Impact of glucose-lowering drugs on cardiovascular disease in type 2 diabetes

Reliability of Metformin's protective effects against doxorubicin-induced cardiotoxicity: a meta-analysis of animal studies

Background

The protective effects of metformin (Met) against doxorubicin (Dox)-induced cardiotoxicity via potential hypotheses of mechanisms of action with unknown reliability and credibility.

Objectives

This study aimed to investigate the protective effects of Met against Dox-induced cardiotoxicity and the underlying mechanisms of action, as well as examine their reliability and credibility.

Methods

A comprehensive search was conducted within the PubMed, Embase, Web of Science, Science Direct, Scopus, and CNKI databases from inception to 31 December 2023. Animal experiments evaluating the efficacy of Met against Dox-induced cardiotoxicity were included in this study. The primary efficacy outcomes were markers of myocardial injury. Effect size was measured using the standardized mean difference for continuous variables. Data were pooled using a random-effects model in the Stata 18 statistical software package.

Results

Twenty-one studies involving 203-208 animals treated with Dox and 271-276 animals treated with Dox and Met were included in this analysis. Quality assessment revealed high-quality scores. Pooled results favored Met treatment based on the serum lactate dehydrogenase (LDH), creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTnI), and aspartate aminotransferase levels. Sensitivity analysis using the leave-one-out method demonstrated stable results. Funnel plots, Egger's test, and Begg's test confirmed potential publication bias. The oxidative stress hypothesis has been investigated extensively based on abundant evidence.

Conclusion

Met is effective and safe for protecting against Dox-induced cardiotoxicity, thus making it an appropriate drug for clinical investigation. The oxidative stress hypothesis of mechanism of action is well established with highest reliability and credibility.

Real time imaging of cell-permeable nanoreactor with SERS for insight into cellular processes

Intracellular glucose detection is crucial due to its pivotal role in metabolism and various physiological processes. Precise glucose monitoring holds significance in diabetes management, metabolic studies, and biotechnological applications. In this study, we developed an innovative and expedient cell-permeable nanoreactor for intracellular glucose based on surface-enhanced Raman scattering (SERS). The nanoreactor was designed with gold nanoparticles (AuNPs), which were engineered with glucose oxide (GOx) and a H2O2-responsive Raman reporter 2-mercaptohydroquinone (2-MHQ). The interaction between 2-MHQ and H2O2 generated by glucose and GOx could simultaneously induce the appearance in the peak at 985 cm-1. Our results showed excellent performance in detecting glucose within the concentration range from 0.1 μM to 10 mM, with a low detection limitation of 14.72 nM. In addition, the glucose distribution in single HeLa cells was evaluated by real time SERS mapping. By combining noble metal particles and natural oxidases, the nanoreactor possesses both Raman activity and enzymatic functionality, thus enables sensitive glucose detection and facilitates imaging at a single cell level, which offers an insightful monitoring of cellular processes.

Association of perioperative glucose profiles assessed by continuous glucose monitoring (CGM) with prognosis in Chinese patients with non-ST-elevation acute coronary syndrome: a cohort study protocol

INTRODUCTION

Non-ST-elevation acute coronary syndrome (NSTE-ACS) remains a significant clinical concern, accounting for over 70% of acute coronary syndrome cases. One well-established risk factor for NSTE-ACS is abnormal glucose metabolism, which is associated with a poor prognosis postpercutaneous coronary intervention. Effective monitoring of blood glucose is crucial in diabetes care, as it helps identify glucose metabolic imbalances, thereby guiding therapeutic strategies and assessing treatment efficacy. Continuous glucose monitoring (CGM) provides comprehensive glucose profiles. Therefore, the study aims to use CGM to track perioperative glucose variations in NSTE-ACS patients and to determine its prognostic implications.

METHODS AND ANALYSIS

This is a multicentre, prospective observational study in a sample of patients (aged >18 years) with NSTE-ACS. A total of 1200 eligible patients will be recruited within 1 year at 6 sites in China. The primary composite endpoint will be determined as major adverse cardiovascular events (MACE) at 3 years. MACE includes all-cause mortality, non-fatal myocardial infarction, non-fatal stroke and target vessel revascularisation. Employing the CGM system, glucose levels will be continuously monitored throughout the perioperative phase. Prespecified cardiovascular analyses included analyses of the components of this composite and outcomes according to CGM-derived glucometrics at baseline.

ETHICS AND DISSEMINATION

This study has received approval from the Medical Research Ethics Committee of The First Affiliated Hospital of the University of Science and Technology of China (No. 2022KY357) and will adhere to the moral, ethical and scientific principles outlined in the Declaration of Helsinki. All participants will provide written informed consent prior to any study-related procedures. Findings from the study will be shared at conferences and published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

ChiCT2300069663.

Glucocorticoid-Induced Hyperglycemia: A Neglected Problem

Glucocorticoids provide a potent therapeutic response and are widely used to treat a variety of diseases, including coronavirus disease 2019 (COVID-19) infection. However, the issue of glucocorticoid-induced hyperglycemia (GIH), which is observed in over one-third of patients treated with glucocorticoids, is often neglected. To improve the clinical course and prognosis of diseases that necessitate glucocorticoid therapy, proper management of GIH is essential. The key pathophysiology of GIH includes systemic insulin resistance, which exacerbates hepatic steatosis and visceral obesity, as well as proteolysis and lipolysis of muscle and adipose tissue, coupled with β-cell dysfunction. For patients on glucocorticoid therapy, risk stratification should be conducted through a detailed baseline evaluation, and frequent glucose monitoring is recommended to detect the onset of GIH, particularly in high-risk individuals. Patients with confirmed GIH who require treatment should follow an insulin-centered regimen that varies depending on whether they are inpatients or outpatients, as well as the type and dosage of glucocorticoid used. The ideal strategy to maintain normoglycemia while preventing hypoglycemia is to combine basal-bolus insulin and correction doses with a continuous glucose monitoring system. This review focuses on the current understanding and latest evidence concerning GIH, incorporating insights gained from the COVID-19 pandemic.

Effect of Metformin on Oxidative Stress and Left Ventricular Geometry in Nondiabetic Heart Failure Patients: A Randomized Controlled Trial

Introduction: There is an increasing interest in using metformin in cardiovascular diseases and its potential new roles. Only two randomized controlled trials investigated the effect of metformin in nondiabetic heart failure (HF) patients. However, none of these studies assess the role of metformin in reducing oxidative stress. We hypothesized that metformin might improve oxidative stress and left ventricular remodeling in nondiabetic HF patients with reduced ejection fraction (HFrEF). Methods and Methods: Seventy HFrEF patients (EF 37% ± 8%; median age 66 years) were randomized to metformin (n = 35) or standard of care (SOC) for HF (n = 35) for 6 months in addition to standard therapy. Outcomes included the difference in the change (Δ) in total antioxidant capacity (TAC) and malondialdehyde (MDA), both assessed colorimetrically and left ventricular mass index (LVMI) assessed through transthoracic echocardiography. Results: Compared with the SOC, metformin treatment increased TAC [Δ = 0.12 mmol/L, confidence intervals (95% CIs): 0.03-0.21; P = 0.007]. TAC increased significantly only in the metformin group (0.90 ± 0.08 mmol/L at baseline vs. 1.04 ± 0.99 mmol/L at 6 months, P < 0.05). Metformin therapy preserved LVMI (Δ = -23 g/m2, 95% CI: -42.91 to -4.92; P = 0.014) and reduced fasting plasma glucose (Δ = -6.16, 95% CI: -12.31 to -0.02, P = 0.047) compared with the SOC. Results did not change after adjusting for baseline values. Changes in MDA left ventricular ejection fraction (LVEF) and blood pressure were not significantly different between groups. Conclusion: Metformin treatment in HF patients with reduced LVEF improved TAC and prevented the increase in LVMI compared with the SOC. These effects of metformin warrant further research in HF patients without diabetes to explore the potential benefits of metformin. Trial Registration Number: This protocol was registered in ClinicalTrials.gov under the number NCT05177588.

