CHANGES in the spike protein of the coronavirus have been found to enhance its ability to infect the brain, potentially explaining the brain-related symptoms associated with Covid-19, including the "brain fog" seen in long Covid cases, according to a new study.
The spike protein is responsible for guiding the virus, SARS-CoV-2, into human cells, initiating infection. The exact causes of long Covid and its neurological effects remain unclear and are currently under extensive investigation worldwide.
This study, conducted by researchers at Northwestern University in the UK and the University of Illinois-Chicago in the US, could provide insights into these phenomena and pave the way for targeted treatments to protect the brain and eliminate the virus from the central nervous system.
The findings, published in the journal Nature Microbiology, were based on experiments in which mice were infected with the coronavirus. As the virus replicated, researchers compared the spike proteins of viruses found in the brain to those in the lungs.
The results showed that in the lungs, the spike protein closely resembled that of the original infecting virus. However, in the brain, many of the viruses exhibited deletions or mutations in regions of the spike protein crucial for entering human cells.
"Looking at the genomes of viruses found in the brain compared to the lungs, we found that viruses with a specific deletion in spike were much better at infecting the brains of these animals," said Judd Hultquist, an assistant professor of medicine (infectious diseases) at Northwestern University and a corresponding author on the study.
Further, when the viruses having the mutated spike protein travelled to the lungs of the mice, they were found to be weakened.
The researchers, therefore, suggested that these viruses were better able to infect the cells of the brain and the central nervous system. The authors also believe that the spike protein is a "critical regulator of whether or not the virus gets into the brain".
The findings could thus have large implications for the treatment and management of neurological symptoms reported by COVID-19 patients, Hultquist said.
"If (long Covid) is caused by infection of cells in the central nervous system, our study suggests there may be specific treatments that could work better than others in clearing the virus from this compartment," he said. (PTI)
