Probucol, high-density lipoprotein metabolism and reverse cholesterol transport

Accumulation of cholesterol within the arterial wall reflects an imbalance between delivery and efflux. Monocyte-derived macrophages play a major role in arterial wall cholesterol accumulation. Using tracer methodology in a rabbit model, several investigators have estimated the rate of cholesterol delivery and thus the steady-state rate of efflux to be between 0.4 and 2.4 μ g/cm 2 /hour. The process responsible for arterial wall cholesterol efflux, “reverse cholesterol transport,” can be conceptualized as a sequence of events including (1) loss of cell cholesterol, (2) intravascular cholesterol transport, (3) hepatic cholesterol uptake, and (4) biliary secretion. Work by many investigators has characterized these individual processes.