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Bloothooft M, Verbruggen B, Seibertz F, van der Heyden MAG, Voigt N, de Boer TP. Recording ten-fold larger I Kr conductances with automated patch clamping using equimolar Cs + solutions. Front Physiol 2024; 15:1298340. [PMID: 38328302 PMCID: PMC10847579 DOI: 10.3389/fphys.2024.1298340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/09/2024] [Indexed: 02/09/2024] Open
Abstract
Background: The rapid delayed rectifier potassium current (IKr) is important for cardiac repolarization and is most often involved in drug-induced arrhythmias. However, accurately measuring this current can be challenging in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes because of its small current density. Interestingly, the ion channel conducting IKr, hERG channel, is not only permeable to K+ ions but also to Cs+ ions when present in equimolar concentrations inside and outside of the cell. Methods: In this study, IhERG was measured from Chinese hamster ovary (CHO)-hERG cells and hiPSC-CM using either Cs+ or K+ as the charge carrier. Equimolar Cs+ has been used in the literature in manual patch-clamp experiments, and here, we apply this approach using automated patch-clamp systems. Four different (pre)clinical drugs were tested to compare their effects on Cs+- and K+-based currents. Results: Using equimolar Cs+ solutions gave rise to approximately ten-fold larger hERG conductances. Comparison of Cs+- and K+-mediated currents upon application of dofetilide, desipramine, moxifloxacin, or LUF7244 revealed many similarities in inhibition or activation properties of the drugs studied. Using equimolar Cs+ solutions gave rise to approximately ten-fold larger hERG conductances. In hiPSC-CM, the Cs+-based conductance is larger compared to the known K+-based conductance, and the Cs+ hERG conductance can be inhibited similarly to the K+-based conductance. Conclusion: Using equimolar Cs+ instead of K+ for IhERG measurements in an automated patch-clamp system gives rise to a new method by which, for example, quick scans can be performed on effects of drugs on hERG currents. This application is specifically relevant when such experiments are performed using cells which express small IKr current densities in combination with small membrane capacitances.
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Affiliation(s)
- Meye Bloothooft
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bente Verbruggen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Teun P. de Boer
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
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2
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Ni H, Grandi E. Computational Modeling of Cardiac Electrophysiology. Methods Mol Biol 2024; 2735:63-103. [PMID: 38038844 DOI: 10.1007/978-1-0716-3527-8_5] [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] [Indexed: 12/02/2023]
Abstract
Mathematical modeling and simulation are well-established and powerful tools to integrate experimental data of individual components of cardiac electrophysiology, excitation-contraction coupling, and regulatory signaling pathways, to gain quantitative and mechanistic insight into pathophysiological processes and guide therapeutic strategies. Here, we briefly describe the processes governing cardiac myocyte electrophysiology and Ca2+ handling and their regulation, as well as action potential propagation in tissue. We discuss the models and methods used to describe these phenomena, including procedures for model parameterization and validation, in addition to protocols for model interrogation and analysis and techniques that account for phenotypic variability and parameter uncertainty. Our objective is to provide a summary of basic concepts and approaches as a resource for scientists training in this discipline and for all researchers aiming to gain an understanding of cardiac modeling studies.
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Affiliation(s)
- Haibo Ni
- Department of Pharmacology, University of California, Davis, CA, USA.
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, CA, USA.
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3
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Jin Q, Greenstein JL, Winslow RL. Estimating the probability of early afterdepolarizations and predicting arrhythmic risk associated with long QT syndrome type 1 mutations. Biophys J 2023; 122:4042-4056. [PMID: 37705243 PMCID: PMC10598291 DOI: 10.1016/j.bpj.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/29/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023] Open
Abstract
Early afterdepolarizations (EADs) are action potential (AP) repolarization abnormalities that can trigger lethal arrhythmias. Simulations using biophysically detailed cardiac myocyte models can reveal how model parameters influence the probability of these cellular arrhythmias; however, such analyses can pose a huge computational burden. We have previously developed a highly simplified approach in which logistic regression models (LRMs) map parameters of complex cell models to the probability of ectopic beats. Here, we extend this approach to predict the probability of EADs (P(EAD)) as a mechanistic metric of arrhythmic risk. We use the LRM to investigate how changes in parameters of the slow-activating delayed rectifier current (IKs) affect P(EAD) for 17 different long QT syndrome type 1 (LQTS1) mutations. In this LQTS1 clinical arrhythmic risk prediction task, we compared P(EAD) for these 17 mutations with two other recently published model-based arrhythmia risk metrics (AP morphology metric across populations of myocyte models and transmural repolarization prolongation based on a one-dimensional [1D] tissue-level model). These model-based risk metrics yield similar prediction performance; however, each fails to stratify clinical risk for a significant number of the 17 studied LQTS1 mutations. Nevertheless, an interpretable ensemble model using multivariate linear regression built by combining all of these model-based risk metrics successfully predicts the clinical risk of 17 mutations. These results illustrate the potential of computational approaches in arrhythmia risk prediction.
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Affiliation(s)
- Qingchu Jin
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Joseph L Greenstein
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Raimond L Winslow
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland.
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4
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Alvarez JAE, Jafri MS, Ullah A. Local Control Model of a Human Ventricular Myocyte: An Exploration of Frequency-Dependent Changes and Calcium Sparks. Biomolecules 2023; 13:1259. [PMID: 37627324 PMCID: PMC10452762 DOI: 10.3390/biom13081259] [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: 07/03/2023] [Revised: 08/07/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Calcium (Ca2+) sparks are the elementary events of excitation-contraction coupling, yet they are not explicitly represented in human ventricular myocyte models. A stochastic ventricular cardiomyocyte human model that adapts to intracellular Ca2+ ([Ca2+]i) dynamics, spark regulation, and frequency-dependent changes in the form of locally controlled Ca2+ release was developed. The 20,000 CRUs in this model are composed of 9 individual LCCs and 49 RyRs that function as couplons. The simulated action potential duration at 1 Hz steady-state pacing is ~0.280 s similar to human ventricular cell recordings. Rate-dependence experiments reveal that APD shortening mechanisms are largely contributed by the L-type calcium channel inactivation, RyR open fraction, and [Ca2+]myo concentrations. The dynamic slow-rapid-slow pacing protocol shows that RyR open probability during high pacing frequency (2.5 Hz) switches to an adapted "nonconducting" form of Ca2+-dependent transition state. The predicted force was also observed to be increased in high pacing, but the SR Ca2+ fractional release was lower due to the smaller difference between diastolic and systolic [Ca2+]SR. Restitution analysis through the S1S2 protocol and increased LCC Ca2+-dependent activation rate show that the duration of LCC opening helps modulate its effects on the APD restitution at different diastolic intervals. Ultimately, a longer duration of calcium sparks was observed in relation to the SR Ca2+ loading at high pacing rates. Overall, this study demonstrates the spontaneous Ca2+ release events and ion channel responses throughout various stimuli.
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Affiliation(s)
| | - M. Saleet Jafri
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
| | - Aman Ullah
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
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5
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Benson JM, Wang G, Hutt JA, Wu G, Kaminsky SM, Cram S, Barur R, Donahue JK. Preclinical safety and biodistribution assessment of Ad-KCNH2-G628S administered via atrial painting in New Zealand white rabbits. Basic Clin Pharmacol Toxicol 2023; 133:179-193. [PMID: 37177881 PMCID: PMC10935599 DOI: 10.1111/bcpt.13885] [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: 10/26/2022] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Post-operative atrial fibrillation (POAF) is the most common complication after cardiac surgery. Despite implementation of several pharmacological strategies, incidence of POAF remains at approximately 30%. An adenovirus vector encoding KCNH2-G628S has proven efficacious in a porcine model of AF. In this preclinical study, 1.5 × 1010 or 1.5 × 1012 Ad-KCNH2-G628S vector particles (vp) were applied to the atrial epicardium or 1.5 × 1012 vp were applied to the whole epicardial surface of New Zealand White rabbits. Saline and vector vehicle served as procedure controls. Animals were followed for up to 42 days. Vector genomes persisted in the atria up to 42 days, with no distribution to extra-thoracic organs. There were no adverse effects attributable to test article on standard toxicological endpoints or on blood pressure, left atrial or ventricular ejection fractions, electrocardiographic parameters, or serum IL-6 or troponin concentrations. Mononuclear infiltration of the myocardium of the atrial free walls of low-dose, but not high-dose animals was observed at 7 and 21 days, but these changes did not persist or affect cardiac function. After scaling for heart size, results indicate the test article is safe at doses up to 25 times the maximum proposed for the human clinical trial.
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Affiliation(s)
- Janet M. Benson
- Applied Toxicology Program, Lovelace Biomedical Research Institute, Albuquerque, NM 87108, USA
| | - Gensheng Wang
- Applied Toxicology Program, Lovelace Biomedical Research Institute, Albuquerque, NM 87108, USA
- Baxter International, Inc. Deerfield, IL 60015, USA
| | - Julie A. Hutt
- Greenfield Pathology Services, Inc., Greenfield, IN 46140, USA
| | - Guodong Wu
- Applied Toxicology Program, Lovelace Biomedical Research Institute, Albuquerque, NM 87108, USA
| | - Stephen M. Kaminsky
- Weill Cornell Medicine, Belfer Gene Therapy Core Facility, New York, NY 10021, USA
| | - Sara Cram
- Weill Cornell Medicine, Belfer Gene Therapy Core Facility, New York, NY 10021, USA
| | - Rajeshkumar Barur
- Cardiovascular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - J. Kevin Donahue
- Cardiovascular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
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6
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Asfaw TN, Bondarenko VE. A compartmentalized mathematical model of the β 1- and β 2-adrenergic signaling systems in ventricular myocytes from mouse in heart failure. Am J Physiol Cell Physiol 2023; 324:C263-C291. [PMID: 36468844 DOI: 10.1152/ajpcell.00366.2022] [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: 12/12/2022]
Abstract
Mouse models of heart failure are extensively used to research human cardiovascular diseases. In particular, one of the most common is the mouse model of heart failure resulting from transverse aortic constriction (TAC). Despite this, there are no comprehensive compartmentalized mathematical models that describe the complex behavior of the action potential, [Ca2+]i transients, and their regulation by β1- and β2-adrenergic signaling systems in failing mouse myocytes. In this paper, we develop a novel compartmentalized mathematical model of failing mouse ventricular myocytes after TAC procedure. The model describes well the cell geometry, action potentials, [Ca2+]i transients, and β1- and β2-adrenergic signaling in the failing cells. Simulation results obtained with the failing cell model are compared with those from the normal ventricular myocytes. Exploration of the model reveals the sarcoplasmic reticulum Ca2+ load mechanisms in failing ventricular myocytes. We also show a larger susceptibility of the failing myocytes to early and delayed afterdepolarizations and to a proarrhythmic behavior of Ca2+ dynamics upon stimulation with isoproterenol. The mechanisms of the proarrhythmic behavior suppression are investigated and sensitivity analysis is performed. The developed model can explain the existing experimental data on failing mouse ventricular myocytes and make experimentally testable predictions of a failing myocyte's behavior.
