Effects of a combination of sitagliptin plus metformin vs metformin monotherapy on glycemic control, β-cell function and insulin resistance in type 2 diabetic patients

Comparison of teneligliptin and other gliptin-based regimens in addressing insulin resistance and glycemic control in type 2 diabetic patients: a cross-sectional study

INTRODUCTION

The objective of this study was to compare the effects of teneligliptin-based regimens and other gliptin-based regimens with respect to insulin resistance and glycemic control in patients with type 2 diabetes mellitus (T2DM).

METHODS

We enrolled T2DM subjects, inadequately controlled with metformin and glimepiride and taking one of the gliptins, and divided them into two groups, i.e. group 1 (teneligliptin-based regimens) and group 2 (other gliptin-based regimens). Fasting plasma insulin, adiponectin levels, homeostatic model assessment for insulin resistance (HOMA-IR), glycated hemoglobin (HbA1c), and fasting blood glucose (FBG) were measured and compared. Costs of different gliptins were noted, and mean cost of per day therapy was compared.

RESULTS

Eighty-six subjects participated in this study (43 each in group 1 and group 2). No significant differences were observed in FBG, HbA1c, insulin levels, and HOMA-IR, but the trend was in favor of teneligliptin-based regimens. A significantly higher number of subjects achieved HbA1c target in group 1 (P < 0.001). Teneligliptin had significantly lower cost of per day therapy as compared to other dipeptidyl peptidase-4 inhibitors.

CONCLUSION

Teneligliptin seems to be cost-effective and safer option in T2DM subjects who were not adequately controlled with metformin and sulfonylureas. However, further prospective studies are needed.

Dipeptidyl-peptidase-4 inhibitors have anti-inflammatory effects in patients with type 2 diabetes

AIMS

Systematic low-grade inflammation is considered to be an important factor leading to the development of T2DM and the progression of its complications. Dipeptidyl-peptidase-4 (DPP-4) inhibitors show potential anti-inflammatory effects in patients with T2DM. This meta-analysis aimed to evaluate the anti-inflammatory effects of DPP-4 inhibitors in patients with T2DM.

METHODS

A comprehensive search was performed in PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials to identify randomized controlled trials that assess the anti-inflammatory effects of DPP-4 inhibitors. Quantitative data analysis was conducted by a random-effects model. Sensitivity analyses were conducted to determine the robustness of the pooled results.

RESULTS

Twenty-two studies with 1595 patients with T2DM were included. Pooled results showed that DPP-4 inhibitor therapy was significantly associated with the reduction of C-reactive protein (CRP) (SMD, - 0.56, p < 0.01), TNF-α (SMD, - 1.69, p < 0.01), IL-6 (SMD, - 0.67, p < 0.01), and IL-1β (WMD, - 8.21 pg/ml, p < 0.01). Leave-one-out meta-analysis showed no significant change in the pooled results of CRP and TNF-α.

CONCLUSION

This meta-analysis demonstrated that DPP-4 inhibitors can significantly attenuate low-grade inflammatory state in patients with T2DM. In addition to improving glycemic control, DDP-4 inhibitors might offer extra therapeutic value by controlling inflammation.

Exorbitant Drug Loading of Metformin and Sitagliptin in Mucoadhesive Buccal Tablet: In Vitro and In Vivo Characterization in Healthy Volunteers

The aim of the proposed study is to develop a mucoadhesive buccal delivery system for the sustained delivery of metformin (MET) and sitagliptin (SIT) against diabetes mellitus (DM) with improved bioavailability. Polymeric blend of Carbopol® 940 (CP), agarose (AG) or polyvinylpyrrolidone K30 (PVP) as mucoadhesive agents in formulations (R1-R15) were compressed via the direct compression technique. Tablets were characterized for solid state studies, physicochemical and in vivo mucoadhesion studies in healthy volunteers. Outcomes did not reveal any unusual peak or interaction between the drugs and polymers in the physical mixture through Fourier Transform Infrared Spectroscopy (FTIR) and DSC analysis. The mucoadhesive blend of CP and PVP was superior compared to other blends. The formulation R4 revealed exorbitant loading of drugs with complete drug release for 6 h with ex vivo mucoadhesive strength and time of 26.99 g and 8.1 h, respectively. It was further scrutinized to evaluate it as an optimized formulation where it was found to be stable for up to 6 months. The formulation R4 depicted Korsmeyer-Peppas model and first-order mode of release correspondingly for SIT and MET. Moreover, it showed hemocompatibility, biocompatibility and stability with non-significant changes in the dissolution profile. Overall, the CP blend with PVP was found appropriate to yield the desired release coupled with the optimized mucoadhesive properties of the buccal tablets, ensuring sufficient pharmaceutical stability.

Effect of Metformin Intervention on Pancreatic β-Cell Apoptosis

Metformin is shown to have hypoglycemic effects. However, the relationship between metformin’s intervention in FFA-induced endoplasmic reticulum stress-mediated insulin resistance (IR) and insulin β-cell apoptosis under high-glucose condition remains unclear. Our study intends to assess their relationship. Human pancreatic β-cells were treated with metformin and cell proliferation and IR were detected by MTT assay along with detection of Wnt/β-catenin signaling by RT-PCR, cell cycle and apoptosis by flow cytometry. Metformin inhibited β cell proliferation which was mediated by FFA-induced endoplasmic reticulum stress in a time-dependent and dose-dependent manner as well as induced cell cycle arrest at G2/M phase. In addition, metformin inhibited β-catenin signaling activation and decreased the expression of c-myc, Dvl-2, survivin, Dvl-3, GSK-3β (p-ser9) and promoted GSK-3 (p-tyr216) and Axin-2 expression. In conclusion, metformin inhibits Wnt/β-catenin signaling and promotes FFA to induce endoplasmic reticulum stress, thereby mediating pancreatic β-cells behaviors.

Effects of Sitagliptin as Monotherapy and Add-On to Metformin on Weight Loss among Overweight and Obese Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis

BACKGROUND

Sitagliptin is known as an antidiabetic agent inhibiting the dipeptidyl peptidase-4. Although sitagliptin may influence weight, controversial results have been reported, and there is no general agreement on this issue. Therefore, this study assessed the effect of sitagliptin as monotherapy and add-on therapy to metformin on weight reduction in overweight or obese cases with type 2 diabetes.

METHODS

We reviewed the following databases to identify all relevant papers published until 1st April 2021: Web of Science, MEDLINE, Embase, Scopus, Cochrane Central Register of Controlled Trials Cochrane Library, and Google Scholar. The research included all clinical trials investigating the effect of sitagliptin in obese or overweight adult patients with type 2 diabetes without any language restriction.

RESULTS

In total, eighteen randomized controlled trials with 2009 participants were included in our meta-analysis. Results showed supplementation of sitagliptin has led to weight loss for sitagliptin treated (MD  -0.99; 95% CI; (-1.87, -0.12); p=0.026)) and sitagliptin+metformin treated groups (MD  -1.09; 95% CI; (-1.69, -0.49); p<0.001)). Also, the intervention has influenced body mass index in sitagliptin treated (MD  -0.23; 95% CI; (-0.45, 0.02); p=0.033)) and sitagliptin+metformin treated groups (MD -0.52; 95% CI; (-0.96, 0.08); p=0.020)) comparing to placebo.

CONCLUSION

Our results demonstrated that sitagliptin administration with or without metformin might reduce the body weight and body mass index if these drugs are taken for more than 6 months.

Determination of sitagliptin in human plasma using a smart electrochemical sensor based on electroactive molecularly imprinted nanoparticles

Sitagliptin is a hypoglycaemic agent used to reduce blood sugar levels in patients with type 2 diabetes mellitus (T2DM). Real time monitoring of sitagliptin levels is crucial to prevent overdose, which might cause liver, kidney and pancreatic diseases. As an alternative solution, a sitagliptin voltammetric sensor was fabricated using artificial receptors called electroactive molecularly imprinted polymer nanoparticles (nanoMIPs). The nanoMIP tagged with a redox probe (ferrocene) combines both the recognition and reporting functions. Traditional electrochemical sensors determine the redox activity of an analyte. Thus, they are influenced by interfering molecules and the nature of the sample. These innovative nanoMIPs allow us to easily design and customise sensors, increase their sensitivity and minimise the cross reactivity in biological samples. The present technology replaces the traditional enzyme-mediator pairs used in traditional biosensors. The polymer composition was optimized "in silico" using docking and screening methods. Nanoparticles were synthesized via free radical polymerization and a solid phase method and then characterized by infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The specific sitagliptin nanoparticles were covalently immobilized on platinum electrodes via silane and carbodiimide chemistry. The determination of sitagliptin in human plasma by a nanoMIP sensor was assessed by differential pulse voltammetry (DPV). The sensor current response was directly related to the change in nanoMIP conformation triggered by the analyte. The optimisation of the sensor response was made by adjusting (i) the silane concentration, (ii) nanoMIP concentration, and (iii) immobilization time. The sensor measurements in plasma revealed high selectivity and a sensitivity of 32.5 ± 0.6 nA pM^-1 towards sitagliptin, and the limit of detection of the fabricated sensor was found to be 0.06 pM. The sensor displayed a satisfactory performance for the determination of sitagliptin in spiked human plasma, demonstrating the potential of this technology for drug monitoring and clinical diagnosis.

Exenatide, Metformin, or Both for Prediabetes in PCOS: A Randomized, Open-label, Parallel-group Controlled Study

CONTEXT

Up to 40% of patients with polycystic ovary syndrome (PCOS) have prediabetes; an optimal pharmacotherapy regimen for diabetes prevention in PCOS is yet to be established.

OBJECTIVE

To evaluate clinical efficacy of exenatide (EX), metformin (MET), or combination (COM) for prediabetes in PCOS.

