1
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Li T, Rong L, Gao Y, Cheng W. The causal relationship between obesity, obstructive sleep apnea and atrial fibrillation: a study based on mediated Mendelian randomization. Front Cardiovasc Med 2024; 11:1406192. [PMID: 38707891 PMCID: PMC11066229 DOI: 10.3389/fcvm.2024.1406192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 04/08/2024] [Indexed: 05/07/2024] Open
Abstract
Background Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with obesity and obstructive sleep apnea syndrome (OSA). Obesity and OSA may increase the risk of AF by affecting cardiovascular health. Methods The study used the Mendelian randomization (MR) approach, combined with two-sample and multivariable analyses, to assess the relationships between obesity, OSA, and AF. The study utilized GWAS data and applied various statistical methods for the analysis. Results The study found that obesity increased the risk of OSA, which in turn significantly increased the risk of AF. Through mediating MR analysis, it was found that OSA played a certain role in the causal relationship between obesity and AF, with about 6.4% of the risk of AF being mediated by OSA. Conclusion This study highlights the relationships among obesity, OSA, and AF, providing useful guidance for future clinical researches.
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Affiliation(s)
| | | | | | - Wei Cheng
- Department of Cardiology, Anhui No.2 Provincial People's Hospital, Hefei, Anhui, China
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2
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Perike S, Gonzalez-Gonzalez FJ, Abu-Taha I, Damen FW, Hanft LM, Lizama KS, Aboonabi A, Capote AE, Aguilar-Sanchez Y, Levin B, Han Z, Sridhar A, Grand J, Martin J, Akar JG, Warren CM, Solaro RJ, Sang-Ging O, Darbar D, McDonald KS, Goergen CJ, Wolska BM, Dobrev D, Wehrens XH, McCauley MD. PPP1R12C Promotes Atrial Hypocontractility in Atrial Fibrillation. Circ Res 2023; 133:758-771. [PMID: 37737016 PMCID: PMC10616980 DOI: 10.1161/circresaha.123.322516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023]
Abstract
BACKGROUND Atrial fibrillation (AF)-the most common sustained cardiac arrhythmia-increases thromboembolic stroke risk 5-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C (protein phosphatase 1 regulatory subunit 12C)-the PP1 (protein phosphatase 1) regulatory subunit targeting MLC2a (atrial myosin light chain 2)-causes hypophosphorylation of MLC2a and results in atrial hypocontractility. METHODS Right atrial appendage tissues were isolated from human patients with AF versus sinus rhythm controls. Western blots, coimmunoprecipitation, and phosphorylation studies were performed to examine how the PP1c (PP1 catalytic subunit)-PPP1R12C interaction causes MLC2a dephosphorylation. In vitro studies of pharmacological MRCK (myotonic dystrophy kinase-related Cdc42-binding kinase) inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with electrophysiology studies. RESULTS In human patients with AF, PPP1R12C expression was increased 2-fold versus sinus rhythm controls (P=2.0×10-2; n=12 and 12 in each group) with >40% reduction in MLC2a phosphorylation (P=1.4×10-6; n=12 and 12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF (P=2.9×10-2 and 6.7×10-3, respectively; n=8 and 8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a and dephosphorylation of MLC2a. Mice treated with lentiviral PPP1R12C vector demonstrated a 150% increase in left atrial size versus controls (P=5.0×10-6; n=12, 8, and 12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in mice treated with lentiviral PPP1R12C vector was significantly higher than in controls (P=1.8×10-2 and 4.1×10-2, respectively; n=6, 6, and 5). CONCLUSIONS Patients with AF exhibit increased levels of PPP1R12C protein compared with controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key determinant of atrial contractility in AF.
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Affiliation(s)
- Srikanth Perike
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Francisco J. Gonzalez-Gonzalez
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Issam Abu-Taha
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Germany
| | - Frederick W. Damen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN
| | - Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Ken S. Lizama
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Anahita Aboonabi
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Andrielle E. Capote
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Yuriana Aguilar-Sanchez
- Department of Integrative Physiology and The Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
| | | | - Zhenbo Han
- Department of Pharmacology and Regenerative Medicine, College of Medicine,University of Illinois at Chicago
| | - Arvind Sridhar
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
| | - Jacob Grand
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
| | | | | | - Chad M. Warren
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - R. John Solaro
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Ong Sang-Ging
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Pharmacology and Regenerative Medicine, College of Medicine,University of Illinois at Chicago
| | - Dawood Darbar
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Craig J. Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN
| | - Beata M. Wolska
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Germany
- Department of Integrative Physiology and The Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
- Department of Medicine, Montréal Heart Institute and Université de Montréal, Montréal, Canada
| | - Xander H.T. Wehrens
- Department of Integrative Physiology and The Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
| | - Mark D. McCauley
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
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3
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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [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: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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4
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Perike S, Gonzalez-Gonzalez FJ, Abu-Taha I, Damen FW, Lizama KS, Aboonabi A, Capote AE, Aguilar-Sanchez Y, Levin B, Han Z, Sridhar A, Grand J, Martin J, Akar JG, Warren CM, Solaro RJ, Ong SG, Darbar D, Goergen CJ, Wolska BM, Dobrev D, Wehrens XHT, McCauley MD. Myosin Light Chain Dephosphorylation by PPP1R12C Promotes Atrial Hypocontractility in Atrial Fibrillation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537590. [PMID: 37131731 PMCID: PMC10153354 DOI: 10.1101/2023.04.19.537590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, increases thromboembolic stroke risk five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C, the PP1 regulatory subunit targeting atrial myosin light chain 2 (MLC2a), causes hypophosphorylation of MLC2a and results in atrial hypocontractility. Methods Right atrial appendage tissues were isolated from human AF patients versus sinus rhythm (SR) controls. Western blots, co-immunoprecipitation, and phosphorylation studies were performed to examine how the PP1c-PPP1R12C interaction causes MLC2a de-phosphorylation. In vitro studies of pharmacologic MRCK inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with EP studies. Results In human patients with AF, PPP1R12C expression was increased two-fold versus SR controls ( P =2.0×10 -2 , n=12,12 in each group) with > 40% reduction in MLC2a phosphorylation ( P =1.4×10 -6 , n=12,12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF ( P =2.9×10 -2 and 6.7×10 -3 respectively, n=8,8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Lenti-12C mice demonstrated a 150% increase in LA size versus controls ( P =5.0×10 -6 , n=12,8,12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in Lenti-12C mice was significantly higher than controls ( P =1.8×10 -2 and 4.1×10 -2 respectively, n= 6,6,5). Conclusions AF patients exhibit increased levels of PPP1R12C protein compared to controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key determinant of atrial contractility in AF.
