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Mo W, Donahue JK. Gene therapy for atrial fibrillation. J Mol Cell Cardiol 2024; 196:84-93. [PMID: 39270930 DOI: 10.1016/j.yjmcc.2024.09.004] [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: 11/09/2023] [Revised: 08/19/2024] [Accepted: 09/03/2024] [Indexed: 09/15/2024]
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia in adults. Current limitations of pharmacological and ablative therapies motivate the development of novel therapies as next generation treatments for AF. The arrhythmia mechanisms creating and sustaining AF are key elements in the development of this novel treatment. Gene therapy provides a useful platform that allows us to regulate the mechanisms of interest using a suitable transgene(s), vector, and delivery method. Effective gene therapy strategies in the literature have targeted maladaptive electrical or structural remodeling that increase vulnerability to AF. In this review, we will summarize key elements of gene therapy for AF, including molecular targets, gene transfer vectors, atrial gene delivery and preclinical efficacy and toxicity testing. Recent advances and challenges in the field will be also discussed.
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Affiliation(s)
- Weilan Mo
- From the Division of Cardiology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - J Kevin Donahue
- From the Division of Cardiology, University of Massachusetts Medical School, Worcester, MA, United States of America.
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2
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Medvedev RY, Afolabi SO, Turner DGP, Glukhov AV. Mechanisms of stretch-induced electro-anatomical remodeling and atrial arrhythmogenesis. J Mol Cell Cardiol 2024; 193:11-24. [PMID: 38797242 PMCID: PMC11260238 DOI: 10.1016/j.yjmcc.2024.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 05/29/2024]
Abstract
Atrial fibrillation (AF) is the most common cardiac rhythm disorder, often occurring in the setting of atrial distension and elevated myocardialstretch. While various mechano-electrochemical signal transduction pathways have been linked to AF development and progression, the underlying molecular mechanisms remain poorly understood, hampering AF therapies. In this review, we describe different aspects of stretch-induced electro-anatomical remodeling as seen in animal models and in patients with AF. Specifically, we focus on cellular and molecular mechanisms that are responsible for mechano-electrochemical signal transduction and the development of ectopic beats triggering AF from pulmonary veins, the most common source of paroxysmal AF. Furthermore, we describe structural changes caused by stretch occurring before and shortly after the onset of AF as well as during AF progression, contributing to longstanding forms of AF. We also propose mechanical stretch as a new dimension to the concept "AF begets AF", in addition to underlying diseases. Finally, we discuss the mechanisms of these electro-anatomical alterations in a search for potential therapeutic strategies and the development of novel antiarrhythmic drugs targeted at the components of mechano-electrochemical signal transduction not only in cardiac myocytes, but also in cardiac non-myocyte cells.
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Affiliation(s)
- Roman Y Medvedev
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Saheed O Afolabi
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA; Department of Pharmacology and Therapeutics, University of Ilorin, Ilorin, Nigeria
| | - Daniel G P Turner
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Alexey V Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA.
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3
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Jæger KH, Tveito A. A possible path to persistent re-entry waves at the outlet of the left pulmonary vein. NPJ Syst Biol Appl 2024; 10:79. [PMID: 39043674 PMCID: PMC11266599 DOI: 10.1038/s41540-024-00406-9] [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: 03/18/2024] [Accepted: 07/12/2024] [Indexed: 07/25/2024] Open
Abstract
Atrial fibrillation (AF) is the most common form of cardiac arrhythmia, often evolving from paroxysmal episodes to persistent stages over an extended timeframe. While various factors contribute to this progression, the precise biophysical mechanisms driving it remain unclear. Here we explore how rapid firing of cardiomyocytes at the outlet of the pulmonary vein of the left atria can create a substrate for a persistent re-entry wave. This is grounded in a recently formulated mathematical model of the regulation of calcium ion channel density by intracellular calcium concentration. According to the model, the number of calcium channels is controlled by the intracellular calcium concentration. In particular, if the concentration increases above a certain target level, the calcium current is weakened to restore the target level of calcium. During rapid pacing, the intracellular calcium concentration of the cardiomyocytes increases leading to a substantial reduction of the calcium current across the membrane of the myocytes, which again reduces the action potential duration. In a spatially resolved cell-based model of the outlet of the pulmonary vein of the left atria, we show that the reduced action potential duration can lead to re-entry. Initiated by rapid pacing, often stemming from paroxysmal AF episodes lasting several days, the reduction in calcium current is a critical factor. Our findings illustrate how such episodes can foster a conducive environment for persistent AF through electrical remodeling, characterized by diminished calcium currents. This underscores the importance of promptly addressing early AF episodes to prevent their progression to chronic stages.
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Affiliation(s)
| | - Aslak Tveito
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
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4
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Seibertz F, Rubio T, Springer R, Popp F, Ritter M, Liutkute A, Bartelt L, Stelzer L, Haghighi F, Pietras J, Windel H, Pedrosa NDI, Rapedius M, Doering Y, Solano R, Hindmarsh R, Shi R, Tiburcy M, Bruegmann T, Kutschka I, Streckfuss-Bömeke K, Kensah G, Cyganek L, Zimmermann WH, Voigt N. Atrial fibrillation-associated electrical remodelling in human induced pluripotent stem cell-derived atrial cardiomyocytes: a novel pathway for antiarrhythmic therapy development. Cardiovasc Res 2023; 119:2623-2637. [PMID: 37677054 PMCID: PMC10730244 DOI: 10.1093/cvr/cvad143] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 07/18/2023] [Accepted: 08/03/2023] [Indexed: 09/09/2023] Open
Abstract
AIMS Atrial fibrillation (AF) is associated with tachycardia-induced cellular electrophysiology alterations which promote AF chronification and treatment resistance. Development of novel antiarrhythmic therapies is hampered by the absence of scalable experimental human models that reflect AF-associated electrical remodelling. Therefore, we aimed to assess if AF-associated remodelling of cellular electrophysiology can be simulated in human atrial-like cardiomyocytes derived from induced pluripotent stem cells in the presence of retinoic acid (iPSC-aCM), and atrial-engineered human myocardium (aEHM) under short term (24 h) and chronic (7 days) tachypacing (TP). METHODS AND RESULTS First, 24-h electrical pacing at 3 Hz was used to investigate whether AF-associated remodelling in iPSC-aCM and aEHM would ensue. Compared to controls (24 h, 1 Hz pacing) TP-stimulated iPSC-aCM presented classical hallmarks of AF-associated remodelling: (i) decreased L-type Ca2+ current (ICa,L) and (ii) impaired activation of acetylcholine-activated inward-rectifier K+ current (IK,ACh). This resulted in action potential shortening and an absent response to the M-receptor agonist carbachol in both iPSC-aCM and aEHM subjected to TP. Accordingly, mRNA expression of the channel-subunit Kir3.4 was reduced. Selective IK,ACh blockade with tertiapin reduced basal inward-rectifier K+ current only in iPSC-aCM subjected to TP, thereby unmasking an agonist-independent constitutively active IK,ACh. To allow for long-term TP, we developed iPSC-aCM and aEHM expressing the light-gated ion-channel f-Chrimson. The same hallmarks of AF-associated remodelling were observed after optical-TP. In addition, continuous TP (7 days) led to (i) increased amplitude of inward-rectifier K+ current (IK1), (ii) hyperpolarization of the resting membrane potential, (iii) increased action potential-amplitude and upstroke velocity as well as (iv) reversibly impaired contractile function in aEHM. CONCLUSIONS Classical hallmarks of AF-associated remodelling were mimicked through TP of iPSC-aCM and aEHM. The use of the ultrafast f-Chrimson depolarizing ion channel allowed us to model the time-dependence of AF-associated remodelling in vitro for the first time. The observation of electrical remodelling with associated reversible contractile dysfunction offers a novel platform for human-centric discovery of antiarrhythmic therapies.
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Affiliation(s)
- Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
| | - Tony Rubio
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Robin Springer
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Fiona Popp
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Melanie Ritter
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Aiste Liutkute
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Lena Bartelt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Lea Stelzer
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Fereshteh Haghighi
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Department of Cardiothoracic and Vascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Jan Pietras
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Department of Cardiothoracic and Vascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Hendrik Windel
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Department of Cardiothoracic and Vascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Núria Díaz i Pedrosa
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | | | - Yannic Doering
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Richard Solano
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Department of Cardiothoracic and Vascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Robin Hindmarsh
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University Göttingen, Germany
| | - Runzhu Shi
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Institute for Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Malte Tiburcy
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Tobias Bruegmann
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
- Institute for Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Ingo Kutschka
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Department of Cardiothoracic and Vascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Katrin Streckfuss-Bömeke
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University Göttingen, Germany
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - George Kensah
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Department of Cardiothoracic and Vascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Lukas Cyganek
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University Göttingen, Germany
| | - Wolfram H Zimmermann
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Göttingen, Germany
- Campus-Institute Data Science (CIDAS), University of Göttingen, Göttingen, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
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Ritzer A, Roeschl T, Nay S, Rudakova E, Volk T. Rapid Pacing Decreases L-type Ca 2+ Current and Alters Cacna1c Isogene Expression in Primary Cultured Rat Left Ventricular Myocytes. J Membr Biol 2023; 256:257-269. [PMID: 36995425 DOI: 10.1007/s00232-023-00284-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 03/14/2023] [Indexed: 03/31/2023]
Abstract
The L-type calcium current (ICaL) is the first step in cardiac excitation-contraction-coupling and plays an important role in regulating contractility, but also in electrical and mechanical remodeling. Primary culture of cardiomyocytes, a widely used tool in cardiac ion channel research, is associated with substantial morphological, functional and electrical changes some of which may be prevented by electrical pacing. We therefore investigated ICaL directly after cell isolation and after 24 h of primary culture with and without regular pacing at 1 and 3 Hz in rat left ventricular myocytes. Moreover, we analyzed total mRNA expression of the pore forming subunit of the L-type Ca2+ channel (cacna1c) as well as the expression of splice variants of its exon 1 that contribute to specificity of ICaL in different tissue such as cardiac myocytes or smooth muscle. 24 h incubation without pacing decreased ICaL density by ~ 10% only. Consistent with this decrease we observed a decrease in the expression of total cacna1c and of exon 1a, the dominant variant of cardiomyocytes, while expression of exon 1b and 1c increased. Pacing for 24 h at 1 and 3 Hz led to a substantial decrease in ICaL density by 30%, mildly slowed ICaL inactivation and shifted steady-state inactivation to more negative potentials. Total cacna1c mRNA expression was substantially decreased by pacing, as was the expression of exon 1b and 1c. Taken together, electrical silence introduces fewer alterations in ICaL density and cacna1c mRNA expression than pacing for 24 h and should therefore be the preferred approach for primary culture of cardiomyocytes.
