A study by more than 70 Brazilian researchers indicates that the new coronavirus can affect the brain and cause the death of neurons, even in people who have mild symptoms and who have not needed hospital treatment.
The research, published on Tuesday on the medRxiv scientific platform, but which is still under evaluation, indicates that the virus can promote significant changes in the structure of the cortex, the brain region richest in neurons and responsible for complex functions such as memory, attention, consciousness and language.
“Patients with Covid-19 may have neuropsychiatric and / or neurological symptoms. We found that anxiety and cognitive impairment are manifested by 28-56% of individuals infected with SARS-CoV-2 with mild respiratory symptoms or without respiratory symptoms and are associated with altered cerebral cortical thickness ”, points out the study, coordinated by researchers from the State University Campinas (Unicamp) and the University of São Paulo (USP).
The investigation also found brain damage in 19% of individuals who died from Covid-19 and were under analysis.
According to researchers, when the new coronavirus enters the brain attacks cells responsible for metabolic processes, hampering the production of energy and nutrition of neurons and may consequently lead to the death of brain tissue.
All affected brain tissues exhibited foci of infection by SARS-CoV-2, particularly in astrocytes [células mais abundantes do sistema nervoso central]. The infection of astrocytes derived from neural stem cells altered energy metabolism, altered key proteins and metabolites used to feed neurons (…) and triggered a secretory phenotype that reduces neuronal viability ”.
“Our data support the model in which SARS-CoV-2 reaches the brain, infects astrocytes and triggers neuropathological changes that contribute to structural and functional changes in the brain of patients with Covid-19 ″, emphasizes the document published in medRxiv.
Speaking to the G1 news portal, Clarissa Lin Yasuda, one of the study’s coordinators, stated that they found many patients who, even already cured from Covid-19 about two months ago, they continued to show neurological symptoms, such as severe headaches, excessive sleepiness, altered memory, in addition to loss of smell and taste.
“In some rare cases, even seizures, and these patients had never felt this before ”, stressed the researcher.
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The study also points to evidence that the access route to the brain is through the nose.
The investigation analyzed magnetic resonance images in mild patients, who had not yet needed hospitalization, which demonstrated a significant reduction in the cerebral cortex in some regions close to the airways, in the so-called orbitofrontal region, proving that these are changes in the brain structure.
Clarissa Lin Yasuda also stated that there are suspicions that the virus may activate genetic diseases such as schizophrenia, Parkinson’s and Alzheimer’s.
“What we we still don’t know is the severity of these injuries, if they are transient or if they can be irreversible, so we will monitor these patients for the next three years to find out if the virus triggers degenerative diseases in those who have some genetic potential ”, explained the researcher to G1.
Brazil is the Portuguese-speaking country most affected by the pandemic and one of the hardest hit in the world, when counting the second number of deaths (more than 5.1 million cases and 151,747 deaths), after the United States.
The Covid-19 pandemic has already claimed more than one million and eighty-seven thousand deaths and more than 38.2 million cases of infection worldwide, according to a report made by the French agency AFP.
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