Association Between Clonal Hematopoiesis and Left Ventricular Reverse Remodeling in Nonischemic Dilated Cardiomyopathy.

Although clonal hematopoiesis of indeterminate potential (CHIP) is an adverse prognostic factor for atherosclerotic disease, its impact on nonischemic dilated cardiomyopathy (DCM) is elusive. The authors performed whole-exome sequencing and deep target sequencing among 198 patients with DCM and detected germline mutations in cardiomyopathy-related genes and somatic mutations in CHIP driver genes. Twenty-five CHIP driver mutations were detected in 22 patients with DCM. Ninety-two patients had cardiomyopathy-related pathogenic mutations. Multivariable analysis revealed that CHIP was an independent risk factor of left ventricular reverse remodeling, irrespective of known prognostic factors. CHIP exacerbated cardiac systolic dysfunction and fibrosis in a DCM murine model. The identification of germline and somatic mutations in patients with DCM predicts clinical prognosis.

[Para-anastomotic Aneurysm in the Ascending Aorta Late After Aortic Valve Replacement:Report of Two Cases].

Case 1 was a 59-year-old man who underwent aortic valve replacement (AVR) at the age of 38, for aortic regurgitation. Case 2 was a 51-year-old man who underwent AVR at the age of 34, for aortic regurgitation. Both cases required surgery for ascending aortic aneurysms. These patients showed aneurysm at the site of the prior aortotomy. In both of the patients used felt-strip was used for closing aortotomy. Intraoperative findings showed enlargement of the aorta around the felt-strip, which was a finding of true aneurysm. Both cases underwent ascending aortic replacement. The mechanism of aortic aneurysm development was thought to include persistent mechanical stimulation by the felt-strip and ischemia of the vasa-vasorum due to compression of the felt-strip. The use of felt-strips for the aortotomy suture should be avoided, especially in young patients.

Vaccine Therapy for Heart Failure Targeting the Inflammatory Cytokine Igfbp7.

BACKGROUND: The heart comprises many types of cells such as cardiomyocytes, endothelial cells (ECs), fibroblasts, smooth muscle cells, pericytes, and blood cells. Every cell type responds to various stressors (eg, hemodynamic overload and ischemia) and changes its properties and interrelationships among cells. To date, heart failure research has focused mainly on cardiomyocytes; however, other types of cells and their cell-to-cell interactions might also be important in the pathogenesis of heart failure. METHODS: Pressure overload was imposed on mice by transverse aortic constriction and the vascular structure of the heart was examined using a tissue transparency technique. Functional and molecular analyses including single-cell RNA sequencing were performed on the hearts of wild-type mice and EC-specific gene knockout mice. Metabolites in heart tissue were measured by capillary electrophoresis-time of flight-mass spectrometry system. The vaccine was prepared by conjugating the synthesized epitope peptides with keyhole limpet hemocyanin and administered to mice with aluminum hydroxide as an adjuvant. Tissue samples from heart failure patients were used for single-nucleus RNA sequencing to examine gene expression in ECs and perform pathway analysis in cardiomyocytes. RESULTS: Pressure overload induced the development of intricately entwined blood vessels in murine hearts, leading to the accumulation of replication stress and DNA damage in cardiac ECs. Inhibition of cell proliferation by a cyclin-dependent kinase inhibitor reduced DNA damage in ECs and ameliorated transverse aortic constriction-induced cardiac dysfunction. Single-cell RNA sequencing analysis revealed upregulation of Igfbp7 (insulin-like growth factor-binding protein 7) expression in the senescent ECs and downregulation of insulin signaling and oxidative phosphorylation in cardiomyocytes of murine and human failing hearts. Overexpression of Igfbp7 in the murine heart using AAV9 (adeno-associated virus serotype 9) exacerbated cardiac dysfunction, while EC-specific deletion of Igfbp7 and the vaccine targeting Igfbp7 ameliorated cardiac dysfunction with increased oxidative phosphorylation in cardiomyocytes under pressure overload. CONCLUSIONS: Igfbp7 produced by senescent ECs causes cardiac dysfunction and vaccine therapy targeting Igfbp7 may be useful to prevent the development of heart failure.

Successful treatment of fulminant and recurrent lymphocytic myocarditis with calcineurin inhibitors.