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Affiliation(s)
- Anne Ritzer
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstraße 6, 91054, Erlangen, Germany
| | - Tobias Roeschl
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstraße 6, 91054, Erlangen, Germany
| | - Sandra Nay
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstraße 6, 91054, Erlangen, Germany
| | - Elena Rudakova
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstraße 6, 91054, Erlangen, Germany
| | - Tilmann Volk
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstraße 6, 91054, Erlangen, Germany.
- Muscle Research Center Erlangen (MURCE), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany.
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Desantis V, Potenza MA, Sgarra L, Nacci C, Scaringella A, Cicco S, Solimando AG, Vacca A, Montagnani M. microRNAs as Biomarkers of Endothelial Dysfunction and Therapeutic Target in the Pathogenesis of Atrial Fibrillation. Int J Mol Sci 2023; 24:5307. [PMID: 36982382 PMCID: PMC10049145 DOI: 10.3390/ijms24065307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/12/2023] Open
Abstract
The pathophysiology of atrial fibrillation (AF) may involve atrial fibrosis/remodeling and dysfunctional endothelial activities. Despite the currently available treatment approaches, the progression of AF, its recurrence rate, and the high mortality risk of related complications underlay the need for more advanced prognostic and therapeutic strategies. There is increasing attention on the molecular mechanisms controlling AF onset and progression points to the complex cell to cell interplay that triggers fibroblasts, immune cells and myofibroblasts, enhancing atrial fibrosis. In this scenario, endothelial cell dysfunction (ED) might play an unexpected but significant role. microRNAs (miRNAs) regulate gene expression at the post-transcriptional level. In the cardiovascular compartment, both free circulating and exosomal miRNAs entail the control of plaque formation, lipid metabolism, inflammation and angiogenesis, cardiomyocyte growth and contractility, and even the maintenance of cardiac rhythm. Abnormal miRNAs levels may indicate the activation state of circulating cells, and thus represent a specific read-out of cardiac tissue changes. Although several unresolved questions still limit their clinical use, the ease of accessibility in biofluids and their prognostic and diagnostic properties make them novel and attractive biomarker candidates in AF. This article summarizes the most recent features of AF associated with miRNAs and relates them to potentially underlying mechanisms.
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Affiliation(s)
- Vanessa Desantis
- Department of Precision and Regenerative Medicine and Ionian Area, Pharmacology Section, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Maria Assunta Potenza
- Department of Precision and Regenerative Medicine and Ionian Area, Pharmacology Section, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Luca Sgarra
- General Hospital “F. Miulli” Acquaviva delle Fonti, 70021 Bari, Italy
| | - Carmela Nacci
- Department of Precision and Regenerative Medicine and Ionian Area, Pharmacology Section, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Antonietta Scaringella
- Department of Precision and Regenerative Medicine and Ionian Area, Pharmacology Section, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Sebastiano Cicco
- Department of Precision and Regenerative Medicine and Ionian Area, Unit of Internal Medicine and Clinical Oncology, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Antonio Giovanni Solimando
- Department of Precision and Regenerative Medicine and Ionian Area, Unit of Internal Medicine and Clinical Oncology, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Angelo Vacca
- Department of Precision and Regenerative Medicine and Ionian Area, Unit of Internal Medicine and Clinical Oncology, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
| | - Monica Montagnani
- Department of Precision and Regenerative Medicine and Ionian Area, Pharmacology Section, University of Bari Aldo Moro Medical School, 70124 Bari, Italy
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Hao H, Dai C, Han X, Li Y. A novel therapeutic strategy for alleviating atrial remodeling by targeting exosomal miRNAs in atrial fibrillation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119365. [PMID: 36167158 DOI: 10.1016/j.bbamcr.2022.119365] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 08/29/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
Atrial fibrillation (AF) is one of the most frequent cardiac arrhythmias, and atrial remodeling is related to the progression of AF. Although several therapeutic approaches have been presented in recent years, the continuously increasing mortality rate suggests that more advanced strategies for treatment are urgently needed. Exosomes regulate pathological processes through intercellular communication mediated by microribonucleic acid (miRNA) in various cardiovascular diseases (CVDs). Exosomal miRNAs associated with signaling pathways have added more complexity to an already complex direct cell-to-cell interaction. Exosome delivery of miRNAs is involved in cardiac regeneration and cardiac protection. Recent studies have found that exosomes play a critical role in the diagnosis and treatment of cardiac fibrosis. By improving exosome stability and modifying surface epitopes, specific pharmaceutical agents can be supplied to improve tropism and targeting to cells and tissues in vivo. Exosomes harboring miRNAs may have clinical utility in cell-free therapeutic approaches and may serve as prognostic and diagnostic biomarkers for AF. Currently, limitations challenge pharmaceutic design, therapeutic utility and in vivo targeted delivery to patients. The aim of this article is to review the developmental features of AF associated with exosomal miRNAs and relate them to underlying mechanisms.
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Affiliation(s)
- Hongting Hao
- Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China
| | - Chenguang Dai
- Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China
| | - Xuejie Han
- Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China
| | - Yue Li
- Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China; NHC Key Laboratory of Cell Translation, Harbin Medical University, Heilongjiang 150001, China; Key Laboratory of Hepatosplenic Surgery, Harbin Medical University, Ministry of Education, Harbin 150001, China; Key Laboratory of Cardiac Diseases and Heart Failure, Harbin Medical University, Harbin 150001, China; Heilongjiang Key Laboratory for Metabolic Disorder & Cancer Related Cardiovascular Diseases, Harbin 150081, China; Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin, China.
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8
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Sung DJ, Jeon YK, Choi J, Kim B, Golpasandi S, Park SW, Oh SB, Bae YM. Protective effect of low-intensity treadmill exercise against acetylcholine-calcium chloride-induced atrial fibrillation in mice. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2022; 26:313-323. [PMID: 36039732 PMCID: PMC9437371 DOI: 10.4196/kjpp.2022.26.5.313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
Atrial fibrillation (AF) is the most common supraventricular arrhythmia, and it corresponds highly with exercise intensity. Here, we induced AF in mice using acetylcholine (ACh)-CaCl2 for 7 days and aimed to determine the appropriate exercise intensity (no, low, moderate, high) to protect against AF by running the mice at different intensities for 4 weeks before the AF induction by ACh-CaCl2. We examined the AF-induced atrial remodeling using electrocardiogram, patch-clamp, and immunohistochemistry. After the AF induction, heart rate, % increase of heart rate, and heart weight/body weight ratio were significantly higher in all the four AF groups than in the normal control; highest in the high-ex AF and lowest in the low-ex (lower than the no-ex AF), which indicates that low-ex treated the AF. Consistent with these changes, G protein-gated inwardly rectifying K+ currents, which were induced by ACh, increased in an exercise intensity-dependent manner and were lower in the low-ex AF than the no-ex AF. The peak level of Ca2+ current (at 0 mV) increased also in an exercise intensity-dependent manner and the inactivation time constants were shorter in all AF groups except for the low-ex AF group, in which the time constant was similar to that of the control. Finally, action potential duration was shorter in all the four AF groups than in the normal control; shortest in the high-ex AF and longest in the low-ex AF. Taken together, we conclude that low-intensity exercise protects the heart from AF, whereas high-intensity exercise might exacerbate AF.
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Affiliation(s)
- Dong-Jun Sung
- Department of Sport and Health Studies, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea
- Sports Convergence Institute, Chungju 27478, Korea
- Center for Metabolic Diseases, Konkuk University, Chungju 27478, Korea
| | - Yong-Kyun Jeon
- Department of Physical Education at the Graduate School of Education, Dankook University, Yongin 16890, Korea
| | - Jaeil Choi
- Department of Physical Education at the Graduate School of Education, Dankook University, Yongin 16890, Korea
| | - Bokyung Kim
- Department of Physiology, KU Open Innovation Center, Research Institute of Medical Science, Konkuk University School of Medicine, Chungju 27478, Korea
| | - Shadi Golpasandi
- Department of Physiology, KU Open Innovation Center, Research Institute of Medical Science, Konkuk University School of Medicine, Chungju 27478, Korea
| | - Sang Woong Park
- Department of Emergency Medical Services, College of Health Sciences, Eulji University, Seongam 13135, Korea
| | - Seung-Bum Oh
- Department of Sport and Health Studies, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea
| | - Young Min Bae
- Department of Physiology, KU Open Innovation Center, Research Institute of Medical Science, Konkuk University School of Medicine, Chungju 27478, Korea
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Aimoto M, Yagi K, Ezawa A, Tsuneoka Y, Kumada K, Hasegawa T, Kuze T, Chiba T, Nagasawa Y, Tanaka H, Takahara A. Chronic Volume Overload Caused by Abdominal Aorto-Venocaval Shunt Provides Arrhythmogenic Substrates in the Rat Atrium. Biol Pharm Bull 2022; 45:635-642. [DOI: 10.1248/bpb.b22-00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Megumi Aimoto
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Keita Yagi
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Aya Ezawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Yayoi Tsuneoka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University
| | - Kohei Kumada
- Department of R&D, Fukushima Research Laboratories, TOA EIYO LTD
| | - Takeshi Hasegawa
- Department of R&D, Fukushima Research Laboratories, TOA EIYO LTD
| | - Tetsuo Kuze
- Department of R&D, Fukushima Research Laboratories, TOA EIYO LTD
| | - Toshiki Chiba
- Department of R&D, Fukushima Research Laboratories, TOA EIYO LTD
| | - Yoshinobu Nagasawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Hikaru Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University
| | - Akira Takahara
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
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10
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Kabakov AY, Sengun E, Lu Y, Roder K, Bronk P, Baggett B, Turan NN, Moshal KS, Koren G. Three-Week-Old Rabbit Ventricular Cardiomyocytes as a Novel System to Study Cardiac Excitation and EC Coupling. Front Physiol 2021; 12:672360. [PMID: 34867432 PMCID: PMC8637404 DOI: 10.3389/fphys.2021.672360] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 10/06/2021] [Indexed: 01/14/2023] Open
Abstract
Cardiac arrhythmias significantly contribute to cardiovascular morbidity and mortality. The rabbit heart serves as an accepted model system for studying cardiac cell excitation and arrhythmogenicity. Accordingly, primary cultures of adult rabbit ventricular cardiomyocytes serve as a preferable model to study molecular mechanisms of human cardiac excitation. However, the use of adult rabbit cardiomyocytes is often regarded as excessively costly. Therefore, we developed and characterized a novel low-cost rabbit cardiomyocyte model, namely, 3-week-old ventricular cardiomyocytes (3wRbCMs). Ventricular myocytes were isolated from whole ventricles of 3-week-old New Zealand White rabbits of both sexes by standard enzymatic techniques. Using wheat germ agglutinin, we found a clear T-tubule structure in acutely isolated 3wRbCMs. Cells were adenovirally infected (multiplicity of infection of 10) to express Green Fluorescent Protein (GFP) and cultured for 48 h. The cells showed action potential duration (APD90 = 253 ± 24 ms) and calcium transients similar to adult rabbit cardiomyocytes. Freshly isolated and 48-h-old-cultured cells expressed critical ion channel proteins: calcium voltage-gated channel subunit alpha1 C (Cavα1c), sodium voltage-gated channel alpha subunit 5 (Nav1.5), potassium voltage-gated channel subfamily D member 3 (Kv4.3), and subfamily A member 4 (Kv1.4), and also subfamily H member 2 (RERG. Kv11.1), KvLQT1 (K7.1) protein and inward-rectifier potassium channel (Kir2.1). The cells displayed an appropriate electrophysiological phenotype, including fast sodium current (I Na), transient outward potassium current (I to), L-type calcium channel peak current (I Ca,L), rapid and slow components of the delayed rectifier potassium current (I Kr and I Ks), and inward rectifier (I K1). Although expression of the channel proteins and some currents decreased during the 48 h of culturing, we conclude that 3wRbCMs are a new, low-cost alternative to the adult-rabbit-cardiomyocytes system, which allows the investigation of molecular mechanisms of cardiac excitation on morphological, biochemical, genetic, physiological, and biophysical levels.
