1
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Jimenez-Vazquez EN, Arad M, Macías Á, Vera-Pedrosa ML, Cruz FM, Gutierrez LK, Cuttitta AJ, Monteiro da Rocha A, Herron TJ, Ponce-Balbuena D, Guerrero-Serna G, Binah O, Michele DE, Jalife J. SNTA1 gene rescues ion channel function and is antiarrhythmic in cardiomyocytes derived from induced pluripotent stem cells from muscular dystrophy patients. eLife 2022; 11:e76576. [PMID: 35762211 PMCID: PMC9239678 DOI: 10.7554/elife.76576] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 06/07/2022] [Indexed: 01/10/2023] Open
Abstract
Background Patients with cardiomyopathy of Duchenne Muscular Dystrophy (DMD) are at risk of developing life-threatening arrhythmias, but the mechanisms are unknown. We aimed to determine the role of ion channels controlling cardiac excitability in the mechanisms of arrhythmias in DMD patients. Methods To test whether dystrophin mutations lead to defective cardiac NaV1.5-Kir2.1 channelosomes and arrhythmias, we generated iPSC-CMs from two hemizygous DMD males, a heterozygous female, and two unrelated control males. We conducted studies including confocal microscopy, protein expression analysis, patch-clamping, non-viral piggy-bac gene expression, optical mapping and contractility assays. Results Two patients had abnormal ECGs with frequent runs of ventricular tachycardia. iPSC-CMs from all DMD patients showed abnormal action potential profiles, slowed conduction velocities, and reduced sodium (INa) and inward rectifier potassium (IK1) currents. Membrane NaV1.5 and Kir2.1 protein levels were reduced in hemizygous DMD iPSC-CMs but not in heterozygous iPSC-CMs. Remarkably, transfecting just one component of the dystrophin protein complex (α1-syntrophin) in hemizygous iPSC-CMs from one patient restored channelosome function, INa and IK1 densities, and action potential profile in single cells. In addition, α1-syntrophin expression restored impulse conduction and contractility and prevented reentrant arrhythmias in hiPSC-CM monolayers. Conclusions We provide the first demonstration that iPSC-CMs reprogrammed from skin fibroblasts of DMD patients with cardiomyopathy have a dysfunction of the NaV1.5-Kir2.1 channelosome, with consequent reduction of cardiac excitability and conduction. Altogether, iPSC-CMs from patients with DMD cardiomyopathy have a NaV1.5-Kir2.1 channelosome dysfunction, which can be rescued by the scaffolding protein α1-syntrophin to restore excitability and prevent arrhythmias. Funding Supported by National Institutes of Health R01 HL122352 grant; 'la Caixa' Banking Foundation (HR18-00304); Fundación La Marató TV3: Ayudas a la investigación en enfermedades raras 2020 (LA MARATO-2020); Instituto de Salud Carlos III/FEDER/FSE; Horizon 2020 - Research and Innovation Framework Programme GA-965286 to JJ; the CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN) and the Pro CNIC Foundation), and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/10.13039/501100011033). American Heart Association postdoctoral fellowship 19POST34380706s to JVEN. Israel Science Foundation to OB and MA [824/19]. Rappaport grant [01012020RI]; and Niedersachsen Foundation [ZN3452] to OB; US-Israel Binational Science Foundation (BSF) to OB and TH [2019039]; Dr. Bernard Lublin Donation to OB; and The Duchenne Parent Project Netherlands (DPPNL 2029771) to OB. National Institutes of Health R01 AR068428 to DM and US-Israel Binational Science Foundation Grant [2013032] to DM and OB.
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Affiliation(s)
- Eric N Jimenez-Vazquez
- Department of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of MichiganAnn ArborUnited States
| | - Michael Arad
- Leviev Heart Center, Sheba Medical Center, Tel Hashomer, and Tel Aviv UniversityTel AvivIsrael
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV)MadridSpain
| | - Maria L Vera-Pedrosa
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV)MadridSpain
| | - Francisco Miguel Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV)MadridSpain
| | - Lilian K Gutierrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV)MadridSpain
| | - Ashley J Cuttitta
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
| | - André Monteiro da Rocha
- Department of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of MichiganAnn ArborUnited States
| | - Todd J Herron
- Department of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of MichiganAnn ArborUnited States
| | - Daniela Ponce-Balbuena
- Department of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of MichiganAnn ArborUnited States
| | - Guadalupe Guerrero-Serna
- Department of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of MichiganAnn ArborUnited States
| | - Ofer Binah
- Department of Physiology, Biophysics and Systems Biology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of TechnologyHaifaIsrael
| | - Daniel E Michele
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
| | - José Jalife
- Department of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of MichiganAnn ArborUnited States
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV)MadridSpain
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
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2
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Aguayo-Ortiz R, Creech J, Jiménez-Vázquez EN, Guerrero-Serna G, Wang N, da Rocha AM, Herron TJ, Espinoza-Fonseca LM. A multiscale approach for bridging the gap between potency, efficacy, and safety of small molecules directed at membrane proteins. Sci Rep 2021; 11:16580. [PMID: 34400719 PMCID: PMC8368179 DOI: 10.1038/s41598-021-96217-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/06/2021] [Indexed: 01/17/2023] Open
Abstract
Membrane proteins constitute a substantial fraction of the human proteome, thus representing a vast source of therapeutic drug targets. Indeed, newly devised technologies now allow targeting "undruggable" regions of membrane proteins to modulate protein function in the cell. Despite the advances in technology, the rapid translation of basic science discoveries into potential drug candidates targeting transmembrane protein domains remains challenging. We address this issue by harmonizing single molecule-based and ensemble-based atomistic simulations of ligand-membrane interactions with patient-derived induced pluripotent stem cell (iPSC)-based experiments to gain insights into drug delivery, cellular efficacy, and safety of molecules directed at membrane proteins. In this study, we interrogated the pharmacological activation of the cardiac Ca2+ pump (Sarcoplasmic reticulum Ca2+-ATPase, SERCA2a) in human iPSC-derived cardiac cells as a proof-of-concept model. The combined computational-experimental approach serves as a platform to explain the differences in the cell-based activity of candidates with similar functional profiles, thus streamlining the identification of drug-like candidates that directly target SERCA2a activation in human cardiac cells. Systematic cell-based studies further showed that a direct SERCA2a activator does not induce cardiotoxic pro-arrhythmogenic events in human cardiac cells, demonstrating that pharmacological stimulation of SERCA2a activity is a safe therapeutic approach targeting the heart. Overall, this novel multiscale platform encompasses organ-specific drug potency, efficacy, and safety, and opens new avenues to accelerate the bench-to-patient research aimed at designing effective therapies directed at membrane protein domains.