Lymphocytic myocarditis (LM) is primarily triggered by various factors including viral infections and subsequent immune responses. While rare, some patients with LM experience recurrence with a life-threatening fulminant form. Although combining steroids and immunosuppressants, such as azathioprine and mycophenolate mofetil, has demonstrated favourable outcomes in patients with LM, their efficacy is limited to the chronic phase. Indeed, various immunosuppressants have been used for LM with fulminant manifestation; however, their evidence remains lacking. In our case series, two patients with LM experienced fulminant relapses during steroid tapering, and another presented persistent cardiac enzymes elevation despite steroid therapies. Consequently, we initiated calcineurin inhibitors alongside steroids, resulting in well-controlled clinical courses without further recurrence of LM and significant adverse effects. Our cases suggest calcineurin inhibitors as therapeutic options for managing steroid-resistant LM with fulminant relapse.

Myocardial DNA Damage Predicts Heart Failure Outcome in Various Underlying Diseases.

BACKGROUND: Reliable predictors of treatment efficacy in heart failure have been long awaited. DNA damage has been implicated as a cause of heart failure. OBJECTIVES: The purpose of this study was to investigate the association of DNA damage in myocardial tissue with treatment response and prognosis of heart failure. METHODS: The authors performed immunostaining of DNA damage markers poly(ADP-ribose) (PAR) and γ-H2A.X in endomyocardial biopsy specimens from 175 patients with heart failure with reduced ejection fraction (HFrEF) of various underlying etiologies. They calculated the percentage of nuclei positive for each DNA damage marker (%PAR and %γ-H2A.X). The primary outcome was left ventricular reverse remodeling (LVRR) at 1 year, and the secondary outcome was a composite of cardiovascular death, heart transplantation, and ventricular assist device implantation. RESULTS: Patients who did not achieve LVRR after the optimization of medical therapies presented with significantly higher %PAR and %γ-H2A.X. The ROC analysis demonstrated good performance of both %PAR and %γ-H2A.X for predicting LVRR (AUCs: 0.867 and 0.855, respectively). There was a negative correlation between the mean proportion of DNA damage marker-positive nuclei and the probability of LVRR across different underlying diseases. In addition, patients with higher %PAR or %γ-H2A.X had more long-term clinical events (PAR HR: 1.63 [95% CI: 1.31-2.01]; P < 0.001; γ-H2A.X HR: 1.48 [95% CI: 1.27-1.72]; P < 0.001). CONCLUSIONS: DNA damage determines the consequences of human heart failure. Assessment of DNA damage is useful to predict treatment efficacy and prognosis of heart failure patients with various underlying etiologies.

Differential cardiomyocyte transcriptomic remodeling during in vitro Trypanosoma cruzi infection using laboratory strains provides implications on pathogenic host responses.

BACKGROUND: Chagas disease can lead to life-threatening cardiac manifestations. Regional factors, including genetic characteristics of circulating Trypanosoma cruzi (T. cruzi), have attracted attention as likely determinants of Chagas disease phenotypic expression and Chagas cardiomyopathy (CCM) progression. Our objective was to elucidate the differential transcriptomic signatures of cardiomyocytes resulting from infection with genetically discrete T. cruzi strains and explore their relationships with CCM pathogenesis and progression. METHODS: HL-1 rodent cardiomyocytes were infected with T. cruzi trypomastigotes of the Colombian, Y, or Tulahuen strain. RNA was serially isolated post-infection for microarray analysis. Enrichment analyses of differentially expressed genes (fold-change ≥ 2 or ≤ 0.5) highlighted over-represented biological pathways. Intracellular levels of reactive oxygen species (ROS) were compared between T. cruzi-infected and non-infected HL-1 cardiomyocytes. RESULTS: We found that oxidative stress-related gene ontology terms (GO terms), 'Hypertrophy model', 'Apoptosis', and 'MAPK signaling' pathways (all with P < 0.01) were upregulated. 'Glutathione and one-carbon metabolism' pathway, and 'Cellular nitrogen compound metabolic process' GO term (all with P < 0.001) were upregulated exclusively in the cardiomyocytes infected with the Colombian/Y strains. Mean intracellular levels of ROS were significantly higher in the T. cruzi-infected cardiomyocytes compared to the non-infected (P < 0.0001). CONCLUSIONS: The upregulation of oxidative stress-related and hypertrophic pathways constitutes the universal hallmarks of the cardiomyocyte response elicited by T. cruzi infection. Nitrogen metabolism upregulation and glutathione metabolism imbalance may implicate a relationship between nitrosative stress and poor oxygen radicals scavenging in the unique pathophysiology of Chagas cardiomyopathy.

TEAD1 trapping by the Q353R-Lamin A/C causes dilated cardiomyopathy.

