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Burnham HV, Cizauskas HE, Barefield DY. Fine tuning contractility: atrial sarcomere function in health and disease. Am J Physiol Heart Circ Physiol 2024; 326:H568-H583. [PMID: 38156887 DOI: 10.1152/ajpheart.00252.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
The molecular mechanisms of sarcomere proteins underlie the contractile function of the heart. Although our understanding of the sarcomere has grown tremendously, the focus has been on ventricular sarcomere isoforms due to the critical role of the ventricle in health and disease. However, atrial-specific or -enriched myofilament protein isoforms, as well as isoforms that become expressed in disease, provide insight into ways this complex molecular machine is fine-tuned. Here, we explore how atrial-enriched sarcomere protein composition modulates contractile function to fulfill the physiological requirements of atrial function. We review how atrial dysfunction negatively affects the ventricle and the many cardiovascular diseases that have atrial dysfunction as a comorbidity. We also cover the pathophysiology of mutations in atrial-enriched contractile proteins and how they can cause primary atrial myopathies. Finally, we explore what is known about contractile function in various forms of atrial fibrillation. The differences in atrial function in health and disease underscore the importance of better studying atrial contractility, especially as therapeutics currently in development to modulate cardiac contractility may have different effects on atrial sarcomere function.
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Affiliation(s)
- Hope V Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| | - Hannah E Cizauskas
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| | - David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
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Bizanti A, Zhang Y, Toledo Z, Bendowski KT, Harden SW, Mistareehi A, Chen J, Gozal D, Heal M, Christie R, Hunter PJ, Paton JFR, Cheng ZJ. Chronic intermittent hypoxia remodels catecholaminergic nerve innervation in mouse atria. J Physiol 2024; 602:49-71. [PMID: 38156943 PMCID: PMC10842556 DOI: 10.1113/jp284961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 10/04/2023] [Indexed: 01/03/2024] Open
Abstract
Chronic intermittent hypoxia (CIH, a model for sleep apnoea) is a major risk factor for several cardiovascular diseases. Autonomic imbalance (sympathetic overactivity and parasympathetic withdrawal) has emerged as a causal contributor of CIH-induced cardiovascular disease. Previously, we showed that CIH remodels the parasympathetic pathway. However, whether CIH induces remodelling of the cardiac sympathetic innervation remains unknown. Mice (male, C57BL/6J, 2-3 months) were exposed to either room air (RA, 21% O2 ) or CIH (alternating 21% and 5.7% O2 , every 6 min, 10 h day-1 ) for 8-10 weeks. Flat-mounts of their left and right atria were immunohistochemically labelled for tyrosine hydroxylase (TH, a sympathetic marker). Using a confocal microscope (or fluorescence microscope) and Neurlocudia 360 digitization and tracing system, we scanned both the left and right atria and quantitatively analysed the sympathetic axon density in both groups. The segmentation data was mapped onto a 3D mouse heart scaffold. Our findings indicated that CIH significantly remodelled the TH immunoreactive (-IR) innervation of the atria by increasing its density at the sinoatrial node, the auricles and the major veins attached to the atria (P < 0.05, n = 7). Additionally, CIH increased the branching points of TH-IR axons and decreased the distance between varicosities. Abnormal patterns of TH-IR axons around intrinsic cardiac ganglia were also found following CIH. We postulate that the increased sympathetic innervation may further amplify the effects of enhanced CIH-induced central sympathetic drive to the heart. Our work provides an anatomical foundation for the understanding of CIH-induced autonomic imbalance. KEY POINTS: Chronic intermittent hypoxia (CIH, a model for sleep apnoea) causes sympathetic overactivity, cardiovascular remodelling and hypertension. We determined the effect of CIH on sympathetic innervation of the mouse atria. In vivo CIH for 8-10 weeks resulted in an aberrant axonal pattern around the principal neurons within intrinsic cardiac ganglia and an increase in the density, branching point, tortuosity of catecholaminergic axons and atrial wall thickness. Utilizing mapping tool available from NIH (SPARC) Program, the topographical distribution of the catecholaminergic innervation of the atria were integrated into a novel 3D heart scaffold for precise anatomical distribution and holistic quantitative comparison between normal and CIH mice. This work provides a unique neuroanatomical understanding of the pathophysiology of CIH-induced autonomic remodelling.
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Affiliation(s)
- Ariege Bizanti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Yuanyuan Zhang
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Zulema Toledo
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Kohlton T Bendowski
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Scott W Harden
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Anas Mistareehi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Jin Chen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - David Gozal
- Joan C. Edwards School of medicine, Marshall University, Huntington, WV, USA
| | - Maci Heal
- MBF Bioscience, Williston, Vermont, USA
| | - Richard Christie
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peter J Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Julian F R Paton
- Department Physiology, Manaaki Manawa-the Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Zixi Jack Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
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Kanaporis G, Blatter LA. Increased Risk for Atrial Alternans in Rabbit Heart Failure: The Role of Ca 2+/Calmodulin-Dependent Kinase II and Inositol-1,4,5-trisphosphate Signaling. Biomolecules 2023; 14:53. [PMID: 38254653 PMCID: PMC10813785 DOI: 10.3390/biom14010053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/18/2023] [Accepted: 12/23/2023] [Indexed: 01/24/2024] Open
Abstract
Heart failure (HF) increases the probability of cardiac arrhythmias, including atrial fibrillation (AF), but the mechanisms linking HF to AF are poorly understood. We investigated disturbances in Ca2+ signaling and electrophysiology in rabbit atrial myocytes from normal and failing hearts and identified mechanisms that contribute to the higher risk of atrial arrhythmias in HF. Ca2+ transient (CaT) alternans-beat-to-beat alternations in CaT amplitude-served as indicator of increased arrhythmogenicity. We demonstrate that HF atrial myocytes were more prone to alternans despite no change in action potentials duration and only moderate decrease of L-type Ca2+ current. Ca2+/calmodulin-dependent kinase II (CaMKII) inhibition suppressed CaT alternans. Activation of IP3 signaling by endothelin-1 (ET-1) and angiotensin II (Ang II) resulted in acute, but transient reduction of CaT amplitude and sarcoplasmic reticulum (SR) Ca2+ load, and lowered the alternans risk. However, prolonged exposure to ET-1 and Ang II enhanced SR Ca2+ release and increased the degree of alternans. Inhibition of IP3 receptors prevented the transient ET-1 and Ang II effects and by itself increased the degree of CaT alternans. Our data suggest that activation of CaMKII and IP3 signaling contribute to atrial arrhythmogenesis in HF.
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Affiliation(s)
| | - Lothar A. Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, IL 60612, USA;
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Barefield DY, Tonino P, Woulfe KC, Rahmanseresht S, O’Leary TS, Burnham HV, Wasserstrom JA, Kirk JA, Previs MJ, Granzier HL, McNally EM. Myosin-binding protein H-like regulates myosin-binding protein distribution and function in atrial cardiomyocytes. Proc Natl Acad Sci U S A 2023; 120:e2314920120. [PMID: 38091294 PMCID: PMC10741380 DOI: 10.1073/pnas.2314920120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/25/2023] [Indexed: 12/18/2023] Open
Abstract
Mutations in atrial-enriched genes can cause a primary atrial myopathy that can contribute to overall cardiovascular dysfunction. MYBPHL encodes myosin-binding protein H-like (MyBP-HL), an atrial sarcomere protein that shares domain homology with the carboxy-terminus of cardiac myosin-binding protein-C (cMyBP-C). The function of MyBP-HL and the relationship between MyBP-HL and cMyBP-C is unknown. To decipher the roles of MyBP-HL, we used structured illumination microscopy, immuno-electron microscopy, and mass spectrometry to establish the localization and stoichiometry of MyBP-HL. We found levels of cMyBP-C, a major regulator of myosin function, were half as abundant compared to levels in the ventricle. In genetic mouse models, loss of MyBP-HL doubled cMyBP-C abundance in the atria, and loss of cMyBP-C doubled MyBP-HL abundance in the atria. Structured illumination microscopy showed that both proteins colocalize in the C-zone of the A-band, with MyBP-HL enriched closer to the M-line. Immuno-electron microscopy of mouse atria showed MyBP-HL strongly localized 161 nm from the M-line, consistent with localization to the third 43 nm repeat of myosin heads. Both cMyBP-C and MyBP-HL had less-defined sarcomere localization in the atria compared to ventricle, yet areas with the expected 43 nm repeat distance were observed for both proteins. Isometric force measurements taken from control and Mybphl null single atrial myofibrils revealed that loss of Mybphl accelerated the linear phase of relaxation. These findings support a mechanism where MyBP-HL regulates cMyBP-C abundance to alter the kinetics of sarcomere relaxation in atrial sarcomeres.
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Affiliation(s)
- David Y. Barefield
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Paola Tonino
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO80045
| | - Sheema Rahmanseresht
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Hope V. Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - J. Andrew Wasserstrom
- Department of Medicine and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Jonathan A. Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL60153
| | - Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT01655
| | - Henk L. Granzier
- Department of Cell and Molecular Medicine, University of Arizona, Tucson, AZ85724
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
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Keidar N, Peretz NK, Yaniv Y. Ca 2+ pushes and pulls energetics to maintain ATP balance in atrial cells: computational insights. Front Physiol 2023; 14:1231259. [PMID: 37528893 PMCID: PMC10387757 DOI: 10.3389/fphys.2023.1231259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 07/03/2023] [Indexed: 08/03/2023] Open
Abstract
To maintain atrial function, ATP supply-to-demand matching must be tightly controlled. Ca2+ can modulate both energy consumption and production. In light of evidence suggesting that Ca2+ affects energetics through "push" (activating metabolite flux and enzymes in the Krebs cycle to push the redox flux) and "pull" (acting directly on ATP synthase and driving the redox flux through the electron transport chain and increasing ATP production) pathways, we investigated whether both pathways are necessary to maintain atrial ATP supply-to-demand matching. Rabbit right atrial cells were electrically stimulated at different rates, and oxygen consumption and flavoprotein fluorescence were measured. To gain mechanistic insight into the regulators of ATP supply-to-demand matching in atrial cells, models of atrial electrophysiology, Ca2+ cycling and force were integrated with a model of mitochondrial Ca2+ and a modified model of mitochondrial energy metabolism. The experimental results showed that oxygen consumption increased in response to increases in the electrical stimulation rate. The model reproduced these findings and predicted that the increase in oxygen consumption is associated with metabolic homeostasis. The model predicted that Ca2+ must act both in "push" and "pull" pathways to increase oxygen consumption. In contrast to ventricular trabeculae, no rapid time-dependent changes in mitochondrial flavoprotein fluorescence were measured upon an abrupt change in workload. The model reproduced these findings and predicted that the maintenance of metabolic homeostasis is due to the effects of Ca2+ on ATP production. Taken together, this work provides evidence of Ca2+ "push" and "pull" activity to maintain metabolic homeostasis in atrial cells.
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Bizanti A, Zhang Y, Harden SW, Chen J, Hoover DB, Gozal D, Shivkumar K, Cheng ZJ. Catecholaminergic axon innervation and morphology in flat-mounts of atria and ventricles of mice. J Comp Neurol 2023; 531:596-617. [PMID: 36591925 PMCID: PMC10499115 DOI: 10.1002/cne.25444] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 01/03/2023]
Abstract
Sympathetic efferent axons regulate cardiac functions. However, the topographical distribution and morphology of cardiac sympathetic efferent axons remain insufficiently characterized due to the technical challenges involved in immunohistochemical labeling of the thick walls of the whole heart. In this study, flat-mounts of the left and right atria and ventricles of FVB mice were immunolabeled for tyrosine hydroxylase (TH), a marker of sympathetic nerves. Atrial and ventricular flat-mounts were scanned using a confocal microscope to construct montages. We found (1) In the atria: A few large TH-immunoreactive (IR) axon bundles entered both atria, branched into small bundles and then single axons that eventually formed very dense terminal networks in the epicardium, myocardium and inlet regions of great vessels to the atria. Varicose TH-IR axons formed close contact with cardiomyocytes, vessels, and adipocytes. Multiple intrinsic cardiac ganglia (ICG) were identified in the epicardium of both atria, and a subpopulation of the neurons in the ICG were TH-IR. Most TH-IR axons in bundles traveled through ICG before forming dense varicose terminal networks in cardiomyocytes. We did not observe varicose TH-IR terminals encircling ICG neurons. (2) In the left and right ventricles and interventricular septum: TH-IR axons formed dense terminal networks in the epicardium, myocardium, and vasculature. Collectively, TH labeling is achievable in flat-mounts of thick cardiac walls, enabling detailed mapping of catecholaminergic axons and terminal structures in the whole heart at single-cell/axon/varicosity scale. This approach provides a foundation for future quantification of the topographical organization of the cardiac sympathetic innervation in different pathological conditions.
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Affiliation(s)
- Ariege Bizanti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Yuanyuan Zhang
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Scott W Harden
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Jin Chen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Donald B Hoover
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - David Gozal
- Department of Child Health and Child Health Research Institute, and Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Kalyanam Shivkumar
- Department of Medicine, Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, University of California, Los Angeles, California, USA
| | - Zixi Jack Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
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Cros C, Douard M, Chaigne S, Pasqualin C, Bru-Mercier G, Recalde A, Pascarel-Auclerc C, Hof T, Haïssaguerre M, Hocini M, Jaïs P, Bernus O, Brette F. Regional Differences in Ca(2+) Signaling and Transverse-Tubules across Left Atrium from Adult Sheep. Int J Mol Sci 2023; 24. [PMID: 36768669 DOI: 10.3390/ijms24032347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
Cardiac excitation-contraction coupling can be different between regions of the heart. Little is known at the atria level, specifically in different regions of the left atrium. This is important given the role of cardiac myocytes from the pulmonary vein sleeves, which are responsible for ectopic activity during atrial fibrillation. In this study, we present a new method to isolate atrial cardiac myocytes from four different regions of the left atrium of a large animal model, sheep, highly relevant to humans. Using collagenase/protease we obtained calcium-tolerant atrial cardiac myocytes from the epicardium, endocardium, free wall and pulmonary vein regions. Calcium transients were slower (time to peak and time to decay) in free wall and pulmonary vein myocytes compared to the epicardium and endocardium. This is associated with lower t-tubule density. Overall, these results suggest regional differences in calcium transient and t-tubule density across left atria, which may play a major role in the genesis of atrial fibrillation.
