Myocardial Inflammation Research Articles

20S-O-Glc-DM treats metabolic syndrome-induced heart failure through regulating gut flora

Heart failure is a multifactorial disease, the percentage of patients with heart failure caused by metabolic syndrome is increasing year by year. The effect of gut flora dysbiosis on metabolic syndrome and heart failure has received widespread attention in recent years. Drugs to treat the condition urgently need to be discovered. C20DM, as a precursor compound of ginsenoside, is a small molecule compound obtained by biosynthetic means and is not available in natural products. In this project, we found that C20DM could improve the diversity of gut flora and elevate the expression of intestinal tight junction proteins-Occludin, Claudin, ZO-1, which inhibited the activity of the TLR4-MyD88-NF-kB pathway, and as a result, reduced myocardial inflammation and slowed down heart failure in metabolic syndrome mice. In conclusion, our study suggests that C20DM can treat heart failure by regulating gut flora, and it may be a candidate drug for treating metabolic syndrome-induced heart failure.

Cardiac magnetic resonance for ventricular arrhythmias: a systematic review and meta-analysis

BackgroundCardiac magnetic resonance (CMR) allows comprehensive myocardial tissue characterisation, revealing areas of myocardial inflammation or fibrosis that may predispose to ventricular arrhythmias (VAs). With this study, we aimed to estimate...

Predictive role of hematological indices in patients with acute coronary syndrome in Ethiopia: Intrahospital outcomes

BackgroundApart from troponins, various additional biomarkers that indicate myocardial injury, inflammation, thrombosis, and other routes are being studied to improve the treatment of acute coronary syndrome (ACS). Myeloid activity has been found to be elevated in ACS, and this has sparked a great deal of interest in hematological parameters since they might offer independent insights into pathophysiology and risk assessment. ObjectiveThe purpose of this study was to evaluate the hematological markers' prognostic ability for all intrahospital causes of mortality in individuals with an ACS diagnosis. MethodsA long-term cohort study based at an institution was done. At Jimma Medical Center, patients with an ACS diagnosis were progressively brought in between May 1, 2022, and October 31, 2023. Complete blood counts (CBC) and biochemical analysis were carried out. Multilevel mixed effect logistic regression was computed to evaluate the predictive competence of hematological indices on intrahospital mortality. Prognostic performance of hematological parameters was done using the ROC curve analysis. ResultA total of 110 patients were included, of which 99 (90 %) were diagnosed ST-elevation myocardial infarction, and 74 (67.3 %) were men. The mean age was 56 (±11) years. RDW, platelet count, and MCV were independently associated with intrahospital mortality (AOR = 1.20 with P < 0.001, AOR = 0.995 with P < 0.03, and AOR = 0.897 with P < 0.025, respectively). The predictive power of RDW-SD for intrahospital mortality was evaluated by ROC analysis, the AUC value were 0.737 (95 % CI 0.669–0.805). ConclusionThis study found that red cell distribution width, mean corpuscular volume, and platelets were predictive factors for intrahospital death in patients with ACS. Thus, it is possible to predict the prognosis of an ACS patient using hematological data.

Sanggenol L Reduces LPS-induced Myocardial Injury and Inflammation by Activating PI3K/AKT/mTOR and Inhibiting NF-κB in Rats

Sanggenol L Reduces LPS-induced Myocardial Injury and Inflammation by Activating PI3K/AKT/mTOR and Inhibiting NF-κB in Rats

