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Nyman M, Stølen TO, Johnsen AB, Garten K, Burton FL, Smith GL, Loennechen JP. A comprehensive protocol combining in vivo and ex vivo electrophysiological experiments in an arrhythmogenic animal model. Am J Physiol Heart Circ Physiol 2024; 326:H203-H215. [PMID: 37975708 PMCID: PMC11213483 DOI: 10.1152/ajpheart.00358.2023] [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: 06/20/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023]
Abstract
Ventricular arrhythmias contribute significantly to cardiovascular mortality, with coronary artery disease as the predominant underlying cause. Understanding the mechanisms of arrhythmogenesis is essential to identify proarrhythmic factors and develop novel approaches for antiarrhythmic prophylaxis and treatment. Animal models are vital in basic research on cardiac arrhythmias, encompassing molecular, cellular, ex vivo whole heart, and in vivo models. Most studies use either in vivo protocols lacking important information on clinical relevance or exclusively ex vivo protocols, thereby missing the opportunity to explore underlying mechanisms. Consequently, interpretation may be difficult due to dissimilarities in animal models, interventions, and individual properties across animals. Moreover, proarrhythmic effects observed in vivo are often not replicated in corresponding ex vivo preparations during mechanistic studies. We have established a protocol to perform both an in vivo and ex vivo electrophysiological characterization in an arrhythmogenic rat model with heart failure following myocardial infarction. The same animal is followed throughout the experiment. In vivo methods involve intracardiac programmed electrical stimulation and external defibrillation to terminate sustained ventricular arrhythmia. Ex vivo methods conducted on the Langendorff-perfused heart include an electrophysiological study with optical mapping of regional action potentials, conduction velocities, and dispersion of electrophysiological properties. By exploring the retention of the in vivo proarrhythmic phenotype ex vivo, we aim to examine whether the subsequent ex vivo detailed measurements are relevant to in vivo pathological behavior. This protocol can enhance greater understanding of cardiac arrhythmias by providing a standardized, yet adaptable model for evaluating arrhythmogenicity or antiarrhythmic interventions in cardiac diseases.NEW & NOTEWORTHY Rodent models are widely used in arrhythmia research. However, most studies do not standardize clinically relevant in vivo and ex vivo techniques to support their conclusions. Here, we present a comprehensive electrophysiological protocol in an arrhythmogenic rat model, connecting in vivo and ex vivo programmed electrical stimulation with optical mapping. By establishing this protocol, we aim to facilitate the adoption of a standardized model for investigating arrhythmias, enhancing research rigor and comparability in this field.
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Affiliation(s)
- Mathias Nyman
- Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
- Clinic of Cardiology, St. Olavs University Hospital, Trondheim, Norway
| | - Tomas O Stølen
- Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Anne Berit Johnsen
- Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Karin Garten
- Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Francis L Burton
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Godfrey L Smith
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Jan Pål Loennechen
- Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
- Clinic of Cardiology, St. Olavs University Hospital, Trondheim, Norway
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2
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Müllenbroich MC, Kelly A, Acker C, Bub G, Bruegmann T, Di Bona A, Entcheva E, Ferrantini C, Kohl P, Lehnart SE, Mongillo M, Parmeggiani C, Richter C, Sasse P, Zaglia T, Sacconi L, Smith GL. Novel Optics-Based Approaches for Cardiac Electrophysiology: A Review. Front Physiol 2021; 12:769586. [PMID: 34867476 PMCID: PMC8637189 DOI: 10.3389/fphys.2021.769586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/18/2021] [Indexed: 12/31/2022] Open
Abstract
Optical techniques for recording and manipulating cellular electrophysiology have advanced rapidly in just a few decades. These developments allow for the analysis of cardiac cellular dynamics at multiple scales while largely overcoming the drawbacks associated with the use of electrodes. The recent advent of optogenetics opens up new possibilities for regional and tissue-level electrophysiological control and hold promise for future novel clinical applications. This article, which emerged from the international NOTICE workshop in 2018, reviews the state-of-the-art optical techniques used for cardiac electrophysiological research and the underlying biophysics. The design and performance of optical reporters and optogenetic actuators are reviewed along with limitations of current probes. The physics of light interaction with cardiac tissue is detailed and associated challenges with the use of optical sensors and actuators are presented. Case studies include the use of fluorescence recovery after photobleaching and super-resolution microscopy to explore the micro-structure of cardiac cells and a review of two photon and light sheet technologies applied to cardiac tissue. The emergence of cardiac optogenetics is reviewed and the current work exploring the potential clinical use of optogenetics is also described. Approaches which combine optogenetic manipulation and optical voltage measurement are discussed, in terms of platforms that allow real-time manipulation of whole heart electrophysiology in open and closed-loop systems to study optimal ways to terminate spiral arrhythmias. The design and operation of optics-based approaches that allow high-throughput cardiac electrophysiological assays is presented. Finally, emerging techniques of photo-acoustic imaging and stress sensors are described along with strategies for future development and establishment of these techniques in mainstream electrophysiological research.
