Circulation

BackgroundSepsis-induced myocardial dysfunction is a common and critical complication of sepsis. Extracellular vesicles (EVs) from clonally expanded immortalized mesenchymal stromal cells (ciMSCs) contain microRNAs that may be exploited as therapy. MethodsIn mouse models of septic cardiomyopathy induced by caecum ligation and puncture, cardiac function was determined by invasive and echocardiographic assessment. Primary cardiomyocytes derived from foetal murine and human adult ventricular tissue, as well as murine hearts were used for mechanistic studies. Studies using post-mortem human hearts or patient plasma, and clinical and echocardiographic measurements were used to establish translational relevance. ResultsIn preclinical models of sepsis, intravenous administration of either MSCs or ciMSC-EVs, given after the induction of sepsis, prevented a decrease in myocardial ejection fraction, ventricular inflammation, and mortality compared to placebo or platelet-derived control EVs. EV-microRNA sequencing identified enrichment for microRNA-187a-3p (miR-187) in ciMSC-EVs. miR-187 is anti-inflammatory; with interleukin-6 (IL-6) as its major target. Intravenous delivery of lipid nanoparticle (LNP) encapsulated miR-187 improved cardiac function, reduced inflammation, and enhanced survival of septic mice. In cardiomyocytes and in murine hearts, LNP-miR-187 reduces inflammation and expression of myocardial transcription factors linked to fetal gene reactivation in failing septic hearts. In human septic hearts, low circulating miR-187 levels correlate with reduced cardiac function and high sequential organ failure assessment (SOFA) scores. ConclusionThese findings support the development of first-in-class, cell-free, miRNA-based therapy as a novel approach to treat sepsis-induced cardiomyopathy to address a critical gap in sepsis care. One Sentence SummarymiR-based therapy for sepsis The Clinical PerspectiveA. What is NEW? Sepsis accounts for 1 in 5 deaths worldwide. Here, we demonstrate that sepsis-induced myocardial dysfunction represents a discrete, targetable sepsis-trait -- a distinct biological abnormality characterized by cardiomyocyte inflammation and fetal gene reactivation. This component contributes to the propagation of organ dysfunction and overall mortality and may respond to focused epigenetic-based interventions. B. What are the Clinical implications? Currently, there are no effective treatments to reduce, limit, or reverse the immune dysfunction component of sepsis that contributes to multiorgan failure, such as sepsis-induced cardiomyopathy. We identify miR-187 as a clinically relevant post-transcriptional regulator of cardiac inflammation and cardiomyocyte gene expression. Intravenous delivery of miR-187 encapsulated in a lipid nanoparticle (LNP) represents a fundamentally distinct, effective and pathogen-agnostic approach to correcting sepsis-induced cardiac dysfunction through modulation of cardiomyocyte inflammatory and metabolic pathways.

BackgroundPost-cardiac arrest syndrome (PCAS) is characterized by a robust inflammatory response that contributes to significant morbidity and mortality among patients resuscitated from sudden cardiac arrest (SCA). Mitochondrial DNA (mtDNA), with its bacterial-like genomic motifs, has been implicated as a damage-associated molecular pattern in other inflammatory contexts, but its role as a pro-inflammatory stimulus in PCAS has not been studied. Accordingly, the present study was designed to determine if PCAS is characterized by a rise in circulating mtDNA and, if so, whether mtDNA is selectively released, how it activates immune cells, and if targeting mtDNA-sensing pathways attenuates leukocyte activation. MethodsPlasma mtDNA and nuclear DNA (nucDNA) levels were measured in peripheral blood samples collected [~]4-hours post-ROSC from swine with PCAS (n=8) and patients hospitalized after resuscitation from out-of-hospital cardiac arrest (OHCA; n= 57). Additionally, in vitro studies were performed where porcine peripheral blood mononuclear cells (PBMCs) were treated with mtDNA or extracellular vesicles (EVs) isolated from post-ROSC plasma. Pharmacological inhibitors were utilized to inhibit toll-like receptor 9 (TLR9)- and cyclic GMP-AMP synthase (cGAS)-mediated mtDNA sensing. ResultsA significant [~]250-fold elevation in circulating mtDNA was observed shortly after ROSC in swine despite negligible changes in circulating nucDNA, suggesting selective release of mtDNA in PCAS. This finding was corroborated in human OHCA survivors, in which circulating mtDNA was similarly elevated during the early post-ROSC period. Circulating mtDNA was largely encapsulated within EVs in swine and humans, suggesting a conserved mechanism of release across species. In vitro studies demonstrated that PBMC internalization of mtDNA-containing-EVs was required for immune activation and promoted development of a pro-inflammatory leukocyte phenotype characterized by altered surface marker expression and increased release of TNF, IL-1{beta}, and IL-6. Disrupting EVs or degrading enclosed DNA attenuated these responses, which were partially restored upon reintroduction of mtDNA. Pharmacological blockade of TLR9 or cGAS pathways significantly reduced mtDNA-induced inflammation, providing insight regarding signaling pathways that may be targeted to modulate mtDNA-mediated immune activation in PCAS. ConclusionsThese novel findings demonstrate that brief whole-body ischemia and reperfusion in the context of resuscitation from SCA triggers selective mtDNA release, primarily within EVs, that acts as a potent driver of immune activation in PCAS. By linking EV-encapsulated mtDNA to TLR9 and cGAS activation, this study provides a foundation for the development of novel therapeutic interventions aimed at limiting mtDNA release or disrupting its downstream sensing pathways to enhance survival and improve outcomes after SCA. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIOur study reveals that circulating mitochondrial DNA (mtDNA), primarily encapsulated in extracellular vesicles (EV), is selectively released into the bloodstream after resuscitation from sudden cardiac arrest. C_LIO_LIEV-encapsulated mtDNA triggers immune cell activation, evidenced by phenotypic shifts toward inflammatory dendritic cells and macrophages, as well as increased pro-inflammatory cytokine secretion. C_LIO_LIPharmacological inhibition of TLR9 and cGAS pathways significantly attenuates the mtDNA-induced inflammatory response, pointing to novel therapeutic avenues for modulating post-resuscitation immune activation in patients with post-cardiac arrest syndrome (PCAS). C_LI What are the clinical implications?O_LIIdentification of mtDNA as a key driver of sterile inflammation in PCAS highlights a potential target for interventions aimed at reducing multi-organ damage and improving neurological outcomes. C_LIO_LITherapeutic strategies to block mtDNA release or downstream signaling (e.g., TLR9/cGAS inhibition) may limit harmful pro-inflammatory cascades and bolster long-term survival following resuscitation from cardiac arrest. C_LIO_LIEarly clinical screening for elevated EV-encapsulated mtDNA could help refine prognostic evaluations, complement current biomarkers, and guide personalized therapy to lessen the inflammatory burden of PCAS. C_LI