DESIGN

Randomized, open-label, parallel-group controlled trial.

SETTING

Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.

PATIENTS

PCOS with prediabetes (fasting plasma glucose 5.6-6.9 mmol/L and/or 2 hour post glucose 7.8-11.0 mmol/L on oral glucose tolerance test [OGTT]). A total of 150 out of 183 eligible enrollees completed the study.

INTERVENTION

EX (10-20μg daily), MET (1500-2000 mg daily), or COM (EX plus MET) for 12 weeks.

MAIN OUTCOME MEASURES

Sustained remission rate of prediabetes (primary endpoint, a normal OGTT after 12 weeks of treatment followed by 12 weeks of washout on no drug treatment) along with anthropometric, hormonal, metabolic, and pancreatic β-cell function parameters (secondary endpoints) and potential mechanisms were assessed.

RESULTS

Impaired glucose tolerance was found the dominant prediabetes phenotype. Overall sustained prediabetes remission rate was 50.7%. Remission rate of COM group (64%, 32/50) or EX group (56%, 28/50) was significantly higher than that of the MET group (32%, 16/50) (P = .003 and .027, respectively). EX was associated with superior suppression of 2-hour glucose increment in OGTT. A 2-step hyperglycemic clamp study revealed that EX had led to higher postprandial insulin secretion than MET, potentially explaining the higher remission rate.

CONCLUSIONS

Compared with MET monotherapy, EX or COM achieved higher rate of remission of prediabetes among PCOS patients by improving postprandial insulin secretion.

Anti-inflammatory properties of antidiabetic drugs: A "promised land" in the COVID-19 era?

Inflammation is implicated in the development and severity of the coronavirus disease 2019 (COVID-19), as well as in the pathophysiology of diabetes. Diabetes, especially when uncontrolled, is also recognized as an important risk factor for COVID-19 morbidity and mortality. Furthermore, certain inflammatory markers [i.e. C-reactive protein (CRP), interleukin-6 (IL-6) and ferritin] were reported as strong predictors of worse outcomes in COVID-19 positive patients. The same biomarkers have been associated with poor glycemic control. Therefore, achieving euglycemia in patients with diabetes is even more important in the era of the COVID-19 pandemic. Based on the above, it is clinically interesting to elucidate whether antidiabetic drugs may reduce inflammation, thus possibly minimizing the risk for COVID-19 development and severity. The present narrative review discusses the potential anti-inflammatory properties of certain antidiabetic drugs (i.e. metformin, pioglitazone, sitagliptin, linagliptin, vildagliptin, alogliptin, saxagliptin, liraglutide, dulaglutide, exenatide, lixisenatide, semaglutide, empagliflozin, dapagliflozin, canagliflozin), with a focus on CRP, IL-6 and ferritin.

Abscisic Acid Treatment in Patients with Prediabetes

Aim: to evaluate the effects of abscisic acid (ABA), contained in dwarf peaches, on the regression of impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) conditions. Materials and methods: sixty-five patients with IFG or IGT were randomized to take ABA or placebo for 3 months. We evaluated: fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycated hemoglobin (HbA_1c), fasting plasma insulin (FPI), homeostatic model assessment of insulin resistance (HOMA-IR), lipid profile and high sensitivity C-reactive protein (Hs-CRP). At baseline, and after 3 months, all patients underwent an oral glucose tolerance test (OGTT), an euglycemic hyperinsulinemic clamp, and a glucagon test. Results: a significant reduction of HbA_1c, FPG, PPG, FPI and HOMA-IR was observed in the ABA group. After 3 months, 26.7% of patients returned to a normal glycemic status in the ABA group versus zero patients in placebo group; 20.0% were classified as IFG and 53.3% as IGT in the nutraceutical group versus 33.3% and 63.3% in the placebo group. The M value was higher in the ABA group at the end of the treatment. Finally, Hs-CRP was reduced after 3 months of ABA consumption. Conclusions: abscisic acid can be effective in ameliorating glyco-metabolic compensation and in reducing inflammatory status in patients with IFG or IGT.

Efficacy of Modern Diabetes Treatments DPP-4i, SGLT-2i, and GLP-1RA in White and Asian Patients With Diabetes: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

The pathophysiology of type 2 diabetes differs markedly by ethnicity.

PURPOSE

A systematic review and meta-analysis was conducted to assess the impact of ethnicity on the glucose-lowering efficacy of the newer oral agents, sodium-glucose cotransporter 2 inhibitors (SGLT-2i), glucagon-like peptide 1 receptor agonists (GLP-1RA), and dipeptidyl peptidase 4 inhibitors (DPP-4i), using evidence from randomized clinical trials (RCTs).

DATA SOURCES

A literature search was conducted in PubMed of all randomized, placebo-controlled trials of DPP-4i, SGLT-2i, and GLP-1RA. The search strategy was developed based on Medical Subject Headings (MeSH) terms and keywords.

STUDY SELECTION

A total of 64 studies that qualified for meta-analysis after full-text review based on predefined inclusion and exclusion criteria-RCTs with at least 50 patients in each arm, >70% of population from Asian or white group, duration ≥24 weeks, and publication up to March 2019-were selected for systematic review and meta-analysis.

DATA EXTRACTION

Data extraction was done for aggregated study-level data by two independent researchers. Absolute changes in HbA_1c (%) from baseline to 24 weeks between the drug and placebo were considered as the primary end point of the study.

DATA SYNTHESIS

Change in HbA_1c was evaluated by computing mean differences and 95% CIs between treatment and placebo arms.

LIMITATIONS

The study is based on summarized data and could not be separated based on East Asians and South Asians.

CONCLUSIONS

The glucose-lowering efficacy of SGLT-2i, and to a lesser extent DPP-4i, was greater in studies of predominantly Asian ethnicity compared with studies of predominantly white ethnicity. There was no difference seen by ethnicity for GLP-1RA.

Random-effects meta-analysis of combined outcomes based on reconstructions of individual patient data

Meta-analyses of clinical trials typically focus on one outcome at a time. However, treatment decision-making depends on an overall assessment of outcomes balancing benefit in various domains and potential risks. This calls for meta-analysis methods for combined outcomes that encompass information from different domains. When individual patient data (IPD) are available from all studies, combined outcomes can be calculated for each individual and standard meta-analysis methods would apply. However, IPD are usually difficult to obtain. We propose a method to estimate the overall treatment effect for combined outcomes based on first reconstructing pseudo IPD from available summary statistics and then pooling estimates from multiple reconstructed datasets. We focus on combined outcomes constructed from two continuous original outcomes. The reconstruction step requires the specification of the joint distribution of these two original outcomes, including the correlation which is often unknown. For outcomes that are combined in a linear fashion, misspecifications of this correlation affect efficiency, but not consistency, of the resulting treatment effect estimator. For other combined outcomes, an accurate estimate of the correlation is necessary to ensure the consistency of treatment effect estimates. To this end, we propose several ways to estimate this correlation under different data availability scenarios. We evaluate the performance of the proposed methods through simulation studies and apply these to two examples: (a) a meta-analysis of dipeptidyl peptidase-4 inhibitors vs control on treating type 2 diabetes; and (b) a meta-analysis of positive airway pressure therapy vs control on lowering blood pressure among patients with obstructive sleep apnea.

Effects of treatment with metformin and/or sitagliptin on beta-cell function and insulin resistance in prediabetic women with previous gestational diabetes

AIM

To investigate the effect of sitagliptin (SITA) and metformin (MET) monotherapy as well as in combination (MET+SITA) on beta-cell function and insulin sensitivity in women with recent gestational diabetes (GDM) and impaired glucose regulation (IGR: impaired fasting glucose and/or impaired glucose tolerance).

MATERIAL AND METHODS

Forty women were randomly assigned to receive SITA (100 mg qd), MET (850 mg bid) or MET+SITA (50 + 850 mg bid) for 16 weeks. A 75 g oral glucose tolerance test (OGTT) and +125 mg/dL hyperglycaemic clamp followed by 5 g i.v. L-arginine were performed at baseline and end of study. The primary outcome of the study was the mean change in arginine-stimulated insulin secretion rate during the hyperglycaemic clamp test from baseline to 16-week therapy.

RESULTS

At week 16, body mass index declined in all groups (-1.2 ± 0.2 kg/m² ; P < 0.05). MET+SITA gave a greater increase of first phase_{(2-10 min)} insulin secretion and arginine-stimulated response (720.3 ± 299.0 to 995.5 ± 370.3 pmol/L and 3.2 ± 0.6 to 4.8 ± 1.0 pmoL/min, respectively, both P < 0.05) compared with MET and SITA. Similarly, MET+SITA was more effective in increasing OGTT-based glucose sensitivity (55.7 ± 11.3 to 108 ± 56.2 pmol x min^-1 m^-2 x mM^-1 ; P = 0.04) and insulin-stimulated glucose disposal (M/I: 2.2 ± 0.5 to 4.6 ± 1.3 mg/kg/min÷μIU/min/ml; P = 0.04; Matsuda index [SI]: 3.1 ± 0.4 to 5.7 ± 1.1; P = 0.03) compared with either MET or SITA. Disposition index (ISSI-2) increased with MET+SITA and SITA (both P < 0.05), while no significant change was observed in MET. Among MET+SITA women, 33% reverted to normal glucose tolerance (NGT) compared with 14% with MET and 7% with SITA (P < 0.05).

CONCLUSION

This study shows that MET+SITA is superior to SITA and MET monotherapy regarding beta-cell function and insulin sensitivity improvement in IGR women with previous GDM, and may offer a potential pharmacologic intervention to reduce the risk of type 2 diabetes in this high-risk population.

