Abstract 4138606: Toll-like Receptor 4 Signaling Establishes Trained Innate Immunity Through Interferon-Mediated Epigenetic Modifications Leading to Cardioprotection in a Stress-induced Cardiomyopathy Model

Circulation, Volume 150, Issue Suppl_1, Page A4138606-A4138606, November 12, 2024. Introduction:The mechanisms responsible for establishing preconditioning-induced cardioprotection remain unknown. We have shown that a high dose of isoproterenol (ISO) induces cardioprotection against a second ISO dose in mice. The durability of protection and the lack of an innate immune response suggests trained immunity as a novel cardioprotective mechanism.Hypothesis:We hypothesize that cardioprotection is conferred through trained immunity, by interferon signaling downstream of necrotic cardiac material-mediated Toll-like receptor 4 (TLR4) activation.Methods:Wild-type C57BL/6J mice were intraperitoneally injected with TLR agonists or diluent, and challenged with 300 mg/kg ISO 7 days later. Mice were assessed by 2-D echocardiography, serum cardiac troponin levels, flow cytometry immune cell counts, and Multiome (single nuclei RNA+ATAC) sequencing.Results:The TLR4 agonist lipopolysaccharide (LPS) induced cardioprotection against ISO injury, with mice having enhanced survival (P=0.049) and no changes in cardiac troponin levels (P >0.99), cardiac neutrophil influx (P >0.99) or left ventricular motion (P=0.057) relative to baseline values before injury. Treating LPS-injected mice with β-glucan reversed the effects of LPS on immune cells and abolished cardioprotection. Multiome analysis of genes linked to chromatin peaks with increased accessibility in LPS+vehicle (protected) compared to LPS+β-glucan and diluent control (non-protected) hearts revealed the interferon pathway to be up-regulated across all major cell types. Modulation of interferon signaling with monoclonal antibodies against type 1+2 interferon receptors abolished cardioprotection in LPS-treated mice, whereas pre-treatment with recombinant type 1+2 interferons induced cardioprotection. Importantly, interferon-treated hearts shared similar chromatin accessibility features and enriched transcription factor motifs, including interferon-specific motifs, with LPS-protected hearts across cell types, particularly among non-cardiomyocytes.Conclusions:TLR4-induced interferon signaling is sufficient and in part necessary for cardioprotection against ISO injury. Moreover, our findings show that epigenetic modifications downstream of interferon signaling lead to cardioprotection consistent with trained innate immunity.

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Novembre 2024

Abstract 4145256: Urban Greenspace Exposure, Stress, and Cardiovascular Function.

Circulation, Volume 150, Issue Suppl_1, Page A4145256-A4145256, November 12, 2024. Introduction:Healthy urban environments are essential for improving cardiovascular health. Although exposure to wild green surroundings has been shown to have positive effects on mental and physical health, the effect of urban greenspaces on cardiovascular function and stress remain unclear.Research Question:Does being in an urban park decrease stress and autonomic tone as reflected by heart rate variability (HRV).Methods:We invited healthy adults (n=41; age 25-70 years) to participate in a cross-over panel study. They were randomly assigned to start in either a typical urban park or an adjacent urban space, spending 20min sitting and 20min walking. Self-reported distress and State-Trait Anxiety Index (STAI) scales were assessed before and after exposure. Pairedt-test was used to compare stress levels by site, and the effect size was calculated using regression analysis after adjusting for the level of starting distress. ECG recordings were acquired for the duration of the visit. HRV epochs of 5 min at the end of sitting or walking period and 40 min for the entire study were analyzed and compared using pairedt-test.Results:Pre-exposure distress and STAI summed scores were similar for the park and built spaces, but the level of distress was lower after visiting the park compared with built space (19.6±15.0 vs. 24.1±12.1; p=0.05). STAI scores were decreased after visiting the park, but not the built space (-5.4±8.2 vs. 0.8±6.8; p=0.003). When adjusted for the starting levels of distress, the summed STAI score after visiting the park was reduced by 6 (-10.34, -2.11), but no change for the built site. The standard deviation of NN intervals (SDNN) was higher in the park than the urban site (41.7 vs. 37.3; p=0.03) and the HR was lower (78 vs. 81; p=0.01) across the entire study epoch (40min). There was no significant change during the seated portion of visits, but across the walking portion, the values of SDNN were higher in greenspace (32.2 vs. 27.0; p= 0.01) and HR was lower (87 vs 84; p=0.02). Other HRV indices were not significantly affected.Conclusion:Visiting an urban park, but not a built environment, led to a decrease in self-reported distress, and a relative shift in the autonomic nervous system towards parasympathetic dominance. Although the relationship between changes in stress and HRV remain unclear, access to greenspaces may be an important factor in maintaining and enhancing cardiovascular health in urban environments.

