Expression of cyclo-oxygenase-2 in human atherosclerotic carotid arteries

Objectives: the preventive effect of acetylsalicylic acid in cardiovascular disease may be due to inhibition of platelet aggregation mediated by COX-1, but may in addition be due to anti-inflammatory effects by inhibition of COX-2. The objective of this study was to analyse the expression of COX-1 and COX-2 in atherosclerotic and healthy vascular walls. Design: the expression COX-1 and COX-2 was analysed in biopsies from human atherosclerotic carotid arteries and from healthy mammary arteries and saphenous veins. Materials: vascular biopsies were obtained from patients undergoing carotid endoarterectomy or coronary bypass surgery. Methods: RT-PCR was used for mRNA analysis and for localization of proteins we used immunohistochemistry. Results: COX-2 tons found in atherosclerotic plaques: in macrophages, in some smooth muscle cells and in endothelial cells of small vessels in the lesions. In non-atherosclerotic blood vessels, COX-2 was detected in the endothelium of the vasa vasorum in the adventitia. COX-1 was found in the endothelium in healthy and in atherosclerotic vessels. Conclusions: the expression of COX-2 by inflammatory and vascular cells in atherosclerotic arteries suggests that products of this enzyme may be important in the pathogenesis of atherosclerosis.