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Romero G, Martin B, Gabris B, Salama G. Relaxin suppresses atrial fibrillation, reverses fibrosis and reduces inflammation in aged hearts. Biochem Pharmacol 2024; 227:116407. [PMID: 38969298 DOI: 10.1016/j.bcp.2024.116407] [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: 03/19/2024] [Revised: 06/18/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
Healthy aging results in cardiac structural and electrical remodeling that increase susceptibility to cardiovascular diseases. Relaxin has shown broad cardioprotective effects including anti-fibrotic, anti-arrhythmic and anti-inflammatory outcomes in multiple models. This paper focuses on the cardioprotective effects of Relaxin in a rat model of aging. Sustained atrial or ventricular fibrillation are readily induced in the hearts of aged but not young control animals. Treatment with Relaxin suppressed this arrhythmogenic response by increasing conduction velocity, decreasing fibrosis and promoting substantial cardiac remodeling. Relaxin treatment resulted in a significant increase in the levels of: Nav1.5, Cx43, βcatenin and Wnt1 in rat hearts. In isolated cardiomyocytes, Relaxin increased Nav1.5 expression. These effects were mimicked by CHIR 99021, a pharmacological activator of canonical Wnt signaling, but blocked by the canonical Wnt inhibitor Dickkopf1. Relaxin prevented TGF-β-dependent differentiation of cardiac fibroblasts into myofibroblasts while increasing the expression of Wnt1; the effects of Relaxin on cardiac fibroblast differentiation were blocked by Dickkopf1. RNASeq studies demonstrated reduced expression of pro-inflammatory cytokines and an increase in the expression of α- and β-globin in Relaxin-treated aged males. Relaxin reduces arrhythmogenicity in the hearts of aged rats by reduction of fibrosis and increased conduction velocity. These changes are accompanied by substantial remodeling of the cardiac tissue and appear to be mediated by increased canonical Wnt signaling. Relaxin also exerts significant anti-inflammatory and anti-oxidant effects in the hearts of aged rodents. The mechanisms by which Relaxin increases the expression of Wnt ligands, promotes Wnt signaling and reprograms gene expression remain to be determined.
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Affiliation(s)
- Guillermo Romero
- Departments of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Brian Martin
- Departments of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Beth Gabris
- Departments of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Guy Salama
- Departments of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Song T, Hui W, Huang M, Guo Y, Yu M, Yang X, Liu Y, Chen X. Dynamic Changes in Ion Channels during Myocardial Infarction and Therapeutic Challenges. Int J Mol Sci 2024; 25:6467. [PMID: 38928173 PMCID: PMC11203447 DOI: 10.3390/ijms25126467] [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: 04/20/2024] [Revised: 06/02/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
In different areas of the heart, action potential waveforms differ due to differences in the expressions of sodium, calcium, and potassium channels. One of the characteristics of myocardial infarction (MI) is an imbalance in oxygen supply and demand, leading to ion imbalance. After MI, the regulation and expression levels of K+, Ca2+, and Na+ ion channels in cardiomyocytes are altered, which affects the regularity of cardiac rhythm and leads to myocardial injury. Myocardial fibroblasts are the main effector cells in the process of MI repair. The ion channels of myocardial fibroblasts play an important role in the process of MI. At the same time, a large number of ion channels are expressed in immune cells, which play an important role by regulating the in- and outflow of ions to complete intracellular signal transduction. Ion channels are widely distributed in a variety of cells and are attractive targets for drug development. This article reviews the changes in different ion channels after MI and the therapeutic drugs for these channels. We analyze the complex molecular mechanisms behind myocardial ion channel regulation and the challenges in ion channel drug therapy.
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Affiliation(s)
- Tongtong Song
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
- Department of Anatomy, College of Basic Medical Sciences, Jilin University, Changchun 130012, China
| | - Wenting Hui
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Min Huang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Yan Guo
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Meiyi Yu
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Xiaoyu Yang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Yanqing Liu
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Xia Chen
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
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Ciaccio EJ, Cedilnik N, Hsia HH, Biviano AB, Garan H, Yarmohammadi H. Wavefront curvature analysis derived from preprocedural imaging can identify the critical isthmus in patients with postinfarcted ventricular tachycardia. Heart Rhythm 2024:S1547-5271(24)02669-9. [PMID: 38848858 DOI: 10.1016/j.hrthm.2024.05.056] [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: 04/29/2024] [Revised: 05/29/2024] [Accepted: 05/30/2024] [Indexed: 06/09/2024]
Abstract
BACKGROUND Where activation wavefront curvature is convexly shaped, functional conduction block can occur. OBJECTIVE The purpose of this study was to determine whether left ventricular (LV) wall thickness determined from contrast-enhanced computed tomography (CT) is useful in localizing such areas in clinical postinfarction reentrant ventricular tachycardia (VT). METHODS We evaluated data from 6 patients who underwent catheter ablation for postinfarction VT. CT imaging with inHEART processing was conducted 1-3 days before electrophysiological (EP) study to determine LV wall thickness (T). Activation wavefront curvature was approximated as ΔT/T, where ΔT represents wall thickness change. During EP study, bipolar LV VT electrograms were acquired using a high-density mapping catheter, and activation times were determined. Maps of T, ΔT/T, and VT activation were subsequently compared using statistical analyses. RESULTS Two of 6 cases exhibited dual circuit morphologies, resulting in a total of 8 VT morphologies analyzed. The LV wall near the VT isthmus location tended to be thin, on the order of a few hundred micrometers. Regions of largest ΔT/T partially coincided with the lateral isthmus boundaries where electrical conduction block occurred during VT. ΔT/T at the boundaries, measured from imaging, was significantly larger compared to values at the isthmus midline and to the global LV mean value (P <.001). CONCLUSION Wavefront curvature measured by ΔT/T and caused by source-sink mismatch is dependent on ventricular wall thickness. Areas of high wavefront curvature partly coincide with and may be helpful in locating the VT isthmus in infarct border zones using preprocedural imaging analysis.
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Affiliation(s)
- Edward J Ciaccio
- Department of Medicine, Division of Cardiology, College of Physicians and Surgeons, Columbia University, New York, New York.
| | - Nicolas Cedilnik
- inHEART Medical, IHU Liryc, Hopital Xavier Arnozan, Pessac, France
| | - Henry H Hsia
- Cardiac Electrophysiology and Arrhythmia Service, University of California San Francisco, San Francisco, California
| | - Angelo B Biviano
- Department of Medicine, Division of Cardiology, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Hasan Garan
- Department of Medicine, Division of Cardiology, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Hirad Yarmohammadi
- Department of Medicine, Division of Cardiology, College of Physicians and Surgeons, Columbia University, New York, New York
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Ciaccio EJ, Coromilas J, Saluja DS, Hsia HH, Peters NS, Yarmohammadi H. Sinus rhythm activation signature indicates reentrant ventricular tachycardia inducibility and approximate isthmus location. Heart Rhythm 2024:S1547-5271(24)02517-7. [PMID: 38677360 DOI: 10.1016/j.hrthm.2024.04.082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/18/2024] [Accepted: 04/20/2024] [Indexed: 04/29/2024]
Abstract
BACKGROUND Sinus rhythm activation time is useful to assess infarct border zone substrate. OBJECTIVE We sought to further investigate sinus activation in ventricular tachycardia (VT). METHODS Canine postinfarction data were analyzed retrospectively. In each experiment, an infarct was created in the left ventricular wall by left anterior descending coronary artery ligation. At 3 to 5 days after ligation, 196-312 bipolar electrograms were recorded from the anterior left ventricular epicardium overlapping the infarct border zone. Sustained monomorphic VT was induced by premature electrical stimulation in 50 experiments and was noninducible in 43 experiments. Acquired sinus rhythm and VT electrograms were marked for electrical activation time, and activation maps of representative sinus rhythm and VT cycles were constructed. The sinus rhythm activation signature was defined as the cumulative number of multielectrode recording sites that had activated per time epoch, and its derivative was used to predict VT inducibility and to define the sinus rhythm slow/late activation sequence. RESULTS Plotting mean activation signature derivative, a best cutoff value was useful to separate experiments with reentrant VT inducibility (sensitivity, 42/50) vs noninducibility (specificity, 39/43), with an accuracy of 81 of 93. For the 50 experiments with inducible VT, recording sites overlying a segment of isochrone encompassing the sinus rhythm slow/late activation sequence spanned the VT isthmus location in 32 cases (64%), partially spanned it in 15 cases (30%), but did not span it in 3 cases (6%). CONCLUSION The sinus rhythm activation signature derivative is assistive to differentiate substrate supporting reentrant VT inducibility vs noninducibility and to identify slow/late activation for targeting isthmus location.
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Affiliation(s)
- Edward J Ciaccio
- Division of Cardiology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York; ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, United Kingdom.
| | - James Coromilas
- Division of Cardiovascular Disease and Hypertension, Department of Medicine, Rutgers University, New Brunswick, New Jersey
| | - Deepak S Saluja
- Division of Cardiology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
| | - Henry H Hsia
- Cardiac Electrophysiology and Arrhythmia Service, Department of Medicine, University of California, San Francisco, California
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, United Kingdom
| | - Hirad Yarmohammadi
- Division of Cardiology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
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Willems E, Janssens KLPM, Dekker LRC, van de Vosse FN, Cluitmans MJM, Bovendeerd PHM. Strain-controlled electrophysiological wave propagation alters in silico scar-based substrate for ventricular tachycardia. Front Physiol 2024; 15:1330157. [PMID: 38655031 PMCID: PMC11036413 DOI: 10.3389/fphys.2024.1330157] [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: 10/30/2023] [Accepted: 03/21/2024] [Indexed: 04/26/2024] Open
Abstract
Introduction: Assessing a patient's risk of scar-based ventricular tachycardia (VT) after myocardial infarction is a challenging task. It can take months to years after infarction for VT to occur. Also, if selected for ablation therapy, success rates are low. Methods: Computational ventricular models have been presented previously to support VT risk assessment and to provide ablation guidance. In this study, an extension to such virtual-heart models is proposed to phenomenologically incorporate tissue remodeling driven by mechanical load. Strain amplitudes in the heart muscle are obtained from simulations of mechanics and are used to adjust the electrical conductivity. Results: The mechanics-driven adaptation of electrophysiology resulted in a more heterogeneous distribution of propagation velocities than that of standard models, which adapt electrophysiology in the structural substrate from medical images only. Moreover, conduction slowing was not only present in such a structural substrate, but extended in the adjacent functional border zone with impaired mechanics. This enlarged the volumes with high repolarization time gradients (≥10 ms/mm). However, maximum gradient values were not significantly affected. The enlarged volumes were localized along the structural substrate border, which lengthened the line of conduction block. The prolonged reentry pathways together with conduction slowing in functional regions increased VT cycle time, such that VT was easier to induce, and the number of recommended ablation sites increased from 3 to 5 locations. Discussion: Sensitivity testing showed an accurate model of strain-dependency to be critical for low ranges of conductivity. The model extension with mechanics-driven tissue remodeling is a potential approach to capture the evolution of the functional substrate and may offer insight into the progression of VT risk over time.
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Affiliation(s)
- Evianne Willems
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Koen L. P. M. Janssens
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Lukas R. C. Dekker
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Department of Cardiology, Catharina Hospital, Eindhoven, Netherlands
| | - Frans N. van de Vosse
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Matthijs J. M. Cluitmans
- Maastricht University Medical Center, Maastricht, Netherlands
- Philips Research Eindhoven, Eindhoven, Netherlands
| | - Peter H. M. Bovendeerd
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
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6
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Padget RL, Zeitz MJ, Blair GA, Wu X, North MD, Tanenbaum MT, Stanley KE, Phillips CM, King DR, Lamouille S, Gourdie RG, Hoeker GS, Swanger SA, Poelzing S, Smyth JW. Acute Adenoviral Infection Elicits an Arrhythmogenic Substrate Prior to Myocarditis. Circ Res 2024; 134:892-912. [PMID: 38415360 PMCID: PMC11003857 DOI: 10.1161/circresaha.122.322437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/12/2024] [Indexed: 02/29/2024]
Abstract
BACKGROUND Viral cardiac infection represents a significant clinical challenge encompassing several etiological agents, disease stages, complex presentation, and a resulting lack of mechanistic understanding. Myocarditis is a major cause of sudden cardiac death in young adults, where current knowledge in the field is dominated by later disease phases and pathological immune responses. However, little is known regarding how infection can acutely induce an arrhythmogenic substrate before significant immune responses. Adenovirus is a leading cause of myocarditis, but due to species specificity, models of infection are lacking, and it is not understood how adenoviral infection may underlie sudden cardiac arrest. Mouse adenovirus type-3 was previously reported as cardiotropic, yet it has not been utilized to understand the mechanisms of cardiac infection and pathology. METHODS We have developed mouse adenovirus type-3 infection as a model to investigate acute cardiac infection and molecular alterations to the infected heart before an appreciable immune response or gross cardiomyopathy. RESULTS Optical mapping of infected hearts exposes decreases in conduction velocity concomitant with increased Cx43Ser368 phosphorylation, a residue known to regulate gap junction function. Hearts from animals harboring a phospho-null mutation at Cx43Ser368 are protected against mouse adenovirus type-3-induced conduction velocity slowing. Additional to gap junction alterations, patch clamping of mouse adenovirus type-3-infected adult mouse ventricular cardiomyocytes reveals prolonged action potential duration as a result of decreased IK1 and IKs current density. Turning to human systems, we find human adenovirus type-5 increases phosphorylation of Cx43Ser368 and disrupts synchrony in human induced pluripotent stem cell-derived cardiomyocytes, indicating common mechanisms with our mouse whole heart and adult cardiomyocyte data. CONCLUSIONS Together, these findings demonstrate that adenoviral infection creates an arrhythmogenic substrate through direct targeting of gap junction and ion channel function in the heart. Such alterations are known to precipitate arrhythmias and likely contribute to sudden cardiac death in acutely infected patients.
