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Miyoshi Y, Lucena-Cacace A, Tian Y, Matsumura Y, Tani K, Nishikawa M, Narita M, Kimura T, Ono K, Yoshida Y. SMAD3 mediates the specification of human induced pluripotent stem cell-derived epicardium into progenitors for the cardiac pericyte lineage. Stem Cell Reports 2024:S2213-6711(24)00246-7. [PMID: 39332407 DOI: 10.1016/j.stemcr.2024.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 08/23/2024] [Accepted: 08/26/2024] [Indexed: 09/29/2024] Open
Abstract
Understanding the molecular mechanisms of epicardial epithelial-to-mesenchymal transition (EMT), particularly in directing cell fate toward epicardial derivatives, is crucial for regenerative medicine using human induced pluripotent stem cell (iPSC)-derived epicardium. Although transforming growth factor β (TGF-β) plays a pivotal role in epicardial biology, orchestrating EMT during embryonic development via downstream signaling through SMAD proteins, the function of SMAD proteins in the epicardium in maintaining vascular homeostasis or mediating the differentiation of various epicardial-derived cells (EPDCs) is not yet well understood. Our study reveals that TGF-β-independent SMAD3 expression autonomously predicts epicardial cell specification and lineage maintenance, acting as a key mediator in promoting the angiogenic-oriented specification of the epicardium into cardiac pericyte progenitors. This finding uncovers a novel role for SMAD3 in the human epicardium, particularly in generating cardiac pericyte progenitors that enhance cardiac microvasculature angiogenesis. This insight opens new avenues for leveraging epicardial biology in developing more effective cardiac regeneration strategies.
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Ozgur SS, Elkattawy S, Shamoon Y, Ahmad A, Perez M, Abboud R, Shamoon F. A case image of epicardial implants in a young male with mixed germ cell tumor. Clin Case Rep 2024; 12:e9417. [PMID: 39229299 PMCID: PMC11369636 DOI: 10.1002/ccr3.9417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2024] [Revised: 07/08/2024] [Accepted: 07/29/2024] [Indexed: 09/05/2024] Open
Abstract
Epicardial metastasis from mixed germ cell tumors is exceedingly rare and poses a significant risk for cardiac morbidity. This case highlights the crucial need for comprehensive systemic evaluation in patients with known malignancies presenting with cardiac symptoms.
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Bannerman D, Gil de Gomez SP, Wu Q, Fernandes I, Zhao Y, Wagner KT, Okhovatian S, Landau S, Raftian N, Bodenstein DF, Wang Y, Nash TR, Vunjak-Novakovic G, Keller G, Epelman S, Radisic M. Heart-on-a-Chip Model of Epicardial-Myocardial Interaction in Ischemia Reperfusion Injury. Adv Healthc Mater 2024; 13:e2302642. [PMID: 38683053 PMCID: PMC11338737 DOI: 10.1002/adhm.202302642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 03/22/2024] [Indexed: 05/01/2024]
Abstract
Epicardial cells (EPIs) form the outer layer of the heart and play an important role in development and disease. Current heart-on-a-chip platforms still do not fully mimic the native cardiac environment due to the absence of relevant cell types, such as EPIs. Here, using the Biowire II platform, engineered cardiac tissues with an epicardial outer layer and inner myocardial structure are constructed, and an image analysis approach is developed to track the EPI cell migration in a beating myocardial environment. Functional properties of EPI cardiac tissues improve over two weeks in culture. In conditions mimicking ischemia reperfusion injury (IRI), the EPI cardiac tissues experience less cell death and a lower impact on functional properties. EPI cell coverage is significantly reduced and more diffuse under normoxic conditions compared to the post-IRI conditions. Upon IRI, migration of EPI cells into the cardiac tissue interior is observed, with contributions to alpha smooth muscle actin positive cell population. Altogether, a novel heart-on-a-chip model is designed to incorporate EPIs through a formation process that mimics cardiac development, and this work demonstrates that EPI cardiac tissues respond to injury differently than epicardium-free controls, highlighting the importance of including EPIs in heart-on-a-chip constructs that aim to accurately mimic the cardiac environment.
