over a child’s
activities we hypothesized that a child’s physical activity level and time spent in sedentary
behaviors and performing physical activity of various intensities would be similar to their
mother’s. The participants had Actigraph accelerometers placed on their waists. The Actigraph
recorded their physical activity (PA) in the free-living environment for a week. The PA was
categorized as sedentary, low, moderate or vigorous intensity. Children and their mothers
showed a moderate correlation in their total energy expenditure during low intensity PA. Weak
correlation existed between total energy expenditure of children and their mothers in other
activity levels. Mothers spent 81.6 % of their time sedentary, while children spent 75.3% of their
time sedentary. Mothers spent 18.4 % of their time in low, moderate or vigorous physical activity.
Children spent 24.7% of the time in low, moderate or vigorous physical activity. Overall the data
showed a weak to moderate correlation between children and their mothers for energy
expenditure, time spent performing various activities and total physical activities. Weak
correlations were seen between BMI, body fat and total physical activity. The small sample size
did not allow us to definitively assess the strength of the effects of these associations. Larger
studies are needed to make stronger conclusions about the association among BMI, body fat,
physical activity and energy expenditure between children and their mothers.
Abstract 105
Volumetric brain changes detected over time in association with hypo- and
hyperglycemia in youth with type 1 diabetes mellitus (T1DM)
Sneha Thakur (New York Medical College), Heather Lugar, Tasha Doty, Amal Al-Lozi, Jonathan
Koller, Neil White, and Tamara Hershey, Washington University in St. Louis
Severe hypoglycemia, severe hyperglycemia, and chronic hyperglycemia in children and adults
with type 1 diabetes mellitus (T1DM) have been associated with cross-sectional structural brain
differences in magnetic resonance imaging (MRI), but it is unclear how and when these
differences emerge. We performed a 2 year longitudinal structural MRI study on youth with
T1DM and their non-diabetic siblings, examining their rates of change in subcortical and whole
brain volumes. Previous analyses of these data used a voxel-wise approach that required
multiple comparison corrections for all voxels. We sought to confirm and possibly reveal new
findings by using Freesurfer’s established longitudinal processing stream which applies a
different registration algorithm to anatomically define and measure volume in brain regions in
individuals. Our analyses revealed that non-diabetic controls showed a greater increase in
volume over time than T1DM youth in the brainstem (p=.045) and nucleus accumbens (p=.045).
Within T1DM youth, we found significant differences in rates of volumetric change between
T1DM youth exposed to hypoglycemic episodes (hypo) and chronic hyperglycemia (hyper)
between time points (p’s<.05). Specifically, T1DM youth with any hypos between time points
were associated with a smaller rate of increase in both cerebellar white (p=.016) and total
cortical white matter volume (p=.031) over time than those with no hypos. Additionally, T1DM
youth with chronically high hyperglycemia (mean A1c>9.0%) between time points showed a
greater rate of decrease in total cortical gray matter volume than T1DM youth with mid (mean
A1c=7.5-8.9%) or low (mean A1c<7.5%) hyper exposure (p=.001 and p=.003), or controls
(p=.014). The high hyper exposure group also showed smaller rates of increase in corpus
callosum volume than those with mid hyper exposure (p=.003) and controls (p<.001), while the
low hypo exposure group showed a smaller rate of increase in corpus callosum volume than did
controls (p=.041). Our findings complement previous VBM analyses by showing that exposure
to glycemic extremes in T1DM youth was associated with suppressed white matter growth over
as little as 2 years, and hyper exposure had the added effect of greater gray matter loss in the
cortex but not in the subcortex. Further, we found novel volumetric changes over time in
subcortical regions of T1DM youth compared to their non-diabetic controls. Our results may
suggest that poor glucose control in the developing brains of T1DM youth is associated with
decreased myelin growth (white matter) and increased neuronal pruning (gray matter).
Abstract 106
Finding a Cause for Neonatal Diabetes
Katherine Lindauer (Michigan State University College of Human Medicine), Graeme I. Bell,
David Carmody, Siri Atma W. Greeley, University of Chicago Kovler Center for Diabetes
Research
When diabetes is diagnosed in patients younger than one year of age a genetic, rather than
autoimmune, cause is often attributed to their high blood sugars. While there are currently
several known causative genes, there are still many patients whose causative genetic variants
have yet to be identified, and new gene-based etiologies must be sought. Based on an early
diabetes diagnosis and the presence of other autoimmune symptoms, we hypothesized that six
patients in the Monogenic Diabetes Registry were good candidates for testing of a causative
variant in STAT3, a newly suspected causative gene that has been previously implicated in
various forms of cancer. We also hypothesized more generally that patients in our registry were
more likely to have an identifiable mutation if they received their diabetes diagnosis when they
were less than six months of age. We used the University of Chicago’s Monogenic Diabetes
Registry to a) select patients as STAT3 testing candidates and b) track genetic causes for all
patients diagnosed at less than one year of age. DNA samples from the patients who were
candidates for STAT3 testing were sent to the University of Exeter for sequencing. This testing
is ongoing, but its results will determine whether these patients are at higher risk for having
other autoimmune conditions in the future. If the results come back positive, that will also
indicate that alterations in the sequence of STAT3 are causative of diabetes for these patients.
In addition to the results concerning STAT3, we found that among all patients in the registry,
individuals were more likely to have a known causative variant if they were diagnosed with
diabetes when they were less than six months old; and that among these, mutations in the
potassium channel gene KCNJ11 were most common.
