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Needs D, Wu T, Nguyen HX, Henriquez CS, Bursac N. Prokaryotic voltage-gated sodium channels are more effective than endogenous Na v1.5 channels in rescuing cardiac action potential conduction: an in silico study. Am J Physiol Heart Circ Physiol 2023; 325:H1178-H1192. [PMID: 37737736 PMCID: PMC10908372 DOI: 10.1152/ajpheart.00287.2023] [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: 05/16/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Methods to augment Na+ current in cardiomyocytes hold potential for the treatment of various cardiac arrhythmias involving conduction slowing. Because the gene coding cardiac Na+ channel (Nav1.5) is too large to fit in a single adeno-associated virus (AAV) vector, new gene therapies are being developed to enhance endogenous Nav1.5 current (by overexpression of chaperon molecules or use of multiple AAV vectors) or to exogenously introduce prokaryotic voltage-gated Na+ channels (BacNav) whose gene size is significantly smaller than that of the Nav1.5. In this study, based on experimental measurements in heterologous expression systems, we developed an improved computational model of the BacNav channel, NavSheP D60A. We then compared in silico how NavSheP D60A expression vs. Nav1.5 augmentation affects the electrophysiology of cardiac tissue. We found that the incorporation of BacNav channels in both adult guinea pig and human cardiomyocyte models increased their excitability and reduced action potential duration. When compared with equivalent augmentation of Nav1.5 current in simulated settings of reduced tissue excitability, the addition of the BacNav current was superior in improving the safety of conduction under conditions of current source-load mismatch, reducing the vulnerability to unidirectional conduction block during premature pacing, preventing the instability and breakup of spiral waves, and normalizing the conduction and ECG in Brugada syndrome tissues with mutated Nav1.5. Overall, our studies show that compared with a potential enhancement of the endogenous Nav1.5 current, expression of the BacNav channels with their slower inactivation kinetics can provide greater anti-arrhythmic benefits in hearts with compromised action potential conduction.NEW & NOTEWORTHY Slow action potential conduction is a common cause of various cardiac arrhythmias; yet, current pharmacotherapies cannot augment cardiac conduction. This in silico study compared the efficacy of recently proposed antiarrhythmic gene therapy approaches that increase peak sodium current in cardiomyocytes. When compared with the augmentation of endogenous sodium current, expression of slower-inactivating bacterial sodium channels was superior in preventing conduction block and arrhythmia induction. These results further the promise of antiarrhythmic gene therapies targeting sodium channels.
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Affiliation(s)
- Daniel Needs
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Tianyu Wu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Hung X Nguyen
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Craig S Henriquez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
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2
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Ahmad B, Skorska A, Wolfien M, Sadraddin H, Lemcke H, Vasudevan P, Wolkenhauer O, Steinhoff G, David R, Gaebel R. The Effects of Hypoxic Preconditioned Murine Mesenchymal Stem Cells on Post-Infarct Arrhythmias in the Mouse Model. Int J Mol Sci 2022; 23:ijms23168843. [PMID: 36012110 PMCID: PMC9408396 DOI: 10.3390/ijms23168843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
Ventricular arrhythmias associated with myocardial infarction (MI) have a significant impact on mortality in patients following heart attack. Therefore, targeted reduction of arrhythmia represents a therapeutic approach for the prevention and treatment of severe events after infarction. Recent research transplanting mesenchymal stem cells (MSC) showed their potential in MI therapy. Our study aimed to investigate the effects of MSC injection on post-infarction arrhythmia. We used our murine double infarction model, which we previously established, to more closely mimic the clinical situation and intramyocardially injected hypoxic pre-conditioned murine MSC to the infarction border. Thereafter, various types of arrhythmias were recorded and analyzed. We observed a homogenous distribution of all types of arrhythmias after the first infarction, without any significant differences between the groups. Yet, MSC therapy after double infarction led to a highly significant reduction in simple and complex arrhythmias. Moreover, RNA-sequencing of samples from stem cell treated mice after re-infarction demonstrated a significant decline in most arrhythmias with reduced inflammatory pathways. Additionally, following stem-cell therapy we found numerous highly expressed genes to be either linked to lowering the risk of heart failure, cardiomyopathy or sudden cardiac death. Moreover, genes known to be associated with arrhythmogenesis and key mutations underlying arrhythmias were downregulated. In summary, our stem-cell therapy led to a reduction in cardiac arrhythmias after MI and showed a downregulation of already established inflammatory pathways. Furthermore, our study reveals gene regulation pathways that have a potentially direct influence on arrhythmogenesis after myocardial infarction.
