Figure 2.

High-density lipoprotein (HDL) functionality. HDL performs various functions that cannot be inferred solely by measuring HDL cholesterol (HDLc) or apolipoprotein A-1. These functions link HDL to cardiovascular protection and its role in the pathophysiology of several chronic and acute diseases. (1) HDL mediates reverse cholesterol transport, removing excess cellular cholesterol and oxysterols (including from macrophages infiltrated in the arterial intima) and promoting its trafficking to the liver for elimination via bile and feces; (2) diminishes the inflammatory response by minimizing the transcription of inflammatory genes; (3) reduces LDL oxidation, decreasing its uptake by macrophages; (4) stabilizes atherosclerotic lesions by carrying protease inhibitors; (5) promotes vasodilation by enhancing nitric oxide (NO) release from the endothelium; (6) transports microRNAs and delivers them to target cells, regulating protein expression; and (7) supports glycemic homeostasis by positively modulating insulin sensitivity. These functions may be compromised in ARDs contributing to CDV. Abbreviations: ABCA-1, ATP-binding cassette transporter A-1; ABCG-1, ATP-binding cassette transporter G-1; CD-36, cluster of differentiation 36—member of class B scavenger receptor; LOX-1, lectin-type oxidized low-density lipoprotein (LDL) receptor-1; SR-B1, scavenger receptor class B type 1 (parts of the figure were obtained from https://smart.servier.com).