Download Impaired left ventricular relaxation in type 2 diabetic rats is related to

The European Journal of Heart Failure 8 (2006) 2 – 6
www.elsevier.com/locate/heafai
Impaired left ventricular relaxation in type 2 diabetic rats is related to
myocardial accumulation of N q-(carboxymethyl)lysine
Stefan Schäfer*, Jochen Huber, Cornelia Wihler, Hartmut Rütten,
Andreas E. Busch, Wolfgang Linz
Therapeutic Department Cardiovascular Diseases, Aventis Pharma Deutschland GmbH, Building H 821, D-65926, Frankfurt am Main, Germany
Received 2 February 2005; accepted 27 April 2005
Available online 8 August 2005
Abstract
Myocardial dysfunction in the absence of myocardial ischemia is frequent in patients with diabetes mellitus but the underlying
pathomechanism is unclear. We investigated whether accumulation of advanced glycation end products (AGEs) in the diabetic myocardium is
related to its functional abnormalities.
In 11 male homozygous Zucker diabetic fatty rats (ZDF/Gmi-fa/fa) aged 37 weeks (OBESE) and 11 non-obese, non-diabetic littermates
(LEAN), we measured left ventricular function (pressure – volume catheter) and levels of N q-(carboxymethyl)lysine (CML), a prototypical
AGE, in serum and the left ventricle (competitive enzyme linked immuno-assay).
Overt diabetes mellitus (HbA1c > 9%) was present in all OBESE animals but not in LEAN. Systolic left ventricular function was not
different between the groups, but the markers of left ventricular relaxation, dP / dt min and the relaxation constant s, were impaired in OBESE.
In parallel, CML levels were increased in serum (273 T 15 vs. 197 T 10 ng/ml, p < 0.05) and in the left ventricle (18.4 T 1.1 vs. 12.5 T 2.0 ng/mg
protein, p < 0.05) in OBESE compared to LEAN. There was a linear correlation between s and the left ventricular CML levels (r = 0.65;
p < 0.05).
We conclude that type 2 diabetes is associated with predominant left ventricular diastolic dysfunction. Myocardial accumulation of
advanced glycation end products may contribute to relaxation abnormalities in type 2 diabetes.
D 2005 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
Keywords: Zucker diabetic fatty rat; Diabetic cardiomyopathy; Advanced glycation end products
1. Introduction
Diabetes mellitus is a risk factor for heart failure.
Although a large proportion of the excess risk of heart
failure in diabetic individuals can be attributed to coronary
artery disease and its myocardial complications, several
studies have indicated the existence of a nonischaemic,
specific ‘‘diabetic cardiomyopathy’’. A recent survey in the
US has revealed an independent association between
diabetes and nonischaemic cardiomyopathy [1]. Based on
the perturbations of glucose and lipid metabolism occurring
* Corresponding author. Tel.: +49 69 30513391; fax: +49 69 30516394.
E-mail address: [email protected] (S. Schäfer).
in diabetes, a number of functional and morphological
changes have been identified within the myocardium which
may lead to heart failure in diabetic patients in the absence
of coronary artery disease [2]. Chronic hyperglycaemia
promotes the glycation of proteins, which may directly
impair function and structure of the myocardium. In
addition, the formation of advanced glycation end products
(AGEs) can modulate myocardial function via activation of
specific receptors (eg., RAGE) [3]. N q-(carboxymethyl)lysine (CML) is a prototypical AGE, which is derived from
oxidative modification of glycated proteins. Serum levels of
CML and other AGEs are increased in patients with type 2
diabetes [4], and accumulation of CML has been reported in
the myocardium from diabetic patients [5]. In type 1
diabetic patients, serum levels of AGEs have been
1388-9842/$ - see front matter D 2005 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
doi:10.1016/j.ejheart.2005.04.011
S. Schäfer et al. / The European Journal of Heart Failure 8 (2006) 2 – 6
correlated to left ventricular (LV) diastolic dysfunction [6].
