sitagliptin-phosphate and Glucose-Intolerance

Type 2 diabetes is a very common worldwide disorder. A good glycemic control is reduce the rates of diabetes associated microvascular and possibly macrovascular complications. Dipeptidyl peptidase-4 (DPP-4) inhibitors such as sitagliptin demonstrate an incretin based, glucose-dependent actions with low risk of hypoglycemia and no weight gain during the treatment of patients with type 2 diabetes.

Topics: Administration, Oral; Blood Glucose; Cell Proliferation; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Glucose Intolerance; Humans; Hypoglycemic Agents; Insulin-Secreting Cells; Pyrazines; Sitagliptin Phosphate; Triazoles

Impaired glucose tolerance (IGT) is highly prevalent after stroke and is associated with recurrent stroke and unfavourable outcome.. We aimed to assess the feasibility, safety and effects on glucose metabolism of metformin or sitagliptin in patients with transient ischaemic attack (TIA) or minor ischaemic stroke and IGT.. We performed a multicentre, randomised, controlled, open-label phase II trial with blinded outcome assessment.. Patients were randomised in a 2:1:1 ratio to 'no medication', sitagliptin or metformin.. Primary outcome measures were baseline adjusted differences of 2-hour postload glucose; secondary outcome measures fasting glucose, glycosylated haemoglobin 1c (HbA1c) levels, tolerability and safety of metformin and sitagliptin at 6 months. Patients on metformin or sitagliptin were contacted by telephone for recording of possible adverse events and to support continuation of treatment at 2 weeks, 6 weeks and 3 months after inclusion. These events were not analysed as outcome measures.. Fifty-three patients were randomised to control group, 26 to metformin and 22 to sitagliptin. We found no significant differences in 2-hour postload glucose between patients on antidiabetic drugs and controls ((-0.04 mmol/L (95% CI -0.53 to 0.45)). Patients in the treatment arms had reduced fasting glucose: ((-0.21 mmol/L (95% CI -0.36 to -0.06)) and HbA1c levels ((-1.16 mmol/mol (95% CI -1.84 to -0.49)). Thirteen patients (50%) on metformin and 7 (32%) on sitagliptin experienced side effects. Sixteen patients (61%) in the metformin and 13 (59%) in the sitagliptin group were still on treatment after 6 months.. Metformin and sitagliptin were both effective in reducing fasting glucose and HbA1c levels in patients with recent TIA or minor ischaemic stroke and IGT. However, the reduction of glucose levels and sample size was relatively small. The clinical relevance, therefore, needs to be tempered. A phase III trial is needed to investigate whether medical treatment, compared with lifestyle intervention or a combination of both, not only improves glucose metabolism in IGT, but also leads to reduction of recurrent TIA or ischaemic stroke in these patients.. NL3048.

Topics: Blood Glucose; Brain Ischemia; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Feasibility Studies; Glucose Intolerance; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Ischemic Attack, Transient; Ischemic Stroke; Metformin; Sitagliptin Phosphate; Stroke; Treatment Outcome

Impaired incretin secretion may contribute to the defective insulin secretion and abnormal glucose tolerance (AGT) that associate with worse clinical outcomes in pancreatic insufficient cystic fibrosis (PI-CF). The study objective was to test the hypothesis that dipeptidyl peptidase-4 (DPP-4) inhibitor-induced increases in intact incretin hormone [glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)] concentrations augment insulin secretion and glucagon suppression and lower postprandial glycemia in PI-CF with AGT.. 26 adults from Children's Hospital of Philadelphia and University of Pennsylvania CF Center with PI-CF and AGT [defined by oral glucose tolerance test glucose (mg/dL): early glucose intolerance (1-h ≥ 155 and 2-h < 140), impaired glucose tolerance (2-h ≥ 140 and < 200 mg/dL), or diabetes (2-h ≥ 200)] were randomized to a 6-month double-blind trial of DPP-4 inhibitor sitagliptin 100 mg daily or matched placebo; 24 completed the trial (n = 12 sitagliptin; n = 12 placebo). Main outcome measures were mixed-meal tolerance test (MMTT) responses for intact GLP-1 and GIP, insulin secretory rates (ISRs), glucagon suppression, and glycemia and glucose-potentiated arginine (GPA) test-derived measures of β- and α-cell function.. Following 6-months of sitagliptin vs placebo, MMTT intact GLP-1 and GIP responses increased (P < 0.001), ISR dynamics improved (P < 0.05), and glucagon suppression was modestly enhanced (P < 0.05) while GPA test responses for glucagon were lower. No improvements in glucose tolerance or β-cell sensitivity to glucose, including for second-phase insulin response, were found.. In glucose intolerant PI-CF, sitagliptin intervention augmented meal-related incretin responses with improved early insulin secretion and glucagon suppression without affecting postprandial glycemia.

