The Effect of Probiotic Supplementation on Systemic Inflammation and Metabolic Endotoxemia in Morbidly Obese Patients Undergoing Bariatric Surgery

The study is designed as a randomized double-blind placebo-controlled clinical trial with a 12-week probiotics intervention period. Eighty patients qualified for one of 3 types of bariatric surgery Roux-en-Y Gastric Bypass (RYGB), One-Anastomosis Gastric Bypass (OAGB), Laparoscopic Sleeve Gastrectomy (LSG) will be randomized to receive probiotics or a placebo. The time frame for the study is 6 months before and 6 months after surgery.

During this time, it is planned to collect stool samples at 5-time points: before the start of the study, before the introduction of probiotic therapy, 2 weeks before the operation, and 3 and 6 months after the operation. Collected fecal samples will be subjected to quantitative and qualitative content of the intestinal microbiota using the new generation sequencing method, as well as intestinal permeability parameters such as I-FABP (Intestinal fatty acid-binding protein), bacterial short-chain fatty acids (SCFA), and lipopolysaccharide (LPS).

Simultaneously with the collection of stool samples, an assessment of the patient's nutrition will be performed using the food frequency questionnaire (FFQ) and three-day dietary recall.

The blood samples will be collected at 4-time points: before the start of the study, before the operation, and 3 and 6 months after the operation. The following parameters will be marked in the collected blood samples: glucose, insulin, HbA1c, liver tests: ALT (Alanine transaminase), AST (Aspartate transaminase), GGTP (Gamma-glutamyl Transferase), alkaline phosphatase (ALP), bilirubin; lipid profile, CRP (C-reactive protein), total protein, albumin, inflammatory markers: IL-6, IL-10, Tumor necrosis factor-α (TNF-α), IL-8, IL-R2.

During the examination, tissue samples will be taken at 2-time points. The first is during routine gastroscopy before surgery. Gastroscopy will be performed before the inclusion of the probiotic. Duodenal and stomach biopsy will be performed during gastroscopy. The second time tissue samples will be collected intraoperatively. Gastric specimens will be collected from patients undergoing LSG. Patients qualified for RYGB and OAGB surgery will undergo gastric and jejunum biopsy. The parameters of the intestinal barrier status will be assessed in the collected tissues: Plasmalemma Vesicle-Associated Protein-1 (PLVAP-1), and Regenerating Islet Derived Protein 3 Alpha (Reg3α).