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Novembre 2024

Abstract 4141357: Diagnostic and prognostic value of quantitative stress perfusion CMR in the non-invasive assessment of cardiac allograft vasculopathy

Circulation, Volume 150, Issue Suppl_1, Page A4141357-A4141357, November 12, 2024. Background:Cardiac allograft vasculopathy (CAV) is a rapidly progressive form of coronary atherosclerosis limiting long-term survival after heart transplantation.Objectives:We evaluated the diagnostic and prognostic yield of quantitative stress cardiovascular magnetic resonance (CMR) perfusion for CAV detection in heart transplant recipients.Methods:Patients who received orthotopic heart transplants and underwent stress CMR for CAV assessment were included in the study and followed up for almost 2 years (median 1.8; IQR 0.9,2.7). The diagnostic accuracy of qualitative and quantitative stress CMR was assessed by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), using invasive or CT coronary angiography as the reference for CAV detection. The area under the curve (AUC) was compared for qualitative and quantitative stress CMR. Adjusted hazard ratios for major adverse cardiac events (MACE), including death and unplanned cardiac hospitalizations were derived in all patients. The global myocardial perfusion reserve index (MPRi) was obtained by normalization to the rate-pressure product.Results:In a cohort of 60 patients, n=18 (30%) had significant CAV (grade 2 or 3), and n=11 (18.3%) experienced MACE. At the Youden index threshold of 2.1, the myocardial perfusion reserve index (MPRi) demonstrated a sensitivity of 85.7%, a specificity of 70.3%, a PPV of 52.2%, and an NPV of 92.9%. The MPRi was significantly more accurate than visual assessment (p < 0.001) in identifying underlying CAV (Figure 1) and it was an independent predictor of MACE (HR:0.26;95%CI:0.07,0.93; log-rank p=0.022; Figure 2), while the visual presence of inducible myocardial perfusion defect did not (HR:2.23;95%CI:0.57,8.66; p=0.2).Conclusions:In patients with previous heart transplantation, quantitative stress CMR perfusion has incremental diagnostic and prognostic value over qualitative stress CMR for the non-invasive detection of CAV.

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Novembre 2024

Abstract 4145104: Can Stress Echocardiography during Cardiopulmonary Exercise Testing Help Predict Clinical Outcomes in Right-Sided Congenital Heart Disease?

Circulation, Volume 150, Issue Suppl_1, Page A4145104-A4145104, November 12, 2024. Background:The optimal timing for intervention for pulmonary and right ventricular outflow tract stenosis in adult congenital heart disease (ACHD) remains uncertain. While stress echocardiography is an established modality to improve risk stratification in stenotic left-sided lesions, its utility in right-sided valve disease in the ACHD population has not been studied. We assessed if stress echocardiographic assessment of right ventricular (RV) function during cardiopulmonary exercise testing (CPET) can facilitate risk stratification in the ACHD population.Objectives:The purpose of this study was to determine the relationship between RV augmentation on stress echocardiogram during CPET and morbidity in ACHD patients with sub-pulmonary right ventricles and right-sided stenotic lesions.Methods:A retrospective cohort study of ACHD patients with sub-pulmonary right ventricles who underwent CPET with stress echocardiogram was performed. The primary outcome was defined as having at least one of the following: 1) cardiac related hospitalization, 2) new documented arrhythmia, or 3) new or worsening heart failure. RV augmentation on stress echo was verified by concordance with a second observer.Results:The study included 87 patients, 41 (47%) with repaired tetralogy of Fallot, 9 (10.3%) with RV-PA conduits, and 9 (10.3%) with pulmonary stenosis. On baseline transthoracic echocardiogram, median peak pulmonary valve gradient was 38.7 mmHg (Q1 17.9 , Q3 49.0) and 30% of patients had RV dysfunction. On stress imaging, 13 (14.9%) did not demonstrate RV augmentation. Those without RV augmentation had a lower percent predicted peak Vo2 (61.4% vs 75.4%, p=0.007). Eleven (12.6%) met the primary outcome. Lack of RV augmentation was strongly associated with the primary outcome (OR 4.25, CI 1.04 –17.46, p = 0.04). This association remained true in patients with baseline peak PV gradients less than 50mmHg (OR 8.7, CI 1.68 – 46.79, p = 0.009) and was more pronounced in patients with tetralogy of Fallot (OR 33.99, CI 3.29 – 829, p = 0.007).Conclusions:Lack of RV augmentation on stress echo during CPET is associated with increased morbidity in ACHD patients with right-sided stenotic lesions. These results suggest that stress echocardiography at the time of CPET should be considered in this population.