BACKGROUNDAficamten is a next-in-class, oral, selective cardiac myosin inhibitor approved for the treatment of obstructive hypertrophic cardiomyopathy (oHCM). A comprehensive understanding of long-term safety is essential to inform clinical use. OBJECTIVETo assess the integrated safety profile of aficamten across phase 2/3 clinical trials in patients with oHCM. METHODSThis integrated safety analysis pooled data from patients with oHCM who received [&ge;]1 dose of aficamten or placebo/metoprolol in REDWOOD-HCM, SEQUOIA-HCM, MAPLE-HCM, and FOREST-HCM. Safety outcomes included treatment-emergent adverse events (TEAEs), serious TEAEs, adverse events of special interest, occurrences of site-read left ventricular ejection fraction (LVEF) <50%, and echocardiography-guided treatment modifications. Events were summarized descriptively and using exposure-adjusted incidence rates (EAIRs) per 100-patient-years. RESULTSThe cumulative aficamten-treated pool included 463 unique patients, representing 697 patient-years of exposure. Aficamten was well tolerated, with permanent treatment discontinuation occurring in 4 (0.9%) aficamten-treated patients (EAIR 0.6). In the control group pool, rates of TEAEs were comparable between aficamten and placebo/metoprolol, except hypertension was more common in aficamten-treated patients. In the cumulative aficamten-treated pool, LVEF <50% occurred in 19 (4.1%) patients (EAIR 2.8). There were no cases of LVEF <50% associated with clinical heart failure that were attributable to aficamten, and no excursions of LVEF <40%. New-onset atrial fibrillation was uncommon (EAIR 2.4). CONCLUSIONSOver nearly 700 patient-years of exposure, aficamten was well tolerated with a favorable safety profile in patients with oHCM. The rates of clinically relevant systolic dysfunction, atrial fibrillation, and other major cardiovascular events were low and similar to placebo or metoprolol. Clinical trial registrationREDWOOD-HCM (NCT04219826); SEQUOIA-HCM (NCT05186818); MAPLE-HCM (NCT05767346); FOREST-HCM (NCT04848506)

Myocardial injury may ultimately lead to adverse ventricular remodeling and development of heart failure (HF), which is a major cause of morbidity and mortality worldwide. Given the slow pace and substantial costs of developing new therapeutics, drug repurposing is an attractive alternative. Studies of many organs, including the heart, highlight the importance of the immune system in modulating injury and repair outcomes. Glatiramer-acetate (GA) is an immunomodulatory drug prescribed for patients with multiple sclerosis. Here we report that short-term GA treatment improves cardiac function and reduces scar area in a mouse model of acute myocardial infarction, as well as in a rat model of ischemic HF. We provide both in vivo and in vitro mechanistic evidence indicating that in addition to its immunomodulatory functions, GA exerts beneficial pleiotropic effects, including cardiomyocyte protection and enhanced angiogenesis, mediated partially by extracellular vesicles carrying a pro-reparative cargo. Finally, as GA is a widely used drug with established efficacy and safety history, we conducted a small, prospective, randomized trial to determine its effect on patients admitted to the hospital with acute decompensated HF (ADHF). Strikingly, a short-term add-on administration of GA, resulted in marked reduction in the cytokine surge and NT-proBNP levels, both associated with acute HF exacerbations. Overall, these findings demonstrate the efficacy of GA in attenuating acute myocardial injury and modulating the inflammatory process in animal models and humans and highlight the potential of GA as a future therapy for a myriad of heart diseases. One Sentence SummaryGlatiramer acetate promotes reparative processes in rodent models of cardiac injury and reduces the inflammatory process in ADHF patients.

Dilated cardiomyopathy (DCM), an incurable disease of the cardiomyocyte terminating in systolic heart failure (HFrEF), is prevalent, causes hospitalization and is associated with increased mortality. Despite evidence of immune activation in DCM, anti-inflammatory interventions so far did not prove to alter the course of this disease. Here we show that myeloperoxidase (MPO), the principal heme peroxidase expressed by polymorphonuclear neutrophils (PMN) and monocytes, critically contributes to HFrEF in DCM. Muscle LIM protein (MLP) deficient mice, which spontaneously develop DCM, display increased circulating PMN counts and augmented levels of vessel-immobilized MPO. Genetic ablation and pharmacological inhibition of MPO resulted in enhanced nitric oxide (NO) bioavailability of systemic conductance and resistance vessels, and subsequently restoration of systolic left ventricular (LV) function, whereas infusion of MPO worsened systolic LV function. When patients diagnosed for DCM were treated with an orally available MPO inhibitor, systolic LV function increased, natriuretic peptides declined, and functional status improved. Impairment of endothelial NO bioavailability by release of leukocyte-derived MPO evolves as a disease-aggravating mechanism in DCM. MPO inhibition profoundly improved ventricular function by lowering systemic vascular resistance and thus holds promise as a novel and complementary treatment strategy for patients with DCM.

