Variations in tissue selectivity amongst insulin secretagogues: a systematic review

Current Position of Gliclazide and Sulfonylureas in the Contemporary Treatment Paradigm for Type 2 Diabetes: A Scoping Review

The increasing burden of type 2 diabetes (T2D), in relation to alarming rise in the prevalence; challenges in the diagnosis, prevention, and treatment; as well as the substantial impact of disease on longevity and quality of life, is a major concern in healthcare worldwide. Sulfonylureas (SUs) have been a cornerstone of T2D pharmacotherapy for over 60 years as oral antidiabetic drugs (OADs), while the newer generation SUs, such as gliclazide modified release (MR), are known to be associated with low risk of hypoglycemia in addition to the cardiovascular neutrality. This scoping review aimed to specifically address the current position of gliclazide MR among other SUs in the contemporary treatment paradigm for T2D and to provide a practical guidance document to assist clinicians in using gliclazide MR in real-life clinical practice. The main topics addressed in this paper include the role of early and sustained glycemic control and use of SUs in T2D management, the properties of gliclazide MR in relation to its effectiveness and safety, the use of gliclazide therapy in special populations, and the place of SUs as a class and gliclazide MR specifically in the current T2D treatment algorithm.

Identification of Novel Alkaloids from Portulaca oleracea L. and Characterization of Their Pharmacokinetics and GLP-1 Secretion-Promoting Activity in STC-1 Cells

Six new alkaloids (compounds 1-6) were isolated from Portulaca oleracea L. The compounds were triple pair (1 and 2, 3 and 4, and 5 and 6) enantiomers, with 1, 3, and 5 in the R-configuration and 2, 4, and 6 in the S-configuration, and all could bind to SUR1 according to molecular docking analysis. Treatment of STC-1 cells with each compound led to an influx of intracellular Ca2+, eventually leading to the secretion of glucagon-like peptide-1 (GLP-1), with compound 3 giving the highest secretion, resulting in 24.3 ± 7.03% more GLP-1 than nateglinide-treated cells, suggesting that these alkaloids may be able to reduce blood glucose based on their ability to stimulate the release of GLP-1. Furthermore, compound 3 also exhibited slightly faster absorption than nateglinide, as shown by pharmacokinetic analysis conducted in rats. Therefore, the results showed that some purslane alkaloids (such as compound 3) had good pharmacological activity in vivo and may have preventive and therapeutic effects on diabetes.

Sulfonylureas as second line therapy for type 2 diabetes among veterans: Results from a National Longitudinal Cohort Study

AIMS

To assess if switching to or adding sulfonylureas increases major adverse cardiovascular events (MACE) or severe hypoglycemia versus remaining on metformin alone.

MATERIALS AND METHODS

This was a retrospective, longitudinal cohort utilizing United States Veterans Health Administration and Medicare data. Veterans with type 2 diabetes on metformin monotherapy between 2004 and 2006 were identified. Follow-up occurred through 2016. Those treated with either metformin plus a second-generation sulfonylurea (N = 45,305) or converted from metformin to a second-generation sulfonylurea (N = 2813) were compared to those receiving metformin monotherapy (N = 65,550). Hazard ratios (HR) and 95%CI from longitudinal competing risk Cox models were used to measure the association between sulfonylureas and outcomes.

RESULTS

Switching to or adding a sulfonylurea to metformin was associated with 3 times the risk of severe hypoglycemia versus metformin monotherapy (HR:3.44, 95% CI: 3.06,3.85 and HR: 3.08, 95% CI: 2.77,3.42, respectively). Switching to or adding a sulfonylurea to metformin was associated with a 7-19% higher risk of MACE versus metformin monotherapy (HR: 1.07, 95% CI: 1.00,1.14 and HR: 1.19, 95% CI: 1.13,1.25, respectively).

CONCLUSIONS

Switching to and adding second-generation sulfonylureas was associated an increase in severe hypoglycemia and MACE versus remaining on metformin alone. In an era where guidelines recommend diabetes therapies based on compelling indications, safety outcomes should be a key consideration when selecting therapy.

Immunohistochemical, pharmacovigilance, and omics analyses reveal the involvement of ATP-sensitive K+ channel subunits in cancers: role in drug-disease interactions

Background: ATP-sensitive-K+ channels (KATP) are involved in diseases, but their role in cancer is poorly described. Pituitary macroadenoma has been observed in Cantu' syndrome (C.S.), which is associated with the gain-of-function mutations of the ABCC9 and KCNJ8 genes. We tested the role of the ABCC8/Sur1, ABCC9/Sur2A/B, KCNJ11/Kir6.2, and KCNJ8/Kir6.1 genes experimentally in a minoxidil-induced renal tumor in male rats and in the female canine breast cancer, a spontaneous animal model of disease, and in the pharmacovigilance and omics databases. Methods: We performed biopsies from renal tissues of male rats (N = 5) following a sub-chronic high dosing topical administration of minoxidil (0.777-77.7 mg/kg/day) and from breast tissues of female dogs for diagnosis (N = 23) that were analyzed by immunohistochemistry. Pharmacovigilance and omics data were extracted from EudraVigilance and omics databases, respectively. Results: An elevated immunohistochemical reactivity to Sur2A-mAb was detected in the cytosol of the Ki67+/G3 cells other than in the surface membrane in the minoxidil-induced renal tumor and the breast tumor samples. KCNJ11, KCNJ8, and ABCC9 genes are upregulated in cancers but ABCC8 is downregulated. The Kir6.2-Sur2A/B-channel opener minoxidil showed 23 case reports of breast cancer and one case of ovarian cancer in line with omics data reporting, respectively, and the negative and positive prognostic roles of the ABCC9 gene in these cancers. Sulfonylureas and glinides blocking the pancreatic Kir6.2-Sur1 subunits showed a higher risk for pancreatic cancer in line with the positive prognostic role of the ABCC8 gene but low risks for common cancers. Glibenclamide, repaglinide, and glimepiride show a lower cancer risk within the KATP channel blockers. The Kir6.2-Sur1 opener diazoxide shows no cancer reactions. Conclusion: An elevated expression of the Sur2A subunit was found in proliferating cells in two animal models of cancer. Immunohistochemistry/omics/pharmacovigilance data reveal the role of the Kir6.1/2-Sur2A/B subunits as a drug target in breast/renal cancers and in C.S.

The effect of interval training on adipokine plasmatic levels in rats with induced myocardial infarction

Context: Exercise has been demonstrated to reduce pro-inflammatory while boosting anti-inflammatory adipokines; yet research in relation to Myocardial infarction (MI) is limited.Objective: The aim of this study was to investigate the effect of an interval exercise-training programme on concentrations of Lipocalin-2 and Adiponectin plasmatic levels in rats with induced MI.Materials and methods: The experimental study design comprised of three groups, including: a control group, MI control group and MI training group that participated in an interval training protocol for six weeks.Results: There was a significant increase in Lipocalin-2 levels in the MI interval training group when compared to the other groups.Discussion and conclusion: Although interval training has beneficial effects on adiponectin, it also increases Lipocalin-2 concentrations. Because Lipocalin-2 significantly contributes to the pathogenesis of atherosclerosis and adverse cardiac conditions, our findings suggest that interval training might be a counterproductive strategy to improve MI-related cardiac damage.

Treatment of diabetes mellitus has borne much fruit in the prevention of cardiovascular disease

Cardiovascular (CV) disease is the most alarming complication of diabetes mellitus (DM), and a strategy aiming at cardiovascular event prevention in diabetes mellitus has long been debated. Large landmark clinical trials have shown cardiovascular benefits of intensive glycemic control as a ‘legacy effect’ in newly diagnosed type 2 diabetes mellitus. In contrast, we have learned that excessive intervention aimed at strong glycemic control could cause unexpected cardiovascular death in patients who are resistant to treatments against hyperglycemia. It has also been shown that the comprehensive multifactorial intervention for cardiovascular risk factors that was advocated in the current guideline provided substantial cardiovascular event reduction. The impact of classical antidiabetic agents launched before 1990s on cardiovascular events is controversial. Although there are many clinical or observational studies assessing the impact of those agents on cardiovascular events, the conclusions are inconsistent owing to variable patient backgrounds and concomitant antidiabetic agents among the studies. Moreover, most of them were not large‐scale, randomized, cardiovascular outcome trials. In contrast, GLP‐1RA (glucagon‐like peptide‐1 receptor agonist) and SGLT2 (sodium‐glucose cotransporter 2) inhibitors have demonstrated undeniable cardiovascular benefits in large‐scale, randomized, controlled trials. Whereas GLP‐1RAs decrease atherosclerotic disease, especially stroke, SGLT2 inhibitors mainly prevent heart failure. SGLT2 inhibitors are superior to GLP‐1RAs with respect to hard renal outcomes. Therefore, it can be said that drugs such as GLP‐1RAs and SGLT2 inhibitors that prevent cardiovascular events, in addition to their glucose‐lowering effect, are incredible novel tools that we have gained for use in diabetic treatment.

