Characterization of the coagulotoxic profile of venoms of Viperidae snakes with medical importance in Brazil

• Grant number: 20/07268-2
• Support type: Regular Research Grants
• Duration: October 01, 2021 - September 30, 2023
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal researcher: Karen de Morais Zani
• Grantee: Karen de Morais Zani
• Home Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Assoc. researchers: Anita Mitico Tanaka-Azevedo ; Aparecida Sadae Tanaka ; Benedito Carlos Prezoto ; Bryan Greig Fry ; Kathleen Fernandes Grego ; Sávio Stefanini Sant Anna

Abstract

Snakebite accidents are classified by the World Health Organization as a neglected tropical disease responsible for approximately 2.5 million cases of envenomation and 150,000 deaths per year, especially in rural regions of Africa, Asia, Latin America and Oceania. In Brazil, the Viperidae family represents the most important group of snakes for public health, as they are responsible for the majority of registered snakebite accidents. Among the effects resulting from these accidents, it is believed that hemostatic disturbances caused by the venoms of a wide variety of snake species play a central role in the pathophysiology of the envenomation and in the capture of prey. Snake venoms, especially those belonging to the Elapidae and Viperidae families, have several toxins that interact with the blood coagulation cascade and the fibrinolytic system. Since the 1980s, the most used way to evaluate the coagulant activity of snake venoms is through the determination of "Minimum Coagulant Dose" (MCD). However, a new approach to characterize the coagulotoxicity of snake venoms is being employed to characterize this aspect of envenomation in different snake species, assessing not only the clotting time as an end point, but also the speed of its formation and its resistance. It also evaluates the activity of venoms on specific components of the hemostatic system and their dependence on calcium and phospholipids. These parameters allow the characterization of inter- and intraspecific variations related to the coagulant (or anticoagulant) activity of snake venoms, even if subtle. The intraspecific variability of snake venoms associated with their functional diversity is particularly critical when considering their reactivity with antivenom. For this reason, understanding the inter- and intraspecific variations in venomous snakes and their action on human envenoming is essential for the production and efficient use of antivenoms. In view of the complexity of the envenomation caused by snake species belonging to the Viperidae family and the relevance of these species to public health, the development of a multifaceted study comparing the coagulotoxic profile of the venoms of these species and their neutralization by the antivenom produced is extremely important. Thus, this project proposes the characterization of the coagulotoxic profile of individual venoms of species of snakes belonging to the genera Bothrops, Crotalus and Lachesis, with high medical importance in different Brazilian regions. (AU)