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Affiliation(s)
- Beschan Ahmad
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
| | - Anna Skorska
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
| | - Markus Wolfien
- Department of Systems Biology and Bioinformatics, University of Rostock, 18051 Rostock, Germany
- Institute for Medical Informatics and Biometry, Faculty of Medicine Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Haval Sadraddin
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
| | - Heiko Lemcke
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
| | - Praveen Vasudevan
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
| | - Olaf Wolkenhauer
- Department of Systems Biology and Bioinformatics, University of Rostock, 18051 Rostock, Germany
| | - Gustav Steinhoff
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
| | - Robert David
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
- Correspondence: ; Tel.: +49-381-4988973; Fax: +49-381-4988970
| | - Ralf Gaebel
- Department of Cardiac Surgery, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, Interdisciplinary Faculty, Rostock University, 18059 Rostock, Germany
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3
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Naumova N, Iop L. Bioengineering the Cardiac Conduction System: Advances in Cellular, Gene, and Tissue Engineering for Heart Rhythm Regeneration. Front Bioeng Biotechnol 2021; 9:673477. [PMID: 34409019 PMCID: PMC8365186 DOI: 10.3389/fbioe.2021.673477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/24/2021] [Indexed: 01/01/2023] Open
Abstract
Heart rhythm disturbances caused by different etiologies may affect pediatric and adult patients with life-threatening consequences. When pharmacological therapy is ineffective in treating the disturbances, the implantation of electronic devices to control and/or restore normal heart pacing is a unique clinical management option. Although these artificial devices are life-saving, they display many limitations; not least, they do not have any capability to adapt to somatic growth or respond to neuroautonomic physiological changes. A biological pacemaker could offer a new clinical solution for restoring heart rhythms in the conditions of disorder in the cardiac conduction system. Several experimental approaches, such as cell-based, gene-based approaches, and the combination of both, for the generation of biological pacemakers are currently established and widely studied. Pacemaker bioengineering is also emerging as a technology to regenerate nodal tissues. This review analyzes and summarizes the strategies applied so far for the development of biological pacemakers, and discusses current translational challenges toward the first-in-human clinical application.
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Affiliation(s)
- Nataliia Naumova
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Padua, Italy
| | - Laura Iop
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Padua, Italy
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Végh AMD, Verkerk AO, Cócera Ortega L, Wang J, Geerts D, Klerk M, Lodder K, Nobel R, Tijsen AJ, Devalla HD, Christoffels VM, Medina-Ramírez M, Smits AM, Tan HL, Wilders R, Goumans MJTH, Boink GJJ. Toward Biological Pacing by Cellular Delivery of Hcn2/SkM1. Front Physiol 2021; 11:588679. [PMID: 33488393 PMCID: PMC7815531 DOI: 10.3389/fphys.2020.588679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 12/08/2020] [Indexed: 01/18/2023] Open
Abstract
Electronic pacemakers still face major shortcomings that are largely intrinsic to their hardware-based design. Radical improvements can potentially be generated by gene or cell therapy-based biological pacemakers. Our previous work identified adenoviral gene transfer of Hcn2 and SkM1, encoding a "funny current" and skeletal fast sodium current, respectively, as a potent combination to induce short-term biological pacing in dogs with atrioventricular block. To achieve long-term biological pacemaker activity, alternative delivery platforms need to be explored and optimized. The aim of the present study was therefore to investigate the functional delivery of Hcn2/SkM1 via human cardiomyocyte progenitor cells (CPCs). Nucleofection of Hcn2 and SkM1 in CPCs was optimized and gene transfer was determined for Hcn2 and SkM1 in vitro. The modified CPCs were analyzed using patch-clamp for validation