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Yu XY, Shi JW, Rong YS, Chen YL, Liu TW, Zang YR, Fu ZA, Zhang JM, Han ZF, Liu ZG. The role of atria in ventricular fibrillation after continuous-flow left ventricular assist device implantation in ovine model. Front Cardiovasc Med 2023; 9:1000352. [PMID: 36698959 PMCID: PMC9868250 DOI: 10.3389/fcvm.2022.1000352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 12/19/2022] [Indexed: 01/11/2023] Open
Abstract
Objectives This study attempted to explore the hemodynamics and potential mechanisms driving pulmonary circulation in status of ventricular fibrillation (VF) following continuous-flow left ventricular assist device (CF-LVAD) implantation. Methods An ovine CF-LVAD model was built in small-tailed Han sheep, with the pump speed set as 2,400 rpm. VF was induced following ventricular tachycardia using a temporary pacemaker probe to stimulate the right and left ventricular free walls. The central venous pressure (CVP), pump flow (PF), pulmonary artery flow (PAF) and other major indicators were observed and recorded after VF. Results Low-flow systemic and pulmonary circulation could be sustained for 60 min under VF with sinus atrial rhythm after CF-LVAD implantation. The CVP gradually increased. The mean PF declined from 1.80 to 1.20 L/min, and the mean PAF decreased from 1.62 L/min to 0.87 L/min. Under VF with atrial fibrillation, the systemic and pulmonary circulation couldn't be sustained. The CVP jumped from the 5 mmHg baseline to 12 mmHg, the mean PF rapidly decreased from 3.45 L/min to 0.79 L/min, and the PAF declined from 3.94 L/min to 0.77 L/min. Conclusion The atrial rhythm and function might be essential for the circulation maintenance in patients with VF after CF-LVAD implantation.
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Affiliation(s)
- Xin-Yi Yu
- Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Jian-Wei Shi
- Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Yan-Sheng Rong
- Department of Anesthesiology, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Yuan-Lu Chen
- Department of Cardiac Electrophysiology, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Tian-Wen Liu
- Laboratory Animal Center, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Yi-Rui Zang
- Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Ze-An Fu
- Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China,Cardiovascular Clinical College of Tianjin Medical University, Tianjin, China
| | - Jie-Min Zhang
- Laboratory Animal Center, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Zhi-Fu Han
- ROCOR Medical Technology Co., Ltd., Tianjin, China
| | - Zhi-Gang Liu
- Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China,Cardiovascular Clinical College of Tianjin Medical University, Tianjin, China,*Correspondence: Zhi-Gang Liu,
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Zhang X, Smith CER, Morotti S, Edwards AG, Sato D, Louch WE, Ni H, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: II Ca 2+ -handling protein variation. J Physiol 2022:10.1113/JP283602. [PMID: 36114707 PMCID: PMC10017376 DOI: 10.1113/jp283602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Disruption of the transverse-axial tubule system (TATS) in diseases such as heart failure and atrial fibrillation occurs in combination with changes in the expression and distribution of key Ca2+ -handling proteins. Together this ultrastructural and ionic remodelling is associated with aberrant Ca2+ cycling and electrophysiological instabilities that underlie arrhythmic activity. However, due to the concurrent changes in TATs and Ca2+ -handling protein expression and localization that occur in disease it is difficult to distinguish their individual contributions to the arrhythmogenic state. To investigate this, we applied our novel 3D human atrial myocyte model with spatially detailed Ca2+ diffusion and TATS to investigate the isolated and interactive effects of changes in expression and localization of key Ca2+ -handling proteins and variable TATS density on Ca2+ -handling abnormality driven membrane instabilities. We show that modulating the expression and distribution of the sodium-calcium exchanger, ryanodine receptors and the sarcoplasmic reticulum (SR) Ca2+ buffer calsequestrin have varying pro- and anti-arrhythmic effects depending on the balance of opposing influences on SR Ca2+ leak-load and Ca2+ -voltage relationships. Interestingly, the impact of protein remodelling on Ca2+ -driven proarrhythmic behaviour varied dramatically depending on TATS density, with intermediately tubulated cells being more severely affected compared to detubulated and densely tubulated myocytes. This work provides novel mechanistic insight into the distinct and interactive consequences of TATS and Ca2+ -handling protein remodelling that underlies dysfunctional Ca2+ cycling and electrophysiological instability in disease. KEY POINTS: In our companion paper we developed a 3D human atrial myocyte model, coupling electrophysiology and Ca2+ handling with subcellular spatial details governed by the transverse-axial tubule system (TATS). Here we utilize this model to mechanistically examine the impact of TATS loss and changes in the expression and distribution of key Ca2+ -handling proteins known to be remodelled in disease on Ca2+ homeostasis and electrophysiological stability. We demonstrate that varying the expression and localization of these proteins has variable pro- and anti-arrhythmic effects with outcomes displaying dependence on TATS density. Whereas detubulated myocytes typically appear unaffected and densely tubulated cells seem protected, the arrhythmogenic effects of Ca2+ handling protein remodelling are profound in intermediately tubulated cells. Our work shows the interaction between TATS and Ca2+ -handling protein remodelling that underlies the Ca2+ -driven proarrhythmic behaviour observed in atrial fibrillation and may help to predict the effects of antiarrhythmic strategies at varying stages of ultrastructural remodelling.
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Affiliation(s)
- Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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Cantinotti M, Marchese P, Scalese M, Franchi E, Assanta N, Koestenberger M, Pizzuto A, Pak V, Santoro G, Jani V, Kutty S, Giordano R. Atrial Function Impairments after Pediatric Cardiac Surgery Evaluated by STE Analysis. J Clin Med 2022; 11. [PMID: 35566624 DOI: 10.3390/jcm11092497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/24/2022] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
Background: Applications of atrial speckle tracking echocardiography (STE) strain (ε) analysis in pediatric cardiac surgery have been limited. This study aims to evaluate the feasibility of atrial STE ε analysis and the progression of atrial ε values as a function of post-operative time in children after pediatric cardiac surgery. Methods: 131 children (mean 1.69 ± 2.98; range 0.01−15.16 years) undergoing cardiac surgery were prospectively enrolled. Echocardiographic examinations were performed pre-operatively and at 3 different post-operative intervals: Time 1 (24−36 h), Time 2 (3−5 days), Time 3 (>5 days, before discharging). The right and left atrium longitudinal systolic contractile (Ct), Conduit (Cd), and Reservoir (R) ε were evaluated with a novel atrial specific software with both P- and R-Gating methods. One hundred and thirty-one age-matched normal subjects (mean 1.7 ± 3.2 years) were included as controls. Results: In all, 309 examinations were performed over the post-operative times. For each post-operative interval, all STE atrial ε parameters assessed were significantly lower compared to controls (all p < 0.0001). The lowest atrial ε values were found at Time 1, with only partial recovery thereafter (p from 0.02 to 0.04). All atrial ε values at discharge were decreased compared to the controls (all p < 0.0001). Significant correlations of the atrial ε values with cardio-pulmonary-bypass time, left and right ventricular ε values (p < 0.05), and ejection fraction (p < 0.05) were demonstrated. Conclusions: Atrial ε is highly reduced after surgery with only partial post-operative recovery in the near term. Our study additionally demonstrates that post-surgical atrial and ventricular ε responses correlated with each other.
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11
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Wu L, Fiet MD, Raaijmakers DR, Woudstra L, van Rossum AC, Niessen HWM, Krijnen PAJ. Transient atrial inflammation in a murine model of Coxsackievirus B3-induced myocarditis. Int J Exp Pathol 2022; 103:149-155. [PMID: 35363404 PMCID: PMC9264345 DOI: 10.1111/iep.12438] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/21/2022] [Accepted: 03/06/2022] [Indexed: 12/02/2022] Open
Abstract
Atrial dysfunction is a relatively common complication of acute myocarditis, although its pathophysiology is unclear. There is limited information on myocarditis‐associated histological changes in the atria and how they develop in time. The aim of this study therefore was to investigate inflammation, fibrosis and viral genome in the atria in time after mild CVB3‐induced viral myocarditis (VM) in mice. C3H mice (n = 68) were infected with 105 PFU of Coxsackievirus B3 (CVB3) and were compared with uninfected mice (n = 10). Atrial tissue was obtained at days 4, 7, 10, 21, 35 or 49 post‐infection. Cellular infiltration of CD45+ lymphocytes, MAC3+ macrophages, Ly6G+ neutrophils and mast cells was quantified by (immuno)histochemical staining. The CVB3 RNA was determined by in situ hybridization, and fibrosis was evaluated by elastic van Gieson (EvG) staining. In the atria of VM mice, the numbers of lymphocytes on days 4 and 7 (p < .05) and days 10 (p < .01); macrophages on days 7 (p < .01) and 10 (p < .05); neutrophils on days 4 (p < .05); and mast cells on days 4 and 7 (p < .05) increased significantly compared with control mice and decreased thereafter to basal levels. No cardiomyocyte death was observed, and the CVB3 genome was detected in only one infected mouse on Day 4 post‐infection. No significant changes in the amount of atrial fibrosis were found between VM and control mice. A temporary increase in inflammation is induced in the atria in the acute phase of CVB3‐induced mild VM, which may facilitate the development of atrial arrhythmia and contractile dysfunction.
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Affiliation(s)
- Linghe Wu
- Department of Pathology, Amsterdam University Medical Centers, location VUmc, Amsterdam, The Netherlands.,Department of Pathology, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Mitchell D Fiet
- Department of Pathology, Amsterdam University Medical Centers, location VUmc, Amsterdam, The Netherlands.,Department of Pathology, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Daan R Raaijmakers
- Department of Pathology, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Linde Woudstra
- Department of Reproductive Medicine, Reinier de Graaf Hospital, Voorburg, The Netherlands
| | - Albert C van Rossum
- Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.,Department of Cardiac Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands.,Department of Cardiology, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
| | - Hans W M Niessen
- Department of Pathology, Amsterdam University Medical Centers, location VUmc, Amsterdam, The Netherlands.,Department of Pathology, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.,Department of Cardiology, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
| | - Paul A J Krijnen
- Department of Pathology, Amsterdam University Medical Centers, location VUmc, Amsterdam, The Netherlands.,Department of Pathology, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands.,Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
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12
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Martinez‐Hernandez E, Blatter LA, Kanaporis G. L-type Ca 2+ channel recovery from inactivation in rabbit atrial myocytes. Physiol Rep 2022; 10:e15222. [PMID: 35274829 PMCID: PMC8915713 DOI: 10.14814/phy2.15222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/07/2022] [Accepted: 02/16/2022] [Indexed: 01/27/2023]
Abstract
Adaptation of the myocardium to varying workloads critically depends on the recovery from inactivation (RFI) of L-type Ca2+ channels (LCCs) which provide the trigger for cardiac contraction. The goal of the present study was a comprehensive investigation of LCC RFI in atrial myocytes. The study was performed on voltage-clamped rabbit atrial myocytes using a double pulse protocol with variable diastolic intervals in cells held at physiological holding potentials, with intact intracellular Ca2+ release, and preserved Na+ current and Na+ /Ca2+ exchanger (NCX) activity. We demonstrate that the kinetics of RFI of LCCs are co-regulated by several factors including resting membrane potential, [Ca2+ ]i , Na+ influx, and activity of CaMKII. In addition, activation of CaMKII resulted in increased ICa amplitude at higher pacing rates. Pharmacological inhibition of NCX failed to have any significant effect on RFI, indicating that impaired removal of Ca2+ by NCX has little effect on LCC recovery. Finally, RFI of intracellular Ca2+ release was substantially slower than LCC RFI, suggesting that inactivation kinetics of LCC do not significantly contribute to the beat-to-beat refractoriness of SR Ca2+ release. The study demonstrates that CaMKII and intracellular Ca2+ dynamics play a central role in modulation of LCC activity in atrial myocytes during increased workloads that could have important consequences under pathological conditions such as atrial fibrillations, where Ca2+ cycling and CaMKII activity are altered.
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Affiliation(s)
| | - Lothar A. Blatter
- Department of Physiology & BiophysicsRush University Medical CenterChicagoIllinoisUSA
| | - Giedrius Kanaporis
- Department of Physiology & BiophysicsRush University Medical CenterChicagoIllinoisUSA
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13
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Lang D, Medvedev RY, Ratajczyk L, Zheng J, Yuan X, Lim E, Han OY, Valdivia HH, Glukhov AV. Region-specific distribution of transversal-axial tubule system organization underlies heterogeneity of calcium dynamics in the right atrium. Am J Physiol Heart Circ Physiol 2022; 322:H269-H284. [PMID: 34951544 PMCID: PMC8782648 DOI: 10.1152/ajpheart.00381.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The atrial myocardium demonstrates the highly heterogeneous organization of the transversal-axial tubule system (TATS), although its anatomical distribution and region-specific impact on Ca2+ dynamics remain unknown. Here, we developed a novel method for high-resolution confocal imaging of TATS in intact live mouse atrial myocardium and applied a custom-developed MATLAB-based computational algorithm for the automated analysis of TATS integrity. We observed a twofold higher (P < 0.01) TATS density in the right atrial appendage (RAA) than in the intercaval regions (ICR, the anatomical region between the superior vena cava and atrioventricular junction and between the crista terminalis and interatrial septum). Whereas RAA predominantly consisted of well-tubulated myocytes, ICR showed partially tubulated/untubulated cells. Similar TATS distribution was also observed in healthy human atrial myocardium sections. In both mouse atrial preparations and isolated mouse atrial myocytes, we observed a strong anatomical correlation between TATS distribution and Ca2+ transient synchronization and rise-up time. This region-specific difference in Ca2+ transient morphology disappeared after formamide-induced detubulation. ICR myocytes showed a prolonged action potential duration at 80% of repolarization as well as a significantly lower expression of RyR2 and Cav1.2 proteins but similar levels of NCX1 and Cav1.3 compared with RAA tissue. Our findings provide a detailed characterization of the region-specific distribution of TATS in mouse and human atrial myocardium, highlighting the structural foundation for anatomical heterogeneity of Ca2+ dynamics and contractility in the atria. These results could indicate different roles of TATS in Ca2+ signaling at distinct anatomical regions of the atria and provide mechanistic insight into pathological atrial remodeling.NEW & NOTEWORTHY Mouse and human atrial myocardium demonstrate high variability in the organization of the transversal-axial tubule system (TATS), with more organized TATS expressed in the right atrial appendage. TATS distribution governs anatomical heterogeneity of Ca2+ dynamics and thus could contribute to integral atrial contractility, mechanics, and arrhythmogenicity.
