Abdominal fat, the spare tire that many of us carry, has long been implicated as a primary suspect in causing the metabolic syndrome, a cluster of conditions that includes the most dangerous heart attack risk factors: prediabetes, diabetes, high blood pressure, and changes in cholesterol.

But with the help of powerful new imaging technologies, a team of Howard Hughes Medical Institute (HHMI) researchers at Yale University School of Medicine has found that insulin resistance in skeletal muscle leads to alterations in energy storage that set the stage for the metabolic syndrome.

Insulin resistance is a condition in which the body's cells become resistant to insulin, a hormone secreted by the pancreas that plays an essential role in regulating the carbohydrates, lipids, and proteins obtained from food.

The new study, published July 16, 2007, in the Proceedings of the National Academy of Sciences (PNAS), demonstrates that insulin resistance in skeletal muscle -- caused by decreased ability of muscle to make glycogen, the stored form of carbohydrate from food energy -- can promote an elevated pattern of lipids or fats in the bloodstream that underpins the metabolic syndrome.

The study was led by HHMI investigator Gerald I. Shulman and Kitt Falk Petersen, both of the Yale University School of Medicine. Coauthors of the paper were from Yale and Harvard Medical School.

The metabolic syndrome is a very common metabolic abnormality and the prevalence is growing. However, the underlying factors that cause it are poorly understood. The syndrome afflicts more than 50 million Americans and roughly half of all Americans are predisposed to it, making it one of the nation's most serious human health issues.

To begin to shed light on the earliest molecular events that lead to the metabolic syndrome, Shulman and his colleagues used powerful new magnetic resonance imaging techniques to observe how nutrients are channeled in the body i
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Contact: Jennifer Michalowski
michalow@hhmi.org
301-215-8576
Howard Hughes Medical Institute
16-Jul-2007