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Baines O, Sha R, Kalla M, Holmes AP, Efimov IR, Pavlovic D, O’Shea C. Optical mapping and optogenetics in cardiac electrophysiology research and therapy: a state-of-the-art review. Europace 2024; 26:euae017. [PMID: 38227822 PMCID: PMC10847904 DOI: 10.1093/europace/euae017] [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: 10/20/2023] [Revised: 12/07/2023] [Accepted: 01/12/2024] [Indexed: 01/18/2024] Open
Abstract
State-of-the-art innovations in optical cardiac electrophysiology are significantly enhancing cardiac research. A potential leap into patient care is now on the horizon. Optical mapping, using fluorescent probes and high-speed cameras, offers detailed insights into cardiac activity and arrhythmias by analysing electrical signals, calcium dynamics, and metabolism. Optogenetics utilizes light-sensitive ion channels and pumps to realize contactless, cell-selective cardiac actuation for modelling arrhythmia, restoring sinus rhythm, and probing complex cell-cell interactions. The merging of optogenetics and optical mapping techniques for 'all-optical' electrophysiology marks a significant step forward. This combination allows for the contactless actuation and sensing of cardiac electrophysiology, offering unprecedented spatial-temporal resolution and control. Recent studies have performed all-optical imaging ex vivo and achieved reliable optogenetic pacing in vivo, narrowing the gap for clinical use. Progress in optical electrophysiology continues at pace. Advances in motion tracking methods are removing the necessity of motion uncoupling, a key limitation of optical mapping. Innovations in optoelectronics, including miniaturized, biocompatible illumination and circuitry, are enabling the creation of implantable cardiac pacemakers and defibrillators with optoelectrical closed-loop systems. Computational modelling and machine learning are emerging as pivotal tools in enhancing optical techniques, offering new avenues for analysing complex data and optimizing therapeutic strategies. However, key challenges remain including opsin delivery, real-time data processing, longevity, and chronic effects of optoelectronic devices. This review provides a comprehensive overview of recent advances in optical mapping and optogenetics and outlines the promising future of optics in reshaping cardiac electrophysiology and therapeutic strategies.
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Affiliation(s)
- Olivia Baines
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Edgbastion, Wolfson Drive, Birmingham B15 2TT, UK
| | - Rina Sha
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Edgbastion, Wolfson Drive, Birmingham B15 2TT, UK
| | - Manish Kalla
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Edgbastion, Wolfson Drive, Birmingham B15 2TT, UK
| | - Andrew P Holmes
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Edgbastion, Wolfson Drive, Birmingham B15 2TT, UK
| | - Igor R Efimov
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Medicine, Division of Cardiology, Northwestern University, Evanston, IL, USA
| | - Davor Pavlovic
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Edgbastion, Wolfson Drive, Birmingham B15 2TT, UK
| | - Christopher O’Shea
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Edgbastion, Wolfson Drive, Birmingham B15 2TT, UK
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2
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Pyari G, Bansal H, Roy S. Optogenetically mediated large volume suppression and synchronized excitation of human ventricular cardiomyocytes. Pflugers Arch 2023; 475:1479-1503. [PMID: 37415050 DOI: 10.1007/s00424-023-02831-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/05/2023] [Accepted: 06/13/2023] [Indexed: 07/08/2023]
Abstract
A major challenge in cardiac optogenetics is to have minimally invasive large volume excitation and suppression for effective cardioversion and treatment of tachycardia. It is important to study the effect of light attenuation on the electrical activity of cells in in vivo cardiac optogenetic experiments. In this computational study, we present a detailed analysis of the effect of light attenuation in different channelrhodopsins (ChRs)-expressing human ventricular cardiomyocytes. The study shows that sustained illumination from the myocardium surface used for suppression, simultaneously results in spurious excitation in deeper tissue regions. Tissue depths of suppressed and excited regions have been determined for different opsin expression levels. It is shown that increasing the expression level by 5-fold enhances the depth of suppressed tissue from 2.24 to 3.73 mm with ChR2(H134R) (ChR2 with a single point mutation at position H134), 3.78 to 5.12 mm with GtACR1 (anion-conducting ChR from cryptophyte algae Guillardia theta) and 6.63 to 9.31 mm with ChRmine (a marine opsin gene from Tiarina fusus). Light attenuation also results in desynchrony in action potentials in different tissue regions under pulsed illumination. It is further shown that gradient-opsin expression not only enables suppression up to the same level of tissue depth but also enables synchronized excitation under pulsed illumination. The study is important for the effective treatment of tachycardia and cardiac pacing and for extending the scale of cardiac optogenetics.
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Affiliation(s)
- Gur Pyari
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, India
| | - Himanshu Bansal
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, India
| | - Sukhdev Roy
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, India.
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3
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Marchal GA, Biasci V, Yan P, Palandri C, Campione M, Cerbai E, Loew LM, Sacconi L. Recent advances and current limitations of available technology to optically manipulate and observe cardiac electrophysiology. Pflugers Arch 2023; 475:1357-1366. [PMID: 37770585 PMCID: PMC10567935 DOI: 10.1007/s00424-023-02858-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/28/2023] [Accepted: 09/06/2023] [Indexed: 09/30/2023]
Abstract
Optogenetics, utilising light-reactive proteins to manipulate tissue activity, are a relatively novel approach in the field of cardiac electrophysiology. We here provide an overview of light-activated transmembrane channels (optogenetic actuators) currently applied in strategies to modulate cardiac activity, as well as newly developed variants yet to be implemented in the heart. In addition, we touch upon genetically encoded indicators (optogenetic sensors) and fluorescent dyes to monitor tissue activity, including cardiac transmembrane potential and ion homeostasis. The combination of the two allows for all-optical approaches to monitor and manipulate the heart without any physical contact. However, spectral congestion poses a major obstacle, arising due to the overlap of excitation/activation and emission spectra of various optogenetic proteins and/or fluorescent dyes, resulting in optical crosstalk. Therefore, optogenetic proteins and fluorescent dyes should be carefully selected to avoid optical crosstalk and consequent disruptions in readouts and/or cellular activity. We here present a novel approach to simultaneously monitor transmembrane potential and cytosolic calcium, while also performing optogenetic manipulation. For this, we used the novel voltage-sensitive dye ElectroFluor 730p and the cytosolic calcium indicator X-Rhod-1 in mouse hearts expressing channelrhodopsin-2 (ChR2). By exploiting the isosbestic point of ElectroFluor 730p and avoiding the ChR2 activation spectrum, we here introduce a novel optical imaging and manipulation approach with minimal crosstalk. Future developments in both optogenetic proteins and fluorescent dyes will allow for additional and more optimised strategies, promising a bright future for all-optical approaches in the field of cardiac electrophysiology.