Teneligliptin alleviates diabetes-related cognitive impairment by inhibiting the endoplasmic reticulum (ER) stress and NLRP3 inflammasome in mice

Diabetes mellitus (DM) significantly influences the normal health of patients with its severe complications, including diabetes-related cognitive impairment (CI). Recently, neuroinflammation and oxidative stress (OS) have been reported to participate in the pathogenesis of diabetes-related CI. Teneligliptin, an inhibitor of DDP-IV, was developed for treating DM and is claimed with promising effects against inflammation. Herein, in the current study, we examined the potential therapeutic function of Teneligliptin against diabetes-related CI. Db/m or diabetic mice were orally administered with teneligliptin (60 mg/kg/day) for 10 weeks. Elevated levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C), increased escape latency, declined time in the platform quadrant and decreased number of platform crossings in the Morris water maze test, reduced freezing index in the fear conditioning test, and lessened time spent in the novel arm and percentage of alterations in the Y-maze test were observed in diabetic mice, all of which were sharply improved by teneligliptin. Furthermore, increased levels of inflammatory cytokines and activated OS state were observed in the hippocampus of diabetic mice, which were markedly repressed by Teneligliptin. Lastly, the activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) signaling and the endoplasmic reticulum (ER) stress pathway in the hippocampus of diabetic mice were notably inhibited by teneligliptin. Collectively, teneligliptin mitigated diabetes-related CI by repressing the ER stress and NLRP3 inflammasome in diabetic mice.

N6-methyladenosine (m6A) methylation in kidney diseases: Mechanisms and therapeutic potential

The N6-methyladenosine (m6A) modification is regulated by methylases, commonly referred to as "writers," and demethylases, known as "erasers," leading to a dynamic and reversible process. Changes in m6A levels have been implicated in a wide range of cellular processes, including nuclear RNA export, mRNA metabolism, protein translation, and RNA splicing, establishing a strong correlation with various diseases. Both physiologically and pathologically, m6A methylation plays a critical role in the initiation and progression of kidney disease. The methylation of m6A may also facilitate the early diagnosis and treatment of kidney diseases, according to accumulating research. This review aims to provide a comprehensive overview of the potential role and mechanism of m6A methylation in kidney diseases, as well as its potential application in the treatment of such diseases. There will be a thorough examination of m6A methylation mechanisms, paying particular attention to the interplay between m6A writers, m6A erasers, and m6A readers. Furthermore, this paper will elucidate the interplay between various kidney diseases and m6A methylation, summarize the expression patterns of m6A in pathological kidney tissues, and discuss the potential therapeutic benefits of targeting m6A in the context of kidney diseases.

Elevated remnant cholesterol and atherosclerotic cardiovascular disease in diabetes: a population-based prospective cohort study

AIMS/HYPOTHESIS

Elevated remnant cholesterol is observationally and causally associated with increased risk of atherosclerotic cardiovascular disease (ASCVD) in the general population. This association is not well studied in individuals with diabetes, who are often included in clinical trials of remnant cholesterol-lowering therapy. We tested the hypothesis that elevated remnant cholesterol is associated with increased risk of ASCVD in individuals with diabetes. We also explored the fraction of excess risk conferred by diabetes which can be explained by elevated remnant cholesterol.

METHODS

We included 4569 white Danish individuals with diabetes (58% statin users) nested within the Copenhagen General Population Study (2003-2015). The ASCVDs peripheral artery disease, myocardial infarction and ischaemic stroke were extracted from national Danish health registries without losses to follow-up. Remnant cholesterol was calculated from a standard lipid profile.

RESULTS

During up to 15 years of follow-up, 236 individuals were diagnosed with peripheral artery disease, 234 with myocardial infarction, 226 with ischaemic stroke and 498 with any ASCVD. Multivariable adjusted HR (95% CI) per doubling of remnant cholesterol was 1.6 (1.1, 2.3; p=0.01) for peripheral artery disease, 1.8 (1.2, 2.5; p=0.002) for myocardial infarction, 1.5 (1.0, 2.1; p=0.04) for ischaemic stroke, and 1.6 (1.2, 2.0; p=0.0003) for any ASCVD. Excess risk conferred by diabetes was 2.5-fold for peripheral artery disease, 1.6-fold for myocardial infarction, 1.4-fold for ischaemic stroke and 1.6-fold for any ASCVD. Excess risk explained by elevated remnant cholesterol and low-grade inflammation was 14% and 8% for peripheral artery disease, 26% and 16% for myocardial infarction, 34% and 34% for ischaemic stroke, and 24% and 18% for any ASCVD, respectively. LDL-cholesterol did not explain excess risk, as it was not higher in individuals with diabetes. We also explored the fraction of excess risk conferred by diabetes which can be explained by elevated remnant cholesterol.

CONCLUSIONS/INTERPRETATION

Elevated remnant cholesterol was associated with increased risk of ASCVD in individuals with diabetes. Remnant cholesterol and low-grade inflammation explained substantial excess risk of ASCVD conferred by diabetes. Whether remnant cholesterol should be used as a treatment target remains to be determined in randomised controlled trials.

Treating the Side Effects of Exogenous Glucocorticoids; Can We Separate the Good From the Bad?

It is estimated that 2% to 3% of the population are currently prescribed systemic or topical glucocorticoid treatment. The potent anti-inflammatory action of glucocorticoids to deliver therapeutic benefit is not in doubt. However, the side effects associated with their use, including central weight gain, hypertension, insulin resistance, type 2 diabetes (T2D), and osteoporosis, often collectively termed iatrogenic Cushing's syndrome, are associated with a significant health and economic burden. The precise cellular mechanisms underpinning the differential action of glucocorticoids to drive the desirable and undesirable effects are still not completely understood. Faced with the unmet clinical need to limit glucocorticoid-induced adverse effects alongside ensuring the preservation of anti-inflammatory actions, several strategies have been pursued. The coprescription of existing licensed drugs to treat incident adverse effects can be effective, but data examining the prevention of adverse effects are limited. Novel selective glucocorticoid receptor agonists and selective glucocorticoid receptor modulators have been designed that aim to specifically and selectively activate anti-inflammatory responses based upon their interaction with the glucocorticoid receptor. Several of these compounds are currently in clinical trials to evaluate their efficacy. More recently, strategies exploiting tissue-specific glucocorticoid metabolism through the isoforms of 11β-hydroxysteroid dehydrogenase has shown early potential, although data from clinical trials are limited. The aim of any treatment is to maximize benefit while minimizing risk, and within this review we define the adverse effect profile associated with glucocorticoid use and evaluate current and developing strategies that aim to limit side effects but preserve desirable therapeutic efficacy.

Helical-Like Assembly of Nateglinide as Coating for Oral Delivery of Insulin and Their Synergistic Prevention of Diabetes Mellitus

Oral delivery of antidiabetic active components promises to free millions of people from daily suffering who require routine injections. However, oral insulin (Ins) and other short-acting compounds such as nateglinide (NG) in harsh gastrointestinal tract still face great challenging, including low bioavailability, and rapid elimination. In this study, inspired by the self-assembly of phenylalanine-based peptides in nature, it is showed that NG a small phenylalanine derivative, assembles into left-handed helical nanofibers in the presence of Ca2+ . These helical NG nanofibers functioned as a coating layer on the surface of Ca2+ -linked alginate (Alg) microgels for the effective encapsulation of Ins. As expected, the sustained release and prolonged circulation of Ins and NG from the Ins-loading Alg/NG microgels (Ins@Alg/NG) in the intestinal tract synergistically maintain a relatively normal blood glucose level in streptozotocin-induced diabetic mice after oral administration of Ins@Alg/NG. This further confirms that Ins@Alg/NG ameliorated Ins resistance mainly through activating Insreceptor substrate 1 (IRS1), protein kinase B (AKT), and AMP-activated protein kinase (AMPK), as well as by repressing glycogen synthase kinase-3β (GSK-3β). The strategy of using the assembly of NG as a coating achieves the oral delivery of insulin and showcases a potential for the treatment of diabetes.

