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Sridhar S, Clayton RH. Fibroblast mediated dynamics in diffusively uncoupled myocytes: a simulation study using 2-cell motifs. Sci Rep 2024; 14:4493. [PMID: 38396245 PMCID: PMC10891142 DOI: 10.1038/s41598-024-54564-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
In healthy hearts myocytes are typically coupled to nearest neighbours through gap junctions. Under pathological conditions such as fibrosis, or in scar tissue, or across ablation lines myocytes can uncouple from their neighbours. Electrical conduction may still occur via fibroblasts that not only couple proximal myocytes but can also couple otherwise unconnected regions. We hypothesise that such coupling can alter conduction between myocytes via introduction of delays or by initiation of premature stimuli that can potentially result in reentry or conduction blocks. To test this hypothesis we have developed several 2-cell motifs and investigated the effect of fibroblast mediated electrical coupling between uncoupled myocytes. We have identified various regimes of myocyte behaviour that depend on the strength of gap-junctional conductance, connection topology, and parameters of the myocyte and fibroblast models. These motifs are useful in developing a mechanistic understanding of long-distance coupling on myocyte dynamics and enable the characterisation of interaction between different features such as myocyte and fibroblast properties, coupling strengths and pacing period. They are computationally inexpensive and allow for incorporation of spatial effects such as conduction velocity. They provide a framework for constructing scar tissue boundaries and enable linking of cellular level interactions with scar induced arrhythmia.
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Affiliation(s)
- S Sridhar
- Department of Computer Science, University of Sheffield, Sheffield, UK.
| | - Richard H Clayton
- Department of Computer Science, University of Sheffield, Sheffield, UK
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2
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Tsuji Y, Ogata T, Mochizuki K, Tamura S, Morishita Y, Takamatsu T, Matoba S, Tanaka H. Myofibroblasts impair myocardial impulse propagation by heterocellular connexin43 gap-junctional coupling through micropores. Front Physiol 2024; 15:1352911. [PMID: 38465264 PMCID: PMC10920281 DOI: 10.3389/fphys.2024.1352911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 02/07/2024] [Indexed: 03/12/2024] Open
Abstract
Aim: Composite population of myofibroblasts (MFs) within myocardial tissue is known to alter impulse propagation, leading to arrhythmias. However, it remains unclear whether and how MFs alter their propagation patterns when contacting cardiomyocytes (CMs) without complex structural insertions in the myocardium. We attempted to unveil the effects of the one-sided, heterocellular CM-MF connection on the impulse propagation of CM monolayers without the spatial insertion of MFs as an electrical or mechanical obstacle. Methods and results: We evaluated fluo8-based spatiotemporal patterns in impulse propagation of neonatal rat CM monolayers cultured on the microporous membrane having 8-μm diameter pores with co-culture of MFs or CMs on the reverse membrane side (CM-MF model or CM-CM model, respectively). During consecutive pacing at 1 or 2 Hz, the CM monolayers exhibited forward impulse propagation from the pacing site with a slower conduction velocity (θ) and a larger coefficient of directional θ variation in the CM-MF model than that in the CM-CM model in a frequency-dependent manner (2 Hz >1 Hz). The localized placement of an MF cluster on the reverse side resulted in an abrupt segmental depression of the impulse propagation of the upper CM layer, causing a spatiotemporally non-uniform pattern. Dye transfer of the calcein loaded in the upper CM layer to the lower MF layer was attenuated by the gap-junction inhibitor heptanol. Immunocytochemistry identified definitive connexin 43 (Cx43) between the CMs and MFs in the membrane pores. MF-selective Cx43 knockdown in the MF layer improved both the velocity and uniformity of propagation in the CM monolayer. Conclusion: Heterocellular Cx43 gap junction coupling of CMs with MFs alters the spatiotemporal patterns of myocardial impulse propagation, even in the absence of spatially interjacent and mechanosensitive modulations by MFs. Moreover, MFs can promote pro-arrhythmogenic impulse propagation when in face-to-face contact with the myocardium that arises in the healing infarct border zone.
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Affiliation(s)
- Yumika Tsuji
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takehiro Ogata
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kentaro Mochizuki
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shoko Tamura
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuma Morishita
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tetsuro Takamatsu
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Medical Photonics, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hideo Tanaka
- Department of Pathology and Cell Regulation and, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Faculty of Health and Medical Sciences, Kyoto University of Advanced Science, Kyoto, Japan
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3
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Chen YC, Shih CL, Wu CL, Fang YH, So EC, Wu SN. Exploring the Impact of BK Ca Channel Function in Cellular Membranes on Cardiac Electrical Activity. Int J Mol Sci 2024; 25:1537. [PMID: 38338830 PMCID: PMC10855144 DOI: 10.3390/ijms25031537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/14/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
This review paper delves into the current body of evidence, offering a thorough analysis of the impact of large-conductance Ca2+-activated K+ (BKCa or BK) channels on the electrical dynamics of the heart. Alterations in the activity of BKCa channels, responsible for the generation of the overall magnitude of Ca2+-activated K+ current at the whole-cell level, occur through allosteric mechanisms. The collaborative interplay between membrane depolarization and heightened intracellular Ca2+ ion concentrations collectively contribute to the activation of BKCa channels. Although fully developed mammalian cardiac cells do not exhibit functional expression of these ion channels, evidence suggests their presence in cardiac fibroblasts that surround and potentially establish close connections with neighboring cardiac cells. When cardiac cells form close associations with fibroblasts, the high single-ion conductance of these channels, approximately ranging from 150 to 250 pS, can result in the random depolarization of the adjacent cardiac cell membranes. While cardiac fibroblasts are typically electrically non-excitable, their prevalence within heart tissue increases, particularly in the context of aging myocardial infarction or atrial fibrillation. This augmented presence of BKCa channels' conductance holds the potential to amplify the excitability of cardiac cell membranes through effective electrical coupling between fibroblasts and cardiomyocytes. In this scenario, this heightened excitability may contribute to the onset of cardiac arrhythmias. Moreover, it is worth noting that the substances influencing the activity of these BKCa channels might influence cardiac electrical activity as well. Taken together, the BKCa channel activity residing in cardiac fibroblasts may contribute to cardiac electrical function occurring in vivo.
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Affiliation(s)
- Yin-Chia Chen
- Division of Cardiovascular Surgery, Department of Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Chia-Lung Shih
- Clinical Research Center, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60056, Taiwan
| | - Chao-Liang Wu
- Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Yi-Hsien Fang
- Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70403, Taiwan
| | - Edmund Cheung So
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan 70965, Taiwan
| | - Sheng-Nan Wu
- Department of Research and Education, An Nan Hospital, China Medical University, Tainan 70965, Taiwan
- School of Medicine, College of Medicine, National Sun Yat-sen University, Kaohsiung 80421, Taiwan
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4
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Simon-Chica A, Wülfers EM, Kohl P. Nonmyocytes as electrophysiological contributors to cardiac excitation and conduction. Am J Physiol Heart Circ Physiol 2023; 325:H475-H491. [PMID: 37417876 PMCID: PMC10538996 DOI: 10.1152/ajpheart.00184.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/22/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023]
Abstract
Although cardiac action potential (AP) generation and propagation have traditionally been attributed exclusively to cardiomyocytes (CM), other cell types in the heart are also capable of forming electrically conducting junctions. Interactions between CM and nonmyocytes (NM) enable and modulate each other's activity. This review provides an overview of the current understanding of heterocellular electrical communication in the heart. Although cardiac fibroblasts were initially thought to be electrical insulators, recent studies have demonstrated that they form functional electrical connections with CM in situ. Other NM, such as macrophages, have also been recognized as contributing to cardiac electrophysiology and arrhythmogenesis. Novel experimental tools have enabled the investigation of cell-specific activity patterns in native cardiac tissue, which is expected to yield exciting new insights into the development of novel or improved diagnostic and therapeutic strategies.
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Affiliation(s)
- Ana Simon-Chica
- Novel Arrhythmogenic Mechanisms Program, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Eike M Wülfers
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Gent, Belgium
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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5
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Vuorenpää H, Björninen M, Välimäki H, Ahola A, Kroon M, Honkamäki L, Koivumäki JT, Pekkanen-Mattila M. Building blocks of microphysiological system to model physiology and pathophysiology of human heart. Front Physiol 2023; 14:1213959. [PMID: 37485060 PMCID: PMC10358860 DOI: 10.3389/fphys.2023.1213959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/26/2023] [Indexed: 07/25/2023] Open
Abstract
Microphysiological systems (MPS) are drawing increasing interest from academia and from biomedical industry due to their improved capability to capture human physiology. MPS offer an advanced in vitro platform that can be used to study human organ and tissue level functions in health and in diseased states more accurately than traditional single cell cultures or even animal models. Key features in MPS include microenvironmental control and monitoring as well as high biological complexity of the target tissue. To reach these qualities, cross-disciplinary collaboration from multiple fields of science is required to build MPS. Here, we review different areas of expertise and describe essential building blocks of heart MPS including relevant cardiac cell types, supporting matrix, mechanical stimulation, functional measurements, and computational modelling. The review presents current methods in cardiac MPS and provides insights for future MPS development with improved recapitulation of human physiology.
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Affiliation(s)
- Hanna Vuorenpää
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Adult Stem Cell Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Research, Development and Innovation Centre, Tampere University Hospital, Tampere, Finland
| | - Miina Björninen
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Adult Stem Cell Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Research, Development and Innovation Centre, Tampere University Hospital, Tampere, Finland
| | - Hannu Välimäki
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Micro- and Nanosystems Research Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Antti Ahola
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Computational Biophysics and Imaging Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Mart Kroon
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Biomaterials and Tissue Engineering Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Laura Honkamäki
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Neuro Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Jussi T. Koivumäki
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Computational Biophysics and Imaging Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Mari Pekkanen-Mattila
- Centre of Excellence in Body-on-Chip Research (CoEBoC), BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Heart Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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6
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Li G, Yang J, Zhang D, Wang X, Han J, Guo X. Research Progress of Myocardial Fibrosis and Atrial Fibrillation. Front Cardiovasc Med 2022; 9:889706. [PMID: 35958428 PMCID: PMC9357935 DOI: 10.3389/fcvm.2022.889706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/10/2022] [Indexed: 12/04/2022] Open
Abstract
With the aging population and the increasing incidence of basic illnesses such as hypertension and diabetes (DM), the incidence of atrial fibrillation (AF) has increased significantly. AF is the most common arrhythmia in clinical practice, which can cause heart failure (HF) and ischemic stroke (IS), increasing disability and mortality. Current studies point out that myocardial fibrosis (MF) is one of the most critical substrates for the occurrence and maintenance of AF. Although myocardial biopsy is the gold standard for evaluating MF, it is rarely used in clinical practice because it is an invasive procedure. In addition, serological indicators and imaging methods have also been used to evaluate MF. Nevertheless, the accuracy of serological markers in evaluating MF is controversial. This review focuses on the pathogenesis of MF, serological evaluation, imaging evaluation, and anti-fibrosis treatment to discuss the existing problems and provide new ideas for MF and AF evaluation and treatment.