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5
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Yu C, Deng XJ, Xu D. Gene mutations in comorbidity of epilepsy and arrhythmia. J Neurol 2023; 270:1229-1248. [PMID: 36376730 DOI: 10.1007/s00415-022-11430-2] [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: 07/31/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022]
Abstract
Epilepsy is one of the most common neurological disorders, and sudden unexpected death in epilepsy (SUDEP) is the most severe outcome of refractory epilepsy. Arrhythmia is one of the heterogeneous factors in the pathophysiological mechanism of SUDEP with a high incidence in patients with refractory epilepsy, increasing the risk of premature death. The gene co-expressed in the brain and heart is supposed to be the genetic basis between epilepsy and arrhythmia, among which the gene encoding ion channel contributes to the prevalence of "cardiocerebral channelopathy" theory. Nevertheless, this theory could only explain the molecular mechanism of comorbid arrhythmia in part of patients with epilepsy (PWE). Therefore, we summarized the mutant genes that can induce comorbidity of epilepsy and arrhythmia and the possible corresponding treatments. These variants involved the genes encoding sodium, potassium, calcium and HCN channels, as well as some non-ion channel coding genes such as CHD4, PKP2, FHF1, GNB5, and mitochondrial genes. The relationship between genotype and clinical phenotype was not simple linear. Indeed, genes co-expressed in the brain and heart could independently induce epilepsy and/or arrhythmia. Mutant genes in brain could affect cardiac rhythm through central or peripheral regulation, while in the heart it could also affect cerebral electrical activity by changing the hemodynamics or internal environment. Analysis of mutations in comorbidity of epilepsy and arrhythmia could refine and expand the theory of "cardiocerebral channelopathy" and provide new insights for risk stratification of premature death and corresponding precision therapy in PWE.
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Affiliation(s)
- Cheng Yu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Xue-Jun Deng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Da Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China.
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6
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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7
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Costagliola G, Orsini A, Coll M, Brugada R, Parisi P, Striano P. The brain-heart interaction in epilepsy: implications for diagnosis, therapy, and SUDEP prevention. Ann Clin Transl Neurol 2021; 8:1557-1568. [PMID: 34047488 PMCID: PMC8283165 DOI: 10.1002/acn3.51382] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/15/2021] [Accepted: 04/27/2021] [Indexed: 12/17/2022] Open
Abstract
The influence of the central nervous system and autonomic system on cardiac activity is being intensively studied, as it contributes to the high rate of cardiologic comorbidities observed in people with epilepsy. Indeed, neuroanatomic connections between the brain and the heart provide links that allow cardiac arrhythmias to occur in response to brain activation, have been shown to produce arrhythmia both experimentally and clinically. Moreover, seizures may induce a variety of transient cardiac effects, which include changes in heart rate, heart rate variability, arrhythmias, asystole, and other ECG abnormalities, and can trigger the development of Takotsubo syndrome. People with epilepsy are at a higher risk of death than the general population, and sudden unexpected death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of death. Although the cause of SUDEP is still unknown, cardiac abnormalities during and between seizures could play a significant role in its pathogenesis, as highlighted by studies on animal models of SUDEP and registration of SUDEP events. Recently, genetic mutations in genes co-expressed in the heart and brain, which may result in epilepsy and cardiac comorbidity/increased risk for SUDEP, have been described. Recognition and a better understanding of brain-heart interactions, together with new advances in sequencing techniques, may provide new insights into future novel therapies and help in the prevention of cardiac dysfunction and sudden death in epileptic individuals.
