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NCT Number: NCT07035483

Changes in Fat and Muscle Tissue Function and Their Impact on Metabolic Health After Bariatric Surgery

This prospective, single-center observational cohort study aims to explore the relationship between skeletal muscle quality, fat distribution, and metabolic health in Chinese patients with obesity, and to evaluate how bariatric surgery influences these parameters.

A total of 120 participants will be enrolled, including 60 patients undergoing bariatric surgery and 60 age- and sex-matched healthy controls. The study involves cross-sectional comparisons of ectopic fat and muscle composition, as well as longitudinal follow-up of surgical patients at multiple time points up to 5 years postoperatively.

MRI will be used to quantify regional fat and muscle composition, while metabolic parameters, inflammatory markers, and gut microbiota profiles will also be assessed. Primary outcomes include skeletal muscle mass and fat infiltration, visceral and subcutaneous fat volumes, and changes in insulin resistance.

This study seeks to clarify the mechanisms by which bariatric surgery improves metabolic function and to identify early changes in muscle-fat composition that may predict long-term metabolic outcomes.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Obesity and Obesity-related Medical Conditions Adipose Tissue, Abdominal Body Weight Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Metabolic Diseases Metabolic Syndrome Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Sarcopenic Obesity Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Xiangya Third Hospital, Central South University

Changsha, Hunan, 410013, China

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

(For Surgical Group):

  • Aged 18 to 65 years (inclusive)
  • Meets clinical criteria for sleeve gastrectomy or Roux-en-Y gastric bypass surgery
  • Willing and able to comply with study procedures and follow-up visits Capable of understanding and signing the informed consent form

Inclusion criteria

(For Healthy Control Group):

  • Aged 18 to 65 years (inclusive)
  • Body mass index (BMI) between 18.0 and 24.0 kg/m²
  • No history of metabolic disorders (e.g., hypertension, type 2 diabetes, fatty liver disease, or dyslipidemia)
  • No history of gastrointestinal surgery
  • Able to undergo MRI and willing to provide baseline clinical data and biological samples
  • Able to understand and sign informed consent

Exclusion criteria

  • Type 1 diabetes mellitus or latent autoimmune diabetes in adults (LADA)
  • History of pancreatitis, gastrointestinal or pancreatic surgery
  • Severe complications of type 2 diabetes or major organ dysfunction that may affect surgical safety
  • Active alcohol or drug dependence, severe psychiatric illness, cognitive impairment, or suicidal ideation
  • Pregnant or breastfeeding women, or women planning pregnancy during the follow-up period
  • Contraindications to MRI examination, including:

Cardiac pacemaker Artificial heart valves Ferromagnetic vascular clips Metallic foreign bodies in the eye

∙Considered unsuitable for the study by investigators based on risk-benefit assessment

Treatment and study plan

bariatric surgery

Procedure

This is a prospective observational study evaluating the metabolic and tissue-level effects of bariatric surgery in obese individuals. The intervention includes either laparoscopic sleeve gastrectomy (LSG) or Roux-en-Y gastric bypass (RYGB), performed according to standard clinical guidelines. No experimental procedures are added beyond routine care. Skeletal muscle quality and visceral fat distribution are assessed using MRI and clinical biomarkers at multiple postoperative time points (baseline, 3 months, 12 months, and annually up to 5 years). A healthy control group undergoes baseline evaluation only, without surgical intervention.

Primary outcomes

  1. Change in Skeletal Muscle Fat Infiltration and Quality (measured by MRI)

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    Quantitative evaluation of intramuscular fat content using MRI-derived proton density fat fraction (PDFF) and muscle attenuation indices in the thigh and paraspinal muscles. Muscle quality will be assessed by MRI signal intensity and texture features to detect early changes in muscle composition post-surgery.

  2. Change in Visceral and Subcutaneous Fat Volume (measured by MRI)

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    MRI-based measurement of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), liver fat percentage (LFP), and pancreatic fat percentage (PFP) to track region-specific fat redistribution after bariatric surgery.

Secondary outcomes

  1. Change in fasting glucose

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    Fasting glucose to evaluate metabolic improvement after surgery.

  2. Change in HbA1c

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    HbA1c to evaluate metabolic improvement after surgery.

  3. Change in triglycerides

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    Triglycerides to evaluate metabolic improvement after surgery.

  4. Change in LDL-C

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    LDL-C to evaluate metabolic improvement after surgery.

  5. Change in HDL-C

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    HDL-C to evaluate metabolic improvement after surgery.

  6. Change in total cholesterol

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    total cholesterol to evaluate metabolic improvement after surgery.

  7. Change in insulin resistance

    Time frame: Baseline, 3 months, 12 months, annually up to 5 years

    HOMA-IR to evaluate metabolic improvement after surgery.

  8. Change in body mass index

    Time frame: Baseline, 3 months, 12 months annually up to 5 years

    Body mass index (BMI), calculated as weight in kilograms divided by height in meters squared (kg/m²), will be measured at baseline and follow-up visits to assess changes in overall adiposity after bariatric surgery. BMI will be used as a general anthropometric indicator of weight loss efficacy over time.

  9. Change in waist circumference

    Time frame: Baseline, 3 months, 12 months annually up to 5 years

    Waist circumference will be measured in centimeters using a standardized tape measure at the midpoint between the lowest rib and the iliac crest. This anthropometric indicator will be used to evaluate central (abdominal) fat reduction following bariatric surgery. Measurements will be taken at baseline and at follow-up time points to assess longitudinal changes.

  10. Change in hip circumference

    Time frame: Baseline, 3 months, 12 months annually up to 5 years

    Hip circumference will be measured in centimeters at the widest portion of the buttocks using a standardized measuring tape. This anthropometric measure will help assess changes in fat distribution following bariatric surgery. Measurements will be recorded at baseline and follow-up visits to monitor longitudinal changes in body composition.

Sponsors and collaborators

Lead sponsor

Shaihong Zhu

Other

Registry information

Official study title

Changes in Adipose and Muscle Tissue Function and Their Impact on Metabolic Health Following Bariatric Surgery

Important dates

Study start
2025
Primary completion
2025
Study completion
2029
First posted
Jun 25, 2025
Registry last updated
Jun 25, 2025

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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