Effects of a D-xylose preload with or without sitagliptin on gastric emptying, glucagon-like peptide-1, and postprandial glycemia in type 2 diabetes.
OBJECTIVE
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.


METHODS
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 (13)C-octanoate. Blood was sampled at intervals. Gastric emptying was determined.


RESULTS
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).


CONCLUSIONS
In type 2 diabetes, acute administration of a D-xylose preload reduces postprandial glycemia and enhances the effect of a DPP-4 inhibitor.
Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia.
Tongzhi
T
Wu
Michelle J
MJ
Bound
Beiyi R
BR
Zhao
Scott D
SD
Standfield
Max
M
Bellon
Karen L
KL
Jones
Michael
M
Horowitz
Christopher K
CK
Rayner
D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D011719:Pyrazines / Q000627:therapeutic use*; D011863:Radioimmunoassay; D000068900:Sitagliptin Phosphate; D014230:Triazoles / Q000627:therapeutic use*; D014994:Xylose / Q000627:therapeutic use*
D001786:Blood Glucose; D054873:Dipeptidyl-Peptidase IV Inhibitors; D007328:Insulin; D011719:Pyrazines; D014230:Triazoles; D052216:Glucagon-Like Peptide 1; D014994:Xylose; D000068900:Sitagliptin Phosphate