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Affiliation(s)
- Guangling Li
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
| | - Jing Yang
- Department of Pathology, Gansu Provincial Hospital, Lanzhou, China
| | - Demei Zhang
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
| | - Xiaomei Wang
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
| | - Jingjing Han
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
| | - Xueya Guo
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
- *Correspondence: Xueya Guo,
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7
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Husti Z, Varró A, Baczkó I. Arrhythmogenic Remodeling in the Failing Heart. Cells 2021; 10:cells10113203. [PMID: 34831426 PMCID: PMC8623396 DOI: 10.3390/cells10113203] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 12/12/2022] Open
Abstract
Chronic heart failure is a clinical syndrome with multiple etiologies, associated with significant morbidity and mortality. Cardiac arrhythmias, including ventricular tachyarrhythmias and atrial fibrillation, are common in heart failure. A number of cardiac diseases including heart failure alter the expression and regulation of ion channels and transporters leading to arrhythmogenic electrical remodeling. Myocardial hypertrophy, fibrosis and scar formation are key elements of arrhythmogenic structural remodeling in heart failure. In this article, the mechanisms responsible for increased arrhythmia susceptibility as well as the underlying changes in ion channel, transporter expression and function as well as alterations in calcium handling in heart failure are discussed. Understanding the mechanisms of arrhythmogenic remodeling is key to improving arrhythmia management and the prevention of sudden cardiac death in patients with heart failure.
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Affiliation(s)
- Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6720 Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
- Correspondence:
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8
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Al-Hejailan RS, Bakheet RH, Al-Saud MM, Al-Jufan MB, Al-Hindas HM, Al-Qattan SM, Al-Muhanna MK, Parhar RS, Conca W, Hansmann J, Collison KS, Walles H, Al-Mohanna FA. Toward allogenizing a xenograft: Xenogeneic cardiac scaffolds recellularized with human-induced pluripotent stem cells do not activate human naïve neutrophils. J Biomed Mater Res B Appl Biomater 2021; 110:691-701. [PMID: 34619017 DOI: 10.1002/jbm.b.34948] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/31/2021] [Accepted: 09/22/2021] [Indexed: 11/12/2022]
Abstract
The limited availability of human donor organs suitable for transplantation has resulted in ever-increasing patient waiting lists globally. Xenotransplantation is considered a potential option, but is yet to reach clinical practice. Although remarkable progress has been made in overcoming immunological rejection, issues with functionality are still to be resolved. Bioengineering approaches have been used to create cardiac tissues with optimized functions. The use of decellularized xenogeneic cardiac tissues seeded with donor-derived cardiac cells may prove to be a viable strategy as supporting structures of the native tissue such as vasculature can be utilized. Here we used sequential perfusion to decellularize adult rat hearts. The acellular scaffolds were reseeded with human endothelial cells, human fibroblasts, human mesenchymal stem cells, and cardiac cells derived from human-induced pluripotent stem cells. The ability of the resultant recellularized rat scaffolds to activate human naïve neutrophils in vitro was investigated to measure xenogeneic recognition. Our results demonstrate that in contrast to cadaveric xenogeneic hearts, acellular and recellularized xenogeneic scaffolds did not activate human naïve neutrophils and suggest that decellularization removes the xenogeneic antigens that lead to human naïve neutrophil activation thus allowing human cells to populate the now "allogenized" xenogeneic scaffolds.
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Affiliation(s)
- Reem S Al-Hejailan
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.,Department of Heart Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Razan H Bakheet
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mashael M Al-Saud
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | | | - Hussain M Al-Hindas
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Somaya M Al-Qattan
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Muhanna K Al-Muhanna
- Tissue Engineering and Regenerative Medicine (TERM), Würzburg University, Würzburg, Germany
| | - Ranjit S Parhar
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Walter Conca
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Jan Hansmann
- Department of Heart Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Kate S Collison
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Heike Walles
- Department of Heart Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Futwan A Al-Mohanna
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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9
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Stewart L, Turner NA. Channelling the Force to Reprogram the Matrix: Mechanosensitive Ion Channels in Cardiac Fibroblasts. Cells 2021; 10:990. [PMID: 33922466 PMCID: PMC8145896 DOI: 10.3390/cells10050990] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/13/2021] [Accepted: 04/21/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac fibroblasts (CF) play a pivotal role in preserving myocardial function and integrity of the heart tissue after injury, but also contribute to future susceptibility to heart failure. CF sense changes to the cardiac environment through chemical and mechanical cues that trigger changes in cellular function. In recent years, mechanosensitive ion channels have been implicated as key modulators of a range of CF functions that are important to fibrotic cardiac remodelling, including cell proliferation, myofibroblast differentiation, extracellular matrix turnover and paracrine signalling. To date, seven mechanosensitive ion channels are known to be functional in CF: the cation non-selective channels TRPC6, TRPM7, TRPV1, TRPV4 and Piezo1, and the potassium-selective channels TREK-1 and KATP. This review will outline current knowledge of these mechanosensitive ion channels in CF, discuss evidence of the mechanosensitivity of each channel, and detail the role that each channel plays in cardiac remodelling. By better understanding the role of mechanosensitive ion channels in CF, it is hoped that therapies may be developed for reducing pathological cardiac remodelling.
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Affiliation(s)
| | - Neil A. Turner
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds LS2 9JT, UK;
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10
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Changes in cardiac conduction time following cardiac resynchronization therapy: rationale and design of the RECOVER study. J Interv Card Electrophysiol 2021; 63:303-309. [PMID: 33774800 DOI: 10.1007/s10840-021-00979-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 03/10/2021] [Indexed: 12/23/2022]
Abstract
BACKGROUND It has been known that ventricular conduction delays play a key role in the cardiac resynchronization therapy (CRT) response of patients with advanced heart failure (HF). However, no study to our knowledge has yet evaluated the serial changes in conduction times measured between different electrodes of CRT devices. METHODS AND RESULTS The Reduction or Extension of Conduction Time with Ventricular Electromechanical Remodeling (RECOVER) study (NCT04397224) was designed to investigate serial changes in interelectrode conduction times and to elucidate their prognostic value. We plan to enroll 100 patients implanted with CRT systems with endocardial quadripolar left ventricular leads. Patients will be scheduled for follow-up every 3 months over a period of 2 years, where they will undergo measurement of interelectrode conduction times to evaluate their serial changes. The primary outcome of the RECOVER study is the correlation between the degree of conduction time changes and the CRT response as defined by echocardiography. The time course and prognostic value of the serial changes in conduction times will be investigated as well. CONCLUSION The RECOVER study is investigating whether serial changes in interelectrode conduction times can be useful parameters in predicting the CRT response or detecting worsening HF at an early stage.
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11
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Ghosh N, Garg I, Srivastava S, Kumar B. Influence of integrins on thrombus formation: a road leading to the unravelling of DVT. Mol Cell Biochem 2021; 476:1489-1504. [PMID: 33398665 DOI: 10.1007/s11010-020-03961-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/23/2020] [Indexed: 01/18/2023]
Abstract
Integrins are a group of transmembrane glycoprotein receptors that are responsible for platelet activation through bidirectional signalling. These receptors have left their footprints in various cellular events and have intrigued many groups of scientists that have led to some significant discoveries. A lot of the recent understanding of haemostasis has been possible due to the integrins filling the gaps in between several cellular mechanism. Apart from this, other important functions carried out by integrins are growth and maturation of cardiomyocytes, mechano-transduction, and interaction with actin cytoskeleton. The signalling cascade for integrin activation involves certain intracellular interacting proteins, which initiates the step-by-step activation procedure through 'inside-out' signalling. The signalling cascade gets activated through 'outside-in' signalling with the involvement of agonists such as ADP, Fibronectin, Vitronectin, and so on. This is a crucial step for the downstream processes of platelet spreading, followed by aggregation, clot progression and finally thrombus formation. Researchers throughout the world have shown direct relation of integrins with CVD and cardiac remodelling. The present review aims to summarize the information available so far on the involvement of integrins in thrombosis and its relationship to DVT. This information could be a bedrock of hidden answers to several questions on pathogenesis of deep vein thrombosis.
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Affiliation(s)
- Nilanjana Ghosh
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Iti Garg
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India.
| | - Swati Srivastava
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Bhuvnesh Kumar
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
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12
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Zhao Y, Iyer S, Tavanaei M, Nguyen NT, Lin A, Nguyen TP. Proarrhythmic Electrical Remodeling by Noncardiomyocytes at Interfaces With Cardiomyocytes Under Oxidative Stress. Front Physiol 2021; 11:622613. [PMID: 33603677 PMCID: PMC7884825 DOI: 10.3389/fphys.2020.622613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Life-threatening ventricular arrhythmias, typically arising from interfaces between fibrosis and surviving cardiomyocytes, are feared sequelae of structurally remodeled hearts under oxidative stress. Incomplete understanding of the proarrhythmic electrical remodeling by fibrosis limits the development of novel antiarrhythmic strategies. To define the mechanistic determinants of the proarrhythmia in electrical crosstalk between cardiomyocytes and noncardiomyocytes, we developed a novel in vitro model of interface between neonatal rat ventricular cardiomyocytes (NRVMs) and controls [NRVMs or connexin43 (Cx43)-deficient HeLa cells] vs. Cx43+ noncardiomyocytes [aged rat ventricular myofibroblasts (ARVFs) or HeLaCx43 cells]. We performed high-speed voltage-sensitive optical imaging at baseline and following acute H2O2 exposure. In NRVM-NRVM and NRVM-HeLa controls, no arrhythmias occurred under either experimental condition. In the NRVM-ARVF and NRVM-HeLaCx43 groups, Cx43+ noncardiomyocytes enabled passive decremental propagation of electrical impulses and impaired NRVM activation and repolarization, thereby slowing conduction and prolonging action potential duration. Following H2O2 exposure, arrhythmia triggers, automaticity, and non-reentrant and reentrant arrhythmias emerged. This study reveals that myofibroblasts (which generate cardiac fibrosis) and other noncardiomyocytes can induce not only structural remodeling but also electrical remodeling and that electrical remodeling by noncardiomyocytes can be particularly arrhythmogenic in the presence of an oxidative burst. Synergistic electrical remodeling between H2O2 and noncardiomyocytes may account for the clinical arrhythmogenicity of myofibroblasts at fibrotic interfaces with cardiomyocytes in ischemic/non-ischemic cardiomyopathies. Understanding the enhanced arrhythmogenicity of synergistic electrical remodeling by H2O2 and noncardiomyocytes may guide novel safe-by-design antiarrhythmic strategies for next-generation iatrogenic interfaces between surviving native cardiomyocytes and exogenous stem cells or engineered tissues in cardiac regenerative therapies.
