Molecular Basis of Inflammation in the Pathogenesis of Cardiomyopathies

Necroptosis and immune infiltration in hypertrophic cardiomyopathy: novel insights from bioinformatics analyses

Background

Hypertrophic Cardiomyopathy (HCM), a widespread genetic heart disorder, is largely associated with sudden cardiac fatality. Necroptosis, an emerging type of programmed cell death, plays a fundamental role in several cardiovascular diseases.

Aim

This research utilized bioinformatics analysis to investigate necroptosis's implication in HCM.

Methods

The study retrieved RNA sequencing datasets GSE130036 and GSE141910 from the Gene Expression Omnibus (GEO) database. It detected necroptosis-linked differentially expressed genes (NRDEGs) by reviewing both the gene set for necroptosis and the differently expressed genes (DEGs). The enriched signaling pathway of HCM was assessed using GSEA, while common DEGs were studied through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Concurrently, the Protein-Protein Interaction network (PPI) proved useful for identifying central genes. CIBERSORT facilitated evaluating the correlation between distinct immune cell-type prevalence and NRDEGs by analyzing immune infiltration patterns. Lastly, GSE141910 dataset validated the expression ranks of NRDEGs and immune-cell penetration.

Results

The investigation disclosed significant enrichment and activation of the necroptosis pathway in HCM specimens. Seventeen diverse genes, including CYBB, BCL2, and JAK2 among others, were identified in the process. PPI network scrutiny classified nine of these genes as central genes. Results from GO and KEGG enrichment analyses showed substantial connections of these genes to pathways pertaining to the HIF-1 signaling track, necroptosis, and NOD-like receptor signaling process. Moreover, an imbalance in M2 macrophage cells in HCM samples was observed. Finally, CYBB, BCL2, and JAK2 emerged as vital genes and were validated using the GSE141910 dataset.

Conclusion

These results indicate necroptosis as a probable underlying factor in HCM, with immune cell infiltration playing a part. Additionally, CYBB, BCL2, JAK2 could act as potential biomarkers for recognizing HCM. This information forms crucial insights into the basic mechanisms of HCM and could enhance its diagnosis and management.

Prevalence of Pathogenic Variants in Cardiomyopathy-Associated Genes in Acute Myocarditis: A Systematic Review and Meta-Analysis

BACKGROUND

Acute myocarditis is an inflammatory condition that may precede the development of dilated or arrhythmogenic cardiomyopathy.

OBJECTIVES

The aim of this study was to investigate the reported prevalence of pathogenic or likely pathogenic (P/LP) variants in cardiomyopathy-associated genes in patients with acute myocarditis.

METHODS

For this systematic review and meta-analysis, the PubMed and Embase databases were searched on March 4, 2023. Observational studies evaluating the prevalence of P/LP variants in cardiomyopathy-associated genes in patients with acute myocarditis were included. Studies were stratified into adult and pediatric age groups and for the following scenarios: 1) complicated myocarditis (ie, presenting with acute heart failure, reduced left ventricular ejection fraction, or life-threatening ventricular arrhythmias); and 2) uncomplicated myocarditis. The study was registered with the International Prospective Register of Systematic Reviews (CRD42023408668) and followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Of 732 studies identified, 8 met the inclusion criteria, providing data for 586 patients with acute myocarditis. A total of 89 P/LP variants in cardiomyopathy-associated genes were reported in 85 patients. For uncomplicated myocarditis, the pooled prevalence was 4.2% (95% CI: 1.8%-7.4%; I2 = 1.4%), whereas for complicated myocarditis, the pooled prevalence was 21.9% (95% CI: 14.3%-30.5%; I2 = 38.8%) and 44.5% (95% CI: 22.7%-67.4%; I2 = 52.8%) in adults and children, respectively. P/LP variants in desmosomal genes were predominant in uncomplicated myocarditis (64%), whereas sarcomeric gene variants were more prevalent in complicated myocarditis (58% in adults and 71% in children).

CONCLUSIONS

Genetic variants are present in a large proportion of patients with acute myocarditis. The prevalence of genetic variants and the genes involved vary according to age and clinical presentation.

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Integrated bioinformatics and experiment revealed that cuproptosis is the potential common pathogenesis of three kinds of primary cardiomyopathy

Cuproptosis is a recently reported new mode of programmed cell death which might be a potential co-pathogenesis of three kinds of primary cardiomyopathy. However, no investigation has reported a clear relevance between primary cardiomyopathy and cuproptosis. In this study, the differential cuproptosis-related genes (CRGs) shared by three kinds of primary cardiomyopathy were identified in training sets. As a result, four CRGs shared by three kinds of primary cardiomyopathy were acquired and they were mainly related to biological processes such as cell death and immuno-inflammatory response through differential analysis, correlation analysis, GSEA, GSVA and immune cell infiltration analysis. Then, three key CRGs (K-CRGs) with high diagnostic value were identified by LASSO regression. The results of nomogram, machine learning, ROC analysis, calibration curve and decision curve indicated that the K-CRGs exhibited outstanding performance in the diagnosis of three kinds of primary cardiomyopathy. After that, in each disease, two molecular subtypes clusters were distinguished. There were many differences between different clusters in the biological processes associated with cell death and immunoinflammation and K-CRGs had excellent molecular subtype identification efficacy. Eventually, results from validation datasets and in vitro experiments verified the role of K-CRGs in diagnosis of primary cardiomyopathy, identification of primary cardiomyopathic molecular subtypes and pathogenesis of cuproptosis. In conclusion, this study found that cuproptosis might be the potential common pathogenesis of three kinds of primary cardiomyopathy and K-CRGs might be promising biomarkers for the diagnosis and molecular subtypes identification of primary cardiomyopathy.

