Therapeutic Manipulation of Myocardial Metabolism: JACC State-of-the-Art Review

The Off-Target Cardioprotective Mechanisms of Sodium-Glucose Cotransporter 2 Inhibitors: An Overview

Sodium-glucose cotransporter 2 inhibitors (SGLT2i), a novel class of glucose-lowering drugs, have revolutionized the management of heart failure with reduced and preserved ejection fraction, regardless of the presence of diabetes, and are currently incorporated in the heart failure guidelines. While these drugs have consistently demonstrated their ability to decrease heart failure hospitalizations in several landmark clinical trials, their cardioprotective effects are far from having been completely elucidated. In the past decade, a growing body of experimental research has sought to address the molecular and cellular mechanisms of SGLT2i in order to provide a better understanding of the off-target acute and chronic cardiac benefits, beyond the on-target renal effect responsible for blood glucose reduction. The present narrative review addresses the direct cardioprotective effects of SGLT2i, delving into the off-target mechanisms of the drugs currently approved for heart failure therapy, and provides insights into future perspectives.

Therapeutic potential of the ketogenic diet: A metabolic switch with implications for neurological disorders, the gut-brain axis, and cardiovascular diseases

The Ketogenic Diet (KD) is a dietary regimen that is low in carbohydrates, high in fats, and contains adequate protein. It is designed to mimic the metabolic state of fasting. This diet triggers the production of ketone bodies through a process known as ketosis. The primary objective of KD is to induce and sustain ketosis, which has been associated with numerous health benefits. Recent research has uncovered promising therapeutic potential for KD in the treatment of various diseases. This includes evidence of its effectiveness as a dietary strategy for managing intractable epilepsy, a form of epilepsy that is resistant to medication. We are currently assessing the efficacy and safety of KD through laboratory and clinical studies. This review focuses on the anti-inflammatory properties of the KD and its potential benefits for neurological disorders and the gut-brain axis. We also explore the existing literature on the potential effects of KD on cardiac health. Our aim is to provide a comprehensive overview of the current knowledge in these areas. Given the encouraging preliminary evidence of its therapeutic effects and the growing understanding of its mechanisms of action, randomized controlled trials are warranted to further explore the rationale behind the clinical use of KD. These trials will ultimately enhance our understanding of how KD functions and its potential benefits for various health conditions. We hope that our research will contribute to the body of knowledge in this field and provide valuable insights for future studies.

Liraglutide Pretreatment Does Not Improve Acute Doxorubicin-Induced Cardiotoxicity in Rats

Doxorubicin is an effective drug for cancer treatment; however, cardiotoxicity limits its use. Cardiotoxicity pathophysiology is multifactorial. GLP-1 analogues have been shown to reduce oxidative stress and inflammation. In this study, we evaluated the effect of pretreatment with liraglutide on doxorubicin-induced acute cardiotoxicity. A total of 60 male Wistar rats were allocated into four groups: Control (C), Doxorubicin (D), Liraglutide (L), and Doxorubicin + Liraglutide (DL). L and DL received subcutaneous injection of liraglutide 0.6 mg/kg daily, while C and D received saline for 2 weeks. Afterwards, D and DL received a single intraperitoneal injection of doxorubicin 20 mg/kg; C and L received an injection of saline. Forty-eight hours after doxorubicin administration, the rats were subjected to echocardiogram, isolated heart functional study, and euthanasia. Liraglutide-treated rats ingested significantly less food and gained less body weight than animals that did not receive the drug. Rats lost weight after doxorubicin injection. At echocardiogram and isolated heart study, doxorubicin-treated rats had systolic and diastolic function impairment. Myocardial catalase activity was statistically higher in doxorubicin-treated rats. Myocardial protein expression of tumor necrosis factor alpha (TNF-α), phosphorylated nuclear factor-κB (p-NFκB), troponin T, and B-cell lymphoma 2 (Bcl-2) was significantly lower, and the total NFκB/p-NFκB ratio and TLR-4 higher in doxorubicin-treated rats. Myocardial expression of OPA-1, MFN-2, DRP-1, and topoisomerase 2β did not differ between groups (p > 0.05). In conclusion, doxorubicin-induced cardiotoxicity is accompanied by decreased Bcl-2 and phosphorylated NFκB and increased catalase activity and TLR-4 expression. Liraglutide failed to improve acute doxorubicin-induced cardiotoxicity in rats.

Recent advances in mechanistic studies of heart failure with preserved ejection fraction and its comorbidities-Role of microRNAs

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome with a complex aetiology commonly associated with comorbidities such as diabetes mellitus, obesity, hypertension and renal disease. Various diseases induce systemic, chronic and low-grade inflammation; microvascular dysfunction; metabolic stress; tissue ischemia; and fibrosis, leading to HFpEF. An effective treatment for HFpEF is lacking, largely owing to its pathophysiological heterogeneity. Recent studies have revealed that microRNAs (miRNAs) play crucial roles in regulating the pathogenesis of HFpEF and its comorbidities.

METHODS

This narrative review included original articles and reviews published over the past 20 years found through 'PubMed' and 'Web of Science'. The search terms included "HFpEF," "MicroRNAs," "comorbidities," "Microvascular Dysfunction (MVD)," "inflammation," "pathophysiology," "endothelial dysfunction," "energy metabolism abnormalities" "cardiac fibrosis" and "treatment."

RESULTS

Inflammation, MVD, abnormal energy metabolism, myocardial hypertrophy and myocardial fibrosis are important pathophysiological mechanisms underlying HFpEF. As gene expression regulators, miRNAs may contribute to the pathophysiology of HFpEF and are expected to serve in the stratification of patients with HFpEF and as prognostic indicators for monitoring treatment responses.

CONCLUSIONS

A customized strategy based on miRNAs has emerged as an effective treatment for HFpEF. In this review, we discuss recent research surrounding miRNAs and HFpEF and propose potential miRNA targets for the pathophysiology of HFpEF and its comorbidities. Although current research concerning miRNAs and their therapeutic potential is in its early stages, miRNA-based diagnostics and therapeutics hold great promise in the future.

