FABP4 Response After Roux-en-Y Gastric Bypass

NCT07774208 | Completed

• 1 other identifier: 2025/2451
• Study Type: observational
• Target: 28
• Locations: 0 countries
• Sites: N/A

Brief 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. 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.

Conditions

Obesity (BMI>30); Obesity (BMI > 35); Insulin Resistance; Bariatric Surgery; Bariatric Surgery (Gastric Bypass)

Keywords

FABP4; Roux-en-Y gastric bypass; adipokine; bariatric surgery; weight loss; adipose tissue remodeling; GLP-1; PYY; inflammation

Outcome Measures

Primary Outcomes (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)

  Time Frame: Baseline, 3 months, 6 months

Secondary Outcomes (11)

• Change in BMI from baseline to 3 and 6 months

  Baseline, 3 months, 6 months

• Change in body weight from baseline to 3 and 6 months

  Baseline, 3 months, 6 months

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

  Baseline, 3 months, 6 months

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

  Baseline, 3 months, 6 months

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

  Baseline, 3 months, 6 months

Study Arms (2)

Group/Cohort Label: FABP4 Responders

Description: 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-responders

Description: Patients with no decrease or an increase in serum FABP4 from baseline to 6 months after Roux-en-Y gastric bypass (n=18)

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• 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

You may not qualify if:

• 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)

Sponsors & Collaborators

• Istanbul University: lead

Biospecimen

Retention: SAMPLES WITHOUT DNA

Banked serum/plasma aliquots stored at -80°C, single freeze-thaw cycle prior to FABP4 assay

MeSH Terms

Conditions

Obesity; Insulin Resistance; Weight Loss; Inflammation

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Hyperinsulinism; Glucose Metabolism Disorders; Metabolic Diseases; Body Weight Changes; Pathologic Processes

Study Officials

• Bedia Fulya Calikoglu, M.D., PhD.

  Istanbul University, Istanbul Medical Faculty

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Lecturer

Study Record Dates

• First Submitted: August 12, 2026
• First Posted: August 19, 2026
• Study Start: April 22, 2013
• Primary Completion: December 5, 2014
• Study Completion: February 10, 2015
• Last Updated: August 19, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ANALYTIC CODE
• Time Frame: Beginning 12 months and ending 36 months after publication of the primary manuscript, upon reasonable request to the corresponding author.
• Access Criteria: De-identified individual participant data, the study protocol, statistical analysis plan, and analytic code will be made available to qualified researchers who submit a methodologically sound proposal to the corresponding author. Requests will be reviewed for scientific merit and data protection compliance and require approval from the Istanbul University Istanbul Faculty of Medicine Clinical Research Ethics Committee and a signed data access/use agreement prior to release, in order to protect participant confidentiality given the modest single-center cohort size (n=27).