Metformin-inclusive therapy reduces the risk of stroke in patients with diabetes: a 4-year follow-up study

Clinical efficacy and cost-effectiveness of metformin in different patient populations: A narrative review of real-world evidence

Over the past two decades, diabetes pharmacopoeia has flourished, with new drugs that, on top of their glucose-lowering efficacy, have been shown to protect the heart and the kidney. Despite these new opportunities, metformin retains a pivotal role among glucose-lowering agents. As one of the few available insulin sensitizers, metformin is an effective, safe, and overall well-tolerated drug backed by over 60 years of clinical experience, including evidence for potential benefits beyond glucose reduction across different ages, sexes, genetic backgrounds, geographical areas, and stages of disease. Although there is some discussion of whether metformin offers the most effective front-line option in newly diagnosed type 2 diabetes (T2D), it remains a natural companion to all other glucose-lowering agents. Furthermore, metformin comes at a very low cost and, as such, it has extremely high cost-effectiveness, particularly given the serious economic burden associated with diabetes complications. This financial advantage is particularly relevant in resource-constrained healthcare systems, where the affordability of metformin may be instrumental in implementing an effective treatment in an evergrowing number of individuals. We present here compelling real-world evidence in support of the clinical efficacy and cost-effectiveness of metformin across different patient populations, highlighting areas where more population-based studies are needed to further incorporate and consolidate its use in the pharmacological management of T2D.

Influencing factors of stroke in patients with type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Stroke stands as a significant macrovascular complication among individuals with Type 2 diabetes mellitus (T2DM), often resulting in the primary cause of mortality and disability within this patient demographic. Presently, numerous studies have been conducted to investigate the underlying causes of stroke in individuals with T2DM, yet the findings exhibit inconsistencies.

OBJECTIVE

This paper aims to consolidate and summarize the available evidence concerning the influential factors contributing to stroke among patients diagnosed with T2DM.

METHODS

We conducted a comprehensive search across multiple databases, including Cochrane Library, PubMed, Web Of Science, Embase, China Biology Medicine (CBM), China National Knowledge Infrastructure (CNKI), Wanfang and Weipu up to August 2023. Google Scholar was also searched to retrieve gray literature. We calculated odds ratios (OR) and 95% confidence intervals (CI) using Stata software.

RESULTS

Our analysis encompassed 43 observational studies, exploring factors across sociodemographic, biochemical, complications, and hypoglycemic agent categories. The findings identified several risk factors for stroke in patients with T2DM: age, gender, T2DM duration, hypertension, body-mass index (BMI), smoking, Glycated hemoglobin (HbA1c), estimated Glomerular Filtration Rate (eGFR), albuminuria, Triglycerides (TG), Low density lipoprotein cholesterol (LDL-C), Coronary heart disease (CHD), Atrial fibrillation (AF), diabetic retinopathy (DR), Peripheral vascular disease (PVD), and carotid plaque. Conversely, exercise, High density lipoprotein cholesterol (HDL-C), metformin (MET), pioglitazone, and metformin combination therapy emerged as protective factors.

CONCLUSION

This study underscores the multitude of influencing factors contributing to stroke in people with T2DM patients, among which the microvascular complications of T2DM play an most important role. Therefore, we emphasize the importance of screening for microvascular complications in patients with T2DM. However, due to limitations arising from the number of articles reviewed, there remain areas where clarity is lacking. Further research efforts are warranted to expand upon and reinforce our current findings.

Neuroprotective effects of oral metformin before stroke on cerebral small-vessel disease

BACKGROUND

Metformin (MET) treatment prior to stroke might have neuroprotective effects other than hypoglycemic effects. This study evaluated whether MET treatment prior to stroke is associated with neurological severity and functional outcome in patients with stroke who were not indicated for endovascular treatment and whether the effects of MET differ for each ischemic stroke subtype.

METHODS

We investigated 160 type 2 diabetes mellitus patients with ischemic stroke without endovascular treatment who were taking some oral antidiabetic agents prior to stroke in two tertiary hospitals. Lower neurological severity was defined as a National Institutes of Health Stroke Scale score of 3 or lower on admission, and favorable functional outcome was defined as a modified Rankin Scale score = 0-2 at discharge. We analyzed the effects of MET on the neurological severity and functional outcome in each ischemic stroke subtype on logistic regression analysis with adjustments for multiple confounding factors.

RESULTS

MET treatment prior to stroke was associated with lower stroke severity and favorable functional outcome. In the stroke subtypes, MET use affected both neurological severity (P = 0.037) and functional outcome (P = 0.041) in only patients with small-vessel disease (SVD).

CONCLUSIONS

MET may be useful to improve the outcome of patients with SVD.

Effects of Metformin on Ischemia/Reperfusion Injury: New Evidence and Mechanisms

The search for new drugs with the potential to ensure therapeutic success in the treatment of cardiovascular diseases has become an essential pathway to follow for health organizations and committees around the world. In June 2021, the World Health Organization listed cardiovascular diseases as one of the main causes of death worldwide, representing 32% of them. The most common is coronary artery disease, which causes the death of cardiomyocytes, the cells responsible for cardiac contractility, through ischemia and subsequent reperfusion, which leads to heart failure in the medium and short term. Metformin is one of the most-used drugs for the control of diabetes, which has shown effects beyond the control of hyperglycemia. Some of these effects are mediated by the regulation of cellular energy metabolism, inhibiting apoptosis, reduction of cell death through regulation of autophagy and reduction of mitochondrial dysfunction with further reduction of oxidative stress. This suggests that metformin may attenuate left ventricular dysfunction induced by myocardial ischemia; preclinical and clinical trials have shown promising results, particularly in the setting of acute myocardial infarction. This is a review of the molecular and pharmacological mechanisms of the cardioprotective effects of metformin during myocardial ischemia-reperfusion injury.

The development and benefits of metformin in various diseases

Metformin has been used for the treatment of type II diabetes mellitus for decades due to its safety, low cost, and outstanding hypoglycemic effect clinically. The mechanisms underlying these benefits are complex and still not fully understood. Inhibition of mitochondrial respiratory-chain complex I is the most described downstream mechanism of metformin, leading to reduced ATP production and activation of AMP-activated protein kinase (AMPK). Meanwhile, many novel targets of metformin have been gradually discovered. In recent years, multiple pre-clinical and clinical studies are committed to extend the indications of metformin in addition to diabetes. Herein, we summarized the benefits of metformin in four types of diseases, including metabolic associated diseases, cancer, aging and age-related diseases, neurological disorders. We comprehensively discussed the pharmacokinetic properties and the mechanisms of action, treatment strategies, the clinical application, the potential risk of metformin in various diseases. This review provides a brief summary of the benefits and concerns of metformin, aiming to interest scientists to consider and explore the common and specific mechanisms and guiding for the further research. Although there have been countless studies of metformin, longitudinal research in each field is still much warranted.

Sodium-Glucose Co-transporter 2 Inhibitors Versus Metformin as the First-Line Treatment for Type 2 Diabetes: Is It Time for a Revolution?

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) have emerged as a promising therapeutic option for hyperglycemia and its complications. However, metformin remains the first-line pharmacological treatment in most algorithms for type 2 diabetes (T2D). Although metformin is generally believed to exert positive effects on cardiovascular (CV) outcomes, relevant data are mainly observational and potentially overinterpreted. Yet, it exerts numerous pleiotropic actions that favorably affect metabolism and diabetes comorbidities. CV outcome trials have demonstrated cardiorenal protection with SGLT2i among people at high CV risk and mostly on concomitant metformin therapy. However, post hoc analyses of these trials suggest that the cardiorenal effects of gliflozins are independent of background treatment and consistent across the full spectrum of CV risk. Considering the importance of addressing hyperglycemia as a means of preventing diabetic complications and significant knowledge gaps, particularly regarding the cost-effectiveness of SGLT2i in drug-naïve populations with T2D, the position of metformin in the management of people with diabetes at low CV risk remains solid for the moment. On the other hand, available evidence-despite its limitations-suggests that specific groups of people with T2D, particularly those with heart failure and kidney disease, could probably benefit more from treatment with SGLT2i. This narrative mini-review aims to discuss whether current evidence justifies the use of SGLT2i as the first-line treatment for T2D.

Metformin: evidence from preclinical and clinical studies for potential novel applications in cardiovascular disease

INTRODUCTION

For a long time, metformin has been the first-line treatment for glycaemic control in type 2 diabetes, however, the results of recent cardiovascular outcome trials of sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide 1 receptor agonists have caused many to question metformin's position in the guidelines. Although there are several plausible mechanisms by which metformin might have beneficial cardiovascular effects, for example its anti-inflammatory effects and metabolic properties, and numerous observational data suggesting improved cardiovascular outcomes with metformin use, the main randomised clinical trial data for metformin was published over 20 years ago. Nevertheless, the overwhelming majority of participants in contemporary type 2 diabetes trials were prescribed metformin.

AREAS COVERED

In this review we will summarise the potential mechanisms of cardiovascular benefit with metformin, before discussing clinical data in individuals with or without diabetes.

