Study Finds Blood Vessel Damage and Inflammation in Brains of Patients With COVID-19, But No SARS-CoV-2 Infection

In an in-depth study of how coronavirus disease 2019 (COVID-19) affects a patient’s brain, researchers consistently spotted hallmarks of damage caused by thinning and leaky brain blood vessels in tissue samples from patients who died shortly after contracting the disease.

However, they saw no signs of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the tissue samples, suggesting the damage was not caused by a direct viral attack on the brain.

“We found that the brains of patients who contract infection from SARS-CoV-2 may be susceptible to microvascular blood vessel damage,” said Avindra Nath, MD, National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, Bethesda, Maryland. “Our results suggest that this may be caused by the body’s inflammatory response to the virus. We hope these results will help doctors understand the full spectrum of problems patients may suffer so that we can come up with better treatments.”

For the study, published in The New England Journal of Medicine, the researchers conducted an in-depth examination of brain tissue samples from 19 patients aged 5 to 73 years who had died after experiencing COVID-19 between March and July 2020. Samples from 16 of the patients were provided by the Office of the Chief Medical Examiner in New York City while the other 3 cases were provided by the department of pathology at the University of Iowa College of Medicine, Iowa City, Iowa. Patients died within a few hours to 2 months after reporting symptoms. Many patients had ≥1 risk factors, including diabetes, obesity, and cardiovascular disease. Eight of the patients were found dead at home or in public settings. Another three patients collapsed and died suddenly.

Initially, the researchers used a special, high-powered magnetic resonance imaging (MRI) scanner that is 4 to 10 times more sensitive than most MRI scanners to examine samples of the olfactory bulbs and brainstems from each patient. These regions are thought to be highly susceptible to COVID-19. The scans revealed that both regions had an abundance of bright spots (hyperintensities) and darks spots (hypointensities). The researchers then used the scans as a guide to examine the spots more closely under a microscope.

They found that the bright spots contained blood vessels that were thinner than normal and sometimes leaking blood proteins, like fibrinogen, into the brain. This appeared to trigger an immune reaction. The spots were surrounded by T cells from the blood and the brain’s own immune cells called microglia. In contrast, the dark spots contained both clotted and leaky blood vessels but no immune response.

“We were completely surprised,” said Dr. Nath. “Originally, we expected to see damage that is caused by a lack of oxygen. Instead, we saw multifocal areas of damage that are usually associated with strokes and neuroinflammatory diseases.”

Finally, the researchers saw no signs of infection in the brain tissue samples even though they used several methods for detecting genetic material or proteins from SARS-CoV-2.

“So far, our results suggest that the damage we saw may not have been not caused by the SARS-CoV-2 virus directly infecting the brain,” said Dr. Nath. “In the future, we plan to study how COVID-19 harms the brain’s blood vessels and whether that produces some of the short- and long-term symptoms we see in patients.”

source: https://dgnews.docguide.com/study-finds-blood-vessel-damage-and-inflammation-brains-patients-covid-19-no-sars-cov-2-infection?overlay=2&nl_ref=newsletter&pk_campaign=newsletter&nl_eventid=26595&nl_campaignid=1607&MemberID=301406406