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Phospholamban (PLN) plays a crucial role in regulating sarcoplasmic reticulum (SR) Ca 2+ cycling and cardiac contractility. Mutations within the PLN gene have been detected in patients with cardiomyopathy, with the heterozygous variant c.40_42delAGA (p.R14del) of PLN being the most prevalent. Investigations into the mechanisms underlying the pathology of PLN-R14del have revealed that cardiac cells from affected patients exhibit pathological aggregates containing PLN. Herein, we performed comprehensive molecular and cellular analyses to delineate the molecular aberrations associated with the formation of these aggregates. We determined that PLN aggregates contain autophagic proteins, indicating inefficient degradation via the autophagy pathway. Our findings demonstrate that the expression of PLN-R14del results in diminished autophagic flux due to impaired fusion between autophagosomes and lysosomes. Mechanistically, this defect is linked to aberrant recruitment of key membrane fusion proteins to autophagosomes, which is mediated in part by changes in Ca 2+ homeostasis. Collectively, these results highlight a novel function of PLN-R14del in regulating autophagy, that may contribute to the formation of pathogenic aggregates in patients with cardiomyopathy. Prospective strategies tailored to ameliorate impaired autophagy may hold promise against PLN-R14del disease., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication All authors agree to the publication of this study. Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest. A.G.E is co-founder and CSO of GENOSOPHY, a spin-off company of the National and Kapodistrian University of Athens., (© 2024. The Author(s).)

Aim: Mitochondrial dysfunction is a critical factor in the pathogenesis of septic cardiomyopathy (SCM). Mitochondrial anchored protein ligase (MAPL), a small ubiquitin-like modifier (SUMO) E3 ligase, plays a significant role in mitochondrial function. However, the role of MAPL in SCM remains unclear., Methods: To investigate the role of MAPL in SCM, cardiomyocyte-specific MAPL knockout mice were generated. A cecal ligation and puncture (CLP) procedure was employed to induce a sepsis-like condition., Results: The expression of MAPL in heart tissues and H9C2 cardiomyocytes was elevated following CLP challenge or lipopolysaccharide (LPS) stimulation. MAPL deficiency ameliorated CLP-induced cardiac injury, dysfunction, and inflammation, and also improved the survival rate of mice following CLP operation. Additionally, MAPL deficiency or knockdown inhibited LPS-induced cardiomyocyte apoptosis, improved mitochondrial structural abnormalities, and increased ATP production. Furthermore, MAPL knockdown mitigated LPS-induced reductions in mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) production. Mechanistically, the expression of dynamin-related protein 1 (drp1) in the mitochondria of heart tissues or H9C2 cardiomyocytes was elevated under septic conditions. Accordingly, the SUMOylation of drp1 in heart tissues or H9C2 cardiomyocytes was increased under sepsis conditions, which was reduced by MAPL knockout or knockdown., Conclusion: Our results reveal that MAPL promotes cardiac injury/dysfunction and inflammation in SCM. Deficiency or knockdown of MAPL alleviates SCM by reducing drp1 SUMOylation as well as drp1-mediated mitochondrial dysfunction. These findings suggest that targeting MAPL may represent a therapeutic strategy for patients with SCM., Competing Interests: Declarations Consent for publication All authors concur with the submission and publication of this paper. Conflict of interest The authors have no relevant financial or non-financial interests to disclose., (© 2024. The Author(s).)

Aims: Fetal alcohol spectrum disorders (FASDs) impact up to 0.8% of the global population. However, cardiovascular health outcomes in adult patients, along with predictive biomarkers for cardiac risk stratification, remain unknown. Our aim was to utilize a longitudinal cohort study in an animal model to evaluate the impact of embryonic alcohol exposure (EAE) on cardiac structure, function, and transcriptional profile across the lifespan., Methods and Results: Using zebrafish, we characterized the aftereffects of EAE in adults binned by congenital heart defect (CHD) severity. Chamber sizes were quantified on dissected adult hearts to identify structural changes indicative of cardiomyopathy. Using echocardiography, we quantified systolic function based on ejection fraction and longitudinal strain, and diastolic function based on ventricular filling dynamics, ventricular wall movement, and estimated atrial pressures. Finally, we performed RNA-sequencing on EAE ventricles and assessed how differentially expressed genes (DEGs) correlated with cardiac function. Here, we demonstrate that EAE causes cardiomyopathy and diastolic dysfunction through persistent alterations to ventricular wall structure and gene expression. Following abnormal ventricular morphogenesis, >30% of all EAE adults developed increased atrial-to-ventricular size ratios, abnormal ventricular filling dynamics, and reduced myocardial wall relaxation during early diastole despite preserved systolic function. RNA-sequencing of the EAE ventricle revealed novel and heart failure-associated genes (slc25a33, ankrd9, dusp2, dusp4, spry4, eya4, and edn1) whose expression levels were altered across the animal's lifespan or correlated with the degree of diastolic dysfunction detected in adulthood., Conclusion: Our study identifies EAE as a risk factor for adult-onset cardiomyopathy and diastolic dysfunction, regardless of CHD status, and suggests novel molecular indicators of adult EAE-induced heart disease., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Desmin is a type III intermediate filament protein specifically expressed in muscle cells, which is encoded by the DES gene. Defects in the desmin protein and cytoskeletal instability may interfere with cardiac muscle conduction signals, a fundamental mechanism for arrhythmias in patients with desmin-related myopathy. This current case report presents a female patient in her early 20s who presented with early-onset complete atrioventricular block and complete left bundle branch block over the previous decade. More recently, she had developed ventricular tachycardia, ventricular fibrillation, atrial fibrillation and other arrhythmias. Echocardiography revealed non-compaction of the ventricular myocardium and pulmonary hypertension. Whole-exome sequencing analysis identified a heterozygous missense mutation in the DES gene: c.1216C>T (p.Arg406Trp). She was eventually diagnosed with arrhythmias due to desmin-related myopathy. A literature review of international databases was undertaken to summarise the clinical characteristics of the cardiac involvement associated with this DES gene mutation., Competing Interests: Declaration of conflicting interestThe authors declare that there are no conflicts of interest.

Myocardial fibrosis is a common endpoint of many cardiac diseases and increasingly recognized as a predictor of heart failure, arrhythmia, and death. Recent studies have utilised cardiac computed tomography (CT) scans with delayed phase imaging to quantify diffuse fibrosis of the myocardium. CT extracellular volume (CT-ECV) measurement correlates well with CMR and histological myocardial fibrosis. Furthermore, CT-ECV predicts outcomes such as death, heart failure and arrhythmia in various disease states. This review summarizes the rationale and methodology behind CT-ECV measurement and provides a detailed summary of the current clinical evidence for the use of CT-ECV., Competing Interests: Declarations Disclosures S.J.N. has received research support from AstraZeneca, Amgen, Anthera, CSL Behring, Cerenis, Eli Lilly, Esperion, Resverlogix, Novartis, InfraReDx and Sanofi-Regeneron and is a consultant for Amgen, Akcea, AstraZeneca, Boehringer Ingelheim, CSL Behring, Eli Lilly, Esperion, Kowa, Merck, Takeda, Pfizer, Sanofi- Regeneron, CSL Sequiris, Cyclarity, Vaxxinity and Novo Nordisk. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Becker muscular dystrophy (BMD) is an X-linked disorder due to in-frame mutations in the DMD gene, leading to a less abundant and truncated dystrophin. BMD is less common and severe than Duchenne muscular dystrophy (DMD) as well as less investigated. To accelerate the search for innovative treatments, we developed a rat model of BMD by deleting the exons 45-47 of the Dmd gene. Here, we report a functional and histopathological evaluation of these rats during their first year of life, compared to DMD and control littermates. BMD rats exhibit moderate damage to locomotor and diaphragmatic muscles but suffer from a progressive cardiomyopathy. Single nuclei RNA-seq analysis of cardiac samples revealed shared transcriptomic abnormalities in BMD and DMD rats and highlighted an altered end-addressing of TMEM65 and Connexin-43 at the intercalated disc, along with electrocardiographic abnormalities. Our study documents the natural history of a translational preclinical model of BMD and reports a cellular mechanism for the cardiac dysfunction in BMD and DMD offering opportunities to further investigate the organization role of dystrophin in intercellular communication., (© 2024. The Author(s).)

