Snake venom could be the next miracle drug

Canadian and French scientists say they may have found an unlikely treatment for the scourge of cystic fibrosis: a protein extracted from the venom of certain rattlesnakes.

Early lab and animal experiments suggest the snake poison can counteract the chief genetic mutation linked to the disease, a new study reveals.

But it turns out to be just the latest development in a little-known branch of biomedical science that is transforming some of the most lethal and feared of animals into potential healers.

Researchers in Canada and elsewhere have tested the “rich” trove of chemicals in various serpent venom as possible therapies for heart failure, heart attacks, breast cancer, leukemia, bacterial infection and even severe pain.

If snake oil was once synonymous with quack medicine, science could make snake toxin a source of legitimate hope for patients.

“Venom has an amazing amount and variety of toxins, and their effect is really mind-boggling, how many things they can be used for,” said professor Gergely Lukacs, a McGill University biochemist who was part of the cystic fibrosis study. “Nature, it has unlimited potential to generate these tricky molecules.”

A leading Toronto-based scientist, meanwhile, is involved in developing a promising new drug for treating the blood clots that can lead to heart attacks and strokes, with the help of snakes.

Anfibatide is based on a protein purified from the venom of the southeast Asian viper, a nasty specimen nicknamed the “hundred pacer” for the distance that bite victims reach before collapsing.

Results of lab and mice tests published by Dr. Heyu Ni of St. Michael’s Hospital caused a stir two years ago, suggesting the drug was effective at curbing the clumping together of blood platelets — and thus at breaking up clots — seemingly without the increased risk of bleeding that comes with current blood thinners.

Now he is analyzing data from a just-completed phase-two trial involving patients in China at risk of heart attack.

“We do not fully understand some conditions,” Ni said in an interview Friday. “(But) we can learn from these animals, use their products to treat our own problems.”

Much of the research on snake poison is at a relatively early stage — laboratory or animal experiments — though another venom-derived clot-busting drug, Integrilin, is already on the market. And the widely used ACE-inhibitor hypertension pills were inspired by the poison of Brazilian pit vipers — whose victims drop almost instantly from plunging blood pressure.

Scientists have found viper toxins to be a surprisingly complex substance.

Venom was actually a key milestone in the evolution of snakes, which previously could subdue prey only “mechanically” — that is, by squeezing, notes Spanish biologist Juan Calvete in a 2013 paper. New, “advanced” serpents had poisons with a blend of ingredients able to immobilize, paralyze, kill and digest their would-be meals, he writes.

That venom is a “rich source of natural, multifunctional proteins,” says the cystic fibrosis (CF) paper just published by Lukacs and a team headed by biochemist Grazyna Faure-Kuzminska of Paris’s Institut Pasteur.

Discovering that one of those proteins could be useful in fighting CF is significant. Treatment of the disease has improved — extending patients’ average life expectancy to 50 years — but no drug effectively combats the underlying causes.

The new research suggests the protein CB purified from the South American rattlesnake has a “new and unexpected” ability to both correct the genetic defect behind cystic fibrosis and spur proper functioning of the gene.

Its effect in humans may turn out to be minimal, but the venom experiments revealed a new pathway for targeting the condition’s genetic origin that seems promising, said Lukacs.

In a 2013 article, pharmacologist Chris Bladen of the University of Calgary hailed a very different role for reptile toxin: treating pain with venom from the black Mamba — sometimes called the world’s most-lethal snake.

Morphine in its various natural and synthetic forms is the “gold standard” of pain therapy, notes Bladen, but its potential to cause addiction and overdose has become tragically clear in Canada recently.

A French animal study suggested two peptides from Mamba poison — which the researchers call Mambalgins — curb pain effectively but in a different way, avoiding opioid-type side effects, he says.

“Why these molecules have evolved in the venom of one of the deadliest snakes on Earth is unclear,” wrote Bladen. “It’s possible that Mambalgins (together with other ingredients in the poison) … help prevent prey from escaping.”

Among a number of findings related to cancer, a preliminary study published earlier this year suggested chemicals in the blunt-nosed viper’s venom curbed growth of colon-tumour cells.

And amid growing anxiety about antibiotic-resistant infections, another group reported evidence last year that proteins in the poison of Russell’s vipers could be a new type of bacteria killer.

It was a rare bit of good PR for the species. The dreaded viper is one of the main culprits in India’s vast snakebite problem, estimated to take 46,000 lives every year.