A randomized trial of rosiglitazone therapy in patients with inadequately controlled insulin-treated type 2 diabetes

A pan-PPAR agonist E17241 ameliorates hyperglycemia and diabetic dyslipidemia in KKAy mice via up-regulating ABCA1 in islet, liver, and white adipose tissue

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a common chronic metabolic disease. Peroxisome proliferator-activated receptors (PPARs) play crucial roles in regulating glucolipid metabolism. Previous studies showed that E17241 could ameliorate atherosclerosis and lower fasting blood glucose levels in ApoE-/- mice. In this work, we investigated the role of E17241 in glycolipid metabolism in diabetic KKAy mice.

APPROACH AND RESULTS

We confirmed that E17241 is a powerful pan-PPAR agonist with a potent agonistic activity on PPARγ, a high activity on PPARα, and a moderate activity on PPARδ. E17241 also significantly increased the protein expression of ATP-binding cassette transporter 1 (ABCA1), a crucial downstream target gene for PPARs. E17241 clearly lowered plasma glucose levels, improved OGTT and ITT, decreased islet cholesterol content, improved β-cell function, and promoted insulin secretion in KKAy mice. Moreover, E17241 could significantly lower plasma total cholesterol and triglyceride levels, reduce liver lipid deposition, and improve the adipocyte hypertrophy and the inflammatory response in epididymal white adipose tissue. Further mechanistic studies indicated that E17241 boosts cholesterol efflux and insulin secretion in an ABCA1 dependent manner. RNA-seq and qRT-PCR analysis demonstrated that E17241 induced different expression of PPAR target genes in liver and adipose tissue differently from the PPARγ agonist rosiglitazone. In addition, E17241 treatment was also demonstrated to have an exhilarating cardiorenal benefits.

CONCLUSIONS

Our results demonstrate that E17241 regulates glucolipid metabolism in KKAy diabetic mice while having cardiorenal benefits without inducing weight gain. It is a promising drug candidate for the treatment of T2DM.

[Non-Insulin Antidiabetic Agents in the Management of Hyperglycaemia of Non-Critical Hospitalized Patients]

Hyperglycaemia affects more than 30% of adults hospitalized for non-critical illness and is associated with an increased risk of adverse clinical outcomes. Insulin therapy is widely used for its safety and efficacy. However, given the growing availability of new drugs and new classes of antidiabetic agents with benefits beyond glycaemic control, challenges arise regarding their use in the hospital setting. This article aims to review and summarize the most recently available evidence and recommendations on the role of non-insulin antidiabetic agents in the management of hyperglycaemia in hospitalized patients. Insulin therapy remains the method of choice. Dipeptidyl peptidase 4 inhibitors can be considered in mild to moderate hyperglycaemia. Glucagon-like peptide 1 receptor agonists have recently shown promising results, with high efficacy in glycaemic control and low risk of hypoglycaemia. There are concerns regarding the increased risk of acidosis with metformin use, especially in cases of acute illness, although there is no evidence to support its suspension in selected patients with relative clinical stability. Sodium-glucose cotransporter-2 inhibitors should be discontinued in clinical situations that may predispose to ketoacidosis, including episodes of acute illness. The hospital use of sulfonylureas and thiazolidinediones is not advised.

The Modulatory Bioeffects of Pomegranate (Punica granatum L.) Polyphenols on Metabolic Disorders: Understanding Their Preventive Role against Metabolic Syndrome

Modern research achievements support the health-promoting effects of natural products and diets rich in polyphenols. Pomegranate (PG) (Punica granatum L.) contains a considerable number of bioactive compounds that exert a broad spectrum of beneficial biological activities, including antimicrobial, antidiabetic, antiobesity, and atheroprotective properties. In this context, the reviewed literature shows that PG intake might reduce insulin resistance, cytokine levels, redox gene expression, blood pressure elevation, vascular injuries, and lipoprotein oxidative modifications. The lipid parameter corrective capabilities of PG-ellagitannins have also been extensively reported to be significantly effective in reducing hyperlipidemia (TC, LDL-C, VLDL-C, and TAGs), while increasing plasma HDL-C concentrations and improving the TC/HDL-C and LDL-C/HDL-C ratios. The health benefits of pomegranate consumption seem to be acheived through the amelioration of adipose tissue endocrine function, fatty acid utilization, GLUT receptor expression, paraoxonase activity enhancement, and the modulation of PPAR and NF-κB. While the results from animal experiments are promising, human findings published in this field are inconsistent and are still limited in several aspects. The present review aims to discuss and provide a critical analysis of PG's bioeffects on the components of metabolic syndrome, type-2 diabetes, obesity, and dyslipidemia, as well as on certain cardiovascular-related diseases. Additionally, a brief overview of the pharmacokinetic properties, safety, and bioavailability of PG-ellagitannins is included.

2022 update to the position statement by Primary Care Diabetes Europe: a disease state approach to the pharmacological management of type 2 diabetes in primary care

Type 2 diabetes and its associated comorbidities are growing more prevalent, and the complexity of optimising glycaemic control is increasing, especially on the frontlines of patient care. In many countries, most patients with type 2 diabetes are managed in a primary care setting. However, primary healthcare professionals face the challenge of the growing plethora of available treatment options for managing hyperglycaemia, leading to difficultly in making treatment decisions and contributing to treatment and therapeutic inertia. This position statement offers a simple and patient-centred clinical decision-making model with practical treatment recommendations that can be widely implemented by primary care clinicians worldwide through shared-decision conversations with their patients. It highlights the importance of managing cardiovascular disease and elevated cardiovascular risk in people with type 2 diabetes and aims to provide innovative risk stratification and treatment strategies that connect patients with the most effective care.

Anti-Diabetic Potentials of Thiazolidinedione Analogues with Efficient Synthetic Procedures: A Review of Literature

Background::

Diabetes mellitus refers to one of the leading cause of diseases that affect large populations of human and is characterized by a high glucose level in the blood (also known as hyperglycemia). Thiazolidinedione (TZD) is a five-member heterocyclic compound consisting of three carbons, nitrogen and sulfur. It is also known as glitazones, can be used as potent hypoglycemic agents and is also reduce many other cardiovascular risk factors including percutaneous coronary intervention, carotid and coronary atherosclerosis. As it plays a very important role in the field of medicinal chemistry or pharmaceutical sciences, novel medicine developed and many are on underdevelopment, these derivatives have thiazolidinedione as their primary nucleus.

Objective::

This article has discussed the different synthetic procedures of thiazolidinediones that exhibited potential antidiabetic activity by the activation of PPAR-γ, by reducing the blood glucose levels and by different metabolic process incorporation.

Conclusion::

Thiazolidinediones has effective profile as the future investigational drug and can be processed in drug discovery because of its efficient anti-diabetic potential.

Relation of cardiac function to insulin resistance as evaluated by hyperinsulinemic-euglycemic clamp analysis in individuals with type 2 diabetes

AIMS

Whereas homeostasis model assessment of insulin resistance (HOMA-IR), an easily measured but limited index of insulin resistance, has been shown to correlate with impairment of cardiac function in individuals without diabetes, the pathological relevance of insulin resistance to the development of cardiac dysfunction in individuals with type 2 diabetes has remained unclear. Here we investigated the relation between left ventricular (LV) function as assessed by echocardiography and insulin resistance as evaluated by hyperinsulinemic-euglycemic clamp analysis, the gold standard for measurement of this parameter, in individuals with type 2 diabetes.

METHODS

This retrospective study included 34 individuals with type 2 diabetes who underwent both hyperinsulinemic-euglycemic clamp analysis and echocardiography. Both the insulin sensitivity index (ISI) as determined by glucose clamp analysis as well as HOMA-IR were determined as measures of insulin resistance. The ratio of the peak early- to late-diastolic mitral inflow velocities (E/A) and the LV ejection fraction (LVEF) were determined as measures of diastolic and systolic function, respectively.

