Pro- and Antiarrhythmic Actions of Sulfonylureas: Mechanistic and Clinical Evidence

Sudden cardiac death due to ventricular arrhythmia in diabetes mellitus: A bench to bedside review

Diabetes mellitus (DM) confers an increased risk of sudden cardiac death (SCD) independent of its associated cardiovascular comorbidities. DM induces adverse structural, electrophysiologic, and autonomic cardiac remodeling that can increase one's risk of ventricular arrhythmias and SCD. Although glycemic control and prevention of microvascular and macrovascular complications are cornerstones in the management of DM, they are not adequate for the prevention of SCD. In this narrative review, we describe the contribution of DM to the pathophysiologic mechanism of SCD beyond its role in atherosclerotic cardiovascular disease and heart failure. On the basis of this pathophysiologic framework, we outline potential preventive and therapeutic strategies to mitigate the risk of SCD in this population of high-risk patients.

Non-radioactive Rb+ Efflux Assay for Screening KATP Channel Modulators

ATP-sensitive potassium (KATP) channels function as metabolic sensors that link cell membrane excitability to the cellular energy status by controlling potassium ion (K+) flow across the cell membrane according to intracellular ATP and ADP concentrations. As such, KATP channels influence a broad spectrum of physiological processes, including insulin secretion and cardiovascular functions. KATP channels are hetero-octamers, consisting of four inward rectifier potassium channel subunits, Kir6.1 or Kir6.2, and four sulfonylurea receptors (SURs), SUR1, SUR2A, or SUR2B. Different Kir6 and SUR isoforms assemble into KATP channel subtypes with distinct tissue distributions and physiological functions. Mutations in the genes encoding KATP channel subunits underlie various human diseases. Targeted treatment for these diseases requires subtype-specific KATP channel modulators. Rubidium ions (Rb+) also pass through KATP channels, and Rb+ efflux assays can be used to assess KATP channel function and activity. Flame atomic absorption spectroscopy (Flame-AAS) combined with microsampling can measure Rb+ in small volume, which provides an efficient tool to screen for compounds that alter KATP channel activity in Rb+ efflux assays. In this chapter, we describe a detailed protocol for Rb+ efflux assays designed to identify new KATP channel modulators with potential therapeutic utilities.

Hypoxia Promotes Atrial Tachyarrhythmias via Opening of ATP-Sensitive Potassium Channels

BACKGROUND

Hypoxia-ischemia predisposes to atrial arrhythmia. Atrial ATP-sensitive potassium channel (KATP) modulation during hypoxia has not been explored. We investigated the effects of hypoxia on atrial electrophysiology in mice with global deletion of KATP pore-forming subunits.

METHODS

Whole heart KATP RNA expression was probed. Whole-cell KATP current and action potentials were recorded in isolated wild-type (WT), Kir6.1 global knockout (6.1-gKO), and Kir6.2 global knockout (6.2-gKO) murine atrial myocytes. Langendorff-perfused hearts were assessed for atrial effective refractory period (ERP), conduction velocity, wavefront path length (WFPL), and arrhymogenicity under normoxia/hypoxia using a microelectrode array and programmed electrical stimulation. Heart histology was assessed.

RESULTS

Expression patterns were essentially identical for all KATP subunit RNA across human heart, whereas in mouse, Kir6.1 and SUR2 (sulphonylurea receptor subunit) were higher in ventricle than atrium, and Kir6.2 and SUR1 were higher in atrium. Compared with WT, 6.2-gKO atrial myocytes had reduced tolbutamide-sensitive current and action potentials were more depolarized with slower upstroke and reduced peak amplitude. Action potential duration was prolonged in 6.1-gKO atrial myocytes, absent of changes in other ion channel gene expression or atrial myocyte hypertrophy. In Langendorff-perfused hearts, baseline atrial ERP was prolonged and conduction velocity reduced in both KATP knockout mice compared with WT, without histological fibrosis. Compared with baseline, hypoxia led to conduction velocity slowing, stable ERP, and WFPL shortening in WT and 6.1-gKO hearts, whereas WFPL was stable in 6.2-gKO hearts due to ERP prolongation with conduction velocity slowing. Tolbutamide reversed hypoxia-induced WFPL shortening in WT and 6.1-gKO hearts through ERP prolongation. Atrial tachyarrhythmias inducible with programmed electrical stimulation during hypoxia in WT and 6.1-gKO mice correlated with WFPL shortening. Spontaneous arrhythmia was not seen.

CONCLUSIONS

KATP block/absence leads to cellular and tissue level atrial electrophysiological modification. Kir6.2 global knockout prevents hypoxia-induced atrial WFPL shortening and atrial arrhythmogenicity to programmed electrical stimulation. This mechanism could be explored translationally to treat ischemically driven atrial arrhythmia.

