Dilated cardiomyopathy: causes, mechanisms, and current and future treatment approaches

Association between cardiovascular risk factors and dilated and hypertrophic cardiomyopathy: Mendelian randomization analysis

BACKGROUND AND AIM

Dilated cardiomyopathy is a major cause of heart failure, and hypertrophic cardiomyopathy is a common cause of sudden cardiac death in young adults. Epidemiological studies reporting the association between these cardiomyopathies and common cardiovascular risk factors, including smoking, alcohol, and obesity, are limited, and the published studies are mostly observational, making them vulnerable to bias.

METHODS AND RESULTS

We performed a two-sample Mendelian randomization analysis to assess whether cardiovascular risk factors were causally associated with dilated and hypertrophic cardiomyopathies. Independent genetic variants associated with body mass index, smoking, and alcohol were selected as instrumental variables, with two sets of instrumental variables utilized for alcohol. Dilated cardiomyopathy data on 355,318 samples and hypertrophic cardiomyopathy data on 489,727 samples were obtained from a European population-based genome-wide association study (GWAS) meta-analysis. The large GWAS data sample size improved the statistical power. Our results showed significant associations between a genetic predisposition for smoking and the risk of dilated cardiomyopathy (odds ratio (OR) = 1.33; 95 % confidence level (CI): 1.07-1.67; p = 0.012) and between a genetic predisposition for obesity and the risk of dilated cardiomyopathy (OR = 1.62; 95 % CI, 1.30-2.02; p = 1.51 × 10-5). The results of the other associations were not significant.

CONCLUSIONS

This study suggests that smoking and obesity are causally associated with an increased risk of dilated cardiomyopathy.

Ambiguous Clinical Presentations and Imaging Findings in Genetic Dilated Cardiomyopathy

This case series underscores the crucial role of genetic testing and a multidisciplinary approach to the management of genetic dilated cardiomyopathy. It also highlights the importance of distinguishing dilated cardiomyopathies from other cardiomyopathies to personalize patient care.

Unraveling the nexus of nesprin in dilated cardiomyopathy: From molecular insights to therapeutic prospects

Dilated cardiomyopathy is a complex and debilitating heart disorder characterized by the enlargement and weakening of the cardiac chambers, leading to impaired contractility and heart failure. Nesprins, a family of nuclear envelope spectrin repeat proteins that include isoforms Nesprin-1/-2, are integral components of the LInker of Nucleoskeleton and Cytoskeleton complex. They facilitate the connection between the nuclear envelope and the cytoskeleton, crucial for maintaining nuclear architecture, migration and positioning, and mechanical transduction and signaling. Nesprin-1/-2 are abundantly expressed in cardiac and skeletal muscles.They have emerged as key players in the pathogenesis of dilated cardiomyopathy. Mutations in synaptic nuclear envelope-1/-2 genes encoding Nesprin-1/-2 are associated with dilated cardiomyopathy, underscoring their significance in cardiac health. This review highlights the all known cases of Nesprin-1/-2 related dilated cardiomyopathy, focusing on their interactions with the nuclear envelope, their role in mechanical transduction, and their influence on gene expression. Moreover, it delves into the underlying mechanisms through which Nesprin dysfunction disrupts nuclear-cytoskeletal coupling, leading to abnormal nuclear morphology, impaired mechanotransduction, and altered gene regulation. The exploration of Nesprin's impact on dilated cardiomyopathy offers a promising avenue for therapeutic interventions aimed at ameliorating the disease. This review provides a comprehensive overview of recent advancements in understanding the pivotal role of Nesprins in dilated cardiomyopathy research.

Prognostic value of preoperative high-sensitivity C-reactive protein to albumin ratio in patients with dilated cardiomyopathy receiving pacemaker therapy: A retrospective two-center study in China

Background

Despite receiving pacemaker therapy, patients with heart failure with reduced ejection fraction (HFrEF) due to dilated cardiomyopathy (DCM) remain at an increased risk of adverse cardiovascular events. The high-sensitivity C-reactive protein (hs-CRP)-to-albumin ratio (CAR) is a novel indicator. This study aimed to assess the prognostic value of preoperative CAR in this population.

Methods

Patients with DCM who underwent cardiac resynchronization therapy (CRT) or implantable cardiac defibrillator (ICD) implantation for HFrEF between 2018 and 2023 were involved. The primary endpoint was major adverse cardiac events (MACE). Cox regression models were used to investigate predictors for MACE. Receiver operating characteristic (ROC) curve analysis was utilized to evaluate the diagnostic efficacy and identify the optimal cutoff point.

Results

We enrolled 250 patients, of whom 78 experienced MACE. Patients who experienced MACE had a significantly higher CAR than those without MACE (p < 0.001). Multivariate Cox regression analysis indicated CAR as an independent predictor for MACE (hazard ratio = 4.301, 95 % confidence interval [CI] 1.833-10.091, p < 0.001). ROC curve analysis demonstrated the discriminatory ability of CAR in predicting MACE (area under the curve [AUC] = 0.732, 95 % CI 0.666-0.792, p < 0.001), with an optimal threshold of 0.08. Furthermore, the incidence of MACE was significantly higher in the high-CAR (> 0.08) group compared to the low-CAR (≤ 0.08) group (48.8 % vs. 13.6 %, p < 0.001).

Conclusion

Among patients with DCM and HFrEF treated with CRT or ICD, CAR can serve as an independent risk predictor, with higher levels associated with poorer outcomes.