Topics: Adolescent; Adult; Cystic Fibrosis; Dipeptidyl-Peptidase IV Inhibitors; Double-Blind Method; Exocrine Pancreatic Insufficiency; Female; Glucagon; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin Secretion; Islets of Langerhans; Male; Sitagliptin Phosphate; Young Adult

Metformin has an established role in the management of polycystic ovary syndrome (PCOS). Some patients cannot tolerate it due to associated gastrointestinal adverse events. The present study evaluated the dipeptidyl peptidase 4 inhibitor sitagliptin as a potential treatment option in metformin-intolerant PCOS.. We conducted a 12-week, prospective, randomized, open-label study with 30 obese metformin-intolerant women with PCOS (age 35.0 ± 7.2 years; body mass index, 36.9 ± 5.5 kg/m. SITA improved beta-cell function as assessed by the homeostasis model assessment for beta-cell function index (HOMA-B) of 45.9 ± 35.8 ( P = .001), modified beta-cell function index (MBCI) of 7.9 ± 7 ( P = .002), and quantitative insulin-sensitivity check index (QUICKI) of -0.03 ± 0.03 ( P = .002). By contrast, beta-cell function decreased in CON. The between-group differences were significant for HOMA-B ( P = 0.001), MBCI ( P = .010), and QUICKI ( P = .025). The conversion rate to impaired glucose homeostasis was prevented in SITA: 3 of 15 subjects had impaired glucose tolerance (IGT) before and after the study. In CON, none had type 2 diabetes (T2D), and 4 had IGT at the beginning. After 12 weeks, IGT was observed in 2 and T2D in 3 subjects.. SITA improved beta-cell function and prevented a conversion to IGT and T2D in metformin-intolerant obese PCOS patients.. BMI = body mass index; DPP-4 = dipeptidyl peptidase-4; DXA = dual energy X-ray absorptiometry; GIP = glucose-dependent insulinotropic peptide; GLP-1 = glucagon-like peptide-1; HOMA-B = homeostasis model assessment for beta-cell function; HOMA-IR = homeostasis model assessment of insulin resistance; IAI = insulin action index; IGT = impaired glucose tolerance; IR = insulin resistance; MBCI = modified beta-cell function index; OGTT = oral glucose tolerance test; QUICKI = quantitative insulin sensitivity check index; PCOS = polycystic ovary syndrome; SHBG = sex hormone-binding globulin; T2D = type 2 diabetes.

Topics: Absorptiometry, Photon; Adult; Body Composition; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Disease Progression; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin Resistance; Insulin-Secreting Cells; Life Style; Obesity; Pilot Projects; Polycystic Ovary Syndrome; Sitagliptin Phosphate

Our pilot study examined the effectiveness of sitagliptin-metformin (SITA-MET), metformin (MET), and placebo (P) therapy on fasting and post-glucose challenge glucose levels in postpartum women with prior gestational diabetes mellitus (GDM) and impaired glucose regulation.. Prediabetic women (N = 36, age 18 to 42 years) with recent GDM were randomized to P (one pill twice a day), MET (1,000 mg twice a day), or SITA-MET (50 mg SITA, 1,000 mg MET twice a day) for 16 weeks in a single-blind fashion. An individualized diet and exercise plan were provided to all participants. At baseline and 16 weeks, oral glucose tolerance tests were performed to assess glycemia, mean blood glucose (MBG), and calculate insulin sensitivity (IS) and secretion (SI) indexes. Lipid profile, thyroid-stimulating hormone level, and pregnancy test were performed in the baseline sample.. Thirty-three (92%) participants completed the study. At study end, 15 participants had normal glycemia (SITA-MET vs. MET, P; P = .035). MBG, IS, IS-SI index, and waist to height ratio were significantly improved with SITA-MET compared with MET and P treatment. SITAMET therapy was more effective in lowering body mass index and waist circumference compared to P treatment.. Our pilot study is the first to evaluate the use of a dipeptidyl peptidase 4 inhibitor combined with MET in glucose-impaired women with a history of GDM. In this investigation, combination SITA-MET was found to be superior to MET and P in improving glycemia and metabolic measures in this prediabetic population.. BID = twice a day; BMI = body mass index; BP = blood pressure; BW = body weight; CHOL = cholesterol; DI = disposition index; DM = diabetes mellitus; DPP-4i = dipeptidyl peptidase 4 inhibitor; FBG = fasting blood glucose; GDM = gestational diabetes mellitus; GLP-1 = glucagon-like peptide 1; HDL-C = high-density-lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance; IGI = insulinogenic index; IGR = impaired glucose regulation; IGT = impaired glucose tolerance; IR = insulin resistance; IS = insulin sensitivity; LDL-C = low-density-lipoprotein cholesterol; MBG = mean blood glucose; MET = metformin; OGTT = oral glucose tolerance test; P = placebo; SI = insulin secretion; SI