Abstract 107
Examining the role of β-oxidation in fatty acid-induced IRE1α signaling and NLRP3
inflammasome activation
Herodes Guzman (University of North Carolina School of Medicine), Megan Robblee and Suneil
Koliwad, University of California, San Francisco
In obesity and type 2 diabetes, adipose tissue macrophages are exposed to excess fatty
acids which have been shown to induce inflammatory activation and ER stress. Activation of
the ER stress sensor IRE1α in macrophages treated with saturated fatty acids (SFAs) has been
linked to the activation of the NLRP3 inflammasome, leading to the secretion of the cytokine IL1β. Recent studies link IRE1α activation to changes in ER membrane composition, suggesting
that altering fatty acid flux to phospholipids may modulate SFA-induced IRE1α activation. We
hypothesized that inhibition of fatty acid β-oxidation with etomoxir would potentiate SFA-induced
IRE1α signaling and subsequent NLRP3 inflammasome activation. The efficacy of etomoxir
was confirmed with the Seahorse Biosciences XF Analyzer, as the oxygen consumption rate of
fatty acid-treated bone marrow derived macrophages was decreased in the presence of
etomoxir. Etomoxir was found to heighten IRE1α activation in response to the SFA stearate, as
measured using a luciferase reporter. This suggests that inhibiting beta-oxidation may divert
SFAs to metabolic pathways that lead to IRE1α activation. Contrary to the potentiation of the
SFA-induced IRE1α, etomoxir did not affect stearate-induced IL-1β secretion but unexpectedly
reduced the secretion of IL-1β in response to another SFA, palmitate. These data suggest that
blocking β-oxidation may affect NLRP3 inflammasome activation in a fatty acid-specific and
IRE1α-independent manner.
Abstract 108
Characterization of iPS cells for Wound Healing in Diabetic Patients
Lourdes Ramirez (University of Central Florida), Mogher Khamaisi, M.D., Ph.D.; George L. King,
M.D. Joslin Diabetes Center, Harvard Medical School, Boston, MA
Background: Impaired wound healing is the most frequent cause of hospitalization in diabetes
patients, often characterized by the development of diabetic foot ulcers, which precede 84% of
diabetes-related lower extremity amputations. Many complex pathophysiological mechanisms
involved are still unknown. The development of human inducible pluripotent stem cells (hiPSc)
by reprogramming of somatic cells to a self-renewing and pluripotent state, has led to the
potential for new treatment modalities in impaired wound healing and regenerative medicine.
The aim of this study is to characterize hiPSc derived from Type 1 diabetic patients as
compared to age-matched healthy controls in parameters significant in wound healing, namely,
cell adherence, proliferation and VEGF production. The hypothesis of the study is that hiPSc
derived from diabetic patients have reduced adhesion, proliferation, and VEGF expression in
comparison to healthy controls.
Methods: Three cell lines were used in this study: one hiPSc line derived from a 78 year-old
healthy male control and two hiPSc lines (89 year-old male with 85-year duration of diabetes,
and 66 year-old male with a 51-year duration of diabetes). To measure adhesion and
proliferation, hiPSc were harvested after incubation for 1 h (adhesion), or every 48 h followed for
up to 8 days after seeding (proliferation). VEGF mRNA levels were obtained by qRT-PCR after
hiPSc stimulation by insulin (100 nM) and hypoxia (5% O2) for 24 h. mRNA results were
corrected in comparison to human b-Actin house-keeping gene.
Results: Cell adhesion is reduced in diabetic hiPSc to 56.2% and 43.6% from that seen in the
healthy control hiPSc. VEGF mRNA expression is impaired in diabetic hiPSc (3.1 and 3.03-fold
increase from basal conditions) following insulin stimulation in comparison to healthy controls
(16-fold increase). VEGF mRNA levels in diabetic hiPSc increased 2.15 and 2.36-fold from
basal conditions following hypoxia stimulation, but further work with the control is required for
conclusions. Preliminary data suggest reduced proliferation rate in diabetic hiPSc compared to
healthy controls, however, an increased sample size is necessary to measure significant
differences.
Summary: This study suggests that diabetic hiPSc show impaired phenotypes related to wound
healing when compared to healthy hiPSc controls. Furthermore, diabetic hiPSc retain some of
the impaired characteristics observed in the fibroblasts from which they were derived.
Conclusion: These findings contribute to the long-term end-goal of developing therapies where
transplantation of hiPSc, with defects corrected, into diabetic wounds may be used as a novel
cell-based strategy for wound healing in diabetic patients
Abstract 109
Initial evidence that hypothalamic injury is associated with obesity and insulin resistance.
Zenobia Gonsalves (Chicago Medical School at Rosalind Franklin University of Medicine and
Science), Susan J Melhorn, Mary K Askren, Vidhi Tyagi, Kenneth R Maravilla, Ellen A Schur;
University of Washington
In both rodent models and humans, obesity is associated with evidence of gliosis in the
mediobasal hypothalamus (MBH), a region critical for energy balance, regulation of body mass
and glucose homeostasis. Gliosis in the central nervous system (CNS) occurs in response to
neuronal injury and is characterized by the recruitment, activation and proliferation of astrocytes
and microglia. It may be detected using quantitative magnetic resonance imaging (MRI)
techniques and identified as an increased T2 relaxation time or an elevated T2 signal ratio.
Additionally, hypothalamic activity in response to an oral glucose load, measured using
functional MRI (fMRI), has been shown to be altered in obesity and type 2 diabetes. However, it
is unknown whether gliosis plays a role in this change. Therefore, two studies were
implemented to test the hypotheses that 1) radiologic evidence of MBH gliosis in humans will be
associated with obesity, insulin resistance, decreased physical activity, and eating behaviors
that promote excess food consumption, and that 2) hypothalamic activity in response to glucose
ingestion will be increased in those showing radiologic evidence of MBH gliosis. In a nested
case-control design, 21 healthy, normal-weight (BMI 18.5-24.9) or obese (BMI>30) adults (7
males, 14 females) aged 18-50 years (mean 33.5 + 12.1) had a fasting blood draw, completed
behavioral questionnaires and underwent an MRI in Study 1. Select participants from Study 1
(those with a T2 relaxation time less than 90.5 ms or greater than 95.5 ms) then completed
Study 2, a pilot study to test the second hypothesis noted above. After an overnight fast, these
subjects (n=2; 1 male, 1 female; 1 T2 relaxation time<90.5, 1 T2 relaxation time>95.5) had a
fasting blood draw, answered behavioral questionnaires and completed an oral glucose
tolerance test (OGTT) while undergoing a functional MRI (fMRI). From the 21 Study 1
participants, a group of cases with radiologic evidence of gliosis was identified as the tertile
(n=7) with the longest T2 relaxation time in the left MBH and was compared to a group of
controls identified as the tertile (n=7) with the lowest T2 relaxation time in the left MBH.