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Affiliation(s)
- Tesfaye Negash Asfaw
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia
| | - Vladimir E Bondarenko
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia.,Neuroscience Institute, Georgia State University, Atlanta, Georgia
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7
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Tajima K, Yamakawa K, Kuwabara Y, Miyazaki C, Sunaga H, Uezono S. Propofol anesthesia decreases the incidence of new-onset postoperative atrial fibrillation compared to desflurane in patients undergoing video-assisted thoracoscopic surgery: A retrospective single-center study. PLoS One 2023; 18:e0285120. [PMID: 37130135 PMCID: PMC10153745 DOI: 10.1371/journal.pone.0285120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/16/2023] [Indexed: 05/03/2023] Open
Abstract
BACKGROUND Postoperative atrial fibrillation (POAF) increases postoperative morbidity, mortality, and length of hospital stay. Propofol is reported to modulate atrial electrophysiology and the cardiac autonomic nervous system. Therefore, we retrospectively examined whether propofol suppresses POAF in patients undergoing video-assisted thoracoscopic surgery (VATS) compared to desflurane. METHODS We retrospectively recruited adult patients who underwent VATS during the period from January 2011 to May 2018 in an academic university hospital. Between continuous propofol and desflurane administration during anesthetic maintenance, we investigated the incidence of new-onset POAF (within 48 hours after surgery) before and after propensity score matching. RESULTS Of the 482 patients, 344 received propofol, and 138 received desflurane during anesthetic maintenance. The incidence of POAF in the propofol group was less than that in the desflurane group (4 [1.2%] vs. 8 patients [5.8%], odds ratio [OR]; 0.161, 95% confidence interval (CI), 0.040-0.653, p = 0.011) in the present study population. After adjustment for propensity score matching (n = 254, n = 127 each group), the incidence of POAF was still less in propofol group than desflurane group (1 [0.8%] vs. 8 patients [6.3%], OR; 0.068, 95% CI: 0.007-0.626, p = 0.018). CONCLUSIONS These retrospective data suggest propofol anesthesia significantly inhibits POAF compared to desflurane anesthesia in patients undergoing VATS. Further prospective studies are needed to elucidate the mechanism of propofol on the inhibition of POAF.
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Affiliation(s)
- Karin Tajima
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kentaro Yamakawa
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Yuki Kuwabara
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Chika Miyazaki
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroshi Sunaga
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Shoichi Uezono
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
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8
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Acacetin as a Potential Protective Compound against Cardiovascular Diseases. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:6265198. [PMID: 35280514 PMCID: PMC8906942 DOI: 10.1155/2022/6265198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 02/08/2022] [Indexed: 12/19/2022]
Abstract
Acacetin (5,7-dihydroxy-4′-methoxyflavone) is the major bioactive component of the traditional Chinese medicine “Snow lotus”. As a natural flavonoid compound, it has been shown to have good pharmacological effects such as anti-inflammatory, anticancer, and anti-obesity. Among them, its prominent role in cardiovascular diseases (CVD) has received extensive attention from scholars in recent years. In this review, the protective effects of acacetin on a variety of cardiovascular diseases, as well as the existing problems and prospects, are discussed and summarized. This review also highlights the great potential of acacetin, a natural-derived Chinese medicine, as a cardiovascular agent candidate.
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9
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Yuasa M, Kojima A, Mi X, Ding WG, Omatsu-Kanbe M, Kitagawa H, Matsuura H. Characterization and functional role of rapid- and slow-activating delayed rectifier K + currents in atrioventricular node cells of guinea pigs. Pflugers Arch 2021; 473:1885-1898. [PMID: 34704178 DOI: 10.1007/s00424-021-02617-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 01/28/2023]
Abstract
The atrioventricular (AV) node is the only conduction pathway where electrical impulse can pass from atria to ventricles and exhibits spontaneous automaticity. This study examined the function of the rapid- and slow-activating delayed rectifier K+ currents (IKr and IKs) in the regulation of AV node automaticity. Isolated AV node cells from guinea pigs were current- and voltage-clamped to record the action potentials and the IKr and IKs current. The expression of IKr or IKs was confirmed in the AV node cells by immunocytochemistry, and the positive signals of both channels were localized mainly on the cell membrane. The basal spontaneous automaticity was equally reduced by E4031 and HMR-1556, selective blockers of IKr and IKs, respectively. The nonselective β-adrenoceptor agonist isoproterenol markedly increased the firing rate of action potentials. In the presence of isoproterenol, the firing rate of action potentials was more effectively reduced by the IKs inhibitor HMR-1556 than by the IKr inhibitor E4031. Both E4031 and HMR-1556 prolonged the action potential duration and depolarized the maximum diastolic potential under basal and β-adrenoceptor-stimulated conditions. IKr was not significantly influenced by β-adrenoceptor stimulation, but IKs was concentration-dependently enhanced by isoproterenol (EC50: 15 nM), with a significant negative voltage shift in the channel activation. These findings suggest that both the IKr and IKs channels might exert similar effects on regulating the repolarization process of AV node action potentials under basal conditions; however, when the β-adrenoceptor is activated, IKs modulation may become more important.
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Affiliation(s)
- Mayumi Yuasa
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Akiko Kojima
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Xinya Mi
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan.
| | - Mariko Omatsu-Kanbe
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Hirotoshi Kitagawa
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
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Lee Y, Park H, Kyung Koo S, Kim JH. Establishment of a human induced pluripotent stem cell line, KSCBi015-A, from a long QT syndrome type 1 patient harboring a KCNQ1 mutation. Stem Cell Res 2021; 56:102521. [PMID: 34509919 DOI: 10.1016/j.scr.2021.102521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 11/29/2022] Open
Abstract
Long QT syndrome type 1 (LQT1) is a genetic cardiac disorder caused by a loss-of-function mutation in the KCNQ1 gene. In this study, we generated a human induced stem cell line (KSCBi015-A) from an LQT1 patient with a heterozygous mutation located in the KCNQ1 gene, c.569G > A. The KSCBi015-A cell line showed the maintenance of stem cell-like morphology, normal karyotype, and pluripotency, and could differentiate into three germ layers in vitro.
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Affiliation(s)
- Youngsun Lee
- Division of Intractable Diseases Research, Department of Chronic Diseases Convergence Research, Korea National Institute of Health, Osong Health Technology, Administration Complex 202, South Korea; Korea National Stem Cell Bank, South Korea
| | - Hyeyeon Park
- Division of Intractable Diseases Research, Department of Chronic Diseases Convergence Research, Korea National Institute of Health, Osong Health Technology, Administration Complex 202, South Korea; Korea National Stem Cell Bank, South Korea
| | - Soo Kyung Koo
- Division of Intractable Diseases Research, Department of Chronic Diseases Convergence Research, Korea National Institute of Health, Osong Health Technology, Administration Complex 202, South Korea; Korea National Stem Cell Bank, South Korea
| | - Jung-Hyun Kim
- Division of Intractable Diseases Research, Department of Chronic Diseases Convergence Research, Korea National Institute of Health, Osong Health Technology, Administration Complex 202, South Korea; Korea National Stem Cell Bank, South Korea.
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Dienes C, Hézső T, Kiss DZ, Baranyai D, Kovács ZM, Szabó L, Magyar J, Bányász T, Nánási PP, Horváth B, Gönczi M, Szentandrássy N. Electrophysiological Effects of the Transient Receptor Potential Melastatin 4 Channel Inhibitor (4-Chloro-2-(2-chlorophenoxy)acetamido) Benzoic Acid (CBA) in Canine Left Ventricular Cardiomyocytes. Int J Mol Sci 2021; 22:ijms22179499. [PMID: 34502410 PMCID: PMC8430982 DOI: 10.3390/ijms22179499] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/23/2021] [Accepted: 08/27/2021] [Indexed: 01/16/2023] Open
Abstract
Transient receptor potential melastatin 4 (TRPM4) plays an important role in many tissues, including pacemaker and conductive tissues of the heart, but much less is known about its electrophysiological role in ventricular myocytes. Our earlier results showed the lack of selectivity of 9-phenanthrol, so CBA ((4-chloro-2-(2-chlorophenoxy)acetamido) benzoic acid) was chosen as a new, potentially selective inhibitor. Goal: Our aim was to elucidate the effect and selectivity of CBA in canine left ventricular cardiomyocytes and to study the expression of TRPM4 in the canine heart. Experiments were carried out in enzymatically isolated canine left ventricular cardiomyocytes. Ionic currents were recorded with an action potential (AP) voltage-clamp technique in whole-cell configuration at 37 °C. An amount of 10 mM BAPTA was used in the pipette solution to exclude the potential activation of TRPM4 channels. AP was recorded with conventional sharp microelectrodes. CBA was used in 10 µM concentrations. Expression of TRPM4 protein in the heart was studied by Western blot. TRPM4 protein was expressed in the wall of all four chambers of the canine heart as well as in samples prepared from isolated left ventricular cells. CBA induced an approximately 9% reduction in AP duration measured at 75% and 90% of repolarization and decreased the short-term variability of APD90. Moreover, AP amplitude was increased and the maximal rates of phase 0 and 1 were reduced by the drug. In AP clamp measurements, CBA-sensitive current contained a short, early outward and mainly a long, inward current. Transient outward potassium current (Ito) and late sodium current (INa,L) were reduced by approximately 20% and 47%, respectively, in the presence of CBA, while L-type calcium and inward rectifier potassium currents were not affected. These effects of CBA were largely reversible upon washout. Based on our results, the CBA induced reduction of phase-1 slope and the slight increase of AP amplitude could have been due to the inhibition of Ito. The tendency for AP shortening can be explained by the inhibition of inward currents seen in AP-clamp recordings during the plateau phase. This inward current reduced by CBA is possibly INa,L, therefore, CBA is not entirely selective for TRPM4 channels. As a consequence, similarly to 9-phenanthrol, it cannot be used to test the contribution of TRPM4 channels to cardiac electrophysiology in ventricular cells, or at least caution must be applied.
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Affiliation(s)
- Csaba Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Tamás Hézső
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Dénes Zsolt Kiss
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Dóra Baranyai
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Zsigmond Máté Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - László Szabó
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
| | - Péter P. Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary
| | - Mónika Gönczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (C.D.); (T.H.); (D.Z.K.); (D.B.); (Z.M.K.); (L.S.); (J.M.); (T.B.); (P.P.N.); (B.H.); (M.G.)