EXPERT OPINION

Metformin may have some cardiovascular benefit in patients with and without diabetes, however the majority of clinical trials were small and are before the use SGLT2 inhibitors and GLP1-RAs. Larger contemporary randomised trials with metformin evaluating its cardiovascular benefit are warranted.

Metformin mitigates amyloid β1-40-induced cognitive decline via attenuation of oxidative/nitrosative stress and neuroinflammation

Metformin is an antidiabetic medicine widely used for management of type 2 diabetes with neuroprotective effects and promising potential to attenuate cognitive impairment. The efficacy of metformin in attenuation of Alzheimer's disease (AD) pathology has not been well-documented. Thus, this study was designed to assess protective effect of metformin against Aβ_1-40-instigared cognitive impairment. After intra-CA1 microinjection of aggregated Aβ_1-40, rats received oral metformin (50 and/or 200 mg/kg/day) for two weeks. Cognition function was analyzed in various behavioral tasks besides measurement of hippocampal oxidative stress, apoptosis, and inflammation along with H&E staining and 3-nitrotyrosine (3-NT) immunohistochemistry. Obtained data showed significant improvement of discrimination score in novel object recognition test, higher alternation score in Y maze, greater latency in passive avoidance task, and lower working and reference memory errors in radial arm maze in metformin-treated Aβ-injured group. Moreover, metformin treatment attenuated hippocampal levels of nitrite, MDA, protein carbonyl, ROS, TNFα, GFAP, DNA fragmentation intensity, caspase 3 activity, AChE activity, and increased SOD activity and level of IL-10 as an anti-inflammatory factor. In addition, metformin treatment was associated with lower CA1 neuronal loss and it also decreased intensity of 3-NT immunoreactivity as an indicator of nitrosative stress. Taken together, obtained findings showed neuroprotective and anti-dementia property of metformin in male rats and this may have potential benefit in attenuation of cognitive decline and related complications in patients with neurodegenerative disorders such as AD besides diabetes mellitus.

Can metformin use reduce the risk of stroke in diabetic patients? A systematic review and meta-analysis

BACKGROUND AND AIM

Stroke and cardiovascular diseases are major causes of death and disability, especially among diabetic patients. Some studies have shown that metformin has been effective in preventing cardiovascular diseases. In this study, we aim to evaluate the effect of metformin on stroke in type 2 diabetic patients.

METHODS

A comprehensive search was conducted in Medline, Embase, Scopus, and Web of Science databases from their inception till 1st July 2022. Randomized clinical trials (RCT) and cohort studies were included. Two independent researchers screened the records, extracted the data, and assessed the risk of bias and certainty of evidence. Findings were reported as risk ratio (RR) and 95% confidence interval (CI). All statistical analyses were performed using the STATA 17.0 software package.

RESULTS

Analysis of 21 included studies with 1,392,809 patients demonstrated that metformin monotherapy was effective in reducing stroke risk in both RCTs (RR = 0.66, 95% CI: 0.50, 0.87 p = 0.004) and cohort studies (RR = 0.67, 95% CI: 0.55, 0.81, p < 0.0001). However, combined administration of metformin with other antihyperglycemic agents had no significant effect on stroke risk reduction in either the RCTs (RR = 0.92, 95% CI: 0.69, 1.22 p = 0.558) or the cohort studies (RR = 0.79, 95% CI: 0.59, 1.06, p = 0.122).

CONCLUSION

Low to moderate level of evidence in RCTs showed that metformin monotherapy could reduce stroke risk in type 2 diabetic patients. However, the preventive effect of metformin in stroke was not observed in patients who received a combination of metformin plus other hypoglycemic agents.

Metformin adherence and the risk of cardiovascular disease: a population-based cohort study

Background

Metformin is a potent antiglycemic agent, but its importance has receded owing to the launch of novel antidiabetic medications. The benefit of metformin includes not only blood sugar control but also anti-inflammation, autophagy activation, and neuroprotection. This study investigated the risk of cardiovascular disease (CVD) in people with type II diabetes mellitus (T2DM) who adhered to metformin after adding on a second-line antiglycemic agent.

Objectives

The purpose of this study was to investigate the benefits of metformin in CVD prevention in patients with T2DM.

Design

We designed the study by comparing the incident rate of CVD events in patients with T2DM who received metformin continually and who ceased metformin during 2002-2014.

Methods

Medical information was obtained from the National Health Insurance Research Database, and patients with T2DM receiving second-line antiglycemic agents were categorized into metformin-adherent and nonadherent groups according to prescription claims. The study outcomes were the incidence of CVD hospitalization, including stroke (ischemic and hemorrhagic) and myocardial infarction (MI).

Results

A total of 31,384 patients with T2DM constituted the metformin-adherent group and were 1:1 matched to nonadherent patients. Metformin adherence was associated with a lower risk of hospitalization due to stroke [adjusted hazard ratio (aHR) = 0.51, 95% confidence interval (CI): 0.43-0.59, p < 0.001] and MI (aHR = 0.47, 95% CI: 0.43-0.53, p < 0.001). The risk reduction persisted in both ischemic and hemorrhagic strokes. Our subgroup analysis revealed that the protective effect on stroke and MI hospitalization persisted in metformin-adherent patients, both sexes, patients aged ⩽65 or >65 years, and patients with or without concurrent insulin treatment.

Conclusions

This study revealed that metformin adherence in patients with T2DM who required a first-line treatment may reduce the risk of subsequent CVD. Despite the availability of numerous novel antiglycemic agents, metformin adherence by patients who require a combination of antiglycemic agents provides an additional benefit of CVD protection.

A review of stress-induced hyperglycaemia in the context of acute ischaemic stroke: Definition, underlying mechanisms, and the status of insulin therapy

The transient elevation of blood glucose produced following acute ischaemic stroke (AIS) has been described as stress-induced hyperglycaemia (SIH). SIH is common even in patients with AIS who have no previous diagnosis of diabetes mellitus. Elevated blood glucose levels during admission and hospitalization are strongly associated with enlarged infarct size and adverse prognosis in AIS patients. However, insulin-intensive glucose control therapy defined by admission blood glucose for SIH has not achieved the desired results, and new treatment ideas are urgently required. First, we explore the various definitions of SIH in the context of AIS and their predictive value in adverse outcomes. Then, we briefly discuss the mechanisms by which SIH arises, describing the dual effects of elevated glucose levels on the central nervous system. Finally, although preclinical studies support lowering blood glucose levels using insulin, the clinical outcomes of intensive glucose control are not promising. We discuss the reasons for this phenomenon.

The Effectiveness and Safety of Metformin Compared to Sulfonylureas in Diabetic Nephropathy: A Systematic Review

Metformin and sulphonylureas are the most commonly used first-line anti-diabetic agents. However, medical practice guidelines and clinical experience caution against using these drugs in severe diabetic kidney disease. Consequently, the choice of anti-diabetic medicine in various stages of diabetic nephropathy should balance the benefits and risks to the patient. We aim to synthesize available evidence on the effectiveness and safety of metformin concerning sulfonylureas in patients with diabetic renal disease. The COSMOS-E (Guidance on conducting systematic reviews and meta-analyses of observational studies of etiology) and MOOSE (Meta-Analyses and Systematic Reviews of Observational Studies in Epidemiology) guidelines were followed when designing the systematic review. The present study assessed the effectiveness of metformin and sulphonylurea monotherapy regarding renal function. Studies published from 2001 to 2022 were included. We have identified 570 records from PubMed, BioMed Central, LILACS (Literatura Latino-Americana e do Caribe em Ciências da Saúde), ScienceDirect, and PLoS (The Public Library of Science) Medicine databases. Eight cohort studies met the inclusion criteria. All studies reported adjusted hazard ratios with confidence limits. Metformin was found to be more effective in the following events: all-cause mortality, GFR (glomerular filtration rate), ESRD (end-stage renal disease) or death events, one-year risk of death or end-stage renal disease, cardiovascular events, heart failure hospitalization, and hypoglycemic episodes. However, metformin was less effective in acute renal replacement therapy, end-stage renal disease, and/or death, with a one-year risk of acute dialysis. Lactic acidosis was not significant with metformin. The present study recommends that metformin therapy is safe compared to sulfonylurea therapy in diabetic nephropathy patients, provided that the contraindications given in the guidelines are strictly adhered to.

