Eptifibatide and 7E3, but Not Tirofiban, Inhibit α v β 3 Integrin–Mediated Binding of Smooth Muscle Cells to Thrombospondin and Prothrombin

Abstract

To the Editor: The recent article in Circulation by Lele et al1 reports αvβ3 inhibitory activity of eptifibatide. Surprisingly, the authors contend that this is a novel observation. Lele et al1 demonstrate inhibition of αvβ3-mediated adhesion of human aortic smooth muscle cells (HASMCs) to thrombospondin (TSP) or prothrombin, human umbilical vein endothelial cell attachment to TSP or vitronectin, as well as the inhibition of TSP-induced proliferation of HASMCs mediated by αvβ3, with IC50 values of approximately 30 μmol/L in each assay. All of these data are consistent with the original publication on the αIIbβ3 antagonist, eptifibatide, by Scarborough et al.2 The authors reported that this agent is a highly selective integrin antagonist. They also showed that at higher concentrations, eptifibatide can …