title: Effects of saxagliptin on β-cell stimulation and insulin secretion in patients with type 2 diabetes.
abstract: OBJECTIVE
  To study the effect of dipeptidyl peptidase-4 (DPP-4) inhibition with saxagliptin on β-cell function as reflected by the stimulated insulin secretion rate after an enteral glucose load in patients with type 2 diabetes.
  
  
  METHODS
  Patients in this randomized, parallel-group, double-blind, placebo-controlled study were drug-naïve, aged 43-69 years, with baseline haemoglobin A1c (HbA1c) 5.9-8.1%. Twenty patients received saxagliptin 5 mg once daily; 16 received placebo. Patients were assessed at baseline and week 12 by intravenous hyperglycaemic clamp (0-180 min, fasting state), and intravenous-oral hyperglycaemic clamp (180-480 min, postprandial state) following oral ingestion of 75 g glucose. Primary and secondary endpoints were percent changes from baseline in insulin secretion during postprandial and fasting states, respectively. Insulin secretion was calculated by C-peptide deconvolution.
  
  
  RESULTS
  After 12 weeks, saxagliptin significantly increased insulin secretion percent change from baseline during the postprandial state by an 18.5% adjusted difference versus placebo (p = 0.04), an improvement associated with increased peak plasma concentrations of intact glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. In the fasting state, saxagliptin significantly increased insulin secretion by a 27.9% adjusted difference versus placebo (p = 0.02). Saxagliptin also improved glucagon area under the curve in the postprandial state (adjusted difference -21.8% vs. placebo, p = 0.03).
  
  
  CONCLUSIONS
  DPP-4 inhibition with saxagliptin improves pancreatic β-cell function in postprandial and fasting states, and decreases postprandial glucagon concentration. Given the magnitude of enhancement of the insulin response in the fasting state, further study into the effect of DPP-4 inhibition on the β-cell is warranted.
authors.affiliation: VA San Diego Healthcare System Research Service and University of California San Diego School of Medicine, San Diego, CA, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Henry
authors.forename: S R
authors.initials: SR
authors.lastname: Smith
authors.forename: S L
authors.initials: SL
authors.lastname: Schwartz
authors.forename: S R
authors.initials: SR
authors.lastname: Mudaliar
authors.forename: C F
authors.initials: CF
authors.lastname: Deacon
authors.forename: J J
authors.initials: JJ
authors.lastname: Holst
authors.forename: R Y
authors.initials: RY
authors.lastname: Duan
authors.forename: R S
authors.initials: RS
authors.lastname: Chen
authors.forename: J F
authors.initials: JF
authors.lastname: List
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000187:drug effects*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D004151:Dipeptides / Q000627:therapeutic use*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000218:Adamantane; D001786:Blood Glucose; D004151:Dipeptides; D054873:Dipeptidyl-Peptidase IV Inhibitors; D006442:Glycated Hemoglobin; D007328:Insulin; C502994:saxagliptin