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Affiliation(s)
- Giorgio Costagliola
- Pediatric Clinic, Santa Chiara's University Hospital, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Alessandro Orsini
- Pediatric Clinic, Santa Chiara's University Hospital, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Monica Coll
- Cardiovascular Genetics Center, Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain.,Medical Science Department, School of Medicine, University of Girona, Girona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Cardiology Service, Hospital Josep Trueta, Girona, Spain
| | - Pasquale Parisi
- Chair of Pediatrics, NESMOS Department, Faculty of Medicine and Psychology, Sapienza University, Sant' Andrea Hospital, Rome, Italy
| | - Pasquale Striano
- IRCCS Istituto Giannina Gaslini, Genova, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
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8
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Trosclair K, Si M, Watts M, Gautier NM, Voigt N, Traylor J, Bitay M, Baczko I, Dobrev D, Hamilton KA, Bhuiyan MS, Dominic P, Glasscock E. Kv1.1 potassium channel subunit deficiency alters ventricular arrhythmia susceptibility, contractility, and repolarization. Physiol Rep 2021; 9:e14702. [PMID: 33427415 PMCID: PMC7798052 DOI: 10.14814/phy2.14702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/11/2022] Open
Abstract
Epilepsy-associated Kv1.1 voltage-gated potassium channel subunits encoded by the Kcna1 gene have traditionally been considered absent in heart, but recent studies reveal they are expressed in cardiomyocytes where they could regulate intrinsic cardiac electrophysiology. Although Kv1.1 now has a demonstrated functional role in atria, its role in the ventricles has never been investigated. In this work, electrophysiological, histological, and gene expression approaches were used to explore the consequences of Kv1.1 deficiency in the ventricles of Kcna1 knockout (KO) mice at the organ, cellular, and molecular levels to determine whether the absence of Kv1.1 leads to ventricular dysfunction that increases the risk of premature or sudden death. When subjected to intracardiac pacing, KO mice showed normal baseline susceptibility to inducible ventricular arrhythmias (VA) but resistance to VA under conditions of sympathetic challenge with isoproterenol. Echocardiography revealed cardiac contractile dysfunction manifesting as decreased ejection fraction and fractional shortening. In whole-cell patch-clamp recordings, KO ventricular cardiomyocytes exhibited action potential prolongation indicative of impaired repolarization. Imaging, histological, and transcript analyses showed no evidence of structural or channel gene expression remodeling, suggesting that the observed deficits are likely electrogenic due to Kv1.1 deficiency. Immunoblots of patient heart samples detected the presence of Kv1.1 at relatively high levels, implying that Kv1.1 contributes to human cardiac electrophysiology. Taken together, this work describes an important functional role for Kv1.1 in ventricles where its absence causes repolarization and contractility deficits but reduced susceptibility to arrhythmia under conditions of sympathetic drive.
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Affiliation(s)
- Krystle Trosclair
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Man Si
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Megan Watts
- Department of Internal MedicineSection of CardiologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Nicole M. Gautier
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Niels Voigt
- Institute of Pharmacology and ToxicologyUniversity Medical Center GoettingenGoettingenGermany
- DZHK (German Center for Cardiovascular Research)GöttingenGermany
| | - James Traylor
- Department of PathologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Miklós Bitay
- Department of Cardiac Surgery2nd Department of Medicine and Cardiology CenterUniversity of SzegedSzegedHungary
| | - Istvan Baczko
- Department of Pharmacology and PharmacotherapyInterdisciplinary Excellence CentreUniversity of SzegedSzegedHungary
| | - Dobromir Dobrev
- Institute of PharmacologyWest German Heart and Vascular CenterUniversity Duisburg‐EssenEssenGermany
| | - Kathryn A. Hamilton
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Md. Shenuarin Bhuiyan
- Department of PathologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Paari Dominic
- Department of Internal MedicineSection of CardiologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Edward Glasscock
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
- Department of Biological SciencesSouthern Methodist UniversityDallasTXUSA
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9
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Abstract
Voltage-gated Kv1.1 potassium channel α-subunits are broadly expressed in the nervous system where they act as critical regulators of neuronal excitability. Mutations in the KCNA1 gene, which encodes Kv1.1, are associated with the neurological diseases episodic ataxia and epilepsy. Studies in mouse models have shown that Kv1.1 is important for neural control of the heart and that Kcna1 deletion leads to cardiac dysfunction that appears to be brain-driven. Traditionally, KCNA1 was not believed to be expressed in the heart. However, recent studies have revealed that Kv1.1 subunits are not only present in cardiomyocytes, but that they also make an important heart-intrinsic functional contribution to outward K+ currents and action potential repolarization. This review recounts the winding history of discovery of KCNA1 gene expression and neurocardiac function from fruit flies to mammals and from brain to heart and looks at some of the salient questions that remain to be answered regarding emerging cardiac roles of Kv1.1.