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Novembre 2024

Abstract 4147568: Sociodemographic Disparities Associated with Stress, Cardiovascular Disease, and Cancer Outcomes in the All of Us Research Program

Circulation, Volume 150, Issue Suppl_1, Page A4147568-A4147568, November 12, 2024. Introduction:Cardiovascular disease (CVD) and cancer are among the leading causes of morbidity and mortality worldwide. Increasing evidence suggests that sociodemographic factors such as race, ethnicity, income, education, and stress levels significantly influence the prevalence and outcomes of these diseases. TheAll of UsResearch Program provides a unique opportunity to explore these disparities across a diverse U.S. population. This study aims to examine how sociodemographic disparities are associated with stress, CVD, and cancer outcomes. We hypothesize that higher perceived stress levels, lower income, lower education levels, and minority race/ethnicity groups are associated with higher incidences of CVD and cancer.Methods:Data from 55,505All of UsResearch program participants were analyzed. Key variables included age, race, ethnicity, education, household income, perceived stress level, and history of CVD and cancer. Descriptive statistics were used to summarize participant demographics. Multivariate logistic regression models were employed to examine the associations between sociodemographic factors and the outcomes of interest (CVD and cancer).Results:Older participants had a higher prevalence of both CVD (mean age: 60.8 vs. 50.5, p < 0.001) and cancer (mean age: 63.6 vs. 51.7, p < 0.001). Black/African Americans had a higher incidence of CVD (21.3% vs. 78.7%, p < 0.001), while Whites had a higher prevalence of cancer (5.3% vs. 94.7%, p < 0.001). Lower income and higher stress levels were also associated with higher CVD incidence (

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Novembre 2024

Abstract 4145174: Impact of chronic reductive stress on myocardial proteome turnover: Insights into proteotoxicity and predictive cardiac remodeling

Circulation, Volume 150, Issue Suppl_1, Page A4145174-A4145174, November 12, 2024. Background:Protein half-life and turnover are crucial for cellular function, especially under basal and stress conditions, often contributing to proteinopathies. While the impact of oxidative stress (OxS) on proteostasis is well-documented, the role of reductive stress, an overabundance of antioxidant status, in proteotoxic cardiac disease remains elusive.Hypothesis:Tested whether chronic reductive stress (cRS) impairs protein turnover and induce proteotoxic cardiac disease.Methods:In transgenic mice expressing constitutively active Nrf2 (caNrf2-TG) and non-transgenic controls (n=6/gp.), we examined the half-life and turnover rates of the myocardial proteome using D2O labeling and mass spectrometry.Results:We observed significant changes in the half-life of over 1,700 proteins, with approximately 1,200 proteins exhibiting increased half-life at 3 months, despite no noticeable defects in cardiac structure and function. Under OxS induced by isoproterenol (ISO), about 700 proteins showed reduced half-life, underscoring distinct regulatory mechanisms in protein turnover between cRS and OxS. Proteins with altered half-lives were involved in key cellular functions, including metabolism, signal transduction, immune response, transport, and cell cycle regulation under cRS, revealing novel targets undetected in an OxS context. Notably, distinct positive adaptive compensatory (59; p

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Novembre 2024

Abstract 4145408: The Unexpected Heart Stopper: A Case of Ketamine-Induced Stress Cardiomyopathy Requiring Mechanical Circulatory Support