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Affiliation(s)
| | - Valentina Biasci
- European Laboratory for Non-Linear Spectroscopy-LENS, Sesto Fiorentino, Florence, Italy
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Ping Yan
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Chiara Palandri
- Department NeuroFarBa, University of Florence, Florence, Italy
| | - Marina Campione
- Institute of Neuroscience (IN-CNR) and Department of Biomedical Science, University of Padua, Padua, Italy
| | - Elisabetta Cerbai
- European Laboratory for Non-Linear Spectroscopy-LENS, Sesto Fiorentino, Florence, Italy
- Department NeuroFarBa, University of Florence, Florence, Italy
| | - Leslie M Loew
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Leonardo Sacconi
- Institute of Clinical Physiology (IFC-CNR), Florence, Italy.
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany.
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4
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Djemai M, Cupelli M, Boutjdir M, Chahine M. Optical Mapping of Cardiomyocytes in Monolayer Derived from Induced Pluripotent Stem Cells. Cells 2023; 12:2168. [PMID: 37681899 PMCID: PMC10487143 DOI: 10.3390/cells12172168] [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: 07/18/2023] [Revised: 08/21/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023] Open
Abstract
Optical mapping is a powerful imaging technique widely adopted to measure membrane potential changes and intracellular Ca2+ variations in excitable tissues using voltage-sensitive dyes and Ca2+ indicators, respectively. This powerful tool has rapidly become indispensable in the field of cardiac electrophysiology for studying depolarization wave propagation, estimating the conduction velocity of electrical impulses, and measuring Ca2+ dynamics in cardiac cells and tissues. In addition, mapping these electrophysiological parameters is important for understanding cardiac arrhythmia mechanisms. In this review, we delve into the fundamentals of cardiac optical mapping technology and its applications when applied to hiPSC-derived cardiomyocytes and discuss related advantages and challenges. We also provide a detailed description of the processing and analysis of optical mapping data, which is a crucial step in the study of cardiac diseases and arrhythmia mechanisms for extracting and comparing relevant electrophysiological parameters.
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Affiliation(s)
- Mohammed Djemai
- CERVO Brain Research Center, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC G1J 2G3, Canada
| | - Michael Cupelli
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY 11209, USA
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, New York, NY 11203, USA
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY 11209, USA
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, New York, NY 11203, USA
- Department of Medicine, NYU School of Medicine, New York, NY 10016, USA
| | - Mohamed Chahine
- CERVO Brain Research Center, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC G1J 2G3, Canada
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
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5
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Lee P, Hou L, Alibhai FJ, Al-attar R, Simón-Chica A, Redondo-Rodríguez A, Nie Y, Mirotsou M, Laflamme MA, Swaminath G, Filgueiras-Rama D. A fully-automated low-cost cardiac monolayer optical mapping robot. Front Cardiovasc Med 2023; 10:1096884. [PMID: 37283579 PMCID: PMC10240081 DOI: 10.3389/fcvm.2023.1096884] [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: 11/12/2022] [Accepted: 04/24/2023] [Indexed: 06/08/2023] Open
Abstract
Scalable and high-throughput electrophysiological measurement systems are necessary to accelerate the elucidation of cardiac diseases in drug development. Optical mapping is the primary method of simultaneously measuring several key electrophysiological parameters, such as action potentials, intracellular free calcium and conduction velocity, at high spatiotemporal resolution. This tool has been applied to isolated whole-hearts, whole-hearts in-vivo, tissue-slices and cardiac monolayers/tissue-constructs. Although optical mapping of all of these substrates have contributed to our understanding of ion-channels and fibrillation dynamics, cardiac monolayers/tissue-constructs are scalable macroscopic substrates that are particularly amenable to high-throughput interrogation. Here, we describe and validate a scalable and fully-automated monolayer optical mapping robot that requires no human intervention and with reasonable costs. As a proof-of-principle demonstration, we performed parallelized macroscopic optical mapping of calcium dynamics in the well-established neonatal-rat-ventricular-myocyte monolayer plated on standard 35 mm dishes. Given the advancements in regenerative and personalized medicine, we also performed parallelized macroscopic optical mapping of voltage dynamics in human pluripotent stem cell-derived cardiomyocyte monolayers using a genetically encoded voltage indictor and a commonly-used voltage sensitive dye to demonstrate the versatility of our system.
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Affiliation(s)
- Peter Lee
- Novel Arrhythmogenic Mechanisms Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- Essel Research and Development Inc., Toronto, ON, Canada
| | - Luqia Hou
- Cardiometabolic Department, Merck & Co., Inc., South San Francisco, CA, United States
| | - Faisal J. Alibhai
- McEwen Stem Cell Institute, University Health Network, Toronto, ON, Canada
| | - Rasha Al-attar
- McEwen Stem Cell Institute, University Health Network, Toronto, ON, Canada
| | - Ana Simón-Chica
- Novel Arrhythmogenic Mechanisms Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Andrés Redondo-Rodríguez
- Novel Arrhythmogenic Mechanisms Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Yilin Nie
- Cardiometabolic Department, Merck & Co., Inc., South San Francisco, CA, United States
| | - Maria Mirotsou
- Cardiometabolic Department, Merck & Co., Inc., South San Francisco, CA, United States
| | - Michael A. Laflamme
- McEwen Stem Cell Institute, University Health Network, Toronto, ON, Canada
- Peter Munk Cardiac Centre, University Health Network, Toronto, ON, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Gayathri Swaminath
- Cardiometabolic Department, Merck & Co., Inc., South San Francisco, CA, United States
| | - David Filgueiras-Rama
- Novel Arrhythmogenic Mechanisms Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Instituto de Investigación Sanitaria Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
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6
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Formozov A, Dieter A, Wiegert JS. A flexible and versatile system for multi-color fiber photometry and optogenetic manipulation. CELL REPORTS METHODS 2023; 3:100418. [PMID: 37056369 PMCID: PMC10088095 DOI: 10.1016/j.crmeth.2023.100418] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 12/20/2022] [Accepted: 02/08/2023] [Indexed: 03/09/2023]
Abstract
Here, we present simultaneous fiber photometry recordings and optogenetic stimulation based on a multimode fused fiber coupler for both light delivery and collection without the need for dichroic beam splitters. In combination with a multi-color light source and appropriate optical filters, our approach offers remarkable flexibility in experimental design and facilitates the exploration of new molecular tools in vivo at minimal cost. We demonstrate straightforward re-configuration of the setup to operate with green, red, and near-infrared calcium indicators with or without simultaneous optogenetic stimulation and further explore the multi-color photometry capabilities of the system. The ease of assembly, operation, characterization, and customization of this platform holds the potential to foster the development of experimental strategies for multi-color fused fiber photometry combined with optogenetics far beyond its current state.
