Pressure Overload Research Articles

Effects of tirzepatide on circulatory overload and end-organ damage in heart failure with preserved ejection fraction and obesity: a secondary analysis of the SUMMIT trial

AbstractPatients with obesity-related heart failure with preserved ejection fraction (HFpEF) display circulatory volume expansion and pressure overload contributing to cardiovascular–kidney end-organ damage. In the SUMMIT trial, patients with HFpEF and obesity were randomized to the long-acting glucose-dependent insulinotropic polypeptide receptor and glucagon-like peptide-1 receptor agonist tirzepatide (n = 364, 200 women) or placebo (n = 367, 193 women). As reported separately, tirzepatide decreased cardiovascular death or worsening heart failure. Here, in this mechanistic secondary analysis of the SUMMIT trial, tirzepatide treatment at 52 weeks, as compared with placebo, reduced systolic blood pressure (estimated treatment difference (ETD) −5 mmHg, 95% confidence interval (CI) −7 to −3; P < 0.001), decreased estimated blood volume (ETD −0.58 l, 95% CI −0.63 to −0.52; P < 0.001) and reduced C-reactive protein levels (ETD −37.2%, 95% CI −45.7 to −27.3; P < 0.001). These changes were coupled with an increase in estimated glomerular filtration rate (ETD 2.90 ml min−1 1.73 m−2 yr−1, 95% CI 0.94 to 4.86; P = 0.004), a decrease in urine albumin–creatinine ratio (ETD 24 weeks, −25.0%, 95% CI −36 to −13%; P < 0.001; 52 weeks, −15%, 95% CI −28 to 0.1; P = 0.051), a reduction in N-terminal prohormone B-type natriuretic peptide levels (ETD 52 weeks −10.5%, 95% CI −20.7 to 1.0%; P = 0.07) and a reduction in troponin T levels (ETD 52 weeks −10.4%, 95% CI −16.7 to −3.6; P = 0.003). In post hoc exploratory analyses, decreased estimated blood volume with tirzepatide treatment was significantly correlated with decreased blood pressure, reduced microalbuminuria, improved Kansas City Cardiomyopathy Questionnaire Clinical Summary Score and increased 6-min walk distance. Moreover, decreased C-reactive protein levels were correlated with reduced troponin T levels and improved 6-min walk distance. In conclusion, tirzepatide reduced circulatory volume–pressure overload and systemic inflammation and mitigated cardiovascular–kidney end-organ injury in patients with HFpEF and obesity, providing new insights into the mechanisms of benefit from tirzepatide. ClinicalTrials.gov registration: NCT04847557.

Magnetic resonance imaging of pulmonary hypertension.

Pulmonary hypertension is a rare but serious disease in children with potentially poor prognosis in the long term. Direct measurement of increased pressure in the pulmonary circulation requires right-heart catheterisation. Echocardiography is the imaging modality commonly used for suggesting the presence of pulmonary hypertension and estimating its severity. Recognition of structural and haemodynamic signs of increased pulmonary arterial pressure and pressure overload of the right ventricle at magnetic resonance (MR) imaging may contribute to the diagnosis of pulmonary hypertension and management of these patients. In this article, the structural, functional, and haemodynamic cardiovascular MR findings of paediatric pulmonary hypertension are reviewed. Typical diagnostic MR scenarios in children with suspected pulmonary hypertension or in children with disease associated with pulmonary hypertension are presented and discussed.

Cell-based therapies reverse the heart failure-altered right ventricular proteome towards a pre-disease state.

Congenital heart defects can lead to right ventricular (RV) pressure-overload and heart failure. Cell-based therapies, including mesenchymal stromal cells (MSCs) and c-kit positive cells (CPCs) have been studied clinically as options to restore heart function in disease states. Many studies have indicated these cells act through paracrine mechanisms to prevent apoptosis, promote cellular function, and regulate gene/protein expression. We aimed to determine the proteomic response of diseased hearts to cell therapy. We utilized a juvenile rat model of RV pressure overload created by banding the pulmonary artery (PAB). Two weeks post-banding, bone marrow-derived mesenchymal stromal cells (MSCs) and 3 populations of CPCs (nCPCs, cCPCs, ES-CPCs) were delivered to the RV free wall. RV function and cellular retention were measured for four weeks post-injection, at which point hearts were extracted and the RV was excised for liquid chromatography and tandem mass spectrometry. Resulting RV proteomes were compared and analyzed using systems biology and bioinformatics. Proteomic profiling identified 1156 total proteins from the RV, of which 5.97% were significantly changed after PAB. This disease-altered proteome was responsive to cellular therapy, with 72% of the PAB-altered proteome being fully or partially reversed by MSC therapy. This was followed by nCPCs (54%), ES-CPCs (52%), and cCPCs (39%). Systems biology and bioinformatics analysis showed MSC, nCPC, or ES-CPC cell therapy is associated with a decrease in predicted adverse cardiac effects. We also observed an effect of cell therapy on the non-altered RV proteome, however, this was associated with minor predicted pathological endpoints. Our data indicate MSCs, ES-CPCs, and nCPCs significantly reverse the PAB-altered proteome towards a pre-disease state in our animal model. These results indicate cell-based therapies show promise in improving RV function after pressure overload through partial restoration of the disease-altered cardiac proteome.

