Clinical

High intrahepatic triglyceride content a marker of insulin resistance

Last Updated: 2008-06-27 16:34:27 -0400 (Reuters Health)

By Martha Kerr

NEW YORK (Reuters Health) - An international team of investigators reports that elevated intrahepatic triglyceride (IHTG) content is inversely correlated with plasma insulin concentration and positively associated with impaired insulin action.

Dr. Kevin M. Korenblat of Washington University School of Medicine in St. Louis, Missouri, and colleagues used a euglycemic clamp procedure in 42 nondiabetic obese subjects (mean body mass index of 36) with an IHTG content ranging from 1%-46%, to determine the relationship between IHTG and insulin action in the liver, muscle and fat.

"Hepatic insulin sensitivity, assessed as a function of glucose production rate and plasma insulin concentration, was inversely correlated with IHTG content," Dr. Korenblat's team reports in the May issue of Gastroenterology.

"The ability of insulin to suppress fatty acid release from adipose tissue and to stimulate glucose uptake by skeletal muscle were also inversely correlated with IHTG content."

Multivariate analyses showed that IHTG content predicted insulin action in liver, skeletal muscle, and adipose tissue. This was independent of BMI and percent body fat, "and accounted for 34%, 42%, and 44% of the variability in these tissues, respectively," the researchers report.

"Nonalcoholic fatty liver disease should be considered part of a multi-organ system derangement in insulin sensitivity," they conclude.

"IHTG is an important marker of insulin resistance which is a precursor for diabetes," Dr. Korenblat commented in an interview with Reuters Health.

To best manage the patient with elevated IHTG content, "we recommend a weight loss diet," Dr. Korenblat said. "Moderate weight loss, about 5% of initial body weight, markedly decreases intrahepatic triglyceride content."

"We are currently trying to understand the mechanisms responsible for IHTG accumulation and the mechanisms that link increased IHTG with insulin resistance and metabolic diseases," Dr. Korenblat said.

Gastroenterology 2008;134:1369-1375.