Downregulation of miR-214 promotes dilated Cardiomyopathy Progression through PDE5A-Mediated cGMP regulation

Dilated cardiomyopathy (DCM) is a myocardial disorder resulting in a substantial decline in cardiac function and potentially leading to heart failure. This research combines bioinformatics analysis with empirical validation to explore the roles and mechanisms of miR-214 in DCM. Using the DEseq2 R package, a total of 125 differentially expressed circulating miRNAs (DE c-miRNAs) and 784 DE genes (DEGs) were identified. Cross-analysis between target genes of DE c-miRNAs and DEGs identified 124 common genes, and protein-protein interaction analysis of common genes identified 11 hub genes. Twelve DE c-miRNAs were further verified by quantifying their levels in the serum of DCM patients and healthy individuals. miR-214 levels were significantly decreased in serum from DCM patients, positively correlated with left ventricular ejection fraction and left ventricular fractional shortening. Further analysis showed that miR-214 directly targets and negatively regulates phosphodiesterase 5 A (PDE5A). Elevated PDE5A expression reduced cGMP levels; however, using sildenafil, a PDE5A inhibitor, reversed this effect, substantiating the regulatory mechanism of miR-214 on cGMP via PDE5A. These results provide new potential targets for the diagnosis and treatment of DCM.

SnRNA-seq reveals differential functional transcriptional pathway alterations in three mutant types of dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a leading cause of heart failure, characterized by ventricular dilation, thinning of the ventricular walls, and systolic dysfunction in either the left or both ventricles, often accompanied by fibrosis. Human cardiac tissue is composed of various cell types, including cardiomyocytes (CMs), fibroblasts (FBs), endothelial cells (ECs), macrophages, lymphocytes and so on. In DCM patients, these cells frequently undergo functional and phenotypic changes, contributing to contractile dysfunction, inflammation, fibrosis, and cell death, thereby increasing the risk of heart failure. This study focuses on DCM patients with mutations (LMNA, RBM20, and TTN) and analyzes functional changes in subpopulations of four cardiac cell types. The study involves functional annotation of subpopulations within each cell type and explores the association between gene mutations and specific functions and pathways. Additionally, the SCENIC method is employed of a particular cell subpopulation with significant functional importance, aiming to identify key transcriptional regulators in specific cell states. By analyzing the expression levels of ligand-receptor pairs in vCM4, vFB2, EC5.0, T cells, and NK cells across the DCM mutant genotypes, we predicted their signaling pathways and communications. This research provides insights into the molecular mechanisms of DCM and potential therapeutic targets.

Leukocyte infiltration and cross-talk with cardiomyocytes exploit intracellular stress pathways in dilated cardiomyopathy of idiopathic origin

BACKGROUND AND OBJECTIVE

Dilated cardiomyopathy (DCM) is a prevalent form of heart failure results in dilation and disruption of heart. Most strikingly a majority of the DCM cases do not have any identified etiology, hence known as idiopathic DCM (IDCM). Our study aimed to investigate the cross-talk between leukocytes and cardiomyocytes in terms of cardiac inflammation and stress response in IDCM.

METHODS

60 IDCM patients and 60 age and sex matched healthy volunteers were recruited in this study based on the New York Heart Association (NYHA) guidelines. Their echocardiographic and biochemical markers were assessed and PBMCs were analyzed for leukocyte migration and inflammation. Also C2C12 myocyte cells were cultured with LPS-activated RAW264.7 monocytes to investigate the cross-talk between them.

RESULTS

Left ventricular (LV) dysfunction was evident in the IDCM patients which were correlated with their physical discomfort level according to NYHA classification. Their serum levels of IL-1β and TNF-α (≈ 20 pg/ml) were found to be very high along with hs-CRP and IL-2. Elevated levels of ROCK, SMA and ICAM-1 proteins indicated activation and migration of the leukocytes. During monocyte-myocyte co-culture, robust diapedesis was observed in the cultured macrophage cells towards myocytes through the transwell pores (8 µM) in presence of IL-1β and TNF-α causing ER stress and cell death in the myocytes. Inhibition of this migration or by alleviating ER stress inhibits leukocyte recruitment and ensures protection to the myocytes.

CONCLUSION

The present study showed that alleviating cellular stress and managing leukocyte migration promotes protection to the heart.

Pathophysiology of dilated cardiomyopathy: from mechanisms to precision medicine

Dilated cardiomyopathy (DCM) is a complex disease with multiple causes and various pathogenic mechanisms. Despite improvements in the prognosis of patients with DCM in the past decade, this condition remains a leading cause of heart failure and premature death. Conventional treatment for DCM is based on the foundational therapies for heart failure with reduced ejection fraction. However, increasingly, attention is being directed towards individualized treatments and precision medicine. The ability to confirm genetic causality is gradually being complemented by an increased understanding of genotype-phenotype correlations. Non-genetic factors also influence the onset of DCM, and growing evidence links genetic background with concomitant non-genetic triggers or precipitating factors, increasing the extreme complexity of the pathophysiology of DCM. This Review covers the spectrum of pathophysiological mechanisms in DCM, from monogenic causes to the coexistence of genetic abnormalities and triggering environmental factors (the 'two-hit' hypothesis). The roles of common genetic variants in the general population and of gene modifiers in disease onset and progression are also discussed. Finally, areas for future research are highlighted, particularly novel therapies, such as small molecules, RNA and gene therapy, and measures for the prevention of arrhythmic death.

LncRNA MAAMT facilitates macrophage recruitment and proinflammatory activation and exacerbates autoimmune myocarditis through the SRSF1/NF-κB axis

Long non-coding RNAs (lncRNAs) have been implicated in dilated cardiomyopathy (DCM). However, the biological functions and regulatory mechanisms of lncRNAs in DCM remain elusive. Using a mouse model of experimental autoimmune myocarditis (EAM) to mimic DCM, we successfully constructed a dynamic lncRNA expression library for EAM by lncRNA microarray and found that the expression of a macrophage-enriched lncRNA, MAAMT, was significantly increased in the myocardial tissue of mice at the acute stage of EAM. Functionally, MAAMT knockdown alleviated the recruitment and proinflammatory activation of macrophages in the heart, spleen, and peripheral blood of mice at the acute stage of EAM, reduced myocardial inflammation and injury, and eventually reversed ventricular remodelling and improved cardiac function in mice at the chronic stage of EAM. Mechanistically, we identified serine/arginine-rich splicing factor 1 (SRSF1) as an MAAMT-interacting protein in macrophages using RNA pull-down assays coupled with mass spectrometry. MAAMT knockdown attenuated the ubiquitination-mediated degradation of SRSF1, increased the protein expression of SRSF1, and restrained the activation of the NF-κB pathway in macrophages, thereby inhibiting the proinflammatory activation of macrophages. Collectively, our results demonstrate that MAAMT is a key proinflammatory regulator of myocarditis that promotes macrophage activation through the SRSF1-NF-κB axis, providing a new insight into early effective treatment strategies for DCM.

