Metabolism, Epigenetics, and Causal Inference in Heart Failure

Sacubitril/valsartan ameliorates cardiac function and ventricular remodeling in CHF rats via the inhibition of the tryptophan/kynurenine metabolism and inflammation

Sacubitril/valsartan has been highly recognized as a treatment for Chronic heart failure (CHF). Its potential cardioprotective benefits and mechanisms, however, remain to be explored. Metabolomics can be used to identify the metabolic characteristics and related markers, as well as the influence of drugs, thereby opening up the new mechanism for sacubitril/valsartan therapy in CHF disease. In this study, the ligation of left anterior descending and exhaustive swimming were used to induce a rat model of CHF after myocardial infarction. The efficacy was appraised with echocardiography, serum NT-proBNP, and histopathologica. UPLC-Q/TOF-MS combined with multivariate statistical analysis approach were used to analyze the effect of sacubitril/valsartan on CHF rats. RT-qPCR and western blot were performed to investigate the tryptophan/kynurenine metabolism pathway. Accordingly, the basal cardiac function were increased, while the serum NT-proBNP and collagen volume fraction decreased in CHF rats with sacubitril/valsartan. Sacubitril/valsartan regulated the expression of kynurenine et.al 8 metabolomic biomarkers in CHF rats serum, and it contributed to the cardioprotective effects through tryptophan metabolism pathway. In addition, the mRNA and protein expression of the indoleamine 2,3-dioxygenase (IDO) in the myocardial tissue of CHF rats, were down-regulated by sacubitril/valsartan, which was the same with the IL-1β, IFN-γ, TNF-α, COX-2, and IL-6 mRNA expression, and IL-1β, IFN-γ, and TNF-α expression in serum. In conclusion, sacubitril/valsartan can ameliorate cardiac function and ventricular remodeling in CHF rats, at least in part through inhibition of tryptophan/kynurenine metabolism.

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.

Reverse cardio-oncology: A budding concept

Having established the significance of cardiovascular side-effects of anti-neoplastic drugs, present day cardio-oncology has forayed into newer territories buoyed by research into the multiple connections that exist between cardiovascular disease and cancer. An emerging concept of reverse cardio-oncology focuses on the heightened risk of cancer in patients with cardiovascular disease. Common mechanistics of cancer and heart failure (HF) like chronic inflammation and clonal haematopoesis as well as common predisposing factors like obesity and diabetes underline the relation between both cardiovascular disease and various cancers.This review discusses the potential magnitude of the problem, the underlying pathophysiological mechanisms and classification of this novel subject.

Comparative Metabolomics in Single Ventricle Patients after Fontan Palliation: A Strong Case for a Targeted Metabolic Therapy

Most studies on single ventricle (SV) circulation take a physiological or anatomical approach. Although there is a tight coupling between cardiac contractility and metabolism, the metabolic perspective on this patient population is very recent. Early findings point to major metabolic disturbances, with both impaired glucose and fatty acid oxidation in the cardiomyocytes. Additionally, Fontan patients have systemic metabolic derangements such as abnormal glucose metabolism and hypocholesterolemia. Our literature review compares the metabolism of patients with a SV circulation after Fontan palliation with that of patients with a healthy biventricular (BV) heart, or different subtypes of a failing BV heart, by Pubmed review of the literature on cardiac metabolism, Fontan failure, heart failure (HF), ketosis, metabolism published in English from 1939 to 2023. Early evidence demonstrates that SV circulation is not only a hemodynamic burden requiring staged palliation, but also a metabolic issue with alterations similar to what is known for HF in a BV circulation. Alterations of fatty acid and glucose oxidation were found, resulting in metabolic instability and impaired energy production. As reported for patients with BV HF, stimulating ketone oxidation may be an effective treatment strategy for HF in these patients. Few but promising clinical trials have been conducted thus far to evaluate therapeutic ketosis with HF using a variety of instruments, including ketogenic diet, ketone esters, and sodium-glucose co-transporter-2 (SGLT2) inhibitors. An initial trial on a small cohort demonstrated favorable outcomes for Fontan patients treated with SGLT2 inhibitors. Therapeutic ketosis is worth considering in the treatment of Fontan patients, as ketones positively affect not only the myocardial energy metabolism, but also the global Fontan physiopathology. Induced ketosis seems promising as a concerted therapeutic strategy.