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Affiliation(s)
- Anatoli Y. Kabakov
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Elif Sengun
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Department of Pharmacology, Institute of Graduate Studies in Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Yichun Lu
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Karim Roder
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Peter Bronk
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Brett Baggett
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Nilüfer N. Turan
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Karni S. Moshal
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Gideon Koren
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
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11
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Zhang T, Wu Y, Hu Z, Xing W, Kun LV, Wang D, Hu N. Small-Molecule Integrated Stress Response Inhibitor Reduces Susceptibility to Postinfarct Atrial Fibrillation in Rats via the Inhibition of Integrated Stress Responses. J Pharmacol Exp Ther 2021; 378:197-206. [PMID: 34215702 DOI: 10.1124/jpet.121.000491] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/23/2021] [Indexed: 11/22/2022] Open
Abstract
Phosphorylation of the eukaryotic translation initiation factor 2 α-subunit, which subsequently upregulates activating transcription factor 4 (ATF4), is the core event in the integrated stress response (ISR) pathway. Previous studies indicate phosphorylation of eukaryotic translation initiation factor 2 ɑ-subunit in atrial tissue in response to atrial fibrillation (AF). This study investigated the role of ISR pathway in experimental AF by using a small-molecule ISR inhibitor (ISRIB). Accordingly, rats were subjected to coronary artery occlusion to induce myocardial infarction (MI), or sham operation, and received either trans-ISRIB (2 mg/kg/d, i.p.) or vehicle for seven days. Thereafter, animals were subjected to the AF inducibility test by transesophageal rapid burst pacing followed by procurement of left atrium (LA) for assessment of atrial fibrosis, inflammatory indices, autophagy-related proteins, ISR activation, ion channel, and connexin 43 expression. Results showed a significant increase in the AF vulnerability and the activation of ISR in LA as evidenced by enhanced eukaryotic translation initiation factor 2 ɑ-subunit phosphorylation. ISRIB treatment suppressed upregulation of ATF4, fibrosis as indexed by determination of α-smooth muscle actin and collagen levels, inflammatory macrophage infiltration (i.e., CD68 and inducible nitric oxide synthase/CD68-positive macrophage), and autophagy as determined by expression of light chain 3. Further, ISRIB treatment reversed the expression of relevant ion channel (i.e., the voltage-gated sodium channel 1.5 , L-type voltage-dependent calcium channel 1.2, and voltage-activated A-type potassium ion channel 4.3) and connexin 43 remodeling. Collectively, the results suggest that the ISR is a key pathway in pathogenesis of AF, post-MI, and represents a novel target for treatment of AF. SIGNIFICANCE STATEMENT: The activation of integrated stress response (ISR) pathway as evidenced by enhanced eukaryotic translation initiation factor 2 ɑ-subunit phosphorylation in left atrium plays a key role in atrial fibrillation (AF). ISR inhibitor (ISRIB) reduces AF occurrence and atrial proarrhythmogenic substrate. The beneficial action of ISRIB may be mediated by suppressing ISR pathway-related cardiac fibrosis, inflammatory macrophage infiltration, autophagy, and restoring the expression of ion channel and connexin 43. This study suggests a key dysfunctional role for ISR in pathogenesis of AF with implications for novel treatment.
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Affiliation(s)
- Ting Zhang
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
| | - Yong Wu
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
| | - Zhengtao Hu
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
| | - Wen Xing
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
| | - L V Kun
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
| | - Deguo Wang
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
| | - Nengwei Hu
- Department of Gerontology (T.Z., Y.W., Z.H., W.X., D.W., N.H.) and Key Laboratory of Non-Coding RNA Transformation Research of Anhui Higher Education Institution (W.X., K.L., D.W., N.H.), First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, Anhui, China; Department of Psychology, Wannan Medical College, Wuhu, Anhui, China (T.Z.); and Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland (N.H.)
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12
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Marian AJ, Asatryan B, Wehrens XHT. Genetic basis and molecular biology of cardiac arrhythmias in cardiomyopathies. Cardiovasc Res 2021; 116:1600-1619. [PMID: 32348453 DOI: 10.1093/cvr/cvaa116] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/09/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias are common, often the first, and sometimes the life-threatening manifestations of hereditary cardiomyopathies. Pathogenic variants in several genes known to cause hereditary cardiac arrhythmias have also been identified in the sporadic cases and small families with cardiomyopathies. These findings suggest a shared genetic aetiology of a subset of hereditary cardiomyopathies and cardiac arrhythmias. The concept of a shared genetic aetiology is in accord with the complex and exquisite interplays that exist between the ion currents and cardiac mechanical function. However, neither the causal role of cardiac arrhythmias genes in cardiomyopathies is well established nor the causal role of cardiomyopathy genes in arrhythmias. On the contrary, secondary changes in ion currents, such as post-translational modifications, are common and contributors to the pathogenesis of arrhythmias in cardiomyopathies through altering biophysical and functional properties of the ion channels. Moreover, structural changes, such as cardiac hypertrophy, dilatation, and fibrosis provide a pro-arrhythmic substrate in hereditary cardiomyopathies. Genetic basis and molecular biology of cardiac arrhythmias in hereditary cardiomyopathies are discussed.
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Affiliation(s)
- Ali J Marian
- Department of Medicine, Center for Cardiovascular Genetics, Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, 6770 Bertner Street, Suite C900A, Houston, TX 77030, USA
| | - Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Xander H T Wehrens
- Department of Biophysics and Molecular Physiology, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
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13
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Xiang K, Akram M, Elbossaty WF, Yang J, Fan C. Exosomes in atrial fibrillation: therapeutic potential and role as clinical biomarkers. Heart Fail Rev 2021; 27:1211-1221. [PMID: 34251579 DOI: 10.1007/s10741-021-10142-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/05/2021] [Indexed: 12/21/2022]
Abstract
Atrial fibrillation (AF), the most common cardiac arrhythmia, is a global epidemic. AF can cause heart failure and myocardial infarction and increase the risk of stroke, disability, and thromboembolic events. AF is becoming increasingly ubiquitous and is associated with increased morbidity and mortality at higher ages, resulting in an increasing threat to human health as well as substantial medical and social costs. Currently, treatment strategies for AF focus on controlling heart rate and rhythm with medications to restore and maintain sinus rhythm, but this approach has limitations. Catheter ablation is not entirely satisfactory and does not address the issues underlying AF. Research exploring the mechanisms causing AF is urgently needed for improved prevention, diagnosis, and treatment of AF. Exosomes are small vesicles (30-150 nm) released by cells that transmit information between cells. MicroRNAs in exosomes play an important role in the pathogenesis of AF and are established as a biomarker for AF. In this review, a summary of the role of exosomes in AF is presented. The role of exosomes and microRNAs in AF occurrence, their therapeutic potential, and their potential role as clinical biomarkers is considered. A better understanding of exosomes has the potential to improve the prognosis of AF patients worldwide, reducing the global medical burden of this disease.
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Affiliation(s)
- Kun Xiang
- Department of Cardiovascular Surgery, the Second Xiangya Hospital, Central South University, Middle Renmin Road 139, Changsha, 410011, China
| | - Muhammad Akram
- Department of Eastern Medicine, Government College University Faisalabad, Faisalabad, Pakistan
| | | | - Jinfu Yang
- Department of Cardiovascular Surgery, the Second Xiangya Hospital, Central South University, Middle Renmin Road 139, Changsha, 410011, China
| | - Chengming Fan
- Department of Cardiovascular Surgery, the Second Xiangya Hospital, Central South University, Middle Renmin Road 139, Changsha, 410011, China.
