1
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Kyriakopoulou E, Versteeg D, de Ruiter H, Perini I, Seibertz F, Döring Y, Zentilin L, Tsui H, van Kampen SJ, Tiburcy M, Meyer T, Voigt N, Tintelen VJP, Zimmermann WH, Giacca M, van Rooij E. Therapeutic efficacy of AAV-mediated restoration of PKP2 in arrhythmogenic cardiomyopathy. NATURE CARDIOVASCULAR RESEARCH 2023; 2:1262-1276. [PMID: 38665939 PMCID: PMC11041734 DOI: 10.1038/s44161-023-00378-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/27/2023] [Indexed: 04/28/2024]
Abstract
Arrhythmogenic cardiomyopathy is a severe cardiac disorder characterized by lethal arrhythmias and sudden cardiac death, with currently no effective treatment. Plakophilin 2 (PKP2) is the most frequently affected gene. Here we show that adeno-associated virus (AAV)-mediated delivery of PKP2 in PKP2c.2013delC/WT induced pluripotent stem cell-derived cardiomyocytes restored not only cardiac PKP2 levels but also the levels of other junctional proteins, found to be decreased in response to the mutation. PKP2 restoration improved sodium conduction, indicating rescue of the arrhythmic substrate in PKP2 mutant induced pluripotent stem cell-derived cardiomyocytes. Additionally, it enhanced contractile function and normalized contraction kinetics in PKP2 mutant engineered human myocardium. Recovery of desmosomal integrity and cardiac function was corroborated in vivo, by treating heterozygous Pkp2c.1755delA knock-in mice. Long-term treatment with AAV9-PKP2 prevented cardiac dysfunction in 12-month-old Pkp2c.1755delA/WT mice, without affecting wild-type mice. These findings encourage clinical exploration of PKP2 gene therapy for patients with PKP2 haploinsufficiency.
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Affiliation(s)
- Eirini Kyriakopoulou
- Hubrecht Institute-KNAW and Utrecht University Medical Center, Utrecht, the Netherlands
| | - Danielle Versteeg
- Hubrecht Institute-KNAW and Utrecht University Medical Center, Utrecht, the Netherlands
| | - Hesther de Ruiter
- Hubrecht Institute-KNAW and Utrecht University Medical Center, Utrecht, the Netherlands
| | - Ilaria Perini
- Hubrecht Institute-KNAW and Utrecht University Medical Center, Utrecht, the Netherlands
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Gottingen (UMG), Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Yannic Döring
- Institute of Pharmacology and Toxicology, University Medical Center Gottingen (UMG), Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Lorena Zentilin
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Hoyee Tsui
- Hubrecht Institute-KNAW and Utrecht University Medical Center, Utrecht, the Netherlands
| | | | - Malte Tiburcy
- Institute of Pharmacology and Toxicology, University Medical Center Gottingen (UMG), Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Tim Meyer
- Institute of Pharmacology and Toxicology, University Medical Center Gottingen (UMG), Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Gottingen (UMG), Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
| | | | - Wolfram H. Zimmermann
- Institute of Pharmacology and Toxicology, University Medical Center Gottingen (UMG), Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Göttingen, Germany
| | - Mauro Giacca
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, King’s College London, London, UK
| | - Eva van Rooij
- Hubrecht Institute-KNAW and Utrecht University Medical Center, Utrecht, the Netherlands
- Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
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2
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Dorninger F, Kiss A, Rothauer P, Stiglbauer-Tscholakoff A, Kummer S, Fallatah W, Perera-Gonzalez M, Hamza O, König T, Bober MB, Cavallé-Garrido T, Braverman NE, Forss-Petter S, Pifl C, Bauer J, Bittner RE, Helbich TH, Podesser BK, Todt H, Berger J. Overlapping and Distinct Features of Cardiac Pathology in Inherited Human and Murine Ether Lipid Deficiency. Int J Mol Sci 2023; 24:1884. [PMID: 36768204 PMCID: PMC9914995 DOI: 10.3390/ijms24031884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/21/2023] Open
Abstract
Inherited deficiency in ether lipids, a subgroup of glycerophospholipids with unique biochemical and biophysical properties, evokes severe symptoms in humans resulting in a multi-organ syndrome. Mouse models with defects in ether lipid biosynthesis have widely been used to understand the pathophysiology of human disease and to study the roles of ether lipids in various cell types and tissues. However, little is known about the function of these lipids in cardiac tissue. Previous studies included case reports of cardiac defects in ether-lipid-deficient patients, but a systematic analysis of the impact of ether lipid deficiency on the mammalian heart is still missing. Here, we utilize a mouse model of complete ether lipid deficiency (Gnpat KO) to accomplish this task. Similar to a subgroup of human patients with rhizomelic chondrodysplasia punctata (RCDP), a fraction of Gnpat KO fetuses present with defects in ventricular septation, presumably evoked by a developmental delay. We did not detect any signs of cardiomyopathy but identified increased left ventricular end-systolic and end-diastolic pressure in middle-aged ether-lipid-deficient mice. By comprehensive electrocardiographic characterization, we consistently found reduced ventricular conduction velocity, as indicated by a prolonged QRS complex, as well as increased QRS and QT dispersion in the Gnpat KO group. Furthermore, a shift of the Wenckebach point to longer cycle lengths indicated depressed atrioventricular nodal function. To complement our findings in mice, we analyzed medical records and performed electrocardiography in ether-lipid-deficient human patients, which, in contrast to the murine phenotype, indicated a trend towards shortened QT intervals. Taken together, our findings demonstrate that the cardiac phenotype upon ether lipid deficiency is highly heterogeneous, and although the manifestations in the mouse model only partially match the abnormalities in human patients, the results add to our understanding of the physiological role of ether lipids and emphasize their importance for proper cardiac development and function.
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Affiliation(s)
- Fabian Dorninger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Attila Kiss
- Center for Biomedical Research, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Peter Rothauer
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090 Vienna, Austria
| | - Alexander Stiglbauer-Tscholakoff
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Structural Preclinical Imaging, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Stefan Kummer
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Währinger Straße 13, 1090 Vienna, Austria
| | - Wedad Fallatah
- Department of Genetic Medicine, King AbdulAziz University, Jeddah 21589, Saudi Arabia
- Department of Human Genetics and Pediatrics, Montreal Children’s Hospital, McGill University, 1001 Décarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Mireia Perera-Gonzalez
- Center for Biomedical Research, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Ouafa Hamza
- Center for Biomedical Research, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Theresa König
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Michael B. Bober
- Skeletal Dysplasia Program, Nemours Children’s Hospital, 1600 Rockland Road, Wilmington, DE 19803, USA
| | - Tiscar Cavallé-Garrido
- Department of Pediatrics, Division of Cardiology, Montreal Children’s Hospital, McGill University, 1001 Décarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Nancy E. Braverman
- Department of Human Genetics and Pediatrics, Montreal Children’s Hospital, McGill University, 1001 Décarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Sonja Forss-Petter
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Christian Pifl
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Jan Bauer
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Reginald E. Bittner
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Währinger Straße 13, 1090 Vienna, Austria
| | - Thomas H. Helbich
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Structural Preclinical Imaging, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Bruno K. Podesser
- Center for Biomedical Research, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Hannes Todt
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090 Vienna, Austria
| | - Johannes Berger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
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3
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Edwards AG, Mørk H, Stokke MK, Lipsett DB, Sjaastad I, Richard S, Sejersted OM, Louch WE. Sarcoplasmic Reticulum Calcium Release Is Required for Arrhythmogenesis in the Mouse. Front Physiol 2021; 12:744730. [PMID: 34712150 PMCID: PMC8546347 DOI: 10.3389/fphys.2021.744730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/20/2021] [Indexed: 11/23/2022] Open
Abstract
Dysfunctional sarcoplasmic reticulum Ca2+ handling is commonly observed in heart failure, and thought to contribute to arrhythmogenesis through several mechanisms. Some time ago we developed a cardiomyocyte-specific inducible SERCA2 knockout mouse, which is remarkable in the degree to which major adaptations to sarcolemmal Ca2+ entry and efflux overcome the deficit in SR reuptake to permit relatively normal contractile function. Conventionally, those adaptations would also be expected to dramatically increase arrhythmia susceptibility. However, that susceptibility has never been tested, and it is possible that the very rapid repolarization of the murine action potential (AP) allows for large changes in sarcolemmal Ca2+ transport without substantially disrupting electrophysiologic stability. We investigated this hypothesis through telemetric ECG recording in the SERCA2-KO mouse, and patch-clamp electrophysiology, Ca2+ imaging, and mathematical modeling of isolated SERCA2-KO myocytes. While the SERCA2-KO animals exhibit major (and unique) electrophysiologic adaptations at both the organ and cell levels, they remain resistant to arrhythmia. A marked increase in peak L-type calcium (ICaL) current and slowed ICaL decay elicited pronounced prolongation of initial repolarization, but faster late repolarization normalizes overall AP duration. Early afterdepolarizations were seldom observed in KO animals, and those that were observed exhibited a mechanism intermediate between murine and large mammal dynamical properties. As expected, spontaneous SR Ca2+ sparks and waves were virtually absent. Together these findings suggest that intact SR Ca2+ handling is an absolute requirement for triggered arrhythmia in the mouse, and that in its absence, dramatic changes to the major inward currents can be resisted by the substantial K+ current reserve, even at end-stage disease.