The tumor protein D52 (TPD52) gene encodes a proto-oncogene protein associated with various medical conditions, including breast and prostate cancers. It plays a role in multiple biological pathways such as cell growth, differentiation, and apoptosis. The function of TPD52 in lipid droplet biosynthesis has been investigated in vitro. However, its precise role in lipid metabolism in animal models is not fully understood. To investigate the functions of TPD52 in vivo, we performed a conditional TPD52 protein expression analysis using a Tet-off transgenic system to establish conditionally expressed Tpd52 transgenic zebrafish. The effect of Tpd52 on lipogenesis was assessed using various methods, including whole-mount Oil Red O staining, histological examination, and measurement of inflammatory markers and potential targets using real-time quantitative polymerase chain reaction and immunoblotting in Tpd52 fish. Zebrafish with increased Tpd52 levels exhibited notable weight gain and the enlargement of fat deposits, which were mainly attributed to an increase in the volume of adipocytes. Moreover, Tpd52 overexpression was correlated with the triggering of the adipocyte differentiation signaling pathway. During adipocytic differentiation in response to nutrient status, our observations revealed adipogenesis, nonalcoholic fatty liver disease, and metabolic cardiomyopathy (MCM) in Tpd52 transgenic zebrafish. To gain a deeper understanding of the contribution of these proteins to the regulation of cellular growth, we investigated the expression of their corresponding genes and proteins in zebrafish. In the present study, the activated protein kinase pathway was identified as the primary target of TPD52. Adult Tpd52 zebrafish showed increased lipid accumulation, resulting in the development of visceral obesity, nonalcoholic fatty liver disease, and MCM. These findings strongly suggest that TPD52 actively contributes to adipose tissue expansion and its subsequent effects. This investigation provides compelling evidence that Tpd52 facilitates adipocyte development and related metabolic comorbidities in zebrafish., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Uremic cardiomyopathy (UC) represents a complex syndrome characterized by different cardiac complications, including systolic and diastolic dysfunction, left ventricular hypertrophy, and diffuse fibrosis, potentially culminating in myocardial infarction (MI). Revascularization procedures are often necessary for MI management and can induce ischemia reperfusion injury (IR). Despite this clinical relevance, the role of fine particulate matter (PM 2.5 ) in UC pathology and the underlying subcellular mechanisms governing this pathology remains poorly understood. Hence, we investigate the impact of PM 2.5 exposure on UC susceptibility to IR injury. Using a rat model of adenine-induced chronic kidney disease (CKD), the animals were exposed to PM 2.5 at 250 µg/m 3 for 3 h daily over 21 days. Subsequently, hearts were isolated and subjected to 30 min of ischemia followed by 60 min of reperfusion to induce IR injury. UC hearts exposed to PM 2.5 followed by IR induction (Adenine + PM_IR) exhibited significantly impaired cardiac function and increased cardiac injury (increased infarct size and apoptosis). Analysis at the subcellular level revealed reduced mitochondrial copy number, impaired mitochondrial bioenergetics, decreased expression of PGC1-α (a key regulator of mitochondrial biogenesis), and compromised mitochondrial quality control mechanisms. Additionally, increased mitochondrial oxidative stress and perturbation of the PI3K/AKT/AMPK signaling axis were evident. Our findings therefore collectively indicate that UC myocardium when exposed to PM 2.5 is more vulnerable to IR-induced injury, primarily due to severe mitochondrial impairment., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Sepsis is a life-threatening severe inflammatory reaction caused by the host's dysregulated response to infection. Sepsis-induced myocardial dysfunction (SIMD) has been confirmed to occur in 50 % of patients with septic shock. Currently, the pathophysiological mechanism of SIMD is complex, and there is no targeted treatment. Elabela is another endogenous ligand of Aplnr (APJ). The protective effect of APJ on the heart has been proven. Elabela (Ela) has been shown to have a variety of cardiovascular protective effects. However, there are no studies demonstrating the protective effect of Ela-APJ axis on SIMD., Materials and Methods: In vivo, C57BL/J mice were injected subcutaneously with 1 mg/kg/d Ela for 2 weeks, and in vitro, AC16 cells were treated with 1 μM Ela for 24 h. A 7-0 thread was used to ligate the distal end of the cecum, followed by puncture with a 20-gauge needle. Once a small amount of fluid leaks out, release the cecum back into the abdominal cavity. We measured the survival rates of the mice, performed ultrasound on their hearts, and evaluated the effects of the treatments. The serum and cell supernatant were extracted to detect myocardial injury markers and pyroptosis-related indicators. Western blotting was used to detect autophagy and pyroptosis-related protein. Molecular docking and other experiments were also used to detect changes in related proteins., Results: In vivo, Ela significantly improved the survival rate of septic mice, improved cardiac function, and reduced the production of myocardial injury markers, oxidative stress and pyroptosis. In vitro, Ela unblocked autophagy flow by affecting TFEB transcription. Autophagy reduces inflammation and oxidative stress by selectively degrading inflammatory bodies and ultimately alleviates pyroptosis., Conclusion: We had demonstrated for the first time that in sepsis, Ela promoted the degradation of inflammasomes, reduced oxidative stress, and inhibited the occurrence of pyroptosis by unblocking autophagy flow., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Sepsis is a systemic inflammatory disease that can cause multiple organ damage. Septic patients with cardiac dysfunction have a significantly higher mortality. Based on the results of bioinformatics analysis, weighted gene co-expression network analysis (WGCNA), we found that Erbin is vital in cardiomyocyte. However, the function of Erbin in sepsis-induced cardiomyopathy (SIC) has not been explicitly studied. We discussed the role of Erbin in SIC by employing the Erbin -/- mice and HL-1 cardiomyocyte. An in vitro model of inflammation in HL-1 was used to confirm stimulation with lipopolysaccharide (LPS) and a mouse model of cecal ligation and puncture (CLP) to study the molecular mechanisms under SIC. Transmission electron microscopy (TEM) was used to characterize the morphological characteristics at the ultrastructural level. The expressions of Erbin, p-RIPK1, RIPK1, p-RIPK3, RIPK3, p-MLKL, MLKL, p-PKA, PKA, p-CREB and CREB were detected by western blot. qPCR analysis was applied to detect TNF-α, IL-1β, IL-6, RIPK1 and MLKL mRNA expression. Cell survival was detected by CCK-8 assay and the levels of c TnI concentration were detected by ELISA kit. Our study revealed that necroptosis and inflammation were activated in cardiomyocytes during sepsis and deficiency of Erbin aggravated them. Furthermore, deficiency of Erbin exacerbated systolic dysfunction including the decline of LVEF and LVFS induced by CLP. Overexpression of Erbin alleviated necroptosis and inflammation by activating PKA/CREB pathway. Our research elucidates a noval mechanism whereby Erbin participates in SIC, providing a promising therapeutic target for myocardial dysfunction during sepsis., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024. Published by Elsevier Inc.)

