(ORDO NEWS) — A small new study published on Tuesday by scientists at the US National Institutes of Health suggests that the immune response triggered by coronavirus infection damages the blood vessels in the brain and may be responsible for long-lasting symptoms of COVID.
The work, published in the journal Brain, was based on autopsies of the brains of nine people who died suddenly after being infected with the virus.
Instead of finding traces of the SARS-CoV-2 virus in the brain, the team found that people’s own antibodies attacked the cells lining the brain’s blood vessels, causing inflammation and damage.
The discovery could explain why some people continue to experience the effects of the infection, including headache, fatigue, loss of taste and smell, inability to sleep, and brain fog, and could help develop new treatments for long-term COVID.
NIH scientist Avindra Nath, senior 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 have previously shown blood vessel damage and inflammation in the brains of patients at autopsy, but we did not understand the cause of the damage. I think that in this work we have gained an important insight into the cascade of events.”
Nine people, aged 24 to 73, were selected from the team’s previous study because they showed signs of damage to blood vessels in the brain based on scans.
Their brains were compared to those of 10 controls, and the team examined neuroinflammation and immune responses using immunohistochemistry.
Scientists have found that antibodies produced against COVID-19 misdirectedly target cells that form the “blood-brain barrier,” a structure designed to keep harmful agents out of the brain while allowing essential substances to pass through.
Damage to these cells can cause proteins to leak, bleed, and clot, which increases the risk of stroke.
Leaks also trigger immune cells called macrophages that rush to the site of damage to repair it, causing inflammation.
The team found that the normal cellular processes in the attacked areas were severely disrupted, affecting things like their ability to detoxify and regulate their metabolism.
The results provide insight into the biology at work in patients with long-term neurological symptoms and could help develop new therapies, such as drugs that target the accumulation of antibodies at the blood-brain barrier.
It’s possible that the same immune response persists in long-term COVID patients, leading to neuronal damage, says Nath.
This means that a drug that lowers the immune response could help such patients, he added.
“So these results have very important therapeutic implications.”
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