LOCALIZATION OF VITRONECTIN IN THE NORMAL AND ATHEROSCLEROTIC HUMAN VESSEL WALL

Vitronectin (Vn) regulates proteolytic enzyme systems, as well as cell migration and tissue remodelling. These processes have been implicate d in the pathogenesis of atherosclerosis. In this study, the distribut ion of Vn antigen in apparently normal and atherosclerotic human blood Vessels was evaluated. Normal and diseased vessels showed Vn immunost aining in the lamina elastica interna and externa, and in strand-like structures in the adventitia. In most of these instances, the Vn antig en appeared to be located in the proximity of elastin. In pulmonary ar teries, Vn staining was additionally detected in the media. The intima was devoid of Vn antigen in all vessels studied. In general, there wa s increased deposition of Vn antigen in the atherosclerotic arteries. In particular, strong Vn staining was apparent in amorphous material a djacent to cholesterol clefts and in acellular fibrous tissue, in plaq ues present in the carotic artery and aorta. Collagen layers and fresh fibrin depositions were devoid of Vn antigen. In spite of the abundan ce of Vn immunostaining throughout the normal and diseased vessel wall , the Vn transcript was not detectably by in situ hybridization. These results indicate that Vn is a constituent of the normal vessel wall a nd raise the possibility that increased local deposition of Vn may be related to the development of atherosclerotic vascular disease.