Poison? Potion? — Snake venom as heart attack treatment
Snakebites can be deadly, but their poisons could be a lifesaver.
This glossy green snake is an Eastern green mamba (Dendroaspis angusticeps), found throughout the eastern Africa. Don’t be fooled by its lack of flashy red stripes or other visual warnings: its bites are highly poisonous. While you would want to avoid venomous snakes like the green mamba out in the wild, they are a treasure trove for some medical researchers.
One example of the potential of snake toxins is their use in heart attack therapy.
Heart attacks are the single largest cause of deaths in the United States, with approximately one death every minute. Heart attacks commonly occur due to the plaque buildup inside the heart arteries, often resulting in blood clot formation and blockage of blood flow into the heart. The lack of oxygen reaching the heart cells kills them, a phenomenon called fibrosis. Consequently, damages on the heart tissue result in less pumping of the heart (heart failure) or even a termination of the action itself (heart attack).
So, how do the snake venoms act as both lethal and therapeutic agents? This sounds counter-intuitive.
Many snake toxicants target vital parts of our body, such as nervous system and circulatory system. For example, some venoms cause the victims to bleed to death. By tweaking the toxins, they can be used for preventing blood clots. And this is not a new concept: the medical potentials of some snakes have been sought after for decades. In the 1960’s, the venom of the Malayan pit viper was conceived as a therapeutic agent for clearing blood clots.
Let us return to our green, lethal friend, the Eastern green mamba. Recently, Mayo Clinic researchers developed a new drug, called cenderitide, using a part of the snake’s venom. The modified snake toxin was fused to a naturally occurring hormone that lines our blood vessels. Together, the venom-hormone hybrid improved the blood flow and the heart function, preventing heart muscle death. The new drug is currently under Phase II clinical trials for treating patients with acute heart failure. Although it would take some time before cenderitide can be approved for the market – if it makes it to there at all, as many potential drugs fail during drug development and trials –, Mayo Clinic doctors and researchers are keeping their hopes high. They believe that their “efforts to merge the best of science and the best of nature” represent “a therapeutic breakthrough in drug discovery.” It would be interesting to see the results of the current clinical trials.
Other venom-derived drugs on the market for preventing or treating minor heart attacks are available since 1998: eptifibatide (from rattelesnake venom) and tirofiban (African saw-scaled viper venom).
Snake venoms are also regarded for their potential to treat other disorders: high blood pressure, stroke (being also caused by blood clot formation, but in the brain), Alzheimer’s disease, and cancer.