1
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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: 33] [Impact Index Per Article: 16.5] [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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2
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Smith RD, Kolb I, Tanaka S, Lee AK, Harris TD, Barbic M. Robotic multi-probe single-actuator inchworm neural microdrive. eLife 2022; 11:71876. [PMID: 36355598 PMCID: PMC9651949 DOI: 10.7554/elife.71876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/13/2022] [Indexed: 11/11/2022] Open
Abstract
A wide range of techniques in neuroscience involve placing individual probes at precise locations in the brain. However, large-scale measurement and manipulation of the brain using such methods have been severely limited by the inability to miniaturize systems for probe positioning. Here, we present a fundamentally new, remote-controlled micropositioning approach composed of novel phase-change material-filled resistive heater micro-grippers arranged in an inchworm motor configuration. The microscopic dimensions, stability, gentle gripping action, individual electronic control, and high packing density of the grippers allow micrometer-precision independent positioning of many arbitrarily shaped probes using a single piezo actuator. This multi-probe single-actuator design significantly reduces the size and weight and allows for potential automation of microdrives. We demonstrate accurate placement of multiple electrodes into the rat hippocampus in vivo in acute and chronic preparations. Our robotic microdrive technology should therefore enable the scaling up of many types of multi-probe applications in neuroscience and other fields.
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Affiliation(s)
| | - Ilya Kolb
- Janelia Research Campus, Howard Hughes Medical Institute
| | | | - Albert K Lee
- Janelia Research Campus, Howard Hughes Medical Institute
| | | | - Mladen Barbic
- Janelia Research Campus, Howard Hughes Medical Institute
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3
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Lin J, Abraham A, George SA, Greer-Short A, Blair GA, Moreno A, Alber BR, Kay MW, Poelzing S. Ephaptic Coupling Is a Mechanism of Conduction Reserve During Reduced Gap Junction Coupling. Front Physiol 2022; 13:848019. [PMID: 35600295 PMCID: PMC9117633 DOI: 10.3389/fphys.2022.848019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
Many cardiac pathologies are associated with reduced gap junction (GJ) coupling, an important modulator of cardiac conduction velocity (CV). However, the relationship between phenotype and functional expression of the connexin GJ family of proteins is controversial. For example, a 50% reduction of GJ coupling has been shown to have little impact on myocardial CV due to a concept known as conduction reserve. This can be explained by the ephaptic coupling (EpC) theory whereby conduction is maintained by a combination of low GJ coupling and increased electrical fields generated in the sodium channel rich clefts between neighboring myocytes. At the same time, low GJ coupling may also increase intracellular charge accumulation within myocytes, resulting in a faster transmembrane potential rate of change during depolarization (dV/dt_max) that maintains macroscopic conduction. To provide insight into the prevalence of these two phenomena during pathological conditions, we investigated the relationship between EpC and charge accumulation within the setting of GJ remodeling using multicellular simulations and companion perfused mouse heart experiments. Conduction along a fiber of myocardial cells was simulated for a range of GJ conditions. The model incorporated intercellular variations, including GJ coupling conductance and distribution, cell-to-cell separation in the intercalated disc (perinexal width—WP), and variations in sodium channel distribution. Perfused heart studies having conditions analogous to those of the simulations were performed using wild type mice and mice heterozygous null for the connexin gene Gja1. With insight from simulations, the relative contributions of EpC and charge accumulation on action potential parameters and conduction velocities were analyzed. Both simulation and experimental results support a common conclusion that low GJ coupling decreases and narrowing WP increases the rate of the AP upstroke when sodium channels are densely expressed at the ends of myocytes, indicating that conduction reserve is more dependent on EpC than charge accumulation during GJ uncoupling.