Exercise Alleviates Cardiovascular Diseases by Improving Mitochondrial Homeostasis

Engaging in regular exercise and physical activity contributes to delaying the onset of cardiovascular diseases (CVDs). However, the physiological mechanisms underlying the benefits of regular exercise or physical activity in CVDs remain unclear. The disruption of mitochondrial homeostasis is implicated in the pathological process of CVDs. Exercise training effectively delays the onset and progression of CVDs by significantly ameliorating the disruption of mitochondrial homeostasis. This includes improving mitochondrial biogenesis, increasing mitochondrial fusion, decreasing mitochondrial fission, promoting mitophagy, and mitigating mitochondrial morphology and function. This review provides a comprehensive overview of the benefits of physical exercise in the context of CVDs, establishing a connection between the disruption of mitochondrial homeostasis and the onset of these conditions. Through a detailed examination of the underlying molecular mechanisms within mitochondria, the study illuminates how exercise can provide innovative perspectives for future therapies for CVDs.

Targeting OGF/OGFR signal to mitigate doxorubicin-induced cardiotoxicity

Enkephalins are reportedly correlated with heart function. However, their regulation in the heart remains unexplored. This study revealed a substantial increase in circulating levels of opioid growth factor (OGF) (also known as methionine enkephalin) and myocardial expression levels of both OGF and its receptor (OGFR) in subjects treated with doxorubicin (Dox). Silencing OGFR through gene knockout or using adeno-associated virus serotype 9 carrying small hairpin RNA effectively alleviated Dox-induced cardiotoxicity (DIC) in mice. Conversely, OGF supplementation exacerbated DIC manifestations, which could be abolished by administration of the OGFR antagonist naltrexone (NTX). Mechanistically, the previously characterized OGF/OGFR/P21 axis was identified to facilitate DIC-related cardiomyocyte apoptosis. Additionally, OGFR was observed to dissociate STAT1 from the promoters of ferritin genes (FTH and FTL), thereby repressing their transcription and exacerbating DIC-related cardiomyocyte ferroptosis. To circumvent the compromised therapeutic effects of Dox on tumors owing to OGFR blockade, SiO2-based modifiable lipid nanoparticles were developed for heart-targeted delivery of NTX. The pretreatment of tumor-bearing mice with the assembled NTX nanodrug successfully provided cardioprotection against Dox toxicity without affecting Dox therapy in tumors. Taken together, this study provides a novel understanding of Dox cardiotoxicity and sheds light on the development of cardioprotectants for patients with tumors receiving Dox treatment.

Causal association between 1400 metabolites and dilated cardiomyopathy: a bidirectional two-sample Mendelian randomization analysis

Background

Dilated cardiomyopathy (DCM) is a cardiac disease with a poor prognosis of unclear etiology. Previous studies have shown that metabolism is associated with DCM. This study investigates the causal relationship between 1400 metabolites and DCM using a two-sample Mendelian randomization (MR) approach.

Methods

The study utilized data from the OpenGWAS database, comprising 355,381 Europeans, including 1,444 DCM cases. A total of 1,400 metabolites were evaluated for their causal association with DCM. Instrumental variables (IVs) were selected based on genetic variation and used in the MR analysis. The primary analysis method was inverse variance weighting (IVW), supplemented by weighted median-based estimation and sensitivity analyses.

Results

Of the 1,400 metabolites analyzed, 52 were identified as causally associated with DCM. The analysis revealed both positively and negatively correlated metabolites with DCM risk. Notable findings include the positive correlation of Tryptophan betaine and 5-methyluridine (ribothymidine) levels, and an inverse association of Myristoleate and Erythronate levels with DCM.

Conclusions

The study provides significant insights into the metabolites potentially involved in the pathogenesis of DCM. These findings could pave the way for new therapeutic strategies and biomarker identification in DCM management.

Plasma Olink Proteomics Reveals Novel Biomarkers for Prediction and Diagnosis in Dilated Cardiomyopathy with Heart Failure

In this study, we utilized the Olink Cardiovascular III panel to compare the expression levels of 92 cardiovascular-related proteins between patients with dilated cardiomyopathy combined with heart failure (DCM-HF) (n = 20) and healthy normal people (Normal) (n = 18). The top five most significant proteins, including SPP1, IGFBP7, F11R, CHI3L1, and Plaur, were selected by Olink proteomics. These proteins were further validated using ELISA in plasma samples collected from an additional cohort. ELISA validation confirmed significant increases in SPP1, IGFBP7, F11R, CHI3L1, and Plaur in DCM-HF patients compared to healthy controls. GO and KEGG analysis indicated that NT-pro BNP, SPP1, IGFBP7, F11R, CHI3L1, Plaur, BLM hydrolase, CSTB, Gal-4, CCL15, CDH5, SR-PSOX, and CCL2 were associated with DCM-HF. Correlation analysis revealed that these 13 differentially expressed proteins have strong correlations with clinical indicators such as LVEF and NT-pro BNP, etc. Additionally, in the GEO-DCM data sets, the combined diagnostic value of these five core proteins AUC values of 0.959, 0.773, and 0.803, respectively indicating the predictive value of the five core proteins for DCM-HF. Our findings suggest that these proteins may be useful biomarkers for the diagnosis and prediction of DCM-HF, and further research is prompted to explore their potential as therapeutic targets.