Cardamonin intervenes in myocardial hypertrophy progression by regulating Usp18

BackgroundMyocardial hypertrophy is a chronic cardiac condition that often occurs from long-term pressure or volumetric load on the heart. Propranolol hydrochloride has been employed in research on hypertension, pheochromocytoma, myocardial infarction, arrhythmias, angina pectoris, and hypertrophic cardiomyopathy. Current treatments for this condition have side effects, such as arrhythmias and myocardial cell death, thus necessitating safer and more effective alternatives. Recently, natural products have gained attention in drug development because of their low toxicity and high efficacy. Cardamonin, a compound derived from Chinese herbal materials, has shown potential in inhibiting oxidative stress and inflammation, which is beneficial for cardiovascular health. Nevertheless, the impact on myocardial hypertrophy and cardiac remodeling is still uncertain MethodsApproach We employed a transverse aortic constriction (TAC)model to simulate the pathological conditions of myocardial hypertrophy. Mice were administered varying doses of CAR (10 and 40 mg kg-1/d), and cardiac function was assessed using techniques such as echocardiography, qPCR, Masson staining, DHE staining, immunofluorescence, and immunohistochemistry. Propranolol hydrochloride was the positive control for observing the anti-myocardial hypertrophic effects of CAR. ResultsCardamonin significantly reduced TAC-induced myocardial hypertrophy, fibrosis, inflammation, and oxidative stress. High CAR concentrations showed better anti-myocardial remodeling effects. The anti-hypertrophic effect of cardamonin was similar to that of propranolol hydrochloride. Further investigating the mechanism of action revealed that ubiquitin-specific peptidase (USP)18, a deubiquitnating enzyme that regulates various cellular signaling pathways, was a key downstream regulator affected by cardamonin. To confirm this, AAV9-cTNT-Usp18 and Usp18 myocardial-specific knockout mice were generated and treated with TAC. Usp18 downregulation was found to interfere with the protective effects of CAR against myocardial remodeling, whereas its overexpression enhanced these effects. ConclusionThis study used propranolol as a positive control and provided the first in-depth exploration of the concentration-dependent effects of cardamonin on myocardial hypertrophy and cardiac remodeling. CAR is a new candidate drug for cardiovascular disease treatment. This comparative study provides evidence for assessing the clinical application potential of new drugs and delves into its mechanisms of action, particularly the interaction with Usp18. Comprehending these mechanisms is beneficial for formulating more targeted future treatment approaches.

An engineered human cardiac tissue model reveals contributions of systemic lupus erythematosus autoantibodies to myocardial injury

Systemic lupus erythematosus (SLE) is a heterogenous autoimmune disease that affects multiple organs, including the heart. The mechanisms of myocardial injury in SLE remain poorly understood. In this study, we engineered human cardiac tissues and cultured them with IgG from patients with SLE, with and without myocardial involvement. IgG from patients with elevated myocardial inflammation exhibited increased binding to apoptotic cells within cardiac tissues subjected to stress, whereas IgG from patients with systolic dysfunction exhibited enhanced binding to the surface of live cardiomyocytes. Functional assays and RNA sequencing revealed that, in the absence of immune cells, IgG from patients with systolic dysfunction altered cellular composition, respiration and calcium handling. Phage immunoprecipitation sequencing (PhIP-seq) confirmed distinctive IgG profiles between patient subgroups. Coupling IgG profiling with cell surfaceome analysis identified four potential pathogenic autoantibodies that may directly affect the myocardium. Overall, these insights may improve patient risk stratification and inform the development of new therapeutic strategies.

Targeting Cyclophilin A in the Cardiac Microenvironment Preserves Heart Function and Structure in Failing Hearts.