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Affiliation(s)
- Rachel L. Padget
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Michael J. Zeitz
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Grace A. Blair
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Xiaobo Wu
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Michael D. North
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
| | | | - Kari E. Stanley
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Chelsea M. Phillips
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - D. Ryan King
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Samy Lamouille
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Robert G. Gourdie
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, College of Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Gregory S. Hoeker
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Sharon A. Swanger
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA
| | - Steven Poelzing
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, College of Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - James W. Smyth
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, College of Engineering, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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Li J, Ma ZY, Cui YF, Cui YT, Dong XH, Wang YZ, Fu YY, Xue YD, Tong TT, Ding YZ, Zhu YM, Huang HJ, Zhao L, Lv HZ, Xiong LZ, Zhang K, Han YX, Ban T, Huo R. Cardiac-specific deletion of BRG1 ameliorates ventricular arrhythmia in mice with myocardial infarction. Acta Pharmacol Sin 2024; 45:517-530. [PMID: 37880339 PMCID: PMC10834533 DOI: 10.1038/s41401-023-01170-y] [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: 05/22/2023] [Accepted: 09/14/2023] [Indexed: 10/27/2023] Open
Abstract
Malignant ventricular arrhythmia (VA) after myocardial infarction (MI) is mainly caused by myocardial electrophysiological remodeling. Brahma-related gene 1 (BRG1) is an ATPase catalytic subunit that belongs to a family of chromatin remodeling complexes called Switch/Sucrose Non-Fermentable Chromatin (SWI/SNF). BRG1 has been reported as a molecular chaperone, interacting with various transcription factors or proteins to regulate transcription in cardiac diseases. In this study, we investigated the potential role of BRG1 in ion channel remodeling and VA after ischemic infarction. Myocardial infarction (MI) mice were established by ligating the left anterior descending (LAD) coronary artery, and electrocardiogram (ECG) was monitored. Epicardial conduction of MI mouse heart was characterized in Langendorff-perfused hearts using epicardial optical voltage mapping. Patch-clamping analysis was conducted in single ventricular cardiomyocytes isolated from the mice. We showed that BRG1 expression in the border zone was progressively increased in the first week following MI. Cardiac-specific deletion of BRG1 by tail vein injection of AAV9-BRG1-shRNA significantly ameliorated susceptibility to electrical-induced VA and shortened QTc intervals in MI mice. BRG1 knockdown significantly enhanced conduction velocity (CV) and reversed the prolonged action potential duration in MI mouse heart. Moreover, BRG1 knockdown improved the decreased densities of Na+ current (INa) and transient outward potassium current (Ito), as well as the expression of Nav1.5 and Kv4.3 in the border zone of MI mouse hearts and in hypoxia-treated neonatal mouse ventricular cardiomyocytes. We revealed that MI increased the binding among BRG1, T-cell factor 4 (TCF4) and β-catenin, forming a transcription complex, which suppressed the transcription activity of SCN5A and KCND3, thereby influencing the incidence of VA post-MI.
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Affiliation(s)
- Jing Li
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Zi-Yue Ma
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Yun-Feng Cui
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ying-Tao Cui
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Xian-Hui Dong
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Yong-Zhen Wang
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Yu-Yang Fu
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ya-Dong Xue
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ting-Ting Tong
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ying-Zi Ding
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ya-Mei Zhu
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Hai-Jun Huang
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ling Zhao
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Hong-Zhao Lv
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Ling-Zhao Xiong
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Kai Zhang
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Yu-Xuan Han
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China
| | - Tao Ban
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China.
- Heilongjiang Academy of Medical Sciences, Baojian Road, Nangang District, Harbin, 150081, China.
| | - Rong Huo
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Baojian Road, Nangang District, Harbin, 150081, China.
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8
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Yang F, Zhang XL, Liu HH, Qian LL, Wang RX. Post translational modifications of connexin 43 in ventricular arrhythmias after myocardial infarction. Mol Biol Rep 2024; 51:329. [PMID: 38393658 DOI: 10.1007/s11033-024-09290-2] [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: 10/31/2023] [Accepted: 01/26/2024] [Indexed: 02/25/2024]
Abstract
Ventricular arrhythmias are the leading cause of sudden cardiac death in patients after myocardial infarction (MI). Connexin43 (Cx43) is the most important gap junction channel-forming protein in cardiomyocytes. Dysfunction of Cx43 contributes to impaired myocardial conduction and the development of ventricular arrhythmias. Following an MI, Cx43 undergoes structural remodeling, including expression abnormalities, and redistribution. These alterations detrimentally affect intercellular communication and electrical conduction within the myocardium, thereby increasing the susceptibility to post-infarction ventricular arrhythmias. Emerging evidence suggests that post-translational modifications play essential roles in Cx43 regulation after MI. Therefore, Cx43-targeted management has the potential to be a promising protective strategy for the prevention and treatment of post infarction ventricular arrhythmias. In this article, we primarily reviewed the regulatory mechanisms of Cx43 mediated post-translational modifications on post-infarction ventricular arrhythmias. Furthermore, Cx43-targeted therapy have also been discussed, providing insights into an innovative treatment strategy for ventricular arrhythmias after MI.
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Affiliation(s)
- Fan Yang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China
| | - Xiao-Lu Zhang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China
| | - Huan-Huan Liu
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China.
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China.
- Wuxi School of Medicine, Jiangnan University, Wuxi, China.
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9
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Ciaccio EJ, Saluja DS, Peters NS, Yarmohammadi H. Role of activation signatures in re-entrant ventricular tachycardia circuits. J Cardiovasc Electrophysiol 2024; 35:267-277. [PMID: 38073065 DOI: 10.1111/jce.16146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/07/2023] [Accepted: 11/21/2023] [Indexed: 02/07/2024]
Abstract
INTRODUCTION Development of a rapid means to verify the ventricular tachycardia (VT) isthmus location from heart surface electrogram recordings would be a helpful tool for the electrophysiologist. METHOD Myocardial infarction was induced in 22 canines by left anterior descending coronary artery ligation under general anesthesia. After 3-5 days, VT was inducible via programmed electrical stimulation at the anterior left ventricular epicardial surface. Bipolar VT electrograms were acquired from 196 to 312 recording sites using a multielectrode array. Electrograms were marked for activation time, and activation maps were constructed. The activation signal, or signature, is defined as the cumulative number of recording sites that have activated per millisecond, and it was utilized to segment each circuit into inner and outer circuit pathways, and as an estimate of best ablation lesion location to prevent VT. RESULTS VT circuit components were differentiable by activation signals as: inner pathway (mean: 0.30 sites activating/ms) and outer pathway (mean: 2.68 sites activating/ms). These variables were linearly related (p < .001). Activation signal characteristics were dependent in part upon the isthmus exit site. The inner circuit pathway determined by the activation signal overlapped and often extended beyond the activation map isthmus location for each circuit. The best lesion location estimated by the activation signal would likely block an electrical impulse traveling through the isthmus, to prevent VT in all circuits. CONCLUSIONS The activation signal algorithm, simple to implement for real-time computer display, approximates the VT isthmus location and shape as determined from activation marking, and best ablation lesion location to prevent reinduction.
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Affiliation(s)
- Edward J Ciaccio
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, Columbia University, New York, New York, USA
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Deepak S Saluja
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Hirad Yarmohammadi
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, Columbia University, New York, New York, USA
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10
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Zheng L, Shi W, Liu B, Duan B, Sorgen P. Evaluation of Tyrosine Kinase Inhibitors Loaded Injectable Hydrogels for Improving Connexin43 Gap Junction Intercellular Communication. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1985-1998. [PMID: 38175743 PMCID: PMC11061860 DOI: 10.1021/acsami.3c10923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Myocardial infarction (MI) is one of the leading causes of death in the developed world, and the loss of cardiomyocytes plays a critical role in the pathogenesis of heart failure. Implicated in this process is a decrease in gap junction intercellular communication due to remodeling of Connexin43 (Cx43). We previously identified that intraperitoneal injection of the Pyk2 inhibitor PF4618433 reduced infarct size, maintained Cx43 at the intercalated disc in left ventricle hypertrophic myocytes, and improved cardiac function in an MI animal model of heart failure. With the emergence of injectable hydrogels as a therapeutic toward the regeneration of cardiac tissue after MI, here, we provide proof of concept that the release of tyrosine kinase inhibitors from hydrogels could have beneficial effects on cardiomyocytes. We developed an injectable hydrogel consisting of thiolated hyaluronic acid and P123-maleimide micelles that can incorporate PF4618433 as well as the Src inhibitor Saracatinib and achieved sustained release (of note, Src activates Pyk2). Using neonatal rat ventricular myocytes in the presence of a phorbol ester, endothelin-1, or phenylephrine to stimulate cardiac hypertrophy, the release of PF4618433 from the hydrogel had the same ability to decrease Cx43 tyrosine phosphorylation and maintain Cx43 localization at the plasma membrane as when directly added to the growth media. Additional beneficial effects included decreases in apoptosis, the hypertrophic marker atrial natriuretic peptide (ANP), and serine kinases upregulated in hypertrophy. Finally, the presence of both PF4618433 and Saracatinib further decreased the level of ANP and apoptosis than each inhibitor alone, suggesting that a combinatorial approach may be most beneficial. These findings provide the groundwork to test if tyrosine kinase inhibitor release from hydrogels will have a beneficial effect in an animal model of MI-induced heart failure.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Wen Shi
- Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Division of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bo Liu
- Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Division of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bin Duan
- Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Division of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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11
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Morris JA, Bardsley OJ, Salvage SC, Jackson AP, Matthews HR, Huang CLH. Nernst-Planck-Gaussian modelling of electrodiffusional recovery from ephaptic excitation between mammalian cardiomyocytes. Front Physiol 2024; 14:1280151. [PMID: 38235384 PMCID: PMC10791825 DOI: 10.3389/fphys.2023.1280151] [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: 08/19/2023] [Accepted: 12/01/2023] [Indexed: 01/19/2024] Open
Abstract
Introduction: In addition to gap junction conduction, recent reports implicate possible ephaptic coupling contributions to action potential (AP) propagation between successive adjacent cardiomyocytes. Here, AP generation in an active cell, withdraws Na+ from, creating a negative potential within, ephaptic spaces between the participating membranes, activating the initially quiescent neighbouring cardiomyocyte. However, sustainable ephaptic transmission requires subsequent complete recovery of the ephaptic charge difference. We explore physical contributions of passive electrodiffusive ion exchange with the remaining extracellular space to this recovery for the first time. Materials and Methods: Computational, finite element, analysis examined limiting, temporal and spatial, ephaptic [Na+], [Cl-], and the consequent Gaussian charge differences and membrane potential recovery patterns following a ΔV∼130 mV AP upstroke at physiological (37°C) temperatures. This incorporated Nernst-Planck formalisms into equations for the time-dependent spatial concentration gradient profiles. Results: Mammalian atrial, ventricular and purkinje cardiomyocyte ephaptic junctions were modelled by closely apposed circularly symmetric membranes, specific capacitance 1 μF cm-2, experimentally reported radii a = 8,000, 12,000 and 40,000 nm respectively and ephaptic axial distance w = 20 nm. This enclosed an ephaptic space containing principal ions initially at normal extracellular [Na+] = 153.1 mM and [Cl-] = 145.8 mM, respective diffusion coefficients D Na = 1.3 × 109 and D Cl = 2 × 109 nm2s-1. Stable, concordant computational solutions were confirmed exploring ≤1,600 nm mesh sizes and Δt≤0.08 ms stepsize intervals. The corresponding membrane voltage profile changes across the initially quiescent membrane were obtainable from computed, graphically represented a and w-dependent ionic concentration differences adapting Gauss's flux theorem. Further simulations explored biological variations in ephaptic dimensions, membrane anatomy, and diffusion restrictions within the ephaptic space. Atrial, ventricular and Purkinje cardiomyocytes gave 40, 180 and 2000 ms 99.9% recovery times, with 720 or 360 ms high limits from doubling ventricular radius or halving diffusion coefficient. Varying a, and D Na and D Cl markedly affected recovery time-courses with logarithmic and double-logarithmic relationships, Varying w exerted minimal effects. Conclusion: We thereby characterise the properties of, and through comparing atrial, ventricular and purkinje recovery times with interspecies in vivo background cardiac cycle duration data, (blue whale ∼2000, human∼90, Etruscan shrew, ∼40 ms) can determine physical limits to, electrodiffusive contributions to ephaptic recovery.
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Affiliation(s)
- Joshua A. Morris
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Oliver J. Bardsley
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Samantha C. Salvage
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Antony P. Jackson
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Hugh R. Matthews
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Christopher L-H. Huang
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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12
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Ranjan P, Colin K, Dutta RK, Verma SK. Challenges and future scope of exosomes in the treatment of cardiovascular diseases. J Physiol 2023; 601:4873-4893. [PMID: 36398654 PMCID: PMC10192497 DOI: 10.1113/jp282053] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/21/2022] [Indexed: 07/28/2023] Open
Abstract
Exosomes are nanosized vesicles that carry biologically diverse molecules for intercellular communication. Researchers have been trying to engineer exosomes for therapeutic purposes by using different approaches to deliver biologically active molecules to the various target cells efficiently. Recent technological advances may allow the biodistribution and pharmacokinetics of exosomes to be modified to meet scientific needs with respect to specific diseases. However, it is essential to determine an exosome's optimal dosage and potential side effects before its clinical use. Significant breakthroughs have been made in recent decades concerning exosome labelling and imaging techniques. These tools provide in situ monitoring of exosome biodistribution and pharmacokinetics and pinpoint targetability. However, because exosomes are nanometres in size and vary significantly in contents, a deeper understanding is required to ensure accurate monitoring before they can be applied in clinical settings. Different research groups have established different approaches to elucidate the roles of exosomes and visualize their spatial properties. This review covers current and emerging strategies for in vivo and in vitro exosome imaging and tracking for potential studies.
