Liver Fat, Not Visceral Fat, Linked to Obesity

Study suggests altered metabolism may be due to changes in fatty acid transport

MONDAY, Aug. 31 (HealthDay News) -- High levels of intrahepatic fat correlate better with metabolic changes associated with obesity than visceral fat, according to a study published online Aug. 24 in the Proceedings of the National Academy of Sciences.

Elisa Fabbrini, M.D., from the Washington University School of Medicine in St. Louis, and colleagues studied 20 obese individuals who were matched on visceral adipose tissue (VAT) content and had either low or high intrahepatic triglyceride (IHTG), and 20 obese individuals who were matched on IHTG content and had either low or high VAT.

In individuals matched for VAT who had higher IHTG content, the researchers found that hepatic insulin sensitivity was 41 percent lower, adipose insulin sensitivity was 13 percent lower, and muscle insulin sensitivity was 36 percent lower. In addition, the very-low-density lipoprotein-triglyceride secretion rate was nearly double. Expression of CD36, which regulates tissue free fatty acid uptake from plasma, was significantly lower in adipose tissue and significantly higher in skeletal muscle.

"These data demonstrate that IHTG, not VAT, is a better marker of the metabolic derangements associated with obesity," Fabbrini and colleagues conclude. "Furthermore, alterations in tissue fatty acid transport could be involved in the pathogenesis of ectopic triglyceride accumulation by redirecting plasma fatty acid uptake from adipose tissue toward other tissues."

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