ORAL BACTERIA LINKED TO PARKINSON’S DISEASE THROUGH THE GUT–BRAIN AXIS: EVIDENCE OF STREPTOCOCCUS MUTANS METABOLITES AFFECTING NEURAL FUNCTION
DOI:
https://doi.org/10.56238/arev7n11-199Keywords:
Parkinson’s Disease, Streptococcus Mutans, Gut–Brain Axis, Oral Microbiota, Neuronal Function, Imidazole PropionateAbstract
Objective: This narrative review aims to analyze current evidence linking oral bacteria, particularly Streptococcus mutans, to Parkinson’s disease (PD) through the gut–brain axis (GBA). The focus is on microbial colonization of the intestine, metabolite production, and the mechanisms by which these metabolites influence neural function.
Methodology: A comprehensive search of PubMed, Scopus, Web of Science, and Google Scholar was conducted using the keywords “Streptococcus mutans,” “Parkinson’s disease,” “gut–brain axis,” “oral microbiota,” and “neuronal dysfunction.” Both in vivo and in vitro studies published in English between 2015 and 2025 were included.
Results: Evidence indicates that S. mutans can migrate to the intestine, producing urocanate reductase (UrdA) and its metabolite imidazole propionate (ImP), which enter systemic circulation and reach the brain. Animal models demonstrated that these metabolites contribute to dopaminergic neuron loss, neuroinflammation, motor dysfunction, and α-synuclein aggregation. The effects were mediated via activation of the mTORC1 signaling pathway, and pharmacological inhibition of mTORC1 mitigated neurodegenerative changes.
Conclusion: Oral bacteria, particularly S. mutans, may play a critical role in PD pathogenesis via the GBA. Targeting gut microbial composition and metabolite production represents a promising therapeutic avenue. The findings emphasize the potential importance of oral health in preventing or mitigating neurodegenerative disorders.
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References
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