and characterization of functional transgene expression. In addition, biophysical properties of Hcn2 and SkM1 were further investigated in lentivirally transduced CPCs by patch-clamp analysis. To compare both modification methods in vivo, CPCs were nucleofected or lentivirally transduced with GFP and injected in the left ventricle of male NOD-SCID mice. After 1 week, hearts were collected and analyzed for GFP expression and cell engraftment. Subsequent functional studies were carried out by computational modeling. Both nucleofection and lentiviral transduction of CPCs resulted in functional gene transfer of Hcn2 and SkM1 channels. However, lentiviral transduction was more efficient than nucleofection-mediated gene transfer and the virally transduced cells survived better in vivo. These data support future use of lentiviral transduction over nucleofection, concerning CPC-based cardiac gene delivery. Detailed patch-clamp studies revealed Hcn2 and Skm1 current kinetics within the range of previously reported values of other cell systems. Finally, computational modeling indicated that CPC-mediated delivery of Hcn2/SkM1 can generate stable pacemaker function in human ventricular myocytes. These modeling studies further illustrated that SkM1 plays an essential role in the final stage of diastolic depolarization, thereby enhancing biological pacemaker functioning delivered by Hcn2. Altogether these studies support further development of CPC-mediated delivery of Hcn2/SkM1 and functional testing in bradycardia models.
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Affiliation(s)
- Anna M D Végh
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands.,Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Lucía Cócera Ortega
- Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jianan Wang
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Dirk Geerts
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Mischa Klerk
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Kirsten Lodder
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Ruby Nobel
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Anke J Tijsen
- Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Harsha D Devalla
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Max Medina-Ramírez
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Anke M Smits
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Hanno L Tan
- Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Netherlands Heart Institute, Utrecht, Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Marie José T H Goumans
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Gerard J J Boink
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Clinical Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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CD271 + Human Mesenchymal Stem Cells Show Antiarrhythmic Effects in a Novel Murine Infarction Model. Cells 2019; 8:cells8121474. [PMID: 31757119 PMCID: PMC6953053 DOI: 10.3390/cells8121474] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 12/21/2022] Open
Abstract
Background: Ventricular arrhythmias (VA) are a common cause of sudden death after myocardial infarction (MI). Therefore, developing new therapeutic methods for the prevention and treatment of VA is of prime importance. Methods: Human bone marrow derived CD271+ mesenchymal stem cells (MSC) were tested for their antiarrhythmic effect. This was done through the development of a novel mouse model using an immunocompromised Rag2−/− γc−/− mouse strain subjected to myocardial “infarction-reinfarction”. The mice underwent a first ischemia-reperfusion through the left anterior descending (LAD) artery closure for 45 min with a subsequent second permanent LAD ligation after seven days from the first infarct. Results: This mouse model induced various types of VA detected with continuous electrocardiogram (ECG) monitoring via implanted telemetry device. The immediate intramyocardial delivery of CD271+ MSC after the first MI significantly reduced VA induced after the second MI. Conclusions: In addition to the clinical relevance, more closely reflecting patients who suffer from severe ischemic heart disease and related arrhythmias, our new mouse model bearing reinfarction warrants the time required for stem cell engraftment and for the first time enables us to analyze and verify significant antiarrhythmic effects of human CD271+ stem cells in vivo.