Association Between Specificity of Sulfonylureas to Cardiac Mitochondrial KATP Channels and the Risk of Major Adverse Cardiovascular Events in Type 2 Diabetes

OBJECTIVE

Previous studies have revealed an intraclass difference in major adverse cardiovascular events (MACE) among sulfonylureas. In vitro and ex vivo studies reported several sulfonylureas to exhibit high-affinity blockage of cardiac mitochondrial ATP-sensitive potassium (mitoKATP) channels and could interfere with ischemic preconditioning, the most important mechanism of self-cardiac protection. However, no studies have examined whether these varying binding affinities of sulfonylureas could account for their intraclass difference in MACE. We compared mitoKATP channel high-affinity versus low-affinity sulfonylureas regarding the MACE risk in real-world settings.

RESEARCH DESIGN AND METHODS

Using the Taiwan nationwide health care claims database, patients with type 2 diabetes initiating sulfonylurea monotherapy between 2007 and 2016 were included in the cohort study. A total of 33,727 new mitoKATP channel high-affinity (glyburide and glipizide) and low-affinity (gliclazide and glimepiride) sulfonylurea users, respectively, were identified after 1:1 propensity score matching. Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs) and 95% CI.

RESULTS

MitoKATP channel high-affinity sulfonylureas were associated with a significantly increased risk of three-point MACE (aHR 1.21 [95% CI 1.03-1.44]), ischemic stroke (aHR 1.23 [95% CI 1.02-1.50]), and cardiovascular death (aHR 2.61 [95% CI 1.31-5.20]), but not with that of myocardial infarction (aHR 1.04 [95% CI 0.75-1.46]). The duration-response analyses revealed the highest MACE risk to be within 90 days of therapy (aHR 4.67 [95% CI 3.61-6.06]).

CONCLUSIONS

Cardiac mitoKATP channel high-affinity sulfonylureas were associated with an increased MACE risk compared with low-affinity sulfonylureas in a nationwide population with diabetes.

The role of sulfonylureas in the treatment of type 2 diabetes

INTRODUCTION

Type 2 diabetes (T2D) is increasingly prevalent and associated with increased risk for cardiovascular and renal disease. After lifestyle modification, metformin is usually the first-line pharmacotherapy and sulfonylureas are traditionally added after metformin failure. However, with newer glucose lowering drugs that may have less risk of hypoglycemia or that may reduce cardiovascular and renal events, the position of sulfonylureas is being reevaluated.

AREAS COVERED

In this article, the authors review relevant publications related to the use of sulfonylureas.

EXPERT OPINION

Sulfonylureas are potent glucose lowering drugs. The risk of hypoglycemia varies with different drugs within the class and can be minimized by using the safer drugs, possibly in lower doses. Cardiovascular events do not appear to be increased with some of the newer generation drugs. The durability of glycemic control also appears comparable to other newer agents. Sulfonylureas are the preferred treatment for some types of monogenic diabetes and selection of T2D patients who may have greater benefit from sulfonylureas based on certain phenotypes and genotypes is likely to be refined further by precision medicine. Sulfonylureas are inexpensive and readily available everywhere and they are still the most frequently used second-line treatment for T2D in many parts of the world.

Changing the approach to type 2 diabetes treatment: A comparison of glucagon-like peptide-1 receptor agonists and sulphonylureas across the continuum of care

Despite the importance of individualised strategies for patients with type 2 diabetes mellitus (T2DM) and the availability of alternative treatments, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs), sulphonylureas are still widely used in practice. Clinical evidence shows that GLP-1 RAs may provide better and more durable glycaemic control than sulphonylureas, with lower risk of hypoglycaemia. Other reported benefits of GLP-1 RAs include weight loss rather than weight gain (as observed with sulphonylureas), blood pressure reduction and improvement in lipid profiles. In general, the main adverse events with GLP-1 RAs are gastrointestinal in nature. The respective modes of action of GLP-1 RAs and sulphonylureas contribute to differences in the durability of glycaemic control (related to effects on beta-cells) and effects on body weight. Moreover, the glucose-dependent mode of action of GLP-1 RAs, which favours a low incidence of hypoglycaemia, contrasts with the glucose-independent mode of action of sulphonylureas. Evidence from cardiovascular outcomes trials indicates a consistent finding of cardiovascular safety across the GLP-1 RAs and suggests a class benefit for the long-acting GLP-1 RAs in reducing three-point major adverse cardiovascular events, cardiovascular mortality and all-cause mortality. In contrast, potential concerns relating to an increased incidence of adverse cardiovascular events with sulphonylureas have yet to be fully resolved. Recent updates to management guidelines recommend that treatment selection for patients with T2DM should consider clinical trial evidence of cardiovascular safety. Available evidence suggests that this selection should give preference to GLP-1 RAs over sulphonylureas, especially for patients at high cardiovascular risk.

Glipizide Combined with ANP Suppresses Breast Cancer Growth and Metastasis by Inhibiting Angiogenesis through VEGF/VEGFR2 Signaling

BACKGROUND

Breast cancer is one of the most common cancers worldwide among women, and angiogenesis has an important effect on its growth and metastasis. Glipizide, which is a widely used drug for type 2 diabetes mellitus, has been reported to inhibit tumor growth and metastasis by upregulating the expression of natriuretic peptide receptor A (NPRA). Atrial natriuretic peptide (ANP), the receptor of NPRA, plays an important role in angiogenesis. The purpose of this study was to explore the effect of glipizide combined with ANP on breast cancer growth and metastasis.

METHODS

To investigate the effect of glipizide combined with ANP on breast cancer, glipizide, ANP or glipizide combined with ANP was intraperitoneally injected into MMTV-PyMT mice. To explore whether the anticancer efficacy of glipizide combined with ANP was correlated with angiogenesis, a tube formation assay was performed.

RESULTS

Glipizide combined with ANP was found to inhibit breast cancer growth and metastasis in MMTV-PyMT mice, which spontaneously develop breast cancer. Furthermore, the inhibitory effect of ANP combined with glipizide was better than that of glipizide alone. ANP combined with glipizide significantly inhibited tube formation of human umbilical vein endothelial cells (HUVECs) by suppressing vascular endothelial growth factor (VEGF)/VEGFR2 (vascular endothelial growth factor receptor 2) signaling.

CONCLUSIONS

These results demonstrate that glipizide combined with ANP has a greater potential than glipizide alone to be repurposed as effective agents for the treatment of breast cancer by targeting tumor-induced angiogenesis.

Zoledronic Acid as a Novel Dual Blocker of KIR6.1/2-SUR2 Subunits of ATP-Sensitive K+ Channels: Role in the Adverse Drug Reactions

Zoledronic acid (ZOL) is used as a bone-specific antiresorptive drug with antimyeloma effects. Adverse drug reactions (A.D.R.) are associated with ZOL-therapy, whose mechanics are unknown. ZOL is a nitrogen-containing molecule whose structure shows similarities with nucleotides, ligands of ATP-sensitive K⁺ (KATP) channels. We investigated the action of ZOL by performing in vitro patch-clamp experiments on native KATP channels in murine skeletal muscle fibers, bone cells, and recombinant subunits in cell lines, and by in silico docking the nucleotide site on KIR and SUR, as well as the glibenclamide site. ZOL fully inhibited the KATP currents recorded in excised macro-patches from Extensor digitorum longus (EDL) and Soleus (SOL) muscle fibers with an IC₅₀ of 1.2 ± 1.4 × 10⁻⁶ and 2.1 ± 3.7 × 10⁻¹⁰ M, respectively, and the KATP currents recorded in cell-attached patches from primary long bone cells with an IC₅₀ of 1.6 ± 2.8 × 10⁻¹⁰ M. ZOL fully inhibited a whole-cell KATP channel current of recombinant KIR6.1-SUR2B and KIR6.2-SUR2A subunits expressed in HEK293 cells with an IC₅₀ of 3.9 ± 2.7 × 10⁻¹⁰ M and 7.1 ± 3.1 × 10⁻⁶ M, respectively. The rank order of potency in inhibiting the KATP currents was: KIR6.1-SUR2B/SOL-KATP/osteoblast-KATP > KIR6.2-SUR2A/EDL-KATP >>> KIR6.2-SUR1 and KIR6.1-SUR1. Docking investigation revealed that the drug binds to the ADP/ATP sites on KIR6.1/2 and SUR2A/B and on the sulfonylureas site showing low binding energy <6 Kcal/mol for the KIR6.1/2-SUR2 subunits vs. the <4 Kcal/mol for the KIR6.2-SUR1. The IC₅₀ of ZOL to inhibit the KIR6.1/2-SUR2A/B channels were correlated with its musculoskeletal and cardiovascular risks. We first showed that ZOL blocks at subnanomolar concentration musculoskeletal KATP channels and cardiac and vascular KIR6.2/1-SUR2 channels.