Topics: Adolescent; Adult; Body Mass Index; Diabetes, Gestational; Female; Glucose Intolerance; Humans; Metformin; Pilot Projects; Placebos; Pregnancy; Prospective Studies; Single-Blind Method; Sitagliptin Phosphate; Young Adult

HIV infection is associated with a greater risk for fasting hyperinsulinemia, impaired glucose tolerance, and higher incidence rates for vascular disease, myocardial infarction, or stroke despite effective combination antiretroviral therapy (cART). The underlying mechanism(s) may involve chronic low-grade systemic inflammation and immune cell activation. Dipeptidyl peptidase-4 inhibitors (sitagliptin) improve glucose tolerance and may possess immunomodulatory effects because leukocyte CD26 cell surface receptors express dipeptidyl peptidase-4 activity.. Sitagliptin will reduce inflammatory and immune cell activation markers known to be elevated in cART-treated HIV-infected (HIV+) adults with impaired glucose tolerance.. This was designed as a prospective, randomized, placebo-controlled, double-blind trial of sitagliptin in HIV+ adults.. The setting was an academic medical center.. Patients were cART-treated HIV+ men and women (n = 36) with stable HIV disease and impaired glucose tolerance.. Interventions included sitagliptin 100 mg/d or placebo for 8 weeks.. At baseline and week 8, plasma high-sensitivity C-reactive protein and C-X-C motif chemokine 10 concentrations (ELISA), oral glucose tolerance, and abdominal sc adipose mRNA expression for M1 macrophage markers (monocyte chemotactic protein-1, EGF-like module-containing, mucin-like hormone receptor 1).. Sitagliptin reduced glucose area under the curve (P = .002) and improved oral glucose insulin sensitivity index (P = .04) more than placebo. Sitagliptin reduced plasma high-sensitivity C-reactive protein and C-X-C motif chemokine 10 levels more than placebo (P < .009). Adipose tissue monocyte chemotactic protein-1 mRNA abundance declined significantly more (P = .01), and adipose EGF-like module-containing, mucin-like hormone receptor 1 mRNA expression tended to decline more (P = .19) in sitagliptin than placebo.. Sitagliptin had beneficial systemic and adipose anti-inflammatory effects in cART-treated HIV+ adults with impaired glucose tolerance. Large-scale, long-term studies should determine whether sitagliptin reduces cardiovascular risk and events in HIV+ adults.

Topics: Adipokines; Adult; Chemokines; Endothelial Progenitor Cells; Female; Glucose Intolerance; HIV Infections; HIV-1; Humans; Hypoglycemic Agents; Inflammation; Lymphocyte Activation; Male; Middle Aged; Pyrazines; Sitagliptin Phosphate; Triazoles

To evaluate the efficacy and tolerability of sitagliptin in subjects with impaired glucose tolerance (IGT).. In a double-blind, parallel-group study, 242 Japanese subjects with IGT, determined by a 75-g oral glucose tolerance test (OGTT) at week -1, were randomized (1 : 1 : 1) to placebo (n = 83), sitagliptin 25 mg (n = 82) or 50 mg (n = 77) once daily for 8 weeks. Glycaemic variables were assessed using another OGTT at week 7 and meal tolerance tests (MTTs) at weeks 0 and 8. Primary and secondary endpoints were percent change from baseline in glucose total area under the curve 0-2 h (AUC(0 -2 h)) during the MTT and OGTT, respectively.. Least squares mean percent change from baseline in glucose AUC(0 -2 h) during the MTT were -2.4, -9.5 and -11.5%, and during the OGTT were -3.7, -21.4 and -20.1% with placebo, sitagliptin 25 mg once daily, and 50 mg once daily, respectively (p < 0.001 for either sitagliptin dose vs placebo in both tests). Sitagliptin treatment enhanced early insulin response during the OGTT and decreased total insulin response, assessed as the total AUC(0 -2 h) during the MTT. Sitagliptin treatment also suppressed glucagon response during the MTT. The incidence of adverse events, including hypoglycaemia, was low and generally similar in all treatment groups.. Treatment with sitagliptin significantly reduced glucose excursions during both an MTT and an OGTT; this effect was associated with an increase in early insulin secretion after oral glucose loading as well as a blunted glucagon response during an MTT. Sitagliptin was generally well tolerated in subjects with IGT.