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Affiliation(s)
- Andrew G Edwards
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Halvor Mørk
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Mathis K Stokke
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - David B Lipsett
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Sylvain Richard
- Université de Montpellier, INSERM, CNRS, PhyMedExp, Montpellier, France
| | - Ole M Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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4
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Zebrafish, an In Vivo Platform to Screen Drugs and Proteins for Biomedical Use. Pharmaceuticals (Basel) 2021; 14:ph14060500. [PMID: 34073947 PMCID: PMC8225009 DOI: 10.3390/ph14060500] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 12/28/2022] Open
Abstract
The nearly simultaneous convergence of human genetics and advanced molecular technologies has led to an improved understanding of human diseases. At the same time, the demand for drug screening and gene function identification has also increased, albeit time- and labor-intensive. However, bridging the gap between in vitro evidence from cell lines and in vivo evidence, the lower vertebrate zebrafish possesses many advantages over higher vertebrates, such as low maintenance, high fecundity, light-induced spawning, transparent embryos, short generation interval, rapid embryonic development, fully sequenced genome, and some phenotypes similar to human diseases. Such merits have popularized the zebrafish as a model system for biomedical and pharmaceutical studies, including drug screening. Here, we reviewed the various ways in which zebrafish serve as an in vivo platform to perform drug and protein screening in the fields of rare human diseases, social behavior and cancer studies. Since zebrafish mutations faithfully phenocopy many human disorders, many compounds identified from zebrafish screening systems have advanced to early clinical trials, such as those for Adenoid cystic carcinoma, Dravet syndrome and Diamond-Blackfan anemia. We also reviewed and described how zebrafish are used to carry out environmental pollutant detection and assessment of nanoparticle biosafety and QT prolongation.
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5
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Kermorgant M, Ben Salem J, Iacovoni JS, Calise D, Dahan L, Guiard BP, Lopez S, Lairez O, Lasbories A, Nasr N, Pavy Le‐Traon A, Beaudry F, Senard J, Arvanitis DN. Cardiac sensory afferents modulate susceptibility to anxio-depressive behaviour in a mouse model of chronic heart failure. Acta Physiol (Oxf) 2021; 231:e13601. [PMID: 33316126 DOI: 10.1111/apha.13601] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/23/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022]
Abstract
AIM Impairments in cerebral structure and cognitive performance in chronic heart failure (CHF) are critical components of its comorbidity spectrum. Autonomic afferents that arise from cardiac sensory fibres show enhanced activity with CHF. Desensitization of these fibres by local application of resiniferatoxin (RTX) during myocardial infarction (MI) is known to prevent cardiac hypertrophy, sympathetic hyperactivity and CHF. Whether these afferents mediate cerebral allostasis is unknown. METHODS CHF was induced by myocardial infarction. To evaluate if cardiac afferents contribute to cerebral allostasis, RTX was acutely applied to the pericardial space in controls (RTX) and in MI treated animals (MI/RTX). Subjects were then evaluated in a series of behavioural tests recapitulating different symptoms of depressive disorders. Proteomics of the frontal cortices (FC) was performed to identify contributing proteins and pathways responsible for behavioural allostasis. RESULTS Desensitization of cardiac afferents relieves hallmarks of an anxio/depressive-like state in mice. Unique protein signatures and regulatory pathways in FCs isolated from each treatment reveal the degree of complexity inherent in the FC response to stresses originating in the heart. While cortices from the combined treatment (MI/RTX) did not retain protein signatures from the individual treatment groups, all three groups suffer dysregulation in circadian entrainment. CONCLUSION CHF is comorbid with an anxio/depressive-like state and ablation of cardiac afferents relieves the despair phenotype. The strikingly different proteomic profiles observed in FCs suggest that MI and RTX lead to unique brain-signalling patterns and that the combined treatment, potentially through destructive interference mechanisms, most closely resembles controls.
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Affiliation(s)
- Marc Kermorgant
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
| | - Jennifer Ben Salem
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Groupe de Recherche en Pharmacologie Animale du Québec (GREPAQ) Département de Biomédecine Vétérinaire Faculté de Médecine Vétérinaire Université de Montréal Saint Hyacinthe QC Canada
- Centre de recherche sur le cerveau et l’apprentissage (CIRCA) Université de Montréal Montréal QC Canada
| | - Jason S. Iacovoni
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
| | - Denis Calise
- INSERM DR Midi‐Pyrénées LimousinCentre Régional d’Exploration Fonctionnelle et Ressources Expérimentales Service Microchirurgie, (CREFRE‐US06, Rangueil) Toulouse France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale Centre de Biologie Intégrative Université de Toulouse Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
| | - Bruno P. Guiard
- Centre de Recherches sur la Cognition Animale Centre de Biologie Intégrative Université de Toulouse Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
| | - Sébastien Lopez
- Centre de Recherches sur la Cognition Animale Centre de Biologie Intégrative Université de Toulouse Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
| | - Olivier Lairez
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Fédération des services de cardiologie Hôpital RangueilUniversité de Toulouse III Toulouse France
| | - Antoine Lasbories
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
| | - Nathalie Nasr
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Département de Neurologie et Institut des Neurosciences CHU de ToulouseUniversité de Toulouse III Toulouse France
| | - Anne Pavy Le‐Traon
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Département de Neurologie et Institut des Neurosciences CHU de ToulouseUniversité de Toulouse III Toulouse France
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animale du Québec (GREPAQ) Département de Biomédecine Vétérinaire Faculté de Médecine Vétérinaire Université de Montréal Saint Hyacinthe QC Canada
- Centre de recherche sur le cerveau et l’apprentissage (CIRCA) Université de Montréal Montréal QC Canada
| | - Jean‐Michel Senard
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Département de Neurologie et Institut des Neurosciences CHU de ToulouseUniversité de Toulouse III Toulouse France
- Service de Pharmacologie Clinique CHU de ToulouseUniversité de Toulouse III Toulouse France
| | - Dina N Arvanitis
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
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6
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Offerhaus JA, Snelderwaard PC, Algül S, Faber JW, Riebel K, Jensen B, Boukens BJ. High heart rate associated early repolarization causes J-waves in both zebra finch and mouse. Physiol Rep 2021; 9:e14775. [PMID: 33709567 PMCID: PMC7953022 DOI: 10.14814/phy2.14775] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/22/2021] [Accepted: 02/04/2021] [Indexed: 11/24/2022] Open
Abstract
High heart rates are a feature of small endothermic—or warm‐blooded—mammals and birds. In small mammals, the QT interval is short, and local ventricular recordings reveal early repolarization that coincides with the J‐wave on the ECG, a positive deflection following the QRS complex. Early repolarization contributes to short QT‐intervals thereby enabling brief cardiac cycles and high heart rates. We therefore hypothesized high hearts rates associate with early repolarization and J‐waves on the ECG of endothermic birds. We tested this hypothesis by comparing isolated hearts of zebra finches and mice and recorded pseudo‐ECGs and optical action potentials (zebra finch, n = 8; mouse, n = 8). In both species, heart rate exceeded 300 beats per min, and total ventricular activation was fast (QRS < 10 ms). Ventricular activation progressed from the left to the right ventricle in zebra finch, whereas it progressed from apex‐to‐base in mouse. In both species, the early repolarization front followed the activation front, causing a positive J‐wave in the pseudo‐ECG. Inhibition of early repolarization by 4‐aminopyridine reduced J‐wave amplitude in both species. Action potential duration was similar between ventricles in zebra finch, whereas in mouse the left ventricular action potential was longer. Accordingly, late repolarization had opposite directions in zebra finch (left‐right) and mouse (right‐left). This caused a similar direction for the zebra finch J‐wave and T‐wave, whereas in the mouse they were discordant. Our findings demonstrate that early repolarization and the associated J‐wave may have evolved by convergence in association with high heart rates.
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Affiliation(s)
- Joost A Offerhaus
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam University Medical Center, Amsterdam, Netherlands
| | | | - Sila Algül
- Department of Medical Biology, Academic Medical Center, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Jaeike W Faber
- Department of Medical Biology, Academic Medical Center, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Katharina Riebel
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Bjarke Jensen
- Department of Medical Biology, Academic Medical Center, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Bastiaan J Boukens
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam University Medical Center, Amsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam University Medical Center, Amsterdam, Netherlands
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7
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Saadeh K, Fazmin IT. Mitochondrial Dysfunction Increases Arrhythmic Triggers and Substrates; Potential Anti-arrhythmic Pharmacological Targets. Front Cardiovasc Med 2021; 8:646932. [PMID: 33659284 PMCID: PMC7917191 DOI: 10.3389/fcvm.2021.646932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/26/2021] [Indexed: 12/31/2022] Open
Abstract
Incidence of cardiac arrhythmias increases significantly with age. In order to effectively stratify arrhythmic risk in the aging population it is crucial to elucidate the relevant underlying molecular mechanisms. The changes underlying age-related electrophysiological disruption appear to be closely associated with mitochondrial dysfunction. Thus, the present review examines the mechanisms by which age-related mitochondrial dysfunction promotes arrhythmic triggers and substrate. Namely, via alterations in plasmalemmal ionic currents (both sodium and potassium), gap junctions, cellular Ca2+ homeostasis, and cardiac fibrosis. Stratification of patients' mitochondrial function status permits application of appropriate anti-arrhythmic therapies. Here, we discuss novel potential anti-arrhythmic pharmacological interventions that specifically target upstream mitochondrial function and hence ameliorates the need for therapies targeting downstream changes which have constituted traditional antiarrhythmic therapy.
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Affiliation(s)
- Khalil Saadeh
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Ibrahim Talal Fazmin
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
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8
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Biasci V, Sacconi L, Cytrynbaum EN, Pijnappels DA, De Coster T, Shrier A, Glass L, Bub G. Universal mechanisms for self-termination of rapid cardiac rhythm. CHAOS (WOODBURY, N.Y.) 2020; 30:121107. [PMID: 33380016 DOI: 10.1063/5.0033813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 11/14/2020] [Indexed: 06/12/2023]
Abstract
Excitable media sustain circulating waves. In the heart, sustained circulating waves can lead to serious impairment or even death. To investigate factors affecting the stability of such waves, we have used optogenetic techniques to stimulate a region at the apex of a mouse heart at a fixed delay after the detection of excitation at the base of the heart. For long delays, rapid circulating rhythms can be sustained, whereas for shorter delays, there are paroxysmal bursts of activity that start and stop spontaneously. By considering the dependence of the action potential and conduction velocity on the preceding recovery time using restitution curves, as well as the reduced excitability (fatigue) due to the rapid excitation, we model prominent features of the dynamics including alternation of the duration of the excited phases and conduction times, as well as termination of the bursts for short delays. We propose that this illustrates universal mechanisms that exist in biological systems for the self-termination of such activities.