Sulphonylureas versus metformin and the risk of ventricular arrhythmias among people with type 2 diabetes: A population-based cohort study

AIM

To determine whether the use of sulphonylurea monotherapy, compared with metformin monotherapy, is associated with an increased risk of ventricular arrhythmia (VA) among patients initiating pharmacotherapy for type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted a population-based cohort study using electronic health data extracted from the UK's Clinical Practice Research Datalink Aurum. Using the active comparator, new-user cohort design, we compared rates of VA among patients aged 18 years or older using sulphonylurea monotherapy with those using metformin monotherapy as their initial pharmacological treatment for type 2 diabetes from April 1998 to December 2019. We used a Cox proportional hazards model with inverse probability of treatment weighting by propensity score to estimate the adjusted hazard ratio (aHR) and a corresponding bootstrap 95% confidence interval (CI) for VA with sulphonylurea monotherapy versus metformin monotherapy.

RESULTS

The cohort included 92 638 new users of sulphonylurea and 506 882 new users of metformin. A total of 279 VA events occurred among sulphonylurea users (rate per 10 000 person-years: 25.5, 95% CI: 22.7 to 28.7) and 1537 VA events occurred among metformin users (rate per 10 000 person-years: 18.5, 95% CI: 17.6 to 19.5). Compared with metformin, sulphonylureas were associated with an increased risk of VA (aHR: 1.42, 95% CI: 1.18 to 1.69).

CONCLUSIONS

Sulphonylureas are associated with an increased risk of VA when used as first-line therapy for type 2 diabetes relative to metformin use. This increased risk should be considered when prescribing sulphonylureas as an initial treatment for type 2 diabetes.

Sulfonylurea Is Associated With Higher Risks of Ventricular Arrhythmia or Sudden Cardiac Death Compared With Metformin: A Population‐Based Cohort Study

Background

Commonly prescribed diabetic medications such as metformin and sulfonylurea may be associated with different arrhythmogenic risks. This study compared the risk of ventricular arrhythmia or sudden cardiac death between metformin and sulfonylurea users in patients with type 2 diabetes.

Methods and Results

Patients aged ≥40 years who were diagnosed with type 2 diabetes or prescribed antidiabetic agents in Hong Kong between January 1, 2009, and December 31, 2009, were included and followed up until December 31, 2019. Patients prescribed with both metformin and sulfonylurea or had prior myocardial infarction were excluded. The study outcome was a composite of ventricular arrhythmia or sudden cardiac death. Metformin users and sulfonylurea users were matched at a 1:1 ratio by propensity score matching. The matched cohort consisted of 16 596 metformin users (47.70% men; age, 68±11 years; mean follow‐up, 4.92±2.55 years) and 16 596 sulfonylurea users (49.80% men; age, 70±11 years; mean follow‐up, 4.93±2.55 years). Sulfonylurea was associated with higher risk of ventricular arrhythmia or sudden cardiac death than metformin hazard ratio (HR, 1.90 [95% CI, 1.73–2.08]). Such difference was consistently observed in subgroup analyses stratifying for insulin usage or known coronary heart disease.

Conclusions

Sulfonylurea use is associated with higher risk of ventricular arrhythmia or sudden cardiac death than metformin in patients with type 2 diabetes.

The Effects of 6 Common Antidiabetic Drugs on Anti-PD1 Immune Checkpoint Inhibitor in Tumor Treatment

Diabetes and cancer are common diseases and are frequently diagnosed in the same individual. These patients need to take antidiabetic drugs while receiving antitumor drugs therapy. Recently, immunotherapy offers significant advances for cancer treatment. However, it is unclear whether antidiabetic drugs affect immunotherapy. Here, by employing syngeneic mouse colon cancer model and melanoma model, we studied the effects of 6 common antidiabetic drugs on anti-PD1 immune checkpoint inhibitor in tumor treatment, including acarbose, sitagliptin, metformin, glimepiride, pioglitazone, and insulin. We found that acarbose and sitagliptin enhanced the tumor inhibition of anti-PD1, and metformin had no effect on the tumor inhibition of anti-PD1, whereas glimepiride, pioglitazone, and insulin weakened the tumor inhibition of anti-PD1. Our study suggests that cancer patients receiving anti-PD1 antibody therapy need serious consideration when choosing antidiabetic drugs. In particular, acarbose significantly inhibited tumor growth and further enhanced the therapeutic effect of anti-PD1, which can be widely used in tumor therapy. Based on this study, further clinical trials are expected.

Polymeric micelles loaded with glyburide and vanillic acid: I. Formulation development, in-vitro characterization and bioavailability studies

The co-formulation of glyburide (Gly) and vanillic acid (VA) as such in the form of nanomedicine has never been explored to treat metabolic diseases including type 2 diabetes mellitus. Both the drugs possess dissolution rate-limited oral bioavailability leading to poor therapeutic efficacy. Hence, co-loading these drugs into a nanocarrier could overcome their poor oral bioavailability related challenges. Owing to this objective, both drugs were co-loaded in amphiphilic polymeric micelles (APMs) and evaluated for their biopharmaceutical outcomes. The APMs were prepared using mPEG-b-PCL/CTAB as a copolymer-surfactant system via the liquid antisolvent precipitation (LAP) method. The design of these APMs were optimized using Box Behnken Design by taking various process/formulation based variables to achieve the desired micellar traits. The release of both the drugs from the optimized co-loaded APMs was compared in different media and displayed a remarkable sustained release profile owing to their hydrophobic interactions with the PCL core. The in vitro cytotoxicity study of co-loaded APMs on Caco-2 cells revealed 70 % cell viability in a concentration-dependent manner. The preventive effects of Gly and VA co-loaded in APMs on glucose uptake was studied in insulin-responsive human HepG2 cells treated with high glucose. The co-loading of both the drugs in optimized APMs exhibited synergistic glucose-lowering activity (p < 0.001) than raw drugs with low cytotoxicity on HepG2 cells within the test concentration. This could be attributed to an increase in the relative oral bioavailability of both the drugs in APMs i.e., 868 % for Gly and 87 % for VA respectively.

