This could be the cause of some of the long-term symptoms experienced by people with Long COVID.
New findings, peer-reviewed and published in the journal Cardiovascular Diabetology, suggest that an excess of various inflammatory molecules, “trapped” inside insoluble small blood clots, could be the main cause of some of the long term symptoms experienced by people with Long COVID.
Prof Resia Pretorius, a researcher in the Department of Physiological Science at Stellenbosch University (SU), made this surprising discovery when she began looking at micro clots and their molecular makeup in blood samples from people with Long COVID.
“We found high levels of various inflammatory molecules trapped in micro clots present in the blood of individuals with Long COVID. Some of the trapped molecules contain clotting proteins such as fibrinogen, as well as alpha(2)-antiplasmin,” explained Prof Pretorius.
Alpha(2)-antiplasmin is a molecule that prevents blood clot breakup, whereas fibrinogen is the key clotting protein. The body’s plasmin-antiplasmin system normally keeps a delicate balance between blood clotting (the process by which blood thickens and coagulates to minimize blood loss after an injury) and fibrinolysis (the process of breaking down the fibrin in the coagulated blood to prevent blood clots from forming).
The body’s capacity to break down clots is greatly hampered by high amounts of alpha(2)-antiplasmin in the blood of COVID-19 patients and persons suffering from Long COVID.
Dr. Maré Vlok, a senior analyst in the Mass Spectrometry Unit at SU’s Central Analytical Facilities, noticed that blood plasma samples from persons with acute COVID and Long COVID continued to deposit insoluble pellets at the bottom of the tubes after dilution (a process called trypsinization).
He informed Prof Pretorius of his observation, and she looked into it further. They are now the first study group to describe the discovery of micro clots in blood samples from people with Long COVID using fluorescence microscopy and proteomics analysis, addressing yet another riddle linked with the disease.
“Of particular interest is the simultaneous presence of persistent anomalous micro clots and a pathological fibrinolytic system,” they wrote in their study.
This suggests that the plasmin and antiplasmin balance may be important in Long COVID diseases, and it adds to data that COVID-19, and now Long COVID, have major cardiovascular and coagulation pathologies.
More study on a regimen of medicines to improve clotting and fibrinolytic system activity in individuals with persistent Long COVID symptoms is required.
They now intend to conduct the same research on a larger sample of patients in collaboration with vascular physician Dr. Jaco Laubscher of Mediclinic Stellenbosch (a co-author on the article).
To date, they have gathered blood from one hundred Long COVID patients who took part in the Long COVID registry, which opened in May 2021, as well as 30 healthy people.
The research is supported by the Long COVID Research Charitable Trust, which was created with an initial grant from ENSafrica’s Mr. Koos Pretorius. This trust will be used to raise more funding for research into the causes and effective treatment of those suffering from Long COVID.
Reference: DOI: 10.1186/s12933-021-01359-7
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