RTL Today – New US study helps demystify Covid brain fog


A small new study published Tuesday by scientists at the US National Institutes of Health suggests that the immune response triggered by coronavirus infections damages blood vessels in the brain and may be responsible for long-lasting Covid symptoms.

The article, published in the journal Brain, was based on brain autopsies of nine people who died suddenly after contracting the virus.

Rather than detecting evidence of Covid in the brain, the team found that it was people’s own antibodies that attacked the cells lining blood vessels in the brain, causing inflammation and damage.

This discovery could explain why some people have lingering effects from the infection, including headaches, fatigue, loss of taste and smell, and inability to sleep as well as “brain fog” – and can also help design new treatments for the long Covid.

NIH scientist Avindra Nath, lead author of the paper, said in a statement, “Patients often develop neurological complications with COVID-19, but the underlying pathophysiological process is not well understood.”

“We had previously shown blood vessel damage and inflammation in the patients’ brains at autopsy, but we did not understand the cause of the damage. I believe that in this article, we gained important insights into the cascade of events.”

The nine people, aged 24 to 73, were selected in the team’s previous study because they showed signs of damage to blood vessels in their brains based on scans.

Their brains were compared to those of 10 controls, with the team looking at neuroinflammation and immune responses using a technique called immunohistochemistry.

Scientists have found that antibodies produced against Covid-19 mistakenly target cells that form the ‘blood-brain barrier’ – a structure designed to block harmful invaders from entering the brain while allowing necessary substances to pass.

Damage to these cells can cause protein leakage, bleeding and clots, increasing the risk of stroke.

The leaks also prompt immune cells called macrophages to rush to the site to repair the damage, causing inflammation.

The team found that normal cellular processes in the areas targeted by the attack were severely disrupted, with implications for things like their ability to detoxify and regulate metabolism.

The findings offer clues to the biology at play in patients with long-term neurological symptoms and may inform new treatments – for example, a drug that targets antibody buildup on the blood-brain barrier.

“It’s entirely possible that this same immune response persists in patients with Long COVID, resulting in neuronal injury,” Nath said.

This would mean that a drug that reduces this immune response could help these patients, he added. “So these findings have very important therapeutic implications.”


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