Mutations in the LMNA gene encoding Lamin A and C (Lamin A/C), major components of the nuclear lamina, cause laminopathies including dilated cardiomyopathy (DCM), but the underlying molecular mechanisms have not been fully elucidated. Here, by leveraging single-cell RNA sequencing (RNA-seq), assay for transposase-accessible chromatin using sequencing (ATAC-seq), protein array, and electron microscopy analysis, we show that insufficient structural maturation of cardiomyocytes owing to trapping of transcription factor TEA domain transcription factor 1 (TEAD1) by mutant Lamin A/C at the nuclear membrane underlies the pathogenesis of Q353R-LMNA-related DCM. Inhibition of the Hippo pathway rescued the dysregulation of cardiac developmental genes by TEAD1 in LMNA mutant cardiomyocytes. Single-cell RNA-seq of cardiac tissues from patients with DCM with the LMNA mutation confirmed the dysregulated expression of TEAD1 target genes. Our results propose an intervention for transcriptional dysregulation as a potential treatment of LMNA-related DCM.

Cross-ancestry genome-wide analysis of atrial fibrillation unveils disease biology and enables cardioembolic risk prediction.

Atrial fibrillation (AF) is a common cardiac arrhythmia resulting in increased risk of stroke. Despite highly heritable etiology, our understanding of the genetic architecture of AF remains incomplete. Here we performed a genome-wide association study in the Japanese population comprising 9,826 cases among 150,272 individuals and identified East Asian-specific rare variants associated with AF. A cross-ancestry meta-analysis of >1 million individuals, including 77,690 cases, identified 35 new susceptibility loci. Transcriptome-wide association analysis identified IL6R as a putative causal gene, suggesting the involvement of immune responses. Integrative analysis with ChIP-seq data and functional assessment using human induced pluripotent stem cell-derived cardiomyocytes demonstrated ERRg as having a key role in the transcriptional regulation of AF-associated genes. A polygenic risk score derived from the cross-ancestry meta-analysis predicted increased risks of cardiovascular and stroke mortalities and segregated individuals with cardioembolic stroke in undiagnosed AF patients. Our results provide new biological and clinical insights into AF genetics and suggest their potential for clinical applications.

Hemoglobin Alpha Chain Variant Zara Associated With Familial Asymptomatic Hypoxemia.

Numerous hemoglobin (Hb) gene mutations have been identified, leading to a spectrum of phenotypes ranging from asymptomatic carrier states to complicated hemolytic anemias. We report a rare case of asymptomatic hypoxemia in a father and his teenage daughter both of whom were found to be carriers of Hb gene variant Zara. Workup for alternative cardiovascular causes of hypoxemia was unremarkable. Further sequencing of the alpha globin locus showed both individuals to be heterozygous for the Hb Zara c.274C>A (p.Leu92Ile) variant of unknown significance in the alpha2-globin gene. This is the first documented association of this Hb variant with familial asymptomatic hypoxemia, highlighting the importance of evaluating for hemoglobinopathies in patients with reduced oxygen saturation.

Heart Failure Pathogenesis Elucidation and New Treatment Method Development.

Heart failure (HF) is a leading cause of death worldwide. In Japan, the number of HF patients has increased with its aging population, resulting in "HF pandemic." HF is the final stage of various cardiovascular diseases, including valvular heart disease, ischemic heart disease, atrial fibrillation, and hypertension. Cardiac hypertrophy is a compensatory response to increased workload and maintains cardiac function. Pressure overload due to mechanical stress causes cardiac hypertrophy, whereas continuous cardiac stress reduces wall thickness and consequently causes HF. Understanding the molecular mechanisms underlying this process is crucial to elucidate HF pathophysiology. We demonstrated that ischemia and DNA damage are important in the progression of hypertrophy to HF. Genetic mutations associated with cardiomyopathy and prognosis has been identified. To realize precision medicines for HF, the underlying molecular mechanisms need to be elucidated. In this review, we introduce new paradigms for understanding HF pathophysiology discovered through basic research.

Cardiac fibroblasts regulate the development of heart failure via Htra3-TGF-ß-IGFBP7 axis.

Tissue fibrosis and organ dysfunction are hallmarks of age-related diseases including heart failure, but it remains elusive whether there is a common pathway to induce both events. Through single-cell RNA-seq, spatial transcriptomics, and genetic perturbation, we elucidate that high-temperature requirement A serine peptidase 3 (Htra3) is a critical regulator of cardiac fibrosis and heart failure by maintaining the identity of quiescent cardiac fibroblasts through degrading transforming growth factor-ß (TGF-ß). Pressure overload downregulates expression of Htra3 in cardiac fibroblasts and activated TGF-ß signaling, which induces not only cardiac fibrosis but also heart failure through DNA damage accumulation and secretory phenotype induction in failing cardiomyocytes. Overexpression of Htra3 in the heart inhibits TGF-ß signaling and ameliorates cardiac dysfunction after pressure overload. Htra3-regulated induction of spatio-temporal cardiac fibrosis and cardiomyocyte secretory phenotype are observed specifically in infarct regions after myocardial infarction. Integrative analyses of single-cardiomyocyte transcriptome and plasma proteome in human reveal that IGFBP7, which is a cytokine downstream of TGF-ß and secreted from failing cardiomyocytes, is the most predictable marker of advanced heart failure. These findings highlight the roles of cardiac fibroblasts in regulating cardiomyocyte homeostasis and cardiac fibrosis through the Htra3-TGF-ß-IGFBP7 pathway, which would be a therapeutic target for heart failure.