RESULTS

The ISI was significantly correlated with both the E/A ratio and LVEF (correlation coefficients of 0.480 and 0.360, respectively), whereas HOMA-IR was not correlated with either cardiac parameter. Multivariate analysis revealed that ISI was an independent predictor for both a high log [E/A] (P = 0.031) and a high LVEF (P = 0.045).

CONCLUSIONS

Insulin resistance as evaluated by hyperinsulinemic-euglycemic clamp analysis may be causally related to LV diastolic and systolic dysfunction in individuals with type 2 diabetes.

Cellular mechanisms and recommended drug-based therapeutic options in diabetic cardiomyopathy

Diabetes mellitus (DM) is associated with a specific cardiac phenotype characterized by structural and functional alterations. This so-called diabetic cardiomyopathy (DM CM) is clinically relevant as patients with DM show high incidence of heart failure. Mechanistically, several parameters interact on the cardiomyocyte level leading to increased inflammation, apoptosis, reactive oxygen species and altered calcium signaling. This in turn provokes functional myocardial changes that might inter alia play into the worsened clinical outcome in DM patients. Therefore, efficient therapeutic options are urgently needed. This review focuses on mechanistic effects of currently recommended antidiabetic treatment and heart failure therapy for DM CM.

A randomized, placebo-controlled study to evaluate the efficacy and safety of adding omarigliptin to insulin therapy in Japanese patients with type 2 diabetes and inadequate glycaemic control

AIM

To evaluate the efficacy and safety of adding the once-weekly oral dipeptidyl peptidase-4 inhibitor omarigliptin to treatment of Japanese patients with type 2 diabetes and inadequate glycaemic control on insulin monotherapy.

MATERIALS AND METHODS

In a 52-week clinical trial, Japanese patients on insulin monotherapy were randomized to once-weekly omarigliptin 25 mg (N = 123) or placebo (N = 61) for a 16-week, double-blind, placebo-controlled period. After Week 16, patients continued or switched to omarigliptin for a 36-week open-label period.

RESULTS

From a mean baseline of approximately 8.8%, the Week 16 least squares mean changes in HbA1c were -0.61% (omarigliptin) and 0.29% (placebo); the between-group difference was -0.90% (p < .001). At Week 52, the mean change from baseline in HbA1c was -0.57% in both the group on omarigliptin for 52 weeks and the group on omarigliptin for 36 weeks (switched from placebo at Week 16). During the first 16 weeks of treatment, the incidences of adverse events (AEs), serious AEs, drug-related AEs and discontinuation from trial medication because of an AE were similar in both groups. A slight increase in incidence of symptomatic hypoglycaemia was observed in the omarigliptin group (n = 13 [10.6%]) compared with placebo (n = 4 [6.6%]). No severe hypoglycaemia was reported during the study. No new safety signals emerged with treatment beyond Week 16 through Week 52.

CONCLUSION

The addition of once-weekly omarigliptin to insulin therapy for up to 52 weeks was generally well tolerated and provided clinically meaningful improvement in glycaemic control throughout the trial period. ClinicalTrials.gov: NCT02906709.

A disease state approach to the pharmacological management of Type 2 diabetes in primary care: A position statement by Primary Care Diabetes Europe

Type 2 diabetes and its associated comorbidities are growing more prevalent, and the complexity of optimising glycaemic control is increasing, especially on the frontlines of patient care. In many countries, most patients with type 2 diabetes are managed in a primary care setting. However, primary healthcare professionals face the challenge of the growing plethora of available treatment options for managing hyperglycaemia, leading to difficultly in making treatment decisions and contributing to therapeutic inertia. This position statement offers a simple and patient-centred clinical decision-making model with practical treatment recommendations that can be widely implemented by primary care clinicians worldwide through shared-decision conversations with their patients. It highlights the importance of managing cardiovascular disease and elevated cardiovascular risk in people with type 2 diabetes and aims to provide innovative risk stratification and treatment strategies that connect patients with the most effective care.

Age, sex, disease severity, and disease duration difference in placebo response: implications from a meta-analysis of diabetes mellitus

BACKGROUND

The placebo response in patients with diabetes mellitus is very common. A systematic evaluation needs to be updated with the current evidence about the placebo response in diabetes mellitus and the associated factors in clinical trials of anti-diabetic medicine.

METHODS

Literature research was conducted in Medline, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for studies published between the date of inception and June 2019. Randomized placebo-controlled trials conducted in type 1and type 2 diabetes mellitus (T1DM/T2DM) were included. Random-effects model and meta-regression analysis were accordingly used. This meta-analysis was registered in PROSPERO as CRD42014009373.

RESULTS

Significantly weight elevation (effect size (ES) = 0.33 kg, 95% CI, 0.03 to 0.61 kg) was observed in patients with placebo treatments in T1DM subgroup while significantly HbA1c reduction (ES = - 0.12%, 95% CI, - 0.16 to - 0.07%) and weight reduction (ES = - 0.40 kg, 95% CI, - 0.50 to - 0.29 kg) were observed in patients with placebo treatments in T2DM subgroup. Greater HbA1c reduction was observed in patients with injectable placebo treatments (ES = - 0.22%, 95% CI, - 0.32 to - 0.11%) versus oral types (ES = - 0.09%, 95% CI, - 0.14 to - 0.04%) in T2DM (P = 0.03). Older age (β = - 0.01, 95% CI, - 0.02 to - 0.01, P < 0.01) and longer diabetes duration (β = - 0.02, 95% CI, - 0.03 to - 0.21 × 10^-2, P = 0.03) was significantly associated with more HbA1c reduction by placebo in T1DM. However, younger age (β = 0.02, 95% CI, 0.01 to 0.03, P = 0.01), lower male percentage (β = 0.01, 95% CI, 0.22 × 10^-2, 0.01, P < 0.01), higher baseline BMI (β = - 0.02, 95% CI, - 0.04 to - 0.26 × 10^-2, P = 0.02), and higher baseline HbA1c (β = - 0.09, 95% CI, - 0.16 to - 0.01, P = 0.02) were significantly associated with more HbA1c reduction by placebo in T2DM. Shorter diabetes duration (β = 0.06, 95% CI, 0.06 to 0.10, P < 0.01) was significantly associated with more weight reduction by placebo in T2DM. However, the associations between baseline BMI, baseline HbA1c, and placebo response were insignificant after the adjusted analyses.

CONCLUSION

The placebo response in diabetes mellitus was systematically outlined. Age, sex, disease severity (indirectly reflected by baseline BMI and baseline HbA1c), and disease duration were associated with placebo response in diabetes mellitus. The association between baseline BMI, baseline HbA1c, and placebo response may be the result of regression to the mean.

A Review of Cardiovascular Outcomes Trials of Glucose-Lowering Therapies and Their Effects on Heart Failure Outcomes

Type 2 diabetes mellitus has long been recognized as a major risk factor for adverse atherosclerotic cardiovascular disease events; however, recent data indicate that heart failure is now emerging as the most common and morbid cardiovascular complication of type 2 diabetes mellitus. When heart failure develops in patients with type 2 diabetes, prognosis is ominous, highlighting the need for glucose-lowering therapies that can prevent heart failure, improve outcomes, or both. Prior to 2008, there was a paucity of randomized controlled trials evaluating long-term cardiovascular outcomes with glucose-lowering therapies. This changed after guidance on the assessment of novel glucose-lowering agents was issued by both the US Food and Drug Administration and the European Medicines Agency. Since then, significant progress has been made as a result of large cardiovascular outcomes trials. Though randomized controlled trials on insulin, sulfonylureas, and metformin are still limited, cardiovascular outcomes trials on newer glucose-lowering agents have included hundreds of thousands of patients with multiple years of follow-up. The increased risk of thiazolidinediones on heart failure had been well theorized and is now established; however, the increase in heart failure hospitalization with certain dipeptidyl peptidase-4 inhibitors was unexpected. The reasons for discrepancies with regard to heart failure risk with different dipeptidyl peptidase-4 inhibitors remain unclear, and further mechanistic studies are ongoing. The role of glucagon-like peptide-1 receptor agonists among patients with heart failure also remains unclear, and their effects may differ in patients with and without established heart failure, particularly those with decompensated heart failure with reduced ejection fraction.