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Affiliation(s)
- Joyce Lin
- Department of Mathematics, California Polytechnic State University, San Luis Obispo, CA, United States
- *Correspondence: Joyce Lin, ; Steven Poelzing,
| | - Anand Abraham
- Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
| | - Sharon A. George
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States
| | - Amara Greer-Short
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States
| | - Grace A. Blair
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Translational Biology, Medicine and Health, Virginia Tech, Roanoke, VA, United States
| | - Angel Moreno
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Bridget R. Alber
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Matthew W. Kay
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Steven Poelzing
- Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States
- Translational Biology, Medicine and Health, Virginia Tech, Roanoke, VA, United States
- *Correspondence: Joyce Lin, ; Steven Poelzing,
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4
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Swift LM, Kay MW, Ripplinger CM, Posnack NG. Stop the beat to see the rhythm: excitation-contraction uncoupling in cardiac research. Am J Physiol Heart Circ Physiol 2021; 321:H1005-H1013. [PMID: 34623183 DOI: 10.1152/ajpheart.00477.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Optical mapping is an imaging technique that is extensively used in cardiovascular research, wherein parameter-sensitive fluorescent indicators are used to study the electrophysiology and excitation-contraction coupling of cardiac tissues. Despite many benefits of optical mapping, eliminating motion artifacts within the optical signals is a major challenge, as myocardial contraction interferes with the faithful acquisition of action potentials and intracellular calcium transients. As such, excitation-contraction uncoupling agents are frequently used to reduce signal distortion by suppressing contraction. When compared with other uncoupling agents, blebbistatin is the most frequently used, as it offers increased potency with minimal direct effects on cardiac electrophysiology. Nevertheless, blebbistatin may exert secondary effects on electrical activity, metabolism, and coronary flow, and the incorrect administration of blebbistatin to cardiac tissue can prove detrimental, resulting in erroneous interpretation of optical mapping results. In this "Getting It Right" perspective, we briefly review the literature regarding the use of blebbistatin in cardiac optical mapping experiments, highlight potential secondary effects of blebbistatin on cardiac electrical activity and metabolic demand, and conclude with the consensus of the authors on best practices for effectively using blebbistatin in optical mapping studies of cardiac tissue.
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Affiliation(s)
- Luther M Swift
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia.,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
| | - Matthew W Kay
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia
| | | | - Nikki Gillum Posnack
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia.,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia.,Department of Pediatrics, George Washington University, Washington, District of Columbia.,Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
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5
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Opfermann JD, Barbic M, Khrenov M, Guo S, Sarfaraz NR, Kang JU, Krieger A. A Novel Wax Based Piezo Actuator for Autonomous Deep Anterior Lamellar Keratoplasty (Piezo-DALK). PROCEEDINGS OF THE ... IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS. IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS 2021; 2021:757-764. [PMID: 38170110 PMCID: PMC10759147 DOI: 10.1109/iros51168.2021.9636153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
This paper reports the design and evaluation of a novel piezo based actuator for needle drive in autonomous Deep Anterior Lamellar Keratoplasty (piezo-DALK). The actuator weighs less than 8g and is 20mm × 20mm × 10.5mm in size, making it ideal for eye-mounted applications. Mean open loop positional deviation was 1.17 ± 3.15um, and system repeatability and accuracy were 17.16um and 18.33um, respectively. Stall force was found to vary linearly with the cooling cycle and the actuator achieved a maximum drive force of 3.98N. When simulating the DALK procedure in synthetic corneal tissue, the piezo-DALK achieved a penetration depth of 643.56um which was equivalent to 92.1% of the total corneal thickness. This correlated closely with our desired depth of 90% ± 5% and took 2.5 hours to achieve. This work represents the first eye mountable actuator capable of "Big Bubble" needle drive for autonomous DALK procedures.