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Affiliation(s)
- Prabhat Ranjan
- Department of Medicine, Division of Cardiovascular Disease, The University of Alabama at Birmingham, Birmingham, AL-35233
| | - Karen Colin
- Department of Medicine, Division of Cardiovascular Disease, The University of Alabama at Birmingham, Birmingham, AL-35233
- UAB School of Health Professions, The University of Alabama at Birmingham, Birmingham, AL
| | - Roshan Kumar Dutta
- Department of Medicine, Division of Cardiovascular Disease, The University of Alabama at Birmingham, Birmingham, AL-35233
| | - Suresh Kumar Verma
- Department of Medicine, Division of Cardiovascular Disease, The University of Alabama at Birmingham, Birmingham, AL-35233
- Department of Biomedical Engineering, The University of Alabama at Birmingham, Birmingham, Alabama
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13
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Yang S, Bi Y, Wei Y, Li W, Liu J, Mao T, Tang Y. Muscone attenuates susceptibility to ventricular arrhythmia by inhibiting NLRP3 inflammasome activation in rats after myocardial infarction. J Biochem Mol Toxicol 2023; 37:e23458. [PMID: 37455625 DOI: 10.1002/jbt.23458] [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: 12/08/2022] [Revised: 03/14/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
Fibrosis and abnormal expression of connexin 43 (Cx43) in the ventricle play vital roles in ventricular arrhythmias (VAs) after myocardial infarction (MI). Muscone, an active monomer of heart-protecting musk pill, has various biological activities, but its effect on susceptibility to VAs in rats with MI has not been determined. In the present study, we investigated the effects of muscone on ventricular inflammation, fibrosis, Cx43 expression, and the occurrence of VAs after MI. An MI model was established by ligating the proximal left anterior descending coronary artery. Then, the MI model rats were administered muscone (2 mg/kg/day) or vehicle (saline)via intragastric injection for 14 days. Cardiac function was evaluated by echocardiography, and an in vivo electrophysiological study was performed on Day 14. Cardiac inflammation, fibrosis, and Cx43 expression were determined by histochemical analysis and western blot analysis. Our results indicated that muscone treatment significantly improved cardiac function and inhibited ventricular inflammation, fibrosis, and nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 3 (NLRP3) inflammasome activation. Electrocardiogrphy and electrophysiology studies showed that muscone shortened the QRS interval, QT interval, QTc interval, and action potential duration; prolonged the effective refractory period; and reduced susceptibility to VAs in rats after MI. Furthermore, Cx43 expression in the BZ was increased by muscone treatment, and this change was coupled by inhibition of the NLRP3/IL-1β/p38 MAPK pathway. Taken together, our results demonstrated that muscone reduces susceptibility to VA, mainly by decreasing ventricular inflammation and fibrosis, and attenuates abnormal Cx43 expression by inhibiting NLRP3 inflammasome activation after myocardial infarction in rats.
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Affiliation(s)
- Shuang Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan University, Wuhan, People's Republic of China
| | - Yingying Bi
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan University, Wuhan, People's Republic of China
| | - Yanzhao Wei
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan University, Wuhan, People's Republic of China
| | - Wei Li
- Department of Cardiology, Wuhan No. 1 Hospital, Wuhan Hospital of Traditional Chinese and Western Medicine, Wuhan, People's Republic of China
| | - Jiangwen Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan University, Wuhan, People's Republic of China
| | - Tuohua Mao
- Department of Endocrinology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
| | - Yanhong Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan University, Wuhan, People's Republic of China
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14
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Zheng L, Spagnol G, Gandhi DR, Sharma K, Kumar V, Patel KP, Sorgen PL. Inhibition of Pyk2 Improves Cx43 Intercalated Disc Localization, Infarct Size, and Cardiac Function in Rats With Heart Failure. Circ Heart Fail 2023; 16:e010294. [PMID: 37465947 PMCID: PMC10524803 DOI: 10.1161/circheartfailure.122.010294] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/12/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND Heart failure causes changes in Cx43 (Connexin43) regulation that are associated with arrhythmic heart disease. Pyk2 (proline-rich tyrosine kinase 2) is activated in cardiomyopathies and phosphorylates Cx43 to decrease intercellular communication. This study was designed to determine if Pyk2 inhibition improves cardiac function in a myocardial infarction (MI)-induced heart failure model in rats. METHODS MI (ligation of left anterior descending artery) rats were treated with the Pyk2 inhibitor PF4618433. Hemodynamic and structural parameters were monitored in Sham (n=5), MI-vehicle (n=5), and MI-PF4618433 (n=8) groups. Heart tissues were collected after 6 weeks to assess Pyk2 and Cx43 protein level and localization. RESULTS PF4618433 produced no observed adverse effects and inhibited ventricular Pyk2. PF4618433 reduced the MI infarct size from 34% to 17% (P=0.007). PF4618433 improved stroke volume (P=0.031) and cardiac output (P=0.009) in comparison to MI-vehicle with values similar to the Sham group. PF4618433 also led to an increase in the ejection fraction (P=0.002) and fractional shortening (P=0.006) when compared with the MI-vehicle (32% and 35% improvement, respectively) yet were lower in comparison with the Sham group. Pyk2 inhibition decreased Cx43 tyrosine phosphorylation (P=0.043) and maintained Cx43 at the intercalated disc in the distal ventricle 6 weeks post-MI. CONCLUSIONS Unlike other attempts to decrease Cx43 remodeling after MI-induced heart failure, inhibition of Pyk2 activity maintained Cx43 at the intercalated disc. This may have aided in the reduced infarct size (acute time frame) and improved cardiac function (chronic time frame). Additionally, we provide evidence that Pyk2 is activated following MI in human left ventricle, implicating a novel potential target for therapy in patients with heart failure.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Devashri R. Gandhi
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kanika Sharma
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Vikas Kumar
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kaushik P. Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul L. Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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15
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Nielsen MS, van Opbergen CJM, van Veen TAB, Delmar M. The intercalated disc: a unique organelle for electromechanical synchrony in cardiomyocytes. Physiol Rev 2023; 103:2271-2319. [PMID: 36731030 PMCID: PMC10191137 DOI: 10.1152/physrev.00021.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
The intercalated disc (ID) is a highly specialized structure that connects cardiomyocytes via mechanical and electrical junctions. Although described in some detail by light microscopy in the 19th century, it was in 1966 that electron microscopy images showed that the ID represented apposing cell borders and provided detailed insight into the complex ID nanostructure. Since then, much has been learned about the ID and its molecular composition, and it has become evident that a large number of proteins, not all of them involved in direct cell-to-cell coupling via mechanical or gap junctions, reside at the ID. Furthermore, an increasing number of functional interactions between ID components are emerging, leading to the concept that the ID is not the sum of isolated molecular silos but an interacting molecular complex, an "organelle" where components work in concert to bring about electrical and mechanical synchrony. The aim of the present review is to give a short historical account of the ID's discovery and an updated overview of its composition and organization, followed by a discussion of the physiological implications of the ID architecture and the local intermolecular interactions. The latter will focus on both the importance of normal conduction of cardiac action potentials as well as the impact on the pathophysiology of arrhythmias.
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Affiliation(s)
- Morten S Nielsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Chantal J M van Opbergen
- The Leon Charney Division of Cardiology, New York University Grossmann School of Medicine, New York, New York, United States
| | - Toon A B van Veen
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mario Delmar
- The Leon Charney Division of Cardiology, New York University Grossmann School of Medicine, New York, New York, United States
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16
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Ciaccio EJ, Coromilas J, Wan EY, Yarmohammadi H, Saluja DS, Peters NS, Garan H, Biviano AB. Lateral Boundaries of the Ventricular Tachycardia Circuit Align With Sinus Rhythm Discontinuities. JACC Clin Electrophysiol 2023; 9:851-861. [PMID: 37227361 DOI: 10.1016/j.jacep.2022.11.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/08/2022] [Accepted: 11/20/2022] [Indexed: 05/26/2023]
Abstract
BACKGROUND Sinus rhythm electrical activation mapping can provide information regarding the ischemic re-entrant ventricular tachycardia (VT) circuit. The information gleaned may include the localization of sinus rhythm electrical discontinuities, which can be defined as arcs of disrupted electrical conduction with large activation time differences across the arc. OBJECTIVES This study sought to detect and localize sinus rhythm electrical discontinuities that might be present in activation maps constructed from infarct border zone electrograms. METHODS Monomorphic re-entrant VT with a double-loop circuit and central isthmus was repeatedly inducible by programmed electrical stimulation in the epicardial border zone of 23 postinfarction canine hearts. Sinus rhythm and VT activation maps were constructed from 196 to 312 bipolar electrograms acquired surgically at the epicardial surface and analyzed computationally. A complete re-entrant circuit was mappable from the epicardial electrograms of VT, and isthmus lateral boundary (ILB) locations were ascertained. The difference in sinus rhythm activation time across ILB locations, vs the central isthmus and vs the circuit periphery, was determined. RESULTS Sinus rhythm activation time differences averaged 14.4 milliseconds across the ILB vs 6.5 milliseconds at the central isthmus and 6.4 milliseconds at the periphery (ie, the outer circuit loop) (P ≤ 0.001). Locations with large sinus rhythm activation difference tended to overlap ILB (60.3% ± 23.2%) compared with their overlap with the entire grid (27.5% ± 18.5%) (P < 0.001). CONCLUSIONS Disrupted electrical conduction is evident as discontinuity in sinus rhythm activation maps, particularly at ILB locations. These areas may represent permanent fixtures relating to spatial differences in border zone electrical properties, caused in part by alterations in underlying infarct depth. The tissue properties producing sinus rhythm discontinuity at ILB may contribute to functional conduction block formation at VT onset.
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Affiliation(s)
- Edward J Ciaccio
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York, USA; ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, United Kingdom.
| | - James Coromilas
- Department of Medicine, Division of Cardiovascular Disease and Hypertension, Rutgers University, New Brunswick, New Jersey, USA
| | - Elaine Y Wan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Hirad Yarmohammadi
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Deepak S Saluja
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, United Kingdom
| | - Hasan Garan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Angelo B Biviano
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York, USA
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Rossi S, Statello R, Pelà G, Leonardi F, Cabassi A, Foresti R, Rozzi G, Lo Muzio FP, Carnevali L, Sgoifo A, Magnani L, Callegari S, Pastori P, Tafuni A, Corradi D, Miragoli M, Macchi E. Age-related increases in cardiac excitability, refractoriness and impulse conduction favor arrhythmogenesis in male rats. Pflugers Arch 2023; 475:731-745. [PMID: 37022463 DOI: 10.1007/s00424-023-02812-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/17/2023] [Accepted: 04/02/2023] [Indexed: 04/07/2023]
Abstract
The effects of excitability, refractoriness, and impulse conduction have been independently related to enhanced arrhythmias in the aged myocardium in experimental and clinical studies. However, their combined arrhythmic effects in the elderly are not yet completely understood. Hence, the aim of the present work is to relate relevant cardiac electrophysiological parameters to enhanced arrhythmia vulnerability in the in vivo senescent heart. We used multiple-lead epicardial potential mapping in control (9-month-old) and aged (24-month-old) rat hearts. Cardiac excitability and refractoriness were evaluated at numerous epicardial test sites by means of the strength-duration curve and effective refractory period, respectively. During sinus rhythm, durations of electrogram intervals and waves were prolonged in the senescent heart, compared with control, demonstrating a latency in tissue activation and recovery. During ventricular pacing, cardiac excitability, effective refractory period, and dispersion of refractoriness increased in the aged animal. This scenario was accompanied by impairment of impulse propagation. Moreover, both spontaneous and induced arrhythmias were increased in senescent cardiac tissue. Histopathological evaluation of aged heart specimens revealed connective tissue deposition and perinuclear myocytolysis in the atria, while scattered microfoci of interstitial fibrosis were mostly present in the ventricular subendocardium. This work suggests that enhanced arrhythmogenesis in the elderly is a multifactorial process due to the joint increase in excitability and dispersion of refractoriness in association with enhanced conduction inhomogeneity. The knowledge of these electrophysiological changes will possibly contribute to improved prevention of the age-associated increase in cardiac arrhythmias.
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Affiliation(s)
- Stefano Rossi
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy.
