Parkinson's Disease (PD)UPWARDNCT07418658
Untreated Parkinson's Disease Work-up Assessing Resident Microbiota and Duodenal Barrier Function
An observational study of Parkinson's Disease (PD), run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Parkinson's Disease (PD)
- What is being tested?
- Invasive sampling procedures and Non-invasive sampling procedures
- How many people
- 100 participants
- Where
- 1 siteBelgium
- Study dates
- Feb 2026to Feb 2029
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Patient participants will be recruited during patient consultations in the Movement Disorders Clinic of UZ Leuven. Neurologists in other hospitals may also be informed about the study, so that they may refer interested patients to UZ Leuven for potential participation in the study.
Who may be able to join
- Patients eligible for inclusion in this study must meet all of the following criteria:
- Diagnosis of Parkinson's Disease by a neurologist according to the Movement Disorder Society Clinical Diagnostic Criteria for PD
- Signed informed consent form
- Aged 18-75 years old
- Able to understand the study and questionnaires, and comply with study requirements
- Controls eligible for inclusion in this study must meet all of the following criteria:
Show all 9Show fewer
- Aged 40-75 years old
- Signed informed consent form
- Able to understand the study and questionnaires, and comply with study requirements
Who cannot join
- Participants eligible for this study must not meet any of the following criteria:
- Patients and controls:
- Gastrointestinal: diagnosis of organic gastrointestinal diseases potentially affecting the assessments during the study (e.g. inflammatory bowel disease (IBD), celiac disease, eosinophilic diseases of the gastro-intestinal tract, gastro-intestinal cancer, diverticulitis in the last 6 months, GI infection in the last 3 months, …).
- Surgery: major abdominal surgery (including, but not limited to: cholecystectomy, colectomy, hiatal hernia repair, …) except for uncomplicated appendectomy, splenectomy and inguinal hernia repair.
- Medication use:
- Any previous exposure to medication used in the treatment of motor symptoms of Parkinson's disease (levodopa, dopamine agonists, MAO-B inhibitors, COMT-inhibitors, NMDA-receptor antagonists, anticholinergics)
Show all 23Show fewer
- Antibiotics use in the last 3 months.
- Use of PPI in the last month.
- Use of NSAID in the last month.
- Use of anticoagulation4 (including vitamin K antagonists (VKA), direct oral anticoagulants (DOAC) or low-molecular weight heparins (LMWH)) or dual antiplatelet therapy4 (DUAPT; Acetylsalicilic acid (Asaflow®) + P2Y12-inhibitor (Clopidogrel®)).
- Pregnancy and breastfeeding.
- Other: Cancer and/or adjuvant treatment within the last 6 months
- Exposures:
- Food intoxication in the last 3 months.
- Consumptom of more than 2 standard units of alcohol per day.
- Patients (additional criteria)
- 1. Neurological: any major neurological disorder other than Parkinson's disease.
- Controls (additional criteria)
- Neurological:
- A diagnosis of Parkinson's disease or any other major neurological disorder other than Parkinson's disease.
- Clinical signs of parkinsonism.
- First degree relative(s) with Parkinson's disease.
- Gastrointestinal: subjects fulfilling a clinical diagnosis of either Functional dyspepsia, Functional constipation, or Irritable bowel syndrome based on the ROME-IV diagnostic criteria.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site
UZ Leuven
Leuven, Vlaams-Brabant, 3000
Bo Konings, MD, +32494433087, bo.konings@uzleuven.be
Wim Vandenberghe, Prof. Dr.
About this study
Official title: Multimodal Characterization of Gastrointestinal Structure, Function, and Microbiome in Drug-Naïve Parkinson's Disease
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:
Read more
- Are there changes in duodenal permeability in people with untreated PD?
- Are there changes in the gut microbiome in people with untreated PD?
- 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.
Read the 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)
- Being tested
- Invasive sampling procedures, Non-invasive sampling procedures
- Keywords
- Gut Microbiome, Intestinal Permeability, Drug-Naïve
- Medical subject headings
- Parkinson Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Invasive sampling proceduresOther
Invasive sampling procedures in the study include an (optional) gastroduodenoscopy with duodenal biopsies, and venous blood sampling.
Non-invasive sampling proceduresOther
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.
| Study group | Role | What they receive |
|---|---|---|
| Drug-Naïve Parkinson's disease patients | Not described Receives: Other: Invasive sampling procedures; Other: Non-invasive sampling procedures | |
| Age-matched healthy controls | Not described Receives: Other: Invasive sampling procedures; Other: Non-invasive sampling procedures |
What is being measured
The primary outcome is the main question the study is designed to answer.
Paracellular flux
After mounting duodenal mucosal biopsies on Ussing chambers, the paracellular permeability is measured by adding a fluorescently labelled dextran to the luminal side and quantifying cumulative paracellular flux to the basolateral side at serial time points.
Measured: On day 7 (Follow-up visit)
Transepithelial electrical resistance (TEER)
After mounting duodenal mucosal biopsies on Ussing chambers, the TEER will be measured by applying an electrical current and recording the resulting change in potential difference (PD).