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Affiliation(s)
- Valentina Biasci
- Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Leonardo Sacconi
- National Institute of Optics, National Research Council, 50125 Florence, Italy
| | - Eric N Cytrynbaum
- Department of Mathematics, UBC, Vancouver British Columbia V6T 1Z2, Canada
| | - Daniël A Pijnappels
- Department of Cardiology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
| | - Tim De Coster
- Department of Cardiology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
| | - Alvin Shrier
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
| | - Leon Glass
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
| | - Gil Bub
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
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Clauss S, Bleyer C, Schüttler D, Tomsits P, Renner S, Klymiuk N, Wakili R, Massberg S, Wolf E, Kääb S. Animal models of arrhythmia: classic electrophysiology to genetically modified large animals. Nat Rev Cardiol 2020; 16:457-475. [PMID: 30894679 DOI: 10.1038/s41569-019-0179-0] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Arrhythmias are common and contribute substantially to cardiovascular morbidity and mortality. The underlying pathophysiology of arrhythmias is complex and remains incompletely understood, which explains why mostly only symptomatic therapy is available. The evaluation of the complex interplay between various cell types in the heart, including cardiomyocytes from the conduction system and the working myocardium, fibroblasts and cardiac immune cells, remains a major challenge in arrhythmia research because it can be investigated only in vivo. Various animal species have been used, and several disease models have been developed to study arrhythmias. Although every species is useful and might be ideal to study a specific hypothesis, we suggest a practical trio of animal models for future use: mice for genetic investigations, mechanistic evaluations or early studies to identify potential drug targets; rabbits for studies on ion channel function, repolarization or re-entrant arrhythmias; and pigs for preclinical translational studies to validate previous findings. In this Review, we provide a comprehensive overview of different models and currently used species for arrhythmia research, discuss their advantages and disadvantages and provide guidance for researchers who are considering performing in vivo studies.
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Affiliation(s)
- Sebastian Clauss
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany. .,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany.
| | - Christina Bleyer
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany
| | - Dominik Schüttler
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany
| | - Philipp Tomsits
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany
| | - Simone Renner
- Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZD (German Centre for Diabetes Research), Neuherberg, Germany
| | - Nikolai Klymiuk
- Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilians University Munich (LMU), Munich, Germany
| | - Reza Wakili
- Universitätsklinikum Essen, Westdeutsches Herz- und Gefäßzentrum Essen, Essen, Germany
| | - Steffen Massberg
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany
| | - Eckhard Wolf
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany.,Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZD (German Centre for Diabetes Research), Neuherberg, Germany
| | - Stefan Kääb
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Munich, Germany
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10
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Chadda KR, Edling CE, Valli H, Ahmad S, Huang CLH, Jeevaratnam K. Gene and Protein Expression Profile of Selected Molecular Targets Mediating Electrophysiological Function in Pgc-1α Deficient Murine Atria. Int J Mol Sci 2018; 19:ijms19113450. [PMID: 30400228 PMCID: PMC6274828 DOI: 10.3390/ijms19113450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 10/25/2018] [Accepted: 10/29/2018] [Indexed: 12/27/2022] Open
Abstract
Increases in the prevalence of obesity, insulin resistance, and metabolic syndrome has led to the increase of atrial fibrillation (AF) cases in the developed world. These AF risk factors are associated with mitochondrial dysfunction, previously modelled using peroxisome proliferator activated receptor-γ (PPARγ) coactivator-1 (Pgc-1)-deficient murine cardiac models. We explored gene and protein expression profiles of selected molecular targets related to electrophysiological function in murine Pgc-1α−/− atria. qPCR analysis surveyed genes related to Na+-K+-ATPase, K+ conductance, hyperpolarisation-activated cyclic nucleotide-gated (Hcn), Na+ channels, Ca2+ channels, and indicators for adrenergic and cholinergic receptor modulation. Western blot analysis for molecular targets specific to conduction velocity (Nav1.5 channel and gap junctions) was performed. Transcription profiles revealed downregulation of molecules related to Na+-K+-ATPase transport, Hcn-dependent pacemaker function, Na+ channel-dependent action potential activation and propagation, Ca2+ current generation, calsequestrin-2 dependent Ca2+ homeostasis, and adrenergic α1D dependent protection from hypertrophic change. Nav1.5 channel protein expression but not gap junction expression was reduced in Pgc-1α−/− atria compared to WT. Nav1.5 reduction reflects corresponding reduction in its gene expression profile. These changes, as well as the underlying Pgc-1α−/− alteration, suggest potential pharmacological targets directed towards either upstream PGC-1 signalling mechanisms or downstream ion channel changes.
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Affiliation(s)
- Karan R Chadda
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK.
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK.
| | - Charlotte E Edling
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK.
| | - Haseeb Valli
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK.
| | - Shiraz Ahmad
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK.
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK.
- Department of Biochemistry, Hopkins Building, University of Cambridge, Cambridge CB2 1QW, UK.
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK.
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK.
- School of Medicine, Perdana University-Royal College of Surgeons Ireland, Serdang 43400, Malaysia.
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11
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Hodgson P, Ireland J, Grunow B. Fish, the better model in human heart research? Zebrafish Heart aggregates as a 3D spontaneously cardiomyogenic in vitro model system. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:132-141. [PMID: 29729327 DOI: 10.1016/j.pbiomolbio.2018.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/04/2018] [Accepted: 04/27/2018] [Indexed: 12/25/2022]
Abstract
The zebrafish (ZF) has become an essential model for biomedical, pharmacological and eco-toxicological heart research. Despite the anatomical differences between fish and human hearts, similarities in cellular structure and conservation of genes as well as pathways across vertebrates have led to an increase in the popularity of ZF as a model for human cardiac research. ZF research benefits from an entirely sequenced genome, which allows us to establish and study cardiovascular mutants to better understand cardiovascular diseases. In this review, we will discuss the importance of in vitro model systems for cardiac research and summarise results of in vitro 3D heart-like cell aggregates, consisting of myocardial tissue formed spontaneously from enzymatically digested whole embryonic ZF larvae (Zebrafish Heart Aggregate - ZFHA). We will give an overview of the similarities and differences of ZF versus human hearts and highlight why ZF complement established mammalian models (i.e. murine and large animal models) for cardiac research. At this stage, the ZFHA model system is being refined into a high-throughput (more ZFHA generated than larvae prepared) and stable in vitro test system to accomplish the same longevity of previously successful salmonid models. ZFHA have potential for the use of high-throughput-screenings of different factors like small molecules, nucleic acids, proteins and lipids which is difficult to achieve in the zebrafish in vivo screening models with lethal mutations as well as to explore ion channel disorders and to find appropriate drugs for safety screening.
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Affiliation(s)
- Patricia Hodgson
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK; Salford Royal NHS Foundation Trust, Stott Lane, Salford M6 8HD, UK
| | - Jake Ireland
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK; School of Chemistry, Materials Science, and Engineering, Hilmer Building, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Bianka Grunow
- University Medicine Greifswald, Institute of Physiology, Greifswalder Str. 11C, 17495 Karlsburg, Germany; Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK.
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12
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Valli H, Ahmad S, Chadda KR, Al-Hadithi ABAK, Grace AA, Jeevaratnam K, Huang CLH. Age-dependent atrial arrhythmic phenotype secondary to mitochondrial dysfunction in Pgc-1β deficient murine hearts. Mech Ageing Dev 2017; 167:30-45. [PMID: 28919427 PMCID: PMC5652526 DOI: 10.1016/j.mad.2017.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/24/2017] [Accepted: 09/13/2017] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Ageing and several age-related chronic conditions including obesity, insulin resistance and hypertension are associated with mitochondrial dysfunction and represent independent risk factors for atrial fibrillation (AF). MATERIALS AND METHODS Atrial arrhythmogenesis was investigated in Langendorff-perfused young (3-4 month) and aged (>12 month), wild type (WT) and peroxisome proliferator activated receptor-γ coactivator-1β deficient (Pgc-1β-/-) murine hearts modeling age-dependent chronic mitochondrial dysfunction during regular pacing and programmed electrical stimulation (PES). RESULTS AND DISCUSSION The Pgc-1β-/- genotype was associated with a pro-arrhythmic phenotype progressing with age. Young and aged Pgc-1β-/- hearts showed compromised maximum action potential (AP) depolarization rates, (dV/dt)max, prolonged AP latencies reflecting slowed action potential (AP) conduction, similar effective refractory periods and baseline action potential durations (APD90) but shortened APD90 in APs in response to extrasystolic stimuli at short stimulation intervals. Electrical properties of APs triggering arrhythmia were similar in WT and Pgc-1β-/- hearts. Pgc-1β-/- hearts showed accelerated age-dependent fibrotic change relative to WT, with young Pgc-1β-/- hearts displaying similar fibrotic change as aged WT, and aged Pgc-1β-/- hearts the greatest fibrotic change. Mitochondrial deficits thus result in an arrhythmic substrate, through slowed AP conduction and altered repolarisation characteristics, arising from alterations in electrophysiological properties and accelerated structural change.
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Affiliation(s)
- Haseeb Valli
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Shiraz Ahmad
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Karan R Chadda
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom; Faculty of Health and Medical Sciences, University of Surrey, GU2 7AL, Guildford, Surrey, United Kingdom
| | - Ali B A K Al-Hadithi
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Andrew A Grace
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom
| | - Kamalan Jeevaratnam
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom; Faculty of Health and Medical Sciences, University of Surrey, GU2 7AL, Guildford, Surrey, United Kingdom; PU-RCSI School of Medicine, Perdana University, 43400, Serdang, Selangor Darul Ehsan, Malaysia
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom; Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.