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Affiliation(s)
- Edward Glasscock
- a Department of Biological Sciences , Southern Methodist University , Dallas , TX , USA
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10
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D’Adamo MC, Liantonio A, Rolland JF, Pessia M, Imbrici P. Kv1.1 Channelopathies: Pathophysiological Mechanisms and Therapeutic Approaches. Int J Mol Sci 2020; 21:ijms21082935. [PMID: 32331416 PMCID: PMC7215777 DOI: 10.3390/ijms21082935] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 04/19/2020] [Accepted: 04/20/2020] [Indexed: 12/27/2022] Open
Abstract
Kv1.1 belongs to the Shaker subfamily of voltage-gated potassium channels and acts as a critical regulator of neuronal excitability in the central and peripheral nervous systems. KCNA1 is the only gene that has been associated with episodic ataxia type 1 (EA1), an autosomal dominant disorder characterized by ataxia and myokymia and for which different and variable phenotypes have now been reported. The iterative characterization of channel defects at the molecular, network, and organismal levels contributed to elucidating the functional consequences of KCNA1 mutations and to demonstrate that ataxic attacks and neuromyotonia result from cerebellum and motor nerve alterations. Dysfunctions of the Kv1.1 channel have been also associated with epilepsy and kcna1 knock-out mouse is considered a model of sudden unexpected death in epilepsy. The tissue-specific association of Kv1.1 with other Kv1 members, auxiliary and interacting subunits amplifies Kv1.1 physiological roles and expands the pathogenesis of Kv1.1-associated diseases. In line with the current knowledge, Kv1.1 has been proposed as a novel and promising target for the treatment of brain disorders characterized by hyperexcitability, in the attempt to overcome limited response and side effects of available therapies. This review recounts past and current studies clarifying the roles of Kv1.1 in and beyond the nervous system and its contribution to EA1 and seizure susceptibility as well as its wide pharmacological potential.
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Affiliation(s)
- Maria Cristina D’Adamo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida MDS-2080, Malta; (M.C.D.); (M.P.)
| | - Antonella Liantonio
- Department of Pharmacy–Drug Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy;
| | | | - Mauro Pessia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida MDS-2080, Malta; (M.C.D.); (M.P.)
- Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain Po Box 17666, UAE
| | - Paola Imbrici
- Department of Pharmacy–Drug Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy;
- Correspondence:
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Clinical Spectrum of KCNA1 Mutations: New Insights into Episodic Ataxia and Epilepsy Comorbidity. Int J Mol Sci 2020; 21:ijms21082802. [PMID: 32316562 PMCID: PMC7215408 DOI: 10.3390/ijms21082802] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations in the KCNA1 gene, which encodes voltage-gated Kv1.1 potassium channel α-subunits, cause a variety of human diseases, complicating simple genotype–phenotype correlations in patients. KCNA1 mutations are primarily associated with a rare neurological movement disorder known as episodic ataxia type 1 (EA1). However, some patients have EA1 in combination with epilepsy, whereas others have epilepsy alone. KCNA1 mutations can also cause hypomagnesemia and paroxysmal dyskinesia in rare cases. Why KCNA1 variants are associated with such phenotypic heterogeneity in patients is not yet understood. In this review, literature databases (PubMed) and public genetic archives (dbSNP and ClinVar) were mined for known pathogenic or likely pathogenic mutations in KCNA1 to examine whether patterns exist between mutation type and disease manifestation. Analyses of the 47 deleterious KCNA1 mutations that were identified revealed that epilepsy or seizure-related variants tend to cluster in the S1/S2 transmembrane domains and in the pore region of Kv1.1, whereas EA1-associated variants occur along the whole length of the protein. In addition, insights from animal models of KCNA1 channelopathy were considered, as well as the possible influence of genetic modifiers on disease expressivity and severity. Elucidation of the complex relationship between KCNA1 variants and disease will enable better diagnostic risk assessment and more personalized therapeutic strategies for KCNA1 channelopathy.
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12
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Trosclair K, Dhaibar HA, Gautier NM, Mishra V, Glasscock E. Neuron-specific Kv1.1 deficiency is sufficient to cause epilepsy, premature death, and cardiorespiratory dysregulation. Neurobiol Dis 2020; 137:104759. [PMID: 31978607 DOI: 10.1016/j.nbd.2020.104759] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/03/2020] [Accepted: 01/20/2020] [Indexed: 12/14/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality, but the precise cellular substrates involved remain elusive. Epilepsy-associated ion channel genes with co-expression in brain and heart have been proposed as SUDEP candidate genes since they provide a singular unifying link between seizures and lethal cardiac arrhythmias. Here, we generated a conditional knockout (cKO) mouse with neuron-specific deletion of Kcna1, a SUDEP-associated gene with brain-heart co-expression, to test whether seizure-evoked cardiac arrhythmias and SUDEP require the absence of Kv1.1 in both brain and heart or whether ablation in neurons is sufficient. To obtain cKO mice, we developed a floxed Kcna1 mouse which we crossed to mice with the Synapsin1-Cre transgene, which selectively deletes Kcna1 in most neurons. Molecular analyses confirmed neuron-specific Kcna1 deletion in cKO mice and corresponding loss of Kv1.1 except in cerebellum where Synapsin1-Cre is not highly expressed. Survival studies and electroencephalography, electrocardiography, and plethysmography recordings showed that cKO mice exhibit premature death, epilepsy, and cardiorespiratory dysregulation but to a lesser degree than global knockouts. Heart rate variability (HRV) was increased in cKO mice with peaks during daytime suggesting disturbed diurnal HRV patterns as a SUDEP biomarker. Residual Kv1.1 expression in cKO cerebellum suggests it may play an unexpected role in regulating ictal cardiorespiratory dysfunction and SUDEP risk. This work demonstrates the principle that channelopathies with brain-heart expression patterns can increase death risk by brain-driven mechanisms alone without a functionally compromised heart, reinforcing seizure control as a primary clinical strategy for SUDEP prevention.
