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Pásek M, Bébarová M, Šimurdová M, Šimurda J. Functional consequences of changes in the distribution of Ca 2+ extrusion pathways between t-tubular and surface membranes in a model of human ventricular cardiomyocyte. J Mol Cell Cardiol 2024:S0022-2828(24)00107-X. [PMID: 38960316 DOI: 10.1016/j.yjmcc.2024.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 06/10/2024] [Accepted: 06/29/2024] [Indexed: 07/05/2024]
Abstract
The sarcolemmal Ca2+ efflux pathways, Na+-Ca2+-exchanger (NCX) and Ca2+-ATPase (PMCA), play a crucial role in the regulation of intracellular Ca2+ load and Ca2+ transient in cardiomyocytes. The distribution of these pathways between the t-tubular and surface membrane of ventricular cardiomyocytes varies between species and is not clear in human. Moreover, several studies suggest that this distribution changes during the development and heart diseases. However, the consequences of NCX and PMCA redistribution in human ventricular cardiomyocytes have not yet been elucidated. In this study, we aimed to address this point by using a mathematical model of the human ventricular myocyte incorporating t-tubules, dyadic spaces, and subsarcolemmal spaces. Effects of various combinations of t-tubular fractions of NCX and PMCA were explored, using values between 0.2 and 1 as reported in animal experiments under normal and pathological conditions. Small variations in the action potential duration (≤ 2%), but significant changes in the peak value of cytosolic Ca2+ transient (up to 17%) were observed at stimulation frequencies corresponding to the human heart rate at rest and during activity. The analysis of model results revealed that the changes in Ca2+ transient induced by redistribution of NCX and PMCA were mainly caused by alterations in Ca2+ concentrations in the subsarcolemmal spaces and cytosol during the diastolic phase of the stimulation cycle. The results suggest that redistribution of both transporters between the t-tubular and surface membranes contributes to changes in contractility in human ventricular cardiomyocytes during their development and heart disease and may promote arrhythmogenesis.
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Affiliation(s)
- Michal Pásek
- Institute of Thermomechanics, Czech Academy of Sciences, Prague, Czech Republic; Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.
| | - Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic; Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Milena Šimurdová
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jiří Šimurda
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
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Lietava S, Sepsi M, Zidkova J, Synkova I, Kozak M, Krivan L, Vlasinova J, Richter S, Rehor J, Kala P, Bebarova M, Novotny T. The yield of a comprehensive investigation protocol for the diagnosis of true idiopathic ventricular fibrillation in a real-life clinical setting. Sci Rep 2024; 14:14089. [PMID: 38890420 PMCID: PMC11189413 DOI: 10.1038/s41598-024-64513-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 06/10/2024] [Indexed: 06/20/2024] Open
Abstract
Traditionally, aborted cardiac arrest (ACA) due to documented ventricular fibrillation (VF) in the absence of structural heart disease has been termed idiopathic VF. By careful evaluation, a specific etiology can be found in a substantial proportion of patients. The aim of this survey was to assess the yield of an advanced diagnostic work-up to reveal a causative etiology in a real-life clinical setting. Patients from the University Hospital Brno's ACA database were analyzed (514 patients in total). Forty-six patients (31 males) fulfilled the inclusion criteria, which were: (1) absence of structural pathology on echocardiography; (2) absence of coronary artery disease; and (3) absence of reversible cause of ACA. The diagnostic work-up consisted in cardiac magnetic resonance imaging, stress testing, sodium channel blocker challenge, and genetic testing according to the availability of the method and patient compliance. A specific disease was found in 17 individuals (37.0%), although at least one diagnostic step was refused by 13 patients (28.3%). True idiopathic VF was confirmed in 7 patients (15.2%), for whom the entire diagnostic work-up did not reveal any specific pathology. Our real-life survey shows that, even with an incomplete diagnostic work-up (due to the unavailability of a particular method or variable patient compliance), a specific diagnosis can be identified in more than one third of the cases of "idiopathic" VF, which can thus enable targeted treatment and family screening.