In rats with streptozotocin-induced, type 1 like diabetes,
myocardial compliance was linked to myocardial collagen
AGEs [7]. Aminoguanidine, an inhibitor of AGE formation,
prevented both myocardial AGE fluorescence and LV
stiffness in this model [7].
Interestingly, the role of AGEs for myocardial function in
type 2 diabetes has received little attention despite the
obvious differences between the two types of diabetes.
Hyperinsulinaemia, obesity, and hyperlipidaemia may modulate the metabolism of AGEs and myocardial function
independently. In the present study, we therefore investigated whether there is a link between myocardial function
and AGE accumulation in type 2 diabetes.
2. Methods
The animal experiments were performed in accordance
with current Sanofi-Aventis Laboratory Animal Science and
Welfare guidelines and the German law for the protection of
animals.
2.1. Animals
Eleven male Zucker diabetic fatty rats (ZDF/Gmi-fa/fa)
and eleven heterozygous (ZDF/Gmi-+/fa) lean littermates
were purchased from Charles River Germany GmbH
(Sulzfeld, Germany) and kept in our local facilities in
Frankfurt-Hoechst. The animals were housed individually in
standard cages and received a standard chow diet (standard
diet #1320, Altromin, Lage, Germany) and tap water ad
libitum. Metabolic characterization was performed at age
10, 17, 27, and 37 weeks in haemolysate which was taken
from the retro-orbital plexus under light anesthesia (3.5
vol.% isoflurane in 34/66 N2O/O2). Glycated haemoglobin
(HbA1c) was measured in these samples using a standard kit
(Cobas Integra, Roche diagnostics, Mannheim, Germany).
2.2. In vivo experiments
At age 37 weeks, the animals were anaesthetized with
thiopental (Narcoren, 100 mg kg 1 i.p., Merial, Hallbergmoos, Germany), intubated and artificially ventilated. For
the assessment of pressure – volume relationships, the left
3
ventricle was catheterized retrogradely via the right carotid
artery using a 1.4 F impedance-micromanometer catheter
(Millar Instruments, Houston, Texas, USA). In brief, the
method is based on measuring the time-varying electrical
conductance signal of two segments of blood in the left
ventricle, from which total volume is calculated. Raw
conductance volumes were corrected for parallel conductance by the hypertonic saline dilution method. For absolute
volume measurements, the catheter was calibrated with
known volumes of heparin treated rat blood. Pressure –
volume signals were recorded at steady-state and during
transient preload reduction achieved by vena cava occlusion. Data were digitized with a sampling rate of 1000 Hz
and recorded on a PC using specialized software (HEM,
Notocord, Croissy, France). For subsequent analysis of
pressure – volume loops, preload recruitable stroke work
(PRSW), end-systolic pressure volume relationship (Ees),
and end-diastolic pressure volume relationship (EDPVR),
PVAN software (Millar Instruments, INC, Houston, Texas)
was used. Specifically, LV systolic pressure (LVSP), LV
dP / dt max, ejection fraction, cardiac output, the end systolic
myocardial elastance constant Ees, and preload recruitable
stoke work (PRSW) were determined as measurements of
systolic LV performance. LV end diastolic pressure
(LVEDP), LV end diastolic volume (LVEDV), and the slope
of the end-diastolic pressure volume relationship (EDPVR)
were determined as parameters primarily reflecting LV
compliance. As measures of LV relaxation, LVdP/dtmin and
the time constant of LV pressure decay (s, calculated
according to Weisfeldt et al. [8]) were determined.
After completion of haemodynamic measurements, the
animals were sacrificed by quick excision of the hearts
under continuing deep anaesthesia.
