Vildagliptin compared to glimepiride on post-prandial lipemia and on insulin resistance in type 2 diabetic patients

Efficacy and Safety of DPP-4 Inhibitors and Metformin Combinations in Type 2 Diabetes: A Systematic Literature Review and Network Meta-Analysis

Objective

Several oral antidiabetic regimens are available for treating type 2 diabetes mellitus (T2DM), dipeptidyl peptidase-4 inhibitors (DPP4i) being one of them. We conducted a network meta-analysis (NMA) comparing DPP4i plus metformin (Met) combination with other Met-based oral antidiabetic drug (OAD) combinations used in treating patients with T2DM.

Methods

We searched PubMed and Embase from inception until 19th April, 2022 for phase II and phase III trials in patients with T2DM on Met-based traditional OADs. The primary outcome was assessed by change in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and 2-hour post-prandial blood glucose (2h-PPG). The secondary safety outcomes assessed were hypoglycemic events, serious adverse events (SAEs), cardiovascular (CV) events, and gastrointestinal (GI) events.

Results

Sixty-two trials were included in the analysis. The combination of DPP4i + Met revealed a comparable mean reduction in HbA1c levels to the glinides (Gli) + Met combination (mean difference [MD]: -0.03%, 95% CI: 0.69, -0.65), although the difference was not statistically significant. The mean HbA1c reduction with DPP4i + Met was greater than with sulfonylureas (SU) + Met (MD: -0.05, 95% CI: -0.29, 0.39), thiazolidinedione (TZD) + Met (MD: -0.69, 95% CI: -1.39, -0.02), and SU + TZD (MD: 0.21; 95% CI: -1.30, 1.71), with no statistical significance. DPP4i + Met demonstrated a non-significant lower incidence of CV events in comparison to TZD + Met (RR: 1.01, 95% CI: 0.46, 2.45) and SU + Met (RR: 1.06, 95% CI: 0.61, 2.06).

Conclusion

DPP4i in combination with Met was efficacious and had a well-tolerated safety profile compared with other traditional OADs. This combination can be considered as a suitable treatment option for patients with T2DM.

Postprandial Hyperlipidemia: Its Pathophysiology, Diagnosis, Atherogenesis, and Treatments

Postprandial hyperlipidemia showing postprandial increases in serum triglyceride (TG) is associated with the development of atherosclerotic cardiovascular disease (ASCVD). To diagnose postprandial hyperlipidemia, the oral fat loading test (OFLT) should be performed; however, this test is very time-consuming and is difficult to perform. Elevated serum TG levels reflect an increase in TG-rich lipoproteins (TRLs), such as chylomicrons (CM), very low-density lipoproteins (VLDL), and their remnants (CM remnants [CMRs] and VLDL remnants [VLDLRs]). Understanding of elevation in CMR and/or VLDLR can lead us to understand the existence of postprandial hyperlipidemia. The measurement of apo B48, which is a constituent of CM and CMR; non-fasting TG, which includes TG content in all lipoproteins including CM and CMR; non-high-density lipoprotein cholesterol (non-HDL-C), which includes TRLs and low-density lipoprotein; and remnant cholesterol are useful to reveal the existence of postprandial hyperlipidemia. Postprandial hyperlipidemia is observed in patients with familial type III hyperlipoproteinemia, familial combined hyperlipidemia, chronic kidney disease, metabolic syndrome and type 2 diabetes. Postprandial hyperlipidemia is closely related to postprandial hyperglycemia, and insulin resistance may be an inducing and enhancing factor for both postprandial hyperlipidemia and postprandial hyperglycemia. Remnant lipoproteins and metabolic disorders associated with postprandial hyperlipidemia have various atherogenic properties such as induction of inflammation and endothelial dysfunction. A healthy diet, calorie restriction, weight loss, and exercise positively impact postprandial hyperlipidemia. Anti-hyperlipidemic drugs such pemafibrate, fenofibrate, bezafibrate, ezetimibe, and eicosapentaenoic acid have been shown to improve postprandial hyperlipidemia. Anti-diabetic drugs including metformin, alpha-glucosidase inhibitors, pioglitazone, dipeptidyl-peptidase-4 inhibitors and glucagon-like peptide 1 analogues have been shown to ameliorate postprandial hyperlipidemia. Although sodium glucose cotransporter-2 inhibitors have not been proven to reduce postprandial hyperlipidemia, they reduced fasting apo B48 and remnant lipoprotein cholesterol. In conclusion, it is important to appropriately understand the existence of postprandial hyperlipidemia and to connect it to optimal treatments. However, there are some problems with the diagnosis for postprandial hyperlipidemia. Postprandial hyperlipidemia cannot be specifically defined by measures such as TG levels 2 h after a meal. To study interventions for postprandial hyperlipidemia with the outcome of preventing the onset of ASCVD, it is necessary to define postprandial hyperlipidemia using reference values such as IGT.

