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Kambayashi R, Goto A, Shinozaki M, Izumi-Nakaseko H, Takei Y, Iwata K, Kaneko N, Sugiyama A. In vivo cardiovascular profile of ryanodine receptor 2 inhibitor M201-A: Utility as an anti-atrial fibrillatory drug for patients suffering from heart failure with preserved ejection fraction. J Pharmacol Sci 2024; 156:171-179. [PMID: 39313275 DOI: 10.1016/j.jphs.2024.08.004] [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: 05/11/2024] [Revised: 07/17/2024] [Accepted: 08/20/2024] [Indexed: 09/25/2024] Open
Abstract
Atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) often coexist; however, clinically available anti-AF drugs can exacerbate symptoms of HFpEF. M201-A suppressed ryanodine receptor-mediated diastolic Ca2+ leakage, possibly inhibiting common pathological processes toward AF and HFpEF. To bridge the basic information to clinical practice, we assessed its cardiohemodynamic, anti-AF and ventricular proarrhythmic profile using halothane-anesthetized dogs (n = 4). M201-A hydrochloride in doses of 0.03, 0.3 and 3 mg/kg/10 min was intravenously administered, providing peak plasma concentrations of 0.09, 0.81 and 5.70 μg/mL, respectively. The high dose of M201-A showed various cardiovascular actions. Namely, M201-A increased mean blood pressure and tended to enhance isovolumetric ventricular relaxation without suppressing ventricular contraction or decreasing cardiac output. M201-A enhanced atrioventricular conduction, but hardy affected intra-atrial/ventricular conduction. Importantly, M201-A prolonged effective refractory period more potently in the atrium than in the ventricle, indicating that it may become an atrial-selective antiarrhythmic drug. Meanwhile, M201-A prolonged QT interval/QTcV, and showed reverse frequency-dependent delay of ventricular repolarization. M201-A prolonged J-Tpeakc without prolonging Tpeak-Tend or terminal repolarization period, indicating the risk of causing torsade de pointes is negligible. Thus, M201-A is expected to become a hopeful therapeutic strategy for patients having pathology of both AF and HFpEF.
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Affiliation(s)
- Ryuichi Kambayashi
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Ai Goto
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Makoto Shinozaki
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan; Aetas Pharma Co., Ltd, 1-7 Kanda-Ogawamachi, Chiyoda-ku, Tokyo, 101-0052, Japan
| | - Hiroko Izumi-Nakaseko
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Yoshinori Takei
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan; Kazuya Yokoyama Cancer Research Institute, 1-4-8 Ueno, Taito-ku, Tokyo, 110-0005, Japan
| | - Kunio Iwata
- Aetas Pharma Co., Ltd, 1-7 Kanda-Ogawamachi, Chiyoda-ku, Tokyo, 101-0052, Japan
| | - Noboru Kaneko
- Aetas Pharma Co., Ltd, 1-7 Kanda-Ogawamachi, Chiyoda-ku, Tokyo, 101-0052, Japan; Department of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi, 321-0293, Japan
| | - Atsushi Sugiyama
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan; Kazuya Yokoyama Cancer Research Institute, 1-4-8 Ueno, Taito-ku, Tokyo, 110-0005, Japan.
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Kaneko N, Loughrey CM, Smith G, Matsuda R, Hasunuma T, Mark PB, Toda M, Shinozaki M, Otani N, Kayley S, Da Silva Costa A, Martin TP, Dobi S, Saxena P, Shimamoto K, Ishikawa T, Kambayashi R, Riddell A, Elliott EB, McCarroll CS, Sakai T, Mitsuhisa Y, Hirano S, Kitai T, Kusano K, Inoue Y, Nakamura M, Kikuchi M, Toyoda S, Taguchi I, Fujiwara T, Sugiyama A, Kumagai Y, Iwata K. A novel ryanodine receptor 2 inhibitor, M201-A, enhances natriuresis, renal function and lusi-inotropic actions: Preclinical and phase I study. Br J Pharmacol 2024; 181:3401-3419. [PMID: 38773354 DOI: 10.1111/bph.16379] [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: 10/12/2023] [Revised: 02/17/2024] [Accepted: 02/20/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND AND PURPOSE The ryanodine receptor 2 (RyR2) is present in both the heart and kidneys, and plays a crucial role in maintaining intracellular Ca2+ homeostasis in cells in these organs. This study aimed to investigate the impact of M201-A on RyR2, as well as studying its effects on cardiac and renal functions in preclinical and clinical studies. EXPERIMENTAL APPROACH Following the administration of M201-A (1,4-benzothiazepine-1-oxide derivative), we monitored diastolic Ca2+ leak via RyR2 and intracellular Ca2+ concentration in isolated rat cardiomyocytes and in cardiac and renal function in animals. In a clinical study, M201-A was administered intravenously at doses of 0.2 and 0.4 mg·kg-1 once daily for 20 min for four consecutive days in healthy males, with the assessment of haemodynamic responses. KEY RESULTS In rat heart cells, M201-A effectively inhibited spontaneous diastolic Ca2+ leakage through RyR2 and exhibited positive lusi-inotropic effects on the rat heart. Additionally, it enhanced natriuresis and improved renal function in dogs. In human clinical studies, when administered intravenously, M201-A demonstrated an increase in natriuresis, glomerular filtration rate and creatinine clearance, while maintaining acceptable levels of drug safety and tolerability. CONCLUSIONS AND IMPLICATIONS The novel drug M201-A inhibited diastolic Ca2+ leak via RyR2, improved cardiac lusi-inotropic effects in rats, and enhanced natriuresis and renal function in humans. These findings suggest that this drug may offer a potential new treatment option for chronic kidney disease and heart failure.
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Affiliation(s)
- Noboru Kaneko
- Department of Medicine, Dokkyo Medical University, Tochigi, Japan
- AETAS Pharma Co., Ltd., Tokyo, Japan
| | | | - Godfrey Smith
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Ryuko Matsuda
- AETAS Pharma Co., Ltd., Tokyo, Japan
- Nojima Hospital, Tottori, Japan
| | | | - Patric B Mark
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | | | | | - Naoyuki Otani
- Dokkyo Medical University Nikko Medical Center, Tochigi, Japan
| | - Scott Kayley
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Ana Da Silva Costa
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Tamara P Martin
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Sara Dobi
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Priyanka Saxena
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Ken Shimamoto
- Division of Cardiovascular Medicine, Sendai Cardiovascular Center, Miyagi, Japan
| | - Tetsuya Ishikawa
- Department of Cardiology, Dokkyo Medical University, Saitama Medical Center, Saitama, Japan
| | - Ryuichi Kambayashi
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Alexandra Riddell
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Elspeth B Elliott
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | | | | | | | - Sayuri Hirano
- Process Research & Development Laboratories Technology Research & Development Division, Sumitomo Dainippon Pharma Co. Ltd., Osaka, Japan
| | - Takeshi Kitai
- Department of Heart Failure and Transplantation, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Kengo Kusano
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Yuko Inoue
- Department of Heart Failure and Transplantation, National Cerebral and Cardiovascular Center, Osaka, Japan
| | | | - Migaku Kikuchi
- Department of Cardiovascular Medicine, Dokkyo Medical University, Tochigi, Japan
| | - Shigeru Toyoda
- Department of Cardiovascular Medicine, Dokkyo Medical University, Tochigi, Japan
| | - Isao Taguchi
- Department of Cardiology, Dokkyo Medical University, Saitama Medical Center, Saitama, Japan
| | | | - Atsushi Sugiyama
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan
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Dobrev D, Heijman J, Hiram R, Li N, Nattel S. Inflammatory signalling in atrial cardiomyocytes: a novel unifying principle in atrial fibrillation pathophysiology. Nat Rev Cardiol 2023; 20:145-167. [PMID: 36109633 PMCID: PMC9477170 DOI: 10.1038/s41569-022-00759-w] [Citation(s) in RCA: 79] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/26/2022] [Indexed: 02/08/2023]
Abstract
Inflammation has been implicated in atrial fibrillation (AF), a very common and clinically significant cardiac rhythm disturbance, but its precise role remains poorly understood. Work performed over the past 5 years suggests that atrial cardiomyocytes have inflammatory signalling machinery - in particular, components of the NLRP3 (NACHT-, LRR- and pyrin domain-containing 3) inflammasome - that is activated in animal models and patients with AF. Furthermore, work in animal models suggests that NLRP3 inflammasome activation in atrial cardiomyocytes might be a sufficient and necessary condition for AF occurrence. In this Review, we evaluate the evidence for the role and pathophysiological significance of cardiomyocyte NLRP3 signalling in AF. We first summarize the evidence for a role of inflammation in AF and review the biochemical properties of the NLRP3 inflammasome, as defined primarily in studies of classic inflammation. We then briefly consider the broader evidence for a role of inflammatory signalling in heart disease, particularly conditions that predispose individuals to develop AF. We provide a detailed discussion of the available information about atrial cardiomyocyte NLRP3 inflammasome signalling in AF and related conditions and evaluate the possibility that similar signalling might be important in non-myocyte cardiac cells. We then review the evidence on the role of active resolution of inflammation and its potential importance in suppressing AF-related inflammatory signalling. Finally, we consider the therapeutic potential and broader implications of this new knowledge and highlight crucial questions to be addressed in future research.
