Risultati per: Lo stress può essere causa di infarto ed ictus

Circulation, Volume 150, Issue Suppl_1, Page A4140181-A4140181, November 12, 2024. Systemic hyperglycemia causes tissue damage and triggers cardiovascular disease (CVD). Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) are a novel class of glucose-lowering agents that have shown unexpected benefits in clinical trials for the treatment of CVDs. We aim to investigate the underlying mechanisms of how SGLT-2 inhibitors alleviate CVDs associated with elevated glucose stress. iPSC-derived cardiomyocytes (iPSC-CM) were incubated with high glucose concentrations for 72 hours. Mitochondrial function in these cardiomyocytes was assessed by flow cytometry with JC-1 staining and ATP luminescence assay. Intracellular reactive oxygen species (ROS) and intramitochondrial calcium stress were measured using CellROX, MitoSOX, and Rhod-2 AM staining. Patch clamp was employed to determine ion current changes in the cardiomyocytes. Mitochondrial oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were determined using the Seahorse XFe96 analyzer. In addition, qPCR, Western blot, and DM mouse heart histological analysis were performed to assess the regulation of associated molecules. The results indicated that exposure to a high glucose environment caused cardiomyocyte injury and impaired mitochondrial biosynthesis. Empagliflozin exhibited a beneficial effect on mitochondrial function by reducing ROS production and calcium deposition. It also mitigated the reduction in respiratory OCR of cardiomyocytes induced by high glucose incubation. Furthermore, molecular analysis revealed that Empagliflozin attenuated the dysregulation of mitochondrial calcium channels and biosynthesis by reducing associated gene expression, includingBcl2,Mfn1,Mx2,Oas1,Ant3,Mcu,Micu1,Vdac1,Ryr2, andCypd-ppid. Histological analysis of DM mouse hearts demonstrated that reduced MFN2 and ZBP1 were target molecules for hyperglycemia-induced reduction of calcium channel currents in cardiomyocytes and could be restored by Empagliflozin treatment. This study concludes that high glucose stress diminishes mitochondrial calcium channel regulators MFN2 and ZBP1 in cardiomyocyte, which reduces calcium channel currents and leads to sensitization of cardiomyocyte to arrhythmogenesis, resulting in VT/VF. It provides experimental evidence for the clinical efficacy of Empagliflozin in ameliorating CVDs and managing diabetes-related CVDs.

Circulation, Volume 150, Issue Suppl_1, Page A4141446-A4141446, November 12, 2024. Emerging evidence suggests that vascular stress from cardiovascular-related co-morbidities promotes microvascular dysfunction, a key component in the development of heart failure with preserved ejection fraction. The sodium glucose co-transporter 2 (SGLT2) inhibitor empagliflozin has been shown to reduce both morbidity and mortality associated with heart failure with preserved ejection fraction, however the full scope of influence of this therapy on human microvascular function remains unknown. We hypothesized that pre-treatment of isolated human microvessels with empagliflozin will prevent stress-induced endothelial dysfunction as evidenced by preserving both the magnitude of flow-induced dilation (FID) as well as the ability to dilate to nitric oxide. Human resistance arterioles (80-250µm) from healthy adults (defined as patients with ≤1 risk factor for cardiovascular disease) were dissected from discarded surgical adipose tissue and treated with empagliflozin (1µM), or vehicle control (ethanol) for 16-20 hours prior to the flow experiment. Vessels were cannulated for videomicroscopy and subjected to high intraluminal pressure (150mmHg, 30 min), an acute stress known to induce endothelial dysfunction. Vessels were pre-constricted with endothelin-1 prior to initiation of flow. A nonlinear logistic regression was used to determine differences between curves. Compared to vehicle control, vessels pre-treated with empagliflozin (1µM ) exhibited nitric oxide-dependent FID as dilation was impaired in the presence of the nitric oxide synthase inhibitor L-NAME (EC50 Control: 10.7 vs L-NAME 83.45, p=0.0107). This data suggests that empagliflozin, an SGLT2 inhibitor, promotes microvascular resilience to stress via preservation of nitric oxide-mediated FID. The ability to elicit stress resilience may explain in part some of the cardiovascular benefits associated with SGLT2 inhibitors and may offer unique opportunities for early intervention or prevention of microvascular dysfunction associated with comorbidities that contribute to heart failure with preserved ejection fraction.