Efficacy and hypoglycemic risk of sitagliptin in obese/overweight patients with type 2 diabetes compared with GLP-1 receptor agonists: A meta-analysis

OBJECTIVE

The purpose of this study was to assess the efficacy and hypoglycemic risk of sitagliptin versus that of GLP-1 receptor agonists in the management of obese/overweight patients with T2DM.

METHODS

EMBASE, PubMed, Cochrane Library, and ClinicalTrials.gov were searched; randomized controlled trials comparing the efficacy of sitagliptin versus that of GLP-1 receptor agonists in obese/overweight patients with T2DM were included. The mean BMI of participants for each study was ≥30 kg/m. We conducted a meta-analysis according to the methods specified in the Cochrane Handbook for Systematic Reviews of Interventions. RevMan 5.1 software was used to perform the meta-analysis. The Cochrane Q test and I statistics were used to estimate the heterogeneity among studies. The results are expressed as the mean difference (MD) or risk ratio (RR) with 95% confidence intervals.

RESULTS

A total of 8 eligible studies were included in our meta-analysis. Compared with GLP-1 receptor agonists, sitagliptin was less effective at reducing HbA1c (0.42 [0.27, 0.56]), FPG (0.78 [0.36, 1.19]), PPG (2.61 [1.35, 3.87]), and body weight (1.42 [0.71, 2.14]). Conversely, there were no significant differences in SBP reduction (0.38 [-1.14, 1.89]), DBP reduction (-0.30 [-1.00, 0.39]), and hypoglycemic risk (1.09 [0.50, 2.35]).

CONCLUSION

For obese/overweight patients, sitagliptin may exert a less potent effect on HbA1C, FPG, PPG, and weight reduction than GLP-1 receptor agonists, but these drugs had a similar efficacy in reducing blood pressure; furthermore, there was no significant difference in hypoglycemic risk.

Effect of dipeptidyl-peptidase-4 inhibitors on C-reactive protein in patients with type 2 diabetes: a systematic review and meta-analysis

Background

Dipeptidyl peptidase-4 inhibitors (DPP-4i) are emerging glucose-lowering agents through interacting with DPP-4 substrate, impact of which on systemic inflammation in type 2 diabetes mellitus (T2DM) remains unknown. This study aimed to evaluate the effect of DPP-4i on modulating serum levels of C-reactive protein (CRP) in T2DM.

Methods

PubMed, Cochrane library and Embase databases were searched. Randomized controlled trials (RCTs) with comparators were selected. A random-effects model was used for quantitative data analysis. Heterogeneity was evaluated with I² index. Sensitivity analysis was performed using the one-study remove approach.

Results

Sixteen trials with 1607 patients with T2DM were included. Pooled analysis of DPP-4i demonstrated a significant decrease in serum CRP concentrations (− 0.86 mg/L, 95% CI, − 1.36 to − 0.36). No significant difference was found between DPP-4i and active comparators on serum CRP concentrations (0.64 mg/L, 95% CI, − 0.10 to 1.37). Pooled analysis proved to be stable and credible by sensitivity analysis. In subgroup analysis, changes in serum concentrations of CRP were significantly associated with short diabetes duration (− 0.23 mg/L, 95% CI, − 0.41 to − 0.05).

Conclusions

DDP-4i effectively reduced serum CRP levels and showed no stronger effect than traditional oral antidiabetic agents.

International Prospective Register for Systematic Review (PROSPERO) number: CRD42017076838.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1086-4) contains supplementary material, which is available to authorized users.

The efficacy and safety of dipeptidyl peptidase-4 inhibitors for type 2 diabetes: a Bayesian network meta-analysis of 58 randomized controlled trials

AIMS

The aim is to evaluate the efficacy and safety of dipeptidyl peptidase-4 inhibitors (DPP4-I: sitagliptin, saxagliptin, linagliptin, vildagliptin and alogliptin) in patients with type 2 diabetes.

METHODS

We searched the Cochrane Library, PubMed, EMBASE, Chinese Biomedical Database (CBM), China National Knowledge Infrastructure (CNKI), and the Wanfang Database from inception to April, 2018. Randomized controlled trials were included if they compared the different versions of DPP4-I with each other or with placebo in treatment of type 2 diabetes. Bayesian network meta-analysis and pairwise meta-analysis were performed to evaluate the efficacy and safety of the different kinds of DPP4-I and placebo. The data were analyzed using STATA 12.0 and WinBUGS1.4 software.

RESULTS

We identified 58 eligible studies (with 31356 patients) involving 14 treatment arms. Indirect comparison results showed that except for alogliptin, a decrease was found for all DPP4-I versus the placebo for hemoglobin A1c (HbA1c) with vildagliptin50 twice daily (BID) showing the highest probability. Linagliptin5 once daily (QD) decreased the level of fasting plasma glucose (FPG) the most for all DPP4-I versus the placebo; when comparing them with each other, alogliptin25QD was more effective when compared with sitagliptin100QD and vildaglipti50BID; linagliptin5qd had the highest decrease impact on body mass index (BMI). Except for hypoglycemia and upper respiratory tract infection (URTI), there are no statistical significance on incidence of adverse events and the body weight when DPP4-I are compared with each other or with placebo.

CONCLUSION

Our network meta-analysis presents the associations of DPP4-I versus placebos on HbA1c, FPG, 2 h postprandial blood glucose (2HPPG), BMI, body weight and adverse events. DPP4-I have a lowering effect on the glycemic level (HbA1c, FPG), especially vildaglipti50BID and linagliptin10QD, respectively. Besides, linagliptin5QD has the greatest probabilities of reducing BMI. In addition, DPP4-I were associated with not increasing the incidence of adverse events. Among them, vildagliptin100QD and sitagliptin100QD have the lowest probability in reducing the incidence of hypoglycemia and URTI, respectively.

G protein-coupled receptor 119 agonist DS-8500a effects on pancreatic β-cells in Japanese type 2 diabetes mellitus patients

AIMS/INTRODUCTION

Pancreatic β-cell dysfunction contributes to type 2 diabetes mellitus progression. Drugs that improve insulin secretion might be a valuable treatment approach. The present study aimed to evaluate the effect of the G protein-coupled receptor 119 agonist DS-8500a on insulin secretory capacity in Japanese type 2 diabetes mellitus patients.

MATERIALS AND METHODS

This single-center, 4-week, randomized, double-blind, cross-over study enrolled 21 Japanese drug-naïve type 2 diabetes mellitus patients aged ≥20 years with glycated hemoglobin ≥7.0 and <9.0% (NCT02669732, JapicCTI 163126). Patients received 75 mg of DS-8500a or a placebo orally daily for 4 weeks in a random order. A combined euglycemic-hyperinsulinemic and hyperglycemic clamp test was carried out to assess insulin secretion and insulin sensitivity before and after each 4-week treatment period. Primary end-points were first-phase insulin secretion (insulin area under the curve [AUC]180-190 min and C-peptide AUC180-190 min during the clamp test) and second-phase insulin secretion (insulin AUC190-300 min and C-peptide AUC190-300 min ). Insulin sensitivity (M and M/I values), disposition index and changes in lipid profile were also assessed.

RESULTS

DS-8500a significantly increased first- and second-phase insulin AUC (P = 0.0011, P = 0.0112) and C-peptide AUC (P = 0.0012, P < 0.0001) compared with the placebo. At day 28, M and M/I values were comparable with those of the placebo, whereas the disposition index for insulin and C-peptide was significantly increased (P = 0.0108, P = 0.0002). Total cholesterol, low-density lipoprotein cholesterol and triglyceride concentrations were significantly reduced, and high-density lipoprotein cholesterol concentrations were significantly increased compared with the placebo. No significant treatment-emergent adverse events occurred.

CONCLUSION

DS-8500a enhanced insulin secretory capacity, but not insulin sensitivity.

Effect of Linagliptin and Voglibose on metabolic profile in patients with Type 2 Diabetes: a randomized, double-blind, placebo-controlled trial

Background

Dipeptidyl peptidase 4 (DPP4) inhibitors improve glycemic control by promoting GLP1-mediated glucose-dependent insulin secretion and suppression of glucagon. Sitagliptin and vildagliptin have been shown to improve insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). However, these patients had uncontrolled blood glucose at inclusion; therefore, the improvement in insulin sensitivity observed in these studies could be attributed to the drug per se and/or reduction in glucotoxicity. This study examines the effect of linagliptin on insulin sensitivity and β-cell function in patients with well-controlled T2DM.

Methods

Thirty patients with T2DM of duration ≤5 years, and having HbA1c < 7.5% were randomized to receive linagliptin, voglibose or placebo (n = 10 each), and were followed up for 6 months. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp, and insulin secretory response was measured by basal (M₀) and postprandial (M₁) β-cell function, and area under curve (AUC) for C-peptide during mixed meal tolerance test.

Results

The median HbA1c of the study subjects at inclusion was 6.9% and there was no significant difference among the groups in terms of age, duration of diabetes, body mass index (BMI), HbA1c, insulin sensitivity, AUC of C-peptide and M₀ and M₁ at baseline. At the end of the study, there was a modest reduction in HbA1c (− 0.2%) in the linagliptin group, and a significant decrease (− 0.8%) in the voglibose group, as compared to placebo (p = 0.038). However, there were no significant differences in insulin sensitivity, M₀ and M₁ and AUC of C-peptide, within, or among the groups.

Conclusion

Linagliptin modestly improves glycemic profile in patients with well controlled T2DM; however, it may not have an effect on insulin sensitivity in these patients.

Trial registration

Retrospectively Registered in Clinicaltrials.gov (ID number, NCT02097342). Registered: March 27, 2014.

