Distinctiveness of secretory phospholipase A2 group IIA and V suggesting unique roles in atherosclerosis.

Clinical observations strongly support an association of circulating levels of secretory phospholipases A(2) (sPLA(2)) in atherosclerotic cardiovascular disease (ACVD). Two modes of action can provide causal support for these statistical correlations. One is the action of the enzymes on circulating lipoproteins and the other is direct action on the lipoproteins once in the arterial extracellular intima.

Secretory phospholipase A2 group V: lesion distribution, activation by arterial proteoglycans, and induction in aorta by a Western diet.

Objective: To study the distribution of group V secretory phospholipase A2 (sPLA2) in human and mouse lesions and compare its expression by human vascular cells, its activity toward lipoproteins, and the interaction with arterial proteoglycans (proteoglycans) with those of sPLA2-IIA. In addition, we also investigated the effect of a Western diet and lipopolysaccharide challenge on the aortic expression of these enzymes in mouse models.

Methods And Results: Immunohistochemistry showed sPLA2-V in human and mouse lesions to be associated with smooth muscle cells and also surrounding foam cells in lipid core areas.