ABSTRACT
BACKGROUND: High density lipoprotein cholesterol (HDL-C) is popularly known as "good cholesterol" due to its ability to protect against atherosclerosis. High density lipoprotein (HDL) is best known as a key player to promote efflux of cholesterol from cells and promote reverse cholesterol transport (RCT) which decreases the accumulation of foam cells in arterial walls. Several roles of HDL discovered recently include anti-oxidant effect, anti-inflammatory role, and anti-thrombotic role, all of which potentiate the athero-protective role of HDL. METHOD: Relevant articles published in this field in various books, journals and on the websites of PubMed Central and National Library of Medicine were assessed to create a literature review article. RESULT: Besides reverse cholesterol transport, the antioxidant and anti-inflammatory properties of HDL may also play a major role in protection against development of atherosclerosis. Two different scales define the atheroprotective effects of HDL-quantity of HDL-C (measured in mg/deciliter or mmol/L) is inversely correlated with cardiovascular risk, the other is the quality or 'functionality' of HDL. CONCLUSION: The changes in HDL composition (primarily in protein components-apolipoproteins, paraoxonase etc.) can occur under pathological conditions and can affect the functionality of HDL. Thus, treatment alternatives to elevations in HDL-C must also involve strategies to maintain or enhance functionality of HDL. This literature review article discusses about the various athero-protective roles of HDL and the effects of changes in composition on its function.
