Metabolomic analysis of pressure-overloaded and infarcted mouse hearts

Mechanisms of stretch-induced electro-anatomical remodeling and atrial arrhythmogenesis

Atrial fibrillation (AF) is the most common cardiac rhythm disorder, often occurring in the setting of atrial distension and elevated myocardialstretch. While various mechano-electrochemical signal transduction pathways have been linked to AF development and progression, the underlying molecular mechanisms remain poorly understood, hampering AF therapies. In this review, we describe different aspects of stretch-induced electro-anatomical remodeling as seen in animal models and in patients with AF. Specifically, we focus on cellular and molecular mechanisms that are responsible for mechano-electrochemical signal transduction and the development of ectopic beats triggering AF from pulmonary veins, the most common source of paroxysmal AF. Furthermore, we describe structural changes caused by stretch occurring before and shortly after the onset of AF as well as during AF progression, contributing to longstanding forms of AF. We also propose mechanical stretch as a new dimension to the concept "AF begets AF", in addition to underlying diseases. Finally, we discuss the mechanisms of these electro-anatomical alterations in a search for potential therapeutic strategies and the development of novel antiarrhythmic drugs targeted at the components of mechano-electrochemical signal transduction not only in cardiac myocytes, but also in cardiac non-myocyte cells.

The role of BCAA metabolism in metabolic health and disease

It has long been postulated that dietary restriction is beneficial for ensuring longevity and extending the health span of mammals, including humans. In particular, a reduction in protein consumption has been shown to be specifically linked to the beneficial effect of dietary restriction on metabolic disorders, presumably by reducing the activity of the mechanistic target of rapamycin complex (mTORC) 1 and the reciprocal activation of AMP-activated protein kinase (AMPK) and sirtuin pathways. Although it is widely used as a dietary supplement to delay the aging process in humans, recent evidence suggests that branched-chain amino acids (BCAAs) might be a major cause of the deteriorating effect of a protein diet on aging and related disorders. In this review, we delineate the regulation of metabolic pathways for BCAAs at the tissue-specific level and summarize recent findings regarding the role of BCAAs in the control of metabolic health and disease in mammals.

Duality of Branched-Chain Amino Acids in Chronic Cardiovascular Disease: Potential Biomarkers versus Active Pathophysiological Promoters

Branched-chain amino acids (BCAAs), comprising leucine (Leu), isoleucine (Ile), and valine (Val), are essential nutrients vital for protein synthesis and metabolic regulation via specialized signaling networks. Their association with cardiovascular diseases (CVDs) has become a focal point of scientific debate, with emerging evidence suggesting both beneficial and detrimental roles. This review aims to dissect the multifaceted relationship between BCAAs and cardiovascular health, exploring the molecular mechanisms and clinical implications. Elevated BCAA levels have also been linked to insulin resistance (IR), type 2 diabetes mellitus (T2DM), inflammation, and dyslipidemia, which are well-established risk factors for CVD. Central to these processes are key pathways such as mammalian target of rapamycin (mTOR) signaling, nuclear factor kappa-light-chain-enhancer of activate B cells (NF-κB)-mediated inflammation, and oxidative stress. Additionally, the interplay between BCAA metabolism and gut microbiota, particularly the production of metabolites like trimethylamine-N-oxide (TMAO), adds another layer of complexity. Contrarily, some studies propose that BCAAs may have cardioprotective effects under certain conditions, contributing to muscle maintenance and metabolic health. This review critically evaluates the evidence, addressing the biological basis and signal transduction mechanism, and also discusses the potential for BCAAs to act as biomarkers versus active mediators of cardiovascular pathology. By presenting a balanced analysis, this review seeks to clarify the contentious roles of BCAAs in CVD, providing a foundation for future research and therapeutic strategies required because of the rising prevalence, incidence, and total burden of CVDs.

Empagliflozin, a sodium-glucose cotransporter inhibitor enhancing mitochondrial action and cardioprotection in metabolic syndrome

Metabolic syndrome (MetS) has a large clinical population nowadays, usually due to excessive energy intake and lack of exercise. During MetS, excess nutrients stress the mitochondria, resulting in relative hypoxia in tissues and organs, even when blood supply is not interrupted or reduced, making mitochondrial dysfunction a central pathogenesis of cardiovascular disease in the MetS. Sodium-glucose cotransporter 2 inhibitors were designed as a hyperglycemic drug that acts on the renal tubules to block sugar reabsorption in primary urine. Recently they have been shown to have anti-inflammatory and other protective effects on cardiomyocytes in MetS, and have also been recommended in the latest heart failure guidelines as a routine therapy. Among these inhibitors, empagliflozin shows better clinical promise due to less influence from glomerular filtration rate. This review focuses on the mitochondrial mechanisms of empagliflozin, which underlie the anti-inflammatory and recover cellular functions in MetS cardiomyocytes, including stabilizing calcium concentration, mediating metabolic reprogramming, maintaining homeostasis of mitochondrial quantity and quality, stable mitochondrial DNA copy number, and repairing damaged mitochondrial DNA.

Tyrosine to threonine ratio was related to heart failure with reduced or mildly reduced ejection fraction

AIMS

We aim to explore the associations between serum tyrosine (Tyr) to threonine (Thr) ratio and chronic heart failure (HF) with reduced or mildly reduced ejection fraction (EF) (HFrEF or HFmrEF).

METHODS AND RESULTS

The study recruited 418 subjects (77.5% males, mean age 65.2 ± 12.5 years), including 318 HF subjects (HFrEF or HFmrEF) and 100 cardiovascular subjects without acute or chronic HF [including heart failure with preserved ejection fraction (HFpEF)] as controls. Serum levels of 21 kinds of amino acids (AAs) were measured by mass spectrometry. Logistic regression analysis was conducted to measuring the association between the AAs levels and the presence of HF. Event-free survival was determined by Kaplan-Meier curves and differences in survival were assessed using log-rank tests. Cox regression analysis was used to assess the prognostic value of AAs in HF. Receiver-operating characteristic (ROC) curve was performed to further confirm regression analysis. Along with the control, HFmrEF, and HFrEF subjects, serum tyrosine (Tyr) gradually increased (64.43 ± 15.28 μmol/L vs. 71.79 ± 18.74 μmol/L vs. 77.32 ± 25.90 μmol/L, P < 0.001) while serum threonine (Thr) decreased (165.21 ± 40.09 μmol/L vs. 144.93 ± 44.56 μmol/L vs. 135.25 ± 41.25 μmol/L, P < 0.001). Tyr/Thr ratio was the independent risk factor for the presence of HF in all subjects [odds ratio (OR), 3.510; 95% confidence interval (CI): 2.445-5.040; P < 0.001]. After following up for a mean year (11.10 ± 2.80 months) in 269 HF subjects (75.1% males, mean age 65.2 ± 12.8 years), the higher Tyr/Thr ratio was associated with a higher risk of HF endpoint events in HF subjects [hazard ratio (HR), 2.901; 95% CI: 1.228-6.851; P = 0.015]. By comparing the area under the receiver-operating characteristic curve (AUC), Tyr/Thr ratio was superior to Fischer's ratio (FR) in predicting HF occurrence (0.767:0.573, P < 0.001) or cardiovascular (CV) death (0.715:0.550, P = 0.047).

CONCLUSIONS

Circulating elevated Tyr/Thr ratio confer an increased risk for the presence of HF and poor prognosis. Tyr/Thr index outweighs FR index in predicting HF occurrence or CV death.

Exercise-induced changes in myocardial glucose utilization during periods of active cardiac growth

Exercise training can promote physiological cardiac growth, which has been suggested to involve changes in glucose metabolism to facilitate hypertrophy of cardiomyocytes. In this study, we used a dietary, in vivo isotope labeling approach to examine how exercise training influences the metabolic fate of carbon derived from dietary glucose in the heart during acute, active, and established phases of exercise-induced cardiac growth. Male and female FVB/NJ mice were subjected to treadmill running for up to 4 weeks and cardiac growth was assessed by gravimetry. Cardiac metabolic responses to exercise were assessed via in vivo tracing of [13C6]-glucose via mass spectrometry and nuclear magnetic resonance. We found that the half-maximal cardiac growth response was achieved by approximately 1 week of daily exercise training, with near maximal growth observed in male mice with 2 weeks of training; however, female mice were recalcitrant to exercise-induced cardiac growth and required a higher daily intensity of exercise training to achieve significant, albeit modest, increases in cardiac mass. We also found that increases in the energy charge of adenylate and guanylate nucleotide pools precede exercise-induced changes in cardiac size and were associated with higher glucose tracer enrichment in the TCA pool and in amino acids (aspartate, glutamate) sourced by TCA intermediates. Our data also indicate that the activity of collateral biosynthetic pathways of glucose metabolism may not be markedly altered by exercise. Overall, this study provides evidence that metabolic remodeling in the form of heightened energy charge and increased TCA cycle activity and cataplerosis precedes cardiac growth caused by exercise training in male mice.