BACKGROUNDDisruption of mitochondrial homeostasis drives cardiomyopathy and heart failure, yet upstream regulatory mechanisms remain poorly defined. Neddylation, a reversible post-translational conjugation of the ubiquitin-like protein NEDD8 by E1/E2/E3 enzymes, is essential for cardiac morphogenesis, but its role in the adult heart is unknown. METHODSWe assessed the relevance of neddylation to human cardiac disease by gene set enrichment analysis of ischemic (ICM) and non-ischemic cardiomyopathy (NICM) datasets and by immunoblotting and qPCR of ventricular tissue from patients with ICM or dilated cardiomyopathy (DCM). In adult mice, we induced cardiomyocyte-restricted deletion of the NEDD8-activating enzyme 1 (NAE1) by tamoxifen injection and monitored cardiac function at baseline and after transverse aortic constriction (TAC). Bulk RNA-seq 4 weeks post-tamoxifen was combined with bioenergetic, biochemical, and ultrastructural analyses. To assess mitochondrial dynamics, we generated NAE1/MFN2 and NAE1/DRP1 double-knockout mice. Cullin activity, mitochondrial ubiquitination, and mitophagy were measured in hearts and cultured cardiomyocytes. RESULTSNeddylation pathways were dysregulated in human ICM and NICM datasets and in failing ICM/DCM myocardium. Cardiomyocyte-specific NAE1 deletion caused systolic dysfunction and heart failure by 10 weeks post-tamoxifen, culminating in premature death and exacerbating TAC-induced pressure-overload heart failure. At 4 weeks, NAE1 loss repressed metabolic and mitochondrial bioenergetic programs, reduced ATP production, and impaired respiration. Electron microscopy revealed elongated mitochondria and accumulated mitophagic vesicles, with dysregulation of DRP1, MFN2, PINK1, LC3-II, and p62. DRP1/NAE1 co-deletion accelerated systolic failure relative to either single knockout, whereas MFN2/NAE1 co-deletion did not alter early disease progression, implicating pathogenic mitochondrial hyperfusion. Genetic NAE1 depletion in vivo and pharmacologic NAE1 inhibition in vitro impaired mitophagic vesicle formation and flux, inactivated cullin scaffold proteins, reduced mitochondrial ubiquitination, and blunted mitophagic clearance. CONCLUSIONSCardiac neddylation preserves adult heart function by coordinating mitochondrial fusion-fission dynamics and sustaining cullin-dependent ubiquitination and turnover of damaged mitochondria. These findings identify neddylation as a key regulator of mitochondrial quality control and link its disruption to human cardiomyopathy. Therapeutically, targeting the neddylation-cullin axis may limit mitochondrial dysfunction, enhance mitophagy, and improve energetic reserve in failing hearts, while neddylation signatures in patient myocardium may help guide stratification and precision therapy for cardiomyopathy. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABS* Demonstrates for the first time that the NEDD8-activating enzyme (NAE1)driven neddylation pathway is indispensable for maintaining mitochondrial quality control in the adult heart. * Links loss of neddylation to mitochondrial hyperfusion, impaired mitophagy, and rapid progression to heart failure. * Reveals that neddylation promotes cullin-RING ligase-mediated ubiquitination of damaged mitochondria, coupling mitochondrial dynamics with turnover. What Are the Clinical Implications?* Restoring or enhancing cardiac neddylation may represent a novel therapeutic avenue for cardiomyopathies characterized by mitochondrial dysfunction. * Pharmacologic agents that bolster DRP1-dependent fission or activate cullin neddylation could potentially normalize mitochondrial dynamics and improve myocardial energetics. * Conversely, systemic neddylation inhibitors now in oncology trials warrant careful cardiac monitoring, as they may precipitate mitochondrial injury and heart failure. * Circulating or tissue markers of neddylation might help stratify patients at heightened risk for mitochondrial-driven cardiac disease and guide precision therapy.

BackgroundHeterozygous familial hypercholesterolemia (HeFH) is a genetic disorder characterized by persistently elevated low-density lipoprotein cholesterol (LDL-C) levels, leading to an increased risk of early-onset atherosclerosis cardiovascular diseases (ASCVD). YOLT-101, an in vivo base-editing therapeutic agent delivered via GalNAc-modified lipid nanoparticles, is designed to achieve permanent inactivation of proprotein convertase subtilisin/kexin type 9 (PCSK9), enabling sustained LDL-C reduction. MethodsThis trial enrolled participants with heterozygous genetic mutations in the low-density lipoprotein receptor (LDLR), and LDL-C levels of [&ge;]2.6 mmol/L (without ASCVD) or [&ge;]1.8 mmol/L (with ASCVD) despite receiving moderate- or high-intensity statin therapy. Eligible patients received a single intravenous infusion of YOLT-101 at ascending doses (0.2, 0.4, and 0.6 mg/kg). We report interim results from an ongoing clinical trial evaluating the safety, tolerability, pharmacodynamics, and efficacy of YOLT-101. ResultsSix participants were enrolled (median age, 48 years, range, 34-62) in the study. The most common adverse events (AEs) were transient infusion-related reactions (83.3%) and elevations in alanine/aspartate aminotransferase (50%). No study withdrawals or AEs of grade 3 or higher occurred. PCSK9 and LDL-C levels decreased in a dose-dependent manner following YOLT-101 administration. In the 0.6mg/kg group (n=3), mean PCSK9 levels decreased by 55.9% at week 1 and by 75.8% and 72.5% after 1 and 4 months, respectively; corresponding LDL-C reductions were 33.2%, 48.9%, and 50.4%, respectively. ConclusionsA single infusion of YOLT-101 at 0.6 mg/kg was well tolerated and led to sustained PCSK9 and LDL-C reduction, demonstrating promise for future clinical development. (Funded by YolTech Therapeutics; Registration Number: NCT06458010)