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Affiliation(s)
- Di Lang
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Roman Y Medvedev
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Lucas Ratajczyk
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Jingjing Zheng
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Xiaoyu Yuan
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Evi Lim
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Owen Y Han
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Hector H Valdivia
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Alexey V Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
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14
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Kim HY, Ahn YM, Na SW, Jang YJ, Kang DG, Lee HS, Cho KW. Oryeongsan (Wulingsan) ameliorates impaired ANP secretion of atria from spontaneously hypertensive rats. Biomed Pharmacother 2022; 146:112433. [PMID: 35062052 DOI: 10.1016/j.biopha.2021.112433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/02/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
Oryeongsan (ORS), a herbal medicine formula, has long been used for the treatment of impaired body water balance in Asian countries. Recently, it was shown that ORS administration modulates the renin-angiotensin system (RAS). Purpose of the present study was to determine characteristics of atrial ANP secretion and effects of ORS on the secretion in the atria from spontaneously hypertensive rats (SHR). Normotensive WKY groups (WKY-V, WKY-ORS, WKY-LOS) and hypertensive SHR groups (SHR-V, SHR-ORS, SHR-LOS) treated with vehicle, ORS, and losartan as a positive control group, respectively, were used. Experiments were performed in perfused beating atria (1.3 Hz) allowing atrial distension, acetylcholine (ACh) stimulation, and serial collection of atrial perfusates. The secreted ANP concentration was measured using radioimmunoassay. Interstitial fluid (ISF) translocation was measured using [3H]inulin clearance. Stepwise increase in atrial distension by 1.1, 2.0, and 2.7 cmH2O above basal distension further increased ANP secretion proportionally in the atria from WKY-V, but the response was significantly suppressed in the atria from SHR-V. Cardiomyocyte ANP release, the first step of atrial ANP secretion, was suppressed in the atria from SHR-V compared to those from WKY-V (-8.02 ± 2.86, -15.86 ± 2.27, and -20.09 ± 3.62%; n = 8, for SHR-V vs. 8.59 ± 2.81, 15.65 ± 7.14, and 38.12 ± 8.28%; n = 8, for WKY-V; p < 0.001 for all stepwise distension, respectively). Chronic treatment with ORS reversed the suppressed ANP release in atria from SHR-ORS group (6.76 ± 3.92, 9.12 ± 2.85, and 28.79 ± 1.79% for SHR-ORS; n = 5 vs. SHR-V; n = 8; p = 0.01, p < 0.001, p < 0.001, respectively). The effects of ORS were comparable to those of losartan. Trans-endocardial translocation of ISF, the second step of atrial ANP secretion was similar in the atria from the hypertensive SHR-V and normotensive WKY-V. ACh-induced ANP secretion and cardiomyocyte ANP release were also suppressed in the atria from SHR-V compared to WKY-V and ORS reversed the suppression. These findings were accompanied with accentuation of the AT1 receptor expression and suppression of the AT2/Mas receptor, M2 mACh receptor and GIRK4, a molecular component of KACh channel, expression in the atria from SHR-V. Further, treatment with ORS or losartan reversed the expressions in the groups of SHR-ORS and SHR-LOS. These results show that ANP secretion is suppressed in the atria from SHR in association with accentuation of AT1 receptor and suppression of AT2/Mas receptor and KACh channel expression. Treatment with ORS ameliorates impaired ANP secretion through improving cardiomyocyte ANP release with modulation of the cardiac RAS and muscarinic signaling. These findings provide experimental evidence which supports the effect of ORS on the regulation of atrial ANP secretion in the atria from SHR.
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Affiliation(s)
- Hye Yoom Kim
- Hanbang Cardio-Renal Syndrome Research Center, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea; College of Korean Medicine and Professional Graduate School of Korean Medicine, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea.
| | - You Mee Ahn
- Clinical Medicine Division, Korea Institute of Oriental Medicine, 1672, Yuseong-daero, Daejeon, Republic of Korea.
| | - Se Won Na
- Hanbang Cardio-Renal Syndrome Research Center, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea; College of Korean Medicine and Professional Graduate School of Korean Medicine, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea.
| | - Youn Jae Jang
- Hanbang Cardio-Renal Syndrome Research Center, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea; College of Korean Medicine and Professional Graduate School of Korean Medicine, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea.
| | - Dae Gill Kang
- Hanbang Cardio-Renal Syndrome Research Center, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea; College of Korean Medicine and Professional Graduate School of Korean Medicine, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea.
| | - Ho Sub Lee
- Hanbang Cardio-Renal Syndrome Research Center, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea; College of Korean Medicine and Professional Graduate School of Korean Medicine, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea.
| | - Kyung Woo Cho
- Hanbang Cardio-Renal Syndrome Research Center, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea; College of Korean Medicine and Professional Graduate School of Korean Medicine, Wonkwang University, 460, Iksan-daero, Iksan, Jeonbuk, Republic of Korea.
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15
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Roney CH, Sillett C, Whitaker J, Lemus JAS, Sim I, Kotadia I, O'Neill M, Williams SE, Niederer SA. Applications of multimodality imaging for left atrial catheter ablation. Eur Heart J Cardiovasc Imaging 2021; 23:31-41. [PMID: 34747450 PMCID: PMC8685603 DOI: 10.1093/ehjci/jeab205] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Atrial arrhythmias, including atrial fibrillation and atrial flutter, may be treated through catheter ablation. The process of atrial arrhythmia catheter ablation, which includes patient selection, pre-procedural planning, intra-procedural guidance, and post-procedural assessment, is typically characterized by the use of several imaging modalities to sequentially inform key clinical decisions. Increasingly, advanced imaging modalities are processed via specialized image analysis techniques and combined with intra-procedural electrical measurements to inform treatment approaches. Here, we review the use of multimodality imaging for left atrial ablation procedures. The article first outlines how imaging modalities are routinely used in the peri-ablation period. We then describe how advanced imaging techniques may inform patient selection for ablation and ablation targets themselves. Ongoing research directions for improving catheter ablation outcomes by using imaging combined with advanced analyses for personalization of ablation targets are discussed, together with approaches for their integration in the standard clinical environment. Finally, we describe future research areas with the potential to improve catheter ablation outcomes.
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Affiliation(s)
- Caroline H Roney
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
| | - Charles Sillett
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
| | | | - Iain Sim
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
| | - Irum Kotadia
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
| | - Mark O'Neill
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
| | - Steven E Williams
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
- Centre for Cardiovascular Science, The University of Edinburgh, Scotland, UK
| | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College, London, UK
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16
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Okuno T, Lanz J, Stortecky S, Heg D, Bernhard B, Gräni C, Huber A, Praz F, Räber L, Valgimigli M, Siontis GCM, Windecker S, Pilgrim T. Clinical impact of left atrial appendage filling defects in patients undergoing transcatheter aortic valve implantation. Eur Heart J Cardiovasc Imaging 2021; 23:1354-1364. [PMID: 34463717 DOI: 10.1093/ehjci/jeab142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/07/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS Incidental detection of left atrial appendage (LAA) filling defects is a common finding on multi-detector computed tomography in aortic stenosis patients under evaluation for transcatheter aortic valve implantation (TAVI). We aimed to investigate the incidence of LAA filling defects before TAVI and its impact on clinical outcomes. METHODS AND RESULTS In a prospective registry, LAA filling defects were retrospectively evaluated and categorized into one of four sub-types: thrombus-like, heterogeneous, horizontal, and Hounsfield Unit (HU)-run-off. The primary endpoint was the composite of cardiovascular death or disabling stroke up to 1-year follow-up. Among 1621 patients undergoing TAVI between August 2007 and June 2018, LAA filling defects were present in 177 patients (11%), and categorized as thrombus-like in 22 (1.4%), heterogeneous in 37 (2.3%), horizontal in 80 (4.9%), and HU-run-off in 38 (2.4%). Compared to patients with normal LAA filling, patients with LAA filling defects had greater prevalence of atrial fibrillation (84.7% vs. 26.4%, P < 0.001) and history of cerebrovascular events (16.4% vs. 10.9%, P = 0.045). The primary endpoint occurred in 131 patients (9.2%) with normal LAA filling and in 36 patients (21.2%) with LAA filling defects (P < 0.001). Subgroup analysis suggested that the risk of disabling stroke was greatest in the thrombus-like pattern (23.0%), followed by the HU-run-off (8.0%), the heterogeneous (6.2%), and the horizontal pattern (1.2%). CONCLUSION LAA filling defects were observed in 11% of aortic stenosis patients undergoing TAVI and associated with an increased risk of cardiovascular death and disabling stroke up to 1 year following TAVI. TRIAL REGISTRATION https://www.clinicaltrials.gov. NCT01368250.
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Affiliation(s)
- Taishi Okuno
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Jonas Lanz
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Stefan Stortecky
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Dik Heg
- Clinical Trials Unit Bern, University of Bern, Bern, Switzerland
| | - Benedikt Bernhard
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Christoph Gräni
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Adrian Huber
- Department of Diagnostic, Interventional and Pediatric Radiology, Inselspital, University of Bern, Bern, Switzerland
| | - Fabien Praz
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Lorenz Räber
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Marco Valgimigli
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - George C M Siontis
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Stephan Windecker
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
| | - Thomas Pilgrim
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, CH-3010 Bern, Switzerland
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17
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Weresa J, Pędzińska-Betiuk A, Schlicker E, Hirnle G, Mitrosz M, Malinowska B. Beneficial and harmful effects of CB 1 and CB 2 receptor antagonists on chronotropic and inotropic effects related to atrial β-adrenoceptor activation in humans and in rats with primary hypertension. Clin Exp Pharmacol Physiol 2021; 48:1547-1557. [PMID: 34333780 DOI: 10.1111/1440-1681.13560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 11/26/2022]
Abstract
We have previously shown that cannabinoid CB1 and CB2 receptor antagonists, AM251 and AM630, respectively, modulate cardiostimulatory effects of isoprenaline in atria of Wistar rats. The aim of the present study was to examine whether such modulatory effects can also be observed (a) in the human atrium and (b) in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Inotropic effects of isoprenaline and/or CGP12177 (that activate the high- and low-affinity site of β1 -adrenoceptors, respectively) were examined in paced human atrial trabeculae and rat left atria; chronotropic effects were studied in spontaneously beating right rat atria. AM251 modified cardiostimulatory effects more strongly than AM630. Therefore, AM251 (1 μM) enhanced the chronotropic effect of isoprenaline in WKY and SHR as well as inotropic action of isoprenaline in WKY and in human atria. It also increased the inotropic influence of CGP12177 in SHR. AM630 (1 μM) decreased the inotropic effect of isoprenaline and CGP12177 in WKY, but enhanced the isoprenaline-induced inotropic effect in SHR and human atria. Furthermore, AM251 (0.1 and 3 μM) and AM630 (0.1 μM) reduced the inotropic action of isoprenaline in human atria. In conclusion, cannabinoid receptor antagonists have potentially harmful and beneficial effects through their amplificatory effects on β-adrenoceptor-mediated positive chronotropic and inotropic actions, respectively.
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Affiliation(s)
- Jolanta Weresa
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Białystok, Poland
| | - Anna Pędzińska-Betiuk
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Białystok, Poland
| | - Eberhard Schlicker
- Department of Pharmacology and Toxicology, University of Bonn, Bonn, Germany
| | - Grzegorz Hirnle
- Department of Cardiac Surgery, Medical University of Białystok, Białystok, Poland
| | - Maciej Mitrosz
- Department of Cardiac Surgery, Medical University of Białystok, Białystok, Poland
| | - Barbara Malinowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Białystok, Poland
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18
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Smirnova SL, Roshchevskaya IM. Depolarization of the Atrial Subepicardium in Rats with Experimentally Induced Pulmonary Hypertension. Bull Exp Biol Med 2021; 170:741-743. [PMID: 33893952 DOI: 10.1007/s10517-021-05145-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Indexed: 11/27/2022]
Abstract
Using an experimental model of pulmonary hypertension in rats (monocrotaline in a dose of 60 mg/kg), we revealed an additional focus of early excitation in the zone where the pulmonary veins enter the left atrium, in addition to the main focus in the sinoatrial node. Pulmonary hypertension leads to the formation of regions of early activation in the right and left atria and a significant change in the sequence of atrial depolarization. Propagation of independent excitation waves in the right and left atria increases heterogeneity of depolarization and leads to the formation of atrial arrhythmias.
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Affiliation(s)
- S L Smirnova
- Department of Comparative Cardiology, Federal Research Centre Komi Research Centre, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia.
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19
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Doria de Vasconcellos H, Post WS, Ervin AM, Haberlen SA, Budoff M, Malvestutto C, Magnani JW, Feinstein MJ, Brown TT, Lima JAC, Wu KC. Associations Between HIV Serostatus and Cardiac Structure and Function Evaluated by 2-Dimensional Echocardiography in the Multicenter AIDS Cohort Study. J Am Heart Assoc 2021; 10:e019709. [PMID: 33749311 PMCID: PMC8174316 DOI: 10.1161/jaha.120.019709] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Background We aimed to investigate whether there are differences in cardiac structure and systolic and diastolic function evaluated by 2‐dimensional echocardiography among men living with versus without HIV in the era of combination antiretroviral therapy. Methods and Results We performed a cross‐sectional analysis of 1195 men from MACS (Multicenter AIDS Cohort Study) who completed a transthoracic echocardiogram examination between 2017 and 2019. Associations between HIV serostatus and echocardiographic indices were assessed by multivariable regression analyses, adjusting for demographics and cardiovascular risk factors. Among men who are HIV+, associations between HIV disease severity markers and echocardiographic parameters were also investigated. Average age was 57.1±11.9 years; 29% of the participants were Black, and 55% were HIV+. Most men who were HIV+ (77%) were virally suppressed; 92% received combination antiretroviral therapy. Prevalent left ventricular (LV) systolic dysfunction (ejection fraction <50%) was low and HIV serostatus was not associated with left ventricular ejection fraction. Multivariable adjustment models showed that men who were HIV+ versus those who were HIV− had greater LV mass index and larger left atrial diameter and right ventricular (RV) end‐diastolic area; lower RV function; and higher prevalence of diastolic dysfunction. Higher current CD4+ T cell count ≥400 cell/mm3 versus <400 was associated with smaller LV diastolic volume and RV area. Virally suppressed men who were HIV+ versus those who were HIV− had higher indexed LV mass and left atrial areas and greater diastolic dysfunction. Conclusions HIV seropositivity was independently associated with greater LV mass index, left atrial and RV sizes, lower RV function and diastolic abnormalities, but not left ventricular ejection fraction, which may herald a future predisposition to heart failure with preserved ejection fraction among men living with HIV.