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Affiliation(s)
- Rodrigo Aguayo-Ortiz
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, 04510, Mexico, Mexico
| | - Jeffery Creech
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
- Frankel Cardiovascular Regeneration Core Laboratory, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eric N Jiménez-Vázquez
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Guadalupe Guerrero-Serna
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nulang Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Andre Monteiro da Rocha
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
- Frankel Cardiovascular Regeneration Core Laboratory, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Todd J Herron
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA
- Frankel Cardiovascular Regeneration Core Laboratory, University of Michigan, Ann Arbor, MI, 48109, USA
- CARTOX, Inc., 56655 Grand River Ave., PO Box 304, New Hudson, MI, 48165, USA
| | - L Michel Espinoza-Fonseca
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, 48109, USA.
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3
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Lugenbiel P, Govorov K, Syren P, Rahm AK, Wieder T, Wunsch M, Weiberg N, Manolova E, Gramlich D, Rivinius R, Finke D, Lehmann LH, Schweizer PA, Frank D, El Tahry FA, Bruehl C, Heimberger T, Sandke S, Weis T, Most P, Schmack B, Ruhparwar A, Karck M, Frey N, Katus HA, Thomas D. Epigenetic regulation of cardiac electrophysiology in atrial fibrillation: HDAC2 determines action potential duration and suppresses NRSF in cardiomyocytes. Basic Res Cardiol 2021; 116:13. [PMID: 33630168 DOI: 10.1007/s00395-021-00855-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/18/2021] [Indexed: 01/03/2023]
Abstract
Atrial fibrillation (AF) is associated with electrical remodeling, leading to cellular electrophysiological dysfunction and arrhythmia perpetuation. Emerging evidence suggests a key role for epigenetic mechanisms in the regulation of ion channel expression. Histone deacetylases (HDACs) control gene expression through deacetylation of histone proteins. We hypothesized that class I HDACs in complex with neuron-restrictive silencer factor (NRSF) determine atrial K+ channel expression. AF was characterized by reduced atrial HDAC2 mRNA levels and upregulation of NRSF in humans and in a pig model, with regional differences between right and left atrium. In vitro studies revealed inverse regulation of Hdac2 and Nrsf in HL-1 atrial myocytes. A direct association of HDAC2 with active regulatory elements of cardiac K+ channels was revealed by chromatin immunoprecipitation. Specific knock-down of Hdac2 and Nrsf induced alterations of K+ channel expression. Hdac2 knock-down resulted in prolongation of action potential duration (APD) in neonatal rat cardiomyocytes, whereas inactivation of Nrsf induced APD shortening. Potential AF-related triggers were recapitulated by experimental tachypacing and mechanical stretch, respectively, and exerted differential effects on the expression of class I HDACs and K+ channels in cardiomyocytes. In conclusion, HDAC2 and NRSF contribute to AF-associated remodeling of APD and K+ channel expression in cardiomyocytes via direct interaction with regulatory chromatin regions. Specific modulation of these factors may provide a starting point for the development of more individualized treatment options for atrial fibrillation.
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Affiliation(s)
- Patrick Lugenbiel
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
| | - Katharina Govorov
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
| | - Pascal Syren
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
| | - Ann-Kathrin Rahm
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Teresa Wieder
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
| | - Maximilian Wunsch
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Nadine Weiberg
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
| | - Emili Manolova
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
| | - Dominik Gramlich
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Rasmus Rivinius
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Daniel Finke
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- Department of Molecular Cardiology and Epigenetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Lorenz H Lehmann
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- Department of Molecular Cardiology and Epigenetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Patrick A Schweizer
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Derk Frank
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Kiel, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Fadwa A El Tahry
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Claus Bruehl
- Institute for Physiology and Pathophysiology, Heidelberg, Germany
| | - Tanja Heimberger
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Steffi Sandke
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Tanja Weis
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Patrick Most
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Bastian Schmack
- Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Arjang Ruhparwar
- Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias Karck
- Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Norbert Frey
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Kiel, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Hugo A Katus
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
- HCR (Heidelberg Center for Heart Rhythm Disorders), Heidelberg, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany.
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4
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da Rocha AM, Creech J, Thonn E, Mironov S, Herron TJ. Detection of Drug-Induced Torsades de Pointes Arrhythmia Mechanisms Using hiPSC-CM Syncytial Monolayers in a High-Throughput Screening Voltage Sensitive Dye Assay. Toxicol Sci 2020; 173:402-415. [PMID: 31764978 DOI: 10.1093/toxsci/kfz235] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We validated 3 distinct hiPSC-CM cell lines-each of different purity and a voltage sensitive dye (VSD)-based high-throughput proarrhythmia screening assay as a noncore site in the recently completed CiPA Myocyte Phase II Validation Study. Blinded validation was performed using 12 drugs linked to low, intermediate, or high risk for causing Torsades de Pointes (TdP). Commercially sourced hiPSC-CMs were obtained either from Cellular Dynamics International (CDI, Madison, Wisconsin, iCell Cardiomyoyctes2) or Takara Bio (CLS, Cellartis Cardiomyocytes). A third hiPSC-CM cell line (MCH, Michigan) was generated in house. Each cell type had distinct baseline electrophysiological function (spontaneous beat rate, action potential duration, and conduction velocity) and drug responsiveness. Use of VSD and optical mapping enabled the detection of conduction slowing of sodium channel blockers (quinidine, disopyramide, and mexiletine) and drug-induced TdP-like activation patterns (rotors) for some high- and intermediate-risk compounds. Low-risk compounds did not induce rotors in any cell type tested. These results further validate the utility of hiPSC-CMs for predictive proarrhythmia screening and the utility of VSD technology to detect drug-induced APD prolongation, arrhythmias (rotors), and conduction slowing. Importantly, results indicate that different ratios of cardiomyocytes and noncardiomyocytes have important impact on drug response that may be considered during risk assessment of new drugs. Finally, we present the first blinded CiPA hiPSC-CM validation results to simultaneously detect drug-induced conduction slowing, action potential duration prolongation, action potential triangulation, and drug-induced rotors in a proarrhythmia assay.