In this study, by pooling the clinical data of patients who died with a history of long-term clozapine use and by examining their hearts, it was found that long-term clozapine use can lead to cardiomyopathy and that its presentation resembles arrhythmogenic cardiomyopathy (ACM), i.e., it exhibits a predominantly right ventricular fatty infiltration with mild left ventricular damage. The transcriptomic data of rat cardiomyocytes after clozapine intervention were analyzed by transcriptomic approach to explore the causes of clozapine cardiomyopathy. The cause of clozapine cardiomyopathy was then explored by a transcriptomic approach, which revealed that its clozapine action on cardiomyocytes enriched cardiomyocyte-related differential genes in biological processes such as muscle development and response to hypoxia, as well as pathways such as fatty acid metabolism and cellular autophagy. Transcriptomic analysis showed that Egr1, Egr2, ler2, Jun, Mapk9, Nr1d2, Atf3, Bhlhe40, Crem, Cry1, Cry2, Dbp were hub genes for clozapine injury to the myocardium, and that these genes may play an important role in the myocardial ACM-like changes caused by clozapine. Combined with the results of pathological examination and transcriptomic analysis, it can be concluded that the long-term action of clozapine on cardiomyocytes leads to cellular autophagy and subsequent structural remodeling of the heart, and in the remodeling affects fatty acid metabolism, which eventually leads to ACM-like changes., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Over the years, advancements in the field of oncology have made remarkable strides in enhancing the efficacy of medical care for patients with cancer. These modernizations have resulted in prolonged survival and improved the quality of life for these patients. However, this progress has also been accompanied by escalation in mortality rates associated with anthracycline chemotherapy. Anthracyclines, which are known for their potent antitumor properties, are notorious for their substantial cardiotoxic potential. Remarkably, even after 6 decades of research, a conclusive solution to protect the cardiovascular system against doxorubicin-induced damage has not yet been established. A comprehensive understanding of the pathophysiological processes driving cardiotoxicity combined with targeted research is crucial for developing innovative cardioprotective strategies. This review seeks to explain the mechanisms responsible for structural and functional alterations in doxorubicin-induced cardiomyopathy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Background: In systemic light-chain (AL) amyloidosis, cardiac involvement portends poor outcomes., Objectives: The authors' objectives were to detect early myocardial alterations, to analyze longitudinal changes with therapy, and to predict major adverse cardiac events (MACE) in participants with AL amyloidosis using cardiac magnetic resonance imaging (MRI)., Methods: Recently diagnosed participants were prospectively enrolled. AL amyloidosis with and without cardiomyopathy (AL-CMP, AL-non-CMP) were defined based on abnormal cardiac biomarkers and wall thickness. MRI was performed at baseline, 6 months in all participants, and 12 months in participants with AL-CMP. MACE were defined as all-cause death, heart failure hospitalization, and cardiac transplantation. Mayo stage was based on troponin T, N-terminal pro-B-type natriuretic peptide, and difference in free light chains., Results: This study included 80 participants (median age 62 years, 58% men). Extracellular volume (ECV) was abnormal (>32%) in all participants with AL-CMP and in 47% of those with AL-non-CMP. ECV tended to increase at 6 months (median +2%; AL-CMP P = 0.120; AL-non-CMP P = 0.018) and returned to baseline values at 12 months in participants with AL-CMP. Global longitudinal strain (GLS) improved at 6 months (median -0.6%; P = 0.048) and 12 months (median -1.2%; P < 0.001) in participants with AL-CMP. ECV and GLS were strongly associated with MACE (P < 0.001) and improved the prognostic value when added to Mayo stage (P ≤ 0.002). No participant with ECV ≤32% had MACE, while 74% of those with ECV >48% had MACE., Conclusions: In patients with systemic AL amyloidosis, ECV detects subclinical myocardial alterations. With therapy, ECV tends to increase at 6 months and returns to values unchanged from baseline at 12 months, whereas GLS improves at 6 and 12 months in participants with AL-CMP. ECV and GLS offer additional prognostic performance over Mayo stage. (Molecular Imaging of Primary Amyloid Cardiomyopathy [MICA]; NCT02641145)., Competing Interests: Funding Support and Author Disclosures This work was supported by National Institutes of Health. Dr Dorbala was supported by grants R01 HL 130563, K24 HL 157648, AHA16 CSA 2888 0004, and AHA19SRG34950011. Dr Falk was supported by grant R01 HL 130563. Dr Liao was supported by grants AHA16 CSA 2888 0004 and AHA19SRG34950011. Dr Ruberg was supported by grants R01 HL 130563 and R01 HL 093148. Dr Cuddy was supported by grants NIH 1K23HL166686-01 and AHA 23CDA857664NIH. Dr Bianchi was partially supported by a grant K08 CA245100. Dr Clerc has received a research fellowship from the International Society of Amyloidosis and Pfizer. Dr Cuddy has received an investigator-initiated research grant from Pfizer, as well as consulting fees from BridgeBio, Ionis, Astra Zeneca and Novo Nordisk. Dr Bianchi has received consulting fees from Prothena. Dr Ruberg has received consulting fees from AstraZeneca and Attralus; and has received research support from Pfizer, Alnylam, Anumana, and Ionis/Akcea. Dr DiCarli has received a research grant from Spectrum Dynamics and Gilead; and has received consulting fees from Sanofi and General Electric. Dr Kwong has received grant funding from Alynlam Pharmaceuticals. Dr Falk has received consulting fees from Ionis Pharmaceuticals, Alnylam Pharmaceuticals, and Caelum Biosciences; and has received research funding from GlaxoSmithKline and Akcea. Dr Dorbala has received consulting fees from Pfizer, GE Healthcare, and Novo Nordisk; and has received investigator-initiated grants from Pfizer, GE Healthcare, Attralus, Siemens, and Phillips. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Aortic stenosis (AS) and transthyretin (ATTR) cardiac amyloidosis (CA) share the same clinical profiles and cardiac phenotype. Amyloid deposits have been frequently reported in aortic valves of patients with severe AS referred for surgical aortic valve replacement (SAVR). The aim of this study was to determine the clinical and myocardial status of patients with aortic valve amyloidosis after aortic valve surgery., Methods and Results: We performed a retrospective descriptive study of 46 patients who underwent SAVR for severe AS with amyloid deposits upon histological analysis. All patients were screened for cardiac involvement. Amyloid deposits typing was successful in 35 (76%) patients and 28 (80%) were ATTR. Two (4%) had positive bone scintigraphy and among the 5 myocardial biopsies performed during surgery, 80% were positive for ATTR deposits., Conclusion: ATTR is the predominant type in the presence of amyloid deposits on the aortic valve after surgery for severe AS but is only rarely accompanied by cardiac uptake on bone scintigraphy. Early stages of myocardial involvement are frequent and myocardial biopsy is more sensitive for detection of mild amyloid deposits than bone scintigraphy., Competing Interests: Declaration of competing interest Jean-Baptiste Brette: none, Magali Colombat: grant from Pfizer France, Pauline Fournier: consultancies form Pfizer France, Maxime Moninhas: none, Bertrand Marcheix: none, Olivier Lairez: consultancies form Pfizer France and Alnylam, Eve Cariou: consultancies form Pfizer France., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Cardiac fibrosis is a significant driver of congestive heart failure, a syndrome that continues to affect a growing patient population globally. Cardiac fibrosis results from a constellation of complex processes at the transcription, receptor, and signaling axes levels. Various mediators and signaling cascades, such as the transformation growth factor-beta pathway, have been implicated in the pathophysiology of cardiac tissue fibrosis. Our understanding of these markers and pathways has improved in recent years as more advanced technologies and assays have been developed, allowing for better delineation of the crosstalk between specific factors. There is mounting evidence suggesting that epigenetic modulation plays a pivotal role in the progression of cardiac fibrosis. Transcriptional regulation of key pro- and antifibrotic pathways can accentuate or blunt the rate and extent of fibrosis at the tissue level. Exosomes, micro-RNAs, and long noncoding RNAs all belong to factors that can impact the epigenetic signature in cardiac fibrosis. Herein, we comprehensively review the latest literature about exosomes, their contents, and cardiac fibrosis. In doing so, we highlight the specific transcriptional factors with pro- or antifibrotic properties. We also assimilate the data supporting these mediators' potential utility as diagnostic or prognostic biomarkers. Finally, we offer insight into where further work can be done to fill existing gaps to translate preclinical findings better and improve clinical outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: FLNC gene variants have predominantly been reported in adult populations with cardiomyopathies, and early-onset cases are less common. The genotype-phenotype relationship indicates that dilated cardiomyopathy (DCM) is often associated with FLNC truncating variants., Methods: We conducted a comprehensive genetic analysis using next generation sequencing (NGS) to identify FLNC variants in patients with cardiovascular conditions. Detailed phenotypic and variant analyses were performed to characterize the clinical features and genetic alterations. Minigene assays and structural modeling were used to investigate the pathogenicity caused by the identified variants., Results: In a cohort of 58 patients, novel heterozygous FLNC variants, c.3962A > T (p.Glu1321Val) and c.7543C > T (p.Leu2515Phe), were identified in patients presenting with dilated and mixed restrictive/hypertrophic cardiomyopathies, respectively. The c.3962A > T variant disrupted normal splicing, as demonstrated through the splicing prediction tool and minigene studies, further emphasizing its pathogenic potential., Conclusion: For missense variants of FLNC in patients with DCM, the splicing effect of the variant should be carefully checked. Early detection and intervention are crucial given the high risk of sudden cardiac death and severe cardiac complications., (© 2024. The Author(s).)

Heart Failure with Preserved Ejection Fraction (HFpEF) is one of the most frequent causes of heart failure in the world's population (about 19-55%), and is commonly associated with a high rate of hospitalization (almost 70-80%) and with increased mortality (40-50% in a 5-year timeframe). The elderly are more often affected, with higher rates of hospitalizations than young people, and currently almost 70% of the population aged 65 years old has HFpEF. An increase in cardiomyocyte stiffness, thus resulting in diastolic dysfunction, increased filling pressures and heart failure with preserved ejection fraction are characteristics features of the disease. In addition, among the various causes of HFpEF, cardiac amyloidosis (CA) can provoke diastolic dysfunction and increased wall stiffness directly from intercellular deposition of insoluble proteic substances and their toxic activity. Totally, almost 30 different proteins are able to form deposits, but the most frequently involved are transthyretin and misfolded monoclonal immunoglobulin light chains, which bring to two clinical conditions called transthyretin amyloidosis (ATTR) and light-chain amyloidosis (AL). Although there has been increasing attention on ATTR-CA in recent years, the actual prevalence remains underestimated, especially in people of advanced age, as well as its real impact as a cause of HFpEF, and only data derived from autoptic exams are currently available. Moreover, CA itself often mimics HFpEF, and some conflicting data on the use of predictive scores are described in the literature. The close relationship between HFpEF and CA, especially in older population and the main pathophysiological mechanisms which bond these two conditions are described in this focused review. The need to screen red flags for ATTR-CA in elderly patients with HFpEF is urgently advised, because a prompt recognition of the disease can optimize the approach to the disease with an early therapeutic, life-saving choice.

Background: We aimed to clarify the existence and pathological features of obesity cardiomyopathy (OCM) in Japan using our series of autopsy cases., Methods: In this retrospective autopsy study, OCM was defined as cardiac hypertrophy (≥ 400 g in men, ≥ 320 g in women) of unknown aetiology in individuals with obesity (body mass index [BMI] ≥ 25 kg/m 2 according to the Japanese definition of obesity). We compared cases of OCM with those with obesity without cardiac hypertrophy (OB) and normal weight without cardiac hypertrophy (normal control). Macroscopically, heart weight and cardiac parameters, including epicardial adipose tissue, were measured. Fibrosis, cardiomyocyte diameter, and adipose tissue infiltration were analysed microscopically., Results: Of the 294 cases, we identified 19 cases of OCM (6.5%) and compared them with the OB and normal control groups. Patients with OCM were slightly younger than non-OCM patients (p = 0.081). The median heart weight was significantly heavier in OCM cases than in OB cases (435 g, interquartile range [IQR] 408-515 g vs. 360 g, IQR 341-385 g). Macroscopically, OCM hearts had a "globoid" appearance with a thickened right ventricular outflow tract. Some OCM cases showed focal interstitial fibrosis in the left ventricle. Approximately half the OCM cases were diagnosed with sudden cardiac death (SCD), with significant differences., Conclusions: The prevalence of OCM may be higher than expected in Japan, and this may be a specific pathological finding. Given that approximately half the cases of OCM were due to SCD, OCM may cause SCD, emphasizing the need to recognise and diagnose OCM., (© 2024. The Author(s).)

