DOI: 10.1097/mbc.0000000000001453 ISSN: 0957-5235

Exploring the ex vivo effects of Naja mossambica snake venom on the coagulation, ultrastructure and viscoelastic properties of human blood

Courtney Paige Hill, Christie Megaw, Johan Potgieter, Morné Strydom, Janette Bester
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Cytotoxic coagulopathy can become a significant consequence of snakebite envenomation by certain species of Elapidae, such as the Naja mossambica ( N. mossambica ). The venom of this snake is composed of various hemotoxins that may disrupt hemostasis. There is limited investigation on the use of the 20-min whole blood clotting test (20-WBCT) to confirm coagulopathy in elapid envenomation.

Objective

The study explored the ex vivo effects of N. mossambica venom on blood morphology and coagulation.

Methods

Human blood was exposed ex vivo to 0.15 ng/μl N. mossambica venom. The 20-WBCT and standard laboratory coagulation assays; prothrombin time, activated partial thromboplastin time, thrombin time and fibrinogen levels were measured to analyze coagulation. Thromboelastography (TEG) was used to evaluate the viscoelastic properties of whole blood. Additionally, scanning electron microscopy (SEM) was performed to analyze red blood cell (RBC) morphology and clot structure.

Results

The 20-WBCT revealed a significantly longer clot formation time of venom-exposed samples; however, recorded results were within the accepted reference interval. Venom-exposed samples also showed decreased clot strength and stability. Morphological studies of venom-exposed samples revealed abnormal RBCs with extensive spicules on cell membranes. Furthermore, moderate fibrin fusion was visible in the fibrin network of exposed samples. Lastly, TEG was able to indicate changes in coagulation parameters where the others did not.

Conclusion

N. mossambica venom interferes with hemostasis and contributes to RBC membrane instability. The study provides comparisons between laboratory-based and point-of-care coagulation analysis when exposed to N. mossambica venom. Additionally, it demonstrates the valuable insight TEG provides as a point-of-care test in snakebite management.

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