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Affiliation(s)
- Andre Monteiro da Rocha
- Frankel Cardiovascular Regeneration Core Laboratory, Ann Arbor, MI.,Center for Arrhythmia Research-Department of Internal Medicine, University of Michigan, Ann Arbor, MI.,CARTOX, LLC-Cardiotoxicity Department, New Hudson, MI 48165
| | - Jeffery Creech
- Frankel Cardiovascular Regeneration Core Laboratory, Ann Arbor, MI.,Center for Arrhythmia Research-Department of Internal Medicine, University of Michigan, Ann Arbor, MI.,CARTOX, LLC-Cardiotoxicity Department, New Hudson, MI 48165
| | - Ethan Thonn
- Frankel Cardiovascular Regeneration Core Laboratory, Ann Arbor, MI
| | - Sergey Mironov
- Center for Arrhythmia Research-Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Todd J Herron
- Frankel Cardiovascular Regeneration Core Laboratory, Ann Arbor, MI.,Center for Arrhythmia Research-Department of Internal Medicine, University of Michigan, Ann Arbor, MI.,CARTOX, LLC-Cardiotoxicity Department, New Hudson, MI 48165
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5
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Dou W, Zhao Q, Malhi M, Liu X, Zhang Z, Wang L, Masse S, Nanthakumar K, Hamilton R, Maynes JT, Sun Y. Label-free conduction velocity mapping and gap junction assessment of functional iPSC-Cardiomyocyte monolayers. Biosens Bioelectron 2020; 167:112468. [PMID: 32829174 DOI: 10.1016/j.bios.2020.112468] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023]
Abstract
Cardiac conduction is an important function of the heart. To date, accurate measurement of conduction velocity (CV) in vitro is hindered by the low spatial resolution and poor signal-to-noise ratio of microelectrode arrays (MEAs), or the cytotoxicity and end-point analysis of fluorescence optical imaging. Here, we have developed a new label-free method based on defocused brightfield imaging to quantify CV by analyzing centroid displacements and contraction trajectories of each cardiomyocyte in a monolayer of human stem cell-derived cardiomyocytes (iPSC-CMs). Our data revealed that the time delay between intracellular calcium release and the initiation of cell contraction is highly consistent across cardiomyocytes; however, the duration a cell takes to reach its maximum beating magnitude varies significantly, proving that the time delay in excitation-contraction coupling is largely constant in iPSC-CMs. Standard calcium imaging of the same iPSC-CM populations (~106 cells) was conducted for comparison with our label-free method. The results confirmed that our label-free method was capable of achieving highly accurate CV mapping (17.64 ± 0.89 cm/s vs. 17.95 ± 2.29 cm/s, p-value>0.1). Additionally, our method effectively revealed various shapes in cell beating pattern. We also performed label-free CV mapping on disease-specific iPSC-CM monolayers with plakophilin-2 (PKP2) knockdown, which effectively quantified their low CV values and further validated the arrhythmogenic role of PKP2 mutation in arrhythmogenic right ventricular cardiomyopathy (ARVC) through the disruption of cardiac conduction. The label-free method offers a cytotoxic-free technique for long-term measurement of dynamic beating trajectories, beating propagation and conduction velocities of cardiomyocyte monolayers.
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Affiliation(s)
- Wenkun Dou
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, Canada
| | - Qili Zhao
- Institute of Robotics and Automatic Information System and the Tianjin Key Laboratory of Intelligent Robotics, Nankai University, Tianjin, 300071, China
| | - Manpreet Malhi
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
| | - Xingjian Liu
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, Canada
| | - Zhuoran Zhang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, Canada
| | - Li Wang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, Canada
| | | | | | - Robert Hamilton
- Program in Translational Medicine, Hospital for Sick Children, Toronto, M5G 1X8, Canada
| | - Jason T Maynes
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada; Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, M5G 1X8, Canada.
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, M5S 3G9, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, M5S 3G4, Canada; Department of Computer Science, University of Toronto, Toronto, M5T 3A1, Canada.
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6
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Musa H, Marcou CA, Herron TJ, Makara MA, Tester DJ, O'Connell RP, Rosinski B, Guerrero-Serna G, Milstein ML, Monteiro da Rocha A, Ye D, Crotti L, Nesterenko VV, Castelletti S, Torchio M, Kotta MC, Dagradi F, Antzelevitch C, Mohler PJ, Schwartz PJ, Ackerman MJ, Anumonwo JM. Abnormal myocardial expression of SAP97 is associated with arrhythmogenic risk. Am J Physiol Heart Circ Physiol 2020; 318:H1357-H1370. [PMID: 32196358 DOI: 10.1152/ajpheart.00481.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Synapse-associated protein 97 (SAP97) is a scaffolding protein crucial for the functional expression of several cardiac ion channels and therefore proper cardiac excitability. Alterations in the functional expression of SAP97 can modify the ionic currents underlying the cardiac action potential and consequently confer susceptibility for arrhythmogenesis. In this study, we generated a murine model for inducible, cardiac-targeted Sap97 ablation to investigate arrhythmia susceptibility and the underlying molecular mechanisms. Furthermore, we sought to identify human SAP97 (DLG1) variants that were associated with inherited arrhythmogenic disease. The murine model of cardiac-specific Sap97 ablation demonstrated several ECG abnormalities, pronounced action potential prolongation subject to high incidence of arrhythmogenic afterdepolarizations and notable alterations in the activity of the main cardiac ion channels. However, no DLG1 mutations were found in 40 unrelated cases of genetically elusive long QT syndrome (LQTS). Instead, we provide the first evidence implicating a gain of function in human DLG1 mutation resulting in an increase in Kv4.3 current (Ito) as a novel, potentially pathogenic substrate for Brugada syndrome (BrS). In conclusion, DLG1 joins a growing list of genes encoding ion channel interacting proteins (ChIPs) identified as potential channelopathy-susceptibility genes because of their ability to regulate the trafficking, targeting, and modulation of ion channels that are critical for the generation and propagation of the cardiac electrical impulse. Dysfunction in these critical components of cardiac excitability can potentially result in fatal cardiac disease.NEW & NOTEWORTHY The gene encoding SAP97 (DLG1) joins a growing list of genes encoding ion channel-interacting proteins (ChIPs) identified as potential channelopathy-susceptibility genes because of their ability to regulate the trafficking, targeting, and modulation of ion channels that are critical for the generation and propagation of the cardiac electrical impulse. In this study we provide the first data supporting DLG1-encoded SAP97's candidacy as a minor Brugada syndrome susceptibility gene.
