Characteristics of Ventricular Electrophysiological Substrates in Metabolic Mice Treated with Empagliflozin

Cardiovascular outcomes and molecular targets for the cardiac effects of Sodium-Glucose Cotransporter 2 Inhibitors: A systematic review

Sodium-glucose cotransporter 2 inhibitors (SGLT2i), a new class of glucose-lowering drugs traditionally used to control blood glucose levels in patients with type 2 diabetes mellitus, have been proven to reduce major adverse cardiovascular events, including cardiovascular death, in patients with heart failure irrespective of ejection fraction and independently of the hypoglycemic effect. Because of their favorable effects on the kidney and cardiovascular outcomes, their use has been expanded in all patients with any combination of diabetes mellitus type 2, chronic kidney disease and heart failure. Although mechanisms explaining the effects of these drugs on the cardiovascular system are not well understood, their effectiveness in all these conditions suggests that they act at the intersection of the metabolic, renal and cardiac axes, thus disrupting maladaptive vicious cycles while contrasting direct organ damage. In this systematic review we provide a state of the art of the randomized controlled trials investigating the effect of SGLT2i on cardiovascular outcomes in patients with chronic kidney disease and/or heart failure irrespective of ejection fraction and diabetes. We also discuss the molecular targets and signaling pathways potentially explaining the cardiac effects of these pharmacological agents, from a clinical and experimental perspective.

Sodium-glucose cotransporter type 2 inhibitors and cardiac arrhythmias

The introduction of sodium-glucose cotransporter 2 (SGLT2) inhibitors as a new and effective class of therapeutic agents for type 2 diabetes (T2D) preventing the reabsorption of glucose in the kidneys and thus facilitating glucose excretion in the urine, but also as agents with cardiovascular benefits, particularly in patients with heart failure (HF), regardless of the diabetic status, has ushered in a new era in treating patients with T2D and/or HF. In addition, data have recently emerged indicating an antiarrhythmic effect of the SGLT2 inhibitors in patients with and without diabetes. Prospective studies, randomized controlled trials and meta-analyses have provided robust evidence for a protective and beneficial effect of these agents against atrial fibrillation, ventricular arrhythmias and sudden cardiac death. The antiarrhythmic mechanisms involved include reverse atrial and ventricular remodeling, amelioration of mitochondrial function, reduction of hypoglycemic episodes with their attendant arrhythmogenic effects, attenuated sympathetic nervous system activity, regulation of sodium and calcium homeostasis, and suppression of prolonged ventricular repolarization. These new data on antiarrhythmic actions of SGLT2 inhibitors are herein reviewed, potential mechanisms involved are discussed and pictorially illustrated, and treatment results on specific arrhythmias are described and tabulated.

Impact of Impaired Kidney Function on Arrhythmia-Promoting Cardiac Ion Channel Regulation

Chronic kidney disease (CKD) is associated with a significantly increased risk of cardiovascular events and sudden cardiac death. Although arrhythmias are one of the most common causes of sudden cardiac death in CKD patients, the molecular mechanisms involved in the development of arrhythmias are still poorly understood. In this narrative review, therefore, we summarize the current knowledge on the regulation of cardiac ion channels that contribute to arrhythmia in CKD. We do this by first explaining the excitation-contraction coupling, outlining current translational research approaches, then explaining the main characteristics in CKD patients, such as abnormalities in electrolytes and pH, activation of the autonomic nervous system, and the renin-angiotensin-aldosterone system, as well as current evidence for proarrhythmic properties of uremic toxins. Finally, we discuss the substance class of sodium-glucose co-transporter 2 inhibitors (SGLT2i) on their potential to modify cardiac channel regulation in CKD and, therefore, as a treatment option for arrhythmias.

Editorial to the IJMS Special Issue on Sglt2 Inhibitors Vol. 1

The goal of this Special Issue is to highlight the ever-increasing progress in pharmacological research on sodium-glucose co-transporter (SGLT) type 2 (SGLT2) inhibitors or gliflozins [...].

Sodium Glucose Cotransporter 2 (SGLT2) Inhibitor Ameliorate Metabolic Disorder and Obesity Induced Cardiomyocyte Injury and Mitochondrial Remodeling

