How COVID-19 could be crippled by an age-old blood thinner

Much of the effort to develop remedies and vaccines to fight COVID-19 has centered around the spike protein that the culprit virus, SARS-CoV-2, uses to invade healthy cells. Scientists at Rensselaer Polytechnic Institute believe they’ve found a way to block the spike protein’s ability to infect cells—and it involves a 78-year-old blood thinner.

The drug is heparin, which is widely used to treat and prevent blood clots. The RPI team discovered that SARS-CoV-2 binds tightly to heparin, making the drug a potential “decoy” that could serve as a way to neutralize the virus before it can infect healthy cells. They reported the finding (PDF) in the journal Antiviral Research.

The RPI researchers made the discovery by studying gene sequencing data for SARS-CoV-2 and recognizing certain characteristics of the spike protein they believed would make it likely to bind to heparin. They tested three variants of the drug, including a non-anticoagulant formulation, against the virus, using computational modeling to define how they bound to the pathogen.

By binding to SARS-CoV-2, the blood thinner traps the virus, “which can’t exist really sitting there, bound to the heparin. It’ll just degrade,” explained Jonathan Dordick, Ph.D., professor of chemical and biological engineering at RPI, in a video.

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Dordick’s team was already working on methods for trapping viruses when the COVID-19 pandemic started spreading. The researchers developed a viral trap technology that uses pieces of DNA to mimic the latching sites on human cells, and they published research showing promising early data in dengue, influenza A and Zika.

While looking for ways to translate the viral trap technology to COVID-19, Dordick teamed up with Robert Linhardt, Ph.D., professor of chemistry and chemical biology at RPI, who is well known for his creation of synthetic heparin.

Some blood thinners are already being used by physicians treating COVID-19. Demand for Bristol Myers Squibb's Eliquis skyrocketed earlier this year following reports that the drug could prevent strokes in seriously ill patients.

The RPI researchers are proposing that heparin be used as a stopgap measure against COVID-19 until a vaccine is found. The drug could be delivered in an inhaled form to people who have been exposed to COVID-19, they suggested.

“This approach could be used as an early intervention to reduce the infection among people who have tested positive, but aren't yet suffering symptoms,” said lead author Linhardt in a statement. “Ultimately, we want a vaccine, but there are many ways to combat a virus, and as we’ve seen with HIV, with the right combination of therapies, we can control the disease until a vaccine is found.”