Download Pancreatic Structure and Function Evaluation in Type 2 Diabetic Rat

Pancreatic Structure and Function
Evaluation in the Type 2 Diabetic Rat Model
It is estimated that 347 million people worldwide are affected by diabetes.
Diabetes mellitus type 2 is a metabolic disorder that is characterized by high
blood glucose in the context of insulin resistance and insulin deficiency in
humans. Type 2 diabetes comprises 90% of people with diabetes around the
world and is primarily caused by obesity and physical inactivity.
Endpoints
• Body weight
• Food consumption
• Water consumption
Following the market of several GLP-1 agonists for the treatment of type 2
diabetes, an association between the use of these therapies and an increased
incidence of pancreatitis was suggested based on case reports. This suggested
association led to the request from the US Food and Drug Administration to all
developers of incretin-based therapies to conduct a 3-month preclinical toxicity
study that would investigate the potential effects of their candidate drugs on
pancreatic structure and function in an insulin-resistant model of type 2 diabetes.
Consequently, the Charles River preclinical diabetes portfolio has expanded
over recent years to include fully GLP-compliant investigative study of pancreatic
exocrine biomarkers, histology, immunohistochemistry and histomorphometry in
the Zucker diabetic fatty (ZDF) male rat model.
These preclinical studies allow the assessment of potential toxicity of a given
compound on the pancreatic structure and function through the serial monitoring
of pancreatic and diabetic markers with extensive histopathologic evaluation of
the pancreas, including immunohistochemistry and morphometric assessment of
cell proliferation and apoptosis of ductal epithelium in the insulin-resistant Zucker
diabetic fatty (ZDF) rat model.
Typical toxicology safety endpoints such as body weight, food consumption,
water consumption, clinical signs, ophthalmology, bioanalysis, immunogenicity,
behavioral assessments, clinical pathology examination and gross and
microscopic examinations can be included. Board-certified ophthalmologists,
clinical pathologists and anatomical and experienced toxicologists are available
to interpret the data generated and produce high-quality contributing reports.
The male ZDF rat model has proven to be an appropriate model, as the male
ZDF rat progresses through several stages of diabetes in a relatively predictable
age-dependent fashion when maintained under the appropriate conditions
(standard laboratory diet such as PMI Certified Rodent Chow 5008). The ZDF
male rat typically starts to develop hyperglycemia and hyperlipidemia by 8 weeks
of age and type 2 diabetes by 12 weeks of age.
• Clinical signs
• Opthalmology
• Bioanalysis
• Immunogenicity
• Clinical pathology assessment
• Gross and microscopic examinations
Services
• Laboratory Services
- Method development
- Validation for dose formulation analysis
- Bioanalysis
- Immunogenicity (HPLC, LC/MS/MS, ELISA, qPCR)
• Monitoring of Diabetic State and
Pancreatic Toxicity
• Study Termination and Analysis
• Pathology Evaluation
• Immunohistochemistry
• Histomorphometry
• Photographic Documentation
[email protected]
www.criver.com
© 2013, Charles River Laboratories International, Inc.
Sample Study Design
6 Weeks:
Animals received,
acclimation period
8 Weeks:
Dosing initiated
via appropriate
route; animals
become
hyperglycemic/
hyperlipidemic
12 Weeks:
Type 2 diabetes
developed in
animals
Optimized housing conditions, veterinary oversight and
modified handling procedures adapted to their different physical
proportions (short limbs and increased fat deposits) are used
as a standard to optimize conditions for the animals’ health and
longevity during these more fragile months of their lifespan.
Laboratory Services
Charles River offers a complete range of laboratory support services
and can provide method development and validation for dose
formulation analysis, as well as bioanalysis and immunogenicity
using standard methods such as HPLC, LC/MS/MS, ELISA or
specialized methods of analysis (e.g., qPCR).
Monitoring of Diabetic State and Pancreatic
Toxicity
A range of already-validated markers are available for monitoring
the animals’ diabetic state (including, but not limited to, insulin,
glucose, glycated hemoglobin) and pancreatic toxicity (including,
but not limited to, total amylase, pancreatic amylase, lipase, urea
and creatinine) throughout the study.
8-20 Weeks:
Serial monitoring
of disease model
and pancreatic
markers
21 Weeks:
Study termination
and analysis:
necropsy,
pathology
evaluation, IHC,
histomorphometry
Pathology Evaluation
Pathologists evaluate the pancreatic tissue with H&E-stained
step and serial sections for immunohistochemistry and/or
cytochemistry of head, body and tail regions. Transmission
electron microscopy (TEM) is available, which may be of interest to
further assess potential subcellular alterations. The Provantis 8™
computer system, which allows for rapid tabulation of data sets, is
used for reporting pathology findings.
Immunohistochemsitry
A range of validated immunohistochemical staining procedures
are available, including KI-67 for cell proliferation marker,
Cytokeratin for duct epithelial cell marker and TUNEL staining for
apoptosis.
Histomorphometry
Study Termination and Analysis
Quantitative histological assessment utilizing Image-Pro® Plus
is available from our image analysis units. These facilities
are available for various applications, such as cell counting,
planimetric measurements from tissue structures and measuring
areas, and quantitation of KI-67/Cytokeratin-19- and TUNEL/
Cytokeratin-19-positive cells in the pancreas of ZDF male rats.
Necropsy
Photographic Documentation
Pathologists oversee all steps of the work from necropsy to slide
preparation. In addition to the weighing and comprehensive
collection of tissues and description of lesions at necropsy, whole
blood perfusion can be conducted using various fixatives. Beyond
the routine histology services, specialized pancreatic trimming,
embedding and sectioning can be performed on perfused or
immersed-fixed tissue, as well as cryostat sectioning of frozen
pancreas. The application of specialized immunohistochemical
and cytochemical staining, in combination with morphometric
evaluation, can also be utilized in addition to the standard
morphologic evaluation of hematoxylin and eosin (H&E) stains.
A digital imaging unit (GLP-compliant) for the capture and
printing of high-quality digitized images of gross and microscopic
pathology specimens is also available. The Aperio® ePathology
Solutions™ system for digitizing pathology facilitates image
sharing, consultation, collaboration and discussion, and the high
quality of the digital images enables their use in study reports and
scientific publications.
[email protected]
www.criver.com
© 2013, Charles River Laboratories International, Inc.