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Affiliation(s)
- Hassan Musa
- Departments of Internal Medicine and of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
| | - Cherisse A Marcou
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases; Division of Pediatric Cardiology, Department of Pediatrics; and Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Todd J Herron
- Departments of Internal Medicine and of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan.,Cardiovascular Regeneration Core Laboratory, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, Michigan
| | - Michael A Makara
- Departments of Internal Medicine and of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - David J Tester
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases; Division of Pediatric Cardiology, Department of Pediatrics; and Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Ryan P O'Connell
- Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
| | - Brad Rosinski
- Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
| | - Guadalupe Guerrero-Serna
- Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
| | - Michelle L Milstein
- Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
| | - André Monteiro da Rocha
- Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan.,Cardiovascular Regeneration Core Laboratory, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, Michigan
| | - Dan Ye
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases; Division of Pediatric Cardiology, Department of Pediatrics; and Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Lia Crotti
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,IRCCS Istituto Auxologico Italiano, San Luca Hospital, Milan, Italy.,IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy
| | | | - Silvia Castelletti
- IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy
| | - Margherita Torchio
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy
| | - Maria-Christina Kotta
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy
| | - Federica Dagradi
- IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy
| | | | - Peter J Mohler
- Departments of Internal Medicine and of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine and Wexner Medical Center, Columbus, Ohio
| | - Peter J Schwartz
- IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy
| | - Michael J Ackerman
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases; Division of Pediatric Cardiology, Department of Pediatrics; and Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Justus M Anumonwo
- Departments of Internal Medicine (Cardiovascular) and of Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
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7
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Zimik S, Pandit R, Majumder R. Anisotropic shortening in the wavelength of electrical waves promotes onset of electrical turbulence in cardiac tissue: An in silico study. PLoS One 2020; 15:e0230214. [PMID: 32168323 PMCID: PMC7069633 DOI: 10.1371/journal.pone.0230214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/24/2020] [Indexed: 12/03/2022] Open
Abstract
Several pathological conditions introduce spatial variations in the electrical properties of cardiac tissue. These variations occur as localized or distributed gradients in ion-channel functionality over extended tissue media. Electrical waves, propagating through such affected tissue, demonstrate distortions, depending on the nature of the ionic gradient in the diseased substrate. If the degree of distortion is large, reentrant activity may develop, in the form of rotating spiral (2d) and scroll (3d) waves of electrical activity. These reentrant waves are associated with the occurrence of lethal cardiac rhythm disorders, known as arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), which are believed to be common precursors of sudden cardiac arrest. By using state-of-the-art mathematical models for generic, and ionically-realistic (human) cardiac tissue, we study the detrimental effects of these ionic gradients on electrical wave propagation. We propose a possible mechanism for the development of instabilities in reentrant wave patterns, in the presence of ionic gradients in cardiac tissue, which may explain how one type of arrhythmia (VT) can degenerate into another (VF). Our proposed mechanism entails anisotropic reduction in the wavelength of the excitation waves because of anisotropic variation in its electrical properties, in particular the action potential duration (APD). We find that the variation in the APD, which we induce by varying ion-channel conductances, imposes a spatial variation in the spiral- or scroll-wave frequency ω. Such gradients in ω induce anisotropic shortening of wavelength of the spiral or scroll arms and eventually leads to instabilitites.
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Affiliation(s)
- Soling Zimik
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
| | - Rahul Pandit
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
| | - Rupamanjari Majumder
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- * E-mail:
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8
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Avula UMR, Abrams J, Katchman A, Zakharov S, Mironov S, Bayne J, Roybal D, Gorti A, Yang L, Iyer V, Waase M, Saluja D, Ciaccio EJ, Garan H, Marks AR, Marx SO, Wan EY. Heterogeneity of the action potential duration is required for sustained atrial fibrillation. JCI Insight 2019; 5:128765. [PMID: 31021331 DOI: 10.1172/jci.insight.128765] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia and accounts for substantial morbidity and mortality. Recently, we created a mouse model with spontaneous and sustained AF caused by a mutation in the NaV1.5 channel (F1759A) that enhances persistent Na+ current, thereby enabling the investigation of molecular mechanisms that cause AF and the identification of novel treatment strategies. The mice have regional heterogeneity of action potential duration of the atria similar to observations in patients with AF. In these mice, we found that the initiation and persistence of the rotational reentrant AF arrhythmias, known as spiral waves or rotors, were dependent upon action potential duration heterogeneity. The centers of the rotors were localized to regions of greatest heterogeneity of the action potential duration. Pharmacologically attenuating the action potential duration heterogeneity reduced both spontaneous and pacing-induced AF. Computer-based simulations also demonstrated that the action potential duration heterogeneity is sufficient to generate rotors that manifest as AF. Taken together, these findings suggest that action potential duration heterogeneity in mice and humans is one mechanism by which AF is initiated and that reducing action potential duration heterogeneity can lessen the burden of AF.
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Affiliation(s)
- Uma Mahesh R Avula
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Jeffrey Abrams
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Alexander Katchman
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Sergey Zakharov
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Sergey Mironov
- Center for Arrhythmia Research, Division of Cardiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Joseph Bayne
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Daniel Roybal
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Anirudh Gorti
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Lin Yang
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Vivek Iyer
- Marin General Hospital, Greenbrae, California, USA
| | - Marc Waase
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Deepak Saluja
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Edward J Ciaccio
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Hasan Garan
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Andrew R Marks
- The Wu Center for Molecular Cardiology, Columbia University, New York, New York, USA.,Department of Physiology and Cellular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Elaine Y Wan
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
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9
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Biton Y, Rabinovitch A, Braunstein D, Aviram I, Campbell K, Mironov S, Herron T, Jalife J, Berenfeld O. Causality analysis of leading singular value decomposition modes identifies rotor as the dominant driving normal mode in fibrillation. CHAOS (WOODBURY, N.Y.) 2018; 28:013128. [PMID: 29390625 PMCID: PMC5786449 DOI: 10.1063/1.5021261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 12/28/2017] [Indexed: 06/07/2023]
Abstract
Cardiac fibrillation is a major clinical and societal burden. Rotors may drive fibrillation in many cases, but their role and patterns are often masked by complex propagation. We used Singular Value Decomposition (SVD), which ranks patterns of activation hierarchically, together with Wiener-Granger causality analysis (WGCA), which analyses direction of information among observations, to investigate the role of rotors in cardiac fibrillation. We hypothesized that combining SVD analysis with WGCA should reveal whether rotor activity is the dominant driving force of fibrillation even in cases of high complexity. Optical mapping experiments were conducted in neonatal rat cardiomyocyte monolayers (diameter, 35 mm), which were genetically modified to overexpress the delayed rectifier K+ channel IKr only in one half of the monolayer. Such monolayers have been shown previously to sustain fast rotors confined to the IKr overexpressing half and driving fibrillatory-like activity in the other half. SVD analysis of the optical mapping movies revealed a hierarchical pattern in which the primary modes corresponded to rotor activity in the IKr overexpressing region and the secondary modes corresponded to fibrillatory activity elsewhere. We then applied WGCA to evaluate the directionality of influence between modes in the entire monolayer using clear and noisy movies of activity. We demonstrated that the rotor modes influence the secondary fibrillatory modes, but influence was detected also in the opposite direction. To more specifically delineate the role of the rotor in fibrillation, we decomposed separately the respective SVD modes of the rotor and fibrillatory domains. In this case, WGCA yielded more information from the rotor to the fibrillatory domains than in the opposite direction. In conclusion, SVD analysis reveals that rotors can be the dominant modes of an experimental model of fibrillation. Wiener-Granger causality on modes of the rotor domains confirms their preferential driving influence on fibrillatory modes.
