"The human gut and oral bacterial communities are increasingly linked to neurodegenerative diseases. Disruptions in the gut-brain axis could trigger inflammation and immune responses that contribute to neuronal damage. A common gum disease bacterium like Porphyromonas gingivalis, has been discovered as a potential driver of Alzheimer's," said study author, Dr Saeed Shoaie, group leader of the Quantitative Systems Biology (QTS) Lab at King's College London, in a press release.
For the study, the researchers collected and analyzed 228 samples of stool and saliva from patients with Parkinson's disease who had either mild cognitive impairment or dementia and healthy controls without Parkinon's disease.
Ultimately, they found that the guts of those with cognitive impairment contained more harmful bacteria, many of which likely originated in the mouth and transferred to the gut via a process called 'oral-gut translocation'. The bacteria were found to release virulence factors, which are toxins that can damage gut tissue, promote inflammation, and possibly affect the brain.
Further analysis using artificial intelligence revealed a link between these toxins and cognitive decline in Parkinson's. First author of the study, Dr. Frederick Clasen, a research associate at the QTS lab at King's College London, said in a press release that the toxins could serve as biological markers to identify patients at a higher risk of dementia in Parkinson's. He added that they may also serve as targets for new treatments in the future.
"The emerging evidence underscores the potential importance of maintaining oral and gut health in mitigating or slowing neurodegenerative processes. As people with Parkinson's become increasingly reliant on carers, routine practices such as oral hygiene and nutritional intake may be neglected," said Dr. Shoaie.
"Our findings suggest that promoting a healthy microbiome through consistent oral care, a balanced diet, and potentially targeted probiotic interventions could support improved disease management in Parkinson's," he concluded.
Sources: EurekAlert, Gut Microbes