Sodium-glucose transporter 2 inhibitors (SGLT2is) exert significant cardiovascular and heart failure benefits in type 2 diabetes mellitus (DM) patients and can help reduce cardiac arrhythmia incidence in clinical practice. However, its effect on regulating cardiomyocyte mitochondria remain unclear. To evaluate its effect on myocardial mitochondria, C57BL/6J mice were divided into four groups, including: (1) control, (2) high fat diet (HFD)-induced metabolic disorder and obesity (MDO), (3) MDO with empagliflozin (EMPA) treatment, and (4) MDO with glibenclamide (GLI) treatment. All mice were sacrificed after 16 weeks of feeding and the epicardial fat secretome was collected. H9c2 cells were treated with the different secretomes for 18 h. ROS production, Ca2+ distribution, and associated proteins expression in mitochondria were investigated to reveal the underlying mechanisms of SGLT2is on cardiomyocytes. We found that lipotoxicity, mitochondrial ROS production, mitochondrial Ca2+ overload, and the levels of the associated protein, SOD1, were significantly lower in the EMPA group than in the MDO group, accompanied with increased ATP production in the EMPA-treated group. The expression of mfn2, SIRT1, and SERCA were also found to be lower after EMPA-secretome treatment. EMPA-induced epicardial fat secretome in mice preserved a better cardiomyocyte mitochondrial biogenesis function than the MDO group. In addition to reducing ROS production in mitochondria, it also ameliorated mitochondrial Ca2+ overload caused by MDO-secretome. These findings provide evidence and potential mechanisms for the benefit of SGLT2i in heart failure and arrhythmias.

Changes in Proximal Tubular Reabsorption Modulate Microvascular Regulation via the TGF System

This review paper considers the consequences of modulating tubular reabsorption proximal to the macula densa by sodium–glucose co-transporter 2 (SGLT2) inhibitors, acetazolamide, and furosemide in states of glomerular hyperfiltration. SGLT2 inhibitors improve renal function in early and advanced diabetic nephropathy by decreasing the glomerular filtration rate (GFR), presumably by activating the tubuloglomerular feedback (TGF) mechanism. Central in this paper is that the renoprotective effects of SGLT2 inhibitors in diabetic nephropathy can only be partially explained by TGF activation, and there are alternative explanations. The sustained activation of TGF leans on two prerequisites: no or only partial adaptation should occur in reabsorption proximal to macula densa, and no or only partial adaptation should occur in the TGF response. The main proximal tubular and loop of Henle sodium transporters are sodium–hydrogen exchanger 3 (NHE3), SGLT2, and the Na-K-2Cl co-transporter (NKCC2). SGLT2 inhibitors, acetazolamide, and furosemide are the most important compounds; inhibiting these transporters would decrease sodium reabsorption upstream of the macula densa and increase TGF activity. This could directly or indirectly affect TGF responsiveness, which could oppose sustained TGF activation. Only SGLT2 inhibitors can sustainably activate the TGF as there is only partial compensation in tubular reabsorption and TGF response. SGLT2 inhibitors have been shown to preserve GFR in both early and advanced diabetic nephropathy. Other than for early diabetic nephropathy, a solid physiological basis for these effects in advanced nephropathy is lacking. In addition, TGF has hardly been studied in humans, and therefore this role of TGF remains elusive. This review also considers alternative explanations for the renoprotective effects of SGLT2 inhibitors in diabetic patients such as the enhancement of microvascular network function. Furthermore, combination use of SGLT2 inhibitors and angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARBs). in diabetes can decrease inflammatory pathways, improve renal oxygenation, and delay the progression of diabetic nephropathy.

SGLT2 inhibitors improve kidney function and morphology by regulating renal metabolic reprogramming in mice with diabetic kidney disease

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD) worldwide. SGLT2 inhibitors are clinically effective in halting DKD progression. However, the underlying mechanisms remain unclear. The serum and kidneys of mice with DKD were analyzed using liquid chromatography with tandem mass spectrometry (LC–MS/MS)-based metabolomic and proteomic analyses. Three groups were established: placebo-treated littermate db/m mice, placebo-treated db/db mice and EMPA-treated db/db mice. Empagliflozin (EMPA) and placebo (10 mg/kg/d) were administered for 12 weeks. EMPA treatment decreased Cys-C and urinary albumin excretion compared with placebo by 78.60% and 57.12%, respectively (p < 0.001 in all cases). Renal glomerular area, interstitial fibrosis and glomerulosclerosis were decreased by 16.47%, 68.50% and 62.82%, respectively (p < 0.05 in all cases). Multi-omic analysis revealed that EMPA treatment altered the protein and metabolic profiles in the db/db group, including 32 renal proteins, 51 serum proteins, 94 renal metabolites and 37 serum metabolites. Five EMPA-related metabolic pathways were identified by integrating proteomic and metabolomic analyses, which are involved in renal purine metabolism; pyrimidine metabolism; tryptophan metabolism; nicotinate and nicotinamide metabolism, and glycine, serine and threonine metabolism in serum. In conclusion, this study demonstrated metabolic reprogramming in mice with DKD. EMPA treatment improved kidney function and morphology by regulating metabolic reprogramming, including regulation of renal reductive stress, alleviation of mitochondrial dysfunction and reduction in renal oxidative stress reaction.

