On average, snakes bite 1.8 million people worldwide each year, and 138,000 of those are fatal. Researchers have now found a new treatment for at least cobra bites — a common blood thinner called heparinoids.
If a venomous snake bites you, getting antivenom as quickly as possible is crucial. Unfortunately, not all venoms — including venom from several cobra species — have effective antivenom. Cobras may not be the deadliest snakes in the world, but their venom can still cause serious tissue damage.
Most antivenoms are specific to either one or a few species of snake. They are expensive, have a limited shelf life, need refrigeration, and must be administered in a hospital. However, most snakebites occur in remote areas, where medical treatment is not easily accessible. Also, though antivenoms save lives, they do not limit the tissue damage around the site of the bite. The necrosis is often so severe that it leads to amputations.
Decoying away the venom
Scientists from the UK, Australia, Canada, and Costa Rica set out to find more treatment options for snakebites. Typically, research focuses only on a few of the quickest-acting and deadliest venoms.
“It’s a neglected area….It seems like if it’s not immediately fatal, it’s not the main focus,” Shirin Ahmadi, a specialist in skin cell death who did not participate in the study, told Science.org.
The team decided to start with cobras and picked one whose venom causes tissue damage. Using venom from African spitting cobras and CRISPR gene-editing technology, they identified the genes affected by cobra venom and which trigger necrosis. Those genes involved in producing heparan sulfate — common sugars in cell membranes — seem to be central to the tissue damage. Toxins from the venom bind to these sugars, damaging the cells and tissues.
When the research team saw this, they had a brain wave. If they could find a molecule similar to heparan sulfate, it might act as a decoy. This is where heparinoids and heparin come into play. When cells are flooded with blood thinners, the toxins bind to them instead of to the sugars in cell membranes. This stops the toxins from harming cells and necrosis from developing. Lab tests confirmed this worked in both human cells and in mice.
This is a huge leap forward in treating snakebites. As these drugs are already approved and readily available, moving to clinical trials will be a speedy process. In the long term, scientists hope to create an epi-pen device that rural people at high risk of cobra bites can carry.
“Our discovery could drastically reduce the terrible injuries from necrosis caused by cobra bites,” co-author Greg Neely told The Independent. “It might also slow the venom, which could improve survival rates.”
