Small study sheds light on how COVID-19 affects the brain – SILive.com

A small National Institutes of Health (NIH) study found the bodys immune response to COVID-19 may be involved with inflammation and damage to the brain, adding to a growing body of evidence that ties the disease to an increased risk of neurological damage.

NIH researchers from the National Institute of Neurological Disorders and Stroke (NINDS) examined brain tissue from nine people who suddenly died from COVID-19 between March and July 2020 the first wave of the pandemic, according to the study published in the journal Brain.

The patients, who were between the ages of 24 and 73, were selected because they showed signs of blood vessel damage in the brain. They were then compared with a control group for signs of inflammation and immune responses.

The study found evidence that antibodies produced by the immune system in response to the virus were involved in an attack on the cells lining the brains blood vessels, causing inflammation and damage, even though the disease was not directly found in the brain.

Patients often develop neurological complications with COVID-19, but the underlying pathophysiological process is not well understood, Dr. Avindra Nath, clinical director at NINDS and the senior author of the study, said in a release. We had previously shown blood vessel damage and inflammation in patients brains at autopsy, but we didnt understand the cause of the damage. I think in this paper weve gained important insight into the cascade of events.

Scientists have been working to uncover the mechanisms that cause issues like brain fog and fatigue that are among the symptoms tied to long COVID the designation given to symptoms that persist after initial infection.

Some studies found lasting neurological issues for survivors that persisted for more than a year, and others discovered connections between the disease and tissue damage in the brain related to smell.

The most recent research suggests the body may be mistakenly targeting endothelial cells in the blood-brain barrier that are crucial to keeping harmful invaders away from the brain. Damage to these cells could cause proteins to leak from the blood, ultimately increasing the risk of stroke, the researchers said.

The NINDS researchers found damage to these cells and evidence of blood proteins that normally do not cross the blood-brain barrier. Those protein clusters are typically caused when endothelial cells activate and release molecules that stick together, suggesting antibodies were the cause of the attack.

By building off past research that showed COVID-19 damaged the brain by causing thinning and leaky blood vessels, the new findings bolster the belief that the bodys natural immune response could be the source of damaging and dangerous inflammation.

Activation of the endothelial cells brings platelets that stick to the blood vessel walls, causing clots to form and leakage to occur. At the same time the tight junctions between the endothelial cells get disrupted causing them to leak, said Nath. Once leakage occurs, immune cells such as macrophages may come to repair the damage, setting up inflammation. This, in turn, causes damage to neurons.

The researchers believe the patients used in the study would have developed long COVID if they survived. They added the study sheds light on the underlying mechanism causing neurological damage and could better enable doctors to treat long-term symptoms.

It is quite possible that this same immune response persists in long COVID patients resulting in neuronal injury, added Nath, who noted that the findings could have very important therapeutic implications.

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Small study sheds light on how COVID-19 affects the brain - SILive.com