Association between Empagliflozin Use and Electrocardiographic Changes

Empagliflozin, a sodium-glucose transporter 2 inhibitor, has been shown to bind to late sodium channels in mice cardiomyocytes. We sought to investigate the electrocardiographic (ECG) features associated with empagliflozin use in patients with diabetes mellitus. We compared ECG features of 101 patients before and after initiation of empagliflozin and found that empagliflozin was associated with a significant increase in QRS duration among diabetes patients with heart failure.

Anti-Arrhythmic Effects of Sodium-Glucose Co-Transporter 2 Inhibitors

Arrhythmias are clinically prevalent with a high mortality rate. They impose a huge economic burden, thereby substantially affecting the quality of life. Sodium-glucose co-transporter 2 inhibitor (SGLT2i) is a new type of hypoglycemic drug, which can regulate blood glucose level safely and effectively. Additionally, it reduces the occurrence and progression of heart failure and cardiovascular events significantly. Recently, studies have found that SGLT2i can alleviate the occurrence and progression of cardiac arrhythmias; however, the exact mechanism remains unclear. In this review, we aimed to discuss and summarize new literature on different modes in which SGLT2i ameliorates the occurrence and development of cardiac arrhythmias.

Potential roles of sodium-glucose co-transporter 2 inhibitors in attenuating cardiac arrhythmias in diabetes and heart failure

Sodium-glucose co-transporter 2 (SGLT-2) inhibitors are antidiabetic drugs that have been shown to exert cardiovascular benefits. Their benefits including a reduction of cardiovascular events and worsening heart failure have been extended to nondiabetic patients with high-risk. Although both heart failure and diabetes are known to increase risk of cardiac arrhythmias, the effects of SGLT-2 inhibitors on arrhythmia reduction and their underlying mechanisms are still not fully understood. This review aims to summarize the current available evidence ranging from basic research to clinical reports regarding the potential benefits of SGLT-2 inhibitors against cardiac arrhythmias. Previous in vitro and in vivo studies using various models including heart failure and diabetes are comprehensively summarized to examine the evidence of how SGLT-2 inhibitors affect cardiac action potential, cellular ion currents, calcium ion homeostasis, and cardiac mitochondrial function. Clinical reports investigating the association between SGLT-2 inhibitors and arrhythmias including atrial fibrillation and ventricular arrhythmias are also comprehensively summarized. Valuable information obtained from this review can be used to encourage further clinical investigations to warrant the potential use of SGLT-2 inhibitors against cardiac arrhythmias in both diabetic and heart failure settings.

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

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

Mechanisms Underlying Antiarrhythmic Properties of Cardioprotective Agents Impacting Inflammation and Oxidative Stress

The prevention of cardiac life-threatening ventricular fibrillation and stroke-provoking atrial fibrillation remains a serious global clinical issue, with ongoing need for novel approaches. Numerous experimental and clinical studies suggest that oxidative stress and inflammation are deleterious to cardiovascular health, and can increase heart susceptibility to arrhythmias. It is quite interesting, however, that various cardio-protective compounds with antiarrhythmic properties are potent anti-oxidative and anti-inflammatory agents. These most likely target the pro-arrhythmia primary mechanisms. This review and literature-based analysis presents a realistic view of antiarrhythmic efficacy and the molecular mechanisms of current pharmaceuticals in clinical use. These include the sodium-glucose cotransporter-2 inhibitors used in diabetes treatment, statins in dyslipidemia and naturally protective omega-3 fatty acids. This approach supports the hypothesis that prevention or attenuation of oxidative and inflammatory stress can abolish pro-arrhythmic factors and the development of an arrhythmia substrate. This could prove a powerful tool of reducing cardiac arrhythmia burden.

Effects of sodium-glucose cotransporter-2 inhibitors on cardiac structural and electrical remodeling: from myocardial cytology to cardiodiabetology

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have changed the clinical landscape of diabetes mellitus (DM) therapy through their favourable effects on cardiovascular outcomes. Notably, the use of SGLT2i has been linked to cardiovascular benefits regardless of DM status, while their pleiotropic actions remain to be fully elucidated. What we do know is that SGLT2i exert beneficial effects even at the level of the myocardial cell, and that these are linked to an improvement in the energy substrate, resulting in less inflammation and fibrosis. SGLT2i ameliorate myocardial extracellular matrix remodeling, cardiomyocyte stiffness and concentric hypertrophy, achieving beneficial remodeling of the left ventricle with significant implications for the pathogenesis and outcome of heart failure. Most studies show a significant improvement in markers of diastolic dysfunction along with a reduction in left ventricular hypertrophy. In addition to these effects there is electrophysiological remodeling, which explains initial data suggesting that SGLT2i have an antiarrhythmic action against both atrial and ventricular arrhythmias. However, future studies need to clarify not only the exact mechanisms of this beneficial functional, structural, and electrophysiological cardiac remodeling, but also its magnitude, and to determine whether this is a class or a drug effect.