At the start of the pandemic, Ayman ElAli was surprised to find that COVID-19 often created neurological problems. The Université Laval biologist, who specializes in cerebrovascular accidents (CVA), has just elucidated one of the mechanisms of these cognitive impairments due to SARS-CoV-2, the coronavirus responsible for COVID-19.
“The protein S of SARS-CoV-2 induces a radical change in the functional cells of the blood vessels of the brain, which protect these vessels,” explains ElAli, who is the lead author of a study published this week in the review Neurobiology of Disease. “There is inflammation of these cells and they become dysfunctional. ”
The S protein is the famous “spicule” (spike) which allows the coronavirus to infect human cells. It has affinities with the cells of the lung, but also of the nasal cavity, which communicates with the brain. It is this S protein that is targeted by current vaccines.
Functional cells affected by protein S, called “pericytes”, surround blood vessels. They regulate the flow in these vessels and modulate the inflammatory response. They are also susceptible to attack by the S protein.
The discovery makes it possible to consider localized treatments that would prevent SARS-CoV-2 from binding to cells in the nasal cavity, to protect the brain.
“We have inhibitors of human cells targeted by the coronavirus, which we could use in a localized manner,” says ElAli.
The vascular neurological problems that the biologist and his team in Quebec are studying are only one of the causes of the cognitive effects of COVID-19.
And the effect of protein S on blood vessels in the brain probably doesn’t explain all of the vascular neurological effects of COVID-19, he warns. These vascular neurological disorders include memory problems, confusion and, in rarer cases, stroke.
What is the next step ? “We worked on human cells in test tubes,” says ElAli. We now need an animal model to reproduce our results. And only after that, we can think of trying treatments. ”
Cognitive impairment in figures
43% to 67% of patients hospitalized for COVID-19 have temporary cognitive impairment.
Source : Frontiers in Psychiatry