2.3. Measurement of CML
CML was determined in serum and heart homogenates
with a competitive enzyme-linked immunosorbent assay
(ELISA) using a CML monoclonal antibody as described
previously [9]. Heart samples were immediately frozen in
liquid nitrogen and ground for 5 min in liquid nitrogen using
a Freezer mill 6750 (C3 Analysetechnik GmbH, Haar,
Germany). From the frozen organ powder, 10 mg were
dissolved in 1 ml PBS buffer pH 7.4 containing 0.5 g/l
Tween-20, 0.5 mM phenylmethanesulfonyl fluoride (Sigma-
Table 1
Biometric and carboxy-methyl-lysine (CML) data
LEAN
OBESE
Age
22 weeks
37 weeks
22 weeks
37 weeks
Body weight
(g)
Heart weight
(g)
Heart / body weight ratio
Serum CML content
(ng/ml)
Heart CML content
(ng/mg protein)
404 T 24
462 T 17
396 T 11
373 T 14*
0.80 T 0.02
0.91 T 0.03
0.89 T 0.04
0.73 T 0.01*
0.20 T 0.01
0.20 T 0.01
0.22 T 0.01
0.20 T 0.01
249.7 T 12.8
197.4 T 9.6
279.4 T 20.2
273.3 T 14.7*
15.9 T 1.3
12.5 T 2.0
23.8 T 1.0*
18.4 T 1.1*
N = 8 – 10, except for CML data at age 22 weeks (where n = 4). Data are mean T SEM. *p < 0.05 vs. respective LEAN.
4
S. Schäfer et al. / The European Journal of Heart Failure 8 (2006) 2 – 6
22
Table 3
Diastolic left ventricular haemodynamic parameters at age 37 weeks
20
τ, ms
18
16
LEAN
OBESE
14
LVEDP
(mmHg)
LVEDV
(Al)
EDPVR
(mmHg/ml)
5.1 T 0.6
4.8 T 0.4
312 T 61
317 T 36
22 T 5
16 T 2
LV dP / dt min
(mmHg/s)
5932 T 504
4383 T 390*
s
(ms)
13.8 T 0.7
17.1 T 0.6*
N = 8 – 10. Data are mean T SEM. *p < 0.05 vs. LEAN. LVEDV, LV end
diastolic volume; EDPVR, slope of the (linear) end diastolic pressure –
volume relationship; s, constant of LV pressure decay.
12
10
10
15
20
25
30
(OBESE) animals weighed less than their non-diabetic
(LEAN) littermates. The lesser body weight in the homozygous compared to heterozygous Zucker diabetic fatty rats
at an older age is a common finding, which is probably due
to an excessive loss of calories (glucosuria, proteinuria),
which cannot be compensated for by an increased food
intake. Absolute heart weight was also less in OBESE
compared to LEAN, but heart-to-body weight ratios were
identical in both groups (Table 1).
Blood HbA1c was 6.1 T 0.2%, 10.0 T 0.4%, 8.7 T 0.4%,
and 10.1 T 0.3% in OBESE at age 10, 17, 27, and 37 weeks
respectively, indicating long lasting diabetes mellitus. In
LEAN, by contrast, HbA1c remained below 5 percent at all
time points.
Myocardial CML, ng/mg protein
Fig. 1. Scatterplot illustrating the significant linear relationship between
myocardial CML levels and the LV relaxation constant s in LEAN and
OBESE rats (r = 0.65, p < 0.05). CML, N q-(carboxymethyl)lysine.
Aldrich Chemie GmbH, Steinheim, Germany) and 1 Ag/Al
aprotinin (Roche Diagnostics, Mannheim, Germany). Samples were vortexed and sonicated (Sonoplus HD 2070,
Bandolin, Berlin, Germany) twice for five seconds to
disintegrate cells. Cell debris was removed by centrifugation. The heart lysates were adjusted to a concentration of 1
mg/ml total protein and 50 Al lysate was used for the CMLELISA. Serum samples were digested with 2 mg/ml
proteinase K (Roche Diagnostics) for 3 h at 37 -C to
liberate CML epitopes. To stop the reaction, 4 mM
phenylmethanesulfonyl fluoride was added and the mixture
was incubated for 30 min at 37 -C. Digested serum samples
were measured in triplicate (50 Al each).