Long-term quality-of-care score for predicting the occurrence of acute myocardial infarction in patients with type 2 diabetes mellitus

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death globally, and diabetes mellitus (DM) is a well-established risk factor. Among the risk factors for CVD, DM is a major modifiable factor. In the fatal CVD outcomes, acute myocardial infarction (AMI) is the most common cause of death.

AIM

To develop a long-term quality-of-care score for predicting the occurrence of AMI among patients with type 2 DM on the basis of the hypothesis that good quality of care can reduce the risk of AMI in patients with DM.

METHODS

Using Taiwan’s Longitudinal Cohort of Diabetes Patient Database and the medical charts of a medical center, we identified incident patients diagnosed with type 2 DM from 1999 to 2003 and followed them until 2011. We constructed a summary quality-of-care score (with values ranging from 0 to 8) with process indicators (frequencies of HbA_1c and lipid profile testing and urine, foot and retinal examinations), intermediate outcome indicators (low-density lipoprotein, blood pressure and HbA_1c), and co-morbidity of hypertension. The associations between the score and the incidence of AMI were evaluated using Cox regression models.

RESULTS

A total of 7351 patients who had sufficient information to calculate the score were enrolled. In comparison with participants who had scores ≤ 1, those with scores between 2 and 4 had a lower risk of developing AMI [adjusted hazard ratio (AHR) = 0.71; 95% confidence interval (95%CI): 0.55-0.90], and those with scores ≥ 5 had an even lower risk (AHR = 0.37; 95%CI: 0.21-0.66).

CONCLUSION

Good quality of care can reduce the risk of AMI in patients with type 2 DM. The quality-of-care score developed in this study had a significant association with the risk of AMI and thus can be applied to guiding the care for these patients.

Ultrasound Stimulation Potentiates Management of Diabetic Hyperglycemia

OBJECTIVE

Glucose homeostasis is the only way to manage diabetic progression as all medications used do not cure diabetes. This study was aimed at verifying the feasibility of lowering glucose with non-invasive ultrasonic stimulation.

METHODS

The ultrasonic device was homemade and controlled via a mobile application on the smartphone. Diabetes was induced in Sprague-Dawley rats through high-fat diets followed by streptozotocin injection. The treated acupoint CV12 was at the middle of the xiphoid and umbilicus of the diabetic rats. Parameters of ultrasonic stimulation were an operating frequency of 1 MHz, pulse repetition frequency of 15 Hz, duty cycle of 10% and sonication time of 30 min for a single treatment.

DISCUSSION

The diabetic rats exhibited a significant decrease of 11.5% ± 3.6% in blood glucose in 5 min of ultrasonic stimulation (p < 0.001). After the single treatment on the first day, third day and fifth day in the first week, the treated diabetic rats had a significantly small area under the curve of the glucose tolerance test (p < 0.05) compared with the untreated diabetic rats in the sixth week. Hematological analyses indicated that the serum concentrations of β-endorphin were significantly increased by 58% ± 71.9% (p < 0.05) and the insulin level was increased by 56% ± 88.2% (p = 0.15) without statistical significance after a single treatment.

CONCLUSION

Therefore, non-invasive ultrasound stimulation at an appropriate dose can produce a hypoglycemic effect and improve glucose tolerance for glucose homeostasis and may play a role as adjuvant therapy with diabetic medications in the future.

Reflections on the state of diabetes research and prospects for treatment

Research on the etiology and treatment of diabetes has made substantial progress. As a result, several new classes of anti-diabetic drugs have been introduced in clinical practice. Nonetheless, the number of patients achieving glycemic control targets has not increased for the past 20 years. Two areas of unmet medical need are the restoration of insulin sensitivity and the reversal of pancreatic beta cell failure. In this review, we integrate research advances in transcriptional regulation of insulin action and pathophysiology of beta cell dedifferentiation with their potential impact on prospects of a durable "cure" for patients suffering from type 2 diabetes.

[Antihyperglycemic treatment guidelines for diabetes mellitus type 2 (Update 2023)]

Hyperglycemia significantly contributes to complications in patients with diabetes mellitus. While lifestyle interventions remain cornerstones of disease prevention and treatment, most patients with type 2 diabetes will eventually require pharmacotherapy for glycemic control. The definition of individual targets regarding optimal therapeutic efficacy and safety as well as cardiovascular effects is of great importance. In this guideline we present the most current evidence-based best clinical practice data for healthcare professionals.

Changes of Guidelines in the Management of Obese Patients With Diabetes in the Metabolic Surgery Perspective

Recently, metabolic surgery was recommended for patients with a BMI of 30 or higher and 27.5 or higher for Asians, as evidence level A. Until 2008, bariatric surgery was not introduced for the treatment of diabetes. Bariatric surgery was first recommended for adults with body mass index ≥35 kg/m² and type 2 diabetes in the American Diabetes Association (ADA) guidelines as evidence level B in 2009. In 2017, the terminology was changed from bariatric surgery to metabolic surgery. How such large changes could have occurred in the ADA guidelines? Because many patients have reached diabetes remission through metabolic surgery, and the long-term benefit and cost-effectiveness have been strongly proven by historical randomized controlled trials and high-quality studies. This review demonstrates how the recommendations for the treatment of obesity in patients with diabetes have changed in diabetes treatment guidelines and summarizes the evidence behind this change.

Influence of type 2 sodium-glucose co-transporter inhibitors (dapagliflozin) on the indicators of total mortality in patients with type 2 diabetes (CARDIA-MOS study, Moscow)

BACKGROUND: The widespread use in clinical practice of drugs with cardio- and nephroprotective properties, in particular, sodium-glucose cotransporter type 2 inhibitors (SGLT2i), is based on the results of large-scale international randomized trials. Meanwhile, there are no data demonstrating the possibility of the influence of these drugs on mortality rates in real clinical practice in Russian patients. To study this issue, a CARDIA-MOS study was conducted on a population of patients with type 2 diabetes (T2DM) in Moscow.

AIM: To study the effect of SGLT2i on the total mortality of patients with T2DM in Moscow.

MATERIALS AND METHODS: To assess the frequency of different outcomes, two samples of patients were formed according to predetermined criteria: 1) patients who started therapy with SGLT2i (dapagliflozin) in 2017; 2) a control group of patients corresponding to the main group in terms of key indicators: age, duration of T2DM, presence of cardiovascular diseases, use of insulin therapy, HbA1c level.

RESULTS: Firstly, an analysis of the data of 499 patients who started treatment with dapagliflozin in 2017, as well as 499 patients in the control group (n = 998) was made. The baseline characteristics of the patients were generally comparable. Pre-study SBP and HbA1c were worse in the dapagliflozin group. The use of dapagliflozin was associated with a 39% reduction in the relative risk of death from all causes (RR 0.614, 95% CI 0.417–0.903, p = 0.013), led to a decrease in HbA1c levels by 0.8% (from 8.5 to 7.7%, p<0.001) for 48 months. observations. The safety profile of dapagliflozin was comparable to that of the control group

CONCLUSION: The use of dapagliflozin in the treatment of patients with T2DM can reduce overall mortality and improve glycemic control.

Therapeutic Potential of miRNAs for Type 2 Diabetes Mellitus: An Overview

MicroRNA(miRNA)s have been identified as an emerging class for therapeutic interventions mainly due to their extracellularly stable presence in humans and animals and their potential for horizontal transmission and action. However, treating Type 2 diabetes mellitus using this technology has yet been in a nascent state. MiRNAs play a significant role in the pathogenesis of Type 2 diabetes mellitus establishing the potential for utilizing miRNA-based therapeutic interventions to treat the disease. Recently, the administration of miRNA mimics or antimiRs in-vivo has resulted in positive modulation of glucose and lipid metabolism. Further, several cell culture-based interventions have suggested beta cell regeneration potential in miRNAs. Nevertheless, few such miRNA-based therapeutic approaches have reached the clinical phase. Therefore, future research contributions would identify the possibility of miRNA therapeutics for tackling T2DM. This article briefly reported recent developments on miRNA-based therapeutics for treating Type 2 Diabetes mellitus, associated implications, gaps, and recommendations for future studies.