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Affiliation(s)
- Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Duisburg, Germany
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, Canada
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Roddy Hiram
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, Canada
| | - Na Li
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine, Section of Cardiovascular Research, Baylor College of Medicine, Houston, TX, USA
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Stanley Nattel
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Duisburg, Germany.
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, Canada.
- IHU LIRYC and Fondation Bordeaux Université, Bordeaux, France.
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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Systematic review of pre-clinical therapies for post-operative atrial fibrillation. PLoS One 2020; 15:e0241643. [PMID: 33147274 PMCID: PMC7641461 DOI: 10.1371/journal.pone.0241643] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 10/16/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Post-operative atrial fibrillation (POAF) is a frequent cardiothoracic surgery complication that increases hospital stay, mortality and costs. Despite decades of research, there has been no systematic overview and meta-analysis of preclinical therapies for POAF in animal models. METHODS We performed a systematic search of MEDLINE and EMBASE from their inception through September 2020 to determine the effect of preclinical POAF therapies on primary efficacy outcomes using a prospectively registered protocol (CRD42019155649). Bias was assessed using the SYRCLE tool and CAMARADES checklist. RESULTS Within the 26 studies that fulfilled our inclusion criteria, we identified 4 prevention strategies including biological (n = 5), dietary (n = 2), substrate modification (n = 2), and pharmacological (n = 17) interventions targeting atrial substrate, cellular electrophysiology or inflammation. Only one study altered more than 1 pathophysiological mechanism. 73% comprised multiple doses of systemic therapies. Large animal models were used in 81% of the studies. Preclinical therapies altogether attenuated atrial fibrosis (SMD -2.09; 95% confidence interval [CI] -2.95 to -1.22; p < 0.00001; I2 = 47%), AF inducibility (RR 0.40; 95% CI 0.21 to 0.79; p = 0.008; I2 = 39%), and AF duration (SMD -2.19; 95% CI -3.05 to -1.32; p < 0.00001; I2 = 50%). However, all the criteria needed to evaluate the risk of bias was unclear for many outcomes and only few interventions were independently validated by more than 1 research group. CONCLUSION Treatments with therapies targeting atrial substrate, cellular electrophysiology or inflammation reduced POAF in preclinical animal models compared to controls. Improving the quality of outcome reporting, independently validating promising approaches and targeting complimentary drivers of POAF are promising means to improve the clinical translation of novel therapies for this highly prevalent and clinically meaningful disease.
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Wong CK, Tse HF. New methodological approaches to atrial fibrillation drug discovery. Expert Opin Drug Discov 2020; 16:319-329. [PMID: 33016154 DOI: 10.1080/17460441.2021.1826432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and rhythm control using pharmacological agents is required in selected patients. Nonetheless, current medication is only modestly efficacious and associated with significant cardiovascular and systemic side effects. More efficacious and safe drugs are required to restore and maintain sinus rhythm in patients with AF. AREAS COVERED In this review, several potential drug targets are discussed including trans-membrane ion channels, intracellular calcium signaling, gap junction signaling, atrial inflammation and fibrosis, and the autonomic nervous system. New tools and methodologies for AF drug development are also reviewed including gene therapy, genome-guided therapy, stem cell technologies, tissue engineering, and optogenetics. EXPERT OPINION In recent decades, there has been an increased understanding of the underlying pathogenesis of AF. As a result, there is a gradual paradigm shift from focusing only on trans-membrane ion channel inhibition to developing therapeutic agents that target other underlying arrhythmogenic mechanisms. Gene therapy and genome-guided therapy are emerging as novel treatments for AF with some success in proof-of-concept studies. Recent advances in stem cell technology, tissue engineering, and optogenetics may allow more effective in-vitro drug screening than conventional methodologies.
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Affiliation(s)
- Chun-Ka Wong
- Cardiology Division, Department of Medicine, The University of Hong Kong, Hong Kong, SAR China
| | - Hung-Fat Tse
- Cardiology Division, Department of Medicine, The University of Hong Kong, Hong Kong, SAR China
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Njegic A, Wilson C, Cartwright EJ. Targeting Ca 2 + Handling Proteins for the Treatment of Heart Failure and Arrhythmias. Front Physiol 2020; 11:1068. [PMID: 33013458 PMCID: PMC7498719 DOI: 10.3389/fphys.2020.01068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/04/2020] [Indexed: 12/18/2022] Open
Abstract
Diseases of the heart, such as heart failure and cardiac arrhythmias, are a growing socio-economic burden. Calcium (Ca2+) dysregulation is key hallmark of the failing myocardium and has long been touted as a potential therapeutic target in the treatment of a variety of cardiovascular diseases (CVD). In the heart, Ca2+ is essential for maintaining normal cardiac function through the generation of the cardiac action potential and its involvement in excitation contraction coupling. As such, the proteins which regulate Ca2+ cycling and signaling play a vital role in maintaining Ca2+ homeostasis. Changes to the expression levels and function of Ca2+-channels, pumps and associated intracellular handling proteins contribute to altered Ca2+ homeostasis in CVD. The remodeling of Ca2+-handling proteins therefore results in impaired Ca2+ cycling, Ca2+ leak from the sarcoplasmic reticulum and reduced Ca2+ clearance, all of which contributes to increased intracellular Ca2+. Currently, approved treatments for targeting Ca2+ handling dysfunction in CVD are focused on Ca2+ channel blockers. However, whilst Ca2+ channel blockers have been successful in the treatment of some arrhythmic disorders, they are not universally prescribed to heart failure patients owing to their ability to depress cardiac function. Despite the progress in CVD treatments, there remains a clear need for novel therapeutic approaches which are able to reverse pathophysiology associated with heart failure and arrhythmias. Given that heart failure and cardiac arrhythmias are closely associated with altered Ca2+ homeostasis, this review will address the molecular changes to proteins associated with both Ca2+-handling and -signaling; their potential as novel therapeutic targets will be discussed in the context of pre-clinical and, where available, clinical data.