Utilities and Limitations of Cardiac Magnetic Resonance Imaging in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the most common types of non-ischemic cardiomyopathy. DCM is characterized by left ventricle (LV) dilatation and systolic dysfunction without coronary artery disease or abnormal loading conditions. DCM is not a single disease entity and has a complex historical background of revisions and updates to its definition because of its diverse etiology and clinical manifestations. In cases of LV dilatation and dysfunction, conditions with phenotypic overlap should be excluded before establishing a DCM diagnosis. The differential diagnoses of DCM include ischemic cardiomyopathy, valvular heart disease, burned-out hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, and non-compaction. Cardiac magnetic resonance (CMR) imaging is helpful for evaluating DCM because it provides precise measurements of cardiac size, function, mass, and tissue characterization. Comprehensive analyses using various sequences, including cine imaging, late gadolinium enhancement imaging, and T1 and T2 mapping, may help establish differential diagnoses, etiological work-up, disease stratification, prognostic determination, and follow-up procedures in patients with DCM phenotypes. This article aimed to review the utilities and limitations of CMR in the diagnosis and assessment of DCM.

Prognostic value of albumin to fibrinogen ratio for mortality in patients with hypertrophic cardiomyopathy

BACKGROUND

Albumin to fibrinogen ratio (AFR), a new inflammatory marker, has emerged as a useful indicator to predict adverse outcomes for several diseases. However, whether AFR could be a new useful indicator to predict mortality in HCM patients remains to be evaluated. The study explored the predictive value of AFR for HCM-related death in adult HCM patients.

METHODS

A total of 404 HCM patients were eventually enrolled in the study according to the inclusion criteria. Patients were divided into two groups based on the median of baseline AFR. The association between AFR and HCM-related death was analyzed.

RESULTS

During a median follow-up of 4.75 years, HCM-related death was observed in 45 patients (11.1%). The incidence of HCM-related death was significantly higher in the low AFR group (log-rank p < 0.001). With the high AFR group as reference, the unadjusted hazard ratio (HR) for HCM-related death was 2.97 (95% confidence interval [CI]: 1.53-5.75, p = 0.001) in the low AFR group, and after adjusting for potentially confounding variables, the adjusted HR for low AFR group was 3.15 (95% CI: 1.56-6.37, p = 0.001). No significant interactions between AFR and other variables were observed in subgroup analysis. Sensitivity analyses in patients with normal albumin and fibrinogen showed similar results.

CONCLUSION

AFR is an independent prognostic factor for HCM-related death, adult HCM patients with a lower AFR have a higher risk of HCM-related death.

The Molecular Role of Immune Cells in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a rare and severe condition characterized by chamber dilation and impaired contraction of the left ventricle. It constitutes a fundamental etiology for profound heart failure and abrupt cardiac demise, rendering it a prominent clinical indication for heart transplantation (HTx) among both adult and pediatric populations. DCM arises from various etiologies, including genetic variants, epigenetic disorders, infectious insults, autoimmune diseases, and cardiac conduction abnormalities. The maintenance of cardiac function involves two distinct types of immune cells: resident immune cells and recruited immune cells. Resident immune cells play a crucial role in establishing a harmonious microenvironment within the cardiac tissue. Nevertheless, in response to injury, cardiomyocytes initiate a cytokine cascade that attracts peripheral immune cells, thus perturbing this intricate equilibrium and actively participating in the initiation and pathological remodeling of dilated cardiomyopathy (DCM), particularly during the progression of myocardial fibrosis. Additionally, immune cells assume a pivotal role in orchestrating the inflammatory processes, which are intimately linked to the prognosis of DCM. Consequently, understanding the molecular role of various immune cells and their regulation mechanisms would provide an emerging era for managing DCM. In this review, we provide a summary of the most recent advancements in our understanding of the molecular mechanisms of immune cells in DCM. Additionally, we evaluate the effectiveness and limitations of immunotherapy approaches for the treatment of DCM, with the aim of optimizing future immunotherapeutic strategies for this condition.

The Microenvironment of the Pathogenesis of Cardiac Hypertrophy

Pathological cardiac hypertrophy is a key risk factor for the development of heart failure and predisposes individuals to cardiac arrhythmia and sudden death. While physiological cardiac hypertrophy is adaptive, hypertrophy resulting from conditions comprising hypertension, aortic stenosis, or genetic mutations, such as hypertrophic cardiomyopathy, is maladaptive. Here, we highlight the essential role and reciprocal interactions involving both cardiomyocytes and non-myocardial cells in response to pathological conditions. Prolonged cardiovascular stress causes cardiomyocytes and non-myocardial cells to enter an activated state releasing numerous pro-hypertrophic, pro-fibrotic, and pro-inflammatory mediators such as vasoactive hormones, growth factors, and cytokines, i.e., commencing signaling events that collectively cause cardiac hypertrophy. Fibrotic remodeling is mediated by cardiac fibroblasts as the central players, but also endothelial cells and resident and infiltrating immune cells enhance these processes. Many of these hypertrophic mediators are now being integrated into computational models that provide system-level insights and will help to translate our knowledge into new pharmacological targets. This perspective article summarizes the last decades' advances in cardiac hypertrophy research and discusses the herein-involved complex myocardial microenvironment and signaling components.

Inflammation across the spectrum of hypertrophic cardiac phenotypes

The hypertrophic cardiomyopathy phenotype encompasses a heterogeneous spectrum of genetic and acquired diseases characterized by the presence of left ventricular hypertrophy in the absence of abnormal cardiac loading conditions. This "umbrella diagnosis" includes the "classic" hypertrophic cardiomyopathy (HCM), due to sarcomere protein gene mutations, and its phenocopies caused by intra- or extracellular deposits, such as Fabry disease (FD) and cardiac amyloidosis (CA). All these conditions share a wide phenotypic variability which results from the combination of genetic and environmental factors and whose pathogenic mediators are poorly understood so far. Accumulating evidence suggests that inflammation plays a critical role in a broad spectrum of cardiovascular conditions, including cardiomyopathies. Indeed, inflammation can trigger molecular pathways which contribute to cardiomyocyte hypertrophy and dysfunction, extracellular matrix accumulation, and microvascular dysfunction. Growing evidence suggests that systemic inflammation is a possible key pathophysiologic process potentially involved in the pathogenesis of cardiac disease progression, influencing the severity of the phenotype and clinical outcome, including heart failure. In this review, we summarize current knowledge regarding the prevalence, clinical significance, and potential therapeutic implications of inflammation in HCM and two of its most important phenocopies, FD and CA.