Dipeptidyl-Peptidase-IV Inhibitors, Imigliptin and Alogliptin, Improve Beta-Cell Function in Type 2 Diabetes

OBJECTS

Imigliptin is a novel dipeptidyl peptidase-4 inhibitor. In the present study, we aimed to evaluate the effects of imigliptin and alogliptin on insulin resistance and beta-cell function in Chinese patients with type-2 diabetes mellitus (T2DM).

METHODS

A total of 37 Chinese T2DM patients were randomized to receive 25 mg imigliptin, 50 mg imigliptin, placebo, and 25 mg alogliptin (positive drug) for 13 days. Oral glucose tolerance tests were conducted at baseline and on day 13, followed by the oral minimal model (OMM).

RESULTS

Imigliptin or alogliptin treatment, compared with their baseline or placebo, was associated with higher beta-cell function parameters (φ_s and φ_tot) and lower glucose area under the curve (AUC) and postprandial glucose levels. The changes in the AUC for the glucose appearance rate between 0 and 120 min also showed a decrease in imigliptin or alogliptin groups. However, the insulin resistance parameter, fasting glucose, was not changed. For the homeostatic model assessment (HOMA-β and HOMA-IR) parameters or secretory units of islets in transplantation index (SUIT), no statistically significant changes were found both within treatments and between treatments.

CONCLUSIONS

After 13 days of treatment, imigliptin and alogliptin could decrease glycemic levels by improving beta-cell function. By comparing OMM with HOMA or SUIT results, glucose stimulation might be more sensitive for detecting changes in beta-cell function.

Effects of newer antidiabetic drugs on nonalcoholic fatty liver and steatohepatitis: Think out of the box!

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western societies and a major cause of hepatic disease worldwide. Its more severe type, namely nonalcoholic steatohepatitis (NASH), may result in the development of cirrhosis and hepatocellular carcinoma. NAFLD, and especially NASH, are also associated with increased cardiovascular morbidity and mortality. Type 2 diabetes mellitus (T2DM) predisposes to NAFLD development and progression via insulin resistance and hyperglycemia. It has also been reported that the majority of T2DM patients have NAFLD/NASH, thus potentially further increasing their cardiometabolic risk. Current guidelines recommend to screen for NAFLD in all T2DM patients and vice-versa. Lifestyle remains the first-line therapeutic option for NAFLD/NASH. Among antidiabetic drugs, pioglitazone was shown to improve histological features of NASH. More recently, there is an increasing interest regarding the effects of newer anti-diabetic drugs, such as dipeptidyl peptidase 4 inhibitors (DPP-4i), sodium glucose cotransporter 2 inhibitors (SGLT2i), and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on NAFLD/NASH. The present narrative review considers the up-to-date data on the impact of DPP-4i, SGLT2i, and GLP-1 RAs on biochemical and/or histological markers of NAFLD/NASH. The potential clinical implications of these findings in daily practice are also discussed. Taking into consideration the global increasing prevalence of NAFLD/NASH, therapeutic options that can prevent or treat this disease will exert considerable benefits on human health.

A safety and tolerability profile comparison between dipeptidyl peptidase-4 inhibitors and sulfonylureas in diabetic patients: A systematic review and meta-analysis

BACKGROUND

The first treatment approach for type 2 diabetes mellitus is lifestyle change and metformin, but it is usually not sufficient. For some time, the anti-hyperglycemic classes of sulfonylureas and dipeptidyl peptidase-4 (DPP-4) inhibitors were considered second-line of treatment, since they show similar efficacy effect. However, the recent ADA-EASD consensus gives the preference to DPP-4 inhibitors compared to sulfonylureas, except if cost is a major problem. We performed a meta-analysis for safety and tolerability profile to comprehend which treatment has less adverse events.

METHODS

PUBMED and EMBASE databases were searched from inception until July 2017 to retrieve RCT studies comparing DPP-4 inhibitors and sulfonylureas treatments in adult type 2 diabetes patients. There was no language restriction. We extracted and combined data from studies comparison that reported safety profile and weight change. A random effect, meta-analytic model was applied to all calculations. Cochrane collaboration tool was used to assess quality and bias of the included studies. Trial registered with PROSPERO (CRD42017075823).