Nuclear ATR lysine-tyrosylation protects against heart failure by activating DNA damage response

Dysregulated amino acid increases the risk for heart failure (HF) via unclear mechanisms. Here, we find that increased plasma tyrosine and phenylalanine levels are associated with HF. Increasing tyrosine or phenylalanine by high-tyrosine or high-phenylalanine chow feeding exacerbates HF phenotypes in transverse aortic constriction and isoproterenol infusion mice models. Knocking down phenylalanine dehydrogenase abolishes the effect of phenylalanine, indicating that phenylalanine functions by converting to tyrosine. Mechanistically, tyrosyl-tRNA synthetase (YARS) binds to ataxia telangiectasia and Rad3-related gene (ATR), catalyzes lysine tyrosylation (K-Tyr) of ATR, and activates the DNA damage response (DDR) in the nucleus. Increased tyrosine inhibits the nuclear localization of YARS, inhibits the ATR-mediated DDR, accumulates DNA damage, and elevates cardiomyocyte apoptosis. Enhancing ATR K-Tyr by overexpressing YARS, restricting tyrosine, or supplementing tyrosinol, a structural analog of tyrosine, promotes YARS nuclear localization and alleviates HF in mice. Our findings implicate facilitating YARS nuclear translocation as a potential preventive and/or interfering measure against HF.

The Current Therapeutic Role of Chromatin Remodeling for the Prognosis and Treatment of Heart Failure

Cardiovascular diseases are a major cause of death globally, with no cure to date. Many interventions have been studied and suggested, of which epigenetics and chromatin remodeling have been the most promising. Over the last decade, major advancements have been made in the field of chromatin remodeling, particularly for the treatment of heart failure, because of innovations in bioinformatics and gene therapy. Specifically, understanding changes to the chromatin architecture have been shown to alter cardiac disease progression via variations in genomic sequencing, targeting cardiac genes, using RNA molecules, and utilizing chromatin remodeler complexes. By understanding these chromatin remodeling mechanisms in an injured heart, treatments for heart failure have been suggested through individualized pharmaceutical interventions as well as biomarkers for major disease states. By understanding the current roles of chromatin remodeling in heart failure, a potential therapeutic approach may be discovered in the future.

Mitochondria-associated endoplasmic reticulum membranes (MAMs): Possible therapeutic targets in heart failure

Mitochondria-associated endoplasmic reticulum membranes (MAMs) are formed by physical connections of the endoplasmic reticulum and mitochondria. Over the past decades, great breakthroughs have been made in the study of ER-mitochondria communications. It has been identified that MAM compartments are pivotal in regulating neurological function. Accumulating studies indicated that MAMs participate in the development of cardiovascular diseases. However, the specific role of MAMs in heart failure remains to be fully understood. In this article, we first summarize the structural and functional properties of MAM and MAM-associated proteins. We then focus on the roles of MAMs in myocardial infarction, cardiomyopathy and heart failure, and discuss the involvement of MAMs in disease progression and treatment. Elucidating these issues may provide important insights into therapeutic intervention of heart failure.

Metabolic remodeling in takotsubo syndrome

The heart requires a large and constant supply of energy that is mainly the result of an efficient metabolic machinery that converges on mitochondrial oxidative metabolism to maintain its continuous mechanical work. Perturbations in these metabolic processes may therefore affect energy generation and contractile function directly. Metabolism characteristics in takotsubo syndrome (TTS) reveals several metabolic alterations called metabolic remodeling, including the hyperactivity of sympathetic metabolism, derangements of substrate utilization, effector subcellular dysfunction and systemic metabolic disorders, ultimately contributing to the progression of the disease and the development of a persistent and long-term heart failure (HF) phenotype. In this review, we explore the current literature investigating the pathological metabolic alterations in TTS. Although the metabolic dysfunction in takotsubo hearts is initially recognized as a myocardial metabolic inflexibility, we suggest that the widespread alterations of systemic metabolism with complex interplay between the heart and peripheral tissues rather than just cardiometabolic disorders per se account for long-term maladaptive metabolic, functional and structural impairment under this condition. Therapeutic strategies with the recent evidence from small clinical and animal researches, especially for targeting substrate utilization and/or oxidative stress, might be promising tools to improve the outcome of patients with TTS beyond that achieved with traditional sympathetic inhibition and symptomatic therapies.

