Dilated Heart Research Articles

Loss of GATAD1 in cardiomyocyte does not cause cardiomyopathy in mice.

GATA zinc finger domain containing 1 (GATAD1) is an as-yet uncharacterized zinc finger domain protein, which was initially identified as a histone 3 trimethylated at lysine 4 (H3K4me3) interactor. A recessive mutation in GATAD1 is associated with adult-onset dilated cardiomyopathy and heart failure, suggesting that GATAD1 is critical for maintaining normal cardiac structure and function. However, little is known as to the specific role of GATAD1 in cardiomyocytes. A mammalian Gatad1 knockout model has yet to be generated for investigating its specific role in the heart. To address this, we generated a Gatad1 cardiomyocyte-specific knockout (cKO) mouse model. Gatad1 cKO mutants exhibited normal cardiac function during the aging process up to 18 months of age. Unlike the abnormal nuclei shape observed in patients carrying GATAD1 mutations, the nuclei shape of cardiomyocytes remained unaffected by the loss of Gatad1. Furthermore, Gatad1 cKO mice responded normally to pressure overload induced by transverse aortic constriction (TAC) surgery. Together, these observations suggest that deletion of Gatad1 in cardiomyocytes does not induce cardiomyopathy during aging or affect the response to pressure overload stress in mice.

Abstract 4136169: Phenotypic clustering of right heart dilatation in pulmonary arterial hypertension

Introduction: Right ventricular (RV) and right atrial (RA) dilatation are important hallmarks of disease severity in patients with pulmonary arterial hypertension (PAH). To obtain more insights on the clinical significance of RA dilatation, we phenotypically characterized patients with right heart dilatation. Aim: Description of different RV/RA phenotypes in PAH Methods: 203 incident, treatment naïve PAH patients with cardiac magnetic resonance (CMR) imaging were included. Phenotypic clustering was based on RA and RV dilatation. Conform literature, RA dilatation was defined by a RA index maximal area >15 cm 2 /m 2 . RV dilatation was defined by an RVEDV/LVEDV ratio >1.3 and >2.4 for extreme dilatation. Results: Four phenotypic patient clusters were identified: no dilatation (n=48), RV dilatation (n=78), RV+RA dilatation (n=53) and extreme RV dilatation + RA dilatation (n=23), Figure 1A. To unravel the additive clinical value of RA dilatation, we mainly compared patients with RV dilatation and patients with RV+RA dilatation. Intriguingly, patients with RV+RA dilatation demonstrated lower 3- and 5-year survival rates (58% and 43% vs. 75% and 55%) (Figure 1B) and were less likely to reverse RV dilatation after treatment initiation than patients with RV dilatation only. Despite the consequences of RA dilatation, we could not identify an explanation for the difference in RA dilatation between both groups. No difference in afterload was observed, shown by comparable pulmonary vascular resistance (9.9 [6.8-13] WU vs. 10 [7.5-12.3] WU, p>0.05). RV function was similarly impaired (RV ejection fraction: 36±9% vs. 33±9%, p>0.05). End-diastolic elastance (0.73 [0.39-1.11] mmHg/mL vs. 0.58 [0.40-0.94] mmHg/mL, p>0.05) and severity of tricuspid regurgitation did not differ. Finally, diuretic use (40% vs. 40%, p>0.05), age (54±16 vs. 57±19 yrs, p>0.05), female gender (70% vs. 60%, p>0.05) and iPAH diagnoses was similar (69% vs. 59%, p>0.05). Conclusion: PAH-patients with both RA and RV dilatation have a worse clinical profile than patients with only RV dilatation. However, no clear trigger for RA dilatation was found and future mechanistic studies should unravel factors explaining these differences in right heart adaptation.

New targets and biomarkers for doxorubicin-induced cardiotoxicity in humans: implications drawn from toxicogenomic data and molecular modelling

The doxorubicin-induced cardiotoxicity continues to be a life-threatening adverse effect in the clinic. Doxorubicin-induced acute cardiotoxicity is reversible, whereas chronic cardiotoxicity is irreversible, leading to dilated cardiomyopathy and heart failure. The aim of this study was to identify the molecular mechanisms associated with doxorubicin metabolites in doxorubicin-induced chronic cardiotoxicity. For this purpose, literature searches and in silico toxicogenomic analyses were conducted using various tools, including the Comparative Toxicogenomic Database, GeneMANIA, Metascape, MIENTURNET, ChEA3, and AutoDock. Additionally, molecular dynamics simulations were performed for 500 ns using Schrödinger software to assess the stability and dynamics of the representative docked complexes. We observed that doxorubicin biotransformed into five metabolites in the human heart and identified 11 common genes related to doxorubicin, its metabolites, dilated cardiomyopathy, and heart failure. Our findings revealed that doxorubicin and its metabolites primarily exhibited binding affinity to the beta-1 adrenergic receptor and fatty acid synthase. Furthermore, we identified several key transcription factors, especially the Homeobox protein Nkx-2.6, and hsa-miR-183-3p associated with this cardiotoxicity. Finally, we observed that, in addition to doxorubicinol, 7-deoxidoxorubicinone, another metabolite of doxorubicin, may also contribute to this cardiotoxicity. These findings contribute to our understanding of the processes underlying doxorubicin-induced chronic cardiotoxicity.

