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Jones D, Hartung J, Lasalle E, Borquez A, Murillo V, Guidugli L, James KN, Kingsmore SF, Coufal NG. Novel variants in TECRL leading to catecholaminergic polymorphic ventricular tachycardia. Life Sci Alliance 2024; 7:e202402572. [PMID: 38777371 PMCID: PMC11111969 DOI: 10.26508/lsa.202402572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Pathogenic and likely pathogenic variants in the TECRL gene are known to be associated with recessive catecholaminergic polymorphic ventricular tachycardia 3, which can include prolonged QT intervals (MIM#614021). We report a case of cardiac arrest in a previously healthy adolescent male in the community. The patient was found to have a novel maternally inherited likely pathogenic variant in TECRL (c.915T>G [p.Tyr305Ter]) and an additional 19-kb duplication encompassing multiple exons of TECRL (chr4:65165944-65185287, dup [4q13.1]) not identified in the mother. Genetic results were revealed via rapid whole-genome sequencing, which allowed appropriate treatment and prognostication.
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Affiliation(s)
- Douglas Jones
- Rady Children's Hospital, San Diego, CA, USA
- https://ror.org/0168r3w48 Division of Pediatric Critical Care, Department of Pediatrics, University of California, San Diego, CA, USA
| | - Jacob Hartung
- Rady Children's Hospital, San Diego, CA, USA
- https://ror.org/0168r3w48 Division of Pediatric Critical Care, Department of Pediatrics, University of California, San Diego, CA, USA
| | - Elizabeth Lasalle
- Rady Children's Hospital, San Diego, CA, USA
- https://ror.org/0168r3w48 Division of Cardiology, Department of Pediatrics, University of California, San Diego, CA, USA
| | - Alejandro Borquez
- Rady Children's Hospital, San Diego, CA, USA
- https://ror.org/0168r3w48 Division of Cardiology, Department of Pediatrics, University of California, San Diego, CA, USA
| | | | - Lucia Guidugli
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Kiely N James
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | | | - Nicole G Coufal
- Rady Children's Hospital, San Diego, CA, USA
- https://ror.org/0168r3w48 Division of Pediatric Critical Care, Department of Pediatrics, University of California, San Diego, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
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2
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Lei M, Salvage SC, Jackson AP, Huang CLH. Cardiac arrhythmogenesis: roles of ion channels and their functional modification. Front Physiol 2024; 15:1342761. [PMID: 38505707 PMCID: PMC10949183 DOI: 10.3389/fphys.2024.1342761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/22/2024] [Indexed: 03/21/2024] Open
Abstract
Cardiac arrhythmias cause significant morbidity and mortality and pose a major public health problem. They arise from disruptions in the normally orderly propagation of cardiac electrophysiological activation and recovery through successive cardiomyocytes in the heart. They reflect abnormalities in automaticity, initiation, conduction, or recovery in cardiomyocyte excitation. The latter properties are dependent on surface membrane electrophysiological mechanisms underlying the cardiac action potential. Their disruption results from spatial or temporal instabilities and heterogeneities in the generation and propagation of cellular excitation. These arise from abnormal function in their underlying surface membrane, ion channels, and transporters, as well as the interactions between them. The latter, in turn, form common regulatory targets for the hierarchical network of diverse signaling mechanisms reviewed here. In addition to direct molecular-level pharmacological or physiological actions on these surface membrane biomolecules, accessory, adhesion, signal transduction, and cytoskeletal anchoring proteins modify both their properties and localization. At the cellular level of excitation-contraction coupling processes, Ca2+ homeostatic and phosphorylation processes affect channel activity and membrane excitability directly or through intermediate signaling. Systems-level autonomic cellular signaling exerts both acute channel and longer-term actions on channel expression. Further upstream intermediaries from metabolic changes modulate the channels both themselves and through modifying Ca2+ homeostasis. Finally, longer-term organ-level inflammatory and structural changes, such as fibrotic and hypertrophic remodeling, similarly can influence all these physiological processes with potential pro-arrhythmic consequences. These normal physiological processes may target either individual or groups of ionic channel species and alter with particular pathological conditions. They are also potentially alterable by direct pharmacological action, or effects on longer-term targets modifying protein or cofactor structure, expression, or localization. Their participating specific biomolecules, often clarified in experimental genetically modified models, thus constitute potential therapeutic targets. The insights clarified by the physiological and pharmacological framework outlined here provide a basis for a recent modernized drug classification. Together, they offer a translational framework for current drug understanding. This would facilitate future mechanistically directed therapeutic advances, for which a number of examples are considered here. The latter are potentially useful for treating cardiac, in particular arrhythmic, disease.
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Affiliation(s)
- Ming Lei
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Samantha C. Salvage
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Antony P. Jackson
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christopher L.-H. Huang
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
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3
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Burashnikov A, Di Diego JM, Patocskai B, Echt DS, Belardinelli L, Antzelevitch C. Effect of Flecainide and Ibutilide Alone and in Combination to Terminate and Prevent Recurrence of Atrial Fibrillation. Circ Arrhythm Electrophysiol 2024; 17:e012454. [PMID: 38146652 DOI: 10.1161/circep.123.012454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/30/2023] [Indexed: 12/27/2023]
Abstract
BACKGROUND There is a need for improved approaches to rhythm control therapy of atrial fibrillation (AF). METHODS The effectiveness of flecainide (1.5 µmol/L) and ibutilide (20 nmol/L), alone and in combination, to cardiovert and prevent AF recurrence was studied in canine-isolated coronary-perfused right atrioventricular preparations. We also examined the safety of the combination of flecainide (1.5 µmol/L) and ibutilide (50 nmol/L) using canine left ventricular wedge preparations. RESULTS Sustained AF (>1 hour) was inducible in 100%, 60%, 20%, and 0% of atria in the presence of acetylcholine alone, acetylcholine+ibutilide, acetylcholine+flecainide, and acetylcholine+ibutilide+flecainide, respectively. When used alone, flecainide and ibutilide cardioverted sustained AF in 40% and 20% of atria, respectively, but in 100% of atria when used in combination. Ibutilide prolonged atrial and ventricular effective refractory period by 15% and 8%, respectively, at a cycle length of 500 ms (P<0.05 for both). Flecainide increased the effective refractory period in atria by 27% (P<0.01) but by only 2% in the ventricles. The combination of the 2 drugs lengthened the effective refractory period by 42% in atria (P<0.01) but by only 7% (P<0.05) in the ventricles. In left ventricular wedges, ibutilide prolonged QT and Tpeak-Tend intervals by 25 and 55%, respectively (P<0.05 for both; cycle length, 2000 ms). The addition of flecainide (1.5 µmol/L) partially reversed these effects (P<0.05 for both parameters versus ibutilide alone). Torsades de Pointes score was relatively high with ibutilide alone and low with the drug combination. CONCLUSIONS In our experimental model, a combination of flecainide and ibutilide significantly improves cardioversion and prevents the recurrence of AF compared with monotherapies with little to no risk for the development of long-QT-mediated ventricular proarrhythmia.
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Affiliation(s)
- Alexander Burashnikov
- Lankenau Institute for Medical Research, Wynnewood, PA (A.B., J.M.D.D., B.P., C.A.)
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA (A.B., C.A.)
| | - José M Di Diego
- Lankenau Institute for Medical Research, Wynnewood, PA (A.B., J.M.D.D., B.P., C.A.)
| | - Bence Patocskai
- Lankenau Institute for Medical Research, Wynnewood, PA (A.B., J.M.D.D., B.P., C.A.)
| | - Debra S Echt
- InCarda Therapeutics, Inc, Newark, CA (D.S.E., L.B.)
| | | | - Charles Antzelevitch
- Lankenau Institute for Medical Research, Wynnewood, PA (A.B., J.M.D.D., B.P., C.A.)
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA (A.B., C.A.)
- Lankenau Heart Institute, Main Line Health System, Wynnewood, PA (C.A.)
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Davidson R, Medeiros M. Insights on the mechanism of flecainide in catecholaminergic polymorphic ventricular tachycardia. J Med Life 2023; 16:1294-1296. [PMID: 38024821 PMCID: PMC10652680 DOI: 10.25122/jml-2023-0191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/11/2023] [Indexed: 12/01/2023] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by defective cardiac ryanodine receptor (RyR2) calcium release during times of adrenergic stimulation, resulting in bidirectional or polymorphic ventricular tachycardia. Flecainide is a class 1c anti-arrhythmic drug that has demonstrated therapeutic efficacy in treating CPVT. However, its mechanism of action remains disputed. One group proposes a direct effect of flecainide on RyR2-mediated calcium release, while another proposes an indirect effect via sodium channel blockade and modulation of intracellular calcium dynamics. In light of recent studies, this commentary aims to explore and discuss the evidence base for these potential mechanisms.
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Affiliation(s)
- Ross Davidson
- Department of Medicine, King’s College Hospital, Denmark Hill, London
| | - Maria Medeiros
- Department of Medicine, King’s College Hospital, Denmark Hill, London
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Voigt N, Seibertz F, Fakuade FE. Vicious Twins: RyR2 Dysfunction and Structural Remodeling. Circ Res 2023; 133:193-195. [PMID: 37410856 DOI: 10.1161/circresaha.123.323144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Affiliation(s)
- Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg August University Göttingen, Germany (N.V., F.S., F.E.F.)
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (N.V., F.S., F.E.F.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (N.V., F.S., F.E.F.)
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg August University Göttingen, Germany (N.V., F.S., F.E.F.)
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (N.V., F.S., F.E.F.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (N.V., F.S., F.E.F.)
| | - Funsho E Fakuade
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg August University Göttingen, Germany (N.V., F.S., F.E.F.)
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (N.V., F.S., F.E.F.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (N.V., F.S., F.E.F.)
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6
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Zhang X, Smith CER, Morotti S, Edwards AG, Sato D, Louch WE, Ni H, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: II. Ca 2+ -handling protein variation. J Physiol 2023; 601:2685-2710. [PMID: 36114707 PMCID: PMC10017376 DOI: 10.1113/jp283602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Disruption of the transverse-axial tubule system (TATS) in diseases such as heart failure and atrial fibrillation occurs in combination with changes in the expression and distribution of key Ca2+ -handling proteins. Together this ultrastructural and ionic remodelling is associated with aberrant Ca2+ cycling and electrophysiological instabilities that underlie arrhythmic activity. However, due to the concurrent changes in TATs and Ca2+ -handling protein expression and localization that occur in disease it is difficult to distinguish their individual contributions to the arrhythmogenic state. To investigate this, we applied our novel 3D human atrial myocyte model with spatially detailed Ca2+ diffusion and TATS to investigate the isolated and interactive effects of changes in expression and localization of key Ca2+ -handling proteins and variable TATS density on Ca2+ -handling abnormality driven membrane instabilities. We show that modulating the expression and distribution of the sodium-calcium exchanger, ryanodine receptors and the sarcoplasmic reticulum (SR) Ca2+ buffer calsequestrin have varying pro- and anti-arrhythmic effects depending on the balance of opposing influences on SR Ca2+ leak-load and Ca2+ -voltage relationships. Interestingly, the impact of protein remodelling on Ca2+ -driven proarrhythmic behaviour varied dramatically depending on TATS density, with intermediately tubulated cells being more severely affected compared to detubulated and densely tubulated myocytes. This work provides novel mechanistic insight into the distinct and interactive consequences of TATS and Ca2+ -handling protein remodelling that underlies dysfunctional Ca2+ cycling and electrophysiological instability in disease. KEY POINTS: In our companion paper we developed a 3D human atrial myocyte model, coupling electrophysiology and Ca2+ handling with subcellular spatial details governed by the transverse-axial tubule system (TATS). Here we utilize this model to mechanistically examine the impact of TATS loss and changes in the expression and distribution of key Ca2+ -handling proteins known to be remodelled in disease on Ca2+ homeostasis and electrophysiological stability. We demonstrate that varying the expression and localization of these proteins has variable pro- and anti-arrhythmic effects with outcomes displaying dependence on TATS density. Whereas detubulated myocytes typically appear unaffected and densely tubulated cells seem protected, the arrhythmogenic effects of Ca2+ handling protein remodelling are profound in intermediately tubulated cells. Our work shows the interaction between TATS and Ca2+ -handling protein remodelling that underlies the Ca2+ -driven proarrhythmic behaviour observed in atrial fibrillation and may help to predict the effects of antiarrhythmic strategies at varying stages of ultrastructural remodelling.
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Affiliation(s)
- Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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7
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Gaine SP, Calkins H. Antiarrhythmic Drug Therapy in Arrhythmogenic Right Ventricular Cardiomyopathy. Biomedicines 2023; 11:biomedicines11041213. [PMID: 37189831 DOI: 10.3390/biomedicines11041213] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/07/2023] [Accepted: 04/12/2023] [Indexed: 05/17/2023] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable progressive myocardial disorder that predisposes patients to ventricular arrhythmias and sudden cardiac death. Antiarrhythmic medications have an important role in reducing the frequency of ventricular arrhythmias and the morbidity associated with recurrent implantable cardioverter-defibrillator (ICD) shocks. Although several studies have examined the use of antiarrhythmic drugs in ARVC, these have been mostly retrospective in nature and inconsistent in their methodology, patient population and endpoints. Thus, current prescribing practices are largely based on expert opinion and extrapolation from other diseases. Herein, we discuss the major studies of the use of antiarrhythmics in ARVC, present the current approach employed at the Johns Hopkins Hospital and identify areas where further research is needed. Most notably, there is a great need for high-quality studies with consistent methodology and randomized controlled trial data into the use of antiarrhythmic drugs in ARVC. This would improve management of the condition and ensure antiarrhythmic prescribing is based on robust evidence.