Cardiac fibroblasts and mechanosensation in heart development, health and disease

The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart.

Cardio-Oncology: Mechanisms, Drug Combinations, and Reverse Cardio-Oncology

Chemotherapy, radiotherapy, targeted therapy, and immunotherapy have brought hope to cancer patients. With the prolongation of survival of cancer patients and increased clinical experience, cancer-therapy-induced cardiovascular toxicity has attracted attention. The adverse effects of cancer therapy that can lead to life-threatening or induce long-term morbidity require rational approaches to prevention and treatment, which requires deeper understanding of the molecular biology underpinning the disease. In addition to the drugs used widely for cardio-protection, traditional Chinese medicine (TCM) formulations are also efficacious and can be expected to achieve “personalized treatment” from multiple perspectives. Moreover, the increased prevalence of cancer in patients with cardiovascular disease has spurred the development of “reverse cardio-oncology”, which underscores the urgency of collaboration between cardiologists and oncologists. This review summarizes the mechanisms by which cancer therapy induces cardiovascular toxicity, the combination of antineoplastic and cardioprotective drugs, and recent advances in reverse cardio-oncology.

DNMT3B System Dysregulation Contributes to the Hypomethylated State in Ischaemic Human Hearts

A controversial understanding of the state of the DNA methylation machinery exists in ischaemic cardiomyopathy (ICM). Moreover, its relationship to other epigenetic alterations is incomplete. Therefore, we carried out an in-depth study of the DNA methylation process in human cardiac tissue. We showed a dysregulation of the DNA methylation machinery accordingly with the genome-wide hypomethylation that we observed: specifically, an overexpression of main genes involved in the elimination of methyl groups (TET1, SMUG1), and underexpression of molecules implicated in the maintenance of methylation (MBD2, UHRF1). By contrast, we found DNMT3B upregulation, a key molecule in the addition of methyl residues in DNA, and an underexpression of miR-133a-3p, an inhibitor of DNMT3B transcription. However, we found many relevant alterations that would counteract the upregulation observed, such as the overexpression of TRAF6, responsible for Dnmt3b degradation. Furthermore, we showed that molecules regulating Dnmts activity were altered; specifically, SAM/SAH ratio reduction. All these results are in concordance with the Dnmts normal function that we show. Our analysis revealed genome-wide hypomethylation along with dysregulation in the mechanisms of addition, elimination and maintenance of methyl groups in the DNA of ICM. We describe relevant alterations in the DNMT3B system, which promote a normal Dnmt3b function despite its upregulation.

The crystallin alpha B (HSPB5)-tripartite motif containing 33 (TRIM33) axis mediates myocardial fibrosis induced by angiotensinogen II through transforming growth factor-β (TGF-β1)-Smad3/4 signaling

Myocardial fibrosis, a common pathological manifestation of cardiac remodeling (CR), often leads to heart failure (HF) and even death. The underlying molecular mechanism of the role of TRIM33 in Ang II–induced myocardial fibrosis is not fully understood. We found that TRIM33 was specifically upregulated in CFs and myocardial tissue after Ang II stimulation. Adult mice induced by Ang II were used as in vivo models, and Ang II–induced neonatal mouse primary cardiac fibroblasts (CFs) were used as in vitro models. The level of CF fibrosis in vitro was assessed by CF proliferation, migration, activation and extracellular matrix (ECM) synthesis. In addition, Masson staining, the heart weight/body weight (HW/BW) ratio and echocardiography were used to evaluate the in vivo effect of TRIM33. TRIM33 expression was specifically upregulated in CFs and myocardial tissue after Ang II stimulation. In in vitro experiments, we found that TRIM33 knockdown promoted Ang II–induced CF proliferation, while TRIM33 overexpression weakened Ang II–induced CF proliferation, migration, activation and collagen synthesis. Mechanistically, we showed that TRIM33, negatively regulated by HSPB5, mediated its antifibrotic effect by inhibiting the activation of TGF-β1 and its downstream genes, Smad3 and Smad4. Finally, TRIM33 overexpression suppressed fibrosis and promoted cardiac repair and functional recovery in Ang II–induced mice. Our results clearly establish that TRIM33 limits cardiac fibrosis by hindering CF proliferation, migration, activation and collagen synthesis. Enhancing these beneficial functions of TRIM33 by a targeting vector might be a novel therapeutic strategy for CR.

