[The role of apolipoproteins A-I and A-II in plasma HDL remodeling]

Apolipoprotein (apo) A-I is a key HDL protein participating in the process of reverse cholesterol transport. A small part of plasma apo A-I exists as free protein which is a substrate for generation of discoid HDL precursors, containing small amounts of phospholipids and free cholesterol. The cycling of apo A-I between precursor and mature forms of HDL is an essential element of HDL remodeling in plasma. The second most abundant protein of human HDL is apo A-II, nevertheless, it is present only in about half of the HDL particles in plasma. The mechanism mediating the formation of HDL containing apo A-I and apo A-II is unknown. The role of apo A-II in reverse cholesterol transport generates controversy. Different observations indicate either proatherogenic or proinflammatory properties of apo A-II. Also the participation of apo A-II in plasma HDL remodeling remains unclear. Apo A-II maybe a factor stabilizing HDL particles. This protein may also take part in regulation of VLDL metabolism. The review presents current knowledge concerning participation of apo A-I and apo A-II in plasma HDL remodeling.