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6
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Cardiomyocyte Progenitor Cells as a Functional Gene Delivery Vehicle for Long-Term Biological Pacing. Molecules 2019; 24:molecules24010181. [PMID: 30621310 PMCID: PMC6337610 DOI: 10.3390/molecules24010181] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/28/2018] [Accepted: 12/31/2018] [Indexed: 01/16/2023] Open
Abstract
Sustained pacemaker function is a challenge in biological pacemaker engineering. Human cardiomyocyte progenitor cells (CMPCs) have exhibited extended survival in the heart after transplantation. We studied whether lentivirally transduced CMPCs that express the pacemaker current If (encoded by HCN4) can be used as functional gene delivery vehicle in biological pacing. Human CMPCs were isolated from fetal hearts using magnetic beads coated with Sca-1 antibody, cultured in nondifferentiating conditions, and transduced with a green fluorescent protein (GFP)- or HCN4-GFP-expressing lentivirus. A patch-clamp analysis showed a large hyperpolarization-activated, time-dependent inward current (−20 pA/pF at −140 mV, n = 14) with properties typical of If in HCN4-GFP-expressing CMPCs. Gap-junctional coupling between CMPCs and neonatal rat ventricular myocytes (NRVMs) was demonstrated by efficient dye transfer and changes in spontaneous beating activity. In organ explant cultures, the number of preparations showing spontaneous beating activity increased from 6.3% in CMPC/GFP-injected preparations to 68.2% in CMPC/HCN4-GFP-injected preparations (P < 0.05). Furthermore, in CMPC/HCN4-GFP-injected preparations, isoproterenol induced a significant reduction in cycle lengths from 648 ± 169 to 392 ± 71 ms (P < 0.05). In sum, CMPCs expressing HCN4-GFP functionally couple to NRVMs and induce physiologically controlled pacemaker activity and may therefore provide an attractive delivery platform for sustained pacemaker function.
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7
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Driessen HE, van Veen TAB, Boink GJJ. Emerging molecular therapies targeting myocardial infarction-related arrhythmias. Europace 2017; 19:518-528. [PMID: 28431070 DOI: 10.1093/europace/euw198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/06/2016] [Indexed: 12/18/2022] Open
Abstract
Cardiac disease is the leading cause of death in the developed world. Ventricular arrhythmias associated with myocardial ischaemia and/or infarction are a major contributor to cardiovascular mortality, and require improved prevention and treatment. Drugs, devices, and radiofrequency catheter ablation have made important inroads, but have significant limitations ranging from incomplete success to undesired toxicities and major side effects. These limitations derive from the nature of the intervention. Drugs are frequently ineffective, target the entire heart, and often do not deal with the specific arrhythmia trigger or substrate. Devices can terminate rapid rhythms but at best indirectly affect the underlying disease, while ablation, even when appropriately targeted, induces additional tissue damage. In contrast, exploration of gene and cell therapies are expected to provide a targeted, non-destructive, and potentially regenerative approach to ischaemia- and infarction-related arrhythmias. Although these approaches are in the early stages of development, they carry substantial potential to advance arrhythmia prevention and treatment.
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Affiliation(s)
- Helen E Driessen
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Toon A B van Veen
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gerard J J Boink
- Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.,Netherlands Heart Institute, Utrecht, The Netherlands
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8
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Lugenbiel P, Schweizer PA, Katus HA, Thomas D. Antiarrhythmic gene therapy - will biologics replace catheters, drugs and devices? Eur J Pharmacol 2016; 791:264-273. [PMID: 27593579 DOI: 10.1016/j.ejphar.2016.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/08/2016] [Accepted: 09/01/2016] [Indexed: 01/08/2023]
Abstract
The clinical management of heart rhythm disorders still constitutes a major challenge. The development of alternatives to current approaches is of significant interest in order to establish more effective therapies that increase quality of life and reduce symptoms and hospitalizations. Over the past two decades the mechanistic understanding of pathophysiological pathways underlying cardiac arrhythmias has advanced profoundly, opening up novel avenues for mechanism-based therapeutic approaches. In particular, gene therapy offers greater selectivity than small molecule-based or interventional treatment. The gene of interest is packaged into viral or non-viral carriers and delivered to the target area via direct injection or using catheter-based techniques, providing the advantage of site-restricted action in contrast to systemic application of drugs. This work summarizes the current knowledge on mechanistic background, application strategies, and preclinical outcome of antiarrhythmic gene therapy for atrial fibrillation, ventricular tachycardia, and modulation of sinus node function.
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Affiliation(s)
- Patrick Lugenbiel
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
| | - Patrick A Schweizer
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany.
