NCT07786116Recruiting
The Role of METhanogens in the PROgression Of Parkinson's Disease and Related Neurological Conditions
Met-Pro Study: The Role of METhanogens in the PROgression Of Parkinson's Disease and Related Neurological Conditions
Source: ClinicalTrials.gov · Last updated 25 Aug 2026
Brief summary (registry, in English)
Gut problems, such as constipation, can have an important impact on quality of life of people who have them, and have been associated with higher risk of developing neurological diseases such as Parkinson's or Alzheimer's disease. Recent studies suggest that gut problems may also have implications for the progression of these diseases, as constipation is a risk factor for faster Parkinson's and Alzheimer's progression. However, how constipation and brain diseases are linked is unknown. Previous research has suggested that gut changes may lead to inflammation, which could play a role in accelerating the progression of both movement and memory problems in Parkinson's and memory and thinking problems in people with cognitive impairment. Methane is a gas that is naturally produced by microorganisms in the gut. Levels of methane can be measured using a simple breath test. Higher methane levels in the breath are thought to be more common in people with Parkinson's disease (PwP) when compared to people without Parkinson's (healthy controls) and have been associated with gut symptoms, particularly constipation, as well as worse movement problems in PwP, although they are less understood in conditions that affect memory and thinking (like dementia or mild cognitive impairment). The investigators want to better understand the changes in the gut of PwP and people with cognitive impairment (e.g. mild cognitive impairment or dementia). They will compare breath methane levels in PwP, people with cognitive impairment, people with REM Sleep Behaviour Disorder (a sleep condition linked to a higher risk of developing Parkinson's) and healthy participants. Participants will be followed-up over time to assess how methane levels are linked to changes in the blood and the stools, gut function, and clinical symptoms. This study has 2 components: Component 1: observational study, where the study investigators will follow 200 participants over 2 visits, 18 months apart. The study will recruit 4 groups of people: 50 people with Parkinson's disease, 50 people at high risk of developing Parkinson's disease (people with REM Sleep behaviour disorder), 50 people with other conditions affecting cognition (e.g. dementia, mild cognitive impairment), and 50 healthy controls. Component 2: study with 15 people with Parkinson's, who produce high methane levels, to test whether a probiotic (Lactobacillus reuteri) affects how much methane is produced.
- Status (registry)
- Recruiting
- Study type
- Interventional
- Enrollment
- 215 (estimated)
- First submitted
- 8 Jul 2026
- Start date
- 1 Nov 2025
- Primary completion date
- 30 Jun 2027
- Lead sponsor
- University of Cambridge
- Diseases
- Alzheimer disease, Parkinson disease
- NCT number
- NCT07786116
What you commit to
- Study type: Interventional
- Planned participants: 215
- From 1 Nov 2025 to the primary completion date, 30 Jun 2027
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Use of immunosuppressive drugs within the preceding 12 months;
- Use of oral/intravenous steroids within the preceding 3 months;
- Regular use (more than twice per week) of non-steroidal anti-inflammatory drugs (e.g. ibuprofen, naproxen, diclofenac, meloxicam) or over 75mg aspirin;
Other illness
- Presence of other neurological disorder, chronic inflammatory/autoimmune disorder, active cancer, active metabolic disease, diabetes type I and II, and active or latent infection;
- Inability to understand or speak English fluently.
- For participants in Component 2 of the study (Experimental Medicine Study), additional exclusion criteria will be in place, namely, known allergy to any of the probiotic's ingredients: Bulking agent (isomalt), sweetener (xylitol), L. reuteri DSM 17938, strawberry flavouring and flavour enhancer (citric acid).
Other
- Participation in other interventional studies, within the preceding 3 months;
- Consumption of laxatives, stool softeners, stool bulking agents, motility agents, iron supplements and probiotics within the preceding 3 months;
- Current smoker
Who the study is looking for
- People with PD:
- 55 years of age or above;
- MDS criteria for Idiopathic PD;
- H\&Y\<3.
- People at high risk of developing PD (people with REM Sleep behaviour disorders):
- 55 years of age or above;
- RBD diagnosis confirmed by polysomnography.
- Other conditions affecting cognition (e.g. dementia, mild cognitive impairment):
- 55 years of age or above;
- Diagnosis of non-PD dementia or MCI, or, MoCA score ≤25
- Healthy Controls:
- 55 years of age or above
- MoCA total score ≥26.
Age in the registry: 55 years to - · Sex: All · Accepts healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| John Van Geest Centre for Brain Repair - Forvie Site, Robinson Way Coordinator of this site? Confirm its status | Cambridge | United Kingdom | Recruiting |
This page is information, not medical advice. Discuss any trial with your doctor.