Sulfonylureas in the Current Practice of Type 2 Diabetes Management: Are They All the Same? Consensus from the Gulf Cooperation Council (GCC) Countries Advisory Board on Sulfonylureas

Since their inception in the commercial market in the mid-twentieth century, sulfonylureas (SUs) have remained a therapeutic option in the management of type 2 diabetes (T2D). Despite their established glucose-lowering effects, there is no consensus among global experts and modern guidelines regarding the priority of SUs in relation to other therapeutic options, given the lack of evidence that SUs are associated with a low risk of macrovascular events and excess mortality. However, findings from recent trials and real-time observations have resolved this contentious issue somewhat, albeit to varying degrees. The present consensus discusses the role of SUs in contemporary diabetes management in the Gulf Cooperation Council (GCC) countries. Regional experts from these countries gathered virtually to formulate a consensus following presentations of topics relevant to SU therapy with an emphasis on gliclazide, including long-term efficacy, cost, end-organ benefits, and side effects, based on up-to-date evidence. The present narrative review reflects the conclusions of this assembly and provides a platform upon which future guidelines for the use of SUs in the GCC can be tailored.

Pleiotropic effects of anti-diabetic drugs: A comprehensive review

Diabetes mellitus characterized by hyperglycaemia presents an array of comorbidities such as cardiovascular and renal failure, dyslipidemia, and cognitive impairments. Populations above the age of 60 are in an urgent need of effective therapies to deal with the complications associated with diabetes mellitus. Widely used anti-diabetic drugs have good safety profiles and multiple reports indicate their pleiotropic effects in diabetic patients or models. This review has been written with the objective of identifying the widely-marketed anti-diabetic drugs which can be efficiently repurposed for the treatment of other diseases or disorders. It is an updated, comprehensive review, describing the protective role of various classes of anti-diabetic drugs in mitigating the macro and micro vascular complications of diabetes mellitus, and differentiating these drugs on the basis of their mode of action. Notably, metformin, the anti-diabetic drug most commonly explored for cancer therapy, has also exhibited some antimicrobial effects. Unlike class specific effects, few instances of drug specific effects in managing cardiovascular complications have also been reported. A major drawback is that the pleiotropic effects of anti-diabetic drugs have been mostly investigated only in diabetic patients. Thus, for effective repurposing, more clinical trials devoted to analyse the effects of anti-diabetic drugs in patients irrespective of their diabetic condition, are required.

Is Gliclazide Associated with a Lower Obesity-Related Cancer Risk Compared to Other Sulfonylureas? A Long-term Prospective Cohort Study

BACKGROUND

Gliclazide has been suspected to be associated with a lower obesity-related cancer risk; however, current evidence is limited by important methodologic shortcomings. This study aimed to evaluate whether gliclazide is preferred over other sulfonylureas regarding obesity-related cancer risk.

METHODS

In this prospective cohort study, an annual benchmarking database in Dutch primary care (Zwolle Outpatient Diabetes project Integrating Available CareZODIAC, 1998-2014) was linked to the Netherlands Cancer Registry and the Dutch Personal Record Database. Of the 71,648 patients with type 2 diabetes, we included 26,207 who used sulfonylureas and had no history of cancer or insulin use at baseline. Obesity-related cancer was defined using the latest definition of the World Cancer Research Fund. Cox regression analyses were used to estimate HRs, with both baseline sulfonylurea and cumulative exposure modeled and corrected for baseline covariates.

RESULTS

During follow-up for 167,692 person-years, there were 1,111 obesity-related cancer events. For males, the adjusted HRs [95% confidence interval (CI)] for baseline sulfonylurea compared with gliclazide were as follows: glibenclamide, 1.10 (0.92-2.69); glimepiride, 1.13 (0.68-1.84); and tolbutamide, 0.93 (0.59-1.48). For females, these were as follows: glibenclamide, 1.49 (0.72-3.13); glimepiride, 0.96 (0.59-1.54); and tolbutamide, 0.84 (0.54-1.28). The adjusted HRs (95% CI) for one more year of cumulative exposure compared with gliclazide were as follows: glibenclamide, 0.90 (0.71-1.14); glimepiride, 0.96 (0.87-1.06); and tolbutamide, 1.00 (0.92-1.09). For females, these were as follows: glibenclamide, 0.93 (0.77-1.13); glimepiride, 0.99 (0.90-1.10); and tolbutamide, 1.04 (0.96-1.13).

CONCLUSIONS

Obesity-related cancer risk was comparable between gliclazide and other sulfonylureas.

IMPACT

Gliclazide is not preferred over other sulfonylureas regarding obesity-related cancer risk.

ADVANCE in context: The benefits, risks and feasibility of providing intensive glycaemic control based on gliclazide modified release

In the last 3 decades, four large multicentre, randomized clinical trials of patients with type 2 diabetes (UKPDS, ADVANCE, ACCORD and VADT) have studied different approaches to achieving near normal glycaemic targets. Each was designed against a background of international and national guidelines recommending glycaemic targets of 6.5% or less to prevent diabetic complications. Collectively, these clinical trials provide the most robust evidence of the potential vascular benefits and risks of more versus less glucose control and provide critical insights into how therapies are used. In this review, the glucose-lowering approach used by the ADVANCE trial is considered and compared with those used by the other trials.

Effect of raw material variability of glipizide on the in vitro dissolution rate and in vivo bioavailability performance: The importance of particle size

The objective of this study was to understand the impact of active pharmaceutical ingredients (API) particle size on a re-developed generic product of glipizide and to improve its formulation so that it exhibits bioequivalent to that of the reference listed drug (RLD). Two commercial batches of APIs (API-1 and API-2) with the same polymorphism and one batch of home-made APIs (API-3) with super-small particle size were used in the present study. The in vitro dissolution profiles of the tested formulations were compared with the RLD in a series of dissolution media. Then, the impact of particle size on in vivo absorption was evaluated in Beagle dogs. Compared with the RLD, formulation A with larger API size showed slower dissolution in pH 6.0 and 7.4 medium, resulting bioinequivalent with the RLD. Conversely, formulation B with smaller API size demonstrated similar in vitro dissolution profiles with the RLD and thus exhibited bioequivalent in the present study. Furthermore, formulation C with super small particle size still exhibited identical oral absorption although rapid dissolution was observed in the tested condition. Herein, it indicated that 2-5 µm might be defined as the "inert size range" of glipizide for ensuring the bioequivalence with the RLD. The results in the present study might help to obtain a better understanding of the variability in raw materials for oral absorption, develop a bioequivalent product and thus post-market quality control.

Toxicity of Metformin and Hypoglycemic Therapies

Metformin along with other antidiabetic medications provide benefit to patients in the treatment of type 2 diabetes mellitus, but caution is advised in certain scenarios to avoid toxicity in kidney disease. Renal dosing, monitoring of kidney function, and evaluating the risk of developing serious side effects are warranted with some agents. The available literature with regard to incidence of adverse events and toxicity of hypoglycemic therapies is reviewed.

The right place for Sulphonylureas today

The place of Sulphonylurea based insulin secretagogues in the management of Type 2 diabetes appears as controversial today as it was fifty years ago. Newer therapies are associated with less hypoglycaemia and weight gain than Sulphonylureas but currently cost more and lack assurances which come with long-term exposure. Emergence of recent CVOT data for SGLT-2 inhibitors and GLP-1 receptor agonists is likely to influence therapeutic choices and guidance is now supportive of their earlier use in cases at high risk of cardiovascular disease. Meta-analyses of Sulphonylurea trials have failed to indicate a consistent effect (positive or negative) on cardiovascular disease or mortality, although are limited by the relative scarcity of studies directly reporting these outcomes. The CAROLINA trial is reassuring in demonstrating cardiovascular safety for the Sulphonylurea Glimepiride when compared directly with the DPP-4 inhibitor Linagliptin, suggesting either of these agents would be relatively safe second line options after Metformin in the majority of patients. This review provides a balanced assessment of available Sulphonylurea treatments in the context of current cardiovascular outcome trial data (CVOT) data and hopefully assists informed decision making about the place of these drugs in contemporary glucose lowering practice.

Reflections on the sulphonylurea story: A drug class at risk of extinction or a drug class worth reviving?

The role of sulphonylureas (SUs) in modern clinical practice poses ongoing clinical debate. With the advent of newer agents in diabetes management, there is an increasing shift away from the prescribing of SUs, but not necessarily to more effective agents. This review provides a different perspective on the debate, reflecting in depth upon the physiology of SUs, drawing on insights gained from monogenic diabetes to highlight the potential benefit of lower doses of SUs, and the probable benefit of gliclazide over most other, if not all SUs, in terms of sulphonylurea failure and cardiovascular outcomes.

