The role of sulphonylureas in the management of type 2 diabetes mellitus

Efficacy and safety of liraglutide compared to sulphonylurea during Ramadan in patients with type 2 diabetes (LIRA-Ramadan): a randomized trial

AIMS

Compare effects of liraglutide 1.8 mg and sulphonylurea, both combined with metformin, on glycaemic control in patients with type 2 diabetes (T2D) fasting during Ramadan.

MATERIALS AND METHODS

In this up to 33-week, open-label, active-controlled, parallel-group trial, adults [glycated haemoglobin (HbA1c) 7%-10% (53-86 mmol/mol); body mass index ≥20 kg/m(2) ; intent to fast] were randomized (1:1) ≥10 weeks before Ramadan to either switch to once-daily liraglutide (final dose 1.8 mg) or continue pre-trial sulphonylurea at maximum tolerated dose, both with metformin.

PRIMARY ENDPOINT

change in fructosamine, a validated marker of short-term glycaemic control, during Ramadan.

RESULTS

Similar reductions in fructosamine levels were observed for both groups during Ramadan [liraglutide (-12.8 µmol/L); sulphonylurea (-16.4 µmol/L); estimated treatment difference (ETD) 3.51 µmol/L (95% CI: -5.26; 12.28); p = 0.43], despite lower fructosamine levels in the liraglutide group at start of Ramadan. Fewer documented symptomatic hypoglycaemic episodes were reported in liraglutide-treated (2%, three subjects) versus sulphonylurea-treated patients (11%, 18 subjects). No severe hypoglycaemic episodes were reported by either group. Body weight decreased more during Ramadan with liraglutide (ETD: -0.54 kg; 95% CI: -0.94;-0.14; p = 0.0091). The proportion of patients reporting adverse events was similar between groups. Liraglutide led to greater HbA1c reduction [ETD: -0.59% (-6.40 mmol/mol), 95% CI: -0.79; -0.38%; -8.63; -4.17 mmol/mol; p < 0.0001].

CONCLUSIONS

Despite lower fructosamine levels and body weight at the beginning of Ramadan, use of liraglutide showed similar glycaemic improvements, fewer hypoglycaemic episodes and greater body weight reduction compared with sulphonylurea. LIRA-Ramadan provides evidence for liraglutide being safe and efficacious for management of T2D during Ramadan fasting.

Pharmacology and therapeutic implications of current drugs for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a global epidemic that poses a major challenge to health-care systems. Improving metabolic control to approach normal glycaemia (where practical) greatly benefits long-term prognoses and justifies early, effective, sustained and safety-conscious intervention. Improvements in the understanding of the complex pathogenesis of T2DM have underpinned the development of glucose-lowering therapies with complementary mechanisms of action, which have expanded treatment options and facilitated individualized management strategies. Over the past decade, several new classes of glucose-lowering agents have been licensed, including glucagon-like peptide 1 receptor (GLP-1R) agonists, dipeptidyl peptidase 4 (DPP-4) inhibitors and sodium/glucose cotransporter 2 (SGLT2) inhibitors. These agents can be used individually or in combination with well-established treatments such as biguanides, sulfonylureas and thiazolidinediones. Although novel agents have potential advantages including low risk of hypoglycaemia and help with weight control, long-term safety has yet to be established. In this Review, we assess the pharmacokinetics, pharmacodynamics and safety profiles, including cardiovascular safety, of currently available therapies for management of hyperglycaemia in patients with T2DM within the context of disease pathogenesis and natural history. In addition, we briefly describe treatment algorithms for patients with T2DM and lessons from present therapies to inform the development of future therapies.

Review: Sulphonylureas and cardiovascular risk: facts and controversies

Cardiovascular complications are the principal cause of death in type 2 diabetes. The importance of glycaemic control in preventing cardiovascular complications has been demonstrated. However, some oral antidiabetic agents and especially some sulphonylureas (SU) have been accused of having a deleterious effect on cardiovascular risk. A retrospective analysis of the administrative database of Saskatchewan Health for 5,795 subjects, identified by their first-ever dispensation for an oral antidiabetic agent, suggests that a higher exposure to SUs was associated with increased mortality. Nevertheless, the effects of SUs on cardiac ATP-sensitive potassium channels in experimental studies vary between agents and studies, so that the clinical relevance of this phenomenon is unclear. Moreover, 11 years of follow-up of patients randomised to glibenclamide or chlorpropamide in the United Kingdom Prospective Diabetes Study demonstrated no adverse effects on a range of cardiovascular end points. Despite SU structural differences and differences in binding to cardiac SU receptors, the clinical evidence base does not support the selection of one sulphonylurea over another on the basis of ischaemic preconditioning, possibly because ischaemic preconditioning may be blunted or absent in diabetes. The main objective remains the prevention or delay of diabetic complications through improvement of glycaemic control together with other cardiovascular risk factors.

Natural Phyto-Bioactive Compounds for the Treatment of Type 2 Diabetes: Inflammation as a Target

Diabetes is a metabolic, endocrine disorder which is characterized by hyperglycemia and glucose intolerance due to insulin resistance. Extensive research has confirmed that inflammation is closely involved in the pathogenesis of diabetes and its complications. Patients with diabetes display typical features of an inflammatory process characterized by the presence of cytokines, immune cell infiltration, impaired function and tissue destruction. Numerous anti-diabetic drugs are often prescribed to diabetic patients, to reduce the risk of diabetes through modulation of inflammation. However, those anti-diabetic drugs are often not successful as a result of side effects; therefore, researchers are searching for efficient natural therapeutic targets with less or no side effects. Natural products' derived bioactive molecules have been proven to improve insulin resistance and associated complications through suppression of inflammatory signaling pathways. In this review article, we described the extraction, isolation and identification of bioactive compounds and its molecular mechanisms in the prevention of diabetes associated complications.

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.