Multimodality Imaging in Arrhythmogenic Left Ventricular Cardiomyopathy

The term arrhythmogenic cardiomyopathy (ACM) describes a large spectrum of myocardial diseases characterized by progressive fibrotic or fibrofatty replacement, which gives the substrate for the occurrence of ventricular tachyarrhythmias and the development of ventricular dysfunction. This condition may exclusively affect the left ventricle, leading to the introduction of the term arrhythmogenic left ventricular cardiomyopathy (ALVC). The clinical features of ALVC are progressive fibrotic replacement with the absence or mild dilation of the LV and the occurrence of ventricular arrhythmias within the left ventricle. In 2019, the diagnostic criteria for the diagnosis of ALVC, based on family history and clinical, electrocardiographic, and imaging features, have been proposed. However, since the significant clinical and imaging overlap with other cardiac diseases, genetic testing with the demonstration of a pathogenic variant in an ACM-related gene is required for diagnostic confirmation. In ALVC, the multimodality imaging approach comprises different imaging techniques, such as echocardiography, cardiac magnetic resonance, and cardiac nuclear imaging. It provides essential information for the diagnosis, differential diagnosis, sudden cardiac death risk stratification, and management purposes. This review aims to elucidate the current role of the different multimodality imaging techniques in patients with ALVC.

FOXO3A acts as immune response modulator in human virus-negative inflammatory cardiomyopathy

OBJECTIVE

Inflammatory cardiomyopathy is characterised by inflammatory infiltrates leading to cardiac injury, left ventricular (LV) dilatation and reduced LV ejection fraction (LVEF). Several viral pathogens and autoimmune phenomena may cause cardiac inflammation.The effects of the gain of function FOXO3A single-nucleotide polymorphism (SNP) rs12212067 on inflammation and outcome were studied in a cohort of patients with inflammatory dilated cardiomyopathy (DCMi) in relation to cardiac viral presence.

METHODS

Distribution of the SNP was determined in virus-positive and virus-negative DCMi patients and in control subjects without myocardial pathology. Baseline and outcome data were compared in 221 virus-negative patients with detection of cardiac inflammation and reduced LVEF according to their carrier status of the SNP.

RESULTS

Distribution of SNP rs12212067 did not differ between virus-positive (n=22, 19.3%), virus-negative (n=45, 20.4 %) and control patients (n=18, 23.4 %), indicating the absence of susceptibility for viral infection or inflammation per se (p=0.199). Patients in the virus-negative DCMi group were characterised by reduced LVEF 35.5% (95% CI) 33.5 to 37.4) and increased LVEDD (LV end-diastolic diameter) 59.8 mm (95% CI 58.5 to 61.2). Within the group, SNP and non-SNP carriers had similarly impaired LVEF 39.2% (95% CI 34.3% to 44.0%) vs 34.5% (95% CI 32.4 to 36.5), p=0.083, and increased LVEDD 58.9 mm (95% CI 56.3 to 61.5) vs 60.1 mm (95% CI 58.6 to 61.6), p=0.702, respectively. The number of inflammatory infiltrates was not different in both SNP groups at baseline. Outcome after 6 months showed a significant improvement in LVEF and clinical symptoms in SNP rs12212067 carriers 50.9% (95% CI 45.4 to 56.3) versus non-SNP carriers 41.7% (95% CI 39.2 to 44.2), p≤0.01. The improvement in clinical symptoms and LVEF was associated with a significant reduction in cardiac inflammation (ΔCD45RO⁺ p≤0.05; ΔMac-1⁺ p≤0.05; ΔLFA-1⁺ p≤0.01; ΔCD54⁺ p≤0.01) in the SNP cohort versus non-SNP cohort, respectively. Subgroup analyses identified ΔMac-1⁺, ΔLFA-1⁺, ΔCD3⁺ and Δperforin⁺ as predictors for improvement in cardiac function in SNP-positive patients.

CONCLUSION

FOXO3A might act as modulator of the cardiac immune response, diminishing cardiac inflammation and injury in pathogen-negative DCMi.

News in diagnostics and treament of cardiomyopathies

Cardiomyopathies are defined as myocardial disorders in which the heart muscle is structurally and functionaly abnormal in the absence of a disease sufficient to cause this abnormality such as coronary artery disease, hypertension, valvular or congenital heart disease. According to the phenotype expresion cardiomyopathies are divided into dilated, hypertrophic, restrictive, arrhytmogenic and unclassified cardiomyopathies (noncompaction and tako-tsubo cardiomyopathy). The same phenotypic expression may include etiologically different forms of the disease, and at the same time phenotypic expression may change in many cardiomyopathies in the course of illness. For each type of cardiomyopathy, we further distinguish the familial (genetic) form and the acquired form. The clinical manifestation of the disease includes symptoms of heart failure, with reduced, mildly reduced or preserved ejection fraction, symptoms resulting from a number of arrhythmias and extracardiac symptoms, but in some cases symptoms may not be presented for a relatively long time. The disease can lead to significant morbidity and mortality if not detected and treated early, especially in young people who are frequently affected. Significant developments in diagnostic and treatment methods have led to an improvement in the prognosis of patients with cardiomyopathies in recent years.