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Affiliation(s)
- Alexandra Njegic
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom.,Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Claire Wilson
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom.,Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom
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Lemme M, Braren I, Prondzynski M, Aksehirlioglu B, Ulmer BM, Schulze ML, Ismaili D, Meyer C, Hansen A, Christ T, Lemoine MD, Eschenhagen T. Chronic intermittent tachypacing by an optogenetic approach induces arrhythmia vulnerability in human engineered heart tissue. Cardiovasc Res 2020; 116:1487-1499. [PMID: 31598634 PMCID: PMC7314638 DOI: 10.1093/cvr/cvz245] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 07/31/2019] [Accepted: 10/04/2019] [Indexed: 01/01/2023] Open
Abstract
AIMS Chronic tachypacing is commonly used in animals to induce cardiac dysfunction and to study mechanisms of heart failure and arrhythmogenesis. Human induced pluripotent stem cells (hiPSC) may replace animal models to overcome species differences and ethical problems. Here, 3D engineered heart tissue (EHT) was used to investigate the effect of chronic tachypacing on hiPSC-cardiomyocytes (hiPSC-CMs). METHODS AND RESULTS To avoid cell toxicity by electrical pacing, we developed an optogenetic approach. EHTs were transduced with lentivirus expressing channelrhodopsin-2 (H134R) and stimulated by 15 s bursts of blue light pulses (0.3 mW/mm2, 30 ms, 3 Hz) separated by 15 s without pacing for 3 weeks. Chronic optical tachypacing did not affect contractile peak force, but induced faster contraction kinetics, shorter action potentials, and shorter effective refractory periods. This electrical remodelling increased vulnerability to tachycardia episodes upon electrical burst pacing. Lower calsequestrin 2 protein levels, faster diastolic depolarization (DD) and efficacy of JTV-519 (46% at 1 µmol/L) to terminate tachycardia indicate alterations of Ca2+ handling being part of the underlying mechanism. However, other antiarrhythmic compounds like flecainide (69% at 1 µmol/L) and E-4031 (100% at 1 µmol/L) were also effective, but not ivabradine (1 µmol/L) or SEA0400 (10 µmol/L). CONCLUSION We demonstrated a high vulnerability to tachycardia of optically tachypaced hiPSC-CMs in EHT and the effective termination by ryanodine receptor stabilization, sodium or hERG potassium channel inhibition. This new model might serve as a preclinical tool to test antiarrhythmic drugs increasing the insight in treating ventricular tachycardia.
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Affiliation(s)
- Marta Lemme
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Ingke Braren
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Maksymilian Prondzynski
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Bülent Aksehirlioglu
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Bärbel M Ulmer
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Mirja L Schulze
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Djemail Ismaili
- Department of Cardiology-Electrophysiology, University Heart Center, 20246 Hamburg, Germany
| | - Christian Meyer
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
- Department of Cardiology-Electrophysiology, University Heart Center, 20246 Hamburg, Germany
| | - Arne Hansen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Marc D Lemoine
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
- Department of Cardiology-Electrophysiology, University Heart Center, 20246 Hamburg, Germany
| | - Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
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Dobrev D, Wehrens XHT. Calcium-mediated cellular triggered activity in atrial fibrillation. J Physiol 2017; 595:4001-4008. [PMID: 28181690 DOI: 10.1113/jp273048] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 01/25/2017] [Indexed: 12/29/2022] Open
Abstract
Although atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia, the basic mechanisms underlying this disorder remain incompletely understood. During the past decade or so, it has become clear that alterations in intracellular Ca2+ handling may play a role in the pathogenesis of AF. Studies in small and large animal models, as well as atrial samples from patients with different forms of AF, have implicated ryanodine receptor type 2 (RyR2) dysfunction and enhanced spontaneous Ca2+ release events from the sarcoplasmic reticulum (SR) as a potential cause of proarrhythmic cellular ectopic (triggered) activity in AF. The molecular mechanisms leading to RyR2 dysfunction and SR Ca2+ leak depend on the clinical stage of AF or specific animal model studied. This review focuses on the mechanisms and role of calcium-mediated cellular triggered activity in AF, and addresses some of the current controversies in the field.
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Affiliation(s)
- Dobromir Dobrev
- Institute for Pharmacology, West German Heart and Vascular Centre, University Duisburg-Essen, Essen, Germany.,Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Departments of Molecular Physiology & Biophysics, Pediatrics (Cardiology), Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA
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del Canto I, Such-Miquel L, Brines L, Soler C, Zarzoso M, Calvo C, Parra G, Tormos Á, Alberola A, Millet J, Such L, Chorro FJ. Effects of JTV-519 on stretch-induced manifestations of mechanoelectric feedback. Clin Exp Pharmacol Physiol 2016; 43:1062-1070. [DOI: 10.1111/1440-1681.12630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 07/16/2016] [Accepted: 08/01/2016] [Indexed: 12/29/2022]
Affiliation(s)
- Irene del Canto
- Department of Medicine; Valencia University “Estudi General”; Valencia Spain
| | - Luis Such-Miquel
- Department of Physiotherapy; Valencia University “Estudi General”; Valencia Spain
| | - Laia Brines
- Department of Physiology; Valencia University “Estudi General”; Valencia Spain
| | - Carlos Soler
- Department of Physiology; Valencia University “Estudi General”; Valencia Spain
| | - Manuel Zarzoso
- Department of Physiotherapy; Valencia University “Estudi General”; Valencia Spain
| | - Conrado Calvo
- Department of Electronic Engineering; Valencia Polytechnic University; Valencia Spain
| | - Germán Parra
- Department of Physiology; Valencia University “Estudi General”; Valencia Spain
| | - Álvaro Tormos
- Department of Electronic Engineering; Valencia Polytechnic University; Valencia Spain
| | - Antonio Alberola
- Department of Physiology; Valencia University “Estudi General”; Valencia Spain
| | - José Millet
- Department of Electronic Engineering; Valencia Polytechnic University; Valencia Spain
| | - Luis Such
- Department of Physiology; Valencia University “Estudi General”; Valencia Spain
| | - Francisco J. Chorro
- Department of Medicine; Valencia University “Estudi General”; Valencia Spain
- Department of Cardiology; Valencia University Clinic Hospital; INCLIVA; Valencia Spain
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Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII) has emerged as key enzyme in many cardiac pathologies, especially heart failure (HF), myocardial infarction and cardiomyopathies, thus leading to contractile dysfunction and malignant arrhythmias. While many pathways leading to CaMKII activation have been elucidated in recent years, hardly any clinically viable compounds affecting CaMKII activity have progressed from basic in vitro science to in vivo studies. This review focuses on recent advances in anti-arrhythmic strategies involving CaMKII. Specifically, both inhibition of CaMKII itself to prevent arrhythmias, as well as anti-arrhythmic approaches affecting CaMKII activity via alterations in signaling cascades upstream and downstream of CaMKII will be discussed.
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Affiliation(s)
- Julian Mustroph
- Universitäres Herzzentrum Regensburg, Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
| | - Stefan Neef
- Universitäres Herzzentrum Regensburg, Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
| | - Lars S Maier
- Universitäres Herzzentrum Regensburg, Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany.
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Grandi E, Maleckar MM. Anti-arrhythmic strategies for atrial fibrillation: The role of computational modeling in discovery, development, and optimization. Pharmacol Ther 2016; 168:126-142. [PMID: 27612549 DOI: 10.1016/j.pharmthera.2016.09.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with increased risk of cerebrovascular stroke, and with several other pathologies, including heart failure. Current therapies for AF are targeted at reducing risk of stroke (anticoagulation) and tachycardia-induced cardiomyopathy (rate or rhythm control). Rate control, typically achieved by atrioventricular nodal blocking drugs, is often insufficient to alleviate symptoms. Rhythm control approaches include antiarrhythmic drugs, electrical cardioversion, and ablation strategies. Here, we offer several examples of how computational modeling can provide a quantitative framework for integrating multiscale data to: (a) gain insight into multiscale mechanisms of AF; (b) identify and test pharmacological and electrical therapy and interventions; and (c) support clinical decisions. We review how modeling approaches have evolved and contributed to the research pipeline and preclinical development and discuss future directions and challenges in the field.
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Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, USA.
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Voigt N, Heijman J, Dobrev D. New antiarrhythmic targets in atrial fibrillation. Future Cardiol 2015; 11:645-54. [PMID: 26609872 DOI: 10.2217/fca.15.67] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia in developed countries. AF is associated with increased mortality and morbidity due to thromboembolism, stroke and worsening of pre-existing heart failure. Currently available pharmacological therapies for AF suffer from unsatisfying efficacy and/or are associated with major side effects such as bleeding complications or proarrhythmia. These limitations largely result from the fact that most of the currently available drugs were developed on an empirical basis, without precise knowledge of the molecular mechanisms underlying the arrhythmia. During the last decade substantial progress has been made in understanding the molecular mechanisms contributing to the initiation and maintenance of AF. This knowledge is expected to stimulate the development of safer and more effective drugs. Here, we review new antiarrhythmic drug targets, which have emerged based on this increasing knowledge about the molecular mechanisms of AF.
