“Brain fog” is a common experience among those with long-term symptoms of Covid, causing forgetfulness and trouble focusing. Recent studies suggest that this symptom may be linked to a weakened blood-brain barrier.

The barrier manages the flow of substances and materials in and out of the brain. According to Professor Matthew Campbell, a co-author of the study at Trinity College Dublin, it functions to maintain a balance between the materials in the blood and the brain.

If there is an imbalance, it can affect the functioning of the neurons. This can have a negative impact on brain areas responsible for memory storage and consolidation.

In a study published in the journal Nature Neuroscience, researchers led by Campbell examined blood samples from 76 individuals who were hospitalized due to Covid in March or April 2020. They also analyzed samples from 25 individuals before the pandemic began.

One of the team’s discoveries was that Covid patients who reported experiencing brain fog had higher levels of a protein called S100β in their samples compared to Covid patients without this symptom or individuals who did not contract Covid.

The brain cells produce this protein, which is typically absent in the blood. This indicates that these patients experienced a disruption of the blood-brain barrier.

10 individuals who had previously contracted Covid and 22 individuals experiencing long-term effects of the virus were selected by the researchers. Out of the 22, 11 reported experiencing brain fog. None of the participants had received a Covid vaccine or been hospitalized for the virus at the time of the study.

These individuals received an MRI scan where a contrast agent was injected through a vein.

The findings indicate that individuals with long-term effects of Covid-19 and impaired cognitive function exhibited evidence of a compromised blood-brain barrier, while those without this symptom or who had recovered did not.

According to Campbell, individuals with a more tightly sealed blood-brain barrier may have a higher level of protection against brain fog if they experience long-term effects of Covid. This could explain why not all patients experience this symptom.

Additional research in a subset of individuals discovered that those with long-term effects of Covid, such as brain fog, displayed indications of elevated amounts of clotting-related proteins.

According to Campbell, the findings were not unexpected since disturbances to proteins responsible for clotting could also cause issues with the cells that coat blood vessels. He expressed excitement about the potential for treating neurological conditions, such as brain fog, by regulating the strength of the blood-brain barrier.

Although the research primarily centers on individuals with long-term Covid, Campbell noted that the findings could also be applicable to those experiencing cognitive issues due to different illnesses, such as ME. However, further investigations would be necessary to verify this.

According to Prof Paul Harrison, a researcher from the University of Oxford who previously proposed that blood clots in the brain could be a contributing factor to brain fog in individuals with long Covid, the latest study holds significant significance.

According to him, the evidence suggests that individuals experiencing post-Covid brain fog also have irregularities in the blood vessel linings in their brain, further supporting the idea that abnormal blood clotting plays a role.

However, he stated that the findings were based on individuals who had contracted Covid during the initial outbreak, making it possible but uncertain if the same processes occurred in individuals with different variants of the virus or those who had been vaccinated.

Harrison stated that there are likely various processes that can account for brain fog and other symptoms associated with post-Covid syndrome.

According to Professor Claire Steves from King’s College London, the limited number of participants may have influenced the results and could have been a result of chance. Additionally, the concept of “brain fog” was not explicitly defined and was based on self-reported experiences of the participants.

She stated that it is challenging to determine the relevance of these findings to the large number of individuals who have encountered this occurrence.

Source: theguardian.com