Circulation, Volume 150, Issue Suppl_1, Page A4146301-A4146301, November 12, 2024. Background:Exercise stress testing uses metabolic equivalents of tasks (METs) to measure the energy cost of activities, aiding in the assessment of exercise capacity and cardiovascular health. Despite its significance, the correlation between calf muscle pump function (CPF) and exercise stress testing remains unexplored. We aimed to evaluate the relationship between CPF and peak METs as determined by cardiopulmonary treadmill exercise stress testing.Methods:The study included adults who underwent exercise cardiopulmonary stress testing and venous plethysmography at Mayo Clinic between April 2017 and March 2020. The protocols other than Bruce, Mayo, Modified Naughton, and Naughton protocols were excluded. The CPF ejection fraction (EF) was calculated per leg based on refill volumes post-exercise as a percentage of passive drain refill. The classification of CEAP (Clinical-Etiology-Anatomy-Pathophysiology) was utilized to better understand chronic venous insufficiency (CVI).Results:A total of 155 patients who underwent both exercise stress testing and venous plethysmography were included, with a mean age of 61.31 ± 14.03 years, and 84 (54.2%) were male. The peak measured METs for normal, unilaterally reduced, and bilaterally reduced CPF were 8.5 (2.5), 7.3 (2.1), and 7.1 (2.4), respectively (p=0.004, Figure 1). Multiple linear regression models were developed with METs as the outcome to determine if CPF was an independent predictor of METs on cardiopulmonary exercise stress testing. IIn model 1, the following independent variables were included: resting heart rate, peak heart rate, peak systolic blood pressure, recovery heart rate at minute 1, and worst EF (Table 1). In model 1, with only exercise parameters, lower EF was associated with lower METs (p=0.03). In a second analysis, variables identified as statistically significant with METs in the initial model were included, along with CEAP class (model 2) and CCI (model 3) (Table 2). In model 2, CEAP class 3 or higher was associated with decreased METs on the exercise stress test. This correlation implies that individuals with moderate to severe CVI may influence exercise capacity, demonstrating the interconnectedness of the cardiovascular system. Moreover, in model 3, the CCI, a predictor for mortality, was not significantly associated with METs.Conclusion:Our findings revealed that more severe CVI (CEAP class and reduced CPF) was associated with reduced exercise capacity after accounting for other factors.

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.

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

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.

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.

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.

Circulation, Volume 150, Issue Suppl_1, Page A4145955-A4145955, November 12, 2024. Introduction:Cardiovascular problems are the primary cause of morbidity and death in people with diabetes mellitus.The whole nature of diabetic cardiomyopathy(DCM) is yet unknown.In order to investigate the pathogenesis of DCM and find possible treatment targets,animal models have proven invaluable.It has been common practice to create experimental models of type 2 diabetes(T2DM) using streptozotocin (STZ).Finerenone(F) is a selective mineralocorticoid receptor antagonist and reduces cardiovascular and adverse renal outcomes in diabetes.Exenatide(E) has been approved by the FDA to improve glycemic control in T2DM.Aim:The aim of this study is to investigate the possible cardiorenal protective effects of potential heart failure and chronic kidney injury associated with T2DM and to assess the potential therapeutic roles of Finerenone and Exenatide.To understand the interactions on cardiorenal outcomes of heart failure and diabetes and to effectively manage these two conditions.Methodology:Wistarmale rats with streptozotocin-induced T2DM were used.Five different groups were established as 1)Control,2)STZ,3)STZ+F,4)STZ+E,5)STZ+F+E groups.During the 21-day experiment, blood glucose concentrations were measured in all animal experimental groups.The kidney, heart tissues, and blood serum were collected. Serum urea and creatinine were exanimated.Total antioxidant status(TAS) and total oxidant status(TOS) were examined from blood serum,kidney,heart tissues by spectrophotometric assays. Kidney, heart tissues and blood IL-6, IL-1β, TNF-α gene expressions were examined by qPCR. Cardiac troponin T(cTnT) and troponin I(cTnI) gene expressions were examined by qPCR.p-STAT3 and p-NRF2 protein expressions in heart tissue were assessed by western blotting.Results:Serum urea and creatinine were significantly lower in STZ+E+F group than control group. TAS were significantly higher in STZ+E+F group than control group in serum,heart and kidney tissues.TOS, IL-1β, IL-6, and TNF-α gene expressions were lower in STZ+E+F groups than control group significantly in serum, heart and kidney tissues.cTnT and cTnI gene expressions and p-STAT3 and p-NRF2 protein expressions were lower in STZ+E+F groups than control group significantly in heart tissues.Conclusion:This study demonstrates the potential beneficial effects of Finerenone and Exenatide on cardiorenal complications in T2DM. Evaluation of these drugs in treatment strategies and further clinical trials are recommended.