Topics: Aged; Blood Glucose; Dose-Response Relationship, Drug; Double-Blind Method; Female; Glucose Intolerance; Glucose Tolerance Test; Glycemic Load; Humans; Hypoglycemic Agents; Insulin; Japan; Male; Meals; Middle Aged; Postprandial Period; Sitagliptin Phosphate

Impaired glucose tolerance is present in one third of patients with a TIA or ischemic stroke and is associated with a two-fold risk of recurrent stroke. Metformin improves glucose tolerance, but often leads to side effects. The aim of this study is to explore the feasibility, safety, and effects on glucose metabolism of metformin and sitagliptin in patients with TIA or minor ischemic stroke and impaired glucose tolerance. We will also assess whether a slow increase in metformin dose and better support and information on this treatment will reduce the incidence of side effects in these patients.. The Metformin and sitAgliptin in patients with impAired glucose tolerance and a recent TIA or minor ischemic Stroke trial (MAAS trial) is a phase II, multicenter, randomized, controlled, open-label trial with blinded outcome assessment. Non-diabetic patients (n = 100) with a recent (<6 months) TIA, amaurosis fugax or minor ischemic stroke (modified Rankin scale ≤ 3) and impaired glucose tolerance, defined as 2-hour post-load glucose levels between 7.8 and 11.0 mmol/L after repeated standard oral glucose tolerance test, will be included. Patients with renal or liver impairment, heart failure, chronic hypoxic lung disease stage III-IV, history of lactate acidosis or diabetic ketoacidosis, pregnancy or breastfeeding, pancreatitis and use of digoxin will be excluded. The patients will be randomly assigned in a 1:1:2 ratio to metformin, sitagliptin or "no treatment." Patients allocated to metformin will start with 500 mg twice daily, which will be slowly increased during a 6-week period to a twice daily dose of 1000 mg. Patients allocated to sitagliptin will be treated with a daily fixed dose of 100 mg. The study has been registered as NTR 3196 in The Netherlands Trial Register. Primary outcomes include percentage still on treatment, percentage of (serious) adverse events, and the baseline adjusted difference in 2-hour post-load glucose levels at 6 months.. This study will give more information about the feasibility and safety of metformin and sitagliptin as well as the effect on 2-hour post-load glucose levels at 6 months in patients with TIA or ischemic stroke and impaired glucose tolerance.. NTR3196 , Date of registration: 15 December 2011.

Topics: Biomarkers; Blood Glucose; Clinical Protocols; Feasibility Studies; Glucose Intolerance; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Ischemic Attack, Transient; Metformin; Netherlands; Predictive Value of Tests; Research Design; Sitagliptin Phosphate; Stroke; Time Factors; Treatment Outcome

Elevated cortisol levels and dysregulated insulin-like growth factor binding protein-1 (IGFBP-1; a marker of hepatic insulin sensitivity) are both related to insulin resistance and glucose abnormalities. It is unknown whether improvement in these parameters is related to improved glucose metabolism during treatment with sitagliptin.. To determine whether improved insulin sensitivity and beta-cell function during treatment with sitagliptin is related to lower cortisol levels and/or improved regulation of IGFBP-1 in patients with recent acute coronary syndrome (ACS) and newly discovered glucose abnormalities.. Samples were taken from The BEta-cell function in Glucose abnormalities and Acute Myocardial Infarction (BEGAMI) trial, a double-blinded, placebo-controlled randomized clinical trial on the efficacy and safety of sitagliptin for patients with ACS and newly discovered glucose abnormalities.. Cardiology departments (cardiac ICU and outpatient clinic) in two hospitals in Stockholm, Sweden.. Subjects hospitalized (or recently hospitalized) for ACS, in whom an oral glucose tolerance test revealed previously unknown glucose abnormalities.. Subjects were randomized to sitagliptin 100mg once daily (n=34) or placebo (n=37) for twelve weeks. Oral glucose tolerance test (OGTT) and randomization occurred after stabilization median 7 days after ACS.. Fasting serum cortisol and IGFBP-1 were analyzed before OGTT, around 8a.m., and after at 10a.m. The latter time point was chosen as the spread in cortisol levels around is small then, allowing improved chances to detect differences between groups.. Glucose tolerance and insulin sensitivity improved in both groups, while HbA1c and indices of β-cell function improved only in the sitagliptin group as reported previously. Both groups displayed decreased cortisol levels around 10a.m. (from 338±21 to 278±14 nmol/L, p=0.038, in the sitagliptin group; from 343±17 to 302±15 nmol/L, p=0.017, in the placebo group), and improved correlation between fasting log-IGFBP-1 and insulin.. These findings suggest that a stress-related elevation in cortisol may have negative impact on glucose tolerance in patients with recent ACS. However, improved glycemic control with sitagliptin does not appear to be related to changes in cortisol levels or hepatic insulin sensitivity as assessed by IGFBP-1.