Cardiac contractility modulation ameliorates myocardial metabolic remodeling in a rabbit model of chronic heart failure through activation of AMPK and PPAR-α pathway

Metabolic remodeling contributes to the pathological process of heart failure (HF). We explored the effects of cardiac contractility modulation (CCM) on myocardial metabolic remodeling in the rabbit model with HF. The HF in rabbit model was established by pressure uploading and then CCM was applied. We evaluated the cardiac structure and function by echocardiography, serum BNP level, and hematoxylin and eosin and Masson’s trichrome staining. We detected the accumulation of glycogen and lipid droplets in myocardial tissues by periodic acid-Schiff and Oil Red O staining. Then, we measured the contents of glucose, free fatty acid (FFA), lactic acid, pyruvate, and adenosine triphosphate (ATP) levels in myocardial tissues by corresponding kits and the expression levels of key factors related to myocardial substrate uptake and utilization by western blotting were analyzed. CCM significantly restored the cardiac structure and function in the rabbit model with HF. CCM therapy further decreased the accumulation of glycogen and lipid droplets. Furthermore, CCM reduced the contents of FFA, glucose, and lactic acid, and increased pyruvate and ATP levels in HF tissues. The protein expression levels related to myocardial substrate uptake and utilization were markedly improved with CCM treatment by further activating adenosine monophosphate-activated protein kinase and peroxisome proliferator-activated receptor-α signaling pathways.

Light Emitting Diodes Photobiomodulation Improves Cardiac Function by Promoting ATP Synthesis in Mice With Heart Failure

Heart failure (HF) is the common consequences of various cardiovascular diseases, often leading to severe cardiac output deficits with a high morbidity and mortality. In recent years, light emitting diodes-based therapy (LEDT) has been widely used in multiple cardiac diseases, while its modulatory effects on cardiac function with HF still remain unclear. Therefore, the objective of this study was to investigate the effects of LED-Red irradiation on cardiac function in mice with HF and to reveal its mechanisms. In this study, we constructed a mouse model of HF. We found that LED-Red (630 nm) was an effective wavelength for the treatment of HF. Meanwhile, the application of LED-Red therapy to treat HF mice improved cardiac function, ameliorate heart morphology, reduced pulmonary edema, as well as inhibited collagen deposition. Moreover, LED-Red therapy attenuated the extent of perivascular fibrosis. Besides, LED-Red irradiation promoted calcium transients in cardiomyocytes as well as upregulated ATP synthesis, which may have positive implications for contractile function in mice with HF. Collectively, we identified that LED-Red exerts beneficial effects on cardiac function in HF mice possibly by promoting the synthesis of ATP.

NAP1L5 Promotes Nucleolar Hypertrophy and Is Required for Translation Activation During Cardiomyocyte Hypertrophy

Pathological growth of cardiomyocytes during hypertrophy is characterized by excess protein synthesis; however, the regulatory mechanism remains largely unknown. Using a neonatal rat ventricular myocytes (NRVMs) model, here we find that the expression of nucleosome assembly protein 1 like 5 (Nap1l5) is upregulated in phenylephrine (PE)-induced hypertrophy. Knockdown of Nap1l5 expression by siRNA significantly blocks cell size enlargement and pathological gene induction after PE treatment. In contrast, Adenovirus-mediated Nap1l5 overexpression significantly aggravates the pro-hypertrophic effects of PE on NRVMs. RNA-seq analysis reveals that Nap1l5 knockdown reverses the pro-hypertrophic transcriptome reprogramming after PE treatment. Whereas, immune response is dominantly enriched in the upregulated genes, oxidative phosphorylation, cardiac muscle contraction and ribosome-related pathways are remarkably enriched in the down-regulated genes. Although Nap1l5-mediated gene regulation is correlated with PRC2 and PRC1, Nap1l5 does not directly alter the levels of global histone methylations at K4, K9, K27 or K36. However, puromycin incorporation assay shows that Nap1l5 is both necessary and sufficient to promote protein synthesis in cardiomyocyte hypertrophy. This is attributable to a direct regulation of nucleolus hypertrophy and subsequent ribosome assembly. Our findings demonstrate a previously unrecognized role of Nap1l5 in translation control during cardiac hypertrophy.