Identification of senescence related hub genes and potential therapeutic compounds for dilated cardiomyopathy via comprehensive transcriptome analysis

BACKGROUND

Dilated cardiomyopathy (DCM) is a common cause of heart failure. However, the role of cellular senescence in DCM has not been fully elucidated. Here, we aimed to investigate senescence in DCM, identify senescence related characteristic genes, and explore the potential small molecule compounds for DCM treatment.

METHODS

DCM-associated datasets and senescence-related genes were respectively obtained from Gene Expression Omnibus (GEO) database and CellAge database. The characteristic genes were identified through methods including weighted gene co-expression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO), and random forest. The expression of characteristic genes was verified in the mouse DCM model. Moreover, the CIBERSORT algorithm was applied to analyze immune characteristics of DCM. Finally, several therapeutic compounds were predicted by CMap analysis, and the potential mechanism of chlorogenic acid (CGA) was investigated by molecular docking and molecular dynamics simulation.

RESULTS

Three DCM- and senescence-related characteristic genes (MME, GNMT and PLA2G2A) were ultimately identified through comprehensive transcriptome analysis, and were experimentally verified in the doxorubicin induced mouse DCM. Meanwhile, the established diagnostic model, derived from dataset analysis, showed ideal diagnostic performance for DCM. Immune cell infiltration analysis suggested dysregulation of inflammation in DCM, and the characteristic genes were significantly associated with invasive immune cells. Finally, based on the specific gene expression profile of DCM, several potential therapeutic compounds were predicted through CMap analysis. In addition, molecular docking and molecular dynamics simulations suggested that CGA could bind to the active pocket of MME protein.

CONCLUSION

Our study presents three characteristic genes (MME, PLA2G2A, and GNMT) and a novel senescence-based diagnostic nomogram, and discusses potential therapeutic compounds, providing new insights into the diagnosis and treatment of DCM.

Unravelling the impact of RNA methylation genetic and epigenetic machinery in the treatment of cardiomyopathy

Cardiomyopathy (CM) represents a heterogeneous group of diseases primarily affecting cardiac structure and function, with genetic and epigenetic dysregulation playing a pivotal role in its pathogenesis. Emerging evidence from the burgeoning field of epitranscriptomics has brought to light the significant impact of various RNA modifications, notably N6-methyladenosine (m6A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N1-methyladenosine (m1A), 2'-O-methylation (Nm), and 6,2'-O-dimethyladenosine (m6Am), on cardiomyocyte function and the broader processes of cardiac and vascular remodelling. These modifications have been shown to influence key pathological mechanisms including mitochondrial dysfunction, oxidative stress, cardiomyocyte apoptosis, inflammation, immune response, and myocardial fibrosis. Importantly, aberrations in the RNA methylation machinery have been observed in human CM cases and animal models, highlighting the critical role of RNA methylating enzymes and their potential as therapeutic targets or biomarkers for CM. This review underscores the necessity for a deeper understanding of RNA methylation processes in the context of CM, to illuminate novel therapeutic avenues and diagnostic tools, thereby addressing a significant gap in the current management strategies for this complex disease.

Exploring the etiology of dilated cardiomyopathy using Mendelian randomization

Background

Observational clinical studies suggest an association between dilated cardiomyopathy (DCM) and various factors including titin, cardiac troponin I (CTnI), desmocollin-2, the perinatal period, alcoholism, Behçet's disease, systemic lupus erythematosus, hyperthyroidism and thyrotoxicosis, hypothyroidism, carnitine metabolic disorder, and renal insufficiency. The causal nature of these associations remains uncertain. This study aims to explore these correlations using the Mendelian randomization (MR) approach.

Objective

To investigate the etiology of DCM through Mendelian randomization analysis.

Methods

Data mining was conducted in genome-wide association study databases, focusing on variant target proteins (titin, CTnI, desmocollin-2), the perinatal period, alcoholism, Behçet's disease, systemic lupus erythematosus, hyperthyroidism and thyrotoxicosis, hypothyroidism, carnitine metabolic disorder, and renal insufficiency, with DCM as the outcome. The analysis employed various regression models, namely, the inverse-variance weighted (IVW), MR-Egger, simple mode, weighted median, and weighted mode methods.

Results

The IVW results showed a correlation between titin protein and DCM, identifying titin as a protective factor [OR = 0.856, 95% CI (0.744-0.985), P = 0.030]. CTnI protein correlated with DCM, marking it as a risk factor [OR = 1.204, 95% CI (1.010-1.436), P = 0.040]. Desmocollin-2 also correlated with DCM and was recognized as a risk factor [OR = 1.309, 95% CI (1.085-1.579), P = 0.005]. However, no causal relationship was found between the perinatal period, alcoholism, Behçet's disease, systemic lupus erythematosus, hyperthyroidism and thyrotoxicosis, hypothyroidism, carnitine metabolic disorder, renal insufficiency, and DCM (P > 0.05). The MR-Egger intercept test indicated no pleiotropy (P > 0.05), affirming the effectiveness of Mendelian randomization in causal inference.

Conclusion

Titin, CTnI, and desmocollin-2 proteins were identified as independent risk factors for DCM. Contrasting with previous observational studies, no causal relationship was observed between DCM and the perinatal period, alcoholism, Behçet's disease, systemic lupus erythematosus, hyperthyroidism and thyrotoxicosis, hypothyroidism, carnitine metabolic disorder, or renal insufficiency.

Phospholamban Cardiomyopathy Leading to Advanced Heart Failure in an Active Duty Service Member

A phospholamban mutation is a rare genetic cause of dilated cardiomyopathy (DCM). Our case describes a young service member who presented with advanced heart failure and was found to have a familial DCM from an autosomal dominant phospholamban mutation. He ultimately underwent a successful heart transplant just 23 days after his initial presentation. This case highlights the importance of genetic screening and surveillance for patients with a family history of DCM, and it identifies a gap in medical standards for military accession.

Clinical Characteristics and Outcomes of Dilated Cardiomyopathy in Chinese Children: A Single-Center Retrospective Study

BACKGROUND

The reported outcomes of pediatric dilated cardiomyopathy (DCM) have varied across studies. There are few outcome data concerning DCM in Chinese children. Therefore, we conducted a retrospective study to describe clinical features and determine risk factors for poor outcomes in children with DCM.