Topics: Acute Coronary Syndrome; Aged; Aged, 80 and over; Blood Glucose; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Glucose Intolerance; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hydrocortisone; Hypoglycemic Agents; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 1; Insulin-Like Growth Factor I; Insulin-Secreting Cells; Liver; Male; Middle Aged; Myocardial Infarction; Sitagliptin Phosphate; Sweden; Treatment Outcome

Anti-inflammatory glucocorticoid (GC) therapy often induces hyperglycemia due to insulin resistance and islet-cell dysfunction. Incretin-based therapies may preserve glucose tolerance and pancreatic islet-cell function. In this study, we hypothesized that concomitant administration of the dipeptidyl peptidase-4 inhibitor sitagliptin and prednisolone in men at high risk to develop type 2 diabetes could protect against the GC-induced diabetogenic effects.. Men with the metabolic syndrome but without diabetes received prednisolone 30  mg once daily plus sitagliptin 100  mg once daily (n=14), prednisolone (n=12) or sitagliptin alone (n=14) or placebo (n=12) for 14 days in a double-blind 2 × 2 randomized-controlled study. Glucose, insulin, C-peptide, and glucagon were measured in the fasted state and following a standardized mixed-meal test. β-cell function parameters were assessed both from a hyperglycemic-arginine clamp procedure and from the meal test. Insulin sensitivity (M-value) was measured by euglycemic clamp.. Prednisolone increased postprandial area under the curve (AUC)-glucose by 17% (P<0.001 vs placebo) and postprandial AUC-glucagon by 50% (P<0.001). Prednisolone reduced 1st and 2nd phase glucose-stimulated- and combined hyperglycemia-arginine-stimulated C-peptide secretion (all P ≤ 0.001). When sitagliptin was added, both clamp-measured β-cell function (P=NS for 1st and 2nd phase vs placebo) and postprandial hyperglucagonemia (P=NS vs placebo) remained unaffected. However, administration of sitagliptin could not prevent prednisolone-induced increment in postprandial glucose concentrations (P<0.001 vs placebo). M-value was not altered by any treatment.. Fourteen-day treatment with high-dose prednisolone impaired postprandial glucose metabolism in subjects with the metabolic syndrome. Concomitant treatment with sitagliptin improved various aspects of pancreatic islet-cell function, but did not prevent deterioration of glucose tolerance by GC treatment.

Topics: Blood Glucose; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Double-Blind Method; Fasting; Glucocorticoids; Glucose Intolerance; Humans; Insulin Resistance; Islets of Langerhans; Male; Metabolic Syndrome; Middle Aged; Postprandial Period; Prednisolone; Pyrazines; Sitagliptin Phosphate; Triazoles

Newly detected impaired glucose tolerance (IGT) or type 2 diabetes mellitus (T2DM) are common in patients with acute coronary syndrome (ACS; i.e. unstable angina/myocardial infarction) and related to disturbed beta-cell function. The aim of this study is to test the hypothesis that treatment with a dipeptidyl peptidase-4 inhibitor initiated soon after a coronary event improves beta-cell function.. Acute coronary syndrome ACS patients with IGT or T2DM (n = 71), screened by oral glucose tolerance test (OGTT) 4-23 days (median 6 days) after hospital admission, were randomly assigned to sitagliptin 100 mg (n = 34) or placebo (n = 37) and treated for a duration of 12 weeks. All patients received lifestyle advice but no glucose-lowering agents other than the study drug. The study end-point was beta-cell function assessed using the insulinogenic index (IGI = ΔInsulin30 /ΔGlucose30 ), derived from an OGTT, and acute insulin response to glucose (AIRg) assessed by a frequently sampled intravenous glucose tolerance test.. The IGI and AIRg did not differ at baseline between the sitagliptin and placebo groups (69.9 vs. 66.4 pmol mmol(-1) and 1394 vs. 1106 pmol L(-1) min(-1) respectively). After 12 weeks, the IGI was 85.0 in the sitagliptin and 58.1 pmol/mmol in the placebo group (P = 0.013) and AIRg was 1909 and 1043 pmol L(-1) min(-1) (P < 0.0001) in the sitagliptin and placebo groups respectively. Fasting glucose at baseline was 6.1 mmol L(-1) in sitagliptin-treated patients and 6.0 mmol L(-1) in those who received placebo compared with 5.8 and 5.9 mmol L(-1) respectively, after 12 weeks of treatment. Post load glucose metabolism improved in significantly more sitagliptin-treated patients compared with the placebo group (P = 0.003). Sitagliptin was well tolerated.. Sitagliptin improved beta-cell function and glucose perturbations in patients with ACS and newly diagnosed glucose disturbances.

