Role of serotonin hormone in weight regain after sleeve gastrectomy

Laparoscopic sleeve gastrectomy (LSG) is gaining popularity as bariatric surgery, a small percentage of subjects regain weight after surgery. This study was designed to evaluate body weight changes over a period of two years after LSG and investigate the role of serotonin in regulating energy balance. This is a prospective cohort study. A total of 92 patients with morbid obesity (64 women and 28 men) underwent LSG. All the participants were subjected to physical examination and detailed medical history. Anthropometric measurements were accomplished pre-operative and post-operatively at a frequency of four times per year for two years follow-up. Laboratory investigations were performed pre-operatively, and one and two years post-operatively. Blood samples were collected in the fasting state; for glucose, lipid profile and hormonal assays. Hormones measured were plasma insulin, leptin, serotonin and ghrelin. Results revealed that 35.7% weight loss occurred after one year. However, there was variability in the individual weight loss curve during the period between the first and second post-operative years. Thus, patients were divided into two groups: group I included 78 patients (84%) who maintained the lost weight, and group II included 14 patients (16.0%) who regained weight within 24 months post-operatively. Correlation with BMI revealed positive correlation with leptin and serotonin, whilst negative correlation with ghrelin in group II patients. Mechanisms of weight loss after LSG are not only attributable to gastric restriction but also to the neurohormonal changes. In addition, serotonin may possibly contribute to the interplay of regulatory systems of energy homeostasis.