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They discover a key factor why children do not have severe symptoms of COVID-19

One of the greatest certainties regarding the coronavirus is that affects mainly and with greater severity the elderly and adults. Or on the contrary, that children do not usually have severe symptoms. And that is by a reason that has been found by researchers at Vanderbilt University Medical Center (Canada).

Based on their findings, the coronavirus uses an enzyme and a co-receptor to invade the epithelial cells of the respiratory tract found in the lung. And precisely children have lower levels of it, as explained in the prestigious scientific journal Journal of Clinical Investigation.

The receptor, called ACE2 and located in some lung cells, is the one that intercepts protein “spikes” sticking out of the virus inhaled. And subsequently, the TMPRSS2 enzyme is responsible for cutting the protein from the “spikes” and thus fusing the virus in the cell membrane to enter the cell. Inside, the virus makes copies of the RNA of it.

Tests with mice and deceased patients

Looking at the investigation, it was key find the relationship between the enzyme mentioned and the severity of symptoms to see how it affected adults and children differently. “Our study provides a biological rationale for why particularly infants and very young children appear to be less likely to become infected or have severe symptoms of the disease, “says Jennifer Sucre, one of the authors of the theory.

To reach that conclusion, the reaction of the genes and their expression in mouse and human lungs were analyzed. “What we found is that TMPRSS2 expression increases significantly with aging, and we see it at the gene level and at the protein level. We see much more TMPRSS2 in older individuals, both in humans and mice”, Explains Sucre.

Besides that, Fluorescent probes were also used to analyze the corpses of three patients who died from COVID-19, and the virus was found in three types of cells that expressed TMPRSS2. This enzyme is usually common in prostate cancer, which is why many of the drugs that have been tested against this cancer in an advanced stage are also being clinically tested against the coronavirus.