Heart Failure in Type 2 Diabetes Mellitus

Patients with diabetes mellitus have >2× the risk for developing heart failure (HF; HF with reduced ejection fraction and HF with preserved ejection fraction). Cardiovascular outcomes, hospitalization, and prognosis are worse for patients with diabetes mellitus relative to those without. Beyond the structural and functional changes that characterize diabetic cardiomyopathy, a complex underlying, and interrelated pathophysiology exists. Despite the success of many commonly used antihyperglycemic therapies to lower hyperglycemia in type 2 diabetes mellitus the high prevalence of HF persists. This, therefore, raises the possibility that additional factors beyond glycemia might contribute to the increased HF risk in diabetes mellitus. This review summarizes the state of knowledge about the impact of existing antihyperglycemic therapies on HF and discusses potential mechanisms for beneficial or deleterious effects. Second, we review currently approved pharmacological therapies for HF and review evidence that addresses their efficacy in the context of diabetes mellitus. Dysregulation of many cellular mechanisms in multiple models of diabetic cardiomyopathy and in human hearts have been described. These include oxidative stress, inflammation, endoplasmic reticulum stress, aberrant insulin signaling, accumulation of advanced glycated end-products, altered autophagy, changes in myocardial substrate metabolism and mitochondrial bioenergetics, lipotoxicity, and altered signal transduction such as GRK (g-protein receptor kinase) signaling, renin angiotensin aldosterone signaling and β-2 adrenergic receptor signaling. These pathophysiological pathways might be amenable to pharmacological therapy to reduce the risk of HF in the context of type 2 diabetes mellitus. Successful targeting of these pathways could alter the prognosis and risk of HF beyond what is currently achieved using existing antihyperglycemic and HF therapeutics.

The influence of anti-hyperglycemic drug therapy on cardiovascular and heart failure outcomes in patients with type 2 diabetes mellitus

Patients with type 2 diabetes mellitus (DM) are at a substantially increased risk of heart failure (HF) and HF mortality. Despite the lack of evidence that tight glycemic control reduces the incidence of cardiovascular (CV) events, a growing body of evidence suggests that the choice of glucose-lowering agents may influence outcomes including HF. Thiazolidinediones are associated with a significant risk of HF. For metformin, sulphonylureas and insulin, little data is available to indicate the impact on HF. The glucagon-like peptide-1 (GLP-1) agonists, liraglutide and semaglutide, have been shown to reduce major CV events, but did not affect rates of hospitalization for HF. Clinical trials have demonstrated diverse effects of Dipeptidyl peptidase-4 (DPP-4) inhibitors on HF; saxagliptin showed an increased risk of HF admissions, alogliptin was associated with higher rates of new HF admissions, while sitagliptin had a neutral effect. The sodium-glucose cotransporter 2 (SGLT2) inhibitors, empagliflozin and canagliflozin, have been recently shown to reduce the incidence of HF and cardiovascular mortality in patients with and without a history of HF. This review will summarize key findings of the impact of glucose-lowering agents on CV safety and HF-associated outcomes, present available data on the underlying mechanisms for the benefits of the SGLT2 inhibitors on HF, and discuss strategies to improve outcomes in patients with DM and high CV risk.

Electrophilic nitro-oleic acid reverses obesity-induced hepatic steatosis

Non-alcoholic fatty liver disease (NAFLD) is linked to obesity and insulin resistance and is the most prevalent chronic liver disease. During the development of obesity and NAFLD, mitochondria adapt to the increased lipid load in hepatocytes by increasing the rate of fatty acid oxidation. In concert with this, reactive species (RS) generation is increased, damaging hepatocytes and inducing inflammation. Hepatic mitochondrial dysfunction is central to the pathogenesis of NAFLD via undefined mechanisms. There are no FDA approved treatments for NAFLD other than weight loss and management of glucose tolerance. Electrophilic nitro-oleic acid (NO₂-OA) displays anti-inflammatory and antioxidant signaling actions, thus mitochondrial dysfunction, RS production and inflammatory responses to NO₂-OA and the insulin sensitizer rosiglitazone were evaluated in a murine model of insulin resistance and NAFLD. Mice on HFD for 20 wk displayed increased adiposity, insulin resistance and hepatic lipid accumulation (steatosis) compared to mice on normal chow (NC). The HFD mice had mitochondrial dysfunction characterized by lower hepatic mitochondrial complex I, IV and V activity compared to mice on NC. Treatment with NO₂-OA or rosiglitazone for the last 42 days (out of 20 wk) abrogated HFD-mediated decreases in hepatic mitochondrial complex I, IV and V activity. Notably, NO₂-OA treatment normalized hepatic triglyceride levels and significantly reversed hepatic steatosis. Despite the improved glucose tolerance observed upon rosiglitazone treatment, liver weight and hepatic triglycerides were significantly increased over vehicle-treated HFD mice. These observations support that the pleiotropic signaling actions of electrophilic fatty acids limit the complex hepatic and systemic pathogenic responses instigated by obesity, without the adverse effects of thiazolidinedione drugs such as rosiglitazone.

A randomized clinical trial of the efficacy and safety of sitagliptin compared with dapagliflozin in patients with type 2 diabetes mellitus and mild renal insufficiency: The CompoSIT-R study

AIM

To compare the efficacy and safety of the dipeptidyl peptidase-4 inhibitor sitagliptin with the sodium-glucose transporter-2 inhibitor dapagliflozin in patients with type 2 diabetes and mild renal insufficiency.

MATERIALS AND METHODS

Patients with HbA1c ≥7.0 to ≤9.5% (≥53 to ≤80 mmol/mol) and estimated glomerular filtration rate ≥60 to <90 mL/min/1.73m² on metformin (≥1500 mg/d) ± sulfonylurea were randomized to sitagliptin 100 mg (n = 307) or dapagliflozin 5 mg titrated to 10 mg (n = 306) once daily for 24 weeks. A longitudinal data analysis model was used to test the primary hypothesis that sitagliptin is non-inferior to dapagliflozin in reducing HbA1c at Week 24, with superiority to be tested if non-inferiority is met. ClinicalTrials.gov NCT02532855.

RESULTS

Baseline mean HbA1c (% [mmol/mol]) was 7.7 (60.9) and 7.8 (61.2), and mean eGFR (mL/min/1.73m² ) was 79.4 and 76.9 for the sitagliptin and dapagliflozin groups, respectively. After 24 weeks, the between-group difference in least squares mean (95% CI) changes from baseline in HbA1c was -0.15% (-0.26, -0.04) (-1.67 mmol/mol [-2.86, -0.48]), P = 0.006, meeting the prespecified criteria for declaring both non-inferiority and superiority of sitagliptin versus dapagliflozin. The HbA1c goal of <7% (<53 mmol/mol) was met by 43% (sitagliptin) and 27% (dapagliflozin) of patients. No meaningful between-group difference was observed in a pre-specified analysis of 2-hour incremental postprandial glucose excursion. A review of adverse events (AEs) was notable for a lower incidence of drug-related AEs with sitagliptin compared with dapagliflozin.

CONCLUSIONS

In patients with type 2 diabetes, mild renal insufficiency and inadequate glycaemic control on metformin ± sulfonylurea, sitagliptin treatment resulted in greater improvement in glycaemic control compared with dapagliflozin and was generally well tolerated.

Immense Insulin Intestinal Uptake and Lymphatic Transport Using Bile Acid Conjugated Partially Uncapped Liposome

We provide immense insulin absorption from the gastrointestinal tract, combining apical sodium-dependent bile acid transporter-mediated intestinal uptake and the lymphatic transport pathway. This strategy has proven to employ chondroitin sulfate- g-taurocholic acid coated, insulin-loaded partially uncapped liposome (IPUL-CST) for type 1 diabetes mellitus (T1DM) treatment. The loading efficiency of insulin in IPUL-CST increased significantly from 33% to 75% via the partially uncapped liposome preparation method. Moreover, the IPUL-CST revealed an improved insulin protection efficacy in GIT simulated pH and digestive enzyme conditions. The high dose of IPUL-CST in the small intestine was detected 4 h post-oral administration using ex vivo optical imaging and fluorescence intensity. The IPUL-CST exhibited significantly enhanced intestinal absorption (oral bioavailability, 34%; T_max, 9 h) and reduced blood glucose levels for 16 h in T1DM. The results demonstrated that the new investigated IPUL-CST is a promising carrier for oral insulin delivery.

