Thrombin generation test for evaluating hemostatic effects of Brazilian snake venoms

Snake venoms as well as their components have been tested worldwide to find new molecules for prophylaxis and treatment of several pathologies or even for diagnostic purposes. It is widely known that snake venoms contain enzymes and non-enzymatic proteins that interfere with hemostasis leading to hemorrhage or even thrombosis. The treatment of snake envenoming and the development of new drugs. The thrombin generation test (TGT) is a highly sensitive tool for investigation of hemostatic changes, overlapping with existing coagulometric techniques. The aim of this study was to use TGT to evaluate in vitro hemostatic changes caused by venom of Brazilian snakes B. jararacussu, B. alternatus, B. moojeni and C. durissus terrificus in a normal pool of platelet-poor plasma, comparing results to those obtained by the classical coagulation assays, at the same concentrations of venom. B. moojeni venom showed to be more hypercoagulable, with a greater ability to activate coagulation, evidenced by increased values of Endogenous Thrombin Potential (ETP), even in the reactions in which the triggering reagent (tissue factor) was not added. On the other hand, the lowest ETP values were observed in plasma incubated with C. durissus terrificus venom. As a new finding of great importance, all venoms at the same concentrations assessed by TGT did not promote changes in a pool of platelet-poor plasma by classic coagulometric assays, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT), whose results were within the reference range. Thus, TGT showed to be more sensitive than the coagulometric assays to evaluate the hemostatic effect of venom components in vitro. Our preliminary results indicate a potential role for TGT in improving the laboratory investigation of hemostatic changes due to snakebite. In addition, elucidation of hemostatic changes induced by different Brazilian snake venoms related to hypocoagulability or hypercoagulability represents an important approach to improving the treatment of snake envenoming and the development of new drugs.