A growing body of evidence is challenging the traditional understanding of Parkinson's disease as a purely brain-based disorder. A recent study adds to this growing body of evidence by suggesting that the disease may originate in the gastrointestinal tract, The Washington Post reported.
Gastrointestinal problems are commonly associated with Parkinson's disease, often appearing years before motor symptoms. These issues include constipation, drooling, trouble swallowing, and delayed stomach emptying. In fact, a condition known as "institutional colon" was once linked to individuals living in mental health institutions due to the prevalence of gastrointestinal problems among patients with neurodegenerative disorders.
“People have, for the longest time, described Parkinson's disease as a top-down disease — so, it starts in the brain and then percolates down to the gut, and that's why patients have issues with their gastrointestinal tract,” said study author Subhash Kulkarni, an assistant professor at Beth Israel Deaconess Medical Center. “Another hypothesis suggests that, in many patients, it may be a bottom-up approach, where it starts in the gut and goes all the way up to the brain.”
The study, published in JAMA Network Open, examined the medical records of over 9,000 patients who underwent upper endoscopies between 2000 and 2005. Researchers found that individuals with mucosal damage in their upper gastrointestinal tract were significantly more likely to develop Parkinson's disease later in life. This damage often occurred years before the onset of motor symptoms.
“We absolutely need to keep an eye on these patients who have a history of mucosal damage on their endoscopy,” said Delaram Safarpour, an associate professor of neurology at Oregon Health & Science University, who was not involved in the research. Early detection of Parkinson's disease would allow doctors to treat these patients before they have motor symptoms, when neuroprotective treatments become available in the future, Safarpour said.
The results provided further support for the 'gut-first' hypothesis of Parkinson's disease. Ted M. Dawson, a professor of neurodegenerative diseases at Johns Hopkins University School of Medicine said that when the gut-first hypothesis "first came out, there was a lot of skepticism in the field. But the evidence has been accumulating, and this study is another step in the stairway to acceptance that the gut is a major pathway by which Parkinson's can occur.”
The findings of this study have important implications for the early detection and treatment of Parkinson's disease. By identifying individuals at risk based on gastrointestinal symptoms, doctors may be able to intervene earlier and potentially delay or prevent the onset of motor symptoms.