Compared to controls, cases with radiologic evidence of left MBH gliosis tended to have higher
BMIs (33.1+10.2 in cases vs. 23.7+7.3 in controls, p=0.07), a higher proportion of obese
subjects (57% in cases vs. 14% in controls, p=0.09) and lower total physical activity (2008+2621
MET-min/week in cases vs. 3305+1713 MET-min/week in controls, p=0.30). Additionally, cases
with radiologic evidence of left MBH gliosis tended to have higher fasting glucose levels
(93.9+11.3 mg/dl in cases vs. 88.7+7.1 mg/dl in controls; p=0.33), higher fasting insulin levels
(10.5+7.5 uU/ml in cases vs. 5.3+3.3 uU/ml in controls; p=0.13) and higher HOMA-IR values
(2.5+2.0 in cases vs. 1.1+0.7 in controls, p=0.12). These data lend initial evidence that
hypothalamic damage may play a role in obesity and insulin resistance and suggest that studies
showing hypothalamic gliosis in rodent models of diet-induced obesity are relevant to the
scientific understanding of obesity and insulin resistance in humans. Our current fMRI findings
indicate a noticeable difference in hypothalamic activity in response to an oral glucose load
between the two pilot study subjects. Participants will continue to be enrolled in both studies to
better understand the potential link between hypothalamic gliosis, obesity, insulin resistance and
the hypothalamic response to glucose ingestion.
Abstract 110
A systematic literature review: Diabetes self-management interventions for patients with
type 2 diabetes living in rural areas
Morgan G. Lepard, BS (University of Tennessee Health Science Center); Alessandra Joseph
(Brown University); April Agne, MPH; Andrea Cherrington, MD MPH,
University of Alabama at Birmingham
Background
Patients living in rural areas have a higher prevalence of type 2 diabetes mellitus (T2DM) than
their urban counterparts.1 Rural-dwelling patients face unique challenges and obstacles in
accessing diabetes education programs and day-to-day diabetes management.
Objective
In order to develop an effective diabetes self-management program for rural Alabamians, we
systematically reviewed the evidence for diabetes education and self-management interventions
designed for rural-dwelling patients with T2DM.
Methods
A systematic electronic search was conducted on PubMed using the keywords: rural population,
diabetes education, diabetes “self-management” education, diabetes “self-management”, and
diabetes “self-management” support. Eligible studies had to describe interventions, have
measured outcomes, occur within the last 10 years, and focus on a rural population. Studies
without a control/comparison group, study designs with N<50, or studies that did not target adult
patients with T2DM were excluded.
Results
The search yielded 1,512 abstracts. Twenty-seven studies were reviewed in their entirety and 9
studies met inclusion criteria and data abstracted. Over half were randomized controlled trials
(n=5). Intervention strategies varied: group or individual DSME programs (n=5), telehealth
interventions (n=3), and a web-based intervention (n=1). Outcomes were grouped into 3 main
categories: biologic, behavioral, and diabetes-related knowledge. Five studies reported
statistically significant outcomes (3 DSME, 1 telehealth, 1 web-based). Of the 7 studies
examining changes in HbA1c, 2 demonstrated significant improvements at 1 year (1 DSME
program and 1 telehealth program). A separate study testing a DSME intervention resulted in
significantly decreased serum glucose at 6 months. Two DSME interventions resulted in
statistically significant weight loss and reductions in BMI. Finally, a study comparing telehealth
with face-to-face sessions found that these intervention strategies produced similar
improvements in metabolic control after one year.
Conclusions
We identified a limited number of studies with rigorous study designs evaluating interventions
for rural-dwelling patients with T2DM. Effective interventions involved more patient contact
hours and a focus on DSM-related behaviors and weight management. Telehealth interventions
may produce outcomes comparable with face-to-face DSME interventions. Additional studies
are needed to identify the most efficient and effective modalities for delivery of DSME in rural
areas.
1. O’Brien T, Denham SA. Diabetes care and education in rural regions. The Diabetes Educator.
2008; 34(2): 334-347.
Abstract 111
Effect of High-Fat Diet on PKA Subunit Expression in Mice
Shriya Gandhi (University of Illinois College of Medicine – Chicago), Ronald N. Cohen, Barton
Wicksteed, University of Chicago
The cyclic AMP (cAMP) signaling pathway has been shown to regulate multiple intracellular
processes, including growth, metabolism, differentiation, proliferation, and gene transcription.
One of the main downstream effectors of this pathway, cAMP-dependent protein kinase (PKA),
plays a critical role in the mechanisms that regulate beta-adrenergic receptor-stimulated
lipolysis in adipocytes. cAMP-mediated activation of PKA leads to phosphorylation of perilipin
and hormone sensitive lipase (HSL), two proteins that are important for maintaining the balance
between lipogenesis and lipolysis within adipocytes, and likely results in many other effects as
well. The PKA holoenzyme is composed of two regulatory and two catalytic subunits. The two
classes of regulatory subunits, RI and RII, have different affinities for cAMP and show
differences in their intracellular localization. Studies with transgenic mice have demonstrated
that alterations in PKA subunit expression can change lipid deposition in different fat depots.
The aim of this study was to determine whether the expression of PKA subunits and PKA
activity is altered in response to high-fat feeding. Adipose tissue from four fat
depots―subcutaneous (SQ), mesenteric, epididymal, and brown adipose (BAT)―was
harvested from 25 week-old male mice, which had been fed either a standard chow diet or a
high-fat diet (60% fat) since weaning at 4 weeks of age. Protein and RNA was isolated from
each fat depot and characterized respectively by immunoblotting and quantitative real-time
polymerase chain reaction (qRT-PCR). SQ and BAT depots exhibited little change in protein
expression of either PKA regulatory or catalytic subunits between chow and high-fat diet.
However, in the epididymal depot, our data demonstrated an increase in PKA RIα and a
decrease in PKA RIIβ protein expression, when mice were exposed to high-fat feeding. Ongoing
studies will evaluate PKA subunit expression in mesenteric tissue, a second visceral fat depot.
Our data suggest that in the epididymal depot, high-fat feeding could induce PKA signaling to
become more reliant on the RIα subunit, which has a higher affinity for cAMP. This may cause
PKA to release its catalytic subunits at lower cAMP levels and result in increased
phosphorylation of downstream targets, possibly leading to increased rates of basal lipolysis.
Such findings may demonstrate a novel mechanism by which high-fat feeding leads to
increased free fatty acid circulation in obese individuals, a condition that has been shown to
result in increased insulin resistance and lipotoxicity in other metabolic tissues.
