Different Limb Lengths in Gastric Bypass Surgery (SLIM) - Part 3: Metabolism and Inflammation

Swiss Multicenter Randomized Controlled Trial on Different Limb Lengths in Gastric Bypass Surgery (SLIM Trial) - Part 3: Metabolic Mechanisms and Inflammatory Response

Investigation of underlying metabolic mechanisms and impact on the two surgical procedures on inflammatory factors.

The aim of this project is to investigate underlying metabolic mechanisms in a subpopulation of patients of the SLIM trial, where a laparoscopic proximal Roux-en-Y gastric bypass (LRYGB) with a longer biliopancreatic limb (BPL) is compared to a standard LRYGB. For this purpose, the aim is to examine differences in number of intestinal enteroendocrine cells, subpopulations of intestinal macrophages, and gene expression or DNA-methylation in tissue samples obtained by colonoscopy from the ileum and transverse colon. In addition, gut microbiota (from colon biopsy and fecal samples), meal-stimulated gut hormone profiles, glycemic control, and metabolite patterns (metabolomics; in blood, urine, stool and breath) including plasma bile acid concentrations preoperatively and 6 months post-surgery will be examined. Body composition (fat mass and lean mass) will be measured by means of BIA (bioimpedance analysis; Biacorpus).

Inclusion Criteria:

• 2 x 25 patients with morbid obestiy (BMI of 35 kg/m2 or higher) who comply with the regulatory rules for bariatric surgery in Switzerland (SMOB guidelines) and participate in the SLIM Trial
• 15 healthy lean controls

Exclusion Criteria:

• general contraindications to kind of surgery
• known or suspected non-compliance
• inability to follow the procedures of the study, e.g. due to language problems, psychological disorders etc. of the participant
• participation in another interventional study
• BMI > 60 kg/m2
• height < 145 cm
• CL length of < 180 cm as measured intraoperatively
• ASA physical status classification > III
• inflammatory bowel disease
• diabetes
• intake of corticosteroids, anti-inflammatory/ immunosuppressive drugs potentially altering immune cells
• clinical signs of current infection
• known anemia (e.g. hemoglobin < 110g/L for males, < 100g/L for females)
• known neutropenia (e.g. leucocyte count < 1.5 x 10^9/L or ANC < 0.5 x 10^9/L)
• known immunodeficiency, e.g. HIV
• known vasculitis, collagenosis
• known adrenal insufficiency and/or substitution with glucocorticoids
• risky daily alcohol consumption (> 24g/d for males, > 12g/d for females)
• drug abuse
• known liver cirrhosis Child B or C
• known uncontrolled congestive heart failure
• known uncontrolled malignant disease
• currently pregnant or breastfeeding