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Butler K, Ahmed S, Jablonski J, Hookway TA. Engineered Cardiac Microtissue Biomanufacturing Using Human Induced Pluripotent Stem Cell Derived Epicardial Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593960. [PMID: 38798424 PMCID: PMC11118268 DOI: 10.1101/2024.05.13.593960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Epicardial cells are a crucial component in constructing in vitro 3D tissue models of the human heart, contributing to the ECM environment and the resident mesenchymal cell population. Studying the human epicardium and its development from the proepicardial organ is difficult, but induced pluripotent stem cells can provide a source of human epicardial cells for developmental modeling and for biomanufacturing heterotypic cardiac tissues. This study shows that a robust population of epicardial cells (approx. 87.7% WT1+) can be obtained by small molecule modulation of the Wnt signaling pathway. The population maintains WT1 expression and characteristic epithelial morphology over successive passaging, but increases in size and decreases in cell number, suggesting a limit to their expandability in vitro. Further, low passage number epicardial cells formed into more robust 3D microtissues compared to their higher passage counterparts, suggesting that the ideal time frame for use of these epicardial cells for tissue engineering and modeling purposes is early on in their differentiated state. Additionally, the differentiated epicardial cells displayed two distinct morphologic sub populations with a subset of larger, more migratory cells which led expansion of the epicardial cells across various extracellular matrix environments. When incorporated into a mixed 3D co-culture with cardiomyocytes, epicardial cells promoted greater remodeling and migration without impairing cardiomyocyte function. This study provides an important characterization of stem cell-derived epicardial cells, identifying key characteristics that influence their ability to fabricate consistent engineered cardiac tissues.
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Sun J, Peterson EA, Chen X, Wang J. ptx3a + fibroblast/epicardial cells provide a transient macrophage niche to promote heart regeneration. Cell Rep 2024; 43:114092. [PMID: 38607913 PMCID: PMC11092985 DOI: 10.1016/j.celrep.2024.114092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/28/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Macrophages conduct critical roles in heart repair, but the niche required to nurture and anchor them is poorly studied. Here, we investigated the macrophage niche in the regenerating heart. We analyzed cell-cell interactions through published single-cell RNA sequencing datasets and identified a strong interaction between fibroblast/epicardial (Fb/Epi) cells and macrophages. We further visualized the association of macrophages with Fb/Epi cells and the blockage of macrophage response without Fb/Epi cells in the regenerating zebrafish heart. Moreover, we found that ptx3a+ epicardial cells associate with reparative macrophages, and their depletion resulted in fewer reparative macrophages. Further, we identified csf1a expression in ptx3a+ cells and determined that pharmacological inhibition of the csf1a pathway or csf1a knockout blocked the reparative macrophage response. Moreover, we found that genetic overexpression of csf1a enhanced the reparative macrophage response with or without heart injury. Altogether, our studies illuminate a cardiac Fb/Epi niche, which mediates a beneficial macrophage response after heart injury.
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Paquette SE, Oduor CI, Gaulke A, Stefan S, Bronk P, Dafonseca V, Barulin N, Lee C, Carley R, Morrison AR, Choi BR, Bailey JA, Plavicki JS. Loss of developmentally derived Irf8+ macrophages promotes hyperinnervation and arrhythmia in the adult zebrafish heart. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.589909. [PMID: 38659956 PMCID: PMC11042273 DOI: 10.1101/2024.04.17.589909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Recent developments in cardiac macrophage biology have broadened our understanding of the critical functions of macrophages in the heart. As a result, there is further interest in understanding the independent contributions of distinct subsets of macrophage to cardiac development and function. Here, we demonstrate that genetic loss of interferon regulatory factor 8 (Irf8)-positive embryonic-derived macrophages significantly disrupts cardiac conduction, chamber function, and innervation in adult zebrafish. At 4 months post-fertilization (mpf), homozygous irf8st96/st96 mutants have significantly shortened atrial action potential duration and significant differential expression of genes involved in cardiac contraction. Functional in vivo assessments via electro- and echocardiograms at 12 mpf reveal that irf8 mutants are arrhythmogenic and exhibit diastolic dysfunction and ventricular stiffening. To identify the molecular drivers of the functional disturbances in irf8 null zebrafish, we perform single cell RNA sequencing and immunohistochemistry, which reveal increased leukocyte infiltration, epicardial activation, mesenchymal gene expression, and fibrosis. Irf8 null hearts are also hyperinnervated and have aberrant axonal patterning, a phenotype not previously assessed in the context of cardiac macrophage loss. Gene ontology analysis supports a novel role for activated epicardial-derived cells (EPDCs) in promoting neurogenesis and neuronal remodeling in vivo. Together, these data uncover significant cardiac abnormalities following embryonic macrophage loss and expand our knowledge of critical macrophage functions in heart physiology and governing homeostatic heart health.