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14
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Wang X, Chen X, Dobrev D, Li N. The crosstalk between cardiomyocyte calcium and inflammasome signaling pathways in atrial fibrillation. Pflugers Arch 2021; 473:389-405. [PMID: 33511453 DOI: 10.1007/s00424-021-02515-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 02/07/2023]
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmia in adults. The prevalence and incidence of AF is going to increase substantially over the next few decades. Because AF increases the risk of stroke, heart failure, dementia, and others, it severely impacts the quality of life, morbidity, and mortality. Although the pathogenesis of AF is multifaceted and complex, focal ectopic activity and reentry are considered as the fundamental proarrhythmic mechanisms underlying AF development. Over the past 2 decades, large amount of evidence points to the key role of intracellular Ca2+ dysregulation in both initiation and maintenance of AF. More recently, emerging evidence reveal that NLRP3 (NACHT, LRR, PYD domain-containing 3) inflammasome pathway contributes to the substrate of both triggered activity and reentry, ultimately promoting AF. In this article, we review the current state of knowledge on Ca2+ signaling and NLRP3 inflammasome activity in AF. We also discuss the potential crosstalk between these two quintessential contributors to AF promotion.
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Affiliation(s)
- Xiaolei Wang
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA
| | - Xiaohui Chen
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Na Li
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA. .,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA. .,Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.
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15
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Li S, Gao Y, Liu Y, Li J, Yang X, Hu R, Liu J, Zhang Y, Zuo K, Li K, Yin X, Chen M, Zhong J, Yang X. Myofibroblast-Derived Exosomes Contribute to Development of a Susceptible Substrate for Atrial Fibrillation. Cardiology 2020; 145:324-332. [PMID: 32235120 DOI: 10.1159/000505641] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/21/2019] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Atrial fibrosis plays a critical role in atrial fibrillation (AF). A key event in the pathogenesis of fibrosis is the activation of fibroblasts (FBs) into myofibroblasts (MFBs). Paracrine factors released from MFBs lead to ion channel expression changes in cardiomyocytes (CMs). Downregulation of L-type calcium channel Cav1.2 expression is a hallmark of AF-associated ionic remodeling. However, whether exosome (Exo)-mediated crosstalk between MFBs and CMs regulates Cav1.2 expression remains unknown. METHODS Atrial FBs and CMs were isolated and cultured from neonatal rats by enzymatic digestion. The activation of FBs into MFBs was induced by angiotensin II. Co-culture assay and in vitro Exo treatment were used to determine the effect of MFB-derived Exos on Cav1.2 expression. Confocal Ca2+ imaging was performed to examine the adrenergic stimulation-elicited Ca2+ influx signals. The levels of potential Cav1.2-inhibitory microRNAs (miRNAs) were measured by qRT-PCR. RESULTS Untreated FBs expressed limited amounts of alpha smooth muscle actin (α-SMA), while angiotensin II induced a significant upregulation of α-SMA-expressing MFBs. Co-cultures of MFBs and CMs resulted in downregulation of Cav1.2 expression in CMs, which was largely abolished by pretreatment of MFBs with exosomal inhibitor GW4869. More importantly, treatment with MFB-derived Exos caused repression of Cav1.2 expression in CMs. Additionally, the adrenergic receptor agonist-elicited Ca2+ influx signals in CMs were remarkably attenuated by pretreatment with MFB-derived Exos, corresponding to the paralleled change in Cav1.2 expression. Finally, miR-21-3p, a potential Cav1.2-inhibitory miRNA, was enriched in MFB-derived Exos and upregulated in CMs in response to MFB-derived Exos. CONCLUSION We uncover an Exo-mediated crosstalk between MFBs and CMs, contributing to increased vulnerability to AF by reducing the expression of Cav1.2 in CMs.
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Affiliation(s)
- Shichao Li
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Yuanfeng Gao
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Ye Liu
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Jing Li
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Xiyan Yang
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Roumu Hu
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Jia Liu
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Yuan Zhang
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Kun Zuo
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Kuibao Li
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Xiandong Yin
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Mulei Chen
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Jiuchang Zhong
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China,
| | - Xinchun Yang
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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16
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Yuxiang L, Fujiu K. Frozen Heart and Arrhythmia. Int Heart J 2019; 60:1019-1021. [PMID: 31564707 DOI: 10.1536/ihj.19-407] [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: 11/18/2022]
Affiliation(s)
- Liu Yuxiang
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Katsuhito Fujiu
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo.,Department of Advanced Cardiology, Graduate School of Medicine, The University of Tokyo
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17
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Zhao H, Li T, Liu G, Zhang L, Li G, Yu J, Lou Q, He R, Zhan C, Li L, Yang W, Zang Y, Cheng C, Li W. Chronic B-Type Natriuretic Peptide Therapy Prevents Atrial Electrical Remodeling in a Rabbit Model of Atrial Fibrillation. J Cardiovasc Pharmacol Ther 2019; 24:575-585. [PMID: 31159577 DOI: 10.1177/1074248419854749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is an important and growing clinical problem. Current pharmacological treatments are unsatisfactory. Electrical remodeling has been identified as one of the principal pathophysiological mechanisms that promote AF, but there are no effective therapies to prevent or correct electrical remodeling in patients with AF. In AF, cardiac production and circulating levels of B-type natriuretic peptide (BNP) are increased. However, its functional significance in AF remains to be determined. We assessed the hypotheses that chronic BNP treatment may prevent the altered electrophysiology in AF, and preventing AF-induced activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) may play a role. METHODS AND RESULTS Forty-four rabbits were randomly divided into sham, rapid atrial pacing (RAP at 600 beats/min for 3 weeks), RAP/BNP, and sham/BNP groups. Rabbits in the RAP/BNP and sham/BNP groups received subcutaneous BNP (20 μg/kg twice daily) during the 3-week study period. HL-1 cells were subjected to rapid field stimulation for 24 hours in the presence or absence of BNP, KN-93 (a CaMKII inhibitor), or KN-92 (a nonactive analog of KN-93). We compared atrial electrical remodeling-related alterations in the ion channel/function/expression of these animals. We found that only in the RAP group, AF inducibility was significantly increased, atrial effective refractory periods and action potential duration were reduced, and the density of I Ca, L and I to decreased, while I K1 increased. The changes in the expressions of Cav1.2, Kv4.3, and Kir2.1 and currents showed a similar trend. In addition, in the RAP group, the activation of CaMKIIδ and phosphorylation of ryanodine receptor 2 and phospholamban significantly increased. Importantly, these changes were prevented in the RAP/BNP group, which were further validated by in vitro studies. CONCLUSIONS Chronic BNP therapy prevents atrial electrical remodeling in AF. Inhibition of CaMKII activation plays an important role to its anti-AF efficacy in this model.
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Affiliation(s)
- Hongyan Zhao
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.,2 Department of Cardiology, The People's Hospital of Liaoning Province, Shenyang, China
| | - Tiankai Li
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Guangzhong Liu
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Li Zhang
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Guangnan Li
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Jia Yu
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Qi Lou
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Rui He
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Chengchuang Zhan
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Luyifei Li
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Wen Yang
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yanxiang Zang
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Cheping Cheng
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.,3 Department of Internal Medicine, Section on Cardiovascular Medicine, and Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Weimin Li
- 1 Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
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18
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Liraglutide suppresses atrial electrophysiological changes. Heart Vessels 2019; 34:1389-1393. [DOI: 10.1007/s00380-018-01327-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/21/2018] [Indexed: 12/29/2022]
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19
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Kosch TA, Silva CNS, Brannelly LA, Roberts AA, Lau Q, Marantelli G, Berger L, Skerratt LF. Genetic potential for disease resistance in critically endangered amphibians decimated by chytridiomycosis. Anim Conserv 2018. [DOI: 10.1111/acv.12459] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- T. A. Kosch
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
| | - C. N. S. Silva
- Centre for Sustainable Tropical Fisheries and Aquaculture College of Science and Engineering James Cook University Townsville Qld Australia
| | - L. A. Brannelly
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
- Department of Biological Sciences University of Pittsburgh Pittsburgh PA USA
| | - A. A. Roberts
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
| | - Q. Lau
- Department of Evolutionary Studies of Biosystems Sokendai (The Graduate University for Advanced Studies) Hayama Japan
| | | | - L. Berger
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
| | - L. F. Skerratt
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
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20
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Denham NC, Pearman CM, Caldwell JL, Madders GWP, Eisner DA, Trafford AW, Dibb KM. Calcium in the Pathophysiology of Atrial Fibrillation and Heart Failure. Front Physiol 2018; 9:1380. [PMID: 30337881 PMCID: PMC6180171 DOI: 10.3389/fphys.2018.01380] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/11/2018] [Indexed: 12/20/2022] Open
Abstract
Atrial fibrillation (AF) is commonly associated with heart failure. A bidirectional relationship exists between the two-AF exacerbates heart failure causing a significant increase in heart failure symptoms, admissions to hospital and cardiovascular death, while pathological remodeling of the atria as a result of heart failure increases the risk of AF. A comprehensive understanding of the pathophysiology of AF is essential if we are to break this vicious circle. In this review, the latest evidence will be presented showing a fundamental role for calcium in both the induction and maintenance of AF. After outlining atrial electrophysiology and calcium handling, the role of calcium-dependent afterdepolarizations and atrial repolarization alternans in triggering AF will be considered. The atrial response to rapid stimulation will be discussed, including the short-term protection from calcium overload in the form of calcium signaling silencing and the eventual progression to diastolic calcium leak causing afterdepolarizations and the development of an electrical substrate that perpetuates AF. The role of calcium in the bidirectional relationship between heart failure and AF will then be covered. The effects of heart failure on atrial calcium handling that promote AF will be reviewed, including effects on both atrial myocytes and the pulmonary veins, before the aspects of AF which exacerbate heart failure are discussed. Finally, the limitations of human and animal studies will be explored allowing contextualization of what are sometimes discordant results.