BackgroundChronic inflammation predicts adverse cardiovascular outcomes, but mechanisms linking systemic inflammation to cardiac remodeling remain incompletely understood. We investigated associations between circulating inflammatory biomarkers and cardiac phenotypes in a population-based cohort and examined how environmental exposures and genetic susceptibility influence inflammatory responses. MethodsWe analyzed subsets of 488,079 UK Biobank participants with metabolomic and proteomic profiling, cardiac magnetic resonance (CMR) imaging, and longitudinal outcomes. Chronic inflammation was quantified using glycoprotein acetyls (GlycA) by nuclear magnetic resonance spectroscopy. Machine learning-based analysis extracted CMR phenotypes. Multivariable linear regression assessed GlycA-cardiac associations. Mediation analysis tested 80 inflammatory proteins as potential mediators. Cox models evaluated GlycA levels and major adverse cardiovascular events (MACE). An exposome-wide association study identified environmental determinants of inflammation, and gene-environment interactions were assessed using multi-ancestry polygenic risk scores. ResultsHigher GlycA levels were associated with restrictive cardiac remodeling: reduced left ventricular indexed end-diastolic volume ({beta} = -2.09) and stroke volume ({beta} = -1.12) with compensatory increased heart rate ({beta} = 1.38; all P < 10-228). Interleukin (IL) -1 receptor antagonist mediated 27% of the GlycA effect on end-diastolic volume (average causal mediated effect -0.51 [95% CI, -0.53 to -0.64]; P < 10-16). The highest GlycA quintile had 43% higher MACE risk versus the lowest (adjusted HR, 1.43 [95% CI, 1.38-1.49]). Trunk fat mass ({beta} = 0.35), current smoking ({beta} = 0.39), psychological distress, and low socioeconomic status were the strongest GlycA determinants (all P < 10-50). Cardiovascular polygenic risk scores modified associations between environmental exposures, inflammation, and MACE. ConclusionsChronic systemic inflammation is associated with restrictive cardiac remodeling and increased cardiovascular risk mediated by circulating cytokines and growth factors. Individual inflammatory responses are shaped by gene-environment interactions, highlighting the complex interplay between genetic susceptibility, environmental exposures, and their cumulative impact on cardiovascular health.

BackgroundCardiovascular and cerebrovascular risks of SARS-CoV-2 infection and mRNA vaccination remain incompletely defined and lacking comparative outcomes such as sex-specific vulnerabilities. MethodsUsing the TriNetX Research Network (December 2020-December 2024), we identified four mutually exclusive cohorts: uninfected/unvaccinated (naive), infected/unvaccinated, vaccinated-only, and infected/vaccinated (hybrid immunity). We compared 50 prespecified cardiovascular, cerebrovascular, and mortality outcomes across four pairwise cohort comparisons, with analyses stratified by sex and time of event windows (0-3, 3- 6, 6-9, and >9months). Different vaccine dosing strategies were analyzed. ResultsAmong 30.3 million individuals, infection was associated with a 4.5-fold increased mortality in males and 4.0-fold in females (p<0.001) as well as marked increases in myocarditis, myocardial infarction, and pulmonary embolism. Inflammatory cardiac complications occurred four times more often after infection than vaccination. Vaccination alone conferred a 76% reduction in major adverse cardiovascular events (MACE) in males and 69% in females, with no detectable cardiovascular toxicity. Post-infection vaccination provided an additional 36-38% MACE reduction, though males with hybrid immunity had a late increased risk of pericarditis. Completing the two-dose vaccine series maximally reduced mortality (by 77%) and myocarditis (by 62%) versus single dosing; further doses gave minimal additional benefit but sustained the benefit of the primary vaccination series. Females had higher infection-linked myocarditis risk despite lower mortality. ConclusionsSARS-CoV-2 infection confers substantially greater and sustained cardiovascular and cerebrovascular risk than mRNA vaccination, confirming a highly favorable benefit-risk profile for vaccination. These findings support extended cardiovascular surveillance after infection and targeted, risk-based vaccination strategies.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) and autism spectrum disorder (ASD) are increasingly recognized as comorbid conditions, yet their shared molecular mechanisms remain unclear. This study investigates a novel RyR2-R169P mutation identified in a patient diagnosed with both CPVT and ASD, hypothesizing that this mutation drives calcium (Ca2+) dysregulation in cardiac and neuronal cells. Using patient-derived induced pluripotent stem cells, we generated ventricular-like cardiomyocytes and midbrain neurons. In cardiomyocytes, the RyR2-R169P mutation increased diastolic Ca2+ leak, elevated single-channel open probability, and induced arrhythmogenic Ca2+ waves under {beta}-adrenergic stress. Similarly, neurons exhibited abnormal cytosolic Ca2+ levels, enlarged soma size, and a clear trend to disrupted neurotransmitter release, including reduced GABA and elevated L-DOPA and serotonin. RyR2 biochemical analysis showed reduced phosphorylation of RyR2 by CaMKII, increased PKA dependent phosphorylation and dissociation of calstabin2 in neurons. Pharmacological stabilization of RyR2 with S107 normalized Ca2+ handling in both cell types, restored neuronal morphology, and prevented calstabin2 depletion and CaMKII phosphorylation increase. S107 restores normal neurotransmitter release only when treatment starts before neuronal differentiation. Structural modeling revealed that the R169P mutation destabilizes the N-terminal domain of RyR2, priming the channel for pathological Ca2+ leak. These findings establish RyR2-R169P as a dual regulator of Ca2+ homeostasis, directly linking cardiac arrhythmogenesis to neurodevelopmental deficits. Our results highlight RyR2 dysfunction as a shared mechanism in CPVT-ASD comorbidity and propose Rycals as a promising therapeutic candidate for mitigating Ca2+-driven pathologies in both tissues. This work demonstrates the importance of RyR2 functional integrity in neurodevelopmental processes. One Sentence SummaryNovel RyR2-R169P mutation causes calcium leak in hiPSC-derived cardiomyocytes and neurons, linking CPVT to autism via RyR2 dysfunction.

