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Esposito C, Machado P, McDonald ME, Savage MP, Fischman D, Mehrotra P, Cohen IS, Ruggiero N, Walinsky P, Vishnevsky A, Dickie K, Davis M, Forsberg F, Dave JK. Evaluation of Intracardiac Pressures Using Subharmonic-aided Pressure Estimation with Sonazoid Microbubbles. Radiol Cardiothorac Imaging 2024; 6:e230153. [PMID: 38358329 PMCID: PMC10912883 DOI: 10.1148/ryct.230153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 12/13/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024]
Abstract
Purpose To investigate if the right ventricular (RV) systolic and left ventricular (LV) diastolic pressures can be obtained noninvasively using the subharmonic-aided pressure estimation (SHAPE) technique with Sonazoid microbubbles. Materials and Methods Individuals scheduled for a left and/or right heart catheterization were prospectively enrolled in this institutional review board-approved clinical trial from 2017 to 2020. A standard-of-care catheterization procedure was performed by advancing fluid-filled pressure catheters into the LV and aorta (n = 25) or RV (n = 22), and solid-state high-fidelity pressure catheters into the LV and aorta in a subset of participants (n = 18). Study participants received an infusion of Sonazoid microbubbles (GE HealthCare), and SHAPE data were acquired using a validated interface developed on a SonixTablet (BK Medical) US scanner, synchronously with the pressure catheter data. A conversion factor, derived using cuff-based pressure measurements with a SphygmoCor XCEL PWA (ATCOR) and subharmonic signal from the aorta, was used to convert the subharmonic signal into pressure values. Errors between the pressure measurements obtained using the SHAPE technique and pressure catheter were compared. Results The mean errors in pressure measurements obtained with the SHAPE technique relative to those of the fluid-filled pressure catheter were 1.6 mm Hg ± 1.5 [SD] (P = .85), 8.4 mm Hg ± 6.2 (P = .04), and 7.4 mm Hg ± 5.7 (P = .09) for RV systolic, LV minimum diastolic, and LV end-diastolic pressures, respectively. Relative to the measurements with the solid-state high-fidelity pressure catheter, the mean errors in LV minimum diastolic and LV end-diastolic pressures were 7.2 mm Hg ± 4.5 and 6.8 mm Hg ± 3.3 (P ≥ .44), respectively. Conclusion These results indicate that SHAPE with Sonazoid may have the potential to provide clinically relevant RV systolic and LV diastolic pressures. Keywords: Ultrasound-Contrast, Cardiac, Aorta, Left Ventricle, Right Ventricle ClinicalTrials.gov registration no.: NCT03245255 © RSNA, 2024.
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Affiliation(s)
- Cara Esposito
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Priscilla Machado
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Maureen E. McDonald
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Michael P. Savage
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - David Fischman
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Praveen Mehrotra
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Ira S. Cohen
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Nicholas Ruggiero
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Paul Walinsky
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Alec Vishnevsky
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Kristopher Dickie
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Marguerite Davis
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Flemming Forsberg
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Jaydev K. Dave
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
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Cohen IS, Robinson RB, Steinberg SF. Michael R. Rosen, MD (1938-2023). Heart Rhythm 2023; 20:791-792. [PMID: 37120288 DOI: 10.1016/j.hrthm.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 05/01/2023]
Affiliation(s)
- Ira S Cohen
- Department of Physiology and Biophysics, Stony Brook School of Medicine, Stony Brook, New York
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Zhao L, Xu X, Shi J, Zhang G, Cohen IS, Zou X, Cui J. Compounds specifically enhance I Ks by modulating VSD-pore coupling. Biophys J 2023; 122:386a. [PMID: 36783962 DOI: 10.1016/j.bpj.2022.11.2112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Lu Zhao
