HIGH-DENSITY LIPOPROTEIN: ROLE IN REVERSE CHOLESTEROL TRANSPORT

High-density lipoprotein (HDL) mediates reverse cholesterol transport (RCT) through its potential to accept excess cholesterol from extrahepatic tissues, and delivers it to the liver for breakdown and excretion. HDL also has pleiotropic properties such as anti-apoptosis, anti-inflammation, and capacity to remove oxidized sterols and phospholipids from the circulation. HDL is composed of apolipoprotein A-I, the major lipoprotein and apolipoprotein A-II, the minor lipoprotein. For HDL to carry out reverse cholesterol transport, it has to transform to make it suitable for acceptance of cholesterol and phospholipids. Therefore, in this review, we explore the composition and the various sizes of HDL. Further, we review the biosynthesis and remodeling of HDL by various proteins, enzymes and receptors such as ATP-binding cassette transporter class B-1 (ABCA1), endothelial lipase (EL), scavenger receptor class B type I (SR-BI), cholesteryl ester transfer protein (CETP), lecithin cholesterol acyltransferase LCAT), and phospholipids transfer protein (PLTP). Finally, we describe the pathways involved in the removal of cholesterol from the peripheral tissue and the current therapeutic strategies to increase levels of HDL-C as well as their outcomes.