Hippo pathway activated by circulating reactive oxygen species mediates cardiac diastolic dysfunction after acute kidney injury

Acute kidney injury (AKI) can cause distal cardiac dysfunction; however, the underlying mechanism is unknown. Oxidative stress is proved prominent in AKI-induced cardiac dysfunction, and a possible bridge role of oxidative-stress products in cardio-renal interaction has been reported. Therefore, this study aimed to investigate the critical role of circulating reactive oxygen species (ROS) in mediating cardiac dysfunction after bilateral renal ischemia-reperfusion injury (IRI). We observed the diastolic dysfunction in the mice following renal IRI, accompanied by reduced ATP levels, oxidative stress, and branched-chain amino acids (BCAA) accumulation in the heart. Notably, ROS levels showed a sequential increase in the kidneys, circulation, and heart. Treatment with tempol, an ROS scavenger, significantly restored cardiac diastolic function in the renal IRI mice, corroborating the bridge role of circulating ROS. Accumulating evidence has identified oxidative stress as upstream of Mst1/Hippo in cardiac injury, which could regulate the expression of downstream genes related to mitochondrial quality control, leading to lower ATP, higher ROS and metabolic disorder. To verify this, we examined the activation of the Mst1/Hippo pathway in the heart of renal IRI mice, which was alleviated by tempol treatment as well. In vitro, analysis revealed that Mst1-knockdown cardiomyocytes could be activated by hydrogen peroxide (H2O2). Analysis of Mst1-overexpression cardiomyocytes confirmed the critical role of the Mst1/Hippo pathway in oxidative stress and BCAA dysmetabolism. Therefore, our results indicated that circulating ROS following renal IRI activates the Mst1/Hippo pathway of myocardium, leading to cardiac oxidative stress and diastolic dysfunction. This finding provides new insights for the clinical exploration of improved treatment options for cardiorenal syndrome.

Metabolic Reprogramming: A Byproduct or a Driver of Cardiomyocyte Proliferation?

Defining mechanisms of cardiomyocyte proliferation should guide the understanding of endogenous cardiac regeneration and could lead to novel treatments for diseases such as myocardial infarction. In the neonatal heart, energy metabolic reprogramming (phenotypic alteration of glucose, fatty acid, and amino acid metabolism) parallels cell cycle arrest of cardiomyocytes. The metabolic reprogramming occurring shortly after birth is associated with alterations in blood oxygen levels, metabolic substrate availability, hemodynamic stress, and hormone release. In the adult heart, myocardial infarction causes metabolic reprogramming but these changes cannot stimulate sufficient cardiomyocyte proliferation to replace those lost by the ischemic injury. Some putative pro-proliferative interventions can induce the metabolic reprogramming. Recent data show that altering the metabolic enzymes PKM2 [pyruvate kinase 2], LDHA [lactate dehydrogenase A], PDK4 [pyruvate dehydrogenase kinase 4], SDH [succinate dehydrogenase], CPT1b [carnitine palmitoyl transferase 1b], or HMGCS2 [3-hydroxy-3-methylglutaryl-CoA synthase 2] is sufficient to partially reverse metabolic reprogramming and promotes adult cardiomyocyte proliferation. How metabolic reprogramming regulates cardiomyocyte proliferation is not clearly defined. The possible mechanisms involve biosynthetic pathways from the glycolysis shunts and the epigenetic regulation induced by metabolic intermediates. Metabolic manipulation could represent a new approach to stimulate cardiac regeneration; however, the efficacy of these manipulations requires optimization, and novel molecular targets need to be defined. In this review, we summarize the features, triggers, and molecular regulatory networks responsible for metabolic reprogramming and discuss the current understanding of metabolic reprogramming as a critical determinant of cardiomyocyte proliferation.

Metabolic profiling of aortic stenosis and hypertrophic cardiomyopathy identifies mechanistic contrasts in substrate utilization

Aortic stenosis (AS) and hypertrophic cardiomyopathy (HCM) are distinct disorders leading to left ventricular hypertrophy (LVH), but whether cardiac metabolism substantially differs between these in humans remains to be elucidated. We undertook an invasive (aortic root, coronary sinus) metabolic profiling in patients with severe AS and HCM in comparison with non-LVH controls to investigate cardiac fuel selection and metabolic remodeling. These patients were assessed under different physiological states (at rest, during stress induced by pacing). The identified changes in the metabolome were further validated by metabolomic and orthogonal transcriptomic analysis, in separately recruited patient cohorts. We identified a highly discriminant metabolomic signature in severe AS in all samples, regardless of sampling site, characterized by striking accumulation of long-chain acylcarnitines, intermediates of fatty acid transport across the inner mitochondrial membrane, and validated this in a separate cohort. Mechanistically, we identify a downregulation in the PPAR-α transcriptional network, including expression of genes regulating fatty acid oxidation (FAO). In silico modeling of β-oxidation demonstrated that flux could be inhibited by both the accumulation of fatty acids as a substrate for mitochondria and the accumulation of medium-chain carnitines which induce competitive inhibition of the acyl-CoA dehydrogenases. We present a comprehensive analysis of changes in the metabolic pathways (transcriptome to metabolome) in severe AS, and its comparison to HCM. Our results demonstrate a progressive impairment of β-oxidation from HCM to AS, particularly for FAO of long-chain fatty acids, and that the PPAR-α signaling network may be a specific metabolic therapeutic target in AS.

Targeted arginine metabolomics combined with metagenomics revealed the potential mechanism of Pueraria lobata extract in treating myocardial infarction

The extraction methods for traditional Chinese medicine (TCM) may have varying therapeutic effects on diseases. Currently, Pueraria lobata (PL) is mostly extracted with ethanol, but decoction, as a TCM extraction method, is not widely adopted. In this study, we present a strategy that integrates targeted metabolomics, 16 s rDNA sequencing technology and metagenomics for exploring the potential mechanism of the water extract of PL (PLE) in treating myocardial infarction (MI). Using advanced analytical techniques like ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), we comprehensively characterized PLE's chemical composition. Further, we tested its efficacy in a rat model of MI induced by ligation of the left anterior descending branch of the coronary artery (LAD). We assessed cardiac enzyme levels and conducted echocardiograms. UPLC-MS/MS was used to compare amino acid differences in serum. Furthermore, we investigated fecal samples using 16S rDNA sequencing and metagenomic sequencing to study intestinal flora diversity and function. This study demonstrated PLE's effectiveness in reducing cardiac injury in LAD-ligated rats. Amino acid metabolomics revealed significant improvements in serum levels of arginine, citrulline, proline, ornithine, creatine, creatinine, and sarcosine in MI rats, which are key compounds in the arginine metabolism pathway. Enzyme-linked immunosorbent assay (ELISA) results showed that PLE significantly improved arginase (Arg), nitric oxide synthase (NOS), and creatine kinase (CK) contents in the liver tissue of MI rats. 16 s rDNA and metagenome sequencing revealed that PLE significantly improved intestinal flora imbalance in MI rats, particularly in taxa such as Tuzzerella, Desulfovibrio, Fournierella, Oscillibater, Harryflintia, and Holdemania. PLE also improved the arginine metabolic pathway in the intestinal microorganisms of MI rats. The findings indicate that PLE effectively modulates MI-induced arginine levels and restores intestinal flora balance. This study, the first to explore the mechanism of action of PLE in MI treatment considering amino acid metabolism and intestinal flora, expands our understanding of the potential of PL in MI treatment. It offers fresh insights into the mechanisms of PL, guiding further research and development of PL-based medicines.

From Beats to Metabolism: the Heart at the Core of Interorgan Metabolic Cross Talk

The heart, once considered a mere blood pump, is now recognized as a multifunctional metabolic and endocrine organ. Its function is tightly regulated by various metabolic processes, at the same time it serves as an endocrine organ, secreting bioactive molecules that impact systemic metabolism. In recent years, research has shed light on the intricate interplay between the heart and other metabolic organs, such as adipose tissue, liver, and skeletal muscle. The metabolic flexibility of the heart and its ability to switch between different energy substrates play a crucial role in maintaining cardiac function and overall metabolic homeostasis. Gaining a comprehensive understanding of how metabolic disorders disrupt cardiac metabolism is crucial, as it plays a pivotal role in the development and progression of cardiac diseases. The emerging understanding of the heart as a metabolic and endocrine organ highlights its essential contribution to whole body metabolic regulation and offers new insights into the pathogenesis of metabolic diseases, such as obesity, diabetes, and cardiovascular disorders. In this review, we provide an in-depth exploration of the heart's metabolic and endocrine functions, emphasizing its role in systemic metabolism and the interplay between the heart and other metabolic organs. Furthermore, emerging evidence suggests a correlation between heart disease and other conditions such as aging and cancer, indicating that the metabolic dysfunction observed in these conditions may share common underlying mechanisms. By unraveling the complex mechanisms underlying cardiac metabolism, we aim to contribute to the development of novel therapeutic strategies for metabolic diseases and improve overall cardiovascular health.

Advances in Metabolic Remodeling and Intervention Strategies in Heart Failure

The heart is the most energy-demanding organ throughout the whole body. Perturbations or failure in energy metabolism contributes to heart failure (HF), which represents the advanced stage of various heart diseases. The poor prognosis and huge economic burden associated with HF underscore the high unmet need to explore novel therapies targeting metabolic modulators beyond conventional approaches focused on neurohormonal and hemodynamic regulators. Emerging evidence suggests that alterations in metabolic substrate reliance, metabolic pathways, metabolic by-products, and energy production collectively regulate the occurrence and progression of HF. In this review, we provide an overview of cardiac metabolic remodeling, encompassing the utilization of free fatty acids, glucose metabolism, ketone bodies, and branched-chain amino acids both in the physiological condition and heart failure. Most importantly, the latest advances in pharmacological interventions are discussed as a promising therapeutic approach to restore cardiac function, drawing insights from recent basic research, preclinical and clinical studies.