Effect of Astragalus injection on inflammatory mediators in patients with viral myocarditis: A systematic review and meta-analysis

BACKGROUND

To explore the therapeutic effect and mechanism of Astragalus injection on viral myocarditis, we conducted a systematic review and meta-analysis to identify the influence of Astragalus injection on inflammatory mediators and overall efficiency in patients undergoing viral myocarditis.

METHODS

EMBASE, Cochrane Library, PubMed, Chinese Biomedical Literature, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases were searched to screen randomized controlled trials (RCTs) published before July 3, 2022. The quality of participating studies was assessed by the Cochrane Collaboration Risk of Bias tool. The calculation of qualitative data used a risk ratio (RR) with a 95% confidence interval (95% CI), and quantitative data had standardized mean differences (SMDs) with a 95% CI. The heterogeneity among trials was quantified with Cochran's Q test and the I² statistic. Confounding factors were estimated by sensitivity analysis, meta-regression, and subgroup analysis. The publication bias of participating articles was evaluated by funnel plot and Egger's test. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was recommended for assessing the strength of evidence.

RESULTS

Nineteen available studies were included in our present meta-analysis, all of which were conducted in China. The outcomes expose that Astragalus injection dramatically decreased the levels of pro-inflammatory TNF-α (SMD=-2.271, 95% CI=-2.802 to -1.739, p<0.001, I²=90.6%), IL-6 (SMD=-1.501, 95% CI=-1.872 to -1.130, p<0.001, I²=83.2%), IL-17 (SMD=-3.194, 95% CI=-4.569 to -1.818, p<0.001, I²=88.9%), 1L-8 (SMD=-6.133, 95% CI=-9.938 to -2.328, p = 0.002, I²=97%), 1L-1 (SMD=-1.814, 95% CI=-2.557 to -1.070, p<0.001, I²=92.1%), CRP (SMD=-2.020, 95% CI=-3.107 to -0.932, p<0.001, I²=92.7%), and IFN-γ (SMD=-1.512, 95% CI=-2.771 to -0.253, p = 0.019, I²=92%) and increased the total effective rate of treatment (RR=1.225, 95% CI=1.17 to 1.29, p<0.001, I²=0.0%) in patients with viral myocarditis.

CONCLUSION

Astragalus injection can play a therapeutic role in patients with viral myocarditis through immunomodulatory effects. Outcomes were treated with caution due to significant heterogeneity among studies. Large-scale RCTs should be performed to support these conclusions.

The prognostic significance of the presence of tenascin-C in patients with stable coronary heart disease

BACKGROUND

We investigated the prognostic value of tenascin-C in patients with stable coronary heart disease.

METHODS

A total of 666 patients were enrolled and followed for 72 months. The primary outcome was a composite of cardiac events. The secondary outcomes were all-cause death, cardiovascular death, acute myocardial infarction (AMI), and heart failure hospitalization.

RESULTS

The area under the curve of tenascin-C to discriminate the occurrence of composite cardiac events was 70 % (95 % CI: 64.2 % to 75.8 %), and the corresponding optimal cutoff value was 19.91 ng/ml. A higher concentration of tenascin-C was associated with a greater risk of composite cardiac events (P trend < 0.001). Similar results were observed in all-cause death, AMI, and heart failure hospitalization.

CONCLUSION

Tenascin-C was found to be an independent predictor of total cardiovascular events in patients with stable coronary heart disease at 72 months, and also for all-cause death, AMI, and heart failure hospitalization.

Dysregulation and imbalance of innate and adaptive immunity are involved in the cardiomyopathy progression

Background

Cardiomyopathy is known to be a heterogeneous disease with numerous etiologies. They all have varying degrees and types of myocardial pathological changes, resulting in impaired contractility, ventricle relaxation, and heart failure. The purpose of this study was to determine the pathogenesis, immune-related pathways and important biomarkers engaged in the progression of cardiomyopathy from various etiologies.

Methods

We downloaded the gene microarray data from the Gene Expression Omnibus (GEO). The hub genes between cardiomyopathy and non-cardiomyopathy control groups were identified using differential expression analysis, least absolute shrinkage and selection operator (LASSO) regression and weighted gene co-expression network analysis (WGCNA). To assess the diagnostic precision of hub genes, receiver-operating characteristic (ROC) curves as well as the area under the ROC curve (AUC) were utilized. Then, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis and Gene Ontology (GO) analysis were conducted on the obtained differential genes. Finally, single-sample GSEA (ssGSEA) and Gene Set Enrichment Analysis (GSEA) were utilized to analyze the infiltration level of 28 immune cells and their relationship with hub genes based on gene expression profile data and all differential gene files.

Results

A total of 82 differentially expressed genes (DEGs) were screened after the training datasets were merged and intersected. The WGCNA analysis clustered the expression profile data into four co-expression modules, The turquoise module exhibited the strongest relationship with clinical traits, and nine candidate key genes were obtained from the module. Then we intersected DEGs with nine candidate genes. LASSO regression analysis identified the last three hub genes as promising biomarkers to distinguish the cardiomyopathy group from the non-cardiomyopathy control group. ROC curve analysis in the validation dataset revealed the sensitivity and accuracy of three hub genes as marker genes. The majority of the functional enrichment analysis results were concentrated on immunological and inflammatory pathways. Immune infiltration analysis revealed a significant correlation between regulatory T cells, type I helper T cells, macrophages, myeloid-derived suppressor cells, natural killer cells, activated dendritic cells and the abundance of immune infiltration in hub genes.