Septins regulate heart contractility through modulation of cardiomyocyte store-operated calcium entry.

Highly regulated cardiomyocyte Ca 2+ fluxes drive heart contractions. Recent findings from multiple organisms demonstrate that the specific Ca 2+ transport mechanism known as store-operated Ca 2+ entry (SOCE) is essential in cardiomyocytes for proper heart function, and SOCE dysregulation results in cardiomyopathy. Mechanisms that regulate SOCE in cardiomyocytes are poorly understood. Here we tested the role of cytoskeletal septin proteins in cardiomyocyte SOCE regulation. Septins are essential SOCE modulators in other cell types, but septin functions in cardiomyocytes are nearly completely unexplored. We show using targeted genetics and intravital imaging of heart contractility in Drosophila that cardiomyocyte-specific depletion of septins 1, 2, and 4 results in heart dilation that phenocopies the effects of SOCE suppression. Heart dilation caused by septin 2 depletion was suppressed by SOCE upregulation, supporting the hypothesis that septin 2 is required in cardiomyocytes for sufficient SOCE function. A major function of SOCE is to support SERCA-dependent sarco/endoplasmic reticulum (S/ER) Ca 2+ stores, and augmenting S/ER store filling by SERCA overexpression also suppressed the septin 2 phenotype. We also ruled out several potential SOCE-independent septin functions, as septin 2 phenotypes were not due to septin function during development and septin 2 was not required for z-disk organization as defined by α-actinin labeling. These results demonstrate, for the first time, an essential role of septins in cardiomyocyte physiology and heart function that is due, at least in part, to septin regulation of SOCE function.

Peripheral blood immune cells distribution in biopsy-proven myocarditis: etiology and prognostic correlates

Abstract Background Myocarditis is an inflammatory disease of the myocardium with viral or immune-mediated/autoimmune etiology. Definite etiological diagnosis relays on endomyocardial biopsy (EMB). High titre anti-heart autoantibodies (AHA) define severe autoimmune forms. Virus-negative myocarditis may require immunosuppression (IS) to reduce progression to dilated cardiomyopathy, heart transplant or death. Prognostic stratification is incomplete and IS is not always efficacious. Animal and human studies suggest a pathogenetic role of immune cells, but little is known on their peripheral distribution or prognostic role. Purpose Characterize EMB-proven myocarditis patients’ peripheral blood to identify new non-invasive etiological and prognostic biomarkers. Methods Seventy-eight EMB-proven myocarditis patients and 9 healthy controls (HC) were enrolled according to the Declaration of Helsinki and written informed consent was collected for each participant. Peripheral blood mononuclear cells were purified by Ficoll stratification and immune cells distribution was evaluated by flow cytometry. Variables were analysed by Mann-Whitney or Kruskall-Wallis and Dunn post-hoc tests clustering patients according to clinical features, EMB and AHA results. Results Compared to HC (figure 1), plasmacytoid dendritic cells were reduced in myocarditis patients: with autoimmune/lymphocytic forms (p=0.0091); without extra cardiac autoimmune diseases (AD, p=0.0075); in those unresponsive to IS (p=0.0379) or never treated because of spontaneous healing (p=0.0015). Moreover, several immunophenotypical features discriminated myocarditis type/IS-response from HC. Viral forms were characterized by reduced CD94+ NK cells and CCR2 over-expression in intermediate monocytes (p=0.029, p=0.013). Autoimmune cases were defined by: higher CD62L+ NK cells when AHA negative (p=0.019); increased Th1 if not requiring IS (p=0.03); higher γδ-TCR+ Th17 and reduced Treg cells if without other AD (both p=0.04), or higher CD4+/IL17+ cells with concurrent AD (p=0.02) and AHA positivity (p=0.036). Moreover, ongoing IS treatment influenced peripheral cells distribution: whole blood cell counts were more frequently altered and total NK cells were reduced (p=0.007); treg cells were reduced in patients actively treated but unresponsive to IS (p=0.036). Conclusion Biopsy-proven myocarditis patients showed a skewed peripheral blood distribution of either innate or adaptive immune cells according to different histology, etiology (viral vs autoimmune) and response to IS in autoimmune forms, unveiling potential new non-invasive immunological biomarkers for myocarditis. Figure: Plasmacytoid dendritic cells (pDCs) percentage was assessed by flow-cytometry and data were showed by boxplots clustering myocarditis patients for etiology (A), EMB histological result (B), presence of extracardiac AD (C) or IS response (D). Data were analysed by Kruskall-Wallis (graph bottom) and Dunn post-hoc tests.