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Affiliation(s)
| | - Wendy S Post
- Johns Hopkins University School of Medicine Baltimore MD.,Johns Hopkins Bloomberg School of Public Health Baltimore MD
| | | | | | - Matthew Budoff
- Lundquist Institute at Harbor-UCLA Medical Center Los Angeles CA
| | | | | | - Matthew J Feinstein
- Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL
| | - Todd T Brown
- Johns Hopkins University School of Medicine Baltimore MD
| | - Joao A C Lima
- Johns Hopkins University School of Medicine Baltimore MD
| | - Katherine C Wu
- Johns Hopkins University School of Medicine Baltimore MD
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Simard C, Ferchaud V, Sallé L, Milliez P, Manrique A, Alexandre J, Guinamard R. TRPM4 Participates in Aldosterone-Salt-Induced Electrical Atrial Remodeling in Mice. Cells 2021; 10:636. [PMID: 33809210 PMCID: PMC7998432 DOI: 10.3390/cells10030636] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 12/20/2022] Open
Abstract
Aldosterone plays a major role in atrial structural and electrical remodeling, in particular through Ca2+-transient perturbations and shortening of the action potential. The Ca2+-activated non-selective cation channel Transient Receptor Potential Melastatin 4 (TRPM4) participates in atrial action potential. The aim of our study was to elucidate the interactions between aldosterone and TRPM4 in atrial remodeling and arrhythmias susceptibility. Hyperaldosteronemia, combined with a high salt diet, was induced in mice by subcutaneously implanted osmotic pumps during 4 weeks, delivering aldosterone or physiological serum for control animals. The experiments were conducted in wild type animals (Trpm4+/+) as well as Trpm4 knock-out animals (Trpm4-/-). The atrial diameter measured by echocardiography was higher in Trpm4-/- compared to Trpm4+/+ animals, and hyperaldosteronemia-salt produced a dilatation in both groups. Action potentials duration and triggered arrhythmias were measured using intracellular microelectrodes on the isolated left atrium. Hyperaldosteronemia-salt prolong action potential in Trpm4-/- mice but had no effect on Trpm4+/+ mice. In the control group (no aldosterone-salt treatment), no triggered arrythmias were recorded in Trpm4+/+ mice, but a high level was detected in Trpm4-/- mice. Hyperaldosteronemia-salt enhanced the occurrence of arrhythmias (early as well as delayed-afterdepolarization) in Trpm4+/+ mice but decreased it in Trpm4-/- animals. Atrial connexin43 immunolabelling indicated their disorganization at the intercalated disks and a redistribution at the lateral side induced by hyperaldosteronemia-salt but also by Trpm4 disruption. In addition, hyperaldosteronemia-salt produced pronounced atrial endothelial thickening in both groups. Altogether, our results indicated that hyperaldosteronemia-salt and TRPM4 participate in atrial electrical and structural remodeling. It appears that TRPM4 is involved in aldosterone-induced atrial action potential shortening. In addition, TRPM4 may promote aldosterone-induced atrial arrhythmias, however, the underlying mechanisms remain to be explored.
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Affiliation(s)
| | | | | | | | | | | | - Romain Guinamard
- EA 4650, Signalisation, Electrophysiologie et Imagerie des Lésions d’Ischémie-Reperfusion Myocardique, GIP Cyceron, Université de Caen Normandie, CHU de Caen, 14032 Caen, France; (C.S.); (V.F.); (L.S.); (P.M.); (A.M.); (J.A.)
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21
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Burton RAB, Terrar DA. Emerging Evidence for cAMP-calcium Cross Talk in Heart Atrial Nanodomains Where IP 3-Evoked Calcium Release Stimulates Adenylyl Cyclases. Contact (Thousand Oaks) 2021; 4:25152564211008341. [PMID: 37366374 PMCID: PMC10243587 DOI: 10.1177/25152564211008341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/01/2021] [Accepted: 03/07/2021] [Indexed: 06/28/2023]
Abstract
Calcium handling is vital to normal physiological function in the heart. Human atrial arrhythmias, eg. atrial fibrillation, are a major morbidity and mortality burden, yet major gaps remain in our understanding of how calcium signaling pathways function and interact. Inositol trisphosphate (IP3) is a calcium-mobilizing second messenger and its agonist-induced effects have been observed in many tissue types. In the atria IP3 receptors (IR3Rs) residing on junctional sarcoplasmic reticulum augment cellular calcium transients and, when over-stimulated, lead to arrhythmogenesis. Recent studies have demonstrated that the predominant pathway for IP3 actions in atrial myocytes depends on stimulation of calcium-dependent forms of adenylyl cyclase (AC8 and AC1) by IP3-evoked calcium release from the sarcoplasmic reticulum. AC8 shows co-localisation with IP3Rs and AC1 appears to be nearby. These observations support crosstalk between calcium and cAMP pathways in nanodomains in atria. Similar mechanisms also appear to operate in the pacemaker region of the sinoatrial node. Here we discuss these significant advances in our understanding of atrial physiology and pathology, together with implications for the identification of potential novel targets and modulators for the treatment of atrial arrhythmias.
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Affiliation(s)
| | - Derek A. Terrar
- Department of Pharmacology, University of Oxford, Oxford, UK
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22
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Smirnova SL, Roshchevskaya IM, Stolyaruk VN, Vititnova MB, Tsorin IB, Kryzhanovsky SA. Depolarization of the Rat Atria in Experimental Simulation of the Holiday Heart Syndrome. DOKL BIOCHEM BIOPHYS 2020; 495:304-306. [PMID: 33368040 DOI: 10.1134/s1607672920060149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 11/23/2022]
Abstract
In the study of the sequence of depolarization of the atrial subepicardium of rats in the short-term alcohol consumption model (the "Holiday heart" syndrome), the localization of the sources of atrial arrhythmias was determined for the first time. The difference in the excitation of the right and left atria was discovered: the right atrium is activated anterogradely from the sinoatrial node, whereas the left atrium is activated retrogradely from the ectopic focus located in the left auricular appendage.
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Affiliation(s)
- S L Smirnova
- Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | | | - V N Stolyaruk
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - M B Vititnova
- Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - I B Tsorin
- Zakusov Research Institute of Pharmacology, Moscow, Russia
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23
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Nollet EE, Manders EM, Goebel M, Jansen V, Brockmann C, Osinga J, van der Velden J, Helmes M, Kuster DWD. Large-Scale Contractility Measurements Reveal Large Atrioventricular and Subtle Interventricular Differences in Cultured Unloaded Rat Cardiomyocytes. Front Physiol 2020; 11:815. [PMID: 32848817 PMCID: PMC7396550 DOI: 10.3389/fphys.2020.00815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/18/2020] [Indexed: 01/22/2023] Open
Abstract
The chambers of the heart fulfill different hemodynamic functions, which are reflected in their structural and contractile properties. While the atria are highly elastic to allow filling from the venous system, the ventricles need to be able to produce sufficiently high pressures to eject blood into the circulation. The right ventricle (RV) pumps into the low pressure pulmonary circulation, while the left ventricle (LV) needs to overcome the high pressure of the systemic circulation. It is incompletely understood whether these differences can be explained by the contractile differences at the level of the individual cardiomyocytes of the chambers. We addressed this by isolating cardiomyocytes from atria, RV, LV, and interventricular septum (IVS) of five healthy wild-type rats. Using a high-throughput contractility set-up, we measured contractile function of 2,043 cells after overnight culture. Compared to ventricular cardiomyocytes, atrial cells showed a twofold lower contraction amplitude and 1.4- to 1.7-fold slower kinetics of contraction and relaxation. The interventricular differences in contractile function were much smaller; RV cells displayed 12–13% less fractional shortening and 5–9% slower contraction and 3–15% slower relaxation kinetics relative to their LV and IVS counterparts. Aided by a large dataset, we established relationships between contractile parameters and found contraction velocity, fractional shortening and relaxation velocity to be highly correlated. In conclusion, our findings are in line with contractile differences observed at the atrioventricular level, but can only partly explain the interventricular differences that exist at the organ level.
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Affiliation(s)
- Edgar E Nollet
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | | | - Max Goebel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Valentijn Jansen
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Cord Brockmann
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Jorrit Osinga
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Michiel Helmes
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,CytoCypher BV, Wageningen, Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
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24
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Maria Z, Campolo AR, Scherlag BJ, Ritchey JW, Lacombe VA. Insulin Treatment Reduces Susceptibility to Atrial Fibrillation in Type 1 Diabetic Mice. Front Cardiovasc Med 2020; 7:134. [PMID: 32903422 PMCID: PMC7434932 DOI: 10.3389/fcvm.2020.00134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 06/30/2020] [Indexed: 12/19/2022] Open
Abstract
Diabetes has been identified as an independent risk factor for atrial fibrillation (AF), the most common chronic cardiac arrhythmia. Whether or not glucose and insulin disturbances observed during diabetes enhance arrhythmogenicity of the atria, potentially leading to AF, is not well-known. We hypothesized that insulin deficiency and impaired glucose transport provide a metabolic substrate for the development and maintenance of AF during diabetes. Transesophageal atrial pacing was used to induce AF in healthy, streptozotocin-induced insulin-deficient type 1 diabetic, and insulin-treated diabetic mice. Translocation of insulin-sensitive glucose transporters (GLUTs) to the atrial cell surface was measured using a biotinylated photolabeling assay in the perfused heart. Fibrosis and glycogen accumulation in the atrium were measured using histological analysis. Diabetic mice displayed mild hyperglycemia, increased duration and frequency of AF episodes vs. age-matched controls (e.g., AF duration: 19.7 ± 6.8 s vs. 1.8 ± 1.1 s, respectively, p = 0.032), whereas insulin-treated diabetic animals did not. The translocation of insulin-sensitive GLUT-4 and -8 to the atrial cell surface was significantly downregulated in the diabetic mice (by 67 and 79%, respectively; p ≤ 0.001), and rescued by insulin treatment. We did not observe fibrosis or glycogen accumulation in the atria of diabetic mice. Therefore, these data suggest that insulin and glucose disturbances were sufficient to induce AF susceptibility during mild diabetes.
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Affiliation(s)
- Zahra Maria
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, United States.,Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Allison R Campolo
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, United States.,Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Benjamin J Scherlag
- Department of Internal Medicine, University of Oklahoma College of Medicine, Oklahoma City, OK, United States
| | - Jerry W Ritchey
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, United States
| | - Véronique A Lacombe
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, United States.,Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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25
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Goette A, Patscheke M, Henschke F, Hammwöhner M. COVID-19-Induced Cytokine Release Syndrome Associated with Pulmonary Vein Thromboses, Atrial Cardiomyopathy, and Arterial Intima Inflammation. TH Open 2020; 4:e271-e279. [PMID: 32995705 PMCID: PMC7519876 DOI: 10.1055/s-0040-1716717] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/11/2020] [Indexed: 02/06/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19) is a viral disease induced by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), which may cause an acute respiratory distress syndrome (ARDS). First reports have shown that elevated levels of inflammatory cytokines might be involved in the development of organ dysfunction in COVID-19. Here, we can present a case of cytokine release syndrome induced by SARS-CoV-2 causing multiorgan failure and death. Of note, we can report on pulmonary vein thromboses as potential source of cerebrovascular embolic events. Furthermore, we present a specific form of an isolated inflammatory atrial cardiomyopathy encompassing atrial myocardium, perivascular matrix, as well as atrial autonomic nerve ganglia, causing atrial fibrillation, sinus node arrest, as well as atrial clot formation in the right atrial appendage. An associated acute glomerulonephritis caused acute kidney failure. Furthermore, all the described pathologies of organs and vessels were associated with increased local expression of interleukin-6 and monocyte chemoattractant protein-1 (MCP-1). This report provides new evidence about fatal pathologies and summarizes the current knowledge about organ manifestations observed in COVID-19.
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Affiliation(s)
- Andreas Goette
- Department of Cardiology and Intensive Care Medicine, St. Vincenz Hospital, Paderborn, Germany
- Working Group: Molecular Electrophysiology, University Hospital Magdeburg, Magdeburg, Germany
| | - Markus Patscheke
- Department of Cardiology and Intensive Care Medicine, St. Vincenz Hospital, Paderborn, Germany
| | | | - Matthias Hammwöhner
- Department of Cardiology and Intensive Care Medicine, St. Vincenz Hospital, Paderborn, Germany
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26
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Wang H, Varagic J, Nagata S, Kon ND, Ahmad S, VonCannon JL, Wright KN, Sun X, Deal D, Groban L, Ferrario CM. Atrial angiotensin-(1-12)/chymase expression data in patient of heart diseases. Data Brief 2020; 31:105744. [PMID: 32490094 PMCID: PMC7256457 DOI: 10.1016/j.dib.2020.105744] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/15/2020] [Indexed: 12/15/2022] Open
Abstract
The data presented here are related to the research article entitled “Differential expression of the angiotensin-(1-12) [Ang-(1-12)]/chymase axis in human atrial tissue [1]. We have showed that chymase gene transcripts, chymase activity, and immunoreactive- Ang-(1-12) expression levels were higher in left compared to right atrial tissue, irrespective of cardiac disease. This article presents the echocardiographic characteristics of 111 patients undergoing heart surgery for the correction of valvular heart disease, resistant atrial fibrillation or ischemic heart disease. Left atrial chymase mRNA expression and activity, and left atrial Ang-(1-12) levels were compared between patients with stroke vs. non-stroke, congestive heart failure vs. non-heart failure, and in cardiac surgery patients who had a history of postoperative atrial fibrillation vs. non-atrial fibrillation.