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Affiliation(s)
- Samuel Lietava
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Milan Sepsi
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic.
| | - Jana Zidkova
- Centre of Molecular Biology and Genetics, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Iva Synkova
- Centre of Molecular Biology and Genetics, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Milan Kozak
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Lubomir Krivan
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Jitka Vlasinova
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Svatopluk Richter
- Department of Radiology and Nuclear Medicine, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Jan Rehor
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Petr Kala
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
| | - Marketa Bebarova
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Tomas Novotny
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavska 20, 625 00, Brno, Czech Republic
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Song Y, Zheng Z, Lian J. Deciphering Common Long QT Syndrome Using CRISPR/Cas9 in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Front Cardiovasc Med 2022; 9:889519. [PMID: 35647048 PMCID: PMC9136094 DOI: 10.3389/fcvm.2022.889519] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
From carrying potentially pathogenic genes to severe clinical phenotypes, the basic research in the inherited cardiac ion channel disease such as long QT syndrome (LQTS) has been a significant challenge in explaining gene-phenotype heterogeneity. These have opened up new pathways following the parallel development and successful application of stem cell and genome editing technologies. Stem cell-derived cardiomyocytes and subsequent genome editing have allowed researchers to introduce desired genes into cells in a dish to replicate the disease features of LQTS or replace causative genes to normalize the cellular phenotype. Importantly, this has made it possible to elucidate potential genetic modifiers contributing to clinical heterogeneity and hierarchically manage newly identified variants of uncertain significance (VUS) and more therapeutic options to be tested in vitro. In this paper, we focus on and summarize the recent advanced application of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) combined with clustered regularly interspaced short palindromic repeats/CRISPR-associated system 9 (CRISPR/Cas9) in the interpretation for the gene-phenotype relationship of the common LQTS and presence challenges, increasing our understanding of the effects of mutations and the physiopathological mechanisms in the field of cardiac arrhythmias.
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Affiliation(s)
- Yongfei Song
- Department of Cardiovascular, Ningbo Institute of Innovation for Combined Medicine and Engineering, Ningbo, China
- Yongfei Song
| | - Zequn Zheng
- Department of Cardiovascular, Medical College, Ningbo University, Ningbo, China
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo, China
| | - Jiangfang Lian
- Department of Cardiovascular, Ningbo Institute of Innovation for Combined Medicine and Engineering, Ningbo, China
- Department of Cardiovascular, Medical College, Ningbo University, Ningbo, China
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo, China
- *Correspondence: Jiangfang Lian
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Harvey A, Curnier D, Dodin P, Abadir S, Jacquemet V, Caru M. OUP accepted manuscript. Eur J Prev Cardiol 2022; 29:1633-1677. [PMID: 35537006 DOI: 10.1093/eurjpc/zwac081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022]
Abstract
Current exercise recommendations make it difficult for long QT syndrome (LQTS) patients to adopt a physically active and/or athletic lifestyle. The purpose of this review is to summarize the current evidence, identify knowledge gaps, and discuss research perspectives in the field of exercise and LQTS. The first aim is to document the influence of exercise training, exercise stress, and postural change interventions on ventricular repolarization in LQTS patients, while the second aim is to describe electrophysiological measurements used to study the above. Studies examining the effects of exercise on congenital or acquired LQTS in human subjects of all ages were included. Systematic searches were performed on 1 October 2021, through PubMed (NLM), Ovid Medline, Ovid All EBM Reviews, Ovid Embase, and ISI Web of Science, and limited to articles written in English or French. A total of 1986 LQTS patients and 2560 controls were included in the 49 studies. Studies were mainly case-control studies (n = 41) and examined exercise stress and/or postural change interventions (n = 48). One study used a 3-month exercise training program. Results suggest that LQTS patients have subtype-specific repolarization responses to sympathetic stress. Measurement methods and quality were found to be very heterogeneous, which makes inter-study comparisons difficult. In the absence of randomized controlled trials, the current recommendations may have long-term risks for LQTS patients who are discouraged from performing physical activity, rendering its associated health benefits out of range. Future research should focus on discovering the most appropriate levels of exercise training that promote ventricular repolarization normalization in LQTS.
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Affiliation(s)
- Audrey Harvey
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Daniel Curnier
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Philippe Dodin
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Sylvia Abadir
- Department of Pediatric Cardiology, Sainte-Justine University Health Center, Montreal, Canada
| | - Vincent Jacquemet
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Maxime Caru
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, USA
- Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, PA, USA
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