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Affiliation(s)
- Yali Zhao
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Shankar Iyer
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Maryam Tavanaei
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Nicole T Nguyen
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Andrew Lin
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Thao P Nguyen
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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Marta Varela, Roy A, Lee J. A survey of pathways for mechano-electric coupling in the atria. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 159:136-145. [PMID: 33053408 PMCID: PMC7848589 DOI: 10.1016/j.pbiomolbio.2020.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 09/09/2020] [Accepted: 09/29/2020] [Indexed: 11/26/2022]
Abstract
Mechano-electric coupling (MEC) in atrial tissue has received sparse investigation to date, despite the well-known association between chronic atrial dilation and atrial fibrillation (AF). Of note, no fewer than six different mechanisms pertaining to stretch-activated channels, cellular capacitance and geometric effects have been identified in the literature as potential players. In this mini review, we briefly survey each of these pathways to MEC. We then perform computational simulations using single cell and tissue models in presence of various stretch regimes and MEC pathways. This allows us to assess the relative significance of each pathway in determining action potential duration, conduction velocity and rotor stability. For chronic atrial stretch, we find that stretch-induced alterations in membrane capacitance decrease conduction velocity and increase action potential duration, in agreement with experimental findings. In the presence of time-dependent passive atrial stretch, stretch-activated channels play the largest role, leading to after-depolarizations and rotor hypermeandering. These findings suggest that physiological atrial stretches, such as passive stretch during the atrial reservoir phase, may play an important part in the mechanisms of atrial arrhythmogenesis. Passive strains caused by ventricular contraction need to be considered when incorporating mechano-electro feedback in atrial electrophysiology models. In chronic stretch, stretch-induced capacitance changes dominate. Chronic stretch leads to an increase in action potential duration and a reduction in conduction velocity, consistent with experimental studies. In the presence of passive stretch, stretch-activated channels can induce delayed after-depolarisations and lead to rotor hypermeandering. Mechano-electro feedback is thus likely to have implications for the genesis and maintenance of atrial arrhythmias.
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Affiliation(s)
- Marta Varela
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK; Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK.
| | - Aditi Roy
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Computing, University of Oxford, Oxford, UK
| | - Jack Lee
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
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14
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Ravelli F, Masè M. MicroRNAs: New contributors to mechano-electric coupling and atrial fibrillation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 159:146-156. [PMID: 33011190 DOI: 10.1016/j.pbiomolbio.2020.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 09/17/2020] [Accepted: 09/27/2020] [Indexed: 12/29/2022]
Abstract
Atrial fibrillation (AF) is a multifactorial disease, which often occurs in the presence of underlying cardiac abnormalities and is supported by electrophysiological and structural alterations, generally referred to as atrial remodeling. Abnormal substrates are commonly encountered in various conditions that predispose to AF, such as hypertension, heart failure, obesity, and sleep apnea, in which atrial stretch plays a key mechanistic role. Emerging evidence suggests a role for microRNAs (small non-coding RNAs) in the pathogenesis of AF, where they can act as post-transcriptional regulators of the genes involved in atrial remodeling. This review summarizes the experimental and clinical evidence that supports the role of microRNAs in the modulation of atrial electrical and structural remodeling with a focus on overload-induced atrial alterations, and discusses the potential contribution of microRNAs to mechano-electrical coupling and AF.
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Affiliation(s)
- Flavia Ravelli
- Laboratory of Biophysics and Biosignals, University of Trento, Trento, Italy.
| | - Michela Masè
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy; Healthcare Research and Innovation Program, IRCS-HTA, Bruno Kessler Foundation, Trento, Italy
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15
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Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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Zhan H, Zhang J, Jiao A, Wang Q. Stretch-activated current in human atrial myocytes and Na + current and mechano-gated channels' current in myofibroblasts alter myocyte mechanical behavior: a computational study. Biomed Eng Online 2019; 18:104. [PMID: 31653259 PMCID: PMC6814973 DOI: 10.1186/s12938-019-0723-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 10/16/2019] [Indexed: 12/19/2022] Open
Abstract
Background The activation of stretch-activated channels (SACs) in cardiac myocytes, which changes the phases of action potential repolarization, is proven to be highly efficient for the conversion of atrial fibrillation. The expression of Na+ current in myofibroblasts (Mfbs) regenerates myocytes’ action potentials, suggesting that Mfbs play an active role in triggering cardiac rhythm disturbances. Moreover, the excitation of mechano-gated channels (MGCs) in Mfbs depolarizes their membrane potential and contributes to the increased risk of post-infarct arrhythmia. Although these electrophysiological mechanisms have been largely known, the roles of these currents in cardiac mechanics are still debated. In this study, we aimed to investigate the mechanical influence of these currents via mathematical modeling. A novel mathematical model was developed by integrating models of human atrial myocyte (including the stretch-activated current, Ca2+–force relation, and mechanical behavior of a single segment) and Mfb (including our formulation of Na+ current and mechano-gated channels’ current). The effects of the changes in basic cycle length, number of coupled Mfbs and intercellular coupling conductance on myocyte mechanical properties were compared. Results Our results indicated that these three currents significantly regulated myocyte mechanical parameters. In isosarcometric contraction, these currents increased segment force by 13.8–36.6% and dropped element length by 12.1–31.5%. In isotonic contraction, there are 2.7–5.9% growth and 0.9–24% reduction. Effects of these currents on the extremum of myocyte mechanical parameters become more significant with the increase of basic cycle length, number of coupled Mfbs and intercellular coupling conductance. Conclusions The results demonstrated that stretch-activated current in myocytes and Na+ current and mechano-gated channels’ current in Mfbs significantly influenced myocyte mechanical behavior and should be considered in future cardiac mechanical mathematical modeling.
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Affiliation(s)
- Heqing Zhan
- College of Medical Information, Hainan Medical University, Haikou, 571199, China.
| | - Jingtao Zhang
- Cardiac Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Beijing, 100037, China
| | - Anquan Jiao
- College of Medical Information, Hainan Medical University, Haikou, 571199, China
| | - Qin Wang
- College of Medical Information, Hainan Medical University, Haikou, 571199, China
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17
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Vernemmen I, De Clercq D, Decloedt A, Vera L, Van Steenkiste G, van Loon G. Atrial premature depolarisations five days post electrical cardioversion are related to atrial fibrillation recurrence risk in horses. Equine Vet J 2019; 52:374-378. [PMID: 31583742 DOI: 10.1111/evj.13186] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/29/2019] [Indexed: 02/01/2023]
Abstract
BACKGROUND The number of atrial premature depolarisations (APDs) is a known risk factor for atrial fibrillation (AF) recurrence in humans. OBJECTIVES To evaluate if the number of APDs over a 24-h period 5 days post cardioversion predicts AF recurrence within 1 year in horses, taking the multifactorial nature of AF into account. STUDY DESIGN Retrospective case series. METHODS Eighty horses met these inclusion criteria: first AF episode, no AF recurrence within 5 days post cardioversion, cardioversion by transvenous electrical cardioversion (TVEC), 24-h ECG recording and echocardiographic examination 5 days post cardioversion, no antiarrhythmic treatment during the ECG recording and follow-up of minimum 1 year. To compare the APD burden between the recurrence and non-recurrence group a Mann-Whitney U test was used. A multivariable survival model was built to identify additional risk factors for AF recurrence. RESULTS The patient population mainly consisted of Warmbloods (93%). Twenty-six horses (33%) experienced AF recurrence within 1 year. The number of APDs (median [range]) was significantly higher (P = 0.01) in the recurrence group (15 [1-152]) compared with the non-recurrence group (7 [0-304]). In the multivariable survival model, APDs ≥25/24 h (hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.2-6.8, P = 0.02), mitral regurgitation (HR 8.6, 95% CI 2.6-28.9, P<0.001), left atrial active fractional area change ≤9.6% (HR 2.6, 95% CI 1.0-6.5, P = 0.04) and lower body weight (HR 0.99, 95% CI 0.98-0.99, P = 0.001) were significantly associated with AF recurrence. MAIN LIMITATIONS This study did not evaluate early AF recurrence within 5 days. The results cannot necessarily be extrapolated to other treatment methods, as only horses converted by TVEC were included. CONCLUSIONS The APD burden 5 days post cardioversion could be a useful predictive value for AF recurrence within 1 year in horses. However, other factors such as mitral regurgitation and atrial contractile function must also be taken into account.
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Affiliation(s)
- I Vernemmen
- Equine Cardioteam Ghent University, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - D De Clercq
- Equine Cardioteam Ghent University, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - A Decloedt
- Equine Cardioteam Ghent University, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - L Vera
- Equine Cardioteam Ghent University, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - G Van Steenkiste
- Equine Cardioteam Ghent University, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - G van Loon
- Equine Cardioteam Ghent University, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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18
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Du'o'ng MT, Holz D, Alkassar M, Dittrich S, Leyendecker S. Interaction of the Mechano-Electrical Feedback With Passive Mechanical Models on a 3D Rat Left Ventricle: A Computational Study. Front Physiol 2019; 10:1041. [PMID: 31607936 PMCID: PMC6769123 DOI: 10.3389/fphys.2019.01041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 07/30/2019] [Indexed: 01/28/2023] Open
Abstract
In this paper, we are investigating the interaction between different passive material models and the mechano-electrical feedback (MEF) in cardiac modeling. Various types of passive mechanical laws (nearly incompressible/compressible, polynomial/exponential-type, transversally isotropic/orthotropic material models) are integrated in a fully coupled electromechanical model in order to study their specific influence on the overall MEF behavior. Our computational model is based on a three-dimensional (3D) geometry of a healthy rat left ventricle reconstructed from magnetic resonance imaging (MRI). The electromechanically coupled problem is solved using a fully implicit finite element-based approach. The effects of different passive material models on the MEF are studied with the help of numerical examples. It turns out that there is a significant difference between the behavior of the MEF for compressible and incompressible material models. Numerical results for the incompressible models exhibit that a change in the electrophysiology can be observed such that the transmembrane potential (TP) is unable to reach the resting state in the repolarization phase, and this leads to non-zero relaxation deformations. The most significant and strongest effects of the MEF on the rat cardiac muscle response are observed for the exponential passive material law.