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
- Correspondence: ; Tel.: +36-52255575; Fax: +36-52255116
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12
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Uzelac I, Kaboudian A, Iravanian S, Siles-Paredes JG, Gumbart JC, Ashikaga H, Bhatia N, Gilmour RF, Cherry EM, Fenton FH. Quantifying arrhythmic long QT effects of hydroxychloroquine and azithromycin with whole-heart optical mapping and simulations. Heart Rhythm O2 2021; 2:394-404. [PMID: 34430945 PMCID: PMC8369304 DOI: 10.1016/j.hroo.2021.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background In March 2020, hydroxychloroquine (HCQ) alone or combined with azithromycin (AZM) was authorized as a treatment for COVID-19 in many countries. The therapy proved ineffective with long QT and deadly cardiac arrhythmia risks, illustrating challenges to determine the new safety profile of repurposed drugs. Objective To investigate proarrhythmic effects and mechanism of HCQ and AZM (combined and alone) with high doses of HCQ as in the COVID-19 clinical trials. Methods Proarrhythmic effects of HCQ and AZM are quantified using optical mapping with voltage-sensitive dyes in ex vivo Langendorff-perfused guinea pig (GP) hearts and with numerical simulations of a GP Luo-Rudy and a human O’Hara-Virag-Varro-Rudy models, for Epi, Endo, and M cells, in cell and tissue, incorporating the drug’s effect on cell membrane ionic currents. Results Experimentally, HCQ alone and combined with AZM leads to long QT intervals by prolonging the action potential duration and increased spatial dispersion of action potential (AP) repolarization across the heart, leading to proarrhythmic discordant alternans. AZM alone had a lesser arrhythmic effect with less triangulation of the AP shape. Mathematical cardiac models fail to reproduce most of the arrhythmic effects observed experimentally. Conclusions During public health crises, the risks and benefits of new and repurposed drugs could be better assessed with alternative experimental and computational approaches to identify proarrhythmic mechanisms. Optical mapping is an effective framework suitable to investigate the drug’s adverse effects on cardiac cell membrane ionic channels at the cellular level and arrhythmia mechanisms at the tissue and whole-organ level.
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Affiliation(s)
- Ilija Uzelac
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Abouzar Kaboudian
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Shahriar Iravanian
- Division of Cardiology, Section of Electrophysiology, Emory University Hospital, Atlanta, Georgia
| | | | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Hiroshi Ashikaga
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Neal Bhatia
- Division of Cardiology, Section of Electrophysiology, Emory University Hospital, Atlanta, Georgia
| | - Robert F Gilmour
- Biomedical Sciences, University of Prince Edward Island, Charlottetown, Canada
| | - Elizabeth M Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Flavio H Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
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13
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Filatova TS, Abramochkin DV, Pavlova NS, Pustovit KB, Konovalova OP, Kuzmin VS, Dobrzynski H. Repolarizing potassium currents in working myocardium of Japanese quail: a novel translational model for cardiac electrophysiology. Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110919. [DOI: 10.1016/j.cbpa.2021.110919] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/06/2021] [Accepted: 02/06/2021] [Indexed: 12/14/2022]
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14
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Ozturk N, Uslu S, Ozdemir S. Diabetes-induced changes in cardiac voltage-gated ion channels. World J Diabetes 2021; 12:1-18. [PMID: 33520105 PMCID: PMC7807254 DOI: 10.4239/wjd.v12.i1.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus affects the heart through various mechanisms such as microvascular defects, metabolic abnormalities, autonomic dysfunction and incompatible immune response. Furthermore, it can also cause functional and structural changes in the myocardium by a disease known as diabetic cardiomyopathy (DCM) in the absence of coronary artery disease. As DCM progresses it causes electrical remodeling of the heart, left ventricular dysfunction and heart failure. Electrophysiological changes in the diabetic heart contribute significantly to the incidence of arrhythmias and sudden cardiac death in diabetes mellitus patients. In recent studies, significant changes in repolarizing K+ currents, Na+ currents and L-type Ca2+ currents along with impaired Ca2+ homeostasis and defective contractile function have been identified in the diabetic heart. In addition, insulin levels and other trophic factors change significantly to maintain the ionic channel expression in diabetic patients. There are many diagnostic tools and management options for DCM, but it is difficult to detect its development and to effectively prevent its progress. In this review, diabetes-associated alterations in voltage-sensitive cardiac ion channels are comprehensively assessed to understand their potential role in the pathophysiology and pathogenesis of DCM.
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Affiliation(s)
- Nihal Ozturk
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Serkan Uslu
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Semir Ozdemir
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
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15
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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16
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Zhang H, Zhang S, Wang W, Wang K, Shen W. A Mathematical Model of the Mouse Atrial Myocyte With Inter-Atrial Electrophysiological Heterogeneity. Front Physiol 2020; 11:972. [PMID: 32848887 PMCID: PMC7425199 DOI: 10.3389/fphys.2020.00972] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/16/2020] [Indexed: 12/20/2022] Open
Abstract
Biophysically detailed mathematical models of cardiac electrophysiology provide an alternative to experimental approaches for investigating possible ionic mechanisms underlying the genesis of electrical action potentials and their propagation through the heart. The aim of this study was to develop a biophysically detailed mathematical model of the action potentials of mouse atrial myocytes, a popular experimental model for elucidating molecular and cellular mechanisms of arrhythmogenesis. Based on experimental data from isolated mouse atrial cardiomyocytes, a set of mathematical equations for describing the biophysical properties of membrane ion channel currents, intracellular Ca2+ handling, and Ca2+-calmodulin activated protein kinase II and β-adrenergic signaling pathways were developed. Wherever possible, membrane ion channel currents were modeled using Markov chain formalisms, allowing detailed representation of channel kinetics. The model also considered heterogeneous electrophysiological properties between the left and the right atrial cardiomyocytes. The developed model was validated by its ability to reproduce the characteristics of action potentials and Ca2+ transients, matching quantitatively to experimental data. Using the model, the functional roles of four K+ channel currents in atrial action potential were evaluated by channel block simulations, results of which were quantitatively in agreement with existent experimental data. To conclude, this newly developed model of mouse atrial cardiomyocytes provides a powerful tool for investigating possible ion channel mechanisms of atrial electrical activity at the cellular level and can be further used to investigate mechanisms underlying atrial arrhythmogenesis.
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Affiliation(s)
- Henggui Zhang
- Department of Physics and Astronomy, Biological Physics Group, School of Physics & Astronomy, The University of Manchester, Manchester, United Kingdom.,Peng Cheng Laboratory, Shenzhen, China
| | - Shanzhuo Zhang
- Department of Physics and Astronomy, Biological Physics Group, School of Physics & Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Wei Wang
- Department of Physics and Astronomy, Biological Physics Group, School of Physics & Astronomy, The University of Manchester, Manchester, United Kingdom.,Peng Cheng Laboratory, Shenzhen, China.,Shenzhen Key Laboratory of Visual Object Detection and Recognition, Harbin Institute of Technology, Shenzhen, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Weijian Shen
- Department of Physics and Astronomy, Biological Physics Group, School of Physics & Astronomy, The University of Manchester, Manchester, United Kingdom
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17
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Shi M, Tien NT, de Haan L, Louisse J, Rietjens IMCM, Bouwmeester H. Evaluation of in vitro models of stem cell-derived cardiomyocytes to screen for potential cardiotoxicity of chemicals. Toxicol In Vitro 2020; 67:104891. [PMID: 32446838 DOI: 10.1016/j.tiv.2020.104891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/14/2020] [Accepted: 05/16/2020] [Indexed: 12/12/2022]
Abstract
Cardiotoxicity is an important toxicological endpoint for chemical and drug safety assessment. The present study aims to evaluate two stemcell-based in vitro models for cardiotoxicity screening of chemicals. Eleven model compounds were used to evaluate responses of mouse embryonic stem cell-derived cardiomyocytes (mESC-CMs) using beating arrest as a readout and the analysis of electrophysiological parameters measured with a multi-electrode array (MEA) platform of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Results revealed that the hiPSC-CM MEA assay responded to all compounds. The mESC-CM beating arrest assay was not responsive to potassium channel blockers and showed a lower sensitivity to sodium channel blockers and Na+/K+ ATPase inhibitors compared to the hiPSC-CM MEA assay. Calcium channel blockers and a β-adrenergic receptor agonist showed comparable potencies in both models. The in vitro response concentrations from hiPSC-CMs were highly concordant with human effective serum concentrations of potassium and sodium channel blockers. It is concluded that both in vitro models enable the cardiotoxicity screening with different applicability domains. The mESC-CM beating arrest assay may be used as a first step in a tiered approach while the hiPSC-CM MEA assay may be the best starting point for quantitative in vitro to in vivo extrapolations.
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Affiliation(s)
- Miaoying Shi
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Nguyen T Tien
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands
| | - Laura de Haan
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Jochem Louisse
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Hans Bouwmeester
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
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18
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Fusi F, Trezza A, Tramaglino M, Sgaragli G, Saponara S, Spiga O. The beneficial health effects of flavonoids on the cardiovascular system: Focus on K+ channels. Pharmacol Res 2020; 152:104625. [DOI: 10.1016/j.phrs.2019.104625] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/14/2019] [Accepted: 12/31/2019] [Indexed: 01/17/2023]
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19
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Abstract
Computational modeling based on experimental data remains an important component in cardiac electrophysiological research, especially because clinical data such as human action potential (AP) dynamics are scarce or limited by practical or ethical concerns. Such modeling has been used to develop and test a variety of mechanistic hypotheses, with the majority of these studies involving the rate dependence of AP duration (APD) including APD restitution and conduction velocity (CV). However, there is very little information regarding the complex dynamics at the boundary of repolarization (or refractoriness) and reexcitability. Here, we developed a "minimal" ionic model of the human AP, based on in vivo human monophasic AP (MAP) recordings obtained during clinical programmed electrical stimulation (PES) to address the progressive decrease in AP take-off potential (TOP) and associated CV slowing seen during three tightly spaced extrastimuli. Recent voltage-clamp data demonstrating the effect of intracellular calcium on sodium current availability were incorporated and were required to reproduce large (>15 mV) elevations in take-off potential and progressive encroachment. Introducing clinically observed APD gradients into the model enabled us to replicate the dynamic response to PES in patients leading to conduction block and reentry formation for the positive, but not the negative, APD gradient. Finally, we modeled the dynamics of reentry and show that spiral waves follow a meandering trajectory with a period of ~180 ms. We conclude that our model reproduces a variety of electrophysiological behavior including the response to sequential premature stimuli and provides a basis for studies of the initiation of reentry in human ventricular tissue.NEW & NOTEWORTHY This work presents a new model of the action potential of the human which reproduces the complex dynamics during premature stimulation in patients.
