Researchers uncover evidence of inflammatory micro clots in long-COVID patients

New research indicates that an overload of various inflammatory molecules, “trapped” inside insoluble microscopic blood clots or micro clots, might be the cause of some of the lingering novel coronavirus (COVID-19) symptoms experienced by individuals with long COVID.

Alpha(2)-antiplasmin is a molecule that prevents the breakdown of blood clots, while fibrinogen is the main clotting protein. Under normal conditions the body’s plasmin-antiplasmin system maintains a fine balance between blood clotting and fibrinolysis. With high levels of alpha(2)-antiplasmin in the blood of COVID-19 patients and individuals suffering from long COVID, the body’s ability to break down the clots are significantly inhibited.

The discovery was made by Resia Pretorius, PhD, a researcher in the Department of Physiological Science at Stellenbosch University (SU), when she started looking at micro clots and their molecular content in blood samples from individuals with long COVID. The findings are published in the journal Cardiovascular Diabetology.

The insolubility of the micro clots became apparent when Maré Vlok, PhD, a senior analyst in the Mass Spectrometry Unit at SU’s Central Analytical Facilities, noted that the blood plasma samples from individuals with acute COVID-19 and long COVID continued to deposit insoluble pellets at the bottom of the tubes after dilution, a process called trypsinization.

The researchers are the first to have reported on finding micro clots in the blood samples from individuals with long COVID, using fluorescence microscopy and proteomics analysis, thereby solving yet another puzzle associated with the disease.

Further research is recommended into a regime of therapies to support clotting and fibrinolytic system function in individuals with lingering long COVID symptoms, the researchers said.

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