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Xianjin Xu
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Jingyi Shi
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Guohui Zhang
- Washington University in St. Louis, St. Louis, MO, USA
| | - Ira S Cohen
- Department of Physiology and Biophysics, State University of New York Stony Brook, Stony Brook, NY, USA
| | - Xiaoqin Zou
- Department of Physics, University of Missouri, Columbia, MO, USA; Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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Esposito C, Machado P, McDonald ME, Savage MP, Fischman D, Mehrotra P, Cohen IS, Ruggiero N, Walinsky P, Vishnevsky A, Dickie K, Davis M, Forsberg F, Dave JK. Noninvasive Evaluation of Cardiac Chamber Pressures Using Subharmonic-Aided Pressure Estimation With Definity Microbubbles. JACC Cardiovasc Imaging 2023; 16:224-235. [PMID: 36648035 DOI: 10.1016/j.jcmg.2022.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 08/04/2022] [Accepted: 09/16/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Noninvasive and accurate assessment of intracardiac pressures has remained an elusive goal of noninvasive cardiac imaging. OBJECTIVES The purpose of this study was to investigate if errors in intracardiac pressures obtained noninvasively using contrast microbubbles and the subharmonic-aided pressure estimation (SHAPE) technique are <5 mm Hg. METHODS In a nonrandomized institutional review board-approved clinical trial (NCT03243942), patients scheduled for a left-sided and/or right-sided heart catheterization procedure and providing written informed consent were included. A standard-of-care catheterization procedure was performed advancing clinically used pressure catheters into the left and/or right ventricles and/or the aorta. After pressure catheter placement, patients received an infusion of Definity microbubbles (n = 56; 2 vials diluted in 50 mL of saline; infusion rate: 4-10 mL/min) (Lantheus Medical Imaging). Then SHAPE data was acquired using a validated interface developed on a SonixTablet scanner (BK Medical Systems) synchronously with the pressure catheter data. A conversion factor (mm Hg/dB) was derived from SHAPE data and measurements with a SphygmoCor XCEL PWA device (ATCOR Medical) and was combined with SHAPE data from the left and/or the right ventricles to obtain clinically relevant systolic and diastolic ventricular pressures. RESULTS The mean value of absolute errors for left ventricular minimum and end diastolic pressures were 2.9 ± 2.0 and 1.7 ± 1.2 mm Hg (n = 26), respectively, and for right ventricular systolic pressures was 2.2 ± 1.5 mm Hg (n = 11). Two adverse events occurred during Definity infusion; both were resolved. CONCLUSIONS These results indicate that the SHAPE technique with Definity microbubbles is encouragingly efficacious for obtaining intracardiac pressures noninvasively and accurately. (Noninvasive, Subharmonic Intra-Cardiac Pressure Measurement; NCT03243942).
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Affiliation(s)
- Cara Esposito
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Priscilla Machado
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Maureen E McDonald
- Medical Imaging and Radiation Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael P Savage
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David Fischman
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Praveen Mehrotra
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ira S Cohen
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nicholas Ruggiero
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul Walinsky
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Alec Vishnevsky
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | | | - Marguerite Davis
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jaydev K Dave
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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Liu Y, Xu X, Gao J, Naffaa MM, Liang H, Shi J, Wang HZ, Yang ND, Hou P, Zhao W, White KM, Kong W, Dou A, Cui A, Zhang G, Cohen IS, Zou X, Cui J. Author Correction: A PIP 2 substitute mediates voltage sensor-pore coupling in KCNQ activation. Commun Biol 2022; 5:1396. [PMID: 36543893 PMCID: PMC9772332 DOI: 10.1038/s42003-022-04375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Yongfeng Liu