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

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

Fasting Substrate Concentrations Predict Cardiovascular Outcomes in the CANagliflozin cardioVascular Assessment Study (CANVAS)

OBJECTIVE

To examine whether the circulating substrate mix may be related to the incidence of heart failure (HF) and cardiovascular (CV) mortality and how it is altered by canagliflozin treatment.

RESEARCH DESIGN AND METHODS

We measured fasting glucose, free fatty acids (FFA), glycerol, β-hydroxybutyrate, acetoacetate, lactate, and pyruvate concentrations in 3,581 samples from the CANagliflozin cardioVascular Assessment Study (CANVAS) trial at baseline and at 1 and 2 years after randomization. Results were analyzed by univariate and multivariate Cox proportional hazards models.

RESULTS

Patients in the lowest baseline FFA tertile were more often men with a longer duration of type 2 diabetes (T2D), higher urinary albumin excretion, lower HDL-cholesterol levels, higher history of CV disease (CVD), and higher use of statins and insulin. When all seven metabolites were used as predictors, FFA were inversely associated with incident hospitalized HF (hazard ratio [HR] 0.33 [95% CI 0.21-0.55]), while glycerol was a positive predictor (2.21 [1.45-3.35]). In a model further adjusted for 16 potential confounders, including prior HF and CVD and pharmacologic therapies, FFA remained a significant negative predictor. FFA and glycerol also predicted CV mortality (HR 0.53 [95% CI 0.35-0.81] and 1.81 [1.26-2.58], respectively) and all-cause death (0.50 [0.36-0.70] and 1.64 [1.22-2.18]). When added to these models, background insulin therapy was an independent positive predictor of risk of death. Canagliflozin treatment significantly increased plasma FFA and β-hydroxybutyrate regardless of background antihyperglycemic therapy.

CONCLUSIONS

A constitutive metabolic setup consisting of higher lipolysis may be beneficial in delaying or preventing hospitalized HF; a further stimulation of lipolysis by canagliflozin may reinforce this influence.

Comparison of the effects of empagliflozin and glimepiride on endothelial function in patients with type 2 diabetes: A randomized controlled study

Patients with type 2 diabetes who have cardiovascular disease and are receiving empagliflozin have a lower rate of primary composite cardiovascular outcomes. In contrast, glimepiride increases cardiovascular hospitalization when combined with metformin. Here, we assessed the effects of empagliflozin and glimepiride on endothelial function using flow-mediated dilation (FMD). In this prospective, open-label, randomized, parallel-group study, 63 patients with type 2 diabetes received metformin and insulin glargine U100 for 12 weeks. This was followed by additional treatment with empagliflozin or glimepiride for 12 weeks. The primary outcome was the change in the FMD measurement (ΔFMDs) at 24 weeks of additional treatment. Secondary outcomes comprised changes in metabolic markers and body composition. The empagliflozin group (n = 33) and glimepiride group (n = 30) showed no significant differences in ΔFMDs (empagliflozin, −0.11 [95%CI: -1.02, 0.80]%; glimepiride, −0.34 [95%CI: -1.28, 0.60]%; P = 0.73). Additionally, changes in glycated hemoglobin were similar between the two groups. However, a significant difference in body weight change was observed (empagliflozin, −0.58 [95%CI: -1.60, 0.43] kg; glimepiride, 1.20 [95%CI: 0.15, 2.26] kg; P = 0.02). Moreover, a body composition analysis revealed that body fluid volume significantly decreased after empagliflozin treatment (baseline, 35.8 ± 6.8 L; after 12 weeks, −0.33 ± 0.72 L; P = 0.03). Hence, although empagliflozin did not improve endothelial function compared with glimepiride for patients with type 2 diabetes, it did decrease body fluid volumes. Thus, the coronary-protective effect of empagliflozin is not derived from endothelial function protection, but rather from heart failure risk reduction.

Trial registration: This trial was registered on September 13, 2016; UMIN000024001.

An integrative transcriptional logic model of hepatic insulin resistance

Abnormalities of lipid/lipoprotein and glucose metabolism are hallmarks of hepatic insulin resistance in type 2 diabetes. The former antedate the latter, but the latter become progressively refractory to treatment and contribute to therapeutic failures. It's unclear whether the two processes share a common pathogenesis and what underlies their progressive nature. In this study, we investigated the hypothesis that genes in the lipid/lipoprotein pathway and those in the glucose metabolic pathway are governed by different transcriptional regulatory logics that affect their response to physiologic (fasting/refeeding) as well as pathophysiologic cues (insulin resistance and hyperglycemia). To this end, we obtained genomic and transcriptomic maps of the key insulin-regulated transcription factor, FoxO1, and integrated them with those of CREB, PPAR-α, and glucocorticoid receptor. We found that glucose metabolic genes are primarily regulated by promoter and intergenic enhancers in a fasting-dependent manner, while lipid genes are regulated through fasting-dependent intron enhancers and fasting-independent enhancerless introns. Glucose genes also showed a remarkable transcriptional resiliency (i.e., the ability to compensate following constitutive FoxO1 ablation through an enrichment of active marks at shared PPAR-α/FoxO1 regulatory elements). Unexpectedly, insulin resistance and hyperglycemia were associated with a "spreading" of FoxO1 binding to enhancers and the emergence of unique target sites. We surmise that this unusual pattern correlates with the progressively intractable nature of hepatic insulin resistance. This transcriptional logic provides an integrated model to interpret the combined lipid and glucose abnormalities of type 2 diabetes.

Functionalized Gadofullerene Ameliorates Impaired Glycolipid Metabolism in Type 2 Diabetic Mice

The soaring global prevalence of diabetes makes it urgent to explore new drugs with high efficacy and safety. Nanomaterial-derived bioactive agents are emerging as one of the most promising candidates for biomedical application. In the present study, we investigated the anti-diabetic effects of a functionalized gadofullerene (GF) using obese db/db and non-obese MKR mouse T2DM models. In both mouse models, the diabetic phenotypes including hyperglycemia, impaired glucose tolerance and insulin sensitivity were ameliorated following 2 or 4 weeks of i.p. administration of GF. GF lowered blood glucose levels in a dose-dependent manner. Importantly, the restored blood glucose levels could persist 10 days after withdrawal of GF treatment. The hepatic AKT/GSK3β/FoxO1 pathway is shown to be the main target of GF for re-balancing gluconeogenesis and glycogen synthesis in vivo and in vitro. In addition, GF treatment significantly reduced weight gain of db/db mice with reduced hepatic fat storage by the inhibition of de novo lipogenesis through mTOR/S6K/SREBP1 pathway. Our data provide compelling evidence to support the promising application of GF for the treatment of T2DM.

Ultrasound-assisted enzymatic extraction of Corni Fructus alpha-glucosidase inhibitors improves insulin resistance in HepG2 cells

Corni Fructus (CF) is a traditional medicine and beneficial food with multifaceted protective effects against diabetes and its complications. Since alpha-glucosidase inhibitors (GIs) are promising first-choice oral antihyperglycemic drugs for diabetes, we examined whether GIs from CF (GICF) are useful for diabetes treatment. Therefore, GICF was extracted by ultrasound-assisted enzymatic extraction (UAEE) that is optimized by a three-level, four-factor Box-Behnken design and determined by ultra-performance liquid chromatography. Compared to 36.31 mg g^-1 without enzyme treatment, the GICF yield increased to 70.44 mg g^-1via UAEE under optimum conditions (0.5% compound enzyme extracted in 23 min at 46 °C and pH 4.8). The activity (91.99%) of GICF was as predicted (93.28%). When GICF was used in an insulin-resistant HepG2 cell model, it significantly ameliorated the glucose metabolism in a dose-dependent manner. Our findings indicate that UAEE may be an innovative method for functional food extraction and a potential strategy for high-quality food ingredient (such as GI) production with high efficiency and productivity.