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Affiliation(s)
- Sean P Gaine
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Hugh Calkins
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- The Hugh Calkins, Marvin H. Weiner and Jacque J. Bernstein Cardiac Arrhythmia Center, Department of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Jin X, Meletiou A, Chung J, Tilunaite A, Demydenko K, Dries E, Puertas RD, Amoni M, Tomar A, Claus P, Soeller C, Rajagopal V, Sipido K, Roderick HL. InsP 3R-RyR channel crosstalk augments sarcoplasmic reticulum Ca 2+ release and arrhythmogenic activity in post-MI pig cardiomyocytes. J Mol Cell Cardiol 2023; 179:47-59. [PMID: 37003353 DOI: 10.1016/j.yjmcc.2023.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 03/08/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Ca2+ transients (CaT) underlying cardiomyocyte (CM) contraction require efficient Ca2+ coupling between sarcolemmal Ca2+ channels and sarcoplasmic reticulum (SR) ryanodine receptor Ca2+ channels (RyR) for their generation; reduced coupling in disease contributes to diminished CaT and arrhythmogenic Ca2+ events. SR Ca2+ release also occurs via inositol 1,4,5-trisphosphate receptors (InsP3R) in CM. While this pathway contributes negligeably to Ca2+ handling in healthy CM, rodent studies support a role in altered Ca2+ dynamics and arrhythmogenic Ca2+ release involving InsP3R crosstalk with RyRs in disease. Whether this mechanism persists in larger mammals with lower T-tubular density and coupling of RyRs is not fully resolved. We have recently shown an arrhythmogenic action of InsP3-induced Ca2+ release (IICR) in end stage human heart failure, often associated with underlying ischemic heart disease (IHD). How IICR contributes to early stages of disease is however not determined but highly relevant. To access this stage, we chose a porcine model of IHD, which shows substantial remodelling of the area adjacent to the infarct. In cells from this region, IICR preferentially augmented Ca2+ release from non-coupled RyR clusters that otherwise showed delayed activation during the CaT. IICR in turn synchronised Ca2+ release during the CaT but also induced arrhythmogenic delayed afterdepolarizations and action potentials. Nanoscale imaging identified co-clustering of InsP3Rs and RyRs, thereby allowing Ca2+-mediated channel crosstalk. Mathematical modelling supported and further delineated this mechanism of enhanced InsP3R-RyRs coupling in MI. Our findings highlight the role of InsP3R-RyR channel crosstalk in Ca2+ release and arrhythmia during post-MI remodelling.
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Affiliation(s)
- Xin Jin
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - Anna Meletiou
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Joshua Chung
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium; Cell Structure and Mechanobiology Group, Department of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Australia
| | - Agne Tilunaite
- Cell Structure and Mechanobiology Group, Department of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Australia; Systems Biology Laboratory, School of Mathematics and Statistics, and Department of Biomedical Engineering, University of Melbourne, Australia
| | - Kateryna Demydenko
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - Eef Dries
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - Rosa Doñate Puertas
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - Matthew Amoni
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - Ashutosh Tomar
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - Piet Claus
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | | | - Vijay Rajagopal
- Cell Structure and Mechanobiology Group, Department of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Australia
| | - Karin Sipido
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium
| | - H Llewelyn Roderick
- KU Leuven, Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, B-3000 Leuven, Belgium.
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9
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Iyer KA, Barnakov V, Samsó M. Three-dimensional perspective on ryanodine receptor mutations causing skeletal and cardiac muscle-related diseases. Curr Opin Pharmacol 2023; 68:102327. [PMID: 36516687 PMCID: PMC9908851 DOI: 10.1016/j.coph.2022.102327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 12/14/2022]
Abstract
Mutations in RyR alter the cell's Ca2+ homeostasis and can cause serious health problems for which few effective therapies are available. Until recently, there was little structural context for the hundreds of mutations linked to muscular disorders reported for this large channel. Growing knowledge of the three-dimensional structure of RyR starts to illustrate the fine control of Ca2+ release. Current efforts directed towards understanding how disease mutations impinge in such processes will be crucial for future design of novel therapies. In this review article we discuss the up-to-date information about mutations according to their role in the 3D structure, and classified them to provide context from a structural perspective.
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Affiliation(s)
- Kavita A Iyer
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Vadim Barnakov
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Montserrat Samsó
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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10
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Donniacuo M, De Angelis A, Telesca M, Bellocchio G, Riemma MA, Paolisso P, Scisciola L, Cianflone E, Torella D, Castaldo G, Capuano A, Urbanek K, Berrino L, Rossi F, Cappetta D. Atrial fibrillation: Epigenetic aspects and role of sodium-glucose cotransporter 2 inhibitors. Pharmacol Res 2023; 188:106591. [PMID: 36502999 DOI: 10.1016/j.phrs.2022.106591] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022]
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmia and is associated with substantial morbidity and mortality. Pathophysiological aspects consist in the activation of pro-fibrotic signaling and Ca2+ handling abnormalities at atrial level. Structural and electrical remodeling creates a substrate for AF by triggering conduction abnormalities and cardiac arrhythmias. The care of AF patients focuses predominantly on anticoagulation, symptoms control and the management of risk factors and comorbidities. The goal of AF therapy points to restore sinus rhythm, re-establish atrioventricular synchrony and improve atrial contribution to the stroke volume. New layer of information to better comprehend AF pathophysiology, and identify targets for novel pharmacological interventions consists of the epigenetic phenomena including, among others, DNA methylation, histone modifications and noncoding RNAs. Moreover, the benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in diabetic and non-diabetic patients at cardiovascular risk as well as emerging evidence on the ability of SGLT2i to modify epigenetic signature in cardiovascular diseases provide a solid background to investigate a possible role of this drug class in the onset and progression of AF. In this review, following a summary of pathophysiology and management, epigenetic mechanisms in AF and the potential of sodium-glucose SGLT2i in AF patients are discussed.
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Affiliation(s)
- M Donniacuo
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - A De Angelis
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - M Telesca
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - G Bellocchio
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - M A Riemma
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - P Paolisso
- Cardiovascular Center Aalst, OLV Hospital, Aalst, Belgium; Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via A. Pansini 5, 80131 Naples, Italy
| | - L Scisciola
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - E Cianflone
- Department of Medical and Surgical Sciences, Magna Graecia University, Viale Europa, 88100 Catanzaro, Italy
| | - D Torella
- Department of Experimental and Clinical Medicine, Magna Graecia University, Viale Europa, 88100 Catanzaro, Italy
| | - G Castaldo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples "Federico II", Via A. Pansini 5, 80131 Naples, Italy; CEINGE-Advanced, Via G. Salvatore 486, 80131 Naples, Italy
| | - A Capuano
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - K Urbanek
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples "Federico II", Via A. Pansini 5, 80131 Naples, Italy; CEINGE-Advanced, Via G. Salvatore 486, 80131 Naples, Italy.
| | - L Berrino
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - F Rossi
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - D Cappetta
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
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11
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Steer EJ, Yang Z, Al-Owais MM, Kirton HM, White E, Steele DS. Flecainide induces a sustained countercurrent dependent effect on RyR2 in permeabilized WT ventricular myocytes but not in intact cells. Front Pharmacol 2023; 14:1155601. [PMID: 37124209 PMCID: PMC10130871 DOI: 10.3389/fphar.2023.1155601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/29/2023] [Indexed: 05/02/2023] Open
Abstract
Background and purpose: While flecainide is now an accepted treatment for arrhythmias associated with catecholaminergic polymorphic ventricular tachycardia (CPVT), its mechanism of action remains controversial. In studies on myocytes from CPVT mice, inhibition of proarrhythmic Ca2+ waves was initially attributed to a novel action on the type-2 ryanodine receptor (RyR2). However, subsequent work on wild type (WT) myocytes questioned the conclusion that flecainide has a direct action on RyR2. In the present study, the effects of flecainide were compared in intact and permeabilized WT myocytes. Experimental approach: Intracellular Ca2+ was measured using confocal microscopy in intact or saponin permeabilized adult rat ventricular myocytes (ARVM). In some experiments on permeabilized cells, flecainide was studied following partial inhibition of the sarcoplasmic reticulum (SR) counter-current. Key results: Flecainide induced sustained changes Ca2+ sparks and waves in permeabilized ARVM, which were comparable to those reported in intact or permeabilized myocytes from CPVT mice. However, a relatively high level of flecainide (25 μM) was required to induce these effects. Inhibition of the SR counter-current potentiated the effects of flecainide on SR Ca2+ waves. In intact field stimulated ARVM, prolonged exposure to 15 μM flecainide decreased wave frequency but RyR2 dependent effects on Ca2+ sparks were absent; higher drug concentrations blocked field stimulation, consistent with inhibition of Nav1.5. Conclusions and implications: In intact ARVM, the absence of effects on Ca2+ sparks suggests that the intracellular flecainide concentration was insufficient to influence RyR2. Wave inhibition in intact ARVM may reflect secondary effects of Nav1.5 inhibition. Potentiation of flecainide's action by counter-current inhibition can be explained if transient polarization of the SR membrane during SR Ca2+ release facilitates its action on RyR2.
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McCoy MD, Ullah A, Lederer WJ, Jafri MS. Understanding Calmodulin Variants Affecting Calcium-Dependent Inactivation of L-Type Calcium Channels through Whole-Cell Simulation of the Cardiac Ventricular Myocyte. Biomolecules 2022; 13:72. [PMID: 36671457 PMCID: PMC9855640 DOI: 10.3390/biom13010072] [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: 11/09/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
Mutations in the calcium-sensing protein calmodulin (CaM) have been linked to two cardiac arrhythmia diseases, Long QT Syndrome 14 (LQT14) and Catecholaminergic Polymorphic Ventricular Tachycardia Type 4 (CPVT4), with varying degrees of severity. Functional characterization of the CaM mutants most strongly associated with LQT14 show a clear disruption of the calcium-dependent inactivation (CDI) of the L-Type calcium channel (LCC). CPVT4 mutants on the other hand are associated with changes in their affinity to the ryanodine receptor. In clinical studies, some variants have been associated with both CPVT4 and LQT15. This study uses simulations in a model for excitation-contraction coupling in the rat ventricular myocytes to understand how LQT14 variant might give the functional phenotype similar to CPVT4. Changing the CaM-dependent transition rate by a factor of 0.75 corresponding to the D96V variant and by a factor of 0.90 corresponding to the F142L or N98S variants, in a physiologically based stochastic model of the LCC prolonger, the action potential duration changed by a small amount in a cardiac myocyte but did not disrupt CICR at 1, 2, and 4 Hz. Under beta-adrenergic simulation abnormal excitation-contraction coupling was observed above 2 Hz pacing for the mutant CaM. The same conditions applied under beta-adrenergic stimulation led to the rapid onset of arrhythmia in the mutant CaM simulations. Simulations with the LQT14 mutations under the conditions of rapid pacing with beta-adrenergic stimulation drives the cardiac myocyte toward an arrhythmic state known as Ca2+ overload. These simulations provide a mechanistic link to a disease state for LQT14-associated mutations in CaM to yield a CPVT4 phenotype. The results show that small changes to the CaM-regulated inactivation of LCC promote arrhythmia and underscore the significance of CDI in proper heart function.
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Affiliation(s)
- Matthew D. McCoy
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Innovation Center for Biomedical Informatics, Department of Oncology, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, USA
| | - Aman Ullah
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
| | - W. Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
| | - M. Saleet Jafri
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
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Abstract
Flecainide, a cardiac class 1C blocker of the surface membrane sodium channel (NaV1.5), has also been reported to reduce cardiac ryanodine receptor (RyR2)-mediated sarcoplasmic reticulum (SR) Ca2+ release. It has been introduced as a clinical antiarrhythmic agent for catecholaminergic polymorphic ventricular tachycardia (CPVT), a condition most commonly associated with gain-of-function RyR2 mutations. Current debate concerns both cellular mechanisms of its antiarrhythmic action and molecular mechanisms of its RyR2 actions. At the cellular level, it targets NaV1.5, RyR2, Na+/Ca2+ exchange (NCX), and additional proteins involved in excitation-contraction (EC) coupling and potentially contribute to the CPVT phenotype. This Viewpoint primarily addresses the various direct molecular actions of flecainide on isolated RyR2 channels in artificial lipid bilayers. Such studies demonstrate different, multifarious, flecainide binding sites on RyR2, with voltage-dependent binding in the channel pore or voltage-independent binding at distant peripheral sites. In contrast to its single NaV1.5 pore binding site, flecainide may bind to at least four separate inhibitory sites on RyR2 and one activation site. None of these binding sites have been specifically located in the linear RyR2 sequence or high-resolution structure. Furthermore, it is not clear which of the inhibitory sites contribute to flecainide's reduction of spontaneous Ca2+ release in cellular studies. A confounding observation is that flecainide binding to voltage-dependent inhibition sites reduces cation fluxes in a direction opposite to physiological Ca2+ flow from SR lumen to cytosol. This may suggest that, rather than directly blocking Ca2+ efflux, flecainide can reduce Ca2+ efflux by blocking counter currents through the pore which otherwise limit SR membrane potential change during systolic Ca2+ efflux. In summary, the antiarrhythmic effects of flecainide in CPVT seem to involve multiple components of EC coupling and multiple actions on RyR2. Their clarification may identify novel specific drug targets and facilitate flecainide's clinical utilization in CPVT.
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Affiliation(s)
| | - Christopher L.-H. Huang
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - James A. Fraser
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Angela F. Dulhunty
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Acton, Australia
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14
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Bannister ML, MacLeod KT, George CH. Moving in the right direction: elucidating the mechanisms of interaction between flecainide and the cardiac ryanodine receptor. Br J Pharmacol 2022; 179:2558-2563. [PMID: 34698387 DOI: 10.1111/bph.15718] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/01/2021] [Accepted: 10/10/2021] [Indexed: 11/30/2022] Open
Abstract
Flecainide is used to treat catecholaminergic polymorphic ventricular tachycardia (CPVT), an arrhythmia caused by disrupted cellular Ca2+ handling following β-adrenergic stimulation. The clinical efficacy of flecainide in this context involves complex effects on multiple ion channels that may be influenced by the disease state. A compelling narrative has been constructed around flecainide's nonselective block of sarcoplasmic reticulum (SR) lumen-to-cytoplasm Ca2+ release through intracellular calcium release channels (RyR2). However, ion fluxes across the SR membrane during heart contraction are bidirectional, and here, we review experimental evidence that flecainide's principal action on RyR2 involves the partial block of ion flow in the cytoplasm-to-lumen direction (i.e., flecainide inhibits RyR2-mediated SR 'countercurrent'). Experimental approaches that could advance new knowledge on the mechanism of RyR2 block by flecainide are proposed. Some impediments to progress in this area, that must be overcome to enable the development of superior drugs to treat CPVT, are also considered.