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Affiliation(s)
- Niels Voigt
- Faculty of Medicine, Institute of Pharmacology, University Duisburg-Essen, Hufelandstr 55, 45122 Essen, Germany
| | - Jordi Heijman
- Faculty of Medicine, Institute of Pharmacology, University Duisburg-Essen, Hufelandstr 55, 45122 Essen, Germany
| | - Dobromir Dobrev
- Faculty of Medicine, Institute of Pharmacology, University Duisburg-Essen, Hufelandstr 55, 45122 Essen, Germany
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16
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Driessen HE, Bourgonje VJA, van Veen TAB, Vos MA. New antiarrhythmic targets to control intracellular calcium handling. Neth Heart J 2014; 22:198-213. [PMID: 24733689 PMCID: PMC4016334 DOI: 10.1007/s12471-014-0549-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sudden cardiac death due to ventricular arrhythmias is a major problem. Drug therapies to prevent SCD do not provide satisfying results, leading to the demand for new antiarrhythmic strategies. New targets include Ca2+/Calmodulin-dependent protein kinase II (CaMKII), the Na/Ca exchanger (NCX), the Ryanodine receptor (RyR, and its associated protein FKBP12.6 (Calstabin)) and the late component of the sodium current (INa-Late), all related to intracellular calcium (Ca2+) handling. In this review, drugs interfering with these targets (SEA-0400, K201, KN-93, W7, ranolazine, sophocarpine, and GS-967) are evaluated and their future as clinical compounds is considered. These new targets prove to be interesting; however more insight into long-term drug effects is necessary before clinical applicability becomes reality.
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Affiliation(s)
- H E Driessen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, the Netherlands,
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Woods CE, Olgin J. Atrial fibrillation therapy now and in the future: drugs, biologicals, and ablation. Circ Res 2014; 114:1532-46. [PMID: 24763469 PMCID: PMC4169264 DOI: 10.1161/circresaha.114.302362] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 03/03/2014] [Indexed: 01/26/2023]
Abstract
Atrial fibrillation (AF) is a complex disease with multiple inter-relating causes culminating in rapid, seemingly disorganized atrial activation. Therapy targeting AF is rapidly changing and improving. The purpose of this review is to summarize current state-of-the-art diagnostic and therapeutic modalities for treatment of AF. The review focuses on reviewing treatment as it relates to the pathophysiological basis of disease and reviews preclinical and clinical evidence for potential new diagnostic and therapeutic modalities, including imaging, biomarkers, pharmacological therapy, and ablative strategies for AF. Current ablation and drug therapy approaches to treating AF are largely based on treating the arrhythmia once the substrate occurs and is more effective in paroxysmal AF rather than persistent or permanent AF. However, there is much research aimed at prevention strategies, targeting AF substrate, so-called upstream therapy. Improved diagnostics, using imaging, genetics, and biomarkers, are needed to better identify subtypes of AF based on underlying substrate/mechanism to allow more directed therapeutic approaches. In addition, novel antiarrhythmics with more atrial specific effects may reduce limiting proarrhythmic side effects. Advances in ablation therapy are aimed at improving technology to reduce procedure time and in mechanism-targeted approaches.
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Affiliation(s)
- Christopher E Woods
- From the Division of Cardiology, University of California at San Francisco (C.E.W., J.O.); and Division of Cardiology Research, AUST Development, LLC, Mountain View, CA (C.E.W.)
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Heijman J, Voigt N, Dobrev D. New directions in antiarrhythmic drug therapy for atrial fibrillation. Future Cardiol 2013; 9:71-88. [DOI: 10.2217/fca.12.78] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia and has a significant impact on morbidity and mortality. Current antiarrhythmic drugs for AF suffer from limited safety and efficacy, probably because they were not designed based on specific pathological mechanisms. Recent research has provided important insights into the mechanisms contributing to AF and highlighted several potential novel antiarrhythmic strategies. In this review, we highlight the main pathological mechanisms of AF, discuss traditional and novel aspects of atrial antiarrhythmic drugs in relation to these pathological mechanisms, and present potential novel therapeutic approaches including structure-based modulation of atrial-specific cardiac ion channels, restoring abnormal Ca2+ handling in AF and targeting atrial remodeling.
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Affiliation(s)
- Jordi Heijman
- Institute of Pharmacology, Medical Faculty Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Niels Voigt
- Institute of Pharmacology, Medical Faculty Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
- Division of Experimental Cardiology, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Dobromir Dobrev
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
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Otani N, Matsuda R, Oda K, Nishino S, Inoue T, Kaneko N. Protective effect of K201 on isoproterenol-induced and ischemic-reperfusion-induced ventricular arrhythmias in the rat: comparison with diltiazem. J Cardiovasc Pharmacol Ther 2012; 18:184-90. [PMID: 23144205 DOI: 10.1177/1074248412465489] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AIM Ventricular arrhythmia (VA) is a risk for sudden death. Polymorphic ventricular tachycardia (VT) degenerating to ventricular fibrillation occurs subsequent to the prolongation of the QT interval following administration of catecholamines under Ca(2+) loading. Fatal VA also occurs in ischemia and ischemic-reperfusion. We compared the suppressive effect of K201 (JTV519), a multiple-channel blocker and cardiac ryanodine receptor-calcium release channel (RyR2) stabilizer, with that of diltiazem, a Ca(2+ )channel blocker, in 2 studies of isoproterenol-induced (n = 30) and ischemic-reperfusion-induced VAs (n = 38) in rats. METHODS Adult male Wistar rats were administered 12 mg/kg/min calcium chloride (CaCl(2)) for 20 minutes and then 6 μg/kg/min isoproterenol was infused with CaCl(2) for a further 20 minutes. In other rats, the left coronary artery was ligated for 5 minutes followed by reperfusion for 20 minutes. K201 or diltiazem (both 1 mg/kg) was administered before infusion of the isoproterenol or induction of ischemia. RESULTS After administration of isoproterenol under Ca(2+) loading, fatal VA frequently occurred in the vehicle (9 of 10 animals, 90%) and diltiazem (8 of 10, 80%) groups, and K201 significantly suppressed the incidences of arrhythmia and mortality (2 of 10, 20%). In the reperfusion study, the incidence and the time until occurrence of reperfusion-induced VA and mortality were significantly suppressed in the K201 (2 of 15 animals, 13%) and diltiazem (1 of 9 animals, 11%) groups compared to the vehicle group (8 of 14 animals, 57%). SIGNIFICANCE Induction of VA in an experimental model was achieved with a low dose of isoproterenol under Ca(2+) loading. K201 markedly suppressed both the isoproterenol-induced and the reperfusion-induced VAs, whereas diltiazem did not suppress the isoproterenol-induced VA. The results suggest that both VAs are related to early after depolarization (EAD) and indicate that K201 has the potential to suppress EAD by stabilizing RyR2 to mediate Ca(2+) release from the sarcoplasmic reticulum and acting as a multiple-channel blocker.
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Affiliation(s)
- Naoyuki Otani
- Department of Cardiovascular Medicine, Dokkyo Medical University, Kitakobayashi, Tochigi, Japan
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20
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Abstract
Cardiac myocyte function is dependent on the synchronized movements of Ca(2+) into and out of the cell, as well as between the cytosol and sarcoplasmic reticulum. These movements determine cardiac rhythm and regulate excitation-contraction coupling. Ca(2+) cycling is mediated by a number of critical Ca(2+)-handling proteins and transporters, such as L-type Ca(2+) channels (LTCCs) and sodium/calcium exchangers in the sarcolemma, and sarcoplasmic/endoplasmic reticulum calcium ATPase 2a (SERCA2a), ryanodine receptors, and cardiac phospholamban in the sarcoplasmic reticulum. The entry of Ca(2+) into the cytosol through LTCCs activates the release of Ca(2+) from the sarcoplasmic reticulum through ryanodine receptor channels and initiates myocyte contraction, whereas SERCA2a and cardiac phospholamban have a key role in sarcoplasmic reticulum Ca(2+) sequesteration and myocyte relaxation. Excitation-contraction coupling is regulated by phosphorylation of Ca(2+)-handling proteins. Abnormalities in sarcoplasmic reticulum Ca(2+) cycling are hallmarks of heart failure and contribute to the pathophysiology and progression of this disease. Correcting impaired intracellular Ca(2+) cycling is a promising new approach for the treatment of heart failure. Novel therapeutic strategies that enhance myocyte Ca(2+) homeostasis could prevent and reverse adverse cardiac remodeling and improve clinical outcomes in patients with heart failure.
