Studies look at how COVID-19 invades the brain in severe cases

According to a new study in Toronto-Berlin, the most common route that a new coronavirus follows when it invades the brain is through the nose.

SARS-CoV-2, the virus that causes COVID-19, is known to be primarily a respiratory virus, but at this stage of the pandemic, the virus is found in other parts of the body, from the cardiovascular system to the cardiovascular system. It is currently recognized to affect many areas. brain.

More than one-third of COVID-19 patients report neurological symptoms such as headache, brain fog, and loss of smell and taste, and some patients even experience a stroke associated with the disease.

However, researchers haven’t investigated in detail how the virus invaded the brain until this study.

Published on Monday Journal Nature NeuroscienceIn this study, we examined tissue samples of 33 patients who died after being infected with COVID-19.

To track how the virus reached the brainstem, researchers examined many areas of the brain and the structure of the skull, which connects the eyes, mouth, and nose to the brainstem.

They specifically searched for SARS-CoV-2 genetic material, as well as spike proteins on the surface of the virus. Evidence of the virus was found throughout the structure that connects the brain to the eyes, mouth, and nose, but the highest viral load was found in the olfactory mucosa, which is the upper part of the nasal cavity.

“Using special tissue staining, researchers were able to create the first electron micrographs of intact coronavirus particles in the olfactory mucosa.” The press release states.

The image itself shows a yellow mass of virus attacking pink nerve cells.

Dr. Frank Heppner, Dean of the Department of Neuropathology at Charitie-Universitätsmedizin Berlin, said in a release that the data was “[s] The idea that SARS-CoV-2 can use the olfactory mucosa as an entry point into the brain.

“Once inside the olfactory mucosa, the virus appears to use neuroanatomical connections such as the olfactory nerve to reach the brain.”

Researchers believe that the virus passes through nerve cells to reach the brain, but the pattern of complete movement is unknown and may involve transport through blood vessels.

“Evidence of the virus was also found on the walls of blood vessels in the brain,” said Dr. Helena Bradbunch of the Department of Neuropathology in a presentation.

Another aspect of the study focused on the immune response of the brain itself. The study found that there were activated immune cells in both the brain and nasal passages, and in some cases there was tissue damage caused by the stroke.

Researchers say that the loss of taste and odor experienced by many COVID-19 patients is likely due to the presence of COVID-19 in the olfactory mucosa.

COVID-19 in the brain can also have serious consequences. Researchers have discovered SARS-CoV-2 in “a region of the brain that controls important functions such as breathing.”

“In patients with severe COVID-19, the presence of the virus in these areas of the brain has a deteriorating effect on respiratory function, and it cannot be ruled out that respiratory problems due to SARS-CoV-2 infection in the lungs increase.” Said Hepner.

The researchers identified that the study results could not be extrapolated to mild cases because their research group included only severe cases that died after being infected with COVID-19.

However, the results prompt further research on the question of how the virus travels through the body and how the nasal cavity plays a role.

The issue of nose and COVID-19 has recently been raised by other researchers. A paper published in Frontiers in Immunology on Monday argued that more research was needed on how the virus-related immune response occurs in the mucous membranes of the nose and mouth.

The mucosal immune system as a whole is the largest component of the human body’s immune system, the paper’s publication states. Much of the COVID-19 study is directed to the lower respiratory tract, especially the lungs, where more severe cases have seizures, but less research has been done on the upper respiratory tract and its specific immune response.

The authors theorized that examining mucosal immunity could better clarify how and why some people remain asymptomatic despite the presence of the virus in the system. ..

“Is this due to an early mucosal immune response that succeeded in containing and eliminating the infection before it became serious?” Michael W. Russell, Jacobs Medical College and Biomedical Sciences at Buffalo University Professor, Said in a press release. “We don’t know unless we address these questions.”