Endoplasmic Reticulum-Mitochondria Contacts: A Potential Therapy Target for Cardiovascular Remodeling-Associated Diseases

Cardiovascular remodeling occurs in cardiomyocytes, collagen meshes, and vascular beds in the progress of cardiac insufficiency caused by a variety of cardiac diseases such as chronic ischemic heart disease, chronic overload heart disease, myocarditis, and myocardial infarction. The morphological changes that occur as a result of remodeling are the critical pathological basis for the occurrence and development of serious diseases and also determine morbidity and mortality. Therefore, the inhibition of remodeling is an important approach to prevent and treat heart failure and other related diseases. The endoplasmic reticulum (ER) and mitochondria are tightly linked by ER-mitochondria contacts (ERMCs). ERMCs play a vital role in different signaling pathways and provide a satisfactory structural platform for the ER and mitochondria to interact and maintain the normal function of cells, mainly by involving various cellular life processes such as lipid metabolism, calcium homeostasis, mitochondrial function, ER stress, and autophagy. Studies have shown that abnormal ERMCs may promote the occurrence and development of remodeling and participate in the formation of a variety of cardiovascular remodeling-associated diseases. This review focuses on the structure and function of the ERMCs, and the potential mechanism of ERMCs involved in cardiovascular remodeling, indicating that ERMCs may be a potential target for new therapeutic strategies against cardiovascular remodeling-induced diseases.

Function of histone methylation and acetylation modifiers in cardiac hypertrophy

Cardiac hypertrophy is an adaptive response of the heart to increased workload induced by various physiological or pathological stimuli. It is a common pathological process in multiple cardiovascular diseases, and it ultimately leads to heart failure. The development of cardiac hypertrophy is accompanied by gene expression reprogramming, a process that is largely dependent on epigenetic regulation. Histone modifications such as methylation and acetylation are dynamically regulated under cardiac stress. These consequently contribute to the pathogenesis of cardiac hypertrophy via compensatory or maladaptive transcriptome reprogramming. Histone methylation and acetylation modifiers play crucial roles in epigenetic remodeling during the pathogenesis of cardiac hypertrophy. Regulation of histone methylation and acetylation modifiers serves as a bridge between signal transduction and downstream gene reprogramming. Exploring the role of histone modifiers in cardiac hypertrophy provides novel therapeutic strategies to treat cardiac hypertrophy and heart failure. In this review, we summarize the recent advancements in functional histone methylation and acetylation modifiers in cardiac hypertrophy, with an emphasis on the underlying mechanisms and the therapeutic potential.

The remodel of the "central dogma": a metabolomics interaction perspective

BACKGROUND

In 1957, Francis Crick drew a linear diagram on a blackboard. This diagram is often called the "central dogma." Subsequently, the relationships between different steps of the "central dogma" have been shown to be considerably complex, mostly because of the emerging world of small molecules. It is noteworthy that metabolites can be generated from the diet through gut microbiome metabolism, serve as substrates for epigenetic modifications, destabilize DNA quadruplexes, and follow Lamarckian inheritance. Small molecules were once considered the missing link in the "central dogma"; however, recently they have acquired a central role, and their general perception as downstream products has become reductionist. Metabolomics is a large-scale analysis of metabolites, and this emerging field has been shown to be the closest omics associated with the phenotype and concomitantly, the basis for all omics.

AIM OF REVIEW

Herein, we propose a broad updated perspective for the flux of information diagram centered in metabolomics, including the influence of other factors, such as epigenomics, diet, nutrition, and the gut- microbiome.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Metabolites are the beginning and the end of the flux of information.