Review of methods for measuring β-cell function: Design considerations from the Restoring Insulin Secretion (RISE) Consortium

The Restoring Insulin Secretion (RISE) study was initiated to evaluate interventions to slow or reverse the progression of β-cell failure in type 2 diabetes (T2D). To design the RISE study, we undertook an evaluation of methods for measurement of β-cell function and changes in β-cell function in response to interventions. In the present paper, we review approaches for measurement of β-cell function, focusing on methodologic and feasibility considerations. Methodologic considerations included: (1) the utility of each technique for evaluating key aspects of β-cell function (first- and second-phase insulin secretion, maximum insulin secretion, glucose sensitivity, incretin effects) and (2) tactics for incorporating a measurement of insulin sensitivity in order to adjust insulin secretion measures for insulin sensitivity appropriately. Of particular concern were the capacity to measure β-cell function accurately in those with poor function, as is seen in established T2D, and the capacity of each method for demonstrating treatment-induced changes in β-cell function. Feasibility considerations included: staff burden, including time and required methodological expertise; participant burden, including time and number of study visits; and ease of standardizing methods across a multicentre consortium. After this evaluation, we selected a 2-day measurement procedure, combining a 3-hour 75-g oral glucose tolerance test and a 2-stage hyperglycaemic clamp procedure, augmented with arginine.

Comparative Study on Adding Pioglitazone or Sitagliptin to Patients with Type 2 Diabetes Mellitus Insufficiently Controlled With Metformin

BACKGROUND

Diabetes mellitus is a progressive disorder that often requires combination therapy.

AIM

This study aimed to compare and study of add-on sitagliptin versus pioglitazone in patients with type 2 diabetes inadequately controlled with metformin.

METHODS

This 12-week, randomised, open-label and single centre study compared sitagliptin (100 mg daily, n = 80) and pioglitazone (30 mg daily, n = 80) in type 2 diabetic patients whose disease was not adequately controlled with metformin.

RESULTS

The mean change in HbA1c from baseline was -1.001 ± 0.83 with sitagliptin and -0.75 ± 1.20 with pioglitazone, and there were no significant difference between groups (P = 0.132). The mean change in fasting blood sugar (FBS) was -18.48 ± 33.32 mg/dl with sitagliptin and -20.53 ± 53.97 mg/dl with pioglitazone, and there were no significant difference between groups (P = 0.773). Sitagliptin caused 1.08 ± 2.39 kg decrease in weight, whereas pioglitazone caused 0.27 ± 2.42 kg increase in weight, with a between-group difference of 0.81 kg (P < 0.001). On the other hand, in sitagliptin group, there was greater improvement in lipid profile than pioglitazone group.

CONCLUSION

Sitagliptin and Pioglitazone demonstrated similar improvements in glycemic control in type 2 diabetes mellitus patients whose diabetes had been inadequately controlled with metformin. Nevertheless, sitagliptin was more effective than pioglitazone regarding lipid and body weight change.

Linagliptin versus sitagliptin in patients with type 2 diabetes mellitus: a network meta-analysis of randomized clinical trials

Background

Diabetes is one of the most common chronic and costly diseases worldwide and type 2 diabetes is the most common type which accounts for about 90% of cases with diabetes. New medication-therapy regimens such as those containing linagliptin alone or in combination with other medications (within the category of DDP-4 inhibitors) must be evaluated in terms of efficacy and compared with other currently used drugs and then enter the medication list of the country. Hence, this study aimed to compare the clinical efficacy of the two drugs, i.e. linagliptin and sitagliptin, in patients with type 2 diabetes.

Methods

A systematic review was conducted to identify all clinical trials published by 2015 which compared the two drugs in patients with type 2 diabetes. Using keywords such as “linagliptin”, “type 2 diabetes mellitus”, “sitagliptin” and related combinations, we searched databases including Scopus, PubMed, and Web of Science. The quality of the selected studies was evaluated using the Jadad score. Considering primary and secondary outcomes extracted from the reviewed studies, a network meta-analysis was used to conduct a systematic comparison between the two studied drugs.

Results

This network meta-analysis included 32 studies (Linagliptin vs PLB: n = 8, Sitagliptin vs PLB: n = 13, Linagliptin + MET vs PLB + MET: n = 4, and Sitagliptin + MET vs PLB + MET: n = 7) and a total of 13,747 patients. The results showed no significant difference between linagliptin and sitagliptin in terms of key efficacy and safety outcomes such as HbA1c changes from baseline, body weight change from baseline, percentage of patients achieving HbA1c <7, and percentage of patients experiencing hypoglycemic events (p > 0.05). The results showed that the efficacy of the two drug regimens was the same.

Conclusions

Based on the results, there was no significant difference between the two drugs, i.e. linagliptin and sitagliptin, in terms of efficacy; in other words, the efficacy of the two drugs was the same. Therefore, the use of these two drugs depends on their availability and cost.

Graphical abstract

Graphical abstract of the network meta-analysis performed to evaluate the alternatives under the study.

Electronic supplementary material

The online version of this article (10.1186/s40199-017-0189-6) contains supplementary material, which is available to authorized users.

Evaluating the costs of glycemic response with canagliflozin versus dapagliflozin and empagliflozin as add-on to metformin in patients with type 2 diabetes mellitus in the United Arab Emirates

OBJECTIVE

This study evaluates the cost of achieving glycemic control with three sodium glucose co-transporter 2 (SGLT2) inhibitors, canagliflozin, dapagliflozin, and empagliflozin, in patients with type 2 diabetes mellitus (T2DM) from the payer perspective in the United Arab Emirates (UAE).

METHODS

A systematic literature review identified randomized controlled trials of antihyperglycemic agents as add-on to metformin in patients with T2DM of 26 ± 4 weeks in duration, published by 10 September 2014. A Bayesian network-meta analysis (NMA) compared HbA1c changes with canagliflozin 100 and 300 mg versus dapagliflozin 10 mg and empagliflozin 10 and 25 mg. The cost associated with a 1% placebo-adjusted HbA1c reduction with each SGLT2 inhibitor as add-on to metformin was calculated based on NMA results and UAE drug costs.

RESULTS

In the NMA, canagliflozin 100 and 300 mg were associated with HbA1c reductions (-0.67% and -0.79%) compared with dapagliflozin 10 mg (-0.41%) and empagliflozin 10 and 25 mg (-0.57% and -0.64%). Probabilities of canagliflozin 100 mg performing better were 79%, 60%, and 53% versus dapagliflozin 10 mg and empagliflozin 10 and 25 mg, respectively; probabilities for canagliflozin 300 mg performing better were 88%, 72%, and 65%, respectively. The cost per 1%-point reduction in HbA1c was projected to be lower with canagliflozin 100 and 300 mg ($448 and $422) compared with dapagliflozin 10 mg ($785) and empagliflozin 10 and 25 mg ($527 and $563).

CONCLUSIONS

Canagliflozin may provide a greater glycemic response at a lower effective cost than dapagliflozin or empagliflozin for patients with T2DM inadequately controlled with metformin from the payer perspective in the UAE.

Dipeptidyl peptidase-4 inhibitors and the risk of heart failure: a systematic review and meta-analysis

BACKGROUND

Given recent discrepant results from randomized controlled trials (RCTs), we examined the totality of RCT evidence assessing the association between dipeptidyl peptidase-4 (DPP-4) inhibitors and heart failure.

METHODS

MEDLINE, Embase and ClinicalTrials.gov were searched without language restrictions to August 2016 for RCTs comparing DPP-4 inhibitors to placebo or no therapy for a period of 24 weeks or more. We included all heart failure outcomes when listed either as a serious adverse event or adverse event. Pooled analyses used random-effects.

RESULTS

We identified 100 RCTs (n = 79 867) - 3 large cardiovascular-safety RCTs (SAVOR-TIMI 53[saxagliptin]/n = 16 492, EXAMINE[alogliptin]/n = 5380, and TECOS[sitagliptin]/n = 14 735), and 97 smaller RCTs with a primary outcome that was usually change in glycated hemoglobin. Virtually all RCTs were high-quality, multicentre, placebo-controlled trials. A total of 96% (1192/1244) of heart failure events were prespecified, blindly adjudicated and required hospital admission. Pooled results suggested a 13% increase in heart failure (relative risk [RR] 1.13, 95% confidence interval [CI] 1.01-1.26, I2 = 0%; 32 RCTs, n = 54 640, 1244 events). When including only the 3 large RCTs, the increase was similar, but not significant (RR 1.14, 95% CI 0.97-1.32; 3 RCTs, n = 36 543, 1169 adjudicated events; number needed to harm 246) owing to heterogeneity (I2 = 42%), which lead to wider CIs, because SAVOR-TIMI 53 showed increased heart failure (RR 1.26, 95% CI 1.06-1.49) and TECOS showed no effect (RR 1.00, 95% CI 0.83-1.19).

INTERPRETATION

Despite pooled data from 79 867 patients, whether DPP-4 inhibitors increase heart failure overall or exhibit within-class differences remains unresolved. Our results highlight the importance of ongoing trials that are comparing DPP-4 inhibitors to placebo, although no large cardiovascular-safety RCTs are comparing different DPP-4 inhibitors to each other; consequently, these will address the overall but not class-difference question.

Impact of dipeptidyl peptidase-4 inhibitors on serum adiponectin: a meta-analysis

BACKGROUND

Adiponectin, an adipose-specific protein, is negatively correlated with pro-atherogenic low-density lipoprotein cholesterol (LDL-C) and other cardiovascular risk factors such as insulin resistance. Therefore, low levels of adiponectin are associated with a higher risk for diabetes and cardiovascular disease. Dipeptidyl peptidase-4 inhibitors (DPP4i) have been used for the treatment of type 2 diabetes mellitus (T2DM) as reversible inhibitors through interacting with DPP4 substrate and increase serum incretins such as glucagon-like peptide-1 (GLP-1). The present study aimed to evaluate the effect of DPP4i on serum adiponectin in T2DM patients.