The effect of time of eating on cardiometabolic risk in primary and secondary prevention of cardiovascular disease

Continuous energy restriction is currently considered the first-line dietary therapy for weight loss in individuals with obesity. Recently, interventions which alter the eating window and time of eating occasions have been explored as means to achieve weight loss and other cardiometabolic improvements such as a reduction in blood pressure, glycaemia, lipids and inflammation. It is unknown, however, whether these changes result from unintentional energy restriction or from other mechanisms such as the alignment of nutrient intake with the internal circadian clock. Even less is known regarding the safety and efficacy of these interventions in individuals with established chronic noncommunicable disease states, such as cardiovascular disease. This review examines the effects of interventions which alter both eating window and time of eating occasions on weight and other cardiometabolic risk factors in both healthy participants and those with established cardiovascular disease. We then summarise the state of existing knowledge and explore future directions of study.

Time of eating and mortality in U.S. adults with heart failure: Analyses of the National Health and Nutrition Examination Survey 2003-2018

BACKGROUND AND AIMS

Promising associations have been demonstrated between delayed last eating occasion and cardiorespiratory fitness in adults with heart failure (HF), however, it is unknown if time of eating is associated with clinical endpoints such as mortality. This study aimed to examine associations between time of eating variables and all-cause and cardiovascular mortality in the National Health and Nutrition Examination Survey (NHANES).

METHODS AND RESULTS

Participants self-disclosed HF diagnosis. Two dietary recalls were obtained and categorical variables were created based on mean time of first eating occasion (8:31 AM), last eating occasion (7:33 PM) and eating window (11.02 h). Mortality was obtained through linkage to the National Death Index. Covariate-adjusted Cox proportional hazard regression models were created examining the association between time of eating and mortality. Participants (n = 991) were 68 (95 % CI 67-69) years of age, 52.6 (95 % CI 49.0-56.3)% men and had a body mass index of 32.5 (95 % CI 31.8-33.2) kg/m2 with follow up time of 68.9 (95 % CI 64.8-72.9) person-months. When models were adjusted for time of eating variables and all other covariates, extending the eating window beyond 11.02 h was associated with decreased risk of cardiovascular (HR 0.36 [95 % CI 0.16-0.81]), but not all-cause mortality. Time of first and last eating occasions were not associated with mortality.

CONCLUSIONS

In adults with HF, an extended eating window is associated with reduced risk for cardiovascular mortality. Randomized controlled trials should examine if extending the eating window can improve prognostic indicators such as cardiorespiratory fitness in this population.

Enhancing myocardial function with cardiac contractility modulation: potential and challenges

Cardiac contractility modulation (CCM) offers a novel therapeutic avenue for heart failure patients, particularly those unresponsive to cardiac resynchronization therapy within specific QRS duration ranges. This review elucidates CCM's mechanistic underpinnings, its impact on myocardial function, and utility across patient demographics. However, CCM is limited by insufficient data on mortality and hospitalization rate reductions, as well as the need for specialized device implantation skills. While prevailing research has concentrated on left ventricular effects, a knowledge gap persists for other patient subsets. Future inquiries should address combinatory treatment strategies, extended usage and the impact of atrial fibrillation on device implantation. Such expanded studies could refine therapeutic outcomes and widen the scope of beneficiaries.

High serum lactate dehydrogenase as a predictor of cardiac insufficiency at follow-up in elderly patients with acute myocardial infarction

BACKGROUND

Impairment of cardiac function progresses after acute myocardial infarction (AMI). Lactate dehydrogenase (LDH), a marker of cardiac injury and an enzyme in anaerobic glycolysis, is suggested as a risk factor for patient mortality in inflammatory diseases.

METHODS

In this study, 448 older and 445 younger AMI patients were recruited and followed up. The effect of baseline serum LDH on post-infarction cardiac function was assessed at follow-up.

RESULTS

Elderly patients in the high baseline LDH group had a high risk of being diagnosed with cardiac insufficiency during follow-up (adjusted hazard ratio: 3.643, P = 0.007), and the follow-up left ventricular ejection fraction of the quartile subgroup tended to decrease with increasing in baseline serum LDH (adjusted odds ratio: 1.301, P = 0.001) for each 100 U/L increase. The LVDd and LVVd of elderly patients in the high LDH group were not significantly different from those of patients in the normal LDH group at baseline but were further increased in the high LDH group at follow-up. In younger patients, the effect of LDH on post-infarction cardiac structure and function was similar to that in older patients, but unlike older patients, Cox regression analysis showed that LDH was not the predominant influence.

CONCLUSION

Longitudinal changes in cardiac function were independently associated with high baseline serum LDH levels in patients with AMI. Baseline LDH levels are superior to other myocardial injury markers and may be a useful parameter in predicting future cardiac dysfunction after AMI, especially in the elderly.

From Energy Metabolic Change to Precision Therapy: a Holistic View of Energy Metabolism in Heart Failure

Heart failure (HF) is a complex and multifactorial disease that affects millions of people worldwide. It is characterized by metabolic disturbances of substrates such as glucose, fatty acids (FAs), ketone bodies, and amino acids, which lead to changes in cardiac energy metabolism pathways. These metabolic alterations can directly or indirectly promote myocardial remodeling, thereby accelerating the progression of HF, resulting in a vicious cycle of worsening symptoms, and contributing to the increased hospitalization and mortality among patients with HF. In this review, we summarized the latest researches on energy metabolic profiling in HF and provided the related translational therapeutic strategies for this devastating disease. By taking a holistic approach to understanding energy metabolism changes in HF, we hope to provide comprehensive insights into the pathophysiology of this challenging condition and identify novel precise targets for the development of more effective treatments.

Biochemical Aspects That Lead to Abusive Use of Trimetazidine in Performance Athletes: A Mini-Review

Trimetazidine (TMZ), used for treating stable angina pectoris, has garnered attention in the realm of sports due to its potential performance-enhancing properties, and the World Anti-Doping Agency (WADA) has classified TMZ on the S4 list of prohibited substances since 2014. The purpose of this narrative mini-review is to emphasize the biochemical aspects underlying the abusive use of TMZ among athletes as a metabolic modulator of cardiac energy metabolism. The myocardium's ability to adapt its energy substrate utilization between glucose and fatty acids is crucial for maintaining cardiac function under various conditions, such as rest, moderate exercise, and intense effort. TMZ acts as a partial inhibitor of fatty acid oxidation by inhibiting 3-ketoacyl-CoA thiolase (KAT), shifting energy production from long-chain fatty acids to glucose, reducing oxygen consumption, improving cardiac function, and enhancing exercise capacity. Furthermore, TMZ modulates pyruvate dehydrogenase (PDH) activity, promoting glucose oxidation while lowering lactate production, and ultimately stabilizing myocardial function. TMZs role in reducing oxidative stress is notable, as it activates antioxidant enzymes like glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). In conclusion, TMZs biochemical mechanisms make it an attractive but controversial option for athletes seeking a competitive edge.