Computational Analysis of Single Nucleotide Polymorphisms Associated with Altered Drug Responsiveness in Type 2 Diabetes

Type 2 diabetes (T2D) is one of the most frequent mortality causes in western countries, with rapidly increasing prevalence. Anti-diabetic drugs are the first therapeutic approach, although many patients develop drug resistance. Most drug responsiveness variability can be explained by genetic causes. Inter-individual variability is principally due to single nucleotide polymorphisms, and differential drug responsiveness has been correlated to alteration in genes involved in drug metabolism (CYP2C9) or insulin signaling (IRS1, ABCC8, KCNJ11 and PPARG). However, most genome-wide association studies did not provide clues about the contribution of DNA variations to impaired drug responsiveness. Thus, characterizing T2D drug responsiveness variants is needed to guide clinicians toward tailored therapeutic approaches. Here, we extensively investigated polymorphisms associated with altered drug response in T2D, predicting their effects in silico. Combining different computational approaches, we focused on the expression pattern of genes correlated to drug resistance and inferred evolutionary conservation of polymorphic residues, computationally predicting the biochemical properties of polymorphic proteins. Using RNA-Sequencing followed by targeted validation, we identified and experimentally confirmed that two nucleotide variations in the CAPN10 gene—currently annotated as intronic—fall within two new transcripts in this locus. Additionally, we found that a Single Nucleotide Polymorphism (SNP), currently reported as intergenic, maps to the intron of a new transcript, harboring CAPN10 and GPR35 genes, which undergoes non-sense mediated decay. Finally, we analyzed variants that fall into non-coding regulatory regions of yet underestimated functional significance, predicting that some of them can potentially affect gene expression and/or post-transcriptional regulation of mRNAs affecting the splicing.

Association of KCNQ1 polymorphisms with gliclazide efficacy in Chinese type 2 diabetic patients

OBJECTIVES

To investigate the effects of KCNQ1 polymorphisms on the efficacy of gliclazide in type 2 diabetic patients.

MATERIALS AND METHODS

A total of 443 newly diagnosed type 2 diabetic patients were included in this study. After enrollment, patients went on an 8-week gliclazide monotherapy. Fasting plasma glucose (FPG) was measured before and after the treatment. Life-style information was collected by weekly follow-up. Genotyping of the two single-nucleotide polymorphisms was performed using the single base primer extension method. T-test, one-way analysis of variance, and Pearson χ-test were used to evaluate the effects of rs2237892 and rs2237897 on the FPG reduction and treatment success rate.

RESULTS

After 8 weeks of gliclazide therapy, the FPG decreased significantly from 10.9±2.8 to 7.4±2.2 mmol/l (P<0.001). Compared with the CC genotype, patients with CT or TT genotypes of rs2237897 achieved greater reduction in FPG (3.9±2.6 vs. 3.2±2.4 mmol/l, P=0.003; 33.9±19.0 vs. 27.7±17.4%, P<0.001) and a higher rate of treatment success (74.1 vs. 65.2%, P=0.042 for criterion 1; 61.1 vs. 44.5%, P<0.001 for criterion 2, respectively), whereas no significant difference was found in the FPG reduction and treatment success rate among different genotypes of rs2237892.

CONCLUSION

Our results indicated that a common variant of KCNQ1, rs2237897, was associated with the efficacy of gliclazide after 8-week monotherapy in Chinese newly diagnosed type 2 diabetic patients. The FPG reduction and treatment success rate were significantly higher in carriers of CT and TT genotypes.

Fasiglifam/TAK-875, a Selective GPR40 Agonist, Improves Hyperglycemia in Rats Unresponsive to Sulfonylureas and Acts Additively with Sulfonylureas

Sulfonylureas (SUs) are widely used insulin secretagogues, but they have adverse effects including hypoglycemia and secondary failure. Fasiglifam/TAK-875, a selective GPR40 agonist, enhances glucose-stimulated insulin secretion and improves hyperglycemia. In the present study, we compared the in vivo glucose-lowering effects of fasiglifam with SUs. The risk of secondary failure of fasiglifam and the efficacy in rats desensitized to SUs were also evaluated. Moreover, we assessed whether fasiglifam was effective when combined with SUs. In diabetic neonatally streptozotocin-induced rats 1.5 days after birth (N-STZ-1.5), oral administrations of fasiglifam (3-30 mg/kg) dose dependently improved glucose tolerance; the effect was greater than that of glibenclamide at maximal effective doses (glucose AUC: fasiglifam, -37.6%; glibenclamide, -12.3%). Although the glucose-lowering effects of glibenclamide (10 mg/kg/day) were completely diminished in N-STZ-1.5 rats after 4 weeks of treatment, effects were maintained in rats receiving fasiglifam (10 mg/kg/day), even after 15 weeks. Fasiglifam (3-10 mg/kg) was still effective in two models desensitized to SUs: 15-week glibenclamide-treated N-STZ-1.5 rats and aged Zucker diabetic fatty (ZDF) rats. Acute administration of fasiglifam (3 mg/kg) and glimepiride (10 mg/kg) in combination additively decreased glucose AUC (fasiglifam, -25.3%; glimepiride, -20.0%; combination, -43.1%). Although glimepiride (10 mg/kg) decreased plasma glucose below normal in nonfasted control rats, fasiglifam (3 mg/kg) maintained normoglycemia, and no further exaggeration of hypoglycemia was observed with combination treatment. These results indicate that GPR40 agonists could be more effective and durable than SUs. Our results also provide new insights into GPR40 pharmacology and rationale for the use of GPR40 agonists in diabetic patients with SU failure.

CYP2C93 variant is associated with antidiabetes efficacy of gliclazide in Chinese type 2 diabetes patients

Aims/Introduction

The objective of the present study was to investigate the effects of CYP2C9*3 polymorphisms on the therapeutic response to gliclazide in type 2 diabetes patients.

Materials and Methods

A total of 746 incident type 2 diabetes patients were included in this study. After enrolment, patients went on 4‐week gliclazide monotherapy. Fasting plasma glucose was measured before and after treatment. Hypoglycemia episodes and lifestyle information were collected by weekly follow up. Genotyping of rs1057910 was carried out using the single base primer extension method. The t‐test, analysis of variance and chisquare‐test were used to evaluate the effects of rs1057910 alleles on the therapeutic response to gliclazide.

Results

After the therapy, fasting plasma glucose decreased significantly from 11.2 ± 2.7 mmol/L to 8.0 ± 2.2 mmol/L (P < 0.001). Patients with AC/CC genotypes of rs1057910 had a greater reduction of fasting plasma glucose (3.6 vs 3.0 mmol/L, P < 0.001; 31.4 vs 24.5%, P < 0.001) and a higher rate of treatment success (54.7 vs 37.5%, P < 0.001; 51.4 vs 32.3%, P < 0.001; 71.6 vs 48.3%, P < 0.001 for criterion 1, 2 and 3, respectively).

