Parkinson remains a mystery for science and an ordeal for the sick. But this discovery opens an astonishing track: the oral-intestinal microbiome could become a new target to prevent or slow down this pathology.
When Parkinson invites himself into daily life
Parkinson’s disease strikes approximately one to two people in a hundred after 65 years. Tremors, muscle rigidity, slowness of gestures, digestive disorders or loss of smell are the best known signs. These symptoms have grown over the years, transforming the daily life of patients and their entourage. Today, treatments such as L-DOPa reduce certain disorders but do not slow down the degeneration of neurons producing dopamine.
In recent years, researchers have been interested in the role of the intestinal microbiota, this universe of bacteria nestled in our bowels. Several studies have shown clear differences between patients and healthy people, but without managing to explain how these microbes could contribute to the disease. The new study conducted at Postch in South Korea brings an element of response by designating an unexpected culprit: a bacteria from the mouth.
Experiences that connect the mouth to the brain
Under the direction of Professor Ara Koh, the Korean team observed that Streptococcus mutans was more present in the intestine of Parkinson patients. This bacteria has an enzyme, called Reductase Urocanate, which manufactures a molecule called imidazole propionate. The researchers found this compound not only in the intestine, but also in the blood and the brain of the patients.
By setting up the bacteria in the mouse intestine without microbiota, they saw a disturbing cascade appear: accumulation of the toxic molecule, loss of dopaminergic neurons, brain inflammation, alpha-synuclein aggregation and motor disorders close to those observed in patients. When they blocked the MTORC1 signaling route with treatment, these symptoms have significantly reduced.
As Professor Ara Koh explains: “Our study provides a mechanistic understanding of how oral microbes present in the intestine can influence the brain and contribute to the development of Parkinson’s disease“. She adds:
“”This highlights the potential to target the intestinal microbiota as the therapeutic strategy, offering a new direction for the treatment of Parkinson“.
These results are added to other works showing that bacteria in the mouth could worsen Parkinson animal models when they colonize the intestine. In humans, analyzes of the oral and intestinal microbiome confirm that S. MUTANS is often more abundant in patients. Oral health could thus weigh on the evolution of this neurological disease.
Towards a new approach to prevent Parkinson
These discoveries open new hopes, even if many questions remain unanswered. Imagine that Parkinson’s prevention can go through a better mastery of the oral-intestinal microbiota upsets the perspectives. Treat the presence of S. MUTANS In the mouth or intestine, act on the MTORC1 route with molecules already known in medicine, or monitor the presence of the toxic molecule in the blood as an early marker, all this could become possible strategies.
However, we must remain cautious: the most convincing experiences have been carried out on mice and not yet in humans. Researchers will also have to ensure that the elimination of the bacteria does not cause adverse effects, because the microbiome is a fragile balance. Finally, not all forms of parkinson are not based on this single mechanism.
But the idea that the link between the mouth, the intestine and the brain can be decisive to understand and treat Parkinson is a real novelty. If it is confirmed, this track could transform the daily life of patients and change the way medicine envisages one of the most dreaded neurological diseases.
Without delay, these new research highlights the importance of good dental hygiene for aesthetics but also for cardiovascular health, brain health …