ND15, subunit of the electron transport chain protein-complex I, age-dependently worsens cardiac performance in Drosophila melanogaster

Abstract Introduction In the natural aging process of the heart, aside others, mitochondrial dysfunction is an essential driver for the development of reduced cardiac performance. Previous analysis of protein expression levels in cardiomyocytes of aged mice and have found aberrancies in subunits of the mitochondrial Complexes I – IV of the electron transport chain. Especially, the complex I subunit ND15 was highly downregulated. To elucidate the functional effects of this gene on the cardiac performance, we generated cardiomyocyte specific ND15 knock-downs in Drosophila melanogaster. Methods We generated Drosophila with heart-specific (+/+; Hand4.2-GAL4/UAS-ND15; tdtK/+) (ND15-KD)knockdown of ND15 using the UAS/GAL4 system. The flies' cardiomyocytes endogenously express tdTomato, facilitating fluorescence-based live imaging of the heart by high-resolution video fluorescence microscopy. The recorded data was processed using a R-Script, resulting in Results We compared wild type (WT) flies to ND15-KD flies at age 3 weeks(young) and 7 weeks(old). Knockdown of ND15 resulted in impaired cardiac function. Most parameters deteriorated in aged flies in comparison to young flies. The heart frequency was significantly reduced (WT:6 beats/s – KD:4 beats/s – p<0.0001) in the 7 weeks old group, end-diastolic diameter of the heart tube increased significantly in 3 weeks old ND15KD flies compared to controls(WT:65µm – KD:74µm p<0,0001), resulting in a dilated heart tube Interestingly enough, this dilation in ND15-KD disappeared in 7 weeks old flies. The fractional shortening was significantly decreased in young(WT:33,5% - KD:30% p<0,01) and deteriorated in old flies (WT:35% - KD:22% p<0,0001), indicating a reduced contraction capability. For both 3 weeks and 7 weeks old groups, the heart-rate adjusted interbeat interval variance (WT:22% -KD: 40% p<0,0001) as well as the time of no cardiac action (WT: 22% - KD: 35% p<0,0001) increased and showed significant irregularities. The duration of systole and diastole combined also exhibited arrhythmic patterns (WT:15% - KD:20.5% p<0,0001). A general arrhythmia index (AI) increased significantly (WT: 0.25 – KD:0.5 p<0,0001) These arrhythmia parameters emphasize the arrhythmogenic potential of the ND15-knockdown. The relative relaxation capabilities drastically worsened with age, displaying a diastolic dysfunction in the 7 weeks old group. At half-time relaxation, the WT was at 60% relaxation, ND15KD at 46%). Conclusion This study demonstrates that heart-specific deletion of ND15 results in a marked impairment of systolic and diastolic cardiac function in Drosophila accompanied by pro-arrhythmogenic actions. We could identify ND15 as a new mitochondrial molecular target for the maintenance of regular cardiac function and rhythmicity, especially with increasing age. Further mechanistic studies and translation to mammalian organisms are ongoing.

Multicentre, randomized, double-blind, prospective study on the effects of ImmunoAdSorptiOn on cardiac function in patients with Dilated CardioMyopathy (IASO-DCM): Rationale and design.

Pilot studies indicate that immunoadsorption with subsequent IgG substitution (IA/IgG) induces beneficial effects in patients with dilated cardiomyopathy (DCM) and heart failure. This placebo-controlled study investigates whether IA/IgG treatment enhances left ventricular (LV) systolic function as compared to a control group receiving pseudo-treatment. This multicentre, randomized, double-blind, parallel-group trial aims to include 200 patients with heart failure due to DCM (LV ejection fraction [LVEF] <40%) on optimized guideline-directed heart failure medication. Participants are randomly assigned in a 1:1 ratio to IA/IgG using protein-A columns, or to pseudo-immunoadsorption followed by an intravenous infusion without IgG. Follow-up visits take place by telephone after 1 and 3 months and at the study centres after 6, 12 and 24 months. The primary efficacy endpoint is the change in LVEF from baseline to 6 months determined by contrast echocardiography, analysed at a core lab. In addition, LV end-diastolic and end-systolic volumes will be analysed as secondary endpoints over the entire study period to assess whether IA/IgG affects LV remodelling. As main secondary outcome, a composite of all-cause death, cardiac resuscitation, hospitalization for heart failure, and need for cardiac surgery to improve myocardial pump function will be evaluated after 24 months. In addition, exploratory outcomes as well as safety endpoints related to the treatment will be assessed throughout the whole study period. IASO-DCM is a randomized study which will provide comprehensive insights into the effects of immunoadsorption with subsequent IgG substitution in patients with DCM.

Four-dimensional automated quantitative echocardiography assessment of right heart remodeling in patients with functional tricuspid regurgitation.