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Affiliation(s)
- Andrey Formozov
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Neurophysiology, MCTN, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Alexander Dieter
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Neurophysiology, MCTN, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - J. Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Neurophysiology, MCTN, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
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7
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Fang J, Xu D, Wang H, Wu J, Li Y, Yang T, Liu C, Hu N. Scalable and Robust Hollow Nanopillar Electrode for Enhanced Intracellular Action Potential Recording. NANO LETTERS 2023; 23:243-251. [PMID: 36537828 DOI: 10.1021/acs.nanolett.2c04222] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Electrophysiology is a unique biomarker of the electrogenic cells that can perform a disease investigation or drug assessment. In the recent decade, vertical nanoelectrode arrays can successfully achieve a high-quality intracellular electrophysiological study in electrogenic cells and their networks. However, a high success rate and high-quality and long-term intracellular recording using low-cost nanostructures is still a considerable challenge. Herein, we develop a scalable and robust hollow nanopillar electrode to achieve enhanced intracellular recording of cardiomyocytes. The template-based synthesis of vertical hollow nanopillars is compatible with large-scale and efficient microfabrication processes and is convenient to regulate the geometry of hollow nanopillars. Compared with the conventional same-size planar electrode, the regulating height of a hollow nanopillar can achieve high-quality and prolonged intracellular recordings, which can improve the cell-electrode interface for tight coupling and effective electroporation. It is demonstrated that the geometry regulation of a nanostructure is a powerful strategy to enhance intracellular recording.
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Affiliation(s)
- Jiaru Fang
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, People's Republic of China
| | - Dongxin Xu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, People's Republic of China
| | - Hao Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, People's Republic of China
| | - Jin Wu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, People's Republic of China
| | - Ying Li
- School of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, People's Republic of China
| | - Tao Yang
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University and Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, 510055, People's Republic of China
| | - Chuan Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, People's Republic of China
| | - Ning Hu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, People's Republic of China
- Department of Chemistry, Zhejiang University, Hangzhou 310058, People's Republic of China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
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8
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Ripplinger CM, Glukhov AV, Kay MW, Boukens BJ, Chiamvimonvat N, Delisle BP, Fabritz L, Hund TJ, Knollmann BC, Li N, Murray KT, Poelzing S, Quinn TA, Remme CA, Rentschler SL, Rose RA, Posnack NG. Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals. Am J Physiol Heart Circ Physiol 2022; 323:H1137-H1166. [PMID: 36269644 PMCID: PMC9678409 DOI: 10.1152/ajpheart.00439.2022] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 01/09/2023]
Abstract
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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Affiliation(s)
- Crystal M Ripplinger
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Alexey V Glukhov
- Department of Medicine, Cardiovascular Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Bastiaan J Boukens
- Department Physiology, University Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Nipavan Chiamvimonvat
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
- Department of Internal Medicine, University of California Davis School of Medicine, Davis, California
- Veterans Affairs Northern California Healthcare System, Mather, California
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Larissa Fabritz
- University Center of Cardiovascular Science, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf with DZHK Hamburg/Kiel/Luebeck, Germany
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Thomas J Hund
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
- Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Na Li
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Katherine T Murray
- Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Steven Poelzing
- Virginia Tech Carilon School of Medicine, Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech, Roanoke, Virginia
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Stacey L Rentschler
- Cardiovascular Division, Department of Medicine, Washington University in Saint Louis, School of Medicine, Saint Louis, Missouri
| | - Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nikki G Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Department of Pediatrics, George Washington University School of Medicine, Washington, District of Columbia
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Peyronnet R, Desai A, Edelmann JC, Cameron BA, Emig R, Kohl P, Dean D. Simultaneous assessment of radial and axial myocyte mechanics by combining atomic force microscopy and carbon fibre techniques. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210326. [PMID: 36189808 PMCID: PMC9527909 DOI: 10.1098/rstb.2021.0326] [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: 03/31/2022] [Accepted: 07/21/2022] [Indexed: 11/12/2022] Open
Abstract
Cardiomyocytes sense and shape their mechanical environment, contributing to its dynamics by their passive and active mechanical properties. While axial forces generated by contracting cardiomyocytes have been amply investigated, the corresponding radial mechanics remain poorly characterized. Our aim is to simultaneously monitor passive and active forces, both axially and radially, in cardiomyocytes freshly isolated from adult mouse ventricles. To do so, we combine a carbon fibre (CF) set-up with a custom-made atomic force microscope (AFM). CF allows us to apply stretch and to record passive and active forces in the axial direction. The AFM, modified for frontal access to fit in CF, is used to characterize radial cell mechanics. We show that stretch increases the radial elastic modulus of cardiomyocytes. We further find that during contraction, cardiomyocytes generate radial forces that are reduced, but not abolished, when cells are forced to contract near isometrically. Radial forces may contribute to ventricular wall thickening during contraction, together with the dynamic re-orientation of cells and sheetlets in the myocardium. This new approach for characterizing cell mechanics allows one to obtain a more detailed picture of the balance of axial and radial mechanics in cardiomyocytes at rest, during stretch, and during contraction. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg – Bad Krozingen, University of Freiburg, 79110 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
- National Heart and Lung Institute, Imperial College London, London, UK
| | | | | | - Breanne A. Cameron
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg – Bad Krozingen, University of Freiburg, 79110 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Ramona Emig
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg – Bad Krozingen, University of Freiburg, 79110 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg – Bad Krozingen, University of Freiburg, 79110 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
- National Heart and Lung Institute, Imperial College London, London, UK
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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10
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Pyari G, Bansal H, Roy S. Ultra-low power deep sustained optogenetic excitation of human ventricular cardiomyocytes with red-shifted opsins: A computational study. J Physiol 2022; 600:4653-4676. [PMID: 36068951 DOI: 10.1113/jp283366] [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: 05/25/2022] [Accepted: 08/31/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Formulation of accurate theoretical models of optogenetic control of HVCMs expressed with newly-discovered opsins (ChRmine, bReaChES, and CsChrimson). Under continuous illumination, action potentials in each opsin-expressing HVCMs can only be evoked in a certain range of irradiances. Action potentials in ChRmine-expressing HVCMs can be triggered at ultra-low power (6 μW/mm2 at 10 ms pulse or 0.7 μW/mm2 at 100 ms pulse at 585 nm), which is 2-3 orders of magnitude lower than reported results. Ongoing APs in ChRmine-expressing HVCMs can be suppressed by continuous illumination of 585 nm light at 2 μW/mm2 . ChRmine enables sustained excitation due to its faster recovery from the desensitized state. Optogenetic excitation of deeply situated cardiac cells is possible upto ∼ 7.46 mm and 10.2 mm with ChRmine on illuminating the outer surface of pericardium at safe irradiance at 585 nm and 650 nm, respectively. The study opens up prospects for designing energy-efficient light-induced pacemakers, resynchronization, and termination of ventricular tachycardia. ABSTRACT The main challenge in cardiac optogenetics is to have low-power, high-fidelity, and deep excitation of cells with minimal invasiveness and heating. We present a detailed computational study of optogenetic excitation of human ventricular cardiomyocytes (HVCMs) with new ChRmine, bReaChES and CsChrimson red-shifted opsins to overcome the challenge. Action potentials (APs) in ChRmine expressing HVCMs can be triggered at 6 μW/mm2 (10 ms pulse) and 