NCT07418658

Untreated Parkinson's Disease Work-up Assessing Resident Microbiota and Duodenal Barrier Function

Multimodal Characterization of Gastrointestinal Structure, Function, and Microbiome in Drug-Naïve Parkinson's Disease

• Status: Not Yet Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 100 (estimated)
• Sponsor: Universitaire Ziekenhuizen KU Leuven · Academic / Other
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Accepted

Summary

The UPWARD study is a prospective hypothesis-generating study in individuals with untreated Parkinson's disease (PD) and age-matched healthy controls (HCs). The objective of the study is to characterise disease-driven gastrointestinal (GI) changes that occur prior to initiation of treatment. The main questions this study aims to answer are: 1. Are there changes in duodenal permeability in people with untreated PD? 2. Are there changes in the gut microbiome in people with untreated PD? 3. Are these gut changes linked to prodromal features, or movement and non-movement symptoms of PD? The study consists of a screening visit, followed by a six-day home phase and one subsequent study visit at UZ Leuven. During the home phase, participants collect a stool sample, ingest radiopaque markers to assess gut transit time, and complete questionnaires. During the study visit, participants undergo an abdominal X-ray, a clinical assessment, and blood sampling. An upper GI endoscopy with duodenal biopsies is offered as an optional component of the study. This study does not test a therapeutic intervention. Examinations as part of the study are not standard clinical care. The findings are expected to improve understanding of early GI involvement in PD and to inform future mechanistic and clinical research.

Detailed description

This is a hypothesis-generating study aimed at characterising gut microbiome composition and intestinal permeability in patients with drug-naïve Parkinson's disease (PD), compared to age-matched healthy controls (HCs). Drug-naïve PD patients and HCs will be prospectively recruited. After a screening visit, participants will undergo a single study visit; no longitudinal follow-up is planned. Participants will undergo standardized assessments across five domains: (1) gut microbiome and fecal read-outs, (2) duodenal barrier function assessed using optional duodenal biopsies, (3) whole-gut transit time measured with radiopaque markers, (4) clinical features assessed using validated questionnaires and rating scales, and (5) laboratory parameters obtained from blood sampling. For the main study procedures (stool collection, radiopaque pellet ingestion with abdominal X-ray, clinical assessments, questionnaires, and blood sampling), approximately 75 drug-naïve PD patients will be included. Approximately one third are expected to consent to the optional gastroduodenoscopy, resulting in an estimated subgroup of 25 PD patients with duodenal biopsies. Age-matched healthy controls will be recruited in comparable numbers for the respective study components. All analyses will be cross-sectional.

Conditions

• Parkinson's Disease (PD)

Interventions

Type	Name	Description
OTHER	Invasive sampling procedures	Invasive sampling procedures in the study include an (optional) gastroduodenoscopy with duodenal biopsies, and venous blood sampling.
OTHER	Non-invasive sampling procedures	Non-invasive sampling procedures in this study include a clinical examination, radiopaque pellet test with an abdominal X-ray (to assess whole-gut transit time), stool sample collection, and questionnaires.

Timeline

• Start date: 2026-02-01
• Primary completion: 2029-02-01
• Completion: 2029-02-01
• First posted: 2026-02-18
• Last updated: 2026-02-18

Locations

1 site across 1 country: Belgium