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Affiliation(s)
| | - Allen Kelly
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Corey Acker
- Center for Cell Analysis and Modeling, UConn Health, Farmington, CT, United States
| | - Gil Bub
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Tobias Bruegmann
- Institute for Cardiovascular Physiology, University Medical Center Goettingen, Goettingen, Germany
| | - Anna Di Bona
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padova, Italy
| | - Emilia Entcheva
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | | | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Stephan E. Lehnart
- Heart Research Center Göttingen, University Medical Center Göttingen, Göttingen, Germany
- Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | | | - Claudia Richter
- German Primate Center - Leibniz Institute for Primate Research, Göttingen, Germany
| | - Philipp Sasse
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Leonardo Sacconi
- European Laboratory for Nonlinear Spectroscopy, Sesto Fiorentino, Italy
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
- National Institute of Optics, National Research Council, Florence, Italy
| | - Godfrey L. Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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3
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Ratiometric two-photon fluorescence probes for sensing, imaging and biomedicine applications at living cell and small animal levels. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214114] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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4
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Two-photon excitation of FluoVolt allows improved interrogation of transmural electrophysiological function in the intact mouse heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 154:11-20. [PMID: 31492464 PMCID: PMC7322535 DOI: 10.1016/j.pbiomolbio.2019.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/17/2019] [Accepted: 08/15/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND & AIMS Two-photon excitation of voltage sensitive dyes (VSDs) can measure rapidly changing electrophysiological signals deep within intact cardiac tissue with improved three-dimensional resolution along with reduced photobleaching and photo-toxicity compared to conventional confocal microscopy. Recently, a category of VSDs has emerged which records membrane potentials by photo-induced electron transfer. FluoVolt is a novel VSD in this category which promises fast response and a 25% fractional change in fluorescence per 100 mV, making it an attractive optical probe for action potential (AP) recordings within intact cardiac tissue. The purpose of this study was to characterize the fluorescent properties of FluoVolt as well as its utility for deep tissue imaging. METHODS Discrete tissue layers throughout the left ventricular wall of isolated perfused murine hearts loaded with FluoVolt or di-4-ANEPPS were sequentially excited with two-photon microscopy. RESULTS FluoVolt loaded hearts suffered significantly fewer episodes of atrio-ventricular block compared to di-4-ANEPPS loaded hearts, indicating comparatively low toxicity of FluoVolt in the intact heart. APs recorded with FluoVolt were characterized by a lower signal-to-noise ratio and a higher dynamic range compared to APs recorded with di-4-ANEPPS. Although both depolarization and repolarization parameters were similar in APs recorded with either dye, FluoVolt allowed deeper tissue excitation with improved three-dimensional resolution due to reduced out-of-focus fluorescence generation under two-photon excitation. CONCLUSION Our results demonstrate several advantages of two-photon excitation of FluoVolt in functional studies in intact heart preparations, including reduced toxicity and improved fluorescent properties.