0.7 μW/mm2 (100 ms pulse) at 585 nm which are two orders of magnitude lower than ChR2(H134R). This enables safe sustained excitation of deeply situated cardiac cells with ChRmine (7.46 mm) and with bReaChES (6.21 mm) with the light source at the pericardium surface. Deeper excitation upto 10.2 mm can be achieved with ChRmine by illuminating at 650 nm. Photostimulation conditions for minimum charge transfer during AP have been determined, which are important for tissue health under sustained excitation. The action potential duration for all the opsins is constant upto 100 ms pulse-width but increases thereafter. Interestingly, the AP frequency increases with irradiance under continuous illumination, which gets suppressed at higher irradiances. Optimal range of irradiance for each opsin to excite HVCMs has been determined. Under optimal photostimulation conditions, each opsin can precisely excite APs up to 2.5 Hz, while latency and power of light pulse for each AP in a sequence remain most stable and an order lower respectively, in ChRmine-expressing HVCMs. The study highlights the importance of ChRmine and bReaChES for resynchronization, termination of ventricular tachycardia, and designing optogenetic cardiac pacemakers with enhanced battery life. Abstract figure legend Deep optogenetic excitation of opsin-expressing cardiomyocytes by placing the light source (maximum output 5.5 mW/mm2 ) at the outer surface of the pericardium. Excitation of cardiomyocytes upto 10.2 mm (at 650 nm) and 7.46 mm (at 585 nm) is possible with ChRmine. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Gur Pyari
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
| | - Himanshu Bansal
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
| | - Sukhdev Roy
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
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11
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Two-Wavelength Computational Holography for Aberration-Corrected Simultaneous Optogenetic Stimulation and Inhibition of In Vitro Biological Samples. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12052283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Optogenetics is a versatile toolset for the functional investigation of excitable cells such as neurons and cardiomyocytes in vivo and in vitro. While monochromatic illumination of these cells for either stimulation or inhibition already enables a wide range of studies, the combination of activation and silencing in one setup facilitates new experimental interrogation protocols. In this work, we present a setup for the simultaneous holographic stimulation and inhibition of multiple cells in vitro. The system is based on two fast ferroelectric liquid crystal spatial light modulators with frame rates of up to 1.7 kHz. Thereby, we are able to illuminate up to about 50 single spots with better than cellular resolution and without crosstalk, perfectly suited for refined network analysis schemes. System-inherent aberrations are corrected by applying an iterative optimization scheme based on Zernike polynomials. These are superposed on the same spatial light modulators that display the pattern-generating holograms, hence no further adaptive optical elements are needed for aberration correction. A near-diffraction-limited spatial resolution is achieved over the whole field of view, enabling subcellular optogenetic experiments by just choosing an appropriate microscope objective. The setup can pave the way for a multitude of optogenetic experiments, in particular with cardiomyocytes and neural networks.
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12
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Cumberland MJ, Riebel LL, Roy A, O’Shea C, Holmes AP, Denning C, Kirchhof P, Rodriguez B, Gehmlich K. Basic Research Approaches to Evaluate Cardiac Arrhythmia in Heart Failure and Beyond. Front Physiol 2022; 13:806366. [PMID: 35197863 PMCID: PMC8859441 DOI: 10.3389/fphys.2022.806366] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 01/10/2022] [Indexed: 12/20/2022] Open
Abstract
Patients with heart failure often develop cardiac arrhythmias. The mechanisms and interrelations linking heart failure and arrhythmias are not fully understood. Historically, research into arrhythmias has been performed on affected individuals or in vivo (animal) models. The latter however is constrained by interspecies variation, demands to reduce animal experiments and cost. Recent developments in in vitro induced pluripotent stem cell technology and in silico modelling have expanded the number of models available for the evaluation of heart failure and arrhythmia. An agnostic approach, combining the modalities discussed here, has the potential to improve our understanding for appraising the pathology and interactions between heart failure and arrhythmia and can provide robust and validated outcomes in a variety of research settings. This review discusses the state of the art models, methodologies and techniques used in the evaluation of heart failure and arrhythmia and will highlight the benefits of using them in combination. Special consideration is paid to assessing the pivotal role calcium handling has in the development of heart failure and arrhythmia.
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Affiliation(s)
- Max J. Cumberland
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Leto L. Riebel
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Ashwin Roy
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Christopher O’Shea
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew P. Holmes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Chris Denning
- Stem Cell Biology Unit, Biodiscovery Institute, British Heart Foundation Centre for Regenerative Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- University Heart and Vascular Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Blanca Rodriguez
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Katja Gehmlich
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford and British Heart Foundation Centre of Research Excellence Oxford, Oxford, United Kingdom
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13
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Madrid MK, Brennan JA, Yin RT, Knight HS, Efimov IR. Advances in Implantable Optogenetic Technology for Cardiovascular Research and Medicine. Front Physiol 2021; 12:720190. [PMID: 34675815 PMCID: PMC8523791 DOI: 10.3389/fphys.2021.720190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
Optogenetic technology provides researchers with spatiotemporally precise tools for stimulation, sensing, and analysis of function in cells, tissues, and organs. These tools can offer low-energy and localized approaches due to the use of the transgenically expressed light gated cation channel Channelrhodopsin-2 (ChR2). While the field began with many neurobiological accomplishments it has also evolved exceptionally well in animal cardiac research, both in vitro and in vivo. Implantable optical devices are being extensively developed to study particular electrophysiological phenomena with the precise control that optogenetics provides. In this review, we highlight recent advances in novel implantable optogenetic devices and their feasibility in cardiac research. Furthermore, we also emphasize the difficulties in translating this technology toward clinical applications and discuss potential solutions for successful clinical translation.
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Affiliation(s)
- Micah K Madrid
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Jaclyn A Brennan
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Rose T Yin
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Helen S Knight
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Igor R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
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14
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Rieger M, Dellenbach C, Vom Berg J, Beil-Wagner J, Maguy A, Rohr S. Enabling comprehensive optogenetic studies of mouse hearts by simultaneous opto-electrical panoramic mapping and stimulation. Nat Commun 2021; 12:5804. [PMID: 34608155 PMCID: PMC8490461 DOI: 10.1038/s41467-021-26039-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/15/2021] [Indexed: 11/09/2022] Open
Abstract
During the last decade, cardiac optogenetics has turned into an essential tool for investigating cardiac function in general and for assessing functional interactions between different myocardial cell types in particular. To advance exploitation of the unique research opportunities offered by this method, we develop a panoramic opto-electrical measurement and stimulation (POEMS) system for mouse hearts. The core of the experimental platform is composed of 294 optical fibers and 64 electrodes that form a cup which embraces the entire ventricular surface of mouse hearts and enables straightforward ‘drop&go’ experimentation. The flexible assignment of fibers and electrodes to recording or stimulation tasks permits a precise tailoring of experiments to the specific requirements of individual optogenetic constructs thereby avoiding spectral congestion. Validation experiments with hearts from transgenic animals expressing the optogenetic voltage reporters ASAP1 and ArcLight-Q239 demonstrate concordance of simultaneously recorded panoramic optical and electrical activation maps. The feasibility of single fiber optical stimulation is proven with hearts expressing the optogenetic voltage actuator ReaChR. Adaptation of the POEMS system to larger hearts and incorporation of additional sensors can be achieved by redesigning the system-core accordingly. Current cardiac mapping systems provide either electrical or optical readouts. Here the authors report a panoramic opto-electrical measurement and stimulation (POEMS) system which embraces the entire ventricular surface of mouse hearts, allowing flexible combinations of optical and electrical recording and stimulation modalities.