Neuropharmacological efficacy of metformin for stroke in rodents: A meta-analysis of preclinical trials

Background: Stroke, including ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage (SAH), remains a leading cause of mortality globally. Different stroke subtypes have similar detrimental effects in multiple fields of health. Previous research has shown that metformin plays a neuroprotective role in experimental animal models of stroke; however, a preclinical quantitative analysis on the ability of metformin to treat stroke is still lacking. This meta-analysis evaluates the efficacy of metformin in improving stroke prognosis in rodent models of stroke. Methods: Relevant preclinical trials were retrieved from PubMed, EMBASE, and the Web of Science. The neurological score (NS), brain water content (BWC), infarct size, rotarod test, TUNEL, neuron quantity, microglia quantity, and p-AMPK levels were compared between a control group and a metformin group using the standardized mean difference (SMD) and corresponding confidence interval (CI). Quality was assessed with SYRCLE's risk of bias tool. Results: Fifteen articles published from 2010 to 2022 were included in the meta-analysis. The metformin group had statistically significant differences compared to the control group in the following aspects: NS (SMD -1.45; 95% CI -2.32, -0.58; p = 0.001), BWC (SMD -3.22; 95% CI -4.69, -1.76; p < 0.0001), infarct size (SMD -2.90; 95% CI -3.95, -1.85; p < 0.00001), rotarod test (SMD 2.55; 95% CI 1.87, 3.23; p < 0.00001), TUNEL (SMD -3.63; 95% CI -5.77, -1.48; p = 0.0009), neuron quantity (SMD 3.42; 95% CI 2.51, 4.34; p < 0.00001), microglia quantity (SMD -3.06; 95% CI -4.69, -1.44; p = 0.0002), and p-AMPK levels (SMD 2.92; 95% CI 2.02, 3.82; p < 0.00001). Furthermore, sensitivity analysis and stratified analysis were conducted for heterogeneous outcome indicators. Conclusion: Overall, metformin treatment improves severe outcomes triggered by stroke. Despite the limitations intrinsic to animal studies, this systematic review may provide a vital reference for future high-quality preclinical trials and clinical use.

Epicardial fat and atrial fibrillation: the perils of atrial failure

Obesity is a heterogeneous condition, characterized by different phenotypes and for which the classical assessment with body mass index may underestimate the real impact on cardiovascular (CV) disease burden. An epidemiological link between obesity and atrial fibrillation (AF) has been clearly demonstrated and becomes even more tight when ectopic (i.e. epicardial) fat deposition is considered. Due to anatomical and functional features, a tight paracrine cross-talk exists between epicardial adipose tissue (EAT) and myocardium, including the left atrium (LA). Alongside-and even without-mechanical atrial stretch, the dysfunctional EAT may determine a pro-inflammatory environment in the surrounding myocardial tissue. This evidence has provided a new intriguing pathophysiological link with AF, which in turn is no longer considered a single entity but rather the final stage of atrial remodelling. This maladaptive process would indeed include structural, electric, and autonomic derangement that ultimately leads to overt disease. Here, we update how dysfunctional EAT would orchestrate LA remodelling. Maladaptive changes sustained by dysfunctional EAT are driven by a pro-inflammatory and pro-fibrotic secretome that alters the sinoatrial microenvironment. Structural (e.g. fibro-fatty infiltration) and cellular (e.g. mitochondrial uncoupling, sarcoplasmic reticulum fragmentation, and cellular protein quantity/localization) changes then determine an electrophysiological remodelling that also involves the autonomic nervous system. Finally, we summarize how EAT dysfunction may fit with the standard guidelines for AF. Lastly, we focus on the potential benefit of weight loss and different classes of CV drugs on EAT dysfunction, LA remodelling, and ultimately AF onset and recurrence.

Effect of Dipeptidyl Peptidase-4 Inhibitors vs. Metformin on Major Cardiovascular Events Using Spontaneous Reporting System and Real-World Database Study

Background: Metformin had been recommended as the first-line treatment for type 2 diabetes since 2006 because of its low cost, high efficacy, and potential to reduce cardiovascular events, and thus death. However, dipeptidyl peptidase-4 (DPP-4) inhibitors are the most commonly prescribed first-line agents for patients with type 2 diabetes in Japan. Therefore, it is necessary to clarify the effect of DPP-4 inhibitors on preventing cardiovascular events, taking into consideration the actual prescription of antidiabetic drugs in Japan. Methods: This study examined the effect of DPP-4 inhibitors on preventing cardiovascular events. The Japanese Adverse Drug Event Report (JADER) database, a spontaneous reporting system in Japan, and the Japanese Medical Data Center (JMDC) Claims Database, a Japanese health insurance claims and medical checkup database, were used for the analysis. Metformin was used as the DPP-4 inhibitor comparator. Major cardiovascular events were set as the primary endpoint. Results: In the analysis using the JADER database, a signal of major cardiovascular events was detected with DPP-4 inhibitors (IC: 0.22, 95% confidence interval: 0.03–0.40) but not with metformin. In the analysis using the JMDC Claims Database, the hazard ratio of major cardiovascular events for DPP-4 inhibitors versus metformin was 1.01 (95% CI: 0.84–1.20). Conclusions: A comprehensive analysis using two different databases in Japan, the JADER and the JMDC Claims Database, showed that DPP-4 inhibitors, which are widely used in Japan, have a non-inferior risk of cardiovascular events compared to metformin, which is used as the first-line drug in the United States and Europe.

Effects of Long-term Metformin and Lifestyle Interventions on Cardiovascular Events in the Diabetes Prevention Program and Its Outcome Study

BACKGROUND

Lifestyle intervention and metformin have been shown to prevent diabetes; however, their efficacy in preventing cardiovascular disease associated with the development of diabetes is unclear. We examined whether these interventions reduced the incidence of major cardiovascular events over a 21-year median follow-up of participants in the DPP trial (Diabetes Prevention Program) and DPPOS (Diabetes Prevention Program Outcomes Study).

METHODS

During DPP, 3234 participants with impaired glucose tolerance were randomly assigned to metformin 850 mg twice daily, intensive lifestyle or placebo, and followed for 3 years. During the next 18-year average follow-up in DPPOS, all participants were offered a less intensive group lifestyle intervention, and unmasked metformin was continued in the metformin group. The primary outcome was the first occurrence of nonfatal myocardial infarction, stroke, or cardiovascular death adjudicated by standard criteria. An extended cardiovascular outcome included the primary outcome or hospitalization for heart failure or unstable angina, coronary or peripheral revascularization, coronary heart disease diagnosed by angiography, or silent myocardial infarction by ECG. ECGs and cardiovascular risk factors were measured annually.

RESULTS

Neither metformin nor lifestyle intervention reduced the primary outcome: metformin versus placebo hazard ratio 1.03 (95% CI, 0.78-1.37; P = 0.81) and lifestyle versus placebo hazard ratio 1.14 (95% CI, 0.87-1.50; P = 0.34). Risk factor adjustment did not change these results. No effect of either intervention was seen on the extended cardiovascular outcome.

CONCLUSIONS

Neither metformin nor lifestyle reduced major cardiovascular events in DPPOS over 21 years despite long-term prevention of diabetes. Provision of group lifestyle intervention to all, extensive out-of-study use of statin and antihypertensive agents, and reduction in the use of study metformin together with out-of-study metformin use over time may have diluted the effects of the interventions.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifiers: DPP (NCT00004992) and DPPOS (NCT00038727).

Metformin use is associated with low risk of case fatality and disability rates in first-ever stroke patients with type 2 diabetes

Background:

To assess the effectiveness of metformin treatment on long-term outcomes in first-ever stroke patients with type 2 diabetes mellitus (T2DM) in China.

Methods:

From August to September 2019, all patients with first-ever stroke and T2DM from 232 hospitals in China Mainland were included. The enrolled patients were divided into two groups: the metformin treatment (MT) and the no-metformin treatment (No-MT) groups. All discharged patients would receive a telephone follow-up at 12-month after admission.

Results:

In total, 7587 first-ever stroke patients with T2DM [age: median (IQR) = 66 (57–73) years; 57.35% male] were recruited. Out of those 7587 included patients, 3593 (47.36%) received MT. The in-hospital case fatality rate was lower in the MT group than the No-MT group [MT group versus No-MT group: 1.09% versus 2.30%; absolute difference = −1.75% (95% CI = −2.15 to −1.17%); OR = 0.63 (95% CI = 0.47 to 0.84)]. The 12-month case fatality rate was lower in the MT group than the No-MT group [4.72% versus 8.05%; absolute difference = −4.05% (95% CI = −5.58 to −2.41); OR = 0.69 (95% CI = 0.50 to 0.88)]. The 12-month disability rate was also lower in the MT group than the No-MT group [14.74% versus 19.41%; absolute difference = −5.70% (95% CI = −7.25 to −3.22); OR = 0.83 (95% CI = 0.70 to 0.95)]. Furthermore, the recurrence rate did not differ significantly between the MT and No-MT groups (p = 0.29).

Conclusion:

The study reveals that metformin use in stroke patients with T2DM results in a less severe stroke and lower fatality and disability rates.

A Clinical Perspective of the Multifaceted Mechanism of Metformin in Diabetes, Infections, Cognitive Dysfunction, and Cancer

In type 2 diabetes, ecological and lifecourse factors may interact with the host microbiota to influence expression of his/her genomes causing perturbation of interconnecting biological pathways with diverse clinical course. Metformin is a plant-based or plant-derived medicinal product used for the treatment of type 2 diabetes for over 60 years and is an essential drug listed by the World Health Organization. By reducing mitochondrial oxidative phosphorylation and adenosine triphosphate (ATP) production, metformin increased AMP (adenosine monophosphate)-activated protein kinase (AMPK) activity and altered cellular redox state with reduced glucagon activity, endogenous glucose production, lipogenesis, and protein synthesis. Metformin modulated immune response by directly reducing neutrophil to lymphocyte ratio and improving the phagocytic function of immune cells. By increasing the relative abundance of mucin-producing and short-chain-fatty-acid-producing gut microbes, metformin further improved the host inflammatory and metabolic milieu. Experimentally, metformin promoted apoptosis and reduced proliferation of cancer cells by reducing their oxygen consumption and modulating the microenvironment. Both clinical and mechanistic studies support the pluripotent effects of metformin on reducing cardiovascular–renal events, infection, cancer, cognitive dysfunction, and all-cause death in type 2 diabetes, making this low-cost medication a fundamental therapy for individualization of other glucose-lowering drugs in type 2 diabetes. Further research into the effects of metformin on cognitive function, infection and cancer, especially in people without diabetes, will provide new insights into the therapeutic value of metformin in our pursuit of prevention and treatment of ageing-related as well as acute and chronic diseases beyond diabetes.