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Affiliation(s)
- Nathan C. Denham
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | | | | | | | | | | | - Katharine M. Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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21
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Ashikaga H, James RG. Inter-scale information flow as a surrogate for downward causation that maintains spiral waves. CHAOS (WOODBURY, N.Y.) 2018; 28:075306. [PMID: 30070515 DOI: 10.1063/1.5017534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A rotor, the rotation center of spiral waves, has been proposed as a causal mechanism to maintain atrial fibrillation (AF) in human. However, our current understanding of the causality between rotors and spiral waves remains incomplete. One approach to improving our understanding is to determine the relationship between rotors and downward causation from the macro-scale collective behavior of spiral waves to the micro-scale behavior of individual components in a cardiac system. This downward causation is quantifiable as inter-scale information flow that can be used as a surrogate for the mechanism that maintains spiral waves. We used a numerical model of a cardiac system and generated a renormalization group with system descriptions at multiple scales. We found that transfer entropy quantified the upward and downward inter-scale information flow between micro- and macro-scale descriptions of the cardiac system with spiral waves. In addition, because the spatial profile of transfer entropy and intrinsic transfer entropy was identical, there were no synergistic effects in the system. Furthermore, inter-scale information flow significantly decreased as the description of the system became more macro-scale. Finally, downward information flow was significantly correlated with the number of rotors, but the higher numbers of rotors were not necessarily associated with higher downward information flow. This finding contradicts the concept that the rotors are the causal mechanism that maintains spiral waves, and may account for the conflicting evidence from clinical studies targeting rotors to eliminate AF.
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Affiliation(s)
- Hiroshi Ashikaga
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, F-33600 Pessac-Bordeaux, France
| | - Ryan G James
- Department of Physics, Complexity Sciences Center, University of California, Davis, One Shields Avenue, Davis, California 95616-8572, USA
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22
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Cheng H, Cannell MB, Hancox JC. Differential responses of rabbit ventricular and atrial transient outward current (I to) to the I to modulator NS5806. Physiol Rep 2017; 5:5/5/e13172. [PMID: 28270595 PMCID: PMC5350179 DOI: 10.14814/phy2.13172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 02/06/2023] Open
Abstract
Transient outward potassium current (Ito) in the heart underlies phase 1 repolarization of cardiac action potentials and thereby affects excitation–contraction coupling. Small molecule activators of Ito may therefore offer novel treatments for cardiac dysfunction, including heart failure and atrial fibrillation. NS5806 has been identified as a prototypic activator of canine Ito. This study investigated, for the first time, actions of NS5806 on rabbit atrial and ventricular Ito. Whole cell patch‐clamp recordings of Ito and action potentials were made at physiological temperature from rabbit ventricular and atrial myocytes. 10 μmol/L NS5806 increased ventricular Ito with a leftward shift in Ito activation and accelerated restitution. At higher concentrations, stimulation of Ito was followed by inhibition. The EC50 for stimulation was 1.6 μmol/L and inhibition had an IC50 of 40.7 μmol/L. NS5806 only inhibited atrial Ito (IC50 of 18 μmol/L) and produced a modest leftward shifts in Ito activation and inactivation, without an effect on restitution. 10 μmol/L NS5806 shortened ventricular action potential duration (APD) at APD20‐APD90 but prolonged atrial APD. NS5806 also reduced atrial AP upstroke and amplitude, consistent with an additional atrio‐selective effect on Na+ channels. In contrast to NS5806, flecainide, which discriminates between Kv1.4 and 4.x channels, produced similar levels of inhibition of ventricular and atrial Ito. NS5806 discriminates between rabbit ventricular and atrial Ito, with mixed activator and inhibitor actions on the former and inhibitor actions against the later. NS5806 may be of significant value for pharmacological interrogation of regional differences in native cardiac Ito.
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Affiliation(s)
- Hongwei Cheng
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, U.K
| | - Mark B Cannell
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, U.K
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, U.K
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23
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Cheng W, Zhu Y, Wang H. The MAPK pathway is involved in the regulation of rapid pacing-induced ionic channel remodeling in rat atrial myocytes. Mol Med Rep 2016; 13:2677-82. [PMID: 26847818 DOI: 10.3892/mmr.2016.4862] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 01/11/2016] [Indexed: 11/06/2022] Open
Abstract
Alterations to the expression L‑type calcium channels (LTCCs) and Kv4.3 potassium channels form the possible basis of atrial electrical remodeling during rapid pacing. The mitogen‑activated protein kinase (MAPK) pathway is affected by increases in cytoplasmic Ca2+, and therefore represents an attractive candidate for the regulation and mediation of Ca2+‑induced ion channel remodeling. The present study aimed to investigate alterations to the ion channel‑MAPK axis, and to determine its influence on ion channel remodeling during atrial fibrillation. Rat atrial myocytes were isolated, cultured, and in vitro rapid pacing was established. Intracellular Ca2+ signals were monitored using the Fluo‑3/AM Ca2+ indicator. Verapamil, PD98058 and SB203580 were added to the culture medium of various groups at specific time‑points. The mRNA expression levels of LTCC‑α1c and Kv4.3 potassium channels were detected by reverse transcription‑polymerase chain reaction. Western blotting was performed to determine the expression levels of channel and signaling proteins. The results demonstrated that fast pacing significantly increased the intracellular Ca2+ concentration in atrial myocytes, whereas treatment with verapamil markedly inhibited this increase. In addition, verapamil significantly antagonized the rapid pacing‑induced activation of extracellular signal‑regulated kinase (ERK) and p38MAPK. These results indicated that the MAPK pathway may have an important role in the opening of LTCCs, and alterations to MAPK molecule expression could affect the expression and remodeling of ion channels.
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Affiliation(s)
- Wei Cheng
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Yun Zhu
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Haidong Wang
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
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24
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Vagal atrial fibrillation: What is it and should we treat it? Int J Cardiol 2015; 201:415-21. [DOI: 10.1016/j.ijcard.2015.08.108] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/15/2015] [Accepted: 08/09/2015] [Indexed: 12/18/2022]
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Atrial overexpression of angiotensin-converting enzyme 2 improves the canine rapid atrial pacing-induced structural and electrical remodeling. Fan, ACE2 improves atrial substrate remodeling. Basic Res Cardiol 2015; 110:45. [PMID: 26143546 PMCID: PMC7101981 DOI: 10.1007/s00395-015-0499-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 05/17/2015] [Accepted: 05/26/2015] [Indexed: 01/30/2023]
Abstract
The purpose of this study was to investigate whether atrial overexpression of angiotensin-converting enzyme 2 (ACE2) by homogeneous transmural atrial gene transfer can reverse atrial remodeling and its mechanisms in a canine atrial-pacing model. Twenty-eight mongrel dogs were randomly divided into four groups: Sham-operated, AF-control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP) and gene therapy with Ad-ACE2 (Ad-ACE2) (n = 7 per subgroup). AF was induced in all dogs except the Sham-operated group by rapid atrial pacing at 450 beats/min for 2 weeks. Ad-EGFP and Ad-ACE2 group then received epicardial gene painting. Three weeks after gene transfer, all animals except the Sham group underwent rapid atrial pacing for another 3 weeks and then invasive electrophysiological, histological and molecular studies. The Ad-ACE2 group showed an increased ACE2 and Angiotensin-(1–7) expression, and decreased Angiotensin II expression in comparison with Ad-EGFP and AF-control group. ACE2 overexpression attenuated rapid atrial pacing-induced increase in activated extracellular signal-regulated kinases and mitogen-activated protein kinases (MAPKs) levels, and decrease in MAPK phosphatase 1(MKP-1) level, resulting in attenuation of atrial fibrosis collagen protein markers and transforming growth factor-β1. Additionally, ACE2 overexpression also modulated the tachypacing-induced up-regulation of connexin 40, down-regulation of connexin 43 and Kv4.2, and significantly decreased the inducibility and duration of AF. ACE2 overexpression could shift the renin–angiotensin system balance towards the protective axis, attenuate cardiac fibrosis remodeling associated with up-regulation of MKP-1 and reduction of MAPKs activities, modulate tachypacing-induced ion channels and connexin remodeling, and subsequently reduce the inducibility and duration of AF.
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Abstract
Atrial fibrillation (AF) and heart failure (HF) are two epidemics of the century that have a close and complex relationship. The mechanisms underlying this association remain an area of ongoing intense research. In this review, we will describe the relationship between these two public health concerns, the mechanisms that fuel the development and perpetuation of both, and the evolving concepts that may revolutionize our approach to this dual epidemic.
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Affiliation(s)
- Christina Luong
- Division of Cardiology, University of British Columbia, 2775 Laurel Street, Vancouver, BC, V5Z 1M9, Canada
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27
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Wolke C, Bukowska A, Goette A, Lendeckel U. Redox control of cardiac remodeling in atrial fibrillation. Biochim Biophys Acta Gen Subj 2014; 1850:1555-65. [PMID: 25513966 DOI: 10.1016/j.bbagen.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a potential cause of thromboembolic events. AF induces significant changes in the electrophysiological properties of atrial myocytes and causes alterations in the structure, metabolism, and function of the atrial tissue. The molecular basis for the development of structural atrial remodeling of fibrillating human atria is still not fully understood. However, increased production of reactive oxygen or nitrogen species (ROS/RNS) and the activation of specific redox-sensitive signaling pathways observed both in patients with and animal models of AF are supposed to contribute to development, progression and self-perpetuation of AF. SCOPE OF REVIEW The present review summarizes the sources and targets of ROS/RNS in the setting of AF and focuses on key redox-sensitive signaling pathways that are implicated in the pathogenesis of AF and function either to aggravate or protect from disease. MAJOR CONCLUSIONS NADPH oxidases and various mitochondrial monooxygenases are major sources of ROS during AF. Besides direct oxidative modification of e.g. ion channels and ion handling proteins that are crucially involved in action potential generation and duration, AF leads to the reversible activation of redox-sensitive signaling pathways mediated by activation of redox-regulated proteins including Nrf2, NF-κB, and CaMKII. Both processes are recognized to contribute to the formation of a substrate for AF and, thus, to increase AF inducibility and duration. GENERAL SIGNIFICANCE AF is a prevalent disease and due to the current demographic developments its socio-economic relevance will further increase. Improving our understanding of the role that ROS and redox-related (patho)-mechanisms play in the development and progression of AF may allow the development of a targeted therapy for AF that surpasses the efficacy of previous general anti-oxidative strategies. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany
| | - Alicja Bukowska
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany
| | - Andreas Goette
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany; Department of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital, D-33098 Paderborn, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany.