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Affiliation(s)
- Michael Rieger
- Department of Physiology, University of Bern, Bühlplatz 5, Bern, Switzerland
| | | | - Johannes Vom Berg
- Institute of Laboratory Animal Science, University of Zürich, Wagistrasse 12, Schlieren, Switzerland
| | - Jane Beil-Wagner
- Institute of Laboratory Animal Science, University of Zürich, Wagistrasse 12, Schlieren, Switzerland
| | - Ange Maguy
- Department of Physiology, University of Bern, Bühlplatz 5, Bern, Switzerland
| | - Stephan Rohr
- Department of Physiology, University of Bern, Bühlplatz 5, Bern, Switzerland.
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15
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Majumder R, Mohamed Nazer AN, Panfilov AV, Bodenschatz E, Wang Y. Electrophysiological Characterization of Human Atria: The Understated Role of Temperature. Front Physiol 2021; 12:639149. [PMID: 34366877 PMCID: PMC8346027 DOI: 10.3389/fphys.2021.639149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
Ambient temperature has a profound influence on cellular electrophysiology through direct control over the gating mechanisms of different ion channels. In the heart, low temperature is known to favor prolongation of the action potential. However, not much is known about the influence of temperature on other important characterization parameters such as the resting membrane potential (RMP), excitability, morphology and characteristics of the action potential (AP), restitution properties, conduction velocity (CV) of signal propagation, etc. Here we present the first, detailed, systematic in silico study of the electrophysiological characterization of cardiomyocytes from different regions of the normal human atria, based on the effects of ambient temperature (5-50°C). We observe that RMP decreases with increasing temperature. At ~ 48°C, the cells lose their excitability. Our studies show that different parts of the atria react differently to the same changes in temperature. In tissue simulations a drop in temperature correlated positively with a decrease in CV, but the decrease was region-dependent, as expected. In this article we show how this heterogeneous response can provide an explanation for the development of a proarrhythmic substrate during mild hypothermia. We use the above concept to propose a treatment strategy for atrial fibrillation that involves severe hypothermia in specific regions of the heart for a duration of only ~ 200 ms.
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Affiliation(s)
- Rupamanjari Majumder
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | | | - Alexander V Panfilov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov University, Moscow, Russia.,Department of Physics and Astronomy, Ghent University, Ghent, Belgium.,Laboratory of Computational Biology and Medicine, Ural Federal University, Yekaterinburg, Russia
| | - Eberhard Bodenschatz
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Laboratory of Atomic and Solid-State Physics and Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | - Yong Wang
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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16
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Wang TW, Sung YL, Chu HW, Lin SF. IPG-based field potential measurement of cultured cardiomyocytes for optogenetic applications. Biosens Bioelectron 2021; 179:113060. [PMID: 33571936 DOI: 10.1016/j.bios.2021.113060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/15/2021] [Accepted: 01/28/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND Electrophysiological sensing of cardiomyocytes (CMs) in optogenetic preparations applies various techniques, such as patch-clamp, microelectrode array, and optical mapping. However, challenges remain in decreasing the cost, system dimensions, and operating skills required for these technologies. OBJECTIVE This study developed a low-cost, portable impedance plethysmography (IPG)-based electrophysiological measurement of cultured CMs for optogenetic applications. METHODS To validate the efficacy of the proposed sensor, optogenetic stimulation with different pacing cycle lengths (PCL) was performed to evaluate whether the channelrhodopsin-2 (ChR2)-expressing CM beating rhythm measured by the IPG sensor was consistent with biological responses. RESULTS The experimental results show that the CM field potential was synchronized with external optical pacing with PCLs ranging from 250 ms to 1000 ms. Moreover, irregular fibrillating waveforms induced by CM arrhythmia were detected after overdrive optical pacing. Through the combined evidence of the theoretical model and experimental results, this study confirmed the feasibility of long-term electrophysiological sensing for optogenetic CMs. CONCLUSION This study proposes an IPG-based sensor that is low-cost, portable, and requires low-operating skills to perform real-time CM field potential measurement in response to optogenetic stimulation. SIGNIFICANCE This study demonstrates a new methodology for convenient electrophysiological sensing of CMs in optogenetic applications.
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Affiliation(s)
- Ting-Wei Wang
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, 30010, Hsinchu, Taiwan
| | - Yen-Ling Sung
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, 30010, Hsinchu, Taiwan
| | - Hsiao-Wei Chu
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, 30010, Hsinchu, Taiwan
| | - Shien-Fong Lin
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, 30010, Hsinchu, Taiwan.
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17
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Li J, Li H, Rao P, Luo J, Wang X, Wang L. Shining light on cardiac electrophysiology: From detection to intervention, from basic research to translational applications. Life Sci 2021; 274:119357. [PMID: 33737082 DOI: 10.1016/j.lfs.2021.119357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
Cardiac arrhythmias are an important group of cardiovascular diseases, which can occur alone or in association with other cardiovascular diseases. The development of cardiac arrhythmias cannot be separated from changes in cardiac electrophysiology, and the investigation and clarification of cardiac electrophysiological changes are beneficial for the treatment of cardiac arrhythmias. However, electrical energy-based pacemakers and defibrillators, which are widely used to treat arrhythmias, still have certain disadvantages. Thereby, optics promises to be used for optical manipulation and its use in biomedicine is increasing. Since visible light is readily absorbed and scattered in living tissues and tissue penetration is shallow, optical modulation for cells and tissues requires conversion media that convert light energy into bioelectrical activity. In this regard, fluorescent dyes, light-sensitive ion channels, and optical nanomaterials can assume this role, the corresponding optical mapping technology, optogenetics technology, and optical systems based on luminescent nanomaterials have been introduced into the research in cardiovascular field and are expected to be new tools for the study and treatment of cardiac arrhythmias. In addition, infrared and near-infrared light has strong tissue penetration, which is one of the excellent options of external trigger for achieving optical modulation, and is also widely used in the study of optical modulation of biological activities. Here, the advantages of optical applications are summarized, the research progresses and emerging applications of optical-based technologies as detection and intervention tools for cardiac electrophysiological are highlighted. Moreover, the prospects for future applications of optics in clinical diagnosis and treatment are discussed.
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Affiliation(s)
- Jianyi Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Haitao Li
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou 570311, PR China
| | - Panpan Rao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Junmiao Luo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China.
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China; Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China.