Epigenetic Mechanisms Involved in the Cardiovascular Toxicity of Anticancer Drugs

The cardiovascular toxicity of anticancer drugs promotes the development of cardiovascular diseases. Therefore, cardiovascular toxicity is an important safety issue that must be considered when developing medications and therapeutic applications to treat cancer. Among anticancer drugs, members of the anthracycline family, such as doxorubicin, daunorubicin and mitoxantrone, are known to cause cardiotoxicity and even heart failure. Using human-induced pluripotent stem cell-derived cardiomyocytes in combination with "Omic" technologies, we identified several cardiotoxicity mechanisms and signal transduction pathways. Moreover, these drugs acted as cardiovascular toxicants through a syndrome of mechanisms, including epigenetic ones. Herein, we discuss the main cardiovascular toxicity mechanisms, with an emphasis on those associated with reactive oxygen species and mitochondria that contribute to cardiotoxic epigenetic modifications. We also discuss how to mitigate the cardiotoxic effects of anticancer drugs using available pharmaceutical "weapons."

Real-time exercise reduces impaired cardiac function in breast cancer patients undergoing chemotherapy: a randomized controlled trial

BACKGROUND

Previous studies have reported that chemotherapy results in substantial long-term risk of heart failure. Exercise ameliorates exercise responses and exercise tolerance in patients receiving chemotherapy. The cardioprotective effect of real-time exercise in breast cancer is still unclear.

OBJECTIVES

The aim of the present study was to determine the effect of real-time moderate-to-high-intensity exercise training in women with breast cancer undergoing chemotherapy and to follow up on parameters of cardiac function and exercise capacity at different times. We hypothesized that early moderate-to-high-intensity exercise training has beneficial effects on cardiac function in women with breast cancer undergoing chemotherapy.

METHODS

This was a randomized controlled study that included 32 women randomly allocated into the control or exercise group. Exercise began with the first cycle of chemotherapy, and the training program was maintained during chemotherapy with 2 to 3 sessions per week for 3 months. Patients were instructed to perform moderate-to-high-intensity training with aerobic and resistance training. Outcome measurements were echocardiography and cardiopulmonary exercise test. The primary outcome was the change in left ventricle ejection fraction (LVEF). The secondary outcome was peak oxygen consumption (peak VO₂).

RESULTS

The control group showed lower cardiac systolic function than the exercise group [mean (SD) LVEF 62% (2) and 70% (5), p < 0.05], reduced cardiac diastolic function, and cardiac hypertrophy at 3, 6 and 12 months after chemotherapy. At 6 months after chemotherapy, the exercise group exhibited relatively higher exercise capacity than controls [mean (SD) VO₂ 12.1 (2.2) and 13.6 (2.2) mL/kg/min, p < 0.05]. The main effect size of the study based on echocardiography outcomes was 0.25 (95% confidence interval 0.23 to 0.27), a medium effect size.

CONCLUSIONS

Moderate-to-high-intensity exercise training in breast cancer patients undergoing chemotherapy may prevent impaired cardiac function.

Irisin: linking metabolism with heart failure

The heart is an organ with extremely high energy expenditure, and cardiac performance is consistent with its metabolic level. Under pathological situations, the heart adjusts its metabolic pattern through mitochondrial regulation and substrate selection to maintain energy homeostasis. Heart failure is associated with impaired cardiac energy production, transduction or utilization. Reduced exercise tolerance, skeletal muscle dystrophy and even cardiac cachexia are commonly found in patients with advanced heart failure. Irisin is a newly identified myokine and is mainly secreted by skeletal muscles after exercise. Irisin regulates metabolism and plays essential roles in the development of metabolic diseases. The heart is another abundant source of irisin synthesis and secretion other than skeletal muscle. However, the functions of irisin in the heart have not been completely elucidated. This review introduces the current understanding of the physiological role of irisin, alteration of irisin levels in heart failure, possible mechanisms of irisin in metabolic remodeling and cardiac hypertrophy, and perspectives of irisin serving as a novel target in the management of heart failure.