CML contents in serum and plasma were also determined
in a subset of n = 4 animals per group, which were sacrificed
for an interim analysis at age 22 weeks.
3.2. CML
At the interim analysis at age 22 weeks, there were no
differences in serum CML between the two groups, but
myocardial CML content was higher in OBESE (Table 1).
At the final analysis (age 37 weeks), both serum and
myocardial CML contents were higher in OBESE compared
to LEAN (Table 1).
There was a linear correlation between myocardial CML
content and the relaxation parameters s (cf. Fig. 1) and dP /
dt min (r = 0.43, p < 0.05), but not between serum CML
content and s or dP / dt min (each p > 0.1). Also, there were
no significant correlations between CML and the indices of
systolic or myocardial compliance function (data not
shown).
2.4. Statistics
Data are given as mean T SEM. Differences were tested
for significance using unpaired two-sided t-tests. A p value
of less than five percent was considered significant.
3. Results
3.3. Haemodynamics
3.1. Biometric and metabolic data
Haemodynamic parameters at age 37 weeks are summarized in Tables 2 and 3. In OBESE, heart rate was lower
than in LEAN. Indices of the LV systolic function were not
different between the two groups, including LV dP / dt max,
and the load independent indices, Ees and PRSW. In
The biometric data are summarized in Table 1. At the
interim analysis (age 22 weeks), there were no differences
between groups regarding body weight, heart weight, or
heart-to-body weight ratio. At age 37 weeks, the diabetic
Table 2
General and systolic left ventricular haemodynamic parameters at age 37 weeks
LEAN
OBESE
Heart rate
(Beats per minute)
LVSP
(mmHg)
LV dP / dt max
(mmHg/s)
Ejection fraction
(Percent)
Cardiac output
(Al/min/g)
Ees
(mmHg/Al)
PRSW
(mmHg)
294 T 11
232 T 14*
111 T 6
103 T 8
6037 T 485
5123 T 454
54 T 3
51 T 5
116.0 T 19.0
100.3 T 14.6
0.73 T 0.17
0.69 T 0.18
84.7 T 10.0
83.2 T 17.7
N = 8 – 10. Data are mean T SEM. *p < 0.05 vs. LEAN. Ees, end systolic elastance; PRSW, slope of the (linear) preload recruitable stroke work relationship.
S. Schäfer et al. / The European Journal of Heart Failure 8 (2006) 2 – 6
contrast, among the indices of diastolic function, those
reflecting LV relaxation (i.e., dP / dt min and s) were
significantly impaired in OBESE compared to LEAN.
Interestingly, indices of LV compliance (LVEDP, LVEDV,
and EDPVR) were not significantly different between the
two groups.
4. Discussion
The present study demonstrates a predominantly diastolic
LV dysfunction in rats with type 2 diabetes mellitus. More
specifically, we have shown that myocardial relaxation is
prolonged when LV contractility and compliance are not
(yet) significantly impaired in diabetic rats at age 37 weeks.
The functional impairment is related to the myocardial
accumulation of CML, a prototypical advanced glycation
end product (AGE). Taken together, these data support the
hypothesis that AGEs can impair myocardial function and
potentially contribute to heart failure in type 2 diabetes even
in the absence of myocardial ischemia.
Based on early observations of structural alterations in
postmortem diabetic hearts, a number of clinical and
experimental studies have aimed to characterize the function
of the diabetic heart. Systolic or diastolic dysfunction, or
both, has been described inconsistently in patients with type
1 and type 2 diabetes mellitus, using non-invasive — mostly
echocardiographic — methods [10,11], for review see Ref.