Functional tricuspid regurgitation (FTR) has a pathophysiological connection with right heart remodeling. Given the increasing focus on right atrial remodeling in recent years, a comprehensive study of all aspects of right heart remodeling is crucial for understanding the progression and treatment of FTR. In the scientific literature, there is a lack of comprehensive exploration of right atrial remodeling in patients with FTR, and no reports on the potential correlation between the degree of this remodeling and the severity of tricuspid regurgitation (TR) have been published. This study aimed to evaluate the relationship between right heart parameters measured by four-dimensional (4D) automated quantitative echocardiography and the severity of TR in patients with FTR. In this prospective case-control study, 100 patients diagnosed with FTR by echocardiography at The First Affiliated Hospital of Guangxi Medical University from February 2022 to March 2023 were prospectively and consecutively selected as the case group, comprising 50 patients with mild FTR and 50 patients with moderate or severe FTR. Additionally, 30 healthy participants served as the control group. Routine echocardiography was employed to obtain two-dimensional (2D) and three-dimensional (3D) images, which was followed by 4D automated quantitative echocardiograph assessment. Analysis of variance (ANOVA) or Kruskal-Wallis tests were used to compare differences between groups, Pearson correlation coefficient analysis was used to discern the relationship between parameters and TR volume, multivariate linear regression was used to identify factors associated with TR volume, and logistic regression was employed to predict the severity of FTR. The case group consisted of 50 patients with mild FTR (26 males, 52%; age range, 31-78 years; mean age ± SD: 58±11.4 years) and 50 patients with moderate-to-severe FTR (21 males, 42%; age range, 29-87 years; mean age ± SD: 60±13.0 years). Additionally, 30 healthy participants (13 males, 43%; age range, 19-81 years; mean age ± SD: 58±13.3 years) constituted the control group. Patients with moderate-to-severe FTR had significant right heart dilatation and functional decline. The TR volume was highly correlated with right atrium minimum volume (RAVmin; r=0.864; P<0.001), and linear regression showed that the RAVmin was independently correlated with the severity of TR in patients (β=0.820; P<0.001). There were several predictive variables that were significantly associated with increased FTR severity, including right atrial reservoir strain [RASr; odds ratio (OR) =0.702; 95% confidence interval (CI): 0.575-0.857; P=0.001], right atrial conduit strain (RAScd; OR =1.308; 95% CI: 1.098-1.558; P=0.003), and right atrial reservoir circumferential strain (RASr-c; OR =0.823; 95% CI: 0.684-0.990; P=0.04). 4D automated quantitative echocardiography allows for the dynamic assessment of right heart volume and function. To determine the development of FTR, RA dilation appears to be more significant than right ventricular dilation. The RASr, RAScd, and RASr-c are directly correlated with FTR severity.

Long-term follow-up of the TRED-HF trial: Implications for therapy in patients with dilated cardiomyopathy and heart failure remission.

In TRED-HF, 40% of patients with recovered dilated cardiomyopathy (DCM) relapsed in the short term after therapy withdrawal. This follow-up investigates the longer-term effects of therapy withdrawal. TRED-HF was a randomized trial investigating heart failure therapy withdrawal in patients with recovered DCM over 6 months. Those randomized to continue therapy subsequently withdrew treatment between 6 and 12 months. Participants were recommended to restart therapy post-trial and were followed until May 2023. Clinical outcomes are reported in a non-randomized fashion from enrolment and from the end of the trial. The primary outcome was relapse defined as ≥10% reduction in left ventricular ejection fraction to <50%, doubling in N-terminal pro-B-type natriuretic peptide to >400 ng/L, or clinical features of heart failure. From enrolment to the last follow-up (median 6 years, interquartile range 6-7), 33 of 51 patients (65%) relapsed. The 5-year relapse rate from enrolment was 61% (95% confidence interval [CI] 45-73) and from the end of the trial was 39% (95% CI 19-54). Of 20 patients who relapsed during the trial, nine had a recurrent relapse during follow-up. Thirteen relapsed for the first time after the trial; seven had restarted low intensity therapy, four had not restarted therapy and two did not have therapy withdrawn. The mean intensity of therapy was lower after the trial compared to enrolment (mean difference -6 [-8 to -4]; p < 0.001). One third of relapses during follow-up had identifiable triggers (arrhythmia [n = 4], pregnancy [n = 1], hypertension [n = 1], infection [n = 1]). Corrected atrial fibrillation was associated with reduced risk of relapse (hazard ratio 0.33, 95% CI 0.12-0.96; p = 0.042). The risk of relapse in the 5 years following the TRED-HF trial remained high. Restarting lower doses of heart failure medications at the end of the trial, external triggers and disease progression are likely to have contributed to relapse.

