Involvement of the nervous system in COVID-19: The bell should toll in the brain

Abstract

The world is fuming at SARS-CoV-2 for being the culprit for causing the devastating COVID-19, claiming millions of lives across the globe in the form of respiratory disorders. But lesser known are its effects on the CNS that are slowly surfacing in the worldwide population. Our review illustrates findings that claim SARS-CoV-2's arrival onto the ACE2 receptors of neuronal and glial cells mainly via CSF, olfactory nerve, trigeminal nerve, neuronal dissemination, and hematogenous pathways. The role of SARS-CoV-2 structural proteins in its smooth viral infectivity of the host cannot be ignored, especially the spike proteins that mediate spike attachment and host membrane fusion. Worth mentioning the nucleocapsid, envelope, and membrane proteins make the proliferation of SARS-CoV-2 much simpler than expected in spreading infection. This has led to catastrophic conditions like seizures, Guillain-Barré syndrome, viral encephalitis, meningoencephalitis, acute cerebrovascular disease, and respiratory failures. Placing a magnifying lens on the lesser-explored CNS consequences of COVID-19, we attempt to shift the focus of our readers onto the new supporting threats to which further studies are needed.

JAK-STAT Pathway Inhibition and their Implications in COVID-19 Therapy

“…The alveolar epithelium cells in the lungs express Type1 and Type 2 pneumocyte cells [ 21 ]. SARS-COV-2 infects type 2 pneumocytes in the alveolar epithelium, abundant in ACE2 receptors, thus promoting effective binding onto the lung tissue [ 22 , 23 ].…”

COVID-19: a new emerging respiratory disease from the neurological perspective

“…4 ), directly via the transsynaptic route (olfactory bulb, the only part of the CNS not protected by dura), indirectly through hematogenous dissemination (Huang et al 2020 ; Chigr et al 2020 ; Das et al 2020 ), through neuronal retrograde dissemination or the trans-cribrial route (Baig and Sanders 2020 ), through the trigeminal nerve, peripheral nerves, the CSF or via the nerve ending in gastro-intestinal tract (gut–brain axis). All these routes were proposed based on current evidences (Satarker and Nampoothiri 2020 ; Tremblay et al 2020 ; Lima et al 2020 ; Jakhmola et al 2020 ). The second pathway is the hematogenous dissemination; this, in turn, takes place via different possibilities: (1) Transported to CNS through infected vascular endothelial cells, which normally express ACE2 receptors.…”

The Other Side of SARS-CoV-2 Infection: Neurological Sequelae in Patients

“…The first case of COVID-19 initially associated with acute GBS was reported by Zhao et al ( 2020 ). To date, 50 GBS patients, or its variants, and COVID-19 have been reported (for review, see Katyal et al, 2020 ; Satarker and Nampoothiri, 2020 ; Sriwastava et al, 2020 ). The mean latency between infection and GBS symptoms ranged between 11 and 13 days (Sriwastava et al, 2020 ).…”