FINDINGS

Out of 1472 articles identified in our search and screened for eligibility, 36 studies comparing DPP-4 inhibitors and sulfonylureas were identified. DPP-4 inhibitors in combination with metformin had less overall adverse events (RR: 0·90; 95% CI, 0·86-0·94; p < 0·0001; I² = 83%; 17 studies), cardiovascular events (RR: 0·54; 95% CI, 0·37-0·79; p = 0·002; I² = 0%; 6 studies), hypoglycemia (RR: 0·17; 95% CI, 0·13-0·22; p < 0·00001; I² = 76%; 17 studies) and severe hypoglycemic events (RR: 0·10; 95% CI, 0·05-0·19; p < 0·00001; I² = 0%; 12 studies). The mean difference of the weight change was 1·92 kg in favor of DPP-4 inhibitors in combination with metformin in relation to sulfonylureas in combination with metformin. Monotherapy with DPP-4 inhibitors also had less rates of hypoglycemia (RR: 0·31; 95% CI, 0·24-0·41; p < 0·00001; I² = 0%; 8 studies) and severe hypoglycemic events (RR: 0·26; 95% CI, 0·10-0·66; p = 0·004; I² = 0%; 8 studies) and patients did not gain 1·19 kg.

INTERPRETATION

These results suggest better safety profile for DPP-4 inhibitors than sulfonylureas for both comparisons, and it is more notable when the treatment regimen includes metformin.

FUNDING

This study was funded by Takeda Pharmaceuticals, Brazil.

Efficacy of different antidiabetic drugs based on metformin in the treatment of type 2 diabetes mellitus: A network meta-analysis involving eight eligible randomized-controlled trials

Diabetes mellitus is one of the most prevalent metabolic diseases globally and it is increasing in prevalence. It is one of the most expensive diseases with respect to total health care costs per patient as a result of its chronic nature and its severe complications. To provide a more effective treatment of type 2 diabetes mellitus (T2DM), this study aims to compare different efficacies of six kinds of hypoglycemic drugs based on metformin, including glimepiride, pioglitazone, exenatide, glibenclamide, rosiglitazone, and vildagliptin, in T2DM by a network meta-analysis that were verified by randomized-controlled trials (RCTs). Eight eligible RCT in consistency with the aforementioned six hypoglycemic drugs for T2DM were included. The results of network meta-analysis demonstrated that the exenatide + metformin and vildagliptin + metformin regimens presented with better efficacy. Patients with T2DM with unsatisfactory blood glucose control based on diet control, proper exercise, and metformin treatment were included. The original regimen and dose of medication were unchanged, followed by the addition of glimepiride, pioglitazone, exenatide, glibenclamide, rosiglitazone, and vildagliptin. The results of RCTs showed that all these six kinds of drugs reduced the HbA1c level. Compared with other regimens, exenatide + metformin reduced fasting plasma glucose (FPG), fasting plasma insulin (FPI), total cholesterol (TC), and homeostasis model assessment insulin resistance index (HOMA-IR) levels, but increased the high-density lipoprotein (HDL) level; vildagliptin + metformin decreased FPI and low-density lipoprotein (LDL) levels; glibenclamide + metformin decreased the FPG level, but promoted HDL; and glimepiride + metformin decreased the TC level and rosiglitazone + metformin reduced the LDL level. Our findings indicated that exenatide + metformin and vildagliptin + metformin have better efficacy in T2DM since they can improve insulin sensitivity.

The Role of Glucagon in the Pathophysiology and Treatment of Type 2 Diabetes

Type 2 diabetes is a disease involving both inadequate insulin levels and increased glucagon levels. While glucagon and insulin work together to achieve optimal plasma glucose concentrations in healthy individuals, the usual regulatory balance between these 2 critical pancreatic hormones is awry in patients with diabetes. Although clinical discussion often focuses on the role of insulin, glucagon is equally important in understanding type 2 diabetes. Furthermore, an awareness of the role of glucagon is essential to appreciate differences in the mechanisms of action of various classes of glucose-lowering therapies. Newer drug classes such as dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists improve glycemic control, in part, by affecting glucagon levels. This review provides an overview of the effect of glucose-lowering therapies on glucagon on the basis of an extensive PubMed literature search to identify clinical studies of glucose-lowering therapies in type 2 diabetes that included assessment of glucagon. Clinical practice currently benefits from available therapies that impact the glucagon regulatory pathway. As clinicians look to the future, improved treatment strategies are likely to emerge that will either use currently available therapies whose mechanisms of action complement each other or take advantage of new therapies based on an improved understanding of glucagon pathophysiology.

