Study finds common blood-thinning drug may prevent tissue damage and amputation in snake bites

When cobras attack, they use their fangs to inject a powerful venom into their victims, and patients bitten by the snake face a race against time to get to a hospital where doctors can administer an antibody-based treatment. Antitoxin.

But these antivenoms are expensive, and while they often save the victim's life, they are largely ineffective at preventing tissue death, or necrosis, around the snakebite. 400,000 people per year Snake bites can cause permanent disability, and in some cases the affected limb may have to be amputated.

Now, researchers have found a potential solution to this problem: a common blood-thinning drug, according to a new paper published last week in the journal Neurology. Science Translational MedicineThe international team describes the use of heparin and related compounds, a frequently prescribed, inexpensive blood-clotting inhibitor, to prevent the cobra venom from destroying tissue and cells.

“Cobra venom causes severe local tissue damage… similar to an injection of acid.” Brian Fryis a biologist and biochemist at the University of Queensland in Australia, who was not involved in the study. GuardianCharlotte Thau of the University of California, San Diego, added that the new findings are “really exciting”.

Snake bites Key Issues In some parts of the world, it causes between 81,000 and 138,000 deaths each year, especially in sub-Saharan Africa, South Asia, and Southeast Asia. explain The government has designated snakebite a “neglected tropical disease” and has set a goal of halving the number of deaths and permanent disabilities caused by snakebites by 2030.

But snake venom itself has long been a mystery: It's made up of many different compounds, so scientists haven't been able to pinpoint exactly which components cause necrosis in bite victims, the researchers wrote. ScienceTo solve this mystery, researchers turned to gene-editing tools. CRISPR–This is also Box jellyfish venom antidote 5 years ago.

New cobra venom antidote could save thousands of lives each year

The team studied how human cells responded to injections of venom from two African snake species: the red cobra (Nadja Perl) and the Black-necked Spitting Cobra (Nadja BlackneckThe researchers found that toxins in the venom appear to bind to heparan sulfate and heparin, molecules with similar structures that are produced by human cells.

So the researchers used CRISPR to remove the genes responsible for making heparan and heparin, and sure enough, when they injected the venom into the gene-edited cells, the cells became more resistant to the venom's effects.

Scientists suspected that injecting the blood-clotting inhibitor heparin and related heparinoids into human cells might induce a toxin to bind to the drug rather than harming the cells.

To test these findings, the researchers performed experiments in mice. Injecting the animals with a heparin-like substance at the same time as the venom reduced the size of the lesions in the animals. The drug, called tinzaparin, reduced the size of the wounds in the mice by 94 percent.

The method also blocked the effects of the venom of other cobras, including the Asian three species. However, the treatment did not work on all snake venoms, such as the viper, because the main compound that causes necrosis, the three-finger toxin, is not found in the venom of all snake species. Science.

One unanswered question is whether the antivenom would be as effective at preventing necrosis if given soon after, rather than after being taken to the hospital in an ambulance, and it's also unclear how effective blood-thinning drugs are long after the bite.

“An hour later, four hours later, or [the] “How long does it take to get from a remote area of ​​Tanzania to someone bitten by a cobra in 24 hours?” Jeff Isbister“These findings suggest that the effects of toxicology are not related to the current study, but rather to the current state of affairs,” said Dr. new scientistJames Woodford.

But the researchers say heparinoids are not a replacement for antitoxin, but rather a complementary treatment: Victims still need to be injected with antitoxin to ensure their survival. But heparinoids, which are stable at room temperature and can be administered with an auto-injector similar to an EpiPen, could provide a stopgap measure to slow the poison's progression until a patient can reach a hospital.

From here, the heparinoids will need to go through clinical trials and be approved for human use in snakebites, but because the drugs are already approved for other uses and available in pharmacies, the researchers expect the process to be relatively quick and easy.

“Heparin is inexpensive, ubiquitous and listed as an essential medicine by the World Health Organization,” say study co-authors. Tien YuNeuroscientist and geneticist at the University of Sydney, Australia statement“If human trials are successful, this could be a relatively quick way to develop a cheap, safe and effective drug for treating cobra bites.”