Constipation in Early Parkinson’s Disease is Linked to Neuroinflammation
Constipation can be a very early non-motor symptom of Parkinson’s disease (PD) often appearing long before motor symptoms. A new study published in Movement Disorders on November 13, 2025, investigated the potential link between constipation and early PD development. The new study entitled “Constipation is Linked to Neuroinflammation in Early Parkinson’s Disease” looked at specific signs of neuroinflammation in people with early PD who also have constipation.
Twenty-seven people with early PD were assessed with brain imaging, bloodwork and cerebrospinal fluid testing of neuroinflammatory biomarkers. These measurements were correlated with scores on the Gastrointestinal Dysfunction Scale for Parkinson’s Disease (GIDS-PD). The research found that those with constipation displayed significantly greater evidence of inflammation in the central nervous system than those without. This means that the same inflammatory processes suspected of contributing to nerve cell degeneration in PD might also contribute to gut symptoms very early in the disease process.
This new study supports the idea that inflammatory changes may begin long before motor symptoms are evident, potentially linking early non-motor signs like constipation to core disease mechanisms.
Implications
The idea that PD may begin outside the brain, and particularly in the gut is not new. Understanding the link between gut symptoms and neuroinflammation can have important implications. For example, biomarkers of neuroinflammation could become part of diagnostic testing of early disease or could be used as indicators of whether clinical trials are effective in early disease. Also, therapies aimed at reducing inflammation or modifying the gut-brain interaction could be explored as ways to slow or prevent progression of PD.
Next Steps
The authors note that while the connection between constipation and inflammation is clear in the group tested, more work is needed to understand the specific pathways involved and whether these findings apply broadly across diverse patient populations. Regardless, this study suggests that a better understanding of what causes gut symptoms in PD can improve our understanding of the development of PD in general.
Explore these APDA-funded research projects that are investigating the role of the gut and neuro-inflammation in PD:
- Letizia Zanetti, PhD: Investigating the role of the immune system in juvenile, genetic Parkinsonism
- Laura Cox, PhD: Understanding how bacteria in the digestive system contributes to developing and/or worsening of PD
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