Network meta-analysis of lorcaserin and oral hypoglycaemics for patients with type 2 diabetes mellitus and obesity

In addition to weight loss, randomized controlled trials have shown improvement in glycaemic control in patients taking lorcaserin. The aim of this study aim was to compare adding lorcaserin or other glucose lowering medications to metformin on weight and glycaemic control. A systematic review and network meta-analysis of randomized controlled trials were conducted. Included studies (published 1990-2014) were of lorcaserin or glucose lowering medications in type 2 diabetic patients compared to placebo or different active treatments. Studies had to report ≥1 key outcome (change in weight or HbA1c, % HbA1c <7, hypoglycaemia). Direct meta-analysis was performed using DerSimonian and Laird random effects models, and network meta-analysis with Bayesian Markov-chain Monte Carlo random effects models; 6552 articles were screened and 41 included. Lorcaserin reduced weight significantly more than thiazolidinediones, glinides, sulphonylureas and dipeptidyl peptidase-4 inhibitors, some of which may have led to weight gain. There were no significant differences in weight change between lorcaserin and alpha-glucoside inhibitors, glucagon-like peptide-1 agonists and sodium/glucose cotransporter 2 inhibitors. Network meta-analysis showed lorcaserin was non-inferior to all other agents on HbA1c reduction and % achieving HbA1c of <7%. The risk of hypoglycaemia was not significantly different among studied agents except that sulphonylureas were associated with higher risk of hypoglycaemia than lorcaserin. Although additional studies are needed, this analysis suggests in a population of patients with a body mas index of ≥27 who do not achieve glycaemic control on a single agent, lorcaserin may be added as an alternative to an add-on glucose lowering medication.

Postprandial VLDL-TG metabolism in type 2 diabetes

BACKGROUND

Type 2 diabetes is associated with excess postprandial lipemia due to accumulation of chylomicrons and VLDL particles. This is a risk factor for development of cardiovascular disease. However, whether the excess lipemia is associated with an impaired suppression of VLDL-TG secretion and/or reduced clearance into adipose tissue is unknown.

OBJECTIVE

We measured the postprandial VLDL-TG secretion, clearance and adipose tissue storage to test the hypothesis that impaired postprandial suppression of VLDL-TG secretion, combined with impaired VLDL-TG storage in adipose tissue, is associated with excess postprandial lipemia.

DESIGN

We studied 11 men with type 2 diabetes and 10 weight-matched non-diabetic men using ex-vivo labeled VLDL-TG tracers during an oral high-fat mixed-meal tolerance test to measure postprandial VLDL-TG secretion, clearance and storage. In addition, adipose tissue biopsies were analyzed for LPL activity and cellular storage factors.

RESULTS

Men with type 2 diabetes had greater postprandial VLDL-TG concentration compared to non-diabetic men. However, postprandial VLDL-TG secretion rate was similar in the two groups with equal suppression of VLDL-TG secretion rate (≈50%) and clearance rate. In addition, postprandial VLDL-TG storage was similar in the two groups in both upper body and lower body subcutaneous adipose tissue.

CONCLUSIONS

Despite greater postprandial VLDL-TG concentration, men with type 2 diabetes have similar postprandial suppression of VLDL-TG secretion and a similar ability to store VLDL-TG in adipose tissue compared to non-diabetic men. This may indicate that abnormalities in postprandial VLDL-TG metabolism are a consequence of obesity/insulin resistance more than a result of type 2 diabetes per se.

A systematic literature review on the efficacy-effectiveness gap: comparison of randomized controlled trials and observational studies of glucose-lowering drugs

Aim

To identify a potential efficacy–effectiveness gap and possible explanations (drivers of effectiveness) for differences between results of randomized controlled trials (RCTs) and observational studies investigating glucose-lowering drugs.

Methods

A systematic literature review was conducted in English language articles published between 1 January, 2000 and 31 January, 2015 describing either RCTs or observational studies comparing glucagon-like peptide-1 analogs (GLP-1) with insulin or comparing dipeptidyl peptidase-4 inhibitors (DPP-4i) with sulfonylurea, all with change in glycated hemoglobin (HbA1c) as outcome. Medline, Embase, Current Content, and Biosis were searched. Information on effect estimates, baseline characteristics of the study population, publication year, study duration, and number of patients, and for observational studies, characteristics related to confounding adjustment and selection- and information bias were extracted.