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Affiliation(s)
- Minh Tuấn Du'o'ng
- Chair of Applied Dynamics, University of Erlangen-Nuremberg, Erlangen, Germany.,School of Mechanical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - David Holz
- Chair of Applied Dynamics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Muhannad Alkassar
- Pediatric Cardiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Sven Dittrich
- Pediatric Cardiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Sigrid Leyendecker
- Chair of Applied Dynamics, University of Erlangen-Nuremberg, Erlangen, Germany
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19
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Zaccaro A, Piarulli A, Laurino M, Garbella E, Menicucci D, Neri B, Gemignani A. How Breath-Control Can Change Your Life: A Systematic Review on Psycho-Physiological Correlates of Slow Breathing. Front Hum Neurosci 2018; 12:353. [PMID: 30245619 PMCID: PMC6137615 DOI: 10.3389/fnhum.2018.00353] [Citation(s) in RCA: 203] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/17/2018] [Indexed: 12/13/2022] Open
Abstract
Background: The psycho-physiological changes in brain-body interaction observed in most of meditative and relaxing practices rely on voluntary slowing down of breath frequency. However, the identification of mechanisms linking breath control to its psychophysiological effects is still under debate. This systematic review is aimed at unveiling psychophysiological mechanisms underlying slow breathing techniques (<10 breaths/minute) and their effects on healthy subjects. Methods: A systematic search of MEDLINE and SCOPUS databases, using keywords related to both breathing techniques and to their psychophysiological outcomes, focusing on cardio-respiratory and central nervous system, has been conducted. From a pool of 2,461 abstracts only 15 articles met eligibility criteria and were included in the review. The present systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: The main effects of slow breathing techniques cover autonomic and central nervous systems activities as well as the psychological status. Slow breathing techniques promote autonomic changes increasing Heart Rate Variability and Respiratory Sinus Arrhythmia paralleled by Central Nervous System (CNS) activity modifications. EEG studies show an increase in alpha and a decrease in theta power. Anatomically, the only available fMRI study highlights increased activity in cortical (e.g., prefrontal, motor, and parietal cortices) and subcortical (e.g., pons, thalamus, sub-parabrachial nucleus, periaqueductal gray, and hypothalamus) structures. Psychological/behavioral outputs related to the abovementioned changes are increased comfort, relaxation, pleasantness, vigor and alertness, and reduced symptoms of arousal, anxiety, depression, anger, and confusion. Conclusions: Slow breathing techniques act enhancing autonomic, cerebral and psychological flexibility in a scenario of mutual interactions: we found evidence of links between parasympathetic activity (increased HRV and LF power), CNS activities (increased EEG alpha power and decreased EEG theta power) related to emotional control and psychological well-being in healthy subjects. Our hypothesis considers two different mechanisms for explaining psychophysiological changes induced by voluntary control of slow breathing: one is related to a voluntary regulation of internal bodily states (enteroception), the other is associated to the role of mechanoceptors within the nasal vault in translating slow breathing in a modulation of olfactory bulb activity, which in turn tunes the activity of the entire cortical mantle.
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Affiliation(s)
- Andrea Zaccaro
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy
| | - Andrea Piarulli
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy.,Coma Science Group, GIGA Consciousness, University of Liège, Liège, Belgium
| | - Marco Laurino
- National Research Council, Institute of Clinical Physiology, Pisa, Italy
| | | | - Danilo Menicucci
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy
| | - Bruno Neri
- Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Angelo Gemignani
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy.,National Research Council, Institute of Clinical Physiology, Pisa, Italy.,Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
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20
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Podgurskaya AD, Tsvelaya VA, Frolova SR, Kalita IY, Kudryashova NN, Agladze KI. Effect of heptanol and ethanol on excitation wave propagation in a neonatal rat ventricular myocyte monolayer. Toxicol In Vitro 2018; 51:136-144. [PMID: 29778719 DOI: 10.1016/j.tiv.2018.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 05/11/2018] [Accepted: 05/15/2018] [Indexed: 11/24/2022]
Abstract
In this work, the action of heptanol and ethanol was investigated in a two-dimensional (2D) model of cardiac tissue: the neonatal rat ventricular myocyte monolayer. Heptanol is known in electrophysiology as a gap junction uncoupler but may also inhibit voltage-gated ionic channels. Ethanol is often associated with the occurrence of arrhythmias. These substances influence sodium, calcium, and potassium channels, but the complete mechanism of action of heptanol and ethanol remains unknown. The optical mapping method was used to measure conduction velocities (CVs) in concentrations of 0.05-1.8 mM heptanol and 17-1342 mM ethanol. Heptanol was shown to slow the excitation wave significantly, and a mechanism that involves a simultaneous action on cell coupling and activation threshold was suggested. Whole-cell patch-clamp experiments showed inhibition of sodium and calcium currents at a concentration of 0.5 mM heptanol. Computer modeling was used to estimate the relative contribution of the cell uncoupling and activation threshold increase caused by heptanol. Unlike heptanol, ethanol slightly influenced the CV at clinically relevant concentrations. Additionally, the critical concentrations for re-entry formation in ethanol were determined.
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Affiliation(s)
- A D Podgurskaya
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - V A Tsvelaya
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - S R Frolova
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - I Y Kalita
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - N N Kudryashova
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation; Department of Physics and Astronomy, Ghent University, B-9000 Ghent, Belgium
| | - K I Agladze
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation.
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21
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Biocompatibility Assessment of Conducting PANI/Chitosan Nanofibers for Wound Healing Applications. Polymers (Basel) 2017; 9:polym9120687. [PMID: 30965990 PMCID: PMC6418902 DOI: 10.3390/polym9120687] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/23/2017] [Accepted: 11/24/2017] [Indexed: 12/22/2022] Open
Abstract
As electroactive polymers have recently presented potential in applications in the tissue engineering and biomedical field, this study is aiming at the fabrication of composite nanofibrous membranes containing conducting polyaniline and at the evaluation of their biocompatibility. For that purpose, conducting polyaniline–chitosan (PANI/CS) defect free nanofibres of different ratios (1:3; 3:5 and 1:1) were produced with the electrospinning method. They were characterized as for their morphology, hydrophilicity and electrical conductivity. The membranes were then evaluated for their cellular biocompatibility in terms of cell attachment, morphology and cell proliferation. The effect of the PANI content on the membrane properties is discussed. Increase in PANI content resulted in membranes with higher hydrophobicity and higher electrical conductivity. It was found that none of the membranes showed any toxic effects on osteoblasts and fibroblasts, and that they all supported cell attachment and growth, even to a greater extent than tissue culture plastic. The membrane with the PANI/CS ratio 1:3 supports better cell attachment and proliferation for both cell lines due to a synergistic effect of hydrophilicity retention due to the high chitosan content and the conductivity that PANI introduced to the membrane.
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22
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Adding dimension to cellular mechanotransduction: Advances in biomedical engineering of multiaxial cell-stretch systems and their application to cardiovascular biomechanics and mechano-signaling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017. [DOI: 10.1016/j.pbiomolbio.2017.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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23
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Mitrokhin V, Kazanski V, Kalsin V, Mladenov M, Kamkin A. Interleukin-6 induced activation of a non-selective outward cation conductance in human cardiac fibroblasts. Cytokine 2017. [DOI: 10.1016/j.cyto.2017.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Whyte-Fagundes P, Zoidl G. Mechanisms of pannexin1 channel gating and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:65-71. [PMID: 28735901 DOI: 10.1016/j.bbamem.2017.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 01/07/2023]
Abstract
Pannexins are a family of integral membrane proteins with distinct post-translational modifications, sub-cellular localization and tissue distribution. Panx1 is the most studied and best-characterized isoform of this gene family. The ubiquitous expression, as well as its function as a major ATP release and nucleotide permeation channel, makes Panx1 a primary candidate for participating in the pathophysiology of CNS disorders. While many investigations revolve around Panx1 functions in health and disease, more recently, details started emerging about mechanisms that control Panx1 channel activity. These advancements in Panx1 biology have revealed that beyond its classical role as an unopposed plasma membrane channel, it participates in alternative pathways involving multiple intracellular compartments, protein complexes and a myriad of extracellular participants. Here, we review recent progress in our understanding of Panx1 at the center of these pathways, highlighting its modulation in a context specific manner. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
| | - Georg Zoidl
- Biology, York University, Toronto, Canada; Psychology, York University, Toronto, Canada.
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25
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Thanigaimani S, McLennan E, Linz D, Mahajan R, Agbaedeng TA, Lee G, Kalman JM, Sanders P, Lau DH. Progression and reversibility of stretch induced atrial remodeling: Characterization and clinical implications. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:376-386. [PMID: 28734850 DOI: 10.1016/j.pbiomolbio.2017.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 12/13/2022]
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia and across the developed nations, it contributes to increasing hospitalizations and healthcare burden. Several comorbidities and risk factors including hypertension, heart failure, obstructive sleep apnoea and obesity are known to play an important role in the initiation and perpetuation of AF and atrial stretch or dilatation may play a central mechanistic role. The impact of atrial stretch in the development of AF can vary dependent on the underlying disease. This review focuses on understanding the substrate for AF in conditions of acute and chronic stretch and in the presence of common co-morbidities or risk factors through the review of findings in both animal and human studies. Additionally, the reversibility of atrial remodeling following stretch release will also be discussed. Identification of clinical conditions associated with increased atrial stretch as well as the treatment or prevention of these conditions may help to prevent AF progression and improve sinus rhythm maintenance.
