Hormonal and Microbiota Modulation After Endoscopic Sleeve Gastroplasty

Obesity is a chronic disease with increasing prevalence, projected to affect up to 25% of the French population by 2030, and is associated with significant morbidity, mortality, and healthcare burden. Bariatric surgery, including sleeve gastrectomy and gastric bypass, remains the reference treatment for severe obesity but is irreversible and associated with procedural risks. Less invasive alternatives have emerged, including pharmacological treatments (GLP-1 receptor agonists and multi-agonists) and endoscopic procedures such as endoscopic sleeve gastroplasty (ESG). These approaches have demonstrated efficacy in weight loss and metabolic improvement, although pharmacological treatments are limited by weight regain after discontinuation and reduced long-term adherence. Sleeve gastrectomy, the most commonly performed bariatric procedure in France, induces weight loss through gastric restriction, hormonal changes (including reduced ghrelin and increased GLP-1 and PYY), and accelerated gastric emptying. In contrast, ESG is a minimally invasive endoscopic technique with mechanisms that remain incompletely understood, with emerging data suggesting delayed gastric emptying. Beyond mechanical restriction, the metabolic effects of bariatric interventions involve complex interactions between gastric anatomy, motility, gut hormones, and the microbiome. Gastric emptying, a key determinant of satiety and hormonal response, differs between procedures and may contribute to variability in weight loss outcomes. Hormonal adaptations and microbiome changes after ESG remain insufficiently characterized. This study adopts an integrative approach combining gastric volumetry, gastric emptying assessment, hormonal profiling, and microbiome analysis to better understand mechanisms of response and inter-individual variability after bariatric interventions. A total of 40 patients will be enrolled (20 per group), with treatment allocation determined by a multidisciplinary team. Participants will undergo serial assessments including blood sampling, standardized meal test hormone measurements, CT-based gastric volumetry, and gastric emptying scintigraphy. Endoscopic biopsies will be performed at 12 months in the ESG group, while gastroscopy in the surgical group will be performed only if clinically indicated. The study aims to improve mechanistic understanding of bariatric interventions, identify predictors of response, and support personalized therapeutic strategies in obesity management.