Anemarrhena asphodeloides Bunge total saponins ameliorate diabetic cardiomyopathy by modifying the PI3K/AKT/HIF-1α pathway to restore glycolytic metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Based on the theory of traditional Chinese medicine (TCM), diabetic cardiomyopathy (DCM) belongs to the category of "Xiaoke disease" according to the symptoms, and "stasis-heat" is the main pathogenesis of DCM. The Chinese medicine Anemarrhena asphodeloides Bunge (AAB), as a representative of heat-clearing and engendering fluid, is often used clinically in the treatment of DCM. Anemarrhena asphodeloides Bunge total saponins (RATS) are the main bioactive components of AAB, the modern pharmacologic effects of RATS are anti-inflammatory, hypoglycemic, and cardioprotective. However, the potential protective mechanisms of RATS against DCM remain largely undiscovered.

AIM OF THE STUDY

The primary goal of this study was to explore the effect of RATS on DCM and its mechanism of action.

MATERIALS AND METHODS

Streptozotocin and a high-fat diet were used to induce DCM in rats. UHPLC/Q-TOF-MS was used to determine the chemical components of RATS. The degenerative alterations and apoptotic cells in the heart were assessed by HE staining and TUNEL. Network pharmacology was used to anticipate the probable targets and important pathways of RATS. The alterations in metabolites and main metabolic pathways in heart tissue were discovered using 1 H-NMR metabolomics. Ultimately, immunohistochemistry was used to find critical pathway protein expression.

RESULTS

First of all, UHPLC/Q-TOF-MS analysis showed that RATS contained 11 active ingredients. In animal experiments, we found that RATS lowered blood glucose and lipid levels in DCM rats, and alleviated cardiac pathological damage, and decreased cardiomyocyte apoptosis. Furthermore, the study found that RATS effectively reduced inflammatory factor release and the level of oxidative stress. Mechanistically, RATS downregulated the expression levels of PI3K, AKT, HIF-1α, LDHA, and GLUT4 proteins. Additionally, glycolysis was discovered to be a crucial pathway for RATS in the therapy of DCM.

CONCLUSIONS

Our findings suggest that the protective effect of RATS on DCM may be attributed to the inhibition of the PI3K/AKT/HIF-1α pathway and the correction of glycolytic metabolism.

Phenotypic flexibility in metabolic adjustments and digestive function in white-shouldered starlings: responses to short-term temperature acclimation

Changing the intrinsic rate of metabolic heat production is the main adaptive strategy for small birds to cope with different ambient temperatures. In this study, we tested the hypothesis that the small passerine the white-shouldered starling (Sturnus sinensis) can modulate basal metabolism under temperature acclimation by changing the morphological, physiological and biochemical state of its tissues and organs. We measured the effects of temperature on body mass, basal metabolic rate (BMR), wet mass of various internal organs, state 4 respiration (S4R) and cytochrome c oxidase (CCO) activity in the pectoral muscle and organs, metabolites in the pectoral muscle, energy intake, histological dynamics and the activity of duodenal digestive enzymes. Warm acclimation decreased BMR to a greater extent than cold acclimation. At the organ level, birds in the cold-acclimated group had significantly heavier intestines but significantly lighter pectoral muscles. At the cellular level, birds in the cold-acclimated group showed significantly higher S4R in the liver and heart and CCO activity in the liver and kidney at both the mass-specific and whole-organ levels. A metabolomic analysis of the pectoral tissue revealed significantly higher lipid decomposition, amino acid degradation, ATP hydrolysis, and GTP and biotin synthesis in cold-acclimated birds. Acclimation to cold significantly increased the gross energy intake (GEI), feces energy (FE) and digestive energy intake (DEI) but significantly decreased the digestive efficiency of these birds. Furthermore, cold-acclimated birds had a higher maltase activity and longer villi in the duodenum. Taken together, these data show that white-shouldered starlings exhibit high phenotypic flexibility in metabolic adjustments and digestive function under temperature acclimation, consistent with the notion that small birds cope with the energy challenges presented by a cold environment by modulating tissue function in a way that would affect BMR.

Cardiac Metabolism

The heart is composed of a heterogeneous mixture of cellular components perfectly intermingled and able to integrate common environmental signals to ensure proper cardiac function and performance. Metabolism defines a cell context-dependent signature that plays a critical role in survival, proliferation, or differentiation, being a recognized master piece of organ biology, modulating homeostasis, disease progression, and adaptation to tissue damage. The heart is a highly demanding organ, and adult cardiomyocytes require large amount of energy to fulfill adequate contractility. However, functioning under oxidative mitochondrial metabolism is accompanied with a concomitant elevation of harmful reactive oxygen species that indeed contributes to the progression of several cardiovascular pathologies and hampers the regenerative capacity of the mammalian heart. Cardiac metabolism is dynamic along embryonic development and substantially changes as cardiomyocytes mature and differentiate within the first days after birth. During early stages of cardiogenesis, anaerobic glycolysis is the main energetic program, while a progressive switch toward oxidative phosphorylation is a hallmark of myocardium differentiation. In response to cardiac injury, different signaling pathways participate in a metabolic rewiring to reactivate embryonic bioenergetic programs or the utilization of alternative substrates, reflecting the flexibility of heart metabolism and its central role in organ adaptation to external factors. Despite the well-established metabolic pattern of fetal, neonatal, and adult cardiomyocytes, our knowledge about the bioenergetics of other cardiac populations like endothelial cells, cardiac fibroblasts, or immune cells is limited. Considering the close intercellular communication and the influence of nonautonomous cues during heart development and after cardiac damage, it will be fundamental to better understand the metabolic programs in different cardiac cells in order to develop novel interventional opportunities based on metabolic rewiring to prevent heart failure and improve the limited regenerative capacity of the mammalian heart.

Raising NAD+ Level Stimulates Short-Chain Dehydrogenase/Reductase Proteins to Alleviate Heart Failure Independent of Mitochondrial Protein Deacetylation

BACKGROUND

Strategies to increase cellular NAD+ (oxidized nicotinamide adenine dinucleotide) level have prevented cardiac dysfunction in multiple models of heart failure, but molecular mechanisms remain unclear. Little is known about the benefits of NAD+-based therapies in failing hearts after the symptoms of heart failure have appeared. Most pretreatment regimens suggested mechanisms involving activation of sirtuin, especially Sirt3 (sirtuin 3), and mitochondrial protein acetylation.

METHODS

We induced cardiac dysfunction by pressure overload in SIRT3-deficient (knockout) mice and compared their response with nicotinamide riboside chloride treatment with wild-type mice. To model a therapeutic approach, we initiated the treatment in mice with established cardiac dysfunction.

RESULTS

We found nicotinamide riboside chloride improved mitochondrial function and blunted heart failure progression. Similar benefits were observed in wild-type and knockout mice. Boosting NAD+ level improved the function of NAD(H) redox-sensitive SDR (short-chain dehydrogenase/reductase) family proteins. Upregulation of Mrpp2 (mitochondrial ribonuclease P protein 2), a multifunctional SDR protein and a subunit of mitochondrial ribonuclease P, improves mitochondrial DNA transcripts processing and electron transport chain function. Activation of SDRs in the retinol metabolism pathway stimulates RXRα (retinoid X receptor α)/PPARα (proliferator-activated receptor α) signaling and restores mitochondrial oxidative metabolism. Downregulation of Mrpp2 and impaired mitochondrial ribonuclease P were found in human failing hearts, suggesting a shared mechanism of defective mitochondrial biogenesis in mouse and human heart failure.

CONCLUSIONS

These findings identify SDR proteins as important regulators of mitochondrial function and molecular targets of NAD+-based therapy. Furthermore, the benefit is observed regardless of Sirt3-mediated mitochondrial protein deacetylation, a widely held mechanism for NAD+-based therapy for heart failure. The data also show that NAD+-based therapy can be useful in pre-existing heart failure.

Blood-Derived Lipid and Metabolite Biomarkers in Cardiovascular Research from Clinical Studies: A Recent Update

The primary prevention, early detection, and treatment of cardiovascular disease (CVD) have been long-standing scientific research goals worldwide. In the past decades, traditional blood lipid profiles have been routinely used in clinical practice to estimate the risk of CVDs such as atherosclerotic cardiovascular disease (ASCVD) and as treatment targets for the primary prevention of adverse cardiac events. These blood lipid panel tests often fail to fully predict all CVD risks and thus need to be improved. A comprehensive analysis of molecular species of lipids and metabolites (defined as lipidomics and metabolomics, respectively) can provide molecular insights into the pathophysiology of the disease and could serve as diagnostic and prognostic indicators of disease. Mass spectrometry (MS) and nuclear magnetic resonance (NMR)-based lipidomics and metabolomics analysis have been increasingly used to study the metabolic changes that occur during CVD pathogenesis. In this review, we provide an overview of various MS-based platforms and approaches that are commonly used in lipidomics and metabolomics workflows. This review summarizes the lipids and metabolites in human plasma/serum that have recently (from 2018 to December 2022) been identified as promising CVD biomarkers. In addition, this review describes the potential pathophysiological mechanisms associated with candidate CVD biomarkers. Future studies focused on these potential biomarkers and pathways will provide mechanistic clues of CVD pathogenesis and thus help with the risk assessment, diagnosis, and treatment of CVD.