Measured: On day 7 (Follow-up visit)
Fecal microbiota composition
The fecal microbiota composition will be analysed on fecal samples using techniques including (but not limited to) 16s rRNA sequencing.
Measured: Analyses wil be performed after storage of stool samples, collected during the at-home phase (day 1-6) preceding the Follow-up visit on day 7.
Duodenal microbiota composition
The duodenal microbiota composition will be analysed on duodenal samples obtained by gastroduodenoscopy using techniques including (but not limited to) 16s rRNA sequencing.
Measured: Analyses wil be performed after storage of duodenal samples, collected during the gastroduodenoscopy on day 7 (Follow-up visit).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Feb 2026
- Study startFeb 2026 (estimated)
- Primary completionFeb 2029 (estimated)
- Study completionFeb 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Parkinson's Disease (PD)Studies of the same condition, open and under way.
- More trials run by Universitaire Ziekenhuizen KU LeuvenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universitaire Ziekenhuizen KU Leuven
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07418658
- Sponsor's protocol ID
- s71449
- Acronym
- UPWARD
- Status last verified
- Jan 2026
- First submitted
- 26 Jan 2026
- Last updated
- 18 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 18 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Multimodal Characterization of Gastrointestinal Structure, Function, and Microbiome in Drug-Naïve Parkinson's Disease
- ClinicalTrials.gov ID
- NCT07418658
- Acronym / sponsor ID
- UPWARD / s71449
- Conditions
- Parkinson's Disease (PD)
- Keywords
- Gut Microbiome, Intestinal Permeability, Drug-Naïve
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Universitaire Ziekenhuizen KU LeuvenUniversity, hospital or other
- Study start
- Feb 2026 (estimated)
- Primary completion
- Feb 2029 (estimated)
- Study completion
- Feb 2029 (estimated)
- First posted
- 18 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- Are there changes in duodenal permeability in people with untreated PD?
- Are there changes in the gut microbiome in people with untreated PD?
- 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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Drug-Naïve Parkinson's disease patients | – | Other: Invasive sampling procedures, Other: Non-invasive sampling procedures |
| Age-matched healthy controls | – | Other: Invasive sampling procedures, Other: Non-invasive sampling procedures |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Patient participants will be recruited during patient consultations in the Movement Disorders Clinic of UZ Leuven. Neurologists in other hospitals may also be informed about the study, so that they may refer interested patients to UZ Leuven for potential participation in the study.
Key inclusion criteria (9 listed)
- Diagnosis of Parkinson's Disease by a neurologist according to the Movement Disorder Society Clinical Diagnostic Criteria for PD
- Signed informed consent form
- Aged 18-75 years old
- Able to understand the study and questionnaires, and comply with study requirements
- Aged 40-75 years old
Key exclusion criteria (23 listed)
- Gastrointestinal: diagnosis of organic gastrointestinal diseases potentially affecting the assessments during the study (e.g. inflammatory bowel disease (IBD), celiac disease, eosinophilic diseases of the gastro-intestinal tract, gastro-intestinal cancer, diverticulitis in the last 6 months, GI infection in the last 3 months, …).
- Surgery: major abdominal surgery (including, but not limited to: cholecystectomy, colectomy, hiatal hernia repair, …) except for uncomplicated appendectomy, splenectomy and inguinal hernia repair.
- Medication use:
- Pregnancy and breastfeeding.
- Other: Cancer and/or adjuvant treatment within the last 6 months
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Invasive sampling proceduresInvasive sampling procedures in the study include an (optional) gastroduodenoscopy with duodenal biopsies, and venous blood sampling. | Other | Age-matched healthy controls, Drug-Naïve Parkinson's disease patients |
| Non-invasive sampling proceduresNon-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. | Other | Age-matched healthy controls, Drug-Naïve Parkinson's disease patients |
Primary outcome
Paracellular flux
Time frame: On day 7 (Follow-up visit)
After mounting duodenal mucosal biopsies on Ussing chambers, the paracellular permeability is measured by adding a fluorescently labelled dextran to the luminal side and quantifying cumulative paracellular flux to the basolateral side at serial time points.
Transepithelial electrical resistance (TEER)
Time frame: On day 7 (Follow-up visit)
After mounting duodenal mucosal biopsies on Ussing chambers, the TEER will be measured by applying an electrical current and recording the resulting change in potential difference (PD).
Fecal microbiota composition
Time frame: Analyses wil be performed after storage of stool samples, collected during the at-home phase (day 1-6) preceding the Follow-up visit on day 7.
The fecal microbiota composition will be analysed on fecal samples using techniques including (but not limited to) 16s rRNA sequencing.
Duodenal microbiota composition
Time frame: Analyses wil be performed after storage of duodenal samples, collected during the gastroduodenoscopy on day 7 (Follow-up visit).
The duodenal microbiota composition will be analysed on duodenal samples obtained by gastroduodenoscopy using techniques including (but not limited to) 16s rRNA sequencing.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Parkinson's Disease (PD), run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 23 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 18 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Paracellular flux (time frame: On day 7 (Follow-up visit)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Feb 2026.