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Affiliation(s)
- Mark L Bannister
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Kenneth T MacLeod
- National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, UK
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15
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Hadiatullah H, He Z, Yuchi Z. Structural Insight Into Ryanodine Receptor Channelopathies. Front Pharmacol 2022; 13:897494. [PMID: 35677449 PMCID: PMC9168041 DOI: 10.3389/fphar.2022.897494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/09/2022] [Indexed: 11/28/2022] Open
Abstract
The ryanodine receptors (RyRs) are large cation-selective ligand-gated channels that are expressed in the sarcoplasmic reticulum (SR) membrane. They mediate the controlled release of Ca2+ from SR and play an important role in many cellular processes. The mutations in RyRs are associated with several skeletal muscle and cardiac conditions, including malignant hyperthermia (MH), central core disease (CCD), catecholaminergic polymorphic ventricular tachycardia (CPVT), and arrhythmogenic right ventricular dysplasia (ARVD). Recent breakthroughs in structural biology including cryo-electron microscopy (EM) and X-ray crystallography allowed the determination of a number of near-atomic structures of RyRs, including wildtype and mutant structures as well as the structures in complex with different modulating molecules. This allows us to comprehend the physiological gating and regulatory mechanisms of RyRs and the underlying pathological mechanisms of the disease-causing mutations. In this review, based on the insights gained from the available high-resolution structures of RyRs, we address several questions: 1) what are the gating mechanisms of different RyR isoforms; 2) how RyRs are regulated by multiple channel modulators, including ions, small molecules, and regulatory proteins; 3) how do disease-causing mutations affect the structure and function of RyRs; 4) how can these structural information aid in the diagnosis of the related diseases and the development of pharmacological therapies.
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Affiliation(s)
- Hadiatullah Hadiatullah
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin’s Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Zhao He
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin’s Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin’s Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
- *Correspondence: Zhiguang Yuchi,
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Metabolically driven maturation of human-induced-pluripotent-stem-cell-derived cardiac microtissues on microfluidic chips. Nat Biomed Eng 2022; 6:372-388. [PMID: 35478228 DOI: 10.1038/s41551-022-00884-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 03/14/2022] [Indexed: 12/29/2022]
Abstract
The immature physiology of cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) limits their utility for drug screening and disease modelling. Here we show that suitable combinations of mechanical stimuli and metabolic cues can enhance the maturation of hiPSC-derived cardiomyocytes, and that the maturation-inducing cues have phenotype-dependent effects on the cells' action-potential morphology and calcium handling. By using microfluidic chips that enhanced the alignment and extracellular-matrix production of cardiac microtissues derived from genetically distinct sources of hiPSC-derived cardiomyocytes, we identified fatty-acid-enriched maturation media that improved the cells' mitochondrial structure and calcium handling, and observed divergent cell-source-dependent effects on action-potential duration (APD). Specifically, in the presence of maturation media, tissues with abnormally prolonged APDs exhibited shorter APDs, and tissues with aberrantly short APDs displayed prolonged APDs. Regardless of cell source, tissue maturation reduced variabilities in spontaneous beat rate and in APD, and led to converging cell phenotypes (with APDs within the 300-450 ms range characteristic of human left ventricular cardiomyocytes) that improved the modelling of the effects of pro-arrhythmic drugs on cardiac tissue.
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Emerging Antiarrhythmic Drugs for Atrial Fibrillation. Int J Mol Sci 2022; 23:ijms23084096. [PMID: 35456912 PMCID: PMC9029767 DOI: 10.3390/ijms23084096] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/28/2022] [Accepted: 04/01/2022] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF), the most common cardiac arrhythmia worldwide, is driven by complex mechanisms that differ between subgroups of patients. This complexity is apparent from the different forms in which AF presents itself (post-operative, paroxysmal and persistent), each with heterogeneous patterns and variable progression. Our current understanding of the mechanisms responsible for initiation, maintenance and progression of the different forms of AF has increased significantly in recent years. Nevertheless, antiarrhythmic drugs for the management of AF have not been developed based on the underlying arrhythmia mechanisms and none of the currently used drugs were specifically developed to target AF. With the increased knowledge on the mechanisms underlying different forms of AF, new opportunities for developing more effective and safer AF therapies are emerging. In this review, we provide an overview of potential novel antiarrhythmic approaches based on the underlying mechanisms of AF, focusing both on the development of novel antiarrhythmic agents and on the possibility of repurposing already marketed drugs. In addition, we discuss the opportunity of targeting some of the key players involved in the underlying AF mechanisms, such as ryanodine receptor type-2 (RyR2) channels and atrial-selective K+-currents (IK2P and ISK) for antiarrhythmic therapy. In addition, we highlight the opportunities for targeting components of inflammatory signaling (e.g., the NLRP3-inflammasome) and upstream mechanisms targeting fibroblast function to prevent structural remodeling and progression of AF. Finally, we critically appraise emerging antiarrhythmic drug principles and future directions for antiarrhythmic drug development, as well as their potential for improving AF management.
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Nolla‐Colomer C, Casabella‐Ramon S, Jimenez‐Sabado V, Vallmitjana A, Tarifa C, Herraiz‐Martínez A, Llach A, Tauron M, Montiel J, Cinca J, Chen SRW, Benitez R, Hove‐Madsen L. β2-adrenergic stimulation potentiates spontaneous calcium release by increasing signal mass and co-activation of ryanodine receptor clusters. Acta Physiol (Oxf) 2022; 234:e13736. [PMID: 34709723 DOI: 10.1111/apha.13736] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 01/18/2023]
Abstract
AIMS It is unknown how β-adrenergic stimulation affects calcium dynamics in individual RyR2 clusters and leads to the induction of spontaneous calcium waves. To address this, we analysed spontaneous calcium release events in green fluorescent protein (GFP)-tagged RyR2 clusters. METHODS Cardiomyocytes from mice with GFP-tagged RyR2 or human right atrial tissue were subjected to immunofluorescent labelling or confocal calcium imaging. RESULTS Spontaneous calcium release from single RyR2 clusters induced 91.4% ± 2.0% of all calcium sparks while 8.0% ± 1.6% were caused by release from two neighbouring clusters. Sparks with two RyR2 clusters had 40% bigger amplitude, were 26% wider, and lasted 35% longer at half maximum. Consequently, the spark mass was larger in two- than one-cluster sparks with a median and interquartile range for the cumulative distribution of 15.7 ± 20.1 vs 7.6 ± 5.7 a.u. (P < .01). β2-adrenergic stimulation increased RyR2 phosphorylation at s2809 and s2815, tripled the fraction of two- and three-cluster sparks, and significantly increased the spark mass. Interestingly, the amplitude and mass of the calcium released from a RyR2 cluster were proportional to the SR calcium load, but the firing rate was not. The spark mass was also higher in 33 patients with atrial fibrillation than in 36 without (22.9 ± 23.4 a.u. vs 10.7 ± 10.9; P = .015). CONCLUSIONS Most sparks are caused by activation of a single RyR2 cluster at baseline while β-adrenergic stimulation doubles the mass and the number of clusters per spark. This mimics the shift in the cumulative spark mass distribution observed in myocytes from patients with atrial fibrillation.
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Affiliation(s)
| | - Sergi Casabella‐Ramon
- Biomedical Research Institute Barcelona, IIBB‐CSIC Barcelona Spain
- IIB Sant Pau Barcelona Spain
| | | | | | - Carmen Tarifa
- Biomedical Research Institute Barcelona, IIBB‐CSIC Barcelona Spain
- IIB Sant Pau Barcelona Spain
| | - Adela Herraiz‐Martínez
- Biomedical Research Institute Barcelona, IIBB‐CSIC Barcelona Spain
- IIB Sant Pau Barcelona Spain
| | | | - Manel Tauron
- Department of Cardiac Surgery Hospital de la Santa Creu i Sant Pau Barcelona Spain
| | - Jose Montiel
- Department of Cardiac Surgery Hospital de la Santa Creu i Sant Pau Barcelona Spain
| | - Juan Cinca
- IIB Sant Pau Barcelona Spain
- Universitat Autònoma de Barcelona Barcelona Spain
| | - S. R. Wayne Chen
- Department of Physiology and Pharmacology University of Calgary Alberta Canada
| | - Raul Benitez
- Department Automatic Control Univ. Politècnica de Catalunya Barcelona Spain
| | - Leif Hove‐Madsen
- Biomedical Research Institute Barcelona, IIBB‐CSIC Barcelona Spain
- IIB Sant Pau Barcelona Spain
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19
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Jin Z, Hwang I, Lim B, Kwon OS, Park JW, Yu HT, Kim TH, Joung B, Lee MH, Pak HN. Anti-atrial Fibrillation Effects of Pulmonary Vein Isolation With or Without Ablation Gaps: A Computational Modeling Study. Front Physiol 2022; 13:846620. [PMID: 35370797 PMCID: PMC8968313 DOI: 10.3389/fphys.2022.846620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/24/2022] [Indexed: 01/22/2023] Open
Abstract
Background Although pulmonary vein isolation (PVI) gaps contribute to recurrence after atrial fibrillation (AF) catheter ablation, the mechanism is unclear. We used realistic computational human AF modeling to explore the AF wave-dynamic changes of PVI with gaps (PVI-gaps). Methods We included 40 patients (80% male, 61.0 ± 9.8 years old, 92.5% persistent AF) who underwent AF catheter ablation to develop our realistic computational AF model. We compared the effects of a complete PVI (CPVI) and PVI-gap (2-mm × 4) on the AF wave-dynamics by evaluating the dominant frequency (DF), spatial change of DF, maximal slope of the action potential duration restitution curve (Smax), and AF defragmentation rate (termination or change to atrial tachycardia), and tested the effects of additional virtual interventions and flecainide on ongoing AF with PVI-gaps. Results Compared with the baseline AF, CPVIs significantly reduced extra-PV DFs (p < 0.001), but PVI-gaps did not. COV-DFs were greater after CPVIs than PVI-gaps (p < 0.001). Neither CPVIs nor PVI-gaps changed the mean Smax. CPVIs resulted in higher AF defragmentation rates (80%) than PVI-gaps (12.5%, p < 0.001). In ongoing AF after PVI-gaps, the AF defragmentation rates after a wave-breaking gap ablation, extra-PV DF ablation, or flecainide were 60.0, 34.3, and 25.7%, respectively (p = 0.010). Conclusion CPVIs effectively reduced the DF, increased its spatial heterogeneity in extra-PV areas, and offered better anti-AF effects than extra-PV DF ablation or additional flecainide in PVI-gap conditions.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Hui-Nam Pak
- Yonsei University College of Medicine, Yonsei University Health System, Seoul, South Korea
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Li Y, Peng X, Lin R, Wang X, Liu X, Bai R, Ma C, Tang R, Ruan Y, Liu N. The Antiarrhythmic Mechanisms of Flecainide in Catecholaminergic Polymorphic Ventricular Tachycardia. Front Physiol 2022; 13:850117. [PMID: 35356081 PMCID: PMC8959698 DOI: 10.3389/fphys.2022.850117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/17/2022] [Indexed: 11/16/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe yet rare inherited arrhythmia disorder. The cornerstone of CPVT medical therapy is the use of β-blockers; 30% of patients with CPVT do not respond well to optimal β-blocker treatment. Studies have shown that flecainide effectively prevents life-threatening arrhythmias in CPVT. Flecainide is a class IC antiarrhythmic drug blocking cardiac sodium channels. RyR2 inhibition is proposed as the principal mechanism of antiarrhythmic action of flecainide in CPVT, while it is highly debated. In this article, we review the current progress of this issue.