HIV-associated cardiovascular diseases remain a leading cause of death in people living with HIV/AIDS (PLWHA). Although antiretroviral drugs suppress the viral load, they fail to remove the virus entirely. HIV-1 Nef protein is known to play a role in viral virulence and HIV latency. Expression of Nef protein can be detected in different organs, including cardiac tissue. Despite the established role of Nef protein in HIV-1 replication, its impact on organ function inside the human body is not clear. To understand the effect of Nef at the organ level, we created a new Nef-transgenic (Nef-TG) mouse that expresses Nef protein in the heart. Our study found that Nef expression caused inhibition of cardiac function and pathological changes in the heart with increased fibrosis, leading to heart failure and early mortality. Further, we found that cellular autophagy is significantly inhibited in the cardiac tissue of Nef-TG mice. Mechanistically, we found that Nef protein causes the accumulation of Bcl2 and Beclin-1 proteins in the tissue, which may affect the cellular autophagy system. Additionally, we found Nef expression causes upregulation of the cellular senescence marker p21 and senescence-associated β-galactosidase expression. Our findings suggest that the Nef-mediated inhibition of autophagy and induction of senescence markers may promote aging in PLWHA. Our mouse model could help us to understand the effect of Nef protein on organ function during latent HIV infection.

The pathogenesis of doxorubicin-induced cardiomyopathy remains unclear. This study was carried out to test our hypothesis that ADAM17 aggravates cardiomyocyte apoptosis induced by doxorubicin and inhibition of ADAM17 may ameliorate doxorubicin-induced cardiomyopathy. C57BL/6J mice were intraperitoneally injected with a cumulative dose of doxorubicin to induce cardiomyopathy. Cardiomyocyte-specific ADAM17-knockout (A17 α-MHCKO ) and ADAM17-overexpressing (AAV9-oeA17) mice were generated. In addition, RNA sequencing of the heart tissues in different mouse groups and in vitro experiments in neonatal rat cardiomyocytes (NRCMs) receiving different treatment were performed. Mouse tumor models were constructed in A17 fl/fl and A17 α-MHCKO mice. In addition, cardiomyocyte-specific TRAF3-knockdown and TRAF3-overexpressing mice were generated. ADAM17 expression and activity were markedly upregulated in doxorubicin-treated mouse hearts and NRCMs. A17 α-MHCKO mice showed less cardiomyocyte apoptosis induced by doxorubicin than A17 fl/fl mice, and cardiomyocyte ADAM17 deficiency did not affect the anti-tumor effect of doxorubicin. In contrast, AAV9-oeA17 mice exhibited markedly aggravated cardiomyocyte apoptosis relative to AAV9-oeNC mice after doxorubicin treatment. Mechanistically, doxorubicin enhanced the expression of transcription factor C/EBPβ, leading to increased expression and activity of ADAM17 in cardiomyocyte, which enhanced TNF-α shedding and upregulated the expression of TRAF3. Increased TRAF3 promoted TAK1 autophosphorylation, resulting in activated MAPKs pathway and cardiomyocyte apoptosis. ADAM17 acted as a positive regulator of cardiomyocyte apoptosis and cardiac remodeling and dysfunction induced by doxorubicin by upregulating TRAF3/TAK1/MAPKs signaling. Thus, targeting ADAM17/TRAF3/TAK1/MAPKs signaling holds a promising potential for treating doxorubicin-induced cardiotoxicity., (© 2024. The Author(s).)

Background: Bone scintigraphy (BS) is established as an accurate, non-invasive method for the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM). In a real-life setting, however, some patients with no cardiac uptake on BS turn out to have cardiac-biopsy-confirmed ATTR-CM. We retrospectively included all patients diagnosed at the French Referral Center for ATTR-CM and who had data for BS and a cardiac biopsy., Results: Of 271 patients with positive cardiac biopsy, 14 (5%) had no cardiac uptake on 99m Tc-hydroxymethylene diphosphonate BS. Cardiac uptake was found in four of the seven patients who had a second BS assessment with 99m Tc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD). A retrospective review of the BS data found low cardiac uptake in four patients (two with HMDP and two with both radiotracers). Ultimately, six of the 14 patients with a biopsy-confirmed diagnosis of ATTR-CM did not show any cardiac radiotracer uptake., Conclusions: An endomyocardial biopsy may be necessary for confirming the diagnosis of ATTR-CM in patients with clinical and imaging signs of cardiac amyloidosis but no cardiac radiotracer uptake in BS., (© 2024. The Author(s).)

Background: Immunoglobulin derived AL amyloidosis and transthyretin derived ATTR amyloidosis are the most common forms of cardiac amyloidosis. Both may present with cardiac arrhythmias, heart failure, and extracardiac symptoms. Disease outcome is often fatal. Recently, it was proposed that amyloid may cause cardiac inflammation. Here we tested the hypothesis that immune cell infiltration in cardiac tissue correlates with clinicopathological patient characteristics., Patients and Methods: Myocardial biopsies from 157 patients with cardiac amyloidosis (46.5% AL, 53.3% ATTR) were immunohistochemically assessed for the presence and amount of T lymphocytes (CD3), macrophages (CD68) and neutrophils (MPO). Amyloid load, cardiomyocyte diameter, apoptosis (Caspase 3), necrosis (complement 9), and various clinical parameters were assessed and correlated with immune cell density., Results: Myocardial tissue was infiltrated with T lymphocytes (CD3), macrophages (CD68) and neutrophils (MPO) with variable amounts. Significant correlations were found between the number of macrophages and NYHA class. No correlations were found between the presence and amount of T lymphocytes, neutrophils and clinicopathological patient characteristics., Conclusion: The significant correlation between cardiac macrophage density and heart failure points towards a significant role of macrophages in disease pathology., (© 2024. The Author(s).)

Cardiovascular diseases are a major cause of death worldwide. Advanced in vitro models can be the key stone for a better understanding of the mechanisms at the basis of the different pathologies, supporting the development of novel therapeutic protocols. In particular, the implementation of induced pluripotent stem cell (iPSC) technology allows for the generation of a patient-specific pluripotent cell line that is able to differentiate in several organ-specific cell subsets while retaining the patient genetic background, thus putting the basis for personalized in vitro modeling toward personalized medicine. The design of iPSC-based models able to recapitulate the complexity of the cardiac environment is a critical goal. Here, we review some of the published efforts to exploit three dimensional (3D) iPSC-based methods to recapitulate the relevant cardiomyopathies, including genetically and non-genetically determined cardiomyopathies and cardiotoxicity studies. Finally, we discuss the actual method limitations and the future perspectives in the field.

Cardiac involvement is the most important factor determining prognosis in patients with systemic amyloidosis. This retrospective observational study of 98 patients with amyloidosis was undertaken to assess the amyloid types that are most likely to affect the heart, describe histopathological and clinical features of cardiac amyloidosis, and estimate the number of cases not diagnosed clinically prior to death. All cases were divided into two groups based on the method of examination. The first group included 46 patients with cardiac amyloidosis revealed via endomyocardial biopsies (EMBs), and the second group included 52 amyloidosis patients who did not undergo EMBs, in whom cardiac involvement was identified only at autopsy. The EMBs demonstrated that AL amyloidosis was detected in 21 (46%) specimens, ATTR amyloid in 24 cases (52%), and AA amyloid in 1 case (2%). The autopsy reports defined 15 (46%) cases of AL amyloidosis, 21 (40%) of ATTR and 16 (31%) of AA amyloidosis. It should be noted that a clinical diagnosis of ATTR amyloidosis was made only in 9.5% of patients from the autopsy group, suggesting that ATTR may be an underdiagnosed cause of heart failure in elderly patients. The most intense amyloid deposits were determined in biopsy and autopsy specimens of patients with AL kappa amyloidosis, underlying a poorer prognosis.

Background: Sepsis often leads to cardiomyopathy, contributing to increased mortality rates. 2,6-Diisopropylphenol (propofol), an anesthetic, has demonstrated efficacy in protecting cardiomyocytes from cell death caused by hypoxia and reoxygenation. This study examined the effects of propofol on sepsis-associated myocardial dysfunction and explored the underlying mechanism of action., Methods: Mice and rat cardiomyocytes (H9C2 cell line) were used to establish a sepsis-induced myocardial dysfunction model. Lipopolysaccharides (LPS)-treated mice and H9C2 cells were treated with propofol, with rapamycin used for mechanistic studies in H9C2 cells. Cardiac function was evaluated by echocardiographic measurements. Heart tissues were stained with hematoxylin and eosin, and heart weight/body weight ratio along with the levels of cardiac biomarkers were measured using Enzyme Linked Immunosorbent Assay (ELISA). Activation of the mammalian target of rapamycin (mTOR) pathway was assessed by western blotting. Apoptosis in heart tissues and H9C2 cells was evaluated using Terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling (TUNEL) assay, and cell viability was quantified using Cell Counting Kit (CCK)-8 assay. Oxidative stress in H9C2 cells was assessed by measuring reactive oxygen species (ROS) levels through immunofluorescence staining and malondialdehyde (MDA) and superoxide dismutase (SOD) levels using ELISA., Results: Propofol reversed LPS-induced myocardial changes and cardiac dysfunction ( p < 0.05). In mouse tissues and H9C2 cells, propofol reversed LPS-induced mTOR pathway inhibition and apoptosis ( p < 0.001). Moreover, propofol alleviated oxidative stress in LPS-treated cells. The activation of the mTOR pathway by propofol, along with its inhibitory effects on oxidative stress and apoptosis in cardiomyocytes, was negated by rapamycin ( p < 0.001)., Conclusion: Propofol ameliorates sepsis-induced myocardial dysfunction triggered by LPS through the mTOR pathway, thereby promoting antioxidative stress and reducing cell apoptosis.