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Kelly A, Salerno S, Connolly A, Bishop M, Charpentier F, Stølen T, Smith GL. Normal interventricular differences in tissue architecture underlie right ventricular susceptibility to conduction abnormalities in a mouse model of Brugada syndrome. Cardiovasc Res 2019; 114:724-736. [PMID: 29267949 PMCID: PMC5915948 DOI: 10.1093/cvr/cvx244] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/16/2017] [Indexed: 01/09/2023] Open
Abstract
Aims Loss-of-function of the cardiac sodium channel NaV1.5 is a common feature of Brugada syndrome. Arrhythmias arise preferentially from the right ventricle (RV) despite equivalent NaV1.5 downregulation in the left ventricle (LV). The reasons for increased RV sensitivity to NaV1.5 loss-of-function mutations remain unclear. Because ventricular electrical activation occurs predominantly in the transmural axis, we compare RV and LV transmural electrophysiology to determine the underlying cause of the asymmetrical conduction abnormalities in Scn5a haploinsufficient mice (Scn5a+/−). Methods and results Optical mapping and two-photon microscopy in isolated-perfused mouse hearts demonstrated equivalent depression of transmural conduction velocity (CV) in the LV and RV of Scn5a+/− vs. wild-type littermates. Only RV transmural conduction was further impaired when challenged with increased pacing frequencies. Epicardial dispersion of activation and beat-to-beat variation in activation time were increased only in the RV of Scn5a+/− hearts. Analysis of confocal and histological images revealed larger intramural clefts between cardiomyocyte layers in the RV vs. LV, independent of genotype. Acute sodium current inhibition in wild type hearts using tetrodotoxin reproduced beat-to-beat activation variability and frequency-dependent CV slowing in the RV only, with the LV unaffected. The influence of clefts on conduction was examined using a two-dimensional monodomain computational model. When peak sodium channel conductance was reduced to 50% of normal the presence of clefts between cardiomyocyte layers reproduced the activation variability and conduction phenotype observed experimentally. Conclusions Normal structural heterogeneities present in the RV are responsible for increased vulnerability to conduction slowing in the presence of reduced sodium channel function. Heterogeneous conduction slowing seen in the RV will predispose to functional block and the initiation of re-entrant ventricular arrhythmias.
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Affiliation(s)
- Allen Kelly
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway.,Institute of Cardiovascular & Medical Sciences, University of Glasgow G12 8QQ, UK
| | - Simona Salerno
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway
| | - Adam Connolly
- Division of Imaging Sciences and Biomedical Engineering, Department of Biomedical Engineering, Kings College London SE1 7EH, UK
| | - Martin Bishop
- Division of Imaging Sciences and Biomedical Engineering, Department of Biomedical Engineering, Kings College London SE1 7EH, UK
| | | | - Tomas Stølen
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway
| | - Godfrey L Smith
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway.,Institute of Cardiovascular & Medical Sciences, University of Glasgow G12 8QQ, UK
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6
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Ghouri IA, Kelly A, Salerno S, Garten K, Stølen T, Kemi1 OJ, Smith GL. Characterization of Electrical Activity in Post-myocardial Infarction Scar Tissue in Rat Hearts Using Multiphoton Microscopy. Front Physiol 2018; 9:1454. [PMID: 30386255 PMCID: PMC6199960 DOI: 10.3389/fphys.2018.01454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/25/2018] [Indexed: 11/13/2022] Open
Abstract
Background: The origin of electrical behavior in post-myocardial infarction scar tissue is still under debate. This study aims to examine the extent and nature of the residual electrical activity within a stabilized ventricular infarct scar. Methods and Results: An apical infarct was induced in the left ventricle of Wistar rats by coronary artery occlusion. Five weeks post-procedure, hearts were Langendorff-perfused, and optically mapped using di-4-ANEPPS. Widefield imaging of optical action potentials (APs) on the left ventricular epicardial surface revealed uniform areas of electrical activity in both normal zone (NZ) and infarct border zone (BZ), but only limited areas of low-amplitude signals in the infarct zone (IZ). 2-photon (2P) excitation of di-4-ANEPPS and Fura-2/AM at discrete layers in the NZ revealed APs and Ca2+ transients (CaTs) to 500-600 μm below the epicardial surface. 2P imaging in the BZ revealed superficial connective tissue structures lacking APs or CaTs. At depths greater than approximately 300 μm, myocardial structures were evident that supported normal APs and CaTs. In the IZ, although 2P imaging did not reveal clear myocardial structures, low-amplitude AP signals were recorded at discrete layers. No discernible Ca2+ signals could be detected in the IZ. AP rise times in BZ were slower than NZ (3.50 ± 0.50 ms vs. 2.23 ± 0.28 ms) and further slowed in IZ (9.13 ± 0.56 ms). Widefield measurements of activation delay between NZ and BZ showed negligible difference (3.37 ± 1.55 ms), while delay values in IZ showed large variation (11.88 ± 9.43 ms). Conclusion: These AP measurements indicate that BZ consists of an electrically inert scar above relatively normal myocardium. Discrete areas/layers of IZ displayed entrained APs with altered electrophysiology, but the structure of this tissue remains to be elucidated.