α-Ketoglutarate improves cardiac insufficiency through NAD+-SIRT1 signaling-mediated mitophagy and ferroptosis in pressure overload-induced mice

BACKGROUND

In heart failure (HF), mitochondrial dysfunction and metabolic remodeling lead to a reduction in energy productivity and aggravate cardiomyocyte injury. Supplementation with α-ketoglutarate (AKG) alleviated myocardial hypertrophy and fibrosis in mice with HF and improved cardiac insufficiency. However, the myocardial protective mechanism of AKG remains unclear. We verified the hypothesis that AKG improves mitochondrial function by upregulating NAD+ levels and activating silent information regulator 2 homolog 1 (SIRT1) in cardiomyocytes.

METHODS

In vivo, 2% AKG was added to the drinking water of mice undergoing transverse aortic constriction (TAC) surgery. Echocardiography and biopsy were performed to evaluate cardiac function and pathological changes. Myocardial metabolomics was analyzed by liquid chromatography‒mass spectrometry (LC‒MS/MS) at 8 weeks after surgery. In vitro, the expression of SIRT1 or PINK1 proteins was inhibited by selective inhibitors and siRNA in cardiomyocytes stimulated with angiotensin II (AngII) and AKG. NAD+ levels were detected using an NAD test kit. Mitophagy and ferroptosis levels were evaluated by Western blotting, qPCR, JC-1 staining and lipid peroxidation analysis.

RESULTS

AKG supplementation after TAC surgery could alleviate myocardial hypertrophy and fibrosis and improve cardiac function in mice. Metabolites of the malate-aspartate shuttle (MAS) were increased, but the TCA cycle and fatty acid metabolism pathway could be inhibited in the myocardium of TAC mice after AKG supplementation. Decreased NAD+ levels and SIRT1 protein expression were observed in heart of mice and AngII-treated cardiomyocytes. After AKG treatment, these changes were reversed, and increased mitophagy, inhibited ferroptosis, and alleviated damage in cardiomyocytes were observed. When the expression of SIRT1 was inhibited by a selective inhibitor and siRNA, the protective effect of AKG was suppressed.

CONCLUSION

Supplementation with AKG can improve myocardial hypertrophy, fibrosis and chronic cardiac insufficiency caused by pressure overload. By increasing the level of NAD+, the SIRT-PINK1 and SIRT1-GPX4 signaling pathways are activated to promote mitophagy and inhibit ferroptosis in cardiomyocytes, which ultimately alleviates cardiomyocyte damage.

The Ketogenic Effect of SGLT-2 Inhibitors-Beneficial or Harmful?

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors, also called gliflozins or flozins, are a class of drugs that have been increasingly used in the management of type 2 diabetes mellitus (T2DM) due to their glucose-lowering, cardiovascular (CV), and renal positive effects. However, recent studies suggest that SGLT-2 inhibitors might also have a ketogenic effect, increasing ketone body production. While this can be beneficial for some patients, it may also result in several potential unfavorable effects, such as decreased bone mineral density, infections, and ketoacidosis, among others. Due to the intricate and multifaceted impact caused by SGLT-2 inhibitors, this initially anti-diabetic class of medications has been effectively used to treat both patients with chronic kidney disease (CKD) and those with heart failure (HF). Additionally, their therapeutic potential appears to extend beyond the currently investigated conditions. The objective of this review article is to present a thorough summary of the latest research on the mechanism of action of SGLT-2 inhibitors, their ketogenesis, and their potential synergy with the ketogenic diet for managing diabetes. The article particularly discusses the benefits and risks of combining SGLT-2 inhibitors with the ketogenic diet and their clinical applications and compares them with other anti-diabetic agents in terms of ketogenic effects. It also explores future directions regarding the ketogenic effects of SGLT-2 inhibitors.

The role of mitochondria in myocardial damage caused by energy metabolism disorders: From mechanisms to therapeutics

Myocardial damage is the most serious pathological consequence of cardiovascular diseases and an important reason for their high mortality. In recent years, because of the high prevalence of systemic energy metabolism disorders (e.g., obesity, diabetes mellitus, and metabolic syndrome), complications of myocardial damage caused by these disorders have attracted widespread attention. Energy metabolism disorders are independent of traditional injury-related risk factors, such as ischemia, hypoxia, trauma, and infection. An imbalance of myocardial metabolic flexibility and myocardial energy depletion are usually the initial changes of myocardial injury caused by energy metabolism disorders, and abnormal morphology and functional destruction of the mitochondria are their important features. Specifically, mitochondria are the centers of energy metabolism, and recent evidence has shown that decreased mitochondrial function, caused by an imbalance in mitochondrial quality control, may play a key role in myocardial injury caused by energy metabolism disorders. Under chronic energy stress, mitochondria undergo pathological fission, while mitophagy, mitochondrial fusion, and biogenesis are inhibited, and mitochondrial protein balance and transfer are disturbed, resulting in the accumulation of nonfunctional and damaged mitochondria. Consequently, damaged mitochondria lead to myocardial energy depletion and the accumulation of large amounts of reactive oxygen species, further aggravating the imbalance in mitochondrial quality control and forming a vicious cycle. In addition, impaired mitochondria coordinate calcium homeostasis imbalance, and epigenetic alterations participate in the pathogenesis of myocardial damage. These pathological changes induce rapid progression of myocardial damage, eventually leading to heart failure or sudden cardiac death. To intervene more specifically in the myocardial damage caused by metabolic disorders, we need to understand the specific role of mitochondria in this context in detail. Accordingly, promising therapeutic strategies have been proposed. We also summarize the existing therapeutic strategies to provide a reference for clinical treatment and developing new therapies.