Results

From 312 hits, 11 RCTs and 7 observational studies comparing GLP-1 with insulin, and from 474 hits, 16 RCTs and 4 observational studies comparing DPP-4i with sulfonylurea were finally included. No differences were observed in baseline characteristics of the study populations (age, sex, body mass index, time since diagnosis of type 2 diabetes mellitus, and HbA1c) or effect sizes across study designs. Mean effect sizes ranged from −0.43 to 0.91 and from −0.80 to 1.13 in RCTs and observational studies, respectively, comparing GLP-1 with insulin, and from −0.13 to 2.70 and −0.20 to 0.30 in RCTs and observational studies, respectively, comparing DPP-4i and sulfonylurea. Generally, the identified observational studies held potential flaws with regard to confounding adjustment and selection- and information bias.

Conclusions

Neither potential drivers of effectiveness nor an efficacy–effectiveness gap were identified. However, the limited number of studies and potential problems with confounding adjustment, selection- and information bias in the observational studies, may have hidden a true efficacy-effectiveness gap.

Vildagliptin reduces plasma stromal cell-derived factor-1α in patients with type 2 diabetes compared with glimepiride

AIMS/INTRODUCTION

Dipeptidyl peptidase-4 inhibitors might have pleiotropic protective effects on cardiovascular disease (CVD), in contrast to sulfonylureas. Therefore, we compared various CVD risk factors between vildagliptin and glimepiride.

MATERIALS AND METHODS

We carried out a randomized, prospective and crossover trial. A total of 16 patients with type 2 diabetes whose glycated hemoglobin was >7% were randomized to add vildagliptin or glimepiride. After 12-week treatment, each drug was replaced with the other for another 12 weeks. Before and after each treatment, glucose homeostasis and CVD risk factors were assessed, and the continuous glucose monitoring system was applied to calculate glycemic variability.

RESULTS

The mean age of the participants was 60 years, 31% were men, body mass index 25.5 kg/m² and HbA1c 8.41%. Both vildagliptin and glimepiride significantly decreased glycated hemoglobin and glycemic variability indices. Despite the improved glucose homeostasis, favorable change of CVD markers was not prominent in both the arms, along with significant weight gain. Only plasma stromal cell-derived factor (SDF)-1α decreased by 30% in the vildagliptin arm. According to regression analyses, the reduction of SDF-1α was independently associated with vildagliptin usage and serum interleukin-6 changes, but white blood cells were not related with the SDF-1α changes.

CONCLUSION

Compared with glimepiride, vildagliptin arrestingly decreased plasma SDF-1α, and its clinical implications should be further investigated.

Non-alcoholic fatty liver disease and diabetes

Non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2DM) are common conditions that regularly co-exist and can act synergistically to drive adverse outcomes. The presence of both NAFLD and T2DM increases the likelihood of the development of complications of diabetes (including both macro- and micro- vascular complications) as well as augmenting the risk of more severe NAFLD, including cirrhosis, hepatocellular carcinoma and death. The mainstay of NAFLD management is currently to reduce modifiable metabolic risk. Achieving good glycaemic control and optimising weight loss are pivotal to restricting disease progression. Once cirrhosis has developed, it is necessary to screen for complications and minimise the risk of hepatic decompensation. Therapeutic disease modifying options for patients with NAFLD are currently limited. When diabetes and NAFLD co-exist, there are published data that can help inform the clinician as to the most appropriate oral hypoglycaemic agent or injectable therapy that may improve NAFLD, however most of these data are drawn from observations in retrospective series and there is a paucity of well-designed randomised double blind placebo controlled studies with gold-standard end-points. Furthermore, given the heterogeneity of inclusion criteria and primary outcomes, as well as duration of follow-up, it is difficult to draw robust conclusions that are applicable across the entire spectrum of NAFLD and diabetes. In this review, we have summarised and critically evaluated the available data, with the aim of helping to inform the reader as to the most pertinent issues when managing patients with co-existent NAFLD and T2DM.

