High Density Lipoprotein Particle Composition, Functionality, Deficiency, and Atherosclerotic Cardiovascular Disease Risk: A Review.

Purpose of review: Decreased serum high-density-lipoprotein-cholesterol (HDL-C), HDL particles, and cell-cholesterol-efflux-capacity have all been associated with increased atherosclerotic cardiovascular disease (ASCVD) risk. Our goals are to summarize recent findings with regard to these topics.

Recent findings: Apolipoprotein (apo) A1 containing HDL particles have been characterized by two-dimensional gel electrophoresis and apoA1 immunoblotting and range from very small preβ-1 HDL, small α-4 HDL, medium α-3 HDL to large and very large α-2 and α-1 HDL. Preβ-1 HDL are most efficient in serving as acceptors of free cholesterol and phospholipid from cells via ATP binding cassette transporter A1, while α-2 and α-1 HDL are most efficient in delivering cholesteryl-ester to the liver via scavenger receptor-B1 or to triglyceride-rich lipoproteins (TRL) in exchange for triglycerides via cholesteryl ester transfer protein (CETP). Recent research on the relationships of the lipid and protein composition, function, metabolism and levels of HDL particles to ASCVD risk will be reviewed, as will advances in potential therapeutic options. HDL particles are by far the most abundant lipoproteins in plasma and contain 110 proteins involved in lipid metabolism and immune function. ApoA1, apoA2, and all lipid classes are found in all HDL particles. Low levels of large and very large α-HDL and increased levels of very small preβ-1 HDL have been associated with increased ASCVD risk. The best therapeutic options for ASCVD risk reduction in patients with low HDL-C is optimizing other risk factors including low-density-lipoprotein (LDL)-C, small-dense LDL-C, plasma-glucose, body-mass-index, blood pressure, and the promotion of smoking cessation.