Cardiac hypertrophy is characterized by remodeling of the myocardium, which involves alterations in the ECM (extracellular matrix) and cardiomyocyte structure. These alterations critically contribute to impaired contractility and relaxation, ultimately leading to heart failure. Emerging evidence implicates that extracellular signaling molecules are critically involved in the pathogenesis of cardiac hypertrophy and remodeling. The immunophilin CyPA (cyclophilin A) has been identified as a potential culprit. In this study, we aimed to unravel the interplay between eCyPA (extracellular CyPA) and myocardial dysfunction and evaluate the therapeutic potential of inhibiting its extracellular accumulation to improve heart function. Employing a multidisciplinary approach encompassing in silico, in vitro, in vivo, and ex vivo experiments we studied a mouse model of cardiac hypertrophy and human heart specimen to decipher the interaction of CyPA and the cardiac microenvironment in highly relevant pre-/clinical settings. Myocardial expression of CyPA (immunohistology) and the inflammatory transcriptome (NanoString) was analyzed in human cardiac tissue derived from patients with nonischemic, noninflammatory congestive heart failure (n=187). These analyses were paralleled by a mouse model of Ang (angiotensin) II-induced heart failure, which was assessed by functional (echocardiography), structural (immunohistology, atomic force microscopy), and biomolecular (Raman spectroscopy) analyses. The effect of inhibiting eCyPA in the cardiac microenvironment was evaluated using a newly developed neutralizing anti-eCyPA monoclonal antibody. We observed a significant accumulation of eCyPA in both human and murine-failing hearts. Importantly, higher eCyPA expression was associated with poor clinical outcomes in patients (P=0.043) and contractile dysfunction in mice (Pearson correlation coefficient, -0.73). Further, myocardial expression of eCyPA was critically associated with an increase in myocardial hypertrophy, inflammation, fibrosis, stiffness, and cardiac dysfunction in vivo. Antibody-based inhibition of eCyPA prevented (Ang II)-induced myocardial remodeling and dysfunction in mice. Our study provides strong evidence of the pathogenic role of eCyPA in remodeling, myocardial stiffening, and dysfunction in heart failure. The findings suggest that antibody-based inhibition of eCyPA may offer a novel therapeutic strategy for nonischemic heart failure. Further research is needed to evaluate the translational potential of these interventions in human patients with cardiac hypertrophy.

Thromboxane A2 blockade attenuates ethanol-induced myocardial inflammation: Sipping from the same bottle.

Thromboxane A2 blockade attenuates ethanol-induced myocardial inflammation: Sipping from the same bottle.

Eosinophilic Granulomatous Polyangitiis- a hopeful outcome of a Sinister disease- a case report

Eosinophilic myocarditis is a rare form of myocardial inflammation characterized by eosinophilic infiltration and often accompanied by eosinophilia. It can be fatal in in its initial presentation. Although the condition is rare, it’s quite variable in terms of clinical presentation and prognosis ranging from fulminant myocarditis to uneventful recovery. We present a case of a young female patient with eosinophilic myocarditis who had favorable outcome after treatment with steroid and immunosuppressive agents. Cardiovasc j 2024; 16(2): 102-104

Multiparametric Cardiac Magnetic Resonance Imaging to Discriminate Endomyocardial Biopsy-Proven Chronic Myocarditis From Healed Myocarditis

BackgroundDetecting ongoing inflammation in myocarditis patients has prognostic relevance, but there are limited data on the detection of chronic myocarditis and its differentiation from healed myocarditis. ObjectivesThis study sought to assess the performance of cardiac magnetic resonance (CMR) for the detection of ongoing inflammation and the discrimination of chronic myocarditis from healed myocarditis. MethodsConsecutive patients with persistent symptoms (>30 days) suggestive of myocarditis were prospectively enrolled from a single tertiary center. All patients underwent a multiparametric 1.5-T CMR protocol including biventricular strain, T1/T2 mapping, and late gadolinium enhancement (LGE). Endomyocardial biopsy was chosen for the reference standard diagnosis. ResultsAmong 452 consecutive patients, 103 (median age: 50 years; 66 men) had evaluable CMR and cardiopathologic reference diagnosis: 53 (51%) with chronic lymphocytic myocarditis and 50 (49%) with healed myocarditis. T2 mapping as a single parameter showed the best accuracy in detecting chronic myocarditis, if abnormal in ≥3 segments (92%; 95% CI: 85-97), and provided the best discrimination from healed myocarditis, as defined by the area under the receiver-operating characteristic curve (0.87 [95% CI: 0.79-0.93]; P < 0.001), followed by radial peak systolic strain rate of the left ventricle (0.86) and the right ventricle (0.84); T1 mapping (0.64), extracellular volume fraction (0.62), and LGE (0.57). Specificity increased when T2 mapping was combined with elevation of either troponin or C-reactive protein. ConclusionsA multiparametric CMR protocol allows detection of ongoing myocardial inflammation and discrimination of chronic myocarditis from healed myocarditis, with segmental T2 mapping and biventricular strain analysis showing higher diagnostic accuracy compared with T1 mapping, extracellular volume fraction, and LGE. The use of biomarkers (troponin or C-reactive protein) may improve specificity.