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Affiliation(s)
- Iffath A. Ghouri
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Allen Kelly
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Simona Salerno
- Department of Circulation and Medical Imaging, St. Olav’s Hospital, Norwegian University of Science and Technology, Trondheim, Norway
| | - Karin Garten
- Department of Circulation and Medical Imaging, St. Olav’s Hospital, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tomas Stølen
- Department of Circulation and Medical Imaging, St. Olav’s Hospital, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ole-Johan Kemi1
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Godfrey L. Smith
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, United Kingdom,*Correspondence: Godfrey L. Smith,
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7
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Jones JS, Small DM, Nishimura N. In Vivo Calcium Imaging of Cardiomyocytes in the Beating Mouse Heart With Multiphoton Microscopy. Front Physiol 2018; 9:969. [PMID: 30108510 PMCID: PMC6079295 DOI: 10.3389/fphys.2018.00969] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 07/02/2018] [Indexed: 12/22/2022] Open
Abstract
Background: Understanding the microscopic dynamics of the beating heart has been challenging due to the technical nature of imaging with micrometer resolution while the heart moves. The development of multiphoton microscopy has made in vivo, cell-resolved measurements of calcium dynamics and vascular function possible in motionless organs such as the brain. In heart, however, studies of in vivo interactions between cells and the native microenvironment are behind other organ systems. Our goal was to develop methods for intravital imaging of cardiac structural and calcium dynamics with microscopic resolution. Methods: Ventilated mice expressing GCaMP6f, a genetically encoded calcium indicator, received a thoracotomy to provide optical access to the heart. Vasculature was labeled with an injection of dextran-labeled dye. The heart was partially stabilized by a titanium probe with a glass window. Images were acquired at 30 frames per second with spontaneous heartbeat and continuously running, ventilated breathing. The data were reconstructed into three-dimensional volumes showing tissue structure, vasculature, and GCaMP6f signal in cardiomyocytes as a function of both the cardiac and respiratory cycle. Results: We demonstrated the capability to simultaneously measure calcium transients, vessel size, and tissue displacement in three dimensions with micrometer resolution. Reconstruction at various combinations of cardiac and respiratory phase enabled measurement of regional and single-cell cardiomyocyte calcium transients (GCaMP6f fluorescence). GCaMP6f fluorescence transients in individual, aberrantly firing cardiomyocytes were also quantified. Comparisons of calcium dynamics (rise-time and tau) at varying positions within the ventricle wall showed no significant depth dependence. Conclusion: This method enables studies of coupling between contraction and excitation during physiological blood perfusion and breathing at high spatiotemporal resolution. These capabilities could lead to a new understanding of normal and disease function of cardiac cells.