Adriamycin is an anticancer anthracycline drug that inhibits the progression of topoisomerase II activity and causes apoptosis. The effective clinical application of the drug is very much limited by its adverse drug reactions on various tissues. Most importantly, Adriamycin causes cardiomyopathy, one of the life-threatening complications of the drug. Altered expression of PPARγ in adipocytes inhibited the glucose and fatty acids uptake by down regulating GLUT4 and CD36 expression and causes cardiotoxicity. Therefore, the influence of Adriamycin in cardiac ailments was investigated in vivo and in vitro. Adriamycin treated rats showed altered ECG profile, arrhythmic heartbeat with the elevated levels of CRP and LDH. Dysregulated lipid profiles with elevated levels of cholesterol and triglycerides were also observed. Possibilities of cardiac problems due to cardiomyopathy were analyzed through histopathology. Adriamycin treated rats showed no signs for atheromatous plaque formation in aorta but disorganized cardiomyocytes with myofibrillar loss and inflammation in heart tissue, indicative of cardiomyopathy. Reduced levels of antioxidant enzymes confirmed the incidence of oxidative stress. Adriamycin treatment significantly reduced glucose and insulin levels, creating energy demand due to decreased glucose and insulin levels with increased fatty acid accumulation, ultimately resulting in oxidative stress mediated cardiomyopathy. Since PPARs play a vital role in regulating oxidative stress, the effect of Adriamycin on PPARγ was analyzed by western blot. Adriamycin downregulated PPARγ in a dose-dependent manner in H9C2 cells in vitro. Overall, our study suggests that Adriamycin alters glucose and lipid metabolism via PPARγ inhibition that leads to oxidative stress and cardiomyopathy that necessitates a different therapeutic approach., (© 2024 Wiley Periodicals LLC.)

Quercetin (QUE) has been found to inhibit the progression of sepsis-related diseases, including sepsis-induced cardiomyopathy (SIC). More information about the role and mechanism of QUE in SIC progression deserves further exploration. Human cardiomyocytes (AC16) were induced with LPS to mimic SIC cell models. Cell proliferation and apoptosis were determined using CCK8 assay, EdU assay, and flow cytometry. Cell inflammation and ferroptosis were evaluated by detecting IL-1β, TNF-α, Fe 2+ , ROS, GSH, and GPX4 levels. 5-lipoxygenase (ALOX5) expression was examined by quantitative real-time PCR and western blot. LPS treatment reduced AC16 cell proliferation, while enhanced apoptosis, inflammation, and ferroptosis. QUE repressed LPS-induced AC16 cell apoptosis, inflammation, and ferroptosis. ALOX5 was upregulated in SIC patients, and its expression was reduced by QUE. ALOX5 knockdown restrained LPS-induced apoptosis, inflammation, and ferroptosis in AC16 cells. The inhibitory effect of QUE on LPS-induced myocardial injury could be reversed by ALOX5 overexpression. QUE promoted the activity of PI3K/AKT pathway by reducing ALOX5 expression. QUE could alleviate LPS-induced myocardial injury by regulating ALOX5/PI3K/AKT pathway, suggesting that QUE might be used for treating SIC., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Muscle atrophy and weakness are prevalent features of cancer. Although extensive research has characterized skeletal muscle wasting in cancer cachexia, limited studies have investigated how cardiac structure and function are affected by therapy-naive cancer. Herein, orthotopic, syngeneic models of epithelial ovarian cancer and pancreatic ductal adenocarcinoma, and a patient-derived pancreatic xenograft model, were used to define the impact of malignancy on cardiac structure, function, and metabolism. Tumor-bearing mice developed cardiac atrophy and intrinsic systolic and diastolic dysfunction, with arterial hypotension and exercise intolerance. In hearts of ovarian tumor-bearing mice, fatty acid-supported mitochondrial respiration decreased, and carbohydrate-supported respiration increased-showcasing a substrate shift in cardiac metabolism that is characteristic of heart failure. Epithelial ovarian cancer decreased cytoskeletal and cardioprotective gene expression, which was paralleled by down-regulation of transcription factors that regulate cardiomyocyte size and function. Patient-derived pancreatic xenograft tumor-bearing mice show altered myosin heavy chain isoform expression-also a molecular phenotype of heart failure. Markers of autophagy and ubiquitin-proteasome system were upregulated by cancer, providing evidence of catabolic signaling that promotes cardiac wasting. Together, two cancer types were used to cross-validate evidence of the structural, functional, and metabolic cancer-induced cardiomyopathy, thus providing translational evidence that could impact future medical management strategies for improved cancer recovery in patients., (Copyright © 2024 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Septic cardiomyopathy (SCM) is the main cause of death in critically ill patients with sepsis. However, its definitive pathogenic mechanisms remain to be elucidated. Lipid droplets (LDs) are important sub-organelles that store lipids and participate in intracellular lipid metabolism. Abnormal aggregation and altered polarity of LDs are associated with the development of several cardiac diseases. To date, visualization of abnormal polarity in models of SCM has not been achieved. Herein, we designed and synthesized the probe BDP-551, a polarity-sensitive probe possessing a donor-π-acceptor (D-π-A) structure. BDP-551 exhibits excellent photostability, high LDs targeting, near-infrared (NIR) emission (up to 678 nm) and strong polarity sensitivity. With the help of confocal imaging microscopy, the BDP-551 was able to detect the polarity changes induced in the SCM model cells and visualize the yolk sac region in hypoxic as well as inflamed living zebrafish. In addition, the BDP-551 has been successfully applied to visualize the polarity changes of mice hearts with SCM, proving a decrease of microenvironmental polarity in the development of SCM. Therefore, BDP-551 in this study can be used as a reliable tool to investigate polarity fluctuations and provide new insights into the associated pathogenic and therapeutic mechanisms on SCM., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Myocardial fibrosis involves the loss of cardiomyocytes, myocardial fibroblast proliferation, and a reduction in angiogenesis, ultimately leading to heart failure, Given its significant implications, it is crucial to explore novel therapies for myocardial fibrosis. Recently one emerging avenue has been the use of small extracellular vesicles (sEV)-carried miRNA. In this review, we summarize the regulatory role of sEV-carried miRNA in myocardial fibrosis. We explored not only the potential diagnostic value of circulating miRNA as biomarkers for heart disease but also the therapeutic implications of sEV-carried miRNA derived from various cellular sources and applications of modified sEV. This exploration is paramount for researchers striving to develop innovative, cell-free therapies as potential drug candidates for the management of myocardial fibrosis., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Min Cheng reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Sepsis is a global health challenge that results in systemic inflammation, oxidative stress, and multi-organ dysfunction, with the heart being particularly susceptible. This study aimed to elucidate the effect of FTO, a key regulator in m 6 A methylation in septic cardiomyopathy, and its potential therapeutic implications. Cellular and animal models of septic myocardial injury were established. Moreover, it was revealed that ferroptosis, which is a form of programmed necrosis occurring with iron dependence, was activated within cardiomyocytes during septic conditions. The overexpression of FTO-suppressed ferroptosis alleviated heart inflammation and dysfunction and improved survival rates in vivo. However, the protective effects of FTO were attenuated by the overexpression of BACH1, which is a molecule negatively correlated with FTO. Mechanistically, FTO modulated the m 6 A modification of BACH1, suggesting a complex interplay in the regulation of cardiomyocyte damage and sepsis. Our findings reveal the potential of targeting the FTO/BACH1 axis and ferroptosis inhibitors as therapeutic strategies for sepsis-induced cardiac injuries., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Obesity causes a range of tissue dysfunctions that increases the risk for morbidity and mortality. Protein kinase D (PKD) represents a family of stress-activated intracellular signalling proteins that regulate essential processes such as cell proliferation and differentiation, cell survival, and exocytosis. Evidence suggests that PKD regulates the cellular adaptations to the obese environment in metabolically important tissues and drives the development of a variety of diseases. This review explores the role that PKD plays in tissue dysfunction in obesity, with special consideration of the development of obesity-mediated cardiomyopathy, a distinct cardiovascular disease that occurs in the absence of common comorbidities and leads to eventual heart failure and death. The downstream mechanisms mediated by PKD that could contribute to dysfunctions observed in the heart and other metabolically important tissues in obesity, and the predicted cell types involved are discussed to suggest potential targets for the development of therapeutics against obesity-related disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Doxorubicin (DOX) is an effective chemotherapeutic drug, but its use can lead to cardiomyopathy, which is the leading cause of mortality among cancer patients. Macrophages play a role in DOX-induced cardiomyopathy (DCM), but the mechanisms undlerlying this relationship remain unclear. This study aimed to investigate how IKKα regulates macrophage activation and contributes to DCM in a mouse model. Specifically, the role of macrophage IKKα was evaluated in macrophage-specific IKKα knockout mice that received DOX injections. The findings revealed increased expression of IKKα in heart tissues after DOX administration. In mice lacking macrophage IKKα, myocardial injury, ventricular remodeling, inflammation, and proinflammatory macrophage activation worsened in response to DOX administration. Bone marrow transplant studies confirmed that IKKα deficiency exacerbated cardiac dysfunction. Macrophage IKKα knockout also led to mitochondrial damage and metabolic dysfunction in macrophages, thereby resulting in increased cardiomyocyte injury and oxidative stress. Single-cell sequencing analysis revealed that IKKα directly binds to STAT3, leading to the activation of STAT3 phosphorylation at S727. Interestingly, the inhibition of STAT3-S727 phosphorylation suppressed both DCM and cardiomyocyte injury. In conclusion, the IKKα-STAT3-S727 signaling pathway was found to play a crucial role in DOX-induced cardiomyopathy. Targeting this pathway could be a promising therapeutic strategy for treating DOX-related heart failure., (© 2024. The Author(s).)