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Affiliation(s)
- Hao Wang
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Internal Medicine-Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Jasmina Varagic
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Hypertension and Vascular Research Center, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Sayaka Nagata
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Neal D Kon
- Department of Cardiothoracic Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Sarfaraz Ahmad
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Jessica L VonCannon
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Kendra N Wright
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Xuming Sun
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Dwight Deal
- Department of Cardiothoracic Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Leanne Groban
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Internal Medicine-Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Carlos M Ferrario
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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27
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Martinez-Mateu L, Saiz J, Aromolaran AS. Differential Modulation of IK and ICa,L Channels in High-Fat Diet-Induced Obese Guinea Pig Atria. Front Physiol 2019; 10:1212. [PMID: 31607952 PMCID: PMC6773813 DOI: 10.3389/fphys.2019.01212] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/05/2019] [Indexed: 12/31/2022] Open
Abstract
Obesity mechanisms that make atrial tissue vulnerable to arrhythmia are poorly understood. Voltage-dependent potassium (IK, IKur, and IK1) and L-type calcium currents (ICa,L) are electrically relevant and represent key substrates for modulation in obesity. We investigated whether electrical remodeling produced by high-fat diet (HFD) alone or in concert with acute atrial stimulation were different. Electrophysiology was used to assess atrial electrical function after short-term HFD-feeding in guinea pigs. HFD atria displayed spontaneous beats, increased IK (IKr + IKs) and decreased ICa,L densities. Only with pacing did a reduction in IKur and increased IK1 phenotype emerge, leading to a further shortening of action potential duration. Computer modeling studies further indicate that the measured changes in potassium and calcium current densities contribute prominently to shortened atrial action potential duration in human heart. Our data are the first to show that multiple mechanisms (shortened action potential duration, early afterdepolarizations and increased incidence of spontaneous beats) may underlie initiation of supraventricular arrhythmias in obese guinea pig hearts. These results offer different mechanistic insights with implications for obese patients harboring supraventricular arrhythmias.
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Affiliation(s)
- Laura Martinez-Mateu
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Ademuyiwa S Aromolaran
- Cardiac Electrophysiology and Metabolism Research Group, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, United States
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28
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Bayer JD, Boukens BJ, Krul SPJ, Roney CH, Driessen AHG, Berger WR, van den Berg NWE, Verkerk AO, Vigmond EJ, Coronel R, de Groot JR. Acetylcholine Delays Atrial Activation to Facilitate Atrial Fibrillation. Front Physiol 2019; 10:1105. [PMID: 31551802 PMCID: PMC6737394 DOI: 10.3389/fphys.2019.01105] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 08/09/2019] [Indexed: 11/13/2022] Open
Abstract
Background Acetylcholine (ACh) shortens action potential duration (APD) in human atria. APD shortening facilitates atrial fibrillation (AF) by reducing the wavelength for reentry. However, the influence of ACh on electrical conduction in human atria and its contribution to AF are unclear, particularly when combined with impaired conduction from interstitial fibrosis. Objective To investigate the effect of ACh on human atrial conduction and its role in AF with computational, experimental, and clinical approaches. Methods S1S2 pacing (S1 = 600 ms and S2 = variable cycle lengths) was applied to the following human AF computer models: a left atrial appendage (LAA) myocyte to quantify the effects of ACh on APD, maximum upstroke velocity (V max ), and resting membrane potential (RMP); a monolayer of LAA myocytes to quantify the effects of ACh on conduction; and 3) an intact left atrium (LA) to determine the effects of ACh on arrhythmogenicity. Heterogeneous ACh and interstitial fibrosis were applied to the monolayer and LA models. To corroborate the simulations, APD and RMP from isolated human atrial myocytes were recorded before and after 0.1 μM ACh. At the tissue level, LAAs from AF patients were optically mapped ex vivo using Di-4-ANEPPS. The difference in total activation time (AT) was determined between AT initially recorded with S1 pacing, and AT recorded during subsequent S1 pacing without (n = 6) or with (n = 7) 100 μM ACh. Results In LAA myocyte simulations, S1 pacing with 0.1 μM ACh shortened APD by 41 ms, hyperpolarized RMP by 7 mV, and increased V max by 27 mV/ms. In human atrial myocytes, 0.1 μM ACh shortened APD by 48 ms, hyperpolarized RMP by 3 mV, and increased V max by 6 mV/ms. In LAA monolayer simulations, S1 pacing with ACh hyperpolarized RMP to delay total AT by 32 ms without and 35 ms with fibrosis. This led to unidirectional conduction block and sustained reentry in fibrotic LA with heterogeneous ACh during S2 pacing. In AF patient LAAs, S1 pacing with ACh increased total AT from 39.3 ± 26 ms to 71.4 ± 31.2 ms (p = 0.036) compared to no change without ACh (56.7 ± 29.3 ms to 50.0 ± 21.9 ms, p = 0.140). Conclusion In fibrotic atria with heterogeneous parasympathetic activation, ACh facilitates AF by shortening APD and slowing conduction to promote unidirectional conduction block and reentry.
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Affiliation(s)
- Jason D Bayer
- Electrophysiology and Heart Modeling Institute (IHU-LIRYC), Bordeaux University Foundation, Bordeaux, France.,Institute of Mathematics of Bordeaux (U5251), University of Bordeaux, Bordeaux, France
| | - Bastiaan J Boukens
- Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Sébastien P J Krul
- Department of Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | - Caroline H Roney
- Division of Imaging Sciences and Bioengineering, King's College London, London, United Kingdom
| | | | - Wouter R Berger
- Department of Cardiology, Academic Medical Center, Amsterdam, Netherlands.,Department of Cardiology, Heart Center, OLVG, Amsterdam, Netherlands
| | | | - Arie O Verkerk
- Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands.,Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | - Edward J Vigmond
- Electrophysiology and Heart Modeling Institute (IHU-LIRYC), Bordeaux University Foundation, Bordeaux, France.,Institute of Mathematics of Bordeaux (U5251), University of Bordeaux, Bordeaux, France
| | - Ruben Coronel
- Electrophysiology and Heart Modeling Institute (IHU-LIRYC), Bordeaux University Foundation, Bordeaux, France.,Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | - Joris R de Groot
- Department of Cardiology, Academic Medical Center, Amsterdam, Netherlands
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29
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Bayat F, Baghaei R, Safi M, Aval ZA, Khaheshi I, Naderian M. Huge aneurysmal fistula from left main artery to right atrium in a man with atypical chest pain and dyspnea on exertion. Future Cardiol 2019; 15:85-88. [PMID: 30848672 DOI: 10.2217/fca-2018-0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We present a 33-year-old man with atypical chest pain and with no significant past medical history. The patient was finally diagnosed as a case of huge fistula from the left main coronary artery to the right atrium, a very rare condition with challenging diagnostic and therapeutic approaches. The majority of cases of coronary artery fistula are small, asymptomatic and clinically undetectable; they frequently do not cause any complications and can spontaneously resolve. However, larger fistulas are frequently three times the size of a typical caliber of a coronary artery and may or may not cause symptoms or complications.
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Affiliation(s)
- Fariba Bayat
- Cardiovascular Research Center, Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ramin Baghaei
- Cardiac Surgery Department, Modarres Hospital, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Morteza Safi
- Cardiovascular Research Center, Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Ansari Aval
- Cardiac Surgery Department, Modarres Hospital, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Isa Khaheshi
- Cardiovascular Research Center, Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Naderian
- Non-Communicable Diseases Research Center, Endocrinology & Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.,Cardiovascular Research Department, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
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30
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Jainandunsing JS, Linnemann R, Bouma W, Natour N, Bidar E, Lorusso R, Gelsomino S, Johnson DM, Natour E. Aorto- atrial fistula formation and closure: a systematic review. J Thorac Dis 2019; 11:1031-1046. [PMID: 31019793 DOI: 10.21037/jtd.2019.01.77] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Blood flow between the aorta and atrium is a rare but complex pathological condition, also known as aorto-atrial fistula (AAF). The exact incidence of this condition is unknown, as are the major precipitating factors and best treatment options. We carried out a systematic review of the available case report literature reporting AAF. We systematically reviewed literature on AAF formation and closure. Separate Medline (PubMed), EMBASE, and Cochrane database queries were performed. The following MESH headings were used: atrium, ventricle, fistula, cardiac, shunts, aortic, aorto-atrial tunnels and coronary cameral fistula. All papers were considered for analysis irrespective of their quality, or the journal in which they were published. Fistula formation from the ascending aorta to the atria occurred more often in the right atrium compared to the left. Endocarditis was the major cause of AAF formation, whilst congenital causes were responsible for nearly 12%. In a number of cases fistula formation occurred secondary to cardiac surgery, whilst chest traumas were a relatively rare cause of AAF. Correction via an open surgical approach occurred in 73.5% of cases, whilst percutaneous intervention was utilised in 10% of patients. In 74.3% of all studied cases the fistula repair was successful and patients survived the procedures. In 14.7% of the cases patients did not survive. Similar outcomes were observed between percutaneous and surgical interventions. Data from larger populations with AAF is lacking, meaning that specific data regarding incidence and prevalence does currently not exist.
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Affiliation(s)
- Jayant S Jainandunsing
- University of Groningen, University Medical Center Groningen, Department of Anesthesiology, The Netherlands
| | - Ralph Linnemann
- University of Groningen, University Medical Center Groningen, Department of Cardiothoracic Surgery, The Netherlands
| | - Wobbe Bouma
- University of Groningen, University Medical Center Groningen, Department of Cardiothoracic Surgery, The Netherlands
| | - Nicole Natour
- University of Maastricht, Department of Radiology, Universiteitssingel 50, ER Maastricht 6229, The Netherlands
| | - Elham Bidar
- University of Maastricht, Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht - CARIM, Universiteitssingel 50, ER Maastricht 6229, The Netherlands
| | - Roberto Lorusso
- University of Maastricht, Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht - CARIM, Universiteitssingel 50, ER Maastricht 6229, The Netherlands
| | - Sandro Gelsomino
- University of Maastricht, Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht - CARIM, Universiteitssingel 50, ER Maastricht 6229, The Netherlands
| | - Daniel M Johnson
- University of Maastricht, Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht - CARIM, Universiteitssingel 50, ER Maastricht 6229, The Netherlands
| | - Ehsan Natour
- University of Groningen, University Medical Center Groningen, Department of Cardiothoracic Surgery, The Netherlands
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31
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kanaporis G, Kalik ZM, Blatter LA. Action potential shortening rescues atrial calcium alternans. J Physiol 2018; 597:723-740. [PMID: 30412286 DOI: 10.1113/jp277188] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/08/2018] [Indexed: 01/08/2023] Open
Abstract
KEY POINTS Cardiac alternans refers to a beat-to-beat alternation in contraction, action potential (AP) morphology and Ca2+ transient (CaT) amplitude, and represents a risk factor for cardiac arrhythmia, including atrial fibrillation. We developed strategies to pharmacologically manipulate the AP waveform with the goal to reduce or eliminate the occurrence of CaT and contraction alternans in atrial tissue. With combined patch-clamp and intracellular Ca2+ measurements we investigated the effect of specific ion channel inhibitors and activators on alternans. In single rabbit atrial myocytes, suppression of Ca2+ -activated Cl- channels eliminated AP duration alternans, but prolonged the AP and failed to eliminate CaT alternans. In contrast, activation of K+ currents (IKs and IKr ) shortened the AP and eliminated both AP duration and CaT alternans. As demonstrated also at the whole heart level, activation of K+ conductances represents a promising strategy to suppress alternans, and thus reducing a risk factor for atrial fibrillation. ABSTRACT At the cellular level alternans is observed as beat-to-beat alternations in contraction, action potential (AP) morphology and magnitude of the Ca2+ transient (CaT). Alternans is a well-established risk factor for cardiac arrhythmia, including atrial fibrillation. This study investigates whether pharmacological manipulation of AP morphology is a viable strategy to reduce the risk of arrhythmogenic CaT alternans. Pacing-induced AP and CaT alternans were studied in rabbit atrial myocytes using combined Ca2+ imaging and electrophysiological measurements. Increased AP duration (APD) and beat-to-beat alternations in AP morphology lowered the pacing frequency threshold and increased the degree of CaT alternans. Inhibition of Ca2+ -activated Cl- channels reduced beat-to-beat AP alternations, but prolonged APD and failed to suppress CaT alternans. In contrast, AP shortening induced by activators of two K+ channels (ML277 for Kv7.1 and NS1643 for Kv11.1) abolished both APD and CaT alternans in field-stimulated and current-clamped myocytes. K+ channel activators had no effect on the degree of Ca2+ alternans in AP voltage-clamped cells, confirming that suppression of Ca2+ alternans was caused by the changes in AP morphology. Finally, activation of Kv11.1 channel significantly attenuated or even abolished atrial T-wave alternans in isolated Langendorff perfused hearts. In summary, AP shortening suppressed or completely eliminated both CaT and APD alternans in single atrial myocytes and atrial T-wave alternans at the whole heart level. Therefore, we suggest that AP shortening is a potential intervention to avert development of alternans with important ramifications for arrhythmia prevention and therapy.
