Research adds additional evidence that nasal cells are the entry point for SARS CoV-2

Johns Hopkins scientists have conducted experiments on small numbers of human cell samples, and the cell “hooks” that SARS-CoV-2 uses to latch and infect cells are the cells that support olfaction. The lining reports up to 700 times more inside the upper nose and inside the cells of the inner wall of the trachea leading to the rest of the nose and lungs. These supporting cells are necessary for the function and development of odor sensing cells.

Findings from preliminary studies of cells lining both the nose and trachea could advance the search for the best target for topical or topical antiviral drugs to treat COVID-19, which could lead people with the virus to The scent that sometimes provides further clues to why you lose sensation.

A summary of the findings will be displayed in the letter Published in European Respiratory Journal..

“Loss of olfaction is commonly associated with COVID-19 in the absence of other nasal symptoms, and our study shows how and why it happens, and where we have some We may proceed with an investigation into the definitive reasons why we can most effectively direct the treatment of.” Head Professor of Head and Neck Surgery at Otorhinolaryngology and Director of Rhinology and Skull Base Surgery at Johns Hopkins University School of Medicine. Dr. Andrew Lane says.

Lane’s medical practice focuses on people who have problems with the nose and sinuses, who often lose their sense of smell-a condition called olfactory disorder.

Scientists know that SARS-CoV-2 hooks onto a biological hook on the surface of many types of human cells called the angiotensin converting enzyme 2 receptor (ACE2). Receptors involve essential molecules.

To explore the ACE2 link to COVID-19 in more detail, John Lane, a researcher at Lane’s laboratory at the Johns Hopkins University School of Medicine, Dr. Menfeiten, and other members of his team conducted an in-depth study. At ACE2 levels, in nasal tissue specimens of 19 adult men and women with chronic sinusitis (inflammation of nasal tissues) and in a control group of 4 patients who had nasal surgery for problems other than sinusitis ..

The researchers also studied tracheal tissue samples from 7 patients who had surgery because of an abnormal narrowing of the trachea.

Cells from children tend to have lower ACE2 levels in the cells that line the nose, which may contribute to less commonly severe illness among children infected with the SARS-CoV-2 virus, so in this study It was not inspected. None of the study participants had been diagnosed with COVID-19.

Scientists used a high-resolution imaging technique called a confocal microscope to create a very sharp image of the cells that line the airways of the nose and trachea. They used fluorescent staining to identify the ACE2 receptor.

They found high levels of ACE2 in nasal cells that provide structural support called feeder cells. These cells are located in a region called the olfactory neuroepithelium called olfactory neurons. Researchers say this area of ​​the nose may be particularly vulnerable to infection and may be the only site of infection even in the absence of symptoms. Because of this, they encourage people to wear masks and wear them properly.

The study showed a 200- to 700-fold increase in ACE 2 protein in cells of the olfactory neuroepithelium in response to biopsy samples compared to other samples from the nose and trachea. Because cells with high levels of ACE2 are associated with odor sensing, researchers may say that infection with these cells is why some people with COVID-19 experience a loss of olfaction. Suggests that

Two of the seven trachea specimens had low levels of ACE2 receptors, and the amount of these receptors was similar among study participants with and without chronic nasal sinuses.

Since the cells covering the nose may prove to be important entry points for SARS-CoV-2, lanes targeted these specific cells directly to that area with topical antiviral drugs or other treatments There may be a way to make it happen.

Researchers will proceed with this study by investigating tissues infected with COVID-19 from the human nose to see if the SARS-CoV-2 virus actually targets nasal feeder cells.

Reissued by courtesy of Johns Hopkins Medicine. Photo: ACE2 for Red Stain. The green probe stains feeder cells and CK18 in the mucous glands. Credit: Mengfei Chen