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18
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Meki MH, Miller JM, Mohamed TMA. Heart Slices to Model Cardiac Physiology. Front Pharmacol 2021; 12:617922. [PMID: 33613292 PMCID: PMC7890402 DOI: 10.3389/fphar.2021.617922] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/05/2021] [Indexed: 12/02/2022] Open
Abstract
Translational research in the cardiovascular field is hampered by the unavailability of cardiac models that can recapitulate organ-level physiology of the myocardium. Outside the body, cardiac tissue undergoes rapid dedifferentiation and maladaptation in culture. There is an ever-growing demand for preclinical platforms that allow for accurate, standardized, long-term, and rapid drug testing. Heart slices is an emerging technology that solves many of the problems with conventional myocardial culture systems. Heart slices are thin (<400 µm) slices of heart tissue from the adult ventricle. Several recent studies using heart slices have shown their ability to maintain the adult phenotype for prolonged periods in a multi cell-type environment. Here, we review the current status of cardiac culture systems and highlight the unique advantages offered by heart slices in the light of recent efforts in developing physiologically relevant heart slice culture systems.
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Affiliation(s)
- Moustafa H Meki
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, KY, United States.,Department of Bioengineering, University of Louisville, Louisville, KY, United States
| | - Jessica M Miller
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, KY, United States.,Department of Bioengineering, University of Louisville, Louisville, KY, United States
| | - Tamer M A Mohamed
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, KY, United States.,Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, United States.,Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
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19
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Abstract
The electromechanical function of the heart involves complex, coordinated activity over time and space. Life-threatening cardiac arrhythmias arise from asynchrony in these space-time events; therefore, therapies for prevention and treatment require fundamental understanding and the ability to visualize, perturb and control cardiac activity. Optogenetics combines optical and molecular biology (genetic) approaches for light-enabled sensing and actuation of electrical activity with unprecedented spatiotemporal resolution and parallelism. The year 2020 marks a decade of developments in cardiac optogenetics since this technology was adopted from neuroscience and applied to the heart. In this Review, we appraise a decade of advances that define near-term (immediate) translation based on all-optical electrophysiology, including high-throughput screening, cardiotoxicity testing and personalized medicine assays, and long-term (aspirational) prospects for clinical translation of cardiac optogenetics, including new optical therapies for rhythm control. The main translational opportunities and challenges for optogenetics to be fully embraced in cardiology are also discussed.
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20
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Li A, Tanzi RE. <p>Optogenetic Pacing: Current Insights and Future Potential</p>. RESEARCH REPORTS IN CLINICAL CARDIOLOGY 2020. [DOI: 10.2147/rrcc.s242650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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21
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Li J, Wang L, Luo J, Li H, Rao P, Cheng Y, Wang X, Huang C. Optical capture and defibrillation in rats with monocrotaline-induced myocardial fibrosis 1 year after a single intravenous injection of adeno-associated virus channelrhodopsin-2. Heart Rhythm 2020; 18:109-117. [PMID: 32781160 DOI: 10.1016/j.hrthm.2020.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/28/2020] [Accepted: 08/04/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Optogenetics uses light to regulate cardiac rhythms and terminate malignant arrhythmias. OBJECTIVE The purpose of this study was to investigate the long-term validity of optical capture properties based on virus-transfected channelrhodopsin-2 (ChR2) and evaluate the effects of optogenetic-based defibrillation in an in vivo rat model of myocardial fibrosis enhanced by monocrotaline (MCT). METHODS Fifteen infant rats received jugular vein injection of adeno-associated virus (AAV). After 8 weeks, 5 rats were randomly selected to verify the effectiveness ChR2 transfection. The remaining rats were administered MCT at 11 months. Four weeks after MCT, the availability of 473-nm blue light to capture heart rhythm in these rats was verified again. Ventricular tachycardia (VT) and ventricular fibrillation (VF) were induced by burst stimulation on the basis of enhanced myocardial fibrosis, and the termination effects of the optical manipulation were tested. RESULTS Eight weeks after AAV injection, there was ChR2 expression throughout the ventricular myocardium as reflected by both fluorescence imaging and optical pacing. Four weeks after MCT, significant myocardial fibrosis was achieved. Light could still trigger the corresponding ectopic heart rhythm, and the pulse width and illumination area could affect the light capture rate. VT/VF was induced successfully in 1-year-observation rats, and the rate of termination of VT/VF under light was much higher than that of spontaneous termination. CONCLUSION Viral ChR2 transfection can play a long-term role in the rat heart, and light can successfully regulate heart rhythm and defibrillate after cardiac fibrosis.
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Affiliation(s)
- Jianyi Li
- 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, People's Republic of China
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China; Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
| | - Junmiao Luo
- 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, People's Republic of China
| | - Haitao Li
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, Hainan Province, People's Republic of China
| | - Panpan Rao
- 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, People's Republic of China
| | - Yue Cheng
- 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, People's Republic of China
| | - Xi Wang
- 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, People's Republic of China.
| | - Congxin Huang
- 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, People's Republic of China.
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22
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O'Shea C, Kabir SN, Holmes AP, Lei M, Fabritz L, Rajpoot K, Pavlovic D. Cardiac optical mapping - State-of-the-art and future challenges. Int J Biochem Cell Biol 2020; 126:105804. [PMID: 32681973 PMCID: PMC7456775 DOI: 10.1016/j.biocel.2020.105804] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 11/06/2022]
Abstract
Cardiac optical mapping is a fluorescent imaging method to study electrical behaviour and calcium handling in the heart. Optical mapping provides higher spatio-temporal resolution than electrode techniques, allowing unique insights into cardiac electrophysiology in health and disease from a variety of pre-clinical models. Both transmembrane voltage and intracellular calcium dynamics can be studied with the use of appropriate fluorescent dyes. Optical mapping has traditionally required the use of mechanical uncouplers, however computational and technical developments have lessened the requirement for these agents. Novel fluorescent dyes have been developed to optimise spectral properties, experimental timescales, biological compatibility and fluorescence output. The combination of these developments has made possible novel mapping experiments, including recent in vivo application of the technique.
Cardiac optical mapping utilises fluorescent dyes to directly image the electrical function of the heart at a high spatio-temporal resolution which far exceeds electrode techniques. It has therefore become an invaluable tool in cardiac electrophysiological research to map the propagation of heterogeneous electrical signals across the myocardium. In this review, we introduce the principles behind cardiac optical mapping and discuss some of the challenges and state of the art in the field. Key advancements discussed include newly developed fluorescent indicators, tools for the analysis of complex datasets, panoramic imaging systems and technical and computational approaches to realise optical mapping in freely beating hearts.
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Affiliation(s)
- Christopher O'Shea
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK
| | - S Nashitha Kabir
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK
| | - Andrew P Holmes
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK; Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK; Department Cardiology, University Hospital Birmingham, Birmingham, UK
| | - Kashif Rajpoot
- School of Computer Science, University of Birmingham, Birmingham, UK
| | - Davor Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK.