Comparison of the effects on cardiovascular events between use of metformin and dipeptidyl peptidase-4 inhibitors as the first-line hypoglycaemic agents in Japanese patients with type 2 diabetes mellitus: a claims database analysis

OBJECTIVES

To compare the risk of cardiovascular events from the initiation of therapy between metformin and dipeptidyl peptidase-4 inhibitors (DPP-4i) as first-line therapy.

DESIGN

Retrospective cohort study using two claims databases.

SETTING

The MDV database (provided by Medical Data Vision) comprised data from acute care hospitals, and the JMDC database (provided by JMDC) comprised data from individuals covered by health insurance societies.

PARTICIPANTS

Those who were diagnosed with type 2 diabetes at ≥18 years, prescribed metformin or DPP-4i as the first-line hypoglycaemic agent, had medical records of ≥6 months before the index prescription and had available glycated haemoglobin (HbA1c) data for the period, including the index date and 30 days before it (defined as the baseline) were included. Those diagnosed with type 1 diabetes and/or a history of myocardial infarction (MI) or cerebrovascular diseases were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcomes were cumulative risks from Kaplan-Meier curves or HRs of patients prescribed metformin compared with DPP-4i. The primary endpoint was the diagnosis of MI or stroke associated with hospitalisation. Patient demographics, prescribed drugs and laboratory test values of HbA1c and estimated glomerular filtration rate at baseline were adjusted. The study period starting from the index included treatment after initial monotherapy.

RESULTS

Overall, 2089 and 6686 patients in the MDV database and 1506 and 3635 in the JMDC database were prescribed metformin and DPP-4i, respectively. The HR of the primary endpoint was 0.879 with no statistical significance (95% CI 0.534 to 1.448, p=0.613) in the MDV database, while it was significantly lower, 0.398 (95% CI 0.213 to 0.742, 0.004) in the JMDC database.

CONCLUSIONS

Patients who received metformin as first-line therapy may have reduced cardiovascular events than those receiving DPP-4i. This study conforms to previous Japanese database studies, despite the consideration of its limitation being an observational design.

The effect of select systemic medications on outcomes in diabetics with central retinal vein occlusion

BACKGROUND

Diabetes mellitus is a risk factor for central retinal vein occlusion (CRVO); however, it is unclear whether certain commonly used medications among diabetics or glycemic control impact visual outcomes in diabetic eyes with CRVO.

PURPOSE

To evaluate the effect of select systemic medications and glycemic control on presenting features, treatment burden, and outcomes in patients with diabetes who develop a central retinal vein occlusion (CRVO).

METHODS

Retrospective longitudinal cohort study at a single tertiary academic referral center from 2009-2017 investigating eyes of patients being treated for diabetes mellitus at CRVO onset. Eyes with a prior history of anti-vascular endothelial growth factor (anti-VEGF) therapy or laser treatment within the year prior to CRVO onset were excluded. Main outcomes and measures were visual acuity (VA), central subfield thickness (CST), cystoid macular edema (CME), and number of intravitreal injections and laser treatment throughout follow-up.

RESULTS

We identified 138 eyes of 138 participants who were diabetic at CRVO onset. Of these, 49% had an ischemic CRVO. Median follow-up time was 25.5 months. Fifty-five eyes (40%) had a HbA1c within 6 months of CRVO presentation. HbA1c was positively correlated with both presenting CST (p = 0.04) and presence of CME (p < 0.01). In all 138 eyes, mean presenting VA was 20/246, and mean final VA was 20/364. Better-presenting VA was significantly associated with aspirin 325 mg use (p = 0.04). Lower CST at presentation was significantly associated with metformin use (p = 0.02). Sitagliptin use at CRVO onset was associated with a lower prevalence of CME at final follow-up (p < 0.01). Lower final CST was significantly associated with glipizide use at CRVO onset (p = 0.01). There were no significant associations between systemic medications or HbA1c and treatment burden or final VA (p > 0.05).

CONCLUSION

Although aspirin 325 mg, metformin, sitagliptin, and glipizide were associated with better-presenting VA, lower-presenting CST, lower prevalence of macular edema at final visit, and lower final CST, respectively, none of these systemic agents or glycemic control were associated with decreased treatment burden or improved visual outcomes in diabetics with CRVO.

Medical therapies for prevention of cardiovascular and renal events in patients with atrial fibrillation and diabetes mellitus

Atrial fibrillation (AF), type 2 diabetes mellitus (DM), and chronic kidney disease (CKD) are three global epidemics with significant effects on morbidity and mortality. Diabetes is a risk factor for AF, and a risk factor for thromboembolism, comorbidity, and mortality when AF is present. The pathophysiology of diabetes-related AF and interrelationships with cardiovascular events and renal events is not fully understood but is in part related to structural, electrical, electromechanical, and autonomic remodelling. The current practice guidelines offer limited recommendations on the management of patients with AF (or risk of AF) and diabetes with its own heterogeneity for the prevention of cardiovascular and renal events. This document discusses possible clinical approaches for these patients. In the last decade, there have been major improvements for the prevention of stroke in AF patients with direct oral anticoagulants, which are preferable to vitamin K antagonists for stroke prevention in DM. Because of the increased risk rate for several cardiovascular adverse events in diabetic patients, a similar relative risk reduction generally translates into greater absolute risk reduction in the diabetic population. Recent trials with non-insulin diabetes drugs using glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors showed a significant reduction for the risk of major adverse cardiovascular events in patients with type 2 DM. Sodium-glucose cotransporter-2 inhibitors also showed a large reduction in hospitalization for heart failure and renal events, which need to be more completely evaluated in patients with AF. Mechanisms, risks, and optimal management of AF patients with DM who have or are under risk of developing heart failure or CKD are also discussed in this document. The benefits of medical therapies for these patients still need to be put into perspective, and gaps in evidence on some of these issues are likely to be addressed in future years.

Ischemic Stroke Risk Among Adult Brain Tumor Survivors: Evidence to Guide Practice

ABSTRACT

INTRODUCTION: Primary brain tumors are the leading cause of cancer mortality in the United States affecting approximately 90,000 Americans each year. A major complication for brain tumor survivors is acute ischemic stroke (AIS). Currently, there are limited research to provide guidelines for AIS prevention and management in adult brain tumor survivors. The purpose of this review is to discuss the most common risk factors for AIS in adult brain tumor survivors along with best evidence for assessment, screening, and strategies to prevent AIS in this population. METHODS: Relevant literature was identified by searching CINAHL and PubMed databases using the following keywords: "brain tumor survivors," "adults," "stroke," "risk factors," "guidelines," "prevention," and "management". Articles not pertaining to adult brain tumor survivors and AIS were excluded. RESULTS: The location of the tumor, dose, extent, and type of radiation contribute to the development of vascular injury and subsequent carotid stenosis among brain tumor survivors. Endothelial growth factor inhibitor and chemotherapy drugs induces vascular remodeling. Other symptoms such as neurological impairments and co-morbidities are also present among brain tumor survivors. Furthermore, AIS increases from the time of primary brain tumor diagnosis and incidence further increases among patients who were diagnosed with a brain tumor as a child. CONCLUSION: Nurses play a key role in the assessment, prevention, and identifying individuals who are at risk of AIS during brain tumor survivorship. Engaging patients and their caregivers on minimizing their risks of AIS is crucial in the outpatient setting. Annual surveillance visits that include intracranial artery imaging should be used to identify individuals considered most at risk for developing AIS symptoms.

Prestroke Metformin Use on the 1-Year Prognosis of Intracerebral Hemorrhage Patients with Type 2 Diabetes

Background

Although recent studies have focused on the use of metformin in treating ischemic stroke, there is little literature to support whether it can treat intracerebral hemorrhage (ICH). Therefore, this study is aimed at evaluating the possible effects of prestroke metformin (MET) on ICH patients with type 2 diabetes.

Methods

From January 2010 to December 2019, all first-ever ICH patients with type 2 diabetes from our hospitals were included. All discharged patients would receive a one-time follow-up at 1 year after admission. Death, disability, and recurrence events were recorded.