Cardiometabolic risk management: insights from a European Society of Cardiology Cardiovascular Round Table

Metabolic comorbidities are common in patients with cardiorenal disease; they can cause atherosclerotic cardiovascular disease (ASCVD), speed progression, and adversely affect prognosis. Common comorbidities are Type 2 diabetes mellitus (T2DM), obesity/overweight, chronic kidney disease (CKD), and chronic liver disease. The cardiovascular system, kidneys, and liver are linked to many of the same risk factors (e.g. dyslipidaemia, hypertension, tobacco use, diabetes, and central/truncal obesity), and shared metabolic and functional abnormalities lead to damage throughout these organs via overlapping pathophysiological pathways. The COVID-19 pandemic has further complicated the management of cardiometabolic diseases. Obesity, T2DM, CKD, and liver disease are associated with increased risk of poor outcomes of COVID-19 infection, and conversely, COVID-19 can lead to worsening of pre-existing ASCVD. The high rates of these comorbidities highlight the need to improve recognition and treatment of ASCVD in patients with obesity, insulin resistance or T2DM, chronic liver diseases, and CKD and equally, to improve recognition and treatment of these diseases in patients with ASCVD. Strategies to prevent and manage cardiometabolic diseases include lifestyle modification, pharmacotherapy, and surgery. There is a need for more programmes at the societal level to encourage a healthy diet and physical activity. Many pharmacotherapies offer mechanism-based approaches that can target multiple pathophysiological pathways across diseases. These include sodium-glucose cotransporter-2 inhibitors, glucagon-like peptide-1 receptor agonists, selective mineralocorticoid receptor antagonists, and combined glucose-dependent insulinotropic peptide/glucagon-like peptide-1 receptor agonist. Non-surgical and surgical weight loss strategies can improve cardiometabolic disorders in individuals living with obesity. New biomarkers under investigation may help in the early identification of individuals at risk and reveal new treatment targets.

Case report: Sodium-glucose cotransporter 2 inhibitors induce left ventricular reverse remodeling in anthracycline-related cardiac dysfunction-a case series

Purpose

To describe the efficacy and safety of sodium-glucose cotransporter 2 inhibitors as a specific treatment for anthracycline-related cardiac dysfunction in a small real-world population.

Methods

Seven patients with anthracycline-related cardiac dysfunction were clinically and echocardiographically evaluated before and after the introduction of sodium-glucose cotransporter 2 inhibitors.

Results

After a median period of 24 weeks with uninterrupted sodium-glucose cotransporter 2 inhibitors treatment, a significant clinical improvement was observed with at least one New York Heart Association Functional Class (NHYA FC) improvement in all patients (median NYHA FC: I vs. III, p < 0.010). A noteworthy left ventricular reserve remodeling (median left ventricular end diastolic volume indexed: 53 vs. 82.5 ml/m2, p = 0.018; median left ventricular ejection fraction: 50% vs. 40%, p = 0.17) was also observed. Sodium-glucose cotransporter 2 inhibitors therapy was well tolerated by every patients; no cases of discontinuation or relevant side effects were observed.

Conclusion

Sodium-glucose cotransporter 2 inhibitors induce a significant clinical improvement and left ventricular reserve remodeling in patients affected by anthracycline-related cardiac dysfunction.

Impact of Geroscience on Therapeutic Strategies for Older Adults With Cardiovascular Disease: JACC Scientific Statement

Geroscience posits that cardiovascular disease (CVD) and other chronic diseases result from progressive erosion of the effectiveness of homeostatic mechanisms that oppose age-related accumulation of molecular damage. This hypothetical common root to chronic diseases explains why patients with CVD are often affected by multimorbidity and frailty and why older age negatively affects CVD prognosis and treatment response. Gerotherapeutics enhance resilience mechanisms that counter age-related molecular damage to prevent chronic diseases, frailty, and disability, thereby extending healthspan. Here, we describe the main resilience mechanisms of mammalian aging, with a focus on how they can affect CVD pathophysiology. We next present novel gerotherapeutic approaches, some of which are already used in management of CVD, and explore their potential to transform care and management of CVD. The geroscience paradigm is gaining traction broadly in medical specialties, with potential to mitigate premature aging, reduce health care disparities, and improve population healthspan.

Empagliflozin improves insulin sensitivity in patients with recent acute coronary syndrome and newly detected dysglycaemia : Experiences from the randomized, controlled SOCOGAMI trial

BACKGROUND

Empagliflozin reduces the risk of cardiovascular disease (CVD) in patients with type 2 diabetes (T2DM) and high cardiovascular risk via mechanisms which have not been fully explained. The mechanisms of such benefit have not been fully understood, and whether empagliflozin can be safely administered as first-line treatment in patients with CVD at the initial stages of glycaemic perturbations remains to be established. We investigated the effects of empagliflozin on insulin resistance, insulin sensitivity and β-cell function indexes in patients with a recent acute coronary event and newly detected dysglycaemia, i.e., impaired glucose tolerance (IGT) or T2DM.

METHODS

Forty-two patients (mean age 67.5 years, 19% females) with a recent myocardial infarction (n = 36) or unstable angina (n = 6) and newly detected dysglycaemia were randomized to either empagliflozin 25 mg daily (n = 20) or placebo (n = 22). Patients were investigated with stress-perfusion cardiac magnetic resonance imaging before randomization, 7 months after the start of study drug and 3 months following its cessation. Indexes of insulin resistance, sensitivity and β-cell function were calculated based on glucose and insulin values from 2-hour oral glucose tolerance tests (OGTT) and fasting C-peptide. The differences in glucose, insulin, C-peptide, mannose levels and indexes between the two groups were computed by repeated measures ANOVA including an interaction term between the treatment allocation and the time of visit.

RESULTS

After 7 months, empagliflozin significantly decreased glucose and insulin values during the OGTT, whereas C-peptide, mannose and HbA1c did not differ. Empagliflozin significantly improved insulin sensitivity indexes but did not impact insulin resistance and β-cell function. After cessation of the drug, all indexes returned to initial levels. Insulin sensitivity indexes were inversely correlated with left ventricular mass at baseline.

CONCLUSIONS

Empagliflozin improved insulin sensitivity indexes in patients with a recent coronary event and drug naïve dysglycaemia. These findings support the safe use of empagliflozin as first-line glucose-lowering treatment in patients at very high cardiovascular risk with newly diagnosed dysglycaemia.

TRIAL REGISTRATION NUMBER

EudraCT number 2015-004571-73.

