People prone to stomach bugs and diarrhea may also have a higher risk of Parkinson's disease, a new study suggests.
Researchers at Georgetown University Medical Center have found that a key protein associated with the neurodegenerative disease is also released during infections in the gastrointestinal tract.
The team said the finding suggests regular bouts of stomach infections or diarrhea could increase your risk of developing Parkinson's.
Researchers at Georgetown University have found that a key protein associated with the neurodegenerative disease is also released during infections in the gastrointestinal tract
The research builds on previous studies that showed patients with Parkinson's had a buildup of a protein called alpha-Synuclein, and that this protein stemmed from the intestines.
Animal studies have also shown that gut microbes can infect the nervous system, which can then travel up to the brain.
This study was conducted on biopsy samples from 42 children with upper gastrointestinal distress, and also 14 adults who had undergone an intestinal transplant and suffered Norovirus.
The biopsies were taken from all parts of the upper GI tract - the esophagus, stomach and duodenum.
In the child group, they saw that those with higher levels of alpha-Synuclein had more severe inflammation of their intestinal walls.
Senior investigator Michael Zasloff, professor of surgery and pediatrics at Georgetown says the new findings 'make sense' of observations made in Parkinson's disease patients.
It is common to suffer chronic constipation from damage to the gut's nervous system, which develops decades before brain symptoms become apparent.
Chronic upper GI distress is also relatively common in people who develop Parkinson's.
However, the protein isn't all bad. In fact, it is the most important protein when it comes to fighting GI infections. Only when there is a chronic build-up does it become dangerous.
'When expressed in normal amounts following an infection of the upper GI tract, αS (alpha-Synuclein) is a good molecule. It is protective,' Prof Zasloff explains.
'The nervous system within the wall of the GI tract detects the presence of a pathogen and responds by releasing αS. αS then attracts white blood cells to the site where it has been released.'
The protein is particularly powerful because it can spread to other nerves very quickly, thereby protecting a large field.
It means the nervous system can protect both itself as well as the GI tract as a whole as soon as the infection is detected.
However, he said, his team's findings show this powerful protein can also be dangerous.
'Too much αS - such as from multiple or chronic infections - becomes toxic because the system that disposes of αS is overwhelmed, nerves are damaged by the toxic aggregates that form and chronic inflammation ensues,' he explains.
'Damage occurs both within the nervous system of the GI tract and the brain.'
The publication of this study, which was released on Tuesday, coincides with the start of a clinical trial targeting the accumulation of alpha-Synuclein in the gut's nervous system.
The early-stage study is examining the safety of an oral drug, ENT-01, a natural steroid produced by dogfish sharks, to relieve constipation associated with Parkinson's disease.