Identification of macrophage driver genes in fibrosis caused by different heart diseases based on omics integration

BackgroundMyocardial fibrosis, a hallmark of heart disease, is closely associated with macrophages, yet the genetic pathophysiology remains incompletely understood. In this study, we utilized integrated single-cell transcriptomics and bulk RNA-seq analysis to investigate the relationship between macrophages and myocardial fibrosis across omics integration.MethodsWe examined and curated existing single-cell data from dilated cardiomyopathy (DCM), ischemic cardiomyopathy (ICM), myocardial infarction (MI), and heart failure (HF), and analyzed the integrated data using cell communication, transcription factor identification, high dimensional weighted gene co-expression network analysis (hdWGCNA), and functional enrichment to elucidate the drivers of macrophage polarization and the macrophage-to-myofibroblast transition (MMT). Additionally, we assessed the accuracy of single-cell data from the perspective of driving factors, cell typing, anti-fibrosis performance of left ventricular assist device (LVAD). Candidate drugs were screened using L1000FWD.ResultsAll four heart diseases exhibit myocardial fibrosis, with only MI showing an increase in macrophage proportions. Macrophages participate in myocardial fibrosis through various fibrogenic molecules, especially evident in DCM and MI. Abnormal RNA metabolism and dysregulated transcription are significant drivers of macrophage-mediated fibrosis. Furthermore, profibrotic macrophages exhibit M1 polarization and increased MMT. In HF patients, those responding to LVAD therapy showed a significant decrease in driver gene expression, M1 polarization, and MMT. Drug repurposing identified cinobufagin as a potential therapeutic agent.ConclusionUsing integrated single-cell transcriptomics, we identified the drivers of macrophage-mediated myocardial fibrosis in four heart diseases and confirmed the therapeutic effect of LVAD on improving HF with single-cell accuracy, providing novel insights into the diagnosis and treatment of myocardial fibrosis.

Transcriptome sequencing analysis reveals the molecular regulatory mechanism of myocardial hypertrophy induced by angiotensin II

The pathogenesis of myocardial hypertrophy remains incompletely understood, highlighting the critical need for in-depth investigation into its pathogenesis and pathophysiology to develop innovative strategies for preventing and treating heart diseases. In this study, a model of angiotensin II (Ang II)-induced myocardial hypertrophy was established using subcutaneous administration with a micropump. Echocardiography, wheat germ agglutinin staining, and western blot analysis were used to evaluate the myocardial hypertrophy model after 5, 10, and 15 days of Ang II treatment. RNA-seq was employed to analyze the differential expression profile of mRNA, followed by bioinformatics analysis. Subsequently, the anti-inflammatory drug meloxicam was utilized to explore its impact on cardiac hypertrophy in mice. The findings demonstrated that mice developed myocardial hypertrophy following subcutaneous administration of Ang II. Transcriptomic analysis revealed significant changes in gene expression in the myocardium induced by Ang II, with the most pronounced differences observed at day 10. Functional analysis and verification of differentially expressed genes indicated that Ang II triggered an inflammatory response in the myocardium, leading to up-regulation of genes associated with fibrosis and apoptosis while decreasing energy metabolism; alterations were also observed in genes related to oxidative stress and calcium ion binding. Treatment with meloxicam improved Ang II-induced myocardial hypertrophy. This study not only elucidated the molecular regulatory mechanism underlying mouse myocardial hypertrophy at a transcriptional level but also provided new insights into clinical prevention and treatment strategies for cardiac diseases such as dilated cardiomyopathy and heart failure.

High-Output Heart Failure Secondary to Post-Traumatic Arteriovenous Fistula

Introduction: Arteriovenous fistulas are abnormal connections between the arterial and venous systems that bypass normal anatomical capillary beds. Any device, implement, or projectile that passes through an artery and vein has the potential to lead to one, thereby preventing normal blood flow through the capillary bed. Late complications of untreated arteriovenous fistulas include proximal arterial dilation, venous congestion, congestive heart failure, and distal ischemia. Objective: Describe the clinical manifestations, diagnostic, therapeutic, prognostic complexities and complications present in post-traumatic arteriovenous fistula and its association with heart failure. Material and methods: Retrospective study presentation of a clinical case. Results: The case of a 55-year-old female patient is presented, with a 2-year history of ischemic heart disease and a gunshot wound 20 years ago. Who was admitted for bypass and coronary angiography + cardiac angiography in whom no etiology of his dilated ischemic heart disease was found until Doppler ultrasound and tomography angiography was performed due to recurrence of pain in the lower limbs and changes in skin color, which revealed presence of arteriovenous fistula. The same one that was resolved with distal ligation of the popliteal vein + exclusion of aneurysm. Conclusions: Risk factors for the development of this pathology are difficult to establish. Therefore, the shotgun trauma to the left leg 20 years ago, in addition to her obesity and female sex, led to the formation of an arteriovenous fistula that would gradually produce high-grade heart failure. Endovascular AVF repair is a treatment alternative for those patients considered high risk from anesthesia, those who have a hostile groin due to excessive scar tissue, or who cannot tolerate the consequences of bleeding that can occur with surgical control. of the FAV.

