Research carried out by teams of researchers from different entities revealed that the SARS-CoV-2 virus was indeed capable of infecting neurons . Previously, neurological symptoms such as headaches, loss of smell, loss of consciousness and even stroke had been reported in several Covid-19 patients, but the ability of the coronavirus to attack brain cells had not yet been demonstrated.
Thus, it was not yet proven that these symptoms indeed result from the infection of brain cells by the coronavirus, although traces of viral RNA have been found in the brains of some victims of the disease. Traces of viral proteins have also been detected in cells of their olfactory bulb.
The new study was to determine the ability of SARS-CoV-2 to infect brain cells. It was conducted by scientists from Yale University in the United States, the Brain Institute of Sorbonne University / Inserm / AP-HP / CNRS and the Pitié-Salpêtrière AP-HP hospital. The results were published in the Journal of Experimental Medicine on January 12, 2021.
Several experiments carried out
In order to verify their hypothesis, the researchers turned to three types of approaches. The first was to grow brain cells in 3D while the second was based on a mouse model of infection with the Covid-19 virus. The last approach was to analyze brain tissue from patients who died from SARS-CoV-2 infection.
In 3D cultures, scientists have found that the coronavirus can penetrate into neurons and multiply there. While the infection does not directly kill brain cells, it can cause metabolic changes in the cells. On the other hand, the neighboring cells of the contaminated neurons would gradually die due to the lack of oxygen.
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Results of the mouse model of SARS-CoV-2 infection
The results obtained in previous studies suggest that the ACE2 protein located on the cell surface plays an important role in the infection of cells by SARS-CoV-2. Although this receptor is present in large quantities in the lungs, the organs most attacked by the virus, the mouse model of SARS-CoV-2 infection has also demonstrated its importance in the infection of brain cells.
The researchers also noted that the vascular network of infected regions of the brain was undergoing a major change. The explanation suggests that there may be a link between entry of the virus into neurons seen in brain cell cultures and brain tissue from deceased patients, and neurological symptoms such as hypoxia and ischemic attacks.
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While the results obtained during the study were able to confirm the ability of SARS-CoV-2 to infect brain cells, the researchers suggest continuing research to confirm the link between the various neurological symptoms observed and the changes in the brain. level of infected cells. They believe that determining the method the virus uses to reach the brain would also be essential.