The effects of cholestyramine on high density lipoprotein metabolism

This study on 4 type II hyperlipoproteinaemic subjects examines the effects of pharmacologic doses (8 g twice daily) of the bile acid sequestrant cholestyramine on the plasma distribution and chemical composition of the high density lipoprotein subfractions, HDL2 and HDL3, and describes the influence of the drug on the metabolism of the major HDL aporoteins, apolipoprotein A-I and A-II. Cholestyramine lowered plasma low density lipoprotein cholesterol (32%; P less than 0.05) without affecting the level of that lipid in very low density or high density lipoproteins. However, the plasma HDL2/HDL3 ratio and apolipoprotein A-I concentration rose significantly on treatment, while apolipoprotein A-II remained unchanged. The rise in apolipoprotein A-I derived from an increase in its synthetic rate and produced a relative enrichment of the protein with respect to apolipoprotein A-II in both HDL subfractions. These results demonstrate the cholestyramine treatment affects HDL metabolism in a way which, according to current concepts, may prove beneficial to the recipient.