Efficacy of mesenchymal stem cell transplantation on major adverse cardiovascular events and cardiac function indices in patients with chronic heart failure: a meta-analysis of randomized controlled trials

BackgroundThe effects of mesenchymal stem cells (MSCs) on heart failure (HF) have been controversial. This study was conducted to investigate whether the transplantation of MSCs after HF could help improve clinical outcomes and myocardial performance indices.MethodsUsing a systematic approach, electronic databases were searched for randomized controlled trials (RCTs), which evaluated the transplantation of MSCs after HF. The outcomes owf interest included clinical outcomes and myocardial function indices. We also assessed the role of age, cause of heart failure, cell origin, cell number, type of donor (autologous/allogeneic), and route of cell delivery on these outcomes. Using the random-effects method, a relative risk (RR) or mean difference (MD) and their corresponding 95% confidence intervals (CI) were pooled.ResultsSeventeen RCTs including 1684 patients (927 and 757 patients in the intervention and control arms, respectively) were enrolled. The RR (95% CI) of mortality was 0.78 (0.62; 0.99, p = 0.04) in the MSC group compared to the controls. HF rehospitalization decreased in the MSC group (RR = 0.85 (0.71–1.01), p = 0.06), but this was only significant in those who received autologous MSCs (RR = 0.67 (0.49; 0.90), p = 0.008). LVEF was significantly increased among those who received MSC (MD = 3.38 (1.89; 4.87), p < 0.001). LVESV (MD = −9.14 (−13.25; −5.03), p < 0.001), LVEDV (MD = −8.34 −13.41; −3.27), p < 0.001), and scar size (standardized MD = -0.32 (-0.60; -0.05), p = 0.02) were significantly decreased. NYHA class (MD = −0.19 (−0.34; −0.06), p = 0.006), BNP level (standardized MD = −0.28 (−0.50; −0.06), p = 0.01), and MLHFQ (MD = −11.55 (−16.77; −6.33), p = 0.005) significantly decreased and 6-min walk test significantly improved (MD = 36.86 (11.22; 62.50), p = 0.001) in the MSC group. Trials were not affected by the participants’ etiology of heart failure, while trials with the autologous source of cells, MSC doses lower than 100 million cells, and intracoronary injection performed significantly better in some of the outcomes.ConclusionTransplantation of MSCs for ischemic or dilated heart failure patients may reduce all-cause mortality and improve clinical condition. Moreover, this treatment would improve left ventricular function indices and reduce scar size.Graphical

Obstetric anesthesia management of dilated cardiomyopathies and heart failure: a narrative review

Pregnancy in patients with dilated cardiomyopathy carries a significantly increased risk of maternal mortality or severe morbidity, and pregnancy is typically considered contraindicated for patients with severely reduced ventricular function. Nonetheless, anesthesiologists will still encounter patients with cardiomyopathy requiring delivery or termination care. This review describes how NT-ProBNP testing and echocardiography can help with early recognition of heart failure in pregnancy, and describes a suggested approach to anesthetic management of patients with cardiomyopathies or acute heart failure, including hemodynamic goals, use of vasoactive medications and mechanical support. Vaginal delivery, with effective neuraxial anesthesia is the preferred mode of delivery in most patients with cardiomyopathy, with cesarean delivery reserved for maternal or fetal indications. The Pregnancy Heart Team is vital in coordinating the multidisciplinary care necessary to safely support these patients through pregnancy.

Abstract Mo042: Poison Peptides May Contribute to Dysregulation of SERCA in Heart Failure

Proteolysis increases in heart disease, resulting in an accumulation of degraded membrane protein fragments in heart cells. Previous studies have shown that diverse hydrophobic alpha helices can bind and non-specifically inhibit the cardiac calcium pump SERCA. Thus, we hypothesized that partially degraded fragments of transmembrane proteins may directly inhibit SERCA or compete with native peptide regulators of the pump, like such as phospholamban. The resulting dysregulation of SERCA may contribute to calcium mishandling in heart failure. To test these hypotheses, purified cell membranes from non-failing or dilated cardiomyopathy human hearts were subjected to SDS-PAGE and mass spectrometry to identify protein fragments smaller than 26 kD. 1800 proteins were detected, of which 92 were upregulated &gt;3 fold in the failing heart samples, consistent with increased production of small fragments from these membrane proteins. 9 of the upregulated fragments containing transmembrane segments were selected for further analysis based on sequence hydrophobicity and structural similarity to endogenous micropeptide regulators of SERCA. Of these 9 fragments, 6 showed ER localization, suggesting potential for a toxic interaction with SERCA. The relative binding of these candidates to SERCA was quantified with FRET microscopy. Fragments of three membrane proteins (SEC61B, VAMP3, VAMP8) showed an avid interaction with SERCA. To measure SERCA inhibition, we utilized a calcium activity assay was performed usingin which HEK293T cells were transfected with SERCA, ryanodine receptor, candidate peptides and rCepia as an ER calcium indicator. ER-calcium level was normalized to minimum fluorescence after caffeine addition and an ionomycin induced maximum fluorescence after addition of ionomycin and calcium and caffeine induced minimum. Unregulated Candidate poison peptides were compared to SERCA alone and SERCA-PLB phospholamban controls were also performed. . SEC61B demonstrated the a strongest inhibition, most (similar to phospholamban, ) while VAMP3 and VAMP8’s effect was more modest. This type of non-nativeThus, we propose accumulation of toxic transmembrane peptide fragments may inhibition could be contributinginhibit SERCA and contribute to the calcium mishandling seen in heart failure. Future experiments will be performed to quantify the relative abundance of the fragments compared to endogenous regulatory micropeptides.