Abstract 112
Dietary acid load is associated with serum bicarbonate but not insulin resistance in
chronic kidney disease.
H. Omer Ikizler (University of Vermont College of Medicine), Leila Zelnick, Kristina Utzschneider,
Steven Kahn, Jonathan Himmelfarb, Ian de Boer, University of Washington School of Medicine
Chronic metabolic acidosis is a common complication of chronic kidney disease (CKD) that may
contribute to the progression of CKD and its numerous comorbidities, including increased insulin
resistance. Dietary acid load may be a modifiable risk factor in the development of metabolic
acidosis in patients with CKD. We investigated the hypothesis that dietary acid load is
associated with serum bicarbonate and insulin resistance in 49 nondiabetic patients with CKD
stages 3-5 and 15 healthy controls. Net endogenous acid production (NEAP) and potential renal
acid load (PRAL) were quantified by 3-day prospective food diaries. Insulin sensitivity was
measured by hyperinsulinemic euglycemic clamp. Mean (SD) values for NEAP, PRAL, serum
bicarbonate, and insulin sensitivity were 60.5 (30.3) mEq/day, 9.7 (18.3) mEq/day, 24.8 (2.7)
mEq/L, and 4.5 (2.2) mg/min glucose per µU/mL insulin, respectively. Both measures of dietary
acid intake were significantly associated with serum bicarbonate in analyses adjusted for age,
eGFR, sex, race, BMI, and use of diuretics. In NEAP, difference between the lowest (≤ 45.6
mEq/day) and highest (>64.2 mEq/day) tertiles was -2.0 mEq/L (95% CI -4.0, -1.0) of
bicarbonate; p = .045 for continuous exposure. In PRAL, difference between the lowest (≤ 2.21
mEq/day) and highest (> 19.1 mEq/day) tertiles was -2.0 mEq (95% CI -3.0, -0.4) of
bicarbonate; p <.001 for continuous exposure. Neither NEAP, PRAL, nor serum bicarbonate
were significantly associated with insulin sensitivity. These results suggest that modification of
dietary acid may be effective in blunting metabolic acidosis in CKD, but may not affect insulin
resistance.
Abstract 113
Understanding the role of POPDC2 & POPDC3 in colorectal epithelia
Suzanne Kissel (Indiana University School of Medicine), Mukal Mittal, Sarah Short, Benjin Facer,
Bobak Parang, Vishruth Reddy, Cody Keating, Christopher Williams.
Vanderbilt University School of Medicine, Nashville, Tennessee
Colorectal cancer (CRC) is the second most common cancer in the United States, striking
140,000 people annually and causing 60,000 deaths. The Popeye domain containing family is a
group of homologous proteins with three members identified to date: BVES (POPDC1),
POPDC2, and POPDC3. All three proteins contain both a Popeye domain as well as three
conserved transmembrane domains. BVES in particular has recently been associated with
cellular tight junctions (TJs), and is thought to be involved in regulating the association of TJ
components. Dysregulation of TJs is often associated with carcinogenesis and recent studies
support a role of TJ integral proteins in the regulation of Epithelial-to-Mesenchymal Transition, a
key feature of advanced malignancy. BVES (POPDC1) expression has been shown to be
reduced in CRC by promoter hypermethylation but the status of other family members has not
been studied. Therefore, the purpose of this research served to define the role of POPDC2 and
POPDC3 in the colonic epithelial cell and their role in CRC. First, we analyzed mRNA
expression from The Cancer Genome Atlas database to determine expression differences in the
POPDC genes between normal and CRC tissues. These data suggest [1][2]that all three genes
are downregulated significantly in cancer tissue versus normal. We further measured mRNA
expression in a variety of colon cancer cell lines, but POPDC gene expression did not obviously
correlate with cell aggressiveness or epithelial morphology. We then utilized immunofluorescent
and immunohistochemical (IHC) staining to identify the location of POPDC3 in the cell.
Interestingly, this expression appeared to be largely nuclear with varying appearance in the
cytoplasm. IHC staining of human CRCs further validated the nuclear expression observed in
vitro, yet also suggested that the POPDC3 protein expression is increased in cancer versus
normal tissue. This conflicts with mRNA data for POPDC3, yet may be due to possible posttranslational modifications or another event which impacts protein degradation. While much
work remains to be done, these studies support a role for POPDC2 and POPDC3 in colon
cancer tumorigenesis, which is likely distinct from the role of BVES. Further investigation will be
conducted in order to fully identify their function in colonic epithelia and CRC cells.
Abstract 114
Mechanisms for Pathway-Selective Insulin Resistance: Implications for Obesity Associated
Coronary Heart Disease
Eileen A. Wang (Rush Medical College), Brian T. Palmisano, John M. Stafford, Vanderbilt University
Obesity and diabetes type 2 greatly increase the risk for coronary heart disease, which is a major
cause of morbidity and mortality in Western society. Insulin resistance is associated with a number of
risk factors including dyslipidemia, elevated serum glucose and insulin levels, and hypertension,
culminating in increased risk of type 2 diabetes and coronary heart disease. The liver is a major
contributor in triglyceride production and glucose metabolism. Hepatic lipid metabolism is regulated
through de novo lipogenesis, fatty acid esterification, and VLDL secretion.
An interesting observation is that with obesity, insulin signaling is impaired for glucose metabolism,
yet seems to be intact with regards to promoting lipid synthesis. In hepatic metabolic disease, hepatic
glucose and lipid metabolism are altered, causing a dysregulation of insulin dependent glucose
metabolism and increased insulin dependent lipid metabolism. This is called pathway selective insulin
resistance. It is not known the mechanisms of that lead to this phenomenon.
We hypothesize that pathway-selective insulin resistance can be induced in mice fed with a high fat
diet through induction of known pathways. C56B1/6 mice that were fed a high fat diet for 8 weeks.