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Affiliation(s)
- Giedrius Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, IL, 60612, USA
| | - Zane M Kalik
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, IL, 60612, USA
| | - Lothar A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, IL, 60612, USA
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Krumm P, Krauß S, Mangold S, Zitzelsberger T, Klumpp BD, Nikolaou K, Nieß AM, Kramer U, Burgstahler C. Mid-term development of the right ventricle in competitive athletes. Acta Radiol 2018; 59:1422-1430. [PMID: 29566549 DOI: 10.1177/0284185118764203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Long-term intensive training induces physiological, morphological, and functional adaption of the athlete's heart. PURPOSE To evaluate the development of athlete's heart during a mid-term follow-up of competitive athletes using cardiac magnetic resonance (CMR). MATERIAL AND METHODS Eighteen competitive long-distance runners and triathletes (age 43 ± 13 years, 3 women) were prospectively examined in a longitudinal follow-up study 5.05 ± 0.6 years after baseline. CMR at 1.5-T was performed for functional and late gadolinium enhancement (LGE) imaging. Left ventricular (LV) and right ventricular (RV) end-diastolic volume (LVEDV, RVEDV) as well as ejection fraction (LVEF, RVEF), LV myocardial mass (LVMM), and atrial sizes were determined and compared to baseline in matched pairs statistics for paired difference. RESULTS LVEDV (197 ± 38 mL vs. 196 ± 38 mL, paired difference -0.9 mL, P = 0.7) and LVEF (62 ± 7% vs. 62 ± 5%, paired difference 0.1%, P = 0.9) did not change during the follow-up period, whereas LVMM increased significantly (149 ± 31 g vs.164 ± 32 g, paired difference 14 g, P < 0.0001). RVEDV significantly increased from 221 ± 47 mL at baseline to 230 ± 52 mL (paired difference 10 mL, P = 0.0033). RVEF decreased from baseline 57 ± 8% to 53 ± 7% (paired difference -3%, P = 0.0234). Left atrial size showed no significant changes (24 ± 5 cm2 vs. 25 ± 6 cm2, paired difference 0.5 cm2, P = 0.17) and right atrial size increased significantly (30 ± 5 cm2 vs. 32 ± 4 cm2, paired difference 2 cm2, P = 0.0054). CONCLUSION This study supports the theory of ongoing remodeling in an athlete's heart. Predominantly the right heart can further enlarge in a mid-term period. This response seems not linearly dependent on a steady, decreased, or increased training volume.
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Affiliation(s)
- Patrick Krumm
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Stefan Krauß
- Department of Internal Medicine V, Sports Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Stefanie Mangold
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Tanja Zitzelsberger
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Bernhard D Klumpp
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Department of Radiology, Rems-Murr-Clinic, Winnenden, Germany
| | - Konstantin Nikolaou
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Andreas M Nieß
- Department of Internal Medicine V, Sports Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Ulrich Kramer
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Department of Radiology, Rems-Murr-Clinic, Winnenden, Germany
| | - Christof Burgstahler
- Department of Internal Medicine V, Sports Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
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Brandenburg S, Pawlowitz J, Fakuade FE, Kownatzki-Danger D, Kohl T, Mitronova GY, Scardigli M, Neef J, Schmidt C, Wiedmann F, Pavone FS, Sacconi L, Kutschka I, Sossalla S, Moser T, Voigt N, Lehnart SE. Axial Tubule Junctions Activate Atrial Ca 2+ Release Across Species. Front Physiol 2018; 9:1227. [PMID: 30349482 PMCID: PMC6187065 DOI: 10.3389/fphys.2018.01227] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/14/2018] [Indexed: 01/10/2023] Open
Abstract
Rationale: Recently, abundant axial tubule (AT) membrane structures were identified deep inside atrial myocytes (AMs). Upon excitation, ATs rapidly activate intracellular Ca2+ release and sarcomeric contraction through extensive AT junctions, a cell-specific atrial mechanism. While AT junctions with the sarcoplasmic reticulum contain unusually large clusters of ryanodine receptor 2 (RyR2) Ca2+ release channels in mouse AMs, it remains unclear if similar protein networks and membrane structures exist across species, particularly those relevant for atrial disease modeling. Objective: To examine and quantitatively analyze the architecture of AT membrane structures and associated Ca2+ signaling proteins across species from mouse to human. Methods and Results: We developed superresolution microscopy (nanoscopy) strategies for intact live AMs based on a new custom-made photostable cholesterol dye and immunofluorescence imaging of membraneous structures and membrane proteins in fixed tissue sections from human, porcine, and rodent atria. Consistently, in mouse, rat, and rabbit AMs, intact cell-wide tubule networks continuous with the surface membrane were observed, mainly composed of ATs. Moreover, co-immunofluorescence nanoscopy showed L-type Ca2+ channel clusters adjacent to extensive junctional RyR2 clusters at ATs. However, only junctional RyR2 clusters were highly phosphorylated and may thus prime Ca2+ release at ATs, locally for rapid signal amplification. While the density of the integrated L-type Ca2+ current was similar in human and mouse AMs, the intracellular Ca2+ transient showed quantitative differences. Importantly, local intracellular Ca2+ release from AT junctions occurred through instantaneous action potential propagation via transverse tubules (TTs) from the surface membrane. Hence, sparse TTs were sufficient as electrical conduits for rapid activation of Ca2+ release through ATs. Nanoscopy of atrial tissue sections confirmed abundant ATs as the major network component of AMs, particularly in human atrial tissue sections. Conclusion: AT junctions represent a conserved, cell-specific membrane structure for rapid excitation-contraction coupling throughout a representative spectrum of species including human. Since ATs provide the major excitable membrane network component in AMs, a new model of atrial “super-hub” Ca2+ signaling may apply across biomedically relevant species, opening avenues for future investigations about atrial disease mechanisms and therapeutic targeting.
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Affiliation(s)
- Sören Brandenburg
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Jan Pawlowitz
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Funsho E Fakuade
- Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Daniel Kownatzki-Danger
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Kohl
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Gyuzel Y Mitronova
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Marina Scardigli
- European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy
| | - Jakob Neef
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Constanze Schmidt
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany.,Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Felix Wiedmann
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany.,Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Francesco S Pavone
- European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy.,Department of Physics, University of Florence, Florence, Italy
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy
| | - Ingo Kutschka
- Department of Cardiothoracic and Vascular Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Samuel Sossalla
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Niels Voigt
- Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Göttingen, Göttingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Göttingen, Göttingen, Germany.,BioMET, The Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
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35
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Roshchevskaya IM, Smirnova SL, Tsorin IB, Stolyaruk VN, Nadorova AV, Vititnova MB, Kolik LG, Kryzhanovskii SA. Specific Features of Depolarization of the Left and Right Atria in Rats with Alcoholic Cardiomyopathy. Bull Exp Biol Med 2018; 165:617-620. [PMID: 30225698 DOI: 10.1007/s10517-018-4226-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Indexed: 11/27/2022]
Abstract
Using a translation model of alcoholic cardiomyopathy in rats we showed the presence of an additional abnormal excitation focus in the area of the pulmonary vein lacunae in the left atrium and enhanced heterogeneity of the atrium depolarization pattern. These changes can determine electric instability of the myocardium and induce malignant heart rhythm disturbances including, sudden cardiac death.
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Affiliation(s)
- I M Roshchevskaya
- Department of Comparative Cardiology, Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Komi Republic, Russia
| | - S L Smirnova
- Department of Comparative Cardiology, Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Komi Republic, Russia
| | - I B Tsorin
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - V N Stolyaruk
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - A V Nadorova
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - M B Vititnova
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - L G Kolik
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
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36
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Tan R, Ahn YM, Kim HY, Lee YJ, Cho KW, Kang DG, Lee HS. Atrial secretion of ANP is suppressed in renovascular hypertension: shifting of ANP secretion from atria to the left ventricle. Am J Physiol Heart Circ Physiol 2018; 315:H590-H601. [PMID: 29979625 DOI: 10.1152/ajpheart.00612.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, the change in secretion of atrial natriuretic peptide (ANP) from the atria was defined in hypertension accompanied by ventricular hypertrophy and increased synthesis of ANP. To identify the change of the secretion and mechanisms involved, experiments were performed in isolated perfused beating atria from sham-operated normotensive and renovascular hypertensive rats. Expression of ANP, natriuretic peptide receptor (NPR)-C, components of the renin-angiotensin system, and muscarinic signaling pathway was measured in cardiac tissues. Basal levels of ANP secretion and acetylcholine (ACh)- and stretch-induced activation of ANP secretion were suppressed in the atria from hypertensive compared with normotensive rats. ACh increased ANP secretion via M2 muscarinic ACh receptor-ACh-sensitive K+ channel signaling. In hypertensive rats, ANP concentration increased in the left ventricle but decreased in the right ventricle. The atrial concentration of ANP was not changed in hypertensive compared with normotensive rats. ANP mRNA expression was accentuated in the left ventricle but suppressed in the other cardiac chambers in the hearts of hypertensive rats. NPR-C expression was inversely related to ANP mRNA levels. Angiotensin II type 1 receptor (AT1R) expression was accentuated in the cardiac chambers from hypertensive rats compared with normotensive rats, whereas angiotensin II type 2 receptor, M2 muscarinic receptor, and Kir3.4 channels were suppressed. AT1R blockade with losartan reversed the change observed in hypertensive rats. The present findings indicate that renovascular hypertension shifts the major site of ANP secretion and synthesis from the atria to the left ventricle through modulation of the expression of ANP, NPR-C, AT1R, and the M2 muscarinic signaling pathway. NEW & NOTEWORTHY Renovascular hypertension suppresses the atrial secretion of ANP and shifts the major site of the regulation of ANP secretion and synthesis from atria to the hypertrophied left ventricle possibly via modulation of the expression of ANP, natriuretic peptide receptor-C, angiotensin II subtype 1 receptor, and M2 muscarinic signaling pathway.
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Affiliation(s)
- Rui Tan
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
| | - You Mee Ahn
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
| | - Hye Yoom Kim
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
| | - Yun Jung Lee
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
| | - Kyung Woo Cho
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
| | - Dae Gill Kang
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
| | - Ho Sub Lee
- Hanbang Cardio-Renal Syndrome Research Center, Department of Herbal Resources, Professional Graduate School of Oriental Medicine Wonkwang University, Iksan, Korea
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Carstensen H, Hesselkilde EZ, Fenner M, Loft-Andersen AV, Flethøj M, Kanters JK, Sattler SM, Tfelt-Hansen J, Pehrson S, Jespersen T, Buhl R. Time-dependent antiarrhythmic effects of flecainide on induced atrial fibrillation in horses. J Vet Intern Med 2018; 32:1708-1717. [PMID: 30133839 PMCID: PMC6189357 DOI: 10.1111/jvim.15287] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/31/2018] [Accepted: 06/26/2018] [Indexed: 11/28/2022] Open
Abstract
Background Pharmacological treatment of atrial fibrillation (AF) in horses can be challenging because of low efficacy and adverse effects. Flecainide has been tested with variable efficacy. Objective To test whether the efficacy of flecainide is dependent on AF duration. Animals Nine Standardbred mares. Methods Factorial study design. All horses were instrumented with a pacemaker and assigned to a control or an AF group. On day 0, all horses were in sinus rhythm and received 2 mg/kg flecainide IV. Atrial fibrillation subsequently was induced in the AF group by pacemaker stimulation. On days 3, 9, 27, and 55, flecainide was administered to all horses, regardless of heart rhythm. Results All horses in AF cardioverted to sinus rhythm on days 3 and 9. On day 27, 5/6 horses cardioverted, whereas only 2/6 cardioverted on day 55. The time from the start of flecainide infusion to cardioversion (range, 3–185 min, log transformed) showed linear correlation with the cumulative duration of AF (r2 = .80, P < .0001). Flecainide induced abnormal QRS complexes in 4/6 AF horses and 1/3 controls. A positive correlation was found between heart rate before flecainide infusion and number of abnormal QRS complexes (0.14, P < .05). One horse suffered from cardiac arrest and died after flecainide infusion. Conclusions and Clinical Importance Flecainide is effective for cardioversion of short‐term induced AF, but the effect decreases with AF duration. Controlling heart rate may minimize adverse effects caused by flecainide, but the drug should be used with great caution.
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Affiliation(s)
- Helena Carstensen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Eva Z Hesselkilde
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Merle Fenner
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Ameli V Loft-Andersen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Mette Flethøj
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Jørgen K Kanters
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark
| | - Stefan M Sattler
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, København, Denmark.,Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany
| | - Jacob Tfelt-Hansen
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, København, Denmark.,Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark
| | - Steen Pehrson
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, København, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark
| | - Rikke Buhl
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
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Laing J, Moore J, Vassallo R, Bainbridge D, Drangova M, Peters T. Patient-specific cardiac phantom for clinical training and preprocedure surgical planning. J Med Imaging (Bellingham) 2018; 5:021222. [PMID: 29594183 DOI: 10.1117/1.jmi.5.2.021222] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/05/2018] [Indexed: 11/14/2022] Open
Abstract
Minimally invasive mitral valve repair procedures including MitraClip® are becoming increasingly common. For cases of complex or diseased anatomy, clinicians may benefit from using a patient-specific cardiac phantom for training, surgical planning, and the validation of devices or techniques. An imaging compatible cardiac phantom was developed to simulate a MitraClip® procedure. The phantom contained a patient-specific cardiac model manufactured using tissue mimicking materials. To evaluate accuracy, the patient-specific model was imaged using computed tomography (CT), segmented, and the resulting point cloud dataset was compared using absolute distance to the original patient data. The result, when comparing the molded model point cloud to the original dataset, resulted in a maximum Euclidean distance error of 7.7 mm, an average error of 0.98 mm, and a standard deviation of 0.91 mm. The phantom was validated using a MitraClip® device to ensure anatomical features and tools are identifiable under image guidance. Patient-specific cardiac phantoms may allow for surgical complications to be accounted for preoperative planning. The information gained by clinicians involved in planning and performing the procedure should lead to shorter procedural times and better outcomes for patients.