Conclusions

The present study showed that the polymorphism at rs1057910 significantly affected the therapeutic response of gliclazide in type 2 diabetes mellitus patients. The risk allele is associated with a greater decrease of fasting blood glucose and a higher rate of treatment success with gliclazide monotherapy.

This study demonstrated that polymorphism at rs1057910 significantly affected therapeutic response of gliclazide in type 2 diabetes mellitus patients. It associated with the decrease of FPG and the rate of treatment success in the gliclazide monotherapy.

Options for Controlling Type 2 Diabetes during Ramadan

The Muslim population is about 1.5 billion worldwide. Based on a global diabetes prevalence of 4.6%, it is estimated that there are about 50 million Muslims with diabetes around the world who observe fasting during the month of Ramadan each year. Ramadan, one of the five pillars of Islam, and which takes place during the ninth month of the Islamic calendar, involves fasting from sunrise to sunset. During the fast, Muslims are required to refrain from eating food, drinking, using medications, and smoking from dawn until after sunset, with no restrictions on food or fluid intake between sunset and dawn. Islam exempts people from the duty of fasting if they are sick, or if fasting may affect their health, as fasting for patients with diabetes carries a risk of an assortment of complications, including hypoglycemia, postprandial hyperglycemia, and metabolic complications, associated with dehydration. Nevertheless, a large number of people with diabetes who still choose to fast during Ramadan despite the advice of their doctor, and the permission received from religious authorities thus create medical challenges for themselves and their health-care providers. It is thus important for patients with diabetes who wish to fast during Ramadan to make the necessary preparations to engage in fasting as safely as possible. This review presents a guide to the care of diabetic patients during Ramadan to help them fast safely if they wish to do so.

Association between use of warfarin with common sulfonylureas and serious hypoglycemic events: retrospective cohort analysis

STUDY QUESTION

Is warfarin use associated with an increased risk of serious hypoglycemic events among older people treated with the sulfonylureas glipizide and glimepiride?

METHODS

This was a retrospective cohort analysis of pharmacy and medical claims from a 20% random sample of Medicare fee for service beneficiaries aged 65 years or older. It included 465,918 beneficiaries with diabetes who filled a prescription for glipizide or glimepiride between 2006 and 2011 (4,355,418 person quarters); 71,895 (15.4%) patients also filled a prescription for warfarin (416,479 person quarters with warfarin use). The main outcome measure was emergency department visit or hospital admission with a primary diagnosis of hypoglycemia in person quarters with concurrent fills of warfarin and glipizide/glimepiride compared with the rates in quarters with glipizide/glimepiride fills only, Multivariable logistic regression was used to adjust for individual characteristics. Secondary outcomes included fall related fracture and altered consciousness/mental status.

SUMMARY ANSWER AND LIMITATIONS

In quarters with glipizide/glimepiride use, hospital admissions or emergency department visits for hypoglycemia were more common in person quarters with concurrent warfarin use compared with quarters without warfarin use (294/416,479 v 1903/3,938,939; adjusted odds ratio 1.22, 95% confidence interval 1.05 to 1.42). The risk of hypoglycemia associated with concurrent use was higher among people using warfarin for the first time, as well as in those aged 65-74 years. Concurrent use of warfarin and glipizide/glimepiride was also associated with hospital admission or emergency department visit for fall related fractures (3919/416,479 v 20,759/3,938,939; adjusted odds ratio 1.47, 1.41 to 1.54) and altered consciousness/mental status (2490/416,479 v 14,414/3,938,939; adjusted odds ratio 1.22, 1.16 to 1.29). Unmeasured factors could be correlated with both warfarin use and serious hypoglycemic events, leading to confounding. The findings may not generalize beyond the elderly Medicare population.

WHAT THIS STUDY ADDS

A substantial positive association was seen between use of warfarin with glipizide/glimepiride and hospital admission/emergency department visits for hypoglycemia and related diagnoses, particularly in patients starting warfarin. The findings suggest the possibility of a significant drug interaction between these medications.

FUNDING, COMPETING INTERESTS, DATA SHARING

JAR and DPG receive support from the National Institute on Aging, the Commonwealth Fund, and the Leonard D. Schaeffer Center for Health Policy and Economics at the University of Southern California. ABJ receives support from the NIH Office of the Director. No additional data are available.

Antidiabetic Effects of Simple Phenolic Acids: A Comprehensive Review

Diabetes mellitus (DM) has become a major public health threat across the globe. Current antidiabetic therapies are based on synthetic drugs that very often have side effects. It has been widely acknowledged that diet plays an important role in the management of diabetes. Phenolic acids are widely found in daily foods such as fruits, vegetables, cereals, legumes, and wine and they provide biological, medicinal, and health properties. Simple phenolic acids have been shown to increase glucose uptake and glycogen synthesis, improve glucose and lipid profiles of certain diseases (obesity, cardiovascular diseases, DM, and its complication). The current review is an attempt to list out the antidiabetic effects of simple phenolic acids from medicinal plants and botanical foods.

Design, Synthesis and in Vivo Evaluation of Novel Glycosylated Sulfonylureas as Antihyperglycemic Agents

Sulphonylurea compounds have versatile activities such as antidiabetic, diuretic, herbicide, oncolytic, antimalarial, antifungal and anticancer. The present study describes the design, synthesis and in vivo testing of novel glycosylated aryl sulfonylurea compounds as antihyperglycaemic agents in streptozocine-induced diabetic mice. The rational for the introduction of the glucosamine moiety is to enhance selective drug uptake by pancreatic β-cells in order to decrease the cardiotoxic side effect commonly associated with sulfonylurea agents. 2-Deoxy-2-(4-chlorophenylsulfonylurea)-d-glucopyranose was found to be the most potent antihyperglycaemic agents among the synthesized compounds in diabetic mice. This investigation indicates the importance of this novel class as potential antihyperglycaemic agents.

