Micro Clots and Long COVID: New Insights from Recent Study

Understanding Long COVID

A recent study conducted by a research team led by Professor Resia Pretorius at Stellenbosch University in South Africa is the first to indicate that COVID-19 can result in the formation of micro clots even after the infection has resolved. These blood clots may be linked to ongoing symptoms associated with Long COVID, such as fatigue and muscle weakness.

Individuals experiencing Long COVID often seem to have recovered from the acute phase of COVID-19 but continue to suffer from various persistent symptoms. These symptoms include fatigue, shortness of breath, muscle fatigue, anxiety, depression, and sleep disturbances. Such effects can linger for up to six months following the initial infection.

Defining Micro Clots and Their Risks

Blood clots are created through the aggregation of proteins known as clotting factors and platelets. These clots can obstruct blood flow in small blood vessels, or capillaries, which play a crucial role in gas exchange—transporting oxygen and carbon dioxide throughout the body. When a blood clot blocks this exchange, it can lead to insufficient oxygen delivery to tissues, resulting in fatigue and low energy levels.

In healthy individuals, blood clots are typically resolved through a natural process called fibrinolysis. While clotting is necessary for preventing excessive blood loss and aiding in the repair of blood vessels, micro clots are smaller clots that may remain in the bloodstream after a COVID-19 infection. The research indicates that these micro clots could be a significant factor contributing to the energy deficiency observed in Long COVID patients.

Micro Clots and Their Resistance to Breakdown

The research team analyzed blood samples from 13 healthy individuals, 11 patients with Long COVID, and 15 patients with active COVID-19. Findings revealed that both groups—those currently infected and those with Long COVID—had micro clots that were resistant to fibrinolysis. The study employed an enzyme treatment called trypsinization to break down these micro clots, but they only began to decompose after a second application.

Moreover, the presence of inflammatory factors such as alpha(2)-antiplasmin and serum amyloid A was significantly elevated in the micro clots of Long COVID patients compared to healthy volunteers. Alpha(2)-antiplasmin inhibits the breakdown of clots, while serum amyloid A promotes clot formation by attracting platelets.

Potential Treatments for Micro Clots

The researchers propose that individuals suffering from Long COVID may benefit from prolonged anti-clotting therapy after their COVID-19 infection. This treatment aims to mitigate complications arising from these clots. Further research is underway with a larger sample size to validate these findings and support future clinical applications.

References

1. Pretorius, E. et al. (2021). Persistent clotting protein pathology in Long COVID/Post-Acute Sequelae of COVID-19 (PASC) is accompanied by increased levels of antiplasmin. Cardiovascular Diabetology; 20(172). Doi: 10.1186/s12933-021-01359-7.

2. Page, M.J. et al. (2019). Serum amyloid A binds to fibrin(ogen), promoting fibrin amyloid formation. Scientific Reports; 9(3102). Doi: 10.1038/s41598-019-39056-x.

3. Basson, Wiida. (2021). First evidence of inflammatory micro clots in blood of individuals suffering from Long COVID. EurekAlert! Accessed Oct. 8 2021. Retrieved from https://www.eurekalert.org/news-releases/930392.

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