The reason for the loss of smell explained «kleinezeitung.at

Loss of smell as a result of SARS-CoV-2 infection occurs repeatedly. It now seems clear how this happens.

12:32 PM Mar 07 2022

olfactory disorders They are in many cases the main symptom of SARS-CoV-2 infection. So far, science has assumed that the cause is nerve cell damage in the epithelial cell layer of the upper respiratory tract. According to American scientists, laboratory experiments on tissue samples from Covid 19 patients and infected hamsters show a different picture: The defects affect the supporting cells and as a result only impair the function of the neurons.

“SARS-CoV-2 infects less than one percent of the cells of the human body. Despite this, it can cause severe damage to an entire range of organs. Neurological and cognitive disorders They are among the least understood symptoms of Covid-19 patients. Among them, disturbances in the sense of smell are the most common. marianna zazytska (Columbia University / New York) and their co-authors a few days ago in the journal Cell.

led scientists Studies on olfactory epithelial samples of SARS-CoV-2 patients and infected hamsters. “Accordingly, the hamster started as a result of the injury Strong immune reaction A, resulting in localized inflammation and It destroys olfactory receptors and proteins on the surface of nerve cells in the nosethat recognize and transmit information about odors. About ten days after the injury, this colossal disorder was corrected again,” wrote the German Pharmaceuticals Zeitung (online).

Anyway, the cause of smell and taste disorders More complicated than originally thought. According to American scientists, the cells supporting the layer of glandular cells and the covering (epithelium) of the upper respiratory tract were the first to be infected with the Covid-19 virus. a loss of neuronswhich records or transmits odor information, experts have been able to don’t prove. Obviously anemia is one Indirect collateral damage.

“Obviously one was enough Infection of neighboring cells outside to alter the function of nearby neurons. Effects unfolded over Significant downregulation of olfactory receptor genes and other key genes of the olfactory receptor signaling pathway. This was confirmed by analysis of the olfactory epithelium of 23 patients with Covid-19”, writes the German Pharmaceutical Journal.

The results of laboratory studies by American neurologists seem to confirm this once again In the long run, the inflammatory reaction caused by the SARS-2 virus is the main problem of Covid-19 After the acute “viral” stage of the disease. The loss of smell and taste as a result of Covid-19 appears to be ‘collateral damage’ caused by a Overreaction of the immune system Happen or occur. It is activated by infection and leads to an endogenous excessive production of inflammatory messenger substances. Then the consequences Tissue or organ damage.

Hope for a cure

“Maybe such indirect mechanisms It also explains some of the longstanding coronavirus diseaseswhich can last for weeks or months after infection with the SARS-CoV-2 virus,” said Germany’s Pharmaceuticals-Zeitung. First writer Mariana Zasicka spoke to The New York Times about the hope that olfactory neurons will recover after overcoming COVID-19-disease He can also recover.