Results

We included 730 patients for analysis (the median age: 65 [IQR, 56-72] years and 57.7% was men). Of those patients, 281 (38.5%) had received MET before ICH (MET+), whereas 449 (61.5%) had not (MET−). MET (+) patients had a lower median baseline hematoma volume than did MET (-) patients (9.6 ml [IQR, 5.3-22.4 ml] vs. 14.7 ml [IQR, 7.9-28.6 ml]; P < 0.001). The inhospital mortality events were not significantly reduced in the MET (+) group compared with the MET (-) group (6.4% vs 8.9%, respectively; absolute difference, −2.5% [95% CI, −3.9% to −0.7%]; OR, 0.70 [95% CI, 0.39 to 1.27]; P = 0.22). The 1-year mortality events were not significantly reduced in the MET (+) group compared with the MET (-) group (14.1% vs 17.4%, respectively; absolute difference, −3.3% [95% CI, −5.1% to −1.8%]; OR, 0.73 [95% CI, 0.47 to 1.14]; P = 0.16). The 1-year disability events were not significantly reduced in the MET (+) group compared with the MET (-) group (28.4% vs 34.1%, respectively; absolute difference, −5.7% [95% CI, −8.2% to −3.3%]; OR, 0.77 [95% CI, 0.52 to 1.13]; P = 0.18). Finally, the recurrence rates in those two groups were not significantly different (MET [+] vs. MET [-]: 6.4% vs. 5.9%; absolute difference, 0.5% [95% CI, 0.2% to 1.3%]; OR, 1.08 [95% CI, 0.51 to 2.28]; P = 0.84).

Conclusions

Pre-ICH metformin use was not associated with inhospital mortality and 1-year prognosis in diabetic ICH patients.

Metformin Prevents Hyperglycemia-Associated, Oxidative Stress-Induced Vascular Endothelial Dysfunction: Essential Role for the Orphan Nuclear Receptor Human Nuclear Receptor 4A1 (Nur77)

Vascular pathology is increased in diabetes because of reactive-oxygen-species (ROS)-induced endothelial cell damage. We found that in vitro and in a streptozotocin diabetes model in vivo, metformin at diabetes-therapeutic concentrations (1-50 µM) protects tissue-intact and cultured vascular endothelial cells from hyperglycemia/ROS-induced dysfunction typified by reduced agonist-stimulated endothelium-dependent, nitric oxide-mediated vasorelaxation in response to muscarinic or proteinase-activated-receptor 2 agonists. Metformin not only attenuated hyperglycemia-induced ROS production in aorta-derived endothelial cell cultures but also prevented hyperglycemia-induced endothelial mitochondrial dysfunction (reduced oxygen consumption rate). These endothelium-protective effects of metformin were absent in orphan-nuclear-receptor Nr4a1-null murine aorta tissues in accord with our observing a direct metformin-Nr4a1 interaction. Using in silico modeling of metformin-NR4A1 interactions, Nr4a1-mutagenesis, and a transfected human embryonic kidney 293T cell functional assay for metformin-activated Nr4a1, we identified two Nr4a1 prolines, P505/P549 (mouse sequences corresponding to human P501/P546), as key residues for enabling metformin to affect mitochondrial function. Our data indicate a critical role for Nr4a1 in metformin's endothelial-protective effects observed at micromolar concentrations, which activate AMPKinase but do not affect mitochondrial complex-I or complex-III oxygen consumption rates, as does 0.5 mM metformin. Thus, therapeutic metformin concentrations requiring the expression of Nr4a1 protect the vasculature from hyperglycemia-induced dysfunction in addition to metformin's action to enhance insulin action in patients with diabetes. SIGNIFICANCE STATEMENT: Metformin improves diabetic vasodilator function, having cardioprotective effects beyond glycemic control, but its mechanism to do so is unknown. We found that metformin at therapeutic concentrations (1-50µM) prevents hyperglycemia-induced endothelial dysfunction by attenuating reactive oxygen species-induced damage, whereas high metformin (>250 µM) impairs vascular function. However, metformin's action requires the expression of the orphan nuclear receptor NR4A1/Nur77. Our data reveal a novel mechanism whereby metformin preserves diabetic vascular endothelial function, with implications for developing new metformin-related therapeutic agents.

Comparative assessment of in vitro BBB tight junction integrity following exposure to cigarette smoke and e-cigarette vapor: a quantitative evaluation of the protective effects of metformin using small-molecular-weight paracellular markers

Background

The blood–brain barrier (BBB) plays a critical role in protecting the central nervous system (CNS) from blood-borne agents and potentially harmful xenobiotics. Our group’s previous data has shown that tobacco smoke (TS) and electronic cigarettes (EC) affect the BBB integrity, increase stroke incidence, and are considered a risk factor for multiple CNS disorders. Metformin was also found to abrogate the adverse effects of TS and EC.

Methods

We used sucrose and mannitol as paracellular markers to quantitatively assess TS and EC’s impact on the BBB in-vitro. Specifically, we used a quantitative platform to determine the harmful effects of smoking on the BBB and study the protective effect of metformin. Using a transwell system and iPSCs-derived BMECs, we assessed TS and EC’s effect on sucrose and mannitol permeability with and without metformin pre-treatment at different time points. Concurrently, using immunofluorescence (IF) and Western blot (WB) techniques, we evaluated the expression and distribution of tight junction proteins, including ZO-1, occludin, and claudin-5.

Results

Our data showed that TS and EC negatively affect sucrose and mannitol permeability starting after 6 h and up to 24 h. The loss of barrier integrity was associated with a reduction of TEER values. While the overall expression level of ZO-1 and occludin was not significantly downregulated, the distribution of ZO-1 was altered, and discontinuation patterns were evident through IF imaging. In contrast to occludin, claudin-5 expression was significantly decreased by TS and EC, as demonstrated by WB and IF data.

Conclusion

In agreement with previous studies, our data showed the metformin could counteract the negative impact of TS and EC on BBB integrity, thus suggesting the possibility of repurposing this drug to afford cerebrovascular protection.

Metforminin tek başına veya valproik asit ile beraber farelerde pentilentetrazol ile indüklenen nöbetler üzerine koruyucu etkisi

Amaç: Bu çalışmanın amacı, metforminin pentilentetrazol (PTZ) ile indüklenen nöbet davranışı üzerindeki etkilerini ve nöronal hasar üzerindeki nöroprotektif etkisini araştırmaktır. Gereç ve Yöntemler: 35-38 g ağırlığındaki otuz beş (35) Erkek BALB-c Albino fare rastgele beş gruba ayrıldı. Kontrol grubu, PTZ; PTZ enjekte edildi, VPA (200 mg / kg i.p.), Metformin (200 mg / kg i.p.) ve VPA + Metformin. Pentilentetrazol (PTZ) (60 mg / kg, i.p.), nöbetleri indüklemek için ilaç enjeksiyonundan 30 dakika sonra enjekte edildi ve nöbet aşamaları ve davranışsal skorlama değerlendirildi. İşlem tamamlandıktan sonra beyin dokuları çıkarıldı ve biyokimyasal ve histopatolojik prosedürlerle analiz edildi. Hipokampal Cornu Ammonis (CA) 1, CA2, CA3 ve DG (dentat girus) bölgeleri histopatolojik olarak değerlendirildi ve oksidatif stres belirteçleri (toplam antioksidan durum (TAS), toplam oksidan durum (TOS) ölçüldü. Bulgular: PTZ grubuyla karşılaştırıldığında, Metformin tek başına FMJ başlangıç süresini etkilemedi, ancak VPA ve Metformin kombinasyonu FMJ başlangıç süresini anlamlı derecede artırdığı gözlendi (p

Metformin prevents stroke damage in non-diabetic female mice with chronic kidney disease

Chronic kidney disease (CKD) worsens ischemic stroke severity in both patients and animals. In mice, these poorer functional outcomes are associated with decreased brain activity of AMP-activated protein kinase (AMPK), a molecule that recently emerged as a potential therapeutic target for ischemic stroke. The antidiabetic drug metformin, a well-known activator of AMPK, has improved stroke outcomes in diabetic patients with normal renal function. We investigated whether chronic metformin pre-conditioning can rescue AMPK activity and prevent stroke damage in non-diabetic mice with CKD. Eight-week-old female C57BL/6J mice were assigned to CKD or SHAM groups. CKD was induced through right kidney cortical electrocautery, followed by left total nephrectomy. Mice were then allocated to receive metformin (200 mg/kg/day) or vehicle for 5 weeks until stroke induction by transient middle cerebral artery occlusion (tMCAO). The infarct volumes were lower in CKD mice exposed to metformin than in vehicle-treated CKD mice 24 h after tMCAO. Metformin pre-conditioning of CKD mice improved their neurological score, grip strength, and prehensile abilities. It also enhanced AMPK activation, reduced apoptosis, increased neuron survival and decreased microglia/macrophage M1 signature gene expression as well as CKD-induced activation of the canonical NF-κB pathway in the ischemic lesions of CKD mice.