Do sulphonylureas still have a place in clinical practice?

Sulphonylureas have been commercially available since the 1950s, but their use continues to be associated with controversy. Although adverse cardiovascular outcomes in some observational studies have raised concerns about sulphonylureas, findings from relatively recent, robust, and high-quality systematic reviews have indicated no increased risk of all-cause mortality associated with sulphonylureas compared with other active treatments. Results from large, multicentre, randomised controlled trials such as the UK Prospective Diabetes Study and ADVANCE have confirmed the microvascular benefits of sulphonylureas, a reduction in the incidence or worsening of nephropathy and retinopathy, and no increase in all-cause mortality, although whether these benefits were due to sulphonylurea therapy and not an overall glucose-lowering effect could not be confirmed. A comparison of sulphonylureas and pioglitazone in the TOSCA.IT trial also confirmed the efficacy and cardiovascular safety of sulphonylureas. Investigators of randomised controlled trials have reported an increased risk of hypoglycaemia and weight gain with sulphonylureas, but data from observational studies suggest that the incidence of severe hypoglycaemia is lower in people taking sulphonylurea than in people taking insulin, and weight gain with sulphonylureas has been relatively modest in large cohort studies. 80% of people with diabetes live in low-to-middle income countries, so the effectiveness, affordability, and safety of sulphonylureas are particularly important considerations when prescribing glucose-lowering therapy. Results of ongoing head-to-head studies with new drugs, such as the comparison of glimepiride with linagliptin in the CAROLINA study and the comparison of various therapies (including sulphonylureas) for glycaemic control in the GRADE study, will determine the place of sulphonylureas in glucose-lowering therapy algorithms for patients with type 2 diabetes.

Metformin combined with dipeptidyl peptidase-4 inhibitors or metformin combined with sulfonylureas in patients with type 2 diabetes: A real world analysis of the South Korean national cohort

AIMS

We explored the risks associated with metformin plus sulfonylurea (MET + SU) or MET plus a dipeptidyl peptidase-4 inhibitor (MET + DPP4i) for hypoglycemia, cardiovascular disease (CVD) events and all-cause mortality in type 2 diabetes (T2D) patients with comorbidities.

METHODS

This retrospective cohort study is based on the South Korean National Health Insurance Service-National Sample Cohort, enrolling T2D patients with one or more diabetes-related comorbidities who switched from monotherapy to MET + SU or MET + DPP4i between July 1, 2008 and December 31, 2013. The risk of hypoglycemia, CVD events and all-cause mortality was examined using Cox's proportional hazard modeling and propensity score matching.

RESULTS

Overall, 5693 patients with a mean of 2.6 comorbidities in addition to diabetes were included. Compared with MET + SU, MET + DPP4i treatment was associated with a lower risk of hypoglycemia, CVD events and all-cause mortality; adjusted HRs (95% CI), 0.39 (0.18-0.83), 0.72 (0.54-0.97), and 0.64 (0.39-1.05), respectively. Propensity score matching showed comparable results. In further subgroup analyses according to comorbidity type and number, MET + DPP4i was associated with less CVD events and all-cause mortality compared to MET + SU. This increased with more complex comorbid status.

CONCLUSIONS

In T2D patients with comorbidities, MET + DPP4i treatment is associated with lower risks of CVD events and all-cause mortality compared with MET + SU, independent of type or number of comorbidities. A more complex comorbid status further increases this effect.

Sulfonylureas as second line drugs in type 2 diabetes and the risk of cardiovascular and hypoglycaemic events: population based cohort study

OBJECTIVE

To assess whether adding or switching to sulfonylureas is associated with an increased risk of myocardial infarction, ischaemic stroke, cardiovascular death, all cause mortality, and severe hypoglycaemia, compared with remaining on metformin monotherapy in patients with type 2 diabetes.

DESIGN

Population based cohort study.

SETTING

General practices contributing data to the UK Clinical Practice Research Datalink.

PARTICIPANTS

Patients with type 2 diabetes initiating metformin monotherapy between 1998 and 2013.

MAIN OUTCOME MEASURES

Using the prevalent new-user cohort design we matched 1:1 patients adding or switching to sulfonylureas with those remaining on metformin monotherapy on high-dimensional propensity score, haemoglobin A1c, and number of previous metformin prescriptions. The two groups were compared using Cox proportional hazards models to estimate adjusted hazard ratios and 95% confidence intervals for the study outcomes.

RESULTS

Among 77 138 metformin initiators, 25 699 added or switched to sulfonylureas during the study period. During a mean follow-up of 1.1 years, sulfonylureas were associated with an increased risk of myocardial infarction (incidence rate 7.8 v 6.2 per 1000 person years, hazard ratio 1.26, 95% confidence interval 1.01 to 1.56), all cause mortality (27.3 v 21.5, 1.28, 1.15 to 1.44), and severe hypoglycaemia (5.5 v 0.7, 7.60, 4.64 to 12.44) compared with continuing metformin monotherapy. There was a trend towards increased risks of ischaemic stroke (6.7 v 5.5, 1.24, 0.99 to 1.56) and cardiovascular death (9.4 v 8.1, 1.18, 0.98 to 1.43). Compared with adding sulfonylureas, switching to sulfonylureas was associated with an increased risk of myocardial infarction (hazard ratio 1.51, 95% confidence interval, 1.03 to 2.24) and all-cause mortality (1.23, 1.00 to 1.50). No differences were observed for ischaemic stroke, cardiovascular death, or severe hypoglycaemia.

CONCLUSIONS

Sulfonylureas as second line drugs are associated with an increased risk of myocardial infarction, all cause mortality, and severe hypoglycaemia, compared with remaining on metformin monotherapy. Continuing metformin when introducing sulfonylureas appears to be safer than switching.

Binding of sulphonylureas to plasma proteins - A KATP channel perspective

Sulphonylurea drugs stimulate insulin secretion from pancreatic β-cells primarily by inhibiting ATP sensitive potassium (K_ATP) channels in the β-cell membrane. The effective sulphonylurea concentration at its site of action is significantly attenuated by binding to serum albumin, which makes it difficult to compare in vitro and in vivo data. We therefore measured the ability of gliclazide and glibenclamide to inhibit K_ATP channels and stimulate insulin secretion in the presence of serum albumin. We used this data, together with estimates of free drug concentrations from binding studies, to predict the extent of sulphonylurea inhibition of K_ATP channels at therapeutic concentrations in vivo. K_ATP currents from mouse pancreatic β-cells and Xenopus oocytes were measured using the patch-clamp technique. Gliclazide and glibenclamide binding to human plasma were determined in spiked plasma samples using an ultrafiltration-mass spectrometry approach. Bovine serum albumin (60g/l) produced a mild, non-significant reduction of gliclazide block of K_ATP currents in pancreatic β-cells and Xenopus oocytes. In contrast, glibenclamide inhibition of recombinant K_ATP channels was dramatically suppressed by albumin (predicted free drug concentration <0.1%). Insulin secretion was also reduced. Free concentrations of gliclazide and glibenclamide in the presence of human plasma measured in binding experiments were 15% and 0.05%, respectively. Our data suggest the free concentration of glibenclamide in plasma is too low to account for the drug’s therapeutic effect. In contrast, the free gliclazide concentration in plasma is high enough to close K_ATP channels and stimulate insulin secretion.

Pharmacotherapy of type 2 diabetes: An update

Type 2 diabetes (T2DM) is a leading cause of morbidity and mortality worldwide and a major economic burden. The prevalence of T2DM is rising, suggesting more effective prevention and treatment strategies are necessary. The aim of this narrative review is to summarize the pharmacologic treatment options available for patients with T2DM. Each therapeutic class is presented in detail, outlining medication effects, side effects, glycemic control, effect on weight, indications and contraindications, and use in selected populations (heart failure, renal insufficiency, obesity and the elderly). We also present representative cost for each antidiabetic category. Then, we provide an individualized guide for initiation and intensification of treatment and discuss the considerations and rationale for an individualized glycemic goal.

Pharmacologic Differences of Sulfonylureas and the Risk of Adverse Cardiovascular and Hypoglycemic Events

OBJECTIVE

Sulfonylureas have been associated with an increased risk of cardiovascular adverse events and hypoglycemia, but it is unclear if these risks vary with different agents. We assessed whether the risks of acute myocardial infarction, ischemic stroke, cardiovascular death, all-cause mortality, and severe hypoglycemia differ between sulfonylureas grouped according to pancreas specificity and duration of action.

RESEARCH DESIGN AND METHODS

Using the U.K. Clinical Practice Research Datalink, linked with the Hospital Episodes Statistics and the Office for National Statistics databases, we conducted a cohort study among patients with type 2 diabetes initiating monotherapy with sulfonylureas between 1998 and 2013. Adjusted hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards models, comparing use of pancreas-nonspecific, long-acting sulfonylureas (glyburide/glimepiride) to pancreas-specific, short-acting sulfonylureas (gliclazide/glipizide/tolbutamide).

