Berlin. It was originally called a lung virus, but it’s now obvious: Sars-CoV-2 is more than that, it’s a multi-organ virus. In addition to the lungs, researchers were also able to detect, among other things, the pathogen in the brain. But how does the coronavirus get there?
Experts in neuropathology, pathology, forensic medicine, virology and clinical care at Charité Berlin have investigated this question. They analyzed tissue samples from 33 deceased in association with Sars-CoV-2. In the journal Nature Neuroscience, they published their results, which show that the nerve cells in the olfactory mucosa transmit the coronavirus to the brain.
For the first time whole corona particles visible
During their investigations, the scientists also investigated individual cells where they looked for the genetic material of the coronavirus and its spike protein. Eventually the highest viral load was found in the olfactory mucosa. With the help of special stains and electron microscopic images, the researchers were able to make whole coronavirus particles visible for the first time. These particles were found inside nerve cells and on extensions to the cover cells in the olfactory mucosa.
“Based on these data, we assume that Sars-CoV-2 can use the olfactory mucosa as a portal to the brain,” said Professor Frank Heppner, director of the Institute of Neuropathology at the Charité, in a communication from the university. “From the olfactory mucosa, it is likely that the virus uses neuroanatomical connections such as the olfactory nerve to reach the brain.”
A coronavirus can migrate from nerve cell to nerve cell
The neuropathologist notes, however, that the study only examined corona patients who showed a serious course of the disease during their lifetime and died as a result of the disease. “Therefore the results of our study cannot necessarily be transferred to mild or moderate cases.”
It is also largely unclear how exactly Sars-CoV-2 moves from the nerve cells. “Our data suggests that the virus migrates from nerve cell to nerve cell to get to the brain,” says neuropathologist Helena Radbruch of Charité, who also participated in the study. “However, it is likely that the virus was also carried through the blood vessel system at the same time, as the virus could also be detected in the vascular walls in the brain.”