People who have suffered Covid-19 could be living with a "silent killer" say experts. Researchers have discovered a reaction to the virus which has no symptoms but which can be slowly killing off a vital part of the brain.
This can put some people more at risk of brain disorders such as Parkinson's and Alzheimers. However they say as well as it revealing a potential future risk for those who have had the virus it could also offer a possible treatment.
The team, led by The University of Queensland, carried out tests on the brain's immune cells - "microglia". They discovered the virus activates the same inflammatory response in the brain as Parkinson’s disease.
The team was led by Professor Trent Woodruff and Dr Eduardo Albornoz Balmaceda from UQ’s School of Biomedical Sciences, and virologists from the School of Chemistry and Molecular Biosciences. Prof Woodruff said: “Our team grew human microglia in the laboratory and infected the cells with SARS-CoV-2, the virus that causes Covid-19.
“We found the cells effectively became ‘angry’, activating the same pathway that Parkinson’s and Alzheimer’s proteins can activate in disease, the inflammasomes.”
Dr Albornoz Balmaceda said triggering the inflammasome pathway sparked a ‘fire’ in the brain. This then begins a chronic and sustained process of killing off neurons - the 'information messengers' of the brain which send messages around the brain and the nervous system.
He said: “It’s kind of a silent killer, because you don’t see any outward symptoms for many years. It may explain why some people who’ve had Covid-19 are more vulnerable to developing neurological symptoms similar to Parkinson’s disease.”
The researchers found the spike protein of the virus was enough to start the process. It was further exacerbated when there were already proteins in the brain linked to Parkinson’s.
Prof Woodruff said: “So if someone is already pre-disposed to Parkinson’s, having Covid-19 could be like pouring more fuel on that ‘fire’ in the brain. The same would apply for a predisposition for Alzheimer’s and other dementias that have been linked to inflammasomes.”
But the study also found a potential treatment. The researchers administered a class of UQ-developed inhibitory drugs which are currently in clinical trials with Parkinson’s patients.
“We found it successfully blocked the inflammatory pathway activated by Covid-19, essentially putting out the fire,” Dr Albornoz Balmaceda said. “The drug reduced inflammation in both Covid-19-infected mice and the microglia cells from humans, suggesting a possible treatment approach to prevent neurodegeneration in the future.”
Professor Woodruff said while the similarity between how Covid-19 and dementia diseases affect the brain was concerning, it also meant a possible treatment was already in existence. He said: “Further research is needed, but this is potentially a new approach to treating a virus that could otherwise have untold long-term health ramifications.”
The research was co-led by Dr Alberto Amarilla Ortiz and Associate Professor Daniel Watterson and involved 33 co-authors across UQ and internationally. The study is published in Nature’s Molecular Psychiatry.