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Affiliation(s)
- Justin Laing
- Western University, Department of Biomedical Engineering, London, Ontario, Canada
| | - John Moore
- Robarts Research Institute, London, Ontario, Canada
| | - Reid Vassallo
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Daniel Bainbridge
- Western University, Department of Anesthesiology, London, Ontario, Canada
| | - Maria Drangova
- Western University, Department of Biomedical Engineering, London, Ontario, Canada.,Robarts Research Institute, London, Ontario, Canada.,Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Terry Peters
- Western University, Department of Biomedical Engineering, London, Ontario, Canada.,Robarts Research Institute, London, Ontario, Canada.,Western University, Department of Medical Biophysics, London, Ontario, Canada
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39
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Ashton JL, Burton RAB, Bub G, Smaill BH, Montgomery JM. Synaptic Plasticity in Cardiac Innervation and Its Potential Role in Atrial Fibrillation. Front Physiol 2018; 9:240. [PMID: 29615932 PMCID: PMC5869186 DOI: 10.3389/fphys.2018.00240] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/06/2018] [Indexed: 12/30/2022] Open
Abstract
Synaptic plasticity is defined as the ability of synapses to change their strength of transmission. Plasticity of synaptic connections in the brain is a major focus of neuroscience research, as it is the primary mechanism underpinning learning and memory. Beyond the brain however, plasticity in peripheral neurons is less well understood, particularly in the neurons innervating the heart. The atria receive rich innervation from the autonomic branch of the peripheral nervous system. Sympathetic neurons are clustered in stellate and cervical ganglia alongside the spinal cord and extend fibers to the heart directly innervating the myocardium. These neurons are major drivers of hyperactive sympathetic activity observed in heart disease, ventricular arrhythmias, and sudden cardiac death. Both pre- and postsynaptic changes have been observed to occur at synapses formed by sympathetic ganglion neurons, suggesting that plasticity at sympathetic neuro-cardiac synapses is a major contributor to arrhythmias. Less is known about the plasticity in parasympathetic neurons located in clusters on the heart surface. These neuronal clusters, termed ganglionated plexi, or “little brains,” can independently modulate neural control of the heart and stimulation that enhances their excitability can induce arrhythmia such as atrial fibrillation. The ability of these neurons to alter parasympathetic activity suggests that plasticity may indeed occur at the synapses formed on and by ganglionated plexi neurons. Such changes may not only fine-tune autonomic innervation of the heart, but could also be a source of maladaptive plasticity during atrial fibrillation.
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Affiliation(s)
- Jesse L Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Gil Bub
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Bruce H Smaill
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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Nobles M, Montaigne D, Sebastian S, Birnbaumer L, Tinker A. Differential effects of inhibitory G protein isoforms on G protein-gated inwardly rectifying K + currents in adult murine atria. Am J Physiol Cell Physiol 2018; 314:C616-C626. [PMID: 29342363 DOI: 10.1152/ajpcell.00271.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
G protein-gated inwardly rectifying K+ (GIRK) channels are the major inwardly rectifying K+ currents in cardiac atrial myocytes and an important determinant of atrial electrophysiology. Inhibitory G protein α-subunits can both mediate activation via acetylcholine but can also suppress basal currents in the absence of agonist. We studied this phenomenon using whole cell patch clamping in murine atria from mice with global genetic deletion of Gαi2, combined deletion of Gαi1/Gαi3, and littermate controls. We found that mice with deletion of Gαi2 had increased basal and agonist-activated currents, particularly in the right atria while in contrast those with Gαi1/Gαi3 deletion had reduced currents. Mice with global genetic deletion of Gαi2 had decreased action potential duration. Tissue preparations of the left atria studied with a multielectrode array from Gαi2 knockout mice showed a shorter effective refractory period, with no change in conduction velocity, than littermate controls. Transcriptional studies revealed increased expression of GIRK channel subunit genes in Gαi2 knockout mice. Thus different G protein isoforms have differential effects on GIRK channel behavior and paradoxically Gαi2 act to increase basal and agonist-activated GIRK currents. Deletion of Gαi2 is potentially proarrhythmic in the atria.
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Affiliation(s)
- Muriel Nobles
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry , London , United Kingdom
| | - David Montaigne
- Centre Hospitalier Régional Universitaire de Lille , Lille , France.,Université Lille 2 , Lille , France.,Institut National de la Santé et de la Recherche Médicale, U1011, Lille , France.,European Genomic Institute for Diabetes , Lille , France.,Institut Pasteur de Lille , Lille , France
| | - Sonia Sebastian
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry , London , United Kingdom
| | - Lutz Birnbaumer
- Division of Intramural Research, National Institute of Environmental Health Sciences , Research Triangle Park, North Carolina.,Institute of Biomedical Research, Catholic University of Argentina , Buenos Aires , Argentina
| | - Andrew Tinker
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry , London , United Kingdom
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Vysotskaya Z, Chidipi B, Rodgers JL, Tang X, Samal E, Kolliputi N, Mohapatra S, Bennett ES, Panguluri SK. Elevated potassium outward currents in hyperoxia treated atrial cardiomyocytes. J Cell Physiol 2017; 233:4317-4326. [PMID: 29139549 DOI: 10.1002/jcp.26263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/09/2017] [Indexed: 12/18/2022]
Abstract
Supplementation of 100% oxygen is a very common intervention in intensive care units (ICU) and critical care centers for patients with dysfunctional lung and lung disorders. Although there is advantage in delivering sufficient levels of oxygen, hyperoxia is reported to be directly associated with increasing in-hospital deaths. Our previous studies reported ventricular and electrical remodeling in hyperoxia treated mouse hearts, and in this article, for the first time, we are investigating the effects of hyperoxia on atrial electrophysiology using whole-cell patch-clamp electrophysiology experiments along with assessment of Kv1.5, Kv4.2, and KChIP2 transcripts and protein profiles using real-time quantitative RT-PCR and Western blotting. Our data showed that induction of hyperoxia for 3 days in mice showed larger outward potassium currents with shorter action potential durations (APD). This increase in current densities is due to significant increase in ultrarapid delayed rectifier outward K+ currents (IKur ) and rapidly activating, rapidly inactivating transient outward K+ current (Ito ) densities. We also observed a significant increase in both transcripts and protein levels of Kv1.5 and KChIP2 in hyperoxia treated atrial cardiomyocytes, whereas no significant change was observed in Kv4.2 transcripts or protein. The data presented here further support our previous findings that hyperoxia induces not only ventricular remodeling, but also atrial electrical remodeling.
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Affiliation(s)
- Zhanna Vysotskaya
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Bojjibabu Chidipi
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jennifer L Rodgers
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, Florida
| | - Xiaolan Tang
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Eva Samal
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Narasaiah Kolliputi
- Division of Allergy and Immunology, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Subhra Mohapatra
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, Florida
| | - Eric S Bennett
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Siva K Panguluri
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, Florida
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Valli H, Ahmad S, Fraser JA, Jeevaratnam K, Huang CLH. Pro-arrhythmic atrial phenotypes in incrementally paced murine Pgc1β -/- hearts: effects of age. Exp Physiol 2017; 102:1619-1634. [PMID: 28960529 PMCID: PMC5725712 DOI: 10.1113/ep086589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/26/2017] [Indexed: 12/13/2022]
Abstract
New Findings What is the central question of this study? Can we experimentally replicate atrial pro‐arrhythmic phenotypes associated with important chronic clinical conditions, including physical inactivity, obesity, diabetes mellitus and metabolic syndrome, compromising mitochondrial function, and clarify their electrophysiological basis? What is the main finding and its importance? Electrocardiographic and intracellular cardiomyocyte recording at progressively incremented pacing rates demonstrated age‐dependent atrial arrhythmic phenotypes in Langendorff‐perfused murine Pgc1β−/− hearts for the first time. We attributed these to compromised action potential conduction and excitation wavefronts, whilst excluding alterations in recovery properties or temporal electrophysiological instabilities, clarifying these pro‐arrhythmic changes in chronic metabolic disease.
Atrial arrhythmias, most commonly manifesting as atrial fibrillation, represent a major clinical problem. The incidence of atrial fibrillation increases with both age and conditions associated with energetic dysfunction. Atrial arrhythmic phenotypes were compared in young (12–16 week) and aged (>52 week) wild‐type (WT) and peroxisome proliferative activated receptor, gamma, coactivator 1 beta (Ppargc1b)‐deficient (Pgc1β−/−) Langendorff‐perfused hearts, previously used to model mitochondrial energetic disorder. Electrophysiological explorations were performed using simultaneous whole‐heart ECG and intracellular atrial action potential (AP) recordings. Two stimulation protocols were used: an S1S2 protocol, which imposed extrasystolic stimuli at successively decremented intervals following regular pulse trains; and a regular pacing protocol at successively incremented frequencies. Aged Pgc1β−/− hearts showed greater atrial arrhythmogenicity, presenting as atrial tachycardia and ectopic activity. Maximal rates of AP depolarization (dV/dtmax) were reduced in Pgc1β−/− hearts. Action potential latencies were increased by the Pgc1β−/− genotype, with an added interactive effect of age. In contrast, AP durations to 90% recovery (APD90) were shorter in Pgc1β−/− hearts despite similar atrial effective recovery periods amongst the different groups. These findings accompanied paradoxical decreases in the incidence and duration of alternans in the aged and Pgc1β−/− hearts. Limiting slopes of restitution curves of APD90 against diastolic interval were correspondingly reduced interactively by Pgc1β−/− genotype and age. In contrast, reduced AP wavelengths were associated with Pgc1β−/− genotype, both independently and interacting with age, through the basic cycle lengths explored, with the aged Pgc1β−/− hearts showing the shortest wavelengths. These findings thus implicate AP wavelength in possible mechanisms for the atrial arrhythmic changes reported here.
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Affiliation(s)
- Haseeb Valli
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Shiraz Ahmad
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - James A Fraser
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Kamalan Jeevaratnam
- Physiological Laboratory, University of Cambridge, Cambridge, UK.,PU-RCSI School of Medicine, Perdana University, Serdang, Selangor Darul Ehsan, Malaysia.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Cambridge, UK.,Department of Biochemistry, University of Cambridge, Cambridge, UK
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Clarke JD, Caldwell JL, Pearman CM, Eisner DA, Trafford AW, Dibb KM. Increased Ca buffering underpins remodelling of Ca 2+ handling in old sheep atrial myocytes. J Physiol 2017; 595:6263-6279. [PMID: 28752958 PMCID: PMC5621500 DOI: 10.1113/jp274053] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 07/26/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Ageing is associated with an increased risk of cardiovascular disease and arrhythmias, with the most common arrhythmia being found in the atria of the heart. Little is known about how the normal atria of the heart remodel with age and thus why dysfunction might occur. We report alterations to the atrial systolic Ca2+ transient that have implications for the function of the atrial in the elderly. We describe a novel mechanism by which increased Ca buffering can account for changes to systolic Ca2+ in the old atria. The present study helps us to understand how the processes regulating atrial contraction are remodelled during ageing and provides a basis for future work aiming to understand why dysfunction develops. ABSTRACT Many cardiovascular diseases, including those affecting the atria, are associated with advancing age. Arrhythmias, including those in the atria, can arise as a result of electrical remodelling or alterations in Ca2+ homeostasis. In the atria, age-associated changes in the action potential have been documented. However, little is known about remodelling of intracellular Ca2+ homeostasis in the healthy aged atria. Using single atrial myocytes from young and old Welsh Mountain sheep, we show the free Ca2+ transient amplitude and rate of decay of systolic Ca2+ decrease with age, whereas sarcoplasmic reticulum (SR) Ca content increases. An increase in intracellular Ca buffering explains both the decrease in Ca2+ transient amplitude and decay kinetics in the absence of any change in sarcoendoplasmic reticulum calcium transport ATPase function. Ageing maintained the integrated Ca2+ influx via ICa-L but decreased peak ICa-L . Decreased peak ICa-L was found to be responsible for the age-associated increase in SR Ca content but not the decrease in Ca2+ transient amplitude. Instead, decreased peak ICa-L offsets increased SR load such that Ca2+ release from the SR was maintained during ageing. The results of the present study highlight a novel mechanism by which increased Ca buffering decreases systolic Ca2+ in old atria. Furthermore, for the first time, we have shown that SR Ca content is increased in old atrial myocytes.
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Affiliation(s)
- Jessica D. Clarke
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Central Manchester Foundation Trust, 3.14 Core Technology FacilityUniversity of ManchesterManchesterUK
| | - Jessica L. Caldwell
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Central Manchester Foundation Trust, 3.14 Core Technology FacilityUniversity of ManchesterManchesterUK
| | - Charles M. Pearman
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Central Manchester Foundation Trust, 3.14 Core Technology FacilityUniversity of ManchesterManchesterUK
| | - David A. Eisner
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Central Manchester Foundation Trust, 3.14 Core Technology FacilityUniversity of ManchesterManchesterUK
| | - Andrew W. Trafford
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Central Manchester Foundation Trust, 3.14 Core Technology FacilityUniversity of ManchesterManchesterUK
| | - Katharine M. Dibb
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Central Manchester Foundation Trust, 3.14 Core Technology FacilityUniversity of ManchesterManchesterUK
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Channaveerappa D, Lux JC, Wormwood KL, Heintz TA, McLerie M, Treat JA, King H, Alnasser D, Goodrow RJ, Ballard G, Decker R, Darie CC, Panama BK. Atrial electrophysiological and molecular remodelling induced by obstructive sleep apnoea. J Cell Mol Med 2017; 21:2223-2235. [PMID: 28402037 PMCID: PMC5571519 DOI: 10.1111/jcmm.13145] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/31/2017] [Indexed: 12/19/2022] Open
Abstract
Obstructive sleep apnoea (OSA) affects 9-24% of the adult population. OSA is associated with atrial disease, including atrial enlargement, fibrosis and arrhythmias. Despite the link between OSA and cardiac disease, the molecular changes in the heart which occur with OSA remain elusive. To study OSA-induced cardiac changes, we utilized a recently developed rat model which closely recapitulates the characteristics of OSA. Male Sprague Dawley rats, aged 50-70 days, received surgically implanted tracheal balloons which were inflated to cause transient airway obstructions. Rats were given 60 apnoeas per hour of either 13 sec. (moderate apnoea) or 23 sec. (severe apnoea), 8 hrs per day for 2 weeks. Controls received implants, but no inflations were made. Pulse oximetry measurements were taken at regular intervals, and post-apnoea ECGs were recorded. Rats had longer P wave durations and increased T wave amplitudes following chronic OSA. Proteomic analysis of the atrial tissue homogenates revealed that three of the nine enzymes in glycolysis, and two proteins related to oxidative phosphorylation, were down regulated in the severe apnoea group. Several sarcomeric and pro-hypertrophic proteins were also up regulated with OSA. Chronic OSA causes proteins changes in the atria which suggest impairment of energy metabolism and enhancement of hypertrophy.