Medications that cause weight gain and alternatives in Canada: a narrative review

BACKGROUND

The cause of the obesity epidemic is multifactorial, but may, in part, be related to medication-induced weight gain. While clinicians may strive to do their best to select pharmacotherapy(ies) that has the least negative impact on weight, the literature regarding the weight effects of medication is often limited and devoid of alternative therapies.

RESULTS

Antipsychotics, antidepressants, antihyperglycemics, antihypertensives and corticosteroids all contain medications that were associated with significant weight gain. However, there are several medication alternatives within the majority of these classes associated with weight neutral or even weight loss effects. Further, while not all of the classes of medication examined in this review have weight-favorable alternatives, there exist many other tools to mitigate weight gain associated with medication use, such as changes in dosing, medication delivery or the use of adjunctive therapies.

CONCLUSION

Medication-induced weight gain can be frustrating for both the patient and the clinician. As the use of pharmaceuticals continues to increase, it is pertinent for clinicians to consider the weight effects of medications prior to prescribing or in the course of treatment. In the case where it is not feasible to make changes to medication, adjunctive therapies should be considered.

Effects of lobeglitazone on insulin resistance and hepatic steatosis in high-fat diet-fed mice

Lobeglitazone (Lobe) is a novel thiazolidinedione antidiabetic drug that reduces insulin resistance by activating peroxisome proliferator-activated receptor-gamma (PPARγ). However, the exact mechanisms of antidiabetic effects of Lobe have not been established in an animal model. The aim of this study was to evaluate the hypoglycemic effects of Lobe and investigate possible factors involved in Lobe-enhanced hepatic steatosis in high-fat diet (HFD)-fed mice. Mice were fed an HFD for 15 weeks. Lobe was administrated orally during the last 9 weeks. Lobe treatment significantly reduced insulin resistance and increased expression of hepatic glucose transporter 4 (GLUT4) and PPARs in HFD-fed mice. However, increased body weight and hepatic steatosis were not reduced by Lobe in these mice. Metabolomics fingerprinting showed that several lipogenesis-related hepatic and serum metabolites in HFD-fed mice had positive or negative correlations with Lobe administration. In particular, increased leptin levels during HFD were further increased by Lobe. HFD-induced signaling transducer and activator of transcription 3 (STAT3) phosphorylation in the hypothalamus was increased by Lobe. In addition, immunohistochemical analysis showed more proopiomelanocortin (POMC)-positive neurons in the hypothalamus of HFD-fed mice (with or without Lobe) compared with normal diet-fed mice. Despite improving leptin signaling in the hypothalamus and enhancing insulin sensitivity in HFD-fed mice, Lobe increased body weight and steatosis. Further research is necessary regarding other factors affecting Lobe-enhanced hepatic steatosis and hyperphagia.

Addition of dipeptidyl peptidase-4 inhibitors to insulin treatment in type 2 diabetes patients: A meta-analysis

AIMS/INTRODUCTION

To evaluate the efficacy and safety of combining insulin therapy with dipeptidyl peptidase-4 (DPP-4) inhibitors compared with combining insulin therapy with a placebo or other antihyperglycemic agents.

MATERIALS AND METHODS

A literature search was carried out via electronic databases. The inclusion criteria were randomized controlled trials comparing the addition of DPP-4 inhibitors to insulin with the addition of a placebo or other active hypoglycemic agents to insulin therapy, study duration of no less than 12 weeks carried out in type 2 diabetes patients and the availability of outcome data to evaluate a change in the glycated hemoglobin.

RESULTS

The glycated hemoglobin-lowering efficacy was significantly greater with DPP-4 inhibitor/insulin (DPP-4i/INS) than with placebo/insulin (weighted mean difference -0.53%, 95% confidence interval -0.63, -0.43, P < 0.01). The postprandial plasma glucose-lowering efficacies was also significantly greater with DPP-4i/INS than with placebo/insulin (weighted mean difference -1.65 mmol/L, 95% CI: -2.34, -0.96, P < 0.05). The risk of hypoglycemia or severe hypoglycemia was similar for DPP4i/INS and placebo/insulin treatments. There was no significant difference in the glycemia-lowering efficacy between DPP-4i/INS and alpha-glucosidase inhibitors/insulin, thiazolidinedione/insulin and glucagon-like peptide-1 receptor agonist/insulin. Sodium-glucose cotransporter 2 inhibitor/insulin treatment achieved better placebo-corrected efficacy in lowering postprandial plasma glucose, with less weight gain and no higher risk of hypoglycemia.

CONCLUSIONS

Treatment with DPP-4 inhibitors combined with insulin improved glycemic control without an increased risk of hypoglycemia or weight gain compared with insulin treatment alone.

Effect of Hexadecyl Azelaoyl Phosphatidylcholine on Cardiomyocyte Apoptosis in Myocardial Ischemia-Reperfusion Injury: A Hypothesis

Reperfusion after myocardial ischemia can induce cardiomyocyte death, known as myocardial reperfusion injury. The pathophysiology of the process of reperfusion suggests the confluence multiple pathways. Recent studies have focused on the inflammatory response, which is considered to be the main mechanism during the process of myocardial ischemia-reperfusion injury and can cause cardiomyocyte apoptosis. Peroxisome proliferator-activated receptors gamma activated by endogenous ligands and exogenous ligand can decrease the inflammatory response in cardiomyocytes. Thiazolidinediones are synthetic, high-affinity, selective ligands for peroxisome proliferator-activated receptors gamma, and can inhibit the inflammatory response, decrease myocardial infarct size, and protect cardiac function. However, thiazolidinediones, including rosiglitazone and pioglitazone, can also contribute to adverse cardiovascular events such as congestive heart failure. Therefore, there are some limitations to the use of thiazolidinediones. Most endogenous ligands were of low affinity until hexadecyl azelaoyl phosphatidylcholine was identified as a high-affinity ligand and agonist for peroxisome proliferator-activated receptors gamma. Hexadecyl azelaoyl phosphatidylcholine binds recombinant peroxisome proliferator-activated receptors with an affinity (Kd(app) ≈40 nM) which is equivalent to rosiglitazone. Therefore, hexadecyl azelaoyl phosphatidylcholine is a specific peroxisome proliferator-activated receptors gamma agonist. Given these findings, we hypothesized that the use of hexadecyl azelaoyl phosphatidylcholine can activate the peroxisome proliferator-activated receptors gamma signal pathways and prevent the inflammatory response process of myocardial ischemia-reperfusion injury, with reduced cardiomyocyte apoptosis and death.

Comparison of non-insulin antidiabetic agents as an add-on drug to insulin therapy in type 2 diabetes: a network meta-analysis

We aimed to evaluate the comparative efficacy and safety of dipeptidyl peptidase-4 inhibitors (DPP4i), glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose co-transporter 2 inhibitors (SGLT2i), or thiazolidinedione (TZD) as an adjunctive treatment in patients with poorly controlled type 2 diabetes mellitus (T2DM) on insulin therapy. We searched Medline, Embase, the Cochrane Library, and ClinicalTrials.gov through April 2016. Bayesian network meta-analyses were performed with covariate adjustment. The primary outcome was the change in glycated hemoglobin A1c (HbA1c) from baseline. Fifty randomized controlled trials covering 15,494 patients were included. GLP-1RA showed the greatest HbA1c-lowering effect compared to the control (−0.84%; 95% credible interval, −1.00% to −0.69%), followed by TZD (−0.73%; −0.93 to −0.52%), SGLT2i (−0.66%; −0.84% to −0.48%), and DPP4i (−0.54%; −0.68% to −0.39%). SGLT2i showed the greatest fasting plasma glucose reduction. GLP-1RA and SGLT2i showed greater body weight reduction, whereas TZD increased body weight. TZD was ranked the highest in terms of insulin dose reduction. The risk of hypoglycemia was increased with TZD or GLP-1RA. The study provides the best available evidence on the comparative efficacy and safety of non-insulin anti-diabetic agents on top of pre-existing insulin therapy for inadequately controlled T2DM patients.