RESULTS

The cohort included 17,604 sulfonylurea initiators (mean [SD] follow-up 1.2 [1.5] years). Compared with specific, short-acting sulfonylureas (15,741 initiators), nonspecific, long-acting sulfonylureas (1,863 initiators) were not associated with an increased risk of acute myocardial infarction (HR 0.86; CI 0.55-1.34), ischemic stroke (HR 0.92; CI 0.59-1.45), cardiovascular death (HR 1.01; CI 0.72-1.40), or all-cause mortality (HR 0.81; CI 0.66-1.003), but with an increased risk of severe hypoglycemia (HR 2.83; CI 1.64-4.88).

CONCLUSIONS

The nonspecific, long-acting sulfonylureas glyburide and glimepiride do not have an increased risk of cardiovascular adverse events compared with the specific, short-acting sulfonylureas gliclazide, glipizide, and tolbutamide. However, nonspecific, long-acting sulfonylureas glyburide and glimepiride have an increased risk of severe hypoglycemia.

The Antidiabetic Mechanisms of Polyphenols Related to Increased Glucagon-Like Peptide-1 (GLP1) and Insulin Signaling

Type-2 diabetes mellitus (T2DM) is an endocrine disease related to impaired/absent insulin signaling. Dietary habits can either promote or mitigate the onset and severity of T2DM. Diets rich in fruits and vegetables have been correlated with a decreased incidence of T2DM, apparently due to their high polyphenol content. Polyphenols are compounds of plant origin with several documented bioactivities related to health promotion. The present review describes the antidiabetic effects of polyphenols, specifically related to the secretion and effects of insulin and glucagon-like peptide 1 (GLP1), an enteric hormone that stimulates postprandial insulin secretion. The evidence suggests that polyphenols from various sources stimulate L-cells to secrete GLP1, increase its half-life by inhibiting dipeptidyl peptidase-4 (DPP4), stimulate β-cells to secrete insulin and stimulate the peripheral response to insulin, increasing the overall effects of the GLP1-insulin axis. The glucose-lowering potential of polyphenols has been evidenced in various acute and chronic models of healthy and diabetic organisms. Some polyphenols appear to exert their effects similarly to pharmaceutical antidiabetics; thus, rigorous clinical trials are needed to fully validate this claim. The broad diversity of polyphenols has not allowed for entirely describing their mechanisms of action, but the evidence advocates for their regular consumption.

The mechano-sensitivity of cardiac ATP-sensitive potassium channels is mediated by intrinsic MgATPase activity

Cardiac ATP-sensitive K⁺ (K_ATP) channel activity plays an important cardio-protective role in regulating excitability in response to metabolic stress. Evidence suggests that these channels are also mechano-sensitive and therefore may couple K_ATP channel activity to increased cardiac workloads. However, the molecular mechanism that couples membrane stretch to channel activity is not currently known. We hypothesized that membrane stretch may alter the intrinsic MgATPase activity of the cardiac K_ATP channel resulting in increased channel activation. The inside-out patch-clamp technique was used to record single-channel and macroscopic recombinant K_ATP channel activity in response to membrane stretch elicited by negative pipette pressure. We found that stretch activation requires the presence of the SUR subunit and that inhibition of MgATPase activity with either the non-hydrolysable ATP analog AMP-PNP or the ATPase inhibitor BeFx significantly reduced the stimulatory effect of stretch. We employed a point mutagenic approach to determine that a single residue (K1337) in the hairpin loop proximal to the major MgATPase catalytic site in the SUR2A subunit is responsible for the difference in mechano-sensitivity between SUR2A and SUR1 containing K_ATP channels. Moreover, using a double cysteine mutant substitution in the hairpin loop region revealed the importance of a key residue-residue interaction in this region that transduces membrane mechanical forces into K_ATP channel stimulation via increases in channel MgATPase activity. With respect to K_ATP channel pharmacology, glibenclamide, but not glicalizide or repaglinide, was able to completely inhibit K_ATP channel mechano-sensitivity. In summary, our results provide a highly plausible molecular mechanism by which mechanical membrane forces are rapidly converted in changes in K_ATP channel activity that have implications for our understanding of cardiac K_ATP channels in physiological or pathophysiological settings that involve increased workload.

Sulfonylureas and the Risks of Cardiovascular Events and Death: A Methodological Meta-Regression Analysis of the Observational Studies

Recent randomized trials have compared the newer antidiabetic agents to treatments involving sulfonylureas, drugs associated with increased cardiovascular risks and mortality in some observational studies with conflicting results. We reviewed the methodology of these observational studies by searching MEDLINE from inception to December 2015 for all studies of the association between sulfonylureas and cardiovascular events or mortality. Each study was appraised with respect to the comparator, the outcome, and study design-related sources of bias. A meta-regression analysis was used to evaluate heterogeneity. A total of 19 studies were identified, of which six had no major design-related biases. Sulfonylureas were associated with an increased risk of cardiovascular events and mortality in five of these studies (relative risks 1.16-1.55). Overall, the 19 studies resulted in 36 relative risks as some studies assessed multiple outcomes or comparators. Of the 36 analyses, metformin was the comparator in 27 (75%) and death was the outcome in 24 (67%). The relative risk was higher by 13% when the comparator was metformin, by 20% when death was the outcome, and by 7% when the studies had design-related biases. The lowest predicted relative risk was for studies with no major bias, comparator other than metformin, and cardiovascular outcome (1.06 [95% CI 0.92-1.23]), whereas the highest was for studies with bias, metformin comparator, and mortality outcome (1.53 [95% CI 1.43-1.65]). In summary, sulfonylureas were associated with an increased risk of cardiovascular events and mortality in the majority of studies with no major design-related biases. Among studies with important biases, the association varied significantly with respect to the comparator, the outcome, and the type of bias. With the introduction of new antidiabetic drugs, the use of appropriate design and analytical tools will provide their more accurate cardiovascular safety assessment in the real-world setting.

Molecular action of sulphonylureas on KATP channels: a real partnership between drugs and nucleotides

Sulphonylureas stimulate insulin secretion from pancreatic β-cells primarily by closing ATP-sensitive K⁺ channels in the β-cell plasma membrane. The mechanism of channel inhibition by these drugs is unusually complex. As direct inhibitors of channel activity, sulphonylureas act only as partial antagonists at therapeutic concentrations. However, they also exert an additional indirect inhibitory effect via modulation of nucleotide-dependent channel gating. In this review, we summarize current knowledge and recent advances in our understanding of the molecular mechanism of action of these drugs.

Hypoglycaemia when adding sulphonylurea to metformin: a systematic review and network meta-analysis

AIMS

The risk of hypoglycaemia may differ among sulphonylureas (SUs), but evidence from head-to-head comparisons is sparse. Performing a network meta-analysis to use indirect evidence from randomized controlled trials (RCTs), we compared the relative risk of hypoglycaemia with newer generation SUs when added to metformin.

METHODS

A systematic review identified RCTs lasting 12-52 weeks and evaluating SUs added to inadequate metformin monotherapy (≥1000 mg/day) in type 2 diabetes. Adding RCTs investigating the active comparators from the identified SU trials, we established a coherent network. Hypoglycaemia of any severity was the primary end point.

RESULTS

Thirteen trials of SUs and 14 of oral non-SU antihyperglycaemic agents (16 260 patients) were included. All reported hypoglycaemia only as adverse events. Producing comparable reductions in HbA_1C of -0.66 to -0.84% (-7 to -9 mmol/mol), the risk of hypoglycaemia was lowest with gliclazide compared to glipizide (OR 0.22, CrI: 0.05 to 0.96), glimepiride (OR 0.40, CrI: 0.13 to 1.27), and glibenclamide (OR 0.21, CrI: 0.03 to 1.48). A major limitation is varying definitions of hypoglycaemia across studies.

CONCLUSIONS

When added to metformin, gliclazide was associated with the lowest risk of hypoglycaemia between the newer generation SUs. Clinicians should consider the risk of hypoglycaemia agent-specific when selecting an SU agent.

Potential effects of current drug therapies on cognitive impairment in patients with type 2 diabetes

Type 2 diabetes mellitus is a complex metabolic disease that can cause serious damage to various organs. Among the best-known complications, an important role is played by cognitive impairment. Impairment of cognitive functioning has been reported both in type 1 and 2 diabetes mellitus. While this comorbidity has long been known, no major advances have been achieved in clinical research; it is clear that appropriate control of blood glucose levels represents the best current (although unsatisfactory) approach in the prevention of cognitive impairment. We have focused our attention on the possible effect on the brain of antidiabetic drugs, despite their effects on blood glucose levels, giving a brief rationale on the mechanisms (e.g. GLP-1, BDNF, ghrelin) that might be involved. Indeed, GLP-1 agonists are currently clinically studied in other neurodegenerative diseases (i.e. Parkinson's and Alzheimer's disease); furthermore, also other antidiabetic drugs have proven efficacy in preclinical studies. Overall, promising results are already available and finding new intervention strategies represents a current need in this field of research.

