COVID-19 infection may accelerate brain ageing, long-term neurodegenerative diseases in elderly: Study

COVID-19 infections may predispose individuals to developing irreversible neurological conditions, according to a study. The finding, published in the journal Ageing Research Reviews, also shows that COVID-19 may increase the likelihood of strokes and the chance of developing persistent lesions that can lead to brain bleeding.

The team, led by Joy Mitra and Muralidhar L. Hegde, from the Houston Methodist Research Institute, US, noted that a great deal of research has shown that the impacts of COVID-19 go far beyond the actual time of infection.

COVID-19 is known to invade and infect the brain, among other major organs, the researchers said. The coronavirus infection can cause long-term and irreversible neurodegenerative diseases, particularly in the elderly and other vulnerable populations, they said.

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Several brain imaging studies on COVID-19 victims and survivors have confirmed the formation of microbleed lesions in deeper brain regions related to our cognitive and memory functions.

Researchers have critically evaluated the possible chronic neuropathological outcomes in aging and comorbid populations if timely therapeutic intervention is not implemented.

Microbleeds are emerging neuropathological signatures frequently identified in people suffering from chronic stress, depressive disorders, diabetes and age-associated comorbidities.

Based on their earlier findings, the researchers noted that COVID-19-induced micro-haemorrhagic lesions may exacerbate DNA damage in affected brain cells, resulting in neuronal senescence and activation of cell death mechanisms, which ultimately impact brain microstructure-vasculature.

These pathological phenomena resemble hallmarks of neurodegenerative conditions like Alzheimer's and Parkinson's diseases and are likely to aggravate advanced-stage dementia, as well as cognitive and motor deficits.

The effects of COVID-19 infection on various aspects of the central nervous system are currently being studied, the researchers said.

For instance, 20-30 per cent of COVID-19 patients report a lingering psychological condition known as "brain fog" where individuals suffer from symptoms such as memory loss, difficulty in concentrating, forgetting daily activities, difficulty in selecting the right words, taking longer than usual time to complete a regular task, disoriented thought processes and emotional numbness.

More severe long-term effects analysed in the review include predispositions for Alzheimer's, Parkinson's and related neurodegenerative diseases, as well as cardiovascular disorders due to internal bleeding and blood clotting-induced lesions in the part of the brain that regulates our respiratory system, following the COVID-19 symptoms.

Cellular aging is also thought to be accelerated in COVID-19 patients, the researchers said.

A plethora of cellular stresses inhibit the virus-infected cells from undergoing their normal biological functions and let them enter into "hibernation mode" or even die completely, they said.

The study also suggests various strategies to improve some of these long-term neuropsychiatric and neurodegenerative outcomes, as well as outlines the importance of the therapeutic regimen of the "nanozyme" in combination with various FDA-approved drugs that may prove successful to fight against this catastrophic disease.

However, given the ever-evolving nature of this field, associations like the ones described in this review show the fight against COVID-19 is far from over, the researchers said, adding that getting vaccinated and maintaining proper hygiene are key in trying to prevent such long-term and detrimental consequences.