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Nguyen DSN, Lin CY, Chung FP, Chang TY, Lo LW, Lin YJ, Chang SL, Hu YF, Tuan TC, Chao TF, Liao JN, Kuo L, Liu CM, Liu SH, Wu CI, Kuo MJ, Li GY, Huang YS, Wu SJ, Siow YK, Bautista JAL, Cao DT, Chen SA. Signal-averaged electrocardiography as a noninvasive tool for evaluating the ventricular substrate in patients with nonischemic cardiomyopathy: reassessment of an old tool. Front Cardiovasc Med 2024; 11:1306055. [PMID: 38689859 PMCID: PMC11058987 DOI: 10.3389/fcvm.2024.1306055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 04/03/2024] [Indexed: 05/02/2024] Open
Abstract
Introduction Signal-averaged electrocardiography (SAECG) provides diagnostic and prognostic information regarding cardiac diseases. However, its value in other nonischemic cardiomyopathies (NICMs) remains unclear. This study aimed to investigate the role of SAECG in patients with NICM. Methods and results This retrospective study included consecutive patients with NICM who underwent SAECG, biventricular substrate mapping, and ablation for ventricular arrhythmia (VA). Patients with baseline ventricular conduction disturbances were excluded. Patients who fulfilled at least one SAECG criterion were categorized into Group 1, and the other patients were categorized into Group 2. Baseline and ventricular substrate characteristics were compared between the two groups. The study included 58 patients (39 men, mean age 50.4 ± 15.5 years), with 34 and 24 patients in Groups 1 and 2, respectively. Epicardial mapping was performed in eight (23.5%) and six patients (25.0%) in Groups 1 and 2 (p = 0.897), respectively. Patients in Group 1 had a more extensive right ventricular (RV) low-voltage zone (LVZ) and scar area than those in Group 2. Group 1 had a larger epicardial LVZ than Group 2. Epicardial late potentials were more frequent in Group 1 than in Group 2. There were more arrhythmogenic foci within the RV outflow tract in Group 1 than in Group 2. There was no significant difference in long-term VA recurrence. Conclusion In our NICM population, a positive SAECG was associated with a larger RV endocardial scar, epicardial scar/late potentials, and a higher incidence of arrhythmogenic foci in the RV outflow tract.
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Weinberger M, Simões FC, Gungoosingh T, Sauka-Spengler T, Riley PR. Distinct epicardial gene regulatory programs drive development and regeneration of the zebrafish heart. Dev Cell 2024; 59:351-367.e6. [PMID: 38237592 DOI: 10.1016/j.devcel.2023.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/12/2023] [Accepted: 12/20/2023] [Indexed: 02/08/2024]
Abstract
Unlike the adult mammalian heart, which has limited regenerative capacity, the zebrafish heart fully regenerates following injury. Reactivation of cardiac developmental programs is considered key to successfully regenerating the heart, yet the regulation underlying the response to injury remains elusive. Here, we compared the transcriptome and epigenome of the developing and regenerating zebrafish epicardia. We identified epicardial enhancer elements with specific activity during development or during adult heart regeneration. By generating gene regulatory networks associated with epicardial development and regeneration, we inferred genetic programs driving each of these processes, which were largely distinct. Loss of Hif1ab, Nrf1, Tbx2b, and Zbtb7a, central regulators of the regenerating epicardial network, in injured hearts resulted in elevated epicardial cell numbers infiltrating the wound and excess fibrosis after cryoinjury. Our work identifies differences between the regulatory blueprint deployed during epicardial development and regeneration, underlining that heart regeneration goes beyond the reactivation of developmental programs.
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Kahn ML. CCM Function in the Heart: Working From Outside-In Rather Than Inside-Out. JACC Basic Transl Sci 2024; 9:220-222. [PMID: 38510721 PMCID: PMC10950394 DOI: 10.1016/j.jacbts.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
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Wang R, Lu D, Song R, Du L, Yang X, Wu ST, Wang X, Wong J, Xu Z, Zhao Q, Liu R, Zheng X. Epicardial CCM2 Promotes Cardiac Development and Repair Via its Regulation on Cytoskeletal Reorganization. JACC Basic Transl Sci 2024; 9:203-219. [PMID: 38510716 PMCID: PMC10950406 DOI: 10.1016/j.jacbts.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 03/22/2024]
Abstract
The epicardium provides epicardial-derived cells and molecular signals to support cardiac development and regeneration. Zebrafish and mouse studies have shown that ccm2, a cerebral cavernous malformation disease gene, is essential for cardiac development. Endocardial cell-specific deletion of Ccm2 in mice has previously established that Ccm2 is essential for maintenance of the cardiac jelly for cardiac development during early gestation. The current study aimed to explore the function of Ccm2 in epicardial cells for heart development and regeneration. Through genetic deletion of Ccm2 in epicardial cells, our in vivo and ex vivo experiments revealed that Ccm2 is required by epicardial cells to support heart development. Ccm2 regulates epicardial cell adhesion, cell polarity, cell spreading, and migration. Importantly, the loss of Ccm2 in epicardial cells delays cardiac function recovery and aggravates cardiac fibrosis following myocardial infarction. Molecularly, Ccm2 targets the production of cytoskeletal and matrix proteins to maintain epicardial cell function and behaviors. Epicardial Ccm2 plays a critical role in heart development and regeneration via its regulation of cytoskeleton reorganization.