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Xianjin Xu
- grid.134936.a0000 0001 2162 3504Dalton Cardiovascular Research Center, Department of Physics and Astronomy, Department of Biochemistry, Institute for Data Science & Informatics, University of Missouri, Columbia, MO 65211 USA
| | - Junyuan Gao
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, and Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Moawiah M. Naffaa
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Hongwu Liang
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Jingyi Shi
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Hong Zhan Wang
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, and Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Nien-Du Yang
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Panpan Hou
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Wenshan Zhao
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Kelli McFarland White
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Wenjuan Kong
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Alex Dou
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Amy Cui
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Guohui Zhang
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Ira S. Cohen
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, and Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Xiaoqin Zou
- grid.134936.a0000 0001 2162 3504Dalton Cardiovascular Research Center, Department of Physics and Astronomy, Department of Biochemistry, Institute for Data Science & Informatics, University of Missouri, Columbia, MO 65211 USA
| | - Jianmin Cui
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
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Valiunas V, Gordon C, Valiuniene L, Devine D, Lin RZ, Cohen IS, Brink PR. Intercellular delivery of therapeutic oligonucleotides. J Drug Deliv Sci Technol 2022; 72:103404. [PMID: 36721641 PMCID: PMC9886232 DOI: 10.1016/j.jddst.2022.103404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
One promising approach to cancer therapeutics is to induce changes in gene expression that either reduce cancer cell proliferation or induce cancer cell death. Therefore, delivering oligonucleotides (siRNA/miRNA) that target specific genes or gene programs might have a potential therapeutic benefit. The aim of this study was to examine the potential of cell-based delivery of oligonucleotides to cancer cells via two naturally occurring intercellular pathways: gap junctions and vesicular/exosomal traffic. We utilized human mesenchymal stem cells (hMSCs) as delivery cells and chose to deliver in vitro two synthetic oligonucleotides, AllStars HS Cell Death siRNA and miR-16 mimic, as toxic (therapeutic) oligonucleotides targeting three cancer cell lines: prostate (PC3), pancreatic (PANC1) and cervical (HeLa). Both oligonucleotides dramatically reduced cell proliferation and/or induced cell death when transfected directly into target cells and delivery hMSCs. The delivery and target cells we chose express gap junction connexin 43 (Cx43) endogenously (PC3, PANC1, hMSC) or via stable transfection (HeLaCx43). Co-culture of hMSCs (transfected with either toxic oligonucleotide) with any of Cx43 expressing cancer cells induced target cell death (~20% surviving) or senescence (~85% proliferation reduction) over 96 hours. We eliminated gap junction-mediated delivery by using connexin deficient HeLaWT cells or knocking out endogenous Cx43 in PANC1 and PC3 cells via CRISPR/Cas9. Subsequently, all Cx43 deficient target cells co-cultured with the same toxic oligonucleotide loaded hMSCs proliferated, albeit at significantly slower rates, with cell number increasing on average ~2.2-fold (30% of control cells) over 96 hours. Our results show that both gap junction and vesicular/exosomal intercellular delivery pathways from hMSCs to target cancer cells deliver oligonucleotides and function to either induce cell death or significantly reduce their proliferation. Thus, hMSC-based cellular delivery is an effective method of delivering synthetic oligonucleotides that can significantly reduce tumor cell growth and should be further investigated as a possible approach to cancer therapy.