Abstract 4134695: The Effect and Mechanism of Histone Lactylation In Pathological Cardiac Hypertrophy Induced by Pressure Overload

Introduction: Cardiac hypertrophy is characterized by significant metabolic changes, notably an increase in glycolysis. Histone lactylation, a post-translational modification influenced by the glycolytic state of cells, plays a crucial role in regulating gene transcription. However, the relationship between histone lactylation and cardiac hypertrophy remains unclear. Research Questions: This study aims to elucidate the effects and underlying mechanisms of histone lactylation in the progression of cardiac hypertrophy induced by pressure overload. Methods and Results: We observed an increase in histone lactylation levels in hypertrophic hearts from both humans and mice. To investigate further, male mice underwent transverse aortic constriction (TAC) to induce cardiac hypertrophy, followed by either an intraperitoneal injection of Oxamate (an LDHA inhibitor) to reduce histone lactylation or sodium lactate to increase it. Reducing histone lactylation protected the hearts from TAC-induced hypertrophy and fibrosis, preserving cardiac function, while increased histone lactylation exacerbated cardiac hypertrophy and fibrosis, impairing cardiac function. Cardiomyocyte-specific deletion of LDHA also led to a reduction in cardiac hypertrophy. In vitro experiments showed that inhibiting histone lactylation reduced the expression of hypertrophic markers and the hypertrophic growth of cardiomyocytes stimulated by phenylephrine. Using co-immunoprecipitation, we confirmed that P300 and GCN5 are the transferases mediating histone lactylation in cardiomyocytes. Mechanistic studies using the CUT&Tag technique revealed lactate-dependent histone modification was enriched at the promoter of TGFB2, activating its transcription. Inhibiting cardiac-specific TGFB2 expression through adeno-associated viral delivery of shRNA reduced TAC-induced cardiac hypertrophy. Furthermore, TGFB2 overexpression induced a hypertrophic phenotype in cardiomyocytes and activated the PI3K/AKT/mTOR pathways. This hypertrophic phenotype, induced by TGFB2 overexpression, was suppressed by inhibitors of PI3K or AKT. Conclusion: Our findings reveal a critical role for histone lactylation in the development of pathological cardiac hypertrophy by regulating TGFB2 expression and the PI3K/AKT/mTOR pathway.

Abstract 4115947: Empagliflozin Inhibits the Mobilization of CCR2+ Monocyte-Derived Macrophages by Reducing CCL2 Expression in Fibroblasts and Slows the Progression of Heart Failure After Pressure Overload.

Background: The positive effects of sodium glucose co-transporter-2 (SGLT2) inhibitors on reducing cardiovascular mortality and hospitalizations due to heart failure have been well established. Although numerous theories propose explanations for the cardioprotective actions of SGLT2 inhibitors, these hypotheses primarily rely on initial findings and require further validation. Studies have shown that immune cells, particularly macrophages marked by C-C chemokine receptor type 2 (CCR2), contribute to the progression of heart failure by infiltrating the myocardium and inducing detrimental structural changes following myocardial infarction or pressure overload. Purpose: This study aims to investigate whether SGLT2 inhibitors can mitigate heart damage by inhibiting the migration of CCR2+ monocyte-derived macrophages. Methods: In this experiment, male B6 mice were subjected to transverse aortic constriction (TAC) to induce heart failure. Two weeks post-TAC, with heart function confirmed as equal across all groups by echocardiography, one group began receiving daily oral doses of empagliflozin, while another served as the control. At four weeks post-TAC, cardiac function was reassessed. The animals were then euthanized, and their hearts were analyzed using flow cytometry, staining, and qPCR to evaluate heart failure and the involvement of immune cells. Additionally, isolated cardiac fibroblasts were subjected to cyclic stretching to mimic post-TAC mechanical stress. Results: Treatment with empagliflozin resulted in improved cardiac function and reduced congestion in the heart and lungs, indicating alleviation of heart failure. The treatment notably decreased myocardial fibrosis, evident from Picrosirius-red staining and reduced expression of fibrosis-related mRNA. Importantly, empagliflozin specifically reduced the number of CCR2-positive macrophages in the heart, without affecting other types of immune cells. In cardiac fibroblasts that underwent cyclic stretching, empagliflozin pre-treatment diminished the expression of C-C motif chemokine ligand 2 (CCL2), the ligand for CCR2. Conclusion: Empagliflozin’s ability to suppress CCL2 expression in fibroblasts and curtail the recruitment of CCR2+ macrophages may represent a potential strategy to decelerate heart failure progression. These findings advance our understanding of the cardioprotective mechanisms of SGLT2 inhibitors and propose novel therapeutic avenues for heart failure management.

Abstract 4137717: Atrial Fibrillation in Valvular Heart Disease: Assessing the Impact of Genetics in the UK Biobank

