Lifesaving Venom

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People have evolved to fear snakes out of necessity. One bite from a venomous snake can be fatal! So it is ironic that a number of remarkable drugs come from poisonous snakes and other deadly creatures. Researchers increasingly prize this group of animals, believing their venom can treat major disorders ranging from high blood pressure, to heart disease, and cancer.

So, why is venom made into lifesaving drugs? Take the Brazilian pit viper - it incapacitates its victims by causing their blood pressure to plummet. But when molecules in the venom are developed into therapeutic drugs such as ACE inhibitors, they lower high blood pressure by decreasing chemicals that tighten blood vessels so that blood flows more smoothly.

Another drug called tirofiban comes from the saw-scaled viper, whose venom thins the blood and causes victims to bleed out. As a drug, it's an anticoagulant that clears blood clots in people with a minor or impending heart attack.

Another snake venom, from the Malayan pit viper, also thins blood. However, its venom possesses a protein that may dissolve blood clots in stroke victims up to six hours after the first symptoms appear. That would improve on the three hour window of existing drugs, and save a lot more lives.

Scientists are venturing beyond snake venom. The deathstalker scorpion is a bright yellow spider whose bites can be fatal. Yet, its venom contains chlorotoxin which just happens to attach to cancer cells by binding strongly to a cancer specific protein. By fluorescently labeling chlorotoxin, surgeons can identify and remove cancer tissue. Chlorotoxin can also be used to kill cancer cells by delivering radioactivity directly to tumors.

While this is all great news, scientists are concerned negative environmental impacts on the habitat of exotic species will limit their work. Ultimately, that's fewer life saving drugs available to all of us.

More Information

How a pit viper saved millions of lives: Snakes as drug factories
Discover Magazine — "Snake venom is a blend of molecules, many of which are exquisitely adapted for wreaking havoc. Some are enzymes that slice muscles apart. Some grab onto proteins that normally form clots, so that a snake's victim can't stop bleeding. Many snake venoms attack the nervous system with molecular precision that is so good that neuroscientists have snakes to thank for some of their biggest discoveries..."

Making medicines from poisonous snakes
Animals in Research — "Within minutes, the bites of rattlesnakes, cobras, pit vipers, or other poisonous snakes may cause you to have severe burning pain and swelling at the bite site. This local reaction may quickly be followed by a severe drop in blood pressure or paralysis that causes you to collapse, and have extensive bleeding everywhere in your body, with major bruising spreading from the bite, and blood escaping from your nose and mouth. Without treatment, you may die..."

From viper's venom to drug design: Treating hypertension
A relatively layman-friendly article published in the Journal of the Federation of American Societies for Experimental Biology.