Can COVID-19 Also Enter the Central Nervous System?

The virus is known to invade human cells through the ACE2 receptor-driven pathway, primarily impacting the respiratory tract.

In a recent review, published in the journal Cell, investigators from Cleveland Clinic's Department of Biomedical Engineering have studied case reports of neurological symptoms associated with the coronavirus disease 2019 (COVID-19). Although the disease is known mostly as a respiratory one, with symptoms including shortness of breath, cough and in some cases acute respiratory distress syndrome, cases impacting the central nervous system (CNS) have been documented.

"Ordinarily, the blood-brain barrier allows nutrients to reach the brain while protecting it from circulating toxins or pathogens that could cause infections," Chaitali Ghosh, a lead author on the study said. "However, the exact mechanisms underlying COVID-19-associated neurological disorders remain unknown. Such viral infectivity could alter blood-brain barrier function, which may influence disease progression."

When the virus enters the CNS, it activates the proteins known as cytokines, which are a response from the body’s immune system. This in turn may cause the cytokine storm, which is known to cause inflammation and can lead to a severe case of COVID-19.

The investigators state that although there is a limited amount of evidence on long-term consequences of neurodegenerative and inflammation-mediated brain diseases associated with COVID-19, the evidence supports further study into whether these comorbidities are risk factors for the disease.

"I am eager to define and learn more about which signaling pathways are linked to which neurological disorders, and think this will be an exciting new frontier in COVID-19 research," Ghosh said.