Background: Atrial fibrillation (AF) in valvular heart disease (VHD) is typically linked to pressure or volume overload resulting in atrial remodeling. However, the independent contribution of genetics to AF in VHD beyond abnormal hemodynamics and other risk factors remains unclear. Objective: To study the role of a previously developed Polygenic Risk Score (PRS) for AF in predicting AF across different VHDs in the UK Biobank cohort. Methods: We analyzed UK Biobank data between 2000 and 2022. ICD codes were used to define incident AF and VHD status, including mitral valve (MV) disease [prolapse (MVP), regurgitation (MR) and stenosis (MS)] and aortic (AV) disease [stenosis (AS) and regurgitation (AR)]. Prior AF was excluded. Participants were divided into quintiles based on the PRS: the top quintile was defined as high genetic AF risk, second through fourth as intermediate genetic risk, and bottom quintile as low genetic risk. Results: Among 452841 participants with available PRS, 2238 had at least one VHD (385 MVP, 1058 MR, 81 MS, 421 AR, and 509 AS). AF incidence was 9.9%, 13.6%, and 19% in the low, intermediate and high genetic risk groups respectively, compared to 1.4%, 2.8%, and 5.7% in the general population (all p<0.05) - Figure 1A . Cox regression models adjusted for cardiovascular risk factors showed different genetic effects on AF across VHD types. Censoring patients at death, including valve intervention as a time-dependent variable, and excluding AF within 30 days post-intervention, PRS independently predicted AF in MV disease (hazard ratio [HR] 1.7, p=0.03 for the intermediate risk/mid PRS; HR 2.3, p=0.002 for the high risk PRS), particularly in those with MVP (HR 3.1, p=0.03 for the high PRS). However, in those with AV disease, PRS was not significantly associated with AF (p=0.93 and p=0.07) - Figure 1B. Conclusion: In patients with VHD, AF PRS is significantly associated with an increased risk of developing AF. However, the genetic impact varies across different VHD. In AV disease, there is a minimal genetic contribution, and the elevated AF risk may be predominantly due to pressure or volume overload. In contrast, in MV disease, particularly in MVP, there is a substantial genetic influence on AF risk.

Abstract 4136605: Effect Of A Bone Morphogenetic Protein Receptor Type 2 Mutation On The Cardiomyocyte Response To Pressure Overload

Introduction: A mutation in the Bone Morphogenetic Protein Receptor Type 2 ( BMPR2 ) gene is in 70% of hereditary pulmonary arterial hypertension (hPAH) patients the causative mutation of the disease. Previous work demonstrated that right ventricular function is more impaired in hPAH patients with a BMPR2 mutation. However, the underlying mechanism remains elusive. Moreover, natriuretic peptides, such as N-terminal Brain Natriuretic Peptides (NTproBNP) and Mid Regional proAtrial Natriuretic Peptides (MRproANP), are secreted from cardiomyocytes upon stretch as adaptation to increased pressure overload. We hypothesize that the BMPR2 mutation impairs the response to increased pressure overload. For this purpose, we make use of ventricular induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of hPAH patients carrying a BMPR2 mutation and their isogenic controls in which the mutation was corrected. Aim: To study the effect of a BMPR2 mutation on the response to pressure overload in vitro . Methods: iPSCs from 2 hPAH patients and its isogenic controls were used. iPSCs were differentiated into ventricular iPSC-CMs and stretched 10% equiaxially for 24h at 1Hz on the Flexcell FX-6000 system. Natriuretic peptides gene expressions were quantified via RT-PCR. NTproBNP and MRproANP release were measured on cell supernatants throughout specific immunoassays. Normality of the data was checked, and statistics were performed accordingly. Results: No differences were observed on natriuretic peptides gene expression on static and stretched iPSC-CMs. There is a clear correlation between NTproBNP and MRproANP release (R 2 =0.83, p<0.0001, Figure 1A). Interestingly, hPAH iPSC-CMs showed higher baseline values for NTproBNP release compared to isogenic iPSC-CMs (p<0.01, Figure 1B). Furthermore, stretching resulted in increased NTproBNP and MRproANP secretion in both hPAH and isogenic iPSC-CMs (Figure 1B-C). Conclusions: Secretion of NTproBNP and MRproANP was closely correlated in iPSC-CMs. iPSC-CMs of hPAH patients with a BMPR2 mutation showed higher baseline values of NTproBNP. Increased secretion of NTproBNP and MRproANP upon mechanical stimulation was similar between hPAH and isogenic iPSC-CMs. Experiments in atrial iPSC-CMs are currently ongoing to test potential differences in natriuretic peptide secretion between ventricular and atrial cardiomyocytes as the right atrium is also under stretch in PAH.

Abstract 4136316: BMP10 as novel marker for right atrial dilatation and pressure in precapillary pulmonary hypertension

Introduction: Precapillary pulmonary hypertension (precPH) leads to increased right atrial (RA) stretch and pressure. The right atrium is the major source of bone morphogenetic protein 10 (BMP10) in adults. Aim: This study aims to investigate BMP10 in relation to RA dilatation and pressure overload. Methods: We studied BMP10 mRNA in fresh RA tissue of N=5 Chronic Thromboembolic Pulmonary Hypertension (CTEPH) patients and N=9 controls and protein expression in paraffin-embedded RA tissue of N=4 Pulmonary Arterial Hypertension (PAH) patients and N=6 controls. We prospectively included 48 precPH patients (N=22 idiopathic PAH, N=14 hereditary PAH and N=12 CTEPH, and N=16 controls. To study BMP10-induced transcriptional activity, we assayed serum samples in human microvascular endothelial cells (HMEC) with a BMP-responsive transcriptional luciferase assay. BMP10 activity was calculated by subtracting BMP activity after incubation with antibodies for Alk1Fc and bone morphogenetic protein 9 (BMP9). We assessed correlations between BMP10 activity and RA dilatation (RA max volume>79 ml/m 2 for male or >69 ml/m 2 for female) and right ventricular (RV) dilatation (RV end-diastolic volume>108 ml/m 2 for male and >96 ml/m 2 for female). In a cohort of CTEPH patients that underwent pulmonary endarterectomy (PEA) we assessed the effect of pressure unloading on BMP10 activity. Normality of data was checked and statistical differences between groups were tested using an independent sample t-test or Wilcoxon rank-sum test. Results: BMP10 mRNA, protein and downstream activity were higher in the precPH RA tissue (Figure 1A-F). High systemic BMP10 activity was associated with RA dilatation and high RA pressure, but not RV dilatation in precPH (Figure 2A-C). Finally, pressure unloading after PEA in CTEPH patients results in a reduction in BMP10 activity (figure 2D). Conclusions: Local RA BMP10 expression and activity is increased in precPH. Increased systemic BMP10 activity was related to RA dilatation and pressure. Pressure unloading of the right heart leads to a reduction of systemic BMP10 activity. Future studies are needed to determine whether increased BMP10 release is an adaptative mechanism or can be used as therapeutic target.