METHODS

We enrolled 121 children with DCM in our hospital from 2003 to 2021. General information and laboratory and echocardiographic data were collected and analyzed. Cox regression analysis was performed to determine risk factors for poor outcomes.

RESULTS

This study included 121 patients (69 males and 52 females). The median age at diagnosis was 10.8 years, and the follow-up time was 10.0 months. Eighty-two patients (67.8%) exhibited cardiac function classes III-IV at the time of diagnosis. Tachypnea was the most common symptom (78.5%). In echocardiography, the mean left ventricular end-diastolic dimension z score was 7.36 ± 2.73, and the left ventricular ejection fraction z score was -6.58 ± 2.17. The 1-, 2-, and 5-year survival rates were 51.2%, 43.8%, and 32.2%, respectively. Cox analysis revealed that cardiac function classes III-IV (hazard ratio [HR] = 1.801, 95% confidence interval [95% CI] = 1.030-3.149, p = 0.039) and calcium levels (HR = 0.219, 95% CI = 0.084-0.576, p = 0.002) were predictors of poor outcomes in children with DCM.

CONCLUSIONS

Children with DCM are at high risk of death. Cardiac function class III-IV and calcium levels were related to the prognosis of pediatric DCM patients.

Circular RNA in Cardiovascular Diseases: Biogenesis, Function and Application

Cardiovascular diseases pose a significant public health challenge globally, necessitating the development of effective treatments to mitigate the risk of cardiovascular diseases. Recently, circular RNAs (circRNAs), a novel class of non-coding RNAs, have been recognized for their role in cardiovascular disease. Aberrant expression of circRNAs is closely linked with changes in various cellular and pathophysiological processes within the cardiovascular system, including metabolism, proliferation, stress response, and cell death. Functionally, circRNAs serve multiple roles, such as acting as a microRNA sponge, providing scaffolds for proteins, and participating in protein translation. Owing to their unique properties, circRNAs may represent a promising biomarker for predicting disease progression and a potential target for cardiovascular drug development. This review comprehensively examines the properties, biogenesis, and potential mechanisms of circRNAs, enhancing understanding of their role in the pathophysiological processes impacting cardiovascular disease. Furthermore, the prospective clinical applications of circRNAs in the diagnosis, prognosis, and treatment of cardiovascular disease are addressed.

Effect and mechanism of T lymphocytes on human induced pluripotent stem cell-derived cardiomyocytes via Proteomics

BACKGROUND

Abnormalities in T cell activation play an important role in the pathogenesis of myocarditis, and persistent T cell responses can lead to autoimmunity and chronic cardiac inflammation, as well as even dilated cardiomyopathy. Although previous work has examined the role of T cells in myocarditis in animal models, the specific mechanism for human cardiomyocytes has not been investigated.

METHODS

In this study, we constructed the human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and established the T cell-mediated cardiac injury model by co-culturing with activated CD4 + T or CD8 + T cells that were isolated from peripheral mononuclear blood to elucidate the pathogenesis of myocardial cell injury caused by inflammation.

RESULTS

By combination of quantitative proteomics with tissue and cell immunofluorescence examination, we established a proteome profile of inflammatory myocardia from hiPSC-CMs with obvious cardiomyocyte injury and increased levels of lactate dehydrogenase content, creatine kinase isoenzyme MB and cardiac troponin. A series of molecular dysfunctions of hiPSC-CMs was observed and indicated that CD4 + cells could produce direct cardiomyocyte injury by activating the NOD-like receptor signals pathway.

CONCLUSIONS

The data presented in our study established a proteome map of inflammatory myocardial based on hiPSC-CMs injury model. These results can provide guidance in the discovery of improved clinical treatments for myocarditis.

The E2F family: a ray of dawn in cardiomyopathy

Cardiomyopathies are a group of heterogeneous diseases, characterized by abnormal structure and function of the myocardium. For many years, it has been a hot topic because of its high morbidity and mortality as well as its complicated pathogenesis. The E2Fs, a group of transcription factors found extensively in eukaryotes, play a crucial role in governing cell proliferation, differentiation, and apoptosis, meanwhile their deregulated activity can also cause a variety of diseases. Based on accumulating evidence, E2Fs play important roles in cardiomyopathies. In this review, we describe the structural and functional characteristics of the E2F family and its role in cardiomyocyte processes, with a focus on how E2Fs are associated with the onset and development of cardiomyopathies. Moreover, we discuss the great potential of E2Fs as biomarkers and therapeutic targets, aiming to provide a reference for future research.

Evolving Strategies for Use of Phytochemicals in Prevention and Long-Term Management of Cardiovascular Diseases (CVD)

This report describes major pathomechanisms of disease in which the dysregulation of host inflammatory processes is a major factor, with cardiovascular disease (CVD) as a primary model, and reviews strategies for countermeasures based on synergistic interaction between various agents, including drugs and generally regarded as safe (GRAS) natural medical material (NMM), such as Ginkgo biloba, spice phytochemicals, and fruit seed flavonoids. The 15 well-defined CVD classes are explored with particular emphasis on the extent to which oxidative stressors and associated ischemia-reperfusion tissue injury contribute to major symptoms. The four major categories of pharmaceutical agents used for the prevention of and therapy for CVD: statins, beta blockers (β-blockers), blood thinners (anticoagulants), and aspirin, are presented along with their adverse effects. Analyses of major cellular and molecular features of drug- and NMM-mediated cardioprotective processes are provided in the context of their development for human clinical application. Future directions of the evolving research described here will be particularly focused on the characterization and manipulation of calcium- and calcineurin-mediated cascades of signaling from cell surface receptors on cardiovascular and immune cells to the nucleus, with the emergence of both protective and pathological epigenetic features that may be modulated by synergistically-acting combinations of drugs and phytochemicals in which phytochemicals interact with cells to promote signaling that reduces the effective dosage and thus (often) toxicity of drugs.