Circulation, Volume 150, Issue Suppl_1, Page A4141710-A4141710, November 12, 2024. Background:Stress perfusion CMR has excellent diagnostic and prognostic values in assessing chest pain syndromes. AI-guided methods may overcome complex scanning and increase clinical adaptation of stress CMR.Aim:To assess the benefits of AI-guided stress perfusion CMR.Methods:Consecutive patients with stable chest pain underwent stress CMR using either a standard scanning method (SOC) or an AI-assist (AIA) machine learning protocol to automate scan planning, plane prescription, sequence tuning, and image reconstruction. Scan duration, the ratio of scan preparation time over the entire scan duration, and scan quality using a 5-point scale were compared between AIA and SOC. Cox regression models were constructed to associate evidence of ischemia on stress CMR, by either scanning method, with composite endpoints including cardiovascular death, non-fatal MI, unstable angina hospitalization, and late CABG. A second composite endpoint included the performance of additional cardiac imaging tests (stress imaging and CCTA) and invasive coronary procedures after CMR.Results:Among 594 patients (62.8 ± 14 years), 29% underwent stress CMR with AIA. 26% had stress-perfusion ischemia, and 39% had LGE present. AIA stress CMR had lower scan duration (median 44.0 [IQR 40-47] vs. 52.5 min [IQR 46-60]; p

Circulation, Volume 150, Issue Suppl_1, Page A4131424-A4131424, November 12, 2024. Introduction:Anomalous aortic origin of a coronary artery (AAOCA) can result in sudden cardiac death in the young and risk stratification is challenging. Though dobutamine stress cardiac MRI (DS-CMR) is feasible in pediatric patients, exercise stress CMR (ES-CMR) has lower rates of adverse events, higher diagnostic accuracy, and the ability to better reflect the physiologic changes occurring with exercise. No studies have evaluated ES-CMR in the pediatric population. We aim to describe our institution’s experience with ES-CMR using supine bicycle ergometry in patients with AAOCA.Methods:We retrospectively reviewed the medical records of AAOCA patients who underwent ES-CMR at our institution between 2011 and 2024 for demographic, clinical presentation, cardiopulmonary exercise test (CPET) and ES-CMR data. The exercise-based portion of the CMR consisted of supine cycle ergometry utilizing a ramp protocol, immediately after which perfusion imaging was performed. We used descriptive statistics for data analysis.Results:Of 38 patients who underwent ES-CMR, the median age was 16 years (range 13-24) and 68% were male. Diagnoses included anomalous right coronary artery (N=28), anomalous left coronary artery (N=8), and single coronary artery (N=1 single right, N=1 single left). Median maximal heart rate (HR) during ES-CMR was 160 bpm (range 130-190, median 80% predicted) with a median maximal HR during patients’ most recent CPET of 187 bpm (range 160-203, median 97% predicted). No patients had perfusion defects at rest or with exercise stress, or evidence of myocardial scarring. There were no adverse events.Discussion:We demonstrate for the first time the use of ES-CMR in a cohort of pediatric and young adult patients with AAOCA. ES-CMR can provide a unique modality to assess for ischemia at rest and stress as a means of risk stratification and simulate physiologic changes occurring with exercise stress in a single study. Although maximum heart rates during supine cycle ergometry are lower than those reached during CPET, they are similar to those reached during DS-CMR. ES-CMR can be a helpful and safe diagnostic tool in patients with AAOCA.

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.