Sulfonylureas and the Risk of Ventricular Arrhythmias Among People with Type 2 Diabetes: A Systematic Review of Observational Studies

Previous studies have suggested an association between sulfonylureas and an increased risk of cardiovascular death among patients with type 2 diabetes. A potential mechanism involves sulfonylurea-induced ventricular arrhythmias (VAs). We conducted a systematic review of observational studies to determine whether the use of sulfonylureas, compared with the use of other antihyperglycemic drugs, is associated with the risk of VA (ventricular tachycardia, ventricular fibrillation, and premature ventricular complexes), cardiac arrest, and sudden cardiac death among patients with type 2 diabetes. Two independent reviewers searched MEDLINE, EMBASE, CINAHL Plus, CENTRAL, and ClinicalTrials.gov from inception to July 2021 for observational studies comparing sulfonylureas vs. other antihyperglycemic therapies or intraclass comparisons of sulfonylureas. Our systematic review included 17 studies (1,607,612 patients). Per Risk Of Bias In Non-randomized Studies of Interventions (ROBINS)-I, there were few high-quality studies (2 studies at moderate risk of bias; 4 at serious risk; and 11 at critical risk). All studies at a moderate or serious risk of bias reporting comparisons with other therapies were consistent with an increased risk of VA. Sulfonylureas were associated with a higher risk of arrhythmia vs. dipeptidyl peptidase-4 inhibitors (adjusted hazard ratio (aHR): 1.52, 95% confidence interval (CI): 1.27-1.80) and of VA vs. metformin (aHR: 1.52, 95% CI: 1.10-2.13). One moderate quality study reported inconsistent results for a composite of cardiac arrest/VA in analyses of US Medicaid claims and Optum claims data. Our systematic review suggests that, among higher-quality observational studies, sulfonylureas are associated with an increased risk of VA. However, we identified few methodologically rigorous studies, underscoring the need for additional real-world studies.

Metformin versus sulphonylureas for new onset atrial fibrillation and stroke in type 2 diabetes mellitus: a population-based study

AIMS

To gain insights on the cardiovascular effects of metformin and sulphonylurea, the present study compares the rates of incident atrial fibrillation, stroke, cardiovascular mortality and all-cause mortality between metformin and sulphonylurea users in type 2 diabetes mellitus.

METHODS

This was a retrospective population-based cohort study of type 2 diabetes mellitus patients receiving either sulphonylurea or metformin monotherapy between January 1, 2000, and December 31, 2019. The primary outcome was new-onset AF or stroke. Secondary outcomes were cardiovascular, non-cardiovascular and all-cause mortality. Propensity score matching (1:2 ratio) between sulphonylurea and metformin users was performed, based on demographics, CHA-DS-VASc score, past comorbidities and medication use. Cox regression was used to identify significant risk factors. Competing risk analysis was conducted using cause-specific and subdistribution hazard models. Sensitivity analyses using propensity score stratification, high-dimensional propensity score and inverse probability of treatment weighting were conducted. Subgroup analyses were conducted for age and gender in the matched cohort.

RESULTS

A total of 36,228 sulphonylurea users and 72,456 metformin users were included in the propensity score-matched cohort. Multivariable Cox regression showed that sulphonylurea users had higher risks of incident AF (hazard ratio [HR]: 2.89, 95% confidence interval [CI]: 2.75-3.77; P < 0.0001), stroke (HR: 3.23, 95% CI: 3.01-3.45; P < 0.0001), cardiovascular mortality (HR: 3.60, 95% CI: 2.62-4.81; P < 0.0001) and all-cause mortality (HR: 4.35, 95% CI: 3.16-4.75; P < 0.0001) compared to metformin users. Similarly, significant results were observed using cause-specific and subdistribution hazard models. Sensitivity analysis using techniques based on the propensity score also yielded similar results.

CONCLUSIONS

Sulphonylurea use was associated with higher risks of incident AF, stroke, cardiovascular mortality and all-cause mortality compared to metformin. Males and patients older than 65 years with sulphonylurea use were exposed to the highest risks.