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Affiliation(s)
- Krystle Trosclair
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Hemangini A Dhaibar
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Nicole M Gautier
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Vikas Mishra
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Edward Glasscock
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America; Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States of America.
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Sutanto H, Laudy L, Clerx M, Dobrev D, Crijns HJ, Heijman J. Maastricht antiarrhythmic drug evaluator (MANTA): A computational tool for better understanding of antiarrhythmic drugs. Pharmacol Res 2019; 148:104444. [DOI: 10.1016/j.phrs.2019.104444] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/10/2019] [Accepted: 09/03/2019] [Indexed: 12/14/2022]
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Dhaibar H, Gautier NM, Chernyshev OY, Dominic P, Glasscock E. Cardiorespiratory profiling reveals primary breathing dysfunction in Kcna1-null mice: Implications for sudden unexpected death in epilepsy. Neurobiol Dis 2019; 127:502-511. [PMID: 30974168 PMCID: PMC6588471 DOI: 10.1016/j.nbd.2019.04.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/14/2019] [Accepted: 04/05/2019] [Indexed: 12/20/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality, but the relative importance of underlying cardiac and respiratory mechanisms remains unclear. To illuminate the interactions between seizures, respiration, cardiac function, and sleep that contribute to SUDEP risk, here we developed a mouse epilepsy monitoring unit (EMU) to simultaneously record video, electroencephalography (EEG), electromyography (EMG), plethysmography, and electrocardiography (ECG) in a commonly used genetic model of SUDEP, the Kcna1 knockout (Kcna1-/-) mouse. During interictal periods, Kcna1-/- mice exhibited an abnormal absence of post-sigh apneas and a 3-fold increase in respiratory variability. During spontaneous convulsive seizures, Kcna1-/- mice displayed an array of aberrant breathing patterns that always preceded cardiac abnormalities. These findings support respiratory dysfunction as a primary risk factor for susceptibility to deleterious cardiorespiratory sequelae in epilepsy and reveal a new role for Kcna1-encoded Kv1.1 channels in the regulation of basal respiratory physiology.
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Affiliation(s)
- Hemangini Dhaibar
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, USA.
| | - Nicole M Gautier
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, USA.
| | - Oleg Y Chernyshev
- Department of Neurology, Division of Sleep Medicine, Louisiana State University Health Sciences Center Shreveport, LA 71103, USA.
| | - Paari Dominic
- Department of Internal Medicine, Section of Cardiology, Louisiana State University Health Sciences Center Shreveport, LA 71103, USA.
| | - Edward Glasscock
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, USA.
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15
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Peyronnet R, Ravens U. Atria-selective antiarrhythmic drugs in need of alliance partners. Pharmacol Res 2019; 145:104262. [PMID: 31059791 DOI: 10.1016/j.phrs.2019.104262] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/30/2019] [Accepted: 05/03/2019] [Indexed: 12/15/2022]
Abstract
Atria-selective antiarrhythmic drugs in need of alliance partners. Guideline-based treatment of atrial fibrillation (AF) comprises prevention of thromboembolism and stroke, as well as antiarrhythmic therapy by drugs, electrical rhythm conversion, ablation and surgical procedures. Conventional antiarrhythmic drugs are burdened with unwanted side effects including a propensity of triggering life-threatening ventricular fibrillation. In order to solve this therapeutic dilemma, 'atria-selective' antiarrhythmic drugs have been developed for the treatment of supraventricular arrhythmias. These drugs are designed to aim at atrial targets, taking advantage of differences in atrial and ventricular ion channel expression and function. However it is not clear, whether such drugs are sufficiently antiarrhythmic or whether they are in need of an alliance partner for clinical efficacy. Atria-selective Na+ channel blockers display fast dissociation kinetics and high binding affinity to inactivated channels. Compounds targeting atria-selective K+ channels include blockers of ultra rapid delayed rectifier (Kv1.5) or acetylcholine-activated inward rectifier K+ channels (Kir3.x), inward rectifying K+ channels (Kir2.x), Ca2+-activated K+ channels of small conductance (SK), weakly rectifying two-pore domain K+ channels (K2P), and transient receptor potential channels (TRP). Despite good antiarrhythmic data from in-vitro and animal model experiments, clinical efficacy of atria-selective antiarrhythmic drugs remains to be demonstrated. In the present review we will briefly summarize the novel compounds and their proposed antiarrhythmic action. In addition, we will discuss the evidence for putative improvement of antiarrhythmic efficacy and potency by addressing multiple pathophysiologically relevant targets as possible alliance partners.
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Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany; Institute of Physiology, Medical Faculty TU Dresden, Dresden, Germany.
