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Lipotoxic heart disease in obese rats: implications for human obesity

Author:
Zhou, Y.T., Grayburn, P., Karim, A., Shimabukuro, M., Higa, M., Baetens, D., Orci, L., Unger, R.H.
Source:
Proceedings of the National Academy of Sciences of the United States of America 2000 v.97 no.4 pp. 1784-1789
ISSN:
0027-8424
Subject:
rats, obesity, myocardium, triacylglycerols, sphingolipids, apoptosis, heart diseases, oxygenases, transcription factors, messenger RNA, enzymes, fatty acids, oxidation, electrocardiography, cytoplasmic inclusions, drugs, nitric oxide synthase
Abstract:
To determine the mechanism of the cardiac dilatation and reduced contractility of obese Zucker Diabetic Fatty rats, myocardial triacylglycerol (TG) was assayed chemically and morphologically. TG was high because of underexpression of fatty acid oxidative enzymes and their transcription factor, peroxisome proliferator-activated receptor-alpha. Levels of ceramide, a mediator of apoptosis, were 2-3 times those of controls and inducible nitric oxide synthase levels were 4 times greater than normal. Myocardial DNA laddering, an index of apoptosis, reached 20 times the normal level. Troglitazone therapy lowered myocardial TG and ceramide and completely prevented DNA laddering and loss of cardiac function. In this paper, we conclude that cardiac dysfunction in obesity is caused by lipoapoptosis and is prevented by reducing cardiac lipids.
Agid:
2357765