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Affiliation(s)
- Yukun Li
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
| | - Xiaodong Peng
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
| | - Rong Lin
- North China Medical and Health Group XingTai Hospital, Xingtai, China
| | - Xuesi Wang
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
| | - Xinmeng Liu
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
| | - Rong Bai
- Banner – University Medical Center Phoenix, University of Arizona College of Medicine, Phoenix, AZ, United States
| | - Changsheng Ma
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
| | - Ribo Tang
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
- Ribo Tang,
| | - Yanfei Ruan
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
- Yanfei Ruan,
| | - Nian Liu
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Cardiovascular Diseases, Beijing, China
- *Correspondence: Nian Liu,
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21
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Drumm BT, Hannigan KI, Lee JY, Rembetski BE, Baker SA, Koh SD, Cobine CA, Sanders KM. Ca 2+ signalling in interstitial cells of Cajal contributes to generation and maintenance of tone in mouse and monkey lower esophageal sphincters. J Physiol 2022; 600:2613-2636. [PMID: 35229888 DOI: 10.1113/jp282570] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/15/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The lower esophageal sphincter (LES) generates contractile tone preventing reflux of gastric contents into the esophagus. LES smooth muscle cells (SMCs) display depolarized membrane potentials facilitating activation of L-type Ca2+ channels. Interstitial cells of Cajal (ICC) express Ca2+ -activated Cl- channels encoded by Ano1 in mouse and monkey LES. Ca2+ signaling in ICC activates ANO1 currents in ICC. ICC displayed spontaneous Ca2+ transients in mice from multiple firing sites in each cell and no entrainment of Ca2+ firing between sites or between cells. Inhibition of ANO1 channels with a specific antagonist caused hyperpolarization of mouse LES and inhibition of tone in monkey and mouse LES muscles. Our data suggest a novel mechanism for LES tone in which Ca2+ transient activation of ANO1 channels in ICC generates depolarizing inward currents that conduct to SMCs to activate L-type Ca2+ currents, Ca2+ entry and contractile tone. ABSTRACT The lower esophageal sphincter (LES) generates tone and prevents reflux of gastric contents. LES smooth muscle cells (SMCs) are relatively depolarized, facilitating activation of Cav 1.2 channels to sustain contractile tone. We hypothesised that intramuscular interstitial cells of Cajal (ICC-IM), through activation of Ca2+ -activated-Cl- channels (ANO1), set membrane potentials of SMCs favorable for activation of Cav 1.2 channels. In some gastrointestinal muscles, ANO1 channels in ICC-IM are activated by Ca2+ transients, but no studies have examined Ca2+ dynamics in ICC-IM within the LES. Immunohistochemistry and qPCR were used to determine expression of key proteins and genes in ICC-IM and SMCs. These studies revealed that Ano1 and its gene product, ANO1 are expressed in c-Kit+ cells (ICC-IM) in mouse and monkey LES clasp muscles. Ca2+ signaling was imaged in situ, using mice expressing GCaMP6f specifically in ICC (Kit-KI-GCaMP6f). ICC-IM exhibited spontaneous Ca2+ transients from multiple firing sites. Ca2+ transients were abolished by CPA or caffeine but were unaffected by tetracaine or nifedipine. Maintenance of Ca2+ transients depended on Ca2+ influx and store reloading, as Ca2+ transient frequency was reduced in Ca2+ free solution or by Orai antagonist. Spontaneous tone of LES muscles from mouse and monkey was reduced ∼80% either by Ani9, an ANO1 antagonist or by the Cav 1.2 channel antagonist nifedipine. Membrane hyperpolarisation occurred in the presence of Ani9. These data suggest that intracellular Ca2+ activates ANO1 channels in ICC-IM in the LES. Coupling of ICC-IM to SMCs drives depolarization, activation of Cav 1.2 channels, Ca2+ entry and contractile tone. Abstract figure legend Proposed mechanism for generation of contractile tone in the lower esophageal sphincter (LES). Interstitial cells of Cajal (ICC) in the LES generate spontaneous, stochastic Ca2+ transients via Ca2+ release from the endoplasmic reticulum (ER). The Ca2+ transients activate ANO1 Cl- channels causing Cl- efflux (inward current). ANO1 currents have a depolarizing effect on ICC (+++s inside membrane) and this conducts through gap junctions (GJ) to smooth muscle cells (SMCs). Input from thousands of ICC results in depolarized membrane potentials (-40 to -50 mV) which is within the window current range for L-type Ca2+ channels. Activation of these channels causes Ca2+ influx, activation of contractile elements (CE) and development of tonic contraction. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA.,Smooth Muscle Research Centre, Dundalk Institute of Technology, Ireland
| | - Karen I Hannigan
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Ji Yeon Lee
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Benjamin E Rembetski
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Salah A Baker
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Sang Don Koh
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Caroline A Cobine
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Chakraborty P, Massé S, Azam MA, Thollon C, Niri A, Lai PFH, Bouly M, Riazi S, Nanthakumar K. Effects of azumolene on arrhythmia substrate in a model of recurrent long-duration ventricular fibrillation. Biochem Biophys Res Commun 2022; 600:123-129. [PMID: 35219100 DOI: 10.1016/j.bbrc.2022.02.031] [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: 01/25/2022] [Accepted: 02/09/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Proarrhythmic risk of conventional anti-arrhythmic agents is linked to unintended modulation of membrane voltage dynamics. We have demonstrated that the anti-fibrillatory effect of azumolene is mediated via stabilization of the hyperphosphorylated ryanodine receptor (RyR2), leading to attenuation of diastolic calcium leak. However, the concomitant effects on membrane voltage dynamics have not been evaluated yet. METHODS After baseline optical mapping, Langendorff-perfused rabbit hearts treated with azumolene, or vehicle, were subjected to global ischemia-reperfusion (I/R) followed by two episodes of long-duration ventricular fibrillation (LDVF). Simultaneous dual epicardial calcium transient (CaT) and voltage dynamics were studied optically. RESULTS Pre-treatment with azumolene was associated with higher CaT amplitude alternans ratios (0.94 ± 0.02 vs. 0.78 ± 0.03 in control hearts, at 6 Hz; p = 0.005; and action potential amplitude alternans ratio (0.95 ± 0.02 vs. 0.78 ± 0.04 at 6.0 Hz; p = 0.02), and reduction of action potential duration (APD80) dispersion (9.0 ± 4.8 msec vs. 19.3 ± 6.6 msec at 6.0 Hz p = 0.02) and optical action potential upstroke rise time (26.3 ± 2.6 msec in control vs. 13.8 ± 0.6 msec at 6.0 Hz, p = 0.02) after LDVF. No change in action potential duration (APD) was noted with azumolene treatment. CONCLUSION In a model of ischemic recurrent LDVF, treatment with azumolene led to reduction of cardiac alternans, i.e., calcium and voltage alternans. Unlike conventional anti-arrhythmic agents, reduction of action potential upstroke rise time and preservation of action potential duration following azumolene treatment may reduce the proarrhythmia risk.
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Affiliation(s)
- Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Stéphane Massé
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Mohammed Ali Azam
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | | | - Ahmed Niri
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Patrick F H Lai
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Muriel Bouly
- Institut de Recherches Internationales Servier (IRIS), Suresnes, France
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Department of Anesthesia and Pain Management, University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
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23
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Morciano G, Rimessi A, Patergnani S, Vitto VAM, Danese A, Kahsay A, Palumbo L, Bonora M, Wieckowski MR, Giorgi C, Pinton P. Calcium dysregulation in heart diseases: Targeting calcium channels to achieve a correct calcium homeostasis. Pharmacol Res 2022; 177:106119. [PMID: 35131483 DOI: 10.1016/j.phrs.2022.106119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 12/16/2022]
Abstract
Intracellular calcium signaling is a universal language source shared by the most part of biological entities inside cells that, all together, give rise to physiological and functional anatomical units, the organ. Although preferentially recognized as signaling between cell life and death processes, in the heart it assumes additional relevance considered the importance of calcium cycling coupled to ATP consumption in excitation-contraction coupling. The concerted action of a plethora of exchangers, channels and pumps inward and outward calcium fluxes where needed, to convert energy and electric impulses in muscle contraction. All this without realizing it, thousands of times, every day. An improper function of those proteins (i.e., variation in expression, mutations onset, dysregulated channeling, differential protein-protein interactions) being part of this signaling network triggers a short circuit with severe acute and chronic pathological consequences reported as arrhythmias, cardiac remodeling, heart failure, reperfusion injury and cardiomyopathies. By acting with chemical, peptide-based and pharmacological modulators of these players, a correction of calcium homeostasis can be achieved accompanied by an amelioration of clinical symptoms. This review will focus on all those defects in calcium homeostasis which occur in the most common cardiac diseases, including myocardial infarction, arrhythmia, hypertrophy, heart failure and cardiomyopathies. This part will be introduced by the state of the art on the proteins involved in calcium homeostasis in cardiomyocytes and followed by the therapeutic treatments that to date, are able to target them and to revert the pathological phenotype.
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Affiliation(s)
- Giampaolo Morciano
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
| | - Alessandro Rimessi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Simone Patergnani
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Veronica A M Vitto
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Alberto Danese
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Asrat Kahsay
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Laura Palumbo
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Massimo Bonora
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism. Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
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24
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Kwon OS, Hwang I, Pak HN. Computational modeling of atrial fibrillation. INTERNATIONAL JOURNAL OF ARRHYTHMIA 2021. [DOI: 10.1186/s42444-021-00051-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractWith the aging society, the prevalence of atrial fibrillation (AF) continues to increase. Nevertheless, there are still limitations in antiarrhythmic drugs (AAD) or catheter interventions for AF. If it is possible to predict the outcome of AF management according to various AADs or ablation lesion sets through computational modeling, it will be of great clinical help. AF computational modeling has been utilized for in-silico arrhythmia research and enabled high-density entire chamber mapping, reproducible condition control, virtual intervention, not possible clinically or experimentally, in-depth mechanistic research. With the recent development of computer science and technology, more sophisticated and faster computational modeling has become available for clinical application. In particular, it can be applied to determine the extra-PV target of persistent AF catheter ablation or to select the AAD with the best effect. AF computational modeling combined with artificial intelligence is expected to contribute to precision medicine for more diverse uses in the future. Therefore, in this review, we will deal with the history, development, and various applications of computation modeling.
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25
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Ca2+-dependent modulation of voltage-gated myocyte sodium channels. Biochem Soc Trans 2021; 49:1941-1961. [PMID: 34643236 PMCID: PMC8589445 DOI: 10.1042/bst20200604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/01/2021] [Accepted: 08/31/2021] [Indexed: 12/19/2022]
Abstract
Voltage-dependent Na+ channel activation underlies action potential generation fundamental to cellular excitability. In skeletal and cardiac muscle this triggers contraction via ryanodine-receptor (RyR)-mediated sarcoplasmic reticular (SR) Ca2+ release. We here review potential feedback actions of intracellular [Ca2+] ([Ca2+]i) on Na+ channel activity, surveying their structural, genetic and cellular and functional implications, translating these to their possible clinical importance. In addition to phosphorylation sites, both Nav1.4 and Nav1.5 possess potentially regulatory binding sites for Ca2+ and/or the Ca2+-sensor calmodulin in their inactivating III–IV linker and C-terminal domains (CTD), where mutations are associated with a range of skeletal and cardiac muscle diseases. We summarize in vitro cell-attached patch clamp studies reporting correspondingly diverse, direct and indirect, Ca2+ effects upon maximal Nav1.4 and Nav1.5 currents (Imax) and their half-maximal voltages (V1/2) characterizing channel gating, in cellular expression systems and isolated myocytes. Interventions increasing cytoplasmic [Ca2+]i down-regulated Imax leaving V1/2 constant in native loose patch clamped, wild-type murine skeletal and cardiac myocytes. They correspondingly reduced action potential upstroke rates and conduction velocities, causing pro-arrhythmic effects in intact perfused hearts. Genetically modified murine RyR2-P2328S hearts modelling catecholaminergic polymorphic ventricular tachycardia (CPVT), recapitulated clinical ventricular and atrial pro-arrhythmic phenotypes following catecholaminergic challenge. These accompanied reductions in action potential conduction velocities. The latter were reversed by flecainide at RyR-blocking concentrations specifically in RyR2-P2328S as opposed to wild-type hearts, suggesting a basis for its recent therapeutic application in CPVT. We finally explore the relevance of these mechanisms in further genetic paradigms for commoner metabolic and structural cardiac disease.
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26
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Rolland T, Badenco N, Maupain C, Duthoit G, Waintraub X, Laredo M, Himbert C, Frank R, Hidden-Lucet F, Gandjbakhch E. Safety and efficacy of flecainide associated with beta-blockers in arrhythmogenic right ventricular cardiomyopathy. Europace 2021; 24:278-284. [PMID: 34459901 DOI: 10.1093/europace/euab182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/05/2021] [Indexed: 11/14/2022] Open
Abstract
AIMS Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy associated with a high risk of ventricular arrhythmia (VA). Current guidelines recommend beta-blockers as first-line medical therapy and if ineffective, sotalol or amiodarone. We describe our experience, as a tertiary centre for ARVC, with the effectiveness and tolerance of flecainide in addition to beta-blockers to prevent VA in ARVC. METHODS AND RESULTS We retrospectively included 100 consecutive ARVC patients who received flecainide with beta-blockers between May 1999 and November 2017. Treatment persistence and related side effects were assessed, as was VA-free survival on treatment, 24-h Holter monitoring and programmed ventricular stimulation (PVS) off- and on-treatment. Tolerance was good, with 10% flecainide discontinuations (lack of efficacy in six, atrial fibrillation in one, and side effects in three). No Brugada-induced electrocardiography pattern on flecainide or haemodynamic impairment was reported. Premature ventricular contraction burden at 24-h Holter monitoring was significantly decreased under treatment [median 415 (interquartile range, IQR 97-730) vs. 2370 (1572-3400) at baseline, P < 0.0001, n = 46]. Among the 33 patients with PVS under treatment, PVS was positive in 40% on-treatment vs. 94% off-treatment (P < 0.001). During a median follow-up of 47 months (IQR 23-73), 22 patients presented sustained VA on treatment, corresponding to an event rate of 5% [95% confidence interval (CI) (0.6-9)] at 1 year and 25% [95% CI (14-35)] at 5 years under treatment. No patient died. CONCLUSION This study suggests that flecainide and beta-blockers association is complementary to implantable cardioverter-defibrillator and catheter ablation and is safe for treating persistent symptomatic VA in patients with ARVC.
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Affiliation(s)
- Thomas Rolland
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Nicolas Badenco
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Carole Maupain
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Department of Genetics, Paris, France
| | - Guillaume Duthoit
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Xavier Waintraub
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Mikael Laredo
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Caroline Himbert
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Robert Frank
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Francoise Hidden-Lucet
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
| | - Estelle Gandjbakhch
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Institute of Cardiology, Paris, France.,Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.,Action Coeur Study Groupe, Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), Paris, France.,APHP, Pitié-Salpêtriére University Hospital, Department of Genetics, Paris, France
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27
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Flecainide in Ventricular Arrhythmias: From Old Myths to New Perspectives. J Clin Med 2021; 10:jcm10163696. [PMID: 34441994 PMCID: PMC8397118 DOI: 10.3390/jcm10163696] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/10/2021] [Accepted: 08/18/2021] [Indexed: 11/21/2022] Open
Abstract
Flecainide is an IC antiarrhythmic drug (AAD) that received in 1984 Food and Drug Administration approval for the treatment of sustained ventricular tachycardia (VT) and subsequently for rhythm control of atrial fibrillation (AF). Currently, flecainide is mainly employed for sinus rhythm maintenance in AF and the treatment of idiopathic ventricular arrhythmias (IVA) in absence of ischaemic and structural heart disease on the basis of CAST data. Recent studies enrolling patients with different structural heart diseases demonstrated good effectiveness and safety profile of flecainide. The purpose of this review is to assess current evidence for appropriate and safe use of flecainide, 30 years after CAST data, in the light of new diagnostic and therapeutic tools in the field of ischaemic and non-ischaemic heart disease.