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16
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Si M, Trosclair K, Hamilton KA, Glasscock E. Genetic ablation or pharmacological inhibition of Kv1.1 potassium channel subunits impairs atrial repolarization in mice. Am J Physiol Cell Physiol 2019; 316:C154-C161. [PMID: 30427720 PMCID: PMC6397341 DOI: 10.1152/ajpcell.00335.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 11/06/2018] [Accepted: 11/13/2018] [Indexed: 12/14/2022]
Abstract
Voltage-gated Kv1.1 potassium channel α-subunits, encoded by the Kcna1 gene, have traditionally been regarded as neural-specific with no expression or function in the heart. However, recent data revealed that Kv1.1 subunits are expressed in atria where they may have an overlooked role in controlling repolarization and arrhythmia susceptibility independent of the nervous system. To explore this concept in more detail and to identify functional and molecular effects of Kv1.1 channel impairment in the heart, atrial cardiomyocyte patch-clamp electrophysiology and gene expression analyses were performed using Kcna1 knockout ( Kcna1-/-) mice. Specifically, we hypothesized that Kv1.1 subunits contribute to outward repolarizing K+ currents in mouse atria and that their absence prolongs cardiac action potentials. In voltage-clamp experiments, dendrotoxin-K (DTX-K), a Kv1.1-specific inhibitor, significantly reduced peak outward K+ currents in wild-type (WT) atrial cells but not Kcna1-/- cells, demonstrating an important contribution by Kv1.1-containing channels to mouse atrial repolarizing currents. In current-clamp recordings, Kcna1-/- atrial myocytes exhibited significant action potential prolongation which was exacerbated in right atria, effects that were partially recapitulated in WT cells by application of DTX-K. Quantitative RT-PCR measurements showed mRNA expression remodeling in Kcna1-/- atria for several ion channel genes that contribute to the atrial action potential including the Kcna5, Kcnh2, and Kcnj2 potassium channel genes and the Scn5a sodium channel gene. This study demonstrates a previously undescribed heart-intrinsic role for Kv1.1 subunits in mediating atrial repolarization, thereby adding a new member to the already diverse collection of known K+ channels in the heart.
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Affiliation(s)
- Man Si
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center , Shreveport, Louisiana
| | - Krystle Trosclair
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center , Shreveport, Louisiana
| | - Kathryn A Hamilton
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center , Shreveport, Louisiana
| | - Edward Glasscock
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center , Shreveport, Louisiana
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17
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Marques FZ, Chu PY, Ziemann M, Kaspi A, Kiriazis H, Du XJ, El-Osta A, Kaye DM. Age-Related Differential Structural and Transcriptomic Responses in the Hypertensive Heart. Front Physiol 2018; 9:817. [PMID: 30038575 PMCID: PMC6046461 DOI: 10.3389/fphys.2018.00817] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/11/2018] [Indexed: 01/20/2023] Open
Abstract
While aging is a critical risk factor for heart failure, it remains uncertain whether the aging heart responds differentially to a hypertensive stimuli. Here we investigated phenotypic and transcriptomic differences between the young and aging heart using a mineralocorticoid-excess model of hypertension. Ten-week (“young”) and 36-week (“aging”) mice underwent a unilateral uninephrectomy with deoxycorticosterone acetate (DOCA) pellet implantation (n = 6–8/group) and were followed for 6 weeks. Cardiac structure and function, blood pressure (BP) and the cardiac transcriptome were subsequently examined. Young and aging DOCA mice had high BP, increased cardiac mass, cardiac hypertrophy, and fibrosis. Left ventricular end-diastolic pressure increased in aging DOCA-treated mice in contrast to young DOCA mice. Interstitial and perivascular fibrosis occurred in response to DOCA, but perivascular fibrosis was greater in aging mice. Transcriptomic analysis showed that young mice had features of higher oxidative stress, likely due to activation of the respiratory electron transport chain. In contrast, aging mice showed up-regulation of collagen formation in association with activation of innate immunity together with markers of inflammation including cytokine and platelet signaling. In comparison to younger mice, aging mice demonstrated different phenotypic and molecular responses to hypertensive stress. These findings have potential implications for the pathogenesis of age-related forms of cardiovascular disease, particularly heart failure.
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Affiliation(s)
- Francine Z Marques
- Heart Failure Research Group, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Department of Pharmacology, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
| | - Po-Yin Chu
- Heart Failure Research Group, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Mark Ziemann
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC, Australia
| | - Antony Kaspi
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC, Australia
| | - Helen Kiriazis
- Experimental Cardiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Xiao-Jun Du
- Experimental Cardiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Central Clinical School, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
| | - Assam El-Osta
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC, Australia.,Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, Hong Kong.,Department of Pathology, The University of Melbourne, Melbourne, VIC, Australia
| | - David M Kaye
- Heart Failure Research Group, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Central Clinical School, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia.,Heart Centre, Alfred Hospital, Melbourne, VIC, Australia
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18
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Schmidt C, Peyronnet R. Voltage-gated and stretch-activated potassium channels in the human heart : Pathophysiological and clinical significance. Herzschrittmacherther Elektrophysiol 2018; 29:36-42. [PMID: 29305705 DOI: 10.1007/s00399-017-0541-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/14/2017] [Indexed: 12/14/2022]
Abstract
Ion channels are essential for electrical signaling and contractility in cardiomyocytes. Detailed knowledge about the molecular function and regulation of cardiac ion channels is crucial for understanding cardiac physiology and pathophysiology especially in the field of arrhythmias. This review aims at providing a general overview on the identity, functional characteristics, and roles of voltage-gated as well as stretch-activated potassium selective channels in the heart. In particular, we will highlight potential therapeutic targets as well as the emerging fields of future investigations.
