High-density lipoprotein (HDL) antioxidant capacity (HDL-AC)

High-density lipoprotein (HDL) antioxidant capacity refers to the functional ability of HDL particles to protect against the oxidative modification of other lipoproteins, particularly low-density lipoprotein (LDL) [PMID: 21903332]. This protective capacity is not determined by HDL concentration alone but by its composition of specific proteins and enzymes, most notably paraoxonase 1 (PON1), apolipoprotein A-I (ApoA-I), and lecithin-cholesterol acyltransferase (LCAT) [PMID: 17452741]. In healthy states, HDL prevents the accumulation of lipid hydroperoxides, thereby inhibiting the inflammatory response and the subsequent development of atherosclerotic plaques [PMC4449646]. In various disease states like diabetes or systemic inflammation, HDL can become "dysfunctional," losing its antioxidant capacity and potentially becoming pro-oxidant [PMID: 25149428]. While traditional therapies like statins, fibrates, and niacin can modestly improve HDL function, many drugs that successfully raise HDL-C levels have failed to demonstrate clinical benefit, leading the industry to focus on improving HDL's functional quality as a therapeutic target. Consequently, measuring HDL antioxidant capacity is considered a more accurate reflection of cardiovascular risk than simple HDL-C quantification [StatPearls: Lipoprotein Classification].

Other names

HDL antioxidant functionAnti-oxidative activity of high-density lipoproteinHDL-mediated LDL-oxidation inhibitionParaoxonase 1 activity

Enhancement of HDL-associated enzyme activity (specifically Paraoxonase 1) and increase in Apolipoprotein A-I levels to facilitate the neutralization of reactive oxygen species and lipid hydroperoxides on LDL particles.