Aim: To measure Urocortin3 (Ucn3) blood levels in morbidly obese (MO) non diabetic patients before and after laparoscopic sleeve gastrectomy (LSG) for excess body weight reduction and explore its relationship with b-cell function. Ucn3 is involved in insulin secretion in the presence of nutrient excess, a key feature of obesity, and may be an integral part of the compensation of β-cells function.
Methods: Nine MO patients who underwent LSG and 11 healthy non-obese subjects (HS) were studied. MO and HS had, preoperatively and 6 months postoperatively, a 2-hour, 75 g oral glucose tolerance test (OGTT). Blood samples were withdrawn at 0, 30, 60, 90 and 120 minutes for glucose, insulin, lipid levels measurements and for Ucn3 levels at 0 and 60 minutes. HOMAR, Matsuda index, insulinogenic index and desposition index were also calculated.
Results: In MO, six months after the operation, mean BMI and waist circumference decreased significantly (from 44.7 to 30.5 Kg/m2 and 130.8 to 99.2 cm, respectively). Blood Ucn3 levels in MO decreased significantly 6 months after LSG (24.45±9.42 vs 3.66±2.71 pg/dl; P=0.001), down to levels similar to HS. Body weight reduction was followed by significant decline of fasting serum glucose and insulin levels (94.9+10.3 to 82.9+4.9 P=0.013 and 25.6+16.4 to 6.5+2.4 P=0.001) and their areas under the curve (17.288+3.625 to 13.588+2.965 P=0.048 and 12.947+5.176 to 6.714+3.039 P=0.001, respectively). Insulin sensitivity increased significantly (P=0.001), but first phase insulin release and b-cell function remained unchanged. Ucn3 concentrations were positively associated with insulin, BMI, HOMAR and triglycerides levels. However, in multiple regression analysis BMI was the only predictor.
Conclusion: Blood Ucn3 levels are significantly higher in obese non-diabetic subjects with hyperinsulinemia and insulin resistance. Reduction of excess body weight is followed by a parallel decrease of insulin and Ucn3 blood levels.