Highly efficient hole injection from Au electrode to fullerene-doped triphenylamine derivative layer.

Triphenylamine derivatives are superior hole-transport materials. For their application to high-functional organic semiconductor devices, efficient hole injection at the electrode/triphenylamine derivative interface is required. Herein, we report the design and evaluation of a Au/fullerene-doped α-phenyl-4'-[(4-methoxyphenyl)phenylamino]stilbene (TPA) buffer layer/TPA/Au layered device. It exhibits rectification conductivity, indicating that hole injection occurs more easily at the Au/fullerene-doped TPA interface than at the Au/TPA interface. The Richardson-Schottky analysis of the device reveals that the hole injection barrier (ΦB) at the Au/fullerene-doped TPA interface decreases to 0.021 eV upon using C70 as a dopant, and ΦB of Au/TPA is as large as 0.37 eV. The reduced ΦB of 0.021 eV satisfies the condition for ohmic contact at room temperature (ΦB [Formula: see text] 0.025 eV). Notably, C70 doping has a higher barrier-reduction effect than C60 doping. Furthermore, a noteworthy hole-injection mechanism, in which the ion-dipole interaction between TPA and fullerenes plays an important role in reducing the barrier height, is considered based on cyclic voltammetry. These results should facilitate the design of an electrode/organic semiconductor interface for realizing low-voltage driven organic devices.

Functional Evaluation of Human Bioengineered Cardiac Tissue Using iPS Cells Derived from a Patient with Lamin Variant Dilated Cardiomyopathy.

Dilated cardiomyopathy (DCM) is caused by various gene variants and characterized by systolic dysfunction. Lamin variants have been reported to have a poor prognosis. Medical and device therapies are not sufficient to improve the prognosis of DCM with the lamin variants. Recently, induced pluripotent stem (iPS) cells have been used for research on genetic disorders. However, few studies have evaluated the contractile function of cardiac tissue with lamin variants. The aim of this study was to elucidate the function of cardiac cell sheet tissue derived from patients with lamin variant DCM. iPS cells were generated from a patient with lamin A/C (LMNA) -mutant DCM (LMNA p.R225X mutation). After cardiac differentiation and purification, cardiac cell sheets that were fabricated through cultivation on a temperature-responsive culture dish were transferred to the surface of the fibrin gel, and the contractile force was measured. The contractile force and maximum contraction velocity, but not the maximum relaxation velocity, were significantly decreased in cardiac cell sheet tissue with the lamin variant. A qRT-PCR analysis revealed that mRNA expression of some contractile proteins, cardiac transcription factors, Ca2+-handling genes, and ion channels were downregulated in cardiac tissue with the lamin variant.Human iPS-derived bioengineered cardiac tissue with the LMNA p.R225X mutation has the functional properties of systolic dysfunction and may be a promising tissue model for understanding the underlying mechanisms of DCM.

Spatiotemporal transcriptome analysis reveals critical roles for mechano-sensing genes at the border zone in remodeling after myocardial infarction.

The underlying mechanisms of ventricular remodeling after myocardial infarction (MI) remain largely unknown. In this study, we performed an integrative analysis of spatial transcriptomics and single-nucleus RNA sequencing (snRNA-seq) in a murine MI model and found that mechanical stress-response genes are expressed at the border zone and play a critical role in left ventricular remodeling after MI. An integrative analysis of snRNA-seq and spatial transcriptome of the heart tissue after MI identified the unique cluster that appeared at the border zone in an early stage, highly expressing mechano-sensing genes, such as Csrp3. AAV9-mediated gene silencing and overexpression of Csrp3 demonstrated that upregulation of Csrp3 plays critical roles in preventing cardiac remodeling after MI by regulation of genes associated with mechano-sensing. Overall, our study not only provides an insight into spatiotemporal molecular changes after MI but also highlights that the mechano-sensing genes at the border zone act as adaptive regulators of left ventricular remodeling.