Mice were fasted for 5 hours and hyperinsulinemic-euglycemic clamp was performed with a glucose
and insulin infusion and a saline infusion. It was found that mice fed a high fat diet were insulin
insensitive compared to mice fed a low fat diet. To determine how insulin regulates mRNA targets of
known glucose and lipid metabolic pathways in the setting of hepatic insulin resistance in vivo, mRNA
of liver cells were extracted and reverse transcribed into cDNA. Relative mRNA expression of known
genes in the high fat diet and low fat diet treated with insulin was compared to control saline low fat
diet. We found that insulin treatment in high fat mice was unable to repress Pepck-1 and G6pase
compared to insulin treatment in the low fat diet mice. Additionally, insulin treatment in high fat diet
mice upregulated the expression of Sqs1 and SREBP2, thus inducing the lipogenesis pathway. A
high fat diet induces pathway-selective insulin resistance in mice. Deep sequencing data will reveal
novel gene targets and pathways of pathway-selective insulin resistance. Our proposal is a systems
approach to discovering pathway selective insulin resistance with regards to mRNA target. A better
understanding of insulin regulation with mRNA may yield novel insights into insulin regulation of gene
expression such as novel transcriptional regulators of insulin sensitivity in the pathway that will
suppress hepatic gluconeogenesis and suppress de novo lipogenesis. An understanding of the genes
responsible for pathway selective insulin resistance may result in a more effective treatment for
diabetes type 2 and a reduction in cardiovascular complications.
Abstract 115
The use of family centered programming to improve physical activity for parents
and preschool children
Bianca Marks (Meharry Medical College School of Medicine), David Maynard, William
Heerman MD, Shari Barkin MD, Vanderbilt University Medical Center
Childhood obesity affects 1 in 4 children in the state of Tennessee, with Latino children
being at a disproportionally higher risk. The GROW trial is an NIH funded, large
randomized controlled trial aimed at preventing childhood obesity through family
centered and community focused behavioral intervention programming This project fits
under the umbrella of the GROW trial, and its specific purpose is to assess how
underserved families enrolled in GROW with preschool aged children community
centers and programming. It was hypothesized that the undeserved families will use
community centers and programming in ways that are most convenient. This specific
project was done by conducting ethnographic field work at the two Nashville community
centers that participate in the GROW study. The results from this study suggested that
programs centered on swim and dance were most popular with preschoolers.
Additionally, the peak time of day for preschool attendance was the afternoon.
Furthermore, families utilized programming most when they shared strong social
networks with other families. Another finding of particular importance is that bilingual
classes had higher attendance rates that classes that were solely offered in English.
Overall, the results from this study can inform the approach of the GROW trial as a
whole as well as Nashville Parks and Recreation.
Abstract 116
A mouse model of diabetes-accelerated atherosclerosis exhibits elevated endothelial cell
Vcam1, Icam1 and Ccl2 expression: Possible role for hyperglycemia in combination with
inflammation
Dilreet Rai1, Jenny E. Kanter2 and Karin E. Bornfeldt2
1.University of Missouri-Kansas City School of Medicine, Kansas City, MO, 2. Diabetes and
Obesity Center of Excellence, University of Washington School of Medicine, Seattle, WA
Diabetes results in an increased risk of cardiovascular disease mediated by increased
atherosclerosis. Diabetes accelerates early atherosclerotic lesions, which are primarily
composed of myeloid cells. Preliminary data show that freshly isolated aortic endothelial cells
from a mouse model of diabetes-accelerated atherosclerosis (streptozotocin-induced diabetes
in LDL receptor-deficient mice) express higher levels of adhesion molecules including Vascular
Cell Adhesion Molecule 1 (VCAM-1) and Intercellular Adhesion Molecule 1 (ICAM-1) as well as
the chemokine CCL-2. Whereas the effects of glucose on Human Umbilical Vein Endothelial
cells are known, it is not known if similar changes occur in mouse primary endothelial cells in a
model of diabetes-accelerated atherosclerosis. We hypothesize that diabetes, in part,
accelerates atherosclerosis by augmenting monocyte adhesion to the endothelium and that the
effects on the endothelium is mediated by a combination of elevated glucose and inflammatory
mediators. To test the hypothesis that elevated glucose stimulates increased myeloid cell
adhesion via increased expression of Vcam1, Ccl2 and Icam1, we isolated primary heart
endothelial cells from LDL-receptor deficient mice. Endothelial cells were stimulated in 20 mM
glucose plus 5 mM mannitol (osmotic control) or 5.5 mM glucose plus 19.5 mM mannitol in the
presence or absence of 20 ng/ml TNF-α for 4 hours. RNA from freshly isolated aortic endothelial
cells from steptozotocin-diabetic mice and controls were isolated by flushing the aorta with
Qiazol. RNA was isolated, reverse transcribed, and subjected to real-time PCR. As expected,
TNF-α stimulated the expression of Vcam1 (8.76±0.8-fold), Ccl2 (34.4±11.7-fold) and Icam1
(12.9±1.7-fold) mRNA compared to unstimulated cells under normal glucose conditions: Vcam1
(1.05±.2-fold), Ccl2 (1.01±0.05-fold), Icam1(1.26±0.5-fold). Interestingly, the increase in TNF-astimulated Vcam1 (14.6±4.6-fold over basal; N=6), Ccl2 (135±73.2-fold; N=5) and Icam1
(37.5±15.8-fold; N=5) expression was further elevated if cells were stimulated in the presence of
high (20 mM) glucose. Elevated glucose alone, in the absence of TNF-a, had no effect. Finally,
diabetes resulted in similarly increased expression of Vcam1 (2.74 ± 0.1; N=4), Icam1 (2.4 ±
0.4; N=3) and Ccl2 (1.78 ± 0.6; N=4) in aortic endothelial cells from diabetic mice compared to
non-diabetic mice; Vcam1 (1.19 ± 0.4-fold; N=4), Icam1 (1.12±0.3-fold; N=4) and Ccl2
(1.05±0.2-fold; N=4).
We conclude that diabetes enhances the expression of Vcam1, Icam1 and Ccl2 in the aortic
endothelium, and that these changes are mimicked by exposure of isolated endothelial cells to a
combination of elevated glucose and TNF-a. Our results suggest that the diabetic effects on the
endothelium might be driven by hyperglycemia and an increased inflammatory environment in
diabetes. These proinflammatory changes in the vasculature likely play a role in accelerating
atherosclerosis in diabetes.
