Gut infection could trigger Parkinson's disease, new study claims

A new study claims a gut infection could cause a similar pathology of Parkinson's disease (PD). Researchers came to this conclusion after experimenting with a mouse model. The study was conducted by a team of researchers from Université de Montréal,Montreal Neurological Institute, and McGill University.

Experts say the number of Parkinson's disease cases has been on the rise since 1990 and shows no signs of stopping. By 2050, there could be over 12 million patients around the world.

Mutations in genes coding for proteins like PINK1 and Parkin are the reason for 10 per cent of cases Parkinson's disease. People with these types of mutations are more likely to develop Parkinson's at an early age. "Most of the current models of PD are based on the belief that neurons die due to toxic elements accumulating inside them," study author Louis-Eric Trudeau, who is a neuroscientist, told a news portal. Adding, "This does not explain, however, the fact that PD pathology is initiated in patients several years before the emergence of the motor impairment and any noticeable loss of neurons."

For the study, young mice who did not have a gene linked to the disease were infected with Gram-negative bacteria. This triggered similar symptoms of the condition. The team found a common drug used to treat Parkinson's disease could temporarily reverse the health issue. In a statement, researchers said "in normal mice, the immune system responded properly to the gut infection. But in mice lacking PINK1, the immune system overreacted and triggered autoimmunity, suggesting that rather than dying from toxin accumulation, the killing of dopaminergic neurons involves immune cells. In the infected mutant mice, autoreactive toxic T lymphocytes were shown to be present in the brain and able to attack healthy neurons in culture dishes."

The team further explained, "These data support the idea that PINK1 is a repressor of the immune system, and provide a pathophysiological model in which intestinal infection acts as a triggering event in Parkinson’s disease, highlighting the relevance of the gut–brain axis in the disease."

Based on the findings, the team are hopeful scientists could develop better treatment options."My hope is that this research will advance our understanding of how the human gut microbiome contributes to the onset of Parkinson's," UMass Lowell Public Health Assistant Assistant Proffessor Natalia Palacios told a news portal.

The study's findings were originally published in Nature.



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