Sunday, March 27, 2011

Russell's Viper Venom & Blood Clots

Daboia russelii. Photo Credit: 
Abhinav Chawla  
Fibrinolytic drugs are given after a heart attack to dissolve the blood clot blocking the coronary artery, and they have been used experimentally in stroke and in massive pulmonary embolisms. Enzymes that are fibrinolytic have been found in the venoms of several snakes, such as the Malaysian Pit Viper, Calloselasma rhodostoma; the lancehead, Bothrops atrox; the Lebentine Viper, Vipera lebetina; the Eastern Diamondback Rattlesnake, Crotalus adamanteus; the Copperhead, Agkistrodon contortrix; and Russell's Viper, Daboia russelii.  The ability of the fibrinolyrtic enzyme from the Lebetine Viper has been studied for the removal of blood clots using rats and fibrinolytic enzymes from the Malaysian Pit Viper, C. rhodostoma,  and from the lancehead, B. atrox were used in  patients with deep vein thrombosis and ischemic stroke under controlled condition. Recently, recombinant fibrinolytic enzymes derived from snake venom were used in clinical trials. Venom from eastern Indian Russell Vipers (Daboia russelii russelii) has two hemorrhagins as well as VRR-73 that shows fibrinolytic and esterolytic activities that are independent of hemorrhagic activity. Gargi Maity and colleagues have now demonstrated that Russel Viper venom can be denatured at a temperature of 100 C so that it looses its hemorrahgic activity, but it does not alter its fibrinolytic ability. Thus, the fibrinolytic activity of VRR-73 has the potential for development as anticoagulant for therapeutic use once the hemorrhagic activity of the venom has been removed. Viper venoms are rich source of active proteins and peptides that affect hemostatic system and a likely source of more molecules that can have a direct, positive impact on human health.

Citation
Maity, G., et al., 2011. Thermal detoxification of the venom from Daboia russelli russelli of Eastern India with restoration of fibrinolytic activity, Toxicon (2011), doi:10.1016/j.toxicon.2011.02.008.

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