GBPDC: Gut-Brain in PD Consortium Master Protocol
Start Date
7/3/2026
Completion Date
12/31/2028
Summary
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).
Detailed Description
The objectives of the master protocol are to establish a common platform that: (1) assures the collection, integration, and analysis of a set of uniformly collected data across all participating centers, and (2) follows the objective of the Gut-Brain Parkinson's Disease Consortium (GBPDC) with the goal "to enhance our understanding of the temporal onset of GI symptoms in PD and changes in gut-brain communication that can be used to leverage the potential role of the GI tract in the pathogenesis and progression of PD and to improve patient diagnosis, care, and outcomes." Primary Objective 1\. To collect prospective cross-sectional and longitudinal participant biospecimens with temporally coordinated evaluations of GI and neurological symptoms and functions to better characterize the phenotype of people with PD versus those without. Secondary Objectives 1. To elucidate the biological processes and pathways relevant to the role of the GI tract in the pathogenesis and progression of PD. 2. To characterize GI symptoms, pathology, and gut-brain communication in PD to detect early and longitudinal changes in gut function and activity that correspond to the development or progression of PD. Exploratory Objectives 1. To identify possible novel gut-based biomarkers (functional, molecular, etc.), diagnostic tools, and therapeutic targets. 2. To investigate the impact of neuroimmune interactions and other pathways in the GI tract on gut-brain communication and PD risk. In conjunction with clinical, social, and environmental characterization, biospecimen collection within the GBPDC master protocol will provide the opportunity to probe and characterize the pathophysiologic underpinnings of the gut-brain axis in PD, refine existing biomarker testing for PD, and identify new biomarkers that could allow early detection of PD or new targets for treatment. Duke University will serve as the biorepository for the GBPDC. Participants and study site personnel will collect, process, and ship biospecimens according to the GBPDC Biorepository Manual of Procedures using standard kits assembled specifically for the GBPDC master protocol. Biospecimens will be shipped from the study sites to the GBPDC central biorepository at Duke University for accessioning, storage, tracking, and subsequent distribution for use in approved future research. Throughout the conduct of the master protocol, a portion of the biospecimens received by the GBPDC central biorepository will be transferred to the NIDDK biorepository for approved research use. Any biospecimen aliquots remaining at the GBPDC central biorepository at the termination of the GBPDC program will be transferred to the NIDDK biorepository. Statistical Design This is a prospective, observational, longitudinal cohort study designed to characterize gut-brain communication in Parkinson's Disease. The study employs a longitudinal design, including cross-sectional analyses of baseline data, to evaluate gastrointestinal and neurological functions in participants with PD compared to household controls and a prodromal cohort, as well as comparisons among PD severity subgroups. Study Design Features: * Multi-center observational study across 5 GNRCs * Three participant cohorts: people with PD, people with prodromal features of PD, and household controls. The PD cohort will be further classified as mild, moderate, or severe PD. * Longitudinal design with assessments at baseline, 6, 12, 18, and 24 months * Comprehensive biospecimen collection coordinated with clinical assessments * Household control design where controls are matched to people with PD when available
Eligibility Criteria
Age Range: 21 years to 80 years
Conditions
Locations
Stanford University
Stanford, California 94305
United States
Rush University
Chicago, Illinois 60612
United States
University of Chicago
Chicago, Illinois 60637
United States
Massachusetts General Hospital
Boston, Massachusetts 02114
United States
Mayo Clinic
Rochester, Minnesota 55905
United States
Columbia University
New York, New York 10027
United States
Medical University of South Carolina
Charleston, South Carolina 29425
United States