Regulatory role and mechanism of m6A RNA modification in human metabolic diseases

Metabolic diseases caused by disorders in amino acids, glucose, lipid metabolism, and other metabolic risk factors show high incidences in young people, and current treatments are ineffective. N⁶-methyladenosine (m⁶A) RNA modification is a post-transcriptional regulation of gene expression with several effects on physiological processes and biological functions. Recent studies report that m⁶A RNA modification is involved in various metabolic pathways and development of common metabolic diseases, making it a potential disease-specific therapeutic target. This review explores components, mechanisms, and research methods of m⁶A RNA modification. In addition, we summarize the progress of research on m⁶A RNA modification in metabolism-related human diseases, including diabetes, obesity, non-alcoholic fatty liver disease, osteoporosis, and cancer. Furthermore, opportunities and the challenges facing basic research and clinical application of m⁶A RNA modification in metabolism-related human diseases are discussed. This review is meant to enhance our understanding of the molecular mechanisms, research methods, and clinical significance of m⁶A RNA modification in metabolism-related human diseases.

Personalized approach for type 2 diabetes pharmacotherapy: where are we and where do we need to be?

INTRODUCTION

Cluster analysis has identified distinct groups of type 2 diabetes (T2D) subjects with distinct metabolic characteristics. Thus, personalizing pharmacologic therapy to individual phenotypic and pathophysiologic characteristics has potential to improve metabolic control and reduce risk of microvascular and macrovascular complications.

AREAS COVERED

The authors review the classification of T2D, genetic markers, pathophysiology and natural history of T2D, the ABCDE approach to therapy, the ADA/EASD stepwise approach to therapy, available antidiabetic agents, and provide a more rational therapeutic approach based upon pathophysiology and cardiovascular and renal outcome trials.

EXPERT OPINION

Although insulin resistance is the earliest detectable abnormality, overt T2D does not occur in the absence of progressive beta cell failure. Because of the complex etiology of T2D (Ominous Octet), initiation of therapy with combined agents that (i) target both insulin resistance and beta cell dysfunction and (ii) prevent macrovascular, as well as microvascular, complications will be required. The ratio of C-peptide at 120 minutes (OGTT) to baseline C-peptide predicts with high sensitivity who will respond to metformin, the response to glucose-lowering agents and provides a useful tool to guide optimal glucose lowering therapy.

Similar cardiovascular outcomes in patients with diabetes and established or high risk for coronary vascular disease treated with dulaglutide with and without baseline metformin

OBJECTIVE

Recent European Guidelines for Diabetes, Prediabetes and Cardiovascular Diseases introduced a shift in managing patients with type 2 diabetes at high risk for or established cardiovascular (CV) disease by recommending GLP-1 receptor agonists and SGLT-2 inhibitors as initial glucose-lowering therapy. This is questioned since outcome trials of these drug classes had metformin as background therapy. In this post hoc analysis, the effect of dulaglutide on CV events was investigated according to the baseline metformin therapy by means of a subgroup analysis of the Researching Cardiovascular Events with a Weekly Incretin in Diabetes (REWIND) trial.

RESEARCH DESIGN AND METHODS

Patients in REWIND (n = 9901; women: 46.3%; mean age: 66.2 years) had type 2 diabetes and either a previous CV event (31%) or high CV risk (69%). They were randomized (1:1) to sc. dulaglutide (1.5 mg/weekly) or placebo in addition to standard of care. The primary outcome was the first of a composite of nonfatal myocardial infarction, nonfatal stroke, and death from cardiovascular or unknown causes. Key secondary outcomes included a microvascular composite endpoint, all-cause death, and heart failure. The effect of dulaglutide in patients with and without baseline metformin was evaluated by a Cox regression hazard model with baseline metformin, dulaglutide assignment, and their interaction as independent variables. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by a Cox regression model with adjustments for factors differing at baseline between people with vs. without metformin, identified using the backward selection.

RESULTS

Compared to patients with metformin at baseline (n = 8037; 81%), those without metformin (n = 1864; 19%) were older and slightly less obese and had higher proportions of women, prior CV events, heart failure, and renal disease. The primary outcome occurred in 976 (12%) participants with baseline metformin and in 281 (15%) without. There was no significant difference in the effect of dulaglutide on the primary outcome in patients with vs. without metformin at baseline [HR 0.92 (CI 0.81-1.05) vs. 0.78 (CI 0.61-0.99); interaction P = 0.18]. Findings for key secondary outcomes were similar in patients with and without baseline metformin.

CONCLUSION

This analysis suggests that the cardioprotective effect of dulaglutide is unaffected by the baseline use of metformin therapy.

Electrical Features of the Diabetic Myocardium. Arrhythmic and Cardiovascular Safety Considerations in Diabetes

Diabetes is a chronic metabolic disease characterized by hyperglycemia in the absence of treatment. Among the diabetes-associated complications, cardiovascular disease is the major cause of mortality and morbidity in diabetic patients. Diabetes causes a complex myocardial dysfunction, referred as diabetic cardiomyopathy, which even in the absence of other cardiac risk factors results in abnormal diastolic and systolic function. Besides mechanical abnormalities, altered electrical function is another major feature of the diabetic myocardium. Both type 1 and type 2 diabetic patients often show cardiac electrical remodeling, mainly a prolonged ventricular repolarization visible in the electrocardiogram as a lengthening of the QT interval duration. The underlying mechanisms at the cellular level involve alterations on the expression and activity of several cardiac ion channels and their associated regulatory proteins. Consequent changes in sodium, calcium and potassium currents collectively lead to a delay in repolarization that can increase the risk of developing life-threatening ventricular arrhythmias and sudden death. QT duration correlates strongly with the risk of developing torsade de pointes, a form of ventricular tachycardia that can degenerate into ventricular fibrillation. Therefore, QT prolongation is a qualitative marker of proarrhythmic risk, and analysis of ventricular repolarization is therefore required for the approval of new drugs. To that end, the Thorough QT/QTc analysis evaluates QT interval prolongation to assess potential proarrhythmic effects. In addition, since diabetic patients have a higher risk to die from cardiovascular causes than individuals without diabetes, cardiovascular safety of the new antidiabetic drugs must be carefully evaluated in type 2 diabetic patients. These cardiovascular outcome trials reveal that some glucose-lowering drugs actually reduce cardiovascular risk. The mechanism of cardioprotection might involve a reduction of the risk of developing arrhythmia.

Effect of Dapagliflozin on Myocardial Insulin Sensitivity and Perfusion: Rationale and Design of The DAPAHEART Trial

INTRODUCTION

Sodium-glucose co-transporter-2 (SGLT-2) inhibitors have been shown to have beneficial effects on various cardiovascular (CV) outcomes in patients with type 2 diabetes (T2D) in primary prevention and in those with a high CV risk profile. However, the mechanism(s) responsible for these CV benefits remain elusive and unexplained. The aim of the DAPAHEART study will be to demonstrate that treatment with SGLT-2 inhibitors is associated with greater myocardial insulin sensitivity in patients with T2D, and to determine whether this improvement can be attributed to a decrease in whole-body (and tissue-specific) insulin resistance and to increased myocardial perfusion and/or glucose uptake. We will also determine whether there is an appreciable degree of improvement in myocardial-wall conditions subtended by affected and non-affected coronary vessels, and if this relates to changes in left ventricular function.

METHODS

The DAPAHEART trial will be a phase III, single-center, randomized, two-arm, parallel-group, double-blind, placebo-controlled study. A cohort of 52 T2D patients with stable coronary artery disease (without any previous history of myocardial infarction, with or without previous percutaneous coronary intervention), with suboptimal glycemic control (glycated hemoglobin [HbA1c] 7-8.5%) on their current standard of care anti-hyperglycemic regimen, will be randomized in a 1:1 ratio to dapagliflozin or placebo. The primary outcome is to detect changes in myocardial glucose uptake from baseline to 4 weeks after treatment initiation. The main secondary outcome will be changes in myocardial blood flow, as measured by 13N-ammonia positron emission tomography/computed tomography (PET/CT). Other outcomes include cardiac function, glucose uptake in skeletal muscle, adipose tissue, liver, brain and kidney, as assessed by fluorodeoxyglucose (FDG) PET-CT imaging during hyperinsulinemic-euglycemic clamp; pericardial, subcutaneous and visceral fat, and browning as observed on CT images during FDG PET-CT studies; systemic insulin sensitivity, as assessed by hyperinsulinemic-euglycemic clamp, glycemic control, urinary glucose output; and microbiota modification.