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Abstract
Metabolic syndrome is characterized by a combination of obesity, hypertension, insulin resistance, dyslipidemia, and impaired glucose tolerance. This multifaceted syndrome is often accompanied by a hyperdynamic circulatory state characterized by increased blood pressure, total blood volume, cardiac output, and metabolic tissue demand. Experimental, epidemiological, and clinical studies have demonstrated that patients with metabolic syndrome have significantly elevated cardiovascular morbidity and mortality rates. One of the main and frequent complications seen in metabolic syndrome is cardiovascular disease. The primary endpoints of cardiometabolic risk are coronary and peripheral arterial disease, myocardial infarction, congestive heart failure, arrhythmia, and stroke. Alterations in expression and/or functioning of several key proteins involved in regulating and maintaining ionic homeostasis can cause cardiac disturbances. One such group of proteins is known as ryanodine receptors (intracellular calcium release channels), which are the major channels through which Ca(2+) ions leave the sarcoplasmic reticulum, leading to cardiac muscle contraction. The economic cost of metabolic syndrome and its associated complications has a significant effect on health care budgets. Improvements in body weight, blood lipid profile, and hyperglycemia can reduce cardiometabolic risk. However, constant hyperadrenergic stimulation still contributes to the burden of disease. Normalization of the hyperdynamic circulatory state with conventional therapies is the most reasonable therapeutic strategy to date. JTV519 (K201) is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It appears to be very effective in not only preventing but also in reversing the characteristic myocardial changes and preventing lethal arrhythmias. It is also a unique candidate to improve diastolic heart failure in metabolic syndrome.
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Affiliation(s)
- U Deniz Dincer
- Department of Pharmacology, Ufuk University School of Medicine. Mevlana Bulvari, Balgat, Ankara, Turkey
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22
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Abstract
Atrial fibrillation is the most common type of cardiac arrhythmia, and is responsible for substantial morbidity and mortality in the general population. Current treatments have moderate efficacy and considerable risks, especially of pro-arrhythmia, highlighting the need for new therapeutic strategies. In recent years, substantial efforts have been invested in developing novel treatments that target the underlying molecular determinants of atrial fibrillation, and several new compounds are under development. This Review focuses on the mechanistic rationale for the development of new anti-atrial fibrillation drugs, on the molecular and structural motifs that they target and on the results obtained so far in experimental and clinical studies.
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Alternative strategies in arrhythmia therapy: evaluation of Na/Ca exchange as an anti-arrhythmic target. Pharmacol Ther 2011; 134:26-42. [PMID: 22197992 DOI: 10.1016/j.pharmthera.2011.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 11/22/2011] [Accepted: 11/22/2011] [Indexed: 01/08/2023]
Abstract
The search for alternative anti-arrhythmic strategies is fueled by an unmet medical need as well as by the opportunities arising from identification of novel targets and novel drugs. Na/Ca exchange is a potential target involved in several types of arrhythmias, such as those related to ischemia-reperfusion, heart failure and also some forms of genetic arrhythmias. Inhibition of Na/Ca exchange is theoretically not only anti-arrhythmic but also increases cellular Ca(2+) content. This could be an advantage in conditions of low inotropy, such as in heart failure, but may also worsen conditions such as the recovery from ischemia or relaxation abnormalities. With the available drugs such as KB-R7943 and SEA-0400 these theories have now been tested in a number of cellular and in vivo models. Experience is overall rather positive and seems less hampered by the potential drawbacks than expected. This may be because the currently available drugs are not highly selective, with additional benefit derived from concurrent effects. While this precludes a definite answer regarding the benefit of a pure NCX inhibitor, they indicate that Na/Ca exchange inhibition as part of a multi-target strategy is an avenue to be considered. Such studies will need further 'bench' work and testing in relevant preclinical models, including chronic disease.
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Burashnikov A, Antzelevitch C. Novel pharmacological targets for the rhythm control management of atrial fibrillation. Pharmacol Ther 2011; 132:300-13. [PMID: 21867730 PMCID: PMC3205214 DOI: 10.1016/j.pharmthera.2011.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 08/05/2011] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is a growing clinical problem associated with increased morbidity and mortality. Development of safe and effective pharmacological treatments for AF is one of the greatest unmet medical needs facing our society. In spite of significant progress in non-pharmacological AF treatments (largely due to the use of catheter ablation techniques), anti-arrhythmic agents (AADs) remain first line therapy for rhythm control management of AF for most AF patients. When considering efficacy, safety and tolerability, currently available AADs for rhythm control of AF are less than optimal. Ion channel inhibition remains the principal strategy for termination of AF and prevention of its recurrence. Practical clinical experience indicates that multi-ion channel blockers are generally more optimal for rhythm control of AF compared to ion channel-selective blockers. Recent studies suggest that atrial-selective sodium channel block can lead to safe and effective suppression of AF and that concurrent inhibition of potassium ion channels may potentiate this effect. An important limitation of the ion channel block approach for AF treatment is that non-electrical factors (largely structural remodeling) may importantly determine the generation of AF, so that "upstream therapy", aimed at preventing or reversing structural remodeling, may be required for effective rhythm control management. This review focuses on novel pharmacological targets for the rhythm control management of AF.
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25
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Stams TRG, Oros A, der Nagel RV, Beekman JDM, Chamberlin P, Dittrich HC, Vos MA. Effects of K201 on repolarization and arrhythmogenesis in anesthetized chronic atrioventricular block dogs susceptible to dofetilide-induced torsade de pointes. Eur J Pharmacol 2011; 672:126-34. [PMID: 22001562 DOI: 10.1016/j.ejphar.2011.09.180] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 09/21/2011] [Accepted: 09/24/2011] [Indexed: 11/16/2022]
Abstract
The novel antiarrhythmic drug K201 (4-[3-{1-(4-benzyl)piperidinyl}propionyl]-7-methoxy-2,3,4,5-tetrahydro-1,4-benzothiazepine monohydrochloride) is currently in development for treatment of atrial fibrillation. K201 not only controls intracellular calcium release by the ryanodine receptors, but also possesses a ventricular action that might predispose to torsade de pointes arrhythmias. The anti- and proarrhythmic effects of K201 were investigated in the anesthetized canine chronic atrioventricular block model. Two doses of K201 (0.1 and 0.3mg/kg/2 min followed by 0.01 and 0.03 mg/kg/30 min i.v.) were tested in 4 serial experiments in dogs with normally conducted sinus rhythm (n=10) and in torsade de pointes-susceptible dogs with chronic atrioventricular block. Susceptibility was assessed with dofetilide (0.025 mg/kg/5 min i.v.). Beat-to-beat variability of repolarization was quantified as short-term variability of left ventricular monophasic action potential duration. In dogs with normally conducted sinus rhythm, both doses of K201 prolonged ventricular repolarization whereas only the higher dose prolonged atrial repolarization. At chronic atrioventricular block, dofetilide induced torsade de pointes in 9 of 10 dogs. K201 did neither suppress nor prevent dofetilide-induced torsade de pointes. K201 dose-dependently prolonged ventricular repolarization. In contrary to the lower dose, the higher dose did increase beat-to-beat variability of repolarization (from 1.2 ± 0.3 to 2.9 ± 0.8 ms, P<0.05) and resulted in spontaneous, repetitive torsade de pointes arrhythmias in 1 of 7 dogs; Programmed electrical stimulation resulted in torsade de pointes in 2 more dogs. In conclusion, both doses of K201 showed a class III effect. No relevant antiarrhythmic effects against dofetilide-induced torsade de pointes were seen. Only at the higher dose a proarrhythmic signal was observed.
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Affiliation(s)
- Thom R G Stams
- Department of Medical Physiology, Division Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands.