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Affiliation(s)
- Richard A Gray
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland
| | - Michael R Franz
- Cardiology Division of Cardiology, Veteran Affairs Medical Center, Washington, District of Columbia.,Department of Pharmacology, Georgetown University Medical Center, Washington, District of Columbia
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20
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Abramochkin DV, Matchkov V, Wang T. A characterization of the electrophysiological properties of the cardiomyocytes from ventricle, atrium and sinus venosus of the snake heart. J Comp Physiol B 2019; 190:63-73. [DOI: 10.1007/s00360-019-01253-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/15/2019] [Accepted: 12/08/2019] [Indexed: 12/21/2022]
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21
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Abi-Gerges N, Miller PE, Ghetti A. Human Heart Cardiomyocytes in Drug Discovery and Research: New Opportunities in Translational Sciences. Curr Pharm Biotechnol 2019; 21:787-806. [PMID: 31820682 DOI: 10.2174/1389201021666191210142023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/14/2019] [Accepted: 10/28/2019] [Indexed: 12/28/2022]
Abstract
In preclinical drug development, accurate prediction of drug effects on the human heart is critically important, whether in the context of cardiovascular safety or for the purpose of modulating cardiac function to treat heart disease. Current strategies have significant limitations, whereby, cardiotoxic drugs can escape detection or potential life-saving therapies are abandoned due to false positive toxicity signals. Thus, new and more reliable translational approaches are urgently needed to help accelerate the rate of new therapy development. Renewed efforts in the recovery of human donor hearts for research and in cardiomyocyte isolation methods, are providing new opportunities for preclinical studies in adult primary cardiomyocytes. These cells exhibit the native physiological and pharmacological properties, overcoming the limitations presented by artificial cellular models, animal models and have great potential for providing an excellent tool for preclinical drug testing. Adult human primary cardiomyocytes have already shown utility in assessing drug-induced cardiotoxicity risk and helping in the identification of new treatments for cardiac diseases, such as heart failure and atrial fibrillation. Finally, strategies with actionable decision-making trees that rely on data derived from adult human primary cardiomyocytes will provide the holistic insights necessary to accurately predict human heart effects of drugs.
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Affiliation(s)
- Najah Abi-Gerges
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
| | - Paul E Miller
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
| | - Andre Ghetti
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
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22
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Zhang Y, Du W, Yang B. Long non-coding RNAs as new regulators of cardiac electrophysiology and arrhythmias: Molecular mechanisms, therapeutic implications and challenges. Pharmacol Ther 2019; 203:107389. [DOI: 10.1016/j.pharmthera.2019.06.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/27/2019] [Indexed: 12/21/2022]
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23
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Wang Y, Zhu R, Tung L. Contribution of potassium channels to action potential repolarization of human embryonic stem cell-derived cardiomyocytes. Br J Pharmacol 2019; 176:2780-2794. [PMID: 31074016 DOI: 10.1111/bph.14704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 03/11/2019] [Accepted: 03/29/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE The electrophysiological properties of human pluripotent stem cell-derived cardiomyocytes (CMs) have not yet been characterized in a syncytial context. This study systematically characterized the contributions of different repolarizing potassium currents in human embryonic stem cell-derived CMs (hESC-CMs) during long-term culture as cell monolayers. EXPERIMENTAL APPROACH The H9 hESC line was differentiated to CMs and plated to form confluent cell monolayers. Optical mapping was used to record the action potentials (APs) and conduction velocity (CV) during electrophysiological and pharmacological experiments. RT-PCR and Western blot were used to detect the presence and expression levels of ion channel subunits. KEY RESULTS Long-term culture of hESC-CMs led to shortened AP duration (APD), faster repolarization rate, and increased CV. Selective block of IKr , IKs , IK1 , and IKur significantly affected AP repolarization and APD in a concentration- and culture time-dependent manner. Baseline variations in APD led to either positive or negative APD dependence of drug response. Chromanol 293B produced greater relative AP prolongation in mid- and late-stage cultures, while DPO-1 had more effect in early-stage cultures. CV in cell monolayers in early- and late-stage cultures was most susceptible to slowing by E-4031 and BaCl2 respectively. CONCLUSIONS AND IMPLICATIONS IKr , IKs , IK1 , and IKur all play an essential role in the regulation of APD and CV in hESC-CMs. During time in culture, increased expression of IKr and IK1 helps to accelerate repolarization, shorten APD, and increase CV. We identified a new pro-arrhythmic parameter, positive APD dependence of ion channel block, which can increase APD and repolarization gradients.
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Affiliation(s)
- Yin Wang
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, USA.,Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Renjun Zhu
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Leslie Tung
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, USA
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24
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Osadchii OE. Effects of antiarrhythmics on the electrical restitution in perfused guinea-pig heart are critically determined by the applied cardiac pacing protocol. Exp Physiol 2019; 104:490-504. [PMID: 30758086 DOI: 10.1113/ep087531] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/12/2019] [Indexed: 01/11/2023]
Abstract
NEW FINDINGS What is the central question of this study? Are modifications in the restitution of ventricular action potential duration induced by antiarrhythmic drugs the same when assessed with premature extrastimulus application at variable coupling intervals (the standard stimulation protocol) and with steady state pacing at variable rates (the dynamic stimulation protocol)? What is the main finding and its importance? With class I and class III antiarrhythmics, the effects on electrical restitution determined with the standard stimulation protocol dissociate from those obtained during dynamic pacing. These findings indicate a limited value of the electrical restitution assessments based on extrasystolic stimulations alone, as performed in the clinical studies, in estimating the outcomes of antiarrhythmic drug therapies. ABSTRACT A steep slope of the ventricular action potential duration (APD) to diastolic interval (DI) relationships (the electrical restitution) can precipitate tachyarrhythmia, whereas a flattened slope is antiarrhythmic. The derangements in APD restitution responsible for transition of tachycardia to ventricular fibrillation can be assessed with cardiac pacing at progressively increasing rates (the dynamic stimulation protocol). Nevertheless, this method is not used clinically owing to the risk of inducing myocardial ischaemia. Instead, the restitution kinetics is determined with a premature extrastimulus application at variable coupling intervals (the standard stimulation protocol). Whether the two protocols are equivalent in estimating antiarrhythmic drug effects is uncertain. In this study, dofetilide and quinidine, the agents blocking repolarizing K+ currents, increased epicardial APD in perfused guinea-pig hearts, with effects being greater at long vs. short DIs. These changes were more pronounced during dynamic pacing compared to premature extrastimulations. Accordingly, although both agents markedly steepened the dynamic restitution, there was only a marginal increase in the standard restitution slope with dofetilide, and no effect with quinidine. Lidocaine and mexiletine, selective Na+ channel blockers, prolonged the effective refractory period without changing APD, and increased the minimum DI that enabled ventricular capture during extrastimulations. No change in the minimum DI was noted during dynamic pacing. Consequently, although lidocaine and mexiletine reduced the standard restitution slope, they failed to flatten the dynamic restitution. Overall, these findings imply a limited value of the electrical restitution assessments with premature extrastimulations alone in discriminating arrhythmic vs. antiarrhythmic changes during drug therapies.
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Affiliation(s)
- Oleg E Osadchii
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.,Department of Health Science and Technology, University of Aalborg, Fredrik Bajers Vej 7E, 9220, Aalborg, Denmark
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25
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Bohannon BM, Perez ME, Liin SI, Larsson HP. ω-6 and ω-9 polyunsaturated fatty acids with double bonds near the carboxyl head have the highest affinity and largest effects on the cardiac I K s potassium channel. Acta Physiol (Oxf) 2019; 225:e13186. [PMID: 30184322 PMCID: PMC6335172 DOI: 10.1111/apha.13186] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/30/2018] [Accepted: 09/02/2018] [Indexed: 02/06/2023]
Abstract
Aim The IKs channel is important for termination of the cardiac action potential. Hundreds of loss‐of‐function mutations in the IKs channel reduce the K+ current and, thereby, delay the repolarization of the action potential, causing Long QT Syndrome. Long QT predisposes individuals to Torsades de Pointes which can lead to ventricular fibrillation and sudden death. Polyunsaturated fatty acids (PUFAs) are potential therapeutics for Long QT Syndrome, as they affect IKs channels. However, it is unclear which properties of PUFAs are essential for their effects on IKs channels. Methods To understand how PUFAs influence IKs channel activity, we measured effects on IKs current by two‐electrode voltage clamp while changing different properties of the hydrocarbon tail. Results There was no, or weak, correlation between the tail length or number of double bonds in the tail and the effects on or apparent binding affinity for IKs channels. However, we found a strong correlation between the positions of the double bonds relative to the head group and effects on IKs channels. Conclusion Polyunsaturated fatty acids with double bonds closer to the head group had higher apparent affinity for IKs channels and increased IKs current more; shifting the bonds further away from the head group reduced apparent binding affinity for and effects on the IKs current. Interestingly, we found that ω‐6 and ω‐9 PUFAs, with the first double bond closer to the head group, left‐shifted the voltage dependence of activation the most. These results allow for informed design of new therapeutics targeting IKs channels in Long QT Syndrome.
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Affiliation(s)
- Briana M. Bohannon
- Department of Physiology and Biophysics; Miller School of Medicine; University of Miami; Miami Florida
| | - Marta E. Perez
- Department of Physiology and Biophysics; Miller School of Medicine; University of Miami; Miami Florida
| | - Sara I. Liin
- Department of Clinical and Experimental Medicine; Linköping University; Linköping Sweden
| | - Hans Peter Larsson
- Department of Physiology and Biophysics; Miller School of Medicine; University of Miami; Miami Florida
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Hodgson P, Ireland J, Grunow B. Fish, the better model in human heart research? Zebrafish Heart aggregates as a 3D spontaneously cardiomyogenic in vitro model system. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:132-141. [PMID: 29729327 DOI: 10.1016/j.pbiomolbio.2018.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/04/2018] [Accepted: 04/27/2018] [Indexed: 12/25/2022]
Abstract
The zebrafish (ZF) has become an essential model for biomedical, pharmacological and eco-toxicological heart research. Despite the anatomical differences between fish and human hearts, similarities in cellular structure and conservation of genes as well as pathways across vertebrates have led to an increase in the popularity of ZF as a model for human cardiac research. ZF research benefits from an entirely sequenced genome, which allows us to establish and study cardiovascular mutants to better understand cardiovascular diseases. In this review, we will discuss the importance of in vitro model systems for cardiac research and summarise results of in vitro 3D heart-like cell aggregates, consisting of myocardial tissue formed spontaneously from enzymatically digested whole embryonic ZF larvae (Zebrafish Heart Aggregate - ZFHA). We will give an overview of the similarities and differences of ZF versus human hearts and highlight why ZF complement established mammalian models (i.e. murine and large animal models) for cardiac research. At this stage, the ZFHA model system is being refined into a high-throughput (more ZFHA generated than larvae prepared) and stable in vitro test system to accomplish the same longevity of previously successful salmonid models. ZFHA have potential for the use of high-throughput-screenings of different factors like small molecules, nucleic acids, proteins and lipids which is difficult to achieve in the zebrafish in vivo screening models with lethal mutations as well as to explore ion channel disorders and to find appropriate drugs for safety screening.