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Affiliation(s)
- Yaacov Biton
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Avinoam Rabinovitch
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Doron Braunstein
- Physics Department, Sami Shamoon College of Engineering, Beer-Sheva 84100, Israel
| | - Ira Aviram
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Katherine Campbell
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Sergey Mironov
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Todd Herron
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - José Jalife
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Omer Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan 48109, USA
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10
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da Rocha AM, Campbell K, Mironov S, Jiang J, Mundada L, Guerrero-Serna G, Jalife J, Herron TJ. hiPSC-CM Monolayer Maturation State Determines Drug Responsiveness in High Throughput Pro-Arrhythmia Screen. Sci Rep 2017; 7:13834. [PMID: 29061979 PMCID: PMC5653750 DOI: 10.1038/s41598-017-13590-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/26/2023] Open
Abstract
Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) offer a novel in vitro platform for pre-clinical cardiotoxicity and pro-arrhythmia screening of drugs in development. To date hiPSC-CMs used for cardiotoxicity testing display an immature, fetal-like cardiomyocyte structural and electrophysiological phenotype which has called into question the applicability of hiPSC-CM findings to the adult heart. The aim of the current work was to determine the effect of cardiomyocyte maturation state on hiPSC-CM drug responsiveness. To this end, here we developed a high content pro-arrhythmia screening platform consisting of either fetal-like or mature hiPSC-CM monolayers. Compounds tested in the screen were selected based on the pro-arrhythmia risk classification (Low risk, Intermediate risk, or High risk) established recently by the FDA and major stakeholders in the Drug Discovery field for the validation of the Comprehensive In vitro Pro-Arrhythmia Assay (CiPA). Here we show that maturation state of hiPSC-CMs determines the absolute pro-arrhythmia risk score calculated for these compounds. Thus, the maturation state of hiPSC-CMs should be considered prior to pro-arrhythmia and cardiotoxicity screening in drug discovery programs.
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Affiliation(s)
- André Monteiro da Rocha
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA.,Frankel Cardiovascular Center, Cardiovascular Regeneration Core Laboratory, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Katherine Campbell
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA
| | - Sergey Mironov
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA
| | - Jiang Jiang
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA
| | - Lakshmi Mundada
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA
| | - Guadalupe Guerrero-Serna
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA
| | - José Jalife
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA.,Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029, Madrid, Spain.,CIBER of Cardiovascular Diseases (CIBERCV), ISCIII, Madrid, Spain
| | - Todd J Herron
- University of Michigan, Internal Medicine-Cardiology, Center for Arrhythmia Research, Ann Arbor, MI, 48109, USA. .,Frankel Cardiovascular Center, Cardiovascular Regeneration Core Laboratory, University of Michigan, Ann Arbor, MI, 48109, USA.
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11
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Berenfeld O. The Major Role of IK1 in Mechanisms of Rotor Drift in the Atria: A Computational Study. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2016; 10:71-79. [PMID: 28096699 PMCID: PMC5175588 DOI: 10.4137/cmc.s39773] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/17/2016] [Accepted: 11/20/2016] [Indexed: 12/19/2022]
Abstract
Maintenance of paroxysmal atrial fibrillation (AF) by fast rotors in the left atrium (LA) or at the pulmonary veins (PVs) is not fully understood. This review describes the role of the heterogeneous distribution of transmembrane currents in the PVs and LA junction (PV-LAJ) in the localization of rotors in the PVs. Experimentally observed heterogeneities in IK1, IKs, IKr, Ito, and ICaL in the PV-LAJ were incorporated into models of human atrial kinetics to simulate various conditions and investigate rotor drifting mechanisms. Spatial gradients in the currents resulted in shorter action potential duration, less negative minimum diastolic potential, slower upstroke and conduction velocity for rotors in the PV region than in the LA. Rotors under such conditions drifted toward the PV and stabilized at the less excitable region. Our simulations suggest that IK1 heterogeneity is dominant in determining the drift direction through its impact on the excitability gradient. These results provide a novel framework for understanding the complex dynamics of rotors in AF.
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Affiliation(s)
- Omer Berenfeld
- Center for Arrhythmia Research, Internal Medicine and Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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12
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Czick ME, Shapter CL, Silverman DI. Atrial Fibrillation: The Science behind Its Defiance. Aging Dis 2016; 7:635-656. [PMID: 27699086 PMCID: PMC5036958 DOI: 10.14336/ad.2016.0211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 02/11/2016] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent arrhythmia in the world, due both to its tenacious treatment resistance, and to the tremendous number of risk factors that set the stage for the atria to fibrillate. Cardiopulmonary, behavioral, and psychological risk factors generate electrical and structural alterations of the atria that promote reentry and wavebreak. These culminate in fibrillation once atrial ectopic beats set the arrhythmia process in motion. There is growing evidence that chronic stress can physically alter the emotion centers of the limbic system, changing their input to the hypothalamic-limbic-autonomic network that regulates autonomic outflow. This leads to imbalance of the parasympathetic and sympathetic nervous systems, most often in favor of sympathetic overactivation. Autonomic imbalance acts as a driving force behind the atrial ectopy and reentry that promote AF. Careful study of AF pathophysiology can illuminate the means that enable AF to elude both pharmacological control and surgical cure, by revealing ways in which antiarrhythmic drugs and surgical and ablation procedures may paradoxically promote fibrillation. Understanding AF pathophysiology can also help clarify the mechanisms by which emerging modalities aiming to correct autonomic imbalance, such as renal sympathetic denervation, may offer potential to better control this arrhythmia. Finally, growing evidence supports lifestyle modification approaches as adjuncts to improve AF control.
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Affiliation(s)
| | | | - David I. Silverman
- Echocardiography Laboratory, Hartford Hospital, Hartford, CT 06106, USA.