Abstract Or120: CD40 is an immune checkpoint regulator that potentiates myocardial inflammation through activation and expansion of CCR2 + macrophages and CD8 T-cells

Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1/PD-L1, CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here, we leveraged genetic mouse models, single cell sequencing, and cell depletion studies to demonstrate that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2 + macrophages and subsequent recruitment of effector memory CD8 T-cells. We identify a positive feedback loop between CCR2 + macrophages and CD8 T-cells driven by IL12b, TNF, and IFN-γ signaling that promotes myocardial inflammation and show that prior exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates LV remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.

Abstract We097: Dual Targeting CXCR4 and CXCR7 Prevents Doxorubicin-Induced Cardiotoxicity by Eliminating Cardiac Inflammation and Preserving Cardiomyocyte Function

Background: Doxorubicin (DOX)-induced cardiotoxicity (DICT) has become a serious health burden for cancer survivors. The detrimental effects of CXCR4-mediated excessive inflammation in myocardium and the protective effects of CXCR7 in cardiomyocytes have been demonstrated. Aims: We tested the protective effects against DICT of a dual-targeting compound TC14012, which has specific antagonistic activity against CXCR4 and potent agonistic activity on CXCR7. Methods: Eight-week-old male C57BL/6J mice were injected with DOX for consecutive 5 weeks, during which mice were treated with TC14012 twice a week. One week after the last dose injection, mice were euthanized after heart function examination. Markers of cardiac inflammation and fibrosis were evaluated. Cardiac RNA-seq was performed to explore the underlying molecular pathways. Key findings: TC14012 supplement significantly prevented DOX-induced cardiac systolic dysfunction, reflected by improved ejection fraction and fraction shortening, along with remarkable attenuation of DOX-induced cardiac perivascular and interstitial collagen deposition and neutrophils and macrophage infiltration. RNA-seq revealed that TC14012 prevention of DICT was accompanied with a remarkable stimulation of signals involving in cardiac contraction and energy reserve metabolic process, particularly glycogen and glucan metabolism that are crucial for meeting the cardiac energy demand in response to DOX induction. These signals could be further enriched into AMPK signaling pathway and validated by upregulation of AMPK phosphorylation. Besides, TC14012 prevention of DICT was accompanied with a significant reduction in cardiac mast cell activation and degranulation. These signals could be further enriched into Rap1 signaling pathway, and TC14012 was validated to inhibit Rap1 activity and mast cell activation. Most importantly, TC14012 treatment did not affect the suppressive effects of DOX on tumor growth in a syngeneic EL4 lymphoma-bearing, immunocompetent mouse model. Conclusions: We preliminary conclude that TC14012 prevents DICT by activating cardiac CXCR7 to reprogram cardiomyocyte metabolism and prevent cardiac damage and dysfunction via activating AMPK, and by antagonizing CXCR4 to inhibit cardiac mast cell infiltration and activation via blunting Rap1 activity but does not affect the anti-tumor activity of DOX.

Abstract Mo017: CXCR3: A Tumor-Conscious Target to Treat Immunotherapy-Induced Myocarditis

