GDF15 and Cortisol Response to Meal Tolerance Test in Post-Sleeve Gastrectomy Patients with Weight Regain

Background Hormonal factors behind weight regain (WR) after surgical weight loss remain inadequately understood. Growth/differentiation factor 15 (GDF15) has emerged as a potential therapeutic target in obesity treatment. Cortisol, another stress hormone, has also been associated with weight gain at both low and high circulating concentrations. We aimed to compare meal-stimulated GDF15 and cortisol response in adults with and without WR after sleeve gastrectomy (SG). We hypothesized that GDF15 and cortisol response to meal tolerance test (MTT) will be lower in those with versus without WR after SG. Methods Cross-sectional study comprised 21 adults without diabetes, who underwent SG. WR was defined as 100 x (current weight - nadir)/(preoperative weight - nadir) > 10%. GDF15, cortisol, insulin, glucose, and incretins (total glucagon-like peptide (GLP)-1 and glucose-dependent insulinotropic polypeptide (GIP) circulating concentrations) were measured during MTT (0-240 min) after 3-6 years post-bariatric surgery. Results All participants were 48% White, 85% female, with mean (SD) age: 43(10) years, and BMI: 36.2(7.6) kg/m(2). Compared to the non-WR group (n = 6), the WR group (n = 15) had significantly higher BMI (WR: 38.6 +/- 7.6 kg/m(2), non-WR: 30.3 +/- 3.5 kg/m(2), p = 0.02) and showed lower GDF15 response (WR AUC vs non-WR AUC (116143 +/- 13973 vs 185798 +/- 38884 ng*min/L, p = 0.047)) and lower cortisol response (WR AUC vs non-WR AUC (3492 +/- 210 vs 4880 +/- 655 mu g*min/dL, p = 0.015)). Incretin response did not differ between the groups. Conclusions GDF15 and cortisol responses to MTT were lower in those who regained the weight after SG compared to those who did not, suggesting that dysregulation in GDF15 and cortisol response following bariatric surgery.