Clinical Observation of SGLT2 Inhibitor Therapy for Cardiac Arrhythmia and Related Cardiovascular Disease in Diabetic Patients with Controlled Hypertension

Sodium-glucose transporter 2 (SGLT2) inhibitors are new glucose-lowering agents that have been proven to be beneficial for patients with cardiovascular diseases, heart failure, and sudden cardiac death. However, the possible protective effects of cardiac arrhythmia have not yet been clarified in clinical practice. In this study, we attempted to demonstrate the effects of SGLT2 inhibitors on cardiac arrhythmia by medical records from a single center. This retrospective study included patients diagnosed with type 2 diabetes mellitus (DM) and controlled hypertension who prescribed the indicated glucose-lowering agents based on medical records from 2016 to 2019 from Kaohsiung Medical University Hospital. These patients were divided into two groups. Group one patients were defined as patients with SGLT2 inhibitor therapy, and group two patients were defined as patients without SGLT2 inhibitor therapy. Baseline characteristics were collected from medical records. Univariate, multivariate, and match-paired statistical analyses were performed for the study endpoints. The primary study outcome was the incidence of cardiac arrhythmias, including atrial and ventricular arrhythmias, after SGLT2 inhibitor therapy. The secondary study outcomes were the incidence of stroke, heart failure, and myocardial infarction after SGLT2 inhibitor therapy. From the initial 62,704 medical records, a total of 9609 people who met our experimental design criteria were included. The mean follow-up period was 51.50 ± 4.23 months. Group one included 3203 patients who received SGLT2 inhibitors for treatment, and group two included 6406 patients who received non-SGLT2 inhibitors for treatment. Multivariate analysis showed that group one patients had significantly lower incidences of total cardiac arrhythmia (hazard ratio (HR): 0.58, 95% confidence interval (CI): 0.38–0.89, p = 0.013) and atrial fibrillation (HR: 0.56, 95% CI: 0.35–0.88, p = 0.013) than those of group two patients. The secondary outcome analysis showed that group one patients also had a significantly lower risk of stroke (HR: 0.48, 95% CI: 0.33–0.7; p < 0.001), heart failure (HR: 0.54, 95% CI: 0.41–0.7, p < 0.001), and myocardial infarction (HR: 0.47, 95% CI: 0.31–0.72, p < 0.001). A time-to-event analysis showed that treatment of type 2 DM patients with SGLT2 inhibitors could reduce the probability of total cardiac arrhythmia and related cardiovascular disease, such as atrial fibrillation, stroke, heart failure, or myocardial infarction, by 0.5%~0.8%. This databank analysis showed that SGLT2 inhibitor therapy reduced the incidence of total cardiac arrhythmia and atrial fibrillation in type 2 DM patients and decreased the incidence of related cardiovascular diseases, such as stroke, heart failure, and myocardial infarction. However, additional investigations are needed to confirm this hypothesis.

Characteristics of Ventricular Electrophysiological Substrates in Metabolic Mice Treated with Empagliflozin

Empagliflozin (EMPA) is a sodium–glucose transporter 2 (SGLT2) inhibitor that functions as a new-generation glucose-lowering agent and has been proven to be beneficial for patients with cardiovascular diseases. However, the possible benefits and mechanisms of its antiarrhythmic effects in cardiac tissue have not yet been reported. In this study, we elucidated the possible antiarrhythmic effects and mechanisms of EMPA treatment in cardiac tissues of metabolic syndrome (MS) mice. A total of 20 C57BL/6J mice (age: 8 weeks) were divided into four groups: (1) control group, mice fed a standard chow for 16 weeks; (2) MS group, mice fed a high-fat diet for 16 weeks; (3) EMPA group, mice fed a high-fat diet for 12 weeks and administered EMPA at 10 mg/kg daily for the following 4 weeks; and (4) glibenclamide (GLI) group, mice fed a high-fat diet for 12 weeks and administered GLI at 0.6 mg/kg daily for the following 4 weeks. All mice were sacrificed after 16 weeks of feeding. The parameters of electrocardiography (ECG), echocardiography, and the effective refractory period (ERP) of the left ventricle were recorded. The histological characteristics of cardiac tissue, including connexin (Cx) expression and fibrotic areas, were also evaluated. Compared with the MS group, the ECG QT interval in the EMPA group was significantly shorter (57.06 ± 3.43 ms vs. 50.00 ± 2.62 ms, p = 0.011). The ERP of the left ventricle was also significantly shorter in the EMPA group than that in the GLI group (20.00 ± 10.00 ms vs. 60.00 ± 10.00 ms, p = 0.001). The expression of Cx40 and Cx43 in ventricular tissue was significantly lower in the MS group than in the control group. However, the downregulation of Cx40 and Cx43 was significantly attenuated in the EMPA group compared with the MS and GLI groups. The fibrotic areas of ventricular tissue were also fewer in the EMPA group than that in the MS group. In this study, the ECG QT interval in the EMPA group was shorter than that in the MS group. Compared with the MS group, the EMPA group exhibited significant attenuation of downregulated connexin expression and significantly fewer fibrotic areas in ventricles. These results may provide evidence of possible antiarrhythmic effects of EMPA.

Sulfonylurea antidiabetics are associated with lower risk of out-of-hospital cardiac arrest: Real-world data from a population-based study

Aims

Out‐of‐hospital cardiac arrest (OHCA) mostly results from ventricular tachycardia/ventricular fibrillation (VT/VF), often triggered by acute myocardial infarction (AMI). Sulfonylurea (SU) antidiabetics can block myocardial ATP‐regulated K⁺ channels (K_ATP channels), activated during AMI, thereby modulating action potential duration (APD). We studied whether SU drugs impact on OHCA risk, and whether these effects are related to APD changes.