Circulation, Volume 150, Issue Suppl_1, Page A4145408-A4145408, November 12, 2024. Background:Stress cardiomyopathy (SCM) is rarely triggered by ketamine and seldom leads to cardiogenic shock. Ketamine-induced catecholaminergic surge can lead to myocardial stunning with transient ischemia and subsequent reversible heart failure. Mechanical circulatory support can be successfully leveraged in SCM-associated cardiogenic shock while awaiting myocardial recovery.Case Presentation:A 28-year-old female with chronic pain was admitted for failure to thrive secondary to opioid-induced gastroparesis. The patient was weaned off opiates while on ketamine over 4 days. After halting ketamine, the patient had a cardiac arrest with eventual return of spontaneous circulation. After being extubated, she developed chest pain, hypotension, and ventricular tachycardia with anterolateral ST elevations, troponin leak, and lactic acidosis. TTE revealed an EF

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Novembre 2024

Abstract 4148019: Shear Stress Affects Human Aortic Endothelial Heparan Sulfate Expression Response to Inflammatory Stimulus

Circulation, Volume 150, Issue Suppl_1, Page A4148019-A4148019, November 12, 2024. Background:Heparan sulfate (HS) proteoglycans act as mechanosensors on endothelial cells (ECs), regulating EC morphology and function. HS expression is affected by culture under static or dynamic conditions. HS response to inflammatory stimulus under both conditions is not well characterized. This study investigated HS expression on human aortic ECs (HAECs) under static and arterial flow conditions.Hypothesis:Inflammation modeled by TNFa significantly decreases HS epitope on HAECs under both static and arterial flow conditions.Aims:To establish the effect of TNFa on HS expression in HAECs.Methods:Passages 4 through 8 HAECs (ATCC) were cultured to confluence in endothelial growth medium (Vasculife) in Ibitreat µ-Slide 8 well high chambered coverslip slides or Ibitreat µ-Slide VI 0.4 flow channel slides. Cells were treated with TNFa at 100 ng/mL for 3 hours under static conditions or conditioned with 10 dyn/ cm2 of shear stress for 24 hours and then treated with TNFa at the same concentration added to the circulating media for 3 hours. HAECs were fixed in 2% paraformaldehyde/ 0.1% glutaraldehyde for 30 minutes followed by blocking with 2% goat serum for 30 minutes, both at room temperature. Primary antibody to the 10E4 HS epitope was incubated at 4°C overnight (1:100; 10E4 epitope, AMS Biotechnology, USA) followed by incubation in Alexa Fluor 488 goat anti-mouse secondary antibody (1:300, Molecular Probes, USA) for 1 hour at room temperature. HAECs nuclei were stained using 4′,6-diamidino-2-phenylindole and immersed in phosphate buffered saline for confocal imaging using a laser scanning microscope (Zeiss, LSM 880, 20X).Results:TNFa significantly (p < 0.05) increased HS expression in HAEC monolayers treated under static conditions compared to untreated control and heparinase III treated HAECs (Figure 1A). HAEC monolayers conditioned under arterial shear stress expressed significantly (p < 0.05, ANOVA with Tukey’s post-hoc) higher HS levels compared to baseline static controls; however, flow conditioned HAECs did not show any difference in HS expression under untreated compared to TNFa conditions (Figure 1B).Conclusion:These data indicate that fluid shear stress may program endothelial cells to significantly alter their HS expression and response to inflammatory stimuli.

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Novembre 2024

Abstract 4132820: S-nitrosylation of cardiac Cx43 hemichannels at Cys271 promotes arrhythmogenicity and myocardial injury upon cardiac stress in Duchenne Muscular Dystrophy