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Affiliation(s)
- Shivshankar Thanigaimani
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Emma McLennan
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Dominik Linz
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Rajiv Mahajan
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Thomas A Agbaedeng
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Geoffrey Lee
- Department of Cardiology, Royal Melbourne Hospital and Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital and Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Dennis H Lau
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia.
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Iaconetti C, Sorrentino S, De Rosa S, Indolfi C. Exosomal miRNAs in Heart Disease. Physiology (Bethesda) 2017; 31:16-24. [PMID: 26661525 DOI: 10.1152/physiol.00029.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Micro-RNAs (miRNAs) are small noncoding RNAs involved in the posttranscriptional regulation of gene expression. Exosomes have recently emerged as novel elements of intercellular communication in the cardiovascular system. Exosomal miRNAs could be key players in intercellular cross-talk, particularly during different diseases such as myocardial infarction (MI) and heart failure (HF). This review addresses the functional role played by exosomal miRNAs in heart disease and their potential use as new biomarkers.
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Affiliation(s)
- Claudio Iaconetti
- Laboratory of Molecular and Cellular Cardiology, Cardiovascular Institute, Magna Graecia University, Catanzaro, Italy; and
| | - Sabato Sorrentino
- Laboratory of Molecular and Cellular Cardiology, Cardiovascular Institute, Magna Graecia University, Catanzaro, Italy; and
| | - Salvatore De Rosa
- Laboratory of Molecular and Cellular Cardiology, Cardiovascular Institute, Magna Graecia University, Catanzaro, Italy; and
| | - Ciro Indolfi
- Laboratory of Molecular and Cellular Cardiology, Cardiovascular Institute, Magna Graecia University, Catanzaro, Italy; and URT-CNR, Magna Graecia University, Catanzaro, Italy
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27
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Civitarese RA, Kapus A, McCulloch CA, Connelly KA. Role of integrins in mediating cardiac fibroblast–cardiomyocyte cross talk: a dynamic relationship in cardiac biology and pathophysiology. Basic Res Cardiol 2016; 112:6. [DOI: 10.1007/s00395-016-0598-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/14/2016] [Indexed: 12/16/2022]
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Effects of Na + Current and Mechanogated Channels in Myofibroblasts on Myocyte Excitability and Repolarization. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:6189374. [PMID: 27980607 PMCID: PMC5131562 DOI: 10.1155/2016/6189374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/09/2016] [Accepted: 10/19/2016] [Indexed: 12/19/2022]
Abstract
Fibrotic remodeling, characterized by fibroblast phenotype switching, is often associated with atrial fibrillation and heart failure. This study aimed to investigate the effects on electrotonic myofibroblast-myocyte (Mfb-M) coupling on cardiac myocytes excitability and repolarization of the voltage-gated sodium channels (VGSCs) and single mechanogated channels (MGCs) in human atrial Mfbs. Mathematical modeling was developed from a combination of (1) models of the human atrial myocyte (including the stretch activated ion channel current, ISAC) and Mfb and (2) our formulation of currents through VGSCs (INa_Mfb) and MGCs (IMGC_Mfb) based upon experimental findings. The effects of changes in the intercellular coupling conductance, the number of coupled Mfbs, and the basic cycle length on the myocyte action potential were simulated. The results demonstrated that the integration of ISAC, INa_Mfb, and IMGC_Mfb reduced the amplitude of the myocyte membrane potential (Vmax) and the action potential duration (APD), increased the depolarization of the resting myocyte membrane potential (Vrest), and made it easy to trigger spontaneous excitement in myocytes. For Mfbs, significant electrotonic depolarizations were exhibited with the addition of INa_Mfb and IMGC_Mfb. Our results indicated that ISAC, INa_Mfb, and IMGC_Mfb significantly influenced myocytes and Mfbs properties and should be considered in future cardiac pathological mathematical modeling.
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Pellman J, Zhang J, Sheikh F. Myocyte-fibroblast communication in cardiac fibrosis and arrhythmias: Mechanisms and model systems. J Mol Cell Cardiol 2016; 94:22-31. [PMID: 26996756 DOI: 10.1016/j.yjmcc.2016.03.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/27/2016] [Accepted: 03/14/2016] [Indexed: 12/17/2022]
Abstract
Development of cardiac fibrosis and arrhythmias is controlled by the activity of and communication between cardiomyocytes and fibroblasts in the heart. Myocyte-fibroblast interactions occur via both direct and indirect means including paracrine mediators, extracellular matrix interactions, electrical modulators, mechanical junctions, and membrane nanotubes. In the diseased heart, cardiomyocyte and fibroblast ratios and activity, and thus myocyte-fibroblast interactions, change and are thought to contribute to the course of disease including development of fibrosis and arrhythmogenic activity. Fibroblasts have a developing role in modulating cardiomyocyte electrical and hypertrophic activity, however gaps in knowledge regarding these interactions still exist. Research in this field has necessitated the development of unique approaches to isolate and control myocyte-fibroblast interactions. Numerous methods for 2D and 3D co-culture systems have been developed, while a growing part of this field is in the use of better tools for in vivo systems including cardiomyocyte and fibroblast specific Cre mouse lines for cell type specific genetic ablation. This review will focus on (i) mechanisms of myocyte-fibroblast communication and their effects on disease features such as cardiac fibrosis and arrhythmias as well as (ii) methods being used and currently developed in this field.
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Affiliation(s)
- Jason Pellman
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jing Zhang
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Farah Sheikh
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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Zhang W, St Clair D, Butterfield A, Vore M. Loss of Mrp1 Potentiates Doxorubicin-Induced Cytotoxicity in Neonatal Mouse Cardiomyocytes and Cardiac Fibroblasts. Toxicol Sci 2016; 151:44-56. [PMID: 26822305 DOI: 10.1093/toxsci/kfw021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Doxorubicin (DOX) induces dose-dependent cardiotoxicity in part due to its ability to induce oxidative stress. We showed that loss of multidrug resistance-associated protein 1 (Abcc1/Mrp1) potentiates DOX-induced cardiac dysfunction in mice in vivo Here, we characterized DOX toxicity in cultured cardiomyocytes (CM) and cardiac fibroblasts (CF) derived from C57BL wild type (WT) and Mrp1 null (Mrp1-/-) neonatal mice. CM accumulated more intracellular DOX relative to CF but this accumulation did not differ between genotypes. Following DOX (0.3-4 μM), Mrp1-/- CM, and CF, especially CM, showed a greater decrease in viability and increased apoptosis and DNA damage, demonstrated by higher caspase 3 cleavage, poly (ADP-ribose) polymerase 1 (PARP) cleavage and phosphorylated histone H2AX (γH2AX) levels versus WT cells. Saline- and DOX-treated Mrp1-/- cells had significantly higher intracellular GSH and GSSG compared with WT cells (P < .05), but the redox potential (Eh) of the GSH/GSSG pool did not differ between genotypes in CM and CF, indicating that Mrp1-/- cells maintain this major redox couple. DOX increased expression of the rate-limiting GSH synthesis enzyme glutamate-cysteine ligase catalytic (GCLc) and regulatory subunits (GCLm) to a significantly greater extent in Mrp1-/- versus WT cells, suggesting adaptive responses to oxidative stress in Mrp1-/- cells that were inadequate to afford protection. Expression of extracellular superoxide dismutase (ECSOD/SOD3) was lower (P < .05) in Mrp1-/- versus WT CM treated with saline (62% ± 8% of WT) or DOX (43% ± 12% of WT). Thus, Mrp1 protects CM in particular and CF against DOX-induced toxicity, potentially by regulating extracellular redox states.
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Affiliation(s)
- Wei Zhang
- *Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Daret St Clair
- *Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506
| | - Mary Vore
- *Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536;
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Mahoney VM, Mezzano V, Morley GE. A review of the literature on cardiac electrical activity between fibroblasts and myocytes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:128-33. [PMID: 26713556 DOI: 10.1016/j.pbiomolbio.2015.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/12/2015] [Accepted: 12/16/2015] [Indexed: 12/13/2022]
Abstract
Myocardial injuries often lead to fibrotic deposition. This review presents evidence supporting the concept that fibroblasts in the heart electrically couple to myocytes.
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Affiliation(s)
- Vanessa M Mahoney
- Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Valeria Mezzano
- Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Gregory E Morley
- Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA.
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Fountoulaki K, Dagres N, Iliodromitis EK. Cellular Communications in the Heart. Card Fail Rev 2015; 1:64-68. [PMID: 28785434 PMCID: PMC5490974 DOI: 10.15420/cfr.2015.1.2.64] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/12/2015] [Indexed: 11/04/2022] Open
Abstract
Heart failure is one of the leading causes of morbidity and mortality worldwide. Cardiac remodelling is first an adaptive, becoming a maladaptive, compensatory mechanism that finally causes ventricular dysfunction independently of the etiology of the initial insult. In the present article the authors describe the elements of the human heart, examining their basic functions and their inter-communication under both normal and pathological circumstances. Cardiac myocytes carry out mechanical and electrical functions of the heart and cardiac fibroblasts maintain its structural integrity. Several factors can affect fibroblast activation and under pathological stress they transdifferentiate into myofibroblasts. Endothelial cells have complex biological functions, including the control of vascular permeability, vasomotion, regulation of haemostasis, immune responses and angiogenesis. The extracellular matrix is a complex architectural network consisting of a variety of proteins. Various routes using a plethora of products and mediators contribute to the cross-talk of the myocytes with endothelial cells, extracellular matrix and cardiac fibroblasts. A better understanding of the entire mechanism of cellular communication by the established or the more recently discovered agents will certainly emerge promising new perspectives when looking at the prevention of heart failure and leading to more substantial therapeutic interventions.