Introduction: Immune checkpoint inhibitors (ICIs, such as anti-CTLA-4 or anti-PD-1) have especially been effective in cancer therapies. However, ICIs treatment can result in myocarditis, the most serious complication of ICIs, which has a case fatality rate as high as 40%. Here, we investigate CXCR3 blockade for targeted treatment of myocardial inflammation in ICI myocarditis while considering concurrent tumor treatment. We hypothesize that CXCR3 blockade will have a direct effect on reducing CD8+ T-cell mediated cardiomyocyte cardiotoxicity without affecting tumor treatment. Methods: To study the impact of CXCR3 blockade on myocardial inflammation, we established an in vitro cardiomyocyte apoptosis model by co-culturing cardiomyocytes and MRL-WT mice CD8+ T-cells with/without ICI stimulation or MRL- Pdcd1-/- mice CD8+ T-cells. We then blocked CXCR3 to assess the effect on CD8+ T cell-mediated cytotoxicity against cardiomyocytes. To assess CXCR3 blockade in an in vivo model of ICI myocarditis accounting for tumor, we treated MRL mice inoculated with B16F1 melanoma cells with six doses of 400 µ g each of anti-PD1 and anti-CTLA4 and investigated the effects of CXCR3-CXCL9/10 blockade on hearts and tumors. Results: In vitro CD8+ T-cell and cardiomyocyte co-culture demonstrated mitigation of cardiomyocytes apoptosis with CXCR3 blockade ( Fig. 1 A - C) , suggesting decreased CD8+ T-cell cytotoxicity with CXCR3 blockade. In vivo treatment with dual immunotherapy (anti-PD1/anti-CTLA4 monoclonal antibodies) in the tumor MRL mouse model demonstrated significant tumor volume reduction, which was not impacted by concurrent treatment with anti-CXCR3 or anti-CXCL9/10 (Fig. 1 D - F) . Concurrently, myocarditis occurred in the group treated with immunotherapy alone, not in anti-CXCL9/10 or anti-CXCR3 (Fig. 1 G - H). Conclusions: CXCR3 blockade reduces CD8+ T-cell cytotoxicity against cardiomyocytes and mitigates myocarditis in an in vivo tumor ICI myocarditis mouse model without affecting anti-tumor ICI efficacy, positioning CXCR3 as a promising target for therapeutic intervention.

Protective effect of sevoflurane on myocardial ischemia-reperfusion injury: a systematic review and meta-analysis.

Myocardial ischemia-reperfusion (I/R) injury significantly impacts recovery in both cardiac and non-cardiac surgeries, potentially leading to severe cardiac dysfunction. Sevoflurane, a volatile anesthetic, is reputed for its protective effects against myocardial I/R injury, although evidence remains inconclusive. This systematic review and meta-analysis aim to clarify the cardioprotective efficacy of sevoflurane. The systematic search of databases including Medline, Embase, Scopus, and Web of Science, was supplemented with a manual search to retrieve studies using rat or mouse models of myocardial I/R injury, comparing sevoflurane pretreatment (≥ 24 hours before I/R), preconditioning (within 24 hours before I/R), or post-conditioning (after I/R) against non-treated controls. The outcomes were cardiac function, myocardial infarct size, apoptosis, inflammation, oxidative stress, and cardiac biomarkers. Using the random effects model, standardized mean differences (SMD) were pooled to perform meta-analyses. Fifty-one studies, encompassing 8189 subjects, were included in the meta-analysis. Pretreatment with Sevoflurane significantly reduced infarct size. Sevoflurane preconditioning exhibited positive effects on left ventricular parameters and ejection fraction, and reduced infarct size, apoptosis, and oxidative stress. Post-conditioning with Sevoflurane demonstrated improvements in cardiac function, including enhanced left ventricular parameters and reduced infarct size, apoptosis, inflammation, oxidative stress, and cardiac biomarkers. Sevoflurane demonstrates a significant protective effect against myocardial I/R injury in animal models. These findings support the potential clinical utility of sevoflurane as an anesthetic choice in preventing and managing myocardial I/R injury during surgeries.

Abstract Mo015: Myeloid Specific PD-L1 Deletion Promotes Cardiac Dysfunction And Myocardial Inflammation

Background: Immunotherapy, particularly PD-1/PD-L1 blockers, is effective in cancer treatment but can cause rare, but potentially fatal heart issues. Despite the significant impact of these adverse events, there is limited research into the underlying mechanisms of immune checkpoint inhibitor (ICI)-mediated cardiotoxicity. PD-L1, which is abundantly expressed in cardiac tissue, particularly exhibits high expression levels over myeloid cells. However, the precise role of myeloid-specific PD-L1 signaling in mediating autoimmune cardiac disease pathology remains unclear. Methods and Results: To study the role of myeloid cell-specific PD-L1 (myeloid-PD-L1) in cardiac pathophysiology, we generated myeloid-specific PD-L1 KO mice, using Lyz2tm1(Cre) Ifo systems. As expected, PD-L1 expression was significantly down-regulated in Mφs from myeloid-PD-L1 KOs. The cardiac function was followed by echocardiography. Controls and myeloid-PD-L1-KO hearts had comparable ventricular function at 1 month of age. Interestingly, as early as 2 months of age, myeloid-PD-L1-KOs displayed marked cardiac dysfunction as reflected by reduced LVEF, LVFS, and HF markers. Immune profiling was conducted whether chronic inflammation contributes to cardiac dysfunction and remodeling at a later age as observed at 2 and 3 months of age. Interestingly, excessive systemic inflammation and substantial immune infiltration (innate and adoptive), activation, and a pro-inflammatory cytokine storm were detected in the KO hearts. Furthermore, myeloid-PD-L1 KO hearts showed increased recruitment of pro-inflammatory CCR2+ monocytes and macrophages. Conclusion: Our data with myeloid-PD-L1 KOs suggest that deleting PD-L1 in myeloid lineage promotes myocardial and systemic inflammation through innate and adaptive immune cell activation and recruitment of CCR2+ MΦs. Subsequently, this leads to impaired cardiac pathophysiology. Thus, these translational studies will directly evaluate the potential of targeting myeloid-PD-L1 signaling to alleviate cardiac damage.