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Affiliation(s)
- Patricia Hodgson
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK; Salford Royal NHS Foundation Trust, Stott Lane, Salford M6 8HD, UK
| | - Jake Ireland
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK; School of Chemistry, Materials Science, and Engineering, Hilmer Building, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Bianka Grunow
- University Medicine Greifswald, Institute of Physiology, Greifswalder Str. 11C, 17495 Karlsburg, Germany; Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK.
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Perissinotti LL, De Biase PM, Guo J, Yang PC, Lee MC, Clancy CE, Duff HJ, Noskov SY. Determinants of Isoform-Specific Gating Kinetics of hERG1 Channel: Combined Experimental and Simulation Study. Front Physiol 2018; 9:207. [PMID: 29706893 PMCID: PMC5907531 DOI: 10.3389/fphys.2018.00207] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/23/2018] [Indexed: 12/22/2022] Open
Abstract
IKr is the rapidly activating component of the delayed rectifier potassium current, the ion current largely responsible for the repolarization of the cardiac action potential. Inherited forms of long QT syndrome (LQTS) (Lees-Miller et al., 1997) in humans are linked to functional modifications in the Kv11.1 (hERG) ion channel and potentially life threatening arrhythmias. There is little doubt now that hERG-related component of IKr in the heart depends on the tetrameric (homo- or hetero-) channels formed by two alternatively processed isoforms of hERG, termed hERG1a and hERG1b. Isoform composition (hERG1a- vs. the b-isoform) has recently been reported to alter pharmacologic responses to some hERG blockers and was proposed to be an essential factor pre-disposing patients for drug-induced QT prolongation. Very little is known about the gating and pharmacological properties of two isoforms in heart membranes. For example, how gating mechanisms of the hERG1a channels differ from that of hERG1b is still unknown. The mechanisms by which hERG 1a/1b hetero-tetramers contribute to function in the heart, or what role hERG1b might play in disease are all questions to be answered. Structurally, the two isoforms differ only in the N-terminal region located in the cytoplasm: hERG1b is 340 residues shorter than hERG1a and the initial 36 residues of hERG1b are unique to this isoform. In this study, we combined electrophysiological measurements for HEK cells, kinetics and structural modeling to tease out the individual contributions of each isoform to Action Potential formation and then make predictions about the effects of having various mixture ratios of the two isoforms. By coupling electrophysiological data with computational kinetic modeling, two proposed mechanisms of hERG gating in two homo-tetramers were examined. Sets of data from various experimental stimulation protocols (HEK cells) were analyzed simultaneously and fitted to Markov-chain models (M-models). The minimization procedure presented here, allowed assessment of suitability of different Markov model topologies and the corresponding parameters that describe the channel kinetics. The kinetics modeling pointed to key differences in the gating kinetics that were linked to the full channel structure. Interactions between soluble domains and the transmembrane part of the channel appeared to be critical determinants of the gating kinetics. The structures of the full channel in the open and closed states were compared for the first time using the recent Cryo-EM resolved structure for full open hERG channel and an homology model for the closed state, based on the highly homolog EAG1 channel. Key potential interactions which emphasize the importance of electrostatic interactions between N-PAS cap, S4-S5, and C-linker are suggested based on the structural analysis. The derived kinetic parameters were later used in higher order models of cells and tissue to track down the effect of varying the ratios of hERG1a and hERG1b on cardiac action potentials and computed electrocardiograms. Simulations suggest that the recovery from inactivation of hERG1b may contribute to its physiologic role of this isoform in the action potential. Finally, the results presented here contribute to the growing body of evidence that hERG1b significantly affects the generation of the cardiac Ikr and plays an important role in cardiac electrophysiology. We highlight the importance of carefully revisiting the Markov models previously proposed in order to properly account for the relative abundance of the hERG1 a- and b- isoforms.
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Affiliation(s)
- Laura L Perissinotti
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Pablo M De Biase
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Miranda C Lee
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Sergei Y Noskov
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
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28
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A double-blind, randomised, placebo-controlled, cross-over study assessing the use of XEN-D0103 in patients with paroxysmal atrial fibrillation and implanted pacemakers allowing continuous beat-to-beat monitoring of drug efficacy. J Interv Card Electrophysiol 2018; 51:191-197. [PMID: 29460236 DOI: 10.1007/s10840-018-0318-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 01/24/2018] [Indexed: 01/21/2023]
Abstract
PURPOSE The ultrarapid delayed rectifier current (IKur) carried by Kv1.5 channels, which are solely expressed in the atrium, is a potential target for safer treatment of paroxysmal atrial fibrillation (PAF). XEN-D0103 is a nanomolar ion channel blocker that selectively inhibits potassium ion flux through the Kv1.5 ion channel. The efficacy of XEN-D0103 in reducing AF burden was assessed in patients with DDDRp permanent pacemakers (PPMs) and PAF. METHODS A double-blind, placebo-controlled, cross-over study was performed in patients with PAF and DDDRp PPMs with advanced atrial and ventricular Holters allowing beat-to-beat arrhythmia follow-up. All anti-arrhythmic drugs were withdrawn before randomised treatment. After baseline assessment, patients were randomly assigned to two treatment periods of placebo then XEN-D0103 50 mg bd, or XEN-D0103 50 mg bd then placebo. RESULTS Fifty-four patients were screened and 21 patients were eligible and included in the randomised trial. All 21 patients completed both treatment periods. The primary endpoint was change in AF burden assessed by PPM. There was no significant difference in AF burden on treatment with XEN-D0103 versus placebo. There was a reduction in the mean frequency of AF episodes (relative reduction 0.72, 95% CI 0.66 to 0.77; p < 0.0001). XEN-D0103 was safe and well tolerated, and there were no serious adverse events. XEN-D0103 did not have any apparent effect on heart rate compared to placebo. CONCLUSIONS XEN-D0103 did not reduce AF burden in patients with PAF and dual chamber pacemakers providing beat-to-beat monitoring. XEN-D0103 was well tolerated and did not have any apparent effect on heart rate. Although single-ion channel blockade with XEN-D0103 did not affect AF in this study, there might be a potential for this agent to be used in combination with other atrially specific drugs in the treatment of AF. EUDRACT TRIAL REGISTRATION NUMBER 2013-004456-38.
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29
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Weinberger F, Breckwoldt K, Pecha S, Kelly A, Geertz B, Starbatty J, Yorgan T, Cheng KH, Lessmann K, Stolen T, Scherrer-Crosbie M, Smith G, Reichenspurner H, Hansen A, Eschenhagen T. Cardiac repair in guinea pigs with human engineered heart tissue from induced pluripotent stem cells. Sci Transl Med 2017; 8:363ra148. [PMID: 27807283 DOI: 10.1126/scitranslmed.aaf8781] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 09/19/2016] [Indexed: 12/16/2022]
Abstract
Myocardial injury results in a loss of contractile tissue mass that, in the absence of efficient regeneration, is essentially irreversible. Transplantation of human pluripotent stem cell-derived cardiomyocytes has beneficial but variable effects. We created human engineered heart tissue (hEHT) strips from human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and hiPSC-derived endothelial cells. The hEHTs were transplanted onto large defects (22% of the left ventricular wall, 35% decline in left ventricular function) of guinea pig hearts 7 days after cryoinjury, and the results were compared with those obtained with human endothelial cell patches (hEETs) or cell-free patches. Twenty-eight days after transplantation, the hearts repaired with hEHT strips exhibited, within the scar, human heart muscle grafts, which had remuscularized 12% of the infarct area. These grafts showed cardiomyocyte proliferation, vascularization, and evidence for electrical coupling to the intact heart tissue in a subset of engrafted hearts. hEHT strips improved left ventricular function by 31% compared to that before implantation, whereas the hEET or cell-free patches had no effect. Together, our study demonstrates that three-dimensional human heart muscle constructs can repair the injured heart.
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Affiliation(s)
- Florian Weinberger
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Kaja Breckwoldt
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Simon Pecha
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany.,Department of Cardiovascular Surgery, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Allen Kelly
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7030 Trondheim, Norway.,Norwegian Council on Cardiovascular Disease, Oslo, Norway
| | - Birgit Geertz
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Jutta Starbatty
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Timur Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Kai-Hung Cheng
- Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Katrin Lessmann
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Tomas Stolen
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7030 Trondheim, Norway.,Norwegian Council on Cardiovascular Disease, Oslo, Norway
| | | | - Godfrey Smith
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7030 Trondheim, Norway.,Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - Hermann Reichenspurner
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany.,Department of Cardiovascular Surgery, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Arne Hansen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany. .,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
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30
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Abramochkin DV, Kuzmin VS, Rosenshtraukh LV. A New Class III Antiarrhythmic Drug Niferidil Prolongs Action Potentials in Guinea Pig Atrial Myocardium via Inhibition of Rapid Delayed Rectifier. Cardiovasc Drugs Ther 2017; 31:525-533. [PMID: 29181609 DOI: 10.1007/s10557-017-6762-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE A new class III antiarrhythmic drug niferidil (RG-2) has been introduced as a highly effective therapy for cases of persistent atrial fibrillation, but ionic mechanisms of its action are poorly understood. In the present study, the effects of niferidil on action potential (AP) waveform and potassium currents responsible for AP repolarization were investigated in guinea pig atrial myocardium. METHODS APs were recorded with sharp glass microelectrodes in multicellular atrial preparations. Whole-cell patch-clamp technique was used to measure K+ currents in isolated myocytes. RESULTS In multicellular atrial preparations, 10-8 M niferidil effectively prolonged APs by 15.2 ± 2.8% at 90% repolarization level. However, even the highest tested concentrations, 10-6 M and 10-5 M failed to prolong APs more than 32.5% of control duration. The estimated concentration of niferedil for half-maximal AP prolongation was 1.13 × 10-8 M. Among the potassium currents responsible for AP repolarization phase, I K1 was found to be almost insensitive to niferidil. However, another inward rectifier, I KACh, was effectively suppressed by micromolar concentrations of niferidil with IC50 = 9.2 × 10-6 M. I KATP was much less sensitive to the drug with IC50 = 2.26 × 10-4 M. The slow component of delayed rectifier, I Ks, also demonstrated low sensitivity to niferidil-the highest used concentration, 10-4 M, decreased peak I Ks density to 46.2 ± 5.5% of control. Unlike I Ks, the rapid component of delayed rectifier, I Kr, appeared to be extremely sensitive to niferidil. The IC50 was 1.26 × 10-9 M. I Kr measured in ventricular myocytes was found to be less sensitive to niferidil with IC50 = 3.82 × 10-8 M. CONCLUSIONS Niferidil prolongs APs in guinea pig atrial myocardium via inhibition of I Kr.