Conclusion

The hub genes (CD14, CCL2, and SERPINA3) can be used as markers to distinguish cardiomyopathy from non-cardiomyopathy individuals. Among them, SERPINA3 has the best diagnostic performance. T cell immunity (adaptive immune response) is closely linked to cardiomyopathy progression. Hub genes may protect the myocardium from injury through myeloid-derived suppressor cells, regulatory T cells, helper T cells, monocytes/macrophages, natural killer cells and activated dendritic cells. The innate immune response is crucial to this process. Dysregulation and imbalance of innate immune cells or activation of adaptive immune responses are involved in cardiomyopathy disease progression in patients.

Dilated cardiomyopathy in the era of precision medicine: latest concepts and developments

Dilated cardiomyopathy (DCM) is an umbrella term entailing a wide variety of genetic and non-genetic etiologies, leading to left ventricular systolic dysfunction and dilatation, not explained by abnormal loading conditions or coronary artery disease. The clinical presentation can vary from asymptomatic to heart failure symptoms or sudden cardiac death (SCD) even in previously asymptomatic individuals. In the last 2 decades, there has been striking progress in the understanding of the complex genetic basis of DCM, with the discovery of additional genes and genotype-phenotype correlation studies. Rigorous clinical work-up of DCM patients, meticulous family screening, and the implementation of advanced imaging techniques pave the way for a more efficient and earlier diagnosis as well as more precise indications for implantable cardioverter defibrillator implantation and prevention of SCD. In the era of precision medicine, genotype-directed therapies have started to emerge. In this review, we focus on updates of the genetic background of DCM, characteristic phenotypes caused by recently described pathogenic variants, specific indications for prevention of SCD in those individuals and genotype-directed treatments under development. Finally, the latest developments in distinguishing athletic heart syndrome from subclinical DCM are described.

Diagnosis and Management of Rare Cardiomyopathies in Adult and Paediatric Patients. A Position Paper of the Italian Society of Cardiology (SIC) and Italian Society of Paediatric Cardiology (SICP)

Cardiomyopathies (CMPs) are myocardial diseases in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality. Thought for a long time to be rare diseases, it is now clear that most of the CMPs can be easily observed in clinical practice. However, there is a group of specific heart muscle diseases that are rare in nature whose clinical/echocardiographic phenotypes resemble those of the four classical morphological subgroups of hypertrophic, dilated, restrictive, arrhythmogenic CMPs. These rare CMPs, often but not solely diagnosed in infants and paediatric patients, should be more properly labelled as specific CMPs. Emerging consensus exists that these conditions require tailored investigation and management. Indeed, an appropriate understanding of these conditions is mandatory for early treatment and counselling. At present, however, the multisystemic and heterogeneous presentation of these entities is a challenge for clinicians, and time delay in diagnosis is a significant concern. The aim of this paper is to define practical recommendations for diagnosis and management of the rare CMPs in paediatric or adult age. A modified Delphi method was adopted to grade the recommendations proposed by each member of the writing committee.

Relation between lymphocyte to monocyte ratio and survival in patients with hypertrophic cardiomyopathy: a retrospective cohort study

Background

The lymphocyte-to-monocyte ratio (LMR) has been proposed as a novel prognostic factor in malignancies and cardiovascular diseases. Our study aimed to ascertain whether LMR is a useful biomarker in discriminating the hypertrophic cardiomyopathy (HCM) patients at higher risk of all-cause mortality.

Methods

This retrospective study consisted of 354 adult HCM patients. Cox's proportional hazards regression models were used to analyze the association between LMR and all-cause mortality. Smooth curve fitting was conducted to explore the linear relationship between LMR and all-cause mortality.

Results

During the follow-up, 44 patients reached the study endpoint. The all-cause mortality rate was 7.3 per 100 person-years in the first tertile and decreased across the three tertiles of LMR. With the first tertile as reference, adjusted hazard ratios (HR) for all-cause mortality were 0.43 for the second tertile (95% CI [0.20-0.91], p = 0.027) and 0.39 for the third tertile (95% CI [0.17-0.90], p = 0.028), respectively. Smooth curve fitting exhibited a nonlinear relationship between LMR values and all-cause mortality. For LMR < 6.5, per SD increase resulted in a significantly decreased risk of all-cause mortality by 62% (HR: 0.38, 95% CI [0.21-0.68]). For LMR ≥ 6.5, the all-cause mortality risk did not progressively increase. Stratified and subgroup analyses revealed similar results to the main analyses,andE-value analysis suggested robustness to unmeasured confounding.

Conclusions

The study demonstrated that LMR was an independent predictor of all-cause mortality in HCM patients, and LMR may be useful for identifying HCM patients at high mortality risk.

Diagnosis of Fabry Disease in a Patient with a Surgically Repaired Congenital Heart Defect: When Clinical History and Genetics Make the Difference

Fabry disease (FD) is a multiorgan disease, which can potentially affect any organ or tissue, with the heart, kidneys, and central nervous system representing the major disease targets. FD can be suspected based on the presence of specific red flags, and the subsequent evaluation of the α-Gal A activity and GLA sequencing, are required to confirm the diagnosis, to evaluate the presence of amenable GLA mutation, and to perform a cascade program screening in family members. An early diagnosis is required to start an etiological treatment and to prevent irreversible organ damage. Here, we describe a case of a 37-years-old patient, with a surgically repaired congenital heart defect in his childhood, who had a late diagnosis of FD based on the clinical history and targeted genetic evaluation. This case highlights the importance to perform a correct phenotyping and definite diagnosis of FD, to start an early and appropriate treatment in the index patient, and a cascade clinical and genetic screening to identify other family members at risk, which may benefit from specific treatment and/or a close follow-up.