- Centro Di Eccellenza Per La Ricerca Tossicologica, CERT, University of Parma, Parma, Italy.
| | - Rosario Statello
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Giovanna Pelà
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
| | - Fabio Leonardi
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - Aderville Cabassi
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
| | - Ruben Foresti
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
| | - Giacomo Rozzi
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
- Humanitas Clinical and Research Center, IRCCS, Rozzano, Milan, Italy
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Luca Carnevali
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Andrea Sgoifo
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Luca Magnani
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Sergio Callegari
- Centro Di Eccellenza Per La Ricerca Tossicologica, CERT, University of Parma, Parma, Italy
| | - Paolo Pastori
- Division of Cardiology, Ospedale Di Fidenza, Fidenza, Italy
| | - Alessandro Tafuni
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
| | - Domenico Corradi
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
- Centro Di Eccellenza Per La Ricerca Tossicologica, CERT, University of Parma, Parma, Italy
| | - Michele Miragoli
- Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43125, Parma, Italy
- Centro Di Eccellenza Per La Ricerca Tossicologica, CERT, University of Parma, Parma, Italy
- Humanitas Clinical and Research Center, IRCCS, Rozzano, Milan, Italy
| | - Emilio Macchi
- Centro Di Eccellenza Per La Ricerca Tossicologica, CERT, University of Parma, Parma, Italy
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
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Vlachos K, Letsas KP, Srinivasan NT, Frontera A, Efremidis M, Dragasis S, Martin CA, Martin R, Nakashima T, Bazoukis G, Kitamura T, Mililis P, Saplaouras A, Georgopoulos S, Sofoulis S, Kariki O, Koskina S, Takigawa M, Sacher F, Jais P, Santangeli P. The value of functional substrate mapping in ventricular tachycardia ablation. Heart Rhythm O2 2023; 4:134-146. [PMID: 36873315 PMCID: PMC9975018 DOI: 10.1016/j.hroo.2022.10.013] [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] [Indexed: 11/27/2022] Open
Abstract
In the setting of structural heart disease, ventricular tachycardia (VT) is typically associated with a re-entrant mechanism. In patients with hemodynamically tolerated VTs, activation and entrainment mapping remain the gold standard for the identification of the critical parts of the circuit. However, this is rarely accomplished, as most VTs are not hemodynamically tolerated to permit mapping during tachycardia. Other limitations include noninducibility of arrhythmia or nonsustained VT. This has led to the development of substrate mapping techniques during sinus rhythm, eliminating the need for prolonged periods of mapping during tachycardia. Recurrence rates following VT ablation are high; therefore, new mapping techniques for substrate characterization are required. Advances in catheter technology and especially multielectrode mapping of abnormal electrograms has increased the ability to identify the mechanism of scar-related VT. Several substrate-guided approaches have been developed to overcome this, including scar homogenization and late potential mapping. Dynamic substrate changes are mainly identified within regions of myocardial scar and can be identified as local abnormal ventricular activities. Furthermore, mapping strategies incorporating ventricular extrastimulation, including from different directions and coupling intervals, have been shown to increase the accuracy of substrate mapping. The implementation of extrastimulus substrate mapping and automated annotation require less extensive ablation and would make VT ablation procedures less cumbersome and accessible to more patients.
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Affiliation(s)
- Konstantinos Vlachos
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- Electrophysiology Department, Onassis Cardiac Surgery Center, Athens, Greece
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
- Address reprint requests and correspondence: Dr Konstantinos Vlachos, Onassis Cardiac Surgery Center, Electrophysiology Department, Syggrou Avenue 356, PC 176 74, Athens, Greece.
| | | | - Neil T. Srinivasan
- Department of Cardiac Electrophysiology, Essex Cardiothoracic Centre, Basildon, United Kingdom
- Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - Antonio Frontera
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - Michael Efremidis
- Electrophysiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Stelios Dragasis
- Electrophysiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Claire A. Martin
- Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia, Cyprus
| | - Ruaridh Martin
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - Takashi Nakashima
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - George Bazoukis
- Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia, Cyprus
- Department of Cardiology, Larnaca General Hospital, Larnaca, Cyprus
| | - Takeshi Kitamura
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - Panagiotis Mililis
- Laboratory of Cardiac Electrophysiology, General Hospital of Athens Evangelismos, Athens, Greece
| | | | - Stamatios Georgopoulos
- Laboratory of Cardiac Electrophysiology, General Hospital of Athens Evangelismos, Athens, Greece
| | - Stamatios Sofoulis
- Electrophysiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Ourania Kariki
- Electrophysiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Stavroula Koskina
- Electrophysiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Masateru Takigawa
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - Frédéric Sacher
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - Pierre Jais
- Cardiac Pacing and Electrophysiology Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France
- INSERM U1045, Institut hostpialo-universitaire–L’institut de rythmologie et modélisation cardiaque, Centre Hospitalier Universitaire de Bordeaux, Université de Bordeaux, Pessac, France
| | - Pasquale Santangeli
- Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
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19
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Pun R, Kim MH, North BJ. Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease. Front Cardiovasc Med 2023; 9:1080131. [PMID: 36712244 PMCID: PMC9877470 DOI: 10.3389/fcvm.2022.1080131] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.
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Affiliation(s)
- Renju Pun
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Michael H. Kim
- CHI Health Heart Institute, School of Medicine, Creighton University, Omaha, NE, United States
| | - Brian J. North
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States,*Correspondence: Brian J. North,
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Abstract
Gap junctions, comprising connexin proteins, create conduits directly coupling the cytoplasms of adjacent cells. Expressed in essentially all tissues, dynamic gap junction structures enable the exchange of small molecules including ions and second messengers, and are central to maintenance of homeostasis and synchronized excitability. With such diverse and critical roles throughout the body, it is unsurprising that alterations to gap junction and/or connexin expression and function underlie a broad array of age-related pathologies. From neurological dysfunction to cardiac arrhythmia and bone loss, it is hard to identify a human disease state that does not involve reduced, or in some cases inappropriate, intercellular communication to affect organ function. With a complex life cycle encompassing several key regulatory steps, pathological gap junction remodeling during ageing can arise from alterations in gene expression, translation, intracellular trafficking, and posttranslational modification of connexins. Connexin proteins are now known to "moonlight" and perform a variety of non-junctional functions in the cell, independent of gap junctions. Furthermore, connexin "hemichannels" on the cell surface can communicate with the extracellular space without ever coupling to an adjacent cell to form a gap junction channel. This chapter will focus primarily on gap junctions in ageing, but such non-junctional connexin functions will be referred to where appropriate and the full spectrum of connexin biology should be noted as potentially causative/contributing to some findings in connexin knockout animals, for example.
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Affiliation(s)
- Michael J Zeitz
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA.,FBRI Center for Vascular and Heart Research, Roanoke, VA, USA
| | - James W Smyth
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA. .,FBRI Center for Vascular and Heart Research, Roanoke, VA, USA. .,Department of Biological Sciences, College of Science, Virginia Tech, Blacksburg, VA, USA. .,Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA.
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21
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Jing Y, Yang R, Chen W, Ye Q. Anti-Arrhythmic Effects of Sodium-Glucose Co-Transporter 2 Inhibitors. Front Pharmacol 2022; 13:898718. [PMID: 35814223 PMCID: PMC9263384 DOI: 10.3389/fphar.2022.898718] [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: 03/17/2022] [Accepted: 05/04/2022] [Indexed: 12/11/2022] Open
Abstract
Arrhythmias are clinically prevalent with a high mortality rate. They impose a huge economic burden, thereby substantially affecting the quality of life. Sodium-glucose co-transporter 2 inhibitor (SGLT2i) is a new type of hypoglycemic drug, which can regulate blood glucose level safely and effectively. Additionally, it reduces the occurrence and progression of heart failure and cardiovascular events significantly. Recently, studies have found that SGLT2i can alleviate the occurrence and progression of cardiac arrhythmias; however, the exact mechanism remains unclear. In this review, we aimed to discuss and summarize new literature on different modes in which SGLT2i ameliorates the occurrence and development of cardiac arrhythmias.
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22
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Callans DJ, Donahue JK. Repolarization Heterogeneity in Human Post-Infarct Ventricular Tachycardia. JACC Clin Electrophysiol 2022; 8:713-718. [PMID: 35738846 DOI: 10.1016/j.jacep.2022.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Slow conduction, caused by fibrosis between surviving myocytes and connexin remodeling, is an important prerequisite for post-infarction ventricular tachycardia (VT); however, slow conduction is present throughout the infarct whereas VT circuits are finite in number and discrete. In a porcine model of VT, re-entrant circuits occur at region of significant repolarization heterogeneity caused by up-regulation of potassium channel β-subunits KCNE3 (increasing repolarization current) and KCNE4 (decreasing repolarization current), causing heterogeneous action potential durations. OBJECTIVES This study was designed to determine whether re-entrant circuits in human post-infarction VT are associated with repolarization heterogeneity. METHODS In 6 patients, left ventricular mapping was performed during induced VT to identify sites within the VT circuit. Subsequently, unipolar mapping (3.5-mm tip ablation catheter) was performed to characterize activation-recovery intervals (ARIs), which are surrogates for local action potential durations, at sites documented within the VT circuit isthmus (IN) compared to sites within the infarct scar but outside of the VT circuit (OUT). RESULTS ARIs were significantly shorter in the IN compared with the OUT sites (420.2 ± 79.3 ms vs 462 ± 52.8 ms; P = 0.01). In all patients. sites that were associated with the circuit always had shorter ARI values than did those sampled from OUT regions. CONCLUSIONS VT circuit sites in human post-infarct VT are associated with repolarization heterogeneity, similar to what was previously reported in a porcine model. This suggests the possibility of a common mechanism between humans and the porcine model of post-infarct VT, and that development of ablation strategies or small molecule or genetic therapies to restore normal repolarization kinetics may be antiarrhythmic.
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Affiliation(s)
- David J Callans
- Cardiac Electrophysiology Section, Cardiovascular Medicine Division, Department of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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23
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Yang HT, Li LL, Li SN, Wu JT, Chen K, Song WF, Zhang GB, Ma JF, Fu HX, Cao S, Gao CY, Hu J. MicroRNA-155 inhibition attenuates myocardial infarction-induced connexin 43 degradation in cardiomyocytes by reducing pro-inflammatory macrophage activation. Cardiovasc Diagn Ther 2022; 12:325-339. [PMID: 35800355 PMCID: PMC9253173 DOI: 10.21037/cdt-21-743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 06/01/2022] [Indexed: 09/29/2023]
Abstract
BACKGROUND Degradation of pro-inflammatory macrophage-mediated connexin 43 (Cx43) plays an important role in post-myocardial infarction (MI) arrhythmogenesis, microRNA (miR)-155 produced by macrophages has been shown to mediate post-MI effects. We hypothesized that miR-155 inhibition attenuated MI-induced Cx43 degradation by reducing pro-inflammatory macrophage activation. METHODS MI was induced by permanent ligation of the left anterior descending coronary artery in male C57BL/6 mice. Lipopolysaccharide (LPS)-stimulated mice bone marrow-derived macrophages (BMDMs) and hypoxia-induced neonatal rat cardiomyocytes (NRCMs) were used in vitro models. qRT-PCR, Western-blot and immunofluorescence were used to analyze relevant indicators. RESULTS The expression levels of miR-155, interleukin-1 beta (IL-1β), and matrix metalloproteinase (MMP)7 were higher in MI mice and LPS-treated BMDMs than in the sham/control groups, treatment with a miR-155 antagomir reversed these effects. Moreover, miR-155 inhibition reduced ventricular arrhythmias incidence and improved cardiac function in MI mice. Cx43 expression was decreased in MI mice and hypoxia-exposed NRCMs, and hypoxia-induced Cx43 degradation in NRCMs was reduced by application of conditioned medium from LPS-induced BMDMs treated with the miR-155 antagomir, but increased by conditioned medium from BMDMs treated with a miR-155 agomir. Importantly, NRCMs cultured in conditioned medium from LPS-induced BMDMs transfected with small interfering RNA against IL-1β and MMP7 showed decreased hypoxia-mediated Cx43 degradation, and this effect also was diminished by BMDM treatment with the miR-155 agomir. Additionally, siRNA-mediated suppressor of cytokine signaling 1 (SOCS1) knockdown in LPS-induced BMDMs promoted Cx43 degradation in hypoxia-exposed NRCMs, and the effect was reduced by the miR-155 inhibition. CONCLUSIONS MiR-155 inhibition attenuated post-MI Cx43 degradation by reducing macrophage-mediated IL-1β and MMP7 expression through the SOCS1/nuclear factor-κB pathway.
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Affiliation(s)
- Hai-Tao Yang
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Li-Li Li
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Song-Nan Li
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung and Blood Vessel Diseases, Beijing, China
| | - Jin-Tao Wu
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Ke Chen
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Wei-Feng Song
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Guo-Bao Zhang
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Ji-Fang Ma
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Hai-Xia Fu
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Sheng Cao
- Department of Ultrasound, Renmin Hospital of Wuhan University, Wuhan, China
| | - Chuan-Yu Gao
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
| | - Juan Hu
- Heart Center of Henan Provincial People’s Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China
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24
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Billur D, Olgar Y, Turan B. Intracellular Redistribution of Left Ventricular Connexin 43 Contributes to the Remodeling of Electrical Properties of the Heart in Insulin-resistant Elderly Rats. J Histochem Cytochem 2022; 70:447-462. [PMID: 35608408 DOI: 10.1369/00221554221101661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The correlation between long-QT and connexin 43 (Cx43) status and localization in elderly rats was determined to demonstrate a correlation between insulin resistance (I-R), ischemia-reperfusion, aging, and heart dysfunction. Male Wistar rats are grouped as 24-month-old rats (Aged-group), those with metabolic syndrome (8 months old; MetS-group), or controls (8 months old; Con-group). Both experimental groups have long-QT and low heart rate. Immunohistochemical imaging and quantification showed marked decreases in Cx43 staining of intercalated disc with less localizations in the Aged-group and MetS-group. The lateralization of Cx43 on longitudinal cell membrane was significantly high in the MetS-group than in the Con-group with no significant change in the Aged-group. Its significant cytoplasmic internalization was higher in the Aged-group than in the MetS-group. There were marked decreases in phospho-Cx43 (pCx43) staining of intercalated disc with less localizations in both groups than in the Con-group. Furthermore, lateralization of pCx43 was significantly low in the Aged-group and MetS-group, whereas there were no significant changes in the cytoplasmic internalization of both groups compared with the Con-group. Furthermore, the ratio of pCx43 to Cx43 was significantly small in both groups. We determined increases in RhoA and endothelin-1 in both groups, further supporting decreases in pCx43. Our data indicate the important role of I-R on long-QT in aging heart through alterations in both Cx43 protein level and localizations, leading to an abnormal spreading of ventricular repolarization in I-R heart.
