Dritan Agalliu, Kiran T. Thakur & Peter D. Canoll - January 20, 2021

Dritan Agalliu, PhD, Associate Professor of Neurology, Pathology and Cell Biology; Kiran T. Thakur, MD, Assistant, Professor of Neurology & Peter D. Canoll, MD, PhD, Professor of Pathology and Cell Biology, Director of Neuropathology, "COVID-19 and the Brain -Lessons from Neuropathological Studies"

Many COVID-19 patients have neurological manifestations, according to the published case reports, such as headaches, impaired consciousness, dizziness, and anosmia. The virus could enter the CNS system through the olfactory sensory axons, the impaired CNS vasculature, and the blood-CSF barrier. Dr. Thakur and Dr. Agalliu’s group focused on the neuropathological evidence of the CNS inflammation, the neurovascular deficit, and the presence of the SARS-CoV2 virus in the COVID-19 brains. Among the cohort of 41 COVID-19 brains, the related neuropathological alteration included focal to global hypoxia (100%), mild lymphocytic infiltrates (93%), focal or diffuse microglial activation (81%), microglial nodules (63%), acute focal hemorrhagic infarcts (20%). However, the vascular basement membrane was minimally abnormal, and CD3 T cell infiltration was relatively low. Using qRT-PCR, the group quantified the viral copy in several brain regions of 26 COVID-19 brains. Compared with the high viral volume in the nasal epithelium, the measurably low volume of the virus was present in the olfactory bulb (40%), temporal lobe (36%), cerebellum (44%), medulla (33%), and superior frontal gyrus (14%). Possibly due to the low viral volume in those brain regions, the probe hybridization and RNAscope failed to detect the viral presence at the same time. In this study, Dr. Agalliu’s group provided substantial neuropathological evidence in the COVID-19 brains, which could be causative factors contributing to patients' neurological manifestation. Also, with the sensitive qRT-PCR technique, a low amount of virus was found in the COVID-19 brains, although the CNS vasculature was minimally impaired.