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Affiliation(s)
- Katerina Fountoulaki
- Cardiothoracic Intensive Care Unit, Onassis Cardiac Surgery Centre, Athens, Greece
| | - Nikolaos Dagres
- Second University Department of Cardiology, Attikon General Hospial, University of Athens, Athens, Greece
| | - Efstathios K Iliodromitis
- Second University Department of Cardiology, Attikon General Hospial, University of Athens, Athens, Greece
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Fleischman A, Vecchio C, Sunny Y, Bawiec CR, Lewin PA, Kresh JY, Kohut AR. Ultrasound-induced modulation of cardiac rhythm in neonatal rat ventricular cardiomyocytes. J Appl Physiol (1985) 2015; 118:1423-8. [PMID: 25858493 DOI: 10.1152/japplphysiol.00980.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 04/02/2015] [Indexed: 11/22/2022] Open
Abstract
Isolated neonatal rat ventricular cardiomyocytes were used to study the influence of ultrasound on the chronotropic response in a tissue culture model. The beat frequency of the cells, varying from 40 to 90 beats/min, was measured based upon the translocation of the nuclear membrane captured by a high-speed camera. Ultrasound pulses (frequency = 2.5 MHz) were delivered at 300-ms intervals [3.33 Hz pulse repetition frequency (PRF)], in turn corresponding to 200 pulses/min. The intensity of acoustic energy and pulse duration were made variable, 0.02-0.87 W/cm(2) and 1-5 ms, respectively. In 57 of 99 trials, there was a noted average increase in beat frequency of 25% with 8-s exposures to ultrasonic pulses. Applied ultrasound energy with a spatial peak time average acoustic intensity (Ispta) of 0.02 W/cm(2) and pulse duration of 1 ms effectively increased the contraction rate of cardiomyocytes (P < 0.05). Of the acoustic power tested, the lowest level of acoustic intensity and shortest pulse duration proved most effective at increasing the electrophysiological responsiveness and beat frequency of cardiomyocytes. Determining the optimal conditions for delivery of ultrasound will be essential to developing new models for understanding mechanoelectrical coupling (MEC) and understanding novel nonelectrical pacing modalities for clinical applications.
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Affiliation(s)
| | - Christopher Vecchio
- School of Biomedical Engineering, Science & Health System, Drexel University, Philadelphia, Pennsylvania; and
| | - Youhan Sunny
- School of Biomedical Engineering, Science & Health System, Drexel University, Philadelphia, Pennsylvania; and
| | - Christopher R Bawiec
- School of Biomedical Engineering, Science & Health System, Drexel University, Philadelphia, Pennsylvania; and
| | - Peter A Lewin
- School of Biomedical Engineering, Science & Health System, Drexel University, Philadelphia, Pennsylvania; and
| | - J Yasha Kresh
- Department of Medicine, School of Medicine and School of Biomedical Engineering, Science & Health System, Drexel University, Philadelphia, Pennsylvania; and Department of Cardiothoracic Surgery, School of Medicine School of Medicine and Drexel University, Philadelphia, Pennsylvania
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34
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Dostal D, Glaser S, Baudino TA. Cardiac Fibroblast Physiology and Pathology. Compr Physiol 2015; 5:887-909. [DOI: 10.1002/cphy.c140053] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Wu CT, Qi XY, Huang H, Naud P, Dawson K, Yeh YH, Harada M, Kuo CT, Nattel S. Disease and region-related cardiac fibroblast potassium current variations and potential functional significance. Cardiovasc Res 2014; 102:487-96. [PMID: 24596399 DOI: 10.1093/cvr/cvu055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIMS Fibroblasts, which play an important role in cardiac function/dysfunction, including arrhythmogenesis, have voltage-dependent (Kv) currents of unknown importance. Here, we assessed the differential expression of Kv currents between atrial and ventricular fibroblasts from control dogs and dogs with an atrial arrhythmogenic substrate caused by congestive heart failure (CHF). METHODS AND RESULTS Left atrial (LA) and ventricular (LV) fibroblasts were freshly isolated from control and CHF dogs (2-week ventricular tachypacing, 240 bpm). Kv currents were measured with whole-cell voltage-clamp, mRNA by quantitative polymerase chain reaction (qPCR) and fibroblast proliferation by (3)H-thymidine incorporation. Robust voltage-dependent tetraethylammonium (TEA)-sensitive K(+) currents (IC50 ∼1 mM) were recorded. The morphologies and TEA responses of LA and LV fibroblast Kv currents were similar. LV fibroblast Kv-current densities were significantly greater than LA, and Kv-current densities were significantly less in CHF than control. The mRNA expression of Kv-channel subunits Kv1.5 and Kv4.3 was less in LA vs. LV fibroblasts and was down-regulated in CHF, consistent with K(+)-current recordings. Ca(2+)-dependent K(+)-channel subunit (KCa1.1) mRNA and currents were less expressed in LV vs. LA fibroblasts. Inhibiting LA fibroblast K(+) current with 1 mmol/L of TEA or KCa1.1 current with paxilline increased proliferation. CONCLUSIONS Fibroblast Kv-current expression is smaller in CHF vs. control, as well as LA vs. LV. KCa1.1 current is greater in LA vs. LV. Suppressing Kv current with TEA enhances fibroblast proliferation, suggesting that Kv current might act to check fibroblast proliferation and that reduced Kv current in CHF may contribute to fibrosis. Fibroblast Kv-current remodelling may play a role in the atrial fibrillation (AF) substrate; modulating fibroblast K(+) channels may present a novel strategy to prevent fibrosis and AF.
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Affiliation(s)
- Chia-Tung Wu
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8 Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China
| | - Xiao-Yan Qi
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8
| | - Hai Huang
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8
| | - Patrice Naud
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8
| | - Kristin Dawson
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Yung-Hsin Yeh
- Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China
| | - Masahide Harada
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8 Department of Cardiology, Hamamatsu Medical Center, Hamamatsu, Japan
| | - Chi-Tai Kuo
- Chang-Gung Memorial Hospital and University, Taoyuan, Taiwan, Republic of China
| | - Stanley Nattel
- Research Center, Montreal Heart Institute, Université de Montréal, 5000 Belanger St. E., Montreal, QC, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
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Kohl P, Gourdie RG. Fibroblast-myocyte electrotonic coupling: does it occur in native cardiac tissue? J Mol Cell Cardiol 2014; 70:37-46. [PMID: 24412581 PMCID: PMC4001130 DOI: 10.1016/j.yjmcc.2013.12.024] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/29/2013] [Accepted: 12/30/2013] [Indexed: 11/05/2022]
Abstract
Heterocellular electrotonic coupling between cardiac myocytes and non-excitable connective tissue cells has been a long-established and well-researched fact in vitro. Whether or not such coupling exists in vivo has been a matter of considerable debate. This paper reviews the development of experimental insight and conceptual views on this topic, describes evidence in favour of and against the presence of such coupling in native myocardium, and identifies directions for further study needed to resolve the riddle, perhaps less so in terms of principal presence which has been demonstrated, but undoubtedly in terms of extent, regulation, patho-physiological context, and actual relevance of cardiac myocyte–non-myocyte coupling in vivo. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium." Electrical coupling of cardiomyocytes and fibroblasts is well-established in vitro Whether such hetero-cellular coupling exists in vivo has been a matter of debate We review the development of experimental and conceptual insight into the topic Conclusion 1: hetero-cellular coupling in heart tissue has been shown in principle Conclusion 2: extent, regulation, context, and relevance remain to be established
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Affiliation(s)
- Peter Kohl
- Imperial College, National Heart and Lung Institute, Harefield Hospital, UB6 9JH, UK.
| | - Robert G Gourdie
- Virginia Tech, Carilion Research Institute, 2 Riverside Circle, Roanoke, VA 24015, USA
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Howard CM, Baudino TA. Dynamic cell-cell and cell-ECM interactions in the heart. J Mol Cell Cardiol 2013; 70:19-26. [PMID: 24140801 DOI: 10.1016/j.yjmcc.2013.10.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/07/2013] [Accepted: 10/09/2013] [Indexed: 12/17/2022]
Abstract
Recent studies have placed an increasing amount of emphasis on the cardiovascular system and understanding how the heart and its vasculature can be regenerated following pathological stresses, such as hypertension and myocardial infarction. The remodeling process involves the permanent cellular constituents of the heart including myocytes, fibroblasts, endothelial cells, pericytes, smooth muscle cells and stem cells. It also includes transient cell populations, such as immune cells (e.g. lymphocytes, mast cells and macrophages) and circulating stem cells. Following injury, there are dramatic shifts in the various cardiac cell populations that can affect cell-cell and cell-extracellular matrix interactions and cardiac function. Cardiac fibroblasts are a key component in normal heart function, as well as during the remodeling process through dynamic cell-cell interactions and synthesis and degradation of the extracellular matrix. Fibroblasts dynamically interact with the various cardiac cell populations through mechanical, chemical (autocrine and/or paracrine) and electrophysiological means to alter gene and protein expression, cellular processes and ultimately cardiac function. Better understanding these cell-cell and cell-extracellular matrix interactions and their biological consequences should provide novel therapeutic targets for the treatment of heart disease. In this review we discuss the nature of these interactions and the importance of these interactions in maintaining normal heart function, as well as their role in the cardiac remodeling process. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium."
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Affiliation(s)
| | - Troy A Baudino
- Department of Medicine, Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M Health Science Center, Temple, TX 76504, USA; Central Texas Veterans Health Care System, Temple, TX 76504, USA.
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Nayak AR, Shajahan TK, Panfilov AV, Pandit R. Spiral-wave dynamics in a mathematical model of human ventricular tissue with myocytes and fibroblasts. PLoS One 2013; 8:e72950. [PMID: 24023798 PMCID: PMC3762734 DOI: 10.1371/journal.pone.0072950] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 07/15/2013] [Indexed: 11/18/2022] Open
Abstract
Cardiac fibroblasts, when coupled functionally with myocytes, can modulate the electrophysiological properties of cardiac tissue. We present systematic numerical studies of such modulation of electrophysiological properties in mathematical models for (a) single myocyte-fibroblast (MF) units and (b) two-dimensional (2D) arrays of such units; our models build on earlier ones and allow for zero-, one-, and two-sided MF couplings. Our studies of MF units elucidate the dependence of the action-potential (AP) morphology on parameters such as , the fibroblast resting-membrane potential, the fibroblast conductance , and the MF gap-junctional coupling . Furthermore, we find that our MF composite can show autorhythmic and oscillatory behaviors in addition to an excitable response. Our 2D studies use (a) both homogeneous and inhomogeneous distributions of fibroblasts, (b) various ranges for parameters such as , and , and (c) intercellular couplings that can be zero-sided, one-sided, and two-sided connections of fibroblasts with myocytes. We show, in particular, that the plane-wave conduction velocity decreases as a function of , for zero-sided and one-sided couplings; however, for two-sided coupling, decreases initially and then increases as a function of , and, eventually, we observe that conduction failure occurs for low values of . In our homogeneous studies, we find that the rotation speed and stability of a spiral wave can be controlled either by controlling or . Our studies with fibroblast inhomogeneities show that a spiral wave can get anchored to a local fibroblast inhomogeneity. We also study the efficacy of a low-amplitude control scheme, which has been suggested for the control of spiral-wave turbulence in mathematical models for cardiac tissue, in our MF model both with and without heterogeneities.