The Impact of Pharmacotherapy for Heart Failure on Oxidative Stress-Role of New Drugs, Flozins

Heart failure (HF) is a multifactorial clinical syndrome involving many complex processes. The causes may be related to abnormal heart structure and/or function. Changes in the renin-angiotensin-aldosterone system, the sympathetic nervous system, and the natriuretic peptide system are important in the pathophysiology of HF. Dysregulation or overexpression of these processes leads to changes in cardiac preload and afterload, changes in the vascular system, peripheral vascular dysfunction and remodeling, and endothelial dysfunction. One of the important factors responsible for the development of heart failure at the cellular level is oxidative stress. This condition leads to deleterious cellular effects as increased levels of free radicals gradually disrupt the state of equilibrium, and, as a consequence, the internal antioxidant defense system is damaged. This review focuses on pharmacotherapy for chronic heart failure with regard to oxidation-reduction metabolism, with special attention paid to the latest group of drugs, SGLT2 inhibitors-an integral part of HF treatment. These drugs have been shown to have beneficial effects by protecting the antioxidant system at the cellular level.

Mechanistic insights of soluble uric acid-induced insulin resistance: Insulin signaling and beyond

Hyperuricemia is a metabolic disease caused by purine nucleotide metabolism disorder. The prevalence of hyperuricemia is increasing worldwide, with a growing trend in the younger populations. Although numerous studies have indicated that hyperuricemia may be an independent risk factor for insulin resistance, the causal relationship between the two is controversial. There are few reviews, however, focusing on the relationship between uric acid (UA) and insulin resistance from experimental studies. In this review, we summarized the experimental models related to soluble UA-induced insulin resistance in pancreas and peripheral tissues, including skeletal muscles, adipose tissue, liver, heart/cardiomyocytes, vascular endothelial cells and macrophages. In addition, we summarized the research advances about the key mechanism of UA-induced insulin resistance. Moreover, we attempt to identify novel targets for the treatment of hyperuricemia-related insulin resistance. Lastly, we hope that the present review will encourage further researches to solve the chicken-and-egg dilemma between UA and insulin resistance, and provide strategies for the pathogenesis and treatment of hyperuricemia related metabolic diseases.

The Lure of Cardiac Metabolism in the Diagnosis, Prevention, and Treatment of Heart Failure

Energy substrate metabolism and contractile function are tightly coupled in the heart. Within this framework, heart failure may be viewed as a state of impaired energy transfer. The metabolic changes in the failing heart are linked to functional and structural changes. A worthwhile goal is to measure metabolic flux and its regulation quantitatively, and to do this in a manner that leads to targeted interventions. For several good reasons, this goal has been elusive until now. The development of new analytical and imaging techniques offers the potential of exploring the landscape of metabolic changes across the different stages of heart failure. In this Review Topic of the Month, we focus on concepts and brevity to provide a strategic overview of cardiac metabolism in the diagnosis, prevention, and treatment of nonischemic heart failure.

Predictive value of remnant cholesterol level for all-cause mortality in heart failure patients

Background

Lower cholesterol levels are associated with increased mortality in heart failure (HF) patients. Remnant cholesterol corresponds to all cholesterol not found in high-density lipoprotein (HDL) and low-density lipoprotein (LDL). The prognostic role of remnant cholesterol in HF remains unknown.

Objective

To reveal the relationship between the baseline remnant cholesterol level and all-cause mortality in HF patients.

Methods

This study enrolled 2,823 patients hospitalized for HF. Kaplan-Meier analysis, Cox regression, C-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to evaluate the prognostic value of remnant cholesterol for all-cause mortality in HF.

Results

The mortality rate was lowest in the fourth quartile of remnant cholesterol, which had an adjusted hazard ratio (HR) for death of 0.56 [HR: 0.39, 95% confidence interval (CI): 0.46-0.68, p < 0.001] relative to the first quartile. After adjustment, a one-unit increase in the level of remnant cholesterol was associated with a 41% decrease in the risk of all-cause mortality (HR: 0.59, 95% CI: 0.47-0.73, p < 0.001). A refinement in risk prediction was observed after adding remnant cholesterol quartile to the original model (ΔC-statistic = 0.010, 95% CI: 0.003-0.017; NRI = 0.036, 95% CI: 0.003-0.070; IDI = 0.025, 95% CI: 0.018-0.033; all p < 0.05).

Conclusion

Low remnant cholesterol levels are associated with increased all-cause mortality in HF patients. The addition of the remnant cholesterol quartile improved the predictive value over traditional risk factors.

Clinical Trial Registration

ClinicalTrials.gov, Unique Identifier: NCT02664818.

Effects of 26 weeks of treatment with empagliflozin versus glimepiride on the myocardial glucose metabolic rate in patients with type 2 diabetes: The randomized, open-label, crossover, active-comparator FIORE trial

AIM

To determine whether treatment with empagliflozin was able to affect the myocardial glucose metabolic rate, as assessed by cardiac dynamic ¹⁸ F-fluorodeoxyglucose-positron emission tomography (¹⁸ F-FDG-PET) combined with euglycaemic-hyperinsulinaemic clamp compared with glimepiride in patients with type 2 diabetes.

MATERIALS AND METHODS

To further investigate the cardioprotective mechanism of sodium-glucose co-transporter-2 inhibitors, we performed a 26-week, randomized, open-label, crossover, active-comparator study to determine the effects of empagliflozin 10 mg versus glimepiride 2 mg daily on the myocardial glucose metabolic rate assessed by cardiac dynamic ¹⁸ F-FDG-PET combined with euglycaemic-hyperinsulinaemic clamp in 23 patients with type 2 diabetes. We also measured cardiac geometry and myocardial mechano-energetic efficiency, as well as systolic and diastolic function by echocardiography.

RESULTS

Compared with glimepiride, treatment with empagliflozin resulted in a greater reduction in the myocardial glucose metabolic rate from baseline to 26 weeks (adjusted difference -6.07 [-8.59, -3.55] μmol/min/100 g; P < .0001). Moreover, compared with glimepiride, empagliflozin led to significant reductions in left atrial diameter, left ventricular end-systolic and end-diastolic volumes, N-terminal pro b-type natriuretic peptide levels, blood pressure, heart rate, stroke work, and myocardial oxygen consumption estimated by the rate pressure product, and increases in ejection fraction, myocardial mechano-energetic efficiency, red blood cells, and haematocrit and haemoglobin levels.

CONCLUSIONS

The present study provides evidence that empagliflozin treatment in subjects with type 2 diabetes without coronary artery disease leads to a significant reduction in the myocardial glucose metabolic rate.