Management Strategies for Posttransplant Diabetes Mellitus after Heart Transplantation: A Review

Posttransplant diabetes mellitus (PTDM) is a well-recognized complication of heart transplantation and is associated with increased morbidity and mortality. Previous studies have yielded wide ranging estimates in the incidence of PTDM due in part to variable definitions applied. In addition, there is a limited published data on the management of PTDM after heart transplantation and a paucity of studies examining the effects of newer classes of hypoglycaemic drug therapies. In this review, we discuss the role of established glucose-lowering therapies and the rationale and emerging clinical evidence that supports the role of incretin-based therapies (glucagon like peptide- (GLP-) 1 agonists and dipeptidyl peptidase- (DPP-) 4 inhibitors) and sodium-glucose cotransporter 2 (SGLT2) inhibitors in the management of PTDM after heart transplantation. Recently published Consensus Guidelines for the diagnosis of PTDM will hopefully lead to more consistent approaches to the diagnosis of PTDM and provide a platform for the larger-scale multicentre trials that will be needed to determine the role of these newer therapies in the management of PTDM.

Thiazolidinedione drugs in the treatment of type 2 diabetes mellitus: past, present and future

Thiazolidinedione (TZD) drugs used in the treatment of type 2 diabetes mellitus (T2DM) have proven effective in improving insulin sensitivity, hyperglycemia, and lipid metabolism. Though well tolerated by some patients, their mechanism of action as ligands of peroxisome proliferator-activated receptors (PPARs) results in the activation of several pathways in addition to those responsible for glycemic control and lipid homeostasis. These pathways, which include those related to inflammation, bone formation, and cell proliferation, may lead to adverse health outcomes. As treatment with TZDs has been associated with adverse hepatic, cardiovascular, osteological, and carcinogenic events in some studies, the role of TZDs in the treatment of T2DM continues to be debated. At the same time, new therapeutic roles for TZDs are being investigated, with new forms and isoforms currently in the pre-clinical phase for use in the prevention and treatment of some cancers, inflammatory diseases, and other conditions. The aims of this review are to provide an overview of the mechanism(s) of action of TZDs, a review of their safety for use in the treatment of T2DM, and a perspective on their current and future therapeutic roles.

Sitagliptin added to stable insulin therapy with or without metformin in Chinese patients with type 2 diabetes

Introduction

We evaluated the tolerability and efficacy of the addition of sitagliptin in Chinese patients with type 2 diabetes mellitus receiving stable insulin therapy alone or in combination with metformin.

Materials and Methods

A total of 467 patients with inadequate glycemic control on insulin (glycated hemoglobin [HbA1c] ≥7.5% and ≤11%) were randomized 1:1 to receive sitagliptin 100 mg once daily or a matching placebo for 24 weeks. Randomization was stratified based on metformin use (on or not on metformin) and type of insulin (pre‐mixed vs intermediate‐/long‐acting) at screening. The primary end‐point was the change from baseline at week 24 in HbA1c.

Results

The addition of sitagliptin led to a significantly (P < 0.001) greater week 24 HbA1c reduction (0.7%) compared with the reduction (0.3%) with placebo. A significantly (P = 0.013) greater proportion of patients taking sitagliptin (16%) had an HbA1c of <7.0% at week 24 compared with placebo (8%). The addition of sitagliptin significantly (P < 0.001) reduced 2‐h post‐meal glucose by 26.5 mg/dL (1.5 mmol/L) relative to placebo. Reductions from baseline in fasting plasma glucose were observed in both the sitagliptin (14.4 mg/dL reduction) and placebo (10.7 mg/dL reduction) groups; the between‐group difference was not significant. A total of 64 (27.4%) patients taking sitagliptin and 51 (21.9%) taking placebo experienced adverse events of hypoglycemia (symptomatic or asymptomatic). Neither group had a significant change from baseline in bodyweight.

Conclusions

After 24 weeks, sitagliptin added to stable insulin therapy (±metformin) was generally well tolerated and improved glycemic control in Chinese patients with type 2 diabetes mellitus.

Insulin monotherapy compared with the addition of oral glucose-lowering agents to insulin for people with type 2 diabetes already on insulin therapy and inadequate glycaemic control

BACKGROUND

It is unclear whether people with type 2 diabetes mellitus on insulin monotherapy who do not achieve adequate glycaemic control should continue insulin as monotherapy or can benefit from adding oral glucose-lowering agents to the insulin therapy.

OBJECTIVES

To assess the effects of insulin monotherapy compared with the addition of oral glucose-lowering agents to insulin monotherapy for people with type 2 diabetes already on insulin therapy and inadequate glycaemic control.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and reference lists of articles. The date of the last search was November 2015 for all databases.

SELECTION CRITERIA

Randomised controlled clinical trials of at least two months' duration comparing insulin monotherapy with combinations of insulin with one or more oral glucose-lowering agent in people with type 2 diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias, extracted data and evaluated overall quality of the evidence using GRADE. We summarised data statistically if they were available, sufficiently similar and of sufficient quality. We performed statistical analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 37 trials with 40 treatment comparisons involving 3227 participants. The duration of the interventions ranged from 2 to 12 months for parallel trials and two to four months for cross-over trials.The majority of trials had an unclear risk of bias in several risk of bias domains. Fourteen trials showed a high risk of bias, mainly for performance and detection bias. Insulin monotherapy, including once-daily long-acting, once-daily intermediate-acting, twice-daily premixed insulin, and basal-bolus regimens (multiple injections), was compared to insulin in combination with sulphonylureas (17 comparisons: glibenclamide = 11, glipizide = 2, tolazamide = 2, gliclazide = 1, glimepiride = 1), metformin (11 comparisons), pioglitazone (four comparisons), alpha-glucosidase inhibitors (four comparisons: acarbose = 3, miglitol = 1), dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) (three comparisons: vildagliptin = 1, sitagliptin = 1, saxagliptin = 1) and the combination of metformin and glimepiride (one comparison). No trials assessed all-cause mortality, diabetes-related morbidity or health-related quality of life. Only one trial assessed patients' treatment satisfaction and showed no substantial differences between the addition of either glimepiride or metformin and glimepiride to insulin compared with insulin monotherapy.Insulin-sulphonylurea combination therapy (CT) compared with insulin monotherapy (IM) showed a MD in glycosylated haemoglobin A1c (HbA1c) of -1% (95% confidence interval (CI) -1.6 to -0.5); P < 0.01; 316 participants; 9 trials; low-quality evidence. Insulin-metformin CT compared with IM showed a MD in HbA1c of -0.9% (95% CI -1.2 to -0.5); P < 0.01; 698 participants; 9 trials; low-quality evidence. We could not pool the results of adding pioglitazone to insulin. Insulin combined with alpha-glucosidase inhibitors compared with IM showed a MD in HbA1c of -0.4% (95% CI -0.5 to -0.2); P < 0.01; 448 participants; 3 trials; low-quality evidence). Insulin combined with DPP-4 inhibitors compared with IM showed a MD in HbA1c of -0.4% (95% CI -0.5 to -0.4); P < 0.01; 265 participants; 2 trials; low quality evidence. In most trials the participants with CT needed less insulin, whereas insulin requirements increased or remained stable in participants with IM.We did not perform a meta-analysis for hypoglycaemic events because the included studies used different definitions.. In most trials the insulin-sulphonylurea combination resulted in a higher number of mild episodes of hypoglycaemia, compared to the IM group (range: 2.2 to 6.1 episodes per participant in CT versus 2.0 to 2.6 episodes per participant in IM; low-quality evidence). Pioglitazone CT also resulted in more mild to moderate hypoglycaemic episodes compared with IM (range 15 to 90 episodes versus 9 to 75 episodes, respectively; low-quality evidence. The trials that reported hypoglycaemic episodes in the other combinations found comparable numbers of mild to moderate hypoglycaemic events (low-quality evidence).The addition of sulphonylureas resulted in an additional weight gain of 0.4 kg to 1.9 kg versus -0.8 kg to 2.1 kg in the IM group (220 participants; 7 trials; low-quality evidence). Pioglitazone CT caused more weight gain compared to IM: MD 3.8 kg (95% CI 3.0 to 4.6); P < 0.01; 288 participants; 2 trials; low-quality evidence. Metformin CT was associated with weight loss: MD -2.1 kg (95% CI -3.2 to -1.1), P < 0.01; 615 participants; 7 trials; low-quality evidence). DPP-4 inhibitors CT showed weight gain of -0.7 to 1.3 kg versus 0.6 to 1.1 kg in the IM group (362 participants; 2 trials; low-quality evidence). Alpha-glucosidase CT compared to IM showed a MD of -0.5 kg (95% CI -1.2 to 0.3); P = 0.26; 241 participants; 2 trials; low-quality evidence.Users of metformin CT (range 7% to 67% versus 5% to 16%), and alpha-glucosidase inhibitors CT (14% to 75% versus 4% to 35%) experienced more gastro-intestinal adverse effects compared to participants on IM. Two trials reported a higher frequency of oedema with the use of pioglitazone CT (range: 16% to 18% versus 4% to 7% IM).