Topics: Acute Coronary Syndrome; Blood Glucose; Diabetes Mellitus, Type 2; Double-Blind Method; Follow-Up Studies; Glucagon-Like Peptide 1; Glucose Intolerance; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin-Secreting Cells; Prospective Studies; Pyrazines; Sitagliptin Phosphate; Treatment Outcome; Triazoles

Low glucagon-like peptide-1 (GLP-1) concentrations have been observed in impaired fasting glucose (IFG). It is uncertain whether these abnormalities contribute directly to the pathogenesis of IFG and impaired glucose tolerance. Dipeptidyl peptidase-4 (DPP-4) inhibitors raise incretin hormone concentrations enabling an examination of their effects on glucose turnover in IFG.. We studied 22 subjects with IFG using a double-blinded, placebo-controlled, parallel-group design. At the time of enrollment, subjects ate a standardized meal labelled with [1-(13)C]-glucose. Infused [6-(3)H] glucose enabled measurement of systemic meal appearance (MRa). Infused [6,6-(2)H(2)] glucose enabled measurement of endogenous glucose production (EGP) and glucose disappearance (Rd). Subsequently, subjects were randomized to 100 mg of sitagliptin daily or placebo. After an 8-week treatment period, the mixed meal was repeated.. As expected, subjects with IFG who received placebo did not experience any change in glucose concentrations. Despite raising intact GLP-1 concentrations, treatment with sitagliptin did not alter either fasting or postprandial glucose, insulin or C-peptide concentrations. Postprandial EGP (18.1 +/- 0.7 vs 17.6 +/- 0.8 micromol/kg per min, P = 0.53), Rd (55.6 +/- 4.3 vs 58.9 +/- 3.3 micromol/kg per min, P = 0.47) and MRa (6639 +/- 377 vs 6581 +/- 316 micromol/kg per 6 h, P = 0.85) were unchanged. Sitagliptin was associated with decreased total GLP-1 implying decreased incretin secretion.. DPP-4 inhibition did not alter fasting or postprandial glucose turnover in people with IFG. Low incretin concentrations are unlikely to be involved in the pathogenesis of IFG.

Topics: Blood Glucose; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Double-Blind Method; Fasting; Female; Glucose Intolerance; Humans; Incretins; Male; Middle Aged; Placebos; Postprandial Period; Pyrazines; Sitagliptin Phosphate; Triazoles

The aim of the present study was to demonstrate the role of autophagy and incretins in the fructose-induced alteration of β-cell mass and function. Normal Wistar rats were fed (3 weeks) with a commercial diet without (C) or with 10% fructose in drinking water (F) alone or plus sitagliptin (CS and FS) or exendin-4 (CE and FE). Serum levels of metabolic/endocrine parameters, β-cell mass, morphology/ultrastructure and apoptosis, vacuole membrane protein 1 (VMP1) expression and glucose-stimulated insulin secretion (GSIS) were studied. Complementary to this, islets isolated from normal rats were cultured (3 days) without (C) or with F and F + exendin-4 or chloroquine. Expression of autophagy-related proteins [VMP1 and microtubule-associated protein light chain 3 (LC3)], apoptotic/antiapoptotic markers (caspase-3 and Bcl-2), GSIS and insulin mRNA levels were measured. F rats developed impaired glucose tolerance (IGT) and a significant increase in plasma triacylglycerols, thiobarbituric acid-reactive substances, insulin levels, homoeostasis model assessment (HOMA) for insulin resistance (HOMA-IR) and β-cell function (HOMA-β) indices. A significant reduction in β-cell mass was associated with an increased apoptotic rate and morphological/ultrastructural changes indicative of autophagic activity. All these changes were prevented by either sitagliptin or exendin-4. In cultured islets, F significantly enhanced insulin mRNA and GSIS, decreased Bcl-2 mRNA levels and increased caspase-3 expression. Chloroquine reduced these changes, suggesting the participation of autophagy in this process. Indeed, F induced the increase of both VMP1 expression and LC3-II, suggesting that VMP1-related autophagy is activated in injured β-cells. Exendin-4 prevented islet-cell damage and autophagy development. VMP1-related autophagy is a reactive process against F-induced islet dysfunction, being prevented by exendin-4 treatment. This knowledge could help in the use of autophagy as a potential target for preventing progression from IGT to type 2 diabetes mellitus.