Circulation, Volume 150, Issue Suppl_1, Page A4132820-A4132820, November 12, 2024. Connexin-43 (Cx43) plays a critical role in the propagation of action potentials among cardiomyocytes and proper cardiac contractility. In healthy cardiomyocytes, Cx43 is located at the intercalated disk; however, Cx43 remodeling is observed in cardiac pathologies and is linked with arrhythmogenesis and sudden cardiac death. Utilizing a mouse model of Duchenne muscular dystrophy (DMDmdx), we have previously demonstrated that cardiac Cx43 is laterally localized, forming undocked hemichannels that activate via S-nitrosylation in response to isoproterenol-evoked cardiac stress. This activation leads to the disruption of cardiac membrane permeability, triggered activity, and deadly arrhythmogenic behaviors. To establish the direct role of S-nitrosylated Cx43 in DMD cardiomyopathy, we developed a specific knock-in mouse line in which the single Cx43 site for S-nitrosylation, cysteine 271 (Cys271), was substituted with a serine (C271S+/-). Here, we developed a DMDmdx:C271S+/-line (4–6 months old), exhibiting reduced levels of S-nitrosylated Cx43 after crossing DMDmdx mice and C271S+/-mouse lines to assess the effect of β-adrenergic stimulation-induced cardiac stress and heart dysfunction. We show that cardiac Cx43 remodeling was not prevented in DMDmdx:C271S+/-, similar to what was shown in DMDmdxmice via immunofluorescence analysis. In addition, DMDmdxmice displayed an increased number of deadly arrhythmogenic events, increased Ca2+signaling, and prolonged action potentials in Langendorff-perfused whole hearts via optical mapping, compared to wild-type and DMDmdx:C271S+/-mice. Similarly, isoproterenol treatment evoked severe myocardial injury, increased levels of plasmatic cardiac troponin I (cTnI), and 40% mortality in DMDmdxmice. Notably, DMDmdx:C271S+/-mice, similar to DMDmdxmice treated with the Cx43 hemichannel blocker Gap19, exhibited cardioprotection compared to the cardiac dysfunction observed in DMDmdxmice. Therefore, these findings strongly suggest that S-nitrosylation of Cx43 proteins at site Cys271 represents a fundamental NO-mediated mechanism involved in the induction of arrhythmias and myocardial injury in DMDmdxafter β-adrenergic stress.

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Novembre 2024

Abstract 4146434: Factors Associated with Subsequent Catheterization and Identification of High-Grade Obstructive Coronary Artery Disease in Patients Without Known Coronary Disease and a Low to Moderate Short-Term Risk PET/CT Stress Test

Circulation, Volume 150, Issue Suppl_1, Page A4146434-A4146434, November 12, 2024. Background:PET/CT stress test may be performed to risk stratify patients including those without known coronary artery disease (CAD) who may be at risk for short-term adverse cardiac events. In patients with low- to moderate (LTM) risk for short-term MACE and without a known history of CAD, a small percentage of these patients will undergo a coronary angiogram within 90-days, of which some will be diagnosed with high-grade stenosis. The purpose of this study is to determine factors associated with this approach and findings.Methods:Patients without a history of known CAD (n=43,271) undergoing a PET/CT from 2018-2023 at Intermountain Health, with scan interpreted clinically as LTM short-term risk for adverse cardiac events, and ischemic burden 70% stenosis in any vessel), an a priori list of clinical data and PET/CT results were examined.Results:Within 90 days of the LTM risk PET/CT, 3,163 (8.2%) had a coronary angiogram. Of these, 806 (25.5% of angiograms and 2.1% of total LTM) had high-grade CAD. The PET/CT ancillary findings were associated with the largest odds of performing an angiogram and the presence of high-grade CAD (Tables). Factors most likely to be associated with performing an angiogram were an ischemic burden of 7.5-10% (adjusted-OR [adj. OR]=11.54), coronary artery calcification (CAC) score of >300 (adj.-OR =1.62), and myocardial blood flow (MBF) of MBF 2.3). Other clinical parameters associated, after adjustment, with an angiogram were age, male sex, hypertension, elevated troponin, and inpatient status. Many of the same factors were found to be associated with the identification of high-grade CAD. However, being an inpatient was associated with increased odds of angiogram but a decrease in odds of high-grade CAD.Conclusions:In patients without a known history of CAD who underwent PET/CT clinically adjudicated as LTM short-term risk and ischemic burden

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Novembre 2024

Abstract 4143420: Additive Prognostic Significance of Vascular Disease in Patients Referred for Exercise Stress Echocardiography

Circulation, Volume 150, Issue Suppl_1, Page A4143420-A4143420, November 12, 2024. Background:The presence of carotid plaque (CP) may serve as an indicator of panvascular atherosclerosis. However, the observed incongruity between carotid disease and the presence and severity of coronary artery disease (CAD) suggests differing mechanisms. We investigated the prognostic value of this incongruity, considering both known atherosclerosis and myocardial ischemia.Methods:In a retrospective analysis, we examined 111 patients (mean age: 64±12 years, 58% women) who underwent exercise stress echocardiography, with recent carotid artery and coronary evaluation. We computed a Vascular Disease (VasD) score, integrating the presence of carotid plaque (CP) on carotid ultrasound, known coronary artery disease (CAD), and myocardial ischemia (MyI). Subsequently, patients were followed for 5.5 years for mortality, coronary revascularization, and cardiac hospitalization.Results:During the follow-up period, 29 patients experienced the combined outcome (4 deaths, 10 revascularizations, and 22 hospitalizations). Among the cohort, 44 patients exhibited no vascular disease, while 67 displayed evidence of vascular disease, categorized as 42 with VasD of 1 (comprising 30 CP, 9 CAD, and 3 MyI), 14 with VasD of 2 (5 CP and CAD, 6 CP and MyI, 3 CAD and MyI), and 11 with VasD of 3. There were no significant differences between patients with and without VasD concerning sex, diabetes, renal function, atrial arrhythmia, baseline LVEF, and baseline diastolic function. However, patients with VasD were older, had higher H2FPEF scores, and lower exercise capacity, as well as elevated baseline and exercise-induced filling pressures. The incidence of the combined outcome showed a progressive increase with higher VasD scores (p

