Scientists from the University of Sydney and the Liverpool School of Tropical Medicine have made a remarkable discovery by repurposing heparin, a commonly used blood thinner, as an inexpensive antidote to cobra venom.
Cobras kill thousands of people each year around the world, and many more may be seriously disfigured by the death of body tissues and cells (necrosis) caused by the venom.
Current treatment is expensive antivenoms, which do not effectively treat the necrosis of the flesh at the site of the bite.
Using CRISPR gene-editing technology to identify ways to block cobra venom, scientists have successfully repurposed heparin and related drugs to stop the necrosis caused by cobra bites.
"Our discovery could significantly reduce the horrific injuries caused by cobra bites, and could also slow down the release of the venom, which could improve survival rates," said Professor Greg Neely, author of the new study from the Charles Perkins Centre and the University of Sydney's Faculty of Science.
“Heparin is inexpensive, widely available and is a World Health Organization-listed essential drug,” said lead author Tian Du, from the University of Sydney. “After successful human trials, it could be rolled out relatively quickly as a cheap, safe and effective treatment for cobra bites.”
The research team used CRISPR technology to find the human genes that the cobra venom needs to cause the deadly necrosis of the flesh around the bite.
Scientists have discovered that one of the toxin's desired targets is the enzymes needed to produce the related molecules heparan and heparin, which are produced by many human and animal cells.
Heparan is found on the cell surface, and heparin is released during an immune response. Their similar structure suggests that the toxin can bind to both, which helped the team create an antidote that could stop the necrosis of human and animal cells.
Unlike current cobra antivenoms, heparinoid drugs act as a "trap" antidote by flooding the bite site with "decoy" heparin sulfate or heparinoid molecules, where the antidote can neutralize the venom.
“Our findings are exciting because current antivenoms are largely ineffective against severe local envenoming,” said co-author Professor Nicholas Casewell, head of the research centre at the Liverpool School of Tropical Medicine.
The World Health Organization has identified snakebites as a priority in its programme to tackle neglected tropical diseases, and has announced an ambitious goal of halving the global burden of snakebites by 2030.
The study was published in the journal Science Translational Medicine.