DISCUSSION

SGLT-2 inhibitors, in addition to their insulin-independent plasma glucose-lowering effect, are able to directly (substrate availability, fuel utilization, insulin sensitivity) as well as indirectly (cardiac after-load reduction, decreased risk factors for heart failure) affect myocardial functions. Our study will provide novel insights into how these drugs exert CV protection in a diabetic population.

TRIAL REGISTRATION

EudraCT No. 2016-003614-27; ClinicalTrials.gov Identifier: NCT03313752.

Impact of high glucose levels and glucose lowering on risk of ischaemic stroke: a Mendelian randomisation study and meta-analysis

AIMS/HYPOTHESIS

It is unclear whether glucose per se has a causal impact on risk of stroke and whether glucose-lowering drugs reduce this risk. This is important for the choice of treatment for individuals at risk. We tested the hypotheses that high plasma glucose has a causal impact on increased risk of ischaemic stroke, and that glucose-lowering drugs reduce this risk.

METHODS

Using a Mendelian randomisation design, we examined 118,838 individuals from two Copenhagen cohorts, the Copenhagen General Population Study and the Copenhagen City Heart Study, and 440,328 individuals from the MEGASTROKE study. Effects of eight glucose-lowering drugs on risk of stroke were summarised by meta-analyses.

RESULTS

In genetic, causal analyses, a 1 mmol/l higher plasma glucose had a risk ratio of 1.48 (95% CI 1.04, 2.11) for ischaemic stroke in the Copenhagen studies. The corresponding risk ratio from the MEGASTROKE study combined with the Copenhagen studies was 1.74 (1.31, 2.18). In meta-analyses of glucose-lowering drugs, the risk ratio for stroke was 0.85 (0.77, 0.94) for glucagon-like peptide-1 receptor agonists and 0.82 (0.69, 0.98) for thiazolidinediones, while sulfonylureas, dipeptidyl peptidase-4 inhibitors, sodium-glucose cotransporter 2 inhibitors, α-glucosidase inhibitors, meglitinides and metformin individually lacked statistical evidence of an effect on stroke risk.

CONCLUSIONS/INTERPRETATION

Genetically high plasma glucose has a causal impact on increased risk of ischaemic stroke. Treatment with glucose-lowering glucagon-like peptide-1 receptor agonists and thiazolidinediones reduces this risk. These results may guide clinicians in the treatment of individuals at high risk of ischaemic stroke.

Role of Dipeptidyl Peptidase-4 in Atherosclerotic Cardiovascular Disease in Humans and Animals with Chronic Stress

Exposure to psychosocial stress is a risk factor for cardiovascular disease, including vascular atherosclerosis-based cardiovascular disease (ACVD). Dipeptidyl peptidase-4 (DPP-4) is a complex enzyme that acts as a membrane-anchored cell surface exopeptidase. DPP-4 is upregulated in metabolic and inflammatory cardiovascular disorders. DPP-4 exhibits many physiological and pharmacological functions by regulating its extremely abundant substrates, such as glucagon-like peptide-1 (GLP-1). Over the last 10 years, emerging data have demonstrated unexpected roles of DPP-4 in extracellular and intracellular signaling, immune activation, inflammation, oxidative stress production, cell apoptosis, insulin resistance, and lipid metabolism. This mini-review focuses on recent novel findings in this field, highlighting a DPP-4-mediated regulation of GLP-1-dependent and -independent signaling pathways as a potential therapeutic molecular target in treatments of chronic psychological stress-related ACVD in humans and animals.

Association of Metformin and Abdominal Aortic Aneurysm Repair Outcomes

BACKGROUND

Metformin is a commonly used drug in diabetes mellitus treatment. Recently it has been suggested that the use of metformin on diabetes mellitus patients may lower the prevalence and slow the progression of AAA (abdominal aortic aneurysm) as well as the risk of rupture related mortality. The aim of this studywas to investigate the impact of metformin treatment on the risk of AAA repair related mortality and surgical complications.

METHODS

In this retrospective study, the clinical data of 306 patients, including 77 patients with diabetes mellitus, who underwent abdominal aortic aneurysm repair has been analyzed. Treatment outcomes have been investigated. The diabetes and metformin prescription status has been obtained from the medical history. Patients were divided into three groups: diabetes-free individuals, diabetics treated with metformin and diabetics treated with other glucose lowering drugs. The association between metformin treatment and AAA diameter, surgical complications and mortality were assessed using chi-square independence test and odds ratio analysis. In order to assess which factors are influencing AAA repair related complications and mortality a multi-variables analysis has been performed.

RESULTS

A significant protective effect of metformin treatment towards AAA repair related mortality (P = 0.019) and complications (P = 0.032) among patients suffering from diabetes mellitus was revealed. These findings were statistically insignificant when considering all groups of patients (diabetes-free individuals, diabetics treated with metformin and diabetics treated with other glucose lowering drugs).

CONCLUSION

Metformin may lower the risk of AAA repair related mortality and surgical complications among patients with diabetes.

Isoliquiritigenin attenuates inflammation and modulates Nrf2/caspase-3 signalling in STZ-induced aortic injury

OBJECTIVES

The current study provides evidence on the ameliorative impact of Isoliquiritigenin (ISL), a natural bioflavonoid isolated from licorice roots against diabetes mellitus (DM)-induced aortic injury in rats.

METHODS

DM was induced in male Sprague-Dawley rats by single I.P. injection of STZ (50 mg/kg). ISL was administrated daily (20 mg/kg, orally) for 8 wks.

KEY FINDINGS

Diabetic group showed a significant aortic injury with evidence of atherosclerotic lesions development. Daily ISL (20 mg/kg, orally) administration for 8 wks significantly restored aortic oxidative/antioxidative stress homeostasis via modulating NrF-2/Keap-1/HO-1. Moreover, ISL treatment restored aortic levels of IL-10 and dampened aortic levels of IL-6 and TNF-α. Caspase-3 expression significantly declined as well. Further, ISL treatment successfully suppressed aortic endothelin-1 (ET-1) expression and restored NO contents, eNOS immunostaining paralleled with retraction in atherosclerotic lesions development, and lipid deposition with histopathological architectural preservation and restoration of almost normal aortic thickness.

CONCLUSION

ISL can be proposed to be an effective protective therapy to prevent progression of DM-induced vascular injury and to preserve aortic integrity.

Drug Discovery and Development of Novel Therapeutics for Inhibiting TMAO in Models of Atherosclerosis and Diabetes

Diabetes mellitus exists as a comorbidity with congestive heart failure (CHF). However, the exact molecular signaling mechanism linking CHF as the major form of mortality from diabetes remains unknown. Type 2 diabetic patients display abnormally high levels of metabolic products associated with gut dysbiosis. One such metabolite, trimethylamine N-oxide (TMAO), has been observed to be directly related with increased incidence of cardiovascular diseases (CVD) in human patients. TMAO a gut-liver metabolite, comes from the metabolic degenerative product trimethylamine (TMA) that is produced from gut microbial metabolism. Elevated levels of TMAO in diabetics and obese patients are observed to have a direct correlation with increased risk for major adverse cardiovascular events. The pro-atherogenic effect of TMAO is attributed to enhancing inflammatory pathways with cholesterol and bile acid dysregulation, promoting foam cell formation. Recent studies have revealed several potential therapeutic strategies for reducing TMAO levels and will be the central focus for the current review. However, few have focused on developing rational drug therapeutics and may be due to the gaps in knowledge for understanding the mechanism by which microbial TMA producing enzymes and hepatic flavin-containing monoxygenase (FMO) can work together in preventing elevation of TMAO levels. Therefore, it is critical to understand the advantages of developing a novel rational drug design strategy that manipulates FMO production of TMAO and TMA production by microbial enzymes. This review will focus on the inspection of FMO manipulation, as well as gut microbiota dysbiosis and its influence on metabolic disorders including cardiovascular disease and describe novel potential pharmacological therapeutic development.