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Affiliation(s)
| | | | - Belma Turan
- Department of Biophysics.,Faculty of Medicine, Ankara University, Ankara, Turkey, and Department of Biophysics, Faculty of Medicine, Lokman Hekim University, Ankara, Turkey
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25
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Jian K, Li C, Hancox JC, Zhang H. Pro-Arrhythmic Effects of Discontinuous Conduction at the Purkinje Fiber-Ventricle Junction Arising From Heart Failure-Induced Ionic Remodeling - Insights From Computational Modelling. Front Physiol 2022; 13:877428. [PMID: 35547576 PMCID: PMC9081695 DOI: 10.3389/fphys.2022.877428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/18/2022] [Indexed: 11/18/2022] Open
Abstract
Heart failure is associated with electrical remodeling of the electrical properties and kinetics of the ion channels and transporters that are responsible for cardiac action potentials. However, it is still unclear whether heart failure-induced ionic remodeling can affect the conduction of excitation waves at the Purkinje fiber-ventricle junction contributing to pro-arrhythmic effects of heart failure, as the complexity of the heart impedes a detailed experimental analysis. The aim of this study was to employ computational models to investigate the pro-arrhythmic effects of heart failure-induced ionic remodeling on the cardiac action potentials and excitation wave conduction at the Purkinje fiber-ventricle junction. Single cell models of canine Purkinje fiber and ventricular myocytes were developed for control and heart failure. These single cell models were then incorporated into one-dimensional strand and three-dimensional wedge models to investigate the effects of heart failure-induced remodeling on propagation of action potentials in Purkinje fiber and ventricular tissue and at the Purkinje fiber-ventricle junction. This revealed that heart failure-induced ionic remodeling of Purkinje fiber and ventricular tissue reduced conduction safety and increased tissue vulnerability to the genesis of the unidirectional conduction block. This was marked at the Purkinje fiber-ventricle junction, forming a potential substrate for the genesis of conduction failure that led to re-entry. This study provides new insights into proarrhythmic consequences of heart failure-induced ionic remodeling.
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Affiliation(s)
- Kun Jian
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Chen Li
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Jules C. Hancox
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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26
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Ueda Y, Asamoto M, Kariya T, Akai T, Hoshina K, Uchida K. Ventricular fibrillation during carotid endarterectomy and bailout stenting: a case report. JA Clin Rep 2022; 8:26. [PMID: 35357630 PMCID: PMC8971334 DOI: 10.1186/s40981-022-00517-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/19/2022] [Accepted: 03/22/2022] [Indexed: 11/10/2022] Open
Abstract
Background Carotid artery manipulation is not a special technique but reports of intraoperative ventricular fibrillation are rare. The risk of fatal arrhythmias may be hidden behind routine surgical techniques and anesthetic management. We focused on QT prolongation and QT dispersion. Case presentation A 77-year-old man underwent carotid endarterectomy and bailout stenting. Although there were no obvious preoperative risk factors for intraoperative ventricular tachyarrhythmia, ventricular fibrillation (VF) had occurred during a maneuver of the carotid artery under hypercapnia. QTc was prolonged from 317 ms before surgery to 458 ms before the onset of VF. QTc dispersion between leads II and III was also increased to 50 ms. Hypomagnesemia was noted after resuscitation by electrical defibrillation, adrenaline, and noradrenaline. Conclusions We considered that the combination of multiple risk factors led to the development of ventricular fibrillation. It should be noted that carotid artery manipulation has the potential to cause arrhythmias.
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27
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Gionti V, Scacchi S, Colli Franzone P, Pavarino LF, Dore R, Storti C. Role of Scar and Border Zone Geometry on the Genesis and Maintenance of Re-Entrant Ventricular Tachycardia in Patients With Previous Myocardial Infarction. Front Physiol 2022; 13:834747. [PMID: 35399271 PMCID: PMC8989182 DOI: 10.3389/fphys.2022.834747] [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: 12/13/2021] [Accepted: 02/21/2022] [Indexed: 11/23/2022] Open
Abstract
In patients with healed myocardial infarction, the left ventricular ejection fraction is characterized by low sensitivity and specificity in the prediction of future malignant arrhythmias. Thus, there is the need for new parameters in daily practice to perform arrhythmic risk stratification. The aim of this study is to identify some features of proarrhythmic geometric configurations of scars and border zones (BZ), by means of numerical simulations based on left ventricular models derived from post myocardial infarction patients. Two patients with similar clinical characteristics were included in this study. Both patients exhibited left ventricular scars characterized by subendo- and subepicardial BZ and a transmural BZ isthmus. The scar of patient #1 was significantly larger than that of patient #2, whereas the transmural BZ isthmus and the subdendo- and subepicardial BZs of patient #2 were thicker than those of patient #1. Patient #1 was positive at electrophysiologic testing, whereas patient #2 was negative. Based on the cardiac magnetic resonance (CMR) data, we developed a geometric model of the left ventricles of the two patients, taking into account the position, extent, and topological features of scars and BZ. The numerical simulations were based on the anisotropic monodomain model of electrocardiology. In the model of patient #1, sustained ventricular tachycardia (VT) was inducible by an S2 stimulus delivered at any of the six stimulation sites considered, while in the model of patient #2 we were not able to induce sustained VT. In the model of patient #1, making the subendo- and subepicardial BZs as thick as those of patient #2 did not affect the inducibility and maintenance of VT. On the other hand, in the model of patient #2, making the subendo- and subepicardial BZs as thin as those of patient #1 yielded sustained VT. In conclusion, the results show that the numerical simulations have an effective predictive capability in discriminating patients at high arrhythmic risk. The extent of the infarct scar and the presence of transmural BZ isthmuses and thin subendo- and subepicardial BZs promote sustained VT.
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Affiliation(s)
- Vincenzo Gionti
- Divisione di Cardiologia, Istituto di Cura Città di Pavia, Pavia, Italy
| | - Simone Scacchi
- Dipartimento di Matematica, Università degli Studi di Milano, Milan, Italy
- *Correspondence: Simone Scacchi
| | | | - Luca F. Pavarino
- Dipartimento di Matematica, Università degli Studi di Pavia, Pavia, Italy
| | - Roberto Dore
- Divisione di Cardiologia, Istituto di Cura Città di Pavia, Pavia, Italy
| | - Cesare Storti
- Divisione di Cardiologia, Istituto di Cura Città di Pavia, Pavia, Italy
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28
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Yang D, Deschênes I, Fu JD. Multilayer control of cardiac electrophysiology by microRNAs. J Mol Cell Cardiol 2022; 166:107-115. [PMID: 35247375 PMCID: PMC9035102 DOI: 10.1016/j.yjmcc.2022.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/22/2022] [Accepted: 02/26/2022] [Indexed: 10/18/2022]
Abstract
The electrophysiological properties of the heart include cardiac automaticity, excitation (i.e., depolarization and repolarization of action potential) of individual cardiomyocytes, and highly coordinated electrical propagation through the whole heart. An abnormality in any of these properties can cause arrhythmias. MicroRNAs (miRs) have been recognized as essential regulators of gene expression through the conventional RNA interference (RNAi) mechanism and are involved in a variety of biological events. Recent evidence has demonstrated that miRs regulate the electrophysiology of the heart through fine regulation by the conventional RNAi mechanism of the expression of ion channels, transporters, intracellular Ca2+-handling proteins, and other relevant factors. Recently, a direct interaction between miRs and ion channels has also been reported in the heart, revealing a biophysical modulation by miRs of cardiac electrophysiology. These advanced discoveries suggest that miR controls cardiac electrophysiology through two distinct mechanisms: immediate action through biophysical modulation and long-term conventional RNAi regulation. Here, we review the recent research progress and summarize the current understanding of how miR manipulates the function of ion channels to maintain the homeostasis of cardiac electrophysiology.
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Affiliation(s)
- Dandan Yang
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, 333 W. 10(th) Avenue, Columbus, OH 43210, USA
| | - Isabelle Deschênes
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, 333 W. 10(th) Avenue, Columbus, OH 43210, USA
| | - Ji-Dong Fu
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, 333 W. 10(th) Avenue, Columbus, OH 43210, USA.
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29
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Lou J, Chen H, Huang S, Chen P, Yu Y, Chen F. Update on risk factors and biomarkers of sudden unexplained cardiac death. J Forensic Leg Med 2022; 87:102332. [DOI: 10.1016/j.jflm.2022.102332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/21/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023]
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30
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Zhu C, Rajendran PS, Hanna P, Efimov IR, Salama G, Fowlkes CC, Shivkumar K. High-resolution structure-function mapping of intact hearts reveals altered sympathetic control of infarct border zones. JCI Insight 2022; 7:153913. [PMID: 35132963 PMCID: PMC8855798 DOI: 10.1172/jci.insight.153913] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Remodeling of injured sympathetic nerves on the heart after myocardial infarction (MI) contributes to adverse outcomes such as sudden arrhythmic death, yet the underlying structural mechanisms are poorly understood. We sought to examine microstructural changes on the heart after MI and to directly link these changes with electrical dysfunction. We developed a high-resolution pipeline for anatomically precise alignment of electrical maps with structural myofiber and nerve-fiber maps created by customized computer vision algorithms. Using this integrative approach in a mouse model, we identified distinct structure-function correlates to objectively delineate the infarct border zone, a known source of arrhythmias after MI. During tyramine-induced sympathetic nerve activation, we demonstrated regional patterns of altered electrical conduction aligned directly with altered neuroeffector junction distribution, pointing to potential neural substrates for cardiac arrhythmia. This study establishes a synergistic framework for examining structure-function relationships after MI with microscopic precision that has potential to advance understanding of arrhythmogenic mechanisms.
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Affiliation(s)
- Ching Zhu
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Pradeep S Rajendran
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Peter Hanna
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Guy Salama
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Charless C Fowlkes
- Department of Computer Science, University of California, Irvine, Irvine, California, USA
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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31
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Ciaccio EJ, Anter E, Coromilas J, Wan EY, Yarmohammadi H, Wit AL, Peters NS, Garan H. Structure and function of the ventricular tachycardia isthmus. Heart Rhythm 2022; 19:137-153. [PMID: 34371192 DOI: 10.1016/j.hrthm.2021.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/22/2021] [Accepted: 08/01/2021] [Indexed: 12/24/2022]
Abstract
Catheter ablation of postinfarction reentrant ventricular tachycardia (VT) has received renewed interest owing to the increased availability of high-resolution electroanatomic mapping systems that can describe the VT circuits in greater detail, and the emergence and need to target noninvasive external beam radioablation. These recent advancements provide optimism for improving the clinical outcome of VT ablation in patients with postinfarction and potentially other scar-related VTs. The combination of analyses gleaned from studies in swine and canine models of postinfarction reentrant VT, and in human studies, suggests the existence of common electroanatomic properties for reentrant VT circuits. Characterizing these properties may be useful for increasing the specificity of substrate mapping techniques and for noninvasive identification to guide ablation. Herein, we describe properties of reentrant VT circuits that may assist in elucidating the mechanisms of onset and maintenance, as well as a means to localize and delineate optimal catheter ablation targets.
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Affiliation(s)
- Edward J Ciaccio
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York; ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, United Kingdom.
| | - Elad Anter
- Department of Cardiovascular Medicine, Cardiac Electrophysiology, Cleveland Clinic, Cleveland, Ohio
| | - James Coromilas
- Department of Medicine, Division of Cardiovascular Disease and Hypertension, Rutgers University, New Brunswick, New Jersey
| | - Elaine Y Wan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York
| | - Hirad Yarmohammadi
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York
| | - Andrew L Wit
- Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, United Kingdom
| | - Hasan Garan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York
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32
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Huang Y, Ding HS, Song T, Chen YT, Wang T, Tang YH, Barajas-Martinez H, Huang CX, Hu D. Abrogation of CC Chemokine Receptor 9 Ameliorates Ventricular Electrical Remodeling in Mice After Myocardial Infarction. Front Cardiovasc Med 2021; 8:716219. [PMID: 34712704 PMCID: PMC8545906 DOI: 10.3389/fcvm.2021.716219] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/13/2021] [Indexed: 11/28/2022] Open
Abstract
Introduction: Myocardial infarction (MI) triggers structural and electrical remodeling. CC chemokine receptor 9 (CCR9) mediates chemotaxis of inflammatory cells in MI. In our previous study, CCR9 knockout has been found to improve structural remodeling after MI. Here, we further investigate the potential influence of CCR9 on electrical remodeling following MI in order to explore potential new measures to improve the prognosis of MI. Methods and Results: Mice was used and divided into four groups: CCR9+/+/Sham, CCR9−/−/Sham, CCR9+/+/MI, CCR9−/−/MI. Animals were used at 1 week after MI surgery. Cardiomyocytes in the infracted border zone were acutely dissociated and the whole-cell patch clamp was used to record action potential duration (APD), L-type calcium current (ICa,L) and transient outward potassium current (Ito). Calcium transient and sarcoplasmic reticulum (SR) calcium content under stimulation of Caffeine were measured in isolated cardiomyocytes by confocal microscopy. Multielectrode array (MEA) was used to measure the conduction of the left ventricle. The western-blot was performed for the expression level of connexin 43. We observed prolonged APD90, increased ICa,L and decreased Ito following MI, while CCR9 knockout attenuated these changes (APD90: 50.57 ± 6.51 ms in CCR9−/−/MI vs. 76.53 ± 5.98 ms in CCR9+/+/MI, p < 0.05; ICa,L: −13.15 ± 0.86 pA/pF in CCR9−/−/MI group vs. −17.05 ± 1.11 pA/pF in CCR9+/+/MI, p < 0.05; Ito: 4.01 ± 0.17 pA/pF in CCR9−/−/MI group vs. 2.71 ± 0.16 pA/pF in CCR9+/+/MI, p < 0.05). The confocal microscopy results revealed CCR9 knockout reversed the calcium transient and calcium content reduction in sarcoplasmic reticulum following MI. MEA measurements showed improved conduction velocity in CCR9−/−/MI mice (290.1 ± 34.47 cm/s in CCR9−/−/MI group vs. 113.2 ± 14.4 cm/s in CCR9+/+/MI group, p < 0.05). Western-blot results suggested connexin 43 expression was lowered after MI while CCR9 knockout improved its expression. Conclusion: This study shows CCR9 knockout prevents the electrical remodeling by normalizing ion currents, the calcium homeostasis, and the gap junction to maintain APD and the conduction function. It suggests CCR9 is a promising therapeutic target for MI-induced arrhythmia, which warrants further investigation.