[12]. Likewise, echocardiographic studies in experimental
type 2 diabetes have revealed discrepant results. Earlier
reports describing reduced myocardial systolic function in
Zucker diabetic fatty [13] and Goto-Kakizaki rats [14] could
not be reproduced by another group [15]. In addition, Ren et
al. reported decreased contractility and relaxation properties
in cardiomyocytes isolated from obese but non-diabetic
Zucker rats [16]. The present study is the first to use
pressure – volume data in an effort to measure load independent indices of LV systolic and diastolic function. Using
this method, we were able to identify that prolongation of
myocardial relaxation (as distinct from decreased myocardial
compliance) seems to be the predominant feature of diabetic
cardiomyopathy when systolic function is preserved.
Few randomized clinical trials have addressed the effect
of pharmacological treatments in diastolic heart failure, but
interventions leading to bradycardia and angiotensin receptor blockade seem to be effective. Smaller studies indicate
that glycemic control can also improve LV diastolic
dysfunction in type 2 diabetes, but these findings have not
always been reproducible (for review see Ref. [12]). The
specific alterations in myocardial metabolism known to
occur in diabetes may offer additional therapeutic targets for
diabetic cardiomyopathy beyond normalizing blood glucose
levels. Data from diabetic patients have demonstrated an
accumulation of AGEs in different tissues, including the
myocardium [17]. Moreover, serum AGE levels have been
linked to LV diastolic dysfunction in type 1 diabetic patients
5
[6]. Together with the present study in type 2 diabetes, these
data provide a strong rationale for a pathogenetic role of
AGEs in diabetic cardiomyopathy. Of note, LV relaxation
was linked to myocardial, but not serum, CML levels in the
present study. Serum AGE levels are strongly dependent on
liver and kidney function, indicating a major role of the two
organs in metabolism and/or excretion of AGEs [18,19].
Also, a diet rich in AGEs can exacerbate diabetic and nondiabetic nephropathy [20,21]. Although obese rats develop
massive proteinuria, creatinine clearance is not reduced until
a very advanced age is reached [22,23]. Further studies are
needed to determine the influence of renal or hepatic
excretion on AGE levels and its consequences on the
myocardium.
Different mechanisms may be responsible for the
detrimental effect of accumulating AGEs on myocardial
structure and function. Firstly, modification of proteins
promoting myocardial contraction or relaxation may occur,
leading to impaired systolic or diastolic function and to
structural alterations, depending on the proteins involved
[24]. Secondly, AGEs may be able to promote transdifferentiation of epithelial cells to myofibroblasts via their
specific receptors (e.g., RAGE) [25]. Finally, activation of
RAGE promotes inflammation and oxidative stress, which
can decrease the bioavailability of nitric oxide. Among
many other effects, nitric oxide has been shown to improve
myocardial relaxation [26]. Thus, activation of RAGE can
have a direct functional impact on myocardial relaxation. It
is interesting to note that in the diabetic myocardium both
accumulated AGEs and their receptors seem to be predominantly localized in the coronary vasculature rather than in
the cardiomyocytes [17,27]. Thus, apart from the left
ventricular functional effects analysed in the present study,
the AGE – RAGE interaction may at least in part be
accountable for the accelerated rate of coronary artery
disease in diabetic patients [28]. Interestingly, the novel
AGE crosslink breaker ALT-711 has improved many
morphological features of cardiomyopathy in rats and dogs
with hypo-insulinaemic diabetes [29,30], further strengthening the concept of AGE-induced myocardial dysfunction as
an underlying cause of diabetic cardiomyopathy.
In summary, using load independent indices of LV
function, we have shown that functional impairment of
the type 2 diabetic myocardium is characterized by a
predominant prolongation of relaxation. The correlation
between myocardial AGE content and LV relaxation
supports a specific pathogenetic role of AGEs in diabetic
cardiomyopathy.
Acknowledgements
The authors wish to thank Gerald Fischer for excellent
technical support. The present study is part of the
‘‘Cardiovascular and Renal Endpoints in Diabetes
(CARED)’’ preclinical study program.