Methods

We conducted a population‐based case–control study in 219 VT/VF‐documented OHCA cases with diabetes and 697 non‐OHCA controls with diabetes. We studied the association of SU drugs (alone or in combination with metformin) with OHCA risk compared to metformin monotherapy, and of individual SU drugs compared to glimepiride, using multivariable logistic regression analysis. We studied the effects of these drugs on APD during simulated ischaemia using patch‐clamp studies in human induced pluripotent stem cell‐derived cardiomyocytes.

Results

Compared to metformin, use of SU drugs alone or in combination with metformin was associated with reduced OHCA risk (OR_{SUdrugs‐alone} 0.6 [95% CI 0.4–0.9], OR_{SUdrugs + metformin} 0.6 [95% CI 0.4–0.9]). We found no differences in OHCA risk between SU drug users who suffered OHCA inside or outside the context of AMI. Reduction of OHCA risk compared to glimepiride was found with gliclazide (OR_adj 0.5 [95% CI 0.3–0.9]), but not glibenclamide (OR_adj 1.3 [95% CI 0.6–2.7]); for tolbutamide, the association with reduced OHCA risk just failed to reach statistical significance (OR_adj 0.6 [95% CI 0.3–1.002]). Glibenclamide attenuated simulated ischaemia‐induced APD shortening, while the other SU drugs had no effect.

Conclusions

SU drugs were associated with reduced OHCA risk compared to metformin monotherapy, with gliclazide having a lower risk than glimepiride. The differential effects of SU drugs are not explained by differential effects on APD.

Effects of Secretome from Fat Tissues on Ion Currents of Cardiomyocyte Modulated by Sodium-Glucose Transporter 2 Inhibitor

Sodium-glucose transporter 2 (SGLT2) inhibitors were shown to decrease mortality from cardiovascular diseases in the EMPA-REG trial. However, the effects of empagliflozin (EMPA) for cardiac arrhythmia are not yet clarified. A total of 20 C57BL/6J mice were divided into four groups: (1) The control group were fed standard chow, (2) the metabolic syndrome (MS) group were fed a high-fat diet, (3) the empagliflozin (EMPA) group were fed a high-fat diet and empagliflozin 10 mg/kg daily, and (4) the glibenclamide (GLI) group were fed a high-fat diet and glibenclamide 0.6 mg/kg daily. All mice were sacrificed after 16 weeks of feeding. H9c2 cells were treated with adipocytokines from the pericardial and peripheral fat from the study groups. The delayed-rectifier potassium current (I_K) and L-type calcium channel current (I_Ca,L) were measured by the whole-cell patch clamp techniques. Adipocytokines from the peripheral and pericardial fat tissues of mice with MS could decrease the I_K and increase the I_Ca,L of cardiomyocytes. After treating adipocytokines from pericardial fat, the I_K in the EMPA and GLI groups were significantly higher than that in the MS group. The I_K of the EMPA group was also significantly higher than the GLI group. The I_Ca,L of the EMPA and GLI groups were significantly decreased overload compared with that of the MS group. However, there was no significant difference of I_K and I_Ca,L among study groups after treating adipocytokines from peripheral fat. Adipocytokines from pericardial fat but not peripheral fat tissues after EMPA therapy attenuated the effects of I_K decreasing and I_Ca,L increasing in the MS cardiomyocytes, which may contribute to anti-arrhythmic mechanisms of sodium-glucose transporter 2 (SGLT2) inhibitors.

Risk of sudden cardiac arrest and ventricular arrhythmia with sulfonylureas: An experience with conceptual replication in two independent populations

Sulfonylureas are commonly used to treat type 2 diabetes mellitus. Despite awareness of their effects on cardiac physiology, a knowledge gap exists regarding their effects on cardiovascular events in real-world populations. Prior studies reported sulfonylurea-associated cardiovascular death but not serious arrhythmogenic endpoints like sudden cardiac arrest (SCA) or ventricular arrhythmia (VA). We assessed the comparative real-world risk of SCA/VA among users of second-generation sulfonylureas: glimepiride, glyburide, and glipizide. We conducted two incident user cohort studies using five-state Medicaid claims (1999–2012) and Optum Clinformatics commercial claims (2000–2016). Outcomes were SCA/VA events precipitating hospital presentation. We used Cox proportional hazards models, adjusted for high-dimensional propensity scores, to generate adjusted hazard ratios (aHR). We identified 624,406 and 491,940 sulfonylurea users, and 714 and 385 SCA/VA events, in Medicaid and Optum, respectively. Dataset-specific associations with SCA/VA for both glimepiride and glyburide (vs. glipizide) were on opposite sides of and could not exclude the null (glimepiride: aHR_Medicaid 1.17, 95% CI 0.96–1.42; aHR_Optum 0.84, 0.65–1.08; glyburide: aHR_Medicaid 0.87, 0.74–1.03; aHR_Optum 1.11, 0.86–1.42). Database differences in data availability, populations, and documentation completeness may have contributed to the incongruous results. Emphasis should be placed on assessing potential causes of discrepancies between conflicting studies evaluating the same research question.