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Affiliation(s)
- Denis V Abramochkin
- Lomonosov Moscow State University, Moscow, Russia. .,Pirogov Russian National Research Medical University, Moscow, Russia. .,Department of Human and Animal Physiology, Moscow State University, Leninskije Gory, 1, 12, Moscow, Russia.
| | - Vladislav S Kuzmin
- Lomonosov Moscow State University, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia.,Institute of Experimental Cardiology, Moscow, Russia
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31
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β-adrenergic stimulation augments transmural dispersion of repolarization via modulation of delayed rectifier currents I Ks and I Kr in the human ventricle. Sci Rep 2017; 7:15922. [PMID: 29162896 PMCID: PMC5698468 DOI: 10.1038/s41598-017-16218-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022] Open
Abstract
Long QT syndrome (LQTS) is an inherited or drug induced condition associated with delayed repolarization and sudden cardiac death. The cardiac potassium channel, IKr, and the adrenergic-sensitive cardiac potassium current, IKs, are two primary contributors to cardiac repolarization. This study aimed to elucidate the role of β-adrenergic (β-AR) stimulation in mediating the contributions of IKr and IKs to repolarizing the human left ventricle (n = 18). Optical mapping was used to measure action potential durations (APDs) in the presence of the IKs blocker JNJ-303 and the IKr blocker E-4031. We found that JNJ-303 alone did not increase APD. However, under isoprenaline (ISO), both the application of JNJ-303 and additional E-4031 significantly increased APD. With JNJ-303, ISO decreased APD significantly more in the epicardium as compared to the endocardium, with subsequent application E-4031 increasing mid- and endocardial APD80 more significantly than in the epicardium. We found that β-AR stimulation significantly augmented the effect of IKs blocker JNJ-303, in contrast to the reduced effect of IKr blocker E-4031. We also observed synergistic augmentation of transmural repolarization gradient by the combination of ISO and E-4031. Our results suggest β-AR-mediated increase of transmural dispersion of repolarization, which could pose arrhythmogenic risk in LQTS patients.
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32
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Sahu ID, Craig AF, Dunagum MM, McCarrick RM, Lorigan GA. Characterization of Bifunctional Spin Labels for Investigating the Structural and Dynamic Properties of Membrane Proteins Using EPR Spectroscopy. J Phys Chem B 2017; 121:9185-9195. [PMID: 28877443 DOI: 10.1021/acs.jpcb.7b07631] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Site-directed spin labeling (SDSL) coupled with electron paramagnetic resonance (EPR) spectroscopy is a very powerful technique to study structural and dynamic properties of membrane proteins. The most widely used spin label is methanthiosulfonate (MTSL). However, the flexibility of this spin label introduces greater uncertainties in EPR measurements obtained for determining structures, side-chain dynamics, and backbone motion of membrane protein systems. Recently, a newer bifunctional spin label (BSL), 3,4-bis(methanethiosulfonylmethyl)-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yloxy, has been introduced to overcome the dynamic limitations associated with the MTSL spin label and has been invaluable in determining protein backbone dynamics and inter-residue distances due to its restricted internal motion and fewer size restrictions. While BSL has been successful in providing more accurate information about the structure and dynamics of several proteins, a detailed characterization of the spin label is still lacking. In this study, we characterized BSLs by performing CW-EPR spectral line shape analysis as a function of temperature on spin-labeled sites inside and outside of the membrane for the integral membrane protein KCNE1 in POPC/POPG lipid bilayers and POPC/POPG lipodisq nanoparticles. The experimental data revealed a powder pattern spectral line shape for all of the KCNE1-BSL samples at 296 K, suggesting the motion of BSLs approaches the rigid limit regime for these series of samples. BSLs were further utilized to report for the first time the distance measurement between two BSLs attached on an integral membrane protein KCNE1 in POPC/POPG lipid bilayers at room temperature using dipolar line broadening CW-EPR spectroscopy. The CW dipolar line broadening EPR data revealed a 15 ± 2 Å distance between doubly attached BSLs on KCNE1 (53/57-63/67) which is consistent with molecular dynamics modeling and the solution NMR structure of KCNE1 which yielded a distance of 17 Å. This study demonstrates the utility of investigating the structural and dynamic properties of membrane proteins in physiologically relevant membrane mimetics using BSLs.
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Affiliation(s)
- Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Andrew F Craig
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Megan M Dunagum
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert M McCarrick
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
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Jeevaratnam K, Chadda KR, Huang CLH, Camm AJ. Cardiac Potassium Channels: Physiological Insights for Targeted Therapy. J Cardiovasc Pharmacol Ther 2017; 23:119-129. [PMID: 28946759 PMCID: PMC5808825 DOI: 10.1177/1074248417729880] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development of novel drugs specifically directed at the ion channels underlying particular features of cardiac action potential (AP) initiation, recovery, and refractoriness would contribute to an optimized approach to antiarrhythmic therapy that minimizes potential cardiac and extracardiac toxicity. Of these, K+ channels contribute numerous and diverse currents with specific actions on different phases in the time course of AP repolarization. These features and their site-specific distribution make particular K+ channel types attractive therapeutic targets for the development of pharmacological agents attempting antiarrhythmic therapy in conditions such as atrial fibrillation. However, progress in the development of such temporally and spatially selective antiarrhythmic drugs against particular ion channels has been relatively limited, particularly in view of our incomplete understanding of the complex physiological roles and interactions of the various ionic currents. This review summarizes the physiological properties of the main cardiac potassium channels and the way in which they modulate cardiac electrical activity and then critiques a number of available potential antiarrhythmic drugs directed at them.
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Affiliation(s)
- Kamalan Jeevaratnam
- 1 Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,2 School of Medicine, Perdana University-Royal College of Surgeons Ireland, Serdang, Selangor Darul Ehsan, Malaysia
| | - Karan R Chadda
- 1 Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,3 Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Christopher L-H Huang
- 3 Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,4 Division of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - A John Camm
- 5 Cardiac Clinical Academic Group, St George's Hospital Medical School, University of London, Cranmer Terrace, London, United Kingdom
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34
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Effects of equol on multiple K+ channels stably expressed in HEK 293 cells. PLoS One 2017; 12:e0183708. [PMID: 28832658 PMCID: PMC5568406 DOI: 10.1371/journal.pone.0183708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022] Open
Abstract
The present study investigated the effects of equol on cardiovascular K+ channel currents. The cardiovascular K+ channel currents were determined in HEK 293 cells stably expressing cloned differential cardiovascular K+ channels with conventional whole-cell patch voltage-clamp technique. We found that equol inhibited hKv1.5 (IC50: 15.3 μM), hKv4.3 (IC50: 29.2 μM and 11.9 μM for hKv4.3 peak current and charge area, respectively), IKs (IC50: 24.7 μM) and IhERG (IC50: 31.6 and 56.5 μM for IhERG.tail and IhERG.step, respectively), but not hKir2.1 current, in a concentration-dependent manner. Interestingly, equol increased BKCa current with an EC50 of 0.1 μM. It had no significant effect on guinea pig ventricular action potentials at concentrations of ≤3 μM. These results demonstrate that equol inhibits several cardiac K+ currents at relatively high concentrations, whereas it increases BKCa current at very low concentrations, suggesting that equol is a safe drug candidate for treating patients with cerebral vascular disorders.
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35
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Osadchii OE. Role of abnormal repolarization in the mechanism of cardiac arrhythmia. Acta Physiol (Oxf) 2017; 220 Suppl 712:1-71. [PMID: 28707396 DOI: 10.1111/apha.12902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K+ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca2+ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na+ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K+ channel (dofetilide).
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Affiliation(s)
- O. E. Osadchii
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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36
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Sahu ID, Zhang R, Dunagan MM, Craig AF, Lorigan GA. Characterization of KCNE1 inside Lipodisq Nanoparticles for EPR Spectroscopic Studies of Membrane Proteins. J Phys Chem B 2017; 121:5312-5321. [DOI: 10.1021/acs.jpcb.7b01705] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Indra D. Sahu
- Department of Chemistry and
Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Rongfu Zhang
- Department of Chemistry and
Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Megan M. Dunagan
- Department of Chemistry and
Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Andrew F. Craig
- Department of Chemistry and
Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Gary A. Lorigan
- Department of Chemistry and
Biochemistry, Miami University, Oxford, Ohio 45056, United States
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37
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Cao F, Wang T, Ding W, Li Z, Shi S, Wang X. Effects of diacetyl-liensinine on electrophysiology in rabbit ventricular myocytes. BMC Pharmacol Toxicol 2017; 18:33. [PMID: 28476169 PMCID: PMC5420095 DOI: 10.1186/s40360-017-0137-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 04/27/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Diacetyl-liensinine is a chemosynthetic derivative of liensinine, extracted from the seed embryo of Nelumbo nucifera Gaertn, in China. It has been found to have extensive anti- arrhythmic actions. The present study was designed to investigate the effects of diacetyl-liensinine on electro- physiology of myocytes. METHODS We exposed rabbit ventricular myocytes to diacetyl-liensinine using standard whole-cell patch-clamp technique and measured the action potential, L-type calcium current (I Ca-L), delayed rectifier potassium current (I K), transient outward potassium current (I to) and inward rectifier potassium current (I K1). RESULTS Our results showed that diacetyl-liensinine significantly prolonged action potential duration at 50 and 90% repolarization (APD50, APD90), at 10 and 30 μM, while shortened APD50 and APD90 at 100 μM. In addition, diacetyl-liensinine inhibited the ICa-L, IK, I to and IK1 in a concentration-dependent manner. CONCLUSIONS The results suggest that diacetyl-liensinine might be a potential anti-arrhythmic agent.
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Affiliation(s)
- Feng Cao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, People's Republic of China.
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, People's Republic of China.
