Blood thinner threatens to take the sting out of cobra’s deadly bite
22 Jul 2024
CRISPR gene editing technology has enabled scientists at the University of Sydney and Liverpool School of Tropical Medicine to identify a popular blood thinner as a potential cheaper antidote to cobra venom.
The venom injected by species from the genus of poisonous snakes can not only cause death but alternatively necrosis, leading to amputation for many survivors.
Currently-used antidotes are costly and do not appear to combat the death of body tissue and cells. However, the researchers, working with colleagues in Canada and Costa Rica, identified that the common blood thinner heparin could be repurposed to tackle necrosis also.
“Our discovery could drastically reduce the terrible injuries from necrosis caused by cobra bites – and it might also slow the venom, which could improve survival rates,” said professor Greg Neely of Sydney’s Charles Perkins Centre and Faculty of Science.
While the several species of cobra do not rank as the most poisonous snakes worldwide, the Indian Cobra ranks as one of the so-called ‘Big Four’ snake species collectively responsible for causing the most human deaths and injuries in South Asia. This is attributed in part to the size of their population, aggression, speed and proximity to humans.
It has been estimated that the number of serious injuries including amputations from necrosis from Indian Cobra bites could be between six and 10 times the actual deaths attributed.
Discussing the research published in Science Translational Medicine, the researchers explained CRISPR was employed to pinpoint the human genes the venom required to cause necrosis. One venom target is the enzymes needed to produce heparan and related molecule heparin; heparan occurring on the cell surface and heparin being released during an immune response.
Their similar structure allows the venom to bind to both, prompting the team to make a heparinoid drug antidote that can stop necrosis in human cells and mice.
Flooding the wound site with ‘decoy’ heparin sulfate or related heparinoid molecules permitted the antidote to bind to and neutralise the toxins within the venom that cause tissue damage.
Sydney PhD and lead author Tian Du pointed out that heparin was inexpensive, ubiquitous and a World Health Organisation-listed Essential Medicine that might quickly become a cheap, safe and effective drug for treating cobra bites.
Head of the LSTM Centre for Snakebite Research & Interventions and joint corresponding author professor Nicholas Casewell said:
“Our findings are exciting because current antivenoms are largely ineffective against severe local envenoming, which involves painful progressive swelling, blistering and/or tissue necrosis around the bite site. This can lead to loss of limb function, amputation and lifelong disability.”
He said the research could help boost the WHO goal of halving the global burden of snakebite by 2030.
Professor Neely said: “That target is just five years away now. We hope that the new cobra antidote we found can assist in the global fight to reduce death and injury from snakebite in some of the world’s poorest communities.”
Photo: Chinese cobra milked for venom (Neely/Casewell)
