Blood thinner may revolutionise cobra bite treatment in India

Researchers from the University of Sydney and the Liverpool School of Tropical Medicine have found that heparin, a well-known blood thinner, can also be used to counteract cobra venom. This means heparin could potentially serve as an antidote for cobra snakebites. This discovery could change how snakebites are treated in areas where cobra snakebites are a major health issue.

Professor Greg Neely from the University of Sydney, who co-authored the study, told Interesting Engineering media house (IE), that they already had FDA-approved heparinoid drugs—which are similar to heparin, a blood thinner, and help prevent blood clots, besides having other medical uses, such as reducing inflammation—at the dosage and delivery method they used. If they could prove this works on humans, it could be quickly available as a treatment.

Antivenom-Snake Bite Solution

In such countries as India, the standard treatment for snakebites involves administering ‘antivenom’. To create it, scientists first gather venom from the specific snake species. They then inject small, safe amounts of this venom—known as sub-lethal (not deadly) and sub-toxic (not harmful)—into animals like horses and sheep. These animals produce antibodies to combat the venom. The antibodies are then collected, purified, and stored in vials with preservatives for use.

Ability to Decrease Necrosis

Necrosis can occur in snakebite cases when the venom damages skin and tissue. This damage reduces blood flow, causing cells to die. As a result, the affected area may become discoloured and swollen, and cause pain. In severe cases, necrosis can lead to tissue loss and, if left untreated, can be life-threatening.

Neely emphasised the importance of their finding and said their discovery could significantly lessen the serious injuries from necrosis caused by cobra bites. It may also slow down the venom, which could help improve survival rates. The research team, including scientists from Australia, Canada, Costa Rica, and the UK, used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) gene-editing technology to find out which human genes cobra venom attacks to cause necrosis.

Scientists have discovered that heparin and similar drugs can block these targets, helping to stop necrosis from occurring. Their findings show that heparin can work as a ‘decoy’ antidote by binding to the venom’s toxins and neutralizing them.

Pathway to Human Trials

Ph.D student and lead author Tian Du highlighted the benefits of heparin, stating that it was affordable, widely available, and was listed as an ‘essential medicine’ by the World Health Organization (WHO). Once human trials are successful, it could be quickly introduced as an affordable, safe, and effective treatment for cobra bites.

Explaining the use of CRISPR in their research, Neely told IE that they used CRISPR to disable every gene in the human genome—the complete set of genetic material in humans—in a large group of cells. Then they added snake venom, which normally would kill all healthy human cells. The human genome, consisting of about 20,000 to 25,000 genes, includes all the DNA, which contains the instructions for building and maintaining the body.

The researchers sequenced the surviving cells to pinpoint the human genes that provide resistance. They found out that cobra venom attacks heparan and heparins. By using extra heparin, a common medicine, they injected it at the site of the snakebite. In mice, this method prevented nearly all local damage. Heparan and heparins are types of molecules found in the body. They are involved in various biological processes, including blood clotting and cell growth. In the context of the study, these molecules are the targets of cobra venom, meaning the venom attacks them.

Transitioning from successful lab trials to human clinical trials requires a lot of funding. Neely further told IE that they needed to raise about $8 million to start a clinical trial, which could be difficult since cobra bites affect some of the poorest regions in the world. However, they hoped to attract interest from governments or charitable organizations to help cover the costs.

Low/Middle-Income Nations’ Challenges

Snakebites cause up to 138,000 deaths each year and around 400,000 people experience long-term effects. In such regions as India and Africa, cobras are responsible for many of these snakebite cases. WHO has made snakebite a priority in its efforts to address neglected tropical diseases and bring down the global incidence of snakebites by 50% by 2030. Professor Nicholas Casewell from the Liverpool School of Tropical Medicine and co-author of the study said snakebites were the most deadly among neglected tropical diseases and their impact was mostly felt in rural communities of low- and middle-income countries.

Current antivenoms are mostly ineffective for severe local venom effects, causing painful swelling, blisters, tissue damage, and long-term disabilities. The heparin-based antidote is a new type of treatment for cobra venom that focuses on preventing tissue damage at the bite site, unlike current antivenoms. Neely further explained that, while antivenoms could effectively counteract the widespread effects of cobra venom, they were not very good at stopping tissue damage right at the bite site.

The main challenge in low- and middle-income countries is getting money to fund clinical trials. If the trials are successful, the next challenge will be distributing the medicine to those in need. This, possibly, involves training healthcare workers in rural areas on how to inject heparin or a similar molecule, Neely explained to IE.

(The author of this article is a Defence, Aerospace & Political Analyst based in Bengaluru. He is also the Director of ADD Engineering Components, India, Pvt. Ltd, a subsidiary of ADD Engineering GmbH, Germany. You can reach him at: girishlinganna@gmail.com)