High-density lipoprotein particle size (HDL particle size)

High-density lipoprotein particle size refers to the diameter of spherical or discoidal HDL complexes circulating in plasma, ranging from 5 to 17 nm[1][3][5][6]. HDL particles are assembled from apolipoproteins (mainly apoA-I), phospholipids, cholesterol, and other minor proteins and undergo dynamic remodeling by enzymes such as CETP, PLTP, and hepatic lipase, which determine their size, composition, and function[1][5][7]. HDL particle size distribution (small, medium, and large) is measured clinically by NMR, gel electrophoresis, or ultracentrifugation, and has strong correlations with cardiovascular risk—large HDL particle concentration is inversely, and small HDL particle concentration is positively, associated with atherosclerosis and mortality[2][4][8]. Although HDL particle size is used as a clinical biomarker and surrogate endpoint in drug trials, it is not a discrete molecular entity but a measurable phenotype resulting from the activity of multiple HDL-associated proteins, lipid transporters, and remodeling enzymes[1][5][6][7].

Other names

HDL sizeHDL particle diameterHDL subfraction size (e.g., HDL2b, HDL3c)

CETP inhibitors reduce cholesteryl ester transfer from HDL to other lipoproteins, thereby increasing large HDL population and mean HDL particle size[4][7]. Niacin inhibits hepatic diacylglycerol acyltransferase-2, reducing VLDL production and enhancing HDL particle size. Fibrates activate PPARα, increasing smaller HDL particles through increased lipoprotein lipase activity[4]. Statins indirectly increase HDL particle number through effects on LDL and VLDL, with minor impact on particle size[4].