Circulation, Volume 150, Issue Suppl_1, Page A4141350-A4141350, November 12, 2024. Background:Atrial fibrosis is crucial in developing atrial fibrillation (AF). Elevated atrial pressure may significantly mediate atrial fibrosis, yet its underlying mechanisms remain unclear.Methods:Patients with AF who underwent radiofrequency ablation were recruited. Clinical data, including high-density mapping and imaging information, was analyzed. Multivariate regression analysis was performed to identify risk factors for low-voltage areas in the atrium. The CS-CREM mouse model, an autonomic AF model, was previously developed by our research group. Millar pressure catheters were used to measure left ventricular, right ventricular, and right atrial pressures in CS-CREM mice. Single-nucleus sequencing was employed to map the single-cell transcriptomes of atrial samples in CS-CREM and wild-type mice at different disease stages. Human primary atrial endocardial endothelial cells (ACCE) and HUVEC cell lines were subjected to mechanical stretch using the Flexcell tension system, followed by in vitro validation experiments. Mg101, a calpain inhibitor, was administered to CS-CREM mice for in vivo validation experiments.Results:Elevated atrial pressure in AF patients was identified as a significant risk factor for atrial fibrosis. Atrial pressure-related indices were linearly correlated with atrial fibrosis. Compared to wild-type mice, CS-CREM heterozygous mice exhibited significantly higher atrial pressure and aggravated atrial fibrosis. Single-nucleus sequencing revealed that atrial endocardial endothelial cells in CS-CREM mice underwent endothelial-mesenchymal transition (EnMT) into fibroblasts, with mechanical stress protein Flna being a critical regulatory protein. In vitro experiments demonstrated mechanical stretch-induced EnMT in ACCE and HUVEC cell lines. Mechanical stretch-activated mechanosensitive receptors on ACCE cell membranes led to increased intracellular calcium levels and calpain activation, which cleaved Flna into Flna 90. Flna 90 facilitated the nuclear translocation of transcription factor Smad3/7 and TGF-β, promoting the expressions of EnMT genes. This EnMT process was reversible with Mg101. In vivo experiments showed that Mg101 reduced the incidence of AF and mitigated atrial fibrosis in CS-CREM mice.Conclusion:Mechanical stress induces cleaved Flna 90 from Flna in atrial endocardial endothelial cells, thus assisting transcription factors Smad3/7 and TGF-β in nuclear translocation, regulating EnMT and mediating atrial fibrosis.

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.

Circulation, Volume 150, Issue Suppl_1, Page A4147667-A4147667, November 12, 2024. The co-chaperone BAG3 is critical for protein quality control at the cardiac sarcomere. BAG3 binds to Hsp70 and coordinates the assembly of the CASA (chaperone-assisted selective autophagy) complex, thus supporting proteostasis and cardiomyocyte contractility. BAG3 mutations and/or decreased BAG3 levels are associated with cardiomyopathies, whereas BAG3 overexpression rescues ventricular function after myocardial infarction in mice. Despite BAG3’s promise as a therapeutic target, the mechanisms underlying BAG3 regulation are largely unresolved. Here, we investigate the mechanisms of BAG3 downregulation after stress. We found that BAG3 protein is reduced in human dilated cardiomyopathy hearts compared to non-failing hearts, yet there is an increase inbag3mRNA transcript, suggesting BAG3’s downregulation in heart disease may be controlled post-transcriptionally. To identify these post-transcriptional pathways, we subjected neonatal rat ventricular myocytes (NRVMs) to prolonged hypoxia-reoxygenation (H/R) stress, which recapitulated the decrease in BAG3 levels observed in human heart disease. Notably, disrupting Hsp70 binding to BAG3 in NRVMs via the drug JG-98 decreases BAG3’s half-life by ~90%, suggesting that Hsp70 protects BAG3 from degradation. Loss of Hsp70-mediated protection could contribute to declining BAG3 levels, so we quantified Hsp70 abundance after H/R stress in NRVMs, finding no significant change. We also found that overexpressing inducible Hsp70 did not rescue BAG3 levels. To examine BAG3 regulationin vivo,we subjected wildtype mice to ischemia-reperfusion injury. After 24 hours, male mice had no change in Hsp70 abundance in the left ventricle, whereas Hsp70 was significantly upregulated in female mice. Despite this difference in Hsp70, BAG3 levels were decreased by ~20% in both sexes. Thus, ourin vivoandin vitrodata both suggest that BAG3 downregulation is not caused by loss of Hsp70 binding/protection. Interestingly, the decline in full-length BAG3 (85 kDa) was accompanied by an increase in a BAG3 cleavage product at 74 kDa. We analyzed this product via mass spectrometry, discovering that it lacks a third of the WW domain, which is involved in autophagy. In future experiments, BAG3 cleavage will be explored as a potential mechanism of BAG3 loss. Such mechanisms will provide insight into how to maintain BAG3 levels, and thus cardiac function, during stress.

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