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, People's Republic of China.
| | - Teng Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, People's Republic of China
| | - Wenmao Ding
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, People's Republic of China
| | - Zhe Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, People's Republic of China
| | - Shaobo Shi
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, People's Republic of China
| | - Xiaozhan Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, People's Republic of China
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Gunaga P, Lloyd J, Mummadi S, Banerjee A, Dhondi NK, Hennan J, Subray V, Jayaram R, Rajugowda N, Umamaheshwar Reddy K, Kumaraguru D, Mandal U, Beldona D, Adisechen AK, Yadav N, Warrier J, Johnson JA, Sale H, Putlur SP, Saxena A, Chimalakonda A, Mandlekar S, Conder M, Xing D, Gupta AK, Gupta A, Rampulla R, Mathur A, Levesque P, Wexler RR, Finlay HJ. Selective I Kur Inhibitors for the Potential Treatment of Atrial Fibrillation: Optimization of the Phenyl Quinazoline Series Leading to Clinical Candidate 5-[5-Phenyl-4-(pyridin-2-ylmethylamino)quinazolin-2-yl]pyridine-3-sulfonamide. J Med Chem 2017; 60:3795-3803. [PMID: 28418664 DOI: 10.1021/acs.jmedchem.6b01889] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have recently disclosed 5-phenyl-N-(pyridin-2-ylmethyl)-2-(pyrimidin-5-yl)quinazolin-4-amine 1 as a potent IKur current blocker with selectivity versus hERG, Na and Ca channels, and an acceptable preclinical PK profile. Upon further characterization in vivo, compound 1 demonstrated an unacceptable level of brain penetration. In an effort to reduce the level of brain penetration while maintaining the overall profile, SAR was developed at the C2' position for a series of close analogues by employing hydrogen bond donors. As a result, 5-[5-phenyl-4-(pyridin-2-ylmethylamino)quinazolin-2-yl]pyridine-3-sulfonamide (25) was identified as the lead compound in this series. Compound 25 showed robust effects in rabbit and canine pharmacodynamic models and an acceptable cross-species pharmacokinetic profile and was advanced as the clinical candidate. Further optimization of 25 to mitigate pH-dependent absorption resulted in identification of the corresponding phosphoramide prodrug (29) with an improved solubility and pharmacokinetic profile.
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Affiliation(s)
- Prashantha Gunaga
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - John Lloyd
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Somanadham Mummadi
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Abhisek Banerjee
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Naveen Kumar Dhondi
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - James Hennan
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Veena Subray
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Ramya Jayaram
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Nagendra Rajugowda
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Kommuri Umamaheshwar Reddy
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Duraimurugan Kumaraguru
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Umasankar Mandal
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Dasthagiri Beldona
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Ashok Kumar Adisechen
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Navnath Yadav
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Jayakumar Warrier
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - James A Johnson
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Harinath Sale
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Siva Prasad Putlur
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Ajay Saxena
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Anjaneya Chimalakonda
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Sandhya Mandlekar
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - MaryLee Conder
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Dezhi Xing
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Arun Kumar Gupta
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Anuradha Gupta
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Richard Rampulla
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Arvind Mathur
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Paul Levesque
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Ruth R Wexler
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
| | - Heather J Finlay
- Department of Discovery Chemistry, ‡Department of Biology, and §Department of Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Research and Development , P.O. Box 5400, Princeton, New Jersey 08543-5400, United States.,Department of Discovery Chemistry, Department of Biology, @Department of Biopharmaceutics, #Department of Pharmaceutical Candidate Optimization, and ∇Biocon BMS R&D Center, Syngene International Limited, BMS India Pvt. Limited , Biocon Park, Jigani Link Road, Bommasandra IV, Bangalore 560099, India
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Hormones and sex differences: changes in cardiac electrophysiology with pregnancy. Clin Sci (Lond) 2017; 130:747-59. [PMID: 27128800 DOI: 10.1042/cs20150710] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 02/01/2016] [Indexed: 11/17/2022]
Abstract
Disruption of cardiac electrical activity resulting in palpitations and syncope is often an early symptom of pregnancy. Pregnancy is a time of dramatic and dynamic physiological and hormonal changes during which numerous demands are placed on the heart. These changes result in electrical remodelling which can be detected as changes in the electrocardiogram (ECG). This gestational remodelling is a very under-researched area. There are no systematic large studies powered to determine changes in the ECG from pre-pregnancy, through gestation, and into the postpartum period. The large variability between patients and the dynamic nature of pregnancy hampers interpretation of smaller studies, but some facts are consistent. Gestational cardiac hypertrophy and a physical shift of the heart contribute to changes in the ECG. There are also electrical changes such as an increased heart rate and lengthening of the QT interval. There is an increased susceptibility to arrhythmias during pregnancy and the postpartum period. Some changes in the ECG are clearly the result of changes in ion channel expression and behaviour, but little is known about the ionic basis for this electrical remodelling. Most information comes from animal models, and implicates changes in the delayed-rectifier channels. However, it is likely that there are additional roles for sodium channels as well as changes in calcium homoeostasis. The changes in the electrical profile of the heart during pregnancy and the postpartum period have clear implications for the safety of pregnant women, but the field remains relatively undeveloped.
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40
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Bartos DC, Morotti S, Ginsburg KS, Grandi E, Bers DM. Quantitative analysis of the Ca 2+ -dependent regulation of delayed rectifier K + current I Ks in rabbit ventricular myocytes. J Physiol 2017; 595:2253-2268. [PMID: 28008618 DOI: 10.1113/jp273676] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/12/2016] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS [Ca2+ ]i enhanced rabbit ventricular slowly activating delayed rectifier K+ current (IKs ) by negatively shifting the voltage dependence of activation and slowing deactivation, similar to perfusion of isoproterenol. Rabbit ventricular rapidly activating delayed rectifier K+ current (IKr ) amplitude and voltage dependence were unaffected by high [Ca2+ ]i . When measuring or simulating IKs during an action potential, IKs was not different during a physiological Ca2+ transient or when [Ca2+ ]i was buffered to 500 nm. ABSTRACT The slowly activating delayed rectifier K+ current (IKs ) contributes to repolarization of the cardiac action potential (AP). Intracellular Ca2+ ([Ca2+ ]i ) and β-adrenergic receptor (β-AR) stimulation modulate IKs amplitude and kinetics, but details of these important IKs regulators and their interaction are limited. We assessed the [Ca2+ ]i dependence of IKs in steady-state conditions and with dynamically changing membrane potential and [Ca2+ ]i during an AP. IKs was recorded from freshly isolated rabbit ventricular myocytes using whole-cell patch clamp. With intracellular pipette solutions that controlled free [Ca2+ ]i , we found that raising [Ca2+ ]i from 100 to 600 nm produced similar increases in IKs as did β-AR activation, and the effects appeared additive. Both β-AR activation and high [Ca2+ ]i increased maximally activated tail IKs , negatively shifted the voltage dependence of activation, and slowed deactivation kinetics. These data informed changes in our well-established mathematical model of the rabbit myocyte. In both AP-clamp experiments and simulations, IKs recorded during a normal physiological Ca2+ transient was similar to IKs measured with [Ca2+ ]i clamped at 500-600 nm. Thus, our study provides novel quantitative data as to how physiological [Ca2+ ]i regulates IKs amplitude and kinetics during the normal rabbit AP. Our results suggest that micromolar [Ca2+ ]i , in the submembrane or junctional cleft space, is not required to maximize [Ca2+ ]i -dependent IKs activation during normal Ca2+ transients.
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Affiliation(s)
- Daniel C Bartos
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Stefano Morotti
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Kenneth S Ginsburg
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
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Xiao GS, Zhang YH, Wu W, Sun HY, Wang Y, Li GR. Genistein and tyrphostin AG556 decrease ultra-rapidly activating delayed rectifier K + current of human atria by inhibiting EGF receptor tyrosine kinase. Br J Pharmacol 2017; 174:454-467. [PMID: 28072464 DOI: 10.1111/bph.13710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 12/16/2016] [Accepted: 01/05/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The ultra-rapidly activating delayed rectifier K+ current IKur (encoded by Kv 1.5 or KCNA5) plays an important role in human atrial repolarization. The present study investigates the regulation of this current by protein tyrosine kinases (PTKs). EXPERIMENTAL APPROACH Whole-cell patch voltage clamp technique and immunoprecipitation and Western blotting analysis were used to investigate whether the PTK inhibitors genistein, tyrphostin AG556 (AG556) and PP2 regulate human atrial IKur and hKv1.5 channels stably expressed in HEK 293 cells. KEY RESULTS Human atrial IKur was decreased by genistein (a broad-spectrum PTK inhibitor) and AG556 (a highly selective EGFR TK inhibitor) in a concentration-dependent manner. Inhibition of IKur induced by 30 μM genistein or 10 μM AG556 was significantly reversed by 1 mM orthovanadate (a protein tyrosine phosphatase inhibitor). Similar results were observed in HEK 293 cells stably expressing hKv 1.5 channels. On the other hand, the Src family kinase inhibitor PP2 (1 μM) slightly enhanced IKur and hKv 1.5 current, and the current increase was also reversed by orthovanadate. Immunoprecipitation and Western blotting analysis showed that genistein, AG556, and PP2 decreased tyrosine phosphorylation of hKv 1.5 channels and that the decrease was countered by orthovanadate. CONCLUSION AND IMPLICATIONS The PTK inhibitors genistein and AG556 decrease human atrial IKur and cloned hKv 1.5 channels by inhibiting EGFR TK, whereas the Src kinase inhibitor PP2 increases IKur and hKv 1.5 current. These results imply that EGFR TK and the soluble Src kinases may have opposite effects on human atrial IKur .
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Affiliation(s)
- Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Yan-Hui Zhang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Wei Wu
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Gui-Rong Li
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
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Application of Traditional Chinese Medicine in Treatment of Atrial Fibrillation. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:1381732. [PMID: 28243308 PMCID: PMC5294366 DOI: 10.1155/2017/1381732] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/20/2016] [Accepted: 01/09/2017] [Indexed: 12/24/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, which is related to many cardiac and cerebral vascular diseases, especially stroke. It can therefore increase cardiovascular mortality and all-cause death. The current treatments of AF remain to be western drugs and radiofrequency ablation which are limited by the tolerance of patients, adverse side effects, and high recurrence rate, especially for the elderly. On the contrary, traditional Chinese medicine (TCM) with long history of use involves various treatment methods, including Chinese herbal medicines (CHMs) or bioactive ingredients, Chinese patent medicines, acupuncture, Qigong, and Tai Chi Chuan. With more and more researches reported, the active roles of TCM in AF management have been discovered. Then it is likely that TCM would be effective preventive means and valuable additional remedy for AF. The potential mechanisms further found by numerous experimental studies showed the distinct characteristics of TCM. Some CHMs or bioactive ingredients are atrial-selective, while others are multichannel and multifunctional. Therefore, in this review we summarized the treatment strategies reported in TCM, with the purpose of providing novel ideas and directions for AF management.
