Statins and Metabolism of High Density Lipoprotein

Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol biosynthesis. Statins are widely and successfully used for lowering plasma cholesterol levels causing up to 45% reduction of plasma cholesterol and considerable reduction in risk of cardiovascular diseases. The main atheroprotective action of statins is reduction of plasma low density lipoprotein levels due to improved clearance of this lipoprotein by the liver. In addition, statins cause mild elevation of high density lipoprotein (HDL) concentration, but the mechanism responsible for this effect of statins on HDL metabolism is not well understood. It has been hypothesized that statins affect the HDL level through inhibition of cholesteryl ester transfer protein activity or by stimulating apolipoprotein A-I synthesis. Increased cholesterol efflux from liver due to raised expression of the ABCA1 transporter may also elevate HDL levels. Whereas raising the plasma HDL-C concentration may contribute to the atheroprotective effect of statins, its magnitude is uncertain and additional mechanisms that improve the functionality of HDL may be equally or more important. In this review we analyze what is currently known about effect of statins on HDL metabolism and on reverse cholesterol transport in particular.