Background: Doxorubicin is an important anticancer drug, however, elicits dose-dependently cardiomyopathy. Given its mode of action, i.e. topoisomerase inhibition and DNA damage, we investigated genetic events associated with cardiomyopathy and searched for mechanism-based possibilities to alleviate cardiotoxicity. We treated rats at clinically relevant doses of doxorubicin. Histopathology and transmission electron microscopy (TEM) defined cardiac lesions, and transcriptomics unveiled cardiomyopathy-associated gene regulations. Genomic-footprints revealed critical components of Abl1-p53-signaling, and EMSA-assays evidenced Abl1 DNA-binding activity. Gene reporter assays confirmed Abl1 activity on p53-targets while immunohistochemistry/immunofluorescence microscopy demonstrated Abl1, p53&p73 signaling., Results: Doxorubicin treatment caused dose-dependently toxic cardiomyopathy, and TEM evidenced damaged mitochondria and myofibrillar disarray. Surviving cardiomyocytes repressed Parkin-1 and Bnip3-mediated mitophagy, stimulated dynamin-1-like dependent mitochondrial fission and induced anti-apoptotic Bag1 signaling. Thus, we observed induced mitochondrial biogenesis. Transcriptomics discovered heterogeneity in cellular responses with minimal overlap between treatments, and the data are highly suggestive for distinct cardiomyocyte (sub)populations which differed in their resilience and reparative capacity. Genome-wide footprints revealed Abl1 and p53 enriched binding sites in doxorubicin-regulated genes, and we confirmed Abl1 DNA-binding activity in EMSA-assays. Extraordinarily, Abl1 signaling differed in the heart with highly significant regulations of Abl1, p53 and p73 in atrial cardiomyocytes. Conversely, in ventricular cardiomyocytes, Abl1 solely-modulated p53-signaling that was BAX transcription-independent. Gene reporter assays established Abl1 cofactor activity for the p53-reporter PG13-luc, and ectopic Abl1 expression stimulated p53-mediated apoptosis., Conclusions: The tyrosine kinase Abl1 is of critical importance in doxorubicin induced cardiomyopathy, and we propose its inhibition as means to diminish risk of cardiotoxicity., (© 2024. The Author(s).)

Objective Although magnetic resonance imaging (MRI) is the gold standard for evaluating abnormal myocardial fibrosis and extracellular volume (ECV) of the left ventricular myocardium (LVM), a similar evaluation has recently become possible using computed tomography (CT). In this study, we investigated the diagnostic accuracy of a new 256-row multidetector CT with a low tube-voltage single energy scan and deep-learning-image reconstruction (DLIR) in detecting abnormal late enhancement (LE) in LVM. Methods We evaluated the diagnostic performance of CT for detecting LE in LVM and compared the results with those of MRI as a reference. We also measured the ECV of the LVM on CT and compared the results with those on MRI. Materials We analyzed 50 consecutive patients who underwent cardiac CT, including a late-phase scan and MRI, within three months of suspected cardiomyopathy. All patients underwent 256-slice CT (Revolution APEX; GE Healthcare, Waukesha, USA) with a low tube-voltage (70 kV) single energy scan and DLIR for a late-phase scan. Results In patient- and segment-based analyses, the sensitivity, specificity, and accuracy of detection of LE on CT were 94% and 85%, 100% and 95%, and 96% and 93%, respectively. The ECV of LVM per patient on CT and MRI was 33.0±6.2% and 35.9±6.1%, respectively. These findings were extremely strongly correlated, with a correlation coefficient of 0.87 (p<0.0001). The effective radiation dose on late-phase scanning was 2.4±0.9 mSv. Conclusion The diagnostic performance of 256-row multislice CT with a low tube voltage and DLIR for detecting LE and measuring ECV in LVM is credible.

Sepsis is a life-threatening situation that ultimately affects cardiac function, leading to cardiomyopathy and myocardial injury as a result of uncontrolled response to infection.Till now, there is limited effective treatment to rescue those cases. Thus, novel therapeutic strategies should be identified to achieve better outcomes for septic patients. For the first time, we aimed to evaluate the effect of sacubitril/valsartan (Sac/Val) on sepsis-induced cardiac injury. Wistar male adult albino rats were randomly divided into four groups; Group I received the vehicle; Group II was given the vehicle plus 1 ml saline containing viable Escherichia coli (E. coli) (2.1 × 10 9  cfu) by intraperitoneal (i.p.) injection on the 1st and 2nd days; Group III received i.p. injection as group II plus oral administration of Sac/Val (30 mg/kg/day) and Nitro- ω-L-arginine (L-NNA) (25 mg/kg/day) for 7 days. Group IV was administered i.p. injection as group II plus oral administration of Sac/Val (30 mg/kg/day) for 7 days. Our data (n = 10) revealed successful induction of sepsis as it showed a significant increase in the measured cardiac enzymes, malondialdehyde (MDA), angiotensin II (Ang II), neprilysin, inflammasome, caspase 1, interleukin (IL)1β, and caspase 3 with cardiac histopathological changes, but there was a significant decrease in the antioxidants and blood pressure (BP). Co-administration of Sac/Val could obviously improve these changes. Interestingly, L-NNA given group showed a decrease in the cardioprotective effect of Sac/Val. Sac/Val could ameliorate sepsis induced cardiac damage via inhibition of Ang II and neprilysin with anti-inflammatory, anti-oxidant and anti-apoptotic properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Left atrial (LA) fibrosis is a marker of atrial cardiomyopathy and has been reported to be associated with both atrial fibrillation and ischemic stroke. Elucidating this relationship is clinically important as LA fibrosis could serve as a surrogate biomarker of LA cardiomyopathy. The objective of this study is to investigate the association of LA fibrosis and embolic stroke of undetermined source (ESUS) using cardiac magnetic resonance imaging., Methods and Results: Following an International Prospective Register of Systematic Reviews-registered protocol, 3 blinded reviewers performed a systematic review for studies that quantified the degree of LA fibrosis in patients with ESUS as compared with healthy patients from inception to February 2024. A meta-analysis was conducted in the mean difference. From 7 studies (705 patients), there was a significantly higher degree of LA fibrosis in patients with ESUS compared with healthy controls (MD, 5.71% [95% CI, 3.55%-7.87%], P <0.01). The degree of LA fibrosis was significantly higher in patients with atrial fibrillation than healthy controls (MD, 8.22% [95% CI, 5.62%-10.83%], P <0.01). A similar degree of LA fibrosis was observed in patients with ESUS compared with patients with atrial fibrillation (MD, -0.92% [95% CI, -2.29% to 0.44%], P =0.35)., Conclusions: A significantly higher degree of LA fibrosis was found in patients with ESUS as compared with healthy controls. This suggests that LA fibrosis may play a significant role in the pathogenesis of ESUS. Further research is warranted to investigate LA fibrosis as a surrogate biomarker of atrial cardiomyopathy and recurrent stroke risk in patients with ESUS.

Background: HIF (hypoxia inducible factor) regulates many aspects of cardiac function. We and others previously showed that chronic HIF activation in the heart in mouse models phenocopies multiple features of ischemic cardiomyopathy in humans, including mitochondrial loss, lipid accumulation, and systolic cardiac dysfunction. In some settings, HIF also causes the loss of peroxisomes. How, mechanistically, HIF promotes cardiac dysfunction is an open question., Methods: We used mice lacking cardiac pVHL (von Hippel-Lindau protein) to investigate how chronic HIF activation causes multiple features of ischemic cardiomyopathy, such as autophagy induction and lipid accumulation. We performed immunoblot assays, RNA sequencing, mitochondrial and peroxisomal autophagy flux measurements, and live cell imaging on isolated cardiomyocytes. We used CRISPR-Cas9 gene editing in mice to validate a novel mediator of cardiac dysfunction in the setting of chronic HIF activation., Results: We identify a previously unknown pathway by which cardiac HIF activation promotes the loss of mitochondria and peroxisomes. We found that DEPP1 (decidual protein induced by progesterone 1) is induced under hypoxia in a HIF-dependent manner and localizes inside mitochondria. DEPP1 is both necessary and sufficient for hypoxia-induced autophagy and triglyceride accumulation in cardiomyocytes ex vivo. DEPP1 loss increases cardiomyocyte survival in the setting of chronic HIF activation ex vivo, and whole-body Depp1 loss decreases cardiac dysfunction in hearts with chronic HIF activation caused by VHL loss in vivo., Conclusions: Our findings identify DEPP1 as a key component in the cardiac remodeling that occurs with chronic ischemia., Competing Interests: W.G.K. has financial interests in Lilly Pharmaceuticals, Fibrogen, Nextech Invest, Tango Therapeutics, LifeMine Therapeutics, Circle Pharma, IconOVir Bio, and Casdin Capital. The other authors report no conflicts.