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Carmona R, López-Sánchez C, Garcia-Martinez V, Garcia-López V, Muñoz-Chápuli R, Lozano-Velasco E, Franco D. Novel Insights into the Molecular Mechanisms Governing Embryonic Epicardium Formation. J Cardiovasc Dev Dis 2023; 10:440. [PMID: 37998498 PMCID: PMC10672416 DOI: 10.3390/jcdd10110440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/20/2023] [Accepted: 10/22/2023] [Indexed: 11/25/2023] Open
Abstract
The embryonic epicardium originates from the proepicardium, an extracardiac primordium constituted by a cluster of mesothelial cells. In early embryos, the embryonic epicardium is characterized by a squamous cell epithelium resting on the myocardium surface. Subsequently, it invades the subepicardial space and thereafter the embryonic myocardium by means of an epithelial-mesenchymal transition. Within the myocardium, epicardial-derived cells present multilineage potential, later differentiating into smooth muscle cells and contributing both to coronary vasculature and cardiac fibroblasts in the mature heart. Over the last decades, we have progressively increased our understanding of those cellular and molecular mechanisms driving proepicardial/embryonic epicardium formation. This study provides a state-of-the-art review of the transcriptional and emerging post-transcriptional mechanisms involved in the formation and differentiation of the embryonic epicardium.
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Yamaoka K, Arai T, Takahashi M, Hojo R, Fukamizu S. Bidirectional rotating biatrial tachycardia. J Arrhythm 2023; 39:830-833. [PMID: 37799785 PMCID: PMC10549809 DOI: 10.1002/joa3.12919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/28/2023] [Accepted: 08/15/2023] [Indexed: 10/07/2023] Open
Abstract
A 72-year-old man was treated for recurrent atrial tachycardia (AT) and underwent ablation. The AT was diagnosed as bi-AT based on the activation map and the postpacing interval. Another AT appeared and was diagnosed as bi-AT by the same method. Surprisingly, the circuits of both ATs were perfectly matched and rotated in opposite directions. The left atrial anteroseptal wall was ablated during the AT. The AT was immediately stopped and was no longer induced.
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Sanchez-Fernandez C, Rodriguez-Outeiriño L, Matias-Valiente L, Ramírez de Acuña F, Franco D, Aránega AE. Understanding Epicardial Cell Heterogeneity during Cardiogenesis and Heart Regeneration. J Cardiovasc Dev Dis 2023; 10:376. [PMID: 37754805 PMCID: PMC10531887 DOI: 10.3390/jcdd10090376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/28/2023] Open
Abstract
The outermost layer of the heart, the epicardium, is an essential cell population that contributes, through epithelial-to-mesenchymal transition (EMT), to the formation of different cell types and provides paracrine signals to the developing heart. Despite its quiescent state during adulthood, the adult epicardium reactivates and recapitulates many aspects of embryonic cardiogenesis in response to cardiac injury, thereby supporting cardiac tissue remodeling. Thus, the epicardium has been considered a crucial source of cell progenitors that offers an important contribution to cardiac development and injured hearts. Although several studies have provided evidence regarding cell fate determination in the epicardium, to date, it is unclear whether epicardium-derived cells (EPDCs) come from specific, and predetermined, epicardial cell subpopulations or if they are derived from a common progenitor. In recent years, different approaches have been used to study cell heterogeneity within the epicardial layer using different experimental models. However, the data generated are still insufficient with respect to revealing the complexity of this epithelial layer. In this review, we summarize the previous works documenting the cellular composition, molecular signatures, and diversity within the developing and adult epicardium.
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Ong LP, Bargehr J, Knight-Schrijver VR, Lee J, Colzani M, Bayraktar S, Bernard WG, Marchiano S, Bertero A, Murry CE, Gambardella L, Sinha S. Epicardially secreted fibronectin drives cardiomyocyte maturation in 3D-engineered heart tissues. Stem Cell Reports 2023; 18:936-951. [PMID: 37001515 PMCID: PMC10147941 DOI: 10.1016/j.stemcr.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 04/14/2023] Open
Abstract
Ischemic heart failure is due to irreversible loss of cardiomyocytes. Preclinical studies showed that human pluripotent stem cell (hPSC)-derived cardiomyocytes could remuscularize infarcted hearts and improve cardiac function. However, these cardiomyocytes remained immature. Incorporating hPSC-derived epicardial cells has been shown to improve cardiomyocyte maturation, but the exact mechanisms are unknown. We posited epicardial fibronectin (FN1) as a mediator of epicardial-cardiomyocyte crosstalk and assessed its role in driving hPSC-derived cardiomyocyte maturation in 3D-engineered heart tissues (3D-EHTs). We found that the loss of FN1 with peptide inhibition F(pUR4), CRISPR-Cas9-mediated FN1 knockout, or tetracycline-inducible FN1 knockdown in 3D-EHTs resulted in immature cardiomyocytes with decreased contractile function, and inefficient Ca2+ handling. Conversely, when we supplemented 3D-EHTs with recombinant human FN1, we could recover hPSC-derived cardiomyocyte maturation. Finally, our RNA-sequencing analyses found FN1 within a wider paracrine network of epicardial-cardiomyocyte crosstalk, thus solidifying FN1 as a key driver of hPSC-derived cardiomyocyte maturation in 3D-EHTs.
