The Effect of Probiotics on Systemic Inflammation and Metabolic Endotoxemia in Patients Undergoing Bariatric Surgery

This study explores the effects of probiotic administration on the outcomes of surgical treatment, and also on the state of the intestinal microbiota and the intestinal barrier. The study protocol is designed as a randomized double-blind placebo-controlled clinical trial. Patients qualified for bariatric surgery will be randomized to receive probiotics or a placebo for 12 weeks. Researchers are going to evaluate changes in intestinal microbiota, epithelial permeability, weight loss, postoperative complications, and serum parameters reflecting inflammation, metabolic profile, and metabolic endotoxemia.

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).

Eligibility Criteria:
Inclusion Criteria:

* qualification for LSG, RYGB, OAGB bariatric surgery
* age over 18
* written consent to participate in the study

Exclusion Criteria:

* allergy/intolerance to any of the ingredients of the preparations,
* inflammatory bowel diseases,
* current antibiotic therapy,
* immunosuppression,
* biological treatment,
* long-term antibiotic therapy,
* taking probiotics in the 1 month prior to study enrollment,
* neurodegenerative diseases.