METHODS

The PubMed, Embase, and Cochrane library databases were searched from inception to February 2016. Randomized controlled trials, evaluating the DPP4i (sitagliptin and vildagliptin) versus comparator (placebo or active-comparison), in T2DM patients with duration of ≥ 12 weeks, were identified. Weighted differences in means of adiponectin levels were calculated by using a fixed or random-effects model.

RESULTS

Ten randomized controlled trials, including 1,495 subjects, were identified. Compared with placebo, DPP4i (sitagliptin and vildagliptin) treatment significantly elevated adiponectin levels by 0.74 μg/mL (95% confidence interval [CI], 0.45 to 1.03) relative to that using an active-comparison by 0.00 μg/mL (95% CI, -0.57 to 0.56). Compared with active-comparison, vildagliptin treatment increased adiponectin levels by 0.32 μg/mL (95% CI, -0.01 to 0.65), whereas sitagliptin treatment decreased adiponectin levels by -0.24 μg/mL (95% CI, -1.07 to 0.58). Trials examining effects of other DPP4i were not found.

CONCLUSIONS

Sitagliptin and vildagliptin increased serum adiponectin levels and had no stronger effect than traditional oral antidiabetic drugs. Further trials with larger sample size are needed to confirm the results and investigate the association between serum adiponectin levels and treatment of other DPP-4 inhibitors.

TRIAL REGISTRATION

Registration No in PROSPERO: CRD42016037399 .

Effect of trelagliptin on vascular endothelial functions and serum adiponectin level in patients with type 2 diabetes: a preliminary single-arm prospective pilot study

Background

Trelagliptin, an oral DPP-4 inhibitor, which is administered once per week and characterized by a long half-life in blood. The effects of trelagliptin on vascular endothelial functions have not been clarified to date. The objective of the present study was to examine the effects of trelagliptin on vascular endothelial functions in patients with type 2 diabetes mellitus (DM) using flow-mediated dilatation (FMD), adiponectin, and asymmetric dimethylarginine (ADMA) as evaluation indicators.

Methods

This study was a preliminary single-arm prospective pilot study. The subjects of this study were type 2 DM patients aged 20–74 years, who visited our outpatient department. The patients were treated with trelagliptin, and their FMD, adiponectin, and ADMA levels were measured at baseline and at 12 weeks after initial treatment to determine the changes during the study period.

Results

A total of 27 patients, excluding three dropouts, were included in the population for analysis. Trelagliptin treatment showed no significant changes in FMD (2.42 ± 2.7% at baseline vs. 2.66 ± 3.8% post-treatment, P = 0.785) and ADMA (0.41 ± 0.0 µg/mL at baseline vs. 0.40 ± 0.0 µg/mL post-treatment, P = 0.402). Trelagliptin treatment resulted in a significant increase of serum adiponectin level (7.72 ± 6.9 µg/mL at baseline vs. 8.82 ± 8.3 µg/mL post-treatment, P < 0.002).

Conclusions

In this pilot study, trelagliptin treatment showed no significant changes in FMD. On the other hand, it was believed that trelagliptin treatment may increase serum adiponectin level.

Trial Registrationhttp://www.umin.ac.jp (Trial ID UMIN000018311)

Standardized Mixed-Meal Tolerance and Arginine Stimulation Tests Provide Reproducible and Complementary Measures of β-Cell Function: Results From the Foundation for the National Institutes of Health Biomarkers Consortium Investigative Series

OBJECTIVE

Standardized, reproducible, and feasible quantification of β-cell function (BCF) is necessary for the evaluation of interventions to improve insulin secretion and important for comparison across studies. We therefore characterized the responses to, and reproducibility of, standardized methods of in vivo BCF across different glucose tolerance states.

RESEARCH DESIGN AND METHODS

Participants classified as having normal glucose tolerance (NGT; n = 23), prediabetes (PDM; n = 17), and type 2 diabetes mellitus (T2DM; n = 22) underwent two standardized mixed-meal tolerance tests (MMTT) and two standardized arginine stimulation tests (AST) in a test-retest paradigm and one frequently sampled intravenous glucose tolerance test (FSIGT).

RESULTS

From the MMTT, insulin secretion in T2DM was >86% lower compared with NGT or PDM (P < 0.001). Insulin sensitivity (Si) decreased from NGT to PDM (∼50%) to T2DM (93% lower [P < 0.001]). In the AST, insulin secretory response to arginine at basal glucose and during hyperglycemia was lower in T2DM compared with NGT and PDM (>58%; all P < 0.001). FSIGT showed decreases in both insulin secretion and Si across populations (P < 0.001), although Si did not differ significantly between PDM and T2DM populations. Reproducibility was generally good for the MMTT, with intraclass correlation coefficients (ICCs) ranging from ∼0.3 to ∼0.8 depending on population and variable. Reproducibility for the AST was very good, with ICC values >0.8 across all variables and populations.

CONCLUSIONS

Standardized MMTT and AST provide reproducible and complementary measures of BCF with characteristics favorable for longitudinal interventional trials use.

Efficacy, safety and impact on β-cell function of dipeptidyl peptidase-4 inhibitors plus metformin combination therapy in patients with type 2 diabetes and the difference between Asians and Caucasians: a meta-analysis

BACKGROUND

To assess the efficacy, safety and impact on β-cell function of DPP-4 inhibitors plus metformin in T2DM patients and their difference between Asians and Caucasians.

METHODS

We conducted a literature search (from 1 January 2000 to 14 April 2015) for RCTs of DPP-4 inhibitors plus metformin combination therapy in T2DM.

RESULTS

A total of 27 RCTs were included. Compared with metformin, DPP-4 inhibitor plus metformin therapy was associated with higher reduction in HbA1c [-0.61 %, -0.69 to -0.52], FPG [-1.10 mmol/l, -1.29 to -0.92], TC [-0.11 mmol/l, -0.20 to -0.02], TG [-0.21 mmol/l, -0.33 to -0.10], HOMA-IR [-0.19, -0.36 to -0.02], gastrointestinal adverse events [OR 0.86, 0.77-0.97] and higher increment in HOMA-β [10.21, 7.73-12.69]. Comparison of HbA1c, FPG, body weight and HOMA-IR changes between Asian and Caucasian patients did not show a significant between-group difference of -0.05 % (-0.30, 0.20; P = 0.69), 0.17 mmol/l (-0.52, 0.85; P = 0.62), -0.15 kg (-0.64, 0.35; P = 0.53) and 0.27 (-0.98, 1.53; P = 0.64) compared with metformin. Comparisons of HOMA-β between Asian and Caucasian patients showed a significant between-group difference of -7.68 (-14.95, -0.42; P = 0.04).

CONCLUSION

DPP-4 inhibitors and metformin therapy was effective and safe for T2DM patients. The glucose-lowering efficacy of DPP-4 inhibitors was same in Asian and Caucasian patients, although the effect on HOMA-β was inferior in Asian patients. The effect of DPP-4 inhibitors on HOMA-IR and body weight in Asian patients was comparable with that observed in Caucasian patients.

Improved glucose regulation in type 2 diabetic patients with DPP-4 inhibitors: focus on alpha and beta cell function and lipid metabolism

Inhibition of dipeptidyl peptidase-4 (DPP-4) is an established glucose-lowering strategy for the management of type 2 diabetes mellitus. DPP-4 inhibitors reduce both fasting and postprandial plasma glucose levels, resulting in reduced HbA1c with low risk for hypoglycaemia and weight gain. They act primarily by preventing inactivation of the incretin hormones glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1, thereby prolonging the enhanced endogenous levels of these hormones after meal ingestion. This in turn causes islet and extrapancreatic effects, including increased glucose sensing in islet alpha and beta cells. These effects result in increased insulin secretion and decreased glucagon secretion being more effective in hyperglycaemic states and reduced insulin secretion and increased glucagon secretion being more effective during hypoglycaemia. Other secondary pharmacological actions of DPP-4 inhibitors include mobilisation and burning of fat during meals, decrease in fat extraction from the gut, reduction of fasting lipolysis and liver fat and increase in LDL particle size. These actions contribute to the clinical effects of DPP-4 inhibition, and the reduced demand for insulin could also lead to a durability benefit. This review summarises the current knowledge of the secondary pharmacological actions of DPP-4 inhibitors that lead to improved glucose regulation in patients with type 2 diabetes, focusing on alpha and beta cell function and lipid metabolism.

Sitagliptin/Metformin Versus Insulin Glargine Combined With Metformin in Obese Subjects With Newly Diagnosed Type 2 Diabetes

To compare the therapeutic effects of different regimens in Chinese obese type 2 diabetic mellitus (T2DM) patients. From October 2013 to July 2014, a total of 166 T2DM outpatients who attended the Shanghai Changhai Hospital and the Yijishan Hospital of Wannan Medical College were randomly assigned into an experimental sitagliptin/metformin combined with low caloric diet group (n = 115) and an insulin glargine combined with metformin control group (n = 51). Inclusion criteria were body mass index (BMI) ≥ 25 kg/m and diagnosed with T2DM with glycosylated hemoglobin (glycated hemoglobin A1C [HbA1c]) >9%. Main outcome parameters were fasting plasma glucose, postprandial plasma glucose, BMI, HbA1c, fasting C-peptide, 2-h postprandial C-peptide, triglyceride (TG), total cholesterol (TC), high-density cholesterol (HDL-C), and low-density cholesterol (LDL-C), which were determined by the 75 g steamed-bun meal tolerance test before and 4, 8, 12, and 24 weeks after the treatment started. Treatment costs and life quality were also assessed. BMI, HbA1C, TG, TC, and LDL were significantly more reduced (P < 0.000) and HbA1c significantly better improved in the experimental group than in the control group (<6.5% in 24 [20.87%] vs 2 [3.92%], P < 0.001; <7% in 65 [56.52%] vs 12 [23.53%], P < 0.001). Quality of life scores in the experimental group increased more than in the control group (P < 0.001). The costs for the experimental group medication were less than for other regimens. For obese T2DM patients diagnosed with a glycosylated hemoglobin level >9%, oral sitagliptin/metformin combined with a low caloric diet effectively and economically maintained glycemic control and significantly improved life quality.