AUTHORS' CONCLUSIONS

The addition of all oral glucose-lowering agents in people with type 2 diabetes and inadequate glycaemic control who are on insulin therapy has positive effects on glycaemic control and insulin requirements. The addition of sulphonylureas results in more hypoglycaemic events. Additional weight gain can only be avoided by adding metformin to insulin. Other well-known adverse effects of oral glucose-lowering agents have to be taken into account when prescribing oral glucose-lowering agents in addition to insulin therapy.

PPARγ signaling and emerging opportunities for improved therapeutics

Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated nuclear receptor that regulates glucose and lipid metabolism, endothelial function and inflammation. Rosiglitazone (RGZ) and other thiazolidinedione (TZD) synthetic ligands of PPARγ are insulin sensitizers that have been used for the treatment of type 2 diabetes. However, undesirable side effects including weight gain, fluid retention, bone loss, congestive heart failure, and a possible increased risk of myocardial infarction and bladder cancer, have limited the use of TZDs. Therefore, there is a need to better understand PPARγ signaling and to develop safer and more effective PPARγ-directed therapeutics. In addition to PPARγ itself, many PPARγ ligands including TZDs bind to and activate G protein-coupled receptor 40 (GPR40), also known as free fatty acid receptor 1. GPR40 signaling activates stress kinase pathways that ultimately regulate downstream PPARγ responses. Recent studies in human endothelial cells have demonstrated that RGZ activation of GPR40 is essential to the optimal propagation of PPARγ genomic signaling. RGZ/GPR40/p38 MAPK signaling induces and activates PPARγ co-activator-1α, and recruits E1A binding protein p300 to the promoters of target genes, markedly enhancing PPARγ-dependent transcription. Therefore in endothelium, GPR40 and PPARγ function as an integrated signaling pathway. However, GPR40 can also activate ERK1/2, a proinflammatory kinase that directly phosphorylates and inactivates PPARγ. Thus the role of GPR40 in PPARγ signaling may have important implications for drug development. Ligands that strongly activate PPARγ, but do not bind to or activate GPR40 may be safer than currently approved PPARγ agonists. Alternatively, biased GPR40 agonists might be sought that activate both p38 MAPK and PPARγ, but not ERK1/2, avoiding its harmful effects on PPARγ signaling, insulin resistance and inflammation. Such next generation drugs might be useful in treating not only type 2 diabetes, but also diverse chronic and acute forms of vascular inflammation such as atherosclerosis and septic shock.

Continuation or discontinuation of pioglitazone when starting bedtime insulin in patients with poorly controlled type 2 diabetes in an inner-city population

OBJECTIVE

We studied the impact of continuing versus discontinuing pioglitazone on hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), and weight when starting bedtime insulin in patients with poor glycemic control.

METHODS

We retrospectively analyzed data from a 13-month randomized control trial on 77 patients with type 2 diabetes mellitus (DM), who despite maximum doses of three oral diabetes medications (metformin, sulfonylurea and pioglitazone) had HbA1C levels above 7.5%. Patients were randomized to either continuing or discontinuing pioglitazone in addition to starting and up-titrating bedtime insulin. HbA1C, FPG, and weight were assessed at baseline, 3months, 7months and 13months with the differences from baseline for the two groups compared at each of the three time points using the Wilcoxon rank sum test.

RESULTS

We found that HbA1c was significantly lower at the 7-month (p=0.01) and 13-month time points (p=0.036), and FPG was significantly lower at all three time points in the group continuing pioglitazone compared with those discontinuing pioglitazone. Continuing pioglitazone resulted in a greater increase in weight at the 3-month (p=0.002), 7-month (p=0.0001) and 13-month (p=0.00003) time points. Patients with the lowest HbA1c (<8.2%) at baseline were more likely to benefit from continuing pioglitazone than those with higher baseline HbA1c. Patients who started insulin and discontinued pioglitazone had similar HbA1c, FPG and weight at the three time points as at baseline, suggesting that pioglitazone and bedtime insulin has similar glycemic effect in this population.

CONCLUSIONS

We conclude that in patients with uncontrolled type 2 DM, continuing pioglitazone while concurrently starting bedtime insulin within a 13-month period led to a significant decrease in both HbA1c and FPG levels compared with those who did not receive pioglitazone; however weight increased during this period.

Improved glucose control with reduced hypoglycaemic risk when linagliptin is added to basal insulin in elderly patients with type 2 diabetes

AIM

To assess the efficacy, hypoglycaemia risk and other safety markers of linagliptin as an additional therapy in older patients (aged ≥70 years) inadequately controlled with basal insulin.

METHODS

A prespecified safety analysis from the linagliptin trials programme was carried out to explore the hypoglycaemia risk when linagliptin was added to background basal insulin therapy in elderly patients (≥70 years). To do this, two eligible, randomized, placebo-controlled, clinical trials (NCT00954447 and NCT01084005) of 24 and ≥52 weeks, respectively, were analysed.

RESULTS

A total of 247 elderly individuals [mean ± standard deviation (s.d.) age 74 ± 4 years, glycated haemoglobin (HbA1c) 8.2 ± 0.8%] on basal insulin (mean ± s.d. baseline dose 36 ± 25 IU/day) were identified. Alongside placebo-adjusted change in HbA1c with linagliptin of -0.77% [95% confidence interval (CI) -0.95 to 0.59; p < 0.0001] after 24 weeks, the hazard ratios (HRs) of both overall and confirmed hypoglycaemia [blood glucose ≤3.9 mmol/l (70 mg/dl)], were significantly lower with linagliptin than with placebo: HR 0.61 (95% CI 0.39-0.97) versus 0.59 (95% CI 0.37-0.94), respectively (both p < 0.05). Moreover, significantly less confirmed hypoglycaemia was present in linagliptin-treated patients with renal impairment [HR 0.45 (95% CI 0.27-0.76)], moderate hyperglycaemia [HbA1c 7.5 to <9.0%; HR 0.51 (95% CI 0.27-0.99)], lower fasting plasma glucose levels [<152 mg/dl; HR 0.49 (95% CI 0.28-0.86)] and those treated with higher insulin doses [insulin ≥35.6 IU/day; HR 0.46 (95% CI 0.23-0.91); p < 0.05 for all]. Severe hypoglycaemia was rare and the incidence was lower with linagliptin (0.8%) versus placebo (2.5%): HR 0.21 (95% CI 0.02-2.30).