Antisense Therapy Attenuates Phospholamban p.(Arg14del) Cardiomyopathy in Mice and Reverses Protein Aggregation

Inherited cardiomyopathy caused by the p.(Arg14del) pathogenic variant of the phospholamban (PLN) gene is characterized by intracardiomyocyte PLN aggregation and can lead to severe dilated cardiomyopathy. We recently reported that pre-emptive depletion of PLN attenuated heart failure (HF) in several cardiomyopathy models. Here, we investigated if administration of a Pln-targeting antisense oligonucleotide (ASO) could halt or reverse disease progression in mice with advanced PLN-R14del cardiomyopathy. To this aim, homozygous PLN-R14del (PLN-R14 ^Δ/Δ) mice received PLN-ASO injections starting at 5 or 6 weeks of age, in the presence of moderate or severe HF, respectively. Mice were monitored for another 4 months with echocardiographic analyses at several timepoints, after which cardiac tissues were examined for pathological remodeling. We found that vehicle-treated PLN-R14 ^Δ/Δ mice continued to develop severe HF, and reached a humane endpoint at 8.1 ± 0.5 weeks of age. Both early and late PLN-ASO administration halted further cardiac remodeling and dysfunction shortly after treatment start, resulting in a life span extension to at least 22 weeks of age. Earlier treatment initiation halted disease development sooner, resulting in better heart function and less remodeling at the study endpoint. PLN-ASO treatment almost completely eliminated PLN aggregates, and normalized levels of autophagic proteins. In conclusion, these findings indicate that PLN-ASO therapy may have beneficial outcomes in PLN-R14del cardiomyopathy when administered after disease onset. Although existing tissue damage was not reversed, further cardiomyopathy progression was stopped, and PLN aggregates were resolved.

Genotype-Phenotype Correlation in Familial BAG3 Mutation Dilated Cardiomyopathy

We report the case of a 22-year-old male who visited a cardiologist after the first episode of atrial fibrillation (AF). Echocardiography and magnetic resonance imaging revealed decreased left ventricular (LV) systolic function with dilated LV. An intermittent second-degree AV (atrioventricular) block was detected during 24 h Holter monitoring. Genetic test revealed the pathogenic variant of the BAG3 (BLC2-associated athanogene 3) gene. Due to the high risk of heart failure (HF) progression and ventricular arrhythmias, an event recorder was implanted and a pathogenetic HF treatment was prescribed. The analysis of genealogy revealed that the patient’s father, at the age of 32, was diagnosed with dilated cardiomyopathy (DCM) and recurrent AF episodes. Genetic testing also confirmed a pathogenic variant of the BAG3 gene. Currently, with the optimal treatment of HF, the patient’s disease has been stable for three years and the condition is closely monitored on an outpatient basis. So, we demonstrate the importance of early detection for genetic testing and the unusual stability exhibited by the patient‘s optimal medical therapy for 3 years.

Multimodality Imaging in Cardiomyopathies with Hypertrophic Phenotypes

Multimodality imaging is a comprehensive strategy to investigate left ventricular hypertrophy (LVH), providing morphologic, functional, and often clinical information to clinicians. Hypertrophic cardiomyopathy (HCM) is defined by an increased LV wall thickness not only explainable by abnormal loading conditions. In the context of HCM, multimodality imaging, by different imaging techniques, such as echocardiography, cardiac magnetic resonance, cardiac computer tomography, and cardiac nuclear imaging, provides essential information for diagnosis, sudden cardiac death stratification, and management. Furthermore, it is essential to uncover the specific cause of HCM, such as Fabry disease and cardiac amyloidosis, which can benefit of specific treatments. This review aims to elucidate the current role of multimodality imaging in adult patients with HCM.

Subcellular Remodeling in Filamin C Deficient Mouse Hearts Impairs Myocyte Tension Development during Progression of Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a life-threatening form of heart disease that is typically characterized by progressive thinning of the ventricular walls, chamber dilation, and systolic dysfunction. Multiple mutations in the gene encoding filamin C (FLNC), an actin-binding cytoskeletal protein in cardiomyocytes, have been found in patients with DCM. However, the mechanisms that lead to contractile impairment and DCM in patients with FLNC variants are poorly understood. To determine how FLNC regulates systolic force transmission and DCM remodeling, we used an inducible, cardiac-specific FLNC-knockout (icKO) model to produce a rapid onset of DCM in adult mice. Loss of FLNC reduced systolic force development in single cardiomyocytes and isolated papillary muscles but did not affect twitch kinetics or calcium transients. Electron and immunofluorescence microscopy showed significant defects in Z-disk alignment in icKO mice and altered myofilament lattice geometry. Moreover, a loss of FLNC induces a softening myocyte cortex and structural adaptations at the subcellular level that contribute to disrupted longitudinal force production during contraction. Spatially explicit computational models showed that these structural defects could be explained by a loss of inter-myofibril elastic coupling at the Z-disk. Our work identifies FLNC as a key regulator of the multiscale ultrastructure of cardiomyocytes and therefore plays an important role in maintaining systolic mechanotransmission pathways, the dysfunction of which may be key in driving progressive DCM.

Inflammation in the Pathogenesis of Arrhythmogenic Cardiomyopathy: Secondary Event or Active Driver?

Arrhythmogenic cardiomyopathy (ACM) is a rare inherited cardiac disease characterized by arrhythmia and progressive fibro-fatty replacement of the myocardium, which leads to heart failure and sudden cardiac death. Inflammation contributes to disease progression, and it is characterized by inflammatory cell infiltrates in the damaged myocardium and inflammatory mediators in the blood of ACM patients. However, the molecular basis of inflammatory process in ACM remains under investigated and it is unclear whether inflammation is a primary event leading to arrhythmia and myocardial damage or it is a secondary response triggered by cardiomyocyte death. Here, we provide an overview of the proposed players and triggers involved in inflammation in ACM, focusing on those studied using in vivo and in vitro models. Deepening current knowledge of inflammation-related mechanisms in ACM could help identifying novel therapeutic perspectives, such as anti-inflammatory therapy.