Abstract 4134975: ROS-Traf6-Yap Promotes the Development of Cardiac Hypertrophy

Introduction: Heart failure (HF) is caused by structural and functional abnormalities of the heart and is associated with high morbidity and mortality. Pathological myocardial hypertrophy accounts for a significant portion heart failure. The Yap protein was found to be responsive to mechanotransduction signals and can limit organ size by inducing cell cycle arrest during development. In the heart, pathological activation of Yap has been shown to drive cardiac hypertrophy, but regenerative activation of Yap can promote myocardial cell-cycle re-entry. However, how Yap is pathologically activated in the beating cardiomyocyte remains elusive. Hypothesis: ROS-Traf6 promotes the development of cardiac hypertrophy by activating Yap in a non-canonical fashion. Methods: Traf6 protein levels in heart failure patients biopsies as well as in various murine failing hearts were examined by immunofluorescence. Molecular interrogation of ROS-Traf6-Yap signaling axis was performed in primary neonatal rat cardiomyocytes (NRCM) and human induced pluripotent stem cell derived cardiomyocytes. Yap protein stability and activation by Traf6 was examined by immunoprecipitation, CHX induction, and point mutation. Myocardial specific Traf6 knockout and Yap mutant animals were used to evaluate Traf6-Yap signaling in vivo . Results: We found that Traf6 expression was significantly elevated in multiple heart failure models. Using the transverse aortic constriction (TAC)-induced cardiac hypertrophy model, pressure overload increased ROS levels which activated Traf6. Traf6 overexpression induced myocardial hypertrophy while knockdown blocked myocardial hypertrophy in Ang II treated NRCMs. Mechanistically, Traf6 binds to and ubiquitinates Yap-K234 – this promotes Yap protein stability and nuclear translocation evidenced by increase in phosphorylated Yap. Myocardial Traf6 deficiency prevents TAC-induced cardiac hypertrophy. Moreover, overexpression of Yap-K237 mutant did not restore TAC-induced cardiac hypertrophy in myocardial Yap deficient mice. Conclusions: Our results demonstrate that non-canonical Yap activation is responsible for pressure overload induced cardiac hypertrophy. Targeting of the newly identified ROS-Traf6-Yap signaling axis may provide a new approach to prevent pathogenic cardiac hypertrophy.

Abstract 4137935: Adipogenesis in Bone Marrow Niche under Cardiac Stress Worsens Cardiac Function

Background: We have recently reported that repetitive cardiac decompensation with multimorbidity often experienced by patients with heart failure (HF) is attributed to epigenetic modifications of hematopoietic stem cells (HSCs) in the bone marrow (BM). HF reprogrammed HSCs differentiation and altered tissue macrophage homeostasis. These findings demonstrate that the BM can carry an innate immune memory of cardiac stress that may exacerbate HF and predispose other organs to pathology. Aims: Because the stemness of HSCs is mainly regulated by mesenchymal stromal cells (MSCs) in the BM niche, we investigated phenotypic alterations of MSCs under cardiac stress. Methods&Results: Transcriptome analysis of MSCs showed preferential differentiation toward adipocytes in murine pressure overload models. In vitro assays and histological BM sections also support this finding. Furthermore, single-cell RNA sequencing of MSCs demonstrated that the percentage of adipocyte-primed MSCs increased in proportion to the severity of cardiac dysfunction, and also correlated with the frequency of myeloid-lineage progenitor cells. To investigate the influence of adipo-lineage MSCs on HSCs, we conducted BM transplantation supplemented with MSCs from control or HF mice. Recipient mice transplanted with HF-MSCs showed significant increases in myeloid-biased multipotent progenitors in BM and myeloid cells in peripheral blood. Additionally, the number of proinflammatory cardiac macrophages was significantly increased in the HF-MSCs group, promoting cardiac fibrosis and dysfunction. Conclusions: Our results demonstrated that the BM niche could perceive cardiac stress in the form of adipocytic skewing of MSCs in the setting of HF, which changed the differentiation behavior in HSCs and ultimately led to further deterioration of cardiac function through the impaired differentiation of circulating monocytes into cardiac macrophages. Therefore, suppressing the adipocytic differentiation of MSCs could have a novel therapeutic potential to avoid repeated HF events.

Abstract 4136136: Left Ventricular Global Longitudinal Strain: An Imaging Marker Associated with Improved Survival in Paradoxical Low-Flow, Low-Gradient Severe Aortic Stenosis

