Lipoprotein-associated phospholipase A2


Lipoprotein-associated phospholipase A2 also known as platelet-activating factor acetylhydrolase is a phospholipase A2 enzyme that in humans is encoded by the PLA2G7 gene. Lp-PLA2 is a 45-kDa protein of 441 amino acids. It is one of several PAF acetylhydrolases.

Function

In the blood Lp-PLA2 travels mainly with low-density lipoprotein. Less than 20% is associated with high-density lipoprotein HDL. Several lines of evidence suggest that HDL-associated Lp-PLA2 may substantially contribute to the HDL antiatherogenic activities. It is an enzyme produced by inflammatory cells and hydrolyzes oxidized phospholipids in LDL.
Lp-PLA2 is platelet-activating factor acetylhydrolase, a secreted enzyme that catalyzes the degradation of PAF to inactive products by hydrolysis of the acetyl group at the sn-2 position, producing the biologically inactive products LYSO-PAF and acetate.

Clinical significance

Lp-PLA2 is involved in the development of atherosclerosis, an observation that has prompted interest as a possible therapeutic target. In human atherosclerotic lesions, 2 main sources of Lp-PLA2 can be identified, including that which is brought into the intima bound to LDL, and that which is synthesized de novo by plaque inflammatory cells."
It is used as a marker for cardiac disease.
A meta-analysis involving a total of 79,036 participants in 32 prospective studies found that Lp-PLA2 levels are positively correlated with increased risk of developing coronary heart disease and stroke.