6
S. Schäfer et al. / The European Journal of Heart Failure 8 (2006) 2 – 6
References
[1] Bertoni AG, Tsai A, Kasper EK, Brancati FL. Diabetes and idiopathic
cardiomyopathy: a nationwide case-control study. Diabetes Care
2003;26:2791 – 5.
[2] Hayat SA, Patel B, Khattar RS, Malik RA. Diabetic cardiomyopathy: mechanisms, diagnosis and treatment. Clin Sci (Lond)
2004;107:539 – 57.
[3] Ahmed N. Advanced glycation endproducts — role in pathology of
diabetic complications. Diabetes Res Clin Pract 2005;67:3 – 21.
[4] Kilhovd BK, Berg TJ, Birkeland KI, Thorsby P, Hanssen KF. Serum
levels of advanced glycation end products are increased in patients
with type 2 diabetes and coronary heart disease. Diabetes Care
1999;22:1543 – 8.
[5] Schleicher ED, Wagner E, Nerlich AG. Increased accumulation of the
glycoxidation product N(epsilon)-(carboxymethyl)lysine in human
tissues in diabetes and aging. J Clin Invest 1997;99:457 – 68.
[6] Berg TJ, Snorgaard O, Faber J, Torjesen PA, Hildebrandt P, Mehlsen J,
et al. Serum levels of advanced glycation end products are associated
with left ventricular diastolic function in patients with type 1 diabetes.
Diabetes Care 1999;22:1186 – 90.
[7] Norton GR, Candy G, Woodiwiss AJ. Aminoguanidine prevents the
decreased myocardial compliance produced by streptozotocin-induced
diabetes mellitus in rats. Circulation 1996;93:1905 – 12.
[8] Weisfeldt ML, Frederiksen JW, Yin FC, Weiss JL. Evidence of
incomplete left ventricular relaxation in the dog: prediction from the
time constant for isovolumic pressure fall. J Clin Invest 1978;62:
1296 – 302.
[9] Boehm BO, Schilling S, Rosinger S, Lang GE, Lang GK, KientschEngel R, et al. Elevated serum levels of N(epsilon)-carboxymethyllysine, an advanced glycation end product, are associated with
proliferative diabetic retinopathy and macular oedema. Diabetologia
2004;47:1376 – 9.
[10] Zabalgoitia M, Ismaeil MF, Anderson L, Maklady FA. Prevalence of
diastolic dysfunction in normotensive, asymptomatic patients with
well-controlled type 2 diabetes mellitus. Am J Cardiol 2001;87:
320 – 3.
[11] Poirier P, Bogaty P, Garneau C, Marois L, Dumesnil JG. Diastolic
dysfunction in normotensive men with well-controlled type 2 diabetes:
importance of maneuvers in echocardiographic screening for preclinical diabetic cardiomyopathy. Diabetes Care 2001;24:5 – 10.
[12] Cosson S, Kevorkian JP. Left ventricular diastolic dysfunction: an
early sign of diabetic cardiomyopathy. Diabetes Metab 2003;29:
455 – 66.
[13] Zhou YT, Grayburn P, Karim A, Shimabukuro M, Higa M, Baetens D,
et al. Lipotoxic heart disease in obese rats: implications for human
obesity. Proc Natl Acad Sci U S A 2000;97:1784 – 9.
[14] Iltis I, Kober F, Desrois M, Dalmasso C, Lan C, Portha B, et al.
Defective myocardial blood flow and altered function of the left
ventricle in type 2 diabetic rats: a noninvasive in vivo study using
perfusion and cine magnetic resonance imaging. Invest Radiol
2005;40:19 – 26.
[15] Fredersdorf S, Thumann C, Ulucan C, Griese DP, Luchner A, Riegger
GA, et al. Myocardial hypertrophy and enhanced left ventricular
contractility in Zucker diabetic fatty rats. Cardiovasc Pathol 2004;13:
11 – 9.