Retraction

The following article, published online on 19 June 2014 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the Editor in Chief of Diabetic Medicine, Richard Holt and John Wiley and Sons Ltd. The retraction has been agreed due to notification of dual publication. References Derosa G, Bonaventura A, Bianchi L, Romano D, Fogari E, D'Angelo A, Maffioli P. Comparison of vildagliptin and glimepiride: effects on glycaemic control, fat tolerance and inflammatory markers in people with type 2 diabetes. Diabet Med 2014; 31: 1515-1523. Derosa G, Bonaventura A, Bianchi L, Romano D, Fogari E, D'Angelo A, Maffioli P. Comparison of vildagliptin and glimepiride: effects on glycaemic control, fat tolerance and inflammatory markers in people with type 2 diabetes. Metabolism 2014; 63: 957-967.

Effects of dipeptidyl peptidase-4 inhibitor in insulin-resistant rats with myocardial infarction

Adverse cardiac remodeling after myocardial infarction (MI) leads to progressive heart failure. Obese-insulin resistance increases risks of MI and heart failure. Although dipeptidyl peptidase-4 (DPP4) inhibitor is known to exert cardioprotection, its effects on adverse remodeling after MI in obese-insulin-resistant rats are unclear. We hypothesized that DPP4 inhibitor reduces adverse left ventricular (LV) remodeling and LV dysfunction in obese-insulin-resistant rats with MI. Rats were fed either normal diet (ND) or high-fat diet (HFD) for 12 weeks to induce obese-insulin resistance, followed by left anterior descending coronary artery ligation to induce MI. Then, rats in each dietary group were divided into five subgroups to receive vehicle, enalapril (10mg/kg/day), metformin (30mg/kg/day), DPP4 inhibitor vildagliptin (3mg/kg/day), or combined metformin and vildagliptin for 8 weeks. Heart rate variability (HRV), LV function, pathological and biochemical studies for LV remodeling, and cardiomyocyte apoptosis were determined. Obese-insulin-resistant rats had severe insulin resistance and LV dysfunction. HFD rats had a higher mortality rate than ND rats, and all treatments reduced the mortality rate in obese-insulin-resistant rats. Although all drugs improved insulin resistance, HRV, LV function as well as reduced cardiac hypertrophy and fibrosis, vildagliptin effectively reduced cardiomyocyte cross-sectional areas more than enalapril and was related to markedly decreased ERK1/2 phosphorylation. In ND rats with MI, metformin neither improved LV ejection fraction nor reduced cardiac fibrosis. The infarct size and transforming growth factor-β expression were not different among groups. In obese-insulin-resistant rats with chronic MI, DPP4 inhibitor vildagliptin exerts better cardioprotection than enalapril in attenuating adverse LV remodeling.

Systematic review and meta-analysis of vildagliptin for treatment of type 2 diabetes

This systematic review and meta-analysis provides an update on the efficacy and safety of vildagliptin for treatment of type 2 diabetes mellitus (T2DM). We searched MEDLINE, COCHRANE, EMBASE and the drug manufacturer's website for randomised controlled trials of vildagliptin in patients with T2DM. Sixty-nine studies (28,006 patients) were included in the meta-analysis. Compared with placebo vildagliptin reduced HbA1c (weighted mean difference WMD -0.69 %; 95 % CI -0.83 to -0.56 %; I (2) = 82 %), and it was as effective as other antidiabetic agents (WMD -0.01 %; 95 % CI -0.16 to 0.14 %; I (2) = 93 %), without increasing the risk for hypoglycemia (OR 0.83; 95 % CI 0.59 to 1.16; I (2) = 0 % vs. placebo, and OR 0.19; 95 % CI 0.15 to 0.24; I (2) = 78 % versus active comparators). However, it was associated with an increase in the incidence of arthralgia compared with other comparators (OR 1.23; 95 % CI 1.02 to 1.48; I (2) = 0 %). On the contrary, vildagliptin did not increase the incidence of pancreatitis (OR 0.97; 95 % CI 0.37 to 2.53; I (2) = 0 %), serious adverse events (OR 0.98; 95 % CI 0.88 to 1.09; I (2) = 0 %) or death (OR 1.10, 95 % CI 0.75 to 1.61; I (2) = 0 %). Finally, odds ratio (OR) for heart failure, and overall cardiovascular and cerebrovascular events was 0.77 (95 % CI 0.46 to 1.30; I (2) = 0 %) and 0.91 (95 % CI 0.73 to 1.14; I (2) = 0 %), respectively. Vildagliptin is an effective and safe therapeutic option for patients with T2DM, both as monotherapy and as add-on treatment.

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.