Mitochondrial Ca2+ regulation in the etiology of heart failure: physiological and pathophysiological implications

Heart failure (HF) represents one of the leading causes of cardiovascular diseases with high rates of hospitalization, morbidity and mortality worldwide. Ample evidence has consolidated a crucial role for mitochondrial injury in the progression of HF. It is well established that mitochondrial Ca²⁺ participates in the regulation of a wide variety of biological processes, including oxidative phosphorylation, ATP synthesis, reactive oxygen species (ROS) generation, mitochondrial dynamics and mitophagy. Nonetheless, mitochondrial Ca²⁺ overload stimulates mitochondrial permeability transition pore (mPTP) opening and mitochondrial swelling, resulting in mitochondrial injury, apoptosis, cardiac remodeling, and ultimately development of HF. Moreover, mitochondria possess a series of Ca²⁺ transport influx and efflux channels, to buffer Ca²⁺ in the cytoplasm. Interaction at mitochondria-associated endoplasmic reticulum membranes (MAMs) may also participate in the regulation of mitochondrial Ca²⁺ homeostasis and plays an essential role in the progression of HF. Here, we provide an overview of regulation of mitochondrial Ca²⁺ homeostasis in maintenance of cardiac function, in an effort to identify novel therapeutic strategies for the management of HF.

Identifying temporal molecular signatures underlying cardiovascular diseases: A data science platform

OBJECTIVE

During cardiovascular disease progression, molecular systems of myocardium (e.g., a proteome) undergo diverse and distinct changes. Dynamic, temporally-regulated alterations of individual molecules underlie the collective response of the heart to pathological drivers and the ultimate development of pathogenesis. Advances in high-throughput omics technologies have enabled cost-effective, temporal profiling of targeted systems in animal models of human diseases. However, computational analysis of temporal patterns from omics data remains challenging. In particular, bioinformatic pipelines involving unsupervised statistical approaches to support cardiovascular investigations are lacking, which hinders one's ability to extract biomedical insights from these complex datasets.

APPROACH AND RESULTS

We developed a non-parametric data analysis platform to resolve computational challenges unique to temporal omics datasets. Our platform consists of three modules. Module I preprocesses the temporal data using either cubic splines or principal component analysis (PCA), and it simultaneously accomplishes the tasks on missing data imputation and denoising. Module II performs an unsupervised classification by K-means or hierarchical clustering. Module III evaluates and identifies biological entities (e.g., molecular events) that exhibit strong associations to specific temporal patterns. The jackstraw method for cluster membership has been applied to estimate p-values and posterior inclusion probabilities (PIPs), both of which guided feature selection. To demonstrate the utility of the analysis platform, we employed a temporal proteomics dataset that captured the proteome-wide dynamics of oxidative stress induced post-translational modifications (O-PTMs) in mouse hearts undergoing isoproterenol (ISO)-induced hypertrophy.

CONCLUSION

We have created a platform, CV.Signature.TCP, to identify distinct temporal clusters in omics datasets. We presented a cardiovascular use case to demonstrate its utility in unveiling biological insights underlying O-PTM regulations in cardiac remodeling. This platform is implemented in an open source R package (https://github.com/UCLA-BD2K/CV.Signature.TCP).

Review on the Role of Epigenetic Modifications in Doxorubicin-Induced Cardiotoxicity

Use of anthracyclines such as doxorubicin (DOX), for the treatment of cancer, is known to induce cardiotoxicity, begetting numerous evaluations of this adverse effect. This review emphasizes the mechanism of how consideration of DOX-induced cardiotoxicity is important for the development of cardioprotective agents. As DOX is involved in mitochondrial dysfunction, enzymes involved in epigenetic modifications that use mitochondrial metabolite as substrate are most likely to be affected. Therefore, this review article focuses on the fact that epigenetic modifications, namely, DNA methylation, histone modifications, and noncoding RNA expression, contribute to DOX-associated cardiotoxicity. Early interventions needed for patients undergoing chemotherapy, to treat or prevent heart failure, would, overall, improve the survival, and quality of life of cancer patients. These epigenetic modifications can either be used as molecular markers for cancer prognosis or represent molecular targets to attenuate DOX-induced cardiotoxicity in cancer patients.