Out muscling cholesterol

A new UQ study has proved that muscle tissue plays a vital role in regulating cholesterol levels in the body with implications for diseases like atherosclerosis, cardiovascular disease, obesity, and diabetes.

The Institute for Molecular Bioscience (IMB) study demonstrates that muscle is an important regulator of HDL (good) cholesterol levels and is a potential target for novel drugs.

IMB`s National Health and Medical Research Council (NHMRC) Principal Research Fellow Dr George Muscat said high cholesterol was caused by an imbalance in cholesterol absorption and excretion resulting in deposits of “bad” cholesterol (LDL cholesterol) in arteries, often leading to heart attacks or strokes.

"Recent studies characterised a family of receptors called Liver X Receptors (LXRs) that have a dynamic role in regulating genes involved in fat and cholesterol metabolism in the body," Dr Muscat said.

"Previously we thought the liver was the primary organ for maintaining cholesterol at appropriate levels in the body, but we now know that LXR is expressed in muscle and regulates the expression of genes that control cholesterol levels.

"Activation of LXR in muscle tissue induces transport of excess cholesterol and lipids to the liver for breakdown and excretion.

"Our work explains the genetics behind previously published data demonstrating a correlation between exercise, percentage muscle mass, levels of good cholesterol (HDL cholesterol) and the reduced incidence of cardio-vascular disease.

"And with muscle accounting for about 40 percent of a person`s body weight, it is obviously a vital site for cholesterol regulation in the body.

"This work also has important implications for patients affected by elevated cholesterol levels, because the modulation of LXR using drugs may block, or even reverse, the process of heart disease."

The team of researchers involved in the study between 2000 and 2002 includes the IMB`s Dr Muscat and Mr Paul Rode.

Media: For more information contact Russell Griggs (07 3365 1805) or Helen Weatherley (0421 056 098) at the IMB.