The Metabolic and Genetic Drivers of Body Composition Changes Following Weight Loss Surgery

NCT07178704 | Recruiting

• 1 other identifier: 24-0361
• Study Type: observational
• Target: 110
• Locations: 1 country
• Sites: 1

Brief Summary

Weight loss surgery is very good at reducing body weight but it can also cause the loss of both muscle and strength. Some patients undergoing weight loss surgery do not achieve their weight loss goals and regain the weight they lost. When this occurs, the loss of muscle and strength combined with the regain of weight can impact the individual's quality of life and ability to remain active and mobile. The purpose of this study is to understand the behavioral, biological, and genetic factors that influence the success of weight loss surgery and its impact on muscle mass. Bariatric surgery patients participating in the trial will be monitored prior to, and for a year following weight loss surgery, with data collected about their eating habits, hand grip strength, and the loss of fat, muscle, and body weight following surgery. Some patients will be additionally invited to undergo detailed metabolic assessment, where we will measure how their body uses nutrients it consumes, the composition of their body (e.g. how much lean and fat tissue they have and where it is stored), identify the bacteria living in their gut, and determine their physical performance. In all patients a small sample of gut tissue will be collected at a routine endoscopy performed in advance of weight loss surgery to identify the expression (activity) of genes in their DNA. Healthy subjects will also be recruited to allow us to compare between healthy weight individuals and those undergoing weight loss surgery. On a single occasion, the healthy volunteers will undergo the same detailed metabolic assessment performed in patients as described above. We will not examine the bacteria living in the gut of the healthy volunteers, nor will we collect gut tissue from these individuals.

Conditions

Bariatric Surgery Patients

Keywords

Body composition; Sarcopenia; Weight loss surgery; Muscle function; Protein metabolism

Outcome Measures

Primary Outcomes (2)

• Whole-body Protein Turnover Rates

  Whole-body protein turnover rates measured over a 48 hour period, accomplished via the consumption of a drink containing isotopically labelled (15N) alanine and the subsequent collection of urine for two days. Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.

  Measured at baseline in both healthy volunteers & patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.

• Association between foregut gene expression and degree of weight reduction

  Assessed only in patients. Gene expression of the foregut will be analyzed in tissue collected from patients during the routine pre-operative upper endoscopy. Subsequently, participants will be stratified into those achieving: \<10%, 10-20%, or \>20% weight loss 12 months post-surgery, and differentially expressed genes between the three groups determined.

  A single occasion from tissue collected during the routine pre-operative upper endoscopy. (baseline)

Secondary Outcomes (8)

• Dietary Protein Intake

  Measured at baseline in both healthy volunteers & patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.

• Body weight

  Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.

• Body composition

  Measured at baseline in both healthy volunteers & bariatric surgery patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.

• Short Physical Performance Battery Test

  Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.

• Handgrip Strength

  Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.

Other Outcomes (1)

• Changes in the Gut Microbiome post-bariatric surgery

  Measured at baseline and two further occasions across a 1 year period post surgery.

Study Arms (2)

Bariatric Surgery Patients

Patients due to undergo either sleeve gastrectomy or gastric bypass surgery.

Healthy Control Subjects

Healthy weight individuals recruited from the local population.

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients will be recruited from those electing to undergo bariatric surgery at the University of Texas Medical Branch. Healthy volunteers will be recruited from individuals responding to adverts targeting the Houston - Galveston region.

You may qualify if:

• Age: 30 to 50 years at time of consent
• BMI: 20-25 kg.m-2
• Male or Female
• All races and ethnic backgrounds
• Ability to speak and read English
• Subject has provided informed consent in a manner approved by the IRB and is willing and able to comply with the trial procedures.
• Age: 18 to 65 years at time of consent
• BMI: 35-50 kg.m-2
• Scheduled to undergo bariatric surgery at UTMB
• All races and ethnic backgrounds
• Ability to speak and read English
• Subject has provided informed consent in a manner approved by the IRB and is willing and able to comply with the trial procedures.
• Age: restricted to 30 to 50 years of age
• Undergoing gastric bypass surgery

You may not qualify if:

• Heart, vascular, or pulmonary disease
• Uncontrolled blood pressure (systolic BP \> 170, diastolic BP \> 95 mmHg)
• Impaired renal function (creatinine \> 1.5 mg/dl)
• Anemia (hematocrit \< 33 % or donated blood in the past 12 weeks.)
• Diabetes mellitus or other untreated endocrine or metabolic disorder
• Recent (5 years or less) history of cancer
• Systemic steroids, anabolic steroids, growth hormone, or immunosuppressant use within 6 months.
• Recent (6 months) adherence to a weight-loss or weight-gain diet, resulting in a weight change of 10% or more.
• Body mass index \> 25.5 kg.m-2
• Body mass index \< 19.5 kg.m-2 or recent history (\< 12 months) of disordered eating.
• Acute infectious disease or chronic infection.
• Pregnancy or breast-feeding.
• Recent (1 month) consumption of protein-based sports supplements.
• Any medical condition that, in the opinion of the investigator, would place the subject at increased risk for participation.
• Known allergic reaction to any agent under investigation or required by the protocol, including Phenylketonuria.

Sponsors & Collaborators

• The University of Texas Medical Branch, Galveston: lead

Study Sites (1)

The University of Texas Medical Branch

Galveston, Texas, 77555, United States

RECRUITING

Biospecimen

Retention: SAMPLES WITH DNA

Urine; Fecal; Plasma; Serum; Foregut tissue

MeSH Terms

Conditions

Sarcopenia

Condition Hierarchy (Ancestors)

Muscular Atrophy; Neuromuscular Manifestations; Neurologic Manifestations; Nervous System Diseases; Atrophy; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms; Signs and Symptoms

Study Officials

• Andrew J Murton, PhD

  The University of Texas Medical Branch

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Andrew J Murton, PhD

CONTACT

409-772-0185; ajmurton@utmb.edu

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 22, 2025
• First Posted: September 17, 2025
• Study Start: November 4, 2025
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): August 1, 2027
• Last Updated: November 12, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)