Evaluation of Metabolic Parameters, Intestinal Permeability and Gastrointestinal Symptoms After Bariatric Surgery in Body Weight Management

Evaluation of Postoperative Metabolic Parameters, Intestinal Permeability and Gastrointestinal Symptoms in Body Weight Management After Laparoscopic Sleeve Gastrectomy

This study aims to evaluate the changes in metabolic parameters, intestinal permeability, and gastrointestinal symptoms in individuals who have undergone bariatric surgery (Laparoscopic Sleeve Gastrectomy - LSG) for obesity treatment.

Obesity is a chronic disease associated with serious health complications including type 2 diabetes, hypertension, cardiovascular disease, and metabolic disorders. Bariatric surgery is currently the most effective treatment method for morbid obesity. However, monitoring patients after surgery in terms of metabolic health, gut permeability, and gastrointestinal symptoms is crucial for long-term success.

In this study, 40 volunteers (aged 19-50) who have undergone LSG surgery within the last month will be followed for 6 months. At the beginning of the study and 6 months later, the following will be assessed:

• Metabolic parameters: fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) cholesterol, and insulin levels
• Intestinal permeability markers: zonulin, secretory immunoglobulin A (IgA), and lipopolysaccharide (LPS) levels
• Gastrointestinal symptoms: assessed using the Gastrointestinal Symptom Rating Scale (GSRS)
• Anthropometric measurements: body weight, height, waist and hip circumference, BMI
• Nutritional intake: 3-day dietary records

The study will be conducted at Bursa Yıldırım Doruk Hospital, General Surgery Clinic. Results will contribute to understanding the relationship between bariatric surgery and gut health, potentially helping to prevent postoperative complications.

Obesity is defined by the World Health Organization (WHO) as abnormal or excessive fat accumulation that presents a risk to health. Bariatric surgery, particularly Laparoscopic Sleeve Gastrectomy (LSG), is considered the most effective long-term treatment for morbid obesity.

This prospective observational study will be conducted at Bursa Yıldırım Doruk Hospital with 40 volunteers who have undergone LSG within the last month. Participants will be evaluated at baseline (immediately after surgery) and at 6 months post-surgery.

Assessments include:

1. Anthropometric Measurements: Body weight, height, waist and hip circumference will be measured. BMI and waist-to-hip ratio will be calculated according to WHO criteria.
2. Biochemical Parameters: Fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) cholesterol, and insulin levels will be obtained from patient records. Zonulin, secretory immunoglobulin A (IgA), and lipopolysaccharide (LPS) levels will be analyzed using ELISA method (Biotek TS800) with commercial kits (RelAssay® Diagnostics, Ankara, Turkey) at Ankara Diagen Laboratory. Samples will be stored at -20°C until analysis.
3. Gastrointestinal Symptom Rating Scale (GSRS): A validated 15-item scale assessing five dimensions: diarrhea, indigestion, constipation, abdominal pain, and reflux. Scores range from 1 (no discomfort) to 7 (very severe discomfort). Turkish validity and reliability was established by Turan and Asti (2011).
4. Dietary Assessment: 3-day dietary records will be collected and analyzed using the Nutrition Information System (BeBIS) 8.2 software. Results will be evaluated according to the Turkish Dietary Guidelines 2022 (TUBER 2022).

Statistical analyses will be performed using the Statistical Package for the Social Sciences (SPSS) 22.0. Normal distribution will be assessed using Kolmogorov-Smirnov/Shapiro-Wilk tests. Results will be expressed as mean ± standard deviation for continuous variables and frequency/percentage for categorical variables.

Inclusion Criteria:

• Underwent Laparoscopic Sleeve Gastrectomy (LSG) within the last 1 month
• Aged between 19-50 years
• BMI ≥40 kg/m² or BMI ≥35 kg/m² with obesity-related comorbidities
• Signed informed consent form
• Non-smoker and non-alcohol dependent

Exclusion Criteria:

• Did not undergo or is not planned to undergo LSG
• Outside the age range of 19-50 years
• Did not sign the informed consent form
• BMI <40 kg/m² or BMI <35 kg/m² without obesity-related comorbidities
• Smoker or alcohol dependent
• Has an inflammatory disease
• Currently using probiotics, antibiotics, or fiber supplements
• Has a psychiatric disorder