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Abstract
Antiarrhythmic drugs are a group of pharmaceuticals that suppress or prevent abnormal heart rhythms, which are often associated with substantial morbidity and mortality. Current antiarrhythmic drugs that typically target plasma membrane ion channels have limited clinical success and in some cases have been described as being pro-arrhythmic. However, recent studies suggest that pathological release of calcium (Ca(2+)) from the sarcoplasmic reticulum via cardiac ryanodine receptors (RyR2) could represent a promising target for antiarrhythmic therapy. Diastolic SR Ca(2+) release has been linked to arrhythmogenesis in both the inherited arrhythmia syndrome 'catecholaminergic polymorphic ventricular tachycardia' and acquired forms of heart disease (eg, atrial fibrillation, heart failure). Several classes of pharmaceuticals have been shown to reduce abnormal RyR2 activity and may confer protection against triggered arrhythmias through reduction of SR Ca(2+) leak. In this review, we will evaluate the current pharmacological methods for stabilizing RyR2 and suggest treatment modalities based on current evidence of molecular mechanisms.
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Workman AJ, Smith GL, Rankin AC. Mechanisms of termination and prevention of atrial fibrillation by drug therapy. Pharmacol Ther 2011; 131:221-41. [PMID: 21334377 DOI: 10.1016/j.pharmthera.2011.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 02/09/2011] [Indexed: 01/13/2023]
Abstract
Atrial fibrillation (AF) is a disorder of the rhythm of electrical activation of the cardiac atria. It is the most common cardiac arrhythmia, has multiple aetiologies, and increases the risk of death from stroke. Pharmacological therapy is the mainstay of treatment for AF, but currently available anti-arrhythmic drugs have limited efficacy and safety. An improved understanding of how anti-arrhythmic drugs affect the electrophysiological mechanisms of AF initiation and maintenance, in the setting of the different cardiac diseases that predispose to AF, is therefore required. A variety of animal models of AF has been developed, to represent and control the pathophysiological causes and risk factors of AF, and to permit the measurement of detailed and invasive parameters relating to the associated electrophysiological mechanisms of AF. The purpose of this review is to examine, consolidate and compare available relevant data on in-vivo electrophysiological mechanisms of AF suppression by currently approved and investigational anti-arrhythmic drugs in such models. These include the Vaughan Williams class I-IV drugs, namely Na(+) channel blockers, β-adrenoceptor antagonists, action potential prolonging drugs, and Ca(2+) channel blockers; the "upstream therapies", e.g., angiotensin converting enzyme inhibitors, statins and fish oils; and a variety of investigational drugs such as "atrial-selective" multiple ion channel blockers, gap junction-enhancers, and intracellular Ca(2+)-handling modulators. It is hoped that this will help to clarify the main electrophysiological mechanisms of action of different and related drug types in different disease settings, and the likely clinical significance and potential future exploitation of such mechanisms.
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Affiliation(s)
- A J Workman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8TA, United Kingdom.
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Dobrev D, Voigt N, Wehrens XHT. The ryanodine receptor channel as a molecular motif in atrial fibrillation: pathophysiological and therapeutic implications. Cardiovasc Res 2010; 89:734-43. [PMID: 20943673 DOI: 10.1093/cvr/cvq324] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with substantial morbidity and mortality. It causes profound changes in sarcoplasmic reticulum (SR) Ca(2+) homeostasis, including ryanodine receptor channel dysfunction and diastolic SR Ca(2+) leak, which might contribute to both decreased contractile function and increased propensity to atrial arrhythmias. In this review, we will focus on the molecular basis of ryanodine receptor channel dysfunction and enhanced diastolic SR Ca(2+) leak in AF. The potential relevance of increased incidence of spontaneous SR Ca(2+) release for both AF induction and/or maintenance and the development of novel mechanism-based therapeutic approaches will be discussed.
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Affiliation(s)
- Dobromir Dobrev
- Division of Experimental Cardiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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30
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Govindan M, Savelieva I, Catanchin A, Camm AJ. Atrial fibrillation-the final frontier. J Cardiovasc Pharmacol Ther 2010; 15:36S-50S. [PMID: 20940451 DOI: 10.1177/1074248410371947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and represents a significant health care issue. The diagnosis and management of AF uses a significant proportion of the health care budget and is responsible for substantial morbidity and mortality. Restoration and maintenance of sinus rhythm is still an important treatment option for symptomatic AF. Anti-arrhythmic drugs (AADs) have had inconsistent results for the prevention of recurrent AF and have been hampered by significant adverse effects. Catheter ablation has rapidly evolved and is fast becoming an alternative for AF prevention. Although multiple treatment options exist, no single modality is effective for all patients. This review outlines best current practice for AF prevention and future perspectives, focusing on new and promising developments in antiarrhythmic drug therapy, strategies for ablation therapy, and forms of hybrid therapy that may offer improved outcomes in selected patients.
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Affiliation(s)
- Malini Govindan
- Division of Cardiac & Vascular Sciences, St George's University of London, London, UK
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31
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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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New pharmacological targets and treatments for atrial fibrillation. Trends Pharmacol Sci 2010; 31:364-71. [PMID: 20605645 DOI: 10.1016/j.tips.2010.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 04/30/2010] [Accepted: 05/03/2010] [Indexed: 11/24/2022]
Abstract
Atrial fibrillation (AF) is an arrhythmia of growing clinical concern that is increasing in prevalence and is associated with significant morbidity and mortality. Pharmacological agents remain the first-line therapy for the AF patient, and the potential advantages of sinus rhythm maintenance motivate continued efforts to identify novel pharmacological means to restore and maintain sinus rhythm. Traditional antiarrhythmic agents only moderately suppress AF and present problematic concerns of proarrhythmia and extracardiac toxicity. Current investigational or recently approved strategies for improving efficacy and safety of anti-AF agents include (i) specific or predominant blockade of atrial ion channels; (ii) "upstream therapies" affecting non-ion channel targets that influence electrical and structural remodeling, inflammation and oxidative stress; (iii) amiodarone derivatives with an improved safety profile; (iv) intracellular calcium handling; and (v) therapies aiming at alleviating conduction disturbances (gap junction coupling enhancers). This review provides a succinct overview of some of these strategies.
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Wehrens XHT, Ather S, Dobrev D. Role of abnormal sarcoplasmic reticulum function in atrial fibrillation. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/thy.10.8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Atrial fibrillation: from ion channels to bedside treatment options. J Electrocardiol 2009; 42:660-70. [DOI: 10.1016/j.jelectrocard.2009.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Indexed: 11/19/2022]
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Dobrev D. Atrial Ca2+ signaling in atrial fibrillation as an antiarrhythmic drug target. Naunyn Schmiedebergs Arch Pharmacol 2009; 381:195-206. [PMID: 19784635 DOI: 10.1007/s00210-009-0457-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 09/11/2009] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmia and is associated with increased morbidity and mortality. Current drugs for AF treatment have moderate efficacy and increase the risk of life-threatening antiarrhythmias, making novel drug development crucial. Newer antiarrhythmic drugs like dronedarone and possibly vernakalant are efficient and may have less proarrhythmic potential. Emerging evidence suggests that abnormal intracellular Ca(2+) signaling is the key contributor to focal firing, substrate evolution, and atrial remodeling during AF. Accordingly, identification of the underlying atrial Ca(2+)-handling abnormalities is expected to discover novel mechanistically based therapeutic targets. This article reviews the molecular mechanisms of altered Ca(2+) signaling in AF and discusses the potential value of novel approaches targeting atrial Ca(2+)-handling abnormalities.
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Affiliation(s)
- Dobromir Dobrev
- Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany.
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Kaneko N, Matsuda R, Hata Y, Shimamoto K. Pharmacological characteristics and clinical applications of K201. ACTA ACUST UNITED AC 2009; 4:126-31. [PMID: 19442077 PMCID: PMC2841427 DOI: 10.2174/157488409788184972] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
K201 is a 1,4-benzothiazepine derivative that is a promising new drug with a strong cardioprotective effect. We initially discovered K201 as an effective suppressant of sudden cardiac cell death due to calcium overload. K201 is a non-specific blocker of sodium, potassium and calcium channels, and its cardioprotective effect is more marked than those of nicorandil, prazosine, propranolol, verapamil and diltiazem. Recently, K201 has also been shown to have activities indicated for treatment of atrial fibrillation, ventricular fibrillation, heart failure and ischemic heart disease, including action as a multiple-channel blocker, inhibition of diastolic Ca(2+) release from the sarcoplasmic reticulum, suppression of spontaneous Ca(2+) sparks and Ca(2+) waves, blockage of annexin V and provision of myocardial protection, and improvement of norepinephrine-induced diastolic dysfunction. Here, we describe the pharmacological characteristics and clinical applications of K201.
