Brown Fat Activity and Bariatric Surgery

Study Overview
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Brief Summary
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The mechanisms of bariatric surgery-induced weight loss go beyond reductions in calorie intake and may involve several other pathways. Recently, brown adipose tissue (BAT) has been added as another potential player. Activation of BAT results in enhanced energy expenditure and promotes weight loss. Here, the investigators will study the effects of bariatric surgery on BAT function by PET/CT studies and molecular analyses of adipose biopsies. The investigators will explore different pathways that may affect BAT activation in this patient population.

Official Title
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The Role of Alternatively Activated Brown Fat in Bariatric Surgery-mediated Metabolic Improvements

Conditions
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Obesity

Intervention / Treatment
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* Procedure: Bariatric Surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 20 - 50 years Body mass index (BMI) 35 - 55kg/m2 Exclusion Criteria: Endocrine disease (except hyperlipidemia and substituted hypothyroidism or type 2 diabetes with fasting glucose concentrations <120mg/dl), kidney disease, inflammatory bowel disease, autoimmune or rheumatologic diseases that require immunosuppressive treatment, active oncologic disease, heart failure. Medication for any of the above mentioned conditions. Antibiotic treatment in the past three months Pregnancy

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bariatric Surgery<br>Patients will undergo either Omega Loop Gastric Bypass or Sleeve Gastrectomy. The decision which type of surgery will be performed, will by made by the surgeon and the patient based on clinical considerations and the patient's wishes. | Procedure: Bariatric Surgery<br>* Patients will undergo bariatric surgery as routinely scheduled. The type of bariatric procedure will be suggested by the surgeon based on clinical considerations.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in BAT activity after bariatric surgery | The primary outcome of this study is to determine whether Omega Loop Gastric Bypass and Sleeve Gastrectomy result in increased BAT activity | 4 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bariatric surgery-induced changes in gut microbiota, bile acid composition and other circulating factors | Any pre-versus postsurgical changes of the gut microbiota or bile acid composition or other circulating factors will be evaluated. | 4 years | 
| Association between changes in BAT activity, transcriptional BAT markers and alterations in the gut microbiota profile or bile acid composition | Linear regression analyses will be performed to determine any association between BAT activity or molecular signature and changes in the gut microbiota or bile acids | 4 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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BAT, Bariatric Surgery, Energy Metabolism