Effect of Bariatric Surgery on Brain Insulin Sensitivity

Study Overview
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Brief Summary
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Adiposity is associated with prediabetes and type 2 diabetes. In very severe cases of adiposity in combination with type 2 diabetes, bariatric surgery has proven to be a successful therapy option. So far the molecular mechanisms that lead to an improvement of type 2 diabetes after bariatric surgery are not fully understood. It is planned to characterize the metabolic and neuroendocrine changes in subjects before and after bariatric surgery. One special focus of the study is brain insulin resistance, a condition known to be associated with obesity with impact on the brain and whole body metabolism.

Official Title
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Metabolic Characterization of Subjects With Adipositas Before and After Bariatric Surgery

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 between 18 and 75 years planned bariatric surgery (laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy) stable medication 10 weeks before begin of the study Exclusion Criteria: persons who wear non-removable metal parts in or on the body. persons with reduced temperature sensitivity and / or increased sensitivity to heating of the body cardiovascular disease can not be ruled out, e.g. manifest coronary heart disease, heart failure greater than NYHA 2, previous heart attack, stroke condition persons with hearing impairment or increased sensitivity to loud noises people with claustrophobia minors or non-consenting subjects are also excluded subjects with an operation less than 3 months neurological and psychiatric disorders subjects with hemoglobin Hb <11 g / dl hypersensitivity to any of the substances used

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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>Subjects undergoing laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy. | Procedure: Bariatric surgery<br>* laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Central insulin sensitivity | Central insulin sensitivity will be assessed by fMRI after application of nasal insulin or placebo. | Central insulin sensitivity will be assessed as change before bariatric surgery and 6 months afterwards. | 
| Peripheral insulin sensitivity | Peripheral insulin sensitivity will be assessed by oral glucose tolerance test. | Peripheral insulin sensitivity will be assessed by oral glucose tolerance as change before bariatric surgery and 6 months afterwards. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Whole body fat distribution | Body fat distribution will be assessed by MRI | Body fat distribution will be assessed by MRI prior bariatric surgery and 6 months afterwards. | 
| Liver fat content | Liver fat content will be assessed by MRS | Liver fat content will be assessed by MRS prior bariatric surgery and 6 months afterwards. | 
| Metabolic rate | Metabolic rate will be assessed by indirect calorimetry | Metabolic rate will be assessed by indirect calorimetry prior bariatric surgery and 6 months afterwards. | 
| Response to food cues | Food cues will be rated for palatability on a visual analogue scale | Change in response to food cues will be assessed before bariatric surgery and 6 months afterwards. | 
| Trail-making test | Trail-making test will be performed | Change in trail-making test will be assessed before bariatric surgery and 6 months afterwards. | 
| Hopkins-verbal learning test | Hopkins-verbal learning test will be performed | Change in Hopkins-verbal learning test will be assessed before bariatric surgery and 6 months afterwards. | 
| Glucose tolerance | Glucose tolerance will be assessed by 75g oral glucose tolerance test. | Glucose tolerance will be assessed by 75g oral glucose tolerance test prior to bariatric surgery and 6 months afterwards. | 
| Insulin secretion | Insulin secretion will be assessed by insulin measurements during 75g oral glucose tolerance test. | Insulin secretion will be assessed by insulin measurements during 75g oral glucose tolerance test prior to bariatric surgery and 6 months afterwards. | 
| Weight loss | Body weight will be measured before and 6 months after surgery. | Weight loss before and 6 months after surgery. |