Background: The optimal clinical management and timing of intervention are less well defined in paradoxical low-flow, low-gradient severe aortic stenosis (PLFLG AS). Left ventricular global longitudinal strain (LV-GLS) has been shown to predict outcomes in high flow severe AS, but there is lack of data in patients with PLFLG AS. Given the exaggerated LV hypertrophy and remodeling pattern in PLFLG AS, LV-GLS may be a mechanistic imaging marker for worse outcomes. Hypothesis: In patients with PLFLG AS, LV-GLS is associated with adverse clinical outcomes by detecting subclinical myocardial fibrosis resulting from myocardial remodeling due to LV pressure overload. Methods: We examined patients with PLFLG AS defined as AVA <1cm 2 , mean gradient <40mmHg and preserved left ventricular ejection fraction (LVEF) ≥50%, with low-flow state defined as transvalvular flow rate (Q) ≤210 ml/sec. Exclusion criteria included moderate or greater mitral or aortic regurgitation and presence of atrial fibrillation at the time of echocardiogram. LV strain analysis was performed using 2D-strain imaging software (TomTec, Chicago, IL). Clinical outcome data were obtained via the electronic health record. The primary outcome was defined as all-cause mortality. Patients were stratified by LV-GLS above and below the median value. Results: A total of 198 patients were included in the analysis, with a median LV-GLS of -12.3% [IQR: (-9.8,-16.3)]. Over a median follow-up time of 1.2 years, 130 deaths (65.6%) were identified. Patients with less negative LV-GLS (n=101) had worse survival than those with more negative LV-GLS (n=97; 22 vs 38%; p=0.02) (Fig 1). After multivariable adjustment for potential confounders (stroke volume index, aortic valve mean gradient, relative wall thickness, age, sex, heart failure, hypertension, coronary artery disease, and diabetes), less negative LV-GLS was independently associated with adverse outcomes (HR 1.56; 95% CI (1.03-2.38); p=0.04). Conclusions: In patients with PLFLG AS as defined by a transvalvular flow rate (Q) ≤210 ml/sec, reduced LV-GLS is associated with increased all-cause mortality. LV-GLS may serve as an imaging marker to help guide clinical decision making in PLFLG AS.

Abstract 4135531: The Ubiquitin-Specific Protease 30 Inhibitor, MTX652, Attenuates Cardiac Dysfunction And Remodelling In a Murine Model Of Transverse Aortic Constriction

Introduction: Mitochondrial abnormalities are a characteristic of heart failure leading to energy deprivation and disease worsening. The mitochondrial deubiquitinating enzyme USP30, removes ubiquitin and represses PINK1/PARKIN-mediated mitophagy leading to accumulation of dysfunctional mitochondria. In this study we investigated the role of MTX652, a clinical stage USP30 inhibitor, in a mouse model of cardiac hypertrophy using transverse aortic constriction (TAC). Hypothesis: Inhibition of USP30 will promote mitophagy resulting in clearance of dysfunctional mitochondria and improved cellular health leading to cardioprotective effects. Aims: To determine if MTX652 can protect from TAC induced cardiac hypertrophy and remodelling. Methods: Male C57BL/6 mice, 8 weeks old, were subjected to sham surgeries or TAC using a 26G needle to induce cardiac pressure overload. MTX652 (1.5 or 5 mg/kg, n =12-13) or vehicle ( n =11) was administered orally, twice daily, starting 2 days post-surgery. Captopril (30 mg/kg/d, n =13) was also included as a positive control. After 4 weeks, echocardiography assessed left ventricle (LV) function and morphology. Cell based assays assessed MTX652 target engagement and TOM20 ubiquitination in vitro. Results: LV hypertrophy and wall thickening was observed in TAC animals. Treatment with MTX652 decreased systolic LV volume (1.5 mg/kg p<0.05 and 5 mg/kg p<0.01) and diameter (1.5 mg/kg p<0.01 and 5 mg/kg p<0.05,) demonstrating comparable effects to Captopril. A reduction in anterior wall thickness in diastole was also observed with MTX652 (5 mg/kg, p<0.01). Cardiac dysfunction was also evident in TAC animals with MTX652 showing improvements in both ejection fraction (1.5 mg/kg and 5 mg/kg, p<0.0001) and fractional shortening (1.5 mg/kg and 5 mg/kg, p<0.0001). Cellular target engagement for MTX652 was confirmed in HeLa-YFP-Parkin cells with an EC 50 of 2.7 nM ( n =2). Furthermore, the USP30 substrate TOM20 was ubiquitinated following MTX652 treatment in vitro (EC 50 =6.1 nM, n =4) providing evidence of mitophagy activation, a finding also confirmed in mouse heart tissue (MTX652, 5mg/kg). Conclusions: The USP30 inhibitor, MTX652 significantly protected mice from TAC induced cardiac hypertrophy and LV dysfunction. Furthermore, MTX652 potentiates ubiquitylation of TOM20 as a mechanism to promote mitophagy. These data suggest our clinical stage molecule could provide a novel therapeutic approach for the treatment of cardiac hypertrophy and heart failure.

Abstract 4134967: Pericardial Adipose Tissue Hypertrophy Contributes to Heart Failure via β3 Adrenergic Signaling-Mediated Activation of the TGFβ1 Pathway

