A small study published by scientists at the US National Institutes of Health suggests that the immune response caused by coronavirus infection damages the blood vessels of the brain and may be the cause of long-term symptoms of COVID-19.
The new work was based on the results of autopsies of the brains of nine people who died from COVID-19.
Instead of signs of the SARS-CoV-2 virus in the brains of the deceased, scientists found people’s own antibodies that attacked the cells lining the blood vessels of the brain, causing inflammation and damage.
This discovery may explain why some people still have the effects of infection, including headache, fatigue, loss of taste and smell, inability to fall asleep, as well as “brain fog”. But the main thing is that this work can help develop new methods of treating long-covid.
Avindra Nath, senior author of the article, stated: “Patients often develop neurological complications in COVID-19, but the underlying pathophysiological process has not been sufficiently studied. Previously, we showed damage to blood vessels and inflammation in the brain of patients at autopsy, but we did not understand the reason for this. I think we have now gained an important insight into the sequence of events.”
As part of the work, were investigated ?9 people aged from 24 to 73 years. The scientists chose them because the scans indicated signs of damage to blood vessels in the brain.
Their brains were compared with a control group (10 people), the team studied neuroinflammation and immune responses using a method called immunohistochemistry.
Scientists have discovered that antibodies produced against COVID-19 mistakenly attacked cells that form the “blood—brain barrier” – a structure designed to prevent harmful substances from entering the brain. Damage to these cells can cause “leakage” of proteins, bleeding and the formation of blood clots, which increases the risk of stroke.
Leaks also cause immune cells called macrophages to rush to the injury site to repair the damage, causing inflammation. The team found that normal cellular processes in the areas under attack were severely disrupted, with implications for processes such as toxin removal and metabolic regulation.
The results obtained give an idea of the processes occurring in the brain in patients with long-term neurological symptoms, which can serve as the basis for new treatment methods. For example, a drug that aims to restore the work of the blood-brain barrier.