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Affiliation(s)
- Alok Ranjan Nayak
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
| | - T. K. Shajahan
- Centre for Nonlinear Dynamics in Physiology and Medicine, McGill University, Montreal, Canada
| | - A. V. Panfilov
- Department of Physics and Astronomy, Gent University, Gent, Belgium
| | - Rahul Pandit
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- * E-mail:
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Li C, Qu X, Xu W, Qu N, Mei L, Liu Y, Wang X, Yu X, Liu Z, Nie D, Liu Y, Yan J, Yang B, Lu Y, Chu W. Arsenic trioxide induces cardiac fibroblast apoptosis in vitro and in vivo by up-regulating TGF-β1 expression. Toxicol Lett 2013; 219:223-30. [PMID: 23542815 DOI: 10.1016/j.toxlet.2013.03.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 02/03/2023]
Abstract
Arsenic trioxide (As2O3; ATO) is clinically effective in treating acute promyelocytic leukemia (APL); however, it frequently causes cardiotoxic effects. This study was designed to investigate whether ATO could induce apoptosis of cardiac fibroblasts (CFs) that play very important roles in maintaining the structure integrity and function of the heart. Cardiac fibroblasts from guinea pigs administered with ATO (1mg/kgbw) were used to test the pro-apoptotic role of ATO in vivo. The current study demonstrated that ATO induced morphological characteristics of apoptosis and Caspase-3 activation in CFs of guinea pigs along with a significant up-regulation in TGF-β1 protein expression, Bax/Bcl-2 ratio and ERK1/2 phosphorylation. In vitro MTT assay showed that ATO remarkably reduced the viability of cultured cardiac fibroblasts (NRCFs) from neonatal rat in a concentration- and time-dependent manner. Consistent with the notions in vivo, ATO significantly induced the apoptosis in NRCFs, dramatically up-regulated TGF-β1 protein level and Bax/Bcl-2 ratio in a time-dependent fashion and activated Caspase-3 and ERK1/2. Finally, pretreatment with LY364947, an inhibitor of TGF-β signaling could apparently reverse these changes. We therefore conclude that TGF-β is functionally linked to ERK1/2 and that TGF-β signaling is responsible for ATO-induced CFs apoptosis, which provides a novel mechanism of ATO related cardiac toxicology.
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Affiliation(s)
- Cui Li
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang 150081, China
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40
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Benamer N, Vasquez C, Mahoney VM, Steinhardt MJ, Coetzee WA, Morley GE. Fibroblast KATP currents modulate myocyte electrophysiology in infarcted hearts. Am J Physiol Heart Circ Physiol 2013; 304:H1231-9. [PMID: 23436329 DOI: 10.1152/ajpheart.00878.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac metabolism remains altered for an extended period of time after myocardial infarction. Studies have shown fibroblasts from normal hearts express KATP channels in culture. It is unknown whether fibroblasts from infarcted hearts express KATP channels and whether these channels contribute to scar and border zone electrophysiology. KATP channel subunit expression levels were determined in fibroblasts isolated from normal hearts (Fb), and scar (sMI-Fb) and remote (rMI-Fb) regions of left anterior descending coronary artery (LAD) ligated rat hearts. Whole cell KATP current density was determined with patch clamp. Action potential duration (APD) was measured with optical mapping in myocyte-only cultures and heterocellular cultures with fibroblasts with and without 100 μmol/l pinacidil. Whole heart optical mapping was used to assess KATP channel activity following LAD ligation. Pinacidil activated a potassium current (35.4 ± 7.5 pA/pF at 50 mV) in sMI-Fb that was inhibited with 10 μmol/l glibenclamide. Kir6.2 and SUR2 transcript levels were elevated in sMI-Fb. Treatment with Kir6.2 short interfering RNA decreased KATP currents (87%) in sMI-Fb. Treatment with pinacidil decreased APD (26%) in co-cultures with sMI-Fb. APD values were prolonged in LAD ligated hearts after perfusion with glibenclamide. KATP channels are present in fibroblasts from the scar and border zones of infarcted hearts. Activation of fibroblast KATP channels could modulate the electrophysiological substrate beyond the acute ischemic event. Targeting fibroblast KATP channels could represent a novel therapeutic approach to modify border zone electrophysiology after cardiac injury.
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Affiliation(s)
- Najate Benamer
- Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York 10016, USA
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41
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Atrial remodeling in varying clinical substrates within beating human hearts: Relevance to atrial fibrillation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:278-94. [DOI: 10.1016/j.pbiomolbio.2012.07.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 07/24/2012] [Indexed: 11/19/2022]
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42
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Chu W, Li C, Qu X, Zhao D, Wang X, Yu X, Cai F, Liang H, Zhang Y, Zhao X, Li B, Qiao G, Dong D, Lu Y, Du Z, Yang B. Arsenic-induced interstitial myocardial fibrosis reveals a new insight into drug-induced long QT syndrome. Cardiovasc Res 2012; 96:90-8. [PMID: 22853924 DOI: 10.1093/cvr/cvs230] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
AIMS Arsenic trioxide (ATO), an effective therapeutic agent for acute promyelocytic leukaemia, can cause sudden cardiac death due to long QT syndrome (LQTS). The present study was designed to determine whether ATO could induce cardiac fibrosis and explore whether cardiac fibroblasts (CFs) are involved in the development of LQTS by ATO. METHODS AND RESULTS ATO treatment of guinea pigs caused substantial interstitial myocardial fibrosis and LQTS, which was accompanied by an increase in transforming growth factor β1(TGF-β1) secretion and a decrease in ether-à-go-go-related gene (HERG) and inward rectifying potassium channel (I(K1)) subunit Kir2.1 protein levels. ATO promoted collagen production and TGF-β1 expression and secretion in cultured CFs. Whole-cell patch clamp and western blotting showed that treatment with TGF-β1 markedly reduced HERG and I(K1) current densities and downregulated HERG and Kir2.1 protein expression in HEK293 cells stably transfected with the human recombinant HERG channel and in cardiomyocytes (CMs). These changes were completely reversed by treatment with the protein kinase A (PKA) antagonist, H89. CM and CF co-cultures showed that ATO significantly increased TGF-β1 levels in the culture medium, whereas markedly reduced HERG and Kir2.1 protein levels were observed in CMs compared with ATO-treated CMs not co-cultured with CFs. Finally, in vivo administration of LY364947, a pharmacological antagonist of TGF-β signalling, dramatically prevented interstitial fibrosis and LQTS and abolished aberrant expression of TGF-β1, HERG, and Kir2.1 in ATO-treated guinea pigs. CONCLUSION ATO-induced TGF-β1 secretion from CFs aggravates QT prolongation, suggesting that modulation of TGF-β signalling may provide a novel strategy for the treatment of drug-induced LQTS.
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Affiliation(s)
- Wenfeng Chu
- Department of Pharmacology, Harbin Medical University, Xuefu Road 194, Harbin, Heilongjiang 150081, PR China
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43
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Dabiri BE, Lee H, Parker KK. A potential role for integrin signaling in mechanoelectrical feedback. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:196-203. [PMID: 22819851 DOI: 10.1016/j.pbiomolbio.2012.07.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 07/11/2012] [Indexed: 01/20/2023]
Abstract
Certain forms of heart disease involve gross morphological changes to the myocardium that alter its hemodynamic loading conditions. These changes can ultimately lead to the increased deposition of extracellular matrix (ECM) proteins, such as collagen and fibronectin, which together work to pathologically alter the myocardium's bulk tissue mechanics. In addition to changing the mechanical properties of the heart, this maladaptive remodeling gives rise to changes in myocardium electrical conductivity and synchrony since the tissue's mechanical properties are intimately tied to its electrical characteristics. This phenomenon, called mechanoelectrical coupling (MEC), can render individuals affected by heart disease arrhythmogenic and susceptible to Sudden Cardiac Death (SCD). The underlying mechanisms of MEC have been attributed to various processes, including the action of stretch activated channels and changes in troponin C-Ca(2+) binding affinity. However, changes in the heart post infarction or due to congenital myopathies are also accompanied by shifts in the expression of various molecular components of cardiomyocytes, including the mechanosensitive family of integrin proteins. As transmembrane proteins, integrins mechanically couple the ECM with the intracellular cytoskeleton and have been implicated in mediating ion homeostasis in various cell types, including neurons and smooth muscle. Given evidence of altered integrin expression in the setting of heart disease coupled with the associated increased risk for arrhythmia, we argue in this review that integrin signaling contributes to MEC. In light of the significant mortality associated with arrhythmia and SCD, close examination of all culpable mechanisms, including integrin-mediated MEC, is necessary.
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Affiliation(s)
- Borna E Dabiri
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, 29 Oxford St, Pierce Hall 321, Cambridge, MA 02138, USA
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44
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Nguyen TP, Xie Y, Garfinkel A, Qu Z, Weiss JN. Arrhythmogenic consequences of myofibroblast-myocyte coupling. Cardiovasc Res 2011; 93:242-51. [PMID: 22049532 DOI: 10.1093/cvr/cvr292] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
AIMS Fibrosis is known to promote cardiac arrhythmias by disrupting myocardial structure. Given recent evidence that myofibroblasts form gap junctions with myocytes at least in co-cultures, we investigated whether myofibroblast-myocyte coupling can promote arrhythmia triggers, such as early afterdepolarizations (EADs), by directly influencing myocyte electrophysiology. METHODS AND RESULTS Using the dynamic voltage clamp technique, patch-clamped adult rabbit ventricular myocytes were electrotonically coupled to one or multiple virtual fibroblasts or myofibroblasts programmed with eight combinations of capacitance, membrane resistance, resting membrane potential, and gap junction coupling resistance, spanning physiologically realistic ranges. Myocytes were exposed to oxidative (1 mmol/L H(2)O(2)) or ionic (2.7 mmol/L hypokalaemia) stress to induce bradycardia-dependent EADs. In the absence of myofibroblast-myocyte coupling, EADs developed during slow pacing (6 s), but were completely suppressed by faster pacing (1 s). However, in the presence of myofibroblast-myocyte coupling, EADs could no longer be suppressed by rapid pacing, especially when myofibroblast resting membrane potential was depolarized (-25 mV). Analysis of the myofibroblast-myocyte virtual gap junction currents revealed two components: an early transient-outward I(to)-like current and a late sustained current. Selective elimination of the I(to)-like component prevented EADs, whereas selective elimination of the late component did not. CONCLUSION Coupling of myocytes to myofibroblasts promotes EAD formation as a result of a mismatch in early vs. late repolarization reserve caused by the I(to)-like component of the gap junction current. These cellular and ionic mechanisms may contribute to the pro-arrhythmic risk in fibrotic hearts.
