Lipoprotein-associated phospholipase A2

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

Function
In the blood it travels mainly with is_associated_with::low-density lipoprotein (LDL). Less than 20% is associated with is_associated_with::high-density lipoprotein HDL. It is an enzyme produced by is_associated_with::inflammatory cells and hydrolyzes oxidized is_associated_with::phospholipids in LDL.

Lp-PLA2 is platelet-activating factor (PAF) acetylhydrolase (EC 3.1.1.47), 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 is_associated_with::atherosclerosis, an observation that has prompted interest as a possible therapeutic target (see, e.g. the investigational drug is_associated_with::Darapladib). In human atherosclerotic lesions, 2 main sources of Lp-PLA2 can be identified, including that which is brought into the is_associated_with::intima bound to LDL (from the circulation), and that which is synthesized de novo by plaque inflammatory cells (is_associated_with::macrophages, T cells, mast cells)."

It is used as a marker for cardiac disease.

A is_associated_with::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 is_associated_with::coronary heart disease and is_associated_with::stroke.