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Affiliation(s)
- J D Opfermann
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21211 USA
| | - M Barbic
- Tech4Health Institute, NYU School of Medicine, New York, NY 10016 USA
| | - M Khrenov
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 USA
| | - S Guo
- Department of Electrical Engineering, Johns Hopkins University, Baltimore, MD 21211 USA
| | - N R Sarfaraz
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 USA
| | - J U Kang
- Department of Electrical Engineering, Johns Hopkins University, Baltimore, MD 21211 USA
| | - A Krieger
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21211 USA
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6
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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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7
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Miller JM, Meki MH, Ou Q, George SA, Gams A, Abouleisa RRE, Tang XL, Ahern BM, Giridharan GA, El-Baz A, Hill BG, Satin J, Conklin DJ, Moslehi J, Bolli R, Ribeiro AJS, Efimov IR, Mohamed TMA. Heart slice culture system reliably demonstrates clinical drug-related cardiotoxicity. Toxicol Appl Pharmacol 2020; 406:115213. [PMID: 32877659 DOI: 10.1016/j.taap.2020.115213] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 02/07/2023]
Abstract
The limited availability of human heart tissue and its complex cell composition are major limiting factors for the reliable testing of drug efficacy and toxicity. Recently, we developed functional human and pig heart slice biomimetic culture systems that preserve the viability and functionality of 300 μm heart slices for up to 6 days. Here, we tested the reliability of this culture system for testing the cardiotoxicity of anti-cancer drugs. We tested three anti-cancer drugs (doxorubicin, trastuzumab, and sunitinib) with known different mechanisms of cardiotoxicity at three concentrations and assessed the effect of these drugs on heart slice viability, structure, function and gene expression. Slices incubated with any of these drugs for 48 h showed diminished in viability as well as loss of cardiomyocyte structure and function. Mechanistically, RNA sequencing of doxorubicin-treated tissues demonstrated a significant downregulation of cardiac genes and upregulation of oxidative stress responses. Trastuzumab treatment downregulated cardiac muscle contraction-related genes consistent with its clinically known effect on cardiomyocytes. Interestingly, sunitinib treatment resulted in significant downregulation of angiogenesis-related genes, in line with its mechanism of action. Similar to hiPS-derived-cardiomyocytes, heart slices recapitulated the expected toxicity of doxorubicin and trastuzumab, however, slices were superior in detecting sunitinib cardiotoxicity and mechanism in the clinically relevant concentration range of 0.1-1 μM. These results indicate that heart slice culture models have the potential to become a reliable platform for testing and elucidating mechanisms of drug cardiotoxicity.
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Affiliation(s)
- Jessica M Miller
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA; Department of Bioengineering, University of Louisville, KY, USA
| | - Moustafa H Meki
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA; Department of Bioengineering, University of Louisville, KY, USA
| | - Qinghui Ou
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA
| | - Sharon A George
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - Anna Gams
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - Riham R E Abouleisa
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA
| | - Xian-Liang Tang
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA
| | - Brooke M Ahern
- Department of Physiology, University of Kentucky, KY, USA
| | | | - Ayman El-Baz
- Department of Bioengineering, University of Louisville, KY, USA
| | - Bradford G Hill
- Envirome Institute, Diabetes and Obesity Center, Department of Medicine, University of Louisville, KY, USA
| | - Jonathan Satin
- Department of Physiology, University of Kentucky, KY, USA
| | - Daniel J Conklin
- Envirome Institute, Diabetes and Obesity Center, Department of Medicine, University of Louisville, KY, USA
| | - Javid Moslehi
- Division of Cardiology, Cardio-Oncology Program, Vanderbilt University Medical Center, 2220 Pierce Avenue, Nashville, USA
| | - Roberto Bolli
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA
| | - Alexandre J S Ribeiro
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Translational Science, Office of Clinical Pharmacology, Division of Applied Regulatory Science, Silver Spring, MD, USA.
| | - Igor R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA.
| | - Tamer M A Mohamed
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, KY, USA; Department of Bioengineering, University of Louisville, KY, USA; Envirome Institute, Diabetes and Obesity Center, Department of Medicine, University of Louisville, KY, USA; Department of Pharmacology and Toxicology, University of Louisville, KY, USA; Institute of Cardiovascular Sciences, University of Manchester, UK; Faculty of Pharmacy, Zagazig University, Egypt.
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8
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Valero M, English DF. Head-mounted approaches for targeting single-cells in freely moving animals. J Neurosci Methods 2019; 326:108397. [DOI: 10.1016/j.jneumeth.2019.108397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/30/2019] [Accepted: 08/06/2019] [Indexed: 12/11/2022]
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9
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Hunt DL, Lai C, Smith RD, Lee AK, Harris TD, Barbic M. Multimodal in vivo brain electrophysiology with integrated glass microelectrodes. Nat Biomed Eng 2019; 3:741-753. [PMID: 30936430 DOI: 10.1038/s41551-019-0373-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 02/21/2019] [Indexed: 12/31/2022]
Abstract
Electrophysiology is the most used approach for the collection of functional data in basic and translational neuroscience, but it is typically limited to either intracellular or extracellular recordings. The integration of multiple physiological modalities for the routine acquisition of multimodal data with microelectrodes could be useful for biomedical applications, yet this has been challenging owing to incompatibilities of fabrication methods. Here, we present a suite of glass pipettes with integrated microelectrodes for the simultaneous acquisition of multimodal intracellular and extracellular information in vivo, electrochemistry assessments, and optogenetic perturbations of neural activity. We used the integrated devices to acquire multimodal signals from the CA1 region of the hippocampus in mice and rats, and show that these data can serve as ground-truth validation for the performance of spike-sorting algorithms. The microdevices are applicable for basic and translational neurobiology, and for the development of next-generation brain-machine interfaces.