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Novembre 2024

Abstract 4145148: The Hypertrophic Cardiomyopathy Associated Junctophilin-2 E169K Variant Disrupts Mitofusin-2 Binding and Elicits a Pathological Cellular Response to Metabolic Stress

Circulation, Volume 150, Issue Suppl_1, Page A4145148-A4145148, November 12, 2024. Introduction:Junctophilin-2 (JPH2) plays essential roles in multiple cardiac processes including calcium handling, t-tubule structure, and gene regulation. We recently showed JPH2 also has a mitochondrial role as it binds the mitochondrial protein mitofusin-2 (MFN2) and modulates mitochondrial metabolic function. However, the impacts of JPH2 disease-causing variants on MFN2 binding and subsequent cellular responses to metabolic stressors are unknown.Methods:Disease-associated variants in the MFN2 binding domain of JPH2 were engineered and recombinantly expressed in E. coli cells. Purified proteins were then subjected to pulldown experiments to assess MFN2 protein binding. Alphafold3 modeled how MFN2 and JPH2 and JPH2 E169K mutants interacted in the presence or absence of fatty acids. Wildtype JPH2 or JPH2 E169K expression was directed by a doxycycline inducible promoter after being cloned into the AAVS1 locus in JPH2 knockout iPSC-cardiomyocytes. In vitro metabolic stress was induced by incubating iPSC-CM with 150 μM oleate, 150 μM palmitate, and 500 μM carnitine overnight. Super resolution confocal microscopy visualized mitochondria integrity, nuclei shape and size, and lipid droplet accumulation and morphology.Results:In pulldown experiments, the JPH2 E169K mutation disrupted MFN2 binding. Alphafold3-based modeling showed JPH2 E169K disrupted the interaction between the two proteins when modeled with or without lipids (A-D). Control, wild type JPH2, and JPH2 E169K iPSC-CM displayed divergent responses to in vitro metabolic stress. JPH2 E169K cells exhibited pathological mitochondrial network changes characterized by a lower mitochondrial footprint and less network branches (E-G). In addition, the JPH2 E169K iPSC-CM accumulated significantly more lipid droplets in the cytoplasm and the nucleus, and the JPH2 E169K lipid droplets were significantly larger than the other cell types (H-K). Finally, the accumulation of lipid droplets impacted nuclear morphology as the JPH2 E169K cells had nuclear hypertrophy and nuclei were more ellipse-shaped (L-N).Conclusion:The JPH2 E169K variant disrupts MFN2 binding, which results in heightened metabolic stress characterized by lipid droplet accumulation and mitochondrial and nuclear morphological changes. These results implicate a new pathophysiological mechanism for how the JPH2 E169K mutation causes cardiac dysfunction.

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Novembre 2024

Abstract 4146225: Stress Perfusion Cardiac Magnetic Resonance Imaging for Pediatric Patients with Repaired Transposition of the Great Arteries