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Affiliation(s)
- Jason S Jones
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - David M Small
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Nozomi Nishimura
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
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Weinberger F, Breckwoldt K, Pecha S, Kelly A, Geertz B, Starbatty J, Yorgan T, Cheng KH, Lessmann K, Stolen T, Scherrer-Crosbie M, Smith G, Reichenspurner H, Hansen A, Eschenhagen T. Cardiac repair in guinea pigs with human engineered heart tissue from induced pluripotent stem cells. Sci Transl Med 2017; 8:363ra148. [PMID: 27807283 DOI: 10.1126/scitranslmed.aaf8781] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 09/19/2016] [Indexed: 12/16/2022]
Abstract
Myocardial injury results in a loss of contractile tissue mass that, in the absence of efficient regeneration, is essentially irreversible. Transplantation of human pluripotent stem cell-derived cardiomyocytes has beneficial but variable effects. We created human engineered heart tissue (hEHT) strips from human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and hiPSC-derived endothelial cells. The hEHTs were transplanted onto large defects (22% of the left ventricular wall, 35% decline in left ventricular function) of guinea pig hearts 7 days after cryoinjury, and the results were compared with those obtained with human endothelial cell patches (hEETs) or cell-free patches. Twenty-eight days after transplantation, the hearts repaired with hEHT strips exhibited, within the scar, human heart muscle grafts, which had remuscularized 12% of the infarct area. These grafts showed cardiomyocyte proliferation, vascularization, and evidence for electrical coupling to the intact heart tissue in a subset of engrafted hearts. hEHT strips improved left ventricular function by 31% compared to that before implantation, whereas the hEET or cell-free patches had no effect. Together, our study demonstrates that three-dimensional human heart muscle constructs can repair the injured heart.
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Affiliation(s)
- Florian Weinberger
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Kaja Breckwoldt
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Simon Pecha
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany.,Department of Cardiovascular Surgery, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Allen Kelly
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7030 Trondheim, Norway.,Norwegian Council on Cardiovascular Disease, Oslo, Norway
| | - Birgit Geertz
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Jutta Starbatty
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Timur Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Kai-Hung Cheng
- Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Katrin Lessmann
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Tomas Stolen
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7030 Trondheim, Norway.,Norwegian Council on Cardiovascular Disease, Oslo, Norway
| | | | - Godfrey Smith
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7030 Trondheim, Norway.,Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - Hermann Reichenspurner
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany.,Department of Cardiovascular Surgery, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Arne Hansen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany. .,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
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Krafft C. Modern trends in biophotonics for clinical diagnosis and therapy to solve unmet clinical needs. JOURNAL OF BIOPHOTONICS 2016; 9:1362-1375. [PMID: 27943650 DOI: 10.1002/jbio.201600290] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
This contribution covers recent original research papers in the biophotonics field. The content is organized into main techniques such as multiphoton microscopy, Raman spectroscopy, infrared spectroscopy, optical coherence tomography and photoacoustic tomography, and their applications in the context of fluid, cell, tissue and skin diagnostics. Special attention is paid to vascular and blood flow diagnostics, photothermal and photodynamic therapy, tissue therapy, cell characterization, and biosensors for biomarker detection.
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Affiliation(s)
- Christoph Krafft
- Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745, Jena, Germany
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10
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Tanaka A, Kawaji K, Patel AR, Ota T. The extracellular matrix patch implanted in the right ventricle evaluated with cardiovascular magnetic resonance protocol to assess regional physio-mechanical properties. Interact Cardiovasc Thorac Surg 2016; 24:82-89. [PMID: 27624357 DOI: 10.1093/icvts/ivw296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 06/23/2016] [Accepted: 07/25/2016] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVES An extracellular matrix patch was implanted in the porcine right ventricle for in situ myocardial regeneration. A newly developed cardiovascular magnetic resonance protocol was utilized to investigate the regional physio-mechanical function of the patch. METHODS Cardiovascular magnetic resonance was performed at 60-day after the porcine right ventricular wall full thickness substitution with an extracellular matrix cardiac patch (n = 5). Dacron patches and remote normal right ventricle served as control (n = 5/each). Late gadolinium enhancement, strain encoding and rest perfusion were measured for scar/patch detection, regional contractility and tissue perfusion. Image analyses were performed by two observers to validate interobserver reproducibility. RESULTS All imaging sequences were successfully obtained. The patches were located with late gadolinium enhancement imaging in 95% accuracy. All the parameters demonstrated significant differences among extracellular matrix, Dacron and normal myocardium (P < 0.05), which correlated with histological findings, including constructive remodelling with nascent myocardium and profound vasculogenesis/angiogenesis in extracellular matrix patches, and scar formation in Dacron. Bland-Altman analysis demonstrated good interobserver reproducibility with minimal bias (strain encoding/peak strain: mean difference = -0.32%, 95% limits of agreement = -1.2 to 0.57, correlation = 0.97; rest perfusion/relative maximum upslope: mean difference = -0.74, 95% limits of agreement = -2.0 to 0.53, correlation = 0.92), along with excellent correlation obtained from linear regression (strain encoding: R2 = 0.93; rest perfusion: R2 = 0.85). CONCLUSIONS With the cardiovascular magnetic resonance protocol, we successfully confirmed early signs of functional myocardial regeneration in implanted extracellular matrix patches. This approach is promising in assessing in situ regional physio-mechanical properties and degree of regeneration of implanted tissue-engineered materials.
