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Proc Natl Acad Sci U S A. 2004 Sep 14;101(37):13624-9. Epub 2004 Sep 3.

Hyperleptinemia prevents lipotoxic cardiomyopathy in acyl CoA synthase transgenic mice.

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1
Gifford Laboratories, Touchstone Center for Diabetes Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-8854, USA.

Abstract

The physiologic function of the progressive hyperleptinemia of diet-induced obesity is unknown. However, that lipotoxicity in nonadipose tissues of congenitally unleptinized obese rodents is far greater than in hyperleptinemic diet-induced obesity rodents has suggested an antilipotoxic role. To test this hypothesis, mice with severe lipotoxic cardiomyopathy, induced transgenically by cardiomyocyte-specific overexpression of the acyl CoA synthase (ACS) gene, were made hyperleptinemic by treatment with recombinant adenovirus containing the leptin cDNA. Normoleptinemic control ACS-transgenic mice developed severe dilated cardiomyopathy with thickened left ventricular walls and profound impairment of systolic function on echocardiogram; histologically, there was severe myofiber disorganization and interstitial fibrosis, with intracytoplasmic lipid vacuoles identifiable by electron microscope. By contrast, the hearts of hyperleptinemic ACS-transgenic mice appeared normal, with normal echocardiograms and cardiac triglyceride (TG) contents. Their lower myocardial TG content was ascribed primarily to profound lowering of plasma TG and free fatty acids; free fatty acids were 17% of normal at 8 weeks. Additionally, enhanced myocardial AMP-activated protein kinase phosphorylation may have increased fatty acid oxidation, thereby contributing to the lowering of lipid stores. We conclude that obesity-level hyperleptinemia protects the heart from lipotoxicity.

PMID:
15347805
PMCID:
PMC518804
DOI:
10.1073/pnas.0405499101
[Indexed for MEDLINE]
Free PMC Article
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