Place of sulfonylureas in the management of type 2 diabetes mellitus in South Asia: A consensus statement

Since their introduction in clinical practice in the 1950's, Sulfonylureas (SUs) have remained the main-stay of pharmacotherapy in the management of type 2 diabetes. Despite their well-established benefits, their place in therapy is inappropriately being overshadowed by newer therapies. Many of the clinical issues associated with the use of SUs are agent-specific, and do not pertain to the class as such. Modern SUs (glimepiride, gliclazide MR) are backed by a large body of evidence, experience, and most importantly, outcome data, which supports their role in managing patients with diabetes. Person-centred care, i.e., careful choice of SU, appropriate dosage, timing of administration, and adequate patient counseling, will ensure that deserving patients are not deprived of the advantages of this well-established class of anti-diabetic agents. Considering their efficacy, safety, pleiotropic benefits, and low cost of therapy, SUs should be considered as recommended therapy for the treatment of diabetes in South Asia. This initiative by SAFES aims to encourage rational, safe and smart prescription of SUs, and includes appropriate medication counseling.

The Current Drug Treatment Landscape for Diabetes and Perspectives for the Future

The escalating global epidemic of type 2 diabetes mellitus has focused attention on the devastating consequences of protracted hyperglycemia. Early and effective intervention to control blood glucose is a fundamental principle of treatment guidelines, requiring assiduous use of current therapies. However, many patients do not achieve or maintain glycemic targets, emphasizing the need for further therapies. This narrative review assesses the available medicinal options to address hyperglycemia and the opportunities to develop novel agents.

Pharmacogenomics of Drug Response in Type 2 Diabetes: Toward the Definition of Tailored Therapies?

Type 2 diabetes is one of the major causes of mortality with rapidly increasing prevalence. Pharmacological treatment is the first recommended approach after failure in lifestyle changes. However, a significant number of patients shows-or develops along time and disease progression-drug resistance. In addition, not all type 2 diabetic patients have the same responsiveness to drug treatment. Despite the presence of nongenetic factors (hepatic, renal, and intestinal), most of such variability is due to genetic causes. Pharmacogenomics studies have described association between single nucleotide variations and drug resistance, even though there are still conflicting results. To date, the most reliable approach to investigate allelic variants is Next-Generation Sequencing that allows the simultaneous analysis, on a genome-wide scale, of nucleotide variants and gene expression. Here, we review the relationship between drug responsiveness and polymorphisms in genes involved in drug metabolism (CYP2C9) and insulin signaling (ABCC8, KCNJ11, and PPARG). We also highlight the advancements in sequencing technologies that to date enable researchers to perform comprehensive pharmacogenomics studies. The identification of allelic variants associated with drug resistance will constitute a solid basis to establish tailored therapeutic approaches in the treatment of type 2 diabetes.

What's next after metformin? focus on sulphonylurea: add-on or combination therapy

Introduction:

The pathophysiology of type 2 diabetes (T2DM) mainly focused on insulin resistance and insulin deficiency over the past decades. Currently, the pathophysiologies expanded to ominous octet and guidelines were updated with newer generation of antidiabetic drug classes. However, many patients had yet to achieve their target glycaemic control. Although all the guidelines suggested metformin as first line, there was no definite consensus on the second line drug agents as variety of drug classes were recommended.

Objectives:

The aim of this review was to evaluate the drug class after metformin especially sulphonylurea and issues around add-on or fixed dose combination therapy.

Methods:

Extensive literature search for English language articles, clinical practice guidelines and references was performed using electronic databases.

Results:

Adding sulphonylurea to metformin targeted both insulin resistance and insulin deficiency. Sulphonylurea was efficacious and cheaper than thiazolidinedione, dipeptidyl peptidase-4 inhibitor, glucagon-like peptide 1 analogue and insulin. The main side effect of sulphonylurea was hypoglycaemia but there was no effect on the body weight when combining with metformin. Fixed dose sulphonylurea/metformin was more efficacious at lower dose and reported to have fewer side effects with better adherence. Furthermore, fixed dose combination was cheaper than add-on therapy.

In conclusion, sulphonylurea was feasible as the second line agent after metformin as the combination targeted on two pathways, efficacious, cost-effective and had long safety history. Fixed dose combination tablet could improve patient’s adherence and offered an inexpensive and more efficacious option regardless of original or generic product as compared to add-on therapy.

Discovery of DS-1558: A Potent and Orally Bioavailable GPR40 Agonist

GPR40 is a G protein-coupled receptor that is predominantly expressed in pancreatic β-cells. GPR40 agonists stimulate insulin secretion in the presence of high glucose concentration. On the basis of this mechanism, GPR40 agonists are possible novel insulin secretagogues with reduced or no risk of hypoglycemia. The improvement of in vitro activity and metabolic stability of compound 1 led to the discovery of 13, (3S)-3-ethoxy-3-(4-{[(1R)-4-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]oxy}phenyl)propanoic acid, as a potent and orally available GPR40 agonist. Compound 13 (DS-1558) was found to have potent glucose lowering effects during an oral glucose tolerance test in ZDF rats.

The association between glucose-lowering drug use and mortality among breast cancer patients with type 2 diabetes

This study assessed the association between glucose-lowering drug (GLD) use, including metformin, sulphonylurea derivatives and insulin, after breast cancer diagnosis and breast cancer-specific and all-cause mortality. 1763 breast cancer patients, diagnosed between 1998 and 2010, with type 2 diabetes were included. Cancer information was retrieved from English cancer registries, prescription data from the UK Clinical Practice Research Datalink and mortality data from the Office of National Statistics (up to January 2012). Time-varying Cox regression models were used to calculate HRs and 95 % CIs for the association between GLD use and breast cancer-specific and all-cause mortality. In 1057 patients with diabetes before breast cancer, there was some evidence that breast cancer-specific mortality decreased with each year of metformin use (adjusted HR 0.88; 95 % CI 0.75-1.04), with a strong association seen with over 2 years of use (adjusted HR 0.47; 95 % CI 0.26-0.82). Sulphonylurea derivative use for less than 2 years was associated with increased breast cancer-specific mortality (adjusted HR 1.70; 95 % CI 1.18-2.46), but longer use was not (adjusted HR 0.94; 95 % CI 0.54-1.66). In 706 patients who developed diabetes after breast cancer, similar patterns were seen for metformin, but sulphonylurea derivative use was strongly associated with cancer-specific mortality (adjusted HR 3.64; 95 % CI 2.16-6.16), with similar estimates for short- and long-term users. This study provides some support for an inverse association between, mainly long-term, metformin use and (breast cancer-specific) mortality. In addition, sulphonylurea derivative use was associated with increased breast cancer-specific mortality, but this should be interpreted cautiously, as it could reflect selective prescribing in advanced cancer patients.