CONCLUSIONS

Despite improvements in hyperglycaemia and no relevant on-trial insulin dose reductions, adding linagliptin to basal insulin appears to decrease hypoglycaemia risk. The biological basis of this phenomenon warrants further research but may involve counter-regulatory effects of incretin hormones.

Pharmacotherapy of type 2 diabetes mellitus: an update on drug-drug interactions

The incidence of type 2 diabetes mellitus is increasing rapidly, as are the associated co-morbidities. Consequently, it has become necessary for a diabetic patient to take multiple medications at the same time to delay progression of the disease. This can put patients at an increased risk of moderate to severe drug interactions, which may threaten patients' life or may deteriorate the quality of their life. Hence, managing drug-drug interactions is the cornerstone of anti-diabetic therapy. Most of the clinically important drug-drug interactions of anti-diabetic agents are related to their metabolic pathways, but drugs that compete for renal excretion or impair renal status can also play an important role. In this review, we have examined the clinical implications and underlying mechanisms of drugs that are likely to alter the pharmacologic response of or cause adverse events with antidiabetic drugs, and we have outlined safe and efficacious treatment modalities.

PPARγ partial agonist GQ-16 strongly represses a subset of genes in 3T3-L1 adipocytes

Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor gamma (PPARγ) agonists that improve insulin resistance but trigger side effects such as weight gain, edema, congestive heart failure and bone loss. GQ-16 is a PPARγ partial agonist that improves glucose tolerance and insulin sensitivity in mouse models of obesity and diabetes without inducing weight gain or edema. It is not clear whether GQ-16 acts as a partial agonist at all PPARγ target genes, or whether it displays gene-selective actions. To determine how GQ-16 influences PPARγ activity on a gene by gene basis, we compared effects of rosiglitazone (Rosi) and GQ-16 in mature 3T3-L1 adipocytes using microarray and qRT-PCR. Rosi changed expression of 1156 genes in 3T3-L1, but GQ-16 only changed 89 genes. GQ-16 generally showed weak effects upon Rosi induced genes, consistent with partial agonist actions, but a subset of modestly Rosi induced and strongly repressed genes displayed disproportionately strong GQ-16 responses. PPARγ partial agonists MLR24 and SR1664 also exhibit disproportionately strong effects on transcriptional repression. We conclude that GQ-16 displays a continuum of weak partial agonist effects but efficiently represses some negatively regulated PPARγ responsive genes. Strong repressive effects could contribute to physiologic actions of GQ-16.

A Randomized Clinical Trial to Evaluate the Efficacy and Safety of Co-Administration of Sitagliptin with Intensively Titrated Insulin Glargine

INTRODUCTION

The objective of this study was to assess the effect of sitagliptin on insulin dose in patients with inadequately controlled type 2 diabetes who titrate basal insulin to a target fasting glucose level after initiating sitagliptin.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled, 24-week clinical trial in which treatment with sitagliptin 100 mg/day or placebo was administered concurrently with insulin glargine titration, targeting a fasting glucose of 4.0-5.6 mmol/L (72-100 mg/dL). The trial randomized 660 patients with type 2 diabetes and inadequate glycemic control on insulin, with or without metformin (≥1500 mg/day) or sulfonylurea, for ≥10 weeks. Patients could remain on metformin but not sulfonylurea after randomization.

RESULTS

The increase from baseline in the daily dose of insulin was less in the sitagliptin group (N = 329) compared to placebo (N = 329) (between group difference = -4.7 IU [95% confidence interval [CI] -8.3, -1.2]; p = 0.009). Patients in the sitagliptin group had lower glycated hemoglobin (HbA1c) levels after 24 weeks (between-group difference of -0.4% [95% CI -0.6, -0.3; -4.9 mmol/mol (95% CI -6.6, -3.2)]; p < 0.001), and more patients in the sitagliptin group reached the HbA1c goal of <7.0% (53 mmol/mol), with a between-group difference of 17.3% (95% CI 10.4%, 24.1%; p < 0.001). Fewer patients in the sitagliptin group experienced an adverse event of hypoglycemia (between-group difference = -15.5%, p < 0.001).

CONCLUSION

Administration of sitagliptin prior to intensive titration of basal insulin glargine reduces the insulin dose requirement while providing superior glycemic control and less hypoglycemia, compared to an insulin-only regimen.

FUNDING

Merck & Co., Inc., Kenilworth, NJ, USA.

Heart failure in diabetes: effects of anti-hyperglycaemic drug therapy

Individuals with diabetes are not only at high risk of developing heart failure but are also at increased risk of dying from it. Fortunately, antiheart failure therapies such as angiotensin-converting-enzyme inhibitors, β blockers and mineralocorticoid-receptor antagonists work similarly well in individuals with diabetes as in individuals without the disease. Response to intensive glycaemic control and the various classes of antihyperglycaemic agent therapy is substantially less well understood. Insulin, for example, induces sodium retention and thiazolidinediones increase the risk of heart failure. The need for new glucose-lowering drugs to show cardiovascular safety has led to the unexpected finding of an increase in the risk of admission to hospital for heart failure in patients treated with the dipeptidylpeptidase-4 (DPP4) inhibitor, saxagliptin, compared with placebo. Here we review the relation between glycaemic control and heart failure risk, focusing on the state of knowledge for the various types of antihyperglycaemic drugs that are used at present.

Thiazolidinediones and Edema: Recent Advances in the Pathogenesis of Thiazolidinediones-Induced Renal Sodium Retention

Thiazolidinediones (TZDs) are one of the major classes of antidiabetic drugs that are used widely. TZDs improve insulin resistance by activating peroxisome proliferator-activated receptor gamma (PPARγ) and ameliorate diabetic and other nephropathies, at least, in experimental animals. However, TZDs have side effects, such as edema, congestive heart failure, and bone fracture, and may increase bladder cancer risk. Edema and heart failure, which both probably originate from renal sodium retention, are of great importance because these side effects make it difficult to continue the use of TZDs. However, the pathogenesis of edema remains a matter of controversy. Initially, upregulation of the epithelial sodium channel (ENaC) in the collecting ducts by TZDs was thought to be the primary cause of edema. However, the results of other studies do not support this view. Recent data suggest the involvement of transporters in the proximal tubule, such as sodium-bicarbonate cotransporter and sodium-proton exchanger. Other studies have suggested that sodium-potassium-chloride cotransporter 2 in the thick ascending limb of Henle and aquaporins are also possible targets for TZDs. This paper will discuss the recent advances in the pathogenesis of TZD-induced sodium reabsorption in the renal tubules and edema.

Insulin use and risk of diabetic macular edema in diabetes mellitus: a systemic review and meta-analysis of observational studies

BACKGROUND

Diabetes mellitus is a common and serious disorder. A search of the literature reveals no comprehensive quantitative assessment of the association between insulin use and incidence of diabetic macular edema. Therefore, we performed a meta-analysis of observational studies to evaluate the effect of insulin use on the risk of developing macular edema.

MATERIAL/METHODS

Comparative studies published until May 2014 were searched through a comprehensive search of the Medline, Embase, and the Cochrane Library electronic databases. A systematic review and quantitative analysis of comparative studies reporting the effect of insulin use on the incidence of macular edema was performed. All analyses were performed using the Review Manager (RevMan) v.5 (Nordic Cochrane Centre, Copenhagen, Denmark).

RESULTS

A total of 202 905 individuals were included in the present meta-analysis. In a random-effects meta-analysis, the use of insulin was found to be associated with increased risk of macular edema (RR, 3.416; 95% CI, 2.417-4.829; I2, 86.6%). Analysis that just included high-quality studies showed that insulin use increased the risk of macular edema (RR, 2.728; 95% CI, 1.881-3.955; I2=77.7%). In cohort studies (RR, 4.509; 95% CI, 3.100-6.559; I2, 77.7%) but not in case-control studies (RR, 1.455; 95% CI, 0.520 to 4.066; I2, 95.9%), increased incidence of macular edema was observed.

CONCLUSIONS

The results of this meta-analysis of observational studies demonstrate that insulin use is a risk factor for diabetic macular edema. However, available data are still sparse, and in-depth analyses of the assessed associations in the context of additional longitudinal studies are highly desirable to enable more precise estimates and a better understanding of the role of insulin use in incidence of diabetic macular edema.

