Restoration of high-frequency glucose-entrained insulin oscillations in obese subjects with type 2 diabetes after biliopancreatic diversion.

Background: Minimal glucose infusions are known to entrain insulin oscillations in patients with normal glucose tolerance (NGT) but not in patients with type 2 diabetes (T2D). Objectives: To investigate whether weight loss after a version of biliopancreatic diversion (BPD) can restore the glucose entrainment of high-frequency insulin oscillations in morbidly obese NGT or T2D patients. Setting: University Hospital, Greece. Methods: We prospectively studied 9 NGT controls (body mass index [BMI] 23.3 +/- 1.6 kg/m(2)), 9 obese NGT patients (BMI 51.1 +/- 12.7 kg/m(2)), and 9 obese T2D patients (BMI 56.8 +/- 11.6 kg/m(2)). Patients were studied before and 1.5 years after BPD. Insulin was sampled every minute for 90 minutes. Glucose (6 mg/kg weight) was infused every 10 minutes for 1 minute. Regularity of insulin pulses was estimated by autocorrelation analysis, spectral analysis, approximate entropy/sample entropy (ApEn/SampEn), and insulin pulsatility by deconvolution analysis. Results: Postoperatively, glucose and insulin concentrations of NGT and T2D patients decreased to control levels and BMI to 31.3 +/- 6.3 for NGT patients and 34.9 +/- 9.9 kg/m(2) for T2D patients. Preoperatively, glucose entrainment was absent in all T2D and in 4 NGT patients as assessed with spectral analysis and in 8 and 4, respectively, as assessed with autocorrelation and deconvolution analysis. Postoperatively, it was restored to normal in all patients. ApEn/SampEn decreased significantly only in the T2D group postoperatively. Conclusion: BPD restores the glucose entrainment of high-frequency insulin oscillations in obese NGT and T2D patients after marked weight loss and normalizes glucose levels and insulin sensitivity, thus demonstrating recovery of beta-cell glucose sensing. (C) 2016 American Society for Metabolic and Bariatric Surgery. All rights reserved.