The hepatobiliary axis and lipoprotein metabolism: effects of bile acid sequestrants and ileal bypass surgery.

Cholesterol excretion from the body is achieved almost exclusively via the hepatobiliary axis. Disruption of the integrity of this pathway by interruption of the enterohepatic circulation produces profound changes in cholesterol metabolism that affect every body tissue. This is particularly evident in the liver and gut which are the major sources of this sterol in the plasma. Elevated plasma cholesterol levels have been implicated in the pathogenesis of atherosclerosis and, in consequence, strenuous efforts have been made to find appropriate hypocholesterolemic therapy to reduce this risk. Medical or surgical interruption of the enterohepatic circulation is, to date, the most successful means of lowering plasma cholesterol, and in this review we examine the ramifications of such therapy on lipid and lipoprotein metabolism in the liver, gut, and plasma.