Abstract 117
Disruption of Hepatocellular ERBB3 Expression Suppresses Diethylnitrosamine-Induced
Hepatocellular Carcinogenesis
Michael A. Weintraub (Rutgers - Robert Wood Johnson Medical School), Annam Abbasi, Xiuqi
Zhang, Lawrence A. Scheving, William E. Russell, Vanderbilt University Medical Center
The liver has an extraordinary ability to regenerate in response to injury. With chronic injury,
regeneration can eventually become dysregulated, leading to hepatocellular carcinogenesis.
Hepatocellular carcinoma (HCC) is the second leading cause of cancer death with ineffective
treatment options and a five-year survival rate of 12%. Members of the ERBB receptor tyrosine
kinase family are major regulators of liver regeneration and may have a role in HCC. To test the
hypothesis that ERBB3 and EGFR (ERBB1) are important regulators of HCC formation, ERBB3
and EGFR were inactivated in a hepatocellular-specific manner by breeding Cre-recombinase
and ERBB3 or EGFR loxP mice. To initiate tumorigenesis, diethylnitrosamine (DEN) was
injected into wildtype (WT), ERBB3 hepatocyte-specific knockout (HS-KO) and EGFR HS-KO
mouse pups. At 8 months, mouse liver tissue was harvested, tumors were counted and cell
proliferation was assessed. It was determined that ERBB3 HS-KO mice, but not EGFR HS-KO
mice, had a reduction in hepatic tumors (p<0.01) and lower levels of the two proliferation
markers that were evaluated, Ki67 (p=0.05) and cyclin A (p<0.01). ERBB2, normally not
expressed in adult mouse liver, was detected in DEN-injected mice. ERBB3 HS-KO mice
showed reduced ERBB2 expression (p<0.01), suggesting that the induction of ERBB2 may be
partly dependent upon ERBB3. ERBB3 HS-KO resulted in diminished STAT3 activation
(p<0.01), but did not affect activation of other downstream signaling molecules AKT, ERK1, or
ERK2. These observations suggest that ERBB3 may have a role in hepatocellular
carcinogenesis and could become a target in the treatment of HCC.
Abstract 118
TRPM7 is a critical regulator of endocrine pancreatic development and islet cell function.
Thomas J. Galletta (Northeast Ohio Medical University), Prasanna K. Dadi, David A. Jacobson,
Vanderbilt University, Nashville, TN
Transient receptor potential melastatin-like 7 (TRPM7) is the most highly expressed TRP
channel in the human pancreatic islet. TRPM7 serves many important functional roles, such as
modulating Ca2+ influx, apoptotic signaling, neurotransmitter release, and exocrine pancreatic
development. While these roles may influence pancreatic islet function, the influence of TRPM7
in the pancreatic islet has not been determined. Here we assessed whether TRPM7 plays a role
in the growth and development of the endocrine pancreas, islet cell apoptosis, and glucosestimulated insulin secretion (GSIS). Our approach incorporated mouse models with acute beta
cell specific (MIP-cre/ERT-TRPM7fl/fl) and chronic pancreatic specific (Pdx-Cre-TRPM7fl/fl)
TRPM7 ablation. First we measured pancreatic mass and total pancreatic insulin from Pdx-CreTRPM7fl/fl mice; pancreatic mass was reduced by 36% (p < 0.05) and total pancreatic insulin
was reduced by 47% (p < 0.05) compared to control pancreata. We then evaluated islet cell
function by measuring Ca2+ influx and GSIS utilizing islets from both TRPM7 ablation models.
TRPM7 activity is modulated by ATP, and in pancreatic beta cells the ATP/ADP ratio increases
in response to glucose. Thus, we measured glucose-stimulated beta cell Ca2+ influx and found
that it was reduced by 27% (p < 0.001) with ablation of TRPM7. Interestingly, however, islets
isolated from both Pdx-Cre-TRPM7fl/fl and MIP-cre/ERT-TRPM7fl/fl mice demonstrated increased
GSIS with a 40% increase in Pdx-Cre-TRPM7fl/fl islets (p < 0.01) and a 47% increase in MIPcre/ERT-TRPM7fl/fl islets (p < 0.01). Therefore, TRPM7 may regulate the exocytosis of insulin
granules independent of Ca2+ influx. Finally, we measured TRPM7’s effect on islet cell apoptosis
because apoptotic signaling has been shown to activate TRPM7 channels. We found that when
islet apoptosis was induced via pro-inflammatory cytokine stimulation, glucose-stimulated Ca2+
influx was reduced by 58% in beta cells with acute ablation of TRPM7 (p < 0.001). Additionally,
islets with acute beta cell and chronic pancreatic TRPM7 ablation were more sensitive to
cytokine-induced apoptosis compared with controls; there was a 25% increase in apoptosis for
islets without beta cell TRPM7 (p < 0.01) and a 22% increase in apoptosis for islets without
TRPM7 (p < 0.05). Our results indicate that TRPM7 is a critical regulator of endocrine
pancreatic development and physiological islet cell function. Furthermore, these results identify
an important role for TRPM7 in limiting beta cell destruction during inflammatory conditions
associated with diabetic islets. Thus, TRPM7 is a potential therapeutic target for increasing
GSIS and reducing beta cell destruction during the pathogenesis of diabetes.