Background: The heart is surrounded by pericardial adipose tissue (PeAT). An increase in PeAT volume has been associated with the development of heart failure; however, the precise molecular mechanisms by which hypertrophic PeAT contributes to heart failure remain to be elucidated. Aims: To clarify the involvement of PeAT hypertrophy in the development of heart failure. Methods: Male C57BL/6 mice (8-10 weeks old) were fed a high-fat diet (HFD) for 8 weeks to induce PeAT hypertrophy. Cardiac pressure overload was induced by transverse aortic constriction (TAC) with a 26-gauge needle. Results: PeAT volume significantly increased in HFD-fed mice compared to those on a normal diet (ND) (25.28 ± 4.1 mg vs. 9.35 ± 0.73 mg, p<0.01). Eight weeks after TAC, HFD-fed mice (TAC+HFD) exhibited more pronounced cardiac dysfunction (fractional shortening: 45.21 ± 2.21% vs. 55.99 ± 1.91%, p=0.002, left ventricular mass: 130.3 ± 7.80% vs. 106.8 ± 3.77%, p=0.0154), upregulation of cardiac fibrosis-related genes ( Col1a1 , Col3a1 ), and greater fibrotic area in the left ventricle compared to ND-fed TAC mice (TAC+ND). Simultaneously, the TGFβ/Smad pathway was activated in the left ventricles of TAC+HFD mice. Notably, surgical removal of hypertrophic PeAT improved cardiac function in TAC+HFD mice, while transplantation of PeAT from HFD-fed mice into TAC+ND mice worsened cardiac function. In TAC+HFD mice, local noradrenaline concentration in PeAT decreased, along with reduced activation of hormone-sensitive lipase, a downstream target of β3 adrenergic receptor signaling. Local free fatty acid concentrations also decreased in the PeAT of HFD-fed mice. In the RAW 264.7 macrophage cell line, a decrease in palmitic acid, a major fatty acid, led to increased expression of TGFβ1. Conclusions: These results suggest that HFD-induced PeAT hypertrophy suppresses β3 adrenergic receptor signaling and free fatty acid release, increasing TGFβ1 expression in the macrophages and resulting in cardiac fibrosis and dysfunction. Our findings provide new insights into the pathogenesis of PeAT hypertrophy in heart failure development.

Assessment of the Sokolow Lyons Criteria of Left Ventricular Hypertrophy in Comparison with Echocardiography in Hypertensive Patients

Around 65.4% of people over the age of 60 have hypertension, and it's the underlying cause of 6% of all fatalities globally. The left ventricle enlarges, or hypertrophies, in people with hypertension. If the left ventricle of the heart thickens its walls or the chamber of the left ventricle expands, or if both happen at once, the condition is called left ventricular hypertrophy (LVH) [1]. This condition impacts approximately 15 -20% of the general population and has similar rates in men and women. Serious health complications such as cardiovascular diseases, stroke, congestive heart failure, irregular heart rhythms (ventricular arrhythmias), and sudden cardiac death are linked to it.Rationale of the study: In people with slightly hypertensive conditions, the prevalence of LVH is 20%; in those with severe or complex hypertension, it approaches 100%. LVH is also a result of valve disorders, which cause pressure and/or volume overload. Furthermore, "physiological" LVH—which occurs in well-trained athletes in reaction to job overload—can arise. About 0.2% of the general population has hypertrophic cardiomyopathy, a hereditary condition caused by mutations in the sarcomere protein genes. It is characterized by severe cardiac tissue disarray, fibrotic scarring, and aberrant internal coronary arteries.Background and statement of the problem: Hypertension is a leading cause of many cardiovascular problems and cerebrovascular accidents Aim: Assessment of the Sokolowlyon’s Criteria of Left Ventricular Hypertrophy in comparison with Echocardiography Inhypertensives PatientsObjective: To determine whether the ECHO of left ventricular hypertrophy significantly coincides with the Sokolow Lyon criterion of the ECG.Methodology: This cross-sectional study was carried out at the Shree Balaji Medical College and Hospital's general medicine department in Chromepet, Tamil Nadu, India. The study ran from June 2022 to December 2023, a duration of eighteen months.Results: The study focused on assessing the correlation between Sokolow-Lyon criteria on (ECG) and (LVH) as determined by echocardiography (ECHO). The results revealed that among the 125 participants, 88 cases (70.40%) were identified as having LVH based on Sokolow-Lyon criteria, while 37 cases (29.60%) showed no signs of LVH. These findings provide a quantitative breakdown of the prevalence of LVH according to ECG criteria within the study population.Conclusion: Our investigation's findings showed that the ECG LVH Sokolow Lyon criteria had a satisfactory level of specificity and sensitivity in the diagnosis of left ventricular hypertrophy (LVH). The most sensitive diagnostic criteria turned out to be the ECG LVH Sokolow Lyon criteria, especially when it came to patients with co-morbidities. We found that the Sokolow Lyon criteria had a 36% sensitivity in the current investigation. As such, we suggest applying these criteria to assist in verifying the diagnosis of LVH, particularly in low-complexity healthcare environments without image-based diagnostic techniques like MRI and ECHO.

PINK1-mediated mitophagy attenuates pathological cardiac hypertrophy by suppressing the mtDNA release-activated cGAS-STING pathway.

Sterile inflammation is implicated in the development of heart failure (HF). Mitochondria plays important roles in triggering and maintaining inflammation. Mitophagy is important for regulation of mitochondrial quality and maintenance of cardiac function under pressure overload. The association of mitophagy with inflammation in HF is largely unclear. As PINK1 is a central mediator of mitophagy, our objective was to investigate its involvement in cardiac hypertrophy, and the effect of PINK1-mediated mitophagy on cGAS-STING activation during cardiac hypertrophy. PINK1 knockout and cardiac-specific PINK1-overexpressing transgenic mice were created and subsequently subjected to transverse aortic constriction (TAC) surgery. In order to explore whether PINK1 regulates STING-mediated inflammation during HF, PINK1/STING (stimulator of interferon genes) double-knockout mice were created. Pressure overload was induced by TAC. Our findings indicate a significantly decline in PINK1 expression in TAC-induced hypertrophy. Cardiac hypertrophic stimuli caused the release of mitochondrial DNA (mtDNA) into the cytosol, activating the cGAS-STING signaling, which in turn initiated cardiac inflammation and promoted the progression of cardiac hypertrophy. PINK1 deficiency inhibited mitophagy activity, promoted mtDNA release, and then drove the overactivation of cGAS-STING signaling, exacerbating cardiac hypertrophy. Conversely, cardiac-specific PINK1 overexpression protected against hypertrophy thorough inhibition of the cGAS-STING signaling. Double-knockout mice revealed that the effects of PINK1 on hypertrophy were dependent on STING. Our findings suggest that PINK1-mediated mitophagy plays a protective role in pressure overload-induced cardiac hypertrophy via inhibiting the mtDNA-cGAS-STING pathway.

