Oral Bacteria and Parkinson's Disease

Researchers have identified a potential link between a common oral bacterium called Streptococcus mutans, well known for causing cavities and Parkinson’s disease. In a study of stool samples from hundreds of people, scientists found that S. mutans was more abundant in the gut microbiomes of individuals with Parkinson’s disease compared with those without it.

This bacterium can produce an enzyme called urocanate reductase, which creates a chemical called imidazole propionate; this compound appears capable of entering the bloodstream and reaching the brain, where it may contribute to the damage of dopamine producing neurons, a hallmark of Parkinson’s disease. In mouse experiments, introducing bacteria that produce this enzyme led to increased levels of the metabolite in blood and brain tissue, loss of dopamine neurons, increased neuroinflammation, motor difficulties, and build-up of alpha-synuclein, a protein associated with Parkinson’s pathology.

While this research doesn’t yet prove that oral bacteria cause Parkinson’s in humans, it highlights a newly discovered oral–gut–brain pathway that could play a role in disease development and may offer future avenues for prevention or treatment by targeting oral and gut microbes.

Source: Pathway between oral bacteria Parkinsons disease identified | American Dental Association