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Affiliation(s)
- Noboru Kaneko
- Department of Cardiology and Pneumology, Dokkyo Medical University, Tochigi, Japan.
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Viswanathan MN, Page RL. Pharmacological therapy for atrial fibrillation: current options and new agents. Expert Opin Investig Drugs 2009; 18:417-31. [PMID: 19278302 DOI: 10.1517/13543780902773410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Atrial fibrillation is the most commonly encountered cardiac arrhythmia and is directly or indirectly responsible for considerable mortality, morbidity and health care burden. The available medical therapy is limited by marginal efficacy, end-organ toxicity, as well as the potential for undesired ventricular proarrhythmia. Elucidation of the potential mechanisms that underlie the development of atrial fibrillation may provide new targets for drugs that circumvent the problems associated with current medical options. This review focuses on the current and potential future pharmacological agents directed at rhythm control and maintenance of sinus rhythm.
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Affiliation(s)
- Mohan N Viswanathan
- University of Washington, Division of Cardiology/Cardiac Electrophysiology, Seattle, WA 98195-6422, USA.
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Abstract
Atrial electrical and structural alterations (remodeling) have emerged as key elements in the development of the atrial fibrillation (AF) substrate. Evidence points to abnormalities in intracellular Ca (calcium) handling as crucial links in AF-initiating focal activity and in perpetuation by rapidly firing foci and reentry. This review focuses on the molecular basis of altered Ca handling in AF, with the goal of providing new insights into molecular effective antiarrhythmic therapy.
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Janko S, Dorwarth U, Hoffmann E. Pharmacotherapy of atrial fibrillation: an old option with new possibilities. Expert Opin Pharmacother 2008; 9:913-25. [PMID: 18377335 DOI: 10.1517/14656566.9.6.913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Atrial fibrillation is the most common sustained arrhythmia observed worldwide. Despite modern ablative treatment options, pharmacotherapy remains the first-line therapy in patients with atrial fibrillation. OBJECTIVE Based on recently published guidelines for the management of atrial fibrillation, the present paper reviews the current and emerging concepts of pharmacotherapy in atrial fibrillation. METHODS A MEDLINE search was conducted using the keyword 'atrial fibrillation' and 'drug therapy'. The reviewed literature included clinical trials and published reviews as well as clinical guidelines. RESULTS The mainstay of atrial fibrillation therapy is the prevention of thromboembolic events. With growing knowledge of the pathophysiology of atrial fibrillation new drug targets have been identified that promise improved outcomes in atrial fibrillation management and this will allow individual drug treatment in the near future.
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Affiliation(s)
- Sabine Janko
- Heart Center Munich-Bogenhausen, Department of Cardiology and Intensive Care Unit, Klinikum Bogenhausen, Städtisches Klinikum München GmbH, Englschalkinger Strasse 77, 89125 Munich, Germany
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Effects of K-201 on the calcium pump and calcium release channel of rat skeletal muscle. Pflugers Arch 2008; 457:171-83. [PMID: 18458945 DOI: 10.1007/s00424-008-0504-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 03/14/2008] [Accepted: 03/21/2008] [Indexed: 10/22/2022]
Abstract
The benzothiazepine derivative K-201 has been suggested as a potential therapeutic agent due to its antiarrhythmogenic action. To understand how the drug alters calcium release from the sarcoplasmic reticulum (SR), we investigated its effects on the SR calcium channel and calcium pump by single channel electrophysiology, whole-cell confocal microscopy, and ATPase activity measurements on control and post-myocardial infarcted (PMI) rat skeletal muscle. In bilayers, K-201 induced two subconductance states corresponding to approximately 24% (S(1)) and approximately 13% (S(2)) of the maximum conductance. Dependence of event frequency and of time spent in S(1) and S(2) on the drug concentration was biphasic both in control and in PMI rats, with a maximum at 50 microM. At this concentration, the channel spends 26 +/- 4% and 24 +/- 4%, respectively, of the total time in these subconductance states at positive potentials, while no subconductances are observed at negative potentials. K-201 altered the frequency of elementary calcium release events: spark frequency decreased from 0.039 +/- 0.001 to 0.023 +/- 0.001 s(-1) sarcomere(-1), while the frequency of embers increased from 0.011 +/- 0.001 to 0.023 +/- 0.001 s(-1) sarcomere(-1). Embers with different amplitude levels were observed after the addition of the drug. K-201 inhibited the Ca(2+) ATPase characterized by IC(50,contr) = 119 +/- 21 muM and n (Hill,contr) = 1.84 +/- 0.48 for control and IC(50,PMI) = 122 +/- 18 microM and n (Hill,PMI) = 1.97 +/- 0.24 for PMI animals. These results suggest that although K-201 would increase the appearance of subconductance states, the overall calcium release is reduced by the drug. In addition, the effect of K-201 is identical on calcium release channels from control and PMI rats.
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Sood S, Chelu MG, van Oort RJ, Skapura D, Santonastasi M, Dobrev D, Wehrens XHT. Intracellular calcium leak due to FKBP12.6 deficiency in mice facilitates the inducibility of atrial fibrillation. Heart Rhythm 2008; 5:1047-54. [PMID: 18598963 DOI: 10.1016/j.hrthm.2008.03.030] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 03/21/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND Although defective Ca(2+) homeostasis may contribute to arrhythmogenesis in atrial fibrillation (AF), the underlying molecular mechanisms remain poorly understood. Studies in patients with AF revealed that impaired diastolic closure of sarcoplasmic reticulum (SR) Ca(2+)-release channels (ryanodine receptors, RyR2) is associated with reduced levels of the RyR2-inhibitory subunit FKBP12.6. OBJECTIVE The objective of the present study was to test the hypothesis that Ca(2+) leak from the SR through RyR2 increases the propensity for AF in FKBP12.6-deficient (-/-) mice. METHODS Surface electrocardiogram and intracardiac electrograms were recorded simultaneously in FKBP12.6-/- mice and wild-type (WT) littermates. Right atrial programmed stimulation was performed before and after injection of RyR2 antagonist tetracaine (0.5 mg/kg). Intracellular Ca(2+) transients were recorded in atrial myocytes from FKBP12.6-/- and WT mice. RESULTS FKBP12.6-/- mice had structurally normal atria and unaltered expression of key Ca(2+)-handling proteins. AF episodes were inducible in 81% of FKBP12.6-/-, but in only 7% of WT mice (P <.05), and were prevented by tetracaine in all FKBP12.6-/- mice. SR Ca(2+) leak in FKBP12.6-/- myocytes was 53% larger than in WT myocytes, and FKBP12.6-/- myocytes showed increased incidence of spontaneous SR Ca(2+) release events, which could be blocked by tetracaine. CONCLUSION The increased vulnerability to AF in FKBP12.6-/- mice substantiates the notion that defective SR Ca(2+) release caused by abnormal RyR2 and FKBP12.6 interactions may contribute to the initiation or maintenance of atrial fibrillation.
