How and why some Covid-19 patients can develop life-threatening blood clots?

The study could lead to targeted therapies that prevent this from happening.


In a past study, it was found that blood clotting is a significant cause of death in COVID-19 patients. However, the reason behind this remains unclear.

To understand the association between blood clots and COVID-19 and why the clotting happens, scientists from RCSI University of Medicine and Health Sciences analyzed blood samples taken from patients with Covid-19 in the Beaumont Hospital Intensive Care Unit in Dublin.

Blood contains many proteins that help the blood clot when needed. One of these proteins is called von Willebrand factor (VWF). The protein helps blood to clot.

On the other hand, the ADAMTS13 enzyme processes a large protein called the von Willebrand factor. The ADAMTS13 enzyme cuts VWF into smaller pieces to regulate its interaction with platelets. By processing VWF in this way, the enzyme prevents it from triggering blood clots in normal circulation.

Scientists found that both VWF and ADAMTS13 are severely disrupted in patients with severe Covid-19.

In comparison with control groups, COVID-19 patients had higher levels of the pro-clotting VWF molecules and lower levels of the anti-clotting ADAMTS13. Also, some other changes in proteins caused the reduction of ADAMTS13.

Dr. Jamie O’Sullivan, the study’s corresponding author and research lecturer within the Irish Centre for Vascular Biology at RCSI, said“Our research helps provide insights into the mechanisms that cause severe blood clots in patients with Covid-19, which is critical to developing more effective treatments.”

“While more research is needed to determine whether targets aimed at correcting the levels of ADAMTS13 and VWF may be a successful therapeutic intervention, it is important that we continue to develop therapies for patients with Covid-19. Covid-19 vaccines will continue to be unavailable to many people throughout the world, and we must provide effective treatments to them and those with breakthrough infections.”

Journal Reference:
  1. Sorcha E. Ward et al. ADAMTS13 regulation of VWF multimer distribution in severe COVID-19. DOI: 10.1111/jth.15409
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