Antidiabetic Effect of Galantamine: Novel Effect for a Known Centrally Acting Drug

The cholinergic anti-inflammatory pathway is one of the putative biochemical pathways that link diabetes with Alzheimer disease. Hence, we aimed to verify the potential antidiabetic effect of galantamine, unveil the possible mechanisms and evaluate its interaction with vildagliptin. The n5-STZ rat model was adopted and the diabetic animals were treated with galantamine and/or vildagliptin for 4 weeks. Galantamine lowered the n5-STZ-induced elevation in body weight, food/water intake, serum levels of glucose, fructosamine, and ALT/AST, as well as AChE in the tested organs. Moreover, it modulated successfully the lipid profile assessed in serum, liver, and muscle, and increased serum insulin level, as well as % β-cell function, in a pattern similar to that of vildagliptin. Additionally, galantamine confirmed its antioxidant (Nrf2, TAC, MDA), anti-inflammatory (NF-κB, TNF-α, visfatin, adiponectin) and anti-apoptotic (caspase-3, cytochrome c) capabilities by altering the n5-STZ effect on all the aforementioned parameters. On the molecular level, galantamine/vildagliptin have improved the insulin (p-insulin receptor, p-Akt, GLUT4/GLUT2) and Wnt/β-catenin (p-GSK-3β, β-catenin) signaling pathways. On almost all parameters, the galantamine effects surpassed that of vildagliptin, while the combination regimen showed the best effects. The present results clearly proved that galantamine modulated glucose/lipid profile possibly through its anti-oxidant, -apoptotic, -inflammatory and -cholinesterase properties. These effects could be attributed partly to the enhancement of insulin and Wnt/β-catenin signaling pathways. Galantamine can be strongly considered as a potential antidiabetic agent and as an add-on therapy with other oral antidiabetics.

Barnidipine or Lercanidipine on Echocardiographic Parameters in Hypertensive, Type 2 Diabetics with Left Ventricular Hypertrophy: A Randomized Clinical Trial

The aim of this study was to evaluate the effects of lercanidipine or barnidipine on echocardiographic parameters, in hypertensive, type 2 diabetics with left ventricular hypertrophy. One hundred and forty-four patients were randomized to lercanidipine, 20 mg/day, or barnidipine, 20 mg/day, in addition to losartan, 100 mg/day, for 6 months. We evaluated: blood pressure, fasting plasma glucose (FPG), glycated hemoglobin (HbA_1c), lipid profile, creatinine, estimated glomerular filtration rate (eGFR), sodium, potassium, and acid uric. Echocardiography was performed at baseline and after 6 months. Both lercanidipine and barnidipine decreased blood pressure. Left ventricular mass index was reduced to a greater extent with barnidipine + losartan. Interventricular septal thickness in diastole was reduced by barnidipine + losartan. Posterior wall thickness in diastole was decreased by both treatments, even if barnidipine + losartan were more effective. Ratio of peak early diastolic filling velocity to peak filling velocity at atrial contraction was increased by barnidipine + losartan, but not by lercanidipine + losartan. Finally, isovolumetric relaxation and time and left atrial volume index were reduced by barnidipine + losartan, while lercanidipine + losartan did not affect them. In conclusion, barnidipine + losartan provided a greater improvement of echocardiographic parameters compared to lercanidipine + losartan.

The efficacy and safety of DPP4 inhibitors compared to sulfonylureas as add-on therapy to metformin in patients with Type 2 diabetes: A systematic review and meta-analysis

There is no consensus on the selection of specific drug therapies when metformin fails in Type 2 diabetes (T2D). This meta-analysis was performed to determine the efficacy and safety of Dipeptidyl peptidase-4 inhibitors (DPP4-I) compared to sulfonylurea (SU) as add-on therapy to metformin in inadequately controlled T2D patients. We searched MEDLINE, CENTRAL, EMBASE, and CINAHL for randomized trials comparing DPP4-I to SU as add-on therapy to metformin and reported a change in hemoglobin A1c (HbA1c). Sixteen articles were included. There was a significantly greater reduction in HbA1c from baseline to 12 weeks with SU versus DPP4-I (MD[95% CI]=0.21%(2 mmol/mol) [0.06, 0.35]) but no significant difference at 52 and 104 weeks (MD[95% CI]=0.06%(-1 mmol/mol) [-0.03, 0.15] and 0.02%(-1 mmol/mol) [-0.13,0.18] respectively). SU was associated with weight gain and DPP4-I with weight loss at all time-points. The incidence of hypoglycemia at 12, 52, and 104 weeks was significantly greater with SU (20%, 24%, and 27% respectively) compared to DPP4-I (6%, 3%, and 4% respectively). The proportion of patients with HbA1c<7%(53 mmol/mol) without hypoglycemia was significantly higher at 52 and 104 weeks among patients on DPP4-I (RR[95% CI]=1.20 [1.05, 1.37] and 1.53 [1.16, 2.02] respectively). There was no significant difference between the two groups in the incidence of other side effects. While both SU and DPP4-I can be considered as options for add-on therapy to metformin in inadequately controlled T2D, SU results in a significantly increased risk of hypoglycemia and weight gain. By contrast, DPP4-I produce 0.4-0.6% (4-7 mmol/mol) reduction in HbA1c, lower risk of hypoglycemia, and weight loss.