Omentin-1: Protective impact on ischemic stroke via ameliorating atherosclerosis

Omentin-1, a newly identified adipokine, has recently been revealed as a novel biomarker for ischemic stroke (IS). Low circulating omentin-1 levels could indicate a high risk of IS, and elevated omentin-1 levels exert a favorable impact on cerebral ischemia. Furthermore, omentin-1 has anti-atherosclerotic, anti-inflammatory, and cardiovascular protective capabilities through the intracellular Akt/AMP-activated protein kinase (AMPK)/ nuclear factor-κB (NF-κB) and certain protein kinase (ERK, JNK, and p38) signaling pathways. Omentin-1 also alleviates endothelial cell dysfunction, improves revascularization via the Akt-endothelial nitric-oxide synthase (eNOS) regulatory axis, promotes endothelium-dependent vasodilation through endothelium-derived NO in an eNOS fashion, and inhibits VSMC proliferation by means of AMPK/ERK signaling pathways, VSMC migration via inactivation of the NADPH oxidase (NOX)/ROS/p38/HSP27 pathways and artery calcification via the PI3K-Akt pathway. These findings indicate that omentin-1 may be a negative mediator of IS. Pharmacologically, several lines of clinical evidence indicate that metformin and statins could elevate omentin-1 levels, although the specific mechanism has not been precisely delineated until now. This study is the first to summarize the comprehensive mechanisms between omentin-1 and atherosclerosis and to review the shielding effect of omentin-1 on IS. We shed light on omentin-1 as a novel therapeutic target for combating IS.

Effects of metformin on atrial and ventricular arrhythmias: evidence from cell to patient

Metformin has been shown to have various cardiovascular benefits beyond its antihyperglycemic effects, including a reduction in stroke, heart failure, myocardial infarction, cardiovascular death, and all-cause mortality. However, the roles of metformin in cardiac arrhythmias are still unclear. It has been shown that metformin was associated with decreased incidence of atrial fibrillation in diabetic patients with and without myocardial infarction. This could be due to the effects of metformin on preventing the structural and electrical remodeling of left atrium via attenuating intracellular reactive oxygen species, activating 5′ adenosine monophosphate-activated protein kinase, improving calcium homeostasis, attenuating inflammation, increasing connexin-43 gap junction expression, and restoring small conductance calcium-activated potassium channels current. For ventricular arrhythmias, in vivo reports demonstrated that activation of 5′ adenosine monophosphate-activated protein kinase and phosphorylated connexin-43 by metformin played a key role in ischemic ventricular arrhythmias reduction. However, metformin failed to show anti-ventricular arrhythmia benefits in clinical trials. In this review, in vitro and in vivo reports regarding the effects of metformin on both atrial arrhythmias and ventricular arrhythmias are comprehensively summarized and presented. Consistent and controversial findings from clinical trials are also summarized and discussed. Due to limited numbers of reports, further studies are needed to elucidate the mechanisms and effects of metformin on cardiac arrhythmias. Furthermore, randomized controlled trials are needed to clarify effects of metformin on cardiac arrhythmias in human.

Comparison of Effects of Metformin, Phenformin, and Inhibitors of Mitochondrial Complex I on Mitochondrial Permeability Transition and Ischemic Brain Injury

Damage to cerebral mitochondria, particularly opening of mitochondrial permeability transition pore (MPTP), is a key mechanism of ischemic brain injury, therefore, modulation of MPTP may be a potential target for a neuroprotective strategy in ischemic brain pathologies. The aim of this study was to investigate whether biguanides-metformin and phenformin as well as other inhibitors of Complex I of the mitochondrial electron transfer system may protect against ischemia-induced cell death in brain slice cultures by suppressing MPTP, and whether the effects of these inhibitors depend on the age of animals. Experiments were performed on brain slice cultures prepared from 5-7-day (premature) and 2-3-month old (adult) rat brains. In premature brain slice cultures, simulated ischemia (hypoxia plus deoxyglucose) induced necrosis whereas in adult rat brain slice cultures necrosis was induced by hypoxia alone and was suppressed by deoxyglucose. Phenformin prevented necrosis induced by simulated ischemia in premature and hypoxia-induced-in adult brain slices, whereas metformin was protective in adult brain slices cultures. In premature brain slices, necrosis was also prevented by Complex I inhibitors rotenone and amobarbital and by MPTP inhibitor cyclosporine A. The latter two inhibitors were protective in adult brain slices as well. Short-term exposure of cultured neurons to phenformin, metformin and rotenone prevented ionomycin-induced MPTP opening in intact cells. The data suggest that, depending on the age, phenformin and metformin may protect the brain against ischemic damage possibly by suppressing MPTP via inhibition of mitochondrial Complex I.

2020 Consensus of Taiwan Society of Cardiology on the pharmacological management of patients with type 2 diabetes and cardiovascular diseases

The global incidence and prevalence of type 2 diabetes have been escalating in recent decades. The total diabetic population is expected to increase from 415 million in 2015 to 642 million by 2040. Patients with type 2 diabetes have an increased risk of atherosclerotic cardiovascular disease (ASCVD). About two-thirds of patients with type 2 diabetes died of ASCVD. The association between hyperglycemia and elevated cardiovascular (CV) risk has been demonstrated in multiple cohort studies. However, clinical trials of intensive glucose reduction by conventional antidiabetic agents did not significantly reduce macrovascular outcomes.In December 2008, U.S. Food and Drug Administration issued a mandate that every new antidiabetic agent requires rigorous assessments of its CV safety. Thereafter, more than 200,000 patients have been enrolled in a number of randomized controlled trials (RCTs). These trials were initially designed to prove noninferiority. It turned out that some of these trials demonstrated superiority of some new antidiabetic agents versus placebo in reducing CV endpoints, including macrovascular events, renal events, and heart failure. These results are important in clinical practice and also provide an opportunity for academic society to formulate treatment guidelines or consensus to provide specific recommendations for glucose control in various CV diseases.In 2018, the Taiwan Society of Cardiology (TSOC) and the Diabetes Association of Republic of China (DAROC) published the first joint consensus on the "Pharmacological Management of Patients with Type 2 Diabetes and Cardiovascular Diseases." In 2020, TSOC appointed a new consensus group to revise the previous version. The updated 2020 consensus was comprised of 5 major parts: (1) treatment of diabetes in patients with multiple risk factors, (2) treatment of diabetes in patients with coronary heart disease, (3) treatment of diabetes in patients with stage 3 chronic kidney disease, (4) treatment of diabetes in patients with a history of stroke, and (5) treatment of diabetes in patients with heart failure. The members of the consensus group thoroughly reviewed all the evidence, mainly RCTs, and also included meta-analyses and real-world evidence. The treatment targets of HbA1c were finalized. The antidiabetic agents were ranked according to their clinical evidence. The consensus is not mandatory. The final decision may need to be individualized and based on clinicians' discretion.

Novel potent antiplatelet thrombotic agent derived from biguanide for ischemic stroke

Platelet thrombosis is the main pathogeny resulting in the low curability of ischemic stroke, a leading cause of mortality and disability worldwide. Metformin, a biguanide derivative that is the first-line oral medicine for type 2 diabetes, alleviates the severity of ischemic stroke in diabetic patients and suppresses platelet activation in experimental animal model. However, the clinical implementation of commercial biguanide analogs for stroke related to platelet thrombosis remains challenging due to its weak potency, poor pharmacokinetic characteristics and possible hypoglycemia. Here, twenty-three biguanide derivatives were designed and synthesized based on the principles of bioisosteres. These derivatives were evaluated for the activity of antiplatelet thrombosis in vivo. We found that N-trifluoromethanesulfonyl biguanide derivative, compound b10, uniquely prevented cerebral infarction as well as neuronal function injury, and significantly decrease the mortality rate of ischemic stroke in the middle cerebral artery occlusion mice without significant side effects. We verified that b10 directly inhibited platelets thrombus formation and decreased the compactness of stroke thrombi. Particularly, b10 exhibited good potency to inhibit human platelet activation including platelet aggregation, adhesion, pseudopodia formation, integrin GPIIb/IIIa activation, CD62P expression and clot retraction. Meanwhile, the pharmacokinetics assessment showed that b10 had satisfying pharmacological characteristics including a longer duration and a higher oral absorption ratio than its parent compound. In addition, b10 remarkably ameliorated not only stroke related to platelet thrombosis but also carotid artery thrombus formation. It is concluded that the novel potent antiplatelet thrombotic agent derived from biguanide is a promising candidate for stroke treatment.

Could metformin be therapeutically useful in Huntington's disease?

Emerging evidence suggest that dimethylbiguanide (metformin), a first-line drug for type 2 diabetes mellitus, could be neuroprotective in a range of brain pathologies, which include neurodegenerative diseases and brain injury. However, there are also contraindications that associate metformin treatment with cognitive impairment as well as adverse outcomes in Alzheimer's disease and Parkinson's disease animal models. Recently, a beneficial effect of metformin in animal models of Huntington's disease (HD) has been strengthened by multiple reports. In this brief review, the findings associated with the effects of metformin in attenuating neurodegenerative diseases are discussed, focusing on HD-associated pathology and the potential underlying mechanisms highlighted by these studies. The mechanism of action of metformin is complex, and its therapeutic efficacy is therefore expected to be dependent on the disease context. The key metabolic pathways that are effectively affected by metformin, such as AMP-activated protein kinase activation, may be altered in the later decades of the human lifespan. In this regard, metformin may nonetheless be therapeutically useful for neurological diseases with early pathological onsets, such as HD.

