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Obesity (BMI>30)FABP4-RYGBNCT07774208

FABP4 Response After Roux-en-Y Gastric Bypass

An observational study of Obesity (BMI>30) and Obesity (BMI > 35), run by Istanbul University.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This retrospective observational cohort study examined serum fatty acid-binding protein 4 (FABP4) dynamics in 28 adults who underwent Roux-en-Y gastric bypass (RYGB), followed at baseline, 3 months, and 6 months. Read more about this study

Who is it for?
Ages 18 to 65 years
How many people
28 participants
Where
No sites listed yet
Study dates
22 Apr 2013to 10 Feb 2015
Phase
Observational
Are there results?
None posted in the registry

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 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: Adults undergoing Roux-en-Y gastric bypass (RYGB) performed by a single surgeon at Istanbul University, Istanbul Faculty of Medicine. The cohort comprised 16 patients previously enrolled in the control (probiotic-only) arm of a completed randomized trial (NCT03517345) and 12 additional consecutive patients undergoing RYGB by the same surgeon during a comparable period who were not enrolled in that trial. Patients using GLP-1 receptor agonists or insulin at any study time point were excluded.

Who may be able to join

  • Adults who underwent Roux-en-Y gastric bypass (RYGB), performed by a single surgeon
  • Completed baseline, 3-month, and 6-month clinical and anthropometric assessments

Who cannot join

  • Use of GLP-1 receptor agonists at any study time point
  • Use of insulin at any study time point
  • Missing 6-month FABP4 measurement (excluded from FABP4-based longitudinal/group analyses; n=1)

About this study

Official title: Heterogeneous Fatty Acid-Binding Protein 4 (FABP4) Responses After Roux-en-Y Gastric Bypass: A Retrospective Observational Cohort Study of Adipokine Remodeling Dissociated From Weight Loss, Inflammation, and Incretin Dynamics

This retrospective observational cohort study examined serum fatty acid-binding protein 4 (FABP4) dynamics in 28 adults who underwent Roux-en-Y gastric bypass (RYGB), followed at baseline, 3 months, and 6 months. Anthropometric, metabolic, and inflammatory parameters were assessed alongside FABP4, fasting GLP-1, and PYY. Patients were classified as FABP4 responders (decrease from baseline to 6 months) or rebound/non-responders. The study investigated whether FABP4 trajectory after RYGB is associated with the magnitude of weight loss, systemic inflammation, and fasting incretin change.

Read the detailed description

Sixteen of the 28 participants had previously been enrolled in the control (probiotic-only, non-prebiotic) arm of a completed, registered randomized trial of pre-/probiotic supplementation after RYGB at the same institution (ClinicalTrials.gov Identifier: NCT03517345); these participants received no prebiotic intervention. The remaining 12 participants underwent RYGB by the same surgeon during a comparable period and were not enrolled in that trial. Blood samples from both subgroups had originally been collected and stored at -80°C as part of their respective prospective clinical follow-up. FABP4 concentrations were subsequently measured in these banked, single freeze-thaw samples using a commercial ELISA assay, blinded to patients' weight-loss and inflammatory outcomes, and merged with the anthropometric and biochemical data collected at the corresponding original visits. Because FABP4 assay and the present statistical analysis were performed after clinical follow-up had already been completed for both subgroups, this study is registered retrospectively.

Keywords
FABP4, Roux-en-Y gastric bypass, adipokine, bariatric surgery, weight loss, adipose tissue remodeling, GLP-1, PYY, inflammation
Medical subject headings
Obesity, Insulin Resistance, Weight Loss, Inflammation

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT07774208
Study groupRoleWhat they receive
Group/Cohort Label: FABP4 RespondersDescription: Patients with a decrease in serum FABP4 from baseline to 6 months after Roux-en-Y gastric bypass (n=9)
Group/Cohort Label: FABP4 Rebound/Non-respondersDescription: Patients with no decrease or an increase in serum FABP4 from baseline to 6 months after Roux-en-Y gastric bypass (n=18)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Measure: Change in serum FABP4 level from baseline to 6 months after RYGB