BackgroundTherapies for pediatric idiopathic dilated cardiomyopathy (iDCM) are extrapolated from adult heart failure despite limited efficacy, suggesting fundamental biological differences. Our prior transcriptomic studies indicate activation of developmental signaling pathways, including Notch and WNT, in pediatric iDCM; however, their mechanistic contribution remains unknown. We tested whether reactivation of Notch and WNT/{beta}-catenin signaling drives pathological remodeling in postnatal hearts and whether pathway inhibition improves cardiac function. MethodsWe developed a juvenile rat model to reproduce age-dependent molecular features of pediatric iDCM using {beta}-adrenergic stimulation (isoproterenol, ISO) and secreted frizzled-related protein-1 (sFRP1), a circulating WNT modulator elevated in children with DCM. Cardiac function was assessed by echocardiography; pathway activation by immunoblotting and transcriptomics; myocardial stiffness by atomic force microscopy. Findings were compared with explanted pediatric and adult human myocardium. ResultsExplanted pediatric, but not adult iDCM hearts exhibited increased nuclear and cytoplasmic Notch intracellular domain (NICD) and {beta}-catenin. Combined ISO and sFRP1 treatment recapitulated key features of pediatric disease, including ventricular dilation, reduced ejection fraction, reactivation of the fetal gene program, and increased myocardial stiffness in the absence of fibrosis or hypertrophy. Bulk and single-nucleus RNA sequencing identified cardiomyocyte-specific activation of Notch and WNT pathways and reduced intercellular signaling diversity. Mechanistically, {beta}-catenin silencing attenuated Notch target gene activation and pathological remodeling in vitro. Pharmacologic Notch inhibition reduced NICD and {beta}-catenin accumulation, improved ventricular function, and normalized myocardial stiffness in vivo. ConclusionPediatric iDCM is characterized by pathological co-activation of developmental Notch-WNT signaling pathways that are not observed in adult disease. Reactivation of this axis promotes maladaptive remodeling and myocardial stiffening, and its inhibition improves cardiac function. These findings establish developmental signaling reactivation as a central mechanism of pediatric iDCM and support age-specific therapeutic strategies.

BackgroundEpidemiological studies have consistently associated cytomegalovirus (CMV) seropositivity with adverse cardiovascular outcomes. However, the mechanisms by which CMV infection impacts pathophysiological mechanisms in the heart remain poorly understood. In this study, we sought to dissect how latent murine CMV infection impacts cardiac immune cell dynamics at steady-state and during post-myocardial infarction (MI) repair. MethodsExperimental MI studies were conducted in C57BL/6J mice previously infected with murine CMV (MCMV). In situ inflammatory responses were characterized by spectral flow cytometry, bulk and single-cell RNA / T cell receptor sequencing, whereas cardiac function was monitored by echocardiography and magnetic resonance imaging (cMRI). Moreover, we retrospectively assessed the CMV serostatus in a well-characterized patient cohort with longitudinal cMRI data available and performed bulk T cell receptor sequencing on peripheral blood and myocardial samples to identify CMV-specific TCRs. ResultsOur findings show that exposure to MCMV induces long-term changes in the cardiac transcriptional profile and alterations in cardiac-resident immune cell populations, including the establishment of virus-specific memory CD8+ T cell residency. Compared to infarcted controls, mice previously exposed to MCMV exhibited stronger inflammatory responses, marked by increased CD8+ T cell infiltration, and worsened cardiac function following MI. These observations in mice were supported by data from CMV-seropositive MI patients, who harbored CMV-responsive T cells in the heart. ConclusionsOur findings demonstrate that latent CMV infection leads to long-term changes in the cardiac microenvironment, which ultimately impair post-MI healing outcomes.

BackgroundInterleukin 11 (IL11) was initially thought important for platelet production, which led to recombinant IL11 being developed as a drug to treat thrombocytopenia. IL11 was later found to be redundant for haematopoiesis and its use in patients is associated with unexplained cardiac side effects. Here we identify previously unappreciated and direct cardiomyocyte toxicities associated with IL11 therapy. MethodsWe injected recombinant mouse lL11 (rmIL11) into mice and studied its molecular effects in the heart using immunoblotting, qRT-PCR, bulk RNA-seq, single nuclei RNA-seq (snRNA-seq) and ATAC-seq. The physiological impact of IL11 was assessed by echocardiography in vivo and using cardiomyocyte contractility assays in vitro. To determine the activity of IL11 specifically in cardiomyocytes we made two cardiomyocyte-specific Il11ra1 knockout mouse models using either AAV9-mediated and Tnnt2-restricted (vCMKO) or Myh6 (m6CMKO) Cre expression and an Il11ra1 floxed mouse strain. In pharmacologic studies, we studied the effects of JAK/STAT inhibition on rmIL11-induced cardiac toxicities. ResultsInjection of rmIL11 caused acute and dose-dependent impairment of left ventricular ejection fraction (saline (2 {micro}L/kg), 60.4%{+/-}3.1; rmIL11 (200 mcg/kg), 31.6%{+/-}2.0; p<0.0001, n=5). Following rmIL11 injection, myocardial STAT3 and JNK phosphorylation were increased and bulk RNA-seq revealed upregulation of pro-inflammatory pathways (TNF, NF{kappa}B and JAK/STAT) and perturbed calcium handling. SnRNA-seq showed rmIL11-induced expression of stress factors (Ankrd1, Ankrd23, Xirp2), activator protein-1 (AP-1) transcription factor genes and Nppb in the cardiomyocyte compartment. Following rmIL11 injection, ATAC-seq identified epigenetic enrichment of the Ankrd1 and Nppb genes and stress-responsive, AP-1 transcription factor binding sites. Cardiomyocyte-specific effects were examined in vCMKO and m6CMKO mice, which were both protected from rmIL11-induced left ventricular impairment and molecular pathobiologies. In mechanistic studies, inhibition of JAK/STAT signalling with either ruxolitinib or tofacitinib prevented rmIL11-induced cardiac dysfunction. ConclusionsInjection of IL11 directly activates JAK/STAT3 in cardiomyocytes to cause acute heart failure. Our data overturn the earlier assumption that IL11 is cardioprotective and explain the serious cardiac side effects associated with IL11 therapy, which questions its continued use in patients. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIInjection of IL11 to mice causes acute and dose-dependent left ventricular impairment C_LIO_LIIL11 activates JAK/STAT3 in cardiomyocytes to cause cell stress, inflammation and impaired calcium handling C_LIO_LIThese data identify, for the first time, that IL11 is directly toxic in cardiomyocytes, overturning the earlier literature that suggested the opposite C_LI What are the clinical implications?O_LIRecombinant human IL11 (rhIL11) is used as a drug to increase platelets in patients with thrombocytopenia but this has severe and unexplained cardiac side effects C_LIO_LIWe show that IL11 injection causes cardiomyocyte dysfunction and heart failure, which explains its cardiac toxicities that were previously thought non-specific C_LIO_LIThese findings have immediate translational implications as they question the continued use of rhIL11 in patients around the world C_LI