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Affiliation(s)
- Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center, Medical Center - University of Freiburg, and Faculty of Medicine, University of Freiburg, Elsässer Straße 2q, 79110, Freiburg, Germany.
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19
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The crucial role of activin A/ALK4 pathway in the pathogenesis of Ang-II-induced atrial fibrosis and vulnerability to atrial fibrillation. Basic Res Cardiol 2017. [PMID: 28639003 DOI: 10.1007/s00395-017-0634-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Atrial fibrosis, the hallmark of structural remodeling associated with atrial fibrillation (AF), is characterized by abnormal proliferation of atrial fibroblasts and excessive deposition of extracellular matrix. Transforming growth factor-β1 (TGF-β1)/activin receptor-like kinase 5 (ALK5)/Smad2/3/4 pathway has been reported to be involved in the process. Recent studies have implicated both activin A and its specific downstream component activin receptor-like kinase 4 (ALK4) in stimulating fibrosis in non-cardiac organs. We recently reported that ALK4 haplodeficiency attenuated the pressure overload- and myocardial infarction-induced ventricular fibrosis. However, the role of activin A/ALK4 in the pathogenesis of atrial fibrosis and vulnerability to AF remains unknown. Our study provided experimental and clinical evidence for the involvement of activin A and ALK4 in the pathophysiology of atrial fibrosis and AF. Patients with AF had higher activin A and ALK4 expression in atriums as compared to individuals devoid of AF. After angiotensin-II (Ang-II) stimulation which mimicked atrial fibrosis progression, ALK4-deficient mice showed lower expression of ALK4 in atriums, reduced activation of atrial fibroblasts, blunted atrial enlargement and atrial fibrosis, and further reduced AF vulnerability upon right atrial electrophysiological studies as compared to wild-type littermates. Moreover, we found that apart from the well-known TGF-β1/ALK5 pathway, the activation of activin A/ALK4/smad2/3 pathway played an important role in the pathogenesis of Ang-II-mediated atrial fibrosis and inducibility of AF, suggesting that targeting ALK4 might be a potential therapy for atrial fibrosis and AF.
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20
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TREK-1 (K2P2.1) K+ channels are suppressed in patients with atrial fibrillation and heart failure and provide therapeutic targets for rhythm control. Basic Res Cardiol 2016; 112:8. [DOI: 10.1007/s00395-016-0597-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/12/2016] [Indexed: 12/16/2022]
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Regulation of human cardiac potassium channels by full-length KCNE3 and KCNE4. Sci Rep 2016; 6:38412. [PMID: 27922120 PMCID: PMC5138848 DOI: 10.1038/srep38412] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/09/2016] [Indexed: 12/23/2022] Open
Abstract
Voltage-gated potassium (Kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane KCNE subunits. After recently uncovering novel, N-terminally extended (L) KCNE3 and KCNE4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac Kv channel α subunits expressed in Xenopus laevis oocytes. As previously reported for short isoforms KCNE3S and KCNE4S, KCNE3L inhibited hERG; KCNE4L inhibited Kv1.1; neither form regulated the HCN1 pacemaker channel. Unlike KCNE4S, KCNE4L was a potent inhibitor of Kv4.2 and Kv4.3; co-expression of cytosolic β subunit KChIP2, which regulates Kv4 channels in cardiac myocytes, partially relieved Kv4.3 but not Kv4.2 inhibition. Inhibition of Kv4.2 and Kv4.3 by KCNE3L was weaker, and its inhibition of Kv4.2 abolished by KChIP2. KCNE3L and KCNE4L also exhibited subunit-specific effects on Kv4 channel complex inactivation kinetics, voltage dependence and recovery. Further supporting the potential physiological significance of the robust functional effects of KCNE4L on Kv4 channels, KCNE4L protein was detected in human atrium, where it co-localized with Kv4.3. The findings establish functional effects of novel human cardiac-expressed KCNE isoforms and further contribute to our understanding of the potential mechanisms influencing cardiomyocyte repolarization.
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Abstract
Atrial fibrillation (AF) is an extremely prevalent arrhythmia that presents a wide range of therapeutic challenges. AF usually begins in a self-terminating paroxysmal form (pAF). With time, the AF pattern often evolves to become persistent (nonterminating within 7 days). Important differences exist between pAF and persistent AF in terms of clinical features, in particular the responsiveness to antiarrhythmic drugs and ablation therapy. AF mechanisms have been extensively reviewed, but few or no Reviews focus specifically on the pathophysiology of pAF. Accordingly, in this Review, we examine the available data on the electrophysiological basis for pAF occurrence and maintenance, as well as the molecular mechanisms forming the underlying substrate. We first consider the mechanistic insights that have been obtained from clinical studies in the electrophysiology laboratory, noninvasive observations, and genetic studies. We then discuss the information about underlying molecular mechanisms that has been obtained from experimental studies on animal models and patient samples. Finally, we discuss the data available from animal models with spontaneous AF presentation, their relationship to clinical findings, and their relevance to understanding the mechanisms underlying pAF. Our analysis then turns to potential factors governing cases of progression from pAF to persistent AF and the clinical implications of the basic mechanisms we review. We conclude by identifying and discussing questions that we consider particularly important to address through future research in this area.