Sudden Cardiac Death, Post-Mortem Investigation: A Proposing Panel of First Line and Second Line Genetic Tests

Investigating the causes of Sudden cardiac death (SCD) is always difficult; in fact, genetic cardiac conditions associated with SCD could be "silent" even during autopsy investigation. In these cases, it is important to exclude other aetiology and assist to ask for genetic investigations. Herein, the purpose of this review is to collect the most-implicated genes in SCD and generate a panel with indications for first line and second line investigations. A systematic review of genetic disorders that may cause SCD in the general population was carried out according to the Preferred Reporting Item for Systematic Review (PRISMA) standards. We subsequently listed the genes that may be tested in the case of sudden cardiac death when the autopsy results are negative or with no evidence of acquired cardiac conditions. To make genetic tests more specific and efficient, it is useful and demanded to corroborate autopsy findings with the molecular investigation as evident in the panel proposed. The genes for first line investigations are HCM, MYBPC3, MYH7, TNNT2, TNNI3, while in case of DCM, the most implicated genes are LMNA and TTN, and in second line for these CDM, ACTN2, TPM1, C1QPB could be investigated. In cases of ACM/ARVC, the molecular investigation includes DSP, DSG2, DSC2, RYR2, PKP2. The channelopathies are associated with the following genes: SCN5A, KCNQ1, KCNH2, KCNE1, RYR2. Our work underlines the importance of genetic tests in forensic medicine and clinical pathology; moreover, it could be helpful not only to assist the pathologists to reach a diagnosis, but also to prevent other cases of SCD in the family of the descendant and to standardise the type of analysis performed in similar cases worldwide.

Efficacy and Safety of Kuoxin Formula in the Treatment of Dilated Cardiomyopathy-Related Heart Failure: Study Protocol of a Randomized, Double-Blind, Placebo-Controlled, Multi-Center Clinical Trial

Background

Dilated cardiomyopathy (DCM) is a severe heterogeneous cardiomyopathy characterized by cardiac enlargement and declining heart function, often leading to refractory heart failure and life-threatening outcomes, particularly prevalent in China. The challenge lies in the scarcity of targeted therapies with substantial efficacy for DCM. Additionally, traditional anti-heart failure drugs are constrained due to hypotension propensity or limited symptom improvement. Kuoxin Formula (KXF), internally endorsed at Longhua Hospital, demonstrates clear biological evidence for enhancing cardiac function and myocardial remodeling. Previous clinical studies suggest its potential to enhance patients' quality of life. This trial aims to further evaluate KXF's safety and efficacy in managing DCM-related heart failure.

Methods

This prospective, randomized, double-blind, placebo-controlled, multicenter trial aims to recruit 230 DCM patients from five centers. Participants will be randomly assigned to either KXF or placebo for 12 weeks, with careful monitoring of key indicators and adverse events. The primary outcome measures the proportion of patients with NT-proBNP reduction exceeding 30%. Secondary outcomes include New York Heart Association functional classification, Traditional Chinese Medicine syndrome scores, 6-minute walk test, Lee's heart failure score, and Minnesota Heart Failure Quality of Life Scale score. Ventricular remodeling will be assessed using cardiac ultrasound and ELISA. Safety metrics and adverse events will be meticulously recorded.

Discussion

This study will be the first multicentered research conducted in China that utilizes a randomized, double-blind, placebo-controlled design to investigate the use of TCM in the treatment of DCM. It seeks to develop new theoretical frameworks and provide solid clinical data to support the integration of TCM and modern medicine in treating heart failure in DCM patients.

Trial Registration

China Clinical Trial Registry, ChiCTR2300068937. Registered on March 1, 2023. https://www.chictr.org.cn/bin/project/edit?pid=190926.

Variants in structural cardiac genes in patients with cancer therapy-related cardiac dysfunction after anthracycline chemotherapy: a case control study

BACKGROUND

Variants in cardiomyopathy genes have been identified in patients with cancer therapy-related cardiac dysfunction (CTRCD), suggesting a genetic predisposition for the development of CTRCD. The diagnostic yield of genetic testing in a CTRCD population compared to a cardiomyopathy patient cohort is not yet known and information on which genes should be assessed in this population is lacking.

METHODS

We retrospectively included 46 cancer patients with a history of anthracycline induced CTRCD (defined as a decrease in left ventricular ejection fraction (LVEF) to < 50% and a ≥ 10% reduction from baseline by echocardiography). Genetic testing was performed for 59 established cardiomyopathy genes. Only variants of uncertain significance and (likely) pathogenic variants were included. Diagnostic yield of genetic testing was compared with a matched cohort of patients with dilated cardiomyopathy (DCM, n = 46) and a matched cohort of patients without cardiac disease (n = 111).

RESULTS

Average LVEF at time of CTRCD diagnosis was 30.1 ± 11.0%. Patients were 52.9 ± 14.6 years old at time of diagnosis and 30 (65.2%) were female. Most patients were treated for breast cancer or lymphoma, with a median doxorubicin equivalent dose of 300 mg/m2 [112.5-540.0]. A genetic variant, either pathogenic, likely pathogenic or of uncertain significance, was identified in 29/46 (63.0%) of patients with CTRCD, which is similar to the DCM cohort (34/46, 73.9%, p = 0.262), but significantly higher than in the negative control cohort (47/111, 39.6%, p = 0.018). Variants in TTN were the most prevalent in the CTRCD cohort (43% of all variants). All (likely) pathogenic variants identified in the CTRCD cohort were truncating variants in TTN. There were no significant differences in severity of CTRCD and in recovery rate in variant-harbouring individuals versus non-variant harbouring individuals.

CONCLUSIONS

In this case-control study, cancer patients with anthracycline-induced CTRCD have an increased burden of genetic variants in cardiomyopathy genes, similar to a DCM cohort. If validated in larger prospective studies, integration of genetic data in risk prediction models for CTRCD may guide cancer treatment. Moreover, genetic results have important clinical impact, both for the patient in the setting of precision medicine, as for the family members that will receive genetic counselling.