Synthesis and evaluation of novel peptidomimetics bearing p-aminobenzoic acid moiety as potential antidiabetic agents

Aim: Search for a new class of potential antidiabetic agents. Methodology: A series of novel peptidomimetics bearing the p-aminobenzoic acid moiety (TM3-TM6) were designed and synthesized. For all synthetic target molecules, the peroxisome proliferator response element (PPRE) activated activities have been evaluated and the toxicity were computed. Results & discussion: 46 new p-aminobenzoic acid derivatives have been characterized by ¹H NMR, ¹³C NMR and high-resolution mass spectrometry (HRMS). The results of in vitro PPRE-activated activity, molecular docking study and toxicity prediction revealed that these compounds had potential antidiabetic activities and low toxicity. In particular compound 3b had up to 87% PPRE-activated activity compared with pioglitazone. This discovery may provide new insights for finding novel PPRE lead compound.

The risk of sudden cardiac arrest and ventricular arrhythmia with rosiglitazone versus pioglitazone: real-world evidence on thiazolidinedione safety

BACKGROUND

The low cost of thiazolidinediones makes them a potentially valuable therapeutic option for the > 300 million economically disadvantaged persons worldwide with type 2 diabetes mellitus. Differential selectivity of thiazolidinediones for peroxisome proliferator-activated receptors in the myocardium may lead to disparate arrhythmogenic effects. We examined real-world effects of thiazolidinediones on outpatient-originating sudden cardiac arrest (SCA) and ventricular arrhythmia (VA).

METHODS

We conducted population-based high-dimensional propensity score-matched cohort studies in five Medicaid programs (California, Florida, New York, Ohio, Pennsylvania | 1999-2012) and a commercial health insurance plan (Optum Clinformatics | 2000-2016). We defined exposure based on incident rosiglitazone or pioglitazone dispensings; the latter served as an active comparator. We controlled for confounding by matching exposure groups on propensity score, informed by baseline covariates identified via a data adaptive approach. We ascertained SCA/VA outcomes precipitating hospital presentation using a validated, diagnosis-based algorithm. We generated marginal hazard ratios (HRs) via Cox proportional hazards regression that accounted for clustering within matched pairs. We prespecified Medicaid and Optum findings as primary and secondary, respectively; the latter served as a conceptual replication dataset.

RESULTS

The adjusted HR for SCA/VA among rosiglitazone (vs. pioglitazone) users was 0.91 (0.75-1.10) in Medicaid and 0.88 (0.61-1.28) in Optum. Among Medicaid but not Optum enrollees, we found treatment effect heterogeneity by sex (adjusted HRs = 0.71 [0.54-0.93] and 1.16 [0.89-1.52] in men and women respectively, interaction term p-value = 0.01).

CONCLUSIONS

Rosiglitazone and pioglitazone appear to be associated with similar risks of SCA/VA.

Comparative cardiovascular and hypoglycaemic safety of glimepiride in type 2 diabetes: A population-based cohort study

AIM

To assess the incidence of cardiovascular and hypoglycaemic adverse events associated with glimepiride compared with other second-generation sulphonylureas among patients with type 2 diabetes in a real-world clinical setting.

MATERIALS AND METHODS

We identified all sulphonylurea initiators between 1998 and 2017 in the UK Clinical Practice Research Datalink. Using a prevalent new-user design, glimepiride initiators were matched 1:4 with initiators of other second-generation sulphonylureas on calendar time, prior sulphonylurea use, and time-conditional high-dimensional propensity score. Cox proportional hazards models yielded adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for myocardial infarction, ischaemic stroke, severe hypoglycaemia, cardiovascular death, and all-cause mortality.

RESULTS

Among 66 032 sulphonylurea new users, 6438 initiated glimepiride and were matched to up to 20 582 initiators of other second-generation sulphonylureas. During a mean follow-up of 1.3 years, glimepiride was associated with a similar incidence of myocardial infarction (HR 0.99, 95% CI 0.75-1.30) and ischaemic stroke (HR 0.96, 95% CI 0.72-1.27) compared with other second-generation sulphonylureas, while there was a non-significant trend towards a higher incidence of severe hypoglycaemia (HR 1.24, 95% CI 0.92-1.68). Glimepiride was also associated with a lower incidence of all-cause mortality (HR 0.77, 95% CI 0.67-0.89), and a non-significant but similar trend for cardiovascular death (HR 0.83, 95% CI 0.65-1.05).

CONCLUSIONS

Glimepiride was associated with a lower incidence of all-cause mortality compared with other second-generation sulphonylureas.

Temperature and pH sensitive composite for rapid and effective removal of sulfonylurea herbicides in aqueous solution

Excessive pesticide residues in the environment have caused more and more serious social problems. In this article, the polymer materials and graphene oxide were smoothly grafted together through surface-initiated atom-transfer radical polymerization. A temperature and pH dual-sensitive adsorbent was successfully obtained, which was used for the removal of six sulfonylurea herbicides in the aquatic environment. Experiment results showed that the adsorbent could efficiently remove the tested pesticides in aqueous solution rapidly (only 1 min). The adsorption process was in consist with the pseudo-second-order kinetics equation and Freundlich model, and the thermodynamic parameters were also calculated. Furthermore, the mechanism for removal performance was judged as n-π, π-π, hydrogen bonding, hydrophobic and electrostatic interaction verdict. Exhilaratingly, the material showed no significant toxicity to Daphnia magna on risk assessment.

