Oxidized LDL (oxLDL)

Oxidized LDL (oxLDL) refers to LDL particles in which the polyunsaturated fatty acids and apolipoprotein B-100 have undergone oxidative modification, typically within the subendothelial space where LDL is retained and exposed to reactive oxygen species and lipoxygenases. oxLDL is not recognised by the LDL receptor but is avidly taken up by macrophage scavenger receptors (SR-A, CD36), driving foam cell formation — the hallmark of early atherosclerotic lesions. Circulating oxLDL, measured by immunoassays using antibodies such as 4E6 or E06 that recognise oxidised phosphatidylcholine epitopes, is elevated in subjects with coronary artery disease, metabolic syndrome, and type 2 diabetes. As a direct indicator of lipid oxidation at the vessel wall, oxLDL is conceptually distinct from F2-isoprostanes (a systemic oxidative stress index) and from LDL-C or LDL-P, which do not reflect oxidative modification.