The Role of Magnetic Resonance Imaging in Cardiomyopathies in the Light of New Guidelines: A Focus on Tissue Mapping

Cardiomyopathies (CMPs) are a group of myocardial disorders that are characterized by structural and functional abnormalities of the heart muscle. These abnormalities occur in the absence of coronary artery disease (CAD), hypertension, valvular disease, and congenital heart disease. CMPs are an increasingly important topic in the field of cardiovascular diseases due to the complexity of their diagnosis and management. In 2023, the ESC guidelines on cardiomyopathies were first published, marking significant progress in the field. The growth of techniques such as cardiac magnetic resonance imaging (CMR) and genetics has been fueled by the development of multimodal imaging approaches. For the diagnosis of CMPs, a multimodal imaging approach, including CMR, is recommended. CMR has become the standard for non-invasive analysis of cardiac morphology and myocardial function. This document provides an overview of the role of CMR in CMPs, with a focus on tissue mapping. CMR enables the characterization of myocardial tissues and the assessment of cardiac functions. CMR sequences and techniques, such as late gadolinium enhancement (LGE) and parametric mapping, provide detailed information on tissue composition, fibrosis, edema, and myocardial perfusion. These techniques offer valuable insights for early diagnosis, prognostic evaluation, and therapeutic guidance of CMPs. The use of quantitative CMR markers enables personalized treatment plans, improving overall patient outcomes. This review aims to serve as a guide for the use of these new tools in clinical practice.

PBX/Knotted 1 homeobox-2 (PKNOX2) is a novel regulator of myocardial fibrosis

Much effort has been made to uncover the cellular heterogeneities of human hearts by single-nucleus RNA sequencing. However, the cardiac transcriptional regulation networks have not been systematically described because of the limitations in detecting transcription factors. In this study, we optimized a pipeline for isolating nuclei and conducting single-nucleus RNA sequencing targeted to detect a higher number of cell signal genes and an optimal number of transcription factors. With this unbiased protocol, we characterized the cellular composition of healthy human hearts and investigated the transcriptional regulation networks involved in determining the cellular identities and functions of the main cardiac cell subtypes. Particularly in fibroblasts, a novel regulator, PKNOX2, was identified as being associated with physiological fibroblast activation in healthy hearts. To validate the roles of these transcription factors in maintaining homeostasis, we used single-nucleus RNA-sequencing analysis of transplanted failing hearts focusing on fibroblast remodelling. The trajectory analysis suggested that PKNOX2 was abnormally decreased from fibroblast activation to pathological myofibroblast formation. Both gain- and loss-of-function in vitro experiments demonstrated the inhibitory role of PKNOX2 in pathological fibrosis remodelling. Moreover, fibroblast-specific overexpression and knockout of PKNOX2 in a heart failure mouse model induced by transverse aortic constriction surgery significantly improved and aggravated myocardial fibrosis, respectively. In summary, this study established a high-quality pipeline for single-nucleus RNA-sequencing analysis of heart muscle. With this optimized protocol, we described the transcriptional regulation networks of the main cardiac cell subtypes and identified PKNOX2 as a novel regulator in suppressing fibrosis and a potential therapeutic target for future translational studies.

Role of Treg cell subsets in cardiovascular disease pathogenesis and potential therapeutic targets

In the genesis and progression of cardiovascular diseases involving both innate and adaptive immune responses, inflammation plays a pivotal and dual role. Studies in experimental animals indicate that certain immune responses are protective, while others exacerbate the disease. T-helper (Th) 1 cell immune responses are recognized as key drivers of inflammatory progression in cardiovascular diseases. Consequently, the CD4+CD25+FOXP3+ regulatory T cells (Tregs) are gaining increasing attention for their roles in inflammation and immune regulation. Given the critical role of Tregs in maintaining immune-inflammatory balance and homeostasis, abnormalities in their generation or function might lead to aberrant immune responses, thereby initiating pathological changes. Numerous preclinical studies and clinical trials have unveiled the central role of Tregs in cardiovascular diseases, such as atherosclerosis. Here, we review the roles and mechanisms of Treg subsets in cardiovascular conditions like atherosclerosis, hypertension, myocardial infarction and remodeling, myocarditis, dilated cardiomyopathy, and heart failure. While the precise molecular mechanisms of Tregs in cardiac protection remain elusive, therapeutic strategies targeting Tregs present a promising new direction for the prevention and treatment of cardiovascular diseases.

Familial Dilated Cardiomyopathy: A Novel MED9 Short Isoform Identification

Familial dilated cardiomyopathy (DCM) is among the leading indications for heart transplantation. DCM alters the transcriptomic profile. The alteration or activation/silencing of physiologically operating transcripts may explain the onset and progression of this pathological state. The mediator complex (MED) plays a fundamental role in the transcription process. The aim of this study is to investigate the MED subunits, which are altered in DCM, to identify target crossroads genes. RNA sequencing allowed us to identify specific MED subunits that are altered during familial DCM, transforming into human myocardial samples. N = 13 MED subunits were upregulated and n = 7 downregulated. MED9 alone was significantly reduced in patients compared to healthy subjects (HS) (FC = -1.257; p < 0.05). Interestingly, we found a short MED9 isoform (MED9s) (ENSG00000141026.6), which was upregulated when compared to the full-transcript isoform (MED9f). Motif identification analysis yielded several significant matches (p < 0.05), such as GATA4, which is downregulated in CHD. Moreover, although the protein-protein interaction network showed FOG2/ZFPM2, FOS and ID2 proteins to be the key interacting partners of GATA4, only FOG2/ZFPM2 overexpression showed an interaction score of "high confidence" ≥ 0.84. A significant change in the MED was observed during HF. For the first time, the MED9 subunit was significantly reduced between familial DCM and HS (p < 0.05), showing an increased MED9s isoform in DCM patients with respect to its full-length transcript. MED9 and GATA4 shared the same sequence motif and were involved in a network with FOG2/ZFPM2, FOS, and ID2, proteins already implicated in cardiac development.