Circulation, Volume 150, Issue Suppl_1, Page A4146225-A4146225, November 12, 2024. Introduction:Patients who underwent arterial switch operation (ASO) for d-transposition of the great arteries (TGA) are at increased risk for early myocardial ischemia. Stress perfusion cardiac MR (SPCMR) is used as a non-invasive tool for risk stratification but interpretation is often challenging.Hypothesis:There is significant interobserver variability in SPCMR image interpretation in patients with repaired TGA.Aims:1. Determine incidence and severity of adverse effects of stress agents.2. Evaluate incidence of positive SPCMR.3. Assess agreement amongst reviewers in image interpretation.Methods:Patients with repaired TGA with SPCMR imaging from 2013 to 2024 were reviewed. Three patients with previous coronary intervention and one with severe chest pain after adenosine, unable to complete SPCMR, were excluded. 61 studies were performed in 56 patients. Images were independently reviewed by two investigators blinded to initial interpretation and clinical outcome. Perfusion defects were displayed on a circumferential polar plot using standard LV segmentation.Results:Median (IQR) age was 15 (11-17) years, weight 55 (36-68) kg, and BSA 1.6 (1.2-1.8) m2. Max heart rate was 110 (100-125) and systolic BP 127 (116-138). Eleven (20%) patients had cardiac symptoms, chest pain in 9 (16%), syncope in 1 (2%), pallor and distress in 1 (2%) infant. Adverse effects from SPCMR in 8/52 (15%) adenosine, 2/4 (50%) dobutamine, and 0/6 (0%) regadenoson were minor and resolved on stress completion. Six (10%) studies were initially interpreted as suspicious (n=5) or definitive (n=1) perfusion defect (Figure). No LGE was detected. Original interpretation did not match blinded reviews for 6 cases (Figure). Blinded reviewers agreed on 3 negative cases but interpretation differed in the other 3 cases (Figure).Conclusions:SPCMR is safe and feasible. Significant interobserver variability highlights the challenges in qualitative SPCMR interpretation for TGA. Quantitative perfusion may reduce interobserver variability. Larger multicenter studies would be helpful in further elucidating the risk profile of patient characteristics and coronary artery arrangements to determine whether routine use of SPCMR is warranted for TGA patients.

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Novembre 2024

Abstract 4143635: Stress-related Sleep Disturbance Inflames Myocardial cGAS-STING Pathway through activating bone marrow macrophage

Circulation, Volume 150, Issue Suppl_1, Page A4143635-A4143635, November 12, 2024. Background/Introduction:Delayed bedtime following stress disorder is prevalent in waves of pandemics and modern life. Considered to be a specific and important contributor to cardiovascular health, stress-related sleep disturbance has an unmet need in steady preclinical models. We previously found exciting corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVH) area of mice could induce 3-hour-long wakefulness.Methods:The chemogenetic method of designer receptors exclusively activated by designer drugs (DREADD) system was adopted to mimic stress-related sleep disturbance. We transfected PVH CRH neurons with rAAV-hSyn-DIO-hM3Dq-mCherry and rAAV-Crh-CRE. Prolonged CRH neuron activation was induced by daily intraperitoneal injection of clozapine N-oxide (CNO, 3mg/kg) at 9 am. Bulk RNA-sequencing and bioinformatics analysis were conducted for mechanistic exploration.Results:2-week repeated chemogenetic activation of PVH CRH neurons induced a 5-fold corticosterone release, consistent with increased daily 3-hour wakefulness and corresponding decreases in both rapid eye movement (REM) as well as non-REM sleep. Over 30% of chronic CRH activation mice displayed difficulties in maintaining balance and experienced premature mortality. Mice subjected to prolonged CRH activation showed impaired left ventricular ejection fraction (67.9% versus 48.2%, p=0.0011), and immune cell infiltration demonstrated by histological staining. Intriguingly, the number of circulating monocytes increased. Then, we performed bulk RNA-sequencing of heart and bone marrow from CRH-activated and control mice. Differential gene expression and gene set enrichment analysis (GSEA) indicated marked activation of interferon-beta-related pathways in both tissues. Cytosolic DNA-sensing pathway and related key effector genes (cGAS, Cxcl10, Ccl5) were found up-regulated in the heart, while the mitochondrial oxidative phosphorylation pathway was suppressed. We further adopted the CIBERSORT tool to estimate immune infiltration in heart tissues and characterized M1 macrophage as the main pro-inflammatory cell. In our stress-related sleep disturbance mouse model, macrophages in the heart and bone marrow shared similar properties inducing interferon-stimulated genes.Conclusion(s):Taken together, we report a failing heart in a mouse model of stress-related sleep disturbance. The neuro-immune axis involvement and molecular mechanisms merit in-depth explorations.