Optimal utilisation of sulphonylureas in resource-constrained settings

Abstract

Sulphonylureas (SUs) are oral anti-diabetic drugs (OADs) that were introduced more than 60 years ago. Clinicians are familiar with their use and they remain extensively used. However, the SU class is associated with adverse effects of weight gain and hypoglycaemia. In addition, their effects on cardiovascular events remain contentious. Newer classes of anti-diabetic agents have been developed and these agents are weight neutral (di-peptidyl peptidase IV inhibitors), while others reduce weight (glucagon-like peptide analogues and sodium glucose co-transporter inhibitors). Furthermore, the newer agents are less likely to cause hypoglycaemia and have a potentially better cardiovascular safety profile. However, the newer agents are more costly than SUs and their long-term safety is unknown. It is therefore likely that SUs will continue to be used, and more so in resource-limited settings. One may mitigate the adverse effects of weight gain and hypoglycaemia associated with the SU class by using members within this class that are less probable to cause these adverse effects. Furthermore, the specific SU must be used at the lowest effective therapeutic dose. In patients at high risk of SU-induced hypoglycaemic episodes (frail, clinically significant renal impairment), or patients in whom hypoglycaemic episodes may have devastating effects (bus drivers), newer anti-diabetic agents may be a justifiable alternative option.

Characterization of the heterozygous glucokinase knockout mouse as a translational disease model for glucose control in type 2 diabetes

BACKGROUND AND PURPOSE

The global heterozygous glucokinase (GK) knockout (gk(wt/del)) male mouse, fed on a high-fat (60% by energy) diet, has provided a robust and reproducible model of hyperglycaemia. This model could be highly relevant to some facets of human type 2 diabetes (T2D). We aimed to investigate the ability of standard therapeutic agents to lower blood glucose at translational doses, and to explore the glucose-lowering potential of novel glucokinase activators (GKAs) in this model.

EXPERIMENTAL APPROACH

We measured the ability of insulin, metformin, glipizide, exendin-4 and sitagliptin, after acute or repeat dose administration, to lower free-feeding glucose levels in gk(wt/del) mice. Further, we measured the ability of novel GKAs, GKA23, GKA71 and AZD6370 to control glucose either alone or in combination with some standard agents.

KEY RESULTS

A single dose of insulin (1 unit·kg(-1)), metformin (150, 300 mg·kg(-1)), glipizide (0.1, 0.3 mg·kg(-1)), exendin-4 (2, 20 μg·kg(-1)) and GKAs reduced free-feeding glucose levels. Sitagliptin (10 mg·kg(-1)), metformin (300 mg·kg(-1)) and AZD6370 (30, 400 mg·kg(-1)) reduced glucose excursions on repeat dosing. At a supra-therapeutic dose (400 mg·kg(-1)), AZD6370 also lowered basal levels of glucose without inducing hypoglycaemia.

CONCLUSION AND IMPLICATIONS

Standard glucose-lowering therapeutic agents demonstrated significant acute glucose lowering in male gk(wt/del) mice at doses corresponding to therapeutic free drug levels in man, suggesting the potential of these mice as a translatable model of human T2D. Novel GKAs also lowered glucose in this mouse model.

Release and swelling studies of an innovative antidiabetic-bile acid microencapsulated formulation, as a novel targeted therapy for diabetes treatment

In previous studies carried out in our laboratory, a bile acid formulation exerted a hypoglycaemic effect in a rat model of type 1 diabetes (T1D). When the antidiabetic drug gliclazide was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-deoxycholic acid (G-DCA), with good structural properties, excipient compatibility and which exhibited pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH controlled properties of this new formulation. The aim is also to examine the effect of DCA on G release kinetics at various pH values and different temperatures. Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared including: G-SA (control) and G-DCA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, 3, 7.4 and 7.8 and temperatures of 25 °C and 37 °C. The new formulation is further optimised by the addition of DCA. DCA reduced bead-swelling of the microcapsules at pH 7.8 and 3 at 25 °C and 37 °C, and even though bead size remains similar after DCA addition, the percentage of G release was enhanced at high pH values (pH 7.4 and 7.8, p < 0.01). The new formulation exhibits colon-targeted delivery and the addition of DCA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and DCA to the lower intestine.

The sodium glucose cotransporter type 2 inhibitor empagliflozin preserves β-cell mass and restores glucose homeostasis in the male zucker diabetic fatty rat

Type 2 diabetes is characterized by impaired β-cell function associated with progressive reduction of insulin secretion and β-cell mass. Evidently, there is an unmet need for treatments with greater sustainability in β-cell protection and antidiabetic efficacy. Through an insulin and β cell-independent mechanism, empagliflozin, a specific sodium glucose cotransporter type 2 (SGLT-2) inhibitor, may potentially provide longer efficacy. This study compared the antidiabetic durability of empagliflozin treatment (10 mg/kg p.o.) against glibenclamide (3 mg/kg p.o.) and liraglutide (0.2 mg/kg s.c.) on deficient glucose homeostasis and β-cell function in Zucker diabetic fatty (ZDF) rats. Empagliflozin and liraglutide led to marked improvements in fed glucose and hemoglobin A1c levels, as well as impeding a progressive decline in insulin levels. In contrast, glibenclamide was ineffective. Whereas the effects of liraglutide were less pronounced at week 8 of treatment compared with week 4, those of empagliflozin remained stable throughout the study period. Similarly, empagliflozin improved glucose tolerance and preserved insulin secretion after both 4 and 8 weeks of treatment. These effects were reflected by less reduction in β-cell mass with empagliflozin or liraglutide at week 4, whereas only empagliflozin showed β-cell sparing effects also at week 8. Although this study cannot be used to dissociate the absolute antidiabetic efficacy among the different mechanisms of drug action, the study demonstrates that empagliflozin exerts a more sustained improvement of glucose homeostasis and β-cell protection in the ZDF rat. In comparison with other type 2 diabetic treatments, SGLT-2 inhibitors may through insulin-independent pathways thus enhance durability of β-cell protection and antidiabetic efficacy.

TAK-875, a GPR40/FFAR1 agonist, in combination with metformin prevents progression of diabetes and β-cell dysfunction in Zucker diabetic fatty rats

BACKGROUND AND PURPOSE

TAK-875, a selective GPCR40/free fatty acid receptor 1 agonist, improves glycaemic control by increasing glucose-dependent insulin secretion. Metformin is a first-line drug for treatment of type 2 diabetes that improves peripheral insulin resistance. Based on complementary mechanism of action, combining these agents is expected to enhance glycaemic control. Here, we evaluated the chronic effects of TAK-875 monotherapy and combination therapy with metformin in diabetic rats.