Abstract Mo010: Evidence for cardiomyocyte dysfunction in cancer-induced cachexia in mice

Background: There is currently no therapy targeting cancer-related cardiomyopathy and treatment of heart failure in the oncological setting is nonspecific. Moreover, cancer is often assocaited with cachexia and the pathophysiology of cancer-cachexia induced cardiac (dys)functions are not fully known. Methods: Colon-26 adenocarcinoma (C26; n=30) or shIL-6 (C26 shIL-6; n=30) cells were inoculated subcutaneously into the flank of syngeneic adult male BALB/cmice, meanwhile control mice were injected with PBS (n=25). Twenty days after the cells injection, cardiac function was assessed using transthoracic echocardiography, ex vivo isolated working heart methods. In addition, intracellular Ca 2+ transient and force-calcium relationships were assessed in isolated single ventricular cardiomyocytes (CMs). Cardiac inflammation, metabolism and fibrosis were also assessed. Results: Despite that tumor size was comparable between the cancer groups, C26 group showed a loss of subcutaneous fat and skeletal muscle confirming a cachectic phenotype in association with an elevation of serum IL-6 levels. Tumor-bearing mice groups show a tendecy towards to both LV systolic and diastolic dysfunction. Sarcomere dysfunction, including significantly reduced maximum calcium-activated tension (Tmax) and increased calcium sensitivity (decreased EC 50 ) was found in skinned cardiomyocyte preparation from both tumor-bearing mice in compared to controls (p&lt;0.05, respectively). Intracellular Ca 2+ transient was exclusively increased in CM isolated from cachectic mice, suggesting the SERCA2 upregulation. Infiltration of macrophage or T-cells, nor interstital fibrosis were difference. β-myosin heavy chain expression is upregulated in a cell autonomous fashion in C26 mice. Comprehensive energetic and metabolims analysis showed shift to a profound glucose metabolsim and reduction in fatty acid oxidation in LV samples. This was futher proven in h9c2 cells were incubated with C26 or shIL6 cell culture medium. Discussion: Our results suggest that LV dysfunction in cancer mice is associated with sarcomere dysfunction while additional abnormal intracellular Ca 2+ handling is solely present in mice with cachectic phenotype. These functional alterations are independent from changes in myocardial fibrosis and inflammation but may rely on the cardiac metabolism alterations. These data provide new insights into how cancer and cancer-cachexia impacts the cardiac performance even prior to cancer therapy treatments.

Abstract Or114: Inhibiting IL-1 Signaling to Cardiac Fibroblasts Protects Against Acute Viral Myocarditis