Diagnosis and Management of Cardiovascular Involvement in Fabry Disease

Fabry disease (FD, OMIM 301500) is an X-linked lysosomal storage disease caused by pathogenic variants in the GLA gene. Cardiac involvement is common in FD and is responsible for impaired quality of life and premature death. The classic cardiac involvement is a nonobstructive form of hypertrophic cardiomyopathy, usually manifesting as concentric left ventricular hypertrophy, with subsequent arrhythmogenic intramural fibrosis. Treatment of patients with FD should be directed to prevent the disease progression to irreversible organ damage and organ failure. The aim of this review is to describe the current state of knowledge regarding cardiovascular involvement in FD, focusing on clinical and instrumental features, cardiovascular management, and targeted therapy.

The Risk of Sudden Unexpected Cardiac Death in Children: Epidemiology, Clinical Causes, and Prevention

"Sudden unexplained death (SUD) is a tragic event for both the family and community, particularly when it occurs in young individuals. Sudden cardiac death (SCD) represents the leading form of SUD and is defined as an unexpected event without an obvious extracardiac cause, occurring within 1 hour after the onset of symptoms. In children, the main causes of SCD are inherited cardiac disorders, whereas coronary artery diseases (congenital or acquired), congenital heart diseases, and myocarditis are rare. The present review examines the current state of knowledge regarding SCD in children, discussing the epidemiology, clinical causes, and prevention strategies."

Viral Myocarditis-From Pathophysiology to Treatment

The diagnosis of acute and chronic myocarditis remains a challenge for clinicians. Characterization of this disease has been hampered by its diverse etiologies and heterogeneous clinical presentations. Most cases of myocarditis are caused by infectious agents. Despite successful research in the last few years, the pathophysiology of viral myocarditis and its sequelae leading to severe heart failure with a poor prognosis is not fully understood and represents a significant public health issue globally. Most likely, at a certain point, besides viral persistence, several etiological types merge into a common pathogenic autoimmune process leading to chronic inflammation and tissue remodeling, ultimately resulting in the clinical phenotype of dilated cardiomyopathy. Understanding the underlying molecular mechanisms is necessary to assess the prognosis of patients and is fundamental to appropriate specific and personalized therapeutic strategies. To reach this clinical prerequisite, there is the need for advanced diagnostic tools, including an endomyocardial biopsy and guidelines to optimize the management of this disease. The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has currently led to the worst pandemic in a century and has awakened a special sensitivity throughout the world to viral infections. This work aims to summarize the pathophysiology of viral myocarditis, advanced diagnostic methods and the current state of treatment options.

Cardiovascular consequences of viral infections: from COVID to other viral diseases

Infection of the heart muscle with cardiotropic viruses is one of the major aetiologies of myocarditis and acute and chronic inflammatory cardiomyopathy (DCMi). However, viral myocarditis and subsequent dilated cardiomyopathy is still a challenging disease to diagnose and to treat and is therefore a significant public health issue globally. Advances in clinical examination and thorough molecular genetic analysis of intramyocardial viruses and their activation status have incrementally improved our understanding of molecular pathogenesis and pathophysiology of viral infections of the heart muscle. To date, several cardiotropic viruses have been implicated as causes of myocarditis and DCMi. These include, among others, classical cardiotropic enteroviruses (Coxsackieviruses B), the most commonly detected parvovirus B19, and human herpes virus 6. A newcomer is the respiratory virus that has triggered the worst pandemic in a century, SARS-CoV-2, whose involvement and impact in viral cardiovascular disease is under scrutiny. Despite extensive research into the pathomechanisms of viral infections of the cardiovascular system, our knowledge regarding their treatment and management is still incomplete. Accordingly, in this review, we aim to explore and summarize the current knowledge and available evidence on viral infections of the heart. We focus on diagnostics, clinical relevance and cardiovascular consequences, pathophysiology, and current and novel treatment strategies.

The Emerging Role of Epigenetics in Therapeutic Targeting of Cardiomyopathies

Cardiomyopathies (CMPs) are a heterogeneous group of myocardial diseases accountable for the majority of cases of heart failure (HF) and/or sudden cardiac death (SCD) worldwide. With the recent advances in genomics, the original classification of CMPs on the basis of morphological and functional criteria (dilated (DCM), hypertrophic (HCM), restrictive (RCM), and arrhythmogenic ventricular cardiomyopathy (AVC)) was further refined into genetic (inherited or familial) and acquired (non-inherited or secondary) forms. Despite substantial progress in the identification of novel CMP-associated genetic variations, as well as improved clinical recognition diagnoses, the functional consequences of these mutations and the exact details of the signaling pathways leading to hypertrophy, dilation, and/or contractile impairment remain elusive. To date, global research has mainly focused on the genetic factors underlying CMP pathogenesis. However, growing evidence shows that alterations in molecular mediators associated with the diagnosis of CMPs are not always correlated with genetic mutations, suggesting that additional mechanisms, such as epigenetics, may play a role in the onset or progression of CMPs. This review summarizes published findings of inherited CMPs with a specific focus on the potential role of epigenetic mechanisms in regulating these cardiac disorders.

