Guest blog, written by Paul Chazot

Introduction

Several people continue to experience persistent cognitive issues even after recovering from the initial phase of COVID-19, including with what we know as brain fog, a cognitive difficulty that have left researchers searching for solutions.

Recent research from a group at the University of Oxford led by Dr. Max Taquet and his associates has proposed that blood clots may also underlie COVID-induced brain fog in the later stages of COVID-19 infection, so-called Long COVID, a condition thought to affect 3.1% of the population.

In this blog post, we will look at the possible benefits of light therapy in promoting healthy blood circulation and explore its potential role in preventing specific conditions that lead to clotting and associated risks.

The Blood Clot Connection

Dr. Taquet and his team examined blood tests from 1,837 COVID-19 hospital patients to look for potential biomarkers linked to potential cognitive problems. What they discovered was vital: patients who later developed cognitive problems, including brain fog, had high levels of two proteins at the time of COVID-19 infection. These two proteins, fibrinogen and D-dimer, are essential in blood clotting.

Dr Taquet said: “Both fibrinogen and D-dimer are involved in blood clotting, and so the results support the hypothesis that blood clots are a cause of post-COVID cognitive problems. Fibrinogen may be directly acting on the brain and its blood vessels, whereas D-dimer often reflects blood clots in the lungs and the problems in the brain might be due to lack of oxygen”

These findings support the hypothesis that blood clots could be a causative factor behind post-COVID cognitive problems.

Implications and Potential Solutions

There has been a worldwide effort to prevent venous thromboembolism (VTE) in COVID-19 patients (during hospitalization and after discharge), as well as to determine the best management of patients with both COVID-19 and VTE diagnoses, as a result of the growing body of evidence suggesting that COVID-19 may predispose thrombotic disease. The necessity for non-drug treatments for patients with COVID-19-induced thrombosis is highlighted by the possibility that some of the COVID-19 therapies under development may have different drug-drug interactions with popular antithrombotic drugs.

In a recent trial by Kitchen et al. (2022), researchers observed changes in platelet aggregation—a process where blood platelets stick together to form a clot. In the control group, platelet aggregation increased over the 24-hour postoperative period, while in the 700-1100nm group (indicating the wavelength range used in the therapy), platelet aggregation either remained steady or decreased. This suggests that photobiomodulation using 1070nm light may have the potential to lower platelet aggregation, reducing the risk of fatal thrombosis.

Importantly, neither the combination therapy nor the delivery of photobiomodulation therapy (PBMt) had a discernible effect on the rise in hemorrhage incidence brought on by tPA (tissue plasminogen activator). This means that photobiomodulation didn't make bleeding more likely, making it a safe option either by itself or with another treatment called tPA, which is a medication used in medical settings, often in emergency situations like stroke, to break down blood clots with the aim to restore blood flow to the affected part of the body. 

Conclusion

The revelation that blood clots may be a driving force behind brain fog in Long COVID patients represents a significant breakthrough in our understanding of this perplexing condition.

As we continue to grapple with the aftermath of the COVID-19 pandemic, these findings offer hope for those experiencing cognitive issues, bringing us one step closer to effective treatments and solutions.

 

References

Bartell, P.A. 2020. Intense light as anticoagulant therapy in humans. Available Online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7775081/#:~:text=Our%20human%20studies%20revealed%20that,on%20platelet%20aggregation%20in%20mice

Bowen, R., Arany, P.R. 2023. Use of either transcranial or whole-body photobiomodulation treatments improves COVID-19 brain fog. Available Online: https://onlinelibrary.wiley.com/doi/10.1002/jbio.202200391

Doughty, B. 2023. Blood clots during COVID-19 may be a cause of ‘brain fog’. Available Online: https://www.mqmentalhealth.org/blood-clots-during-covid-19-may-be-a-cause-of-brain-fog/

Kitchen, L.C.; Berman, M.; Halper, J.; Chazot, P. Rationale for 1068 nm Photobiomodulation Therapy (PBMT) as a Novel, Non-Invasive Treatment for COVID-19 and Other Coronaviruses: Roles of NO and Hsp70. Int. J. Mol. Sci. 2022, 23, 5221. https://doi.org/10.3390/ijms23095221

Taquet, M. et.al. 2023. Acute blood biomarker profiles predict cognitive deficits 6 and 12 months after COVID-19 hospitalization. Available Online: https://www.nature.com/articles/s41591-023-02525-y