Extracellular Matrix Protein-1 as a Mediator of Inflammation-Induced Fibrosis After Myocardial Infarction

Irreversible fibrosis is a hallmark of myocardial infarction (MI) and heart failure. Extracellular matrix protein-1 (ECM-1) is up-regulated in these hearts, localized to fibrotic, inflammatory, and perivascular areas. ECM-1 originates predominantly from fibroblasts, macrophages, and pericytes/vascular cells in uninjured human and mouse hearts, and from M1 and M2 macrophages and myofibroblasts after MI. ECM-1 stimulates fibroblast-to-myofibroblast transition, up-regulates key fibrotic and inflammatory pathways, and inhibits cardiac fibroblast migration. ECM-1 binds HuCFb cell surface receptor LRP1, and LRP1 inhibition blocks ECM-1 from stimulating fibroblast-to-myofibroblast transition, confirming a novel ECM-1-LRP1 fibrotic signaling axis. ECM-1 may represent a novel mechanism facilitating inflammation-fibrosis crosstalk.

Metabolic Control of Cardiomyocyte Cell Cycle

Current therapies for heart failure aim to prevent the deleterious remodeling that occurs after MI injury, but currently no therapies are available to replace lost cardiomyocytes. Several organisms now being studied are capable of regenerating their myocardium by the proliferation of existing cardiomyocytes. In this review, we summarize the main metabolic pathways of the mammalian heart and how modulation of these metabolic pathways through genetic and pharmacological approaches influences cardiomyocyte proliferation and heart regeneration.

Delayed metabolic disturbances in the myocardium after exertional heat stroke: contrasting effects of exertion and thermal load

Epidemiological studies report higher risks of cardiovascular disease in humans exposed to heat stroke earlier in life. Previously, we explored mechanistic links between heat stroke and developing cardiac abnormalities using a preclinical mouse model of exertional heat stroke (EHS). Profound metabolic abnormalities developed in the ventricles of females but not males after 2 wk of recovery. Here we tested whether this lack of response in males could be attributed to the lower exercise performances or reduced thermal loads they experienced with the same running protocol. We systematically altered environmental temperature (Te) during EHS to manipulate heat exposure and exercise performance in the males. Three groups of adult C57BL/6 male mice were studied: "EHS-34" (Te = 34°C), "EHS-41" (Te = 41°C), and "EHS-39.5" (Te = 39.5°C). Mice ran until symptom limitation (unconsciousness), reaching max core temperature (Tc,max). After a 2-wk recovery, the mice were euthanized, and the ventricles were removed for untargeted metabolomics. Results were compared against age-matched nonexercise controls. The EHS-34 mice greatly elevated their exercise performance but reached lower Tc,max and lower thermal loads. The EHS-41 mice exhibited equivalent thermal loads, exercise times, and Tc,max compared with EHS-39.5. The ventricles from EHS-34 mice exhibited the greatest metabolic disturbances in the heart, characterized by shifts toward glucose metabolism, reductions in acylcarnitines, increased amino acid metabolites, elevations in antioxidants, altered TCA cycle flux, and increased xenobiotics. In conclusion, delayed metabolic disturbances following EHS in male myocardium appear to be greatly amplified by higher levels of exertion in the heat, even with lower thermal loads and max core temperatures.NEW & NOTEWORTHY Epidemiological data demonstrate greater cardiovascular risk in patients with previous heat stroke exposure. Using a preclinical mouse model of exertional heat stroke, male mice were exposed to one of three environmental temperatures (Te) during exercise. Paradoxically, after 2 wk, the mice in the lowest Te, exhibiting the largest exercise response and lowest heat load, had the greatest ventricular metabolic disturbances. Metabolic outcomes resemble developing left ventricular hypertrophy or stress-induced heart disease.

Metabolomics reveals that PS-NPs promote lung injury by regulating prostaglandin B1 through the cGAS-STING pathway

Nanoplastics have been widely studied as environmental pollutants, which can accumulate in the human body through the food chain or direct contact. Research has shown that nanoplastics can affect the immune system and mitochondrial function, but the underlying mechanisms are unclear. Lungs and macrophages have important immune and metabolic functions. This study explored the effects of 100 nm PS-NPs on innate immunity, mitochondrial function, and cellular metabolism-related pathways in lung (BEAS-2B) cells and macrophages (RAW264.7). The results had shown that PS-NPs exposure caused a decrease in mitochondrial membrane potential, intracellular ROS accumulation, and Ca2+ overload, and activated the cGAS-STING signaling pathway related to innate immunity. These changes had been observed at concentrations of PS-NPs as low as 60 μg/mL, which might have been comparable to environmental levels. Non-target metabolomics and Western Blotting results confirmed that PS-NPs regulated prostaglandin B1 and other metabolites to cause cell damage through the cGAS-STING pathway. Supplementation of prostaglandin B1 alleviated the immune activation and metabolic disturbance caused by PS-NPs exposure. This study identified PS-NPs-induced innate immune activation, mitochondrial dysfunction, and metabolic toxicity pathways, providing new insights into the potential for adverse outcomes of NPs in human life.

Energy metabolism: A critical target of cardiovascular injury

Cardiovascular diseases are the main killers threatening human health. Many studies have shown that abnormal energy metabolism plays a key role in the occurrence and development of acute and chronic cardiovascular diseases. Regulating cardiac energy metabolism is a frontier topic in the treatment of cardiovascular diseases. However, we are not very clear about the choice of different substrates, the specific mechanism of energy metabolism participating in the course of cardiovascular disease, and how to develop appropriate drugs to regulate energy metabolism to treat cardiovascular disease. Therefore, this paper reviews how energy metabolism participates in cardiovascular pathophysiological processes and potential drugs aimed at interfering energy metabolism.It is expected to provide good suggestions for promoting the clinical prevention and treatment of cardiovascular diseases from the perspective of energy metabolism.

SGLT2 inhibitors: role in protective reprogramming of cardiac nutrient transport and metabolism

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce heart failure events by direct action on the failing heart that is independent of changes in renal tubular function. In the failing heart, nutrient transport into cardiomyocytes is increased, but nutrient utilization is impaired, leading to deficient ATP production and the cytosolic accumulation of deleterious glucose and lipid by-products. These by-products trigger downregulation of cytoprotective nutrient-deprivation pathways, thereby promoting cellular stress and undermining cellular survival. SGLT2 inhibitors restore cellular homeostasis through three complementary mechanisms: they might bind directly to nutrient-deprivation and nutrient-surplus sensors to promote their cytoprotective actions; they can increase the synthesis of ATP by promoting mitochondrial health (mediated by increasing autophagic flux) and potentially by alleviating the cytosolic deficiency in ferrous iron; and they might directly inhibit glucose transporter type 1, thereby diminishing the cytosolic accumulation of toxic metabolic by-products and promoting the oxidation of long-chain fatty acids. The increase in autophagic flux mediated by SGLT2 inhibitors also promotes the clearance of harmful glucose and lipid by-products and the disposal of dysfunctional mitochondria, allowing for mitochondrial renewal through mitochondrial biogenesis. This Review describes the orchestrated interplay between nutrient transport and metabolism and nutrient-deprivation and nutrient-surplus signalling, to explain how SGLT2 inhibitors reverse the profound nutrient, metabolic and cellular abnormalities observed in heart failure, thereby restoring the myocardium to a healthy molecular and cellular phenotype.

Progressive Cardiac Metabolic Defects Accompany Diastolic and Severe Systolic Dysfunction in Spontaneously Hypertensive Rat Hearts

Background Cardiac metabolic abnormalities are present in heart failure. Few studies have followed metabolic changes accompanying diastolic and systolic heart failure in the same model. We examined metabolic changes during the development of diastolic and severe systolic dysfunction in spontaneously hypertensive rats (SHR). Methods and Results We serially measured myocardial glucose uptake rates with dynamic 2-[18F] fluoro-2-deoxy-d-glucose positron emission tomography in vivo in 9-, 12-, and 18-month-old SHR and Wistar Kyoto rats. Cardiac magnetic resonance imaging determined systolic function (ejection fraction) and diastolic function (isovolumetric relaxation time) and left ventricular mass in the same rats. Cardiac metabolomics was performed at 12 and 18 months in separate rats. At 12 months, SHR hearts, compared with Wistar Kyoto hearts, demonstrated increased isovolumetric relaxation time and slightly reduced ejection fraction indicating diastolic and mild systolic dysfunction, respectively, and higher (versus 9-month-old SHR decreasing) 2-[18F] fluoro-2-deoxy-d-glucose uptake rates (Ki). At 18 months, only few SHR hearts maintained similar abnormalities as 12-month-old SHR, while most exhibited severe systolic dysfunction, worsening diastolic function, and markedly reduced 2-[18F] fluoro-2-deoxy-d-glucose uptake rates. Left ventricular mass normalized to body weight was elevated in SHR, more pronounced with severe systolic dysfunction. Cardiac metabolite changes differed between SHR hearts at 12 and 18 months, indicating progressive defects in fatty acid, glucose, branched chain amino acid, and ketone body metabolism. Conclusions Diastolic and severe systolic dysfunction in SHR are associated with decreasing cardiac glucose uptake, and progressive abnormalities in metabolite profiles. Whether and which metabolic changes trigger progressive heart failure needs to be established.