Cardiovascular risk following metformin treatment in patients with type 2 diabetes mellitus: Results from meta-analysis

AIM

Pharmacologic therapy for T2DM has proven benefits in terms of reducing elevated blood glucose levels and reducing microvascular complications. However, the impact of metformin on adverse cardiovascular outcomes and cardiovascular mortality is less clear. We carried out this meta-analysis on all published studies to estimate the overall cardiovascular risk following metformin treatment in patients with T2DM.

METHODS

We searched the PubMed, Embase and CNKI (China National Knowledge Infrastructure) databases for all articles. The odds ratio (OR) corresponding to the 95% confidence interval (95% CI) was used to assess the cardiovascular risk following metformin treatment in patients with T2DM. The statistical heterogeneity among studies was assessed with the Q-test and I² statistics.

RESULTS

We collected 16 studies including 25 comparisons with 1,160,254 patients of type 2 diabetes mellitus and 701,843 patients of T2DM following metformin treatment. Our results found statistical evidence of significantly decreased cardiovascular risk to be associated with following treatment with metformin in patients with type 2 diabetes mellitus (OR = 0.57, 95% CI = 0.48-0.68) (shown in Table 1 and Fig. 2), both with the mortality (OR = 0.44, 95% CI = 0.34-0.57) and incidence (OR = 0.73, 95% CI = 0.59-0.90).

CONCLUSIONS

Our meta-analysis indicated that following metformin treatment in patients with T2DM was associated with decreased cardiovascular risk, both with the mortality and incidence. However, the heterogeneity among studies may potentially affect the final results.

Metformin reduces neuronal damage and promotes neuroblast proliferation and differentiation in a cerebral ischemia/reperfusion rat model

According to the previous research, metformin, a medication utilized for type 2 diabetes management, inhibits neural aging and reduces infarct size by enhancing angiogenesis in a mouse stroke model. What is more, metformin administration also promotes neural precursor cells proliferation, migration, as well as differentiation for newborn mice with hypoxia-ischemia brain injury. However, whether metformin regulates neurogenesis in an adult rat ischemia/reperfusion (I/R) model remains unclear. The current research found that metformin administration reduced neuronal damage in the CA1 area of hippocampus in a rat model of I/R. The number of neuronal nuclei positive neuron was significantly increased and glial fibrillary acidic protein positive astrocyte became obviously declined in the CA1 region in I/R rats treated with metformin. It was further demonstrated that metformin promoted neuroblasts proliferation and neuronal differentiation in the subgranular zone of the dentate gyrus and inhibited the formation of astrocyte. Our study indicates that activation of endogenous neuroblasts using metformin will become a favorable target in therapeutic intervention of cerebral ischemia injury models.

Do most patients with obesity or type 2 diabetes, and atrial fibrillation, also have undiagnosed heart failure? A critical conceptual framework for understanding mechanisms and improving diagnosis and treatment

Obesity and diabetes can lead to heart failure with preserved ejection fraction (HFpEF), potentially because they both cause expansion and inflammation of epicardial adipose tissue and thus lead to microvascular dysfunction and fibrosis of the underlying left ventricle. The same process also causes an atrial myopathy, which is clinically evident as atrial fibrillation (AF); thus, AF may be the first manifestation of HFpEF. Many patients with apparently isolated AF have latent HFpEF or subsequently develop HFpEF. Most patients with obesity or diabetes who have AF and exercise intolerance have increased left atrial pressures at rest or during exercise, even in the absence of diagnosed HFpEF. Among patients with AF, those who also have latent HFpEF have increased risk for systemic thromboembolism and death. The identification of HFpEF in patients with obesity or diabetes alters the risk-to-benefit relationship of commonly prescribed treatments. Bariatric surgery and statins can ameliorate AF and reduce the risk for HFpEF. Conversely, antihyperglycaemic drugs that promote adipogenesis or cause sodium retention (insulin and thiazolidinediones) may increase the risk for heart failure in patients with an underlying ventricular myopathy. Patients with obesity and diabetes who undergo catheter ablation for AF are at increased risk for AF recurrence and for post-ablation increases in pulmonary venous pressures and worsening heart failure, especially if HFpEF coexists. Therefore, AF may be the earliest indicator of HFpEF in patients with obesity or type 2 diabetes, and recognition of HFpEF alters the management of these patients.

Metformin Protects against Oxidative Stress Injury Induced by Ischemia/Reperfusion via Regulation of the lncRNA-H19/miR-148a-3p/Rock2 Axis

Previous studies have shown that metformin not only is a hypoglycemic agent but also has neuroprotective effects. However, the mechanism of action of metformin in ischemic stroke is unclear. Oxidative stress is an important factor in the pathogenesis of cerebral ischemia-reperfusion injury. It has been reported that metformin is associated with stroke risk in the clinical population. This study is aimed at investigating the effect and mechanism of metformin in an experimental model of oxidative stress induced by ischemia/reperfusion (I/R) in vivo and oxygen glucose deprivation/reperfusion (OGD/R) in vitro. Metformin (100, 200, and 300 mg/kg) was administered intraperitoneally immediately after induction of cerebral ischemia. The indicators of oxidative stress selected were antioxidant enzyme activities of catalase, malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), and glutathione peroxidation enzyme (GSHPx). First, we demonstrated that metformin can significantly alleviate acute and chronic cerebral I/R injury and it has a strong regulatory effect on stroke-induced oxidative stress. It can reduce the elevated activities of MDA and NO and increase the levels of GSHPx and SOD in the cerebrum of mice and N2a cells exposed to I/R. Furthermore, real-time PCR and western blot were used to detect the expression of long noncoding RNA H19 (lncRNA-H19), microRNA-148a-3p (miR-148a-3p), and Rho-associated protein kinase 2 (Rock2). The direct interaction of lncRNA-H19, miR-148a-3p, and Rock2 was tested using a dual luciferase reporter assay. lncRNA-H19 altered OGD/R-induced oxidative stress by modulating miR-148a-3p to increase Rock2 expression. The expression of lncRNA-H19 and Rock2 could be downregulated with metformin in vivo and in vitro. In conclusion, our study confirmed that metformin exerts neuroprotective effects by regulating ischemic stroke-induced oxidative stress injury via the lncRNA-H19/miR-148a-3p/Rock2 axis. These results provide new evidence that metformin may represent a potential treatment for stroke-related brain injury.

Is the use of metformin in patients undergoing dialysis hazardous for life? A systematic review of the safety of metformin in patients undergoing dialysis

AIMS

Metformin may have clinical benefits in dialysis patients; however, its safety in this population is unknown. This systematic review evaluated the safety of metformin in dialysis patients.

METHODS

MEDLINE, Embase, CENTRAL, PsycINFO and the Cochrane Library were searched for randomised controlled trials and observational studies evaluating metformin use in dialysis patients. Three authors reviewed the studies and extracted data. The primary outcomes were mortality, occurrence of lactic acidosis and myocardial infarction (MI) in patients taking metformin during dialysis treatment for ≥12 months (long term). Risk of bias was assessed using Risk Of Bias In Nonrandomised Studies of Interventions (ROBINS-1). Overall quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Fifteen observational studies were eligible; 7 were prospective observational studies and 8 were case reports/case series. No randomised controlled trials were identified. The 7 prospective observational studies (n = 194) reported on cautious metformin use in patients undergoing maintenance dialysis. Only 3 provided long-term follow-up data. In 2 long-term studies of metformin therapy (≤1000 mg/d) in patients undergoing peritoneal dialysis (PD), 1 reported 6 deaths (6/83; 7%) due to major cardiovascular events (3 MI) and the other reported no deaths (0/35). One long-term study of metformin therapy (250 mg to 500 mg thrice weekly) in patients undergoing haemodialysis reported 4 deaths (4/61; 7%) due to major cardiovascular events (2 MI). These findings provide very low-quality evidence as they come from small observational studies.

CONCLUSION

The evidence regarding the safety of metformin in people undergoing dialysis is inconclusive. Appropriately designed randomised controlled trials are needed to resolve this uncertainty.

Metformin decreases hyaluronan synthesis by vascular smooth muscle cells

Metformin is the first-line drug in the treatment of type 2 diabetes worldwide based on its effectiveness and cardiovascular safety. Currently metformin is increasingly used during pregnancy in women with gestational diabetes mellitus, even if the long-term effects of metformin on offspring are not exactly known. We have previously shown that high glucose concentration increases hyaluronan (HA) production of cultured human vascular smooth muscle cells (VSMC) via stimulating the expression of hyaluronan synthase 2 (HAS2). This offers a potential mechanism whereby hyperglycemia leads to vascular macroangiopathy. In this study, we examined whether gestational metformin use affects HA content in the aortic wall of mouse offspring in vivo. We also examined the effect of metformin on HA synthesis by cultured human VSMCs in vitro. We found that gestational metformin use significantly decreased HA content in the intima-media of mouse offspring aortas. In accordance with this, the synthesis of HA by VSMCs was also significantly decreased in response to treatment with metformin. This decrease in HA synthesis was shown to be due to the reduction of both the expression of HAS2 and the amount of HAS substrates, particularly UDP-N-acetylglucosamine. As shown here, gestational metformin use is capable to program reduced HA content in the vascular wall of the offspring strongly supporting the idea, that metformin possesses long-term vasculoprotective effects.