BackgroundMaintaining low levels of low-density lipoproteins (LDL) over time has the potential to substantially reduce the lifetime risk of atherosclerotic cardiovascular disease. However, the optimal timing of lowering LDL to prevent atherosclerotic cardiovascular events is unknown. MethodsWe combined evidence from Mendelian randomization studies and randomized trials to develop a causal AI algorithm to estimate the benefit of lowering LDL on the risk of major cardiovascular events (MCVE) in discrete time-units of exposure. We tested the accuracy of this algorithm among 440,371 participants randomized by nature to a partial loss-of-function (LOF) variant in the PCSK9 gene, and 46,488 participants in two large randomized trials of PCSK9 inhibitors. We then used this algorithm to estimate the benefit of lowering LDL using a once-yearly dose of an siRNA directed against PCSK9 beginning at different ages among 2.3 million men and women. ResultsThe causal AI algorithm accurately estimated the benefit of lifelong lower LDL due to partial loss-of-function of the PCSK9 gene, and the benefit of lowering LDL with a PCSK9 inhibitor starting at a mean age of 61 years, with nearly superimposable observed and predicted event curves. Lowering LDL by 36% was estimated to reduce the lifetime risk of MCVE by 57% (HR: 0.43, 95%CI: 0.39-0.47) if started at age 30, by 48% (HR: 0.52, 95%CI: 0.50-0.54) if started at age 40, by 38% (HR: 0.62, 95%CI: 0.60-0.65) if started at age 50, and by 26% (HR: 0.74, 95%CI: 0.71-0.77) if started at age 60 years. Moderate LDL lowering starting at age 40 years was estimated to have a greater benefit than more aggressively LDL lowering beginning at age 55 years, with a lower residual risk at all ages. In addition, the benefit of earlier LDL lowering persisted throughout life leading to a quantifiable legacy benefit. ConclusionsThe benefit of lowering LDL is determined by the magnitude, duration, and timing of LDL lowering. Modest sustained LDL lowering beginning in early to middle adulthood, which can be achieved with a once-yearly dose of a PCSK9 siRNA, may be the optimal strategy to prevent atherosclerotic cardiovascular events by slowing the progression of atherosclerosis.

ImportanceCarbohydrate-reduced nutrition improves multiple metabolic risk factors, but its influence on long-term cardiovascular (CV) outcomes remains uncertain. ObjectiveTo evaluate the impact of an individualized telemedicine nutrition therapy on the incidence of CV events. DesignClaims-based cohort study of adults with type 2 diabetes or obesity receiving telemedicine nutrition therapy versus a propensity score matched control group between January 1, 2016 and June 1, 2025, with a median follow-up of approximately two years. SettingThe intervention cohort, a US-based nationwide digital health clinic, received individualized telemedicine nutrition and clinical care. The matched control cohort was derived from a commercial claims database. ParticipantsAdults with type 2 diabetes or obesity and no CV events one year prior to index date. ExposureIndividualized nutrition therapy (INT) program combining telemedicine clinical care and carbohydrate-reduced nutrition counseling. Main Outcomes and MeasuresFour prespecified primary outcomes included 1) 3-point major adverse CV events (MACE), defined as nonfatal myocardial infarction, nonfatal stroke, or death from any cause; 2) 6-point MACE, adding percutaneous coronary intervention, hospitalization for heart failure or unstable angina; 3) all new-onset CV events; and 4) new-onset hypertension. Secondary outcomes included all-cause mortality, and safety outcomes related to arrhythmias. ResultsIn 4,877 participants in each cohort (mean age, 51 [SD 9.5] years; 2,939 [60.3%] female), INT was associated with reduced risk of all primary outcomes. Incidence per 1,000 person-years was 4.1 vs 9.3 for MACE-3, 5.7 vs 10.8 for MACE-6, 27.7 vs 36.9 for all new onset CV disease, and 41.8 vs 49.3 for new-onset hypertension. Hazard ratios were 0.44 (95% CI, 0.29-0.65; P <0.001) for MACE-3, 0.52 (95% CI, 0.37-0.73; P <0.001) for MACE-6, 0.70 (95% CI, 0.59-0.82; P <0.001) for all CV disease, and 0.81 (95% CI, 0.70-0.93; P <0.001) for new-onset hypertension. Conclusions and RelevanceIndividualized telemedicine nutrition therapy was associated with lower CV event incidence compared to controls, suggesting the intervention may confer cardioprotection. KEY POINTSO_ST_ABSQuestionC_ST_ABSWhat is the impact of an individualized telemedicine nutrition program on cardiovascular events? FindingsIn this claims-based cohort study, individuals receiving carbohydrate-reduced nutrition therapy had significantly reduced risk of all primary outcomes compared with matched controls: 56% lower 3-point MACE, 48% lower 6-point MACE, 30% lower risk of all new-onset cardiovascular events, and 19% lower new-onset hypertension. The risk of all-cause mortality was also directionally reduced. MeaningTelemedicine nutrition therapy was associated with favorable cardiovascular outcomes compared to usual care.