Sulphonylurea compared to DPP-4 inhibitors in combination with metformin carries increased risk of severe hypoglycemia, cardiovascular events, and all-cause mortality

AIMS

There are safety concerns related to sulphonylurea treatment. The objective of this nationwide study was to compare the risk of cardiovascular disease (CVD), all-cause mortality and severe hypoglycemia in patients with type 2 diabetes (T2D) starting second-line treatment with either metformin+sulphonylurea or metformin+dipeptidyl peptidase-4 inhibitor (DPP-4i).

METHODS

All patients with T2D in Sweden who initiated second-line treatment with metformin+sulphonylurea or metformin+DPP-4i during 2006-2013 (n=40,736 and 12,024, respectively) were identified in this nationwide study. The Swedish Prescribed Drug Register and the Cause of Death and National Patient Registers were used, and Cox survival models adjusted for age, sex, fragility, prior CVD, and CVD-preventing drugs were applied to estimate risks of events. Propensity score adjustments and matching methods were used to test the results.

RESULTS

Of 52,760 patients; 77% started metformin+SU and 23% metformin+DPP-4i. Crude incidences for severe hypoglycemia, CVD, and all-cause mortality in the SU cohort were 2.0, 19.6, and 24.6 per 1000 patient-years and in the DPP-4i cohort were 0.8, 7.6, and 14.9 per 1000 patient-years, respectively. Sulphonylurea compared with DPP4i was associated with higher risk of subsequent severe hypoglycemia, fatal and nonfatal CVD, and all-cause mortality; adjusted HR (95% CI): 2.07 (1.11-3.86); 1.17 (1.01-1.37); and 1.25 (1.02-1.54), respectively. Results were confirmed by additional propensity-adjusted and matched analyses. Among the SU drugs, glibenclamide had the highest risks.

CONCLUSIONS

Metformin+SU treatment was associated with an increased risk of subsequent severe hypoglycemia, cardiovascular events, and all-cause mortality compared with metformin+DPP4i. Results from randomized trials will be important to elucidate causal relationships.

DPP-4 inhibitors and cardiovascular disease in type 2 diabetes mellitus. Expectations, observations and perspectives

AIMS

Cardiovascular disease (CVD) is the greatest burden of type 2 diabetes mellitus (T2DM) in terms of morbility, mortality and costs for individuals and societies. Therefore, its prevention is a major goal in diabetes care. Optimal treatment of hyperglycemia is certainly instrumental to CVD prevention. Optimal treatment means both establishing the most appropriate glycemic target for the given individual and selecting the medication(s) with the most favourable benefit/safety ratio. CVD safety, if not a clear CVD benefit, is certainly required for all antidiabetic agents. Dipeptidyl-peptidase-4 (DPP-4) inhibitors are among the classes of antidiabetic agents most recently made available for diabetes care. A major question to be addressed is the effect of these compounds on CVD. Expectations were high for their mechanism of action, which targets also post-prandial glucose and minimize hypoglycemia risk, thereby providing a sort of global glucose control, and for some potentially beneficial extra-glycemic effects. This article reviews the existing literature on this issue.

DATA SYNTHESIS

Data published so far document that DPP-4 inhibitors have a wide spectrum of glycemic and extra-glycemic effects potentially reducing the risk of CVD as well as favourable effects on intermediate or surrogate CVD endpoints. These data heralded a better CVD outcome. Accordingly, pooling CVD safety data from phase 3 and 4 studies conducted with DPP-4 inhibitors suggested that their use might translate into a better CVD outcome. Data from three CVD outcome RCTs with alogliptin, saxagliptin and sitagliptin documented no harm but did not show any benefit on major CVD events. A modest but significant increased risk of hospitalization for heart failure was observed with saxagliptin and with alogliptin (only in subjects with no history of heart failure before randomization) but not with sitagliptin. A study currently in progress with linagliptin will provide further insights in the issue of CVD safety and benefit.

CONCLUSIONS

It should be considered that most alternative oral antidiabetic agents generally do not possess a better CVD risk profile than DPP-4 inhibitors and that some of them, indeed, should be used with caution because of potentially adverse effects on heart and vasculature. Overall, the selection of antidiabetic agent(s) with the most favourable CVD profile is mandatory but still challenging in diabetes care.

Comparative review of dipeptidyl peptidase-4 inhibitors and sulphonylureas

Type 2 diabetes (T2DM) is a progressive disease, and pharmacotherapy with a single agent does not generally provide durable glycaemic control over the long term. Sulphonylurea (SU) drugs have a history stretching back over 60 years, and have traditionally been the mainstay choice as second-line agents to be added to metformin once glycaemic control with metformin monotherapy deteriorates; however, they are associated with undesirable side effects, including increased hypoglycaemia risk and weight gain. Dipeptidyl peptidase (DPP)-4 inhibitors are, by comparison, more recent, with the first compound being launched in 2006, but the class now globally encompasses at least 11 different compounds. DPP-4 inhibitors improve glycaemic control with similar efficacy to SUs, but do not usually provoke hypoglycaemia or weight gain, are relatively free from adverse side effects, and have recently been shown not to increase cardiovascular risk in large prospective safety trials. Because of these factors, DPP-4 inhibitors have become an established therapy for T2DM and are increasingly being positioned earlier in treatment algorithms. The present article reviews these two classes of oral antidiabetic drugs (DPP-4 inhibitors and SUs), highlighting differences and similarities between members of the same class, as well as discussing the potential advantages and disadvantages of the two drug classes. While both classes have their merits, the choice of which to use depends on the characteristics of each individual patient; however, for the majority of patients, DPP-4 inhibitors are now the preferred choice.

Is gliclazide a sulfonylurea with difference? A review in 2016

Sulfonylureas (SUs) remain the most commonly prescribed drug after metformin in the treatment of type 2 diabetes (T2DM), despite the availability of several newer agents. The primary reason of SUs being most popular is their quick glycemic response, time-tested experience and least cost. Although SUs are one amongst the several other second line agents after metformin in all major guidelines, the new Dutch type 2 guidelines specifically advise gliclazide as the preferred second line drug instead of SUs as a class. The World Health Organization (WHO) has also included gliclazide in their Model List of Essential Medicines 2013 motivated by its safety data in elderly patients. Specifically advising gliclazide may have been based on emerging evidence suggesting cardiovascular neutrality of gliclazide over other SUs. This prompted us to do a literature review of gliclazide efficacy and safety data compared to other SUs as well as oral anti-diabetic drugs.

A spontaneous increase in intracellular Ca2+ in metaphase II human oocytes in vitro can be prevented by drugs targeting ATP-sensitive K+ channels

STUDY QUESTION

Could drugs targeting ATP-sensitive K(+) (K(ATP)) channels prevent any spontaneous increase in intracellular Ca(2+) that may occur in human metaphase II (MII) oocytes under in vitro conditions?

SUMMARY ANSWER

Pinacidil, a K(ATP) channel opener, and glibenclamide, a K(ATP) channel blocker, prevent a spontaneous increase in intracellular Ca(2+) in human MII oocytes.

WHAT IS KNOWN ALREADY

The quality of the oocyte and maintenance of this quality during in vitro processing in the assisted reproductive technology (ART) laboratory is of critical importance to successful embryo development and a healthy live birth. Maintenance of Ca(2+) homeostasis is crucial for cell wellbeing and increased intracellular Ca(2+) levels is a well-established indicator of cell stress.

STUDY DESIGN, SIZE, DURATION

Supernumerary human oocytes (n = 102) collected during IVF/ICSI treatment that failed to fertilize were used from October 2013 to July 2015. All experiments were performed on mature (MII) oocytes. Dynamics of intracellular Ca(2+) levels were monitored in oocytes in the following experimental groups: (i) Control, (ii) Dimethyl sulfoxide (DMSO; used to dissolve pinacidil, glibenclamide and 2,4-Dinitrophenol (DNP)), (iii) Pinacidil, (iv) Glibenclamide, (v) DNP: an inhibitor of oxidative phosphorylation, (vi) Pinacidil and DNP and (vii) Glibenclamide and DNP.

PARTICIPANTS/MATERIALS/SETTINGS/METHODS

Oocytes were collected under sedation as part of routine treatment at an assisted conception unit from healthy women (mean ± SD) age 34.1 ± 0.6 years, n = 41. Those surplus to clinical use were donated for research. Oocytes were loaded with Fluo-3 Ca(2+)-sensitive dye, and monitored by laser confocal microscopy for 2 h at 10 min intervals. Time between oocyte collection and start of Ca(2+) monitoring was 80.4 ± 2.1 h.