Circulating sphingolipids in heart failure

Lack of significant advancements in early detection and treatment of heart failure have precipitated the need for discovery of novel biomarkers and therapeutic targets. Over the past decade, circulating sphingolipids have elicited promising results as biomarkers that premonish adverse cardiac events. Additionally, compelling evidence directly ties sphingolipids to these events in patients with incident heart failure. This review aims to summarize the current literature on circulating sphingolipids in both human cohorts and animal models of heart failure. The goal is to provide direction and focus for future mechanistic studies in heart failure, as well as pave the way for the development of new sphingolipid biomarkers.

Cardiac Metabolism in Heart Failure and Implications for Uremic Cardiomyopathy

Chronic kidney disease is associated with an increased risk for the development and progression of cardiovascular disorders including hypertension, dyslipidemia, and coronary artery disease. Chronic kidney disease may also affect the myocardium through complex systemic changes, resulting in structural remodeling such as hypertrophy and fibrosis, as well as impairments in both diastolic and systolic function. These cardiac changes in the setting of chronic kidney disease define a specific cardiomyopathic phenotype known as uremic cardiomyopathy. Cardiac function is tightly linked to its metabolism, and research over the past 3 decades has revealed significant metabolic remodeling in the myocardium during the development of heart failure. Because the concept of uremic cardiomyopathy has only been recognized in recent years, there are limited data on metabolism in the uremic heart. Nonetheless, recent findings suggest overlapping mechanisms with heart failure. This work reviews key features of metabolic remodeling in the failing heart in the general population and extends this to patients with chronic kidney disease. The knowledge of similarities and differences in cardiac metabolism between heart failure and uremic cardiomyopathy may help identify new targets for mechanistic and therapeutic research on uremic cardiomyopathy.

Branched-Chain Amino Acid Metabolism in the Failing Heart

Branched-chain amino acids (BCAAs) are essential amino acids which have critical roles in protein synthesis and energy metabolism in the body. In the heart, there is a strong correlation between impaired BCAA oxidation and contractile dysfunction in heart failure. Plasma and myocardial levels of BCAA and their metabolites, namely branched-chain keto acids (BCKAs), are also linked to cardiac insulin resistance and worsening adverse remodelling in the failing heart. This review discusses the regulation of BCAA metabolism in the heart and the impact of depressed cardiac BCAA oxidation on cardiac energy metabolism, function, and structure in heart failure. While impaired BCAA oxidation in the failing heart causes the accumulation of BCAA and BCKA in the myocardium, recent evidence suggested that the BCAAs and BCKAs have divergent effects on the insulin signalling pathway and the mammalian target of the rapamycin (mTOR) signalling pathway. Dietary and pharmacological interventions that enhance cardiac BCAA oxidation and limit the accumulation of cardiac BCAAs and BCKAs have been shown to have cardioprotective effects in the setting of ischemic heart disease and heart failure. Thus, targeting cardiac BCAA oxidation may be a promising therapeutic approach for heart failure.

Targeting mitochondrial impairment for the treatment of cardiovascular diseases: From hypertension to ischemia-reperfusion injury, searching for new pharmacological targets

Mitochondria and mitochondrial proteins represent a group of promising pharmacological target candidates in the search of new molecular targets and drugs to counteract the onset of hypertension and more in general cardiovascular diseases (CVDs). Indeed, several mitochondrial pathways result impaired in CVDs, showing ATP depletion and ROS production as common traits of cardiac tissue degeneration. Thus, targeting mitochondrial dysfunction in cardiomyocytes can represent a successful strategy to prevent heart failure. In this context, the identification of new pharmacological targets among mitochondrial proteins paves the way for the design of new selective drugs. Thanks to the advances in omics approaches, to a greater availability of mitochondrial crystallized protein structures and to the development of new computational approaches for protein 3D-modelling and drug design, it is now possible to investigate in detail impaired mitochondrial pathways in CVDs. Furthermore, it is possible to design new powerful drugs able to hit the selected pharmacological targets in a highly selective way to rescue mitochondrial dysfunction and prevent cardiac tissue degeneration. The role of mitochondrial dysfunction in the onset of CVDs appears increasingly evident, as reflected by the impairment of proteins involved in lipid peroxidation, mitochondrial dynamics, respiratory chain complexes, and membrane polarization maintenance in CVD patients. Conversely, little is known about proteins responsible for the cross-talk between mitochondria and cytoplasm in cardiomyocytes. Mitochondrial transporters of the SLC25A family, in particular, are responsible for the translocation of nucleotides (e.g., ATP), amino acids (e.g., aspartate, glutamate, ornithine), organic acids (e.g. malate and 2-oxoglutarate), and other cofactors (e.g., inorganic phosphate, NAD⁺, FAD, carnitine, CoA derivatives) between the mitochondrial and cytosolic compartments. Thus, mitochondrial transporters play a key role in the mitochondria-cytosol cross-talk by leading metabolic pathways such as the malate/aspartate shuttle, the carnitine shuttle, the ATP export from mitochondria, and the regulation of permeability transition pore opening. Since all these pathways are crucial for maintaining healthy cardiomyocytes, mitochondrial carriers emerge as an interesting class of new possible pharmacological targets for CVD treatments.

Branched-chain amino acids in cardiovascular disease

Research conducted in the past 15 years has yielded crucial insights that are reshaping our understanding of the systems physiology of branched-chain amino acid (BCAA) metabolism and the molecular mechanisms underlying the close relationship between BCAA homeostasis and cardiovascular health. The rapidly evolving literature paints a complex picture, in which numerous tissue-specific and disease-specific modes of BCAA regulation initiate a diverse set of molecular mechanisms that connect changes in BCAA homeostasis to the pathogenesis of cardiovascular diseases, including myocardial infarction, ischaemia-reperfusion injury, atherosclerosis, hypertension and heart failure. In this Review, we outline the current understanding of the major factors regulating BCAA abundance and metabolic fate, highlight molecular mechanisms connecting impaired BCAA homeostasis to cardiovascular disease, discuss the epidemiological evidence connecting BCAAs with various cardiovascular disease states and identify current knowledge gaps requiring further investigation.

Protection against Doxorubicin-Induced Cardiotoxicity by Ergothioneine

Background: Anthracyclines such as doxorubicin remain a primary treatment for hematological malignancies and breast cancers. However, cardiotoxicity induced by anthracyclines, possibly leading to heart failure, severely limits their application. The pathological mechanisms of anthracycline-induced cardiac injury are believed to involve iron-overload-mediated formation of reactive oxygen species (ROS), mitochondrial dysfunction, and inflammation. The dietary thione, ergothioneine (ET), is avidly absorbed and accumulated in tissues, including the heart. Amongst other cytoprotective properties, ET was shown to scavenge ROS, decrease proinflammatory mediators, and chelate metal cations, including Fe²⁺, preventing them from partaking in redox activities, and may protect against mitochondrial damage and dysfunction. Plasma ET levels are also strongly correlated to a decreased risk of cardiovascular events in humans, suggesting a cardioprotective role. This evidence highlights ET's potential to counteract anthracycline cardiotoxicity. Methods and Findings: We investigated whether ET supplementation can protect against cardiac dysfunction in mice models of doxorubicin-induced cardiotoxicity and revealed that it had significant protective effects. Moreover, ET administration in a mouse breast cancer model did not exacerbate the growth of the tumor or interfere with the chemotherapeutic efficacy of doxorubicin. Conclusion: These results suggest that ET could be a viable co-therapy to alleviate the cardiotoxic effects of anthracyclines in the treatment of cancers.

Metabolomic Profiling in Patients with Different Hemodynamic Subtypes of Severe Aortic Valve Stenosis

Severe aortic stenosis (AS) is a common pathological condition in an ageing population imposing significant morbidity and mortality. Based on distinct hemodynamic features, i.e., ejection fraction (EF), transvalvular gradient and stroke volume, four different AS subtypes can be distinguished: (i) normal EF and high gradient, (ii) reduced EF and high gradient, (iii) reduced EF and low gradient, and (iv) normal EF and low gradient. These subtypes differ with respect to pathophysiological mechanisms, cardiac remodeling, and prognosis. However, little is known about metabolic changes in these different hemodynamic conditions of AS. Thus, we carried out metabolomic analyses in serum samples of 40 AS patients (n = 10 per subtype) and 10 healthy blood donors (controls) using ultrahigh-performance liquid chromatography-tandem mass spectroscopy. A total of 1293 biochemicals could be identified. Principal component analysis revealed different metabolic profiles in all of the subgroups of AS (All-AS) vs. controls. Out of the determined biochemicals, 48% (n = 620) were altered in All-AS vs. controls (p < 0.05). In this regard, levels of various acylcarnitines (e.g., myristoylcarnitine, fold-change 1.85, p < 0.05), ketone bodies (e.g., 3-hydroxybutyrate, fold-change 11.14, p < 0.05) as well as sugar metabolites (e.g., glucose, fold-change 1.22, p < 0.05) were predominantly increased, whereas amino acids (e.g., leucine, fold-change 0.8, p < 0.05) were mainly reduced in All-AS. Interestingly, these changes appeared to be consistent amongst all AS subtypes. Distinct differences between AS subtypes were found for metabolites belonging to hemoglobin metabolism, diacylglycerols, and dihydrosphingomyelins. These findings indicate that relevant changes in substrate utilization appear to be consistent for different hemodynamic subtypes of AS and may therefore reflect common mechanisms during AS-induced heart failure. Additionally, distinct metabolites could be identified to significantly differ between certain AS subtypes. Future studies need to define their pathophysiological implications.

