A team of researchers from the University of Pennsylvania Medical Center and Rhone-Poulenc Rorer has identified a new human gene that may figure prominently in the regulation of cholesterol levels in the body. When the gene was experimentally overexpressed in mice, levels of the form of cholesterol called high-density lipoprotein, or HDL, dropped to nearly undetectable levels, a condition that would be associated with high cardiovascular disease risk in humans. A report on the new findings appears in the April issue of Nature Genetics.
"HDL is a very powerful protector against heart disease and stroke, and we think this new gene could be a major player in determining HDL levels," says Daniel J. Rader, MD, an assistant professor of medicine and senior author on the report. "Too much activity on the part of this gene, for whatever reason, might lead to lowered HDL levels and higher cardiovascular disease risk."
While high overall levels of cholesterol in the blood have long been linked to elevated cardiovascular disease risk, two distinct forms of cholesterol are involved, each performing different duties in the body. Low-density lipoprotein (LDL) - sometimes called the bad cholesterol - is produced by the liver and ferries fats to the muscles, the heart, and other tissues. Unchecked, this process can lead to the formation of dangerous deposits in the arteries that can disrupt or block blood flow. HDL - referred to as the good cholesterol -- is also produced by the liver and is responsible for returning fats from tissues in the body to the liver for reprocessing or elimination. Dramatically lowered HDL levels could, therefore, lead to a health crisis in time.
Scientists have known that at least 50 percent of the variation in HDL
cholesterol levels in the body depends on genetic factors. The specific genes
involved have been unknown, however, so the current findings represent a
potentially important advance toward understanding processes that co
Contact: Franklin Hoke
University of Pennsylvania School of Medicine