Open AccessEffects of Lopap on Human Endothelial Cells and Platelets
Author(s) -
A.M. Chudzinski-Tavassi,
Mirta Schattner,
Márcio Fritzen,
Rául Pozner,
Cleyson Valença Reis,
Dayse Maria Lourenço,
M.A. Lazzari
Publication year - 2001
Publication title -
pathophysiology of haemostasis and thrombosis
Language(s) - English
Resource type - Journals
eISSN - 1424-8840
pISSN - 1424-8832
DOI - 10.1159/000048071
Subject(s) - prothrombinase , platelet , thrombin , in vivo , coagulation , immunology , antithrombin , activator (genetics) , platelet activation , chemistry , medicine , endocrinology , biology , microbiology and biotechnology , heparin , receptor
Severe consumption coagulopathy has been detected in rats after Lopap (a prothrombin activator from Lonomia obliqua caterpillar bristles) infusion and in humans after accidental contact with L. obliqua bristles. However, platelet count and antithrombin (AT) levels were only modestly affected, suggesting that a different form of blood coagulation activation may be involved in this hemorrhagic syndrome. Here we describe that Lopap had no effect on aggregation of washed human platelets induced by several agonists, suggesting that it might not impair platelet function in vivo. AT was able to inhibit the amidolytic activity of thrombin generated by incubation of Lopap with prothrombin in a purified system, which may be different from that generated by the prothrombinase complex in vivo. The surface expression of both ICAM-1 and E-selectin but not of VCAM-1 was upregulated by Lopap in cultured HUVEC, suggesting that it may behave differently from other mediators, such as thrombin and tumor necrosis factor-alpha.