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23
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Desbiolles BXE, Hannebelle MTM, de Coulon E, Bertsch A, Rohr S, Fantner GE, Renaud P. Volcano-Shaped Scanning Probe Microscopy Probe for Combined Force-Electrogram Recordings from Excitable Cells. NANO LETTERS 2020; 20:4520-4529. [PMID: 32426984 PMCID: PMC7291358 DOI: 10.1021/acs.nanolett.0c01319] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/19/2020] [Indexed: 05/30/2023]
Abstract
Atomic force microscopy based approaches have led to remarkable advances in the field of mechanobiology. However, linking the mechanical cues to biological responses requires complementary techniques capable of recording these physiological characteristics. In this study, we present an instrument for combined optical, force, and electrical measurements based on a novel type of scanning probe microscopy cantilever composed of a protruding volcano-shaped nanopatterned microelectrode (nanovolcano probe) at the tip of a suspended microcantilever. This probe enables simultaneous force and electrical recordings from single cells. Successful impedance measurements on mechanically stimulated neonatal rat cardiomyocytes in situ were achieved using these nanovolcano probes. Furthermore, proof of concept experiments demonstrated that extracellular field potentials (electrogram) together with contraction displacement curves could simultaneously be recorded. These features render the nanovolcano probe especially suited for mechanobiological studies aiming at linking mechanical stimuli to electrophysiological responses of single cells.
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Affiliation(s)
- B. X. E. Desbiolles
- Laboratory
of Microsystems LMIS4, Ecole Polytechnique
Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - M. T. M Hannebelle
- Laboratory
of Bio- and Nano- Instrumentation, Ecole
Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - E. de Coulon
- Laboratory
of Cellular Optics II, Department of Physiology, University of Bern, Bern 3012, Switzerland
| | - A. Bertsch
- Laboratory
of Microsystems LMIS4, Ecole Polytechnique
Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - S. Rohr
- Laboratory
of Cellular Optics II, Department of Physiology, University of Bern, Bern 3012, Switzerland
| | - G. E. Fantner
- Laboratory
of Bio- and Nano- Instrumentation, Ecole
Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - P. Renaud
- Laboratory
of Microsystems LMIS4, Ecole Polytechnique
Fédérale de Lausanne, Lausanne 1015, Switzerland
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24
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Sigalas C, Cremer M, Winbo A, Bose SJ, Ashton JL, Bub G, Montgomery JM, Burton RAB. Combining tissue engineering and optical imaging approaches to explore interactions along the neuro-cardiac axis. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200265. [PMID: 32742694 PMCID: PMC7353978 DOI: 10.1098/rsos.200265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/27/2020] [Indexed: 05/05/2023]
Abstract
Interactions along the neuro-cardiac axis are being explored with regard to their involvement in cardiac diseases, including catecholaminergic polymorphic ventricular tachycardia, hypertension, atrial fibrillation, long QT syndrome and sudden death in epilepsy. Interrogation of the pathophysiology and pathogenesis of neuro-cardiac diseases in animal models present challenges resulting from species differences, phenotypic variation, developmental effects and limited availability of data relevant at both the tissue and cellular level. By contrast, tissue-engineered models containing cardiomyocytes and peripheral sympathetic and parasympathetic neurons afford characterization of cellular- and tissue-level behaviours while maintaining precise control over developmental conditions, cellular genotype and phenotype. Such approaches are uniquely suited to long-term, high-throughput characterization using optical recording techniques with the potential for increased translational benefit compared to more established techniques. Furthermore, tissue-engineered constructs provide an intermediary between whole animal/tissue experiments and in silico models. This paper reviews the advantages of tissue engineering methods of multiple cell types and optical imaging techniques for the characterization of neuro-cardiac diseases.
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Affiliation(s)
| | - Maegan Cremer
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Annika Winbo
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Department of Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand
| | - Samuel J. Bose
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Jesse L. Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Gil Bub
- Department of Physiology, McGill University, Montreal, Canada
| | | | - Rebecca A. B. Burton
- Department of Pharmacology, University of Oxford, Oxford, UK
- Author for correspondence: Rebecca A. B. Burton e-mail:
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25
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Pitoulis FG, Watson SA, Perbellini F, Terracciano CM. Myocardial slices come to age: an intermediate complexity in vitro cardiac model for translational research. Cardiovasc Res 2020; 116:1275-1287. [PMID: 31868875 PMCID: PMC7243278 DOI: 10.1093/cvr/cvz341] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/31/2019] [Accepted: 12/19/2019] [Indexed: 12/17/2022] Open
Abstract
Although past decades have witnessed significant reductions in mortality of heart failure together with advances in our understanding of its cellular, molecular, and whole-heart features, a lot of basic cardiac research still fails to translate into clinical practice. In this review we examine myocardial slices, a novel model in the translational arena. Myocardial slices are living ultra-thin sections of heart tissue. Slices maintain the myocardium's native function (contractility, electrophysiology) and structure (multicellularity, extracellular matrix) and can be prepared from animal and human tissue. The discussion begins with the history and current advances in the model, the different interlaboratory methods of preparation and their potential impact on results. We then contextualize slices' advantages and limitations by comparing it with other cardiac models. Recently, sophisticated methods have enabled slices to be cultured chronically in vitro while preserving the functional and structural phenotype. This is more timely now than ever where chronic physiologically relevant in vitro platforms for assessment of therapeutic strategies are urgently needed. We interrogate the technological developments that have permitted this, their limitations, and future directions. Finally, we look into the general obstacles faced by the translational field, and how implementation of research systems utilizing slices could help in resolving these.
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Affiliation(s)
- Fotios G Pitoulis
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Samuel A Watson
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Filippo Perbellini
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
- Hannover Medical School, Institute of Molecular and Translational Therapeutic Strategies, Hannover, Germany
| | - Cesare M Terracciano
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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26
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Desbiolles BXE, de Coulon E, Bertsch A, Rohr S, Renaud P. Intracellular Recording of Cardiomyocyte Action Potentials with Nanopatterned Volcano-Shaped Microelectrode Arrays. NANO LETTERS 2019; 19:6173-6181. [PMID: 31424942 DOI: 10.1021/acs.nanolett.9b02209] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Micronanotechnology-based multielectrode arrays have led to remarkable progress in the field of transmembrane voltage recording of excitable cells. However, providing long-term optoporation- or electroporation-free intracellular access remains a considerable challenge. In this study, a novel type of nanopatterned volcano-shaped microelectrode (nanovolcano) is described that spontaneously fuses with the cell membrane and permits stable intracellular access. The complex nanostructure was manufactured following a simple and scalable fabrication process based on ion beam etching redeposition. The resulting ring-shaped structure provided passive intracellular access to neonatal rat cardiomyocytes. Intracellular action potentials were successfully recorded in vitro from different devices, and continuous recording for more than 1 h was achieved. By reporting transmembrane action potentials at potentially high spatial resolution without the need to apply physical triggers, the nanovolcanoes show distinct advantages over multielectrode arrays for the assessment of electrophysiological characteristics of cardiomyocyte networks at the transmembrane voltage level over time.