[16] Ren J, Sowers JR, Walsh MF, Brown RA. Reduced contractile
response to insulin and IGF-I in ventricular myocytes from genetically
obese Zucker rats. Am J Physiol Heart Circ Physiol 2000;279:
H1708 – 14.
[17] Schalkwijk CG, Baidoshvili A, Stehouwer CD, van Hinsbergh VW,
Niessen HW. Increased accumulation of the glycoxidation product N
epsilon-(carboxymethyl)lysine in hearts of diabetic patients: generation and characterisation of a monoclonal anti-CML antibody.
Biochim Biophys Acta 2004;1636:82 – 9.
[18] Sebekova K, Kupcova V, Schinzel R, Heidland A. Markedly elevated
levels of plasma advanced glycation end products in patients with liver
cirrhosis — amelioration by liver transplantation. J Hepatol 2002;36:
66 – 71.
[19] Sebekova K, Blazicek P, Syrova D, Krivosikova Z, Spustova V,
Heidland A, et al. Circulating advanced glycation end product levels
in rats rapidly increase with acute renal failure. Kidney Int, Suppl
2001;78:S58 – 62.
[20] Sebekova K, Faist V, Hofmann T, Schinzel R, Heidland A. Effects of a
diet rich in advanced glycation end products in the rat remnant kidney
model. Am J Kidney Dis 2003;41:S48 – 51.
[21] Zheng F, He C, Cai W, Hattori M, Steffes M, Vlassara H. Prevention
of diabetic nephropathy in mice by a diet low in glycoxidation
products. Diabetes Metab Res Rev 2002;18:224 – 37.
[22] Schäfer S, Linz W, Bube A, Gerl M, Huber J, Kürzel GU, et al.
Vasopeptidase inhibition prevents nephropathy in Zucker diabetic fatty
rats. Cardiovasc Res 2003;60:447 – 54.
[23] Erdely A, Freshour G, Maddox DA, Olson JL, Samsell L, Baylis C.
Renal disease in rats with type 2 diabetes is associated with decreased
renal nitric oxide production. Diabetologia 2004;47:1672 – 6.
[24] Cooper ME. Importance of advanced glycation end products in
diabetes-associated cardiovascular and renal disease. Am J Hypertens
2004;17:31S – 8S.
[25] Oldfield MD, Bach LA, Forbes JM, Nikolic-Paterson D, McRobert A,
Thallas V, et al. Advanced glycation end products cause epithelialmyofibroblast transdifferentiation via the receptor for advanced
glycation end products (RAGE). J Clin Invest 2001;108:1853 – 63.
[26] Paulus WJ, Vantrimpont PJ, Shah AM. Acute effects of nitric oxide on
left ventricular relaxation and diastolic distensibility in humans.
Assessment by bicoronary sodium nitroprusside infusion. Circulation
1994;89:2070 – 8.
[27] Sun M, Yokoyama M, Ishiwata T, Asano G. Deposition of advanced
glycation end products (AGE) and expression of the receptor for AGE
in cardiovascular tissue of the diabetic rat. Int J Exp Pathol
1998;79:207 – 22.
[28] Naka Y, Bucciarelli LG, Wendt T, Lee LK, Rong LL, Ramasamy R, et
al. RAGE axis: animal models and novel insights into the vascular
complications of diabetes. Arterioscler Thromb Vasc Biol 2004;24:
1342 – 9.
[29] Candido R, Forbes JM, Thomas MC, Thallas V, Dean RG, Burns WC,
et al. A breaker of advanced glycation end products attenuates
diabetes-induced myocardial structural changes. Circ Res 2003;92:
785 – 92.
[30] Liu J, Masurekar MR, Vatner DE, Jyothirmayi GN, Regan TJ, Vatner
SF, et al. Glycation end-product cross-link breaker reduces collagen
and improves cardiac function in aging diabetic heart. Am J Physiol
Heart Circ Physiol 2003;285:H2587 – 91.