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Pappone C, Ciconte G, Anastasia L, Gaita F, Grant E, Micaglio E, Locati ET, Calovic Z, Vicedomini G, Santinelli V. Right ventricular epicardial arrhythmogenic substrate in long-QT syndrome patients at risk of sudden death. Europace 2023; 25:948-955. [PMID: 36610790 PMCID: PMC10062343 DOI: 10.1093/europace/euac264] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/16/2022] [Indexed: 01/09/2023] Open
Abstract
AIMS The long-QT syndrome (LQTS) represents a leading cause of sudden cardiac death (SCD). The aim of this study was to assess the presence of an underlying electroanatomical arrhythmogenic substrate in high-risk LQTS patients. METHODS AND RESULTS The present study enrolled 11 consecutive LQTS patients who had experienced frequent implantable cardioverter-defibrillator (ICD discharges triggered by ventricular fibrillation (VF). We acquired electroanatomical biventricular maps of both endo and epicardial regions for all patients and analyzed electrograms sampled from several myocardial regions. Abnormal electrical activities were targeted and eliminated by the means of radiofrequency catheter ablation. VF episodes caused a median of four ICD discharges in eleven patients (6 male, 54.5%; mean age 44.0 ± 7.8 years, range 22-53) prior to our mapping and ablation procedures. The average QTc interval was 500.0 ± 30.2 ms. Endo-epicardial biventricular maps displayed abnormally fragmented, low-voltage (0.9 ± 0.2 mV) and prolonged electrograms (89.9 ± 24.1 ms) exclusively localized in the right ventricular epicardium. We found electrical abnormalities extending over a mean epicardial area of 15.7 ± 3.1 cm2. Catheter ablation of the abnormal epicardial area completely suppressed malignant arrhythmias over a mean 12 months of follow-up (median VF episodes before vs. after ablation, 4 vs. 0; P = 0.003). After the procedure, the QTc interval measured in a 12-lead ECG analysis shortened to a mean of 461.8 ± 23.6 ms (P = 0.004). CONCLUSION This study reveals that, among high-risk LQTS patients, regions localized in the epicardium of the right ventricle harbour structural electrophysiological abnormalities. Elimination of these abnormal electrical activities successfully prevented malignant ventricular arrhythmia recurrences.
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Huang YM, Hsieh CH, Wang SY, Tsao CH, Lee JC, Chen YJ. Treatment Resulting Changes in Volumes of High- 18F-FDG-Uptake Adipose Tissues over Orbit and Epicardium Correlate with Treatment Response for Non-Hodgkin's Lymphoma. Int J Mol Sci 2023; 24:ijms24032158. [PMID: 36768479 PMCID: PMC9916748 DOI: 10.3390/ijms24032158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND A regimen of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard treatment for non-Hodgkin's lymphoma. Brown adipose tissue possesses anti-cancer potential. This study aimed to explore practical biomarkers for non-Hodgkin's lymphoma by analyzing the metabolic activity of adipose tissue. METHODS Twenty patients who received R-CHOP for non-Hodgkin's lymphoma were reviewed. Positron emission tomography/computed tomography (PET/CT) images, lactate dehydrogenase (LDH) levels, and body mass index (BMI) before and after treatment were collected. Regions with a high standardized uptake value (SUV) in epicardial and orbital adipose tissue were selected and analyzed by a PET/CT viewer. The initial measurements and changes in the high SUV of epicardial and orbital adipose tissues, LDH levels, and BMI of treatment responders and non-responders, and complete and partial responders, were compared. RESULTS The volumes of high-SUV epicardial and orbital adipose tissues significantly increased in responders after R-CHOP (p = 0.03 and 0.002, respectively). There were significant differences between changes in the high-SUV volumes of epicardial and orbital adipose tissues (p = 0.03 and 0.001, respectively) and LDH levels (p = 0.03) between responders and non-responders. The changes in high-SUV epicardial adipose tissue volumes were greater among complete responders than partial responders (p = 0.04). Poorer treatment responses were observed in patients with lower high-SUV epicardial adipose tissue volumes and higher LDH levels after R-CHOP (p = 0.03 and 0.03, respectively). CONCLUSIONS The preliminary results of greater changes in high-SUV epicardial and orbital adipose tissue volumes among responders indicate that brown adipose tissue could be considered a favorable prognostic biomarker.