Sepsis-induced cardiomyopathy (SIC) is described as a reversible myocardial depression that occurs in patients with septic shock. Increasing evidence shows that microRNA-194-5p (miR-194-5p) participates in the regulation of oxidative stress, mitochondrial dysfunction, and apoptosis and its expression is associated with the occurrence and progression of cardiovascular disease; however, the effects of miR-194-5p in SIC are still unclear. This study explores whether miR-194-5p could modulate SIC by affecting oxidative stress, mitochondrial function, and apoptosis. Experimental septic mice were induced by intraperitoneal injection of lipopolysaccharide (LPS) in C57BL/6J mice. The biological role of miR-194-5p in SIC in vivo was investigated using cardiac echocardiography, ELISA, western blot, qRT-PCR, transmission electron microscopy, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, bioinformatics analysis, and dual-luciferase reporter gene assay. Our major finding is that miR-194-5p antagomir mitigates sepsis-induced cardiac dysfunction, inflammation, oxidative stress, apoptosis and mitochondrial dysfunction in the hearts of septic mice, while miR-194-5p agomir triggers the opposite effects. Furthermore, dual-specificity phosphatase 9 (DUSP9) is a direct target of miR-194-5p and the cardioprotective effects of miR-194-5p antagomir on cardiac dysfunction, inflammation, apoptosis, mitochondrial dysfunction and oxidative stress are abolished through inhibiting DUSP9. Therefore, miR-194-5p inhibition could mitigate SIC via DUSP9 in vivo and the novel miR-194-5p/DUSP9 axis might be the potential treatment targets for SIC patients., (© 2024. The Author(s).)

Alström syndrome (AS) is an inherited rare ciliopathy characterised by multi-organ dysfunction and premature cardiovascular disease. This may manifest as an infantile-onset dilated cardiomyopathy with significant associated mortality. An adult-onset restrictive cardiomyopathy may also feature later in life. Loss of function pathogenic variants in ALMS1 have been identified in AS patients, leading to a lack of ALMS1 protein. The biological role of ALMS1 is unknown, particularly in a cardiovascular context. To understand the role of ALMS1 in infantile cardiomyopathy, the reduction of ALMS1 protein seen in AS patients was modelled using human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), in which ALMS1 was knocked out. MuscleMotion analysis and calcium optical mapping experiments suggest that ALMS1 knockout (KO) cells have increased contractility, with altered calcium extrusion and impaired calcium handling dynamics compared to wildtype (WT) counterparts. Seahorse metabolic assays showed ALMS1 knockout iPSC-CMs had increased glycolytic and mitochondrial respiration rates, with ALMS1 knockout cells portraying increased energetic demand and respiratory capacity than WT counterparts. Using senescence associated β-galactosidase (SA-β gal) staining assay, we identified increased senescence of ALMS1 knockout iPSC-CMs. Overall, this study provides insights into the molecular mechanisms in AS, particularly the role of ALMS1 in infantile cardiomyopathy in AS, using iPSC-CMs as a 'disease in a dish' model to provide insights into multiple aspects of this complex disease., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Adipocyte FABP4 (fatty acid-binding protein 4) is augmented in the epicardial stroma of patients with long-standing persistent atrial fibrillation. Because this molecule is released mainly by adipocytes, our objective was to study its role in atrial cardiomyopathy, focusing our attention on fibrosis, metabolism, and electrophysiological changes. These results might clarify the role of adiposity as a mediator of atrial cardiomyopathy., Methods: We used several preclinical cellular models, epicardial and subcutaneous stroma primary cell cultures from patients undergoing open heart surgery, human atrial fibroblasts, atrial cardiomyocytes derived from human induced pluripotent stem cells and isolated from adult mice, and Nav1.5 transfected Chinese hamster ovary cells. Fibrosis, glucose, mitochondrial and adipogenesis activity, gene expression, and proteomics were determined by wound healing, enzymatic, colorimetric, fluorescence assays, real-time quantitative polymerase chain reaction, and TripleTOF proteomics. Molecular changes were analyzed by Raman confocal microspectroscopy, calcium dynamics by confocal microscopy, and ion currents by patch clamp. Epicardial, subcutaneous, and atrial fibroblasts and cardiomyocytes were incubated with FABP4 at 100 ng/mL., Results: Our results showed that FABP4 induced fibrosis, glucose metabolism, and lipid accumulation on epicardial and subcutaneous stroma cells and atrial fibroblasts. Besides, it modified lipid content and calcium dynamics in atrial cardiomyocytes without effects on I Na ., Conclusions: FABP4 exerts fibrotic and metabolic changes on epicardial stroma and modifies lipid content and calcium dynamic on atrial cardiomyocytes. These results suggest its possible role as an atrial cardiomyopathy mediator., Competing Interests: None.

Catecholamine-induced cardiomyopathy (CCM) is an entity associated with increased levels of catecholamines causing subendocardial and papillary muscle cardiomyocyte degeneration and necrosis. In 2020, 49 autopsies from early rabbit deaths in a colony used for medical device biocompatibility studies were submitted for microscopic examination. Of the 49 rabbits, 26 had histologic changes consistent with CCM. No common stressor for CCM was determined in affected rabbits. Animals were generally male, were 12-16-wk-old, and were found dead or had bloating, lethargy, and/or diarrhea. Those observed with clinical signs were euthanized and autopsied per the organization's standard operating procedures. Heart lesions consisted of various degrees of apical subendocardial myocardial degeneration and necrosis. Common non-cardiac lesions included pulmonary congestion and edema, hepatic congestion and centrilobular hepatocellular degeneration, and/or variable intestinal submucosal edema., Competing Interests: Declaration of conflicting interestsThe author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Early identification of immunoglobulin light-chain amyloidosis (AL) is crucial due to its rapid progression. Monoclonal light-chain (M-LC) testing is the first step in the diagnostic workup for patients with suspected cardiac amyloidosis (CA). We aimed to determine whether the time interval between the first CA suspicion and M-LC testing can be related to AL amyloidosis survival outcomes., Methods: All patients ( n  = 94) with isolated cardiac AL amyloidosis diagnosed at our center between 2016 and 2020 were included. Those with pre-existing known monoclonal protein (monoclonal gammopathy of undetermined significance or smoldering multiple myeloma) were excluded. Time intervals to diagnostic tests and diagnosis were calculated and assessed for their survival prediction ability., Results: The time interval between first CA suspicion (on echocardiography) and M-LC testing correlated with early mortality, and the best cutoff predicting survival, was 6 weeks. The 26 patients (∼28% of entire cohort) who underwent M-LC-studies >6 weeks after first suspicion more frequently presented Mayo stage IIIb (65% vs. 35%, p  = .008), showing poorer overall survival than those ( n  = 68, 72%) referred for early M-LC studies (median 3 vs. 14 months, p  = .039)., Conclusions: Monoclonal protein testing should be the first-step in the diagnostic workup for patients with echocardiographic/other instrumental red flags raising CA suspicion.

Background: Cardiac computed tomography quantification of extracellular volume fraction (CT-ECV) is an emerging biomarker of myocardial fibrosis which has demonstrated high reproducibility, diagnostic and prognostic utility. However, there has been wide variation in the CT-ECV protocol in the literature and useful disease cut-offs are yet to be established. The objectives of this meta-analysis were to describe mean CT-ECV estimates and to estimate the effect of CT-ECV protocol parameters on between-study variation., Methods: We conducted a meta-analysis of studies assessing CT-ECV in healthy and diseased participants. We used meta-analytic methods to pool estimates of CT-ECV and performed meta-regression to identify the contribution of protocol parameters to CT-ECV heterogeneity., Results: Thirteen studies had a total of 248 healthy participants who underwent CT-ECV assessment. Studies of healthy participants had high variation in CT-ECV protocol parameters. The pooled estimate of CT-ECV in healthy participants was 27.6% (95%CI 25.7%-29.4%) with significant heterogeneity (I 2  ​= ​93%) compared to 50.2% (95%CI 46.2%-54.2%) in amyloidosis, 31.2% (28.5%-33.8%) in severe aortic stenosis and 36.9% (31.6%-42.3%) in non-ischaemic dilated cardiomyopathies. Meta-regression revealed that CT protocol parameters account for approximately 25% of the heterogeneity in CT-ECV estimates., Conclusion: CT-ECV estimates for healthy individuals vary widely in the literature and there is significant overlap with estimates in cardiac disease. One quarter of this heterogeneity is explained by differences in CT-ECV protocol parameters. Standardization of CT-ECV protocols is necessary for widespread implementation of CT-ECV assessment for diagnosis and prognosis., Competing Interests: Declaration of competing interest None declared., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Sarcoidosis, a granulomatous disorder of unknown etiology affecting multiple organs. It is often a benign disease but can have significant morbidity and mortality when the heart is involved (often presenting with clinical manifestations such as conduction irregularities and heart failure). This study addresses a critical gap in cardiac sarcoidosis (CS) research by developing a robust animal model. The absence of a reliable animal model for cardiac sarcoidosis is a significant obstacle in advancing understanding and treatment of this condition. The proposed model utilizes carbon nanotube injection and transverse aortic constriction as stressors. Intramyocardial injection of carbon nanotubes induces histiocytes typical of sarcoid granulomas in the heart but shows limited effects on fibrosis or cardiac function. Priming the immune system with transverse aortic constriction prior to intramyocardial injection of carbon nanotubes enhances cardiac fibrosis, diminishes cardiac function, and impairs cardiac conduction. This novel, easily executable model may serve as a valuable tool for disease profiling, biomarker identification, and therapeutic exploration., (© 2024 The Author(s). Advanced Biology published by Wiley‐VCH GmbH.)