EXPERIMENTAL APPROACH

Long-term effects on glycaemic control and β-cell function were evaluated using Zucker diabetic fatty (ZDF) rats, which develop diabetes with hyperlipidaemia and progressive β-cell dysfunction.

KEY RESULTS

Single doses of TAK-875 (3-10 mg·kg(-1) ) and metformin (50-150 mg·kg(-1) ) significantly improved both postprandial and fasting hyperglycaemia, and additive improvements were observed in their combination. Six-week treatment with TAK-875 (10 mg·kg(-1) , b.i.d.) significantly decreased glycosylated Hb (GHb) by 1.7%, and the effect was additively enhanced by combination with metformin (50 mg·kg(-1) , q.d.; GHb: -2.4%). This improvement in glycaemic control in the combination group was accompanied by significant 3.2-fold increase in fasting plasma insulin levels. Pancreatic insulin content was maintained at a level comparable to that in normal rats by combination treatment (vehicle: 26, combination: 67.1; normal lean: 69.1 ng·mg(-1) pancreas) without affecting pancreatic glucagon content. Immunohistochemical analyses revealed normal morphology, enhanced pancreas duodenum homeobox-1 expression and increased PCNA-positive cells in islets of the combination group.

CONCLUSION AND IMPLICATIONS

Our results indicate that combination therapy with TAK-875 and metformin could be a valuable strategy for glycaemic control and β-cell preservation in type 2 diabetes.

Gymnemic acids inhibit sodium-dependent glucose transporter 1

To evaluate the activity of botanicals used in Chinese Traditional Medicine as hypoglycemic agents for diabetes type II prevention and/or treatment, extracts prepared from 26 medicinal herbs were screened for their inhibitory activity on sodium-dependent glucose transporter 1 (SGLT1) by using two-electrode voltage-clamp recording of glucose uptake in Xenopus laevis oocytes microinjected with cRNA for SGLT1. Showing by far the strongest SGLT1 inhibitory effect, the phytochemicals extracted from Gymnema sylvestre (Retz.) Schult were located by means of activity-guided fractionation and identified as 3-O-β-D-glucuronopyranosyl-21-O-2-tigloyl-22-O-2-tigloyl gymnemagenin (1) and 3-O-β-D-glucuronopyranosyl-21-O-2-methylbutyryl-22-O-2-tigloyl gymnemagenin (2) by means of LC-MS/MS, UPLC-TOF/MS, and 1D/2D-NMR experiments. Both saponins exhibited low IC50 values of 5.97 (1) and 0.17 μM (2), the latter of which was in the same range as found for the high-affinity inhibitor phlorizin (0.21 μM). As SGLT1 is found in high levels in brush-border membranes of intestinal epithelial cells, these findings demonstrate for the first time the potential of these saponins for inhibiting electrogenic glucose uptake in the gastrointestinal tract.

The diabetic patient in Ramadan

During the month of Ramadan, all healthy, adult Muslims are required to fast from dawn to sunset. Fasting during Ramadan involves abstaining from food, water, beverages, smoking, oral drugs, and sexual intercourse. Although the Quran exempts chronically ill from fasting, many Muslims with diabetes still fast during Ramadan. Patients with diabetes who fast during the month of Ramadan can have acute complications. The risk of complications in fasting individuals with diabetes increases with longer periods of fasting. All patients with diabetes who wish to fast during Ramadan should be prepared by undergoing a medical assessment and engaging in a structured education program to undertake the fast as safely as possible. Although some guidelines do exist, there is an overwhelming need for better designed clinical trials which could provide us with evidence-based information and guidance in the management of patients with diabetes fasting Ramadan.

Label-free cell phenotypic profiling decodes the composition and signaling of an endogenous ATP-sensitive potassium channel

Current technologies for studying ion channels are fundamentally limited because of their inability to functionally link ion channel activity to cellular pathways. Herein, we report the use of label-free cell phenotypic profiling to decode the composition and signaling of an endogenous ATP-sensitive potassium ion channel (K_ATP) in HepG2C3A, a hepatocellular carcinoma cell line. Label-free cell phenotypic agonist profiling showed that pinacidil triggered characteristically similar dynamic mass redistribution (DMR) signals in A431, A549, HT29 and HepG2C3A, but not in HepG2 cells. Reverse transcriptase PCR, RNAi knockdown, and K_ATP blocker profiling showed that the pinacidil DMR is due to the activation of SUR2/Kir6.2 K_ATP channels in HepG2C3A cells. Kinase inhibition and RNAi knockdown showed that the pinacidil activated K_ATP channels trigger signaling through Rho kinase and Janus kinase-3, and cause actin remodeling. The results are the first demonstration of a label-free methodology to characterize the composition and signaling of an endogenous ATP-sensitive potassium ion channel.

Discovery of 3-aryl-3-ethoxypropanoic acids as orally active GPR40 agonists

The G protein-coupled receptor 40 (GPR40) mediates enhancement of glucose-stimulated insulin secretion in pancreatic β cells. The GPR40 agonist has been attracting attention as a novel insulin secretagogue with glucose dependency for the treatment of type 2 diabetes. The optimization study of compound 1 led to a potent and bioavailable GPR40 agonist 24, which showed insulin secretion and glucose lowering effects in rat OGTT. Compound 24 is a potential lead compound for a novel insulin secretagogue with a low risk of hypoglycemia.