Methylome-wide association study provides evidence of particulate matter air pollution-associated DNA methylation

BACKGROUND

DNA methylation (DNAm) may contribute to processes that underlie associations between air pollution and poor health. Therefore, our objective was to evaluate associations between DNAm and ambient concentrations of particulate matter (PM) ≤2.5, ≤10, and 2.5-10 μm in diameter (PM2.5; PM10; PM2.5-10).

METHODS

We conducted a methylome-wide association study among twelve cohort- and race/ethnicity-stratified subpopulations from the Women's Health Initiative and the Atherosclerosis Risk in Communities study (n = 8397; mean age: 61.5 years; 83% female; 45% African American; 9% Hispanic/Latino American). We averaged geocoded address-specific estimates of daily and monthly mean PM concentrations over 2, 7, 28, and 365 days and 1 and 12 months before exams at which we measured leukocyte DNAm in whole blood. We estimated subpopulation-specific, DNAm-PM associations at approximately 485,000 Cytosine-phosphate-Guanine (CpG) sites in multi-level, linear, mixed-effects models. We combined subpopulation- and site-specific estimates in fixed-effects, inverse variance-weighted meta-analyses, then for associations that exceeded methylome-wide significance and were not heterogeneous across subpopulations (P < 1.0 × 10-7; PCochran's Q > 0.10), we characterized associations using publicly accessible genomic databases and attempted replication in the Cooperative Health Research in the Region of Augsburg (KORA) study.

RESULTS

Analyses identified significant DNAm-PM associations at three CpG sites. Twenty-eight-day mean PM10 was positively associated with DNAm at cg19004594 (chromosome 20; MATN4; P = 3.33 × 10-8). One-month mean PM10 and PM2.5-10 were positively associated with DNAm at cg24102420 (chromosome 10; ARPP21; P = 5.84 × 10-8) and inversely associated with DNAm at cg12124767 (chromosome 7; CFTR; P = 9.86 × 10-8). The PM-sensitive CpG sites mapped to neurological, pulmonary, endocrine, and cardiovascular disease-related genes, but DNAm at those sites was not associated with gene expression in blood cells and did not replicate in KORA.

CONCLUSIONS

Ambient PM concentrations were associated with DNAm at genomic regions potentially related to poor health among racially, ethnically and environmentally diverse populations of U.S. women and men. Further investigation is warranted to uncover mechanisms through which PM-induced epigenomic changes may cause disease.

Functional protection against cardiac diseases depends on ATP-sensitive potassium channels

ATP-sensitive potassium channels (KATP) channels are widely distributed in various tissues, including pancreatic beta cells, muscle tissue and brain tissue. KATP channels play an important role in cardioprotection in physiological/pathological situations. KATP channels are inhibited by an increase in the intracellular ATP concentration and are stimulated by an increase in the intracellular MgADP concentration. Activation of KATP channels decreases ischaemia/reperfusion injury, protects cardiomyocytes from heart failure, and reduces the occurrence of arrhythmias. KATP channels are involved in various signalling pathways, and their participation in protective processes is regulated by endogenous signalling molecules, such as nitric oxide and hydrogen sulphide. KATP channels may act as a new drug target to fight against cardiovascular disease in the development of related drugs in the future. This review highlights the potential mechanisms correlated with the protective role of KATP channels and their therapeutic value in cardiovascular diseases.

Glibenclamide Prevents Hypoglycemia-Induced Fatal Cardiac Arrhythmias in Rats

Sulfonylureas increase the incidence of severe hypoglycemia in people with type 2 diabetes and might increase the risk of sudden cardiac death. Sulfonylureas stimulate insulin secretion by closing pancreatic ATP-sensitive potassium ion (KATP) channels. To investigate the role of KATP channel modulators on cardiac arrhythmias and mortality in the setting of severe hypoglycemia, adult Sprague-Dawley rats underwent hyperinsulinemic (0.2 U/kg/min) severe hypoglycemic (10 to 15 mg/dL) clamps with continuous electrocardiography. The rats were randomized for treatment with intravenous vehicle (VEH), the sulfonylurea glibenclamide (GLIB; KATP channel blocker; 5 mg/kg/h), or diazoxide (DIAZ; KATP channel opener; 5 mg/kg/h). The results demonstrated that GLIB completely prevented first-degree heart block compared with VEH (0.18 ± 0.09/min) and DIAZ (0.2 ± 0.05/min). Second-degree heart block was significantly reduced with GLIB (0.12 ± 0.1/min) compared with VEH (0.6 ± 0.2/min) and DIAZ (6.9 ± 3/min). The incidence of third-degree heart block was completely prevented by GLIB compared with VEH (67%) and DIAZ (87.5%). Hypoglycemia-induced mortality was completely prevented by GLIB compared with VEH (60%) and DIAZ (82%). In conclusion, although GLIB increases the risk of hypoglycemia by increasing insulin secretion, these results have demonstrated a paradoxical protective role of GLIB against severe hypoglycemia-induced fatal cardiac arrhythmias.