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Affiliation(s)
- Yan Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Hua-Sheng Ding
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Tao Song
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Yu-Ting Chen
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
| | - Teng Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
| | - Yan-Hong Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Hector Barajas-Martinez
- Lankenau Institute for Medical Research, Lankenau Heart Institute, Wynnwood, PA, United States.,Jefferson Medical College, Philadelphia, PA, United States
| | - Cong-Xin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Dan Hu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
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33
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Nowak MB, Veeraraghavan R, Poelzing S, Weinberg SH. Cellular Size, Gap Junctions, and Sodium Channel Properties Govern Developmental Changes in Cardiac Conduction. Front Physiol 2021; 12:731025. [PMID: 34759834 PMCID: PMC8573326 DOI: 10.3389/fphys.2021.731025] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/28/2021] [Indexed: 11/26/2022] Open
Abstract
Electrical conduction in cardiac ventricular tissue is regulated via sodium (Na+) channels and gap junctions (GJs). We and others have recently shown that Na+channels preferentially localize at the site of cell-cell junctions, the intercalated disc (ID), in adult cardiac tissue, facilitating coupling via the formation of intercellular Na+nanodomains, also termed ephaptic coupling (EpC). Several properties governing EpC vary with age, including Na+channel and GJ expression and distribution and cell size. Prior work has shown that neonatal cardiomyocytes have immature IDs with Na+channels and GJs diffusively distributed throughout the sarcolemma, while adult cells have mature IDs with preferentially localized Na+channels and GJs. In this study, we perform an in silico investigation of key age-dependent properties to determine developmental regulation of cardiac conduction. Simulations predict that conduction velocity (CV) biphasically depends on cell size, depending on the strength of GJ coupling. Total cell Na+channel conductance is predictive of CV in cardiac tissue with high GJ coupling, but not correlated with CV for low GJ coupling. We find that ephaptic effects are greatest for larger cells with low GJ coupling typically associated with intermediate developmental stages. Finally, simulations illustrate how variability in cellular properties during different developmental stages can result in a range of possible CV values, with a narrow range for both neonatal and adult myocardium but a much wider range for an intermediate developmental stage. Thus, we find that developmental changes predict associated changes in cardiac conduction.
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Affiliation(s)
- Madison B. Nowak
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- The Ohio State University Wexner Medical Center, Davis Heart and Lung Research Institute, Columbus, OH, United States
| | - Steven Poelzing
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
- Virginia Polytechnic Institute and State University, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - Seth H. Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- The Ohio State University Wexner Medical Center, Davis Heart and Lung Research Institute, Columbus, OH, United States
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34
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Pourtaji A, Sahebkar A, Poorzand H, Moshiri M, Mohammadpour AH, Mousavi SR. Evaluation of the Cardioprotective Effect of Granulocyte Colony Stimulating Factor in Patients with Carbon Monoxide Poisoning. Protein Pept Lett 2021; 28:589-601. [PMID: 33092501 DOI: 10.2174/0929866527666201022112810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Carbon monoxide (CO), which is well known as silent killer, has many toxic effects on organs with high rate of metabolism such as heart and brain. CO-induced cardiotoxicity resulted in a wide range of disabilities including electrocardiogram (ECG) abnormalities, elevation in level of cardiac enzymes, arrhythmias, impairment of left ventricular and myocardial infarction (MI). Cardio-protective effects of Granulocyte colony-stimulating factor (G-CSF) on infarcted heart was proved previously in various reports. OBJECTIVE In this study, possible effect of G-CSF on cardiac function of patients with moderate to severe acute CO poisoning was investigated. METHODS Cardioprotective effects of G-CSF in CO-poisoned patients was evaluated through ECG, Holter monitoring, echocardiography, and biochemical studies. Continuous intravenous infusion of G-CSF (90 μg/kg) and normal saline were administered respectively to treatment and placebo groups. RESULTS The results demonstrated that in moderate to severe CO poisoning, myocardial injury is common. ECG changes (e.g., ST-segment and T-wave changes, QTC), cardiac arrhythmias (e.g., heart blocks and ventricular arrhythmias), serum level of Troponin I, left ventricular ejection fraction were determined after G-CSF administration. Frequencies of ST depression, inversion or flatting of T wave and QTC in ECG were significantly reduced after G-CSF treatment. In addition, incidence of cardiac arrhythmias due to CO poisoning were reduced after G-CSF treatment. However, G-CSF did not exert protective effects on TPI level and function of left ventricular in CO-poisoned patients. CONCLUSION GCSF could probably reduce CO-induced cardiac ischemia in patients with acute CO poisoning. CLINICAL TRIAL REGISTRATION The trial protocol was registered in the Iranian Registry of Clinical Trials (http://www.irct.ir) registry (Irct ID: IRCT201607232083N7).
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Affiliation(s)
- Atena Pourtaji
- Pharmaceutical Research Center, Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hoorak Poorzand
- Atherosclerosis Prevention Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Moshiri
- Medical Toxicology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Hooshang Mohammadpour
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Reza Mousavi
- Medical Toxicology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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35
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Davis J, Chouman A, Creech J, Monteiro da Rocha A, Ponce-Balbuena D, Jimenez Vazquez EN, Nichols R, Lozhkin A, Madamanchi NR, Campbell KF, Herron TJ. In vitro model of ischemic heart failure using human induced pluripotent stem cell-derived cardiomyocytes. JCI Insight 2021; 6:134368. [PMID: 33878037 PMCID: PMC8262347 DOI: 10.1172/jci.insight.134368] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 04/15/2021] [Indexed: 11/17/2022] Open
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been used extensively to model inherited heart diseases, but hiPSC-CM models of ischemic heart disease are lacking. Here, our objective was to generate an hiPSC-CM model of ischemic heart disease. To this end, hiPSCs were differentiated into functional hiPSC-CMs and then purified using either a simulated ischemia media or by using magnetic antibody-based purification targeting the nonmyocyte population for depletion from the cell population. Flow cytometry analysis confirmed that each purification approach generated hiPSC-CM cultures that had more than 94% cTnT+ cells. After purification, hiPSC-CMs were replated as confluent syncytial monolayers for electrophysiological phenotype analysis and protein expression by Western blotting. The phenotype of metabolic stress-selected hiPSC-CM monolayers recapitulated many of the functional and structural hallmarks of ischemic CMs, including elevated diastolic calcium, diminished calcium transient amplitude, prolonged action potential duration, depolarized resting membrane potential, hypersensitivity to chemotherapy-induced cardiotoxicity, depolarized mitochondrial membrane potential, depressed SERCA2a expression, reduced maximal oxygen consumption rate, and abnormal response to β1-adrenergic receptor stimulation. These findings indicate that metabolic selection of hiPSC-CMs generated cell populations with phenotype similar to what is well known to occur in the setting of ischemic heart failure and thus provide a opportunity for study of human ischemic heart disease.
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Affiliation(s)
- Justin Davis
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine
| | - Ahmad Chouman
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine
| | - Jeffery Creech
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine
| | - Andre Monteiro da Rocha
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine.,Center for Arrhythmia Research.,Department of Internal Medicine, Division of Cardiovascular Medicine
| | | | | | | | - Andrey Lozhkin
- Department of Internal Medicine, Division of Cardiovascular Medicine
| | | | - Katherine F Campbell
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine.,Center for Arrhythmia Research
| | - Todd J Herron
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine.,Center for Arrhythmia Research.,Department of Internal Medicine, Division of Cardiovascular Medicine.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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36
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Marsh SR, Williams ZJ, Pridham KJ, Gourdie RG. Peptidic Connexin43 Therapeutics in Cardiac Reparative Medicine. J Cardiovasc Dev Dis 2021; 8:52. [PMID: 34063001 PMCID: PMC8147937 DOI: 10.3390/jcdd8050052] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/19/2021] [Accepted: 05/01/2021] [Indexed: 12/12/2022] Open
Abstract
Connexin (Cx43)-formed channels have been linked to cardiac arrhythmias and diseases of the heart associated with myocardial tissue loss and fibrosis. These pathologies include ischemic heart disease, ischemia-reperfusion injury, heart failure, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and Duchenne muscular dystrophy. A number of Cx43 mimetic peptides have been reported as therapeutic candidates for targeting disease processes linked to Cx43, including some that have advanced to clinical testing in humans. These peptides include Cx43 sequences based on the extracellular loop domains (e.g., Gap26, Gap 27, and Peptide5), cytoplasmic-loop domain (Gap19 and L2), and cytoplasmic carboxyl-terminal domain (e.g., JM2, Cx43tat, CycliCX, and the alphaCT family of peptides) of this transmembrane protein. Additionally, RYYN peptides binding to the Cx43 carboxyl-terminus have been described. In this review, we survey preclinical and clinical data available on short mimetic peptides based on, or directly targeting, Cx43, with focus on their potential for treating heart disease. We also discuss problems that have caused reluctance within the pharmaceutical industry to translate peptidic therapeutics to the clinic, even when supporting preclinical data is strong. These issues include those associated with the administration, stability in vivo, and tissue penetration of peptide-based therapeutics. Finally, we discuss novel drug delivery technologies including nanoparticles, exosomes, and other nanovesicular carriers that could transform the clinical and commercial viability of Cx43-targeting peptides in treatment of heart disease, stroke, cancer, and other indications requiring oral or parenteral administration. Some of these newly emerging approaches to drug delivery may provide a path to overcoming pitfalls associated with the drugging of peptide therapeutics.
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Affiliation(s)
- Spencer R. Marsh
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
| | - Zachary J. Williams
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
- Translational Biology Medicine and Health Graduate Program, Virginia Tech, Roanoke, VA 24016, USA
| | - Kevin J. Pridham
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
| | - Robert G. Gourdie
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
- Translational Biology Medicine and Health Graduate Program, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA
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37
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Mahajan R, Lau DH, Brooks AG, Shipp NJ, Wood JPM, Manavis J, Samuel CS, Patel KP, Finnie JW, Alasady M, Kalman JM, Sanders P. Atrial Fibrillation and Obesity: Reverse Remodeling of Atrial Substrate With Weight Reduction. JACC Clin Electrophysiol 2021; 7:630-641. [PMID: 33640353 DOI: 10.1016/j.jacep.2020.11.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 11/18/2022]
Abstract
OBJECTIVES This study sought to evaluate the effect of weight loss on the atrial substrate for atrial fibrillation (AF). BACKGROUND Whether weight loss can reverse the atrial substrate of obesity is not known. METHODS Thirty sheep had sustained obesity induced by ad libitum calorie-dense diet over 72 weeks. Animals were randomized to 3 groups: sustained obesity and 15% and 30% weight loss. The animals randomized to weight loss underwent weight reduction by reducing the quantity of hay over 32 weeks. Eight lean animals served as controls. All were subjected to the following: dual-energy x-ray absorptiometry, echocardiogram, cardiac magnetic resonance, electrophysiological study, and histological and molecular analyses (fatty infiltration, fibrosis, transforming growth factor β1, and connexin 43). RESULTS Sustained obesity was associated with increased left atrium (LA) pressure (p < 0.001), inflammation (p < 0.001), atrial transforming growth factor β1 protein (p < 0.001), endothelin-B receptor expression (p = 0.04), atrial fibrosis (p = 0.01), epicardial fat infiltration (p < 0.001), electrophysiological abnormalities, and AF burden (p = 0.04). Connexin 43 expression was decreased in the obese group (p = 0.03). In this obese ovine model, 30% weight reduction was associated with reduction in total body fat (p < 0.001), LA pressure (p = 0.007), inflammation (p < 0.001), endothelin-B receptor expression (p = 0.01), atrial fibrosis (p = 0.01), increase in atrial effective refractory period (cycle length: 400 and 300 ms; p < 0.001), improved conduction velocity (cycle length: 400 and 300 ms; p = 0.01), decreased conduction heterogeneity (p < 0.001), and decreased AF inducibility (p = 0.03). Weight loss was associated with a nonsignificant reduction in epicardial fat infiltration in posterior LA (p = 0.34). CONCLUSIONS Weight loss in an obese ovine model is associated with structural and electrophysiological reverse remodeling and a reduced propensity for AF. This provides evidence for the direct role of obesity in AF substrate and the role of weight reduction in patients with AF.