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Novembre 2024

Abstract 4142869: Heritable heart failure traits in mice undergoing early life stress

Circulation, Volume 150, Issue Suppl_1, Page A4142869-A4142869, November 12, 2024. Introduction:Adverse childhood experiences, also known as early life stress (ELS), are associated with increased risk of cardiovascular disease in later life, yet the underlying mechanisms remain elusive. Recent evidence indicates that parental life experiences can be transmitted to the offspring.Aim:To investigate the effects of ELS on cardiac structure and function in exposed parents and in their offspring, across 3 generations.Methods:We used ELS mouse model based on unpredictable separation of mouse pups (F1) from their mother (F0) each day for 3 hours from postnatal day 1 (PND1) to PND14 combined with dams exposure to an additional unpredictable stressor (forced swim in 18°C water for 5 minutes or 20-minute physical restraint in a tube) during separation. Control litters were raised normally. Echocardiography was performed at 6, 12 and 18 months in exposed animals (F0), their unexposed offspring (F1) and grand-offspring (F2). Both male and female mice were studied. Heart weight/tibia length was used to assess cardiac mass while Masson’s Trichrome was employed to detect fibrosis. Lung congestion was assessed as lung wet/dry weight ratio. Single-cell RNA sequencing (scRNAseq) was performed in MSUS and control hearts. A 6-week environmental enrichment (EE) program (cages containing running wheels, maze) was employed to test the possible rescue of ELS effects in adult males and their offspring.Results:F1 MSUS mice displayed increased LV mass, impaired diastolic function (assessed by conventional and tissue Doppler analysis) myocardial fibrosis and lung congestion. Time-dependent worsening of cardiac performance was observed from 6 to 18 months, both in males and females. ScRNAseq unveiled dysregulation of transcriptional programs underlying inflammation and lipotoxicity in the cardiomyocyte and endothelial cell clusters. MSUS offsprings did not show changes of cardiac function at 6 months, however diastolic dysfunction and lung congestion were observed at 12 and 18 months. A similar impairment of cardiac function was observed in the MSUS grandoffspring (F3). Of interest, 6-week exposure to an environmental enrichment protocol was able to improve LV mass, diastolic function and lung congestion in 12 months-old MSUS mice.Conclusions:ELS induces a transgenerational transmission of cardiac phenotypic alterations which can be rescued by EE. Our results shed light on the potential role of ELS on heart failure development and potential mitigation strategies.

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Novembre 2024

Abstract 4146347: Oxidative Stress Lipids Associate with Mood Disturbance Symptoms and Quality of Life in Acute Ischemic Stroke Patients

Circulation, Volume 150, Issue Suppl_1, Page A4146347-A4146347, November 12, 2024. Background:Acute ischemic stroke (AIS) is a leading cause of mortality and disability globally, disproportionately affecting Black and Latinx populations who experience increased morbidity and mortality compared to their white counterparts. At one month, roughly 50% of AIS survivors experience mood disturbances (e.g., anger, irritability, and aggression) and exhibit a lower health-related quality of life (HRQOL) compared to pre-AIS levels. Downstream biomarkers of mitochondrial dysfunction such as oxidative stress may be important pathophysiological mechanisms underlying mood disturbance symptoms, stroke severity, and long-term functional recovery.Purpose:To examine associations among early and late peripheral plasma lipid levels, mood disturbance symptoms (e.g., anger, irritability), and HRQOL outcome over 3 months (baseline/study day 5, and months 1, 3) in persons following AIS.Methods:The pilot study is a non-probability, convenience sample of adult subjects ( > 18 years of age) with a diagnosis of AIS. Lipidomics analysis was performed using liquid chromatography-mass spectrometry (LC-MS) of untargeted lipids. The Agilent 6545 LC/Q-TOF platform was used to determine the absolute concentration of lipid species from peripheral plasma samples collected days 1, 3, 5 and months 1 and 3 post-AIS. General linear mixed models were used to test the predictive association of lipidomic biomarker mean value of peripheral plasma lipid levels and symptoms and outcomes over time (baseline and months 1 and 3).Results:We analyzed 82 subjects (age = 64 ± 12.1, 52% male, 78% Black, and 94% with hypertension). Elevated oxidative stress biomarkers (e.g., lipoxygenases, arachidonic acid, glycosylphosphatidylinositol) were associated with higher severity of anger and irritability symptoms, and a poorer HRQOL from baseline to 1- and 3-months post-AIS (p=0.04).Conclusion:An untargeted LC-MS lipidomics approach was used to identify lipids following AIS. Because oxidative stress plays a key regulatory role in complex downstream cellular function, these findings may be of great significance in understanding AIS pathophysiology that has the potential to inform personalized preventive strategies.

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Novembre 2024