Cholesterol Transport Genes Identified

Researchers studying how the body controls cholesterol transport have found that two genes, Abcg5 and Abcg8, are required for efficient secretion of cholesterol into the bile for subsequent elimination from the body. Their findings were published November 20, 2002, in the online edition of the Proceedings of the National Academy of Sciences.

To study the role of the two genes, investigators from the University of Texas Southwestern Medical Center (Dallas, USA) genetically engineered a mouse line lacking the two genes. In the modified mice, they found that liver and plasma cholesterol levels were increased by as much as 18-fold and 2.4-fold, respectively, after a cholesterol-rich meal. Disruption of the two genes also resulted in a 30-fold increase in plasma levels of sitosterol, the major plant sterol, and a two- to three-fold increase in fractional absorption of dietary plant sterols.

"The disruption of the two genes, Abcg5 and Abcg8, reveals their crucial role in biliary cholesterol secretion,” explained first author Dr. Liqing Yu, an instructor in molecular genetics at UT Southwestern Medical Center. "In humans and mice, the secretion of cholesterol into the bile is essential for maintaining cholesterol homeostasis and constitutes a major defense against the accumulation of dietary cholesterol in blood and tissues.”





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