Lp-PLA2 is one of the subtypes of phospholipase superfamily, also known as platelet activating factor acetylhydrolase, which is secreted by macrophages, T cells and mast cells in vascular intima. Lp-PLA2 expression was up-regulated in atherosclerotic plaque and strongly expressed in macrophages of vulnerable plaque fibrous cap. Lp-PLA2 can hydrolyze oxidized phospholipids in ox LDL to produce lipid pro-inflammatory substances, such as hemolytic lecithin and oxidized free fatty acids, and then produce a variety of atherogenic effects, including endothelial cell death and endothelial dysfunction, and stimulate the production of adhesion factors and cytokines. These substances can further produce self reinforcing circulation through chemotactic inflammatory cells and produce more proinflammatory substances.

Lp-PLA2 released into the blood circulation mainly binds to apolipoprotein (apo) B-rich lipoproteins, with low-density lipoprotein (LDL) accounting for 80%, and the rest binds to high-density lipoprotein (HDL), lipoprotein a [Lp (a)] and very low-density lipoprotein (VLDL). In patients with atherosclerotic diseases, the level of Lp-PLA2 was positively correlated with the level of LDL subfraction.