Cardiorenal protection of SGLT2 inhibitors—Perspectives from metabolic reprogramming

Sodium-glucose co-transporter 2 (SGLT2) inhibitors, initially developed as a novel class of anti-hyperglycaemic drugs, have been shown to significantly improve metabolic indicators and protect the kidneys and heart of patients with or without type 2 diabetes mellitus. The possible mechanisms mediating these unexpected cardiorenal benefits are being extensively investigated because they cannot solely be attributed to improvements in glycaemic control. Notably, emerging data indicate that metabolic reprogramming is involved in the progression of cardiorenal metabolic diseases. SGLT2 inhibitors reprogram systemic metabolism to a fasting-like metabolic paradigm, involving the metabolic switch from carbohydrates to other energetic substrates and regulation of the related nutrient-sensing pathways, which might explain some of their cardiorenal protective effects. In this review, we will focus on the current understanding of cardiorenal protection by SGLT2 inhibitors, specifically its relevance to metabolic reprogramming.

Inhomogeneous Distribution of Regional Myocardial Work Efficiency Predicts Early Left Ventricular Remodeling After Acute Anterior Myocardial Infarction Treated With Primary Percutaneous Intervention

Background

This study aimed to investigate the hypothesis that specific pattern of myocardial work (MW) distribution in patients with acute anterior ST-segment elevation myocardial infarction (STEMI) could provide prognostic value for predicting left ventricular (LV) remodeling.

Methods

A total of 98 first anterior wall STEMI patients treated with primary percutaneous coronary intervention [85 men (86.7%), mean age: 58 ± 12 years] were enrolled. Transthoracic echocardiography was performed 24–72 h after angioplasty and during 3-month follow-up. MW was estimated from the left ventricular pressure–strain loop derived from speckle tracking echocardiography and simultaneous noninvasive brachial artery cuff pressure. The primary endpoint was early LV remodeling, defined as an increase in LV end-diastolic volume ≥20% compared with baseline at 3 months after STEMI. Major adverse cardiac events and combined clinical outcomes were recorded.

Results

LV remodeling was present in 32 patients (33%), who exhibited lower global and culprit-regional work index (WI), constructive work (CW), work efficiency (WE), and specifically, greater differences of WE (delta-WE) and CW (delta-CW) between the culprit and non-culprit region than those without LV remodeling both at the acute phase and follow-up (all P < 0.0125). During follow-up, all global and regional WI, CW, and WE were improved (P < 0.0125 compared with baseline), with less improvement in patients with LV remodeling. In multivariate analysis, baseline delta-WE (odds ratio: 2.304; 95% CI: 1.093–4.856, P = 0.028) and peak troponin I level (odds ratio: 1.035; 95%CI: 1.008–1.063, P = 0.010) were independently associated with early LV remodeling. Patients with greater delta-WE at baseline were associated with a higher incidence of heart failure and combined clinical outcomes during follow-up.

Conclusion

After reperfused acute anterior STEMI, patients with LV remodeling presented with more inhomogeneous MW distribution. The absolute difference of WE between culprit and non-culprit territory at the acute phase is an independent predictor for early LV remodeling.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier: NCT05107102.

The Role of Mitochondrial Abnormalities in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is defined as the presence in diabetic patients of abnormal cardiac structure and performance (such as left ventricular hypertrophy, fibrosis, and arrhythmia) in the absence of other cardiac risk factors (such as hypertension or coronary artery disease). Although the pathogenesis of DCM remains unclear currently, mitochondrial structural and functional dysfunctions are recognised as a central player in the DCM development. In this review, we focus on the role of mitochondrial dynamics, biogenesis and mitophagy, Ca²⁺ metabolism and bioenergetics in the DCM development and progression. Based on the crucial role of mitochondria in DCM, application of mitochondria-targeting therapies could be effective strategies to slow down the progression of the disease.

Mitochondrial Dynamics and Mitophagy in Cardiometabolic Disease

Mitochondria play a key role in cellular metabolism. Mitochondrial dynamics (fusion and fission) and mitophagy, are critical to mitochondrial function. Fusion allows organelles to share metabolites, proteins, and mitochondrial DNA, promoting complementarity between damaged mitochondria. Fission increases the number of mitochondria to ensure that they are passed on to their offspring during mitosis. Mitophagy is a process of selective removal of excess or damaged mitochondria that helps improve energy metabolism. Cardiometabolic disease is characterized by mitochondrial dysfunction, high production of reactive oxygen species, increased inflammatory response, and low levels of ATP. Cardiometabolic disease is closely related to mitochondrial dynamics and mitophagy. This paper reviewed the mechanisms of mitochondrial dynamics and mitophagy (focus on MFN1, MFN2, OPA1, DRP1, and PINK1 proteins) and their roles in diabetic cardiomyopathy, myocardial infarction, cardiac hypertrophy, heart failure, atherosclerosis, and obesity.

Defects in the Proteome and Metabolome in Human Hypertrophic Cardiomyopathy

BACKGROUND

Defects in energetics are thought to be central to the pathophysiology of hypertrophic cardiomyopathy (HCM); yet, the determinants of ATP availability are not known. The purpose of this study is to ascertain the nature and extent of metabolic reprogramming in human HCM, and its potential impact on contractile function.

METHODS

We conducted proteomic and targeted, quantitative metabolomic analyses on heart tissue from patients with HCM and from nonfailing control human hearts.

RESULTS

In the proteomic analysis, the greatest differences observed in HCM samples compared with controls were increased abundances of extracellular matrix and intermediate filament proteins and decreased abundances of muscle creatine kinase and mitochondrial proteins involved in fatty acid oxidation. These differences in protein abundance were coupled with marked reductions in acyl carnitines, byproducts of fatty acid oxidation, in HCM samples. Conversely, the ketone body 3-hydroxybutyrate, branched chain amino acids, and their breakdown products, were all significantly increased in HCM hearts. ATP content, phosphocreatine, nicotinamide adenine dinucleotide and its phosphate derivatives, NADP and NADPH, and acetyl CoA were also severely reduced in HCM compared with control hearts. Functional assays performed on human skinned myocardial fibers demonstrated that the magnitude of observed reduction in ATP content in the HCM samples would be expected to decrease the rate of cross-bridge detachment. Moreover, left atrial size, an indicator of diastolic compliance, was inversely correlated with ATP content in hearts from patients with HCM.

CONCLUSIONS

HCM hearts display profound deficits in nucleotide availability with markedly reduced capacity for fatty acid oxidation and increases in ketone bodies and branched chain amino acids. These results have important therapeutic implications for the future design of metabolic modulators to treat HCM.

