There is a connection between the intestine and the brain –known as the gut-brain axis– which helps explain why an imbalance in the intestinal microbiota –a group of microorganisms (bacteria, viruses, fungi, protozoa…) that inhabit the intestine– may influence the development of mental disorders. Now, a new study has confirmed that certain intestinal problems are linked to an increased risk of Parkinson’s.
It is believed that before a cerebrovascular disease appears, such as a stroke, a brain aneurysm, or even Alzheimer’s, gastrointestinal symptoms appear, and it has been suggested (Braak’s hypothesis) that gastrointestinal alterations could also precede Parkinson’s disease. . To verify the veracity of this hypothesis, the authors of the new work have compared 24,624 people who suffered from Parkinson’s of unknown cause with those who had been diagnosed with a neurological disorder, such as Alzheimer’s (19,046) or a cerebrovascular accident (23,942).
The results of their analysis have revealed that up to four intestinal disorders were associated with an increased risk of a Parkinson’s diagnosis. Specifically, gastroparesis (delayed movement of food from the stomach to the small intestine), dysphagia (difficulty swallowing), and constipation were associated with a doubled risk of Parkinson’s disease in the five years prior to diagnosis. In the case of irritable bowel syndrome (IBS) without diarrhea, it was associated with a 17% increased risk. The findings have been published in the journal Gut.
“The intestine could be a primary target for understanding intestinal dysfunction in Parkinson’s disease, in order to find drug targets”
The researchers found that other intestinal problems, such as functional dyspepsia, irritable bowel syndrome (IBS) with diarrhea, and diarrhea with fecal incontinence, were also more common among people who developed Parkinson’s disease. Inflammatory bowel disease and vagotomy were not associated with increased risk, while removal of the appendix appears to play a protective role.
Gastrointestinal disorders that could predict Parkinson’s
The study is observational, so the authors have indicated that they cannot establish a cause, in addition to acknowledging certain limitations, such as too short a follow-up or that the information on which they have been based could be incomplete. However, they state that this is the first study to provide observational evidence that “dysphagia, gastroparesis, IBS without diarrhea, and constipation may specifically predict Parkinson’s disease,” potentially leading to earlier detection and new insights. potential treatments.
The professor of Membrane Physiology and Biology at the University of California at David (United States) Kim Barrett has told SMC Spain that “it has long been understood that the brain communicates with the intestine and some have hypothesized that factors coming from the intestine could trigger the development of neurological conditions, such as Parkinson’s disease (PD). The article in the journal Gut makes an important contribution by showing that some GI diagnoses are linked to a subsequent diagnosis of PD, suggesting that it may be important for clinicians to take note of these GI conditions when evaluating patients at risk for PD, even before the onset of neurological symptoms.
In the opinion of Tim Bartels, group leader at the UK Dementia Research Institute at UCL: “The study strongly establishes an association between specific forms of bowel dysfunction (constipation, gastroparesis and dysphagia) preceding the development of motor symptoms that they are typically used to diagnose clinical Parkinson’s disease. Since the disease has usually already progressed to large-scale neurodegeneration in the substantia nigra of patients presenting with motor symptoms, any earlier clinical signs and possible biomarkers would be of great value for earlier (and thus more extensive) treatment. effective) and for the targeting of medicines”, according to his statements to SMC Spain.
“An additional interesting point from the study is the apparently protective association of appendectomy with Parkinson’s disease, which further implies that, within the gastrointestinal system, the appendix could be the source of the disease attack that then spreads throughout the intestine and ultimately to the brain. Since the latter association was within the range of possible surveillance bias, this needs to be further validated,” he adds.
And he concludes that: “the association found here, therefore, firmly establishes that the intestine could be a main target to look for biomarkers in humans or to develop better model systems to understand intestinal dysfunction in Parkinson’s disease, in order to to find drug targets.
