Berlin. Originally called a lung virus, it is now clear: Sars-CoV-2 is more than that, it is a multi-organ virus. In addition to the lungs, researchers were able to detect the pathogen in the brain, among other things. But how does the corona virus get there?
Experts in neuropathology, pathology, forensic medicine, virology and clinical care at the Charité in Berlin have explored this question. They analyzed tissue samples from 33 people who died related to Sars-CoV-2. They published their results in the journal Nature Neuroscience, which show that the nerve cells in the olfactory mucosa transmit the coronavirus to the brain.
For the first time intact corona particles are made visible
In their study, the scientists also examined individual cells in which they searched for the genetic material of the coronavirus and its spike protein. The highest viral load was eventually found in the olfactory mucosa. Using special stains and electron microscope images, the researchers were able to visualize intact coronavirus particles for the first time. These particles were detectable both in nerve cells and on the extensions of the covering cells in the olfactory mucosa.
“Based on this data, we believe that Sars-CoV-2 can use the olfactory mucosa as a gateway to the brain,” said Prof. Frank Heppner, director of the Institute of Neuropathology at Charité, in a statement from the university. “From the olfactory mucosa, the virus apparently uses neuroanatomical compounds such as the olfactory nerve to reach the brain.”
Coronavirus can migrate from nerve cell to nerve cell
However, the neuropathologist points out that the study only examined corona patients who had a severe course of the disease during their lifetime and subsequently 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 exactly how Sars-CoV-2 moves from the nerve cells. “Our data suggests that the virus migrates from nerve cell to nerve cell to reach the brain,” said neuropathologist Helena Radbruch of Charité, who also participated in the study. “The virus is presumably also transported through the vascular system at the same time, since the virus can also be detected in the vessel walls of the brain.”