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Affiliation(s)
- Subeena Sood
- Department of Molecular Physiology and Biophysics, Houston, Texas 77030, USA
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Atrial-Selective Approaches for the Treatment of Atrial Fibrillation. J Am Coll Cardiol 2008; 51:787-92. [DOI: 10.1016/j.jacc.2007.08.067] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 07/27/2007] [Accepted: 08/13/2007] [Indexed: 11/22/2022]
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Chen YJ, Chen YC, Wongcharoen W, Lin CI, Chen SA. Effect of K201, a novel antiarrhythmic drug on calcium handling and arrhythmogenic activity of pulmonary vein cardiomyocytes. Br J Pharmacol 2007; 153:915-25. [PMID: 17994112 DOI: 10.1038/sj.bjp.0707564] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Pulmonary veins are the most important focus for the generation of atrial fibrillation. Abnormal calcium homeostasis with ryanodine receptor dysfunction may underlie the arrhythmogenic activity in pulmonary veins. The preferential ryanodine receptor stabilizer (K201) possesses antiarrhythmic effects through calcium regulation. The purpose of this study was to investigate the effects of K201 on the arrhythmogenic activity and calcium regulation of pulmonary vein cardiomyocytes. EXPERIMENTAL APPROACH The ionic currents and intracellular calcium were studied in isolated single cardiomyocytes from rabbit pulmonary vein before and after the administration of K201, by the whole-cell patch clamp and indo-1 fluorimetric ratio techniques. KEY RESULTS K201 (0.1, 0.3, 1 microM) reduced the firing rates in pulmonary vein cardiomyocytes, decreased the amplitudes of the delayed afterdepolarizations and prolonged the action potential duration. K201 decreased the L-type calcium currents, Na(+)/Ca(2+) exchanger currents, transient inward currents and calcium transients. K201 (1 microM, but not 0.1 microM or 0.3 microM) also reduced the sarcoplasmic reticulum calcium content. Moreover, both the pretreatment and administration of K201 (0.3 microM) decreased the isoprenaline (10 nM)-induced arrhythmogenesis in pulmonary veins. CONCLUSIONS AND IMPLICATIONS K201 reduced the arrhythmogenic activity of pulmonary vein cardiomyocytes and attenuated the arrhythmogenicity induced by isoprenaline. These findings may reveal the anti-arrhythmic potential of K201.
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Affiliation(s)
- Y-J Chen
- Division of Cardiovascular Medicine, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan. a9900112@,s15.hinet.net
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Xiao J, Tian X, Jones PP, Bolstad J, Kong H, Wang R, Zhang L, Duff HJ, Gillis AM, Fleischer S, Kotlikoff M, Copello JA, Chen SRW. Removal of FKBP12.6 does not alter the conductance and activation of the cardiac ryanodine receptor or the susceptibility to stress-induced ventricular arrhythmias. J Biol Chem 2007; 282:34828-38. [PMID: 17921453 DOI: 10.1074/jbc.m707423200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 12.6-kDa FK506-binding protein (FKBP12.6) is considered to be a key regulator of the cardiac ryanodine receptor (RyR2), but its precise role in RyR2 function is complex and controversial. In the present study we investigated the impact of FKBP12.6 removal on the properties of the RyR2 channel and the propensity for spontaneous Ca(2+) release and the occurrence of ventricular arrhythmias. Single channel recordings in lipid bilayers showed that FK506 treatment of recombinant RyR2 co-expressed with or without FKBP12.6 or native canine RyR2 did not induce long-lived subconductance states. [(3)H]Ryanodine binding studies revealed that coexpression with or without FKBP12.6 or treatment with or without FK506 did not alter the sensitivity of RyR2 to activation by Ca(2+) or caffeine. Furthermore, single cell Ca(2+) imaging analyses demonstrated that HEK293 cells co-expressing RyR2 and FKBP12.6 or expressing RyR2 alone displayed the same propensity for spontaneous Ca(2+) release or store overload-induced Ca(2+) release (SOICR). FK506 increased the amplitude and decreased the frequency of SOICR in HEK293 cells expressing RyR2 with or without FKBP12.6, indicating that the action of FK506 on SOICR is independent of FKBP12.6. As with recombinant RyR2, the conductance and ligand-gating properties of single RyR2 channels from FKBP12.6-null mice were indistinguishable from those of single wild type channels. Moreover, FKBP12.6-null mice did not exhibit enhanced susceptibility to stress-induced ventricular arrhythmias, in contrast to previous reports. Collectively, our results demonstrate that the loss of FKBP12.6 has no significant effect on the conduction and activation of RyR2 or the propensity for spontaneous Ca(2+) release and stress-induced ventricular arrhythmias.
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Affiliation(s)
- Jianmin Xiao
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Biophysics, University of Calgary, Calgary, AB, T2N 4N1, Canada
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Hunt D, Jones P, Wang R, Chen W, Bolstad J, Chen K, Shimoni Y, Chen S. K201 (JTV519) suppresses spontaneous Ca2+ release and [3H]ryanodine binding to RyR2 irrespective of FKBP12.6 association. Biochem J 2007; 404:431-8. [PMID: 17313373 PMCID: PMC1896290 DOI: 10.1042/bj20070135] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 02/16/2007] [Accepted: 02/22/2007] [Indexed: 11/17/2022]
Abstract
K201 (JTV519), a benzothiazepine derivative, has been shown to possess anti-arrhythmic and cardioprotective properties, but the mechanism of its action is both complex and controversial. It is believed to stabilize the closed state of the RyR2 (cardiac ryanodine receptor) by increasing its affinity for the FKBP12.6 (12.6 kDa FK506 binding protein) [Wehrens, Lehnart, Reiken, Deng, Vest, Cervantes, Coromilas, Landry and Marks (2004) Science 304, 292-296]. In the present study, we investigated the effect of K201 on spontaneous Ca2+ release induced by Ca2+ overload in rat ventricular myocytes and in HEK-293 cells (human embryonic kidney cells) expressing RyR2 and the role of FKBP12.6 in the action of K201. We found that K201 abolished spontaneous Ca2+ release in cardiac myocytes in a concentration-dependent manner. Treating ventricular myocytes with FK506 to dissociate FKBP12.6 from RyR2 did not affect the suppression of spontaneous Ca2+ release by K201. Similarly, K201 was able to suppress spontaneous Ca2+ release in FK506-treated HEK-293 cells co-expressing RyR2 and FKBP12.6. Furthermore, K201 suppressed spontaneous Ca2+ release in HEK-293 cells expressing RyR2 alone and in cells co-expressing RyR2 and FKBP12.6 with the same potency. In addition, K201 inhibited [3H]ryanodine binding to RyR2-wt (wild-type) and an RyR2 mutant linked to ventricular tachycardia and sudden death, N4104K, in the absence of FKBP12.6. These observations demonstrate that FKBP12.6 is not involved in the inhibitory action of K201 on spontaneous Ca2+ release. Our results also suggest that suppression of spontaneous Ca2+ release and the activity of RyR2 contributes, at least in part, to the anti-arrhythmic properties of K201.
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Key Words
- cardiac arrhythmia
- human embryonic kidney cells (hek-293 cells)
- k201 (jtv519)
- 12.6 kda fk506 binding protein (fkbp12.6)
- ryanodine receptor
- spontaneous ca2+ release
- arvd2, arrhythmogenic right ventricular dysplasia type 2
- cpvt, catecholaminergic polymorphic ventricular tachycardia
- dad, delayed afterdepolarization
- fkbp12.6, 12.6 kda fk506 binding protein
- flp, flippase
- frt, flp recombinase target
- fura 2/am, fura 2 acetoxymethyl ester
- hek-293 cells, human embryonic kidney cells
- ki, knock-in
- ko, knockout
- krh, krebs–ringer–hepes
- ryr, ryanodine receptor
- ryr2, cardiac ryr
- soicr, store-overload-induced ca2+ release
- sr, sarcoplasmic reticulum
- sv40, simian virus 40
- wt, wild-type
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Affiliation(s)
- Donald J. Hunt
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Peter P. Jones
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Ruiwu Wang
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Wenqian Chen
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Jeff Bolstad
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Keyun Chen
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Yakhin Shimoni
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - S. R. Wayne Chen
- *Department of Physiology and Biophysics, University of Calgary, Calgary, AB, Canada T2N 4N1
- †Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
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Abstract
Atrial fibrillation is the most common cardiac arrhythmia and is a major cause of cardiovascular morbidity and mortality in the Western world. Present pharmacological options are limited by inefficacy, proarrhythmia and end-organ toxicity. Enhanced understanding of the underlying causes of this pleotropic entity may allow the creation of targeted drugs that avoid the pitfalls of current options. This review concentrates on both the classical and novel pharmacological therapies aimed at maintaining sinus rhythm.
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Affiliation(s)
- Kristen K Patton
- University of Washington Medical Center, Division of Cardiology, 1959 NE Pacific Street, Box 356422, Seattle, WA 98122, USA.
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Kaneko N, Matsuda R, Ohtani N, Nakajima T, Arikawa T, Suzuki H, Toyoda S, Kikuchi M, Hata Y, Abe S, Taguchi I, Shimamoto K. K201 Improves norepinephrine-induced diastolic dysfunction with preserved ejection fraction. Drug Dev Res 2007. [DOI: 10.1002/ddr.20153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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