Meglitinide analogues in adolescent patients with HNF1A-MODY (MODY 3)

For pediatric patients with hepatocyte nuclear factor-1A (HNF1A)-maturity-onset diabetes of the young (MODY 3), treatment with sulfonylureas is recommended. In adults with HNF1A-MODY, meglitinide analogues achieve lower postprandial glucose levels and pose a lower risk of delayed hypoglycemia compared with sulfonylureas. This therapy has not yet been reviewed in pediatric patients. We report on meglitinide analogue treatment in 3 adolescents with HNF1A-MODY. Case 1 (14-year-old girl) was diagnosed asymptomatically but had an hemoglobin A1c (HbA1c) level of 7.4%; her father had been recently diagnosed with HNF1A-MODY. With repaglinide, her HbA1c level decreased to 5.5%, with no hypoglycemic episodes. Case 2 (14-year-old boy) was diagnosed incidentally with glucosuria (HbA1c level: 7.0%) and was treated with insulin. After the HNF1A-MODY diagnosis, he was switched to glibenclamide. Due to several hypoglycemic episodes, treatment was changed to nateglinide and his HbA1c level decreased to 6.2% with no further hypoglycemic episodes. Case 3 (11-year-old girl) presented with polyuria and polydipsia (HbA1c level: 10.1%) and was initially treated with insulin. After the HNF1A-MODY diagnosis, treatment was changed to repaglinide. She was obese (BMI: 28.8 kg/m(2); z-score: +2.2), and glucose control with repaglinide alone was insufficient. Therefore, neutral protamine Hagedorn insulin (0.27 U/kg per day) was added. With this combination therapy, her HbA1c level decreased to 8.2%. The use of meglitinides in these 3 adolescent patients was well tolerated and effective. Furthermore, hypoglycemic episodes were rare compared with treatment with insulin or sulfonylureas. We therefore suggest considering meglitinides as the primary oral treatment option for adolescents suffering from HNF1A-MODY.

Head-to-head comparison of dipeptidyl peptidase-IV inhibitors and sulfonylureas - a meta-analysis from randomized clinical trials

BACKGROUND

Dipeptidyl peptidase-IV (DPP-4) inhibitors and sulfonylureas are two important second-line anti-diabetic agents. The objective of this research was to evaluate the efficacy and safety of DPP-4 inhibitors compared with sulfonylureas by meta-analytic approach of available randomized studies.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases up to 30 June 2013, collecting all randomized clinical trials with a treatment duration of ≥18weeks. Data on glycated haemoglobin (HbA1c ), body weight, hypoglycaemia, total adverse events, and cardiovascular events were retrieved and analysed.

RESULTS

The analysis included 12 randomized studies comprising 10 982 patients with type 2 diabetes mellitus. On the basis of meta-analysis, sulfonylureas lowered HbA1c significantly more than DPP-4 inhibitors with weighted mean difference (WMD) of 0.105 [95% confidence interval (CI) 0.103 to 0.107]. The results were consistent in trials with longer (>32 weeks) or shorter (≤32 weeks) duration; however, DPP-4 inhibitors showed greater reduction in HbA1c compared with the second-generation sulfonylureas and in patients with baseline eGFR < 50 mL/min/1.73 m(2) . Patients treated with DPP-4 inhibitors are less likely to achieve HbA1c  < 7% compared with sulfonylureas [Mantel-Haenszel odds ratio (MH-OR) 0.91; 95% CI 0.84 to 0.99]. DPP-4 xinhibitors were associated with a reduction in body weight (WMD -1.652; 95% CI -1.658 to -1.646) and lower risk of hypoglycaemia (MH-OR, 0.13; 95% CI 0.11 to 0.16), total adverse events (MH-OR, 0.79; 95% CI 0.72 to 0.87), and cardiovascular events (MH-OR, 0.53; 95% CI 0.32 to 0.87) compared with sulfonylureas.

CONCLUSION

Although DPP-4 inhibitors are less efficacious compared with sulfonylureas, they demonstrate a beneficial effect on body weight, episodes of hypoglycaemia, and total adverse events.

Disruption of ion homeostasis in the neurogliovascular unit underlies the pathogenesis of ischemic cerebral edema

Cerebral edema is a major cause of morbidity and mortality following ischemic stroke, but its underlying molecular pathophysiology is incompletely understood. Recent data have revealed the importance of ion flux via channels and transporters expressed in the neurogliovascular unit in the development of ischemia-triggered cytotoxic edema, vasogenic edema, and hemorrhagic conversion. Disruption of homeostatic mechanisms governing cell volume regulation and epithelial/endothelial ion transport due to ischemia-associated energy failure results in the thermodynamically driven re-equilibration of solutes and water across the CSF-blood and blood-brain barriers that ultimately increases the brain's extravascular volume. Additionally, hypoxia, inflammation, and other stress-triggered increases in the functional expression of ion channels and transporters normally expressed at low levels in the neurogliovascular unit cause disruptions in ion homeostasis that contribute to ischemic cerebral edema. Here, we review the pathophysiological significance of several molecular mediators of ion transport expressed in the neurogliovascular unit, including targets of existing FDA-approved drugs, which might be potential nodes for therapeutic intervention.

Standard and Novel Treatment Options for Metabolic Syndrome and Diabetes Mellitus

OPINION STATEMENT

Type II diabetes and metabolic syndrome are 2 intertwined conditions that are critical to the healthcare landscape in the United States and abroad. Patients with either diabetes or metabolic syndrome can have a dramatically increased risk of developing cardiovascular disease. Numerous treatment options have existed for some time, which include nonpharmacologic and pharmacologic therapies. In addition, within the last decade, a multiple of novel treatment options have emerged for the management of hyperglycemia in particular. By targeting novel pathways beyond the secretion and supply of insulin, these new therapeutics provide a valuable adjunct to the currently available therapies for diabetes and metabolic syndrome. Here we discuss the current guideline-driven usage of standard therapies with some novel indications. In addition, we discuss the novel therapies for the treatment of hyperglycemia, their mechanisms of action, and appropriate therapeutic indications.

Comparative efficacy of glimepiride and metformin in monotherapy of type 2 diabetes mellitus: meta-analysis of randomized controlled trials

BACKGROUND

Metformin treatment has been the most recommended monotherapy of type 2 diabetes mellitus (T2DM) for decades but is challenged by new antidiabetic drugs. This study conducted a meta-analysis of randomized controlled trials (RCT) comparing the efficacy of metformin and glimepiride in monotherapy of T2DM.

METHODS

A literature search for RCTs on glimepiride and metformin was conducted on the bibliographic databases, including PubMed, Cochrane Library and ScienceDirect, from their inceptions to 25 Mar 2013. All RCTs were selected according to pre-specified eligibility criteria. The quality of articles was assessed with the Cochrane's risk of bias tool. Statistical meta-analysis evaluated the overall effects and biochemical indices of T2DM. Sensitivity and subgroup analyses evaluated the robustness and explained the heterogeneity of the results. Begg and Egger's tests quantified possible publication biases. Results were represented as "standard mean difference or odds ratio [95% confidence internals] P value".