Abstract Mo014: Cardioactive molecules identified by functional in vivo screening prevent anthracycline cardiotoxicity

Introduction: Promotion of cardiomyocyte survival upon insult is mandatory to allow maintenance of ventricular function and dam development of severe heart dysfunction. Recently, through an in vivo functional screening of the mouse secretome we identified potent mediators of cardiomyocyte survival among 1200 soluble factors expressed by AAV vectors. The cardiac overexpression of the most effective cytokines (Chrdl1, Fam3c and Fam3b) maintained cardiac function after myocardial infarction by blunting oxidative damage, decreasing cell death, promoting autophagy, and inhibiting myofibroblast activation (Ruozi, Bortolotti et al. 2022. Sci Transl Med 14, eabo0699) Aim: We investigated the effect of cardioactive proteins in a mouse anthracycline model of cardiotoxicity. Material and Methods: Mimicking clinical chronic therapeutic regimens, doxorubicin (24 mg/kg) was administered to C57/BL6 female mice one week after AAV9-driven cardiac overexpression of Chrdl1, Fam3b or Fam3c. Echocardiography was performed after 6 and 8 weeks and was followed by histology and molecular analysis. Apoptosis, autophagy and mitochondrial function was analysed in primary cardiomyocytes along with pathway investigation. Results: AAV9-mediated overexpression of Chrdl1, Fam3b and Fam3c markedly improved animal survival. Echocardiographic assessment revealed significant reduction of left ventricular ejection fraction and marked heart dilatation in control animals, while all treated animals maintained functional and anatomical parameters. Treated mice showed normal cardiac mass and cardiomyocyte cross-sectional area, reduced interstitial collagen deposition and decreased expression of profibrotic genes. In both rodents and human cardiomyocytes, Chrdl1, Fam3b and Fam3c factors decreased doxorubicin induced apoptosis, induced protective macroautophagy and preserved mitochondrial morphology. Chrdl1 prevented doxorubicin-mediated BMP upregulation and autophagy engulfment through the inhibition of a detrimental molecular pathway downstream the BMP receptor. Conclusions: The development of biotherapeutics that act as pro-survival factors for cardiomyocytes offers significant translational perspectives in cardio-oncology.

Ubiquitin Ligase RBX2/SAG Regulates Mitochondrial Ubiquitination and Mitophagy.

Clearance of damaged mitochondria via mitophagy is crucial for cellular homeostasis. Apart from Parkin, little is known about additional Ub (ubiquitin) ligases that mediate mitochondrial ubiquitination and turnover, particularly in highly metabolically active organs such as the heart. In this study, we have combined in silico analysis and biochemical assay to identify CRL (cullin-RING ligase) 5 as a mitochondrial Ub ligase. We generated cardiomyocytes and mice lacking RBX2 (RING-box protein 2; also known as SAG [sensitive to apoptosis gene]), a catalytic subunit of CRL5, to understand the effects of RBX2 depletion on mitochondrial ubiquitination, mitophagy, and cardiac function. We also performed proteomics analysis and RNA-sequencing analysis to define the impact of loss of RBX2 on the proteome and transcriptome. RBX2 and CUL (cullin) 5, 2 core components of CRL5, localize to mitochondria. Depletion of RBX2 inhibited mitochondrial ubiquitination and turnover, impaired mitochondrial membrane potential and respiration, increased cardiomyocyte cell death, and has a global impact on the mitochondrial proteome. In vivo, deletion of the Rbx2 gene in adult mouse hearts suppressed mitophagic activity, provoked accumulation of damaged mitochondria in the myocardium, and disrupted myocardial metabolism, leading to the rapid development of dilated cardiomyopathy and heart failure. Similarly, ablation of RBX2 in the developing heart resulted in dilated cardiomyopathy and heart failure. The action of RBX2 in mitochondria is not dependent on Parkin, and Parkin gene deletion had no impact on the onset and progression of cardiomyopathy in RBX2-deficient hearts. Furthermore, RBX2 controls the stability of PINK1 (PTEN-induced kinase 1) in mitochondria. These findings identify RBX2-CRL5 as a mitochondrial Ub ligase that regulates mitophagy and cardiac homeostasis in a Parkin-independent, PINK1-dependent manner.

Measurement of left ventricular volume with admittance incorporated onto percutaneous ventricular assist device.

