Covid-19 could accelerate Parkinson’s disease

Adding fuel to the fire of neurodegenerative diseases? Covid affects a large number of organs, including the brain. The neurological problems they are also very common among people suffering from long-term Covid. Several studies have shown that coronavirus infection cause of inflammation in the brain, followed by an increase in neuronal mortality. This inflammation is mainly triggered by microhemorrhages that asphyxiate brain cells, but the virus itself could directly participate in this inflammation. Australian researchers from the University of Queensland have shown that SARS-CoV-2 activates immune cells in the brain and thus causes an inflammatory state. This process is amplified in people with Parkinson’s disease, which could accelerate the development of this neurodegenerative disease. Their discovery was published Nov. 1, 2022 in the journal Molecular psychiatry.

The coronavirus activates an inflammatory process in the brain

Brain scans of people who died from Covid had already revealed inflammation of brain tissue and hyperactivation of microglial cells. These cells are macrophages that are activated when the innate immune response is triggered, which occurs especially during an infection. Once activated, microglial cells produce a protein (NLRP3). This protein forms the inflammasome, a molecule that triggers an inflammatory cascade that ultimately leads to cell death in infected cells. But if this activation continues over time, it can lead to chronic inflammation.

The researchers studied the activation of these microglial cells in mice expressing the human ACE2 receptor, used by the coronavirus to enter cells. Hyperactivation of these immune cells and increased production of NLRP3 were observed in the brain after infection. Education in vitro he then demonstrated that the coronavirus manages to infect these macrophages, but fails to replicate in these cells. The microglial cells would then be activated directly by the virus, detecting its presence thanks to the infection. And since the virus can’t replicate there, these cells wouldn’t be in danger.

Neurological inflammation is aggravated by α-synuclein

The coronavirus then directly triggers the production of the inflammasome and the resulting inflammatory state, similar to that observed in some neurodegenerative diseases. “This could explain why people who have had Covid are more likely to develop symptoms similar to those of Parkinson’s disease“says Eduardo Albornoz Balmaceda, author of the study, in a communicated.

Worse yet: this inflammatory process is amplified when infection occurs in the presence of α-synuclein, a protein that accumulates in Parkinson’s disease. “For someone predisposed to this pathology (and which therefore already has an accumulation of α-synuclein, ed)having Covid-19 could be like adding fuel to the fire that threatens his brainadds Trent Woodruff, director of research. The same could be true for predispositions to Alzheimer’s disease or other diseases related to these inflammasomes.“