Iron homeostasis in the heart: Molecular mechanisms and pharmacological implications

Iron is necessary for the life of practically all living things, yet it may also harm people toxically. Accordingly, humans and other mammals have evolved an effective and tightly regulatory system to maintain iron homeostasis in healthy tissues, including the heart. Iron deficiency is common in patients with heart failure, and is associated with worse prognosis in this population; while the prevalence of iron overload-related cardiovascular disorders is also increasing. Therefore, enhancing the therapy of patients with cardiovascular disorders requires a thorough understanding of iron homeostasis. Here, we give readers an overview of the fundamental mechanisms governing systemic iron homeostasis as well as the most recent knowledge about the intake, storage, use, and export of iron from the heart. Genetic mouse models used for investigation of iron metabolism in various in vivo scenarios are summarized and highlighted. We also go through different clinical conditions and therapeutic approaches that target cardiac iron dyshomeostasis. Finally, we conclude the review by outlining the present knowledge gaps and important open questions in this field in order to guide future research on cardiac iron metabolism.

Interleukin-6 blockade reduces salt-induced cardiac inflammation and fibrosis in subtotal nephrectomized mice

Cardiovascular disease is the most common comorbidity in patients with chronic kidney disease (CKD), affecting both their prognosis and quality of life. Cardiac fibrosis is common in patients with CKD with left ventricular diastolic dysfunction, and it is associated with increased risk of heart failure and mortality. Recent evidence suggests that high salt intake activates immune responses associated with local accumulation of sodium. We reported that high salt intake promotes cardiac inflammation in subtotal nephrectomized (Nx) mice. We investigated the effects of administration of MR16-1, a rat anti-mouse monoclonal interleukin (IL)-6 receptor antibody, in Nx mice with salt loading (Nx-salt). Expression of monocyte chemoattractant protein-1, tumor necrosis factor-α, IL-1β, and IL-6 mRNAs and macrophage infiltration was significantly reduced in the heart of Nx-salt mice treated with MR16-1 (Nx-salt-MR16-1) compared with Nx-salt mice treated with control rat rat IgG1 (Nx-salt-rat IgG1). Correspondingly, cardiac fibrosis was significantly attenuated in Nx-salt-MR16-1 mice compared with Nx-salt-rat IgG1 mice. Furthermore, in the heart of Nx-salt-MR16-1 mice, expression of mRNA for nicotinamide adenine dinucleotide phosphate oxidase-2, an oxidative stress marker, was significantly downregulated compared with Nx-salt-rat IgG1 mice. Increases in cardiac metabolites, including histidine and γ-butyrobetaine, were also reversed by IL-6 blockade treatment. In conclusion, IL-6 blockade exerts anti-inflammatory, antifibrotic, and partial antioxidative effects in the heart of Nx-salt mice.NEW & NOTEWORTHY In the present study, IL-6 blockade exerted anti-inflammatory, antifibrotic, and partial antioxidative effects on the hearts of mice with CKD on a high-salt diet. Therefore, IL-6 potentially mediates cardiac fibrosis induced by high salt intake in patients with CKD, a finding with therapeutic implications. Of note, the next therapeutic implication may simply be the reinforcement of low-salt diets or diuretics and further research on the anti-inflammatory effects of these measures rather than IL-6 blockade with high-salt diet.

METTL3-modified lncRNA-SNHG8 binds to PTBP1 to regulate ALAS2 expression to increase oxidative stress and promote myocardial infarction

Myocardial infarction (MI) is one of the important factors leading to death in today's society. Therefore, to study the related mechanism of MI and reduce myocardial ischemia-reperfusion injury is an important link to reduce MI injury. MI mice in vivo and cell model in vitro were constructed. The cardiac function and MI area of mice were detected, and myocardial tissue injury was detected by HE staining. ALAS2 expression in mice myocardial tissue was detected by IHC. The expressions of lncRNA-SNHG8, METTL3, PTBP1 and ALAS2 in myocardial tissue or cardiomyocytes were detected by qRT-PCR assay. MTT assay was used to measured viability of cardiomyocytes. The oxidative stress level in myocardial tissue or cardiomyocytes was detected by ELISA assay and ROS assay. RIP-qPCR and RNA pulldown assays determined the interaction between METTL3 and lncRNA-SNHG8, as well as PTBP1 and ALAS2. lncRNA-SNHG8 knockdown in MI mice was reduced myocardial infarction size, alleviated myocardial tissue injury and oxidative stress, and inhibited ALAS2 expression in myocardial tissue. RNA pulldown and RIP assays showed that lncRNA-SNHG8 binged with PTBP1 and PTBP1 interacted with ALAS2 mRNA. Knockdown of lncRNA-SNHG8, METTL3 or PTBP1 in MI cells enhanced viability of myocardial cells, attenuated ROS release and MDA level, increased SOD level, alleviated oxidative stress. ALAS overexpression attenuated the corresponding effect of knockdown of lncRNA-SNHG8 and/or PTBP1 on MI cells. In sum, our paper is demonstrated for the first time that METTL3 can promote lncRNA-SNHG8 through m6A modification, thereby regulating ALAS2 to induce oxidative stress and aggravate myocardial injury.

Potential cardiotoxicity induced by Euodiae Fructus: In vivo and in vitro experiments and untargeted metabolomics research

Background: Euodiae Fructus, a well-known herbal medicine, is widely used in Asia and has also gained in popularity in Western countries over the last decades. It has known side effects, which have been observed in clinical settings, but few studies have reported on its cardiotoxicity. Methods: In the present study, experiments using techniques of untargeted metabolomics clarify the hazardous effects of Euodiae Fructus on cardiac function and metabolism in rats in situations of overdosage and unsuitable syndrome differentiation. In vitro assays are conducted to observe the toxic effects of evodiamine and rutaecarpine, two main chemical constituents of Euodiae Fructus, in H9c2 and neonatal rat cardiomyocytes (NRCMs), with their signaling mechanisms analyzed accordingly. Results: The cardiac cytotoxicity of evodiamine and rutaecarpine in in vivo experiments is associated with remarkable alterations in lactate dehydrogenase, creatine kinase, and mitochondrial membrane potential; also with increased intensity of calcium fluorescence, decreased protein expression of the cGMP-PKG pathway in H9c2 cells, and frequency of spontaneous beat in NRCMs. Additionally, the results in rats with Yin deficiency receiving a high-dosage of Euodiae Fructus suggest obvious cardiac physiological dysfunction, abnormal electrocardiogram, pathological injuries, and decreased expression of PKG protein. At the level of endogenous metabolites, the cardiac side effects of overdose and irrational usage of Euodiae Fructus relate to 34 differential metabolites and 10 metabolic pathways involving among others, the purine metabolism, the glycerophospholipid metabolism, the glycerolipid metabolism, and the sphingolipid metabolism. Conclusion: These findings shed new light on the cardiotoxicity induced by Euodiae Fructus, which might be associated with overdose and unsuitable syndrome differentiation, that comes from modulating the cGMP-PKG pathway and disturbing the metabolic pathways of purine, lipid, and amino acid. Continuing research is needed to ensure pharmacovigilance for the safe administration of Chinese herbs in the future.

Exploration of the amino acid metabolic signature in anthracycline-induced cardiotoxicity using an optimized targeted metabolomics approach based on UPLC-MS/MS

Although anthracyclines improve the long-term survival rate of patients with cancer, severe and irreversible myocardial damage limits their clinical application. Amino acid (AA) metabolism in cardiomyocytes can be altered under pathological conditions. Therefore, exploring the AA metabolic signature in anthracycline-induced cardiotoxicity (AIC) is important for identifying novel mechanisms. We established mouse and cellular models of Adriamycin (ADR)-induced cardiac injury. We observed a decreased expression of troponins I (cTnI) after ADR treatment and ADR accelerated the degradation of cTnI, implying that AA metabolism could be altered in AIC. Using a targeted AA metabolomics approach based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), the AA metabolic signatures in the sera of AIC mice and supernatant samples of ADR-treated H9c2 cardiomyocytes were analyzed. The levels of 14 AA metabolites were altered in ADR-treated mice (p < 0.05). Via bioinformatics analysis, we identified nine differential AA metabolites in mice and five differential AA metabolites in ADR-treated H9c2 cardiomyocytes. Three AAs with increased levels (L-glutamate, L-serine, and L-tyrosine) overlapped in the two models, suggesting a possible mechanism of AA metabolic impairment during AIC. The metabolic pathways perturbed by AIC involved aminoacyl-tRNA biosynthesis and alanine, aspartate, and glutamate metabolism. Our data suggests that ADR perturbed AA metabolism in AIC models. Moreover, the targeted AA metabolomics approach based on UPLC-MS/MS can be a unique platform to provide new clues for the prevention and treatment of AIC.

