Lipoprotein-associated phospholipase A2 as a target of therapy.

Abstract

PURPOSE OF REVIEW:

Considerable discussion continues regarding the precise role that secreted lipoprotein-associated phospholipase A2 (Lp-PLA2), also called platelet-activating factor acetylhydrolase, plays in atherosclerosis. Since interest in this enzyme as a putative drug target has been based primarily upon its association with low-density lipoprotein (LDL) in human plasma, this review will focus on Lp-PLA2 and human coronary heart disease.

RECENT FINDINGS:

Recent reports have linked Lp-PLA2 enrichment not only to the most atherogenic of LDL particles but also to the most advanced, rupture-prone, plaques. Electronegative LDL has been shown to be highly enriched in Lp-PLA2; and in advanced atheroma, Lp-PLA2 levels are highly upregulated, colocalizing with macrophages in both the necrotic core and fibrous cap. Lp-PLA2 is well placed, whether on an oxidation susceptible LDL particle or in the highly oxidative environment of an advanced rupture-prone plaque, to hydrolyse oxidized phospholipid and generate significant quantities of the two pro-inflammatory mediators, lysophosphatidylcholine and oxidized nonesterified fatty acid. Several studies have confirmed that Lp-PLA2 is an independent risk factor for cardiovascular events (i.e. myocardial infarction and stroke). Although epidemiology studies consistently support a relationship between plasma Lp-PLA2 levels and susceptibility to coronary heart disease this is not the case for Lp-PLA2 polymorphisms. Two clinical studies have linked the Ala-379-->Val polymorphism with a reduced risk of myocardial infarction, but functional differences between the AA and VV polymorphs have yet to be demonstrated.

SUMMARY:

Lp-PLA2 is intimately associated with several aspects of human atherogenesis. Although various lipid-lowering therapies, such as statins, have been shown to reduce plasma levels of Lp-PLA2, none has been studied in terms of its ability to lower the large macrophage-mediated upregulation of Lp-PLA2 within advanced plaques.

• Authors: Colin H Macphee, Jeanenne J Nelson, Andrew Zalewski
• Journal: Current opinion in lipidology (Curr Opin Lipidol) Vol. 16 Issue 4 Pg. 442-6 (Aug 2005) ISSN: 0957-9672 [Print] England
• PMID: 15990594 (Publication Type: Journal Article, Review)

Chemical References

• Lovastatin
• Phospholipases A
• Phospholipases A2
• 1-Alkyl-2-acetylglycerophosphocholine Esterase

Topics

• 1-Alkyl-2-acetylglycerophosphocholine Esterase
• Cardiovascular Diseases (drug therapy, enzymology, etiology)
• Humans
• Lovastatin (therapeutic use)
• Macrophages (enzymology)
• Phospholipases A (antagonists & inhibitors, genetics, metabolism)
• Phospholipases A2