Abstract 119
Resting State fMRI and PET Correlations in the Dopamine Reward Pathway in Obese
Adults with Type 2 Diabetes Mellitus
Le Zhong, B.S. (University of Miami Miller School of Medicine); Waqas Majeed, Ph.D. (Lahore
University of Management Sciences); Heidi Silver, Ph.D., R.D. (Vanderbilt University Medical
Center); Kevin Niswender, M.D., Ph.D. (Department of Medicine, Vanderbilt University Medical
Center); Malcolm J. Avison, Ph.D. (Vanderbilt University Institute of Imaging Science)
The dopamine (DA) reward pathway, whose dysfunction is a hallmark of drug addiction, has
been hypothesized to exhibit similar alterations in obesity. A recent model of the DA reward
pathway suggests that the nucleus accumbens (NAcc) integrates inputs from salience
attribution areas including the amygdala, which drive motivated drug and food seeking
behaviors, and frontal lobe areas such as medial orbitofrontal cortex (MOFC) that exert
cognitive control over this motivational drive. Thus signals from the amygdala have been
hypothesized to upregulate the reward pathway, while signals from MOFC have been
hypothesized to suppress the cue-driven reward seeking. Using resting state functional
magnetic resonance imaging (rsfMRI) and 18F-Fallypride positron emission tomography (PET)
data combined with fat-water imaging, biochemical, and demographic data obtained from the 2nd
and 6th weeks of a longitudinal study of the impact of insulin therapy on brain DA systems, we
examined the impact of adiposity, insulin resistance, NAcc DA D2 receptor availability, and
leptin on the relative strengths of the NAcc-Amygdala and NAcc-MOFC connections determined
from the strength of the inter-regional temporal correlation (r2) of the resting state fMRI time
course. We show that in obese adults with moderate type 2 diabetes mellitus, the ratio of
visceral adipose tissue to lean tissue, a direct measure of adiposity, correlated negatively with
the non-displaceable binding potential obtained from PET in several brain regions. Treatment
with amphetamine (AMPH) led to a significant negative NAcc-MOFC r2 relationship with the total
adipose tissue to lean tissue ratio (TAT/LT), but no significant change in the dependence of the
NAcc-Amygdala r2 on TAT/LT. Treatment with insulin detemir led to decreased dependence of
the NAcc-MOFC r2 and increased dependence of the NAcc-Amygdala r2 on TAT/LT. AMPH
administration alone did not significantly change the NAcc-Amygdala r2, while it increased the
NAcc-MOFC r2. There were significant correlations between fasting leptin levels, an indirect
measure of adiposity, and the NAcc-Amygdala r2 but not the NAcc-MOFC r2. The NAccAmygdala r2 correlation with leptin levels was unaffected by AMPH, but the direction of the
correlation was affected by insulin detemir treatment, suggesting an alternate mechanism
through which leptin may mediate NAcc-Amygdala connections with modulation from insulin.
Our studies provide evidence that adiposity and its correlates play both direct and indirect roles
in modulating the DA reward pathway and affecting adjacent cortical regions that govern it.
Abstract 120
Regulation of Iron Homeostasis in Macrophages in Response to Helicobacter pylori
Infection
Cassie Xu (Indiana University School of Medicine), Jennifer Noto, Richard Peek, Vanderbilt
University Medical Center
Progression to gastric adenocarcinoma from Helicobacter pylori infection, the strongest
known risk factor in the development of gastric cancer, is dependent on an interplay between
host and pathogen factors. The development of gastric adenocarcinomas induced by H. pylori
infection has been observed to be accelerated by iron deficiency; however, the effects on iron
levels in infected individuals by H. pylori are largely unknown. As the expression of hepcidin,
the major regulator of iron homeostasis which inhibits the release of iron from duodenal
enterocytes and macrophages by binding and leading to the degradation of the only known iron
exporter, ferroportin, is known to be enhanced by inflammation and infection, we predict that H.
pylori infection of macrophages, which play a large role in iron recycling and exhibit strong
expression of ferroportin, will lead to an increase of hepcidin expression and a decrease in
ferroportin expression. In order to address our prediction, hepcidin and ferroportin expression
was assessed in RAW cells, murine macrophages, infected with oncogenic H. pylori cag+ strain
7.13 and its cagA- and cagE- mutants using quantitative real-time PCR. Similarly, hepcidin and
ferroportin expression were measured in THP-1 cells, a human monocyte line, that were
infected with H. pylori strain 7.13 and concurrently secreted hepcidin protein levels by the
infected THP-1 cells were measured using an ELISA assay. In the RAW cells, a moderate
increase of hepcidin expression was observed in a cagA- and cagE- independent manner, while
ferroportin expression was observed to be decreased in a cagA- and cagE- independent manner.
Similar trends in hepcidin and ferroportin expression were observed in the human THP-1 cells,
but with a greater induction of hepcidin expression levels. Secreted hepcidin protein levels by
infected THP-1 cells were also found to be elevated. This data suggests that hepcidin
expression in macrophages is increased upon infection with H. pylori, while ferroportin
expression is decreased, demonstrating that H. pylori might have an effect on host iron
homeostasis by limiting circulating iron; however, more studies must be done to prove stronger
statistical significance.
Abstract 121
Technology-Mediated Lifestyle Interventions for Reducing Risk for Type 2 Diabetes: a
Systematic Review
Rachel Bian (University of Michigan Medical School); Neal Kaufman, MD; Ananda Sen, PhD;
Caroline Richardson, MD, University of Michigan
Context: Weight loss through lifestyle interventions, such as those delivered through the
Diabetes Prevention Program, has been shown to reduce risk for developing type 2 diabetes.
Technology-mediation of these interventions can help overcome barriers to program delivery
and can be used to disseminate diabetes prevention programs on a larger scale.
Methods: In this systematic review, 6 databases were searched to identify studies reporting
weight loss that used technology to carry out diet and exercise interventions targeting those at
high risk for diabetes. Controlled trials and prospective cohort studies published after January 1,
2002 were included.
Results: The search identified 431 citations, and out of those ten studies met inclusion criteria,
evaluating a total of 14 technology-mediated intervention arms. Average weight loss ranged
from 0.1kg to 6.7kg across the intervention arms. Effects of intervention on diabetes incidence
and decreased A1c levels were also noted, and results of technology-mediated interventions
were compared to that of standard care and in-person intervention controls.
Conclusion: Technology-mediated diabetes prevention programs can result in clinically
significant amounts of weight loss and cause significant decreases in prediabetes prevalence
and diabetes incidence.
Abstract 122
Role of Discoidin Domain Receptor 1 (DDR1) in Mesangial Cells
Vivian Joan Ortiz Baez (San Juan Bautista School of Medicine, Caguas PR.), Ambra Pozzi, and
Corina Borza. Department of Medicine, Division of Nephrology, Medical Center North,
Vanderbilt University, Nashville, TN.