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13
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Herron TJ, Rocha AMD, Campbell KF, Ponce-Balbuena D, Willis BC, Guerrero-Serna G, Liu Q, Klos M, Musa H, Zarzoso M, Bizy A, Furness J, Anumonwo J, Mironov S, Jalife J. Extracellular Matrix-Mediated Maturation of Human Pluripotent Stem Cell-Derived Cardiac Monolayer Structure and Electrophysiological Function. Circ Arrhythm Electrophysiol 2016; 9:e003638. [PMID: 27069088 DOI: 10.1161/circep.113.003638] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 03/16/2016] [Indexed: 01/12/2023]
Abstract
BACKGROUND Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) monolayers generated to date display an immature embryonic-like functional and structural phenotype that limits their utility for research and cardiac regeneration. In particular, the electrophysiological function of hPSC-CM monolayers and bioengineered constructs used to date are characterized by slow electric impulse propagation velocity and immature action potential profiles. METHODS AND RESULTS Here, we have identified an optimal extracellular matrix for significant electrophysiological and structural maturation of hPSC-CM monolayers. hPSC-CM plated in the optimal extracellular matrix combination have impulse propagation velocities ≈2× faster than previously reported (43.6±7.0 cm/s; n=9) and have mature cardiomyocyte action potential profiles, including hyperpolarized diastolic potential and rapid action potential upstroke velocity (146.5±17.7 V/s; n=5 monolayers). In addition, the optimal extracellular matrix promoted hypertrophic growth of cardiomyocytes and the expression of key mature sarcolemmal (SCN5A, Kir2.1, and connexin43) and myofilament markers (cardiac troponin I). The maturation process reported here relies on activation of integrin signaling pathways: neutralization of β1 integrin receptors via blocking antibodies and pharmacological blockade of focal adhesion kinase activation prevented structural maturation. CONCLUSIONS Maturation of human stem cell-derived cardiomyocyte monolayers is achieved in a 1-week period by plating cardiomyocytes on PDMS (polydimethylsiloxane) coverslips rather than on conventional 2-dimensional cell culture formats, such as glass coverslips or plastic dishes. Activation of integrin signaling and focal adhesion kinase is essential for significant maturation of human cardiac monolayers.
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Affiliation(s)
- Todd J Herron
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.).
| | - Andre Monteiro Da Rocha
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Katherine F Campbell
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Daniela Ponce-Balbuena
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - B Cicero Willis
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Guadalupe Guerrero-Serna
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Qinghua Liu
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Matt Klos
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Hassan Musa
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Manuel Zarzoso
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Alexandra Bizy
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Jamie Furness
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Justus Anumonwo
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - Sergey Mironov
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
| | - José Jalife
- From the Center for Arrhythmia Research, Department of Internal Medicine, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI (T.J.H., A.M.D.R., K.C., D.P.-B., B.C.W., G.G.-S., Q.L., J.F., J.A., S.M., J.J.); Department of Medicine, University of California San Diego, La Jolla, CA (M.K.); Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH (H.M.); Shanxi Medical University, Zhejiang, China (Q.L.); and University of Valencia, Valencia, Spain (M.Z., A.B.)
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14
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Tsai FC, Lin YC, Chang SH, Chang GJ, Hsu YJ, Lin YM, Lee YS, Wang CL, Yeh YH. Differential left-to-right atria gene expression ratio in human sinus rhythm and atrial fibrillation: Implications for arrhythmogenesis and thrombogenesis. Int J Cardiol 2016; 222:104-112. [PMID: 27494721 DOI: 10.1016/j.ijcard.2016.07.103] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 12/26/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) causes atrial remodeling, and the left atrium (LA) is the favored substrate for maintaining AF. It remains unclear if AF remodels both atria differently and contributes to LA arrhythmogenesis and thrombogenesis. Therefore, we wished to characterize the transcript profiles in the LA and right atrium (RA) in sinus rhythm (SR) and AF respectively. METHODS Paired LA and RA appendages acquired from patients receiving cardiac surgery were used for ion-channel- and whole-exome-based transcriptome analysis. The ultrastructure was evaluated by immunohistochemistry. RESULTS Twenty-two and twenty ion-channels and transporters were differentially expressed between the LA and RA in AF and SR, respectively. Among these, 15 genes were differentially expressed in parallel between AF and SR. AF was associated with increased LA/RA expression ratio in 9 ion channel-related genes, including genes related to calcium handling. In microarray, AF was associated with a differential LA/RA gene expression ratio in 309 genes, and was involved in atherosclerosis-related signaling. AF was associated with the upregulation of thrombogenesis-related genes in the LA appendage, including P2Y12, CD 36 and ApoE. Immunohistochemistry showed higher expressions of collagen-1, oxidative stress and TGF-β1 in the RA compared to the LA. CONCLUSIONS AF was associated with differential LA-to-RA gene expression related to specific ion channels and pathways as well as upregulation of thrombogenesis-related genes in the LA appendage. Targeting the molecular mechanisms underlying the LA-to-RA difference and AF-related remodeling in the LA appendage may help provide new therapeutic options in treating AF and preventing thromboembolism in AF.
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Affiliation(s)
- Feng-Chun Tsai
- Division of Cardiac Surgery, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Yen-Chen Lin
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Shang-Hung Chang
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Gwo-Jyh Chang
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University College of Medicine, Chang-Gung University, Taiwan
| | - Yu-Juei Hsu
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yuan-Min Lin
- School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Yun-Shien Lee
- Department of Biotechnology, Ming-Chuan University, Taoyuan, Taiwan
| | - Chun-Li Wang
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Yung-Hsin Yeh
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan.
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15
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Optical Imaging of Cardiac Action Potential. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:299-311. [PMID: 26238058 DOI: 10.1007/978-3-319-17641-3_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This chapter reviews the major milestones and scientific achievements facilitated by optical imaging of the action potential in the heart over more than four decades since its introduction. We discuss the limitations of this technique, which sometimes are not fully recognized; the unresolved issues, such as motion artifacts, and the newest developments and future directions.
