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NCT Number: NCT07286968

Gastro-Intestinal Digestion and Physiology After Bariatric Surgery

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.

Recruiting

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Key information

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Universitaire Ziekenhuizen KU Leuven

Leuven, 3000, Netherlands

Location status: Recruiting

Location contact

Maaike De Kreek, MSc

CONTACT

[email protected]

+32 16 34 72 89

About this study

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).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

  • Voluntary written informed consent of the participant has been obtained prior to any screening procedures
  • Age: 18-65 years

Specific inclusion criteria for the different patient populations:

Patients with obesity:

  • Body Mass Index: > 30 kg/m2

Patients after bariatric surgery:

  • 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:

  • Patient has history of more than one bariatric surgery
  • Patient has a waist circumference > 125.6 cm
  • Patient had gastrointestinal surgery in the past three months
  • Patient has a pacemaker, defibrillator, infusion pump, or other portable or implanted electromedical device
  • Patient had frequent exposure to X-rays in the past year
  • Patient has swallowing disorders, among others: dysphagia for food or pills, any oropharyngeal or oesophageal stricture, anxiety or functional abnormality
  • Patient has Crohn's disease or Diverticulitis
  • Patient has gastrointestinal strictures, fistulas or physiological/mechanical obstructions
  • Patient has gastric bezoar
  • Patient has a history of complex bowel resection or known abdominal adhesions
  • Patient has short bowel syndrome or ostomy
  • Patient has currently ongoing infections
  • Patient is planned to undergo usage of rectal foam/enema or treatment with adjuvant chemotherapy or radiotherapy
  • Patient is currently on parenteral diet
  • Patient is planned to undergo MRI procedure during usage of the wireless capsule
  • 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
  • Patient is pregnant, breastfeeding, actively trying to get pregnant or had recent childbirth in last 6 months
  • 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.
  • Any disorder, which in the investigator's opinion might jeopardise participant's safety or compliance with the CIP.

Treatment and study plan

Gastro-intestinal aspiration

Other

Aspiration of fluids from the stomach and small intestine using a naso-intestinal catheter.

Telemetric

Device

Telemetric ingestible capsule

Primary outcomes

  1. Activity of gastric lipase

    Time frame: 2 hours

    Gastric pouch and sleeve samples will be analysed for gastric lipase activity (described in U)

  2. Activity of pepsin

    Time frame: 2 hours

    Gastric pouch and sleeve samples will be analysed for pepsin activity (described in U)

  3. 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).

  4. 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).

  5. 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).

  6. 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).

Secondary outcomes

  1. Concentration of total bile acids

    Time frame: 2 hours

    The total bile acid concentrations will be measured in all samples

  2. pH

    Time frame: 2 hours

    pH will be measured in all gastro-intestinal samples

  3. Total transit time

    Time frame: 48 hours

    Total transit time will be measured by the GISMO GEN I ingestible sensor (described in minutes).

  4. Gastric emptying time

    Time frame: 48 hours

    Gastric emptying time will be measured by the GISMO GEN I ingestible sensor (described in minutes).

  5. 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).

  6. 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).

Study contacts

Contact information is provided by the study sponsor or research team.

Bart Van der Schueren, Prof. Dr.

CONTACT

Maaike De Kreek, MSc

CONTACT

[email protected]

+32 16 34 72 89

Sponsors and collaborators

Lead sponsor

Universitaire Ziekenhuizen KU Leuven

Other

Registry information

Acronym: GIBa

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Dec 16, 2025
Registry last updated
Jan 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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