While many people infected with Covid-19 complain of “brain fog” sometimes months after the first symptoms appear, it appears for the first time that SARS-CoV-2 kills certain essential brain cells .
- Since the start of the anti-coronavirus vaccination campaign in France, 49,673,768 people now have a complete vaccination schedule (i.e. 73.7% of the total population).
- The very sharp decline in the number of Covid-19 cases observed since the summer is now over.
According to a new studyCovid-19 leads to the death of endothelial cells in the brain, which would give rise to the appearance of “ghost ships”.
As part of an international collaboration, researchers from Inserm, the Institut Pasteur de Lille and the CNRS have identified for the first time a direct effect of SARS-CoV-2 on the blood vessels of the brain. These results, which are the subject of a publication in the journal Nature Neuroscience, shed light in particular on the long-term consequences of Covid-19.
Vascular endothelial cells
Blood vessels are made up of endothelial cells. Among them, the vascular endothelial cells of the brain make up the blood-brain barrier (BBB). The main function of the BBB is to isolate the central nervous system from the bloodstream, thus preventing foreign substances or potentially toxic molecules from entering the brain and spinal cord, while allowing the transfer of nutrients essential for their activity. . “Participating in this effort, the vascular endothelial cells of the brain therefore play a key role in the proper blood supply to the brain and their survival is essential for its proper functioning”, explain the researchers in the preamble.
empty tubes
Through preclinical study models and the study of the cortex of patients who died from SARS-CoV-2 infection, scientists have shown that this pathology leads to the death of endothelial cells in the brain, which gives rise at the appearance of “ghost ships” in the brain (i.e. empty tubes, without endothelial cells). As a result, these essential cells could no longer perform their function at the level of the blood-brain barrier.
How does this endothelial cell death occur and what are the mechanisms involved? The team discovered that SARS-CoV-2 causes the endothelial cells it infects to manufacture molecular scissors from its own genetic material. These scissors will cut a protein called NEMO, essential for the survival of endothelial cells which will therefore die.
The consequences of endothelial cell death
According to scientists, the death of vascular endothelial cells in the brain can lead to two major consequences:
– a temporary rupture of the blood-brain barrier causing microhaemorrhages in areas where blood is not supposed to have free access.
– A decrease in blood flow that can lead to the death of patients in the most serious cases.
Cognitive disorders, neurodegenerative disorders, dementias
In addition, scientists are wondering about the long-term consequences of this phase of vulnerability during which the brain of patients is less irrigated. According to them, even if this hypothesis remains to be verified, this window of time could predispose some people who have contracted the disease to develop cognitive, neurodegenerative disorders, or even dementia.
“This awareness of the seriousness of SARS-CoV2 infection and its consequences for the proper functioning of our brain is essential to allow the best possible care of patients who have been infected in the years to come”, concludes Vincent Prévot, research director at Inserm.
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