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13
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Dressler FF, Bodi I, Menza M, Moss R, Bugger H, Bode C, Behrends JC, Seemann G, Odening KE. Interregional electro-mechanical heterogeneity in the rabbit myocardium. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:344-355. [PMID: 28655649 DOI: 10.1016/j.pbiomolbio.2017.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND Increased electrical heterogeneity has been causatively linked to arrhythmic disorders, yet the knowledge about physiological heterogeneity remains incomplete. This study investigates regional electro-mechanical heterogeneities in rabbits, one of the key animal models for arrhythmic disorders. METHODS AND FINDINGS 7 wild-type rabbits were examined by phase-contrast magnetic resonance imaging in vivo to assess cardiac wall movement velocities. Using a novel data-processing algorithm regional contraction-like profiles were calculated. Contraction started earlier and was longer in left ventricular (LV) apex than base. Patch clamp recordings showed longer action potentials (AP) in LV apex compared to the base of LV, septum, and right ventricle. Western blots of cardiac ion channels and calcium handling proteins showed lower expression of Cav1.2, KvLQT1, Kv1.4, NCX and Phospholamban in LV apex vs. base. A single-cell in silico model integrating the quantitative regional differences in ion channels reproduced a longer contraction and longer AP in apex vs. base. CONCLUSIONS Apico-basal electro-mechanical heterogeneity is physiologically present in the healthy rabbit heart. An apico-basal electro-mechanical gradient exists with longer APD and contraction duration in the apex and associated regionally heterogeneous expression of five key proteins. This pattern of apical mechanical dominance probably serves to increase pumping efficiency.
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Affiliation(s)
- Franz F Dressler
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Ilona Bodi
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Marius Menza
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Department of Medical Physics, Medical Center - University of Freiburg, Breisacher Straße 60a, 79106 Freiburg, Germany
| | - Robin Moss
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76128 Karlsruhe, Germany; Institute for Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Center - University of Freiburg, Elsaesserstrasse 2q, 79110 Freiburg, Germany
| | - Heiko Bugger
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Christoph Bode
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Jan C Behrends
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Department of Physiology, Laboratory for Membrane Physiology and -Technology, University of Freiburg, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany
| | - Gunnar Seemann
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76128 Karlsruhe, Germany; Institute for Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Center - University of Freiburg, Elsaesserstrasse 2q, 79110 Freiburg, Germany
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Institute for Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Center - University of Freiburg, Elsaesserstrasse 2q, 79110 Freiburg, Germany.
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14
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Naumenko N, Huusko J, Tuomainen T, Koivumäki JT, Merentie M, Gurzeler E, Alitalo K, Kivelä R, Ylä-Herttuala S, Tavi P. Vascular Endothelial Growth Factor-B Induces a Distinct Electrophysiological Phenotype in Mouse Heart. Front Physiol 2017; 8:373. [PMID: 28620319 PMCID: PMC5450225 DOI: 10.3389/fphys.2017.00373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/18/2017] [Indexed: 12/22/2022] Open
Abstract
Vascular endothelial growth factor B (VEGF-B) is a potent mediator of vascular, metabolic, growth, and stress responses in the heart, but the effects on cardiac muscle and cardiomyocyte function are not known. The purpose of this study was to assess the effects of VEGF-B on the energy metabolism, contractile, and electrophysiological properties of mouse cardiac muscle and cardiac muscle cells. In vivo and ex vivo analysis of cardiac-specific VEGF-B TG mice indicated that the contractile function of the TG hearts was normal. Neither the oxidative metabolism of isolated TG cardiomyocytes nor their energy substrate preference showed any difference to WT cardiomyocytes. Similarly, myocyte Ca2+ signaling showed only minor changes compared to WT myocytes. However, VEGF-B overexpression induced a distinct electrophysiological phenotype characterized by ECG changes such as an increase in QRSp time and decreases in S and R amplitudes. At the level of isolated TG cardiomyocytes, these changes were accompanied with decreased action potential upstroke velocity and increased duration (APD60–70). These changes were partly caused by downregulation of sodium current (INa) due to reduced expression of Nav1.5. Furthermore, TG myocytes had alterations in voltage-gated K+ currents, namely decreased density of transient outward current (Ito) and total K+ current (Ipeak). At the level of transcription, these were accompanied by downregulation of Kv channel-interacting protein 2 (Kcnip2), a known modulatory subunit for Kv4.2/3 channel. Cardiac VEGF-B overexpression induces a distinct electrophysiological phenotype including remodeling of cardiomyocyte ion currents, which in turn induce changes in action potential waveform and ECG.
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Affiliation(s)
- Nikolay Naumenko
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
| | - Jenni Huusko
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
| | - Tomi Tuomainen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
| | - Jussi T Koivumäki
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
| | - Mari Merentie
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
| | - Erika Gurzeler
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
| | - Kari Alitalo
- Wihuri Research Institute and Translational Cancer Biology Program, University of Helsinki, Biomedicum HelsinkiHelsinki, Finland
| | - Riikka Kivelä
- Wihuri Research Institute and Translational Cancer Biology Program, University of Helsinki, Biomedicum HelsinkiHelsinki, Finland
| | - Seppo Ylä-Herttuala
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland.,Heart Center and Gene Therapy Unit, Kuopio University HospitalKuopio, Finland
| | - Pasi Tavi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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16
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Choy L, Yeo JM, Tse V, Chan SP, Tse G. Cardiac disease and arrhythmogenesis: Mechanistic insights from mouse models. IJC HEART & VASCULATURE 2016; 12:1-10. [PMID: 27766308 PMCID: PMC5064289 DOI: 10.1016/j.ijcha.2016.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 05/02/2016] [Indexed: 12/19/2022]
Abstract
The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony. Last but not least, pharmacological models, despite being simplistic, have enabled us to understand the physiological mechanisms of arrhythmias and evaluate the anti-arrhythmic properties of experimental agents, such as gap junction modulators, that may be exert therapeutic effects in other cardiac diseases. In this article, we examine these in turn, demonstrating that primary inherited arrhythmic syndromes are now recognized to be more complex than abnormality in a particular ion channel, involving alterations in gene expression and structural remodelling. Conversely, in cardiomyopathies and heart failure, mutations in ion channels and proteins have been identified as underlying causes, and electrophysiological remodelling are recognized pathological features. Transgenic techniques causing mutagenesis in mice are extremely powerful in dissecting the relative contributions of different genes play in producing disease phenotypes. Mouse models can serve as useful systems in which to explore how protein defects contribute to arrhythmias and direct future therapy.
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Affiliation(s)
- Lois Choy
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Jie Ming Yeo
- School of Medicine, Imperial College London, SW7 2AZ, UK
| | - Vivian Tse
- Department of Physiology, McGill University, Canada
| | - Shing Po Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Gary Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
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17
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Abstract
The QT interval reflects the time between the depolarization of ventricles until their repolarization and is usually used as a predictive marker for the occurrence of arrhythmias. This parameter varies with the heart rate, expressed as the RR interval (time between two successive ventricular depolarizations). To calculate the QT independently of the RR, correction formulae are currently used. In mice, the QT-RR relationship as such has never been studied in conscious animals, and correction formulas are mainly empirical. In the present paper we studied how QT varies when the RR changes physiologically (comparison of nocturnal and diurnal periods) or after dosing mice with tachycardic agents (norepinephrine or nitroprusside). Our results show that there is significant variability of QT and RR in a given condition, resulting in the need to average at least 200 consecutive complexes to accurately compare the QT. Even following this method, no obvious shortening of the QT was observed with increased heart rate, regardless of whether or not this change occurs abruptly. In conclusion, the relationship between QT and RR in mice is weak, which renders the use of correction formulae inappropriate and misleading in this species.
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18
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Kurokawa J, Sasano T, Kodama M, Li M, Ebana Y, Harada N, Honda SI, Nakaya H, Furukawa T. Aromatase knockout mice reveal an impact of estrogen on drug-induced alternation of murine electrocardiography parameters. J Toxicol Sci 2016; 40:339-48. [PMID: 25972195 DOI: 10.2131/jts.40.339] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Our in vitro characterization showed that physiological concentrations of estrogen partially suppressed the I(Kr) channel current in guinea pig ventricular myocytes and the human ether-a-go-go-related gene (hERG) channel currents in CHO-K1 cells regardless of estrogen receptor signaling and revealed that the partially suppressed hERG currents enhanced the sensitivity to the hERG blocker E-4031. To obtain in vivo proof-of-concept data to support the effects of estrogen on cardiac electrophysiology, we here employed an aromatase knockout mouse as an in vivo estrogen-null model and compared the acute effects of E-4031 on cardiac electrophysiological parameters with those in wild-type mice (C57/BL6J) by recording surface electrocardiogram (ECG). The ablation of circulating estrogens blunted the effects of E-4031 on heart rate and QT interval in mice under a denervation condition. Our result provides in vivo proof of principle and demonstrates that endogenous estrogens increase the sensitivity of E-4031 to cardiac electrophysiology.
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Affiliation(s)
- Junko Kurokawa
- Department of Bio-Informational Pharmacology, Medical Research Institute, Tokyo Medical Dental University
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19
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Efficacy and safety of myocardial gene transfer of adenovirus, adeno-associated virus and lentivirus vectors in the mouse heart. Gene Ther 2015; 23:296-305. [PMID: 26704723 DOI: 10.1038/gt.2015.114] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/20/2015] [Accepted: 12/21/2015] [Indexed: 01/18/2023]
Abstract
Gene therapy is a promising new treatment option for cardiac diseases. For finding the most suitable and safe vector for cardiac gene transfer, we delivered adenovirus (AdV), adeno-associated virus (AAV) and lentivirus (LeV) vectors into the mouse heart with sophisticated closed-chest echocardiography-guided intramyocardial injection method for comparing them with regards to transduction efficiency, myocardial damage, effects on the left ventricular function and electrocardiography (ECG). AdV had the highest transduction efficiency in cardiomyocytes followed by AAV2 and AAV9, and the lowest efficiency was seen with LeV. The local myocardial inflammation and fibrosis in the left ventricle (LV) was proportional to transduction efficiency. AdV caused LV dilatation and systolic dysfunction. Neither of the locally injected AAV serotypes impaired the LV systolic function, but AAV9 caused diastolic dysfunction to some extent. LeV did not affect the cardiac function. We also studied systemic delivery of AAV9, which led to transduction of cardiomyocytes throughout the myocardium. However, also diffuse fibrosis was present leading to significantly impaired LV systolic and diastolic function and pathological ECG changes. Compared with widely used AdV vector, AAV2, AAV9 and LeV were less effective in transducing cardiomyocytes but also less harmful. Local administration of AAV9 was safer and more efficient compared with systemic administration.
