Relative expression of cyclo-oxygenase COX-1 and COX-2 in porcine endothelium subjected to chronic shear stress

Endothelial cells are enriched with cyclo-oxygenase (COX) which, together with prostacyclin synthase, catalyses the conversion of arachidonic acid to the anti-thrombotic hormone prostacyclin. Generally, COX-1 is expressed constitutively whilst COX-2 is induced at sites of inflammation. COX-1 predominates over COX-2 in endothelial cells cultured under static conditions. However, it is unclear which isoform predominates in endothelial cells cultured under shear stress, as is normally experienced by endothelial cells in vivo. Because experiments employing short bursts of shear stress can provide misleading results, since these can be perceived by cells as an inflammatory insult, we have studied COX-1 and COX-2 expression in cells cultured under shear stress for prolonged periods.