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Affiliation(s)
- David L Hunt
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA.
| | - Chongxi Lai
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
| | - Richard D Smith
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
| | - Albert K Lee
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
| | - Timothy D Harris
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
| | - Mladen Barbic
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA.
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10
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Mačianskienė R, Martišienė I, Navalinskas A, Treinys R, Andriulė I, Jurevičius J. Mechanism of Action Potential Prolongation During Metabolic Inhibition in the Whole Rabbit Heart. Front Physiol 2018; 9:1077. [PMID: 30140239 PMCID: PMC6095129 DOI: 10.3389/fphys.2018.01077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/19/2018] [Indexed: 11/24/2022] Open
Abstract
Myocardial ischemia is associated with significant changes in action potential (AP) duration, which has a biphasic response to metabolic inhibition. Here, we investigated the mechanism of initial AP prolongation in whole Langendorff-perfused rabbit heart. We used glass microelectrodes to record APs transmurally. Simultaneously, optical AP, calcium transient (CaT), intracellular pH, and magnesium concentration changes were recorded using fluorescent dyes. The fluorescence signals were recorded using an EMCCD camera equipped with emission filters; excitation was induced by LEDs. We demonstrated that metabolic inhibition by carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) resulted in AP shortening preceded by an initial prolongation and that there were no important differences in the response throughout the wall of the heart and in the apical/basal direction. AP prolongation was reduced by blocking the ICaL and transient outward potassium current (Ito) with diltiazem (DTZ) and 4-aminopyridine (4-AP), respectively. FCCP, an uncoupler of oxidative phosphorylation, induced reductions in CaTs and intracellular pH and increased the intracellular Mg2+ concentration. In addition, resting potential depolarization was observed, clearly indicating a decrease in the inward rectifier K+ current (IK1) that can retard AP repolarization. Thus, we suggest that the main currents responsible for AP prolongation during metabolic inhibition are the ICaL, Ito, and IK1, the activities of which are modulated mainly by changes in intracellular ATP, calcium, magnesium, and pH.
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Affiliation(s)
- Regina Mačianskienė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Irma Martišienė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Antanas Navalinskas
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Rimantas Treinys
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Inga Andriulė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Jonas Jurevičius
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
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11
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Lindsey ML, Gray GA, Wood SK, Curran-Everett D. Statistical considerations in reporting cardiovascular research. Am J Physiol Heart Circ Physiol 2018; 315:H303-H313. [PMID: 30028200 PMCID: PMC6139626 DOI: 10.1152/ajpheart.00309.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The problem of inadequate statistical reporting is long standing and widespread in the biomedical literature, including in cardiovascular physiology. Although guidelines for reporting statistics have been available in clinical medicine for some time, there are currently no guidelines specific to cardiovascular physiology. To assess the need for guidelines, we determined the type and frequency of statistical tests and procedures currently used in the American Journal of Physiology-Heart and Circulatory Physiology. A PubMed search for articles published in the American Journal of Physiology-Heart and Circulatory Physiology between January 1, 2017, and October 6, 2017, provided a final sample of 146 articles evaluated for methods used and 38 articles for indepth analysis. The t-test and ANOVA accounted for 71% (212 of 300 articles) of the statistical tests performed. Of six categories of post hoc tests, Bonferroni and Tukey tests were used in 63% (62 of 98 articles). There was an overall lack in details provided by authors publishing in the American Journal of Physiology-Heart and Circulatory Physiology, and we compiled a list of recommended minimum reporting guidelines to aid authors in preparing manuscripts. Following these guidelines could substantially improve the quality of statistical reports and enhance data rigor and reproducibility.
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Affiliation(s)
- Merry L Lindsey
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi.,Research Service, G. V. (Sonny) Montgomery Veterans Affairs Medical Center , Jackson, Mississippi
| | - Gillian A Gray
- British Heart Foundation/University Centre for Cardiovascular Science, Edinburgh Medical School, University of Edinburgh , Edinburgh , United Kingdom
| | - Susan K Wood
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine , Columbia, South Carolina
| | - Douglas Curran-Everett
- Division of Biostatistics and Bioinformatics, National Jewish Health , Denver, Colorado.,Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Denver , Denver, Colorado
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