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20
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Merentie M, Lipponen JA, Hedman M, Hedman A, Hartikainen J, Huusko J, Lottonen-Raikaslehto L, Parviainen V, Laidinen S, Karjalainen PA, Ylä-Herttuala S. Mouse ECG findings in aging, with conduction system affecting drugs and in cardiac pathologies: Development and validation of ECG analysis algorithm in mice. Physiol Rep 2015; 3:3/12/e12639. [PMID: 26660552 PMCID: PMC4760442 DOI: 10.14814/phy2.12639] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mouse models are extremely important in studying cardiac pathologies and related electrophysiology, but very few mouse ECG analysis programs are readily available. Therefore, a mouse ECG analysis algorithm was developed and validated. Surface ECG (lead II) was acquired during transthoracic echocardiography from C57Bl/6J mice under isoflurane anesthesia. The effect of aging was studied in young (2–3 months), middle‐aged (14 months) and old (20–24 months) mice. The ECG changes associated with pharmacological interventions and common cardiac pathologies, that is, acute myocardial infarction (AMI) and progressive left ventricular hypertrophy (LVH), were studied. The ECG raw data were analyzed with an in‐house ECG analysis program, modified specially for mouse ECG. Aging led to increases in P‐wave duration, atrioventricular conduction time (PQ interval), and intraventricular conduction time (QRS complex width), while the R‐wave amplitude decreased. In addition, the prevalence of arrhythmias increased during aging. Anticholinergic atropine shortened PQ time, and beta blocker metoprolol and calcium‐channel blocker verapamil increased PQ interval and decreased heart rate. The ECG changes after AMI included early JT elevation, development of Q waves, decreased R‐wave amplitude, and later changes in JT/T segment. In progressive LVH model, QRS complex width was increased at 2 and especially 4 weeks timepoint, and also repolarization abnormalities were seen. Aging, drugs, AMI, and LVH led to similar ECG changes in mice as seen in humans, which could be reliably detected with this new algorithm. The developed method will be very useful for studies on cardiovascular diseases in mice.
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Affiliation(s)
- Mari Merentie
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Jukka A Lipponen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Marja Hedman
- Heart Center, Kuopio University Hospital, Kuopio, Finland Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Antti Hedman
- Heart Center, Kuopio University Hospital, Kuopio, Finland
| | | | - Jenni Huusko
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Line Lottonen-Raikaslehto
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Viktor Parviainen
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Svetlana Laidinen
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Pasi A Karjalainen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Seppo Ylä-Herttuala
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland Science Service Center, Kuopio University Hospital, Kuopio, Finland Gene Therapy Unit, Kuopio University Hospital, Kuopio, Finland
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21
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Remodeling of the intercalated disc related to aging in the mouse heart. J Cardiol 2015; 68:261-8. [PMID: 26584974 DOI: 10.1016/j.jjcc.2015.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 08/10/2015] [Accepted: 09/08/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND Aging is related to declined cardiac hemodynamic function. As pumping performance may be significantly related to slowed ventricular depolarization and non-synchronous contraction, we hypothesized that aging may cause dysfunction of intercalated disc (ID), which is the structure responsible for intercellular electrical communication between cardiomyocytes. METHODS Male C57BL/6J mice were used for the study at two ages: 4 and 24 months. Electrocardiographic recording was made to analyze the time of ventricular depolarization. Then mice were killed, and the hearts were harvested for examination in transmission electron microscopy (TEM) and immunofluorescence imaging. The expression of connexin 43 (Cx43), N-cadherin, and β-catenin in the myocardium of the left ventricle was evaluated using Western blotting. RESULTS In senescent mice, analysis of averaged QRS complex showed its significant prolongation. At the ultrastructural level, we found frequent disruptions of the ID (affecting 29±5% of them), mainly at the site of adherens junction, with relatively preserved desmosomal intercellular connections and diminished number of gap junctions. Western blotting revealed significantly decreased abundance of Cx43 protein in aged animals, which may cause slowed impulse propagation through the gap junctions and contribute to the observed electrocardiographic alterations. The level of RNA for Cx43 is similar between young and old animals, which suggests a post-transcriptional mechanism of Cx43 protein downregulation. CONCLUSIONS Our study shows age-related disorganization of ID, which may be responsible for slowed conduction of the depolarization wave within the heart, and supports the hypothesis of cardiac dysfunction in senescence.
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22
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Boukens BJ, Rivaud MR, Rentschler S, Coronel R. Misinterpretation of the mouse ECG: 'musing the waves of Mus musculus'. J Physiol 2014; 592:4613-26. [PMID: 25260630 DOI: 10.1113/jphysiol.2014.279380] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The ECG is a primary diagnostic tool in patients suffering from heart disease, underscoring the importance of understanding factors contributing to normal and abnormal electrical patterns. Over the past few decades, transgenic mouse models have been increasingly used to study pathophysiological mechanisms of human heart diseases. In order to allow extrapolation of insights gained from murine models to the human condition, knowledge of the similarities and differences between the mouse and human ECG is of crucial importance. In this review, we briefly discuss the physiological mechanisms underlying differences between the baseline ECG of humans and mice, and provide a framework for understanding how these inherent differences are relevant to the interpretation of the mouse ECG during pathology and to the translation of the results from the mouse to man.
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Affiliation(s)
- Bastiaan J Boukens
- Department of Biomedical Engineering, Washington University, St Louis, MO 63119, USA
| | - Mathilde R Rivaud
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Stacey Rentschler
- Department of Medicine, Cardiovascular Division, and Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Ruben Coronel
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France
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23
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Cardiac electrophysiological alterations in heart/muscle-specific manganese-superoxide dismutase-deficient mice: prevention by a dietary antioxidant polyphenol. BIOMED RESEARCH INTERNATIONAL 2014; 2014:704291. [PMID: 24772433 PMCID: PMC3977505 DOI: 10.1155/2014/704291] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 02/12/2014] [Indexed: 11/23/2022]
Abstract
Cardiac electrophysiological alterations induced by chronic exposure to reactive oxygen species and protective effects of dietary antioxidant have not been thoroughly examined. We recorded surface electrocardiograms (ECG) and evaluated cellular electrophysiological abnormalities in enzymatically-dissociated left ventricular (LV) myocytes in heart/muscle-specific manganese-superoxide dismutase-deficient (H/M-Sod2−/−) mice, which exhibit dilated cardiomyopathy due to increased oxidative stress. We also investigated the influences of intake of apple polyphenols (AP) containing mainly procyanidins with potent antioxidant activity. The QRS and QT intervals of ECG recorded in H/M-Sod2−/− mice were prolonged. The effective refractory period in the LV myocardium of H/M-Sod2−/− mice was prolonged, and susceptibility to ventricular tachycardia or fibrillation induced by rapid ventricular pacing was increased. Action potential duration in H/M-Sod2−/− LV myocytes was prolonged, and automaticity was enhanced. The density of the inwardly rectifier K+ current (IK1) was decreased in the LV cells of H/M-Sod2−/− mice. The AP intake partially improved these electrophysiological alterations and extended the lifespan in H/M-Sod2−/− mice. Thus, chronic exposure of the heart to oxidative stress produces a variety of electrophysiological abnormalities, increased susceptibility to ventricular arrhythmias, and action potential changes associated with the reduced density of IK1. Dietary intake of antioxidant nutrients may prevent oxidative stress-induced electrophysiological disturbances.
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24
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Speerschneider T, Thomsen MB. Physiology and analysis of the electrocardiographic T wave in mice. Acta Physiol (Oxf) 2013; 209:262-71. [PMID: 24119104 DOI: 10.1111/apha.12172] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 08/20/2013] [Accepted: 09/24/2013] [Indexed: 01/28/2023]
Abstract
AIM The murine electrocardiogram (ECG) is a valuable tool in cardiac research, although the definition of the T wave has been a matter of debate for several years potentially leading to incomparable data. By this study, we seek to make a clear definition of the murine T wave. Moreover, we investigate the consequences of performing QT interval correction in anaesthetized mice. METHODS Electrocardiograms from conscious mice were recorded by implanted telemetry devices. Surface ECGs were recorded from anaesthetized mice before and during pharmacological interventions, ventricular ischaemia and heart failure. Right atrial pacing was performed to evaluate the relationship between heart rate and QT intervals. RESULTS Electrocardiogram traces of conscious and anaesthetized mice (lead II) showed separable positive J waves and negative T waves. The end of the T wave was determined as the point where the T wave returned to the isoelectric line. Atrial pacing revealed that the duration of the QT interval is independent of heart rate in anaesthetized mice. The calcium channel blocker, verapamil, prolonged the PR interval; however, the polarities of the J and T waves were not changed. Local cardiac ischaemia and β-adrenergic stimulation caused indistinguishable positive J and T waves. In contrast, chronic heart failure caused entirely negative J and T waves. In every case, the end of the T wave was clearly distinguishable on the ECG. CONCLUSION The end of the T wave is readily available from conscious and anaesthetized mice. Heart rate correction of QT interval duration in the anaesthetized mouse is not recommended.
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Affiliation(s)
- T. Speerschneider
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; Danish National Research Foundation Centre for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
| | - M. B. Thomsen
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; Danish National Research Foundation Centre for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
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25
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Arechederra M, Carmona R, González-Nuñez M, Gutiérrez-Uzquiza A, Bragado P, Cruz-González I, Cano E, Guerrero C, Sánchez A, López-Novoa JM, Schneider MD, Maina F, Muñoz-Chápuli R, Porras A. Met signaling in cardiomyocytes is required for normal cardiac function in adult mice. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2204-15. [PMID: 23994610 DOI: 10.1016/j.bbadis.2013.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 08/02/2013] [Accepted: 08/20/2013] [Indexed: 11/30/2022]
Abstract
Hepatocyte growth factor (HGF) and its receptor, Met, are key determinants of distinct developmental processes. Although HGF exerts cardio-protective effects in a number of cardiac pathologies, it remains unknown whether HGF/Met signaling is essential for myocardial development and/or physiological function in adulthood. We therefore investigated the requirement of HGF/Met signaling in cardiomyocyte for embryonic and postnatal heart development and function by conditional inactivation of the Met receptor in cardiomyocytes using the Cre-α-MHC mouse line (referred to as α-MHCMet-KO). Although α-MHCMet-KO mice showed normal heart development and were viable and fertile, by 6 months of age, males developed cardiomyocyte hypertrophy, associated with interstitial fibrosis. A significant upregulation in markers of myocardial damage, such as β-MHC and ANF, was also observed. By the age of 9 months, α-MHCMet-KO males displayed systolic cardiac dysfunction. Mechanistically, we provide evidence of a severe imbalance in the antioxidant defenses in α-MHCMet-KO hearts involving a reduced expression and activity of catalase and superoxide dismutase, with consequent reactive oxygen species accumulation. Similar anomalies were observed in females, although with a slower kinetics. We also found that Met signaling down-regulation leads to an increase in TGF-β production and a decrease in p38MAPK activation, which may contribute to phenotypic alterations displayed in α-MHCMet-KO mice. Consistently, we show that HGF acts through p38α to upregulate antioxidant enzymes in cardiomyocytes. Our results highlight that HGF/Met signaling in cardiomyocytes plays a physiological cardio-protective role in adult mice by acting as an endogenous regulator of heart function through oxidative stress control.