Evaluating the impact of AMPK activation, a target of metformin, on risk of cardiovascular diseases and cancer in the UK Biobank: a Mendelian randomisation study

AIMS/HYPOTHESIS

Whether metformin reduces cardiovascular or cancer risk is unclear owing to concerns over immortal time bias and confounding in observational studies. This study evaluated the effect of AMP-activated protein kinase (AMPK), the target of metformin, on risk of cardiovascular disease and cancer.

METHODS

This is a Mendelian randomisation design, using AMPK, the pharmacological target of metformin, to infer the AMPK pathway-dependent effects of metformin on risk of cardiovascular disease and cancer in participants of white British ancestry in the UK Biobank.

RESULTS

A total of 391,199 participants were included (mean age 56.9 years; 54.1% women), including 26,690 cases of type 2 diabetes, 38,098 cases of coronary artery disease and 80,941 cases of overall cancer. Genetically predicted reduction in HbA_1c (%) instrumented by AMPK variants was associated with a 61% reduction in risk of type 2 diabetes (OR 0.39; 95% CI 0.20, 0.78; p = 7.69 × 10^-3), a 53% decrease in the risk of coronary artery disease (OR 0.47; 95% CI 0.26, 0.84; p = 0.01) and a 44% decrease in the risk of overall cancer (OR 0.56; 95% CI 0.36, 0.85; p = 7.23 × 10^-3). Results were similar using median or quartiles of AMPK score, with dose-response effects (p for trend = 4.18 × 10^-3 for type 2 diabetes, 4.37 × 10^-3 for coronary artery disease and 4.04 × 10^-3 for overall cancer).

CONCLUSIONS/INTERPRETATION

This study provides some genetic evidence that AMPK activation by metformin may protect against cardiovascular disease and cancer, which needs to be confirmed by randomised controlled trials.

A time to revisit the two oldest prandial anti-diabetes agents: acarbose and repaglinide

PURPOSE

Compared with newer prandial anti-diabetes agents, repaglinide and acarbose are unique in being globally available in generic versions, being oral, and being the cheapest of all. The aim of this study was to compare their efficacy when used alone or in combination.

METHODS

In a randomized, double-blind, prospective study, 358 recently diagnosed type 2 diabetes (T2D) patients, who on a combined therapy with metformin and insulin glargine had a fasting plasma glucose (FGP) of <7.2 mmol/L but a 2-h postprandial plasma glucose (2hPPG) >10 mmol/L, were assigned to three groups of additional treatment with either repaglinide, acarbose, or repaglinide-plus-acarbose for 4 months.

RESULTS

With intention-to-treat analysis, 63% of repaglinide group, 45.4 percent of acarbose group, and 75.7% of repaglinide-plus-acarbose group reached the primary endpoint of 2hPPG < 10 mmol/L while maintaining FPG < 7.2 mmol/L. Treatment adherence rate was 75.6% with repaglinide, 61.4% with acarbose, and 81.3% with repaglinide-plus-acarbose (p = 0.001). Among the groups, weight was significantly lower in acarbose group (p < 0.05). Twenty-one percent of repaglinide patients, 4.9% of acarbose subjects, and 10.3% of repaglinide-plus-acarbose cases reported at least one episode of hypoglycemia (p < 0.005). HbA1C and basal insulin requirement were significantly lower in repaglinide group (p = 0.004, p = 0.0002). Triglycerides were lowest in acarbose group (p = 0.005).

CONCLUSIONS

Both acarbose and repaglinide were vastly effective in lowering postprandial hyperglycemia of recently diagnosed T2D. When combined, they were even more efficacious and the disease had a better outcome. Compared with newer peers, these two are particularly useful where and when cost consideration in diabetes treatment is a prime concern.

A randomized controlled trial of metformin on left ventricular hypertrophy in patients with coronary artery disease without diabetes: the MET-REMODEL trial

Aim

We tested the hypothesis that metformin may regress left ventricular hypertrophy (LVH) in patients who have coronary artery disease (CAD), with insulin resistance (IR) and/or pre-diabetes.

Methods and results

We randomly assigned 68 patients (mean age 65 ± 8 years) without diabetes who have CAD with IR and/or pre-diabetes to receive either metformin XL (2000 mg daily dose) or placebo for 12 months. Primary endpoint was change in left ventricular mass indexed to height^1.7 (LVMI), assessed by magnetic resonance imaging. In the modified intention-to-treat analysis (n = 63), metformin treatment significantly reduced LVMI compared with placebo group (absolute mean difference −1.37 (95% confidence interval: −2.63 to −0.12, P = 0.033). Metformin also significantly reduced other secondary study endpoints such as: LVM (P = 0.032), body weight (P = 0.001), subcutaneous adipose tissue (P = 0.024), office systolic blood pressure (BP, P = 0.022) and concentration of thiobarbituric acid reactive substances, a biomarker for oxidative stress (P = 0.04). The glycated haemoglobin A1C concentration and fasting IR index did not differ between study groups at the end of the study.

Conclusion

Metformin treatment significantly reduced LVMI, LVM, office systolic BP, body weight, and oxidative stress. Although LVH is a good surrogate marker of cardiovascular (CV) outcome, conclusive evidence for the cardio-protective role of metformin is required from large CV outcomes trials.

The DPP-IV inhibitor saxagliptin promotes the migration and invasion of papillary thyroid carcinoma cells via the NRF2/HO1 pathway

Dipeptidyl peptidase-IV (DPP-IV) inhibitors are used to control blood glucose levels in patients with type 2 diabetes. However, the influence of DPP-IV inhibitors on malignant tumors remains unknown. The present study aimed to investigate the effect of the DPP-IV inhibitor saxagliptin on thyroid carcinoma cells. Transwell assays and a nude mouse lung metastasis model were used to evaluate the invasion and metastasis of thyroid carcinoma cells. Western blotting was used to determine the protein levels of migration and invasion-related molecules. We tested the expression and distribution of nuclear factor, erythroid 2 like 2 (NRF2) in thyroid carcinoma cells with and without saxagliptin. Furthermore, we silenced NRF2 and observed saxagliptin's effect on migration and invasion. Quantitative real-time reverse transcription PCR (qRT-PCR) and western blotting were then used to measure the expression of NFR2's downstream molecules (heme oxygenase 1 (HO1), matrix metalloproteinase 2 (MMP2), and vascular endothelial growth factor (VEGF)). A luciferase reporter assay was used to validate whether NRF2 could regulate the transcriptional activity of the HO1 promoter. Saxagliptin enhanced the migratory and invasive ability of thyroid carcinoma cells. MMP2 and VEGF levels were also elevated by saxagliptin treatment. We found that saxagliptin treatment increases the nuclear and cytoplasmic accumulation NRF2. Silencing NRF2 abolished the effect of saxagliptin on migration and invasion. Accordingly, NRF2 silencing downregulated HO1, MMP2, and VEGF levels. The luciferase assay showed that NRF2 activated transcription from the HO1 promoter. Saxagliptin could promote this transcriptional activity by upregulating NRF2. Saxagliptin enhanced the migratory and invasive ability of human thyroid carcinoma cells, as well as the expression of MMP2 and VEGF, by activating the NRF2/HO1 pathway.

Cardiovascular Risk and Statin Therapy Considerations in Women

Despite major progress in the prevention and treatment of cardiovascular diseases, women remain an underdiagnosed and insufficiently treated group, with higher hospitalization and death rates compared to men. Obesity, more frequently encountered in women, raises the risk of metabolic syndrome and cardiovascular diseases as women age. There are some differences based on sex regarding the screening, diagnosis, and treatment of dyslipidemia, as it has been observed that women are less frequently prescribed statins and, when they are, they receive lower doses, even after myocardial infarction or coronary revascularization. Real-life data show that, compared to men, women are at higher risk of non-adherence to statin treatment and are more predisposed to discontinue treatment because of side effects. Statin metabolism has some particularities in women, due to a lower glomerular filtration rate, higher body fat percentage, and overall faster statin metabolism. In women of fertile age, before initiating statin treatment, contraception methods should be discussed because statins may have teratogenic effects. Older women have a higher likelihood of polypharmacy, with greater potential for drug interactions when prescribing a statin.