Topics: Animals; Autophagy; Body Weight; Cells, Cultured; Diet; Drug Evaluation, Preclinical; Energy Intake; Exenatide; Fructose; Glucose Intolerance; Glucose Tolerance Test; Hypoglycemic Agents; Incretins; Insulin; Insulin-Secreting Cells; Male; Membrane Proteins; Microscopy, Electron; Peptides; Rats, Wistar; RNA, Messenger; Sitagliptin Phosphate; Venoms

Background. Emerging evidences have shown a close interplay between obesity, diabetes, and intestinal flora disturbance. Dipeptidyl peptidase-4 inhibitor, exemplified by sitagliptin, is highly efficacious in treating type 2 diabetes (T2DM), yet little is known if sitagliptin exerts beneficial effects on microbiota associated with obesity and T2DM. We evaluated changes of gut microbiota following the induction of obesity and T2DM in a streptozotocin treated high fat/high carbohydrate fed (HF/HC-STZ) rat model and explored the effect of sitagliptin on gut microbiota for HF/HC-STZ rats. Methods. Sitagliptin was administered via oral gavage to diabetic rats. Fecal DNA extraction and 454 pyrosequencing based on analysis of 16S rRNA genes was utilized to determine the overall structure of microbiota in fecal DNA samples. Results. Results showed that, at the level of phylum, there was higher abundance of Firmicutes and Tenericutes and less abundance of Bacteroidetes in obese rats compared to their lean counterparts. At the level of genus, short-chain fatty acid- (SCFA-) producing bacteria, Blautia, Roseburia, and Clostridium, and probiotics Lactobacillus, Bifidobacterium, and so forth were identified significantly different from each other among conditions. Conclusion. Marked shifts of the gut microbiota structure were observed in the rats during development of glucose intolerance. Intestinal flora changed in the process of glucose intolerance, and treatment of sitagliptin moderately corrected the dysbiosis of microbiota in T2DM.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Complications; Disease Progression; Gastrointestinal Microbiome; Glucose Intolerance; Hypoglycemic Agents; Rats; Sitagliptin Phosphate

We tested the exendin-4 and des-fluoro-sitagliptin effects on fructose-induced increase in liver glucokinase activity in rats with impaired glucose tolerance and the exendin-4 effect on glucokinase activity in HepG2 cells incubated with fructose in the presence/absence of exendin-9-39. After 3 weeks of in vivo fructose administration we measured: (1) serum glucose, insulin and triglyceride levels; (2) liver and HepG2 cells glucokinase activity and (3) liver glucokinase and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase mRNA and protein levels. Fructose fed rats had: hypertriglyceridemia, hyperinsulinemia and high liver glucokinase activity (mainly located in the cytosolic fraction) together with higher glucokinase and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase mRNA and protein concentrations compared to control rats. Co-administration of either exendin-4 or des-fluoro-sitagliptin prevented serum and liver changes except glucokinase protein expression. Exendin-4 also prevented fructose-induced increase in glucokinase activity in cultured HepG2 cells, effect blunted by co-incubation with exendin-9-36. In conclusion exendin-4/des-fluro-sitagliptin prevented fructose-induced effect on glucokinase activity, mainly affecting enzyme activity modulators. Exendin 9-39 blunted in vitro protective exendin-4 effect on glucokinase activity, thus suggesting a direct effect of the later on hepatocytes through GLP-1 receptor. Alterations of glucokinase activity modulators could play a role in the pathogenesis of liver dysfunction, becoming a potential new treatment target for GLP-1 receptor agonists.

Topics: Animals; Exenatide; Fructose; Gene Expression; Glucokinase; Glucose Intolerance; Hep G2 Cells; Humans; Incretins; Liver; Male; Peptides; Rats; Rats, Wistar; Sitagliptin Phosphate; Venoms

Myocardial fibrosis is a key process in diabetic cardiomyopathy. However, their underlying mechanisms have not been elucidated, leading to a lack of therapy. The glucagon-like peptide-1 (GLP-1) enhancer, sitagliptin, reduces hyperglycemia but may also trigger direct effects on the heart.. Goto-Kakizaki (GK) rats developed type-II diabetes and received sitagliptin, an anti-hyperglycemic drug (metformin) or vehicle (n=10, each). After cardiac structure and function assessment, plasma and left ventricles were isolated for biochemical studies. Cultured cardiomyocytes and fibroblasts were used for in vitro assays.. Untreated GK rats exhibited hyperglycemia, hyperlipidemia, plasma GLP-1 decrease, and cardiac cell-death, hypertrophy, fibrosis and prolonged deceleration time. Moreover, cardiac pro-apoptotic/necrotic, hypertrophic and fibrotic factors were up-regulated. Importantly, both sitagliptin and metformin lessened all these parameters. In cultured cardiomyocytes and cardiac fibroblasts, high-concentration of palmitate or glucose induced cell-death, hypertrophy and fibrosis. Interestingly, GLP-1 and its insulinotropic-inactive metabolite, GLP-1(9-36), alleviated these responses. In addition, despite a specific GLP-1 receptor was only detected in cardiomyocytes, GLP-1 isoforms attenuated the pro-fibrotic expression in cardiomyocytes and fibroblasts. In addition, GLP-1 receptor signalling may be linked to PPARδ activation, and metformin may also exhibit anti-apoptotic/necrotic and anti-fibrotic direct effects in cardiac cells.. Sitagliptin, via GLP-1 stabilization, promoted cardioprotection in type-II diabetic hearts primarily by limiting hyperglycemia e hyperlipidemia. However, GLP-1 and GLP-1(9-36) promoted survival and anti-hypertrophic/fibrotic effects on cultured cardiac cells, suggesting cell-autonomous cardioprotective actions.