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Affiliation(s)
- María Arechederra
- Departamento de Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Ciudad Universitaria, 28040 Madrid, Spain
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26
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The Lambeth Conventions (II): Guidelines for the study of animal and human ventricular and supraventricular arrhythmias. Pharmacol Ther 2013; 139:213-48. [DOI: 10.1016/j.pharmthera.2013.04.008] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 12/17/2022]
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27
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Kaese S, Frommeyer G, Verheule S, van Loon G, Gehrmann J, Breithardt G, Eckardt L. The ECG in cardiovascular-relevant animal models of electrophysiology. Herzschrittmacherther Elektrophysiol 2013; 24:84-91. [PMID: 23740318 DOI: 10.1007/s00399-013-0260-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 06/02/2023]
Abstract
The most frequently used animal species in experimental cardiac electrophysiology are mice, rabbits, and dogs. Murine and human electrocardiograms (ECGs) show salient differences, including the occurrence of a pronounced J-wave and a less distinctive T-wave in the murine ECG. Mouse models can resemble human cardiac arrhythmias, although mice differ from human in cardiac electrophysiology. Thus, arrhythmia mechanisms in mice may differ from those in humans and should be transferred to the human situation with caution. Further relevant cardiovascular animal models are rabbits, dogs, and minipigs, as they show similarities of cardiac ion channel distribution with the human heart and are suitable to study ventricular repolarization or pro- and antiarrhythmic drug effects. ECG recordings in large animals like goats and horses are feasible. Both goats and horses are a suitable animal model to study atrial fibrillation (AF) mechanisms. Horses frequently show spontaneous AF due to their high vagal tone and large atria. The zebrafish has become an important animal model. Models in "exotic" animals such as kangaroos may be suitable for particular studies.
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Affiliation(s)
- Sven Kaese
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Muenster, Muenster, Germany.
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28
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Shi C, Wang X, Dong F, Wang Y, Hui J, Lin Z, Yang J, Xu Y. Temporal alterations and cellular mechanisms of transmural repolarization during progression of mouse cardiac hypertrophy and failure. Acta Physiol (Oxf) 2013; 208:95-110. [PMID: 23356774 DOI: 10.1111/apha.12071] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/29/2012] [Accepted: 01/23/2013] [Indexed: 01/02/2023]
Abstract
AIM The remodelling of transmural dispersion of repolarization (TDR) in human heart failure (HF) and in different animal models of cardiac hypertrophy or HF remains a controversial topic. We hypothesize that TDR may exhibit temporal alterations, depending on the stage of the disease. METHODS We systematically investigated the temporal alterations of TDR during the development of cardiac hypertrophy and HF in the mouse pressure-overload model using electrophysiological and molecular biology techniques. RESULTS A progressive prolongation of QT interval and changes in the amplitude of the J wave at 2, 5, 9 and 13 weeks were found in anesthetized aorta-banded mice. Action potential duration (APD) at 90% repolarization (APD90) in subendocardial myocytes of the left ventricular free wall remained unchanged at the hypertrophic stage (2 and 5 weeks), but was significantly prolonged in HF mice at 9 and 13 weeks. However, APD90 in subepicardial myocytes exhibited a significant prolongation at 2 weeks and did not progressively extend from 2 weeks to 13 weeks in banded mice. Thus, non-parallel prolongation of APD in subendocardial and subepicardial myocytes led to a reduction in TDR at hypertrophic stage and an amplification of TDR at HF stage. Further experiments revealed that asynchronous down-regulation of voltage-dependent potassium currents (I(to,f), I(K,slow) and I(ss)) and L-type calcium currents (I(Ca-L)) in subendocardial and subepicardial myocytes may contribute to the dynamic remodelling of transmural APD. CONCLUSION The two distinct TDR modes were revealed during the progression of mouse cardiac hypertrophy and failure, indicating that the remodelling of TDR depends on the stage of the disease.
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Affiliation(s)
| | - X. Wang
- The Third Hospital of Hebei Medical University; Shijiazhuang; China
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29
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Kobayashi T, Ito T, Yamada S, Kuniyoshi N, Shiomi M. Electrocardiograms corresponding to the development of myocardial infarction in anesthetized WHHLMI rabbits (Oryctolagus cuniculus), an animal model for familial hypercholesterolemia. Comp Med 2012; 62:409-418. [PMID: 23114045 PMCID: PMC3472606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 12/29/2011] [Accepted: 03/08/2012] [Indexed: 06/01/2023]
Abstract
The aim of this study was to determine whether features indicative of myocardial ischemia occur in the electrocardiograms (ECG) in myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits, an animal model for human familial hypercholesterolemia. ECG were recorded in 110 anesthetized WHHLMI rabbits (age, 10 to 39 mo) by using unipolar and bipolar limb leads with or without chest leads. We noted the following electrocardiographic changes: T wave inversion (37.4%), ST segment depression (31.8%), deep Q wave (16.3%), reduced R wave amplitude (7.3%), ST segment elevation (2.7%), and high T wave (1.8%). These ECG changes resembled those in human patients with coronary heart disease. Histopathologic examination revealed that the left ventricular wall showed acute myocardial lesions, including loss of cross-striations, vacuolar degeneration, coagulation necrosis of cardiac myocytes, and edema between myofibrils, in addition to chronic myocardial lesions such as myocardial fibrosis. The coronary arteries that caused these ECG changes were severely stenosed due to atherosclerotic lesions. Ischemic ECG changes corresponded to the locations of the myocardial lesions. Normal ECG waveforms were similar between WHHLMI rabbits and humans, in contrast to the large differences between rabbits and mice or rats. In conclusion, ischemic ECG changes in WHHLMI rabbits reflect the location of myocardial lesions, making this model useful for studying coronary heart disease.
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Affiliation(s)
- Tsutomu Kobayashi
- Institute for Experimental Animals, Division of Cardiovascular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
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30
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Pietka TA, Sulkin MS, Kuda O, Wang W, Zhou D, Yamada KA, Yang K, Su X, Gross RW, Nerbonne JM, Efimov IR, Abumrad NA. CD36 protein influences myocardial Ca2+ homeostasis and phospholipid metabolism: conduction anomalies in CD36-deficient mice during fasting. J Biol Chem 2012; 287:38901-12. [PMID: 23019328 DOI: 10.1074/jbc.m112.413609] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Sarcolemmal CD36 facilitates myocardial fatty acid (FA) uptake, which is markedly reduced in CD36-deficient rodents and humans. CD36 also mediates signal transduction events involving a number of cellular pathways. In taste cells and macrophages, CD36 signaling was recently shown to regulate store-responsive Ca(2+) flux and activation of Ca(2+)-dependent phospholipases A(2) that cycle polyunsaturated FA into phospholipids. It is unknown whether CD36 deficiency influences myocardial Ca(2+) handling and phospholipid metabolism, which could compromise the heart, typically during stresses. Myocardial function was examined in fed or fasted (18-22 h) CD36(-/-) and WT mice. Echocardiography and telemetry identified conduction anomalies that were associated with the incidence of sudden death in fasted CD36(-/-) mice. No anomalies or death occurred in WT mice during fasting. Optical imaging of perfused hearts from fasted CD36(-/-) mice documented prolongation of Ca(2+) transients. Consistent with this, knockdown of CD36 in cardiomyocytes delayed clearance of cytosolic Ca(2+). Hearts of CD36(-/-) mice (fed or fasted) had 3-fold higher SERCA2a and 40% lower phospholamban levels. Phospholamban phosphorylation by protein kinase A (PKA) was enhanced after fasting reflecting increased PKA activity and cAMP levels in CD36(-/-) hearts. Abnormal Ca(2+) homeostasis in the CD36(-/-) myocardium associated with increased lysophospholipid content and a higher proportion of 22:6 FA in phospholipids suggests altered phospholipase A(2) activity and changes in membrane dynamics. The data support the role of CD36 in coordinating Ca(2+) homeostasis and lipid metabolism and the importance of this role during myocardial adaptation to fasting. Potential relevance of the findings to CD36-deficient humans would need to be determined.
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Affiliation(s)
- Terri A Pietka
- Center for Human Nutrition, Washington University, St. Louis, Missouri 63110, USA
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31
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Boukens BJ, Hoogendijk MG, Verkerk AO, Linnenbank A, van Dam P, Remme CA, Fiolet JW, Opthof T, Christoffels VM, Coronel R. Early repolarization in mice causes overestimation of ventricular activation time by the QRS duration. Cardiovasc Res 2012; 97:182-91. [DOI: 10.1093/cvr/cvs299] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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32
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Kaese S, Verheule S. Cardiac electrophysiology in mice: a matter of size. Front Physiol 2012; 3:345. [PMID: 22973235 PMCID: PMC3433738 DOI: 10.3389/fphys.2012.00345] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/09/2012] [Indexed: 12/27/2022] Open
Abstract
Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias.