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.

Effect of vildagliptin on hepatic steatosis

CONTEXT

Although dipeptidyl-peptidase-4 inhibitors exert their major action via an incretin mechanism, a favorable effect of vildagliptin on lipid metabolism remains unexplained.

OBJECTIVE

The objective was to examine hepatic triglyceride levels and insulin sensitivity on vildagliptin.

DESIGN

This was a 6-month, randomized, double-blind, placebo-controlled trial.

SETTING

This was an outpatient study at a university clinical research center.

PATIENTS

Individuals with type 2 diabetes (n = 44) and glycated hemoglobin ≤ 7.6% on stable metformin therapy were included.

INTERVENTION

Intervention was vildagliptin 50 mg twice a day or placebo over 6 months.

MAIN OUTCOME MEASURES

Main outcome measures were hepatic triglyceride levels and insulin sensitivity.

RESULTS

Mean fasting liver triglyceride content decreased by 27% with vildagliptin, from 7.3 ± 1.0% (baseline) to 5.3 ± 0.9% (endpoint). There was no change in the placebo group. The between-group difference in change from baseline was significant (P = .013). Mean fasting plasma glucose concentration decreased over the study period with vildagliptin vs placebo by -1.0 mmol/L (P = .018), and there was a positive correlation between these decrements and liver triglyceride in the vildagliptin group at 3 months (r = 0.47; P = .02) and 6 months (r = 0.44; P = .03). Plasma alanine aminotransferase fell from 27.2 ± 2.8 to 20.3 ± 1.4 IU/L in the vildagliptin group (P = .0007), and there was a correlation between the decrements in alanine aminotransferase and liver triglyceride (r = 0.83; P < .0001). Insulin sensitivity during the euglycemic clamp was similar in each group at baseline (3.24 ± 0.30 vs 3.19 ± 0.38 mg/kg/min) and did not change (adjusted mean change of 0.26 ± 0.22 vs 0.32 ± 0.22 mg/kg/min; P = .86). Mean body weight decreased by 1.6 ± 0.5 vs 0.4 ± 0.5 kg in the vildagliptin and placebo groups, respectively (P = .08).

CONCLUSIONS

This study demonstrates that the dipeptidyl-peptidase-4 inhibitor vildagliptin brings about a clinically significant decrease in hepatic triglyceride levels during 6 months of therapy unrelated to change in body weight. There was no change in peripheral insulin sensitivity.

Characterisation of pain responses in the high fat diet/streptozotocin model of diabetes and the analgesic effects of antidiabetic treatments

Chronic pain is a common complication of diabetes. The aim of the present study was to characterise pain behaviour in a high fat diet/streptozotocin (HFD/STZ) model of diabetes in the rat, investigate spinal mechanisms, and determine the effects of antidiabetic interventions. Three-week consumption of a high fat diet followed by single injection of STZ (45 mgkg(-1)) produced sustained changes in plasma insulin and glucose until day 120. Hindpaw mechanical withdrawal thresholds were significantly lowered in the model, but mechanically evoked responses of spinal neurones were unaltered, compared to HFD/vehicle rats. HFD/STZ rats had significantly lower numbers of spinal Iba-1 positive cells (morphologically identified as activated microglia) and spinal GFAP immunofluorescence (a marker of astrogliosis) in the spinal cord at day 50, compared to time-matched controls. The PPARγ ligand pioglitazone (10 mgkg(-1)) did not alter HFD/STZ induced metabolic changes or hindpaw withdrawal thresholds of HFD/STZ rats. Daily linagliptin (3 mgkg(-1)) and metformin (200 mgkg(-1)) from day 4 after model induction did not alter plasma glucose or insulin in HFD/STZ rats but significantly prevented changes in the mechanical withdrawal thresholds. The demonstration that currently prescribed antidiabetic drugs prevent aberrant pain behaviour supports the use of this model to investigate pain mechanisms associated with diabetes.