MAIN RESULTS AND THE ROLE OF CHANCE

Intracellular levels of Ca(2+) increased under in vitro conditions with no deliberate challenge, as shown by Fluo-3 fluorescence increasing from 61.0 ± 11.8 AU (AU = arbitrary units; n = 23) to 91.8 ± 14.0 AU (n = 19; P < 0.001) after 2 h of monitoring. Pinacidil (100 µM) inhibited this increase in Ca(2+) (85.3 ± 12.3 AU at the beginning of the experiment, 81.7 ± 11.0 AU at the end of the experiment; n = 13; P = 0.616). Glibenclamide (100 µM) also inhibited the increase in Ca(2+) (74.7 ± 10.6 AU at the beginning and 71.8 ± 10.9 AU at the end of the experiment; n = 13; P = 0.851. DNP (100 mM) induced an increase in intracellular Ca(2+) that was inhibited by glibenclamide (100 µM; n = 9) but not by pinacidil (100 µM; n = 5).

LIMITATIONS, REASONS FOR CAUTION

Owing to clinical and ethical considerations, it was not possible to monitor Ca(2+) in MII oocytes immediately after retrieval. MII oocytes were available for our experimentation only after unsuccessful IVF or ICSI, which was, on average, 80.4 ± 2.1 h (n = 102 oocytes) after the moment of retrieval. As the MII oocytes used here were those that were not successfully fertilized, it is possible that they may have been abnormal with impaired Ca(2+) homeostasis and, furthermore, the altered Ca(2+) homeostasis might have been associated solely with the protracted incubation.

WIDER IMPLICATIONS OF THE FINDINGS

These results show that maintenance of oocytes under in vitro conditions is associated with intracellular increase in Ca(2+), which can be counteracted by drugs targeting K(ATP) channels. As Ca(2+) homeostasis is crucial for contributing to a successful outcome of ART, these results suggest that K(ATP) channel openers and blockers should be tested as drugs for improving success rates of ART.

STUDY FUNDING/COMPETING INTERESTS

University of Dundee, MRC (MR/K013343/1, MR/012492/1), NHS Tayside. Funding NHS fellowship (Dr Sarah Martins da Silva), NHS Scotland. The authors declare no conflicts of interest.

Implementing an optimized glucose-lowering strategy with a novel once daily modified release gliclazide formulation

AIM

The 6-months titration profile of a new scored gliclazide modified release (MR) formulation (MR 60 mg) was explored in individuals with type 2 diabetes.

METHODS

This international study enrolled 7170 individuals, age ≥ 35 years with HbA1c ≥ 7.5% (59 mmol/mol) and not on insulin. Participants were started on 30-120 mg gliclazide MR 60 mg once daily as a first line (FIRST), add-on (ADD) or switch from a previous oral antihyperglycemic treatment strategy (SWITCH). Uptitration was capped at 120 mg.

RESULTS

Women comprised 58.5% of the cohort. Mean baseline age was 58.9 years, body mass index 30.1 kg/m(2) and diabetes duration 5.1 years. Mean baseline HbA1c for the FIRST (n=2023), ADD (n=3136) and SWITCH (n=1834) groups was 8.9% (74 mmol/mol), 8.8% (73 mmol/mol) and 8.8% (73 mmol/mol), respectively. Probability of reaching optimal dose at months 1, 2, 3 and 6 was 15%, 39%, 59% and 92%, respectively. Mean HbA1c changes from baseline to month 6 were FIRST: -1.98%, ADD: -1.74% and SWITCH: -1.61% (all p<0.01). Overall, 65.3% achieved HbA1c ≤ 7.0% (53 mmol/mol); average duration for achieving glucose control was 80.1 days. Mean weight loss ranged from -1.45 to -1.27 kg. Severe hypoglycemia was experienced by 0.06% of participants. Most (95.5%) indicated a greater likelihood of adherence with the gliclazide MR 60 mg regime relative to their previous therapy.

CONCLUSIONS

In this large, real world study, progressive uptitration with gliclazide MR 60 mg once daily appears to be efficacious and safe in individuals with suboptimal glycemic control at various stages of the diabetes continuum.

Effectiveness and Safety of Newer Antidiabetic Medications for Ramadan Fasting Diabetic Patients

Hypoglycemia is the most common side effects for most glucose-lowering therapies. It constitutes a serious risk that faces diabetic patients who fast during Ramadan (the 9th month in the Islamic calendar). New glucose-lowering classes like dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide 1 receptor agonist (GLP-1 RA), and sodium-glucose cotransporter-2 (SGLT-2) inhibitors are efficacious in controlling blood glucose level with less tendency to induce hypoglycemia and thus may constitute a good choice for diabetic patients during Ramadan. This study reviews the safety and efficacy of newer glucose-lowering therapies during Ramadan. This study was accomplished through a careful literature search about studies that assess the benefit and side effects of these new glucose-lowering therapies during Ramadan during September 2015. Vildagliptin, sitagliptin, liraglutide, exenatide, and dapagliflozin were the only studied glucose-lowering therapies. All of the studied newer glucose-lowering therapies except dapagliflozin were associated with reduced risk to induce hypoglycemia. Gastrointestinal upset was common with the usage of liraglutide while increased thirst sensation was common with dapagliflozin. In conclusion DPP-4 inhibitors such as vildagliptin and sitagliptin may form a suitable glucose-lowering therapy option for Ramadan fasting patients.

Effects of nateglinide and rosiglitazone on pancreatic alpha- and beta-cells, GLP-1 secretion and inflammatory markers in patients with type 2 diabetes: randomized crossover clinical study

BACKGROUND

To compare the effects of nateglinide and rosiglitazone on inflammatory markers, GLP-1 levels and metabolic profile in patients with type 2 diabetes (DM2).

METHODS

A prospective study was performed in 20 patients with DM2, mean age 51.82 ± 8.05 years, previously treated with dietary intervention. Participants were randomized into rosiglitazone (4-8 mg/day) or nateglinide (120 mg 3 times a day) therapy. After 4 months, the patients were crossed-over with 8 weeks washout period to the alternative treatment for an additional 4-month period on similar dosage schedule. The following variables were assessed before and after 4 months of each treatment period: (1) a test with a standardized 500 calories meal for 5 h including frequent measurements of glucose, insulin, glucagon, proinsulin, GLP-1, free fat acids (FFA), and triglycerides levels was obtained. The lipid profile and HbA1 levels were measured at fasting. (2) Haemostatic and inflammatory markers: platelet aggregation, fibrinogen, PAI-1 activity, C reactive protein (CRP), IL-6, TNF-α, leptin, sICAM and TGFβ levels.

RESULTS

Both therapy decreased blood glucose levels under the postprandial curve but neither affected glucagon and GLP-1 levels. Nateglinide was associated with higher insulin and pro-insulin secretion, but similar pro-insulin/insulin ratio when compared with rosiglitazone. Only rosiglitazone decreased Homa β, PAI-1 activity, CRP, fibrinogen, TGFβ, FFA and triglyceride levels.

CONCLUSIONS

Nateglinide and rosiglitazone were effective in improving glucose and lipid profile and β cell function, but rosiglitazone afforded a better anti-inflammatory effect. No drug restored alpha cell sensitivity or changed GLP-1 levels. Maintenance of haemostatic factors, inflammatory factors and glucagon levels can be related to the continuously worsening of cardiovascular function and glucose control observed in DM2.

Sulfonylureas and their use in clinical practice

Many anti-diabetic drugs with different mechanisms of action are now available for treatment of type 2 diabetes mellitus. Sulfonylureas have been extensively used for treatment of type 2 diabetes for nearly 50 years and, even in our times, are widely used for treatment of this devastating chronic illness. Here, we review some of the available data on sulfonylureas, evaluating their mechanism of action and their effects on glycemic control. We can conclude that sulfonylureas are still the most used anti-diabetic agents: maybe this is due to their lower cost, to the possibility of mono-dosing and to the presence of an association with metformin in the same tablet. However, sulfonylureas, especially the older ones, are linked to a greater prevalence of hypoglycemia, and cardiovascular risk; newer prolonged-release preparations of sulfonylureas are undoubtedly safer, mainly due to reducing hypoglycemia, and for this reason should be preferred.

Oral hypoglycemic agents and the heart failure conundrum: Lessons from and for outcome trials

AIM

Type 2 diabetes is not only an independent risk factor for cardiovascular (CV) disease but is also associated with a greater incidence of heart failure (HF). The aim of this review is to examine the effects of oral antidiabetic drugs on CV disease and HF.