Dipeptidyl peptidase-4 inhibition and narrow-band ultraviolet-B light in psoriasis (DINUP): study protocol for a randomised controlled trial

BACKGROUND

Moderate to severe psoriasis is a systemic inflammatory disease associated with insulin resistance, obesity and type 2 diabetes (T2DM). Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that improves glycaemia and has a marketing authorisation for the treatment of T2DM. Non-immunosuppressive therapies that are effective for psoriasis and its associated comorbidities would be a significant advance in the treatment of this chronic disease.

METHODS/DESIGN

This is a single centre, 39-week, prospective, randomised, open label, clinical trial of oral sitagliptin (Januvia(®)) in psoriasis patients who are due to undergo a course of narrow-band ultraviolet-B (NB-UVB) phototherapy. We plan to enrol 120 participants and allocate participants on a random and 1:1 basis to receive sitagliptin 100 mg daily for 24 weeks combined with NB-UVB or NB-UVB monotherapy. Participants will be followed up for 12 weeks after sitagliptin therapy is discontinued. The primary endpoint is the change in Psoriasis Area and Severity Index (PASI) 24 weeks after treatment initiation. Secondary endpoints include cumulative NB-UVB dose, number of NB-UVB treatments required to clear psoriasis, proportions of participants who achieve PASI-50 (50 % reduction in PASI from baseline), PASI-75, PASI-90 and the proportion of participants who relapse in each group. We will also analyse changes in cardiovascular disease risk factors, serum cytokine and hormone levels and peripheral blood mononuclear expression of immune proteins at 24 and 36 weeks. A subgroup of participants will have skin biopsies taken and analysed for skin levels and expression of immune cells, receptors, hormones and immune proteins. The genetic or epigenetic profile that predicts best response to DPP-4 inhibitor therapy will be analysed. The safety endpoints include the rate and severity of adverse events.

DISCUSSION

This is the first randomised clinical trial assessing dipeptidyl peptidase-4 inhibition therapy in psoriasis. We hypothesise that sitagliptin therapy in combination with NB-UVB improves psoriasis severity compared to NB-UVB monotherapy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02347501 (Date of registration: 27 January 2015).

The role of dipeptidyl peptidase 4 inhibitors in fat metabolism in patients with type 2 diabetes and obesity

Objective. To evaluate the influence of combined therapy of sitagliptin and metformin on fat metabolism in patients with type 2 diabetes mellitus.Methods. The study included 82 patients (age, 55.3±9.1 years) with obesity and lipid metabolism disorders. None of the patients had reached their target glycated haemoglobin levels after metformin and diet therapy. Patients in group 1 (n=42) received 1.5–2-g metformin daily before the study and were switched to a formulation of 100-mg sitagliptin and 2-g metformin once a day. Patients in group 2 (n=40) were on a diet therapy before inclusion and were started on 2-g metformin/day. The following were evaluated at baseline and after 6 months of therapy: fasting glucose levels, postprandial glucose levels, glycated haemoglobin, weight, body mass index, waist circumference and lipid profile; insulin, proinsulin, leptin and adiponectin levels; insulin resistance using the homeostatic model assessment (HOMA) of β-cell function (HOMA-β) and insulin resistance (HOMA-IR). In addition, magnetic resonance imaging was performed to assess the amount of visceral fat for the total cohort.Results. After 6 months, glycated haemoglobin decreased by 18.52% (p 0.001) in group 1 and by 8.17% (p 0.001) in group 2. Fasting plasma glucose and postprandial glucose levels in group 1 were reduced by 21% (p 0.001) and 26.35% (p 0.001), respectively; the corresponding reductions in group 2 were 1.45% (p 0.05) and 5.31% (p 0.05), respectively. HOMA-β increased by 33% in group 1 (p 0.001) and by 11% in group 2 (p 0.05). Adiponectin levels increased by 27.06% (p 0.001) in group 1 and by 7.16% in group 2 (p 0.001). Leptin levels were reduced by 30.47% (p 0.001) in group 1 and by 5.41% in group 2 (p 0.001). Magnetic resonance imaging showed a 7.52% reduction in visceral fat for group 1 (p 0.001) and a 1.76% reduction for group 2 (p 0.01). The comparison of subcutaneous fat dynamics did not show statistically significant differences between the groups.Conclusion. Compared with metformin monotherapy, sitagliptin and metformin combination therapy had a prominent effect on non-glycaemic parameters, with more marked decreases in visceral fat and leptin and increases in adiponectin levels.

Four-Year Durability of Initial Combination Therapy with Sitagliptin and Metformin in Patients with Type 2 Diabetes in Clinical Practice; COSMIC Study

OBJECTIVES

We investigated the efficacy of initial combination therapy with sitagliptin and metformin in patients with type 2 diabetes for 4 years in clinical practice.

METHODS

Between 2009 and 2010, we reviewed 1,178 patients with type 2 diabetes (HbA1c ≥7.5% or 58 mmol/mol) prescribed initial combination therapy with sitagliptin and metformin. After excluding 288 patients without a second follow-up, 890 individuals (age, 58.0 ± 12.5 years; BMI, 25.4 ± 3.5 kg/m2; HbA1c, 8.6 ± 1.1%) were followed up with every 3-6 months for 4 years. Homeostasis model assessments for insulin resistance and β-cell function (HOMA-β) were recorded at baseline. The response criterion was HbA1c reduction by ≥0.8% from baseline or attainment of the target HbA1c (≤7.0% or 53 mmol/mol). At the end of every year of treatment, changes in HbA1c from the baseline were assessed.

RESULTS

After 1 year, 72.2% of patients with initial combination therapy had responded, defined as HbA1c reduction ≥0.8% or attainment of the target HbA1c ≤7.0%. After 4 years, 35.4% of the patients still showed a response, with an HbA1c level of 7.0 ± 0.9%. A high HbA1c level at baseline was the most significant independent predictor of the long-term response (P<0.001). In addition, low HOMA-β was a significant predictor of a greater reduction in HbA1c. This treatment was generally well tolerated over the 4-year follow-up period, without any serious adverse events.

CONCLUSIONS

This real-world follow-up study shows a persistent glucose-reducing effect of initial combination therapy with sitagliptin and metformin for up to 4 years.

Implications of incretin-based therapies on cardiovascular disease

BACKGROUND

Incretin-based therapies offer another treatment option for patients with type 2 diabetes. Agents that provide glycaemic control in addition to attenuating cardiovascular disease (CVD) risk factors are important for diabetes management. This review will focus on the off-target effects of incretin-based therapies on CVD risk factors [body weight, blood pressure (BP), lipid profile and albuminuria], major adverse cardiovascular events (MACE), heart failure (HF) and beta-cell preservation.

METHODS

A literature search was conducted to identify English-language publications for incretin-based therapies evaluating the following off-target end-points: body weight, BP, lipid profile, albuminuria, MACE, HF and beta-cell function. Randomised controlled trials (RCTs) were prioritised as the primary source of information.

RESULTS

Overall, incretin-based therapies have shown beneficial effects on CVD risk factors, and glucagon-like peptide 1 (GLP-1) receptor agonists appear to have a more pronounced effect compared with dipeptidyl peptidase-4 inhibitors. RCTs are being conducted to determine if these positive effects on CVD risk factors translate to a reduction in MACE. To date, these studies have not shown an increase in MACE. A signal of increased hospitalisations for HF was observed with saxagliptin, warranting continued evaluation and vigilance in high-risk patients. In addition, incretin-based therapies have shown positive effects on measures of beta-cell function supporting their durability in the management of diabetes.

CONCLUSIONS

Incretin-based therapies are an important treatment option for patients with type 2 diabetes, offering beneficial effects on CVD risk factors without increasing MACE.

Comparative efficacy and safety of antidiabetic drug regimens added to metformin monotherapy in patients with type 2 diabetes: a network meta-analysis

Introduction

When first line therapy with metformin is insufficient for patients with type 2 diabetes (T2D), the optimal adjunctive therapy is unclear. We assessed the efficacy and safety of adjunctive antidiabetic agents in patients with inadequately controlled T2D on metformin alone.

Materials and Methods

A search of MEDLINE and CENTRAL, clinicaltrials.gov, regulatory websites was performed. We included randomized controlled trials of 3–12 months duration, evaluating Food and Drug Administration or European Union approved agents (noninsulin and long acting, once daily basal insulins) in patients experiencing inadequate glycemic control with metformin monotherapy (≥1500 mg daily or maximally tolerated dose for ≥4 weeks). Random-effects network meta-analyses were used to compare the weighted mean difference for changes from baseline in HbA1c, body weight (BW) and systolic blood pressure (SBP), and the risk of developing hypoglycemia, urinary (UTI) and genital tract infection (GTI).

Results

Sixty-two trials evaluating 25 agents were included. All agents significantly reduced HbA1c vs. placebo; albeit not to the same extent (range, 0.43% for miglitol to 1.29% for glibenclamide). Glargine, sulfonylureas (SUs) and nateglinide were associated with increased hypoglycemia risk vs. placebo (range, 4.00–11.67). Sodium glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 analogs, miglitol and empagliflozin/linagliptin significantly reduced BW (range, 1.15–2.26kg) whereas SUs, thiazolindinediones, glargine and alogliptin/pioglitazone caused weight gain (range, 1.19–2.44kg). SGLT2 inhibitors, empagliflozin/linagliptin, liraglutide and sitagliptin decreased SBP (range, 1.88–5.43mmHg). No therapy increased UTI risk vs. placebo; however, SGLT2 inhibitors were associated with an increased risk of GTI (range, 2.16–8.03).

