GBPDC: Gut-Brain in PD Consortium Master Protocol

NCT07567794 | Not Yet Recruiting

• 7 other identifiers: Pro001158115U24DK140918-025U01DK140933-025U01DK140923-025U01DK140921-025U01DK140936-025U01DK140939-02
• Study Type: observational
• Target: 250
• Locations: 1 country
• Sites: 7

Brief 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).

Conditions

Parkinson Disease (PD); PARKINSON DISEASE (Disorder); Gut Microbiome; Gut Microbiota; Prodromal Parkinsons Disease

Keywords

gut brain; Parkinson's disease; Prodromal Parkinson's disease; healthy control

Outcome Measures

Primary Outcomes (2)

• GI influences on PD

  Trait and State cross-sectional evaluation of GI influences on PD

  enrollment to end of observation at 24 months

• Co-associations components of the GBA

  Cross-sectional co-associations components of the GBA

  enrollment to end of observation at 24 months

Other Outcomes (2)

• GBA Disruption and Parkinson's disease Progression

  enrollment to end of observation at 24 months

• GBA Disruption and Prodromal Participants

  enrollment to end of observation at 24 months

Study Arms (3)

Household Controls

Age-similar household controls. Household control design where controls are matched to people with PD when available.

People with Parkinson's disease

The Parkinson's Disease (PD) cohort will be further classified as mild, moderate, or severe PD as classified by Hoehn and Yahr scale.

Prodromal Parkinson's disease

People with Parkinson's Disease prodromal features. Prodromal characteristics are defined by the MDS Research Criteria for PD and include either polysomnography (PSG)-confirmed rapid eye movement sleep behavior disorder (RBD) or possible RBD (questionnaire-based), with hyposmia as defined by the University of Pennsylvania Smell Identification Test (UPSIT) ≤ 15th percentile.

Eligibility Criteria

• Age: 21 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients at the NIDDK designated Gastroenterology Neurology Research Centers

You may qualify if:

• 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
• Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures
• Resides within the same household as person with PD
• Aged ≥21 years old and ≤80 years old
• Prodromal characteristics are defined by the MDS Research Criteria for PD and include either polysomnography (PSG)-confirmed rapid eye movement sleep behavior disorder (RBD) or possible RBD (questionnaire-based), with hyposmia as defined by the University of Pennsylvania Smell Identification Test (UPSIT) ≤ 15th percentile.

You may not qualify if:

• 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
• Clinically significant cognitive impairment with a Montreal Cognitive Assessment (MOCA) score \<22
• Clinical or laboratory findings consistent with another primary neurodegenerative disease or cognitive disorder other than PD, including but not limited to, frontotemporal lobar disease, Huntington's disease, progressive supranuclear palsy, multisystem atrophy, Creutzfeld-Jakob- Disease, Down's syndrome, cortico-basal degeneration, dementia with Lewy Bodies, Alzheimer's disease, amyotrophic lateral sclerosis, seizure disorder, stroke, or other infectious, metabolic, or systemic disease affecting the central nervous system including, but not limited to, syphilis, present hypothyroidism, present or unaddressed/treated vitamin B12 deficiency, or other screening laboratory abnormalities
• Suicidality, defined as active suicidal thoughts or ideation within 6 months before Screening or at Baseline, defined as answering yes to items 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS), or history of suicide attempt in previous 2 years, or, in the Investigator's opinion, at serious risk of suicide
• Has cancer or has had a malignant tumor within the past 5 years. (Participants with stable untreated prostate cancer or treated/removed cutaneous carcinomas are not excluded.)
• Any medical condition or systemic disease that, in the Investigator's opinion, may either put the participant at risk because of participation in the study, influence the results or proposed analyses, or impair the participant's ability to fully participate in the study
• Body mass index (BMI) \>35 kg/m2 or body weight \<50 kg
• Participant is currently pregnant, breastfeeding, and/or lactating
• History of alcohol or substance abuse or dependence within the past 2 years (DSM IV criteria)

Sponsors & Collaborators

• Duke University: lead
• Massachusetts General Hospital: collaborator
• Stanford University: collaborator
• Medical University of South Carolina: collaborator
• Columbia University: collaborator
• Mayo Clinic: collaborator
• Rush University Medical Center: collaborator
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): collaborator
• University of Chicago: collaborator

Study Sites (7)

Stanford University

Stanford, California, 94305, United States

Location

Rush University

Chicago, Illinois, 60612, United States

Location

University of Chicago

Chicago, Illinois, 60637, United States

Location

Massachusetts General Hospital

Boston, Massachusetts, 02114, United States

Location

Mayo Clinic

Rochester, Minnesota, 55905, United States

Location

Columbia University

New York, New York, 10027, United States

Location

Medical University of South Carolina

Charleston, South Carolina, 29425, United States

Location

Related Links

• Related Info

Biospecimen

Retention: SAMPLES WITH DNA

Venous blood will be collected and stored as whole blood for later DNA and/or RNA isolation and processed for plasma, buffy coat, peripheral blood mononuclear cells, and serum for use in approved future research. Stool specimens will be used to support qualitative and quantitative microbiome analyses and other discovery research. Unstimulated saliva will be collected for microbiome analyses and the alpha synuclein seeding amplification assay. Both skin and gastrointestinal mucosal biopsy specimens will be obtained for future use, including, but not limited to, pathologic examination and assays for alpha synuclein.

MeSH Terms

Conditions

Parkinson Disease

Condition Hierarchy (Ancestors)

Parkinsonian Disorders; Basal Ganglia Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Movement Disorders; Synucleinopathies; Neurodegenerative Diseases

Study Officials

• Lisa Wruck

  Duke Clinical Research Institute

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 29, 2026
• First Posted: May 5, 2026
• Study Start (Estimated): June 4, 2026
• Primary Completion (Estimated): December 31, 2028
• Study Completion (Estimated): December 31, 2028
• Last Updated: May 5, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share

Locations

US (7)