Histiocytoid cardiomyopathy (HC) is an arrhythmogenic disorder, usually involving children under two years of age with a strong Caucasian and female predominance. The disease is fatal in the vast majority and diagnosis is nearly always established at autopsy, but this is only possible with adequate myocardial sampling. Meticulous gross and histological examination of the heart in collaboration with a cardiovascular-trained pathologist maximises the opportunity to make specific diagnoses (and therefore rule out the differentials of SIDS, SUDC and child abuse), guide genetic testing, and inform potentially life-saving medical interventions for blood relations. We present a typical HC case presenting as sudden death, without prodrome, in a previously healthy 18-month-old boy. The disease is characterised histologically by discrete groups of enlarged, polygonal histiocyte-like cells with distinct margins and abundant faintly eosinophilic foamy cytoplasm. Cells often contain coarse granules, microvacuoles and irregular, round nuclei. In our case, dysplastic fascicles were predominantly located immediately deep to the endocardium of the left ventricle. We report our own autopsy findings with histological images, and discuss the expected clinical, morphological and ultrastructural features of the disease., (© 2023. The Author(s).)

Introduction: Tafamidis is a molecular chaperone that stabilizes the transthyretin (TTR) homo-tetramer, preventing its dissociation and consequent deposition as amyloid fibrils in organ tissues. Tafamidis reduces mortality and the incidence of hospitalization for cardiovascular causes in patients with TTR amyloid (ATTR) cardiomyopathy. As ATTR cardiomyopathy is associated with a high risk of thromboembolic complications, we hypothesized that tafamidis may have a direct ancillary anti-thrombotic effect., Methods: Primary human aortic endothelial cells (HAECs) were treated with tafamidis at clinically relevant concentrations and with plasma of patients, before and after the initiation of treatment with tafamidis. The expression of TF was induced by incubation with Tumor Necrosis Factor α (TNFα). Intracellular expression of tissue factor (TF) was measured by western blot. TF activity was measured by a colorimetric assay. Gene expressions of TF were measured by quantitative polymerase chain reaction., Results: Treatment with tafamidis dose-dependently reduced the expression and activity of TNFα-induced TF. This effect was confirmed in cells treated with patients' plasma. Signal Transducer and Activator of Transcription 3 (STAT3) phosphorylation was significantly inhibited by tafamidis. Incubation of HAECs with tafamidis and the STAT3 activator colivelin partially rescued the expression of TF., Conclusions: Treatment with tafamidis lowers the thrombotic potential in human primary endothelial cells by reducing TF expression and activity. This previously unknown off-target effect may provide a novel mechanistic explanation for the lower number of thromboembolic complications in ATTR cardiomyopathy patients treated with tafamidis., Competing Interests: Declaration of competing interest Prof. Camici is coinventor on the International Patent WO/2020/226993 filed in April 2020; the patent relates to the use of antibodies which specifically bind interleukin-1a to reduce various sequelae of ischemia-reperfusion injury to the central nervous system. Prof. Camici is a consultant to Sovida solutions limited. Prof. Camici is the recipient of a Sheikh Khalifa's Foundation Assistant Professorship at the Faculty of Medicine, University of Zurich. Dr. Ministrini has received financial support from the Swiss Heart Foundation. Dr. Puspitasari is the recipient of a Forschungskredit Candoc grant from the University of Zurich and a grant from Swiss Life Foundation for Public Health and Medical Research. PD Dr. Stämpfli is has received travel grants, speaker fees, consulting fees, or proctoring fees from Abbott, Alnylam, Amgen, AstraZeneca, Bristol-Myers Squibb, Daiichi-Sankyo, Edwards, Polares Medical, Pfizer, and Takeda. Dr. Elliott reports personal fees from Pfizer and Alnylam, outside the submitted work. Dr. Cannie is the recipient of a British Heart Foundation Clinical Research Training Fellowship (FS/CRTF/20/24022). Prof. Hock is Medical Officer, Director and shareholder of Neurimmune AG. Dr. Kahr is Senior Medical Director at Neurimmune AG. Prof. Lüscher holds leadership positions at the European Society of Cardiology, Swiss Heart Foundation, and the Foundation for Cardiovascular Research – Zurich Heart House. TFL received institutional educational and research grants outside this work from Abbott, Amgen, AstraZeneca, Boeringer Ingelheim, Daichi—Sankyo, Menarini Foundation, Novartis, Novo Nordisk, Roche Diagnostics, Sanofi, and Vifor and honoraria from Amgen, Dacadoo, Daichi-Sankyo, Menarini Foundation, Novartis, Novo Nordisk, Philips and Pfizer. The other Authors have no competing interest to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Few reports describe the yield of postmortem genetic testing from medical examiners' offices or correlate genetic test results with autopsy-confirmed phenotypes from a large cohort., Objectives: To report results from cardiomyopathy- and cardiac arrhythmia-associated genetic testing in conjunction with autopsy findings of cases investigated at the United States' largest medical examiner office., Methods: Postmortem cases tested from 2015 to 2022 with a cardiomyopathy- and cardiac arrhythmia-associated gene panel were reviewed. American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines were used to classify variant pathogenicity. Correlations of pathogenic/likely pathogenic variants (P/LPVs) with cardiac pathology were evaluated., Results: The cohort included 1107 decedents of diverse ages and ethnicities. P/LPVs were detected in 87 (7.9%) cases, with 73 and 14 variants in cardiomyopathy and cardiac arrhythmia genes, respectively. Variants of uncertain significance were detected in 437 (39.5%) cases. The diagnostic yield (percentage of P/LPV) in decedents with cardiomyopathy (26.1%) was significantly higher than those without (P<.0001). The diagnostic yield was significantly lower in infants (0.7%) than older age groups (ranging from 1 to 74 years old, 5.7%-25.9%), which had no statistical difference between their yields. The diagnostic yields by cardiac autopsy findings were 54.0% for hypertrophic cardiomyopathy, 47.1% for arrhythmogenic cardiomyopathy, 20.0% for myocardial fibrosis, 19.0% for dilated cardiomyopathy, and 11.3% for myocarditis. Most P/LPVs were in MYBPC3, TTN, PKP2, SCN5A, MYH7, and FLNC. Ten P/LPVs were novel., Conclusions: Our results support the importance of performing postmortem genetic testing on decedents of all ages with cardiomyopathy, cardiac lesions insufficient to diagnosis a specific cardiomyopathy (e.g., myocardial fibrosis), and myocarditis. Combined postmortem cardiac examination and genetic analysis are advantageous in accurately determining the underlying cause of death and informing effective clinical care of family members., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Necroptosis, necrosis characterized by RIPK3-MLKL activation, has been proposed as a mechanism of doxorubicin (DOX)-induced cardiomyopathy. We showed that rapamycin, an mTORC1 inhibitor, attenuates cardiomyocyte necroptosis. Here we examined role of MLKL in DOX-induced myocardial damage and protective effects of rapamycin. Cardiomyopathy was induced in mice by intraperitoneal injections of DOX (10 mg/kg, every other day) and followed for 7 days. DOX-treated mice showed a significant decline in LVEF assessed by cardiac MRI (45.5 ± 5.1% vs. 65.4 ± 4.2%), reduction in overall survival rates, and increases in myocardial RIPK3 and MLKL expression compared with those in vehicle-treated mice, and those changes were prevented by administration of rapamycin (0.25 mg/kg) before DOX injection. In immunohistochemical analyses, p-MLKL signals were detected in the cardiomyocytes of DOX-treated mice, and the signals were reduced by rapamycin. Mlkl +/- and Mlkl -/- mice were similarly resistant to DOX-induced cardiac dysfunction, indicating that a modest reduction in MLKL level is sufficient to prevent the development of DOX-induced cardiomyopathy. However, evidence of cardiomyocyte necrosis assessed by C9 immunostaining, presence of replacement fibrosis, and electron microscopic analyses was negligible in the myocardium of DOX-treated mice. Thus, MLKL-mediated signaling contributes to DOX-induced cardiac dysfunction primarily by a necrosis-independent mechanism, which is inhibitable by rapamycin., (Copyright © 2024 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)