(ORDO NEWS) — A severe form of COVID-19 causes dramatic aging in the human brain, according to a post-mortem analysis of 54 healthy and infected people. The authors of the study say their study is the first to link COVID-19 to the molecular signatures of brain aging.
“We observed that gene expression in the brain tissues of patients who died from COVID-19 closely resembled gene expression in uninfected people aged 71 and older,” says public health scientist Jonathan Lee of Harvard University.
The sample, consisting of people aged twenty to eighty years, included 21 people who had a severe form of COVID-19, one asymptomatic person and 22 people who were not infected with coronavirus.
The researchers also compared their results with an uninfected person with Alzheimer’s disease and another group of 9 uninfected people with a history of hospitalization or treatment on a ventilator.
Using RNA sequencing technology in prefrontal cortex samples, the scientists found that people with severe COVID-19 showed enriched genetic expression patterns associated with aging.
The brains of those infected looked more like those of older controls, regardless of their actual age.
Simply put, genes that are normally up-regulated with aging, such as those associated with the immune system, were also up-regulated with severe COVID-19.
At the same time, genes that decline with aging, such as those associated with synaptic activity, cognition and memory, also declined with severe COVID-19.
“We also observed significant associations of cellular response to DNA damage, mitochondrial function, regulation of stress response and oxidative stress, vesicular transport, calcium homeostasis, and insulin signaling/secretion pathways previously associated with aging and brain aging,” the authors write.
“Overall, our analysis suggests that many of the biological pathways that change with natural brain aging also change with severe COVID-19.”
Ever since the novel coronavirus SARS-CoV-2 began to infect humans on a global scale, scientists have been concerned about the possible long-term consequences.
Brain damage is one of the most problematic consequences. Severe cases of COVID-19 are often associated with brain fog, memory loss, stroke, delirium, or coma. In October 2020, the first brain scans of COVID-19 patients revealed troubling signs of neurological impairment and disorders.
More recent research has shown that even a mild form of COVID-19 can affect the brain, although it is still unclear how long these changes can last and how they compare to severe COVID-19.
Every year, health experts have a better understanding of the long-term consequences of this global pandemic. Three years later, things don’t look good.
The results of the current study follow those of another study published earlier this year, which found that the cognitive consequences of severe COVID-19 are equivalent to about 20 years of aging.
Neuropathologist Marianne Bougiani of the University of Amsterdam told Nature that the new findings open “many questions that are important not only for understanding the disease, but also for preparing society for what the consequences of a pandemic could be.”
She also added that these implications may not be clear for many more years. By then, the global community will likely be suffering from repeated cases of COVID-19.
Who knows how multiple diseases will affect our cognitive abilities in the long run?
Interestingly, in the current study, scientists have found no genetic evidence of the SARS-CoV-2 virus in the brains of infected patients, suggesting that the neurological effects of the virus may not be directly related to its presence in the nervous system.
The authors, however, found evidence that tumor necrosis factor (TNF), which is associated with inflammation, brain aging and aging-induced cognitive decline, was present at higher levels in the brains of infected people.
Genetic factors associated with the antiviral immune response were also elevated.
The authors state that both of these pathways “could lead to significant debilitating effects in the brain in the absence of SARS-CoV-2 neuroinvasion.”
In light of their findings, the writing team says that people recovering from COVID-19 should undergo a neurological examination. If the mere presence of this new virus is enough to cause inflammation in the brain, then it is possible that any infected person is at risk of worsening brain conditions.
Until experts know more, the authors say doctors and patients should focus on other risk factors for dementia that are under our control, such as weight, alcohol use and exercise.
Avoiding COVID-19 infection in the future to the best of your ability is also probably a good idea.
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