Background: Understanding what factors perpetuate cardiac inflammation in patients with unremitting inflammatory dilated cardiomyopathy (iDCM) is critical for developing curative therapies. We have previously demonstrated that inflammatory fibroblasts (IFs), a subset of cardiac fibroblasts (CFs) that promote inflammation, depend on IL-17A signaling to drive iDCM progression in experimental autoimmune myocarditis. Here, we demonstrate that IL-1 signaling more potently activates IFs than IL-17A. IL-1 signaling has been implicated in the pathogenesis of viral myocarditis, the most common etiology of myocarditis, though the mechanism is unclear. Hypothesis: We hypothesize that IL-1 signaling to CFs induces their differentiation into IFs, which drive pathogenic inflammation during viral myocarditis. Methods: Primary murine CF cultures were used to characterize IF activation by various cytokines. Next, we both performed qPCR on sorted CFs and used a CCL2-mCherry reporter mouse line to phenotype IF activation during Coxsackievirus B3 (CVB3) myocarditis. Finally, in-vivo fibroblast-specific IL-1 signaling was genetically ablated using PDGFRα cre IL1r1 fl/fl mice. We infected PDGFRα cre and PDGFRα cre IL1r1 fl/fl mice with CVB3 and assessed myocarditis severity during the peak of inflammation using histological scoring and flow cytometry. Results: Innate, Th1, Th2, and Th17 related cytokines such as IL-1β, IFNγ, IL-13, and IL-17A induced unique IF gene expression signatures. IL-1β most potently activated IFs with a pro-myeloid cytokine inflammatory profile. During CVB3 myocarditis, IF activation peaked on day 3 post infection and was sustained until day 10. Ablating IL-1 signaling to CFs reduced the magnitude of cardiac inflammation by 45% ± 14% (p=0.002) during the peak of CVB3 myocarditis with a reduction in monocyte, CD4+ T cells, CD8+ T cells, and NK cell recruitment. Gene expression analysis of sorted CFs from mutant and control mice revealed reduced expression of pro-myeloid chemokines such as CXCL1 and CCL2 on day 3 of CVB3 myocarditis. Conclusions: Cardiac fibroblasts exhibit remarkable plasticity allowing them to respond to a changing micro-environment. Blocking IL-1 signaling to IFs during CVB3 myocarditis inhibited production of pro-inflammatory chemokines resulting in attenuation of myocardial inflammation. Therefore, early IF activity acts as a rheostat to modulate the magnitude of cardiac inflammation during myocarditis.

Abstract We061: Cardiomyocytes HIPK2 Regulates Myocardial Inflammation And Heart Function Through Purinergic Signaling

Background: Homeodomain-interacting protein kinase 2 (HIPK2) is a serine/threonine kinase that belongs to an evolutionary conserved HIPK family of kinases. HIPK2-mediated regulation of the inflammation axis of signaling is a comparatively new concept. Purinergic signaling is critical to myocardial inflammation and function. However, there is no literature on HIPK2 regulating purinergic signaling. Methods and Results: Herein, we identified HIPK2, as a novel regulator of purinergic signaling. Cardiomyocyte-specific HIPK2 knockout (CM-HIPK2-KO) hearts exhibited reduced expression of multiple key players of canonical purinergic signaling, including ectonucleases CD39 and CD73, and led to excessive inflammation and cardiac dysfunction. Multiple in vitro experiments with gain-of-function (adenovirus expressing HIPK2, Ad-HIPK2), and loss-of-function (Ad-sh-RNA-HIPK2) approaches were performed to establish that HIPK2-mediated regulation of purinergic signaling is a conserved mechanism in many cell types of diverse backgrounds. Mechanistically, we identified that the signaling circuit of HIPK2-ERK-CREB exerts its effects on purinergic signaling through transcriptional control on CD39 and CD73. Aberrant activation of purinergic signaling and inflammation was critical to cardiac pathologies because interventions with purinergic signaling inhibitor apyrase or NLRP3 inflammasome inhibitor CY09 largely rescued the detrimental cardiac phenotype of CM-HIPK2 KOs. Conclusion: Herein, we identified HIPK2 as a novel regulator of purinergic signaling. Its deletion leads to excessive inflammation and cardiac dysfunction. Therefore, strategies to maintain HIPK2 are critical to sustaining cardiac health.

