NIH Study Finds Damage, Inflammation Of Blood Vessels In Brains Of COVID-19 Patients, But No Infection

Press release

Wednesday, December 30, 2020

The results of a study of 19 deceased patients suggest that brain damage is a byproduct of a patient’s illness.

In an in-depth study of how COVID-19 affects a patient’s brain, researchers at the National Institutes of Health have consistently spotted signs of damage from thinning and leaking brain blood vessels in samples tissue from patients who died shortly after contracting the disease. Additionally, they saw no signs of SARS-CoV-2 in the tissue samples, suggesting the damage was not caused by a direct viral attack on the brain. The results were published in correspondence form in the New England Journal of Medicine.

“We have found that the brains of patients who acquire SARS-CoV-2 infection may be sensitive to microvascular damage to the blood vessels. Our results suggest that this may be caused by the body’s inflammatory response to the virus, ”said Avindra Nath, MD, clinical director at the National Institute of Neurological Disorders and Stroke (NINDS) at NIH and lead author of the study. “We hope these results will help physicians understand the full spectrum of problems patients may suffer so that we can provide better treatments.”

Although COVID-19 is primarily a respiratory disease, patients often experience neurological issues such as headaches, delirium, cognitive dysfunction, dizziness, fatigue, and loss of smell. The disease can also cause strokes and other neuropathologies.

Several studies have shown that the disease can cause inflammation and damage to blood vessels. In one of these studies, researchers found evidence of small amounts of SARS-CoV-2 in the brains of some patients. Nevertheless, scientists are still trying to understand how the disease affects the brain.

In this study, researchers performed an in-depth examination of brain tissue samples from 19 patients who died after suffering from COVID-19 between March and July 2020. Samples from 16 of the patients were provided by the Medical Examiner’s Office in head of New York, while the other 3 cases were provided by the Department of Pathology at the University of Iowa College of Medicine, Iowa City. The patients died at a wide variety of ages, from 5 to 73 years old. They died within hours to two months of reporting symptoms. Many patients had one or more risk factors, including diabetes, obesity, and cardiovascular disease. Eight of the patients were found dead at home or in public places. Three other patients collapsed and died suddenly.

Initially, the researchers used a special high-power magnetic resonance imaging (MRI) scanner, 4 to 10 times more sensitive than most MRI scanners, to examine odor bulb and brainstem samples from each. patient. These regions are believed to be very susceptible to COVID-19. Olfactory bulbs control our sense of smell while the brainstem controls our breathing and heart rate. Scans found that both regions had an abundance of bright spots, called hyperintensities, which often indicate inflammation, and dark spots, called hypointensities, which represent bleeding.

The researchers then used the scans as a guide to take a closer look at the spots under a microscope. They found that the bright spots contained thinner-than-normal blood vessels and sometimes leaked blood proteins, like fibrinogen, into the brain. It seems 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 coagulated and leaky blood vessels, but no immune response.

“We were completely surprised. We originally expected to see damage from a lack of oxygen. Instead, we saw multifocal areas of damage typically associated with stroke and neuro-inflammatory disease, ”Dr. Nath said.

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

“So far, our results suggest that the damage we have seen may not have been 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 blood vessels in the brain and whether it produces some of the short and long term symptoms that we see in patients.”

This study was supported by the NIH Intramural Research Program at the National Institute of Neurological Disorders and Stroke (NS003130) and a grant from NIH (NS109284).

NINDS (https://www.ninds.nih.gov) is the largest funder of brain and nervous system research in the country. The mission of NINDS is to research fundamental knowledge about the brain and nervous system and to use this knowledge to reduce the burden of neurological disease.

About the National Institute on Aging (NIA): The NIA leads the efforts of the US federal government to conduct and support research on aging and the health and well-being of older adults. Learn more about age-related cognitive changes and neurodegenerative diseases via the website of NIA’s Alzheimer’s and related Dementias Education and Referral Center (ADEAR) Center. For more information on a wide range of aging-related topics, visit NIA’s main website and stay connected.

About the National Institutes of Health (NIH):NIH, the nation’s medical research agency, comprises 27 institutes and centers and is a component of the US Department of Health and Human Services. The NIH is the primary federal agency that conducts and supports basic, clinical, and translational medical research, and studies the causes, treatments, and cures for common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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