Thrombin-induced adhesion

Protein C exerts an antithrombotic effect by inhibiting Factors Va and Villa. In vitro data indicate that it has indirect prohbri-nolytic activity through its abhity to inhibit plasminogen activator inhibitor-1 (PAI-1) and to hmit production of activated throm-bin-activatable-hbrinolysis inhibitor. In vitro data also indicate that Activated Protein C may exert an anti-inflammatory effect by inhibiting human tumor necrosis factor production by monocytes, by blocking leukocyte adhesion to selectins, and by hmiting thrombin-induced inflammatory responses within the microvascular endothehum. 

Venturini CM, Dd Vecdiio PJ, Kaplan JE (1989) Thrombin-induced platelet adhesion to endothdium is modified by endothdial derived rdaxing factor (EDRF). Biochem Biophys Res Common 159 349-354. 

Williams, J. C., Forster, L. A., Tull, S. P., Wong, M., Bevan, R. J., and Ferns, G. A. (1997) Dietary vitamin E supplementation inhibits thrombin-induced platelet aggregation, but not monocyte adhesiveness, in patients with hypercholesterolaemia. Int J Exp Pathol 78,259-66. 

Cyclo(Met-Tyr) and cyclo(Met-Trp) produced a marked inhibitory effect toward platelet adhesion induced by both ADP and thrombin. A moderate cytotoxic effect was displayed by cyclo(Met-Trp) against HeLa (55.85% inhibition), HT-29 (39.80% inhibition), and MCF-7 cancer cells (54.96% inhibition) whereas... 

The intetaction of proteolytically-active a-tfarombin with platelets and other cells of the vasculature, such as endothelial cells and smooth muscle cells, plays a major role in both normal hemostasis and atherosclerosis. Despite extensive studies in numerous laboratories extending back over thirty years, major questions regarding the mechanism of these interactions remain uruesolved. Furthermore, since dirombin can also induce chemotaxis and adhesion of inflammatory cells, and fibroblast mitogenesis, the importance of elucidating the nature of its receptor, or receptors, extends r beyond its role in platelet activation. However, this review will be restricted mainly to considerations of thrombin receptors in human platelets. 

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