Understanding How Heart Metabolic Derangement Shows Differential Stage Specificity for Heart Failure with Preserved and Reduced Ejection Fraction

Heart failure (HF) is a clinical condition defined by structural and functional abnormalities in the heart that gradually result in reduced cardiac output (HFrEF) and/or increased cardiac pressures at rest and under stress (HFpEF). The presence of asymptomatic individuals hampers HF identification, resulting in delays in recognizing patients until heart dysfunction is manifested, thus increasing the chance of poor prognosis. Given the recent advances in metabolomics, in this review we dissect the main alterations occurring in the metabolic pathways behind the decrease in cardiac function caused by HF. Indeed, relevant preclinical and clinical research has been conducted on the metabolite connections and differences between HFpEF and HFrEF. Despite these promising results, it is crucial to note that, in addition to identifying single markers and reliable threshold levels within the healthy population, the introduction of composite panels would strongly help in the identification of those individuals with an increased HF risk. That said, additional research in the field is required to overcome the current drawbacks and shed light on the pathophysiological changes that lead to HF. Finally, greater collaborative data sharing, as well as standardization of procedures and approaches, would enhance this research field to fulfil its potential.

Citrate Synthase Insufficiency Leads to Specific Metabolic Adaptations in the Heart and Skeletal Muscles Upon Low-Carbohydrate Diet Feeding in Mice

A decrease in TCA cycle activity may lead to impaired nutrition metabolism and cellular energy shortage. Herein, we aimed to characterize the detailed metabolic changes that compensate for energy shortages in energy-consuming organs (heart and skeletal muscles) in mice with knockout of citrate synthase (CS), an important enzyme in the TCA cycle. CS hetero knockout (CS +/−) mice and wild-type mice were fed a low-carbohydrate ketogenic diet (LCKD) or high-fat, high-carbohydrate diet (HFHCD) to induce metabolic changes. Body weight, blood serum parameters, metabolic gene expression, and adenosine triphosphate (ATP) levels were measured in the heart and skeletal muscles. Glycogen content, anabolic and catabolic biomarkers, and morphological changes were also assessed in the skeletal muscles. After diet feeding, there were no differences observed in the body weight and blood serum parameters between wild-type and CS +/− mice. The cardiac expression of genes related to the utilization of fatty acids, monocarboxylates, and branched amino acids increased in LCKD-fed CS +/− mice. In contrast, no significant differences in gene expression were observed in the muscles of LCKD-fed mice or the heart and muscles of HFHCD-fed mice. ATP levels decreased only in the skeletal muscles of LCKD-fed CS +/− mice. Additionally, the decrease in glycogen content, suppression of p70 S6 kinase, and presence of type I fiber atrophy were observed in the muscles of LCKD-fed CS +/− mice. These results suggest that the energy-consuming organs with CS insufficiency may undergo tissue-specific adaption to compensate for energy shortages when the carbohydrate supply is limited.

Integrated Multilayer Omics Reveals the Genomic, Proteomic, and Metabolic Influences of Histidyl Dipeptides on the Heart

Background

Histidyl dipeptides such as carnosine are present in a micromolar to millimolar range in mammalian hearts. These dipeptides facilitate glycolysis by proton buffering. They form conjugates with reactive aldehydes, such as acrolein, and attenuate myocardial ischemia–reperfusion injury. Although these dipeptides exhibit multifunctional properties, a composite understanding of their role in the myocardium is lacking.

Methods and Results

To identify histidyl dipeptide–mediated responses in the heart, we used an integrated triomics approach, which involved genome‐wide RNA sequencing, global proteomics, and unbiased metabolomics to identify the effects of cardiospecific transgenic overexpression of the carnosine synthesizing enzyme, carnosine synthase (Carns), in mice. Our result showed that higher myocardial levels of histidyl dipeptides were associated with extensive changes in the levels of several microRNAs, which target the expression of contractile proteins, β‐fatty acid oxidation, and citric acid cycle (TCA) enzymes. Global proteomic analysis showed enrichment in the expression of contractile proteins, enzymes of β‐fatty acid oxidation, and the TCA in the Carns transgenic heart. Under aerobic conditions, the Carns transgenic hearts had lower levels of short‐ and long‐chain fatty acids as well as the TCA intermediate—succinic acid; whereas, under ischemic conditions, the accumulation of fatty acids and TCA intermediates was significantly attenuated. Integration of multiple data sets suggested that β‐fatty acid oxidation and TCA pathways exhibit correlative changes in the Carns transgenic hearts at all 3 levels.

Conclusions

Taken together, these findings reveal a central role of histidyl dipeptides in coordinated regulation of myocardial structure, function, and energetics.

Ergothioneine: A Stress Vitamin with Antiaging, Vascular, and Neuroprotective Roles?

Significance: Ergothioneine (ET) is an unusual sulfur-containing amino acid derived from histidine, acquired predominantly from food. Its depletion is associated with deleterious consequences in response to stress stimuli in cell culture models, prompting us to classify it as a vitamin in 2010, which was later supported by in vivo studies. ET is obtained from a variety of foods and is taken up by a selective transporter. ET possesses antioxidant and anti-inflammatory properties that confer cytoprotection. ET crosses the blood-brain barrier and has been reported to have beneficial effects in the brain. In this study, we discuss the cytoprotective and neuroprotective properties of ET, which may be harnessed for combating neurodegeneration and decline during aging. Recent Advances: The designation of ET as a stress vitamin is gaining momentum, opening a new field of investigation involving small molecules that are essential for optimal physiological functioning and maintenance of health span. Critical Issues: Although ET was discovered more than a century ago, its physiological functions are still being elucidated, especially in the brain. As ET is present in most foods, toxicity associated with its deprivation has been difficult to assess. Future Directions: Using genetically engineered cells and mice, it may now be possible to elucidate roles of ET. This coupled with advances in genomics and metabolomics may lead to identification of ET function. As ET is a stable antioxidant with anti-inflammatory properties, whose levels decline during aging, supplementing ET in the diet or consuming an ET-rich diet may prove beneficial. Antioxid. Redox Signal. 36, 1306-1317.

Metabolic Signatures of Pregnancy-Induced Cardiac Growth

The goal of this study was to develop an atlas of the metabolic, transcriptional, and proteomic changes that occur with pregnancy in the maternal heart. Timed pregnancy studies in FVB/NJ mice revealed significant increases in heart size by day 8 of pregnancy (mid-pregnancy; MP), which was sustained throughout the rest of the term compared with non-pregnant controls. Cardiac hypertrophy and myocyte cross-sectional area were highest 7 d after birth (post-birth; PB) and were associated with significant increases in end-diastolic and end-systolic left ventricular volumes and cardiac output. Metabolomics analyses revealed that, by day 16 of pregnancy (late pregnancy; LP), metabolites associated with nitric oxide production as well as acylcholines, sphingomyelins, and fatty acid species were elevated, which coincided with a lower activation state of phosphofructokinase and higher levels of pyruvate dehydrogenase kinase 4 (Pdk4). In the postpartum period, urea cycle metabolites, polyamines, and phospholipid levels were markedly elevated in the maternal heart. Cardiac transcriptomics in LP revealed significant increases in not only Pdk4, but also genes that regulate glutamate and ketone body oxidation, which were preceded in MP by higher expression of transcripts controlling cell proliferation and angiogenesis. Proteomics analysis of the maternal heart in LP and PB revealed significant reductions in several contractile filaments and mitochondrial complex subunits. Collectively, these findings describe the coordinated molecular changes that occur in the maternal heart during and after pregnancy.

KATP channel dependent heart multiome atlas

Plasmalemmal ATP sensitive potassium (K_ATP) channels are recognized metabolic sensors, yet their cellular reach is less well understood. Here, transgenic Kir6.2 null hearts devoid of the K_ATP channel pore underwent multiomics surveillance and systems interrogation versus wildtype counterparts. Despite maintained organ performance, the knockout proteome deviated beyond a discrete loss of constitutive K_ATP channel subunits. Multidimensional nano-flow liquid chromatography tandem mass spectrometry resolved 111 differentially expressed proteins and their expanded network neighborhood, dominated by metabolic process engagement. Independent multimodal chemometric gas and liquid chromatography mass spectrometry unveiled differential expression of over one quarter of measured metabolites discriminating the Kir6.2 deficient heart metabolome. Supervised class analogy ranking and unsupervised enrichment analysis prioritized nicotinamide adenine dinucleotide (NAD⁺), affirmed by extensive overrepresentation of NAD⁺ associated circuitry. The remodeled metabolome and proteome revealed functional convergence and an integrated signature of disease susceptibility. Deciphered cardiac patterns were traceable in the corresponding plasma metabolome, with tissue concordant plasma changes offering surrogate metabolite markers of myocardial latent vulnerability. Thus, Kir6.2 deficit precipitates multiome reorganization, mapping a comprehensive atlas of the K_ATP channel dependent landscape.

Comprehending Cardiac Dysfunction by Oxidative Stress: Untargeted Metabolomics of In Vitro Samples

Cardiovascular diseases (CVDs) are noncommunicable diseases known for their complex etiology and high mortality rate. Oxidative stress (OS), a condition in which the release of free radical exceeds endogenous antioxidant capacity, is pivotal in CVC, such as myocardial infarction, ischemia/reperfusion, and heart failure. Due to the lack of information about the implications of OS on cardiovascular conditions, several methodologies have been applied to investigate the causes and consequences, and to find new ways of diagnosis and treatment as well. In the present study, cardiac dysfunction was evaluated by analyzing cells’ alterations with untargeted metabolomics, after simulation of an oxidative stress condition using hydrogen peroxide (H₂O₂) in H9c2 myocytes. Optimizations of H₂O₂ concentration, cell exposure, and cell recovery times were performed through MTT assays. Intracellular metabolites were analyzed right after the oxidative stress (oxidative stress group) and after 48 h of cell recovery (recovery group) by ultra-high-performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) in positive and negative ESI ionization mode. Significant alterations were found in pathways such as “alanine, aspartate and glutamate metabolism”, “glycolysis”, and “glutathione metabolism”, mostly with increased metabolites (upregulated). Furthermore, our results indicated that the LC-MS method is effective for studying metabolism in cardiomyocytes and generated excellent fit (R²Y > 0.987) and predictability (Q² > 0.84) values.