    Description: FABP4 measured by ELISA; patients classified as responders (decrease) vs. rebound/non-responders (no decrease or increase)

    Measured: Time Frame: Baseline, 3 months, 6 months

Secondary outcomes (11)

  1. Change in BMI from baseline to 3 and 6 months

    Change in BMI from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  2. Change in body weight from baseline to 3 and 6 months

    Change in body weight from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  3. Change in fat mass (bioelectrical impedance) from baseline to 3 and 6 months

    Change in fat mass and fat-free mass (bioelectrical impedance) from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  4. Change in fat-free mass (bioelectrical impedance) from baseline to 3 and 6 months

    Change in fat mass and fat-free mass (bioelectrical impedance) from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  5. Change in HOMA-IR from baseline to 3 and 6 months

    Change in HOMA-IR from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  6. Change in IL-6 from baseline to 3 and 6 months

    Change in hsCRP and IL-6 from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  7. Change in hsCRP from baseline to 3 and 6 months

    Change in hsCRP and IL-6 from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  8. Change in fasting GLP-1 from baseline to 3 and 6 months

    Change in fasting GLP-1 and PYY from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  9. Change in fasting PYY from baseline to 3 and 6 months

    Change in fasting GLP-1 and PYY from baseline to 3 and 6 months

    Measured: Baseline, 3 months, 6 months

  10. Baseline-Adjusted 6-Month Change in Body Mass Index (BMI) by FABP4 Response Group

    6-month change in BMI (kg/m²) was compared between FABP4 responder and rebound (non-responder) groups using an ANCOVA model adjusted for baseline (preoperative) serum FABP4 concentration (log-transformed). FABP4 response group was defined by the direction of change in serum FABP4, measured by enzyme-linked immunosorbent assay (ELISA), from baseline to 6 months after Roux-en-Y gastric bypass.

    Measured: Baseline, 3 months, 6 months

  11. Odds Ratios for Predictors of 6-Month FABP4 Rebound: Early (0-3-Month) BMI Change, Age, and Sex

    Odds ratios (OR) with 95% confidence intervals were estimated using a multivariable logistic regression model to identify predictors of FABP4 rebound status at 6 months after Roux-en-Y gastric bypass. Covariates included early (0-3-month) percentage change in body mass index (BMI), age (years), and sex (male/female). FABP4 rebound was defined as an increase in serum FABP4 concentration, measured by enzyme-linked immunosorbent assay (ELISA), from baseline to 6 months postoperatively.

    Measured: Baseline, 3 months, 6 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted19 Aug 2026
  2. Study start22 Apr 2013
  3. Primary completion5 Dec 2014
  4. Study completion10 Feb 2015

Resources

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
28 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07774208
Sponsor's protocol ID
2025/2451
Acronym
FABP4-RYGB
Status last verified
Aug 2026
First submitted
12 Aug 2026
Last updated
19 Aug 2026
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: Types of Supporting Information: * Study Protocol * Statistical Analysis Plan * Analytic Code IPD Sharing Time Frame: Beginning 12 months and ending 36 months following publication of the primary manuscript. IPD Sharing Access Criteria: De-identified individual participant data will be made available to researchers who provide a methodologically sound proposal, following review and approval by the corresponding author and the Istanbul University Istanbul Faculty of Medicine Clinical Research Ethics Committee, and subject to a signed data access agreement. Requests should be directed to the corresponding author.

Questions about this trial

What is this clinical trial studying?

An observational study of Obesity (BMI>30) and Obesity (BMI > 35), run by Istanbul University.

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 2 inclusion and 3 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: finished, as of the sponsor's last update on 19 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Measure: Change in serum FABP4 level from baseline to 6 months after RYGB (time frame: Time Frame: Baseline, 3 months, 6 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07774208.

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 19 Aug 2026.

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