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Affiliation(s)
- Christine M Albert
- From Harvard Medical School, Center for Arrhythmia Prevention, Division of Cardiovascular and Preventive Medicine (C.M.A.), and Department of Medicine, Harvard Medical School, Cardiac Arrhythmia Program, Division of Cardiovascular Medicine (W.G.S.), Brigham and Women's Hospital, Boston, MA.
| | - William G Stevenson
- From Harvard Medical School, Center for Arrhythmia Prevention, Division of Cardiovascular and Preventive Medicine (C.M.A.), and Department of Medicine, Harvard Medical School, Cardiac Arrhythmia Program, Division of Cardiovascular Medicine (W.G.S.), Brigham and Women's Hospital, Boston, MA
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Abstract
Efforts to use gene therapy to create a biological pacemaker as an adjunct or replacement of electronic pacemakers have been ongoing for about 15 years. For the past decade, most of these efforts have focused on the hyperpolarization-activated cyclic nucleotide gated-(HCN) gene family of channels alone or in combination with other genes. The HCN gene family is the molecular correlate of the cardiac pacemaker current, If. It is a suitable basis for a biological pacemaker because it generates a depolarizing inward current primarily during diastole and is directly regulated by cyclic adenosine monophosphate (cAMP), thereby incorporating autonomic responsiveness. However, biological pacemakers based either on native HCN channels or on mutated HCN channels designed to optimize biophysical characteristics have failed to attain the desired basal and maximal physiological heart rates in large animals. More recent work has explored dual gene therapy approaches, combining an HCN variant with another gene to reduce outward current, increase an additional inward current, or enhance cAMP synthesis. Several of these dual gene therapy approaches have demonstrated appropriate basal and maximal heart rates with little or no reliance on a backup electronic pacemaker during the period of study. Future research, besides examining the efficacy of other gene combinations, will need to consider the additional issues of safety and persistence of the viral vectors often used to deliver these genes to a specific cardiac region.
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Affiliation(s)
- Gerard J. J. Boink
- Heart Center, Department of Clinical & Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- Netherlands Heart Institute, ICIN, Utrecht, the Netherlands
| | - Richard B. Robinson
- Department of Pharmacology, Center for Molecular Therapeutics, Columbia University, New York, NY, USA
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Boink GJJ, Duan L, Nearing BD, Shlapakova IN, Sosunov EA, Anyukhovsky EP, Bobkov E, Kryukova Y, Ozgen N, Danilo P, Cohen IS, Verrier RL, Robinson RB, Rosen MR. HCN2/SkM1 gene transfer into canine left bundle branch induces stable, autonomically responsive biological pacing at physiological heart rates. J Am Coll Cardiol 2013; 61:1192-201. [PMID: 23395072 DOI: 10.1016/j.jacc.2012.12.031] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Revised: 12/07/2012] [Accepted: 12/18/2012] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This study sought to test the hypothesis that hyperpolarization-activated cyclic nucleotide-gated (HCN)-based biological pacing might be improved significantly by hyperpolarizing the action potential (AP) threshold via coexpression of the skeletal muscle sodium channel 1 (SkM1). BACKGROUND Gene-based biological pacemakers display effective in vivo pacemaker function. However, approaches used to date have failed to manifest optimal pacemaker properties, defined as basal beating rates of 60 to 90 beats/min, a brisk autonomic response achieving maximal rates of 130 to 160 beats/min, and low to absent electronic backup pacing. METHODS We implanted adenoviral SkM1, HCN2, or HCN2/SkM1 constructs into left bundle branches (LBB) or left ventricular (LV) epicardium of atrioventricular-blocked dogs. RESULTS During stable peak gene expression on days 5 to 7, HCN2/SkM1 LBB-injected dogs showed highly stable in vivo pacemaker activity superior to SkM1 or HCN2 alone and superior to LV-implanted dogs with regard to beating rates (resting approximately 80 beats/min; maximum approximately 130 beats/min), no dependence on electronic backup pacing, and enhanced modulation of pacemaker function during circadian rhythm or epinephrine infusion. In vitro isolated LV of dogs overexpressing SkM1 manifested a significantly more negative AP threshold. CONCLUSIONS LBB-injected HCN2/SkM1 potentially provides a more clinically suitable biological pacemaker strategy than other reported constructs. This superiority is attributable to the more negative AP threshold and injection into the LBB.
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Affiliation(s)
- Gerard J J Boink
- Department of Pharmacology, Columbia University, New York, NY 10032, USA
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