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Affiliation(s)
- Devika Channaveerappa
- Biochemistry and Proteomics GroupDepartment of Chemistry and Biomolecular ScienceClarkson UniversityPotsdamNYUSA
| | - Jacob C. Lux
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Kelly L. Wormwood
- Biochemistry and Proteomics GroupDepartment of Chemistry and Biomolecular ScienceClarkson UniversityPotsdamNYUSA
| | - Timothy A. Heintz
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Meredith McLerie
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Jacqueline A. Treat
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Hannah King
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Donia Alnasser
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Robert J. Goodrow
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
| | - Glenn Ballard
- Electrical Engineering TechnologyMohawk Valley Community CollegeUticaNYUSA
| | - Robert Decker
- Electrical Engineering TechnologyMohawk Valley Community CollegeUticaNYUSA
| | - Costel C. Darie
- Biochemistry and Proteomics GroupDepartment of Chemistry and Biomolecular ScienceClarkson UniversityPotsdamNYUSA
| | - Brian K. Panama
- Department of Experimental CardiologyMasonic Medical Research LaboratoryUticaNYUSA
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45
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DeLaughter DM, Bick AG, Wakimoto H, McKean D, Gorham JM, Kathiriya IS, Hinson JT, Homsy J, Gray J, Pu W, Bruneau BG, Seidman JG, Seidman CE. Single-Cell Resolution of Temporal Gene Expression during Heart Development. Dev Cell 2016; 39:480-490. [PMID: 27840107 DOI: 10.1016/j.devcel.2016.10.001] [Citation(s) in RCA: 287] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 03/30/2016] [Accepted: 09/30/2016] [Indexed: 12/29/2022]
Abstract
Activation of complex molecular programs in specific cell lineages governs mammalian heart development, from a primordial linear tube to a four-chamber organ. To characterize lineage-specific, spatiotemporal developmental programs, we performed single-cell RNA sequencing of >1,200 murine cells isolated at seven time points spanning embryonic day 9.5 (primordial heart tube) to postnatal day 21 (mature heart). Using unbiased transcriptional data, we classified cardiomyocytes, endothelial cells, and fibroblast-enriched cells, thus identifying markers for temporal and chamber-specific developmental programs. By harnessing these datasets, we defined developmental ages of human and mouse pluripotent stem-cell-derived cardiomyocytes and characterized lineage-specific maturation defects in hearts of mice with heterozygous mutations in Nkx2.5 that cause human heart malformations. This spatiotemporal transcriptome analysis of heart development reveals lineage-specific gene programs underlying normal cardiac development and congenital heart disease.
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Affiliation(s)
| | - Alexander G Bick
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Hiroko Wakimoto
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - David McKean
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Joshua M Gorham
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Irfan S Kathiriya
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA; Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 92868, USA
| | - John T Hinson
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Jason Homsy
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Jesse Gray
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - William Pu
- Department of Cardiology, Harvard Medical School, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Benoit G Bruneau
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA; Department of Pediatrics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - J G Seidman
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Cardiovascular Division, Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA 02115, USA.
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Abstract
Lung cancer infiltrating the mediastinum is a subset of locally advanced lung tumors for which surgery is not routinely offered. Radical operations that involve removal of adjacent mediastinal structures to obtain free margins may provide a realistic cure. Such extended resections are typically reserved to highly motivated patients seeking more aggressive management, and are only offered following complete evaluation on a case-by-case basis. Positive prognosis depends on complete R0 resection and lack of mediastinal nodal metastases. Careful and exhaustive preoperative planning as well as surgical expertise cannot be overemphasized for successful surgical outcomes. Here we provide a brief summary of the literature as well as our own experience managing these rare and sometimes challenging surgeries.
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Affiliation(s)
- Adnan M Al-Ayoubi
- Department of Thoracic Surgery, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Raja M Flores
- Department of Thoracic Surgery, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Schenone E, Collin A, Gerbeau JF. Numerical simulation of electrocardiograms for full cardiac cycles in healthy and pathological conditions. Int J Numer Method Biomed Eng 2016; 32:e02744. [PMID: 26249327 DOI: 10.1002/cnm.2744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 07/29/2015] [Accepted: 08/03/2015] [Indexed: 06/04/2023]
Abstract
This work is dedicated to the simulation of full cycles of the electrical activity of the heart and the corresponding body surface potential. The model is based on a realistic torso and heart anatomy, including ventricles and atria. One of the specificities of our approach is to model the atria as a surface, which is the kind of data typically provided by medical imaging for thin volumes. The bidomain equations are considered in their usual formulation in the ventricles, and in a surface formulation on the atria. Two ionic models are used: the Courtemanche-Ramirez-Nattel model on the atria and the 'minimal model for human ventricular action potentials' by Bueno-Orovio, Cherry, and Fenton in the ventricles. The heart is weakly coupled to the torso by a Robin boundary condition based on a resistor-capacitor transmission condition. Various electrocardiograms (ECGs) are simulated in healthy and pathological conditions (left and right bundle branch blocks, Bachmann's bundle block, and Wolff-Parkinson-White syndrome). To assess the numerical ECGs, we use several qualitative and quantitative criteria found in the medical literature. Our simulator can also be used to generate the signals measured by a vest of electrodes. This capability is illustrated at the end of the article. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Elisa Schenone
- Sorbonne Universités UPMC, Paris, France
- Inria Paris-Rocquencourt, Paris, France
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48
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Hohendanner F, Maxwell JT, Blatter LA. Cytosolic and nuclear calcium signaling in atrial myocytes: IP3-mediated calcium release and the role of mitochondria. Channels (Austin) 2016; 9:129-38. [PMID: 25891132 DOI: 10.1080/19336950.2015.1040966] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In rabbit atrial myocytes Ca signaling has unique features due to the lack of transverse (t) tubules, the spatial arrangement of mitochondria and the contribution of inositol-1,4,5-trisphosphate (IP3) receptor-induced Ca release (IICR). During excitation-contraction coupling action potential-induced elevation of cytosolic [Ca] originates in the cell periphery from Ca released from the junctional sarcoplasmic reticulum (j-SR) and then propagates by Ca-induced Ca release from non-junctional (nj-) SR toward the cell center. The subsarcolemmal region between j-SR and the first array of nj-SR Ca release sites is devoid of mitochondria which results in a rapid propagation of activation through this domain, whereas the subsequent propagation through the nj-SR network occurs at a velocity typical for a propagating Ca wave. Inhibition of mitochondrial Ca uptake with the Ca uniporter blocker Ru360 accelerates propagation and increases the amplitude of Ca transients (CaTs) originating from nj-SR. Elevation of cytosolic IP3 levels by rapid photolysis of caged IP3 has profound effects on the magnitude of subcellular CaTs with increased Ca release from nj-SR and enhanced CaTs in the nuclear compartment. IP3 uncaging restricted to the nucleus elicites 'mini'-Ca waves that remain confined to this compartment. Elementary IICR events (Ca puffs) preferentially originate in the nucleus in close physical association with membrane structures of the nuclear envelope and the nucleoplasmic reticulum. The data suggest that in atrial myocytes the nucleus is an autonomous Ca signaling domain where Ca dynamics are primarily governed by IICR.
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Key Words
- 2-APB, 2-aminoethoxydiphenyl borate
- AP, action potential
- CICR, Ca-induced Ca release
- CRU, Ca release units
- CT, central
- CaT, Ca transient
- ECC, excitation-contraction coupling
- IICR
- IICR, IP3R-induced Ca release
- IP3
- IP3R, Inositol-1,4,5-trisphosphate receptor
- LCC, L-type Ca channels
- MCU, mitochondrial Ca uniporter
- NE, nuclear envelope
- NFAT, nuclear factor of activated T cells
- NPR, nucleoplasmic reticulum
- RyR, ryanodine receptor
- SR, sarcoplasmic reticulum
- SS, subsarcolemmal
- TF50, time to half-maximal amplitude
- TZ, transition zone.
- [Ca]i, cytosolic Ca concentration
- [Ca]mito, mitochondrial Ca concentration
- atria
- excitation-contraction coupling
- j-SR, junctional SR
- mitochondria
- nj-SR, non-junctional SR
- nuclear calcium
- t-tubule, transverse tubule
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Affiliation(s)
- Felix Hohendanner
- a Department of Molecular Biophysics and Physiology ; Rush University Medical Center ; Chicago , IL USA
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Bragança B, Oliveira-Monteiro N, Ferreirinha F, Lima PA, Faria M, Fontes-Sousa AP, Correia-de-Sá P. Ion Fluxes through KCa2 (SK) and Cav1 (L-type) Channels Contribute to Chronoselectivity of Adenosine A1 Receptor-Mediated Actions in Spontaneously Beating Rat Atria. Front Pharmacol 2016; 7:45. [PMID: 27014060 PMCID: PMC4780064 DOI: 10.3389/fphar.2016.00045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/18/2016] [Indexed: 11/24/2022] Open
Abstract
Impulse generation in supraventricular tissue is inhibited by adenosine and acetylcholine via the activation of A1 and M2 receptors coupled to inwardly rectifying GIRK/KIR3.1/3.4 channels, respectively. Unlike M2 receptors, bradycardia produced by A1 receptors activation predominates over negative inotropy. Such difference suggests that other ion currents may contribute to adenosine chronoselectivity. In isolated spontaneously beating rat atria, blockade of KCa2/SK channels with apamin and Cav1 (L-type) channels with nifedipine or verapamil, sensitized atria to the negative inotropic action of the A1 agonist, R-PIA, without affecting the nucleoside negative chronotropy. Patch-clamp experiments in the whole-cell configuration mode demonstrate that adenosine, via A1 receptors, activates the inwardly-rectifying GIRK/KIR3.1/KIR3.4 current resulting in hyperpolarization of atrial cardiomyocytes, which may slow down heart rate. Conversely, the nucleoside inactivates a small conductance Ca2+-activated KCa2/SK outward current, which eventually reduces the repolarizing force and thereby prolong action potentials duration and Ca2+ influx into cardiomyocytes. Immunolocalization studies showed that differences in A1 receptors distribution between the sinoatrial node and surrounding cardiomyocytes do not afford a rationale for adenosine chronoselectivity. Immunolabelling of KIR3.1, KCa2.2, KCa2.3, and Cav1 was also observed throughout the right atrium. Functional data indicate that while both A1 and M2 receptors favor the opening of GIRK/KIR3.1/3.4 channels modulating atrial chronotropy, A1 receptors may additionally restrain KCa2/SK activation thereby compensating atrial inotropic depression by increasing the time available for Ca2+ influx through Cav1 (L-type) channels.
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Affiliation(s)
- Bruno Bragança
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto (UP) Porto, Portugal
| | - Nádia Oliveira-Monteiro
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto (UP) Porto, Portugal
| | - Fátima Ferreirinha
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto (UP) Porto, Portugal
| | - Pedro A Lima
- Departamento de Química e Bioquímica, Faculdade de Ciências, Centro de Química e Bioquímica, Universidade de Lisboa Lisboa, Portugal
| | - Miguel Faria
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto (UP) Porto, Portugal
| | - Ana P Fontes-Sousa
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto (UP) Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto (UP) Porto, Portugal
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Meana C, Rubín JM, Bordallo C, Suárez L, Bordallo J, Sánchez M. Correlation between endogenous polyamines in human cardiac tissues and clinical parameters in patients with heart failure. J Cell Mol Med 2015; 20:302-12. [PMID: 26578237 PMCID: PMC4727566 DOI: 10.1111/jcmm.12674] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 08/03/2015] [Indexed: 12/20/2022] Open
Abstract
Polyamines contribute to several physiological and pathological processes, including cardiac hypertrophy in experimental animals. This involves an increase in ornithine decarboxylase (ODC) activity and intracellular polyamines associated with cyclic adenosine monophosphate (cAMP) increases. The aim of the study was to establish the role of these in the human heart in living patients. For this, polyamines (by high performance liquid chromatography) and the activity of ODC and N1‐acetylpolyamine oxidases (APAO) were determined in the right atrial appendage of 17 patients undergoing extracorporeal circulation to correlate with clinical parameters. There existed enzymatic activity associated with the homeostasis of polyamines. Left atria size was positively associated with ODC (r = 0.661, P = 0.027) and negatively with APAO‐N1‐acetylspermine (r = −0.769, P = 0.026), suggesting that increased levels of polyamines are associated with left atrial hemodynamic overload. Left ventricular ejection fraction (LVEF) and heart rate were positively associated with spermidine (r = 0.690, P = 0.003; r = 0.590, P = 0.021) and negatively with N1‐acetylspermidine (r = −0.554, P = 0.032; r = −0.644, P = 0.018). LVEF was negatively correlated with cAMP levels (r = −0.835, P = 0.001) and with cAMP/ODC (r = −0.794, P = 0.011), cAMP/spermidine (r = −0.813, P = 0.001) and cAMP/spermine (r = −0.747, P = 0.003) ratios. Abnormal LVEF patients showed decreased ODC activity and spermidine, and increased N1‐acetylspermidine, and cAMP. Spermine decreased in congestive heart failure patients. The trace amine isoamylamine negatively correlated with septal wall thickness (r = −0.634, P = 0.008) and was increased in cardiac heart failure. The results indicated that modifications in polyamine homeostasis might be associated with cardiac function and remodelling. Increased cAMP might have a deleterious effect on function. Further studies should confirm these findings and the involvement of polyamines in different stages of heart failure.
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Affiliation(s)
- Clara Meana
- Farmacología, Departamento de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - José Manuel Rubín
- Servicio de Cardiología, Hospital Universitario Central de Asturias, Asturias, Spain
| | - Carmen Bordallo
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Oviedo, Spain.,Instituto Universitario de Oncología del Principado de Asturias, Asturias, Spain
| | - Lorena Suárez
- Instituto Universitario de Oncología del Principado de Asturias, Asturias, Spain
| | - Javier Bordallo
- Farmacología, Departamento de Medicina, Universidad de Oviedo, Oviedo, Spain.,Instituto Universitario de Oncología del Principado de Asturias, Asturias, Spain
| | - Manuel Sánchez
- Farmacología, Departamento de Medicina, Universidad de Oviedo, Oviedo, Spain.,Instituto Universitario de Oncología del Principado de Asturias, Asturias, Spain
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