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Affiliation(s)
- Rajiv Mahajan
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, Australia; Department of Cardiology, Lyell McEwin Hospital, Adelaide, Australia
| | - Dennis H Lau
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, Australia; Department of Cardiology, Royal Adelaide Hospital, Adelaide, Australia
| | - Anthony G Brooks
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, Australia
| | - Nicholas J Shipp
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, Australia
| | - John P M Wood
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide; SA Pathology, Adelaide, Australia
| | - Jim Manavis
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide; SA Pathology, Adelaide, Australia
| | - Chrishan S Samuel
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Melbourne, Australia
| | - Krupesh P Patel
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Melbourne, Australia
| | - John W Finnie
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide; SA Pathology, Adelaide, Australia
| | - Muayad Alasady
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, Australia; Department of Cardiology, Royal Adelaide Hospital, Adelaide, Australia
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital and University of Melbourne, Melbourne, Australia
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, Australia; Department of Cardiology, Royal Adelaide Hospital, Adelaide, Australia.
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38
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Connexins in the Heart: Regulation, Function and Involvement in Cardiac Disease. Int J Mol Sci 2021; 22:ijms22094413. [PMID: 33922534 PMCID: PMC8122935 DOI: 10.3390/ijms22094413] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/20/2021] [Indexed: 12/20/2022] Open
Abstract
Connexins are a family of transmembrane proteins that play a key role in cardiac physiology. Gap junctional channels put into contact the cytoplasms of connected cardiomyocytes, allowing the existence of electrical coupling. However, in addition to this fundamental role, connexins are also involved in cardiomyocyte death and survival. Thus, chemical coupling through gap junctions plays a key role in the spreading of injury between connected cells. Moreover, in addition to their involvement in cell-to-cell communication, mounting evidence indicates that connexins have additional gap junction-independent functions. Opening of unopposed hemichannels, located at the lateral surface of cardiomyocytes, may compromise cell homeostasis and may be involved in ischemia/reperfusion injury. In addition, connexins located at non-canonical cell structures, including mitochondria and the nucleus, have been demonstrated to be involved in cardioprotection and in regulation of cell growth and differentiation. In this review, we will provide, first, an overview on connexin biology, including their synthesis and degradation, their regulation and their interactions. Then, we will conduct an in-depth examination of the role of connexins in cardiac pathophysiology, including new findings regarding their involvement in myocardial ischemia/reperfusion injury, cardiac fibrosis, gene transcription or signaling regulation.
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39
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Chowdhury RA, Debney MT, Protti A, Handa BS, Patel KHK, Lyon AR, Shah AM, Ng FS, Peters NS. Rotigaptide Infusion for the First 7 Days After Myocardial Infarction-Reperfusion Reduced Late Complexity of Myocardial Architecture of the Healing Border-Zone and Arrhythmia Inducibility. J Am Heart Assoc 2021; 10:e020006. [PMID: 33870715 PMCID: PMC8200720 DOI: 10.1161/jaha.120.020006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background Survivors of myocardial infarction are at increased risk of late ventricular arrhythmias, with infarct size and scar heterogeneity being key determinants of arrhythmic risk. Gap junctions facilitate the passage of small ions and morphogenic cell signaling between myocytes. We hypothesized that gap junctions enhancement during infarction–reperfusion modulates structural and electrophysiological remodeling and reduces late arrhythmogenesis. Methods and Results Infarction–reperfusion surgery was carried out in male Sprague‐Dawley rats followed by 7 days of rotigaptide or saline administration. The in vivo and ex vivo arrhythmogenicity was characterized by programmed electrical stimulation 3 weeks later, followed by diffusion‐weighted magnetic resonance imaging and Masson's trichrome histology. Three weeks after 7‐day postinfarction administration of rotigaptide, ventricular tachycardia/ventricular fibrillation was induced on programmed electrical stimulation in 20% and 53% of rats, respectively (rotigaptide versus control), resulting in reduction of arrhythmia score (3.2 versus 1.4, P=0.018), associated with the reduced magnetic resonance imaging parameters fractional anisotropy (fractional anisotropy: −5% versus −15%; P=0.062) and mean diffusivity (mean diffusivity: 2% versus 6%, P=0.042), and remodeling of the 3‐dimensional laminar structure of the infarct border zone with reduction of the mean (16° versus 19°, P=0.013) and the dispersion (9° versus 12°, P=0.015) of the myofiber transverse angle. There was no change in ECG features, spontaneous arrhythmias, or mortality. Conclusions Enhancement of gap junctions function by rotigaptide administered during the early healing phase in reperfused infarction reduces later complexity of infarct scar morphology and programmed electrical stimulation–induced arrhythmias, and merits further exploration as a feasible and practicable intervention in the acute myocardial infarction management to reduce late arrhythmic risk.
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Affiliation(s)
- Rasheda A Chowdhury
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
| | - Michael T Debney
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
| | - Andrea Protti
- King's British Heart Foundation Centre School of Cardiovascular Medicine and Sciences Kings College London London United Kingdom
| | - Balvinder S Handa
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
| | - Kiran H K Patel
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
| | - Alexander R Lyon
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
| | - Ajay M Shah
- King's British Heart Foundation Centre School of Cardiovascular Medicine and Sciences Kings College London London United Kingdom
| | - Fu Siong Ng
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
| | - Nicholas S Peters
- National Heart & Lung Institute and ElectroCardioMaths Programme of the Imperial Centre for Cardiac EngineeringImperial College London London United Kingdom
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Handa BS, Li X, Baxan N, Roney CH, Shchendrygina A, Mansfield CA, Jabbour RJ, Pitcher DS, Chowdhury RA, Peters NS, Ng FS. Ventricular fibrillation mechanism and global fibrillatory organization are determined by gap junction coupling and fibrosis pattern. Cardiovasc Res 2021; 117:1078-1090. [PMID: 32402067 PMCID: PMC7983010 DOI: 10.1093/cvr/cvaa141] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/25/2020] [Accepted: 05/21/2020] [Indexed: 11/13/2022] Open
Abstract
AIMS Conflicting data exist supporting differing mechanisms for sustaining ventricular fibrillation (VF), ranging from disorganized multiple-wavelet activation to organized rotational activities (RAs). Abnormal gap junction (GJ) coupling and fibrosis are important in initiation and maintenance of VF. We investigated whether differing ventricular fibrosis patterns and the degree of GJ coupling affected the underlying VF mechanism. METHODS AND RESULTS Optical mapping of 65 Langendorff-perfused rat hearts was performed to study VF mechanisms in control hearts with acute GJ modulation, and separately in three differing chronic ventricular fibrosis models; compact fibrosis (CF), diffuse fibrosis (DiF), and patchy fibrosis (PF). VF dynamics were quantified with phase mapping and frequency dominance index (FDI) analysis, a power ratio of the highest amplitude dominant frequency in the cardiac frequency spectrum. Enhanced GJ coupling with rotigaptide (n = 10) progressively organized fibrillation in a concentration-dependent manner; increasing FDI (0 nM: 0.53 ± 0.04, 80 nM: 0.78 ± 0.03, P < 0.001), increasing RA-sustained VF time (0 nM: 44 ± 6%, 80 nM: 94 ± 2%, P < 0.001), and stabilized RAs (maximum rotations for an RA; 0 nM: 5.4 ± 0.5, 80 nM: 48.2 ± 12.3, P < 0.001). GJ uncoupling with carbenoxolone progressively disorganized VF; the FDI decreased (0 µM: 0.60 ± 0.05, 50 µM: 0.17 ± 0.03, P < 0.001) and RA-sustained VF time decreased (0 µM: 61 ± 9%, 50 µM: 3 ± 2%, P < 0.001). In CF, VF activity was disorganized and the RA-sustained VF time was the lowest (CF: 27 ± 7% vs. PF: 75 ± 5%, P < 0.001). Global fibrillatory organization measured by FDI was highest in PF (PF: 0.67 ± 0.05 vs. CF: 0.33 ± 0.03, P < 0.001). PF harboured the longest duration and most spatially stable RAs (patchy: 1411 ± 266 ms vs. compact: 354 ± 38 ms, P < 0.001). DiF (n = 11) exhibited an intermediately organized VF pattern, sustained by a combination of multiple-wavelets and short-lived RAs. CONCLUSION The degree of GJ coupling and pattern of fibrosis influences the mechanism sustaining VF. There is a continuous spectrum of organization in VF, ranging between globally organized fibrillation sustained by stable RAs and disorganized, possibly multiple-wavelet driven fibrillation with no RAs.
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Affiliation(s)
- Balvinder S Handa
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Xinyang Li
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Nicoleta Baxan
- Biological Imaging Centre, Department of Medicine, Imperial College London, London, UK
| | - Caroline H Roney
- Division of Imaging Sciences and Bioengineering, King’s College London, London, UK
| | - Anastasia Shchendrygina
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Catherine A Mansfield
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Richard J Jabbour
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - David S Pitcher
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Rasheda A Chowdhury
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Nicholas S Peters
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
| | - Fu Siong Ng
- National Heart & Lung Institute, Imperial College London, 4th Floor, ICTEM Building, 72 Du Cane Road, London W12 0NN, UK
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MD1 Depletion Predisposes to Ventricular Arrhythmias in the Setting of Myocardial Infarction. Heart Lung Circ 2020; 30:869-881. [PMID: 33257269 DOI: 10.1016/j.hlc.2020.09.938] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 11/23/2022]
Abstract
BACKGROUND Myeloid differentiation protein 1 (MD1) is expressed in the human heart and is a negative regulator of Toll-like receptor 4 (TLR4) signalling. MD1 exerts anti-arrhythmic effects. AIM The aim of this study was to determine the role of MD1 in myocardial infarction (MI)-related ventricular arrhythmias (VAs). METHOD Myocardial infarction was induced by surgical ligation of the left anterior coronary artery in MD1 knockout (KO) mice and their wild-type littermates. Myocardial infarction-induced vulnerability to VAs and its underlying mechanisms were evaluated. RESULTS Myeloid differentiation protein 1 was downregulated in the MI mice. Myeloid differentiation protein 1 deficiency decreased post-MI left ventricular (LV) function and increased the infarct size. The MI mice exhibited prolonged action potential duration (APD), enhanced APD alternans thresholds, and a higher incidence of VAs. Myocardial infarction-induced LV fibrosis and inflammation decreased the expression levels of Kv4.2, Kv4.3, Kv1.5, and Kv2.1, increased Cav1.2 expression, and disturbed Ca2+ handling protein expression. These MI-induced adverse effects were further exacerbated in KO mice. Mechanistically, MD1 deletion markedly enhanced the activation of the TLR4/calmodulin-dependent protein kinase II (CaMKII) signalling pathway in post-MI mice. CONCLUSIONS Myeloid differentiation protein 1 deletion increases the vulnerability to VAs in post-MI mice. This is mainly caused by the aggravated maladaptive LV fibrosis and inflammation and interference with the expressions of ion channels and Ca2+ handling proteins, which is related to enhanced activation of the TLR4/CaMKII signalling pathway.
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Kotadia I, Whitaker J, Roney C, Niederer S, O’Neill M, Bishop M, Wright M. Anisotropic Cardiac Conduction. Arrhythm Electrophysiol Rev 2020; 9:202-210. [PMID: 33437488 PMCID: PMC7788398 DOI: 10.15420/aer.2020.04] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 10/09/2020] [Indexed: 01/06/2023] Open
Abstract
Anisotropy is the property of directional dependence. In cardiac tissue, conduction velocity is anisotropic and its orientation is determined by myocyte direction. Cell shape and size, excitability, myocardial fibrosis, gap junction distribution and function are all considered to contribute to anisotropic conduction. In disease states, anisotropic conduction may be enhanced, and is implicated, in the genesis of pathological arrhythmias. The principal mechanism responsible for enhanced anisotropy in disease remains uncertain. Possible contributors include changes in cellular excitability, changes in gap junction distribution or function and cellular uncoupling through interstitial fibrosis. It has recently been demonstrated that myocyte orientation may be identified using diffusion tensor magnetic resonance imaging in explanted hearts, and multisite pacing protocols have been proposed to estimate myocyte orientation and anisotropic conduction in vivo. These tools have the potential to contribute to the understanding of the role of myocyte disarray and anisotropic conduction in arrhythmic states.
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Affiliation(s)
- Irum Kotadia
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Caroline Roney
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
| | - Steven Niederer
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
| | - Mark O’Neill
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Martin Bishop
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
| | - Matthew Wright
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
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Sayers JR, Riley PR. Heart regeneration: beyond new muscle and vessels. Cardiovasc Res 2020; 117:727-742. [PMID: 33241843 DOI: 10.1093/cvr/cvaa320] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/16/2020] [Accepted: 10/28/2020] [Indexed: 02/06/2023] Open
Abstract
The most striking consequence of a heart attack is the loss of billions of heart muscle cells, alongside damage to the associated vasculature. The lost cardiovascular tissue is replaced by scar formation, which is non-functional and results in pathological remodelling of the heart and ultimately heart failure. It is, therefore, unsurprising that the heart regeneration field has centred efforts to generate new muscle and blood vessels through targeting cardiomyocyte proliferation and angiogenesis following injury. However, combined insights from embryological studies and regenerative models, alongside the adoption of -omics technology, highlight the extensive heterogeneity of cell types within the forming or re-forming heart and the significant crosstalk arising from non-muscle and non-vessel cells. In this review, we focus on the roles of fibroblasts, immune, conduction system, and nervous system cell populations during heart development and we consider the latest evidence supporting a function for these diverse lineages in contributing to regeneration following heart injury. We suggest that the emerging picture of neurologically, immunologically, and electrically coupled cell function calls for a wider-ranging combinatorial approach to heart regeneration.
