Can intestinal infections cause parkinson’s?

Gastrointestinal infections may play a role in the pathogenesis of Parkinson’s disease, according to a study in the Journal of Innate Immunity.


Various studies have shown that the alpha-synuclein (αS) protein, which, when it accumulates in the brain is characteristic of Parkinson’s disease, is produced in the intestine. More specifically, it may be produced in the enteric nervous system (ENS), our “second brain,” which controls the digestive system and appears to use the vagus nerve to connect to brain structures. But its role is still not known.

To identify it, researchers analyzed samples of intestines (biopsies) taken from children with chronic or acute gastrointestinal (GI) disorders and from adults and children who had received intestinal transplants and subsequently contracted viral infections. They discovered that αS is produced in reaction to intestinal infection and that it plays a role in the gastrointestinal tract’s immune defense.

Previous studies have shown that in patients with a certain genetic profile, an increase in αS is sufficient to cause Parkinson’s disease. Moreover, a comparable increase in αS exists during repeat GI infections caused by certain microbes.

In this study, researchers suggest that patients with Parkinson’s may have increased intestinal permeability for microbes that promote the excessive production and deposit of αS in the intestine and later the brain. Parkinson’s disease, therefore, may start in the ENS, in the intestine, and result from an abnormal response to an infection, which leads to the excess production of αS--an originally benign component of the immune system in our second brain.


Stolzenberg et al. A Role for Neuronal Alpha-Synuclein in Gastrointestinal Immunity. J Innate Immun, 2017. DOI: 10.1159/000477990