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Abbott GW. KCNE4 and KCNE5: K(+) channel regulation and cardiac arrhythmogenesis. Gene 2016; 593:249-60. [PMID: 27484720 DOI: 10.1016/j.gene.2016.07.069] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 07/23/2016] [Accepted: 07/28/2016] [Indexed: 12/14/2022]
Abstract
KCNE proteins are single transmembrane-segment voltage-gated potassium (Kv) channel ancillary subunits that exhibit a diverse range of physiological functions. Human KCNE gene mutations are associated with various pathophysiological states, most notably cardiac arrhythmias. Of the five isoforms in the human KCNE gene family, KCNE4 and the X-linked KCNE5 are, to date, the least-studied. Recently, however, interest in these neglected genes has been stoked by their putative association with debilitating or lethal cardiac arrhythmias. The sometimes-overlapping functional effects of KCNE4 and KCNE5 vary depending on both their Kv α subunit partner and on other ancillary subunits within the channel complex, but mostly fall into two contrasting categories - either inhibition, or fine-tuning of gating kinetics. This review covers current knowledge regarding the molecular mechanisms of KCNE4 and KCNE5 function, human disease associations, and findings from very recent studies of cardiovascular pathophysiology in Kcne4(-/-) mice.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Dept. of Pharmacology and Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA.
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Abstract
Atrial fibrillation (AF) is associated with increased morbidity and mortality. Atrial-selective potassium (K(+)) channel blockers may represent a novel therapeutic target. The best validated atrial-specific ion currents are the acetylcholine-activated inward-rectifier K(+) current IK,ACh and ultrarapidly activating delayed-rectifier K(+) current IKur. Two-pore domain and small-conductance Ca(2+)-activated K(+) channels and Kv1.1 channels may also contribute to the atrial repolarization. We review the molecular and electrophysiologic characteristics of atrial-selective K(+) channels and their potential pathophysiologic role in AF. We summarize currently available K(+) channel blockers focusing on the most important compounds.
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Affiliation(s)
- Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Hufelandstr. 55, Essen 45122, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Hufelandstr. 55, Essen 45122, Germany.
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Ovsepian SV, LeBerre M, Steuber V, O'Leary VB, Leibold C, Oliver Dolly J. Distinctive role of KV1.1 subunit in the biology and functions of low threshold K+ channels with implications for neurological disease. Pharmacol Ther 2016; 159:93-101. [DOI: 10.1016/j.pharmthera.2016.01.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Heijman J, Erfanian Abdoust P, Voigt N, Nattel S, Dobrev D. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation. J Physiol 2015; 594:537-53. [PMID: 26582329 DOI: 10.1113/jp271404] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/08/2015] [Indexed: 11/08/2022] Open
Abstract
The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and provide ideas about potential future directions.
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Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Pegah Erfanian Abdoust
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Stanley Nattel
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.,Department of Medicine, Montreal Heart Institute and Université de Montréal, Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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Heijman J, Algalarrondo V, Voigt N, Melka J, Wehrens XHT, Dobrev D, Nattel S. The value of basic research insights into atrial fibrillation mechanisms as a guide to therapeutic innovation: a critical analysis. Cardiovasc Res 2015; 109:467-79. [PMID: 26705366 DOI: 10.1093/cvr/cvv275] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023] Open
Abstract
Atrial fibrillation (AF) is an extremely common clinical problem associated with increased morbidity and mortality. Current antiarrhythmic options include pharmacological, ablation, and surgical therapies, and have significantly improved clinical outcomes. However, their efficacy remains suboptimal, and their use is limited by a variety of potentially serious adverse effects. There is a clear need for improved therapeutic options. Several decades of research have substantially expanded our understanding of the basic mechanisms of AF. Ectopic firing and re-entrant activity have been identified as the predominant mechanisms for arrhythmia initiation and maintenance. However, it has become clear that the clinical factors predisposing to AF and the cellular and molecular mechanisms involved are extremely complex. Moreover, all AF-promoting and maintaining mechanisms are dynamically regulated and subject to remodelling caused by both AF and cardiovascular disease. Accordingly, the initial presentation and clinical progression of AF patients are enormously heterogeneous. An understanding of arrhythmia mechanisms is widely assumed to be the basis of therapeutic innovation, but while this assumption seems self-evident, we are not aware of any papers that have critically examined the practical contributions of basic research into AF mechanisms to arrhythmia management. Here, we review recent insights into the basic mechanisms of AF, critically analyse the role of basic research insights in the development of presently used anti-AF therapeutic options and assess the potential value of contemporary experimental discoveries for future therapeutic innovation. Finally, we highlight some of the important challenges to the translation of basic science findings to clinical application.
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Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Vincent Algalarrondo
- Department of Medicine, Montreal Heart Institute and Université de Montréal, 5000 Belanger St. E., Montreal, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, D-45122 Essen, Germany
| | - Jonathan Melka
- Department of Medicine, Montreal Heart Institute and Université de Montréal, 5000 Belanger St. E., Montreal, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, D-45122 Essen, Germany
| | - Stanley Nattel
- Department of Medicine, Montreal Heart Institute and Université de Montréal, 5000 Belanger St. E., Montreal, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, D-45122 Essen, Germany
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