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Maselli D, Matos RS, Johnson RD, Martella D, Caprettini V, Chiappini C, Camelliti P, Campagnolo P. Porcine Organotypic Epicardial Slice Protocol: A Tool for the Study of Epicardium in Cardiovascular Research. Front Cardiovasc Med 2022; 9:920013. [PMID: 35924218 PMCID: PMC9339655 DOI: 10.3389/fcvm.2022.920013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
The epicardium has recently gained interest in the cardiovascular field due to its capacity to support heart regeneration after ischemic injury. Models to study the epicardium of large animals in vitro are limited and mainly based on epicardial cell isolation/differentiation from stem cells, followed by 2D cells culture. In this method paper, we describe the procedure to obtain and culture 3D organotypic heart slices presenting an intact epicardium, as a novel model to study the epicardial physiology and activation. Epicardial slices are obtained from porcine hearts using a high-precision vibratome and retain a healthy epicardial layer embedded in its native extracellular environment and connected with other cardiac cells (cardiomyocytes, fibroblasts, vascular cells etc.). Epicardial slices can be cultured for 72 h, providing an ideal model for studying the epicardium physiology or perform pharmacological interventions/gene therapy approaches. We also report on methods to assesses the viability and composition of the epicardial slices, and evaluate their architecture in 3D through tissue decoloration. Finally, we present a potential application for a nanomaterial-based gene transfer method for tracking of epicardial cells within the slice. Crucially, given the similarity in morphology and physiology of porcine heart with its human counterpart, our system provides a platform for translational research while providing a clinically relevant and ethical alternative to the use of small animals in this type of research.
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Sun J, Peterson EA, Wang AZ, Ou J, Smith KE, Poss KD, Wang J. hapln1 Defines an Epicardial Cell Subpopulation Required for Cardiomyocyte Expansion During Heart Morphogenesis and Regeneration. Circulation 2022; 146:48-63. [PMID: 35652354 PMCID: PMC9308751 DOI: 10.1161/circulationaha.121.055468] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Certain nonmammalian species such as zebrafish have an elevated capacity for innate heart regeneration. Understanding how heart regeneration occurs in these contexts can help illuminate cellular and molecular events that can be targets for heart failure prevention or treatment. The epicardium, a mesothelial tissue layer that encompasses the heart, is a dynamic structure that is essential for cardiac regeneration in zebrafish. The extent to which different cell subpopulations or states facilitate heart regeneration requires research attention. METHODS To dissect epicardial cell states and associated proregenerative functions, we performed single-cell RNA sequencing and identified 7 epicardial cell clusters in adult zebrafish, 3 of which displayed enhanced cell numbers during regeneration. We identified paralogs of hapln1 as factors associated with the extracellular matrix and largely expressed in cluster 1. We assessed HAPLN1 expression in published single-cell RNA sequencing data sets from different stages and injury states of murine and human hearts, and we performed molecular genetics to determine the requirements for hapln1-expressing cells and functions of each hapln1 paralog. RESULTS A particular cluster of epicardial cells had the strongest association with regeneration and was marked by expression of hapln1a and hapln1b. The hapln1 paralogs are expressed in epicardial cells that enclose dedifferentiated and proliferating cardiomyocytes during regeneration. Induced genetic depletion of hapln1-expressing cells or genetic inactivation of hapln1b altered deposition of the key extracellular matrix component hyaluronic acid, disrupted cardiomyocyte proliferation, and inhibited heart regeneration. We also found that hapln1-expressing epicardial cells first emerge at the juvenile stage, when they associate with and are required for focused cardiomyocyte expansion events that direct maturation of the ventricular wall. CONCLUSIONS Our findings identify a subset of epicardial cells that emerge in postembryonic zebrafish and sponsor regions of active cardiomyogenesis during cardiac growth and regeneration. We provide evidence that, as the heart achieves its mature structure, these cells facilitate hyaluronic acid deposition to support formation of the compact muscle layer of the ventricle. They are also required, along with the function of hapln1b paralog, in the production and organization of hyaluronic acid-containing matrix in cardiac injury sites, enabling normal cardiomyocyte proliferation and muscle regeneration.