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16
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Calvo CJ, Deo M, Zlochiver S, Millet J, Berenfeld O. Attraction of rotors to the pulmonary veins in paroxysmal atrial fibrillation: a modeling study. Biophys J 2014; 106:1811-21. [PMID: 24739180 DOI: 10.1016/j.bpj.2014.02.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/10/2014] [Accepted: 02/25/2014] [Indexed: 12/19/2022] Open
Abstract
Maintenance of paroxysmal atrial fibrillation (AF) by fast rotors in the left atrium (LA) or at the pulmonary veins (PVs) is not fully understood. To gain insight into this dynamic and complex process, we studied the role of the heterogeneous distribution of transmembrane currents in the PVs and LA junction (PV-LAJ) in the localization of rotors in the PVs. We also investigated whether simple pacing protocols could be used to predict rotor drift in the PV-LAJ. Experimentally observed heterogeneities in IK1, IKs, IKr, Ito, and ICaL in the PV-LAJ were incorporated into two- and pseudo three-dimensional models of Courtemanche-Ramirez-Nattel-Kneller human atrial kinetics to simulate various conditions and investigate rotor drifting mechanisms. Spatial gradients in the currents resulted in shorter action potential duration, minimum diastolic potential that was less negative, and slower upstroke and conduction velocity for rotors in the PV region than in the LA. Rotors under such conditions drifted toward the PV and stabilized at the shortest action potential duration and less-excitable region, consistent with drift direction under intercellular coupling heterogeneities and regardless of the geometrical constraint in the PVs. Simulations with various IK1 gradient conditions and current-voltage relationships substantiated its major role in the rotor drift. In our 1:1 pacing protocol, we found that among various action potential properties, only the minimum diastolic potential gradient was a rate-independent predictor of rotor drift direction. Consistent with experimental and clinical AF studies, simulations in an electrophysiologically heterogeneous model of the PV-LAJ showed rotor attraction toward the PV. Our simulations suggest that IK1 heterogeneity is dominant compared to other currents in determining the drift direction through its impact on the excitability gradient. These results provide a believed novel framework for understanding the complex dynamics of rotors in AF.
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Affiliation(s)
- Conrado J Calvo
- Center for Arrhythmia Research, Department of Internal Medicine, and Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; BioITACA Grupo de Bioingeniería, Instituto de Aplicaciones Avanzadas, Valencia, Spain; Departamento Ingeniería Electrónica, Universitat Politècnica de Valencia, Valencia, Spain
| | - Makarand Deo
- Center for Arrhythmia Research, Department of Internal Medicine, and Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Engineering, Norfolk State University, Norfolk, Virginia
| | - Sharon Zlochiver
- Center for Arrhythmia Research, Department of Internal Medicine, and Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, Tel Aviv University, Ramat Aviv, Israel
| | - José Millet
- BioITACA Grupo de Bioingeniería, Instituto de Aplicaciones Avanzadas, Valencia, Spain; Departamento Ingeniería Electrónica, Universitat Politècnica de Valencia, Valencia, Spain
| | - Omer Berenfeld
- Center for Arrhythmia Research, Department of Internal Medicine, and Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.
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17
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Majumder R, Pandit R, Panfilov AV. Turbulent electrical activity at sharp-edged inexcitable obstacles in a model for human cardiac tissue. Am J Physiol Heart Circ Physiol 2014; 307:H1024-35. [DOI: 10.1152/ajpheart.00593.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Wave propagation around various geometric expansions, structures, and obstacles in cardiac tissue may result in the formation of unidirectional block of wave propagation and the onset of reentrant arrhythmias in the heart. Therefore, we investigated the conditions under which reentrant spiral waves can be generated by high-frequency stimulation at sharp-edged obstacles in the ten Tusscher-Noble-Noble-Panfilov (TNNP) ionic model for human cardiac tissue. We show that, in a large range of parameters that account for the conductance of major inward and outward ionic currents of the model [fast inward Na+ current ( INa), L—type slow inward Ca2+ current ( ICaL), slow delayed-rectifier current ( IKs), rapid delayed-rectifier current ( IKr), inward rectifier K+ current ( IK1)], the critical period necessary for spiral formation is close to the period of a spiral wave rotating in the same tissue. We also show that there is a minimal size of the obstacle for which formation of spirals is possible; this size is ∼2.5 cm and decreases with a decrease in the excitability of cardiac tissue. We show that other factors, such as the obstacle thickness and direction of wave propagation in relation to the obstacle, are of secondary importance and affect the conditions for spiral wave initiation only slightly. We also perform studies for obstacle shapes derived from experimental measurements of infarction scars and show that the formation of spiral waves there is facilitated by tissue remodeling around it. Overall, we demonstrate that the formation of reentrant sources around inexcitable obstacles is a potential mechanism for the onset of cardiac arrhythmias in the presence of a fast heart rate.
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Affiliation(s)
- Rupamanjari Majumder
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rahul Pandit
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - A. V. Panfilov
- Department of Physics and Astronomy, Gent University, Ghent, Belgium; and
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia
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18
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Waks JW, Josephson ME. Mechanisms of Atrial Fibrillation - Reentry, Rotors and Reality. Arrhythm Electrophysiol Rev 2014; 3:90-100. [PMID: 26835073 DOI: 10.15420/aer.2014.3.2.90] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 08/08/2014] [Indexed: 01/02/2023] Open
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, yet our understanding of the mechanisms that initiate and sustain this arrhythmia remains quite poor. Over the last 50 years, various mechanisms of AF have been proposed, yet none has been consistently observed in both experimental studies and in humans. Recently, there has been increasing interest in understanding how spiral waves or rotors - which are specific, organised forms of functional reentry - sustain human AF and how they might be therapeutic targets for catheter-based ablation. The following review describes the historical understanding of reentry and AF mechanisms from earlier in the 20th century, advances in our understanding of mechanisms that are able to sustain AF with a focus on rotors and complex fractionated atrial electrograms (CFAEs), and how the study of AF mechanisms has resulted in new strategies for treating AF with novel forms of catheter ablation.