Topics: Animals; Apoptosis; Cardiomegaly; Cardiotonic Agents; Cells, Cultured; Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Disease Models, Animal; Drug Evaluation, Preclinical; Fibroblasts; Fibronectins; Fibrosis; Glucagon-Like Peptide 1; Glucose Intolerance; Hypoglycemic Agents; Insulin; Male; Metformin; Myocardium; Myocytes, Cardiac; PPAR delta; Protein Isoforms; Pyrazines; Rats; Sitagliptin Phosphate; Triazoles

In this study, we combined the dipeptidyl peptidase-4 inhibitor sitagliptin with the antidiabetic drug mangiferin to examine the effects on active glucagon-like peptide-1 (GLP-1) and glucose tolerance in streptozotocin-diabetic rats. Active GLP-1 levels were measured by an ELISA kit. Insulin levels were measured by an RIA kit. Islet morphology was determined by double immunolabeling. Sitagliptin (1 mg/kg) or mangiferin (20 mg/kg) single treatment improved glucose tolerance during an oral glucose tolerance test. In addition, the combination therapy improved glucose tolerance with an increase in plasma insulin level and active GLP-1 levels. Islets from combination-treated diabetic rats had markedly increased β-cell/islet area ratio compared with islets from the diabetic or single-treatment rats. In conclusion, these results indicate that the combination therapy is useful as a therapeutic agent for impaired glucose tolerance and type 2 diabetes.

Topics: Animals; Diabetes Mellitus, Experimental; Dipeptidyl-Peptidase IV Inhibitors; Drug Therapy, Combination; Glucagon-Like Peptide 1; Glucose Intolerance; Insulin; Islets of Langerhans; Male; Pyrazines; Rats; Rats, Sprague-Dawley; Sitagliptin Phosphate; Streptozocin; Triazoles; Xanthones

Adipose tissue inflammation and reduced pancreatic β-cell function are key issues in the development of cardiovascular disease and progressive metabolic dysfunction in type 2 diabetes mellitus. The aim of this study was to determine the effect of the DPP IV inhibitor sitagliptin on adipose tissue and pancreatic islet inflammation in a diet-induced obesity model. C57Bl/6J mice were placed on a high-fat (60% kcal fat) diet for 12 wk, with or without sitagliptin (4 g/kg) as a food admix. Sitagliptin significantly reduced fasting blood glucose by 21% as well as insulin by ∼25%. Sitagliptin treatment reduced body weight without changes in overall body mass index or in the epididymal and retroperitoneal fat mass. However, sitagliptin treatment led to triple the number of small adipocytes despite reducing the number of the very large adipocytes. Sitagliptin significantly reduced inflammation in the adipose tissue and pancreatic islet. Macrophage infiltration in adipose tissue evaluated by immunostaining for Mac2 was reduced by sitagliptin (P < 0.01), as was the percentage of CD11b+/F4/80+ cells in the stromal vascular fraction (P < 0.02). Sitagliptin also reduced adipocyte mRNA expression of inflammatory genes, including IL-6, TNFα, IL-12(p35), and IL-12(p40), 2.5- to fivefold as well as 12-lipoxygenase protein expression. Pancreatic islets were isolated from animals after treatments. Sitagliptin significantly reduced mRNA expression of the following inflammatory cytokines: MCP-1 (3.3-fold), IL-6 (2-fold), IL-12(p40) (2.2-fold), IL-12(p35) (5-fold, P < 0.01), and IP-10 (2-fold). Collectively, the results indicate that sitagliptin has anti-inflammatory effects in adipose tissue and in pancreatic islets that accompany the insulinotropic effect.

Topics: Adipocytes; Adipose Tissue; Adiposity; Animals; Anti-Inflammatory Agents; Body Weight; Cytokines; Dipeptidyl-Peptidase IV Inhibitors; Flow Cytometry; Glucose; Glucose Intolerance; Glucose Tolerance Test; Immunohistochemistry; Inflammation; Insulin; Islets of Langerhans; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Neutrophil Infiltration; Pyrazines; Reverse Transcriptase Polymerase Chain Reaction; Sitagliptin Phosphate; Triazoles