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Affiliation(s)
- Akiko Tanaka
- Section of Cardiac and Thoracic Surgery, Department of Surgery, The University of Chicago, Chicago, IL, USA
| | - Keigo Kawaji
- Section of Cardiology, Department of Medicine, The University of Chicago, Chicago, IL, USA
| | - Amit R Patel
- Section of Cardiology, Department of Medicine, The University of Chicago, Chicago, IL, USA
| | - Takeyoshi Ota
- Section of Cardiac and Thoracic Surgery, Department of Surgery, The University of Chicago, Chicago, IL, USA
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11
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Szymanska AF, Heylman C, Datta R, Gratton E, Nenadic Z. Automated detection and analysis of depolarization events in human cardiomyocytes using MaDEC. Comput Biol Med 2016; 75:109-17. [PMID: 27281718 DOI: 10.1016/j.compbiomed.2016.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/17/2016] [Accepted: 05/20/2016] [Indexed: 11/16/2022]
Abstract
Optical imaging-based methods for assessing the membrane electrophysiology of in vitro human cardiac cells allow for non-invasive temporal assessment of the effect of drugs and other stimuli. Automated methods for detecting and analyzing the depolarization events (DEs) in image-based data allow quantitative assessment of these different treatments. In this study, we use 2-photon microscopy of fluorescent voltage-sensitive dyes (VSDs) to capture the membrane voltage of actively beating human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs). We built a custom and freely available Matlab software, called MaDEC, to detect, quantify, and compare DEs of hiPS-CMs treated with the β-adrenergic drugs, propranolol and isoproterenol. The efficacy of our software is quantified by comparing detection results against manual DE detection by expert analysts, and comparing DE analysis results to known drug-induced electrophysiological effects. The software accurately detected DEs with true positive rates of 98-100% and false positive rates of 1-2%, at signal-to-noise ratios (SNRs) of 5 and above. The MaDEC software was also able to distinguish control DEs from drug-treated DEs both immediately as well as 10min after drug administration.
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Affiliation(s)
- Agnieszka F Szymanska
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA.
| | - Christopher Heylman
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Rupsa Datta
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Zoran Nenadic
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
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Supervised Machine Learning for Classification of the Electrophysiological Effects of Chronotropic Drugs on Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. PLoS One 2015; 10:e0144572. [PMID: 26695765 PMCID: PMC4690607 DOI: 10.1371/journal.pone.0144572] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 11/22/2015] [Indexed: 12/21/2022] Open
Abstract
Supervised machine learning can be used to predict which drugs human cardiomyocytes have been exposed to. Using electrophysiological data collected from human cardiomyocytes with known exposure to different drugs, a supervised machine learning algorithm can be trained to recognize and classify cells that have been exposed to an unknown drug. Furthermore, the learning algorithm provides information on the relative contribution of each data parameter to the overall classification. Probabilities and confidence in the accuracy of each classification may also be determined by the algorithm. In this study, the electrophysiological effects of β-adrenergic drugs, propranolol and isoproterenol, on cardiomyocytes derived from human induced pluripotent stem cells (hiPS-CM) were assessed. The electrophysiological data were collected using high temporal resolution 2-photon microscopy of voltage sensitive dyes as a reporter of membrane voltage. The results demonstrate the ability of our algorithm to accurately assess, classify, and predict hiPS-CM membrane depolarization following exposure to chronotropic drugs.
