The purpose of this study is to confirm the mechanism of reduced response to DPP-4 inhibitor in some patients with type 2 diabetes and evaluate appropriate patients to treat with DPP-4 inhibitor
Sitagliptin, a DPP-4 inhibitor was used as an incretin enhancer in clinical practice first. In clinical trials, sitagliptin showed effective control of blood glucose level in type 2 diabetes and 100 mg once daily with metformin was similar to sulfonylurea (glipizide) with metformin in lowering HbA1c. Mostly in practice, stable blood glucose levels were maintained after change of sulfonylurea to sitagliptin in type 2 diabetes treatment. However, in some cases, there were abrupt severe hyperglycemia and uncontrolled blood glucose level after drug change to sitagliptin. Several mechanism could be considered for reduced response to DPP-4 inhibitor in some type 2 diabetes patients. Firstly, significantly reduced secretion of glucagon-like peptide 1 (GLP-1) more than expected in diabetes or functional defect of GLP-1 activity could be the mechanism of loss of GLP-1 effect irrespective of DPP-4. Secondly, mutation or functional defect of DPP-4 enzyme could not be inhibited by DPP-4 inhibitor. Thirdly, GLP-1 receptor mutation or other defect in β-cell responsiveness to GLP-1 leads to reduction of response to DPP-4 inhibitor.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
24
Sitagliptin (100mg, per oral) once a day.
The Catholic University of Korea; St.Paul's Hospital
Seoul, South Korea
The Catholic University of Korea; Seoul St. Mary's Hospital
Seoul, South Korea
Plasma Concentration of Active Glucagon-like Peptide 1 (GLP-1) Before and After Sitagliptin Treatment
Plasma concentrations of active GLP-1 were measured at 0, 15, 30, 45, 60, 90, 120 and 180 min during the meal tolerance test (MTT). Second measurement of active GLP-1 were measured with MTT after taking sitagliptin 100 mg 1 hour before the test.
Time frame: 0, 15, 30, 45, 60, 90, 120, 180 min pre and post-dose
Plasma Concentration of Total GLP-1 Before and After Sitagliptin Treatment
Plasma concentrations of total GLP-1 were measured at 0, 15, 30, 45, 60, 90, 120 and 180 min during the meal tolerance test. Second measurement of total GLP-1 were measured with MTT after taking sitagliptin 100 mg 1 hour before the test.
Time frame: 0, 15, 30, 45, 60, 90, 120, 180 min pre and post-dose
Plasma Concentration of Total Glucose-dependent Insulinotropic Polypeptide (GIP) Before and After Sitagliptin Treatment
Plasma concentrations of total GIP were measured at 0, 15, 30, 45, 60, 90, 120 and 180 min during the meal tolerance test. Second measurement of total GIP were measured with MTT after taking sitagliptin 100 mg 1 hour before the test.
Time frame: 0, 15, 30, 45, 60, 90, 120, 180 min pre and post-dose
Change in AUC of Active GLP-1, Total GLP-1 and Total GIP Between Before and After Sitagliptin Treatment
Plasma concentrations of active GLP-1, total GLP-1 and total GIP were measured at 0, 15, 30, 45, 60, 90, 120 and 180 min during the meal tolerance test. Second measurements were measured with MTT after taking sitagliptin 100 mg 1 hour before the test. Comparisons were made using Area under the curve (AUC) values and incremental area under the curve (ΔAUC) of active GLP-1, total GLP-1 and total GIP before and after the addition of sitagliptin.
Time frame: 0, 15, 30, 45, 60, 90, 120, 180 min pre and post-dose
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Differences of DPP-4 Activity After Sitagliptin Treatment Between Responder and Non-responder Groups
The DPP-4 activity was measured at baseline and 0, 15, 30, 45 and 60 min during the meal tolerance test. Second measurement of DPP-4 activity was measured with MTT after taking sitagliptin 100 mg 1 hour before the test. Plasma DPP-4 activity during meal tolerance test is expressed as percentage activity relative to baseline. DPP-4 activity % was calculated using the following formula : (DPP-4 activity at time t / Baseline DPP-4 activity) × 100.
Time frame: 0, 15, 30, 45, 60 min post-dose