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Affiliation(s)
- Sven Kaese
- Division of Experimental and Clinical Electrophysiology, Department of Cardiology and Angiology, University Hospital Münster Münster, Germany
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33
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Kim KH, Rosen A, Bruneau BG, Hui CC, Backx PH. Iroquois homeodomain transcription factors in heart development and function. Circ Res 2012; 110:1513-24. [PMID: 22628575 DOI: 10.1161/circresaha.112.265041] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Numerous cardiac transcription factors play overlapping roles in both the specification and proliferation of the cardiac tissues and chambers during heart development. It has become increasingly apparent that cardiac transcription factors also play critical roles in the regulation of expression of many functional genes in the prenatal and postnatal hearts. Accordingly, mutations of cardiac transcription factors cannot only result in congenital heart defects but also alter heart function thereby predisposing to heart disease and cardiac arrhythmias. In this review, we summarize the roles of Iroquois homeobox (Irx) family of transcription factors in heart development and function. In all, 6 Irx genes are expressed with distinct and overlapping patterns in the mammalian heart. Studies in several animal models demonstrate that Irx genes are important for the establishment of ventricular chamber properties, the ventricular conduction system, as well as heterogeneity of the ventricular repolarization. The molecular mechanisms by which Irx proteins regulate gene expression and the clinical relevance of Irx functions in the heart are discussed.
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Affiliation(s)
- Kyoung-Han Kim
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
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34
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Raveau M, Lignon JM, Nalesso V, Duchon A, Groner Y, Sharp AJ, Dembele D, Brault V, Hérault Y. The App-Runx1 region is critical for birth defects and electrocardiographic dysfunctions observed in a Down syndrome mouse model. PLoS Genet 2012; 8:e1002724. [PMID: 22693452 PMCID: PMC3364940 DOI: 10.1371/journal.pgen.1002724] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/05/2012] [Indexed: 01/24/2023] Open
Abstract
Down syndrome (DS) leads to complex phenotypes and is the main genetic cause of birth defects and heart diseases. The Ts65Dn DS mouse model is trisomic for the distal part of mouse chromosome 16 and displays similar features with post-natal lethality and cardiovascular defects. In order to better understand these defects, we defined electrocardiogram (ECG) with a precordial set-up, and we found conduction defects and modifications in wave shape, amplitudes, and durations in Ts65Dn mice. By using a genetic approach consisting of crossing Ts65Dn mice with Ms5Yah mice monosomic for the App-Runx1 genetic interval, we showed that the Ts65Dn viability and ECG were improved by this reduction of gene copy number. Whole-genome expression studies confirmed gene dosage effect in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah hearts and showed an overall perturbation of pathways connected to post-natal lethality (Coq7, Dyrk1a, F5, Gabpa, Hmgn1, Pde10a, Morc3, Slc5a3, and Vwf) and heart function (Tfb1m, Adam19, Slc8a1/Ncx1, and Rcan1). In addition cardiac connexins (Cx40, Cx43) and sodium channel sub-units (Scn5a, Scn1b, Scn10a) were found down-regulated in Ts65Dn atria with additional down-regulation of Cx40 in Ts65Dn ventricles and were likely contributing to conduction defects. All these data pinpoint new cardiac phenotypes in the Ts65Dn, mimicking aspects of human DS features and pathways altered in the mouse model. In addition they highlight the role of the App-Runx1 interval, including Sod1 and Tiam1, in the induction of post-natal lethality and of the cardiac conduction defects in Ts65Dn. These results might lead to new therapeutic strategies to improve the care of DS people.
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Affiliation(s)
- Matthieu Raveau
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Jacques M. Lignon
- Immunologie et Embryologie Moléculaire, CNRS Université d'Orléans, UMR6218, Orléans, France
| | - Valérie Nalesso
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Arnaud Duchon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Yoram Groner
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Andrew J. Sharp
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Doulaye Dembele
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Véronique Brault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, Illkirch, France
- Transgénèse et Archivage d'Animaux Modèles, CNRS, UPS44, Orléans, France
- Institut Clinique de la Souris, Illkirch, France
- * E-mail:
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35
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Martin CA, Matthews GDK, Huang CLH. Sudden cardiac death and inherited channelopathy: the basic electrophysiology of the myocyte and myocardium in ion channel disease. Heart 2012; 98:536-43. [PMID: 22422742 PMCID: PMC3308472 DOI: 10.1136/heartjnl-2011-300953] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mutations involving cardiac ion channels result in abnormal action potential formation or propagation, leading to cardiac arrhythmias. Despite the large impact on society of sudden cardiac death resulting from such arrhythmias, understanding of the underlying cellular mechanism is poor and clinical risk stratification and treatment consequently limited. Basic research using molecular techniques, as well as animal models, has proved extremely useful in improving our knowledge of inherited arrhythmogenic syndromes. This offers the practitioner tools to accurately diagnose rare disorders and provides novel markers for risk assessment and a basis for new strategies of treatment.
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Affiliation(s)
- Claire A Martin
- Physiological Laboratory, University of Cambridge, Cambridge CB2 3EG, UK.
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36
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Izumi D, Chinushi M, Iijima K, Furushima H, Hosaka Y, Hasegawa K, Aizawa Y. The peak-to-end of the T wave in the limb ECG leads reflects total spatial rather than transmural dispersion of ventricular repolarization in an anthopleurin-A model of prolonged QT interval. Heart Rhythm 2012; 9:796-803. [DOI: 10.1016/j.hrthm.2011.11.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Indexed: 11/29/2022]
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37
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Brisinda D, Sorbo AR, Venuti A, Fenici R. Percutaneous method for single-catheter multiple monophasic action potential recordings during magnetocardiographic mapping in spontaneously breathing rodents. Physiol Meas 2012; 33:521-34. [PMID: 22373565 DOI: 10.1088/0967-3334/33/3/521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To test the feasibility of a novel method to combine magnetocardiographic (MCG) estimate of ventricular repolarization (VR) and multiple monophasic action potential (MultiMAP) recording in spontaneously breathing rodents with percutaneous sub-xyphoid epicardial placement of a MCG-compatible amagnetic catheter (AC), ten Wistar rats (WRs) and ten guinea pigs (GPs) were studied. Under fluoroscopic control, the AC was moved until four stable MAPs were recorded (fixed inter-electrode distance of 1.2 mm). 36-channel DC-SQUID (sensitivity 20 fT Hz(-½)) were used for MCG mapping. MAPs, differentially amplified (BW: DC-500 Hz), were digitized at 1 kHz. AC pacing provided local ventricular effective refractory period (VERP) estimate. MAP duration (MAPd) was measured at 50% and 90% levels of repolarization. Simultaneous MCG mapping and MultiMAP recording were successful in all animals. Average MAPd50% and MAPd90% were shorter in WRs than in GPs (26.4 ± 2.9 ms versus 110.6 ± 14.3 ms and 60.7 ± 5.4 ms versus 127.7 ± 15.3 ms, respectively). VERP was 51 ± 4.8 ms in WRs and 108.4 ± 12.9 ms in GPs, respectively. The MAP amplitude was 16.9 ± 4.5 in WRs and 16.2 ± 4.2 in GPs. MAP and MCG parameters of VR were in good agreement. All animals survived the procedure. Two also survived a second invasive study; one was followed up until natural death at 52 months. Percutaneous MultiMAP recording is minimally invasive, usually avoids animal sacrifice, is compatible with simultaneous surface MCG mapping and might be used for experimental validation of MCG VR abnormality, to study the arrhythmogenic potential of new drugs and/or animal models of ventricular arrhythmias.
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Affiliation(s)
- Donatella Brisinda
- Clinical Physiology-Biomagnetism Center, Catholic University of Sacred Heart, Rome, Italy
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38
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Ferreiro M, Petrosky AD, Escobar AL. Intracellular Ca2+ release underlies the development of phase 2 in mouse ventricular action potentials. Am J Physiol Heart Circ Physiol 2011; 302:H1160-72. [PMID: 22198177 DOI: 10.1152/ajpheart.00524.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ventricular action potential (AP) is characterized by a fast depolarizing phase followed by a repolarization that displays a second upstroke known as phase 2. This phase is generally not present in mouse ventricular myocytes. Thus we performed colocalized electrophysiological and optical recordings of APs in Langendorff-perfused mouse hearts founding a noticeable phase 2. Ryanodine as well as nifedipine reduced phase 2. Our hypothesis is that a depolarizing current activated by Ca(2+) released from the sarcoplasmic reticulum (SR) rather than the "electrogenicity" of the L-type Ca(2+) current is crucial in the generation of mouse ventricular phase 2. When Na(+) was partially replaced by Li(+) in the extracellular perfusate or the organ was cooled down, phase 2 was reduced. These results suggest that the Na(+)/Ca(2+) exchanger functioning in the forward mode is driving the depolarizing current that defines phase 2. Phase 2 appears to be an intrinsic characteristic of single isolated myocytes and not an emergent property of the tissue. As in whole heart experiments, ventricular myocytes impaled with microelectrodes displayed a large phase 2 that significantly increases when temperature was raised from 22 to 37°C. We conclude that mouse ventricular APs display a phase 2; however, changes in Ca(2+) dynamics and thermodynamic parameters also diminish phase 2, mostly by impairing the Na(+)/Ca(2+) exchanger. In summary, these results provide important insights about the role of Ca(2+) release in AP ventricular repolarization under physiological and pathological conditions.