Midpoint of energy intake, non-fasting time and cardiorespiratory fitness in heart failure with preserved ejection fraction and obesity

BACKGROUND

Delayed time of evening meal is associated with favorable cardiorespiratory fitness (CRF) in patients with heart failure with preserved ejection fraction (HFpEF) and obesity. It is unknown, however, if increasing daily non-fasting time or delaying the midpoint of energy intake may also be associated with CRF.

OBJECTIVE

Our aim was to examine whether a longer non-fasting time, delayed midpoint of energy intake, or both, are associated with greater CRF in patients with HFpEF and obesity.

METHODS

We measured peak oxygen consumption (VO2), a measure of CRF, in 32 patients with HFpEF and obesity with cardiopulmonary exercise testing, and dietary intake using a five-pass 24-h dietary recall. Participants were divided into groups by having lesser (<11.6) or greater (≥11.6) periods of non-fasting time than the median and similarly, with earlier (<2:15 PM) or later (≥2:15 PM) than median midpoint of energy intake.

RESULTS

Median non-fasting time was 11.6 [10.6-12.9] hours and midpoint of energy intake was 2:15 [1:04-3:00] PM. There were no differences in CRF between those with a shorter (<11.6) or longer (≥11.6) non-fasting time. Participants with a delayed midpoint of energy intake (≥2:15 PM) had greater peak VO2 and exercise time. Midpoint of energy intake (r = 0.444, P = 0.011) and time of last meal (r = 0.550, P = 0.001) displayed a positive association with peak VO2, but not non-fasting time nor time of first meal.

CONCLUSIONS

Delaying the midpoint of energy intake by postponing last meal is associated with better peak VO2 and exercise time in patients with HFpEF and obesity.

The Emerging Role of Ferroptosis in Cardiovascular Diseases

Ferroptosis is one type of programmed cell death discovered in recent years, which is characterized by iron-dependent lipid peroxidation and participating in iron, lipid and antioxidant metabolism. Ferroptosis is different from the traditional cell death types such as apoptosis, necroptosis and autophagy in morphology, biochemistry and genetics. Cardiovascular diseases are considered as an important cause of death from non-communicable diseases in the global population and poses a serious threat to human health. Apoptosis has long been thought to be the major type of cardiomyocyte death, but now ferroptosis has been shown to play a major role in cardiovascular diseases as well. This review will discuss related issues such as the mechanisms of ferroptosis and its effects on the occurrence and development of cardiovascular diseases, aiming to provide a novel target for the prevention and treatment of cardiovascular diseases.

Diabetes Status Modifies the Association Between Different Measures of Obesity and Heart Failure Risk Among Older Adults: A Pooled Analysis of Community-Based NHLBI Cohorts

BACKGROUND

Obesity and diabetes are associated with a higher risk of heart failure (HF). The interrelationships between different measures of adiposity-overall obesity, central obesity, fat mass (FM)-and diabetes status for HF risk are not well-established.

METHODS

Participant-level data from the ARIC study (Atherosclerosis Risk in Communities; visit 5) and the CHS (Cardiovascular Health Study; visit 1) cohorts were obtained from the National Heart, Lung, and Blood Institute Biologic Specimen and Data Repository Information Coordinating Center, harmonized, and pooled for the present analysis, excluding individuals with prevalent HF. FM was estimated in all participants using established anthropometric prediction equations additionally validated using the bioelectrical impedance-based FM in the ARIC subgroup. Incident HF events on follow-up were captured across both cohorts using similar adjudication methods. Multivariable-adjusted Fine-Gray models were created to evaluate the associations of body mass index (BMI), waist circumference (WC), and FM with risk of HF in the overall cohort as well as among those with versus without diabetes at baseline. The population attributable risk of overall obesity (BMI≥30 kg/m²), abdominal obesity (WC>88 and 102 cm in women and men, respectively), and high FM (above sex-specific median) for incident HF was evaluated among participants with and without diabetes.

RESULTS

The study included 10 387 participants (52.9% ARIC; 25.1% diabetes; median age, 74 years). The correlation between predicted and bioelectrical impedance-based FM was high (R²=0.90; n=5038). During a 5-year follow-up, 447 participants developed HF (4.3%). Higher levels of each adiposity measure were significantly associated with higher HF risk (hazard ratio [95% CI] per 1 SD higher BMI=1.15 [1.05, 1.27], WC=1.22 [1.10, 1.36]; FM=1.13 [1.02, 1.25]). A significant interaction was noted between diabetes status and measures of BMI (P interaction=0.04) and WC (P interaction=0.004) for the risk of HF. In stratified analysis, higher measures of each adiposity parameter were significantly associated with higher HF risk in individuals with diabetes (hazard ratio [95% CI] per 1 SD higher BMI=1.29 [1.14-1.47]; WC=1.48 [1.29-1.70]; FM=1.25 [1.09-1.43]) but not those without diabetes, including participants with prediabetes and euglycemia. The population attributable risk percentage of overall obesity, abdominal obesity, and high FM for incident HF was higher among participants with diabetes (12.8%, 29.9%, and 13.7%, respectively) versus those without diabetes (≤1% for each).

CONCLUSIONS

Higher BMI, WC, and FM are strongly associated with greater risk of HF among older adults, particularly among those with prevalent diabetes.

SGLT2 Inhibitors and Ketone Metabolism in Heart Failure

Sodium-glucose cotransporter-2 (SGLT2) inhibitors have emerged as powerful drugs that can be used to treat heart failure (HF) patients, both with preserved and reduced ejection fraction and in the presence or absence of type 2 diabetes. While the mechanisms underlying the salutary effects of SGLT2 inhibitors have not been fully elucidated, there is clear evidence for a beneficial metabolic effect of these drugs. In this review, we discuss the effects of SGLT2 inhibitors on cardiac energy provision secondary to ketone bodies, pathological ventricular remodeling, and inflammation in patients with HF. While the specific contribution of ketone bodies to the pleiotropic cardiovascular benefits of SGLT2 inhibitors requires further clarification, ketone bodies themselves may also be used as a therapy for HF.

Sodium Glucose Cotransporter Type 2 Inhibitors Improve Cardiorenal Outcome of Patients With Coronary Artery Disease: A Meta-Analysis

OBJECTIVE

Sodium glucose cotransporter type 2 inhibitors (SGLT-2i) are beneficial for cardiorenal outcomes in patients with type 2 diabetes mellitus (T2DM), heart failure (HF) or chronic kidney disease (CKD). However, whether or not the patients with coronary artery disease (CAD) have prognostic benefit from SGLT-2i treatment has not been fully studied. The purpose of this meta-analysis is to determine the prognostic benefit of SGLT-2i administration in CAD patients.