Nuclear Tkt promotes ischemic heart failure via the cleaved Parp1/Aif axis

Transketolase (Tkt), an enzyme in pentose phosphate pathway, has been reported to regulate genome instability and cell survival in cancers. Yet, the role of Tkt after myocardial ischemic injury remains to be elucidated. Label-free proteomics revealed dramatic elevation of Tkt in murine hearts after myocardial infarction (MI). Lentivirus-mediated Tkt knockdown ameliorated cardiomyocyte apoptosis and preserved the systolic function after myocardial ischemic injury. In contrast, Tkt overexpression led to the opposite effects. Inducible conditional cardiomyocyte Tkt-knockout mice were generated, and cardiomyocyte-expressed Tkt was found to play an intrinsic role in the ischemic heart failure of these model mice. Furthermore, through luciferase assay and chromatin immunoprecipitation, Tkt was shown to be a direct target of transcription factor Krüppel-like factor 5 (Klf5). In cardiomyocytes under ischemic stress, Tkt redistributed into the nucleus. By binding with the full-length poly(ADP-ribose) polymerase 1 (Parp1), facilitating its cleavage, and activating apoptosis inducible factor (Aif) subsequently, nuclear Tkt demonstrated its non-metabolic functions. Overall, our study confirmed that elevated nuclear Tkt plays a noncanonical role in promoting cardiomyocyte apoptosis via the cleaved Parp1/Aif pathway, leading to the deterioration of cardiac dysfunction.

Beta-blocker/ACE inhibitor therapy differentially impacts the steady state signaling landscape of failing and non-failing hearts

Heart failure is a multifactorial disease that affects an estimated 38 million people worldwide. Current pharmacotherapy of heart failure with reduced ejection fraction (HFrEF) includes combination therapy with angiotensin-converting enzyme inhibitors (ACEi) and β-adrenergic receptor blockers (β-AR blockers), a therapy also used as treatment for non-cardiac conditions. Our knowledge of the molecular changes accompanying treatment with ACEi and β-AR blockers is limited. Here, we applied proteomics and phosphoproteomics approaches to profile the global changes in protein abundance and phosphorylation state in cardiac left ventricles consequent to combination therapy of β-AR blocker and ACE inhibitor in HFrEF and control hearts. The phosphorylation changes induced by treatment were profoundly different for failing than for non-failing hearts. HFrEF was characterized by profound downregulation of mitochondrial proteins coupled with derangement of β-adrenergic and pyruvate dehydrogenase signaling. Upon treatment, phosphorylation changes consequent to HFrEF were reversed. In control hearts, treatment mainly led to downregulation of canonical PKA signaling. The observation of divergent signaling outcomes depending on disease state underscores the importance of evaluating drug effects within the context of the specific conditions present in the recipient heart.

Heart Failure and Drug Therapies: A Metabolic Review

Cardiovascular disease is the leading cause of mortality globally with at least 26 million people worldwide living with heart failure (HF). Metabolism has been an active area of investigation in the setting of HF since the heart demands a high rate of ATP turnover to maintain homeostasis. With the advent of -omic technologies, specifically metabolomics and lipidomics, HF pathologies have been better characterized with unbiased and holistic approaches. These techniques have identified novel pathways in our understanding of progression of HF and potential points of intervention. Furthermore, sodium-glucose transport protein 2 inhibitors, a drug that has changed the dogma of HF treatment, has one of the strongest types of evidence for a potential metabolic mechanism of action. This review will highlight cardiac metabolism in both the healthy and failing heart and then discuss the metabolic effects of heart failure drugs.

Metabolomic and transcriptomic signatures of chemogenetic heart failure

The failing heart is characterized by elevated levels of reactive oxygen species. We have developed an animal model of heart failure induced by chemogenetic production of oxidative stress in the heart using a recombinant adeno-associated virus (AAV9) expressing yeast d-amino acid oxidase (DAAO) targeted to cardiac myocytes. When DAAO-infected animals are fed the DAAO substrate d-alanine, the enzyme generates hydrogen peroxide (H₂O₂) in the cardiac myocytes, leading to dilated cardiomyopathy. However, the underlying mechanisms of oxidative stress-induced heart failure remain incompletely understood. Therefore, we investigated the effects of chronic oxidative stress on the cardiac transcriptome and metabolome. Rats infected with recombinant cardiotropic AAV9 expressing DAAO or control AAV9 were treated for 7 wk with d-alanine to stimulate chemogenetic H₂O₂ production by DAAO and generate dilated cardiomyopathy. After hemodynamic assessment, left and right ventricular tissues were processed for RNA sequencing and metabolomic profiling. DAAO-induced dilated cardiomyopathy was characterized by marked changes in the cardiac transcriptome and metabolome both in the left and right ventricle. Downregulated transcripts are related to energy metabolism and mitochondrial function, accompanied by striking alterations in metabolites involved in cardiac energetics, redox homeostasis, and amino acid metabolism. Upregulated transcripts are involved in cytoskeletal organization and extracellular matrix. Finally, we noted increased metabolite levels of antioxidants glutathione and ascorbate. These findings provide evidence that chemogenetic generation of oxidative stress leads to a robust heart failure model with distinct transcriptomic and metabolomic signatures and set the basis for understanding the underlying pathophysiology of chronic oxidative stress in the heart.NEW & NOTEWORTHY We have developed a "chemogenetic" heart failure animal model that recapitulates a central feature of human heart failure: increased cardiac redox stress. We used a recombinant DAAO enzyme to generate H₂O₂ in cardiomyocytes, leading to cardiomyopathy. Here we report striking changes in the cardiac metabolome and transcriptome following chemogenetic heart failure, similar to changes observed in human heart failure. Our findings help validate chemogenetic approaches for the discovery of novel therapeutic targets in heart failure.

Metabolic Reprogramming, Gut Dysbiosis, and Nutrition Intervention in Canine Heart Disease

This review provides a state-of-the-art overview on recent advances in systems biology in canine cardiac disease, with a focus on our current understanding of bioenergetics and amino acid metabolism in myxomatous mitral valve disease (MMVD). Cross-species comparison is drawn to highlight the similarities between human and canine heart diseases. The adult mammalian heart exhibits a remarkable metabolic flexibility and shifts its energy substrate preference according to different physiological and pathological conditions. The failing heart suffers up to 40% ATP deficit and is compared to an engine running out of fuel. Bioenergetics and metabolic readaptations are among the major research topics in cardiac research today. Myocardial energy metabolism consists of three interconnected components: substrate utilization, oxidative phosphorylation, and ATP transport and utilization. Any disruption or uncoupling of these processes can result in deranged energy metabolism leading to heart failure (HF). The review describes the changes occurring in each of the three components of energy metabolism in MMVD and HF. It also provides an overview on the changes in circulating and myocardial glutathione, taurine, carnitines, branched-chain amino acid catabolism and tryptophan metabolic pathways. In addition, the review summarizes the potential role of the gut microbiome in MMVD and HF. As our knowledge and understanding in these molecular and metabolic processes increase, it becomes possible to use nutrition to address these changes and to slow the progression of the common heart diseases in dogs.

Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Non-targeted metabolomics identify polyamine metabolite acisoga as novel biomarker for reduced left ventricular function

AIMS

Chronic heart failure with reduced ejection fraction remains a major health issue. To date, no reliable biomarker is available to predict reduced left ventricular ejection fraction (LV-EF). We aimed to identify novel circulating biomarkers for reduced left ventricular function using untargeted serum metabolomics in two independent patient cohorts.

METHODS AND RESULTS

Echocardiography and non-targeted serum metabolomics were conducted in two patient cohorts with varying left ventricular function: (1) 25 patients with type 2 diabetes with established cardiovascular disease or high cardiovascular risk (LV-EF range 20-66%) (discovery cohort) and (2) 37 patients hospitalized for myocardial infarction (LV-EF range 25-60%) (validation cohort). In the discovery cohort, untargeted metabolomics revealed seven metabolites performing better than N-terminal pro-B-type natriuretic peptide in the prediction of impaired left ventricular function shown by LV-EF. For only one of the metabolites, acisoga, the predictive value for LV-EF could be confirmed in the validation cohort (r = -0.37, P = 0.02). In the discovery cohort, acisoga did not only correlate with LV-EF (r = -60, P = 0.0016), but also with global circumferential strain (r = 0.67, P = 0.0003) and global longitudinal strain (r = 0.68, P = 0.0002). Similar results could be detected in the discovery cohort in a 6 month follow-up proofing stability of these results over time. With an area under the curve of 0.86 in the receiver operating characteristic analysis, acisoga discriminated between patients with normal EF and LV-EF < 40%. Multivariate analysis exposed acisoga as independent marker for impairment of LV-EF (Beta = -0.71, P = 0.004).

CONCLUSIONS

We found the polyamine metabolite acisoga to be elevated in patients with impaired LV-EF in two independent cohorts. Our analyses suggest that acisoga may be a valuable biomarker to detect patients with heart failure with reduced ejection fraction.