Metformin Shortens Prolonged QT Interval in Diabetic Mice by Inhibiting L-Type Calcium Current: A Possible Therapeutic Approach

The incidence and mortality of cardiovascular disease in diabetic patients are 2-3 times higher than those in non-diabetic patients. Abnormal function of the L-type calcium channel in myocardial tissue might result in multiple cardiac disorders such as a prolonged QT interval. Therefore, QT prolongation is an independent risk factor of cardiovascular disease in patients with diabetes mellitus. Metformin, a hypoglycemic agent, is widely known to effectively reduce the occurrence of macrovascular diseases. The aim of the present study was to evaluate the effect of metformin on prolonged QT interval and to explore potential ionic mechanisms induced by diabetes. Diabetic mouse models were established with streptozotocin and an electrocardiogram was used to monitor the QT interval after 4 weeks of metformin treatment in each group. Action potential duration (APD) and L-type calcium current (I_Ca-L) were detected by patch-clamp in isolated mice ventricular cardiomyocytes and neonatal cardiomyocytes of mice. The expression levels of CACNA1C mRNA and Cav1.2 were measured by real-time PCR, western blot and immunofluorescence. A shortened QT interval was observed after 4 weeks of metformin treatment in diabetic mice. Patch-clamp results revealed that both APD and I_Ca-L were shortened in mouse cardiomyocytes. Furthermore, the expression levels of CACNA1C mRNA and Cav1.2 were decreased in the metformin group. The same results were also obtained in cultured neonatal mice cardiomyocytes. Overall, these results verify that metformin could shorten a prolonged QT interval by inhibiting the calcium current, suggesting that metformin may play a role in the electrophysiology underlying diabetic cardiopathy.

Impact of preexisting type 2 diabetes mellitus and antidiabetic drugs on all-cause and cause-specific mortality among Medicaid-insured women diagnosed with breast cancer

BACKGROUND

We investigated the influence preexisting type 2 diabetes mellitus (T2DM) and antidiabetic drugs have on all-cause and cause-specific mortality among Medicaid-insured women diagnosed with breast cancer.

METHODS

9221 women aged <64 years diagnosed with breast cancer and reported to the New York State (NYS) Cancer Registry from 2004 to 2016 were linked with Medicaid claims. Preexisting T2DM was determined by three diagnosis claims for T2DM with at least one claim prior to breast cancer diagnosis and a prescription claim for an antidiabetic drug within three months following breast cancer diagnosis. Estimated menopausal status was determined by age (premenopausal age <50; postmenopausal age ≥50). Hazard ratios (HR) and 95 % confidence intervals (95 %CI) were calculated with Cox proportional hazards regression, adjusting for confounders.

RESULTS

Women with preexisting T2DM had greater all-cause (HR = 1.40; 95 %CI 1.21, 1.63), cancer-specific (HR = 1.24; 95 %CI 1.04, 1.47), and cardiovascular-specific (HR = 2.46; 95 %CI 1.54, 3.90) mortality hazard compared to nondiabetic women. In subgroup analyses, the association between T2DM and all-cause mortality was found among non-Hispanic White (HR 1.78 95 %CI 1.38, 2.30) and postmenopausal (HR = 1.47; 95 %CI 1.23, 1.77) women, but not among other race/ethnicity groups or premenopausal women. Additionally, compared to women prescribed metformin, all-cause mortality hazard was elevated among women prescribed sulfonylurea (HR = 1.44; 95 %CI 1.06, 1.94) or insulin (HR = 1.54; 95 %CI 1.12, 2.11).

CONCLUSION

Among Medicaid-insured women with breast cancer, those with preexisting T2DM have an increased mortality hazard, especially when prescribed sulfonylurea or insulin. Further research is warranted to determine the role antidiabetic drugs have on survival among women with breast cancer.

A PKB-SPEG signaling nexus links insulin resistance with diabetic cardiomyopathy by regulating calcium homeostasis

Diabetic cardiomyopathy is a progressive disease in diabetic patients, and myocardial insulin resistance contributes to its pathogenesis through incompletely-defined mechanisms. Striated muscle preferentially expressed protein kinase (SPEG) has two kinase-domains and is a critical cardiac regulator. Here we show that SPEG is phosphorylated on Ser²⁴⁶¹/Ser²⁴⁶²/Thr²⁴⁶³ by protein kinase B (PKB) in response to insulin. PKB-mediated phosphorylation of SPEG activates its second kinase-domain, which in turn phosphorylates sarcoplasmic/endoplasmic reticulum calcium-ATPase 2a (SERCA2a) and accelerates calcium re-uptake into the SR. Cardiac-specific deletion of PKBα/β or a high fat diet inhibits insulin-induced phosphorylation of SPEG and SERCA2a, prolongs SR re-uptake of calcium, and impairs cardiac function. Mice bearing a Speg^3A mutation to prevent its phosphorylation by PKB display cardiac dysfunction. Importantly, the Speg^3A mutation impairs SERCA2a phosphorylation and calcium re-uptake into the SR. Collectively, these data demonstrate that insulin resistance impairs this PKB-SPEG-SERCA2a signal axis, which contributes to the development of diabetic cardiomyopathy.

Molecular mechanisms linking myocardial insulin resistance to diabetic cardiomyopathy are incompletely understood. Here the authors show that myocardial insulin resistance impairs a PKB-SPEG-SERCA2a signaling axis, which contributes to the development of diabetic cardiomyopathy.

Are the cardiovascular and kidney benefits of empagliflozin influenced by baseline glucose-lowering therapy?

AIMS

In the EMPA-REG OUTCOME® trial, the sodium-glucose cotransporter 2 inhibitor empagliflozin when given in addition to standard care improved cardiovascular (CV) and renal outcomes, and reduced mortality. Trial participants were on a variety of glucose-lowering therapies at baseline, some of which could potentially affect CV risk. This analysis investigated whether the use of background diabetes therapy affected the risk of CV death, hospitalizations for heart failure, and progression of chronic kidney disease, among patients treated with empagliflozin.

MATERIALS AND METHODS

Patients meeting inclusion and exclusion criteria were randomized to placebo, empagliflozin 10 mg or empagliflozin 25 mg; glucose-lowering therapy was to remain unchanged for 12 weeks and then adjusted to achieve glycaemic control according to local guidelines. Differences in risk of cardio-renal outcomes between empagliflozin and placebo by baseline use of metformin, sulphonylurea (SU) and insulin were assessed using a Cox proportional hazards model.

RESULTS

Of 7020 eligible patients, 74% were receiving metformin, 43% SU and 48% insulin at baseline (each alone or in combination); the most common regimens were metformin plus SU (20%) and metformin plus insulin (20%). Empagliflozin reduced the risk of CV death irrespective of the use of: metformin [with: hazard ratio (HR) 0.71 (95% confidence interval, CI, 0.54-0.94); without: 0.46 (0.32-0.68); P_interaction = 0.07]; SU [with: HR 0.64 (0.44-0.92); without: 0.61 (0.46-0.81); P_interaction = 0.85]; or insulin [with: HR 0.63 (0.46-0.85); without: 0.61 (0.44-0.85); P_interaction = 0.92]. Reductions in three-point major adverse CV events, hospitalizations for heart failure, and all-cause mortality were consistent across subgroups of baseline therapies. Empagliflozin reduced the risks of incident or worsening nephropathy versus placebo irrespective of the use of SU or insulin at baseline (P_interaction > 0.05), but there was a greater reduction in this risk for patients not using metformin [HR 0.47 (95% CI 0.37-0.59)] versus those using metformin [HR 0.68 (95% CI 0.58-0.79)] at baseline (P_interaction = 0.01).

CONCLUSIONS

The addition of empagliflozin to antihyperglycaemic regimens of patients with type 2 diabetes and CV disease consistently reduced their risks of adverse CV outcomes and mortality irrespective of baseline use of metformin, SU or insulin. For chronic kidney disease progression, there may be a larger benefit from empagliflozin in those patients who are not using metformin.