Gut Hormones as Mediators of Different Weight Loss Responses After Roux-en-Y Gastric Bypass

Study Overview
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Brief Summary
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After gastric bypass, 10-20% of patients will obtain a suboptimal weight loss, often defined as <50% of the excess body weight. Exaggerated meal related secretion of gut hormones seem important for appetite reduction and subsequent weight loss after gastric bypass, however it is not clear whether different gut hormone responses are responsible for different postoperative weight loss responses. The purpose of the study is to investigate gut hormone secretion, vagal integrity and the effect of octreotide on ad libitum food intake in patients with suboptimal weight loss after gastric bypass and compare results to a matched group of gastric bypass operated patients with high postoperative weight loss but similar age, sex and preoperative BMI.

Conditions
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Bariatric Surgery (Gastric Bypass), Severe Obesity

Intervention / Treatment
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* Other: Meal tests after saline injection
* Other: Meal tests after octreotide injection
* Other: Sham feeding


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Uncomplicated primary Roux-en-Y gastric bypass >12 months ago Postoperative weight loss of >60%EBL or <50%EBL. Exclusion Criteria: Inadequately treated thyroid disease Hemoglobin <6.5 mM Pregnancy or breastfeeding

Ages Eligible for Study
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Minimum Age: 20 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
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Low EBL<br>Gastric bypass operated patients with low postoperative excess body weight loss (EBL) <50%. Interventions: Meal tests after saline/octreotide injection in a randomized order, sham feeding. | Other: Meal tests after saline injection<br>* Fixed breakfast meal and ad libitum lunch meal<br>Other: Meal tests after octreotide injection<br>* Fixed breakfast meal and ad libitum lunch meal<br>Other: Sham feeding<br> <br> |
| Other: High EBL<br>Gastric bypass operated patients with high postoperative excess body weight loss (EBL) >70% matched with respect to age, gender and preoperative BMI in the LowEBL group. Interventions: Meal tests after saline/octreotide injection in a randomized order, sham feeding. | Other: Meal tests after saline injection<br>* Fixed breakfast meal and ad libitum lunch meal<br>Other: Meal tests after octreotide injection<br>* Fixed breakfast meal and ad libitum lunch meal<br>Other: Sham feeding<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glucagon-like peptide-1 (GLP-1) secretion (Between groups difference in incremental Area-under-the curve (iAUC) GLP-1 after fixed breakfast meal on saline day) | Between groups difference in iAUC GLP-1 after fixed breakfast meal on saline day | 0-240 min | 
| Peptide YY (PYY) secretion (Between groups difference in iAUC PYY after fixed breakfast meal on saline day) | Between groups difference in iAUC PYY after fixed breakfast meal on saline day | 0-240 min | 
| Ghrelin secretion (Between groups difference in iAUC Ghrelin after fixed breakfast meal on saline day) | Between groups difference in iAUC Ghrelin after fixed breakfast meal on saline day | 0-240 min | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ad libitum food intake | Between groups difference in ad lib food intake | 240 min | 
| Effect of octreotide on Ad libitum food intake (Between groups difference in %change in ad lib food intake between saline and octreotide day) | Between groups difference in %change in ad lib food intake between saline and octreotide day | 240 min | 
| Vagal insufficiency (Between groups difference in % change in pancreatic polypeptide (PP) from fasting to early peak levels (15-30 min) after sham feeding) | Between groups difference in % change in PP from fasting to early peak levels (15-30 min) after sham feeding | 0-30 min |