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Gu J, Hu W, Liu X. Pioglitazone improves potassium channel remodeling induced by angiotensin II in atrial myocytes. Med Sci Monit Basic Res 2014; 20:153-60. [PMID: 25296378 PMCID: PMC4206483 DOI: 10.12659/msmbr.892450] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND It has been demonstrated that atrial electrical remodeling contributes toward atrial fibrillation (AF) maintenance, and that angiotensin II (AngII) is involved in the pathogenesis of atrial electrical remodeling. Peroxisome proliferator activated receptor-γ (PPAR-γ) agonists have been shown to inhibit atrial electrical remodeling, but the underlying mechanisms are poorly understood. In the present study we investigated the regulating effects of PPAR-g agonist on AngII-induced potassium channel remodeling in atrial myocytes. MATERIAL/METHODS Whole-cell patch-clamp technique was used to record transient outward potassium current (Ito), ultra-rapid delayed rectifier potassium (Ikur), and inward rectifier potassium current (Ik1). Real-time PCR was used to assess potassium channel subunit mRNA expression. RESULTS Compared with the control group, AngII reduced Ito and Ikur current density as well as amplified Ik1 current density, which were partially prevented by pioglitazone. Furthermore, pioglitazone alleviated the downregulation of Ito subunit (Kv 4.2) and Ikur subunit (Kv 1.5), as well as the upregulation of Ik1 subunit (Kir 2.1 and Kir 2.2) mRNA expression stimulated by AngII. CONCLUSIONS These results suggest that pioglitazone exhibits a beneficial effect on AngII-induced potassium channel remodeling. PPAR-γ agonists may be potentially effective up-stream therapies for AF.
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Affiliation(s)
- Jun Gu
- Department of Cardiology, Shanghai Minhang District Central Hospital, Fudan University, Shanghai, China (mainland)
| | - Wei Hu
- Department of Cardiology, Shanghai Minhang District Central Hospital, Fudan University, Shanghai, China (mainland)
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China (mainland)
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29
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Schmitt N, Grunnet M, Olesen SP. Cardiac potassium channel subtypes: new roles in repolarization and arrhythmia. Physiol Rev 2014; 94:609-53. [PMID: 24692356 DOI: 10.1152/physrev.00022.2013] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K+ channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K+ channels drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K+ channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure. The underlying posttranscriptional and posttranslational remodeling of the individual K+ channels changes their activity and significance relative to each other, and they must be viewed together to understand their role in keeping a stable heart rhythm, also under menacing conditions like attacks of reentry arrhythmia.
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30
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Nattel S, Guasch E, Savelieva I, Cosio FG, Valverde I, Halperin JL, Conroy JM, Al-Khatib SM, Hess PL, Kirchhof P, De Bono J, Lip GYH, Banerjee A, Ruskin J, Blendea D, Camm AJ. Early management of atrial fibrillation to prevent cardiovascular complications. Eur Heart J 2014; 35:1448-56. [PMID: 24536084 DOI: 10.1093/eurheartj/ehu028] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | | | - Irina Savelieva
- Division of Clinical Sciences, Cardiovascular Science, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Francisco G Cosio
- Cardiología Department, Hospital Universitario de Getafe, Madrid, Spain
| | - Irene Valverde
- Cardiología Department, Hospital Universitario de Getafe, Madrid, Spain
| | - Jonathan L Halperin
- Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY, USA
| | - Jennifer M Conroy
- Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY, USA
| | - Sana M Al-Khatib
- Cardiology Division, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Paul L Hess
- Cardiology Division, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Paulus Kirchhof
- University of Birmingham Centre for Cardiovascular Sciences, University of Birmingham and Sandwell and West Birmingham NHS Trust, Birmingham, UK Department of Cardiology and Angiology, Hospital of the University of Münster, Münster, Germany German Atrial Fibrillation Competence NETwork (AFNET), Münster, Germany
| | - Joseph De Bono
- University Hospitals Birmingham NHS Trust, Birmingham, UK
| | - Gregory Y H Lip
- University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK
| | - Amitava Banerjee
- University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK
| | - Jeremy Ruskin
- Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Dan Blendea
- Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - A John Camm
- Division of Clinical Sciences, Cardiovascular Science, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
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31
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Martins RP, Kaur K, Hwang E, Ramirez RJ, Willis BC, Filgueiras-Rama D, Ennis SR, Takemoto Y, Ponce-Balbuena D, Zarzoso M, O'Connell RP, Musa H, Guerrero-Serna G, Avula UMR, Swartz MF, Bhushal S, Deo M, Pandit SV, Berenfeld O, Jalife J. Dominant frequency increase rate predicts transition from paroxysmal to long-term persistent atrial fibrillation. Circulation 2014; 129:1472-82. [PMID: 24463369 DOI: 10.1161/circulationaha.113.004742] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Little is known about the mechanisms underlying the transition from paroxysmal to persistent atrial fibrillation (AF). In an ovine model of long-standing persistent AF we tested the hypothesis that the rate of electric and structural remodeling, assessed by dominant frequency (DF) changes, determines the time at which AF becomes persistent. METHODS AND RESULTS Self-sustained AF was induced by atrial tachypacing. Seven sheep were euthanized 11.5±2.3 days after the transition to persistent AF and without reversal to sinus rhythm; 7 sheep were euthanized after 341.3±16.7 days of long-standing persistent AF. Seven sham-operated animals were in sinus rhythm for 1 year. DF was monitored continuously in each group. Real-time polymerase chain reaction, Western blotting, patch clamping, and histological analyses were used to determine the changes in functional ion channel expression and structural remodeling. Atrial dilatation, mitral valve regurgitation, myocyte hypertrophy, and atrial fibrosis occurred progressively and became statistically significant after the transition to persistent AF, with no evidence for left ventricular dysfunction. DF increased progressively during the paroxysmal-to-persistent AF transition and stabilized when AF became persistent. Importantly, the rate of DF increase correlated strongly with the time to persistent AF. Significant action potential duration abbreviation, secondary to functional ion channel protein expression changes (CaV1.2, NaV1.5, and KV4.2 decrease; Kir2.3 increase), was already present at the transition and persisted for 1 year of follow up. CONCLUSIONS In the sheep model of long-standing persistent AF, the rate of DF increase predicts the time at which AF stabilizes and becomes persistent, reflecting changes in action potential duration and densities of sodium, L-type calcium, and inward rectifier currents.
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Affiliation(s)
- Raphael P Martins
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI (R.P.M., K.K., E.H., R.J.R., B.C.W., D.F.-R., S.R.E., Y.T., D.P.-B., M.Z., R.P.O., H.M., G.G.-S., U.M.R.A., S.V.P., O.B., J.J.); Department of Surgery, University of Rochester, Rochester, NY (M.F.S.); and Department of Engineering, Norfolk State University, Norfolk, VA (S.B., M.D.)
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Abstract
Ion channels and transporters are expressed in every living cell, where they participate in controlling a plethora of biological processes and physiological functions, such as excitation of cells in response to stimulation, electrical activities of cells, excitation-contraction coupling, cellular osmolarity, and even cell growth and death. Alterations of ion channels/transporters can have profound impacts on the cellular physiology associated with these proteins. Expression of ion channels/transporters is tightly regulated and expression deregulation can trigger abnormal processes, leading to pathogenesis, the channelopathies. While transcription factors play a critical role in controlling the transcriptome of ion channels/transporters at the transcriptional level by acting on the 5'-flanking region of the genes, microribonucleic acids (miRNAs), a newly discovered class of regulators in the gene network, are also crucial for expression regulation at the posttranscriptional level through binding to the 3'untranslated region of the genes. These small noncoding RNAs fine tune expression of genes involved in a wide variety of cellular processes. Recent studies revealed the role of miRNAs in regulating expression of ion channels/transporters and the associated physiological functions. miRNAs can target ion channel genes to alter cardiac excitability (conduction, repolarization, and automaticity) and affect arrhythmogenic potential of heart. They can modulate circadian rhythm, pain threshold, neuroadaptation to alcohol, brain edema, etc., through targeting ion channel genes in the neuronal systems. miRNAs can also control cell growth and tumorigenesis by acting on the relevant ion channel genes. Future studies are expected to rapidly increase to unravel a new repertoire of ion channels/transporters for miRNA regulation.
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Affiliation(s)
- Zhiguo Wang
- Harbin Medical University, Harbin, Heilongjiang, People's Republic of China.
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33
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Musa H, Kaur K, O'Connell R, Klos M, Guerrero-Serna G, Avula UMR, Herron TJ, Kalifa J, Anumonwo JMB, Jalife J. Inhibition of platelet-derived growth factor-AB signaling prevents electromechanical remodeling of adult atrial myocytes that contact myofibroblasts. Heart Rhythm 2013; 10:1044-51. [PMID: 23499624 PMCID: PMC3692578 DOI: 10.1016/j.hrthm.2013.03.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Indexed: 02/08/2023]
Abstract
BACKGROUND Persistent atrial fibrillation (PAF) results in electromechanical and structural remodeling by mechanisms that are poorly understood. Myofibroblast proliferation and fibrosis are major sources of structural remodeling in PAF. Myofibroblasts also interact with atrial myocytes via direct physical contact and release of signaling molecules, which may contribute to remodeling. OBJECTIVE To determine whether myofibroblasts contribute to atrial myocyte electromechanical remodeling via direct physical contact and platelet-derived growth factor (PDGF) signaling. METHODS Myofibroblasts and myocytes from adult sheep atria were co-cultured for 24 hours. Alternatively adult sheep atrial myocytes were exposed to 1 ng/mL recombitant PDGF AB peptide for 24 hours. RESULTS Myocytes making contact with myofibroblasts demonstrated significant reduction (P ≤ .05) in peak L-type calcium current density, shortening of action potential duration (APD), and reduction in calcium transients. These effects were blocked by pretreatment with a PDGF-AB neutralizing anti-body. Heterocellular contact also severely disturbed the localization of the L-type calcium channel. Myocytes exposed to recombinant PDGF-AB peptide for 24 hours demonstrated reduced APD50, APD80 and Peak L-type calcium current. Pretreatment with a PDGF-AB neutralizing antibody prevented these effects. Finally, while control atrial myocytes did not respond in a 1:1 manner to pacing frequencies of 3 Hz or higher, atrial myocytes from hearts that were tachypaced for 2 months and normal myocytes treated with PDGF-AB for 24 hours could be paced up to 10 Hz. CONCLUSIONS In addition to leading to fibrosis, atrial myofibroblasts contribute to electromechanical remodeling of myocytes via direct physical contact and release of PDGF-AB, which may be a factor in PAF-induced remodeling.
