Diego Moriconi

Roux-en-Y Gastric Bypass and Sleeve Gastrectomy: Mechanisms of Diabetes Remission and Role of Gut Hormones

CONTEXT In obese patients with type 2 diabetes (T2DM), Roux-en-Y-gastric-bypass (RYGB) and sleeve gastrectomy (SLG) improve glycemic control. OBJECTIVE The objective of this study was to investigate the mechanisms of surgery-induced T2DM improvement and role of gastrointestinal hormones. PATIENTS, SETTING, AND INTERVENTION: In 35 patients with T2DM, we performed a mixed-meal test before and 15 days and 1 year after surgery (23 RYGB and 12 SLG). MAIN OUTCOME MEASURES Insulin sensitivity, β-cell function, and amylin, ghrelin, PYY, pancreatic polypeptide (PP), glucagon, and glucagon-like peptide-1 (GLP-1) responses to the meal were measured. RESULTS T2DM remission occurred in 13 patients undergoing RYGB and in 7 patients undergoing SLG. Similarly in the RYGB and SLG groups, β-cell glucose sensitivity improved both early and long term (P < .005), whereas insulin sensitivity improved long term only (P < .006), in proportion to body mass index changes (P < .001). Early after RYGB, glucagon and GLP-1 responses to the meal increased, whereas the PP response decreased. At 1 year, PYY was increased, and PP, amylin, ghrelin, and GLP-1 were reduced. After SLG, hormonal responses were similar to those with RYGB except that PP was increased, whereas amylin was unchanged. In remitters, fasting GLP-1 was higher (P = .04), but its meal response was flat compared with that of nonremitters; postsurgery, however, the GLP-1 response was higher. Other hormone responses were similar between the 2 groups. In logistic regression, presurgery β-cell glucose sensitivity (positive, P < .0001) and meal-stimulated GLP-1 response (negative, P = .004) were the only predictors of remission. CONCLUSIONS RYGB and SLG have a similar impact on diabetes remission, of which baseline β-cell glucose sensitivity and a restored GLP-1 response are the chief determinants. Other hormonal responses are the consequences of the altered gastrointestinal anatomy.

Estimation of Urinary Creatinine Excretion and Prediction of Renal Function in Morbidly Obese Patients: New Tools from Body Composition Analysis

Background/Aims: In obese subjects the accuracy of prediction of renal function is quite low. The aim of this study was to obtain a more accurate estimate of urinary creatinine excretion (UCr), creatinine clearance (CCr), and GFR from body cell mass (BCM). Methods: Seventy-three adult morbidly obese patients (BMI 35.2-64.5 kg/m2) were examined. BCM was calculated from body impedance analysis. CCr was measured (mCCr) and was predicted from BCM and antropometric data (MR-BCMCCr), with Cockcroft and Gault (C&GCCr) and Salazar and Corcoran (S&CCCr) formulas. GFR was predicted from BCM (BCM GFR) and with MDRD and CKD-EPI formulas. Results: Multiple regression (MR) indicated a strict linear correlation between UCr, BCM and anthropometric data. UCr predicted from MR equation (MR-BCMUCr) was very similar to measured UCr. MR-BCMCCr (168±46 mL/min) and mCCr (167±51 mL/min) were also similar, while significant differences were found between mCCr, C&GCCr and S&CCCr. The correlation and the agreement between MR-BCMCCr and mCCr were closer and prediction error was lower than the other formulas. BCM GFR (125±32 mL/min) had close correlations and agreements with MDRD GFR and CKD EPI formulas. Conclusions: In morbidly obese patients the measurement of BCM meliorates the prediction of UCr and CCr, and allows the prediction of GFR.