Comparative Safety of Sulfonylureas and the Risk of Sudden Cardiac Arrest and Ventricular Arrhythmia

OBJECTIVE

To examine the association between individual antidiabetic sulfonylureas and outpatient-originating sudden cardiac arrest and ventricular arrhythmia (SCA/VA).

RESEARCH DESIGN AND METHODS

We conducted a retrospective cohort study using 1999-2010 U.S. Medicaid claims from five large states. Exposures were determined by incident use of glyburide, glimepiride, or glipizide. Glipizide served as the reference exposure, as its effects are believed to be highly pancreas specific. Outcomes were ascertained by a validated ICD-9-based algorithm indicative of SCA/VA (positive predictive value ∼85%). Potential confounding was addressed by adjustment for multinomial high-dimensional propensity scores included as continuous variables in a Cox proportional hazards model.

RESULTS

Of sulfonylurea users under study (N = 519,272), 60.3% were female and 34.9% non-Hispanic Caucasian, and the median age was 58.0 years. In 176,889 person-years of sulfonylurea exposure, we identified 632 SCA/VA events (50.5% were immediately fatal) for a crude incidence rate of 3.6 per 1,000 person-years. Compared with glipizide, propensity score-adjusted hazard ratios for SCA/VA were 0.82 (95% CI 0.69-0.98) for glyburide and 1.10 (0.89-1.36) for glimepiride. Numerous secondary analyses showed a very similar effect estimate for glyburide; yet, not all CIs excluded the null.

CONCLUSIONS

Glyburide may be associated with a lower risk of SCA/VA than glipizide, consistent with a very small clinical trial suggesting that glyburide may reduce ventricular tachycardia and isolated ventricular premature complexes. This potential benefit must be contextualized by considering putative effects of different sulfonylureas on other cardiovascular end points, cerebrovascular end points, all-cause death, and hypoglycemia.

Evaluating the Diabetes-Cardiology interface: a glimpse into the diabetes management of cardiology inpatients in western Sydney's 'diabetes hotspot' and the establishment of a novel model of care

BACKGROUND

Approximately two-thirds of individuals presenting to emergency departments in Western Sydney have glucose dysregulation, accelerating their risk of cardiovascular disease (CVD). We evaluated the prevalence and management of type 2 diabetes (T2D) in cardiology inpatients in Western Sydney. A novel model of care between diabetes and cardiology specialist hospital teams (joint specialist case conferencing, JSCC) is described herein and aimed at aligning clinical services and upskilling both teams in the management of the cardiology inpatient with comorbid T2D.

METHODS

Cardiology inpatients at Blacktown-Mount Druitt Hospital were audited during a 1-month period.

RESULTS

233 patients were included, mean age 64 ± 16 years, 60% were male, 27% overweight and 35% obese. Known T2D comprised 36% (n = 84), whereas 6% (n = 15) had a new diagnosis of T2D, of which none of the latter were referred for inpatient/outpatient diabetes review. Approximately, 27% (n = 23) and 7% (n = 6) of known diabetes patients suffered hyper- and hypoglycaemia, respectively, and 51% (n = 43) had sub-optimally controlled T2D (i.e. HbA1c > 7.0%); over half (51%, n = 51) had coronary artery disease. Only two patients were treated with an SGLT2 inhibitor and no patients were on glucagon like peptide-1 receptor analogues. The majority were managed with metformin (62%) and therapies with high hypoglycaemic potential (e.g., sulfonylureas (29%)) and in those patients treated with insulin, premixed insulin was used in the majority of cases (47%).

CONCLUSIONS

Undiagnosed T2D is prevalent and neglected in cardiology inpatients. Few patients with comorbid T2D and CVD were managed with therapies of proven cardiac and mortality benefit. Novel models of care may be beneficial in this high-risk group of patients and discussed herein is the establishment of the diabetes-cardiology JSCC service delivery model which has been established at our institution.

Sorption potential of alkaline treated straw and a soil for sulfonylurea herbicide removal from aqueous solutions: An environmental management strategy

The adsorption potential of alkaline treated straw (wheat and corn) in mixture with soil, has been investigated for the removal of sulfonylurea molecules from an aqueous solutions. The surface characteristics were investigated by scanning electron microscopy and Fourier Transform Infrared - FTIR, while the adsorbent capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry. Surface analysis of alkaline treated straw samples by scanning electron microscopy - SEM showed the increasing of the surface roughness improving their functional surface activity. An increase (337.22 mg g^-1) of adsorption capacity of sulfonylurea molecules was obtained for all studied straw. The Langmuir isotherm model was the best model for the mathematical description of the adsorption process indicating the forming of a surface sorption monolayer with a finite number of identical sites. The kinetics of sulfonylurea herbicide followed the pseudo-second order mechanism corresponding to strong chemical interactions. The results sustained that the alkaline treated straw have biosorption characteristics, being suitable adsorbent materials.