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Affiliation(s)
- Hassan Musa
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan 48109, USA.
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34
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Cardiac ion channels and mechanisms for protection against atrial fibrillation. Rev Physiol Biochem Pharmacol 2013; 162:1-58. [PMID: 21987061 DOI: 10.1007/112_2011_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Atrial fibrillation (AF) is recognised as the most common sustained cardiac arrhythmia in clinical practice. Ongoing drug development is aiming at obtaining atrial specific effects in order to prevent pro-arrhythmic, devastating ventricular effects. In principle, this is possible due to a different ion channel composition in the atria and ventricles. The present text will review the aetiology of arrhythmias with focus on AF and include a description of cardiac ion channels. Channels that constitute potentially atria-selective targets will be described in details. Specific focus is addressed to the recent discovery that Ca(2+)-activated small conductance K(+) channels (SK channels) are important for the repolarisation of atrial action potentials. Finally, an overview of current pharmacological treatment of AF is included.
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35
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Atrial remodeling: New pathophysiological mechanism of atrial fibrillation. Med Hypotheses 2013; 80:53-6. [DOI: 10.1016/j.mehy.2012.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 10/18/2012] [Indexed: 11/17/2022]
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Laszlo R, Konior A, Bentz K, Eick C, Schreiner B, Schreieck J, Bosch RF. Atrial reverse remodeling: restitution of early tachycardia-induced alterations of atrial ion currents after termination of rapid atrial pacing in rabbits. Res Vet Sci 2012; 94:320-4. [PMID: 22939085 DOI: 10.1016/j.rvsc.2012.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 08/08/2012] [Accepted: 08/10/2012] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE Studies report on the reversal of electrophysiological parameters altered by atrial tachycardia after cessation of the latter. However, there is no data concerning reversal of tachycardia-induced alterations of ion currents. Reverse remodeling of atrial ion currents (I(Ca,L), I(to), I(sus)) was studied in our rabbit model of tachycardia-induced electrical remodeling. METHODS Three groups each with four animals were built. Rapid atrial pacing (600/min) for 5 days was applied in all groups. Thereafter, different time intervals (5, 10, 20 days) were awaited before the patch clamp experiments. RESULTS Similar to I(to) remodeling in our model, within 20 days after cessation of atrial tachycardia, time course of I(to) reverse remodeling was also U-shaped. In contrast, there was no significant recovery of I(Ca,L) which was initially reduced by rapid atrial pacing. CONCLUSION Relevance of a missing recovery of I(Ca,L) is likely as this current is closely linked with intracellular calcium handling.
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Affiliation(s)
- Roman Laszlo
- Department of Cardiology, University of Tuebingen, Otfried-Mueller-Strasse 10, D-72076 Tuebingen, Germany.
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Cliff B, Younis N, Hama S, Soran H. The role of the renin-angiotensin system blocking in the management of atrial fibrillation. J Drug Assess 2012; 1:55-64. [PMID: 27536429 PMCID: PMC4980732 DOI: 10.3109/21556660.2012.672353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2012] [Indexed: 12/02/2022] Open
Abstract
OBJECTIVE To review current available evidence for the role of renin-angiotensin system blockade in the management of atrial fibrillation. METHOD We conducted a PubMed and Medline literature search (January 1980 through July 2011) to identify all clinical trials published in English concerning the use of angiotensin converting enzyme inhibitors or angiotensin II receptor blockers for primary and secondary prevention of atrial fibrillation. We also discussed renin-angiotensin system and its effects on cellular electrophysiology. CONCLUSION The evidence from the current studies discussed does not provide a firm definitive indication for the use of angiotensin converting enzyme inhibitors or angiotensin II receptor blockers in the primary or secondary prevention of atrial fibrillation. Nevertheless, modest benefits were observed in patients with left ventricular dysfunction. In view of the possible benefits and the low incidence of side-effects with angiotensin converting enzyme inhibitors and angiotensin II receptor blockers, they can be given to patients with recurrent AF, specifically those with hypertension, heart failure and diabetes mellitus.
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Affiliation(s)
- Brett Cliff
- University Department of Medicine, Central Manchester University Hospitals NHS Foundation Trust, ManchesterUK
| | - Naveed Younis
- Department of Diabetes and Endocrinology, South Manchester University Hospitals NHS Foundation Trust, ManchesterUK
| | - Salam Hama
- Cardiovascular Research Group, School of Biomedicine, Core Technology Facility (3rd Floor), University of Manchester, ManchesterUK
| | - Handrean Soran
- University Department of Medicine, Central Manchester University Hospitals, ManchesterUK
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Voigt N, Nattel S, Dobrev D. Proarrhythmic atrial calcium cycling in the diseased heart. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1175-91. [PMID: 22453988 DOI: 10.1007/978-94-007-2888-2_53] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
During the last decades Ca(2+) has been found to play a crucial role in cardiac arrhythmias associated with heart failure and a number of congenital arrhythmia syndromes. Recent studies demonstrated that altered atrial Ca(2+) cycling may promote the initiation and maintenance of atrial fibrillation, the most common clinical arrhythmia that contributes significantly to population morbidity and mortality. This article describes physiological Ca(2+) cycling mechanisms in atrial cardiomyocytes and relates them to fundamental cellular proarrhythmic mechanisms involving Ca(2+) signaling abnormalities in the atrium during atrial fibrillation.
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Affiliation(s)
- Niels Voigt
- Division of Experimental Cardiology, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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Sharma D, Li G, Xu G, Liu Y, Xu Y. Atrial remodeling in atrial fibrillation and some related microRNAs. Cardiology 2011; 120:111-21. [PMID: 22179059 DOI: 10.1159/000334434] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/12/2011] [Indexed: 01/17/2023]
Abstract
Atrial fibrillation is the most common sustained arrhythmia associated with substantial cardiovascular morbidity and mortality, with stroke being the most critical complication. The role of atrial remodeling has emerged as the new pathophysiological mechanism of atrial fibrillation. Electrical remodeling and structural remodeling will increase the probability of generating multiple atrial wavelets by enabling rapid atrial activation and dispersion of refractoriness. MicroRNAs (miRNAs) are small non-coding RNAs of 20-25 nucleotides in length that regulate expression of target genes through sequence-specific hybridization to the 3' untranslated region of messenger RNAs and either block translation or direct degradation of their target messenger RNA. They have also been implicated in a variety of pathological conditions, such as arrhythmogenesis and atrial fibrillation. Target genes of miRNAs have the potential to affect atrial fibrillation vulnerability.
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Affiliation(s)
- Deepak Sharma
- International College of Tianjin Medical University, Tianjin, China
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Yu J, Li W, Li Y, Zhao J, Wang L, Dong D, Pan Z, Yang B. Activation of β(3)-adrenoceptor promotes rapid pacing-induced atrial electrical remodeling in rabbits. Cell Physiol Biochem 2011; 28:87-96. [PMID: 21865851 DOI: 10.1159/000331717] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2011] [Indexed: 01/24/2023] Open
Abstract
Cardiac electrophysiological function is under the regulatory control of the sympathetic nervous system. In addition to classical β-adrenoceptors (β-AR, including β(1)- and β(2)- subtypes), β(3)-AR is also expressed in human heart and shows its distinctive functions. This study is aimed to elucidate the role of β(3)-AR in the regulation of atrial fibrillation (AF), especially its role in rapid pacing-induced atrial electrical remodeling in rabbits. The rapid atrial pacing model was established by embedding electrodes in the right atrium pacing at a speed of 600 beats per minute. The protein level of β(3)-AR in the atria was found significantly upregulated by western blot. The atrial effective refractory period (AERP) and its rate adaptation were decreased after pacing which were further shortened by BRL37344, a selective β(3)-AR agonist, leading to the increase of AF inducibility and duration. Similarly, β(3)-AR activation induced time-dependent shortening of action potential duration (APD), together with decrease of L-type calcium current (I(Ca,L)) and increase of inward rectifier potassium current (I(K1)) and transient outward potassium current (I(to)) in rapid pacing atrial myocytes. Meanwhile, all the effects were abolished by specific β(3)-AR antagonist, SR59230A. In summary, our study represents that activation of β(3)-AR promotes the atrial electrical remodeling process by altering the balance of ion channels in atrial myocytes, which provides new insights into the pharmacological role of β(3)-AR in heart diseases.
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Affiliation(s)
- Jiahui Yu
- Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin, RP China
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Xiao P, Gao C, Fan J, Du H, Long Y, Yin Y. Blockade of angiotensin II improves hyperthyroid induced abnormal atrial electrophysiological properties. ACTA ACUST UNITED AC 2011; 169:31-8. [DOI: 10.1016/j.regpep.2011.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 03/21/2011] [Accepted: 04/16/2011] [Indexed: 11/30/2022]
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Wakili R, Voigt N, Kääb S, Dobrev D, Nattel S. Recent advances in the molecular pathophysiology of atrial fibrillation. J Clin Invest 2011; 121:2955-68. [PMID: 21804195 DOI: 10.1172/jci46315] [Citation(s) in RCA: 427] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is an extremely common cardiac rhythm disorder that causes substantial morbidity and contributes to mortality. The mechanisms underlying AF are complex, involving both increased spontaneous ectopic firing of atrial cells and impulse reentry through atrial tissue. Over the past ten years, there has been enormous progress in understanding the underlying molecular pathobiology. This article reviews the basic mechanisms and molecular processes causing AF. We discuss the ways in which cardiac disease states, extracardiac factors, and abnormal genetic control lead to the arrhythmia. We conclude with a discussion of the potential therapeutic implications that might arise from an improved mechanistic understanding.