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28
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Salvage SC, Gallant EM, Fraser JA, Huang CLH, Dulhunty AF. Flecainide Paradoxically Activates Cardiac Ryanodine Receptor Channels under Low Activity Conditions: A Potential Pro-Arrhythmic Action. Cells 2021; 10:cells10082101. [PMID: 34440870 PMCID: PMC8394964 DOI: 10.3390/cells10082101] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/02/2022] Open
Abstract
Cardiac ryanodine receptor (RyR2) mutations are implicated in the potentially fatal catecholaminergic polymorphic ventricular tachycardia (CPVT) and in atrial fibrillation. CPVT has been successfully treated with flecainide monotherapy, with occasional notable exceptions. Reported actions of flecainide on cardiac sodium currents from mice carrying the pro-arrhythmic homozygotic RyR2-P2328S mutation prompted our explorations of the effects of flecainide on their RyR2 channels. Lipid bilayer electrophysiology techniques demonstrated a novel, paradoxical increase in RyR2 activity. Preceding flecainide exposure, channels were mildly activated by 1 mM luminal Ca2+ and 1 µM cytoplasmic Ca2+, with open probabilities (Po) of 0.03 ± 0.01 (wild type, WT) or 0.096 ± 0.024 (P2328S). Open probability (Po) increased within 0.5 to 3 min of exposure to 0.5 to 5.0 µM cytoplasmic flecainide, then declined with higher concentrations of flecainide. There were no such increases in a subset of high Po channels with Po ≥ 0.08, although Po then declined with ≥5 µM (WT) or ≥50 µM flecainide (P2328S). On average, channels with Po < 0.08 were significantly activated by 0.5 to 10 µM of flecainide (WT) or 0.5 to 50 µM of flecainide (P2328S). These results suggest that flecainide can bind to separate activation and inhibition sites on RyR2, with activation dominating in lower activity channels and inhibition dominating in more active channels.
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Affiliation(s)
- Samantha C. Salvage
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK; (S.C.S.); (J.A.F.); (C.L.-H.H.)
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Esther M. Gallant
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Acton 2601, Australia;
| | - James A. Fraser
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK; (S.C.S.); (J.A.F.); (C.L.-H.H.)
| | - Christopher L.-H. Huang
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK; (S.C.S.); (J.A.F.); (C.L.-H.H.)
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Angela F. Dulhunty
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Acton 2601, Australia;
- Correspondence:
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29
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Yang PC, Giles WR, Belardinelli L, Clancy CE. Mechanisms of flecainide induced negative inotropy: An in silico study. J Mol Cell Cardiol 2021; 158:26-37. [PMID: 34004185 PMCID: PMC8772296 DOI: 10.1016/j.yjmcc.2021.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/27/2022]
Abstract
It is imperative to develop better approaches to predict how antiarrhythmic drugs with multiple interactions and targets may alter the overall electrical and/or mechanical function of the heart. Safety Pharmacology studies have provided new insights into the multi-target effects of many different classes of drugs and have been aided by the addition of robust new in vitro and in silico technology. The primary focus of Safety Pharmacology studies has been to determine the risk profile of drugs and drug candidates by assessing their effects on repolarization of the cardiac action potential. However, for decades experimental and clinical studies have described substantial and potentially detrimental effects of Na+ channel blockers in addition to their well-known conduction slowing effects. One such side effect, associated with administration of some Na+ channel blocking drugs is negative inotropy. This reduces the pumping function of the heart, thereby resulting in hypotension. Flecainide is a well-known example of a Na+ channel blocking drug, that exhibits strong rate-dependent block of INa and may cause negative cardiac inotropy. While the phenomenon of Na+ channel suppression and resulting negative inotropy is well described, the mechanism(s) underlying this effect are not. Here, we set out to use a modeling and simulation approach to reveal plausible mechanisms that could explain the negative inotropic effect of flecainide. We utilized the Grandi-Bers model [1] of the cardiac ventricular myocyte because of its robust descriptions of ion homeostasis in order to characterize and resolve the relative effects of QRS widening, flecainide off-target effects and changes in intracellular Ca2+ and Na+ homeostasis. The results of our investigations and predictions reconcile multiple data sets and illustrate how multiple mechanisms may play a contributing role in the flecainide induced negative cardiac inotropic effect.
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Affiliation(s)
- Pei-Chi Yang
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, United States of America
| | - Wayne R Giles
- Department of Physiology & Pharmacology, University of Calgary, Canada
| | | | - Colleen E Clancy
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, United States of America.
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30
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Hwang I, Jin Z, Park JW, Kwon OS, Lim B, Hong M, Kim M, Yu HT, Kim TH, Uhm JS, Joung B, Lee MH, Pak HN. Computational Modeling for Antiarrhythmic Drugs for Atrial Fibrillation According to Genotype. Front Physiol 2021; 12:650449. [PMID: 34054570 PMCID: PMC8155488 DOI: 10.3389/fphys.2021.650449] [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: 01/08/2021] [Accepted: 03/22/2021] [Indexed: 01/11/2023] Open
Abstract
Background: The efficacy of antiarrhythmic drugs (AAD) can vary in patients with atrial fibrillation (AF), and the PITX2 gene affects the responsiveness of AADs. We explored the virtual AAD (V-AAD) responses between wild-type and PITX2 +/--deficient AF conditions by realistic in silico AF modeling. Methods: We tested the V-AADs in AF modeling integrated with patients' 3D-computed tomography and 3D-electroanatomical mapping, acquired in 25 patients (68% male, 59.8 ± 9.8 years old, 32.0% paroxysmal type). The ion currents for the PITX2 +/- deficiency and each AAD (amiodarone, sotalol, dronedarone, flecainide, and propafenone) were defined based on previous publications. Results: We compared the wild-type and PITX2 +/- deficiency in terms of the action potential duration (APD90), conduction velocity (CV), maximal slope of restitution (Smax), and wave-dynamic parameters, such as the dominant frequency (DF), phase singularities (PS), and AF termination rates according to the V-AADs. The PITX2 +/--deficient model exhibited a shorter APD90 (p < 0.001), a lower Smax (p < 0.001), mean DF (p = 0.012), PS number (p < 0.001), and a longer AF cycle length (AFCL, p = 0.011). Five V-AADs changed the electrophysiology in a dose-dependent manner. AAD-induced AFCL lengthening (p < 0.001) and reductions in the CV (p = 0.033), peak DF (p < 0.001), and PS number (p < 0.001) were more significant in PITX2 +/--deficient than wild-type AF. PITX2 +/--deficient AF was easier to terminate with class IC AADs than the wild-type AF (p = 0.018). Conclusions: The computational modeling-guided AAD test was feasible for evaluating the efficacy of multiple AADs in patients with AF. AF wave-dynamic and electrophysiological characteristics are different among the PITX2-deficient and the wild-type genotype models.
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31
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Moreau A, Reisqs J, Delanoe‐Ayari H, Pierre M, Janin A, Deliniere A, Bessière F, Meli AC, Charrabi A, Lafont E, Valla C, Bauer D, Morel E, Gache V, Millat G, Nissan X, Faucherre A, Jopling C, Richard S, Mejat A, Chevalier P. Deciphering DSC2 arrhythmogenic cardiomyopathy electrical instability: From ion channels to ECG and tailored drug therapy. Clin Transl Med 2021; 11:e319. [PMID: 33784018 PMCID: PMC7908047 DOI: 10.1002/ctm2.319] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Severe ventricular rhythm disturbances are the hallmark of arrhythmogenic cardiomyopathy (ACM), and are often explained by structural conduction abnormalities. However, comprehensive investigations of ACM cell electrical instability are lacking. This study aimed to elucidate early electrical myogenic signature of ACM. METHODS We investigated a 41-year-old ACM patient with a missense mutation (c.394C>T) in the DSC2 gene, which encodes desmocollin 2. Pathogenicity of this variant was confirmed using a zebrafish DSC2 model system. Control and DSC2 patient-derived pluripotent stem cells were reprogrammed and differentiated into cardiomyocytes (hiPSC-CM) to examine the specific electromechanical phenotype and its modulation by antiarrhythmic drugs (AADs). Samples of the patient's heart and hiPSC-CM were examined to identify molecular and cellular alterations. RESULTS A shortened action potential duration was associated with reduced Ca2+ current density and increased K+ current density. This finding led to the elucidation of previously unknown abnormal repolarization dynamics in ACM patients. Moreover, the Ca2+ mobilised during transients was decreased, and the Ca2+ sparks frequency was increased. AAD testing revealed the following: (1) flecainide normalised Ca2+ transients and significantly decreased Ca2+ spark occurrence and (2) sotalol significantly lengthened the action potential and normalised the cells' contractile properties. CONCLUSIONS Thorough analysis of hiPSC-CM derived from the DSC2 patient revealed abnormal repolarization dynamics, prompting the discovery of a short QT interval in some ACM patients. Overall, these results confirm a myogenic origin of ACM electrical instability and provide a rationale for prescribing class 1 and 3 AADs in ACM patients with increased ventricular repolarization reserve.
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Affiliation(s)
- Adrien Moreau
- PhyMedExpINSERM U1046CNRS UMR9214Université de MontpellierMontpellierFrance
| | - Jean‐Baptiste Reisqs
- PhyMedExpINSERM U1046CNRS UMR9214Université de MontpellierMontpellierFrance
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | | | - Marion Pierre
- PhyMedExpINSERM U1046CNRS UMR9214Université de MontpellierMontpellierFrance
| | - Alexandre Janin
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
- Service de RythmologieHospices Civils de LyonLyonFrance
- Laboratoire de Cardiogénétique moléculaireCentre de biologie et pathologie EstBronFrance
| | | | | | - Albano C. Meli
- PhyMedExpINSERM U1046CNRS UMR9214Université de MontpellierMontpellierFrance
| | - Azzouz Charrabi
- PhyMedExpINSERM U1046CNRS UMR9214Université de MontpellierMontpellierFrance
| | - Estele Lafont
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | - Camille Valla
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | - Delphine Bauer
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | - Elodie Morel
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | - Vincent Gache
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | - Gilles Millat
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
- Service de RythmologieHospices Civils de LyonLyonFrance
- Laboratoire de Cardiogénétique moléculaireCentre de biologie et pathologie EstBronFrance
| | | | | | - Chris Jopling
- IGF, CNRS, INSERMUniversité de MontpellierMontpellierFrance
| | - Sylvain Richard
- PhyMedExpINSERM U1046CNRS UMR9214Université de MontpellierMontpellierFrance
| | - Alexandre Mejat
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
| | - Philippe Chevalier
- Neuromyogene InstitutClaude Bernard University, Lyon 1VilleurbanneFrance
- Service de RythmologieHospices Civils de LyonLyonFrance
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Kryshtal DO, Blackwell DJ, Egly CL, Smith AN, Batiste SM, Johnston JN, Laver DR, Knollmann BC. RYR2 Channel Inhibition Is the Principal Mechanism of Flecainide Action in CPVT. Circ Res 2021; 128:321-331. [PMID: 33297863 PMCID: PMC7864884 DOI: 10.1161/circresaha.120.316819] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
RATIONALE The class Ic antiarrhythmic drug flecainide prevents ventricular tachyarrhythmia in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), a disease caused by hyperactive RyR2 (cardiac ryanodine receptor) mediated calcium (Ca) release. Although flecainide inhibits single RyR2 channels in vitro, reports have claimed that RyR2 inhibition by flecainide is not relevant for its mechanism of antiarrhythmic action and concluded that sodium channel block alone is responsible for flecainide's efficacy in CPVT. OBJECTIVE To determine whether RyR2 block independently contributes to flecainide's efficacy for suppressing spontaneous sarcoplasmic reticulum Ca release and for preventing ventricular tachycardia in vivo. METHODS AND RESULTS We synthesized N-methylated flecainide analogues (QX-flecainide and N-methyl flecainide) and showed that N-methylation reduces flecainide's inhibitory potency on RyR2 channels incorporated into artificial lipid bilayers. N-methylation did not alter flecainide's inhibitory activity on human cardiac sodium channels expressed in HEK293T cells. Antiarrhythmic efficacy was tested utilizing a Casq2 (cardiac calsequestrin) knockout (Casq2-/-) CPVT mouse model. In membrane-permeabilized Casq2-/- cardiomyocytes-lacking intact sarcolemma and devoid of sodium channel contribution-flecainide, but not its analogues, suppressed RyR2-mediated Ca release at clinically relevant concentrations. In voltage-clamped, intact Casq2-/- cardiomyocytes pretreated with tetrodotoxin to inhibit sodium channels and isolate the effect of flecainide on RyR2, flecainide significantly reduced the frequency of spontaneous sarcoplasmic reticulum Ca release, while QX-flecainide and N-methyl flecainide did not. In vivo, flecainide effectively suppressed catecholamine-induced ventricular tachyarrhythmias in Casq2-/- mice, whereas N-methyl flecainide had no significant effect on arrhythmia burden, despite comparable sodium channel block. CONCLUSIONS Flecainide remains an effective inhibitor of RyR2-mediated arrhythmogenic Ca release even when cardiac sodium channels are blocked. In mice with CPVT, sodium channel block alone did not prevent ventricular tachycardia. Hence, RyR2 channel inhibition likely constitutes the principal mechanism of antiarrhythmic action of flecainide in CPVT.