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Hwang HR, Tai BY, Cheng PY, Chen PN, Sung PJ, Wen ZH, Hsu CH. Excavatolide B Modulates the Electrophysiological Characteristics and Calcium Homeostasis of Atrial Myocytes. Mar Drugs 2017; 15:md15020025. [PMID: 28125029 PMCID: PMC5334606 DOI: 10.3390/md15020025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/10/2017] [Accepted: 01/18/2017] [Indexed: 12/19/2022] Open
Abstract
Severe bacterial infections caused by sepsis always result in profound physiological changes, including fever, hypotension, arrhythmia, necrosis of tissue, systemic multi-organ dysfunction, and finally death. The lipopolysaccharide (LPS) provokes an inflammatory response under sepsis, which may increase propensity to arrhythmogenesis. Excavatolide B (EXCB) possesses potent anti-inflammatory effects. However, it is not clear whether EXCB could modulate the electrophysiological characteristics and calcium homeostasis of atrial myocytes. This study investigated the effects of EXCB on the atrial myocytes exposed to lipopolysaccharide. A whole-cell patch clamp and indo-1 fluorimetric ratio technique was employed to record the action potential (AP), ionic currents, and intracellular calcium ([Ca2+]i) in single, isolated rabbit left atrial (LA) cardiomyocytes, with and without LPS (1 μg/mL) and LPS + EXCB administration (10 μM) for 6 ± 1 h, in order to investigate the role of EXCB on atrial electrophysiology. In the presence of LPS, EXCB-treated LA myocytes (n = 13) had a longer AP duration at 20% (29 ± 2 vs. 20 ± 2 ms, p < 0.05), 50% (52 ± 4 vs. 40 ± 3 ms, p < 0.05), and 90% (85 ± 5 vs. 68 ± 3 ms, p < 0.05), compared to the LPS-treated cells (n = 12). LPS-treated LA myocytes showed a higher late sodium current, Na+/Ca2+ exchanger current, transient outward current, and delayed rectifier potassium current, but a lower l-type Ca2+ current, than the control LA myocytes. Treatment with EXCB reversed the LPS-induced alterations of the ionic currents. LPS-treated, EXCB-treated, and control LA myocytes exhibited similar Na+ currents. In addition, the LPS-treated LA myocytes exhibited a lower [Ca2+]i content and higher sarcoplasmic reticulum calcium content, than the controls. EXCB reversed the LPS-induced calcium alterations. In conclusion, EXCB modulates LPS-induced LA electrophysiological characteristics and calcium homeostasis, which may contribute to attenuating LPS-induced arrhythmogenesis.
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Affiliation(s)
- Hwong-Ru Hwang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
- Division of Cardiology, Department of Medicine, E-Da Hospital, Kaohsiung 824, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Buh-Yuan Tai
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
- Department of Traditional Medicine, Jianan Mental Hospital, Tainan 717, Taiwan.
| | - Pao-Yun Cheng
- Department of Physiology and Biophysics and Graduate Institute of Physiology, National Defense Medical Center, Taipei 114, Taiwan.
| | - Ping-Nan Chen
- Department of Biomedical Engineering, National Defense Medical Center, Taipei 114, Taiwan.
| | - Ping-Jyun Sung
- National Museum of Marine Biology and Aquarium, Pingtung 944, Taiwan.
- Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung 404, Taiwan.
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Zhi-Hong Wen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung 804, Taiwan.
| | - Chih-Hsueng Hsu
- Division of Cardiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan.
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Mann SA, Imtiaz M, Winbo A, Rydberg A, Perry MD, Couderc JP, Polonsky B, McNitt S, Zareba W, Hill AP, Vandenberg JI. Convergence of models of human ventricular myocyte electrophysiology after global optimization to recapitulate clinical long QT phenotypes. J Mol Cell Cardiol 2016; 100:25-34. [DOI: 10.1016/j.yjmcc.2016.09.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 12/15/2022]
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McKinnon D, Rosati B. Transmural gradients in ion channel and auxiliary subunit expression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:165-186. [PMID: 27702655 DOI: 10.1016/j.pbiomolbio.2016.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/30/2016] [Indexed: 12/11/2022]
Abstract
Evolution has acted to shape the action potential in different regions of the heart in order to produce a maximally stable and efficient pump. This has been achieved by creating regional differences in ion channel expression levels within the heart as well as differences between equivalent cardiac tissues in different species. These region- and species-dependent differences in channel expression are established by regulatory evolution, evolution of the regulatory mechanisms that control channel expression levels. Ion channel auxiliary subunits are obvious targets for regulatory evolution, in order to change channel expression levels and/or modify channel function. This review focuses on the transmural gradients of ion channel expression in the heart and the role that regulation of auxiliary subunit expression plays in generating and shaping these gradients.
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Affiliation(s)
- David McKinnon
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Barbara Rosati
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.
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Inhibitory effects of hesperetin on Kv1.5 potassium channels stably expressed in HEK 293 cells and ultra-rapid delayed rectifier K + current in human atrial myocytes. Eur J Pharmacol 2016; 789:98-108. [DOI: 10.1016/j.ejphar.2016.07.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 06/29/2016] [Accepted: 07/07/2016] [Indexed: 12/16/2022]
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Gloschat CR, Koppel AC, Aras KK, Brennan JA, Holzem KM, Efimov IR. Arrhythmogenic and metabolic remodelling of failing human heart. J Physiol 2016; 594:3963-80. [PMID: 27019074 DOI: 10.1113/jp271992] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/21/2016] [Indexed: 12/24/2022] Open
Abstract
Heart failure (HF) is a major cause of morbidity and mortality worldwide. The global burden of HF continues to rise, with prevalence rates estimated at 1-2% and incidence approaching 5-10 per 1000 persons annually. The complex pathophysiology of HF impacts virtually all aspects of normal cardiac function - from structure and mechanics to metabolism and electrophysiology - leading to impaired mechanical contraction and sudden cardiac death. Pharmacotherapy and device therapy are the primary methods of treating HF, but neither is able to stop or reverse disease progression. Thus, there is an acute need to translate basic research into improved HF therapy. Animal model investigations are a critical component of HF research. However, the translation from cellular and animal models to the bedside is hampered by significant differences between species and among physiological scales. Our studies over the last 8 years show that hypotheses generated in animal models need to be validated in human in vitro models. Importantly, however, human heart investigations can establish translational platforms for safety and efficacy studies before embarking on costly and risky clinical trials. This review summarizes recent developments in human HF investigations of electrophysiology remodelling, metabolic remodelling, and β-adrenergic remodelling and discusses promising new technologies for HF research.
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Affiliation(s)
- C R Gloschat
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - A C Koppel
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - K K Aras
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - J A Brennan
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - K M Holzem
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - I R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
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Abstract
Any disturbance of electrical impulse formation in the heart and of impulse conduction or action potential (AP) repolarization can lead to rhythm disorders. Potassium (K(+)) channels play a prominent role in the AP repolarization process. In this review we describe the causes and mechanisms of proarrhythmic effects that arise as a response to blockers of cardiac K(+) channels. The largest and chemically most diverse groups of compound targets are Kv11.1 (hERG) and Kv7.1 (KvLQT1) channels. Finally, the proarrhythmic propensity of atrial-selective K(+) blockers inhibiting Kv1.5, Kir3.1/3.4, SK, and K2P channels is discussed.
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Affiliation(s)
- Lasse Skibsbye
- Danish Arrhythmia Research Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, 3 Copenhagen N DK-2200, Denmark
| | - Ursula Ravens
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Institut für Pharmakologie und Toxikologie, TU Dresden, Fetscherstrasse 74, Dresden D-01307, Germany.
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Himeno Y, Asakura K, Cha CY, Memida H, Powell T, Amano A, Noma A. A human ventricular myocyte model with a refined representation of excitation-contraction coupling. Biophys J 2016. [PMID: 26200878 DOI: 10.1016/j.bpj.2015.06.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cardiac Ca(2+)-induced Ca(2+) release (CICR) occurs by a regenerative activation of ryanodine receptors (RyRs) within each Ca(2+)-releasing unit, triggered by the activation of L-type Ca(2+) channels (LCCs). CICR is then terminated, most probably by depletion of Ca(2+) in the junctional sarcoplasmic reticulum (SR). Hinch et al. previously developed a tightly coupled LCC-RyR mathematical model, known as the Hinch model, that enables simulations to deal with a variety of functional states of whole-cell populations of a Ca(2+)-releasing unit using a personal computer. In this study, we developed a membrane excitation-contraction model of the human ventricular myocyte, which we call the human ventricular cell (HuVEC) model. This model is a hybrid of the most recent HuVEC models and the Hinch model. We modified the Hinch model to reproduce the regenerative activation and termination of CICR. In particular, we removed the inactivated RyR state and separated the single step of RyR activation by LCCs into triggering and regenerative steps. More importantly, we included the experimental measurement of a transient rise in Ca(2+) concentrations ([Ca(2+)], 10-15 μM) during CICR in the vicinity of Ca(2+)-releasing sites, and thereby calculated the effects of the local Ca(2+) gradient on CICR as well as membrane excitation. This HuVEC model successfully reconstructed both membrane excitation and key properties of CICR. The time course of CICR evoked by an action potential was accounted for by autonomous changes in an instantaneous equilibrium open probability of couplons. This autonomous time course was driven by a core feedback loop including the pivotal local [Ca(2+)], influenced by a time-dependent decay in the SR Ca(2+) content during CICR.
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Affiliation(s)
- Yukiko Himeno
- Biosimulation Research Center, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Keiichi Asakura
- Biosimulation Research Center, College of Life Sciences, Ritsumeikan University, Shiga, Japan; Nippon Shinyaku Co., Ltd., Kyoto, Japan
| | - Chae Young Cha
- Biosimulation Research Center, College of Life Sciences, Ritsumeikan University, Shiga, Japan; Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Hiraku Memida
- Biosimulation Research Center, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Trevor Powell
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Akira Amano
- Biosimulation Research Center, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Akinori Noma
- Biosimulation Research Center, College of Life Sciences, Ritsumeikan University, Shiga, Japan.
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50
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Abstract
Cardiac delayed rectifier potassium channels conduct outward potassium currents during the plateau phase of action potentials and play pivotal roles in cardiac repolarization. These include IKs, IKr and the atrial specific IKur channels. In this article, we will review their molecular identities and biophysical properties. Mutations in the genes encoding delayed rectifiers lead to loss- or gain-of-function phenotypes, disrupt normal cardiac repolarization and result in various cardiac rhythm disorders, including congenital Long QT Syndrome, Short QT Syndrome and familial atrial fibrillation. We will also discuss the prospect of using delayed rectifier channels as therapeutic targets to manage cardiac arrhythmia.
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Affiliation(s)
- Lei Chen
- Department of Pharmacology, College of Physicians & Surgeons of Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Kevin J Sampson
- Department of Pharmacology, College of Physicians & Surgeons of Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Robert S Kass
- Department of Pharmacology, College of Physicians & Surgeons of Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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