DATA SYNTHESIS

Trials of anti-diabetic agents are now designed to assess CV safety, but frequently HF is not included as a primary endpoint. However, HF in patients with diabetes is more frequent than other CV events and seems to be underestimated. A burning question is therefore if the most used trial design to monitor CV safety, i.e. non-inferiority, allows clinical translation of trial findings. Available data further suggest that the CV effects of anti-diabetic drugs may be rather class-specific and are only partly due to their glucose-lowering actions. Metformin, recommended as first line in most guidelines, shows positive CV effects while other classes like thiazolidinediones may precipitate HF. Experimental results on the relatively novel dipeptidyl peptidase IV (DPP IV) inhibitors imply CV protective effects, but the non-inferiority trials published to date show an overall neutral CV outcome and a potential increase in HF by saxagliptin. However, results on sitagliptin of the recently released TECOS indicate that HF is not a class-dependent effect of DPP IV inhibitors.

CONCLUSION

Further basic research and long-term outcome studies to clarify the effects of antidiabetic agents on CV and HF are required so that we can select the optimal antidiabetic therapy for our patients.

The effect of gliquidone on KATP channels in pancreatic β-cells, cardiomyocytes, and vascular smooth muscle cells

AIMS

Sulfonylurea drugs exert an insulinotropic effect through ATP-sensitive potassium (KATP) channel inhibition in pancreatic islet cells. These channels are also expressed in cardiomyocytes and vascular smooth muscle cells (VSMCs), suggesting potential for adverse cardiovascular effects. We evaluated the effects of Gliquidone (Glq) on sulfonylurea receptors in HIT-T15 cells (SUR1), cardiomyocytes (SUR2A), and VSMCs (SUR2B).

METHODS

The concentration-dependent effects of Glq (0.001-500 μM) on KATP channels were assessed using whole-cell patch clamp in HIT-T15 cells, rat cardiomyocytes, and VSMCs. Parallel studies using Glibenclamide (Glb) (0.001-10 μM) and Gliclazide (Glc) (0.01-500 μM)were conducted as controls.

RESULTS

In HIT-T15 cells, Glb exhibited the lowest IC50 (0.03 μM), as compared to Glq (0.45μM) and Glc (1.21μM). However, Glq had higher IC50 in cardiomyoctes and VSMCs, as compared to Glb (119.1 vs. 0.01 and 149.7 vs. 0.09 μM, respectively), suggesting that Glq is more selective to β-cells than Glb. Thus, Glq may have fewer side effects in cardiomyoctes and VSMCs.

CONCLUSIONS

Glq is a highly selective SUR secretagogue with moderate affinity to β-cells, but low affinity to cardiomyocytes and VSMCs. Our data also reveal the non-selective nature of Glb, as evidenced by high binding affinity to KATP channels in all the three cell types examined.

Sulfonylureas suppress the stimulatory action of Mg-nucleotides on Kir6.2/SUR1 but not Kir6.2/SUR2A KATP channels: a mechanistic study

Sulfonylureas suppress the stimulatory effect of Mg-nucleotides on recombinant β-cell (Kir6.2/SUR1) but not cardiac (Kir6.2/SUR2A) K_ATP channels.

Sulfonylureas, which stimulate insulin secretion from pancreatic β-cells, are widely used to treat both type 2 diabetes and neonatal diabetes. These drugs mediate their effects by binding to the sulfonylurea receptor subunit (SUR) of the ATP-sensitive K⁺ (K_ATP) channel and inducing channel closure. The mechanism of channel inhibition is unusually complex. First, sulfonylureas act as partial antagonists of channel activity, and second, their effect is modulated by MgADP. We analyzed the molecular basis of the interactions between the sulfonylurea gliclazide and Mg-nucleotides on β-cell and cardiac types of K_ATP channel (Kir6.2/SUR1 and Kir6.2/SUR2A, respectively) heterologously expressed in Xenopus laevis oocytes. The SUR2A-Y1206S mutation was used to confer gliclazide sensitivity on SUR2A. We found that both MgATP and MgADP increased gliclazide inhibition of Kir6.2/SUR1 channels and reduced inhibition of Kir6.2/SUR2A-Y1206S. The latter effect can be attributed to stabilization of the cardiac channel open state by Mg-nucleotides. Using a Kir6.2 mutation that renders the K_ATP channel insensitive to nucleotide inhibition (Kir6.2-G334D), we showed that gliclazide abolishes the stimulatory effects of MgADP and MgATP on β-cell K_ATP channels. Detailed analysis suggests that the drug both reduces nucleotide binding to SUR1 and impairs the efficacy with which nucleotide binding is translated into pore opening. Mutation of one (or both) of the Walker A lysines in the catalytic site of the nucleotide-binding domains of SUR1 may have a similar effect to gliclazide on MgADP binding and transduction, but it does not appear to impair MgATP binding. Our results have implications for the therapeutic use of sulfonylureas.

Cardiovascular safety of sulphonylureas: over 40 years of continuous controversy without an answer

More than 40 years after publication of the University Group Diabetes Program trial, the cardiovascular safety of sulphonylureas is still contentious. Although several hypotheses linking sulphonylureas to adverse cardiovascular effects exist, none provide conclusive evidence. Adding to the controversy, current clinical trials and observational studies provide inconsistent, and sometimes conflicting, evidence for the cardiovascular effects of sulphonylureas. Overall, observational evidence suggests that an increased risk of adverse cardiovascular outcomes is associated with sulphonylureas; however, these data may be subject to residual confounding and bias. Although evidence from randomized controlled trials has suggested a neutral effect, the majority of these studies were not specifically designed to assess the effect of sulphonylureas on adverse cardiovascular event risk. Current ongoing large clinical trials may provide some clarity on the cardiovascular safety of sulphonylureas, but the results are not expected for several years. With the continued uncertainties concerning the cardiovascular safety of all antidiabetic drugs, a clear answer with regard to sulphonylureas is warranted. The objectives of the present article were to provide an overview of the controversy surrounding sulphonylurea-related cardiovascular effects, to discuss the limitations of the current literature, and to provide recommendations for future studies aiming to elucidate the true relationship between sulphonylureas and adverse cardiovascular effects in people with type 2 diabetes.

Comparative cardiovascular safety of insulin secretagogues following hospitalization for ischemic heart disease among type 2 diabetes patients: a cohort study

AIM

To evaluate the association between insulin secretagogues and adverse cardiovascular sequelae in type 2 diabetes patients hospitalized for ischemic heart disease (IHD).

METHODS

Administrative health records from Alberta, Canada between 1998 and 2010 were used to identify 2,254 gliclazide, 3,289 glyburide and 740 repaglinide users prior to an IHD-related hospitalization. Multivariable Cox regression models were used to compare the 30-day risk of a composite outcome of all-cause mortality or new onset of atrial fibrillation, stroke, heart failure or myocardial infarction according to insulin secretagogue use.

RESULTS

Mean (SD) age was 76.1 (6.9) years, and 60.7% were men. The composite outcome occurred in 322 (30.2%) gliclazide users, 455 (28.1%) glyburide users and 81 (23.4%) repaglinide users within 30 days of IHD hospitalization. There were no differences in risk for glyburide use (adjusted hazard ratio [aHR] 0.91; 95% confidence interval [CI] 0.78-1.05) or repaglinide use (aHR 0.80; 95% CI 0.63-1.03) compared to gliclazide. Similar results were observed in analyses for each element of the composite outcome.

CONCLUSIONS

In older patients with type 2 diabetes hospitalized for IHD, prior use of gliclazide, glyburide, or repaglinide appears to be associated with a similar risk of adverse cardiovascular sequelae.

Dipeptidyl peptidase-4 inhibitors can minimize the hypoglycaemic burden and enhance safety in elderly people with diabetes

The prevalence of type 2 diabetes mellitus (T2DM) among elderly people is increasing. Often associated with disabilities/comorbidities, T2DM lowers the chances of successful aging and is independently associated with frailty and an increased risk of hypoglycaemia, which can be further exacerbated by antihyperglycaemic treatment. From this perspective, the clinical management of T2DM in the elderly is challenging and requires individualization of optimum glycaemic targets depending on comorbidities, cognitive functioning and ability to recognize and self-manage the disease. The lack of solid evidence-based medicine supporting treatment guidelines for older people with diabetes further complicates the matter. Several classes of medicine for the treatment of T2DM are currently available and different drug combinations are often required to achieve individualized glycaemic goals. Many of these drugs, however, carry disadvantages such as the propensity to cause weight gain or hypoglycaemia. Dipeptidyl peptidase-4 (DPP-4) inhibitors, a recent addition to the pharmacological armamentarium, have become widely accepted in clinical practice because of their efficacy, low risk of hypoglycaemia, neutral effect on body weight, and apparently greater safety in patients with kidney failure. Although more information is needed to reach definitive conclusions, growing evidence suggests that DPP-4 inhibitors may become a valuable component in the pharmacological management of elderly people with T2DM. The present review aims to delineate the potential advantages of this pharmacological approach in the treatment of elderly people with T2DM.