Gastro-Intestinal Digestion and Physiology After Bariatric Surgery (GIBa)

January 15, 2026 updated by: Universitaire Ziekenhuizen KU Leuven
The goal of this clinical trial is to characterize gastrointestinal digestion and physiology in patients after bariatric surgery, or people living with obesity. The main question it aims to answer is: what is the status of gastrointestinal digestion and physiology after bariatric surgery? Participants will have two study visits: 1) participants will undergo collection of gastrointestinal samples and 2) participants will ingest an ingestible capsule that measures multiple physiological parameters along the gastrointestinal tract.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This clinical trial aims to characterize gastric and pancreatic enzyme activity in adults aged 18 to 65 who have previously (at least 1 year ago) undergone Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG), as well as in individuals with obesity. In addition, the study seeks to quantify bile acid concentrations and pH at various locations within the gastrointestinal tract and to assess gastrointestinal transit time. During the study, aspirates will be collected from multiple regions of the gastrointestinal tract using a naso-intestinal catheter (study visit 1). An ingestible capsule will also be used to obtain continuous in vivo measurements of physiological conditions along the entire gastrointestinal tract (study visit 2).

Study Type

Observational

Enrollment (Estimated)

51

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Bart Van der Schueren, Prof. Dr.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients who have previously undergone a RYGB surgery, SG surgery, or people with obesity.

Description

Inclusion Criteria:

Participants eligible for inclusion in this Investigation have to meet all of the following criteria:

  1. Voluntary written informed consent of the participant has been obtained prior to any screening procedures

  2. Age: 18-65 years

    Specific inclusion criteria for the different patient populations:

    Patients with obesity:

  3. Body Mass Index: > 30 kg/m2

    Patients after bariatric surgery:

  4. Surgery: at least one year after Roux-en-Y gastric bypass or sleeve gastrectomy

Exclusion Criteria:

Participants eligible for this Investigation must not meet any of the following criteria:

  1. Patient has history of more than one bariatric surgery
  2. Patient has a waist circumference > 125.6 cm
  3. Patient had gastrointestinal surgery in the past three months
  4. Patient has a pacemaker, defibrillator, infusion pump, or other portable or implanted electromedical device
  5. Patient had frequent exposure to X-rays in the past year
  6. Patient has swallowing disorders, among others: dysphagia for food or pills, any oropharyngeal or oesophageal stricture, anxiety or functional abnormality
  7. Patient has Crohn's disease or Diverticulitis
  8. Patient has gastrointestinal strictures, fistulas or physiological/mechanical obstructions
  9. Patient has gastric bezoar
  10. Patient has a history of complex bowel resection or known abdominal adhesions
  11. Patient has short bowel syndrome or ostomy
  12. Patient has currently ongoing infections
  13. Patient is planned to undergo usage of rectal foam/enema or treatment with adjuvant chemotherapy or radiotherapy
  14. Patient is currently on parenteral diet
  15. Patient is planned to undergo MRI procedure during usage of the wireless capsule
  16. Patient is working in a professional healthcare facility (e.g. hospital, dental office, emergency room), military area (e.g. submarine, near radar installation), or heavy industrial area (e.g. power plants, automotive, mining, refineries) during the duration of the clinical investigation
  17. Patient is pregnant, breastfeeding, actively trying to get pregnant or had recent childbirth in last 6 months
  18. Patient cannot discontinue medication that affects gastrointestinal transit time and/or pH for at least 3 days before and during the study (and 4 weeks for weekly/long-acting GLP-1 analogues such as Saxenda, Ozempic, Wegovy, Mounjaro). This includes opioids (e.g., morphine, codeine), proton pump inhibitors (e.g., omeprazole, esomeprazole, pantoprazole), H2-receptor antagonists (e.g., cimetidine, famotidine), antacids, sucralfate, prokinetics (e.g., domperidone, metoclopramide), antidiarrheal agents (e.g., loperamide), antibiotics, probiotics and prebiotics.
  19. Any disorder, which in the investigator's opinion might jeopardise participant's safety or compliance with the CIP.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Roux-en-Y gastric bypass
Patients who had undergone Roux-en-Y gastric bypass surgery
Other: Gastro-intestinal aspiration
Aspiration of fluids from the stomach and small intestine using a naso-intestinal catheter.
Device: Telemetric
Telemetric ingestible capsule
Sleeve gastrectomy
Patients who had undergone sleeve gastrectomy surgery
Other: Gastro-intestinal aspiration
Aspiration of fluids from the stomach and small intestine using a naso-intestinal catheter.
Device: Telemetric
Telemetric ingestible capsule
Patients living with obesity
Patients without previous bariatric surgery
Other: Gastro-intestinal aspiration
Aspiration of fluids from the stomach and small intestine using a naso-intestinal catheter.
Device: Telemetric
Telemetric ingestible capsule

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Activity of gastric lipase
Time Frame: 2 hours
Gastric pouch and sleeve samples will be analysed for gastric lipase activity (described in U)
2 hours
Activity of pepsin
Time Frame: 2 hours
Gastric pouch and sleeve samples will be analysed for pepsin activity (described in U)
2 hours
Activity of trypsin
Time Frame: 2 hours
Samples collected in the duodenum and jejunum; or roux- and common-limb will be analysed for trypsin activity (described in U).
2 hours
Activity of chymotrypsin
Time Frame: 2 hours
Samples collected in the duodenum and jejunum; or roux- and common-limb will be analysed for chymotrypsin activity (described in U).
2 hours
Activity of α-amylase
Time Frame: 2 hours
Samples collected in the duodenum and jejunum; or roux- and common-limb will be analysed for α-amylase activity (described in U).
2 hours
Activity of pancreatic lipase
Time Frame: 2 hours
Samples collected in the duodenum and jejunum; or roux- and common-limb will be analysed for pancreatic lipase activity (described in U).
2 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Concentration of total bile acids
Time Frame: 2 hours
The total bile acid concentrations will be measured in all samples
2 hours
pH
Time Frame: 2 hours
pH will be measured in all gastro-intestinal samples
2 hours
Total transit time
Time Frame: 48 hours
Total transit time will be measured by the GISMO GEN I ingestible sensor (described in minutes).
48 hours
Gastric emptying time
Time Frame: 48 hours
Gastric emptying time will be measured by the GISMO GEN I ingestible sensor (described in minutes).
48 hours
Small intestinal transit time
Time Frame: 48 hours
Small intestinal transit time will be measured by the GISMO GEN I ingestible sensor (described in minutes).
48 hours
Large intestinal transit time
Time Frame: 48 hours
Large intestinal transit time will be measured by the GISMO GEN I ingestible sensor (described in minutes).
48 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Universitaire Ziekenhuizen KU Leuven

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 10, 2026

Primary Completion (Estimated)

July 1, 2027

Study Completion (Estimated)

July 1, 2027

Study Registration Dates

First Submitted

December 3, 2025

First Submitted That Met QC Criteria

December 3, 2025

First Posted (Estimated)

December 16, 2025

Study Record Updates

Last Update Posted (Actual)

January 20, 2026

Last Update Submitted That Met QC Criteria

January 15, 2026

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • S70844
  • CIV-25-08-054154 (Other Identifier: AFMPS - FAGG)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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