The paradox of dysfunctional high-density lipoprotein.

This review addresses how, in atherosclerosis or systemic inflammation, HDL can lose its usual atheroprotective characteristics and even paradoxically assume proinflammatory properties. Specific chemical and structural changes within HDL particles can impede reverse cholesterol transport, enhance oxidation of LDL, and increase vascular inflammation. HDL may be viewed as a shuttle that can be either anti-inflammatory or proinflammatory, depending on its cargo of proteins, enzymes, and lipids. Some therapeutic approaches that reduce coronary risk, such as statins and therapeutic lifestyle changes, can favorably moderate the characteristics of proinflammatory HDL. In addition, apolipoprotein A-I mimetic peptides and other compounds that target functional aspects of HDL may offer novel approaches to reduction in cardiovascular risk. Current data suggest that under some conditions HDL can become dysfunctional and even proinflammatory, but this characterization can change with resolution of systemic inflammation or use of certain treatments.