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Affiliation(s)
- Dmytro O Kryshtal
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN (D.O.K., D.J.B., C.L.E., B.C.K.)
| | - Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN (D.O.K., D.J.B., C.L.E., B.C.K.)
| | - Christian L Egly
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN (D.O.K., D.J.B., C.L.E., B.C.K.)
| | - Abigail N Smith
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN (A.N.S., S.M.B., J.N.J.)
| | - Suzanne M Batiste
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN (A.N.S., S.M.B., J.N.J.)
| | - Jeffrey N Johnston
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN (A.N.S., S.M.B., J.N.J.)
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia (D.R.L.)
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN (D.O.K., D.J.B., C.L.E., B.C.K.)
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Zhang XH, Wei H, Xia Y, Morad M. Calcium signaling consequences of RyR2 mutations associated with CPVT1 introduced via CRISPR/Cas9 gene editing in human-induced pluripotent stem cell-derived cardiomyocytes: Comparison of RyR2-R420Q, F2483I, and Q4201R. Heart Rhythm 2021; 18:250-260. [PMID: 32931925 PMCID: PMC7893824 DOI: 10.1016/j.hrthm.2020.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) created from patients with catecholaminergic polymorphic ventricular tachycardia 1 (CPVT1) have been used to study CPVT1 arrhythmia. OBJECTIVE The purpose of this study was to evaluate the Ca2+ signaling aberrancies and pharmacological sensitivities of 3 CRISPR/Cas9-introduced CPVT1 mutations located in different molecular domains of ryanodine receptor 2 (RyR2). METHODS CRISPR/Cas9-engineered hiPSC-CMs carrying RyR2 mutations-R420Q, Q4201R, and F2483I-were voltage clamped, and their electrophysiology, pharmacology, and Ca2+ signaling phenotypes measured using total internal reflection fluorescence microscopy. RESULTS R420Q and Q4201R mutant hiPSC-CMs exhibit irregular, long-lasting, spatially wandering Ca2+ sparks and aberrant Ca2+ releases similar to F2483I unlike the wild-type myocytes. Large sarcoplasmic reticulum (SR) Ca2+ leaks and smaller SR Ca2+ contents were detected in cells expressing Q4201R and F2483I, but not R420Q. Fractional Ca2+ release and calcium-induced calcium release gain were higher in Q4201R than in R420Q and F2483I hiPSC-CMs. JTV519 was equally effective in suppressing Ca2+ sparks, waves, and SR Ca2+ leaks in hiPSC-CMs derived from all 3 mutant lines. Flecainide and dantrolene similarly suppressed SR Ca2+ leaks, but were less effective in decreasing spark frequency and durations. CONCLUSION CRISPR/Cas9 gene editing of hiPSCs provides a novel approach in studying CPVT1-associated RyR2 mutations and suggests that Ca2+-signaling aberrancies and drug sensitivities may vary depending on the mutation site.
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Affiliation(s)
- Xiao-Hua Zhang
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina
| | - Hua Wei
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina
| | - Yanli Xia
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina
| | - Martin Morad
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina.
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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Lemme M, Braren I, Prondzynski M, Aksehirlioglu B, Ulmer BM, Schulze ML, Ismaili D, Meyer C, Hansen A, Christ T, Lemoine MD, Eschenhagen T. Chronic intermittent tachypacing by an optogenetic approach induces arrhythmia vulnerability in human engineered heart tissue. Cardiovasc Res 2020; 116:1487-1499. [PMID: 31598634 PMCID: PMC7314638 DOI: 10.1093/cvr/cvz245] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 07/31/2019] [Accepted: 10/04/2019] [Indexed: 01/01/2023] Open
Abstract
AIMS Chronic tachypacing is commonly used in animals to induce cardiac dysfunction and to study mechanisms of heart failure and arrhythmogenesis. Human induced pluripotent stem cells (hiPSC) may replace animal models to overcome species differences and ethical problems. Here, 3D engineered heart tissue (EHT) was used to investigate the effect of chronic tachypacing on hiPSC-cardiomyocytes (hiPSC-CMs). METHODS AND RESULTS To avoid cell toxicity by electrical pacing, we developed an optogenetic approach. EHTs were transduced with lentivirus expressing channelrhodopsin-2 (H134R) and stimulated by 15 s bursts of blue light pulses (0.3 mW/mm2, 30 ms, 3 Hz) separated by 15 s without pacing for 3 weeks. Chronic optical tachypacing did not affect contractile peak force, but induced faster contraction kinetics, shorter action potentials, and shorter effective refractory periods. This electrical remodelling increased vulnerability to tachycardia episodes upon electrical burst pacing. Lower calsequestrin 2 protein levels, faster diastolic depolarization (DD) and efficacy of JTV-519 (46% at 1 µmol/L) to terminate tachycardia indicate alterations of Ca2+ handling being part of the underlying mechanism. However, other antiarrhythmic compounds like flecainide (69% at 1 µmol/L) and E-4031 (100% at 1 µmol/L) were also effective, but not ivabradine (1 µmol/L) or SEA0400 (10 µmol/L). CONCLUSION We demonstrated a high vulnerability to tachycardia of optically tachypaced hiPSC-CMs in EHT and the effective termination by ryanodine receptor stabilization, sodium or hERG potassium channel inhibition. This new model might serve as a preclinical tool to test antiarrhythmic drugs increasing the insight in treating ventricular tachycardia.
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Affiliation(s)
- Marta Lemme
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Ingke Braren
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Maksymilian Prondzynski
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Bülent Aksehirlioglu
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Bärbel M Ulmer
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Mirja L Schulze
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Djemail Ismaili
- Department of Cardiology-Electrophysiology, University Heart Center, 20246 Hamburg, Germany
| | - Christian Meyer
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
- Department of Cardiology-Electrophysiology, University Heart Center, 20246 Hamburg, Germany
| | - Arne Hansen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Marc D Lemoine
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
- Department of Cardiology-Electrophysiology, University Heart Center, 20246 Hamburg, Germany
| | - Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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37
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Ashna A, van Helden DF, Dos Remedios C, Molenaar P, Laver DR. Phenytoin Reduces Activity of Cardiac Ryanodine Receptor 2; A Potential Mechanism for Its Cardioprotective Action. Mol Pharmacol 2020; 97:250-258. [PMID: 32015008 DOI: 10.1124/mol.119.117721] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Phenytoin is a hydantoin derivative that is used clinically for the treatment of epilepsy and has been reported to have antiarrhythmic actions on the heart. In a failing heart, the elevated diastolic Ca2+ leak from the sarcoplasmic reticulum can be normalized by the cardiac ryanodine receptor 2 (RyR2) inhibitor, dantrolene, without inhibiting Ca2+ release during systole or affecting Ca2+ release in normal healthy hearts. Unfortunately, dantrolene is hepatotoxic and unsuitable for chronic long-term administration. Because phenytoin and dantrolene belong to the hydantoin class of compounds, we test the hypothesis that dantrolene and phenytoin have similar inhibitory effects on RyR2 using a single-channel recording of RyR2 activity in artificial lipid bilayers. Phenytoin produced a reversible inhibition of RyR2 channels from sheep and human failing hearts. It followed a hyperbolic dose response with maximal inhibition of ∼50%, Hill coefficient ∼1, and IC50 ranging from 10 to 20 µM. It caused inhibition at diastolic cytoplasmic [Ca2+] but not at Ca2+ levels in the dyadic cleft during systole. Notably, phenytoin inhibits RyR2 from failing human heart but not from healthy heart, indicating that phenytoin may selectively target defective RyR2 channels in humans. We conclude that phenytoin could effectively inhibit RyR2-mediated release of Ca2+ in a manner paralleling that of dantrolene. Moreover, the IC50 of phenytoin in RyR2 is at least threefold lower than for other ion channels and clinically used serum levels, pointing to phenytoin as a more human-safe alternative to dantrolene for therapies against heart failure and cardiac arrythmias. SIGNIFICANCE STATEMENT: We show that phenytoin, a Na channel blocker used clinically for treatment of epilepsy, is a diastolic inhibitor of cardiac calcium release channels [cardiac ryanodine receptor 2 (RyR2)] at doses threefold lower than its current therapeutic levels. Phenytoin inhibits RyR2 from failing human heart and not from healthy heart, indicating that phenytoin may selectively target defective RyR2 channels in humans and pointing to phenytoin as a more human-safe alternative to dantrolene for therapies against heart failure and cardiac arrhythmias.
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Affiliation(s)
- A Ashna
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - D F van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - C Dos Remedios
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - P Molenaar
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - D R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
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Sparrow AJ, Sievert K, Patel S, Chang YF, Broyles CN, Brook FA, Watkins H, Geeves MA, Redwood CS, Robinson P, Daniels MJ. Measurement of Myofilament-Localized Calcium Dynamics in Adult Cardiomyocytes and the Effect of Hypertrophic Cardiomyopathy Mutations. Circ Res 2020; 124:1228-1239. [PMID: 30732532 PMCID: PMC6485313 DOI: 10.1161/circresaha.118.314600] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Supplemental Digital Content is available in the text. Rationale: Subcellular Ca2+ indicators have yet to be developed for the myofilament where disease mutation or small molecules may alter contractility through myofilament Ca2+ sensitivity. Here, we develop and characterize genetically encoded Ca2+ indicators restricted to the myofilament to directly visualize Ca2+ changes in the sarcomere. Objective: To produce and validate myofilament-restricted Ca2+ imaging probes in an adenoviral transduction adult cardiomyocyte model using drugs that alter myofilament function (MYK-461, omecamtiv mecarbil, and levosimendan) or following cotransduction of 2 established hypertrophic cardiomyopathy disease-causing mutants (cTnT [Troponin T] R92Q and cTnI [Troponin I] R145G) that alter myofilament Ca2+ handling. Methods and Results: When expressed in adult ventricular cardiomyocytes RGECO-TnT (Troponin T)/TnI (Troponin I) sensors localize correctly to the sarcomere without contractile impairment. Both sensors report cyclical changes in fluorescence in paced cardiomyocytes with reduced Ca2+ on and increased Ca2+ off rates compared with unconjugated RGECO. RGECO-TnT/TnI revealed changes to localized Ca2+ handling conferred by MYK-461 and levosimendan, including an increase in Ca2+ binding rates with both levosimendan and MYK-461 not detected by an unrestricted protein sensor. Coadenoviral transduction of RGECO-TnT/TnI with hypertrophic cardiomyopathy causing thin filament mutants showed that the mutations increase myofilament [Ca2+] in systole, lengthen time to peak systolic [Ca2+], and delay [Ca2+] release. This contrasts with the effect of the same mutations on cytoplasmic Ca2+, when measured using unrestricted RGECO where changes to peak systolic Ca2+ are inconsistent between the 2 mutations. These data contrast with previous findings using chemical dyes that show no alteration of [Ca2+] transient amplitude or time to peak Ca2+. Conclusions: RGECO-TnT/TnI are functionally equivalent. They visualize Ca2+ within the myofilament and reveal unrecognized aspects of small molecule and disease-associated mutations in living cells.
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Affiliation(s)
- Alexander J Sparrow
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Kolja Sievert
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Suketu Patel
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Yu-Fen Chang
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Connor N Broyles
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Frances A Brook
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Hugh Watkins
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,Department of Cardiology, Oxford University NHS Hospitals Trust, United Kingdom (H.W., M.J.D.)
| | - Michael A Geeves
- Department of Biosciences, University of Kent, Canterbury, United Kingdom (M.A.G.)
| | - Charles S Redwood
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Paul Robinson
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom
| | - Matthew J Daniels
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine (A.J.S., K.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Research Excellence (A.J.S., S.P., Y.-F.C., C.N.B., F.A.B., H.W., C.S.R., P.R., M.J.D.), University of Oxford, United Kingdom.,BHF Centre of Regenerative Medicine (M.J.D.), University of Oxford, United Kingdom.,Department of Cardiology, Oxford University NHS Hospitals Trust, United Kingdom (H.W., M.J.D.).,Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan (M.J.D.)
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Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare congenital arrhythmogenic disorder induced by physical or emotional stress. It mainly affects children and younger adults and is characterized by rapid polymorphic and bidirectional ventricular tachycardia. Symptoms can include dizziness, palpitations, and presyncope, which may progress to syncope, hypotonia, convulsive movements, and sudden cardiac death. CPVT is the result of perturbations in Ca ion handling in the sarcoplasmic reticulum of cardiac myocytes. Mutations in the cardiac ryanodine receptor gene and the calsequestrin isoform 2 gene are most commonly seen in familial CPVT patients. Under catecholaminergic stimulation, either mutation can result in an excess Ca load during diastole resulting in delayed after depolarization and subsequent arrhythmogenesis. The current first-line treatment for CPVT is β-blocker therapy. Other therapeutic interventions that can be used in conjunction with β-blockers include moderate exercise training, flecainide, left cardiac sympathetic denervation, and implantable cardioverter-defibrillators. Several potential therapeutic interventions, including verapamil, dantrolene, JTV519, and gene therapy, are also discussed.
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40
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Connell P, Word TA, Wehrens XHT. Targeting pathological leak of ryanodine receptors: preclinical progress and the potential impact on treatments for cardiac arrhythmias and heart failure. Expert Opin Ther Targets 2020; 24:25-36. [PMID: 31869254 DOI: 10.1080/14728222.2020.1708326] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Introduction: Type-2 ryanodine receptor (RyR2) located on the sarcoplasmic reticulum initiate systolic Ca2+ transients within cardiomyocytes. Proper functioning of RyR2 is therefore crucial to the timing and force generated by cardiomyocytes within a healthy heart. Improper intracellular Ca2+ handing secondary to RyR2 dysfunction is associated with a variety of cardiac pathologies including catecholaminergic polymorphic ventricular tachycardia (CPVT), atrial fibrillation (AF), and heart failure (HF). Thus, RyR2 and its associated accessory proteins provide promising drug targets to scientists developing therapeutics for a variety of cardiac pathologies.Areas covered: In this article, we review the role of RyR2 in a variety of cardiac pathologies. We performed a literature search utilizing PubMed and MEDLINE as well as reviewed registries of trials from clinicaltrials.gov from 2010 to 2019 for novel therapeutic approaches that address the cellular mechanisms underlying CPVT, AF, and HF by specifically targeting defective RyR2 channels.Expert opinion: The negative impact of cardiac dysfunction on human health and medical economics are major motivating factors for establishing new and effective therapeutic approaches. Focusing on directly impacting the molecular mechanisms underlying defective Ca2+ handling by RyR2 in HF and arrhythmia has great potential to be translated into novel and innovative therapies.