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Affiliation(s)
- Thao P Nguyen
- UCLA Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, Los Angeles, CA, USA
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45
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Miragoli M, Sheikh Abdul Kadir SH, Sheppard MN, Salvarani N, Virta M, Wells S, Lab MJ, Nikolaev VO, Moshkov A, Hague WM, Rohr S, Williamson C, Gorelik J. A protective antiarrhythmic role of ursodeoxycholic acid in an in vitro rat model of the cholestatic fetal heart. Hepatology 2011; 54:1282-92. [PMID: 21809354 PMCID: PMC4900448 DOI: 10.1002/hep.24492] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 06/02/2011] [Indexed: 12/27/2022]
Abstract
UNLABELLED Intrahepatic cholestasis of pregnancy may be complicated by fetal arrhythmia, fetal hypoxia, preterm labor, and, in severe cases, intrauterine death. The precise etiology of fetal death is not known. However, taurocholate has been demonstrated to cause arrhythmia and abnormal calcium dynamics in cardiomyocytes. To identify the underlying reason for increased susceptibility of fetal cardiomyocytes to arrhythmia, we studied myofibroblasts (MFBs), which appear during structural remodeling of the adult diseased heart. In vitro, they depolarize rat cardiomyocytes via heterocellular gap junctional coupling. Recently, it has been hypothesized that ventricular MFBs might appear in the developing human heart, triggered by physiological fetal hypoxia. However, their presence in the fetal heart (FH) and their proarrhythmogenic effects have not been systematically characterized. Immunohistochemistry demonstrated that ventricular MFBs transiently appear in the human FH during gestation. We established two in vitro models of the maternal heart (MH) and FH, both exposed to increasing doses of taurocholate. The MH model consisted of confluent strands of rat cardiomyocytes, whereas for the FH model, we added cardiac MFBs on top of cardiomyocytes. Taurocholate in the FH model, but not in the MH model, slowed conduction velocity from 19 to 9 cm/s, induced early after depolarizations, and resulted in sustained re-entrant arrhythmias. These arrhythmic events were prevented by ursodeoxycholic acid, which hyperpolarized MFB membrane potential by modulating potassium conductance. CONCLUSION These results illustrate that the appearance of MFBs in the FH may contribute to arrhythmias. The above-described mechanism represents a new therapeutic approach for cardiac arrhythmias at the level of MFB.
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Affiliation(s)
- Michele Miragoli
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK
| | | | - Mary N. Sheppard
- Dept. of Histopathology, Royal Brompton Hospital, Sydney Street London SW3 6NP
| | - Nicolό Salvarani
- Dept. of Physiology, University of Bern, Bühlplatz 5, 3012 Bern, CH
| | - Matilda Virta
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK
| | - Sarah Wells
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK
| | - Max J. Lab
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK
| | | | - Alexey Moshkov
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK
| | - William M Hague
- Dept of Obstetrics, University of Adelaide, Women’s and Children’s Hospital, North Adelaide, South Australia 5006, Australia
| | - Stephan Rohr
- Dept. of Physiology, University of Bern, Bühlplatz 5, 3012 Bern, CH
| | - Catherine Williamson
- Institute of Reproductive and Developmental Biology, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Julia Gorelik
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK
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Atrial fibrillation and heart failure parallels: lessons for atrial fibrillation prevention. Crit Pathw Cardiol 2011; 10:46-51. [PMID: 21562376 DOI: 10.1097/hpc.0b013e31820e1a4b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Heart failure (HF) and atrial fibrillation (AF) are 2 of the most common cardiovascular diseases encountered in clinical practice, and the prevalence of these diseases continues to grow worldwide with the aging of the global population. While recognizing that AF is a heterogeneous disorder, we submit that the parallels between AF and HF may arise because many cases of AF and HF result from the cumulative exposure of the atria and ventricles to a common set of systemic cardiovascular risk factors. Over time, exposure to risk factors promotes development of atrial and ventricular structural and functional abnormalities through activation of several biologic pathways in concert: upregulation of neurohormonal signaling cascades, release of inflammatory mediators, programmed cell death, and fibrosis. Cardiac structural remodeling occurs in concert with electrophysiologic remodeling, both of which contribute to atrial and ventricular rhythm disturbances, including AF. AF and HF, instead of representing distinct disease processes, often represent different endpoints along a disease continuum. By reviewing some of the mechanistic parallels between AF and HF, we hope to emphasize the connection between established cardiovascular risk factors, cardiac remodeling and AF, with a view to promote strategies for AF prevention.
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Badylak SF, Taylor D, Uygun K. Whole-organ tissue engineering: decellularization and recellularization of three-dimensional matrix scaffolds. Annu Rev Biomed Eng 2011; 13:27-53. [PMID: 21417722 PMCID: PMC10887492 DOI: 10.1146/annurev-bioeng-071910-124743] [Citation(s) in RCA: 679] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The definitive treatment for end-stage organ failure is orthotopic transplantation. However, the demand for transplantation far exceeds the number of available donor organs. A promising tissue-engineering/regenerative-medicine approach for functional organ replacement has emerged in recent years. Decellularization of donor organs such as heart, liver, and lung can provide an acellular, naturally occurring three-dimensional biologic scaffold material that can then be seeded with selected cell populations. Preliminary studies in animal models have provided encouraging results for the proof of concept. However, significant challenges for three-dimensional organ engineering approach remain. This manuscript describes the fundamental concepts of whole-organ engineering, including characterization of the extracellular matrix as a scaffold, methods for decellularization of vascular organs, potential cells to reseed such a scaffold, techniques for the recellularization process and important aspects regarding bioreactor design to support this approach. Critical challenges and future directions are also discussed.
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Affiliation(s)
- Stephen F Badylak
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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48
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Chiang WY, Lai PY, Chan CK. Frequency enhancement in coupled noisy excitable elements. PHYSICAL REVIEW LETTERS 2011; 106:254102. [PMID: 21770642 DOI: 10.1103/physrevlett.106.254102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Indexed: 05/31/2023]
Abstract
Oscillatory dynamics of coupled excitable FitzHugh-Nagumo elements in the presence of noise is investigated as a function of the coupling strength g. For two such coupled elements, their frequencies are enhanced and will synchronize at a frequency higher than the uncoupled frequencies of each element. As g increases, there is an unexpected peak in the frequency enhancement before reaching synchronization. The results can be understood with an analytic model based on the excitation across a potential barrier whose height is controlled by g. Simulation results of a coupled square lattice can quantitatively reproduce the unexpected peak in the variation of the beating rates observed in cultured cardiac cells experiments.
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Affiliation(s)
- Wei-Yin Chiang
- Department of Physics, Graduate Institute of Biophysics, and Center for Complex Systems, National Central University, Chungli, Taiwan 320, Republic of China
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Tandon N, Marsano A, Maidhof R, Wan L, Park H, Vunjak-Novakovic G. Optimization of electrical stimulation parameters for cardiac tissue engineering. J Tissue Eng Regen Med 2011; 5:e115-25. [PMID: 21604379 DOI: 10.1002/term.377] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 09/02/2010] [Indexed: 02/01/2023]
Abstract
In vitro application of pulsatile electrical stimulation to neonatal rat cardiomyocytes cultured on polymer scaffolds has been shown to improve the functional assembly of cells into contractile engineered cardiac tissues. However, to date, the conditions of electrical stimulation have not been optimized. We have systematically varied the electrode material, amplitude and frequency of stimulation to determine the conditions that are optimal for cardiac tissue engineering. Carbon electrodes, exhibiting the highest charge-injection capacity and producing cardiac tissues with the best structural and contractile properties, were thus used in tissue engineering studies. Engineered cardiac tissues stimulated at 3 V/cm amplitude and 3 Hz frequency had the highest tissue density, the highest concentrations of cardiac troponin-I and connexin-43 and the best-developed contractile behaviour. These findings contribute to defining bioreactor design specifications and electrical stimulation regime for cardiac tissue engineering.
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Affiliation(s)
- Nina Tandon
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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50
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Kamkin A, Kirischuk S, Kiseleva I. Single mechano-gated channels activated by mechanical deformation of acutely isolated cardiac fibroblasts from rats. Acta Physiol (Oxf) 2010; 199:277-92. [PMID: 20102342 DOI: 10.1111/j.1748-1716.2010.02086.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM Mechanosensitive conductances were reported in cardiac fibroblasts, but the properties of single channels mediating their mechanosensitivity remain uncharacterized. The aim of this work was to investigate single mechano-gated channels (MGCs) activated by mechanical deformations of cardiac fibroblasts. METHODS Currents through single MGCs and mechanosensitive whole-cell currents were recorded from isolated rat atrial fibroblasts using the cell-attached and whole-cell patch-clamp configurations respectively. Defined mechanical stress was applied via the patch pipette used for the whole-cell recordings. RESULTS Under resting conditions occasional short openings of two types of single MGCs with conductances of 43 and 87 pS were observed. Both types of channels displayed a linear current-voltage relationship with the reversal potential around 0 mV. Small (1 microm) mechanical deformations affected neither single nor whole-cell mechano-gated currents. Cell compressions (2, 3 and 4 microm) augmented the whole-cell currents and increased the frequency and duration of single channel openings. Cell stretches (2, 3 and 4 microm) inactivated the whole-cell currents and abolished the activity of single MGCs. Gd(3+) (8 microm) blocked the whole-cell currents within 5 min. No single channel activity was observed in the cell-attached mode when Gd(3+) was added to the intrapipette solution. Cytochalasin D and colchicine (100 microm each) completely blocked both the whole-cell and single channel currents. CONCLUSIONS These findings show that rat atrial fibroblasts express two types of MGCs whose activity is governed by cell deformation. We conclude that fibroblasts can sense the direction of applied stress and contribute to mechano-electrical coupling in the heart.
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