RESULTS

Fifteen RCTs with 1681 adult T2DM patients were included for meta-analysis. Metformin was not better than glimepiride in overall efficacy in controlling the levels of HbA1c, postprandial blood sugar (PPBS), fasting plasma insulin (FINS), systolic and diastolic blood pressures (SBP and DBP), and high density lipoprotein (HDL). Metformin was only more effective than glimepiride in controlling the levels of total cholesterol (TC, 0.33 [0.03, 0.63], P = 0.03), low-density lipoprotein (LDL, 0.35 [0.16, 0.53], P = 0.0002) and triglycerides (TG, 0.26 [0.05, 0.46], P = 0.01). Odds ratios of adverse events showed that glimepiride was more likely to induce hypoglycemia episodes and metformin was with a higher risk of gastrointestinal upset.

CONCLUSION

Metformin was not significantly better than glimepiride in glycemic control of T2DM, suggesting that glimepiride would be a good choice second to metformin in the monotherapy of T2DM.

A pharmacologic approach to the use of glyburide in pregnancy

Despite widespread use of glyburide to treat pregnancy-related hyperglycemia, the dosing regimen is based in large part on pharmacokinetic and pharmacodynamic studies in men and nonpregnant women. Like many medications used by pregnant women, adequate pharmacokinetic and pharmacodynamic data in pregnancy have been sorely lacking. This lack of information can lead to both overdosing with excessive side effects and underdosing with an inadequate therapeutic response. Both of these problems may apply to glyburide use in pregnancy. This commentary provides a pharmacologic basis for altering the glyburide administration regimen. Taking glyburide 1 hour before a meal may improve efficacy in patients with pregnancy-related hyperglycemia.

Effects of Fatty Acids and Glycation on Drug Interactions with Human Serum Albumin

The presence of elevated glucose concentrations in diabetes is a metabolic change that leads to an increase in the amount of non-enzymatic glycation that occurs for serum proteins. One protein that is affected by this process is the main serum protein, human serum albumin (HSA), which is also an important carrier agent for many drugs and fatty acids in the circulatory system. Sulfonylureas drugs, used to treat type 2 diabetes, are known to have significant binding to HSA. This study employed ultrafiltration and high-performance affinity chromatography to examine the effects of HSA glycation on the interactions of several sulfonylurea drugs (i.e., acetohexamide, tolbutamide and gliclazide) with fatty acids, whose concentrations in serum are also affected by diabetes. Similar overall changes in binding were noted for these drugs with normal HSA or glycated HSA and in the presence of the fatty acids. For most of the tested drugs, the addition of physiological levels of the fatty acids to normal HSA and glycated HSA produced weaker binding. At low fatty acid concentrations, many of these systems followed a direct competition model while others involved a mixed-mode interaction. In some cases, there was a change in the interaction mechanism between normal HSA and glycated HSA, as seen with linoleic acid. Systems with only direct competition also gave notable changes in the affinities of fatty acids at their sites of drug competition when comparing normal HSA and glycated HSA. This research demonstrated the importance of considering how changes in the concentrations and types of metabolites (e.g., in this case, glucose and fatty acids) can alter the function of a protein such as HSA and its ability to interact with drugs or other agents.

Potent and Orally Bioavailable GPR142 Agonists as Novel Insulin Secretagogues for the Treatment of Type 2 Diabetes

GPR142 is a G protein-coupled receptor that is predominantly expressed in pancreatic β-cells. GPR142 agonists stimulate insulin secretion in the presence of high glucose concentration, so that they could be novel insulin secretagogues with reduced or no risk of hypoglycemia. We report here the optimization of HTS hit compound 1 toward a proof of concept compound 33, which showed potent glucose lowering effects during an oral glucose tolerance test in mice and monkeys.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Role of Kir6.2 subunits of ATP-sensitive potassium channels in endotoxemia-induced cardiac dysfunction

Background

Cardiac dysfunction is well-described in endotoxemia and diagnosed in up to 60% of patients with endotoxic shock. ATP-sensitive potassium (K_ATP) channels are critical to cardiac function. This study investigates the role of Kir6.2 subunits of K_ATP channels on cardiac dysfunction in lipopolysaccharide (LPS)-induced endotoxemia.

Methods

Kir6.2 subunits knockout (Kir6.2^−/−) and wild-type (WT) mice were injected with LPS to induce endotoxemia. Cardiac function was monitored by echocardiography. Left ventricles were taken for microscopy (both light and electron) and TUNEL examination. Serum lactate dehydrogenase (LDH) and creatine kinase (CK) activities, and tumor necrosis factor-α (TNF-α) levels in both serum and left ventricular tissues were determined.

Results

Compared to WT, Kir6.2^−/− mice showed significantly declined cardiac function 360 min after LPS administration, aggravated myocardial damage and elevated serum LDH and CK activities. Apoptotic cells were obviously increased in heart tissues from Kir6.2^−/− mice at 90, 180 and 360 min. TNF-α expression in both serum and heart tissues of Kir6.2^−/− mice was significantly increased.

Conclusions

We conclude that Kir6.2 subunits are critical in resistance to endotoxemia-induced cardiac dysfunction through reducing myocardial damage by inhibition of apoptosis and inflammation. K_ATP channels blockers are extensively used in the treatment of diabetes, their potential role should therefore be considered in the clinic when patients treated with antidiabetic sulfonylureas are complicated by endotoxemia.

Development of affinity microcolumns for drug-protein binding studies in personalized medicine: interactions of sulfonylurea drugs with in vivo glycated human serum albumin

This report used high-performance affinity microcolumns to examine the changes in binding by sulfonylurea drugs to in vivo glycated HSA that had been isolated from individual patients with diabetes. An immunoextraction approach was developed to isolate HSA and glycated HSA from clinical samples, using only 20 μL of plasma or serum and 6-12 nmol of protein to prepare each affinity microcolumn. It was found that the affinity microcolumns could be used in either frontal analysis or zonal elution studies, which typically required only 4-8 min per run. The microcolumns had good stability and allowed data to be obtained for multiple drugs and experimental conditions over hundreds of sample application cycles. Both the overall binding, as measured by frontal analysis, and site-specific interactions, as examined by zonal elution, showed good agreement with previous data that had been obtained for in vitro glycated HSA with similar levels of modification. It was also possible to directly compare the changes in site-specific binding that occurred between sulfonylurea drugs or as the level of HSA glycation was varied. This method is not limited to clinical samples of glycated HSA but could be adapted for work with other modified proteins of interest in personalized medicine.