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Treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin improves fasting islet-cell function in subjects with type 2 diabetes.

ABSTRACT: Dipeptidyl peptidase 4 (DPP-4) inhibitors are proposed to lower blood glucose in type 2 diabetes mellitus (T2DM) by prolonging the activity of the circulating incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1). Consistent with this mechanism of action, DPP-4 inhibitors improve glucose tolerance after meals by increasing insulin and reducing glucagon levels in the plasma. However, DPP-4 inhibitors also reduce fasting blood glucose, an unexpected effect because circulating levels of active GIP and GLP-1 are low in the postabsorptive state.The objective of the study was to examine the effects of DPP-4 inhibition on fasting islet function.We conducted a randomized, double-blind, placebo-controlled trial.The study was performed in General Clinical Research Centers at two University Hospitals.Forty-one subjects with T2DM were treated with metformin or diet, having good glycemic control with glycosylated hemoglobin values of 6.2-7.5%.Subjects were treated with vildagliptin (50 mg twice daily) or placebo for 3 months, followed by a 2-wk washout. Major Outcome Measure: We measured insulin secretion in response to iv glucose and arginine before and after treatment and after drug washout.There were small and comparable reductions in glycosylated hemoglobin in both groups over 3 months. Vildagliptin increased fasting GLP-1 levels in subjects taking metformin, but not those managed with diet, and raised active GIP levels slightly. DPP-4 inhibitor treatment improved the acute insulin and C-peptide responses to glucose (50 and 100% respectively; P < 0.05) and increased the slope of the C-peptide response to glucose (33%; P = 0.023).Vildagliptin improves islet function in T2DM under fasting conditions. This suggests that DPP-4 inhibition has metabolic benefits in addition to enhancing meal-induced GLP-1 and GIP activity.

SUBMITTER: D'Alessio DA

PROVIDER: S-EPMC2630874 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature

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Treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin improves fasting islet-cell function in subjects with type 2 diabetes.

D'Alessio David A DA Denney Amanda M AM Hermiller Linda M LM Prigeon Ronald L RL Martin Julie M JM Tharp William G WG Saylan Monica Liqueros ML He Yanling Y Dunning Beth E BE Foley James E JE Pratley Richard E RE

The Journal of clinical endocrinology and metabolism 20081028 1

<h4>Context</h4>Dipeptidyl peptidase 4 (DPP-4) inhibitors are proposed to lower blood glucose in type 2 diabetes mellitus (T2DM) by prolonging the activity of the circulating incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1). Consistent with this mechanism of action, DPP-4 inhibitors improve glucose tolerance after meals by increasing insulin and reducing glucagon levels in the plasma. However, DPP-4 inhibitors also reduce fasting blood glucose, an ...[more]

PMID: 18957505

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Project description:IntroductionSaxagliptin, sitagliptin, and vildagliptin are dipeptidyl peptidase-4 (DPP-4) inhibitors widely approved for use in patients with type 2 diabetes. Using a crossover design, the present study compared trough levels of DPP-4 inhibition provided by these agents in a single cohort of patients with type 2 diabetes.MethodsThis was a randomized, placebo-controlled, open-label, five-period crossover study. Eligible patients were 18-65 years of age, either treatment-naïve or off prior antihyperglycemic agent therapy for at least 6 or 12 weeks (depending on the prior therapy), and had glycated hemoglobin (HbA1C) ≥6.5% and ≤10.0%. In separate study periods, patients received 5 mg saxagliptin q.d. (saxa-5), 100 mg sitagliptin q.d. (sita-100), 50 mg vildagliptin q.d. (vilda-50-q.d.), 50 mg vildagliptin b.i.d. (vilda-50-b.i.d.), or placebo for 5 days. The primary endpoint was trough %DPP-4 inhibition, derived by comparing DPP-4 activity 24 h after the Day-5 morning dose with predose activity in the same period and analyzed using a linear mixed-effects model with fixed-effects terms for treatment and period.ResultsMean (range) baseline HbA1C was 7.4% (6.4-9.0%; N = 22). Least-squares (LS) mean trough %DPP-4 inhibition was 73.5%, 91.7%, 28.9%, 90.6%, and 3.5% after saxa-5, sita-100, vilda-50-q.d., vilda-50-b.i.d., and placebo, respectively. In patients treated with sita-100, the LS-mean difference in trough %DPP-4 inhibition was 18.2% greater than with saxa-5 (p < 0.001), 62.9% greater than with vilda-50-q.d. (p < 0.001), 1.1% greater than with vilda-50-b.i.d. (p = 0.128), and 87.8% greater than with placebo (p < 0.001). Mean %DPP-4 inhibition was nearly maximal at 12 h postdose regardless of active treatment. Thus, these between-group comparisons at trough primarily reflected differences in duration of action. Adverse events reported during the study were transient and mild or moderate in intensity.ConclusionOnce daily treatment with sitagliptin provided trough DPP-4 inhibition significantly greater than saxagliptin or vildagliptin administered once daily, and similar to that provided by vildagliptin administered twice daily.

Project description:Objective: We recently observed a greater increase in plasma levels of bioactive glucose-dependent insulinotropic polypeptide (GIP) than glucagon-like peptide 1 (GLP-1) using the receptor-mediated bioassays in the subjects with normal glycemic tolerance (NGT) treated with dipeptidyl peptidase 4 (DPP-4) inhibitors, which may be unappreciated using conventional enzyme-linked immunosorbent assays (ELISAs) during oral glucose tolerance test. Thus, we determined incretin levels in addition to glucagon level using the bioassays in type 2 diabetes mellitus (T2DM) subjects with or without treatment of DPP-4 inhibitor, to evaluate whether these assays can accurately measure bioactivity of these peptides. Methods: We performed single meal tolerance test (MTT) by using a cookie meal (carbohydrate 75.0 g, protein 8.0 g, fat 28.5 g) in the subjects with NGT (n = 9), the subjects with T2DM treated without DPP-4 inhibitor (n = 7) and the subjects with T2DM treated with DPP-4 inhibitor (n = 10). All subjects fasted for 10-12 h before the MTT, and blood samples were collected at 0, 30, 60, and 120 min. We used the cell lines stably cotransfected with human-form GIP, GLP-1 or glucagon receptor, and a cyclic adenosine monophosphate-inducible luciferase expression construct for the bioassays. We measured active GIP, active GLP-1, and glucagon by the bioassays. To evaluate the efficacy of bioassay, we measured identical samples via ELISA kits. Results: During the single MTT study, postprandial active GIP bioassay levels of T2DM with DPP-4 inhibitor treatment were drastically higher than those of NGT and T2DM without DPP-4 inhibitor, although the DPP-4 inhibitor-treated group showed moderate increase of active GIPELISA and active GLP-1 bioassay , while active GLP-1 bioassay levels of T2DM subjects without DPP-4 inhibitor were comparable to those of NGT subjects. During the serial MTT, administration of DPP-4 inhibitor significantly increased active GIP bioassay levels, but not active GLP-1 bioassay . Conclusions: In comparison to conventional ELISA, receptor-mediated bioassay reflects dynamic change of GIP polypeptide by DPP-4 inhibitor treatment in subjects with type 2 diabetes.

Dataset Information

Treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin improves fasting islet-cell function in subjects with type 2 diabetes.

Publications

Treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin improves fasting islet-cell function in subjects with type 2 diabetes.

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