METHODS

We searched the PubMed, Embase and Cochrane Library from inception until October 15, 2021. We included randomized controlled trials (RCTs) reporting the effect of SGLT-2i on major adverse cardiovascular event (MACE), hospitalization for heart failure (HHF), cardiovascular (CV) death and cardiorenal parameters in CAD patients. Hazard ratio (HR) with 95% confidence interval (CI) and mean difference (MD) from trials were meta-analyzed using fixed-effects models.

RESULTS

Nine trials enrolling 15,301 patients with CAD were included in the analyses. Overall, SGLT2i were associated with a reduced risk of MACE (HR: 0.84; 95% CI 0.74-0.95; I² = 0%), HHF (HR: 0.69; 95% CI 0.58-0.83; I² = 0%) and a composite of CV death or HHF (HR: 0.78; 95% CI 0.71-0.86; I² = 37%) in CAD patients. Compared with control group, estimated glomerular filtration rate (eGFR) level decreased less in SGLT-2i group (mean difference [MD] = -3.60, 95% CI, -5.90 to -1.30, p = 0.002; I² = 0%).

CONCLUSIONS

SGLT-2i can improve cardiorenal outcomes in CAD patients. Further RCTs and real world studies are need to investigate the effect of SGLT2i on CAD patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42021258237.

Inhibition of Jumonji demethylases reprograms severe dilated cardiomyopathy and prolongs survival

Hypertrophic/dilated cardiomyopathy, often a prequel to heart failure, is accompanied by maladaptive transcriptional changes that contribute to arrythmias and contractile misfunction. Transgenic mice constitutively expressing high levels of calcineurin are known to develop extreme heart hypertrophy, which progresses to dilated cardiomyopathy, and to die several weeks after birth. Here, we characterized aberrant transcriptional and epigenetic pathways in this mouse model and established a pharmacological approach to treat established cardiomyopathy. We found that H3K4me3 (trimethyl histone 3 lysine 4) and H3K9me3 (trimethyl histone 3 lysine 9) Jumonji histone demethylases are markedly increased at the protein level and show enhanced enzymatic activity in diseased hearts. These epigenetic regulators continued to increase with time, further affecting cardiac gene expression. Our findings parallel the lower H3K4me3 and H3K9me3 levels seen in human patients. Inhibition of Jumonji demethylase activities in vivo results in lower histone demethylase enzymatic function in the heart and higher histone methylation levels and leads to partial reduction of heart size, reversal of maladaptive transcriptional programs, improved heart function, and prolonged survival. At the molecular level, target genes of transcription factor myocyte enhancer factor 2 are specifically regulated in response to pharmacological or genetic inhibition of Jumonji demethylases. Similar transcriptional reversal of disease-associated genes is seen in a second disease model based on cardiac mechanical overload. Our findings validate pharmacological inhibitors of Jumonji demethylases as potential therapeutics for the treatment of cardiomyopathies across disease models and provide evidence of the reversal of maladaptive transcriptional reprogramming leading to partial restoration of cardiac function. In addition, this study defines pathways of therapeutic resistance upregulated with disease progression.

Traditional Chinese medicine enhances myocardial metabolism during heart failure

The prognosis of various cardiovascular diseases eventually leads to heart failure (HF). An energy metabolism disorder of cardiomyocytes is important in explaining the molecular basis of HF; this will aid global research regarding treatment options for HF from the perspective of myocardial metabolism. There are many drugs to improve myocardial metabolism for the treatment of HF, including angiotensin receptor blocker-neprilysin inhibitor (ARNi) and sodium glucose cotransporter 2 (SGLT-2) inhibitors. Although Western medicine has made considerable progress in HF therapy, the morbidity and mortality of the disease remain high. Therefore, HF has attracted attention from researchers worldwide. In recent years, the application of traditional Chinese medicine (TCM) in HF treatment has been gradually accepted, and many studies have investigated the mechanism whereby TCM improves myocardial metabolism; the TCMs studied include Danshen yin, Fufang Danshen dripping pill, and Shenmai injection. This enables the clinical application of TCM in the treatment of HF by improving myocardial metabolism. We systematically reviewed the efficacy of TCM for improving myocardial metabolism during HF as well as the pharmacological effects of active TCM ingredients on the cardiovascular system and the potential mechanisms underlying their ability to improve myocardial metabolism. The results indicate that TCM may serve as a complementary and alternative approach for the prevention of HF. However, further rigorously designed randomized controlled trials are warranted to assess the effect of TCM on long-term hard endpoints in patients with cardiovascular disease.

Treatments for skeletal muscle abnormalities in heart failure: sodium-glucose transporter 2 and ketone bodies

Various skeletal muscle abnormalities are known to occur in heart failure (HF), and are closely associated with exercise intolerance. Particularly, abnormal energy metabolism caused by mitochondrial dysfunction in skeletal muscle is a cause of decreased endurance exercise capacity. However, to date, no specific drug treatment has been established for the skeletal muscle abnormalities and exercise intolerance occurring in HF patients. Sodium-glucose transporter 2 (SGLT2) inhibitors promote glucose excretion by suppressing glucose reabsorption in the renal tubules, which has a hypoglycemic effect independent of insulin secretion. Recently, large clinical trials have demonstrated that treatment with SGLT2 inhibitors suppresses cardiovascular events in patients who have HF with systolic dysfunction. Mechanisms of the therapeutic effects of SGLT2 inhibitors for HF have been suggested to be diuretic, suppression of neurohumoral factor activation, renal protection, and improvement of myocardial metabolism, but has not been clarified to date. SGLT2 inhibitors are known to increase blood ketone bodies. This suggests that they may improve the abnormal skeletal muscle metabolism in HF, i.e., improve fatty acid metabolism, suppress glycolysis, and utilize ketone bodies in mitochondrial energy production. Ultimately, they may improve aerobic metabolism in skeletal muscle, and suppress anaerobic metabolism and improve aerobic exercise capacity at the level of the anaerobic threshold. The potential actions of such SGLT2 inhibitors explain their effectiveness in HF, and may be candidates for new drug treatments aimed at improving exercise intolerance. In this review, we outlined the effects of SGLT2 inhibitors on skeletal muscle metabolism, with a particular focus on ketone metabolism.