Ginsenoside RH4 inhibits Ang II-induced myocardial remodeling by interfering with NFIL3

Ventricular remodeling refers to the structural and functional changes of the heart under various stimuli or disease influences and may also be accompanied by myocardial fibrosis, where an excessive amount of fibrous tissue appears in the myocardial tissue, affecting the heart's normal contraction and relaxation. Hypertension is posing the potential risk of causing myocardial injury and remodeling. The significance of the renin-angiotensin-aldosterone system (RAAS) in myocardial remodeling cannot be overlooked. Drug targeting of RAAS can effectively lower blood pressure and reduce left ventricular mass. Studies have shown that ginsenoside Rh4 can inhibit oxidative stress and inflammatory responses. In this study, a myocardial remodeling model was established using angiotensin (Ang) II, and the inhibitory effect of RH4 on myocardial hypertrophy and remodeling induced by Ang II was investigated using pathological staining and quantitative polymerase chain reaction (qPCR). Immunofluorescence and qPCR demonstrated that Rh4 causes myocardial hypertrophy and the generation of reactive oxygen species (ROS) in vitro. The Rh4 target was identified using transcriptomics. The findings indicated that RH4 could inhibit myocardial hypertrophy, inflammatory fibrosis, and oxidative stress induced by Ang II, suggesting potential cardiovascular protection effects. In vitro experiments have shown that Rh4 inhibits myocardial hypertrophy. Transcriptomics revealed that nuclear factor interleukin-3 (NFIL3) is a downstream regulator of Rh4. By constructing AAV9-NFIL3 and injecting it into mice, it was found that NFIL3 overexpression interfered with anti-Ang II-induced myocardial remodeling of Rh4. These results indicate that Rh4 demonstrates potential therapeutic effects on myocardial hypertrophy and fibrosis.

Integrated analysis of differentially expressed genes and miRNA expression profiles in dilated cardiomyopathy

Background

Although dilated cardiomyopathy (DCM) is a prevalent form of cardiomyopathy, the molecular mechanisms underlying its pathogenesis and progression remain poorly understood. It is possible to identify and validate DCM-associated genes, pathways, and miRNAs using bioinformatics analysis coupled with clinical validation methods.

Methods

Our analysis was performed using 3 mRNA datasets and 1 miRNA database. We employed several approaches, including gene ontology (GO) analysis, KEGG pathway enrichment analysis, protein-protein interaction networks analysis, and analysis of hub genes to identify critical genes and pathways linked to DCM. We constructed a regulatory network for DCM that involves interactions between miRNAs and mRNAs. We also validated the differently expressed miRNAs in clinical samples (87 DCM ，83 Normal) using qRT-PCR.The miRNAs' clinical value was evaluated by receiver operating characteristic curves (ROCs).

Results

78 differentially expressed genes (DEGs) and 170 differentially expressed miRNAs (DEMs) were associated with DCM. The top five GO annotations were collagen-containing extracellular matrix, cell substrate adhesion, negative regulation of cell differentiation, and inflammatory response. The most enriched KEGG pathways were the Neurotrophin signaling pathway, Thyroid hormone signaling pathway, Wnt signaling pathway, and Axon guidance. In the PPI network, we identified 10 hub genes, and in the miRNA-mRNA regulatory network, we identified 8 hub genes and 15 miRNAs. In the clinical validation, we found 13 miRNAs with an AUC value greater than 0.9.

Conclusion

Our research offers novel insights into the underlying mechanisms of DCM and has implications for identifying potential targets for diagnosis and treatment of this condition.

The Prognostic Value of Serum Calcium Levels in Elderly Dilated Cardiomyopathy Patients

Background

It is unclear whether serum calcium on admission is associated with clinical outcomes in dilated cardiomyopathy (DCM). In this study, we conducted a retrospective study spanning a decade to investigate the prognostic value of baseline calcium in elderly patients with DCM.

Methods

A total of 1,089 consecutive elderly patients (age ≥60 years) diagnosed with DCM were retrospectively enrolled from January 2010 to December 2019. Univariate and multivariate analyses were performed to investigate the association of serum calcium with their clinical outcomes.

Results

In this study, the average age of the subjects was 68.36 ± 6.31 years. Receiver operating characteristic (ROC) curve analysis showed that serum calcium level had a great sensitivity and specificity for predicting in-hospital death, with an AUC of 0.732. Kaplan-Meier survival analysis showed that patients with a serum calcium >8.62 mg/dL had a better prognosis than those with a serum calcium ≤8.62 mg/dL (log-rank χ2 40.84, p < 0.001). After adjusting for several common risk factors, a serum calcium ≤8.62 mg/dL was related to a higher risk of long-term mortality (HR: 1.449; 95% CI: 1.115~1.882; p = 0.005).

Conclusions

Serum calcium level could be served as a simple and affordable tool to evaluate patients' prognosis in DCM.

Comprehensive review on gene mutations contributing to dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the most common primary myocardial diseases. However, to this day, it remains an enigmatic cardiovascular disease (CVD) characterized by ventricular dilatation, which leads to myocardial contractile dysfunction. It is the most common cause of chronic congestive heart failure and the most frequent indication for heart transplantation in young individuals. Genetics and various other factors play significant roles in the progression of dilated cardiomyopathy, and variants in more than 50 genes have been associated with the disease. However, the etiology of a large number of cases remains elusive. Numerous studies have been conducted on the genetic causes of dilated cardiomyopathy. These genetic studies suggest that mutations in genes for fibronectin, cytoskeletal proteins, and myosin in cardiomyocytes play a key role in the development of DCM. In this review, we provide a comprehensive description of the genetic basis, mechanisms, and research advances in genes that have been strongly associated with DCM based on evidence-based medicine. We also emphasize the important role of gene sequencing in therapy for potential early diagnosis and improved clinical management of DCM.