Conclusions

Adding different AHAs to metformin was associated with varying effects on HbA1c, BW, SBP, hypoglycemia, UTI and GTI which should impact clinician choice when selecting adjunctive therapy.

Incretin response in Asian type 2 diabetes: Are Indians different?

Incretin-based therapy has clearly emerged as one of the most sought out strategy in managing type 2 diabetes, primarily because they generally do not causes hypoglycemia and possess weight-neutral or weight losing properties. Efficacy-wise too, these agents, are more or less similar to commonly used drugs metformin and sulfonylureas. Interestingly, some studies recently suggested that glycemic response to these incretin-based therapies could also differ ethnicity-wise. Subsequently, meta-analysis from these studies also suggested that Asians may have better response to these incretin-based therapies. This review will be an attempt to critically analyze those studies available in literature and to address as to why East-Asians and South-Asians may have different incretin response compared to non-Asians.

Effects of miglitol, sitagliptin, and initial combination therapy with both on plasma incretin responses to a mixed meal and visceral fat in over-weight Japanese patients with type 2 diabetes. "the MASTER randomized, controlled trial"

AIM

To assess changes in circulating incretin levels and body fat compositions with initial combination therapy with α-glucosidase inhibitor and dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes (T2D).

METHODS

In this multicenter open-label 24-week trial, Japanese over-weight (BMI ≥ 25 kg/m(2)) patients with T2D not taking medication or taking metformin and/or sulfonylurea were randomly assigned to receive either 50mg of miglitol three times a day (M, n=14), 50mg of sitagliptin once a day (S, n=14), or a combination of both (M+S, n=13). Changes in plasma incretin levels during a meal tolerance test (MTT) and body fat composition with impedance method were evaluated.

RESULTS

During MTT, postprandial plasma glucose levels decreased more after M+S than after M or S, and postprandial serum insulin levels decreased significantly after M and M+S whereas they increased after S. After M, active gastric inhibitory polypeptide (aGIP) decreased significantly at 30 min despite a significant increase at 120 min. After S, aGIP levels increased significantly throughout the MTT. After M+S, aGIP increased significantly at 0 and 120 min despite of significant decrease at 30 min. M+S further enhanced postprandial active glucagon-like peptide-1 levels during MTT than S did. Total body fat mass decreased significantly after M and M+S. Visceral fat mass decreased significantly only after M+S. Serum adiponectin increased significantly only after M+S.

CONCLUSIONS

In over-weight patients with T2D, M+S may have a beneficial effect on adiposity with relation to these different effects on two incretins.

Comparative effectiveness of dipeptidylpeptidase-4 inhibitors in type 2 diabetes: a systematic review and mixed treatment comparison

OBJECTIVE

To compare the safety and efficacy of the dipeptidylpeptidase-4 (DPP-4) inhibitors in patients with type 2 diabetes and inadequate glycemic control.

DESIGN

Systematic review of randomized controlled trials (RCTs), health economic evaluation studies, systematic reviews, and meta-analyses, followed by primary Bayesian mixed treatment comparison meta-analyses (MTCs), and secondary frequentist direct-comparison meta-analyses using a random-effects model. Outcomes were reported as weighted mean change from baseline, or odds ratio (OR) with 95% credible interval.

DATA SOURCES

MEDLINE, MEDLINE In-Process, EMBASE, and BIOSIS via Dialog ProQuest; Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews via EBSCO; four diabetes and two technical congress abstracts; and health technology assessment organization websites.

ELIGIBILITY CRITERIA

Patients with type 2 diabetes and inadequate glycemic control receiving any pharmacological anti-diabetic treatment.

DATA EXTRACTION AND ANALYSIS

Title/abstracts were reviewed for eligibility, followed by full-text review of publications remaining after first pass. A three-person team filtered articles and an independent reviewer checked a random selection (10%) of filtered articles. Data extraction and quality assessment of studies were also independently reviewed. Five DPP-4 inhibitors (alogliptin, linagliptin, saxagliptin, sitagliptin, and vildagliptin) were compared via meta-analysis (where data were available) as monotherapy, dual therapy (plus metformin, sulfonylurea, pioglitazone, or insulin), and triple therapy (plus metformin/sulfonylurea).

RESULTS

The review identified 6,601 articles; 163 met inclusion criteria and 85 publications from 83 RCTs contained sufficient or appropriate data for analysis. MTCs demonstrated no differences between DPP-4 inhibitors in mean change from baseline in glycosylated hemoglobin (HbA1c) or body weight, or the proportions of patients achieving HbA1c <7% or experiencing a hypoglycemic event, apart from in patients on alogliptin plus metformin, who achieved HbA1c <7% more frequently than those treated with saxagliptin plus metformin [OR 6.41 (95% CI 3.15-11.98) versus 2.17 (95% CI 1.56-2.95)].

CONCLUSIONS

This systematic review and MTC showed similar efficacy and safety for DPP-4 inhibitors as treatment for type 2 diabetes, either as monotherapy or combination therapy.

A pilot three-month sitagliptin treatment increases serum adiponectin level in Japanese patients with type 2 diabetes mellitus--a randomized controlled trial START-J study

Background

The dipeptidyl-peptidase-IV (DPP-4) inhibitors, including sitagliptin, are used for the treatment of type 2 diabetes mellitus (T2DM). Adiponectin, an adipocyte-derived circulating protein, has anti-atherosclerotic and anti-diabetic properties and is effectively elevated in bloodstream by thiazolidinediones, an insulin sensitizer. However, the effect of sitagliptin treatment on serum adiponectin level in T2DM has not fully elucidated in Japanese T2DM patients. The aim of the present study was to examine the effect of sitagliptin treatment on serum adiponectin levels in T2DM subjects.

Methods

Twenty-six consecutive Japanese T2DM outpatients were recruited between April 2011 and March 2013, and randomized into the control (conventional treatment, n = 10) group and sitagliptin treatment group (n = 16). Serum adiponectin was measured by enzyme-linked immunosorbent assay.

Results

Indices of glycemic control, such as hemoglobin A1c, glycated albumin, and 1.5-anhydro-D-glucitol, were significantly improved after the three-month treatment in both the control and sitagliptin groups. Serum adiponectin level was significantly increased in sitagliptin group from 6.7 ± 0.8 to 7.4 ± 1.0 μg/mL without change of body mass index (p = 0.034), while serum adiponectin level was not altered in the control group (p = 0.601).

Conclusion

In Japanese T2DM patients, serum adiponectin level was elevated by three-month treatment with sitagliptin without change of body weight.

Trial registration

UMIN000004721

Assessment of pancreatic β-cell function: review of methods and clinical applications

Type 2 diabetes mellitus (T2DM) is characterized by a progressive failure of pancreatic β-cell function (BCF) with insulin resistance. Once insulin over-secretion can no longer compensate for the degree of insulin resistance, hyperglycemia becomes clinically significant and deterioration of residual β-cell reserve accelerates. This pathophysiology has important therapeutic implications. Ideally, therapy should address the underlying pathology and should be started early along the spectrum of decreasing glucose tolerance in order to prevent or slow β-cell failure and reverse insulin resistance. The development of an optimal treatment strategy for each patient requires accurate diagnostic tools for evaluating the underlying state of glucose tolerance. This review focuses on the most widely used methods for measuring BCF within the context of insulin resistance and includes examples of their use in prediabetes and T2DM, with an emphasis on the most recent therapeutic options (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists). Methods of BCF measurement include the homeostasis model assessment (HOMA); oral glucose tolerance tests, intravenous glucose tolerance tests (IVGTT), and meal tolerance tests; and the hyperglycemic clamp procedure. To provide a meaningful evaluation of BCF, it is necessary to interpret all observations within the context of insulin resistance. Therefore, this review also discusses methods utilized to quantitate insulin-dependent glucose metabolism, such as the IVGTT and the euglycemic-hyperinsulinemic clamp procedures. In addition, an example is presented of a mathematical modeling approach that can use data from BCF measurements to develop a better understanding of BCF behavior and the overall status of glucose tolerance.

Effect of sitagliptin on glycemic control and beta cell function in Japanese patients given basal-supported oral therapy for type 2 diabetes

We evaluated the effect of sitagliptin on glycemic control, endogenous insulin secretion, and beta cell function in Japanese patients with type 2 diabetes mellitus (T2DM) receiving a combination of oral antidiabetics and basal insulin analog glargine (basal-supported oral therapy [BOT]). Twenty-one patients showing inadequate glycemic control with BOT were given dipeptidylpeptidase-4 inhibitor (DPP-4I) sitagliptin at 50 mg/day for 12 weeks. Clinical markers of glycemic control, HbA1c, glycated albumin (GA), and 1,5-anhydroglucitol (1,5-AG), were measured before and 4 and 12 weeks after the start of sitagliptin. A 2-hour morning meal test was performed upon enrollment and at 12 weeks, and plasma glucose (PG), serum C-peptide, and plasma intact proinsulin (PI) were measured. HbA1c, GA, and 1,5-AG at 4 and 12 weeks were significantly improved over enrollment levels. The area under the PG concentration curve (AUC-PG) during the meal test at 12 weeks was significantly reduced (from 350 ± 17 mg ･ hr/dL before sitagliptin treatment to 338 ± 21 mg ･ hr/dL [mean ± SE], P < 0.05,); the AUC-C-peptide was unchanged (from 3.4 ± 0.4 ng ･ hr/mL to 3.6 ± 0.5 ng ･ hr/mL). However, both fasting and 2-hour PI/C-peptide ratios at 12 weeks were significantly decreased (from 13.3 ± 2.3 to 11.1 ± 2.0 [P < 0 .05] and from 9.5 ± 1.6 to 5.3 ± 0.9 [P < 0.01], respectively). Adding sitagliptin to BOT in Japanese T2DM patients appears to improve glycemic control without increasing endogenous insulin secretion and to reduce fasting and 2-hour postprandial PI/C-peptide ratios.

