Study Explains How Coronavirus Spreads Into The Brain

SARS-CoV-2 can infect both nerve cells or neurons, and the cells in the brain and spinal cord that support and protect neurons (astrocytes).

"Our findings suggest that astrocytes are a pathway through which COVID-19 causes neurological damage," said Ricardo Costa, PhD, a postdoctoral fellow at the Louisiana State University (LSU) Health Shreveport and the study's first author.

‘Few astrocytes getting infected could be sufficient for the COVID-19 to quickly spread to neurons and multiply. This is the reason why some patients do not have any neurological symptoms and others seem to have severe ones.’

"This could explain many of the neurologic symptoms we see in COVID-19 patients, which include loss of sense of smell and taste, disorientation, psychosis and stroke."

SARS-CoV-2 infect a person's cells by grabbing angiotensin-converting enzyme-2 (ACE2) receptors. For the study, Costa and colleagues examined RNA and proteins to determine whether cell cultures of human astrocytes and neurons expressed ACE2 (angiotensin-converting enzyme-2).

Studies confirmed that both astrocytes and neurons express the ACE2 receptor and that both cell types can become infected with SARS-CoV-2, though astrocytes were less likely to become infected.

By resisting infection, astrocytes could help keep SARS-CoV-2 out of the brain, but once infected, they could easily pass the virus along to many neurons, according to researchers.

"While astrocytes display a higher resistance to infection, neurons seem to be more susceptible," said Costa.

"This suggests that only few astrocytes getting infected could be sufficient for the infection to quickly spread to neurons and multiply quickly. These observations could explain why while some patients do not have any neurological symptoms, others seem to have severe ones."

Source: Medindia