The "silent killer" – COVID-19 affects the brain in a similar way to dementia

The brains of mice infected with COVID-19 showed "angry" microglia in green and SARS-CoV-2 in red
.

Researchers say the COVID-19 virus affects the brain in a similar
way to dementia.
A study led by the University of Queensland (UQ) in Australia found that COVID-19-activated brain inflammation is the same
as Parkinson's disease.
This finding not only identifies the potential risk of developing neurodegenerative diseases in patients with COVID-19 in the future, but also suggests a possible treatment
.

The University of Queensland research team was led
by Professor Trent Woodruff and Dr Eduardo Albornoz Balmaceda from the University of Queensland's School of Biomedical Sciences and virologists from the School of Chemical and Molecular Biosciences.

Professor Woodruff said: "We looked at the effect of the virus on brain immune cells, known as 'microglia', which are key cells
involved in the progression of brain diseases such as Parkinson's and Alzheimer's.
Our team grew human microglia in the lab and infected the cells
with the SARS-CoV-2 virus that causes COVID-19.
We found that these cells actually become 'angry', activating the same pathway that Parkinson's and Alzheimer's proteins activate in disease – the inflammasome
.
" ”

Dr.
Balmaceda says that triggering the inflammasome pathway triggers a "fire" in the brain, starting a chronic and sustained process
of killing neurons.

Dr Balmaceda said: "It's a silent killer because you don't see any outward symptoms
for years.
This may explain why some people infected with COVID-19 are more likely to experience neurological symptoms
similar to Parkinson's disease.
”

The researchers found that the virus's spike protein was sufficient to initiate this process, which was further exacerbated
when Parkinson's-related proteins were already present in the brain.

Professor Woodruff said: "So if someone already has a predisposition to Parkinson's, contracting COVID-19 may be like pouring more fuel
on a 'fire' in the brain.
The same applies to susceptibility to Alzheimer's disease and other dementias associated with inflammasomes
.
”

But the study also found a potential treatment
.
The researchers used a class of inhibitory drugs that are currently in clinical trials in
Parkinson's patients.

Dr Balmaceda said: "We found that it successfully blocked the inflammatory pathways activated by COVID-19, essentially extinguishing the fire
.
The drug reduced inflammation in mice infected with COVID-19 and microglia from humans, suggesting that a future could be a treatment
to prevent neurodegeneration.
”

Professor Woodruff said that while the similarities between COVID-19 and the effects of dementia on the brain were worrying, it also meant that a possible treatment already existed
.

"Further research is needed, but this could be a new way to treat the virus that could otherwise have immeasurable long-term health effects
.
"

The study, co-led by Dr Alberto Amarilla Ortiz and Associate Professor Daniel Watterson, involved 33 co-authors from the University of Queensland and internationally
.

The study was published Nov.
1 in
the journal Molecular Psychiatry.

Reference: "SARS-CoV-2 drives NLRP3 inflammasome activation in human microglia through spike protein" by Eduardo A.
Albornoz, Alberto A.
Amarilla, Naphak Modhiran, Sandra Parker, Xaria X.
Li, Danushka K.
Wijesundara, Julio Aguado, Adriana Pliego Zamora, Christopher L.
D.
McMillan, Benjamin Liang, Nias Y.
G.
Peng, Julian D.
J.
Sng, Fatema Tuj Saima, Jenny N.
Fung, John D.
Lee, Devina Paramitha, Rhys Parry, Michael S.
Avumegah, Ariel Isaacs, Martin W.
Lo, Zaray Miranda-Chacon, Daniella Bradshaw, Constanza Salinas-Rebolledo, Niwanthi W.
Rajapakse, Ernst J.
Wolvetang, Trent P.
Munro, Alejandro Rojas-Fernandez, Paul R.
Young, Katryn J.
Stacey, Alexander A.
Khromykh, Keith J.
Chappell, Daniel Watterson and Trent M.
Woodruff, 1 November 2022, Molecular Psychiatry.