Native Atherosclerosis and Vein Graft Arterialization: Association with Increased Urokinase Receptor Expression In Vitro and In Vivo

SummaryInteraction of proteases with cell surface receptors may modulate cell adhesion, migration, invasion, and matrix degradation. Since the plasminogen activator system has been hypothesized to play a role in intimal thickening after various types of vascular injury, we first studied the expression of urokinase receptor (u-PAR) protein and mRNA by smooth muscle cells (SMC) grown in explant cultures from normal and diseased vessels. Using equilibrium binding studies with radiolabeled 125I-labeled single chain urokinase-type plasminogen activator (scu-PA), we determined that SMC cultured from atherosclerotic arteries expressed a higher maximal number of binding sites/cell (3.6 ± 0.4 × 105 sites/cell vs. 2.1 ± 0.3 × 105, ± SEM, p