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13
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Gautam V, Drury J, Choy JMC, Stricker C, Bachor HA, Daria VR. Improved two-photon imaging of living neurons in brain tissue through temporal gating. BIOMEDICAL OPTICS EXPRESS 2015; 6:4027-36. [PMID: 26504651 PMCID: PMC4605060 DOI: 10.1364/boe.6.004027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/11/2015] [Accepted: 09/11/2015] [Indexed: 05/05/2023]
Abstract
We optimize two-photon imaging of living neurons in brain tissue by temporally gating an incident laser to reduce the photon flux while optimizing the maximum fluorescence signal from the acquired images. Temporal gating produces a bunch of ~10 femtosecond pulses and the fluorescence signal is improved by increasing the bunch-pulse energy. Gating is achieved using an acousto-optic modulator with a variable gating frequency determined as integral multiples of the imaging sampling frequency. We hypothesize that reducing the photon flux minimizes the photo-damage to the cells. Our results, however, show that despite producing a high fluorescence signal, cell viability is compromised when the gating and sampling frequencies are equal (or effectively one bunch-pulse per pixel). We found an optimum gating frequency range that maintains the viability of the cells while preserving a pre-set fluorescence signal of the acquired two-photon images. The neurons are imaged while under whole-cell patch, and the cell viability is monitored as a change in the membrane's input resistance.
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Affiliation(s)
- Vini Gautam
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Jack Drury
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Julian M. C. Choy
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Christian Stricker
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
- Medical School, The Australian National University, Canberra, ACT 2601, Australia
| | - Hans-A. Bachor
- Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
| | - Vincent R. Daria
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
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14
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Lu XL, Rubart M. Micron-scale voltage and [Ca(2+)]i imaging in the intact heart. Front Physiol 2014; 5:451. [PMID: 25520663 PMCID: PMC4251286 DOI: 10.3389/fphys.2014.00451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 11/03/2014] [Indexed: 12/03/2022] Open
Abstract
Studies in isolated cardiomyocytes have provided tremendous information at the cellular and molecular level concerning regulation of transmembrane voltage (Vm) and intracellular calcium ([Ca2+]i). The ability to use the information gleaned to gain insight into the function of ion channels and Ca2+ handling proteins in a more complex system, e.g., the intact heart, has remained a challenge. We have developed laser scanning fluorescence microscopy-based approaches to monitor, at the sub-cellular to multi-cellular level in the immobilized, Langendorff-perfused mouse heart, dynamic changes in [Ca2+]i and Vm. This article will review the use of single- or dual-photon laser scanning microscopy [Ca2+]i imaging in conjunction with transgenic reporter technology to (a) interrogate the extent to which transplanted, donor-derived myocytes or cardiac stem cell-derived de novo myocytes are capable of forming a functional syncytium with the pre-existing myocardium, using entrainment of [Ca2+]i transients by the electrical activity of the recipient heart as a surrogate for electrical coupling, and (b) characterize the Ca2+ handling phenotypes of cellular implants. Further, we will review the ability of laser scanning fluorescence microscopy in conjunction with a fast-response voltage-sensitive to resolve, on a subcellular level in Langendorff-perfused mouse hearts, Vm dynamics that typically occur during the course of a cardiac action potential. Specifically, the utility of this technique to measure microscopic-scale voltage gradients in the normal and diseased heart is discussed.
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Affiliation(s)
- Xiao-Long Lu
- Riley Heart Research Center, Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine Indianapolis, IN, USA
| | - Michael Rubart
- Riley Heart Research Center, Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine Indianapolis, IN, USA
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