“The prospect of COVID19-induced brain damage has become a primary concern in cases of ‘long COVID,’ but human neurons in culture are not susceptible to infection. Prior publications suggest that the cells that make the spinal fluid could become infected with SARS-CoV-2, but other routes of entry seemed likely,” said senior author Joseph Gleeson.
‘SARS-CoV-2 can infect pericytes and multiply within them. From there, the viruses disseminate among astrocytes and impact the neuronal system.’
The Neurovascular unit is engaged in regulating cerebral blood flow and blood-brain barrier function. It consists of many specialized cells, including pericytes, astrocytes, and neurons.
Three-Dimensional Brain Model
Pericytes that wrap around blood vessels of the brain contain the SARS-CoV2 receptor. Taking this in mind, researchers from the University of California, San Diego introduced these cells into 3D-brain cell cultures and created a complex model of the neurovascular unit of the human brain.
Then they observed the effects of SARS-CoV-2 on this model. SARS-CoV-2 was virulent enough to infect pericytes and multiply within them. These pericytes disseminated among astrocytes and exploited them as the hub of secondary infection.
Alternative Pathway
“Alternatively, the infected pericytes could lead to inflammation of the blood vessels, followed by clotting, stroke or hemorrhages, complications that are observed in many patients with SARS-CoV-2 who are hospitalized in intensive care units,” added Gleeson.
Although the research revealed potential invasion of SARS-CoV-2 into the human CNS, other evidence showed that most neural cells have little to no capacity for SARS-CoV-2 infection. Yet, the research provides a robust model to study the effects of novel coronavirus on the neuronal network.
Source: Medindia