Discoidin Domain Receptor 1 (DDR1) is an extracellular matrix and tyrosine kinase receptor that
binds to and is activated by collagen. Up-regulation of this receptor has been observed in many
fibrotic diseases, including kidney diseases. However, whether up-regulation of this receptor
contributes to or counteracts the disease process in unclear. Based on the finding that
collagen-mediated activation of DDR1 leads to increased collagen synthesis, and collagen is a
key matrix deposited in the course of fibrosis, we hypothesize that activation of DDR1 plays a
deleterious effect in kidney fibrosis. Our study was aimed to identify the potential pro-fibrotic
pathways activated by DDR1. To do this, we utilized kidney cells either lacking or expressing
DDR1 and analyze the activation of three major mediators of fibrosis, namely ß-catenin, STAT3
and c-Jun, upon collagen stimulation. Upon collagen stimulation no differences in total ß-catenin
and c-Jun were observed between untreated and collagen treated cells. Interestingly the
phosphorylation of STAT3 on Y705 was decreased in cells expressing DDR1 stimulated with
collagen compared to collagen-stimulated DDR1-null cells. Although the well-accepted function
of activated (e.g., phosphorylated) STAT3 is to translocate the nucleus and activate pro-fibrotic
signaling, cytokine mediated-STAT3 phosphorylation has been recently shown to protect certain
organs against damage and fibrosis. Thus, it is conceivable that DDR1 might promote collagen
synthesis by decreasing the activation of STAT3. More studies are needed to determine
whether indeed decreased STAT3 phosphorylation in DDR1 expressing cells stimulated with
collagen is required to drive DDR1-mediated production of collagen.
Abstract 123
Effects of a clinically relevant dose of immunosuppressant drug, Tacrolimus, on human
islet function and survival in vivo
Kelsey Eitel (Loyola University Chicago Stritch School of Medicine), Scott Wisniewski, Ana
Padgett, Chunhua Dai, Alvin C. Powers, Vanderbilt University
Patients undergoing organ transplantation are at an increased risk of developing diabetes
mellitus post-transplantation. This is thought to be due to the diabetogenic effects of
immunosuppressive drugs, but the mechanism of this effect is poorly understood. To test
whether a clinically relevant dose of the immunosuppressive drug Tacrolimus (TAC) impairs
human islet function and survival in vivo, we transplanted 1,500 islet equivalents (IEQ) beneath
the kidney capsule of immunodeficient, normoglycemic NOD-scid IL2r-γ-null (NSG)-DTR mice
and treated them with Diphtheria toxin (DT) to ablate mouse beta cells. Two weeks later the
normoglycemic mice were treated with 0.25 mg/kg/day of TAC or saline via a subcutaneous
osmotic pump for four weeks. The TAC dose needed to obtain a clinically relevant level was
determined by measuring the TAC level in blood. During an intra-peritoneal glucose tolerance
test, TAC-treated mice had a slightly elevated fasting blood glucose (TAC 158 mg/dl, n = 3 vs.
control 87 mg/dl, n = 3, p = 0.0373) and had impaired glucose clearance with the most
significant blood glucose elevation seen at 15 minutes post-IP glucose injection (TAC 392 mg/dl,
n = 3 vs. control 182 mg/dl, n = 3, p = 0.0242). TAC treatment did not change human basal
insulin levels but did impair glucose/arginine-stimulated human insulin secretion. Human islet
grafts in TAC-treated mice and control mice had similar levels of beta cell apoptosis (n =
3/group, p = 0.4226), beta cell proliferation (n = 3/group, p = 0.4514), and beta (n = 3/group, p =
0.0804), alpha (n = 3/group, p = 0.0564), and delta (n = 3/group, p = 0.3343) cell ratios. These
results suggest that a clinically relevant dose of TAC impairs human beta cell function, but does
not affect beta cell survival, proliferation, or mass.
Abstract 124
Designing Targeted Fracture Therapies for Diabetic Patients
Sagar S. Deshpande (University of Michigan), Noah S. Nelson, Yekaterina Polyatskaya,
Ernestina Schipani, Karl J. Jepsen, Steven A. Goldstein, Steven R. Buchman, University of
Michigan.
It is clinically well established that diabetic bone fractures heal poorly, often taking twice as long
as non-diabetic fractures to achieve consolidation. Despite this fact, there are no current
therapies targeted at accelerating bone healing in this specific population. Our laboratory has
previously utilized Deferoxamine, an FDA-approved iron chelator, as an osteogenic and
angiogenic agent in the setting of irradiated fracture healing. Moreover, Deferoxamine has
demonstrated utility in healing diabetic pressure ulcers and other soft-tissue deficits. As such, it
our hypothesis that administration of Deferoxamine will create bony unions in a diabetic, criticalsized femoral fracture in a rat model. Currently, this study is in pilot phase, wherein we are
evaluating the ideal temporal endpoint for this study. Once we have done so, we plan to move
forward to the main arm of the study, in order to assay the efficacy of Deferoxamine in our
model.
Abstract 125
Evaluating Methods to Enhance Tufts D2d Study Recruitment
Pamela Sherwood (Tufts University School of Medicine), Sarah Gunn, MS, Anastassios Pittas,
MD, Tufts Medical Center
D2d is a multi-center clinical trial to test whether vitamin D supplementation reduces diabetes
risk in people at high-risk (pre-diabetes). A major recruiting challenge for D2d is that 9 out of 10
people with pre-diabetes are unaware of their risk. This study addresses two major aims: (1) to
assess the highest yield methods of recruitment for the study at the present time and (2) to
evaluate the attitudes of current participants toward the use of social networking for clinical trial
recruitment. To test the hypothesis that referrals from primary-care physicians were the highest
yield method of recruitment, first, a chi square test was performed to assess whether there was
a significant difference in the method of recruitment for participants who made it to
randomization as opposed to those who did not qualify for randomization into D2d. Next,
pairwise comparisons of the main D2d recruitment methods were performed. There was a
significant difference (p=0.025) in recruitment methods for those who made it to randomization
as compared to those who did not make it to randomization. It was shown by pairwise
comparison that referral was the highest yield recruitment method as compared to
advertisements (p=0.005), database (p= 0.038), and other (p=0.014). To test the hypothesis
that Tufts D2d study participants are active on social networking sites and would be interested
in using social networking to learn about clinical trials for which they are eligible, surveys were
created and distributed to participants by mail and email. Survey results were analyzed using
basic statistics. 60% of survey respondents used social networking and 40% said that they
would use or join a social networking site to receive information about the D2d study or other
clinical trials. 100% of those who would use a social networking site to site to receive
information about the D2d responded that their preferred platform would be Facebook. The
results support the conclusion that referrals from primary-care physicians are the highest yield
method for recruiting pre-diabetic participants to D2d. More data is needed to fully analyze the
results of the social networking survey so no valuable conclusions can yet be made from the
data available.
Abstract 126