[Role of high density lipoproteins (HDL) in reverse cholesterol transport].

The atheromatous risk is negatively correlated with the plasma concentration of HDL cholesterol. This might be due to the role of HDL in the reverse cholesterol transport. In the first stage, free cholesterol molecules from peripheral cells are taken up by HDL through a receptor-dependent mechanism. In HDL, the esterification of cholesterol is catalysed by the lecithin: cholesterol acyl transferase. The progressive accumulation of cholesterol esters leads to the formation of HDL2. Through the action of cholesterol ester transfer protein, HDL2 become enriched in triglycerides and transfer cholesterol esters to LDL. Finally, cholesterol may be taken up by the liver through two routes which are: the receptor-mediated LDL endocytosis and the direct uptake of cholesterol esters which occurs during the degradation of HDL2 by hepatic lipase.