Human carotid artery smooth muscle cells rarely express alpha v beta 3 integrin at sites of recent plaque rupture

Fibrin(ogen) is the major matrix ligand for beta 3 integrins. If alpha v be ta 3 is the major receptor for fibrin(ogen) on intimal smooth muscle cells, we might expect to see this integrin associated with fibrin(ogen), Eighty four specimens obtained from endarterectomies of 14 patients were studied. Fibrin was frequently observed in carotid intima even at the non-atheroscle rotic areas. As for beta 1 and beta 3 integrins, beta 1 was predominant in intima. The alpha v beta 3 integrin expression was less frequent than alpha 5 beta 1, another receptor for fibrin(ogen), in diffuse intimal thickening , fibrous cap and advanced plaques. Furthermore, alpha v beta 3 was general ly negative on smooth muscle cells in recent plaque ruptures. In conclusion , we suggest more attention should be paid on abundant fibrin matrix in int ima. Histologically, the alpha 5 beta 1 integrin rather than the alpha v be ta 3 is the major receptor for fibrin in intimal smooth muscle cells.