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Affiliation(s)
- Marcela Ferreiro
- Biological Engineering and Small Scale Technologies Program, School of Engineering, University of California, Merced, CA 95343, USA
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39
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Characterization of the failing murine heart in a desmin knock-out model using a clinical 3 T MRI scanner. Int J Cardiovasc Imaging 2011; 28:1699-705. [DOI: 10.1007/s10554-011-9990-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 11/28/2011] [Indexed: 11/26/2022]
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40
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Li Z, Liu Y, Hertervig E, Kongstad O, Yuan S. Regional heterogeneity of right atrial repolarization. Monophasic action potential mapping in swine. SCAND CARDIOVASC J 2011; 45:336-41. [DOI: 10.3109/14017431.2011.597870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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41
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Kobayashi T, Ito T, Shiomi M. Roles of the WHHL rabbit in translational research on hypercholesterolemia and cardiovascular diseases. J Biomed Biotechnol 2011; 2011:406473. [PMID: 21541231 PMCID: PMC3085394 DOI: 10.1155/2011/406473] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 01/17/2011] [Accepted: 02/15/2011] [Indexed: 02/02/2023] Open
Abstract
Conquering cardiovascular diseases is one of the most important problems in human health. To overcome cardiovascular diseases, animal models have played important roles. Although the prevalence of genetically modified animals, particularly mice and rats, has contributed greatly to biomedical research, not all human diseases can be investigated in this way. In the study of cardiovascular diseases, mice and rats are inappropriate because of marked differences in lipoprotein metabolism, pathophysiological findings of atherosclerosis, and cardiac function. On the other hand, since lipoprotein metabolism and atherosclerotic lesions in rabbits closely resemble those in humans, several useful animal models for these diseases have been developed in rabbits. One of the most famous of these is the Watanabe heritable hyperlipidemic (WHHL) rabbit, which develops hypercholesterolemia and atherosclerosis spontaneously due to genetic and functional deficiencies of the low-density lipoprotein (LDL) receptor. The WHHL rabbit has been improved to develop myocardial infarction, and the new strain was designated the myocardial infarction-prone WHHL (WHHLMI) rabbit. This review summarizes the importance of selecting animal species for translational research in biomedical science, the development of WHHL and WHHLMI rabbits, their application to the development of hypocholesterolemic and/or antiatherosclerotic drugs, and future prospects regarding WHHL and WHHLMI rabbits.
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Affiliation(s)
- Tsutomu Kobayashi
- Institute for Experimental Animals, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Takashi Ito
- Institute for Experimental Animals, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Masashi Shiomi
- Institute for Experimental Animals, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
- Section of Animal Models for Cardiovascular Disease, Division of Cardiovascular Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
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Kalin A, Usher-Smith J, Jones VJ, Huang CLH, Sabir IN. Cardiac arrhythmia: a simple conceptual framework. Trends Cardiovasc Med 2011; 20:103-7. [PMID: 21130954 DOI: 10.1016/j.tcm.2010.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/31/2010] [Indexed: 10/18/2022]
Abstract
This review presents a simple trigger-substrate model of arrhythmogenesis and its application to the generation of reentrant ventricular arrhythmias. We demonstrate its broad applicability to the understanding of arrhythmic phenomena in a wide range of both hereditary and acquired arrhythmic disorders.
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Affiliation(s)
- Asli Kalin
- John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
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Heterogeneity of apex-to-base dispersion in diastolic lengthening is related to impaired global left ventricular relaxation in patients with hypertrophic cardiomyopathy. J Echocardiogr 2010; 9:9-16. [PMID: 27279089 DOI: 10.1007/s12574-010-0059-4] [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: 04/26/2010] [Revised: 06/30/2010] [Accepted: 07/01/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND The presence of apex-to-base disparity in diastolic left ventricle (LV) endocardial lengthening, based on an electromechanical activation sequence, has been recognized as an important determinant of LV diastolic properties. However, the behavior of LV apical and basal diastolic lengthening and its relationship to LV filling in hypertrophic cardiomyopathy (HCM) are unknown. METHODS We obtained basal and apical LV short-axis views in 27 patients with non-obstructive HCM and 25 healthy volunteers. The patients with HCM were subdivided into two groups; those with apical hypertrophy [APH(+)] or those without apical hypertrophy [APH(-)]. Eight equiangular points on the endo-myocardium at end diastole were placed in each view, and the movements of these points were automatically tracked using a two-dimensional echocardiographic tissue tracking system. Time-LV internal diameter curves were obtained and averaged. The time intervals from the aortic valve closure to the point of the first 40% of peak diastolic lengthening (T 40) were measured in each view. The standard deviation of the time to peak systolic circumferential shortening at the base and apex were calculated to assess the heterogeneity of LV contraction. RESULTS The time difference in the T 40 between the apex and base (dt-T 40) in the HCM-APH(+) and HCM-APH(-) groups was greater than that in the control group. The heterogeneities in LV apical systolic shortening in the HCM groups were greater than those in the control group. There were good linear correlations between the dt-T 40 and the LV early diastolic echo-parameters and the LV mass index. CONCLUSIONS Delayed apical relaxation and filling in patients with HCM is related to LV diastolic dysfunction and systolic dyssynchronous contraction.
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Leong IUS, Skinner JR, Shelling AN, Love DR. Zebrafish as a model for long QT syndrome: the evidence and the means of manipulating zebrafish gene expression. Acta Physiol (Oxf) 2010; 199:257-76. [PMID: 20331541 DOI: 10.1111/j.1748-1716.2010.02111.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Congenital long QT syndrome (LQT) is a group of cardiac disorders associated with the dysfunction of cardiac ion channels. It is characterized by prolongation of the QT-interval, episodes of syncope and even sudden death. Individuals may remain asymptomatic for most of their lives while others present with severe symptoms. This heterogeneity in phenotype makes diagnosis difficult with a greater emphasis on more targeted therapy. As a means of understanding the molecular mechanisms underlying LQT syndrome, evaluating the effect of modifier genes on disease severity as well as to test new therapies, the development of model systems remains an important research tool. Mice have predominantly been the animal model of choice for cardiac arrhythmia research, but there have been varying degrees of success in recapitulating the human symptoms; the mouse cardiac action potential (AP) and surface electrocardiograms exhibit major differences from those of the human heart. Against this background, the zebrafish is an emerging vertebrate disease modelling species that offers advantages in analysing LQT syndrome, not least because its cardiac AP much more closely resembles that of the human. This article highlights the use and potential of this species in LQT syndrome modelling, and as a platform for the in vivo assessment of putative disease-causing mutations in LQT genes, and of therapeutic interventions.
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45
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Kaiser L, Davis JM, Patterson J, Johnson AL, Bohart G, Olivier NB, Schwartz KA. Iron sufficient to cause hepatic fibrosis and ascites does not cause cardiac arrhythmias in the gerbil. Transl Res 2009; 154:202-13. [PMID: 19766964 DOI: 10.1016/j.trsl.2009.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 07/08/2009] [Accepted: 07/09/2009] [Indexed: 01/13/2023]
Abstract
Chronic iron overload associated with hereditary hemochromatosis or repeated red cell transfusions is known to cause cardiac failure. Cardiac arrhythmias have been incidentally noted in patients with iron overload, but they are often dismissed as being related to comorbid conditions. Studies with anesthetized iron-loaded gerbils using short recordings suggest a role for iron in the development of arrhythmias. Our goal was to characterize iron-induced arrhythmias in the chronically instrumented, untethered, telemetered gerbil. Electrocardiograms were recorded for 10 s every 30 min for approximately 6 months in iron-loaded (n=23) and control (n=8) gerbils. All gerbils in both groups showed evidence of frequent sinus arrhythmia. There was no difference in heart rate, electrocardiographic parameters, or number of arrhythmias per minute between groups. Gerbils rarely showed significant arrhythmias. Body weight and heart weight were not significantly different between groups, whereas liver weight increased with increasing iron dose in the treated group. Cardiac and hepatic iron concentrations were significantly increased in iron-loaded gerbils. Eight of 14 gerbils loaded to 6.2 g/kg body weight developed ascites. We conclude that an iron load sufficient to cause clinical liver disease does not cause cardiac arrhythmias in the gerbil model of iron overload.
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Affiliation(s)
- Lana Kaiser
- Hematology & Oncology Unit, Department of Medicine, College of Human Medicine, Michigan State University, East Lansing, MI, USA.
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46
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Weber dos Santos R, Nygren A, Otaviano Campos F, Koch H, Giles WR. Experimental and theoretical ventricular electrograms and their relation to electrophysiological gradients in the adult rat heart. Am J Physiol Heart Circ Physiol 2009; 297:H1521-34. [DOI: 10.1152/ajpheart.01066.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The electrical activity of adult mouse and rat hearts has been analyzed extensively, often as a prerequisite for genetic engineering studies or for the development of rodent models of human diseases. Some aspects of the initiation and conduction of the cardiac action potential in rodents closely resemble those in large mammals. However, rodents have a much higher heart rate and their ventricular action potential is triangular and very short. As a consequence, an interpretation of the electrocardiogram in the mouse and rat remains difficult and controversial. In this study, optical mapping techniques have been applied to an in vitro left ventricular adult rat preparation to obtain patterns of conduction and action potential duration measurements from the epicardial surface. This information has been combined with previously published mathematical models of the rat ventricular myocyte to develop a bidomain model for action potential propagation and electrogram formation in the rat left ventricle. Important insights into the basis for the repolarization waveform in the ventricular electrogram of the adult rat have been obtained. Notably, our model demonstrated that the biphasic shape of the rat ventricular repolarization wave can be explained in terms of the transmural and apex-to-base gradients in action potential duration that exist in the rat left ventricle.
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Affiliation(s)
| | - Anders Nygren
- Department of Physiology and Biophysics,
- Department of Electrical and Computer Engineering,
- Centre for Bioengineering Research and Education, and
| | - Fernando Otaviano Campos
- Department of Computer Science, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
- Institute of Biophysics, Medical University of Graz, Graz, Austria; and
| | - Hans Koch
- Department of Biosignals, Physikalisch-Technische Bundesanstalt, Berlin, Germany
| | - Wayne R. Giles
- Department of Physiology and Biophysics,
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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47
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Stables CL, Curtis MJ. Development and characterization of a mouse in vitro model of ischaemia-induced ventricular fibrillation. Cardiovasc Res 2009; 83:397-404. [DOI: 10.1093/cvr/cvp068] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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48
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Huggins CE, Bell JR, Pepe S, Delbridge LM. Benchmarking Ventricular Arrhythmias in the Mouse—Revisiting the ‘Lambeth Conventions’ 20 Years On. Heart Lung Circ 2008; 17:445-50. [DOI: 10.1016/j.hlc.2008.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Accepted: 08/12/2008] [Indexed: 10/21/2022]
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49
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Dispersions of repolarization and ventricular arrhythmogenesis: Lessons from animal models. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 98:219-29. [DOI: 10.1016/j.pbiomolbio.2008.10.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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50
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Sabir IN, Killeen MJ, Grace AA, Huang CLH. Ventricular arrhythmogenesis: Insights from murine models. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 98:208-18. [DOI: 10.1016/j.pbiomolbio.2008.10.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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