Percutaneous ventricular assist devices (pVADs) incorporated with admittance electrodes have been validated in animal studies for accurate instantaneous volumetric measurements. Since miniaturization of the pVAD profile is a priority to reduce vascular complications in patients, our study aimed to validate admittance measurements using three electrodes instead of the standard four. Complex admittance was measured between an electrode pair and a pVAD metallic blood-intake tip, both with finite element analysis and on the benchtop. The catheter and electrode arrays were first simulated inside prolate ellipsoid models of the left ventricle (LV) demonstrating current flow throughout all parts of the LV as well as minimal influence of off-center catheter placement in the recorded signal. Admittance measurements were validated in 3D-printed models of healthy and dilated hearts (100-400mL end-diastolic volumes). Minimal interference between a pVAD motor and the current signal of our admittance system was demonstrated. A modified Wei's equation focused on three electrodes was developed to be compatible with reduced profile pVADs occurring clinically, incorporated with admittance electrodes and wires. The modified equation was compared against Wei's original equation showing improved accuracy of calculated volumes. Reducing electrode footprint can simplify the incorporation of Admittance technology on any pVAD, allowing for instantaneous recognition of native heart recovery and assistance with pVAD weaning.

The Ubiquitin Ligase RBX2/SAG Regulates Mitochondrial Ubiquitination and Mitophagy.

Clearance of damaged mitochondria via mitophagy is crucial for cellular homeostasis. While the role of ubiquitin (Ub) ligase PARKIN in mitophagy has been extensively studied, increasing evidence suggests the existence of PARKIN-independent mitophagy in highly metabolically active organs such as the heart. Here, we identify a crucial role for Cullin-RING Ub ligase 5 (CRL5) in basal mitochondrial turnover in cardiomyocytes. CRL5 is a multi-subunit Ub ligase comprised by the catalytic RING box protein RBX2 (also known as SAG), scaffold protein Cullin 5 (CUL5), and a substrate-recognizing receptor. Analysis of the mitochondrial outer membrane-interacting proteome uncovered a robust association of CRLs with mitochondria. Subcellular fractionation, immunostaining, and immunogold electron microscopy established that RBX2 and Cul5, two core components of CRL5, localizes to mitochondria. Depletion of RBX2 inhibited mitochondrial ubiquitination and turnover, impaired mitochondrial membrane potential and respiration, and increased cell death in cardiomyocytes. In vivo , deletion of the Rbx2 gene in adult mouse hearts suppressed mitophagic activity, provoked accumulation of damaged mitochondria in the myocardium, and disrupted myocardial metabolism, leading to rapid development of dilated cardiomyopathy and heart failure. Similarly, ablation of RBX2 in the developing heart resulted in dilated cardiomyopathy and heart failure. Notably, the action of RBX2 in mitochondria is not dependent on PARKIN, and PARKIN gene deletion had no impact on the onset and progression of cardiomyopathy in RBX2-deficient hearts. Furthermore, RBX2 controls the stability of PINK1 in mitochondria. Proteomics and biochemical analyses further revealed a global impact of RBX2 deficiency on the mitochondrial proteome and identified several mitochondrial proteins as its putative substrates. These findings identify RBX2-CRL5 as a mitochondrial Ub ligase that controls mitophagy under physiological conditions in a PARKIN-independent, PINK1-dependent manner, thereby regulating cardiac homeostasis.

Overexpression of ATP5F1A in Cardiomyocytes Promotes Cardiac Reverse Remodeling.

The mechanism of cardiac reverse remodeling (CRR) mediated by the left ventricular assist device remains unclear. This study aims to identify the specific cell type responsible for CRR and develop the therapeutic target that promotes CRR. The nuclei were extracted from the left ventricular tissue of 4 normal controls, 4 CRR patients, and 4 no cardiac reverse remodeling patients and then subjected to single-nucleus RNA sequencing for identifying key cell types responsible for CRR. Gene overexpression in transverse aortic constriction and dilated cardiomyopathy heart failure mouse model (C57BL/6J background) and pathological staining were performed to validate the results of single-nucleus RNA sequencing. Ten cell types were identified among 126 156 nuclei. Cardiomyocytes in CRR patients expressed higher levels of ATP5F1A than the other 2 groups. The macrophages in CRR patients expressed more anti-inflammatory genes and functioned in angiogenesis. Endothelial cells that elevated in no cardiac reverse remodeling patients were involved in the inflammatory response. Echocardiography showed that overexpressing ATP5F1A through cardiomyocyte-specific adeno-associated virus 9 demonstrated an ability to improve heart function and morphology. Pathological staining showed that overexpressing ATP5F1A could reduce fibrosis and cardiomyocyte size in the heart failure mouse model. The present results of single-nucleus RNA sequencing and heart failure mouse model indicated that ATP5F1A could mediate CRR and supported the development of therapeutics for overexpressing ATP5F1A in promoting CRR.