Analysis of Immune Associated Co-Expression Networks Reveals Immune-Related Long Non-Coding RNAs during MI in the Presence and Absence of HDC

Myocardial infarction (MI) is one of the most common cardiovascular diseases. Although previous studies have shown that histidine decarboxylase (HDC), a histamine-synthesizing enzyme, is involved in the stress response and heart remodeling after MI, the mechanism underlying it remains unclear. In this study, using Hdc-deficient mice (Hdc-/- mice), we established an acute myocardial infarction mouse model to explore the potential roles of Hdc/histamine in cardiac immune responses. Comprehensive analysis was performed on the transcriptomes of infarcted hearts. Differentially expressed gene (DEG) analysis identified 2126 DEGs in Hdc-deficient groups and 1013 in histamine-treated groups. Immune related pathways were enriched in Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Then we used the ssGSEA algorithm to evaluate 22 kinds of infiltrated immunocytes, which indicated that myeloid cells and T memory/follicular helper cells were tightly regulated by Hdc/histamine post MI. The relationships of lncRNAs and the Gene Ontology (GO) functions of protein-coding RNAs and immunocytes were dissected in networks to unveil immune-associated lncRNAs and their roles in immune modulation after MI. Finally, we screened out and verified four lncRNAs, which were closely implicated in tuning the immune responses after MI, including ENSMUST00000191157, ENSMUST00000180693 (PTPRE-AS1), and ENSMUST-00000182785. Our study highlighted the HDC-regulated myeloid cells as a driving force contributing to the government of transmission from innate immunocytes to adaptive immunocytes in the progression of the injury response after MI. We identified the potential role of the Hdc/histamine-lncRNAs network in regulating cardiac immune responses, which may provide novel promising therapeutic targets for further promoting the treatment of ischemic heart disease.

Tenascin-C in Heart Diseases-The Role of Inflammation

Tenascin-C (TNC) is a large extracellular matrix (ECM) glycoprotein and an original member of the matricellular protein family. TNC is transiently expressed in the heart during embryonic development, but is rarely detected in normal adults; however, its expression is strongly up-regulated with inflammation. Although neither TNC-knockout nor -overexpressing mice show a distinct phenotype, disease models using genetically engineered mice combined with in vitro experiments have revealed multiple significant roles for TNC in responses to injury and myocardial repair, particularly in the regulation of inflammation. In most cases, TNC appears to deteriorate adverse ventricular remodeling by aggravating inflammation/fibrosis. Furthermore, accumulating clinical evidence has shown that high TNC levels predict adverse ventricular remodeling and a poor prognosis in patients with various heart diseases. Since the importance of inflammation has attracted attention in the pathophysiology of heart diseases, this review will focus on the roles of TNC in various types of inflammatory reactions, such as myocardial infarction, hypertensive fibrosis, myocarditis caused by viral infection or autoimmunity, and dilated cardiomyopathy. The utility of TNC as a biomarker for the stratification of myocardial disease conditions and the selection of appropriate therapies will also be discussed from a clinical viewpoint.

Combined Effect of Mediterranean Diet and Aerobic Exercise on Weight Loss and Clinical Status in Obese Symptomatic Patients with Hypertrophic Cardiomyopathy

We evaluated the impact of weight loss (WL) using a Mediterranean diet and mild-to-moderate-intensity aerobic exercise program, on clinical status of obese, symptomatic patients with hypertrophic cardiomyopathy (HCM). Compared with nonresponders, responders showed a significant reduction of left atrial diameter, left atrial volume index (LAVI), E/E'average, pulmonary artery systolic pressure (PASP), and a significant increase in Vo_2max (%) and peak workload. Body mass index changes correlated with reduction in left atrial diameter, LAVI, E/E'average, PASP, and increase of Vo_2max (mL/Kg/min), Vo_2max (%), peak workload. Mediterranean diet and aerobic exercise is associated with clinical-hemodynamic improvement in obese symptomatic HCM patients.

Prognostic nutritional index and the risk of mortality in patients with hypertrophic cardiomyopathy

AIMS

Nutritional status has been related to clinical outcomes in patients with cardiovascular diseases. The prognostic impact of poor nutritional status in hypertrophic cardiomyopathy (HCM) is not clearly understood. The aim of the present study is to investigate the prognostic value of prognostic nutritional index (PNI), calculated from serum albumin level and total lymphocyte count, in HCM patients.

METHODS

A total of 393 HCM patients in a tertiary medical centre were enrolled. The primary and secondary endpoints were all-cause mortality and cardiovascular death. The association between PNI and endpoints was analysed.

RESULTS

During a mean follow-up duration of 4.8 years, patients with high PNI values (PNI ≥ 48.8) had significantly lower incidence of all-cause mortality (9.3% vs. 33.1%, P < 0.001) and cardiovascular death (7.1% vs. 21.0%, P < 0.001). After adjusting for potential confounders, PNI was independently associated with all-cause mortality and cardiovascular death (hazard ratio per 1 SD increase: 0.46 [95% CI: 0.34-0.62, P < 0.001] and 0.44 [95% CI: 0.30-0.63, P < 0.001]). In subgroup analysis stratified by age, gender, New York Heart Association class, atrial fibrillation, estimated glomerular filtration rate, left ventricular ejection fraction or left ventricular outflow tract obstruction, PNI was consistently related to mortality.

CONCLUSIONS

PNI is an independent prognostic factor for mortality in patients with HCM.

Hypertrophic Cardiomyopathy in Children: Pathophysiology, Diagnosis, and Treatment of Non-sarcomeric Causes

Hypertrophic cardiomyopathy (HCM) is a myocardial disease characterized by left ventricular hypertrophy not solely explained by abnormal loading conditions. Despite its rare prevalence in pediatric age, HCM carries a relevant risk of mortality and morbidity in both infants and children. Pediatric HCM is a large heterogeneous group of disorders. Other than mutations in sarcomeric genes, which represent the most important cause of HCM in adults, childhood HCM includes a high prevalence of non-sarcomeric causes, including inherited errors of metabolism (i.e., glycogen storage diseases, lysosomal storage diseases, and fatty acid oxidation disorders), malformation syndromes, neuromuscular diseases, and mitochondrial disease, which globally represent up to 35% of children with HCM. The age of presentation and the underlying etiology significantly impact the prognosis of children with HCM. Moreover, in recent years, different targeted approaches for non-sarcomeric etiologies of HCM have emerged. Therefore, the etiological diagnosis is a fundamental step in designing specific management and therapy in these subjects. The present review aims to provide an overview of the non-sarcomeric causes of HCM in children, focusing on the pathophysiology, clinical features, diagnosis, and treatment of these rare disorders.