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Affiliation(s)
- B X E Desbiolles
- Laboratory of Microsystems LMIS4 , Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
| | - E de Coulon
- Group Rohr, Department of Physiology , University of Bern , 3012 Bern , Switzerland
| | - A Bertsch
- Laboratory of Microsystems LMIS4 , Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
| | - S Rohr
- Group Rohr, Department of Physiology , University of Bern , 3012 Bern , Switzerland
| | - P Renaud
- Laboratory of Microsystems LMIS4 , Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
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27
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Ferenczi EA, Tan X, Huang CLH. Principles of Optogenetic Methods and Their Application to Cardiac Experimental Systems. Front Physiol 2019; 10:1096. [PMID: 31572204 PMCID: PMC6749684 DOI: 10.3389/fphys.2019.01096] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
Optogenetic techniques permit studies of excitable tissue through genetically expressed light-gated microbial channels or pumps permitting transmembrane ion movement. Light activation of these proteins modulates cellular excitability with millisecond precision. This review summarizes optogenetic approaches, using examples from neurobiological applications, and then explores their application in cardiac electrophysiology. We review the available opsins, including depolarizing and hyperpolarizing variants, as well as modulators of G-protein coupled intracellular signaling. We discuss the biophysical properties that determine the ability of microbial opsins to evoke reliable, precise stimulation or silencing of electrophysiological activity. We also review spectrally shifted variants offering possibilities for enhanced depth of tissue penetration, combinatorial stimulation for targeting different cell subpopulations, or all-optical read-in and read-out studies. Expression of the chosen optogenetic tool in the cardiac cell of interest then requires, at the single-cell level, introduction of opsin-encoding genes by viral transduction, or coupling "spark cells" to primary cardiomyocytes or a stem-cell derived counterpart. At the system-level, this requires construction of transgenic mice expressing ChR2 in their cardiomyocytes, or in vivo injection (myocardial or systemic) of adenoviral expression systems. Light delivery, by laser or LED, with widespread or multipoint illumination, although relatively straightforward in vitro may be technically challenged by cardiac motion and light-scattering in biological tissue. Physiological read outs from cardiac optogenetic stimulation include single cell patch clamp recordings, multi-unit microarray recordings from cell monolayers or slices, and electrical recordings from isolated Langendorff perfused hearts. Optical readouts of specific cellular events, including ion transients, voltage changes or activity in biochemical signaling cascades, using small detecting molecules or genetically encoded sensors now offer powerful opportunities for all-optical control and monitoring of cellular activity. Use of optogenetics has expanded in cardiac physiology, mainly using optically controlled depolarizing ion channels to control heart rate and for optogenetic defibrillation. ChR2-expressing cardiomyocytes show normal baseline and active excitable membrane and Ca2+ signaling properties and are sensitive even to ~1 ms light pulses. They have been employed in studies of the intrinsic cardiac adrenergic system and of cardiac arrhythmic properties.
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Affiliation(s)
- Emily A. Ferenczi
- Department of Neurology, Massachusetts General Hospital and Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - 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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28
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Stanley CE, Mauss AS, Borst A, Cooper RL. The Effects of Chloride Flux on Drosophila Heart Rate. Methods Protoc 2019; 2:mps2030073. [PMID: 31443492 PMCID: PMC6789470 DOI: 10.3390/mps2030073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/15/2019] [Accepted: 08/20/2019] [Indexed: 11/16/2022] Open
Abstract
Approaches are sought after to regulate ionotropic and chronotropic properties of the mammalian heart. Electrodes are commonly used for rapidly exciting cardiac tissue and resetting abnormal pacing. With the advent of optogenetics and the use of tissue-specific expression of light-activated channels, cardiac cells cannot only be excited but also inhibited with ion-selective conductance. As a proof of concept for the ability to slow down cardiac pacing, anion-conducting channelrhodopsins (GtACR1/2) and the anion pump halorhodopsin (eNpHR) were expressed in hearts of larval Drosophila and activated by light. Unlike body wall muscles in most animals, the equilibrium potential for Cl− is more positive as compared to the resting membrane potential in larval Drosophila. As a consequence, upon activating the two forms of GtACR1 and 2 with low light intensity the heart rate increased, likely due to depolarization and opening of voltage-gated Ca2+ channels. However, with very intense light activation the heart rate ceases, which may be due to Cl– shunting to the reversal potential for chloride. Activating eNpHR hyperpolarizes body wall and cardiac muscle in larval Drosophila and rapidly decreases heart rate. The decrease in heart rate is related to light intensity. Intense light activation of eNpHR stops the heart from beating, whereas lower intensities slowed the rate. Even with upregulation of the heart rate with serotonin, the pacing of the heart was slowed with light. Thus, regulation of the heart rate in Drosophila can be accomplished by activating anion-conducting channelrhodopsins using light. These approaches are demonstrated in a genetically amenable insect model.
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Affiliation(s)
- Catherine E Stanley
- Department of Biology, Center for Muscle Biology. University of Kentucky, Lexington, KY 40506-0225, USA
| | - Alex S Mauss
- Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Alexander Borst
- Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Robin L Cooper
- Department of Biology, Center for Muscle Biology. University of Kentucky, Lexington, KY 40506-0225, USA.
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29
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Dong R, Mu-u-min R, Reith AJM, O’Shea C, He S, Duan K, Kou K, Grassam-Rowe A, Tan X, Pavlovic D, Ou X, Lei M. A Protocol for Dual Calcium-Voltage Optical Mapping in Murine Sinoatrial Preparation With Optogenetic Pacing. Front Physiol 2019; 10:954. [PMID: 31456689 PMCID: PMC6698704 DOI: 10.3389/fphys.2019.00954] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 07/09/2019] [Indexed: 01/08/2023] Open
Abstract
Among the animal models for studying the molecular basis of atrial and sinoatrial node (SAN) biology and disease, the mouse is a widely used species due to its feasibility for genetic modifications in genes encoding ion channels or calcium handling and signaling proteins in the heart. It is therefore highly valuable to develop robust methodologies for studying SAN and atrial electrophysiological function in this species. Here, we describe a protocol for performing dual calcium-voltage optical mapping on mouse sinoatrial preparation (SAP), in combination with an optogenetic approach, for studying SAP membrane potential, intracellular Ca2+ transients, and pacemaker activity. The protocol includes the details for preparing the intact SAP, robust tissue dual-dye loading, light-programmed pacing, and high-resolution optical mapping. Our protocol provides an example of use of the combination of optogenetic and optical mapping techniques for investigating SAP membrane potential and intracellular Ca2+ transients and pacemaker activity with high temporal and spatial resolution in specific cardiac tissues. Thus, our protocol provides a useful tool for studying SAP physiology and pathophysiology in mice.
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Affiliation(s)
- Ruirui Dong
- 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
| | - Razik Mu-u-min
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | | | - Christopher O’Shea
- Institute for Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Shicheng He
- 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
| | - Kaizhong Duan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Kun Kou
- 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
| | | | - Xiaoqiu Tan
- 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
| | - Davor Pavlovic
- Institute for Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Xianhong Ou
- 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
| | - Ming Lei
- 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
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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