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Affiliation(s)
- Patrick Connell
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Departments of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Tarah A Word
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Departments of Pediatrics, Baylor College of Medicine, Houston, TX, USA.,Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA.,Medicine (Cardiology, Baylor College of Medicine, Houston, TX, USA.,Neuroscience, Baylor College of Medicine, Houston, TX, USA.,Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA
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41
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Pölönen RP, Swan H, Aalto-Setälä K. Mutation-specific differences in arrhythmias and drug responses in CPVT patients: simultaneous patch clamp and video imaging of iPSC derived cardiomyocytes. Mol Biol Rep 2019; 47:1067-1077. [PMID: 31786768 DOI: 10.1007/s11033-019-05201-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/21/2019] [Indexed: 12/26/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac disease characterized by arrhythmias under adrenergic stress. Mutations in the cardiac ryanodine receptor (RYR2) are the leading cause for CPVT. We characterized electrophysiological properties of CPVT patient-specific induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying different mutations in RYR2 and evaluated effects of carvedilol and flecainide on action potential (AP) and contractile properties of hiPSC-CMs. iPSC-CMs were generated from skin biopsies of CPVT patients carrying exon 3 deletion (E3D) and L4115F mutation in RYR2. APs and contractile movement were recorded simultaneously from the same hiPSC-CMs. Differences in AP properties of ventricular like CMs were seen in CPVT and control CMs: APD90 of both E3D (n = 20) and L4115F (n = 25) CPVT CMs was shorter than in control CMs (n = 15). E3D-CPVT CMs had shortest AP duration, lowest AP amplitude, upstroke velocity and more depolarized diastolic potential than controls. Adrenaline had positive and carvedilol and flecainide negative chronotropic effect in all hiPSC CMs. CPVT CMs had increased amount of delayed after depolarizations (DADs) and early after depolarizations (EADs) after adrenaline exposure. E3D CPVT CMs had the most DADs, EADs, and tachyarrhythmia. Discordant negatively coupled alternans was seen in L4115F CPVT CMs. Carvedilol cured almost all arrhythmias in L4115F CPVT CMs. Both drugs decreased contraction amplitude in all hiPSC CMs. E3D CPVT CMs have electrophysiological properties, which render them more prone to arrhythmias. iPSC-CMs provide a unique platform for disease modeling and drug screening for CPVT. Combining electrophysiological measurements, we can gain deeper insight into mechanisms of arrhythmias.
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Affiliation(s)
- R P Pölönen
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Arvo2 D441, 33520, Tampere, Finland.
| | - H Swan
- Helsinki University Hospital and Helsinki University, PO Box 340, 00029, Helsinki, Finland
| | - K Aalto-Setälä
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Arvo2 D441, 33520, Tampere, Finland
- Heart Center, Tampere University Hospital, Arvo Ylpön katu 34, Arvo2 D437, 33520, Tampere, Finland
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42
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Dries E, Santiago DJ, Gilbert G, Lenaerts I, Vandenberk B, Nagaraju CK, Johnson DM, Holemans P, Roderick HL, Macquaide N, Claus P, Sipido KR. Hyperactive ryanodine receptors in human heart failure and ischaemic cardiomyopathy reside outside of couplons. Cardiovasc Res 2019; 114:1512-1524. [PMID: 29668881 PMCID: PMC6106102 DOI: 10.1093/cvr/cvy088] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 04/12/2018] [Indexed: 12/26/2022] Open
Abstract
Aims In ventricular myocytes from humans and large mammals, the transverse and axial tubular system (TATS) network is less extensive than in rodents with consequently a greater proportion of ryanodine receptors (RyRs) not coupled to this membrane system. TATS remodelling in heart failure (HF) and after myocardial infarction (MI) increases the fraction of non-coupled RyRs. Here we investigate whether this remodelling alters the activity of coupled and non-coupled RyR sub-populations through changes in local signalling. We study myocytes from patients with end-stage HF, compared with non-failing (non-HF), and myocytes from pigs with MI and reduced left ventricular (LV) function, compared with sham intervention (SHAM). Methods and results Single LV myocytes for functional studies were isolated according to standard protocols. Immunofluorescent staining visualized organization of TATS and RyRs. Ca2+ was measured by confocal imaging (fluo-4 as indicator) and using whole-cell patch-clamp (37°C). Spontaneous Ca2+ release events, Ca2+ sparks, as a readout for RyR activity were recorded during a 15 s period following conditioning stimulation at 2 Hz. Sparks were assigned to cell regions categorized as coupled or non-coupled sites according to a previously developed method. Human HF myocytes had more non-coupled sites and these had more spontaneous activity than in non-HF. Hyperactivity of these non-coupled RyRs was reduced by Ca2+/calmodulin-dependent kinase II (CaMKII) inhibition. Myocytes from MI pigs had similar changes compared with SHAM controls as seen in human HF myocytes. As well as by CaMKII inhibition, in MI, the increased activity of non-coupled sites was inhibited by mitochondrial reactive oxygen species (mito-ROS) scavenging. Under adrenergic stimulation, Ca2+ waves were more frequent and originated at non-coupled sites, generating larger Na+/Ca2+ exchange currents in MI than in SHAM. Inhibition of CaMKII or mito-ROS scavenging reduced spontaneous Ca2+ waves, and improved excitation–contraction coupling. Conclusions In HF and after MI, RyR microdomain re-organization enhances spontaneous Ca2+ release at non-coupled sites in a manner dependent on CaMKII activation and mito-ROS production. This specific modulation generates a substrate for arrhythmia that appears to be responsive to selective pharmacologic modulation.
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Affiliation(s)
- Eef Dries
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Demetrio J Santiago
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Guillaume Gilbert
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Ilse Lenaerts
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Bert Vandenberk
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Chandan K Nagaraju
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Daniel M Johnson
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Patricia Holemans
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - H Llewelyn Roderick
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Niall Macquaide
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Piet Claus
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Karin R Sipido
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
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43
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Coppini R, Ferrantini C, Pioner JM, Santini L, Wang ZJ, Palandri C, Scardigli M, Vitale G, Sacconi L, Stefàno P, Flink L, Riedy K, Pavone FS, Cerbai E, Poggesi C, Mugelli A, Bueno-Orovio A, Olivotto I, Sherrid MV. Electrophysiological and Contractile Effects of Disopyramide in Patients With Obstructive Hypertrophic Cardiomyopathy: A Translational Study. JACC Basic Transl Sci 2019; 4:795-813. [PMID: 31998849 PMCID: PMC6978554 DOI: 10.1016/j.jacbts.2019.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/07/2019] [Accepted: 06/07/2019] [Indexed: 01/26/2023]
Abstract
In patients with HCM and symptomatic LVOT-obstruction, first treatment with disopyramide leads to a marked reduction of LVOT gradients, with a slight decrease of resting ejection fraction and a modest increase of corrected QT interval, highlighting high efficacy and safety. In single cardiomyocytes and intact trabeculae from surgical samples of patients with obstructive HCM, in vitro treatment with 5 μmol/l disopyramide lowered force and Ca2+ transients while reducing action potential duration and the rate of arrhythmic afterdepolarizations. These effects are mediated by the combined inhibition of peak and late Na+ currents, L-type Ca2+ current, delayed-rectifier K+ current, and ryanodine receptors. In addition to the negative inotropic effect of disopyramide, in vitro results suggest additional antiarrhythmic actions.
Disopyramide is effective and safe in patients with obstructive hypertrophic cardiomyopathy. However, its cellular and molecular mechanisms of action are unknown. We tested disopyramide in cardiomyocytes from the septum of surgical myectomy patients: disopyramide inhibits multiple ion channels, leading to lower Ca transients and force, and shortens action potentials, thus reducing cellular arrhythmias. The electrophysiological profile of disopyramide explains the efficient reduction of outflow gradients but also the limited prolongation of the QT interval and the absence of arrhythmic side effects observed in 39 disopyramide-treated patients. In conclusion, our results support the idea that disopyramide is safe for outpatient use in obstructive patients.
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Key Words
- AP, action potential
- DAD, delayed afterdepolarization
- EAD, early afterdepolarization
- ECG, electrocardiography
- HCM, hypertrophic cardiomyopathy
- ICa-L, L-type Ca current
- IK, delayed-rectifier K current
- INaL, late Na current
- LVOT, left ventricular outflow tract
- NCX, Na+/Ca2+ exchanger
- QT interval
- RyR, ryanodine receptor
- SR, sarcoplasmic reticulum
- action potentials
- arrhythmias
- diastolic dysfunction
- hERG, human ether-à-go-go-related gene
- hypertrophic cardiomyopathy
- pCa, Ca activation level
- safety
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Affiliation(s)
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Josè Manuel Pioner
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Lorenzo Santini
- Department NeuroFarBa, University of Florence, Florence, Italy
| | - Zhinuo J Wang
- Department of Computer Sciences, University of Oxford, Oxford, United Kingdom
| | - Chiara Palandri
- Department NeuroFarBa, University of Florence, Florence, Italy
| | - Marina Scardigli
- European Laboratory for Nonlinear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy and National Institute of Optics, National Research Council, Florence, Italy
| | - Giulia Vitale
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Leonardo Sacconi
- European Laboratory for Nonlinear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy and National Institute of Optics, National Research Council, Florence, Italy
| | - Pierluigi Stefàno
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Laura Flink
- Division of Cardiology, San Francisco Veterans Affairs Medical Center and University of California-San Francisco, San Francisco, California
| | - Katherine Riedy
- Hypertrophic Cardiomyopathy Program, New York University Langone Health, New York, New York
| | - Francesco Saverio Pavone
- European Laboratory for Nonlinear Spectroscopy (LENS), University of Florence, Sesto Fiorentino, Italy and National Institute of Optics, National Research Council, Florence, Italy
| | | | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | | | | | - Iacopo Olivotto
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Mark V Sherrid
- Hypertrophic Cardiomyopathy Program, New York University Langone Health, New York, New York
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Hwang HS, Baldo MP, Rodriguez JP, Faggioni M, Knollmann BC. Efficacy of Flecainide in Catecholaminergic Polymorphic Ventricular Tachycardia Is Mutation-Independent but Reduced by Calcium Overload. Front Physiol 2019; 10:992. [PMID: 31456692 PMCID: PMC6701460 DOI: 10.3389/fphys.2019.00992] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 07/18/2019] [Indexed: 11/22/2022] Open
Abstract
Background The dual Na+ and cardiac Ca2+-release channel inhibitor, Flecainide (FLEC) is effective in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), a disease caused by mutations in cardiac Ca2+-release channels (RyR2), calsequestrin (Casq2), or calmodulin. FLEC suppresses spontaneous Ca2+ waves in Casq2-knockout (Casq2−/−) cardiomyocytes, a CPVT model. However, a report failed to find FLEC efficacy against Ca2+ waves in another CPVT model, RyR2-R4496C heterozygous mice (RyR2R4496C+/−), raising the possibility that FLEC efficacy may be mutation dependent. Objective To address this controversy, we compared FLEC in Casq2−/− and RyR2R4496C+/− cardiomyocytes and mice under identical conditions. Methods After 30 min exposure to FLEC (6 μM) or vehicle (VEH), spontaneous Ca2+ waves were quantified during a 40 s pause after 1 Hz pacing train in the presence of isoproterenol (ISO, 1 μM). FLEC efficacy was also tested in vivo using a low dose (LOW: 3 mg/kg ISO + 60 mg/kg caffeine) or a high dose catecholamine challenge (HIGH: 3 mg/kg ISO + 120 mg/kg caffeine). Results In cardiomyocytes, FLEC efficacy was dependent on extracellular [Ca2+]. At 2 mM [Ca2+], only Casq2−/− myocytes exhibited Ca2+ waves, which were strongly suppressed by FLEC. At 3 mM [Ca2+] both groups exhibited Ca2+ waves that were suppressed by FLEC. At 4 mM [Ca2+], FLEC no longer suppressed Ca2+ waves in both groups. Analogous to the results in myocytes, RyR2R4496C+/− mice (n = 12) had significantly lower arrhythmia scores than Casq2−/− mice (n = 9), but the pattern of FLEC efficacy was similar in both groups (i.e., reduced FLEC efficacy after HIGH dose catecholamine challenge). Conclusion FLEC inhibits Ca2+ waves in RyR2R4496C+/− cardiomyocytes, indicating that RyR2 channel block by FLEC is not mutation-specific. However, FLEC efficacy is reduced by Ca2+ overload in vitro or by high dose catecholamine challenge in vivo, which could explain conflicting literature reports.
