Many people who have long Covid experience a symptom known as “brain fog,” which includes forgetfulness and difficulties concentrating. Researchers now believe that this symptom could be caused by a leaky blood-brain barrier.
The blood-brain barrier is responsible for regulating the substances that enter and exit the brain. According to Prof Matthew Campbell of Trinity College Dublin, “It’s all about regulating a balance of material in blood compared to the brain. If that is off balance, then it can drive changes in neural function and wreak havoc, particularly in brain regions that are involved in memory consolidation and storage.”
In a study published in the journal Nature Neuroscience, Campbell and his colleagues analyzed serum and plasma samples from 76 patients who were hospitalized with Covid in March or April 2020, as well as samples from 25 individuals before the pandemic. Among their findings, they discovered that patients who self-reported brain fog had higher levels of a protein called S100β, which is produced by brain cells and is not normally found in the blood. This suggests that these patients had a breakdown of the blood-brain barrier.
In further investigations, the researchers recruited 10 people who had recovered from Covid and 22 people with long Covid, 11 of whom reported experiencing brain fog. MRI scans revealed that those with brain fog showed signs of a leaky blood-brain barrier, while those without this symptom or who had recovered did not.
The study also found that long Covid patients with brain fog exhibited increased levels of proteins involved in clotting. Prof Campbell suggests that disruptions to proteins involved in clotting may be linked to disruptions in the cells that line blood vessels. “The whole concept that a lot of these neurological conditions, including brain fog, could be treated by simply regulating the integrity of the blood-brain barrier is really exciting,” he said.
While the study focuses on long Covid patients, its results may have relevance to individuals experiencing brain fog due to other conditions such as ME. However, further extensive research would be required to confirm this.
The findings of this study are important in shedding light on the mechanisms underlying brain fog in patients with long Covid. Abnormalities in the blood vessels of the brain and abnormal blood clotting appear to contribute to this symptom. However, the study only involved patients from the first wave of Covid, so it remains uncertain whether the same mechanisms occur in individuals affected by later variants of the virus or those who have been vaccinated.
Although the small sample size and self-reporting of brain fog by participants in the study raise some limitations, the results have significant implications. They highlight the potential of regulating the integrity of the blood-brain barrier to alleviate neurological symptoms, including brain fog. This has far-reaching implications not only for long Covid patients but also for individuals affected by other conditions that involve brain fog.
Looking ahead, these insights into the role of the blood-brain barrier could lead to new therapeutic strategies and treatments for brain fog and other related neurological conditions. By targeting the integrity of the blood-brain barrier, researchers could potentially mitigate the debilitating effects of brain fog and improve cognitive function. This presents a promising avenue for future medical advancements.
Considering the broader context, the Covid-19 pandemic has brought attention to long-term effects and complications that can arise even after recovering from the acute phase of the illness. Brain fog, as a persistent symptom, warrants further research and understanding, not only in the context of Covid-19 but also in relation to other conditions. This knowledge can contribute to a better understanding of the underlying mechanisms and potentially pave the way for effective interventions.