Resumen de Effects of a D-Xylose Preload With or Without Sitagliptin on Gastric Emptying, Glucagon-Like Peptide-1, and Postprandial Glycemia in Type 2 Diabetes
Tongzhi Wu, Michelle Bound, Beiyi R. Zhao, Scott D. Standfield, Max Bellon, Karen L. Jones, Michael Horowitz, Christopher K. Rayner
Macronutrient "preloads" can reduce postprandial glycemia by slowing gastric emptying and stimulating glucagon-like peptide-1 (GLP-1) secretion. An ideal preload would entail minimal additional energy intake and might be optimized by concurrent inhibition of dipeptidyl peptidase-4 (DPP-4). We evaluated the effects of a low-energy D-xylose preload, with or without sitagliptin, on gastric emptying, plasma intact GLP-1 concentrations, and postprandial glycemia in type 2 diabetes. Twelve type 2 diabetic patients were studied on four occasions each. After 100 mg sitagliptin (S) or placebo (P) and an overnight fast, patients consumed a preload drink containing either 50 g D-xylose (X) or 80 mg sucralose control [C]), followed after 40 min by a mashed potato meal labeled with ^sup 13^C-octanoate. Blood was sampled at intervals. Gastric emptying was determined. Both peak blood glucose and the amplitude of glycemic excursion were lower after PX and SC than PC (P < 0.01 for each) and were lowest after SX (P < 0.05 for each), while overall blood glucose was lower after SX than PC (P < 0.05). The postprandial insulin-to-glucose ratio was attenuated (P < 0.05) and gastric emptying was slower (P < 0.01) after D-xylose, without any effect of sitagliptin. Plasma GLP-1 concentrations were higher after D-xylose than control only before the meal (P < 0.05) but were sustained postprandially when combined with sitagliptin (P < 0.05). In type 2 diabetes, acute administration of a D-xylose preload reduces postprandial glycemia and enhances the effect of a DPP-4 inhibitor.
