Impaired contractile function and mitochondrial respiratory capacity in response to oxygen deprivation in a rat model of pre-diabetes

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Title Impaired contractile function and mitochondrial respiratory capacity in response to oxygen deprivation in a rat model of pre-diabetes
Author Essop, M. F.; Chan, W. Y. Anna; Valle, A.; García-Palmer, F. J.; Du Toit, Eugene
Journal Name Acta Physiologica
Year Published 2009
Place of publication United Kingdom
Publisher Wiley-Blackwell Publishing
Abstract Aim: Obesity is a major contributor to the global burden of disease and is closely associated with the development of type 2 diabetes and cardiovascular diseases. This study tested the hypothesis that mitochondrial respiratory capacity of the pre-diabetic heart is decreased leading to impaired contractile function and tolerance to ischaemia/reperfusion. Methods: Eight-week-old male Wistar rats were fed a high caloric diet for 16 weeks after which anthropometric, metabolic, cardiac and mitochondrial parameters were evaluated vs. age-matched lean controls. Cardiac function (working heart perfusions) and mitochondrial respiratory capacity were assessed at baseline and in response to acute oxygen deprivation. Results: Rats fed the high caloric diet exhibited increased body weight and visceral fat vs. the control group. Heart weights of obese rats were also increased. Triglyceride, fasting plasma insulin and free fatty acid levels were elevated, while high-density lipoprotein cholesterol levels were reduced in the obese group. Contractile function was attenuated at baseline and further decreased after subjecting hearts to ischaemia-reperfusion. Myocardial infarct sizes were increased while ADP phosphorylation rates were diminished in obese rats. However, no differences were found for mtDNA levels and the degree of oxidative stress-induced damage. Conclusions: These data show that decreased mitochondrial bioenergetic capacity in pre-diabetic rat hearts may impair respiratory capacity and reduce basal contractile function and tolerance to acute oxygen deprivation. Keywords metabolic syndrome, mitochondrial respiration, myocardial infarction, obesity.
Peer Reviewed Yes
Published Yes
Alternative URI http://dx.doi.org/10.1111/j.1748-1716.2009.02024.x
Copyright Statement Author Posting. Copyright 2009 The Authors. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Acta Physiologica, Volume 197, Issue 4,289-296, 10.1111/j.1748-1716.2009.02024.x
Volume 197
Issue Number 4
Page from 289
Page to 296
ISSN 1748-1708
Date Accessioned 2010-06-23
Date Available 2010-10-04T06:53:54Z
Language en_AU
Research Centre Griffith Health Institute; Heart Foundation Research Centre
Faculty Griffith Health Faculty
Subject Physiology
URI http://hdl.handle.net/10072/34247
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1x

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