Comparative effects of sitagliptin and metformin in patients with type 2 diabetes mellitus: a meta-analysis

BACKGROUND

Sitagliptin has been widely used in the treatment of type 2 diabetes mellitus (T2DM); however, the therapeutic efficacy of sitagliptin remains inconclusive in randomized controlled studies on T2DM in which metformin has served as a control.

OBJECTIVES

The present meta-analysis aimed to compare the therapeutic efficacy of sitagliptin and metformin in the treatment of T2DM.

METHODS

We searched the following databases (Medline, Embase, Cochrane databases, Chinese Medical Journal Database, and the Chinese National Knowledge Infrastructure from inception until April 2013), and identified randomized controlled trials (RCTs) involving sitagliptin and metformin for T2DM. Two independent authors determined whether or not these trials met the inclusion criteria. Then, the variance of results from each study was calculated, and I(2) was employed for evaluation of heterogeneity.

RESULTS

One hundred and twenty-one studies were identified, of which seven were included for further analysis. For T2DM, the therapeutic efficacy of sitagliptin and metformin was comparable in reducing HbA1c (P = 0.148, standard mean difference [SMD] = 0.13, 95% confidence interval [CI] = -0.05, 0.30), decreasing BMI (P = 0.063, SMD = 0.26, 95% CI = -0.01, 0.54), and improving the homeostasis model assessment (HOMA)-β (P = 0.285, SMD = -0.05, 95% CI = -0.15, 0.04), but sitagliptin was inferior to metformin in improving HOMA-IR (P = 0.003, SMD = 0.16, 95% CI = 0.06, 0.27).

CONCLUSIONS

Sitagliptin is similar to metformin in reducing HbA1c, decreasing body weight, and improving the function of beta cells, but is inferior to metformin in improving insulin sensitivity. More RCTs with large sample sizes are required to provide evidence for the rational application of sitagliptin.

Effects of exenatide and metformin in combination on some adipocytokine levels: a comparison with metformin monotherapy

The aim of this study was to evaluate the effects of exenatide on levels of serum adipocytokines and on β-cell function. The study was conducted between 2008 and 2012. After a run-in period with metformin, 174 patients with type-2 diabetes were randomly distributed to either a group receiving exenatide at 10 μg twice daily, or a group receiving the placebo, for 12 months. We evaluated body mass index (BMI), blood pressure, glycemic control, lipid profile, fasting plasma insulin (FPI), HOMA-IR, HOMA-β, fasting plasma proinsulin (FPPr), proinsulin : fasting plasma insulin ratio (Pr/FPI ratio), C-peptide, glucagon, retinol binding protein-4 (RBP-4), visfatin, omentin-1, and microalbuminuria. We used ELISA methods to assess the various parameters. Patients also underwent a combined euglycemic-hyperinsulinemic and hyperglycemic clamp, with subsequent arginine stimulation. After 12 months, a combination of exenatide and metformin produced a better decrease in body mass, BMI, glycemic control, FPI, FPPr, FPPr/FPI ratio, HOMA-IR, and glucagon level. Treatment with exenatide + metformin was superior to the placebo + metformin in increasing HOMA-β, C-peptide, and β-cell function. Significant negative correlations were found between M value, an index of insulin sensitivity, and measured adipocytokines. In conclusion, the combination of exenatide + metformin plays a role in improving some adipocytokine levels, and is better than metformin alone. The significant negative correlation between M value and measured adipocytokines is another confirmation of the positive effects linked to the improvement in insulin sensitivity.

A comparison between sitagliptin or glibenclamide in addition to metformin + pioglitazone on glycaemic control and β-cell function: the triple oral therapy

AIMS

To evaluate which triple oral therapy between metformin + pioglitazone + sitagliptin and metformin + pioglitazone + glibenclamide can be more useful in improving glycaemic control and should be preferred in clinical practice.

METHODS

During the 2-year run-in period, patients were instructed to take metformin monotherapy for the first year, then a combination of metformin and pioglitazone for the second year, then patients were randomized to add glibenclamide or sitagliptin to the dual combination of metformin and pioglitazone for another year.

RESULTS

Body weight reached with sitagliptin at 36 months was lower than that reached with glibenclamide. Fasting plasma insulin and homeostasis model assessment of insulin resistance were significantly increased by triple therapy with glibenclamide and decreased by that with sitagliptin. While sitagliptin did not change homeostasis model assessment of β-cell function, this value was significantly increased by glibenclamide. Fasting plasma proinsulin was not influenced by triple oral therapy including glibenclamide, while it was decreased by the therapy including sitagliptin compared to glibenclamide. Triple oral therapy with sitagliptin better improved β-cell function measures compared with the glibenclamide therapy.

CONCLUSIONS

Sitagliptin should be preferred to glibenclamide as an addition to the metformin + pioglitazone combination for its better protection of β-cell secretion and its neutral effect on body weight.

A randomized, double-blind, comparative therapy evaluating sitagliptin versus glibenclamide in type 2 diabetes patients already treated with pioglitazone and metformin: a 3-year study

OBJECTIVES

This study evaluated if triple oral therapy can be useful in improving glycemic control compared with metformin monotherapy and with a metformin and pioglitazone combination. Furthermore, we also compared a triple metformin+pioglitazone+glibenclamide combination with a metformin+pioglitazone+sitagliptin one.

SUBJECTS AND METHODS

After a 2-year run-in therapy-augmenting phase with metformin and pioglitazone, 453 overweight, type 2 diabetes patients were randomized to 1 year of sitagliptin versus 1 year of glibenclamide to evaluate, as the primary outcome, the variation of β-cell function both in a fasting state and after an euglycemic hyperinsulinemic and hyperglycemic clamp. As secondary outcomes we evaluated glycemic control and insulin resistance.

RESULTS

Both the triple therapy combinations were more effective in reducing glycated hemoglobin compared with metformin monotherapy and with dual therapy metformin+pioglitazone. Fasting plasma insulin level and the homeostasis model assessment insulin resistance index were significantly increased by triple therapy with glibenclamide and decreased by the one with sitagliptin. Although sitagliptin did not change the homeostasis model assessment β-function index, this value was significantly increased by glibenclamide. The fasting plasma proinsulin level was decreased by sitagliptin. Triple therapy with sitagliptin greatly improved β-cell function measures compared with the glibenclamide one and also compared with metformin monotherapy and with the metformin+pioglitazone combination.

CONCLUSIONS

Dual combination therapy is more effective than monotherapy in improving glycemic control. When double therapy is not enough to reach an adequate glycemic control, sitagliptin should be preferred to glibenclamide as the third agent because of its positive effect on β-cells.

Variations in inflammatory biomarkers following the addition of sitagliptin in patients with type 2 diabetes not controlled with metformin

OBJECTIVE

The effects of dipeptidyl peptidase-4 (DPP-4) inhibition on adipose tissue inflammation remain obscure. The aim of this study was to evaluate the effects of the addition of sitagliptin on the β-cell function and various inflammatory biomarkers in type 2 diabetic patients.

METHODS

After a run-in period of taking metformin, 178 diabetic patients with poor glycemic control were randomized to take sitagliptin at a dose of 100 mg once a day or a placebo in addition to metformin for 12 months. We evaluated the following parameters at three, six, nine and twelve months: body mass index (BMI), glycemic control, the homeostasis model assessment insulin resistance index (HOMA-IR), the homeostasis model assessment β-cell function index (HOMA-β), the proinsulin/fasting plasma insulin ratio (Pr/FPI ratio) and the levels of fasting plasma insulin (FPI), fasting plasma proinsulin (FPPr), C-peptide, glucagon, resistin, vaspin, omentin-1 and tumor necrosis factor-α (TNF-α). Before and twelve months after the addition of sitagliptin, the patients underwent combined euglycemic hyperinsulinemic and hyperglycemic clamping with subsequent arginine stimulation to assess insulin sensitivity and secretion.

RESULTS

Treatment with sitagliptin + metformin was more effective than placebo + metformin in improving glycemic control, the HOMA-IR and the glucagon level and increasing the HOMA-β and all β-cell measurements after combined euglycemic hyperinsulinemic and hyperglycemic clamping with subsequent arginine stimulation. Regarding inflammatory biomarkers, sitagliptin + metformin more effectively reduced the levels of resistin, vaspin and omentin-1 than placebo + metformin.

CONCLUSION

When treatment with metformin alone is not adequate for obtaining glycemic control, the addition of sitagliptin can be considered due to its actions in preserving the β-cell function and reducing the levels of biomarkers of inflammation.

Unraveling oxyntomodulin, GLP1's enigmatic brother

Oxyntomodulin (OXM) is a peptide secreted from the L cells of the gut following nutrient ingestion. OXM is a dual agonist of the glucagon-like peptide-1 receptor (GLP1R) and the glucagon receptor (GCGR) combining the effects of GLP1 and glucagon to act as a potentially more effective treatment for obesity than GLP1R agonists. Injections of OXM in humans cause a significant reduction in weight and appetite, as well as an increase in energy expenditure. Activation of GCGR is classically associated with an elevation in glucose levels, which would be deleterious in patients with T2DM, but the antidiabetic properties of GLP1R agonism would be expected to counteract this effect. Indeed, OXM administration improved glucose tolerance in diet-induced obese mice. Thus, dual agonists of the GCGR and GLP1R represent a new therapeutic approach for diabetes and obesity with the potential for enhanced weight loss and improvement in glycemic control beyond those of GLP1R agonists.