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Bruton FA, Kaveh A, Ross-Stewart KM, Matrone G, Oremek MEM, Solomonidis EG, Tucker CS, Mullins JJ, Lucas CD, Brittan M, Taylor JM, Rossi AG, Denvir MA. Macrophages trigger cardiomyocyte proliferation by increasing epicardial vegfaa expression during larval zebrafish heart regeneration. Dev Cell 2022; 57:1512-1528.e5. [PMID: 35688158 PMCID: PMC9616726 DOI: 10.1016/j.devcel.2022.05.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/11/2022] [Accepted: 05/18/2022] [Indexed: 12/01/2022]
Abstract
Cardiac injury leads to the loss of cardiomyocytes, which are rapidly replaced by the proliferation of the surviving cells in zebrafish, but not in mammals. In both the regenerative zebrafish and non-regenerative mammals, cardiac injury induces a sustained macrophage response. Macrophages are required for cardiomyocyte proliferation during zebrafish cardiac regeneration, but the mechanisms whereby macrophages facilitate this crucial process are fundamentally unknown. Using heartbeat-synchronized live imaging, RNA sequencing, and macrophage-null genotypes in the larval zebrafish cardiac injury model, we characterize macrophage function and reveal that these cells activate the epicardium, inducing cardiomyocyte proliferation. Mechanistically, macrophages are specifically recruited to the epicardial-myocardial niche, triggering the expansion of the epicardium, which upregulates vegfaa expression to induce cardiomyocyte proliferation. Our data suggest that epicardial Vegfaa augments a developmental cardiac growth pathway via increased endocardial notch signaling. The identification of this macrophage-dependent mechanism of cardiac regeneration highlights immunomodulation as a potential strategy for enhancing mammalian cardiac repair. Heart regeneration in larval zebrafish is characterized in detail Macrophage ablation blocks cardiomyocyte proliferation after cardiac injury Macrophages synapse with epicardial cells and promote their proliferation Epicardial Vegfaa drives cardiomyocyte proliferation during cardiac regeneration
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20
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Wang S, Yang G, Ju W, Sun X, Chen H, Chen M. Catheter ablation of atrial tachycardia originated from the left atrial epicardium. Pacing Clin Electrophysiol 2022; 45:1303-1305. [PMID: 35713398 DOI: 10.1111/pace.14553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/26/2022] [Accepted: 06/12/2022] [Indexed: 11/30/2022]
Abstract
A patient was referred with frequent atrial tachycardia attacks. Activation mapping showed that the LA roof was earlier activated with a broad region, and right atrial activation was delayed. The far-field A wave corresponding to the pulmonary artery area was advanced with failed ablation. Therefore, the atrial tachycardia could be left atrial epicardial origin, which was further confirmed by the successful ablation at earliest activated site at the epicardium. This article is protected by copyright. All rights reserved.
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Jum'ah H, Kundrapu S, Jabri A, Kondapaneni M, Tomashefski JF, Loeffler AG. Cardiac Macrophage Density in Covid-19 Infection: Relationship to Myocyte Necrosis and Acute Lung Injury. Cardiovasc Pathol 2022; 60:107447. [PMID: 35718082 PMCID: PMC9212794 DOI: 10.1016/j.carpath.2022.107447] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/27/2022] [Accepted: 06/12/2022] [Indexed: 11/30/2022] Open
Abstract
SARS-Cov-2 infection is not limited to the respiratory tract and can involve other organs including the heart, blood vessels, kidneys, liver, gastrointestinal tract, placenta, and skin. Covid-19 patients with cardiac involvement usually have higher morbidity and mortality compared to those without cardiac involvement. The frequency and the specificity of the myocardial pathological changes in patients who die after documented infection with SARS-Cov-2 is uncertain. Macrophages can be found in the normal heart (interstitium, around the endothelial cells and in the epicardial adipose tissue), and they are considered part of the major immune cell population in the heart. In this case-control autopsy study, we compare the gross and microscopic cardiac findings, and the available clinical characteristics between a group of 10 Covid-19 decedents and a control group of 20 patients who died with non-SARS-Cov-2 severe bronchopneumonia and/or diffuse alveolar damage. The objectives of this semi-quantitative study are to study single myocyte necrosis and its relation to the strain on the heart caused by lung injury as a causative mechanism, and to study the density of myocardial and epicardial macrophages in Covid-19 hearts in comparison to the control group, and in Covid-19 hearts with single myocyte necrosis in comparison to Covid-19 hearts without single myocyte necrosis. Lymphocytic myocarditis was not identified in any of the hearts from the Covid-19 or the control group. Single myocyte necrosis is more frequent in the Covid-19 group compared to the control group, suggesting that it is unrelated to the strain on the heart caused by underlying lung injury. The density of the macrophages in the epicardium and myocardium in the hearts of the Covid-19 group is higher compared to those in the control group. The density of epicardial macrophages is higher in the Covid-19 hearts with single myocyte necrosis than in those without. These observations contribute to our increasing appreciation of the role of macrophages in the pathophysiologic response to infection by SARS-CoV-2.
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Palmquist-Gomes P, Marín-Sedeño E, Ruiz-Villalba A, Rico-Llanos GA, Pérez-Pomares JM, Guadix JA. In Vivo and In Vitro Cartilage Differentiation from Embryonic Epicardial Progenitor Cells. Int J Mol Sci 2022; 23:ijms23073614. [PMID: 35408974 PMCID: PMC8999123 DOI: 10.3390/ijms23073614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
The presence of cartilage tissue in the embryonic and adult hearts of different vertebrate species is a well-recorded fact. However, while the embryonic neural crest has been historically considered as the main source of cardiac cartilage, recently reported results on the wide connective potential of epicardial lineage cells suggest they could also differentiate into chondrocytes. In this work, we describe the formation of cardiac cartilage clusters from proepicardial cells, both in vivo and in vitro. Our findings report, for the first time, cartilage formation from epicardial progenitor cells, and strongly support the concept of proepicardial cells as multipotent connective progenitors. These results are relevant to our understanding of cardiac cell complexity and the responses of cardiac connective tissues to pathologic stimuli.