USP20 deletion promotes eccentric cardiac remodeling in response to pressure overload and increases mortality.

Left ventricular hypertrophy (LVH) caused by chronic pressure overload with subsequent pathological remodeling is a major cardiovascular risk factor for heart failure and mortality. The role of deubiquitinases in LVH has not been well characterized. To define whether the deubiquitinase ubiquitin-specific peptidase 20 (USP20) regulates LVH, we subjected USP20 knockout (KO) and cognate wild-type (WT) mice to chronic pressure overload by transverse aortic constriction (TAC) and measured changes in cardiac function by serial echocardiography followed by histological and biochemical evaluations. USP20-KO mice showed severe deterioration of systolic function within 4 wk of TAC compared with WT cohorts. Both USP20-KO TAC and WT-TAC cohorts presented cardiac hypertrophy following pressure overload. However, USP20-KO-TAC mice showed an increase in cardiomyocyte length and developed maladaptive eccentric hypertrophy, a phenotype generally observed with volume overload states and decompensated heart failure. In contrast, WT-TAC mice displayed an increase in cardiomyocyte width, producing concentric remodeling that is characteristic of pressure overload. In addition, cardiomyocyte apoptosis, interstitial fibrosis, and mouse mortality were augmented in USP20-KO-TAC compared with WT-TAC mice. Quantitative mass spectrometry of LV tissue revealed that the expression of sarcomeric myosin heavy chain 7 (MYH7), a fetal gene normally upregulated during cardiac remodeling, was significantly reduced in USP20-KO after TAC. Mechanistically, we identified increased degradative lysine-48 polyubiquitination of MYH7 in USP20-KO hearts, indicating that USP20-mediated deubiquitination likely prevents protein degradation of MYH7 during pressure overload. Our findings suggest that USP20-dependent signaling pathways regulate the layering pattern of sarcomeres to suppress maladaptive remodeling during chronic pressure overload and prevent cardiac failure.NEW & NOTEWORTHY We identify ubiquitin-specific peptidase 20 (USP20) as an important enzyme that is required for cardiac homeostasis and function, particularly during myocardial pressure overload. USP20 regulates protein stability of cardiac MYH7, an essential molecular motor protein expressed in sarcomeres; loss-of-function mutations of MYH7 are associated with human hypertrophic cardiomyopathy, cardiac failure, and sudden death. Enhancing USP20 activity could be a potential therapeutic approach to prevent the development of maladaptive state of eccentric hypertrophy and heart failure.

Investigating the Catastrophic Roof Failure of a Fatty Acid Storage Tank: Causes, Mechanisms, and Safety Implications

This paper investigates the catastrophic failure of the roof weld on a carbon steel storage tank at a Fatty Acids plant, which was attributed to pressure overload. The incident resulted in the tank's roof, weighing over 5 tons and spanning 8 meters in diameter, being propelled 25 meters from the tank. Despite installing several safety devices, including pressure regulating valves, pressure indicator controls, and pressure vacuum relief valves, inadequate maintenance led to their malfunction. This study examines the mechanisms and causes behind the failure, highlighting the crucial role of regular maintenance in ensuring the functionality of safety instruments. While neither toxic nor flammable, the plant's compressed air system poses a significant hazard due to the energy stored at slight overpressure, necessitating vigilant management by the safety department. The findings underscore the importance of robust maintenance strategies and procedural adherence to prevent similar incidents, enhancing industrial storage systems' overall safety and reliability.

Heart failure with preserved ejection fraction in pigs causes shifts in posttranscriptional checkpoints.

Left ventricular pressure overload (LVPO) can lead to heart failure with a preserved ejection fraction (HFpEF) and LV chamber stiffness (LV Kc) is a hallmark. This project tested the hypothesis that the development of HFpEF due to an LVPO stimulus will alter posttranscriptional regulation, specifically microRNAs (miRs). LVPO was induced in pigs (n = 9) by sequential ascending aortic cuff and age- and weight-matched pigs (n = 6) served as controls. LV function was measured by echocardiography and LV Kc by speckle tracking. LV myocardial miRs were quantified using an 84-miR array. Treadmill testing and natriuretic peptide-A (NPPA) mRNA levels in controls and LVPO were performed (n = 10, n = 9, respectively). LV samples from LVPO and controls (n = 6, respectively) were subjected to RNA sequencing. LV mass and Kc increased by over 40% with LVPO (P < 0.05). A total of 30 miRs shifted with LVPO of which 11 miRs correlated to LV Kc (P < 0.05) that mapped to functional domains relevant to Kc such as fibrosis and calcium handling. LVPO resulted in reduced exercise tolerance (oxygen saturation, respiratory effort) and NPPA mRNA levels increased by fourfold (P < 0.05). RNA analysis identified several genes that mapped to specific miRs that were altered with LVPO. In conclusion, a specific set of miRs are changed in a large animal model consistent with the HFpEF phenotype, were related to LV stiffness properties, and several miRs mapped to molecular pathways that may hold relevance in terms of prognosis and therapeutic targets.NEW & NOTEWORTHY Heart failure with preserved ejection fraction (HFpEF) is an ever-growing cause for the HF burden. HFpEF is particularly difficult to treat as the mechanisms responsible for this specific form of HF are poorly understood. Using a relevant large animal model, this study uncovered a unique molecular signature with the development of HFpEF that regulates specific biological pathways relevant to the progression of this ever-growing cause of HF.