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Affiliation(s)
- Hyun Seok Hwang
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, United States.,Division of Clinical Pharmacology, Oates Institute for Experimental Therapeutics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Marcelo P Baldo
- Division of Clinical Pharmacology, Oates Institute for Experimental Therapeutics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Jose Pindado Rodriguez
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, United States
| | - Michela Faggioni
- Division of Clinical Pharmacology, Oates Institute for Experimental Therapeutics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Oates Institute for Experimental Therapeutics, Vanderbilt University School of Medicine, Nashville, TN, United States
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45
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Baltogiannis GG, Lysitsas DN, di Giovanni G, Ciconte G, Sieira J, Conte G, Kolettis TM, Chierchia GB, de Asmundis C, Brugada P. CPVT: Arrhythmogenesis, Therapeutic Management, and Future Perspectives. A Brief Review of the Literature. Front Cardiovasc Med 2019; 6:92. [PMID: 31380394 PMCID: PMC6644488 DOI: 10.3389/fcvm.2019.00092] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/21/2019] [Indexed: 11/25/2022] Open
Abstract
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a primary electrical disease characterized by a normal resting electrocardiogram and induction of malignant arrhythmias during adrenergic stress leading to syncope or sudden cardiac death (SCD). CPVT is caused by mutations in the cardiac ryanodine receptor (RyR2) or in the sarcoplasmic reticulum protein calsequestrin 2 genes (CASQ2). The RyR2 mutations are responsible for the autosomal dominant form of CPVT, while CASQ2 mutations are rare and account for the recessive form. These mutations cause a substantial inballance in the homeostasis of intracellular calcium resulting in polymorphic ventricular tachycardia through triggered activity. Beta blockers were for years the cornerstone of therapy in these patients. Sodium channel blockers, especially flecainide, have an additive role in those not responding in beta blockade. Implantation of defibrillators needs a meticulous evaluation since inappropriate shocks may lead to electrical storm. Finally, cardiac sympathetic denervation might also be an alternative therapeutic option. Early identification and risk stratification is of major importance in patients with CPVT. The aim of the present review is to present the arrhythmogenic mechanisms of the disease, the current therapies applied and potential future perspectives.
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Affiliation(s)
- Giannis G Baltogiannis
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium.,St. Luke's Hospital Thessaloniki, Thessaloniki, Greece
| | | | | | - Giuseppe Ciconte
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
| | - Juan Sieira
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
| | - Giulio Conte
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
| | | | | | | | - Pedro Brugada
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
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46
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Unnatural verticilide enantiomer inhibits type 2 ryanodine receptor-mediated calcium leak and is antiarrhythmic. Proc Natl Acad Sci U S A 2019; 116:4810-4815. [PMID: 30792355 DOI: 10.1073/pnas.1816685116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ca2+ leak via ryanodine receptor type 2 (RyR2) can cause potentially fatal arrhythmias in a variety of heart diseases and has also been implicated in neurodegenerative and seizure disorders, making RyR2 an attractive therapeutic target for drug development. Here we synthesized and investigated the fungal natural product and known insect RyR antagonist (-)-verticilide and several congeners to determine their activity against mammalian RyR2. Although the cyclooligomeric depsipeptide natural product (-)-verticilide had no effect, its nonnatural enantiomer [ent-(+)-verticilide] significantly reduced RyR2-mediated spontaneous Ca2+ leak both in cardiomyocytes from wild-type mouse and from a gene-targeted mouse model of Ca2+ leak-induced arrhythmias (Casq2-/-). ent-(+)-verticilide selectively inhibited RyR2-mediated Ca2+ leak and exhibited higher potency and a distinct mechanism of action compared with the pan-RyR inhibitors dantrolene and tetracaine and the antiarrhythmic drug flecainide. ent-(+)-verticilide prevented arrhythmogenic membrane depolarizations in cardiomyocytes without significant effects on the cardiac action potential and attenuated ventricular arrhythmia in catecholamine-challenged Casq2-/- mice. These findings indicate that ent-(+)-verticilide is a potent and selective inhibitor of RyR2-mediated diastolic Ca2+ leak, making it a molecular tool to investigate the therapeutic potential of targeting RyR2 hyperactivity in heart and brain pathologies. The enantiomer-specific activity and straightforward chemical synthesis of (unnatural) ent-(+)-verticilide provides a compelling argument to prioritize ent-natural product synthesis. Despite their general absence in nature, the enantiomers of natural products may harbor unprecedented activity, thereby leading to new scaffolds for probe and therapeutic development.
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47
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Potenza DM, Janicek R, Fernandez-Tenorio M, Camors E, Ramos-Mondragón R, Valdivia HH, Niggli E. Phosphorylation of the ryanodine receptor 2 at serine 2030 is required for a complete β-adrenergic response. J Gen Physiol 2018; 151:131-145. [PMID: 30541771 PMCID: PMC6363414 DOI: 10.1085/jgp.201812155] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/12/2018] [Accepted: 10/22/2018] [Indexed: 11/20/2022] Open
Abstract
Phosphorylation is thought to play a role in modulation of the ryanodine receptor 2 channel. Using a S2030A knock-in mouse model, Potenza et al. reveal that phosphorylation of RyR2-S2030 mediates channel regulation during the β-adrenergic response. During physical exercise or stress, the sympathetic system stimulates cardiac contractility via β-adrenergic receptor (β-AR) activation, resulting in protein kinase A (PKA)–mediated phosphorylation of the cardiac ryanodine receptor RyR2. PKA-dependent “hyperphosphorylation” of the RyR2 channel has been proposed as a major impairment that contributes to progression of heart failure. However, the sites of PKA phosphorylation and their phosphorylation status in cardiac diseases are not well defined. Among the known RyR2 phosphorylation sites, serine 2030 (S2030) remains highly controversial as a site of functional impact. We examined the contribution of RyR2-S2030 to Ca2+ signaling and excitation–contraction coupling (ECC) in a transgenic mouse with an ablated RyR2-S2030 phosphorylation site (RyR2-S2030A+/+). We assessed ECC gain by using whole-cell patch–clamp recordings and confocal Ca2+ imaging during β-ARs stimulation with isoproterenol (Iso) and consistent SR Ca2+ loading and L-type Ca2+ current (ICa) triggering. Under these conditions, ECC gain is diminished in mutant compared with WT cardiomyocytes. Resting Ca2+ spark frequency (CaSpF) with Iso is also reduced by mutation of S2030. In permeabilized cells, when SR Ca2+ pump activity is kept constant (using 2D12 antibody against phospholamban), cAMP does not change CaSpF in S2030A+/+ myocytes. Using Ca2+ spark recovery analysis, we found that mutant RyR Ca2+ sensitivity is not enhanced by Iso application, contrary to WT RyRs. Furthermore, ablation of RyR2-S2030 prevents acceleration of Ca2+ waves and increases latency to the first spontaneous Ca2+ release after a train of stimulations during Iso treatment. Together, these results suggest that phosphorylation at S2030 may represent an important step in the modulation of RyR2 activity during β-adrenergic stimulation and a potential target for the development of new antiarrhythmic drugs.
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Affiliation(s)
| | | | | | - Emmanuel Camors
- Center for Arrhythmia Research, Department of Medicine, University of Michigan, Ann Arbor, MI
| | - Roberto Ramos-Mondragón
- Center for Arrhythmia Research, Department of Medicine, University of Michigan, Ann Arbor, MI
| | - Héctor H Valdivia
- Department of Medicine, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, WI.,Center for Arrhythmia Research, Department of Medicine, University of Michigan, Ann Arbor, MI
| | - Ernst Niggli
- Department of Physiology, University of Bern, Bern, Switzerland
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48
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Voigt N, Lehnart SE. Ryanodine receptor dysfunction and the resolution revolution: how Nobel Prize-winning techniques transform cardiovascular research. Cardiovasc Res 2018; 114:e106-e109. [PMID: 30476015 DOI: 10.1093/cvr/cvy235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Niels Voigt
- Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research) site Göttingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research) site Göttingen, Germany.,BioMET, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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49
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Levin MD, Saitta SC, Gripp KW, Wenger TL, Ganesh J, Kalish JM, Epstein MR, Smith R, Czosek RJ, Ware SM, Goldenberg P, Myers A, Chatfield KC, Gillespie MJ, Zackai EH, Lin AE. Nonreentrant atrial tachycardia occurs independently of hypertrophic cardiomyopathy in RASopathy patients. Am J Med Genet A 2018; 176:1711-1722. [PMID: 30055033 DOI: 10.1002/ajmg.a.38854] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/04/2018] [Accepted: 05/01/2018] [Indexed: 11/12/2022]
Abstract
Multifocal atrial tachycardia (MAT) has a well-known association with Costello syndrome, but is rarely described with related RAS/MAPK pathway disorders (RASopathies). We report 11 patients with RASopathies (Costello, Noonan, and Noonan syndrome with multiple lentigines [formerly LEOPARD syndrome]) and nonreentrant atrial tachycardias (MAT and ectopic atrial tachycardia) demonstrating overlap in cardiac arrhythmia phenotype. Similar overlap is seen in RASopathies with respect to skeletal, musculoskeletal and cutaneous abnormalities, dysmorphic facial features, and neurodevelopmental deficits. Nonreentrant atrial tachycardias may cause cardiac compromise if sinus rhythm is not restored expeditiously. Typical first-line supraventricular tachycardia anti-arrhythmics (propranolol and digoxin) were generally not effective in restoring or maintaining sinus rhythm in this cohort, while flecainide or amiodarone alone or in concert with propranolol were effective anti-arrhythmic agents for acute and chronic use. Atrial tachycardia resolved in all patients. However, a 4-month-old boy from the cohort was found asystolic (with concurrent cellulitis) and a second patient underwent cardiac transplant for heart failure complicated by recalcitrant atrial arrhythmia. While propranolol alone frequently failed to convert or maintain sinus rhythm, fleccainide or amiodarone, occasionally in combination with propranolol, was effective for RASopathy patient treatment for nonreentrant atrial arrhythmia. Our analysis shows that RASopathy patients may have nonreentrant atrial tachycardia with and without associated cardiac hypertrophy. While nonreentrant arrhythmia has been traditionally associated with Costello syndrome, this work provides an expanded view of RASopathy cardiac arrhythmia phenotype as we demonstrate mutant proteins throughout this signaling pathway can also give rise to ectopic and/or MAT.
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Affiliation(s)
- Mark D Levin
- Division of Cardiology, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Sulagna C Saitta
- Division of Genomic Medicine, Department of Pathology, Children's Hospital Los Angeles and Keck-USC School of Medicine, Los Angeles, California
| | - Karen W Gripp
- Division of Medical Genetics, A. I. du Pont Hospital for Children, Wilmington, Delaware
| | - Tara L Wenger
- Division of Craniofacial Medicine, Seattle Children's Hospital, Seattle, Washington
| | - Jaya Ganesh
- Department of Pediatrics, Cooper Medical School at Rowan University, Camden, New Jersey
| | - Jennifer M Kalish
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Michael R Epstein
- Division of Cardiology, Department of Pediatrics, Maine Medical Center, Portland, Maine
| | - Rosemarie Smith
- Division of Genetics, Department of Pediatrics, Maine Medical Center, Portland, Maine
| | - Richard J Czosek
- The Heart Institute, Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Stephanie M Ware
- Departments of Pediatrics and Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Paula Goldenberg
- Genetics Unit, MassGeneral Hospital for Children, Boston, Massachusetts
| | - Angela Myers
- Division of Medical Genetics, Sanford Health, Sioux Falls, South Dakota
| | - Kathryn C Chatfield
- Department of Pediatrics, Section of Cardiology, University of Colorado School of Medicine, Aurora, Colorado
| | - Matthew J Gillespie
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Elaine H Zackai
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Angela E Lin
- Genetics Unit, MassGeneral Hospital for Children, Boston, Massachusetts
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50
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Woulfe KC, Wilson CE, Nau S, Chau S, Phillips EK, Zang S, Tompkins C, Sucharov CC, Miyamoto SD, Stauffer BL. Acute isoproterenol leads to age-dependent arrhythmogenesis in guinea pigs. Am J Physiol Heart Circ Physiol 2018; 315:H1051-H1062. [PMID: 30028197 DOI: 10.1152/ajpheart.00061.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sudden cardiac death from ventricular arrhythmias is more common in adult patients with with heart failure compared with pediatric patients with heart failure. We identified age-specific differences in arrhythmogenesis using a guinea pig model of acute β-adrenergic stimulation. Young and adult guinea pigs were exposed to the β-adrenergic agonist isoproterenol (ISO; 0.7 mg/kg) for 30 min in the absence or presence of flecainide (20 mg/kg), an antiarrhythmic that blocks Na+ and ryanodine channels. Implanted cardiac monitors (Reveal LINQ, Medtronic) were used to monitor heart rhythm. Alterations in phosphorylation and oxidation of ryanodine receptor 2 (RyR2) were measured in left ventricular tissue. There were age-specific differences in arrhythmogenesis and sudden death associated with acute β-adrenergic stimulation in guinea pigs. Young and adult guinea pigs developed arrhythmias in response to ISO; however, adult animals developed significantly more premature ventricular contractions and experienced higher arrhythmia-related mortality than young guinea pigs treated with ISO. Although there were no significant differences in the phosphorylation of left ventricular RyR2 between young and adult guinea pigs, adult guinea pigs exposed to acute ISO had significantly more oxidation of RyR2. Flecainide treatment significantly improved survival and decreased the number of premature ventricular contractions in young and adult animals in association with lower RyR2 oxidation. Adult guinea pigs had a greater propensity to develop arrhythmias and suffer sudden death than young guinea pigs when acutely exposed to ISO. This was associated with higher oxidation of RyR2. The incidence of sudden death can be rescued with flecainide treatment, which decreases RyR2 oxidation. NEW & NOTEWORTHY Clinically, adult patients with heart failure are more likely to develop arrhythmias and sudden death than pediatric patients with heart failure. In the present study, older guinea pigs also showed a greater propensity to arrhythmias and sudden death than young guinea pigs when acutely exposed to isoproterenol. Although there are well-described age-related cardiac structural changes that predispose patients to arrhythmogenesis, the present data suggest contributions from dynamic changes in cellular signaling also play an important role in arrhythmogenesis.
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Affiliation(s)
- Kathleen C Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Cortney E Wilson
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Shane Nau
- University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Sarah Chau
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Elisabeth K Phillips
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Shulun Zang
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Christine Tompkins
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Carmen C Sucharov
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Shelley D Miyamoto
- Division of Cardiology, Department of Pediatrics, University of Colorado Denver School of Medicine and Children's Hospital Colorado , Aurora, Colorado
| | - Brian L Stauffer
- Division of Cardiology, Department of Medicine, University of Colorado Denver School of Medicine , Aurora, Colorado.,Division of Cardiology, Department of Medicine, Denver Health and Hospital Authority , Denver, Colorado
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