Abstract Mo124: New Rho-kinase Inhibitor Reduces Diastolic Dysfunction induced by Estrogen Depletion in Spontaneously Hypertensive Rats

Heart failure with preserved ejection fraction (HFpEF) observed in women with estrogen depletion is a consequence of the reduction of cardioprotection and endothelial dysfunction. Rho-kinase (ROCK) signaling pathway plays a role in cardiac dysfunction consequent to female aging. This work investigated the effects of a new synthetic ROCK inhibitor (iROCK) after oral administration in spontaneously hypertensive rats (SHR) submitted to oophorectomy (OVX). Experimental protocols were approved Animal Care and Use Committee at Universidade Federal do Rio de Janeiro. Under ketamine (80 mg/kg, i.p.) and xylazine (15 mg/kg, i.p.) anesthesia, female SHR submitted to OVX had cardiac function assessed after 8 weeks and compared to SHR-Sham. Eight weeks after OVX, SHR were randomly divided in groups, which were orally treated with either vehicle (DMSO) or iROCK (10 mg/kg) during 2 weeks. Novel iROCK displays potent inhibitory activity for ROCK1 and ROCK2 isoforms, with IC50 of 1.3 μM and 1.7 μM, respectively. At the end of treatment, hemodynamic parameters were evaluated using echocardiography and LV catheterization. Cardiac tissues collected for determining the expression of mitogen-activated protein kinases p38MAPK and extracellular signal-regulated kinase (ERK-1/2) using Western blot technique. After 8 weeks of estrogen depletion, SHR displayed HFpEF because ejection fraction (EF) was 85.2 ± 0.9%, while a reduction in EF from 83.0 ± 2.7 to 64.9 ± 0.9% was only detected after 12 weeks of OVX. Altered filling pressure confirmed the diastolic dysfunction after OVX, because the ratio of rapid mitral flow (E) to rapid wave of mitral annulus tissue Doppler (e') increased from 12.1 ± 1.3 in SHR-Sham to 19.3 ± 0.5. LV end diastolic pressure (LVEDP) increased from 13.4 ± 1.3 to 21.1 ± 4.9 in SHR after 8 weeks post-OVX. Oral administration of iROCK (10 mg/kg) reduced both E/e’ to 16.2 ± 0.5 and LVEDP to 6.4 ± 0.7 mmHg. OVX in SHR increased cardiac p38 MAPK and ERK-1/2 contents by 2.3 and 1.3 fold from SHR-Sham values. In contrast, iROCK reduced p38 overexpression but not altered ERK-1/2 content. Since pro-inflammatory cytokines and oxidative stress activate p38, the recovery of its expression after treatment, indicates that iROCK could reduce the inflammatory component of HF. In conclusion, the new iROCK recovered LV diastolic function induced by estrogen depletion in SHR, through the reduction of myocardial inflammation.

Echocardiographic Assessment of Cardiac Function and Reserve Under Exercise in Post–COVID-19 Children: A Prospective Cross-sectional Study

BackgroundCardiovascular impairment has been observed in adults with coronavirus disease 2019 (COVID-19), even in those with mild symptoms. Physical activity can reveal subtle cardiovascular dysfunction that is not apparent at rest. However, there are limited data on cardiovascular function in children and adolescents after the COVID-19 infection. This study aimed to assess cardiovascular function in paediatric and adolescent populations with a history of COVID-19 infection and controls by conducting 2-dimensional transthoracic echocardiography at rest (TTE-R) and exercise stress echocardiography (ESE). MethodsWe conducted TTE-R, including speckle tracking strain analysis of both ventricles, on 100 individuals (median age 12.3 years, 82% male), divided into 2 groups: 73 adolescents with COVID-19 infection and 27 controls. A subset of male participants (40 cases, 15 controls) underwent ESE combined with a cardiopulmonary exercise test (CPET-ESE) to examine the relationship between cardiovascular parameters and contractile reserve. Myocardial contractile reserve was evaluated by measuring the maximum increase in strain values during exercise. ResultsAt rest, no signs of myocardial injury or inflammation were observed. Right and left ventricular contractility in the infected group were clinically equivalent to those in the controls. During CPET-ESE, peak oxygen consumption was similar between the infected and control groups. Furthermore, contractile reserve under exercise was similar in both groups. ConclusionsWe found no significant differences in left ventricular systolic and diastolic function and right ventricle systolic function evaluated by TTE-R between participants with a history of mild COVID-19 infection and controls. ESE provided insights for post–COVID-19 young people resuming activities and sports.