The purpose of this research study is to identify the role that the gut-brain axis, the group of nerves that connect the brain and gut, plays in Parkinson's disease (PD). The National Institute of Diabetes and Digestive and Kidney Diseases is sponsoring this research study.
During this study, specific groups of participants, also known as "cohorts", will be identified based on the severity of their PD. There will also be a cohort enrolling participants who do not have Parkinson's and a cohort enrolling participants that are at risk for developing PD. Each of these cohorts will be compared to the others to assess the differences in the gut-brain connection.
Participants in this study will:
* meet with a medical provider
* answer questionnaires
* give samples of blood, stool, and saliva
* have X-rays taken while swallowing different foods (swallowing study)
* have X-rays taken to see how long it takes markers to move through their colon (colon transit study)
* have a flexible sigmoidoscopy, where a doctor looks inside the lower part of the colon and takes small tissue samples (biopsies) from the mucosa (lining)
* have samples taken of their skin
* have an anorectal manometry and a balloon expulsion test, where a small tube and balloon are placed in the rectum to measure muscle function.
Participation in the study will last up to 24 months (2 years).
Who can participate
Age range
21 Years – 80 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Aged ≥21 years old and ≤80 years old
. Clinical diagnosis of PD as defined by Movement Disorder Society (MDS) PD Criteria
. Adequate visual, hearing, cognitive, and physical ability
. Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures. Because longitudinal participation is important to the scientific goals of the program, a "best estimate" of interest, commitment, and geographic feasibility for three years will be documented by the enrolling investigator after interview with the potential enrollee
. Aged ≥21 years old and ≤80 years old
. No known or diagnosed neurodegenerative disease
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1This study is looking at how the gut microbiome and gut-brain connection relate to Parkinson's disease — does my current stage of PD, or whether I'm still in a prodromal phase, affect whether this kind of research is something worth discussing for me?
2Since this trial is listed as Phase NA, it sounds like it may be more of an observational or data-collection study rather than a treatment trial — can you explain what that means for me practically, and whether participating would change anything about my current care?
3The study mentions looking at GBA co-associations — can you explain whether my genetic background, like whether I carry a GBA variant, might be especially relevant to what this research is trying to learn?
4Given that this trial is focused on understanding gut influences on PD rather than testing a new therapy, what would I actually need to do as a participant, and how time-intensive or logistically demanding might that be for someone in my situation?
5Are there other studies or standard treatment paths I should consider alongside or instead of this one, especially if I'm hoping to find options that might more directly address my symptoms in the near term?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
GI influences on PD
Timeframe: enrollment to end of observation at 24 months
2
Co-associations components of the GBA
Timeframe: enrollment to end of observation at 24 months
. Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures
. Resides within the same household as person with PD
Exclusion criteria
. Diagnosis of secondary or atypical parkinsonism
. Laboratory Values:
. Hemoglobin (Hgb) \<10
. Platelets \<70,000
. Alanine Transaminase (ALT) or Aspartate Aminotransferase (AST) \> 2 1/2 times upper limit of normal (ULN)
. Moderate or severe renal disease with an estimated glomerular filtration rate (eGFR) \<60 mL/min/BSA \[body surface area\]) calculated using the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, or moderate or severe hepatic impairment (alkaline phosphatase \[ALP\] \>2.0 times the ULN and/or total bilirubin \>2.0 times the ULN)
. Significantly above the normal range for PT/INR/PTT
. Currently taking anticoagulants that are deemed exclusionary by the investigator for risk of bleeding with sigmoidoscopy procedure