BACKGROUNDThe heart undergoes hypertrophy as a compensatory mechanism to cope with increased hemodynamic stress, and it can transition into a primary driver of heart failure. Pathological cardiac hypertrophy is characterized by excess protein synthesis. Protein translation is an energy-intensive process that necessitates an inherent mechanism to flexibly fine-tune intracellular bioenergetics according to the translation status; however, such a molecular link remains lacking. METHODSSlc25a26 knockout and cardiac-specific conditional knockout mouse models were generated to explore its function in vivo. Reconstructed adeno-associated virus was used to overexpress Slc25a26 in vivo. Cardiac hypertrophy was established by transaortic constriction (TAC) surgery. Neonatal rat ventricular myocytes were isolated and cultured to evaluate the role of SLC25A26 in cardiomyocyte growth and mitochondrial biology in vitro. RNA sequencing was conducted to explore the regulatory mechanism by SLC25A26. m1A-modified tRNAs were profiled by RNA immuno-precipitation sequencing. Label-free proteomics was performed to profile the nascent peptides affected by S-adenosylmethionine (SAM). RESULTSWe show that cardiomyocytes are among the top cell types expressing the SAM transporter SLC25A26, which maintains low-level cytoplasmic SAM in the heart. SAM biosynthesis is activated during cardiac hypertrophy, and feedforwardly mobilizes the mitochondrial translocation of SLC25A26 to shuttle excessive SAM into mitochondria. Systemic deletion of Slc25a26 causes embryonic lethality. Cardiac-specific deletion of Slc25a26 causes spontaneous heart failure and exacerbates cardiac hypertrophy induced by transaortic constriction. SLC25A26 overexpression, both before or after TAC surgery, rescues the hypertrophic pathologies and protects from heart failure. Mechanistically, SLC25A26 maintains low-level cytoplasmic SAM to restrict tRNA m1A modifications, particularly at A58 and A75, therefore decelerating translation initiation and modulating tRNA usage. Simultaneously, SLC25A26-mediated SAM accumulation in mitochondria maintains mitochondrial fitness for optimal energy production. CONCLUSIONSThese findings reveal a previously unrecognized role of SLC25A26-mediated SAM compartmentalization in synchronizing translation and bioenergetics. Targeting intracellular SAM distribution would be a promising therapeutic strategy to treat cardiac hypertrophy and heart failure. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LIAn activation of S-adenosylmethionine (SAM) biosynthesis during cardiac hypertrophy boosts a feed-forward mitochondrial translocation of its transporter SLC25A26 to shuttle excessive SAM into mitochondria. C_LIO_LISLC25A26-mediated cytoplasmic SAM containment restricts translation through inhibiting TRMT61A-mediated tRNA m1A modifications, particularly at A58 and A75, which modulates translation initiation and codon usage. C_LIO_LISLC25A26-mediated mitochondrial SAM accumulation enhances mtDNA methylation and is required for the implement of mitochondrial fission and mitophagy, therefore maintaining optimal bioenergetics. C_LIO_LICardiac-specific knockout of Slc25a26 causes spontaneous heart failure, and exacerbates transaortic constriction (TAC)-induced cardiac hypertrophy, while its overexpression rescues the hypertrophic pathologies. C_LI What Are the Clinical Implications?O_LICardiomyocyte-specific expression of SLC25A26 maintains low-level cytoplasmic SAM and contributes to the relatively low protein synthesis rate in the heart. C_LIO_LITargeting intracellular SAM distribution would be a promising therapeutic strategy to treat cardiac hypertrophy and heart failure. C_LI

ImportanceAortic stenosis (AS) is a major public health challenge with a growing therapeutic landscape, but current biomarkers do not inform personalized screening and follow-up. ObjectiveA video-based artificial intelligence (AI) biomarker (Digital AS Severity index [DASSi]) can detect severe AS using single-view long-axis echocardiography without Doppler. Here, we deploy DASSi to patients with no or mild/moderate AS at baseline to identify AS development and progression. Design, Setting, and ParticipantsWe defined two cohorts of patients without severe AS undergoing echocardiography in the Yale-New Haven Health System (YNHHS) (2015-2021, 4.1[IQR:2.4-5.4] follow-up years) and Cedars-Sinai Medical Center (CSMC) (2018-2019, 3.4[IQR:2.8-3.9] follow-up years). We further developed a novel computational pipeline for the cross-modality translation of DASSi into cardiac magnetic resonance (CMR) imaging in the UK Biobank (2.5[IQR:1.6-3.9] follow-up years). Analyses were performed between August 2023-February 2024. ExposureDASSi (range: 0-1) derived from AI applied to echocardiography and CMR videos. Main Outcomes and MeasuresAnnualized change in peak aortic valve velocity (AV-Vmax) and late (>6 months) aortic valve replacement (AVR). ResultsA total of 12,599 participants were included in the echocardiographic study (YNHHS: n=8,798, median age of 71 [IQR (interquartile range):60-80] years, 4250 [48.3%] women, and CSMC: n=3,801, 67 [IQR:54-78] years, 1685 [44.3%] women). Higher baseline DASSi was associated with faster progression in AV-Vmax (per 0.1 DASSi increments: YNHHS: +0.033 m/s/year [95%CI:0.028-0.038], n=5,483, and CSMC: +0.082 m/s/year [0.053-0.111], n=1,292), with levels [&ge;] vs <0.2 linked to a 4-to-5-fold higher AVR risk (715 events in YNHHS; adj.HR 4.97 [95%CI: 2.71-5.82], 56 events in CSMC: 4.04 [0.92-17.7]), independent of age, sex, ethnicity/race, ejection fraction and AV-Vmax. This was reproduced across 45,474 participants (median age 65 [IQR:59-71] years, 23,559 [51.8%] women) undergoing CMR in the UK Biobank (adj.HR 11.4 [95%CI:2.56-50.60] for DASSi [&ge;]vs<0.2). Saliency maps and phenome-wide association studies supported links with traditional cardiovascular risk factors and diastolic dysfunction. Conclusions and RelevanceIn this cohort study of patients without severe AS undergoing echocardiography or CMR imaging, a new AI-based video biomarker is independently associated with AS development and progression, enabling opportunistic risk stratification across cardiovascular imaging modalities as well as potential application on handheld devices.

