Lipoprotein-Associated Phospholipase A2 (Lp-PLA2)

Definition

• Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a 45-kDa protein enzyme produced by inflammatory cells and activated endothelial cells. It travels in the blood mainly with LDLs. Lp-PLA2 hydrolyzes oxidized phospholipids in LDLs, resulting in formation of oxidized free fatty acids and lysophosphatidylcholine, which is proatherogenic. Alternate name is platelet-activating factor acetylhydrolase (PAF-AH).

Use

• Lp-PLA2 is considered a risk marker rather than a risk factor for cardiac heart disease. In conjunction with hsCRP assay can reliably stratify low-, intermediate-, and high-risk populations. Increased Lp-PLA2 with low LDL-C increases risk of heart disease two times. Increased Lp-PLA2 with high CRP increases risk of heart disease three times. Consensus panel recommendations are for Lp-PLA2 assessment in moderate-risk individuals for CHD either independently or in conjunction with hsCRP.

Interpretation

• Concentrations ≥235 ng/mL are associated with increased risk of cardiovascular events, including myocardial infarction and ischemic stroke, and are predictive of short-term mortality in myocardial infarction patients.
• Elevated Lp-PLA2 has been found to be associated with ischemic stroke and may be useful in risk assessment.

Limitations

• Smoking increases Lp-PLA2 measurements.

Suggested Reading

1Corson ‚ MA, Jones ‚ PH, Davidson ‚ MH. Review of the evidence for the clinical utility of lipoprotein-associated phospholipase A2 as a cardiovascular risk marker. Am J Cardiol. 2008;101(12A):41F " “50F.