ALPHA(V)BETA(3) INTEGRIN EXPRESSION IN NORMAL AND ATHEROSCLEROTIC ARTERY

Recent evidence suggests that alpha(v) beta(3) integrin is a critical molecule in several processes involved in atherosclerosis progression and in restenosis, eg, smooth muscle cell (SMC) migration and angiogen esis. While several ligands for this integrin are known to be present in atherosclerotic plaque, little is known about the presence of alpha (v) beta(3), integrin at this site. In the present study, we have exam ined alpha(v) beta(3) expression in normal and atherosclerotic arterie s. Thirty-six coronary artery segments from the recipient hearts of 24 patients undergoing heart transplantation were classified into two gr oups: nonatherosclerotic diffuse intimal thickening (DIT) and atherosc lerotic plaques. Serial frozen sections were examined immunohistochemi cally with four different monoclonal antibodies directed against human alpha(v) beta(3) complex or the beta(3) subunit and with cell markers for SMCs, macrophages, and endothelial cells. The endothelium along t he lumen of both DIT and plaque arteries showed high expression of alp ha(v) beta(3) The media of both DIT and plaque arteries showed less in tense but extensive expression of alpha(v) beta(3) Immunoprecipitation and reverse-transcribed polymerase chain reaction (RT-PCR) analyses p erformed on extracts from the aortic media confirmed the presence of a lpha(v) beta(3) in the media. Ln the intima of both DIT and plaque art eries, alpha,beta(3), expression generally colocalized with SMCs but r arely with macrophages. The microvessels in the adventitia as well as in the plaque showed prominent expression of alpha(v) beta(3), in cont rast to low expression in similar-sized microvessels of the skin. Thes e results suggest that alpha(v) beta(3) is present both in the normal artery and in sites of SMC accumulation and angiogenesis in atheroscle rotic plaques.