Heightened risk of intensive rate control in patients with atrial fibrillation who are obese or have type 2 diabetes: A critical review and re-evaluation

Atrial fibrillation (AF) is common in patients with obesity and diabetes; the arrhythmia (if long-standing) is typically managed by rate control and anticoagulation. However, the coexistence of these two metabolic disorders complicates therapeutic options for rate control. The likely pathogenesis of AF in these patients is an expansion of epicardial adipose tissue whose inflammation is transmitted to the left atrium causing electromechanical remodeling. However, this same process is also transmitted to the left ventricle (LV), impairing its distensibility and its ability to tolerate volume, leading to heart failure with preserved ejection fraction. Unfortunately, the latter diagnosis (although commonly present in patients with AF and a coexistent metabolic disorder) is often ignored. To achieve rate control, physicians prescribe intensive treatment with atrioventricular (AV) nodal-blocking drugs, often at doses that are titrated to blunt exercise as well as resting heart rate responses. However, strict rate control (target rate, <80/min) is associated with somewhat worse outcomes than lenient rate control (target rate, <110/min). Furthermore, any rate slowing that facilitates diastolic filling may aggravate filling pressures that are already disproportionately increased because the LV is stiff and overfilled as a result of cardiac inflammation. Rate slowing in AF with beta blockers may not achieve the benefit expected from the blockade of adrenergically mediated cardiotoxicity, and some AV nodal-blocking drugs (digoxin and dronedarone) can increase the risk of death in patients with AF. Finally, cardiac fibrosis in obesity and diabetes may affect the conduction system, which can predispose to serious bradyarrhythmias if patients are prescribed AV nodal-blocking drugs.

Mechanisms of action of metformin with special reference to cardiovascular protection

Management guidelines continue to identify metformin as initial pharmacologic antidiabetic therapy of choice for people with type 2 diabetes without contraindications, despite recent randomized trials that have demonstrated significant improvements in cardiovascular outcomes with newer classes of antidiabetic therapies. The purpose of this review is to summarize the current state of knowledge of metformin's therapeutic actions on blood glucose and cardiovascular clinical evidence and to consider the mechanisms that underlie them. The effects of metformin on glycaemia occur mainly in the liver, but metformin-stimulated glucose disposal by the gut has emerged as an increasingly import site of action of metformin. Additionally, metformin induces increased secretion of GLP-1 from intestinal L-cells. Clinical cardiovascular protection with metformin is supported by three randomized outcomes trials (in newly diagnosed and late stage insulin-treated type 2 diabetes patients) and a wealth of observational data. Initial evidence suggests that cotreatment with metformin may enhance the impact of newer incretin-based therapies on cardiovascular outcomes, an important observation as metformin can be combined with any other antidiabetic agent. Multiple potential mechanisms support the concept of cardiovascular protection with metformin beyond those provided by reduced blood glucose, including weight loss, improvements in haemostatic function, reduced inflammation, and oxidative stress, and inhibition of key steps in the process of atherosclerosis. Accordingly, metformin remains well placed to support improvements in cardiovascular outcomes, from diagnosis and throughout the course of type 2 diabetes, even in this new age of improved outcomes in type 2 diabetes.

Association of Antihyperglycemic Therapy with Risk of Atrial Fibrillation and Stroke in Diabetic Patients

Type 2 diabetes mellitus (DM) is associated with an increased risk of cardiovascular disease (CVD). Atrial fibrillation (AF) and stroke are both forms of CVD that have major consequences in terms of disabilities and death among patients with diabetes; however, they are less present in the preoccupations of scientific researchers as a primary endpoint of clinical trials. Several publications have found DM to be associated with a higher risk for both AF and stroke; some of the main drugs used for glycemic control have been found to carry either increased, or decreased risks for AF or for stroke in DM patients. Given the risk for thromboembolic cerebrovascular events seen in AF patients, the question arises as to whether stroke and AF occurring with modified incidences in diabetic individuals under therapy with various classes of antihyperglycemic medications are interrelated and should be considered as a whole. At present, the medical literature lacks studies specifically designed to investigate a cause-effect relationship between the incidences of AF and stroke driven by different antidiabetic agents. In default of such proof, we reviewed the existing evidence correlating the major classes of glucose-controlling drugs with their associated risks for AF and stroke; however, supplementary proof is needed to explore a hypothetically causal relationship between these two, both of which display peculiar features in the setting of specific drug therapies for glycemic control.

Metformin decreases the risk of sudden sensorineural hearing loss in patients with diabetes mellitus: A 14-year follow-up study

BACKGROUND

The risk of sudden sensorineural hearing loss associated with metformin use in patients with diabetes mellitus has not been fully examined.

STUDY DESIGN

It is a retrospective matched-cohort study.

SUBJECTS AND METHODS

We examined the medical records of patients with diabetes mellitus over 18 years old in Taiwan's National Health Insurance Research Database for the period between 1 January 2000 and 31 December 2013, to establish matched cohorts (14,109 with and 42,327 without metformin use) at a ratio of 1:3 by sex, age and index year.

RESULTS

We used a Cox regression hazard model to identify risk factors of sudden sensorineural hearing loss during 14 years of follow-up, and the results indicate that a significantly lower percentage of diabetes mellitus patients with metformin use (p = 0.033) developed sudden sensorineural hearing loss compared with those without metformin use (0.21%, 29/14,109 vs 0.32%, 136/42,327). After adjustment for age and other variables [adjusted hazard ratio: 0.630 (95% confidence interval: 0.422-0.941, p = 0.024)], this study also demonstrated that metformin use appeared to reduce the risk of developing sudden sensorineural hearing loss.

CONCLUSION

This study demonstrated an association between metformin use and lower incidence of sudden sensorineural hearing loss among patients with diabetes mellitus.

Gender Differences and Risk Factors of Recurrent Stroke in Type 2 Diabetic Malaysian Population with History of Stroke: The Observation from Malaysian National Neurology Registry

BACKGROUND AND PURPOSE

Diabetes mellitus has been reported as a strong independent risk factor for stroke recurrence. Data on the modifiable factors contributing to the recurrence of stroke in type 2 diabetic Malaysian population with a history of stroke stratified by genders are lacking, and this supports the importance of this study.

METHOD

The data of 4622 patients with T2DM who had a history of stroke was obtained from the Malaysian National Stroke Registry. Univariate analysis was performed to differentiate between genders with and without stroke recurrence in terms of demographics, first stroke attack presentations, and other clinical characteristics. The significant factors determined from the univariate analysis were further investigated using logistic regression.

RESULTS

Ischemic heart diseases were found significantly associated with the stroke recurrence in males (OR = 1.738; 95% CI: 1.071-2.818) as well as female (OR = 5.859; 95% CI: 2.469-13.752) diabetic patients. The duration of hypertension, as well as the duration of diabetes, has been associated with the recurrence in both male and female subjects (p value < 0.05). Smoking status has an impact on the stroke recurrence in male subjects, while no significant association was observed among their peers.

CONCLUSIONS

Most of the predictive factors contributing to the recurrence of stroke in type 2 diabetic Malaysian population with a history of stroke are modifiable, in which IHD was the most prominent risk factor in both genders. The impact of optimizing the management of IHD as well as blood glucose control on stroke recurrence may need to be elucidated. No major differences in recurrent stroke predictors were seen between genders among the Malaysian population with type 2 diabetes mellitus who had a previous history of stroke.

Resveratrol Preconditioning Induces Genomic and Metabolic Adaptations within the Long-Term Window of Cerebral Ischemic Tolerance Leading to Bioenergetic Efficiency

Neuroprotective agents administered post-cerebral ischemia have failed so far in the clinic to promote significant recovery. Thus, numerous efforts were redirected toward prophylactic approaches such as preconditioning as an alternative therapeutic strategy. Our laboratory has revealed a novel long-term window of cerebral ischemic tolerance mediated by resveratrol preconditioning (RPC) that lasts for 2 weeks in mice. To identify its mediators, we conducted an RNA-seq experiment on the cortex of mice 2 weeks post-RPC, which revealed 136 differentially expressed genes. The majority of genes (116/136) were downregulated upon RPC and clustered into biological processes involved in transcription, synaptic signaling, and neurotransmission. The downregulation in these processes was reminiscent of metabolic depression, an adaptation used by hibernating animals to survive severe ischemic states by downregulating energy-consuming pathways. Thus, to assess metabolism, we used a neuronal-astrocytic co-culture model and measured the cellular respiration rate at the long-term window post-RPC. Remarkably, we observed an increase in glycolysis and mitochondrial respiration efficiency upon RPC. We also observed an increase in the expression of genes involved in pyruvate uptake, TCA cycle, and oxidative phosphorylation, all of which indicated an increased reliance on energy-producing pathways. We then revealed that these nuclear and mitochondrial adaptations, which reduce the reliance on energy-consuming pathways and increase the reliance on energy-producing pathways, are epigenetically coupled through acetyl-CoA metabolism and ultimately increase baseline ATP levels. This increase in ATP would then allow the brain, a highly metabolic organ, to endure prolonged durations of energy deprivation encountered during cerebral ischemia.