Backround and aimsProlonged QRS duration ([&ge;] 110 ms) and coronary artery disease are risk factors for sudden cardiac death (SCD). We explored the SCD risk associated with intraventricular conduction disorders - a prolonged QRS duration of 110-119 ms, right bundle branch block (RBBB), left bundle branch block (LBBB), and a nonspecific intraventricular conduction delay (NIVCD) - in patients with acute coronary syndrome (ACS). MethodsThis is a retrospective study of 9,700 consecutive, invasively treated ACS patients with ECGs available for analysis (2007-2018). SCD definition was based on an in-depth review of written medical records and death certificates describing the circumstances leading to the events. Endpoint data were available until December 31, 2021 (no losses to follow-up). The risk associated with conduction disorders was analyzed by calculating subdistribution hazard estimates (deaths due to other causes being considered competing events). ResultsThe median follow-up time was 6.8 years (IQR 4.0-10.2), during which 3,420 (35.3%) patients died. SCDs were overrepresented as a cause of death among patients with NIVCD (16.4%) or with a prolonged QRS duration (15.3%) when compared to patients with LBBB (5.3%), RBBB (7.1%), or with a normal QRS duration (10.5%). In an analysis adjusted for age, sex, and cardiac comorbities, NIVCD and a prolonged QRS were significant predictors of SCD (HR 3.00, 2.06- 4.35, P < 0.001; and HR 1.80, 1.37-2.35, P < 0.001, respectively). After adjusting the analysis with left ventricular ejection fraction, NIVCD and a prolonged QRS duration remained as significant risk factors for SCD. LBBB and RBBB did not predict SCD. ConclusionThe incidence of SCD is significantly higher in patients with NIVCD and a prolonged QRS duration. Approximately 23% of all SCDs occur among these patients.

Background: Despite optimal lipid-lowering and antithrombotic therapy, substantial residual cardiovascular risk persists in established atherosclerotic cardiovascular disease (ASCVD), partly driven by chronic vascular inflammation. Methods: Systematic review and meta-analysis of RCTs comparing colchicine to placebo or no treatment in adults with established ASCVD. Searches on March 21, 2026 (PubMed, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP). PROSPERO CRD420261346516. Primary outcome: 4-point MACE (CV death, MI, stroke, urgent revascularization). DerSimonian-Laird random-effects with HKSJ adjustment. Exploratory trial-level meta-regression: time-to-initiation (TTI) and cumulative dose as continuous moderators. Results: DL pooled HR for 4-point MACE: 0.68 (95% CI 0.51-0.89; p=0.0060). HKSJ-adjusted HR: 0.68 (95% CI 0.27-1.70; p=0.3018). Substantial heterogeneity (I2=81.4%; 95% prediction interval 0.29-1.57, crossing 1.0). Exploratory meta-regression: TTI (beta=-0.00187/day, p=0.003) and cumulative dose (beta=-0.00163/mg-day, p=0.0003; k=5, explicitly underpowered). Non-CV mortality: HR 1.07 (0.76-1.50; p=0.694). GI discontinuation: pooled RR 1.95 (1.09-3.48; p=0.024). GRADE certainty: Moderate (4-point MACE). Conclusions: Low-dose colchicine is associated with reduced 4-point MACE in ASCVD (DL HR 0.68; HKSJ HR 0.68). The substantial heterogeneity and wide prediction interval indicate that effect size varies substantially across clinical settings. The divergence between CLEAR SYNERGY (acute; HR 0.99) and sub-acute/chronic trials (HR 0.33-0.77) drives heterogeneity. Meta-regression suggests TTI and cumulative exposure may be key moderators but is underpowered. The non-CV mortality signal is not confirmed. This analysis informs precision anti-inflammatory prescribing in ASCVD.

BACKGROUND Point-of-care (POC) high-sensitivity cardiac troponin (hs-cTn) testing has the potential to expedite decision-making and reduce emergency department (ED) length of stay for patients presenting with possible myocardial infarction (MI) by ensuring that results are consistently available when looked for by clinicians. We assessed the real-life effectiveness and safety of implementing POC hs-cTn testing in the ED. METHODS We conducted a pragmatic, stepped-wedge cluster randomized trial. The control arm was usual care with an accelerated diagnostic pathway utilizing a single-sample rule-out step with a central laboratory hs-cTn assay. The intervention arm used the same pathway with a POC hs-cTnI. The primary effectiveness outcome was ED length of stay assessed using a generalized linear mixed model, and the safety outcome was 30-day MI or cardiac death. RESULTS Six sites participated with 59,980 ED presentations (44,747 individuals, 61{+/-}19 years, 49.5% female) from February 2023 to January 2025, in which 31,392 presentations were during the intervention arm. After adjustment for co-variates associated with length of stay, the intervention reduced length of stay by 13% (95% confidence intervals [CI], 9 to 16%. P<0.001), corresponding to a reduction of 47 minutes (95%CI, 33 to 61 minutes) from a mean length of stay in the control arm of 376 minutes. The 30-day MI or cardiac death rate was similar in the control and intervention arms (0.39% and 0.39% respectively, P=0.54). CONCLUSIONS Implementation of whole-blood hs-cTnI testing at the POC into an accelerated diagnostic pathway was safe and reduced length of stay in the ED compared with laboratory testing.