Natural product agonists of peroxisome proliferator-activated receptor gamma (PPARγ): a review

Agonists of the nuclear receptor PPARγ are therapeutically used to combat hyperglycaemia associated with the metabolic syndrome and type 2 diabetes. In spite of being effective in normalization of blood glucose levels, the currently used PPARγ agonists from the thiazolidinedione type have serious side effects, making the discovery of novel ligands highly relevant. Natural products have proven historically to be a promising pool of structures for drug discovery, and a significant research effort has recently been undertaken to explore the PPARγ-activating potential of a wide range of natural products originating from traditionally used medicinal plants or dietary sources. The majority of identified compounds are selective PPARγ modulators (SPPARMs), transactivating the expression of PPARγ-dependent reporter genes as partial agonists. Those natural PPARγ ligands have different binding modes to the receptor in comparison to the full thiazolidinedione agonists, and on some occasions activate in addition PPARα (e.g. genistein, biochanin A, sargaquinoic acid, sargahydroquinoic acid, resveratrol, amorphastilbol) or the PPARγ-dimer partner retinoid X receptor (RXR; e.g. the neolignans magnolol and honokiol). A number of in vivo studies suggest that some of the natural product activators of PPARγ (e.g. honokiol, amorfrutin 1, amorfrutin B, amorphastilbol) improve metabolic parameters in diabetic animal models, partly with reduced side effects in comparison to full thiazolidinedione agonists. The bioactivity pattern as well as the dietary use of several of the identified active compounds and plant extracts warrants future research regarding their therapeutic potential and the possibility to modulate PPARγ activation by dietary interventions or food supplements.

Novel effects of rosiglitazone on SMAD2 and SMAD3 signaling in white adipose tissue of diabetic rats

OBJECTIVE

The effects of the proliferator-activated receptor gamma (PPARγ) agonist rosiglitazone (ROSI) on the transforming growth factor (TGF)-β/SMAD signaling pathway in white adipose tissue (WAT) of diabetic rats were assessed.

METHODS

Six-week-old, male ZDF rats were fed a chow diet with (ZDF ROSI) or without (ZDF chow) ROSI (diet, 100 mg/kg) for 6 weeks. Subcutaneous (scWAT) and retroperitoneal (rpWAT) adipose tissues were excised to quantify the protein content/phosphorylation.

RESULTS

ZDF ROSI animals showed enhanced glucose tolerance and mitochondrial protein content in both depots. The protein content of enzymes involved in fatty acid handling was increased in scWAT of ZDF ROSI animals. ZDF ROSI exhibited decreased phosphorylation of SMAD2 and SMAD3 exclusively in scWAT, along with increases in inhibitory SMAD7 and the E3 ubiquitin ligase SMURF2. In contrast, ROSI increased the protein content of SMAD4, TGF-β receptor I and II, and SMAD Anchor for Receptor Activation in scWAT.

CONCLUSIONS

For the first time, the fact that ROSI inhibits SMAD2 and SMAD3 signaling in a depot-specific manner in diabetic rats was demonstrated. In scWAT, ROSI reduced SMAD2 and SMAD3 phosphorylation, likely through the inhibitory actions of SMAD7 and SMURF2. Induction of proximal components of the SMAD pathway may constitute a feedback mechanism to counteract ROSI-induced lipid synthesis in scWAT.

Correlation of Circulating Acid-Labile Subunit Levels with Insulin Sensitivity and Serum LDL Cholesterol in Patients with Type 2 Diabetes: Findings from a Prospective Study with Rosiglitazone

Silencing of acid-labile subunit (ALS) improved glucose metabolism in animal models. The aim of this study is to evaluate the effects of rosiglitazone (RSG) on ALS levels in individuals with type 2 diabetes. A randomized, double-blind, placebo-controlled trial was conducted. Subjects with type 2 diabetes mellitus were randomly distributed to an RSG-treated (n = 30) or a placebo (n = 31) group. Patients were evaluated prior to treatment at baseline and at 12 and 24 weeks after treatment. At baseline, ALS levels were negatively associated with low-density lipoprotein cholesterol (LDLc) levels and homeostatic model assessment version 2 insulin sensitivity (HOMA2-%S). Over 24 weeks, there was a significantly greater reduction in ALS levels in the nonobese RSG-treated individuals than placebo-treated group. The effect of RSG on ALS was not significant in obese individuals. Fasting plasma glucose and hemoglobin A1c were reduced, but total cholesterol and LDLc were increased, in patients on RSG. Change in ALS levels predicted changes in total cholesterol and HOMA2-%S over time. This study suggested a BMI-dependent effect of RSG treatment on ALS levels. Reduction of ALS by RSG increases the risk of atherosclerosis in individuals with type 2 diabetes.

APOE*3Leiden.CETP transgenic mice as model for pharmaceutical treatment of the metabolic syndrome

AIMS

This study aimed to investigate systematically (i) the appropriate dietary conditions to induce the features of the MetS in APOE*3Leiden.humanCholesteryl Ester Transfer Protein (E3L.CETP) mice and (ii) whether the response of this model to different antidiabetic and hypolipidemic drugs is similar as in humans.

METHODS

Male obese, IR and dyslipidemic E3L.CETP mice were treated with antidiabetic drugs rosiglitazone, liraglutide or an experimental 11β-hydroxysteroid-dehydrogenase-1 (HSD-1) inhibitor, or with hypolipidemic drugs atorvastatin, fenofibrate or niacin for 4-6 weeks. The effects on bw, IR and plasma and liver lipids were assessed.

RESULTS

Rosiglitazone, liraglutide and HSD-1 inhibitor significantly decreased glucose and insulin levels or IR. Liraglutide and HSD-1 inhibitor also decreased bw. Atorvastatin, fenofibrate and niacin improved the dyslipidemia and fenofibrate and niacin increased high-density lipoprotein (HDL) cholesterol. In addition, hepatic triglycerides were significantly decreased by treatment with rosiglitazone and liraglutide, while hepatic cholesterol esters were significantly decreased by rosiglitazone and atorvastatin.

CONCLUSIONS

We conclude that the E3L.CETP mouse is a promising novel translational model to investigate the effects of new drugs, alone or in combination, that affect IR, diabetic dyslipidemia and non-alcoholic fatty liver disease (NAFLD).

Efficacy of pioglitazone on glycemic control and carotid intima-media thickness in type 2 diabetes patients with inadequate insulin therapy

Aims/Introduction:  The present study was designed to determine the effects of pioglitazone on glycemic control and atherosclerosis in patients with poorly controlled type 2 diabetes on insulin therapy.

Materials and Methods:  The study was a prospective, randomized controlled trial involving 48 patients with inadequately controlled type 2 diabetes treated with insulin. We assigned patients to oral pioglitazone titrated from 15–30 mg (n = 22) or no pioglitazone (n = 26), to be taken in addition to their glucose‐lowering drugs and other medications. Daily insulin doses and numbers were recorded during the study period.

Results:  The adjusted mean glycosylated hemoglobin (HbA_1c) values decreased significantly by 1.13 ± 1.50% and 0.55 ± 0.76% in the pioglitazone and control groups, respectively. Significant decrease of HbA_1c level was observed in the pioglitazone group compared with the control group (P < 0.05). The insulin dose lowered by 0.04 ± 0.10 units/kg/day in the pioglitazone group and increased by 0.03 ± 0.10 units/kg/day in the control group (P < 0.05). The number of insulin injections decreased by 0.1 ± 0.6 times/day in the pioglitazone group and increased by 0.2 ± 0.4 times/day in the control group (P < 0.05). The carotid intima‐media thickness estimated by B‐mode echography was carried out in both groups and decreased significantly at the end‐point only in the pioglitazone group, relative to the baseline.

Conclusions:  These findings show that pioglitazone is useful in improving glycemic control and preventing the progression of atherosclerosis in poorly‐controlled type 2 diabetics on insulin therapy. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00064.x, 2010)