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Regulation of Epicardial Cell Fate during Cardiac Development and Disease: An Overview. Int J Mol Sci 2022; 23:ijms23063220. [PMID: 35328640 PMCID: PMC8950551 DOI: 10.3390/ijms23063220] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 01/27/2023] Open
Abstract
The epicardium is the outermost cell layer in the vertebrate heart that originates during development from mesothelial precursors located in the proepicardium and septum transversum. The epicardial layer plays a key role during cardiogenesis since a subset of epicardial-derived cells (EPDCs) undergo an epithelial–mesenchymal transition (EMT); migrate into the myocardium; and differentiate into distinct cell types, such as coronary vascular smooth muscle cells, cardiac fibroblasts, endothelial cells, and presumably a subpopulation of cardiomyocytes, thus contributing to complete heart formation. Furthermore, the epicardium is a source of paracrine factors that support cardiac growth at the last stages of cardiogenesis. Although several lineage trace studies have provided some evidence about epicardial cell fate determination, the molecular mechanisms underlying epicardial cell heterogeneity remain not fully understood. Interestingly, seminal works during the last decade have pointed out that the adult epicardium is reactivated after heart damage, re-expressing some embryonic genes and contributing to cardiac remodeling. Therefore, the epicardium has been proposed as a potential target in the treatment of cardiovascular disease. In this review, we summarize the previous knowledge regarding the regulation of epicardial cell contribution during development and the control of epicardial reactivation in cardiac repair after damage.
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Guo Z, Geng M, Qin L, Hao B, Liao S. Epicardium-Derived Tbx18 + CDCs Transplantation Improve Heart Function in Infarcted Mice. Front Cardiovasc Med 2022; 8:744353. [PMID: 35141286 PMCID: PMC8820322 DOI: 10.3389/fcvm.2021.744353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Cardiosphere-derived cells (CDCs) constitute a cardiac stem cell pool, a promising therapeutics in treating myocardial infarction (MI). However, the cell source of CDCs remains unclear. In this study, we isolated CDCs directly from adult mouse heart epicardium named primary epicardium-derived CDCs (pECDCs), which showed a different expression profile compared with primary epicardial cells (pEpiCs). Interestingly, pECDCs highly expressed T-box transcription factor 18 (Tbx18) and showed multipotent differentiation ability in vitro. Human telomerase reverse transcriptase (hTERT) transduction could inhibit aging-induced pECDCs apoptosis and differentiation, thus keeping a better proliferation capacity. Furthermore, immortalized epicardium CDCs (iECDCs) transplantation extensively promote cardiogenesis in the infracted mouse heart. This study demonstrated epicardium-derived CDCs that may derive from Tbx18+ EpiCs, which possess the therapeutic potential to be applied to cardiac repair and regeneration and suggest a new kind of CDCs with identified origination that may be followed in the developing and injured heart.
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Wasserman AH, Huang AR, Lewis-Israeli YR, Dooley MD, Mitchell AL, Venkatesan M, Aguirre A. Oxytocin promotes epicardial cell activation and heart regeneration after cardiac injury. Front Cell Dev Biol 2022; 10:985298. [PMID: 36247002 PMCID: PMC9561106 DOI: 10.3389/fcell.2022.985298] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
Cardiovascular disease (CVD) is one of the leading causes of mortality worldwide, and frequently leads to massive heart injury and the loss of billions of cardiac muscle cells and associated vasculature. Critical work in the last 2 decades demonstrated that these lost cells can be partially regenerated by the epicardium, the outermost mesothelial layer of the heart, in a process that highly recapitulates its role in heart development. Upon cardiac injury, mature epicardial cells activate and undergo an epithelial-mesenchymal transition (EMT) to form epicardium-derived progenitor cells (EpiPCs), multipotent progenitors that can differentiate into several important cardiac lineages, including cardiomyocytes and vascular cells. In mammals, this process alone is insufficient for significant regeneration, but it might be possible to prime it by administering specific reprogramming factors, leading to enhanced EpiPC function. Here, we show that oxytocin (OXT), a hypothalamic neuroendocrine peptide, induces epicardial cell proliferation, EMT, and transcriptional activity in a model of human induced pluripotent stem cell (hiPSC)-derived epicardial cells. In addition, we demonstrate that OXT is produced after cardiac cryoinjury in zebrafish, and that it elicits significant epicardial activation promoting heart regeneration. Oxytocin signaling is also critical for proper epicardium development in zebrafish embryos. The above processes are significantly impaired when OXT signaling is inhibited chemically or genetically through RNA interference. RNA sequencing data suggests that the transforming growth factor beta (TGF-β) pathway is the primary mediator of OXT-induced epicardial activation. Our research reveals for the first time an evolutionary conserved brain-controlled mechanism inducing cellular reprogramming and regeneration of the injured mammalian and zebrafish heart, a finding that could contribute to translational advances for the treatment of cardiac injuries.
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