Assessment of experimental circulating biomarkers in volume and pressure overload: insights from a cohort study

Abstract Introduction Experimental biomarkers including Angiopoietin-2 (ANG2), bone morphogenetic protein 10 (BMP10), fibroblast growth factor 23 (FGF23), and insulin-like growth factor-binding protein 7 (IGFBP7) are hypothesized to reflect cardiac pathophysiological processes that are potentially present in adverse cardiac remodeling in volume or pressure overload. This study aims to elucidate the relationship between these circulating biomarkers and the presence of hemodynamically significant pressure or volume overload and adverse outcomes and compare it to N-terminal pro B-type natriuretic peptide (NT-proBNP). Methods We studied the association between the four experimental circulating biomarkers in patients with pressure or volume overload with reference to none/mild valvular disease in N=1302 of an observational outpatient cardiology cohort. The median age was 63.0 (25th/75th quartile 51.5, 71.4) years, 445 (34.2%) were women. Circulating biomarkers were quantified using a novel antibody-based method. Logistic regression models with cox regression plots were employed to assess the association of each biomarker with the severity of valve disease concerning volume or pressure overload, adjusted for age and sex. Results In the overall population, elevated levels of ANG2, BMP10, FGF23 and IGFB7 were positively associated with the presence of significant volume overload (ANG2: Odds ratio (OR) 1.26 (95% confidence interval (CI) 1.17-1.35), p&amp;lt;0.001; BMP10: OR 2.57 (CI 1.89-3.48), p&amp;lt;0.001; FGF23: OR 1.51 (CI 1.14-1.20), p=0.004; IGFBP7: OR 1.39 (CI 1.14-1.69), p=0.001, NT-proBNP: OR 1.69 (CI 1.47-1.95), p&amp;lt;0.001). No statistically significant association between circulating biomarkers and pressure overload was observed. Over a median follow-up of 4 years, 31 (20.1%) participants died in the group of volume overload and 9 (40.9%) individuals in the group of pressure overload. After multivariable-adjustment, elevated levels of BMP 10 showed a borderline association with an increased risk of all-cause mortality in individuals with volume overload compared to none/mild valvular disease: hazard ratio (HR) 1.51 (CI 0.96- 2.38), p=0.075. Higher concentrations of all biomarkers were predictive of all-cause mortality for both individuals with volume overload and those with none/mild valvular disease (ANG2: HR 3.72 (CI 1.67-8.33), p=0.001; BMP10: HR 1.65 (CI 1.20-2.26), p=0.002; FGF23: HR 2.08 (CI 1.65-2.62), p&amp;lt;0.001; IGFBP7: HR 1.55 (CI 1.25-1.91), p&amp;lt;0.001; NT-proBNP: HR 1.72 (CI 1.47-2.00), p&amp;lt;0.001). Conclusions This study demonstrates that circulating biomarkers involved in distinct pathophysiological pathways of inflammation, fibrosis and calcification are elevated in patients with hemodynamically significant volume overload. Since they are also related to mortality, their clinical role needs to be explored further, also in context with the routine biomarker NT-proBNP.

Cardiac secreted-HSP90alpha in cardiomyocyte hypertrophy by N-Cadherin mediated signaling under pressure overload

Abstract Background Left ventricular hypertrophy (LVH) in response to pressure overload is strongly associated with adverse cardiovascular outcomes. Heat shock protein 90 (HSP90) has been reported to be involved in cardiac remodeling under stress. Aims Here, we evaluate whether serum HSP90α (an isoform of HSP90) increases and associates with cardiac hypertrophy in patients with hypertension or severe aortic stenosis (AS), and explore the potential mechanisms in experimental pressure overload mouse model. Methods Serum HSP90α levels in patients with hypertension or aortic stenosis (AS) were determined by ELISA. Pressure overload mouse model was built by a transverse aortic constriction (TAC). Cardiac function was assessed by echocardiography. Cardiac hypertrophy was examined by histology, western blot and RNA analysis. Results Serum levels of HSP90α were higher in patients with hypertension or AS than in the control group, respectively, and the levels positively correlated with LVH. HSP90α levels also increased in heart tissues of patients with obstructive hypertrophic cardiomyopathy (HCM), and mice after TAC, in parallel with the hypertrophic markers. TAC induced the enhanced expression and secretion of HSP90α from cardiomyocytes and cardiac fibroblasts. Knockdown of HSP90α or blockade of extracellular HSP90α (eHSP90α) prevent the development of LVH under pressure overload in vivo and in vitro. By Nano-HPLC-MS/MS analysis, we identified eHSP90α interacted with N-cadherin in cardiomyocyte surface, which induced the activation of β-catenin and promoted β-catenin to bind TCF7 (a member of TCF/Lef family) in nucleus, enhanced the transcription of hypertrophic genes, contributing to cardiac hypertrophy and dysfunction under pressure overload. Conclusions Our data demonstrated that cardiac secreted-HSP90α promoted myocardial hypertrophy by N-Cadherin mediated β-catenin/TCF7 signaling under pressure overload. It indicates the therapeutic potential of targeting HSP90α-initiated signaling against cardiac hypertrophy and dysfunction under pressure overload.