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Affiliation(s)
- Jonathan W Waks
- Clinical Fellow in Cardiac Electrophysiology, Harvard Medical School, Harvard-Thorndike Electrophysiology Institute and Arrhythmia Service, Beth Israel Deaconess Medical Center, Boston, US
| | - Mark E Josephson
- Herman C. Dana Professor of Medicine, Harvard Medical School, Chief of the Cardiovascular Division, Beth Israel Deaconess Medical Center and Director, Harvard-Thorndike Electrophysiology Institute and Arrhythmia Service, Beth Israel Deaconess Medical Center, Boston, US
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19
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Rodrigo M, Guillem MS, Climent AM, Pedrón-Torrecilla J, Liberos A, Millet J, Fernández-Avilés F, Atienza F, Berenfeld O. Body surface localization of left and right atrial high-frequency rotors in atrial fibrillation patients: a clinical-computational study. Heart Rhythm 2014; 11:1584-91. [PMID: 24846374 DOI: 10.1016/j.hrthm.2014.05.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Ablation is an effective therapy in patients with atrial fibrillation (AF) in which an electrical driver can be identified. OBJECTIVE The aim of this study was to present and discuss a novel and strictly noninvasive approach to map and identify atrial regions responsible for AF perpetuation. METHODS Surface potential recordings of 14 patients with AF were recorded using a 67-lead recording system. Singularity points (SPs) were identified in surface phase maps after band-pass filtering at the highest dominant frequency (HDF). Mathematical models of combined atria and torso were constructed and used to investigate the ability of surface phase maps to estimate rotor activity in the atrial wall. RESULTS The simulations show that surface SPs originate at atrial SPs, but not all atrial SPs are reflected at the surface. Stable SPs were found in AF signals during 8.3% ± 5.7% vs. 73.1% ± 16.8% of the time in unfiltered vs. HDF-filtered patient data, respectively (P < .01). The average duration of each rotational pattern was also lower in unfiltered than in HDF-filtered AF signals (160 ± 43 ms vs. 342 ± 138 ms; P < .01), resulting in 2.8 ± 0.7 rotations per rotor. Band-pass filtering reduced the apparent meandering of surface HDF rotors by reducing the effect of the atrial electrical activity occurring at different frequencies. Torso surface SPs representing HDF rotors during AF were reflected at specific areas corresponding to the fastest atrial location. CONCLUSION Phase analysis of surface potential signals after HDF filtering during AF shows reentrant drivers localized to either the left atrium or the right atrium, helping in localizing ablation targets.
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Affiliation(s)
- Miguel Rodrigo
- Bio-ITACA, Universitat Politécnica de Valencia, Valencia, Spain
| | - María S Guillem
- Bio-ITACA, Universitat Politécnica de Valencia, Valencia, Spain.
| | - Andreu M Climent
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | | | | | - José Millet
- Bio-ITACA, Universitat Politécnica de Valencia, Valencia, Spain
| | - Francisco Fernández-Avilés
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Felipe Atienza
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
| | - Omer Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
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20
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Defauw A, Dawyndt P, Panfilov AV. Initiation and dynamics of a spiral wave around an ionic heterogeneity in a model for human cardiac tissue. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:062703. [PMID: 24483482 DOI: 10.1103/physreve.88.062703] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/18/2013] [Indexed: 06/03/2023]
Abstract
In relation to cardiac arrhythmias, heterogeneity of cardiac tissue is one of the most important factors underlying the onset of spiral waves and determining their type. In this paper, we numerically model heterogeneity of realistic size and value and study formation and dynamics of spiral waves around such heterogeneity. We find that the only sustained pattern obtained is a single spiral wave anchored around the heterogeneity. Dynamics of an anchored spiral wave depend on the extent of heterogeneity, and for certain heterogeneity size, we find abrupt regional increase in the period of excitation occurring as a bifurcation. We study factors determining spatial distribution of excitation periods of anchored spiral waves and discuss consequences of such dynamics for cardiac arrhythmias and possibilities for experimental testings of our predictions.
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Affiliation(s)
- Arne Defauw
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Peter Dawyndt
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, Belgium
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21
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Abstract
The objective of this article is to present a broad review of the role of cardiac electric rotors and their accompanying spiral waves in the mechanism of cardiac fibrillation. At the outset, we present a brief historical overview regarding reentry and then discuss the basic concepts and terminologies pertaining to rotors and their initiation. Thereafter, the intrinsic properties of rotors and spiral waves, including phase singularities, wavefront curvature, and dominant frequency maps, are discussed. The implications of rotor dynamics for the spatiotemporal organization of fibrillation, independent of the species being studied, are described next. The knowledge gained regarding the role of cardiac structure in the initiation or maintenance of rotors and the ionic bases of spiral waves in the past 2 decades, as well as the significance for drug therapy, is reviewed subsequently. We conclude by examining recent evidence suggesting that rotors are critical in sustaining both atrial and ventricular fibrillation in the human heart and its implications for treatment with radiofrequency ablation.
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Affiliation(s)
- Sandeep V Pandit
- Center for Arrhythmia Research, University of Michigan, NCRC, 2800 Plymouth Rd, Ann Arbor, MI 48109, USA
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22
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Dor-Haim H, Berenfeld O, Horowitz M, Lotan C, Swissa M. Reduced Ventricular Arrhythmogeneity and Increased Electrical Complexity in Normal Exercised Rats. PLoS One 2013; 8:e66658. [PMID: 23825553 PMCID: PMC3688953 DOI: 10.1371/journal.pone.0066658] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 05/09/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The mechanisms whereby aerobic training reduces the occurrence of sudden cardiac death in humans are not clear. We test the hypothesis that exercise-induced increased resistance to ventricular tachycardia and fibrillation (VT/VF) involve an intrinsic remodeling in healthy hearts. METHODS AND RESULTS Thirty rats were divided into a sedentary (CTRL, n = 16) and two exercise groups: short- (4 weeks, ST, n = 7) and long-term (8 weeks, LT, n = 7) trained groups. Following the exercise program hearts were isolated and studied in a Langendorff perfusion system. An S1-S2 pacing protocol was applied at the right ventricle to determine inducibility of VT/VF. Fast Fourier transforms were applied on ECG time-series. In-vivo measurements showed training-induced increase in aerobic capacity, heart-to-body weight ratio and a 50% low-to-high frequency ratio reduction in the heart rate variability (p<0.05). In isolated hearts the probability for VF decreased from 26.1±14.4 in CTRL to 13.9±14.1 and 6.7±8.5% in the ST and LT, respectively (p<0.05). Duration of VF also decreased from 19.0±5.7 in CTRL to 8.8±7.1 and 6.0±5.8 sec in ST and LT respectively (p<0.05). Moreover, the pacing current required for VF induction increased following exercise (2.9±1.7 vs. 5.4±2.1 and 8.5±0.9 mA, respectively; p<0.05). Frequency analysis of ECG revealed an exercise-induced VF transition from a narrow single peak spectrum at 17 Hz in CTRL to a broader range of peaks ranging between 8.8 and 22.5 Hz in the LT group (p<0.05). CONCLUSION Exercise in rats leads to reduced VF propensity associated with an intrinsic cardiac remodeling related to a broader spectral range and faster frequency components in the ECG.
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Affiliation(s)
- Horesh Dor-Haim
- Heart Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Omer Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Michal Horowitz
- Department of Physiology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Chaim Lotan
- Heart Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Moshe Swissa
- Cardiac Research Center, Kaplan Medical Center, Rehovot, Israel
- * E-mail:
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