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Affiliation(s)
- Reza Wakili
- Research Center, Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
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YANG DONGHUI, XI YUTAO, AI TOMOHIKO, WU GERU, SUN JUNPING, RAZAVI MEHDI, DELAPASSE SCOTT, SHURAIL MOSSAIB, GAO LIANJUN, MATHURIA NILESH, ELAYDA MACARTHUR, CHENG JIE. Vagal Stimulation Promotes Atrial Electrical Remodeling Induced by Rapid Atrial Pacing in Dogs: Evidence of a Noncholinergic Effect. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2011; 34:1092-9. [DOI: 10.1111/j.1540-8159.2011.03133.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Schotten U, Verheule S, Kirchhof P, Goette A. Pathophysiological mechanisms of atrial fibrillation: a translational appraisal. Physiol Rev 2011; 91:265-325. [PMID: 21248168 DOI: 10.1152/physrev.00031.2009] [Citation(s) in RCA: 863] [Impact Index Per Article: 66.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia that can occur as the result of numerous different pathophysiological processes in the atria. Some aspects of the morphological and electrophysiological alterations promoting AF have been studied extensively in animal models. Atrial tachycardia or AF itself shortens atrial refractoriness and causes loss of atrial contractility. Aging, neurohumoral activation, and chronic atrial stretch due to structural heart disease activate a variety of signaling pathways leading to histological changes in the atria including myocyte hypertrophy, fibroblast proliferation, and complex alterations of the extracellular matrix including tissue fibrosis. These changes in electrical, contractile, and structural properties of the atria have been called "atrial remodeling." The resulting electrophysiological substrate is characterized by shortening of atrial refractoriness and reentrant wavelength or by local conduction heterogeneities caused by disruption of electrical interconnections between muscle bundles. Under these conditions, ectopic activity originating from the pulmonary veins or other sites is more likely to occur and to trigger longer episodes of AF. Many of these alterations also occur in patients with or at risk for AF, although the direct demonstration of these mechanisms is sometimes challenging. The diversity of etiological factors and electrophysiological mechanisms promoting AF in humans hampers the development of more effective therapy of AF. This review aims to give a translational overview on the biological basis of atrial remodeling and the proarrhythmic mechanisms involved in the fibrillation process. We pay attention to translation of pathophysiological insights gained from in vitro experiments and animal models to patients. Also, suggestions for future research objectives and therapeutical implications are discussed.
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Affiliation(s)
- Ulrich Schotten
- Department of Physiology, University Maastricht, Maastricht, The Netherlands.
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Abstract
Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia associated with pronounced morbidity, mortality, and socio-economic burden. This pathological entity is associated with an altered expression profile of genes that are important for atrial function. MicroRNAs (miRNAs), a new class of non-coding mRNAs of around 22 nucleotides in length, have rapidly emerged as one of the key players in the gene expression regulatory network. The potential roles of miRNAs in controlling AF have recently been investigated. The studies have provided some promising results for our better understanding of the molecular mechanisms of AF. In this review article, we provide a synopsis of the studies linking miRNAs to cardiac excitability and other processes pertinent to AF. To introduce the main topic, we discuss basic knowledge about miRNA biology and our current understanding of mechanisms for AF. The most up-to-date research data on the possible roles of miRNAs in AF initiation and maintenance are presented, and the available experimental results on miRNA and AF are discussed. Some speculations pertinent to the subject are made. Finally, perspectives on future directions of research on miRNAs in AF are provided.
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Affiliation(s)
- Zhiguo Wang
- Research Center, Montreal Heart Institute, 5000 Belanger East, Montreal, Canada PQ H1T 1C8.
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47
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Ravens U. Antiarrhythmic therapy in atrial fibrillation. Pharmacol Ther 2010; 128:129-45. [DOI: 10.1016/j.pharmthera.2010.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 12/19/2022]
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Atorvastatin treatment affects atrial ion currents and their tachycardia-induced remodeling in rabbits. Life Sci 2010; 87:507-13. [PMID: 20851131 DOI: 10.1016/j.lfs.2010.09.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 08/21/2010] [Accepted: 09/11/2010] [Indexed: 11/23/2022]
Abstract
AIMS Atrial fibrillation (AF) leads to electrical atrial remodeling including alterations of various ion channels early after arrhythmia onset. The beneficial effects of statins in AF treatment due to their influence on oxidative stress and inflammation are discussed. Our hypothesis was that statins might also alter atrial ion currents and their early tachycardia-induced remodeling. MAIN METHODS Effects of an atorvastatin treatment (7 days) on atrial ion currents and their tachycardia-induced alterations were studied in a rabbit model of tachycardia-induced electrical remodeling (rapid atrial pacing (600 min) for 24 and 120 h). Ion currents (L-type calcium channel [I(Ca,L)], transient outward current [I(to)]) were measured using whole cell patch clamp method and were compared with previous experiments in untreated but also tachypaced animals. KEY FINDINGS Atorvastatin treatment alone decreased I(Ca,L) similar to rapid atrial pacing alone, currents were also further reduced by additional atrial tachypacing. I(to) and its pacing-induced down-regulation after 24 h were not influenced by atorvastatin treatment. However, I(to) was still reduced after 120 h in atorvastatin-treated animals and did not return to control values as expected. SIGNIFICANCE The present study establishes that an atorvastatin treatment can affect atrial ion currents and their tachycardia-induced remodeling in a rabbit model. These results show that-amongst other positive effects on oxidative stress and inflammation-the impact of statins on ion currents and their tachycardia-induced alterations might also play a role in "upstream" treatment of AF with HMG-CoA reductase inhibitors.
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Laszlo R, Bentz K, Konior A, Eick C, Schreiner B, Kettering K, Schreieck J. Effects of selective mineralocorticoid receptor antagonism on atrial ion currents and early ionic tachycardia-induced electrical remodelling in rabbits. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:347-56. [PMID: 20799026 DOI: 10.1007/s00210-010-0553-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/12/2010] [Indexed: 12/19/2022]
Abstract
Over the past years, the importance of the renin-angiotensin-aldosterone system in atrial fibrillation (AF) pathophysiology has been recognised. Lately, the role of aldosterone in AF pathophysiology and mineralocorticoid receptor (MR) antagonism in "upstream" AF treatment is discussed. Hypothesising that selective MR antagonism might also influence atrial ion currents (L-type calcium current [I (Ca,L)], transient outward potassium current [I (to)], sustained outward potassium current [I (sus)]) and their tachycardia-induced remodelling, the effects of an eplerenone treatment were studied in a rabbit model. Six groups each with four animals were built. Animals of the control group received atrial pacing leads, but in contrast to the pacing groups, no atrial tachypacing (600 per minute for 24 and 120 h immediately before heart removal) was applied. Animals of the eplerenone groups were instrumented/paced as the corresponding control/pacing groups, but were additionally treated with eplerenone (7 days before heart removal). Atrial tachypacing was associated with a reduction of I (Ca,L). I (to) was decreased after 24 h of tachypacing, but returned to control values after 120 h. In the absence of rapid atrial pacing, MR antagonism reduced I (Ca,L) to a similar extent as 120 h of tachypacing alone. Based on this lower "take-off level", I (Ca,L) was not further decreased by high-rate pacing. I (to) and its expected tachycardia-induced alterations were not influenced by MR antagonism. In our experiments, selective MR antagonism influenced atrial I (Ca,L) and its tachycardia-induced alterations. As changes of I (Ca,L) are closely linked with atrial calcium signalling, the relevance of these alterations in AF pathophysiology and, accordingly, AF treatment is likely and has to be further evaluated.
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Affiliation(s)
- Roman Laszlo
- Kardiologie und Kreislauferkrankungen, Eberhard Karls Universität Tuebingen, Otfried-Mueller-Straße 10, 72076, Tuebingen, Germany.
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50
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Wakili R, Yeh YH, Yan Qi X, Greiser M, Chartier D, Nishida K, Maguy A, Villeneuve LR, Boknik P, Voigt N, Krysiak J, Kääb S, Ravens U, Linke WA, Stienen GJM, Shi Y, Tardif JC, Schotten U, Dobrev D, Nattel S. Multiple potential molecular contributors to atrial hypocontractility caused by atrial tachycardia remodeling in dogs. Circ Arrhythm Electrophysiol 2010; 3:530-41. [PMID: 20660541 DOI: 10.1161/circep.109.933036] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Atrial fibrillation impairs atrial contractility, inducing atrial stunning that promotes thromboembolic stroke. Action potential (AP)-prolonging drugs are reported to normalize atrial hypocontractility caused by atrial tachycardia remodeling (ATR). Here, we addressed the role of AP duration (APD) changes in ATR-induced hypocontractility. METHODS AND RESULTS ATR (7-day tachypacing) decreased APD (perforated patch recording) by ≈50%, atrial contractility (echocardiography, cardiomyocyte video edge detection), and [Ca(2+)](i) transients. ATR AP waveforms suppressed [Ca(2+)](i) transients and cell shortening of control cardiomyocytes; whereas control AP waveforms improved [Ca(2+)](i) transients and cell shortening in ATR cells. However, ATR cardiomyocytes clamped with the same control AP waveform had ≈60% smaller [Ca(2+)](i) transients and cell shortening than control cells. We therefore sought additional mechanisms of contractile impairment. Whole-cell voltage clamp revealed reduced I(CaL); I(CaL) inhibition superimposed on ATR APs further suppressed [Ca(2+)](i) transients in control cells. Confocal microscopy indicated ATR-impaired propagation of the Ca(2+) release signal to the cell center in association with loss of t-tubular structures. Myofilament function studies in skinned permeabilized cardiomyocytes showed altered Ca(2+) sensitivity and force redevelopment in ATR, possibly due to hypophosphorylation of myosin-binding protein C and myosin light-chain protein 2a (immunoblot). Hypophosphorylation was related to multiple phosphorylation system abnormalities where protein kinase A regulatory subunits were downregulated, whereas autophosphorylation and expression of Ca(2+)-calmodulin-dependent protein kinase IIδ and protein phosphatase 1 activity were enhanced. Recovery of [Ca(2+)](i) transients and cell shortening occurred in parallel after ATR cessation. CONCLUSIONS Shortening of APD contributes to hypocontractility induced by 1-week ATR but accounts for it only partially. Additional contractility-suppressing mechanisms include I(CaL) current reduction, impaired subcellular Ca(2+) signal transmission, and altered myofilament function associated with abnormal myosin and myosin-associated protein phosphorylation. The complex mechanistic basis of the atrial hypocontractility associated with AF argues for upstream therapeutic targeting rather than interventions directed toward specific downstream pathophysiological derangements.
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Affiliation(s)
- Reza Wakili
- Department of Medicine and Research Center, Université de Montréal, Montreal, Quebec, Canada
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