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Affiliation(s)
- Judy R Sayers
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Oxbridge Centre of Regenerative Medicine, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, UK
| | - Paul R Riley
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Oxbridge Centre of Regenerative Medicine, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, UK
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Ciaccio EJ, Coromilas J, Wan EY, Yarmohammadi H, Saluja DS, Biviano AB, Wit AL, Peters NS, Garan H. Slow uniform electrical activation during sinus rhythm is an indicator of reentrant VT isthmus location and orientation in an experimental model of myocardial infarction. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 196:105666. [PMID: 32717622 DOI: 10.1016/j.cmpb.2020.105666] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/12/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND To validate the predictability of reentrant circuit isthmus locations without ventricular tachycardia (VT) induction during high-definition mapping, we used computer methods to analyse sinus rhythm activation in experiments where isthmus location was subsequently verified by mapping reentrant VT circuits. METHOD In 21 experiments using a canine postinfarction model, bipolar electrograms were obtained from 196-312 recordings with 4mm spacing in the epicardial border zone during sinus rhythm and during VT. From computerized electrical activation maps of the reentrant circuit, areas of conduction block were determined and the isthmus was localized. A linear regression was computed at three different locations about the reentry isthmus using sinus rhythm electrogram activation data. From the regression analysis, the uniformity, a measure of the constancy at which the wavefront propagates, and the activation gradient, a measure that may approximate wavefront speed, were computed. The purpose was to test the hypothesis that the isthmus locates in a region of slow uniform activation bounded by areas of electrical discontinuity. RESULTS Based on the regression parameters, sinus rhythm activation along the isthmus near its exit proceeded uniformly (mean r2= 0.95±0.05) and with a low magnitude gradient (mean 0.37±0.10mm/ms). Perpendicular to the isthmus long-axis across its boundaries, the activation wavefront propagated much less uniformly (mean r2= 0.76±0.24) although of similar gradient (mean 0.38±0.23mm/ms). In the opposite direction from the exit, at the isthmus entrance, there was also less uniformity (mean r2= 0.80±0.22) but a larger magnitude gradient (mean 0.50±0.25mm/ms). A theoretical ablation line drawn perpendicular to the last sinus rhythm activation site along the isthmus long-axis was predicted to prevent VT reinduction. Anatomical conduction block occurred in 7/21 experiments, but comprised only small portions of the isthmus lateral boundaries; thus detection of sinus rhythm conduction block alone was insufficient to entirely define the VT isthmus. CONCLUSIONS Uniform activation with a low magnitude gradient during sinus rhythm is present at the VT isthmus exit location but there is less uniformity across the isthmus lateral boundaries and at isthmus entrance locations. These factors may be useful to verify any proposed VT isthmus location, reducing the need for VT induction to ablate the isthmus. Measured computerized values similar to those determined herein could therefore be assistive to sharpen specificity when applying sinus rhythm mapping to localize EP catheter ablation sites.
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Affiliation(s)
- Edward J Ciaccio
- Department of Medicine - Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK.
| | - James Coromilas
- Department of Medicine - Division of Cardiovascular Disease and Hypertension, Rutgers University, New Brunswick, NJ, USA
| | - Elaine Y Wan
- Department of Medicine - Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Hirad Yarmohammadi
- Department of Medicine - Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Deepak S Saluja
- Department of Medicine - Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Angelo B Biviano
- Department of Medicine - Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Andrew L Wit
- Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Hasan Garan
- Department of Medicine - Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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Zheng L, Trease AJ, Katsurada K, Spagnol G, Li H, Shi W, Duan B, Patel KP, Sorgen PL. Inhibition of Pyk2 and Src activity improves Cx43 gap junction intercellular communication. J Mol Cell Cardiol 2020; 149:27-40. [PMID: 32956670 DOI: 10.1016/j.yjmcc.2020.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 11/24/2022]
Abstract
Identification of proteins that interact with Cx43 has been instrumental in the understanding of gap junction (GJ) regulation. An in vitro phosphorylation screen identified that Protein tyrosine kinase 2 beta (Pyk2) phosphorylated purified Cx43CT and this led us to characterize the impact of this phosphorylation on Cx43 function. Mass spectrometry identified Pyk2 phosphorylates Cx43 residues Y247, Y265, Y267, and Y313. Western blot and immunofluorescence staining using HeLaCx43 cells, HEK 293 T cells, and neonatal rat ventricular myocytes (NRVMs) revealed Pyk2 can be activated by Src and active Pyk2 interacts with Cx43 at the plasma membrane. Overexpression of Pyk2 increases Cx43 phosphorylation and knock-down of Pyk2 decreases Cx43 phosphorylation, without affecting the level of active Src. In HeLaCx43 cells treated with PMA to activate Pyk2, a decrease in Cx43 GJ intercellular communication (GJIC) was observed when assayed by dye transfer. Moreover, PMA activation of Pyk2 could be inhibited by the small molecule PF4618433. This partially restored GJIC, and when paired with a Src inhibitor, returned GJIC to the no PMA control-level. The ability of Pyk2 and Src inhibitors to restore Cx43 function in the presence of PMA was also observed in NRVMs. Additionally, an animal model of myocardial infarction induced heart failure showed a higher level of active Pyk2 activity and increased interaction with Cx43 in ventricular myocytes. Src inhibitors have been used to reverse Cx43 remodeling and improve heart function after myocardial infarction; however, they alone could not fully restore proper Cx43 function. Our data suggest that Pyk2 may need to be inhibited, in addition to Src, to further (if not completely) reverse Cx43 remodeling and improve intercellular communication.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kenichi Katsurada
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Wen Shi
- Division of Cardiology, Department of Internal Medicine/Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bin Duan
- Division of Cardiology, Department of Internal Medicine/Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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Dynamic UTR Usage Regulates Alternative Translation to Modulate Gap Junction Formation during Stress and Aging. Cell Rep 2020; 27:2737-2747.e5. [PMID: 31141695 PMCID: PMC6857847 DOI: 10.1016/j.celrep.2019.04.114] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/20/2019] [Accepted: 04/29/2019] [Indexed: 11/22/2022] Open
Abstract
Connexin43 (Cx43; gene name GJA1) is the most ubiquitously expressed gap junction protein, and understanding of its regulation largely falls under transcription and post-translational modification. In addition to Cx43, Gja1 mRNA encodes internally translated isoforms regulating gap junction formation, whose expression is modulated by TGF-β. Here, using RLM-RACE, we identify distinct Gja1 transcripts differing only in 5′ UTR length, of which two are upregulated during TGF-β exposure and hypoxia. Introduction of these transcripts into Gja1−/− cells phenocopies the response of Gja1 to TGF-β with reduced internal translation initiation. Inhibiting pathways downstream of TGF-β selectively regulates levels of Gja1 transcript isoforms and translation products. Reporter assays reveal enhanced translation of full-length Cx43 from shorter Gja1 5′ UTR isoforms. We also observe a correlation among UTR selection, translation, and reduced gap junction formation in aged heart tissue. These data elucidate a relationship between transcript isoform expression and translation initiation regulating intercellular communication. Connexin43 gap junctions enable direct intercellular communication facilitating action potential propagation. Internal translation of connexin43 mRNA generates the truncated isoform GJA1–20k, which promotes gap junction formation. During aging, Zeitz et al. find that activation of stress-response pathways shortens connexin43 mRNA UTRs to limit GJA1–20k translation coincident with gap junction loss.
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Translating Translation to Mechanisms of Cardiac Hypertrophy. J Cardiovasc Dev Dis 2020; 7:jcdd7010009. [PMID: 32164190 PMCID: PMC7151157 DOI: 10.3390/jcdd7010009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/18/2022] Open
Abstract
Cardiac hypertrophy in response to chronic pathological stress is a common feature occurring with many forms of heart disease. This pathological hypertrophic growth increases the risk for arrhythmias and subsequent heart failure. While several factors promoting cardiac hypertrophy are known, the molecular mechanisms governing the progression to heart failure are incompletely understood. Recent studies on altered translational regulation during pathological cardiac hypertrophy are contributing to our understanding of disease progression. In this brief review, we describe how the translational machinery is modulated for enhanced global and transcript selective protein synthesis, and how alternative modes of translation contribute to the disease state. Attempts at controlling translational output through targeting of mTOR and its regulatory components are detailed, as well as recently emerging targets for pre-clinical investigation.
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Yoshie K, Rajendran PS, Massoud L, Mistry J, Swid MA, Wu X, Sallam T, Zhang R, Goldhaber JI, Salavatian S, Ajijola OA. Cardiac TRPV1 afferent signaling promotes arrhythmogenic ventricular remodeling after myocardial infarction. JCI Insight 2020; 5:124477. [PMID: 31846438 PMCID: PMC7098788 DOI: 10.1172/jci.insight.124477] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/12/2019] [Indexed: 12/31/2022] Open
Abstract
Chronic sympathoexcitation is implicated in ventricular arrhythmogenesis (VAs) following myocardial infarction (MI), but the critical neural pathways involved are not well understood. Cardiac adrenergic function is partly regulated by sympathetic afferent reflexes, transduced by spinal afferent fibers expressing the transient receptor potential cation subfamily V member 1 (TRPV1) channel. The role of chronic TRPV1 afferent signaling in VAs is not known. We hypothesized that persistent TRPV1 afferent neurotransmission promotes VAs after MI. Using epicardial resiniferatoxin (RTX) to deplete cardiac TRPV1-expressing fibers, we dissected the role of this neural circuit in VAs after chronic MI in a porcine model. We examined the underlying mechanisms using molecular approaches, IHC, in vitro and in vivo cardiac electrophysiology, and simultaneous cardioneural mapping. Epicardial RTX depleted cardiac TRPV1 afferent fibers and abolished functional responses to TRPV1 agonists. Ventricular tachycardia/fibrillation (VT/VF) was readily inducible in MI subjects by programmed electrical stimulation or cesium chloride administration; however, TRPV1 afferent depletion prevented VT/VF induced by either method. Mechanistically, TRPV1 afferent depletion did not alter cardiomyocyte action potentials and calcium transients, the expression of ion channels, or calcium handling proteins. However, it attenuated fibrosis and mitigated electrical instability in the scar border zone. In vivo recordings of cardiovascular-related stellate ganglion neurons (SGNs) revealed that MI enhances SGN function and disrupts integrated neural processing. Depleting TRPV1 afferents normalized these processes. Taken together, these data indicate that, after MI, TRPV1 afferent-induced adrenergic dysfunction promotes fibrosis and adverse cardiac remodeling, and it worsens border zone electrical heterogeneity, resulting in electrically unstable ventricular myocardium. We propose targeting TRPV1-expressing afferent to reduce VT/VF following MI.
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Affiliation(s)
- Koji Yoshie
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
| | - Pradeep S. Rajendran
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
| | - Louis Massoud
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
| | - Janki Mistry
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
| | - M. Amer Swid
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
| | - Xiaohui Wu
- Division of Cardiology, Department of Medicine, and
| | - Tamer Sallam
- Division of Cardiology, Department of Medicine, and
- Molecular Biology Institute, UCLA, Los Angeles, California, USA
| | - Rui Zhang
- Cedars Sinai Heart Institute, Los Angeles, California, USA
| | - Joshua I. Goldhaber
- Cedars Sinai Heart Institute, Los Angeles, California, USA
- Molecular, Cellular and Integrative Physiology Interdepartmental Program, UCLA, Los Angeles, California, USA
| | - Siamak Salavatian
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
| | - Olujimi A. Ajijola
- Cardiac Arrhythmia Center and Neurocardiology Research Program
- Division of Cardiology, Department of Medicine, and
- Molecular, Cellular and Integrative Physiology Interdepartmental Program, UCLA, Los Angeles, California, USA
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Changchien CY, Sung MH, Chang HH, Tsai WC, Peng YS, Chen Y. Uremic toxin indoxyl sulfate suppresses myocardial Cx43 assembly and expression via JNK activation. Chem Biol Interact 2020; 319:108979. [PMID: 32045570 DOI: 10.1016/j.cbi.2020.108979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/30/2020] [Accepted: 02/06/2020] [Indexed: 12/14/2022]
Abstract
Heart rhythm disturbances have been widely recognized as major triggers of cardiovascular (CV) mortality in chronic kidney disease (CKD) patients. Connexin 43 (Cx43)-composed gap junctions are essential in cardiomyocyte synchronization and may be involved in the pathological response to uremic toxins. Indoxyl sulfate (IS) is one of the most dominant uremic toxins that contribute to CKD-related cardiovascular diseases. In primary cultures of rat neonatal cardiomyocytes, we demonstrated that IS treatment decreased spontaneous contraction without impairing viability. In addition, there was disruption of gap junction intercellular communication (GJIC) between cardiomyocytes after 30 min of IS stimulation. IS caused time- and dose-dependent Cx43 redistribution, and the patterns of Cx43 immunostaining returned to baseline while IS stimulation was removed. Furthermore, IS exposure downregulated Cx43 protein and mRNA levels. Elevated JNK1 and JNK2 phosphorylation was further identified after IS exposure in both rat cardiomyocytes and H9c2 cells. The above changes as well as GJIC and Cx43 suppression were reversed by pretreatment with a JNK inhibitor (SP600125). Inhibition of p-JNK attenuated IS-mediated downward trends in Cx43 transcription and translation. In cardiac muscle from nephrectomy-induced CKD mice, an alteration in Cx43 level was identified at intercalated discs. Our findings disclosed that JNK activation might participate in the remodeling of gap junction and Cx43 expression by uremic toxin-IS both in vitro and in vivo.
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Affiliation(s)
- Chih-Ying Changchien
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan; Department of General Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Meng-Ho Sung
- Department of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
| | - Hsin-Han Chang
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Chiuan Tsai
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yu-Sen Peng
- Division of Nephrology, Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan; College of Electrical and Communication Engineering, Yuan Ze University, Taoyuan City, Taiwan.
| | - Ying Chen
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan.
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