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Affiliation(s)
- Virginijus Valiunas
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Chris Gordon
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Laima Valiuniene
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Daniel Devine
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Ira S Cohen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
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Esposito C, Machado P, Cohen IS, Mehrotra P, Savage M, Fischman D, Davis M, Ruggiero N, Walinsky P, McDonald ME, Dickie K, Forsberg F, Dave JK. Comparing Central Aortic Pressures Obtained Using a SphygmoCor Device to Pressures Obtained Using a Pressure Catheter. Am J Hypertens 2022; 35:397-406. [PMID: 35079778 PMCID: PMC9088843 DOI: 10.1093/ajh/hpac010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/11/2022] [Accepted: 01/24/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND This study compared aortic pressures estimated using a SphygmoCor XCEL PWA device (ATCOR, Naperville, IL) noninvasively with aortic pressures obtained using pressure catheters during catheterization procedures and analyzed the impact of a linear-fit function on the estimated pressure values. METHODS One hundred and thirty-six patients scheduled for cardiac catheterization procedure were enrolled in IRB approved studies. Catheterization procedures were performed according to standard-of-care to acquire aortic pressure measurements. Immediately after the catheterization procedure with the pressure catheters removed, while the patients were still in the catheterization laboratory, central aortic pressures were estimated with the SphygmoCor device (using its inbuilt transfer function). The error between measured and estimated aortic pressures was evaluated using Bland-Altman analysis (n = 93). A linear-fit was performed between the measured and estimated pressures, and using the linear equation the error measurements were repeated. A bootstrap analysis was performed to test the generalizability of the linear-fit function. In a subset of cases (n = 13), central aortic pressure values were also obtained using solid-state high-fidelity catheters (Millar, Houston, TX), and the error measurements were repeated. RESULTS The magnitude of errors between the measured and estimated aortic pressures (mean errors >6.4 mm Hg; mean errors >8.0 mm Hg in the subset) were reduced to less than 1 mm Hg after using the linear-fit function derived in this study. CONCLUSIONS For the population examined in this study, the SphygmoCor data must be used with the linear-fit function to obtain aortic pressures that are comparable to the measurements obtained using pressure catheters. CLINICAL TRIALS REGISTRATION Trial Numbers NCT03243942 and NCT03245255.
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Affiliation(s)
- Cara Esposito
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Priscilla Machado
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ira S Cohen
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Praveen Mehrotra
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael Savage
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David Fischman
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Marguerite Davis
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nicholas Ruggiero
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul Walinsky
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Maureen E McDonald
- Department of Medical Imaging and Radiation Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | | | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Abstract
It has long been known that heart rate is regulated by the autonomic nervous system. Recently, we demonstrated that the pacemaker current, If, is regulated by phosphoinositide 3-kinase (PI3K) signaling independently of the autonomic nervous system. Inhibition of PI3K in sinus node (SN) myocytes shifts the activation of If by almost 16 mV in the negative direction. If in the SN is predominantly mediated by two members of the HCN gene family, HCN4 and HCN1. Purkinje fibers also possess If and are an important secondary pacemaker in the heart. In contrast to the SN, they express HCN2 and HCN4, while ventricular myocytes, which do not normally pace, express HCN2 alone. In the current work, we investigated PI3K regulation of HCN2 expressed in HEK293 cells. Treatment with the PI3K inhibitor PI-103 caused a negative shift in the activation voltage and a dramatic reduction in the magnitude of the HCN2 current. Similar changes were also seen in cells treated with an inhibitor of the protein kinase Akt, a downstream effector of PI3K. The effects of PI-103 were reversed by perfusion of cells with phosphatidylinositol 3,4,5-trisphosphate (the second messenger produced by PI3K) or active Akt protein. We identified serine 861 in mouse HCN2 as a putative Akt phosphorylation site. Mutation of S861 to alanine mimicked the effects of Akt inhibition on voltage dependence and current magnitude. In addition, the Akt inhibitor had no effect on the mutant channel. These results suggest that Akt phosphorylation of mHCN2 S861 accounts for virtually all of the observed actions of PI3K signaling on the HCN2 current. Unexpectedly, Akt inhibition had no effect on If in SN myocytes. This result raises the possibility that diverse PI3K signaling pathways differentially regulate HCN-induced currents in different tissues, depending on the isoforms expressed.
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Affiliation(s)
- Zhongju Lu
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States.,Department of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Hong Zhan Wang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States
| | - Chris R Gordon
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States.,Department of Nephrology, Stony Brook University, Stony Brook, NY, United States
| | - Lisa M Ballou
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States
| | - Richard Z Lin
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States.,Medical Service, Northport VA Medical Center, Northport, NY, United States
| | - Ira S Cohen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States
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9
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Liu Y, Xu X, Gao J, Naffaa MM, Liang H, Shi J, Wang HZ, Yang ND, Hou P, Zhao W, White KM, Kong W, Dou A, Cui A, Zhang G, Cohen IS, Zou X, Cui J. A PIP 2 substitute mediates voltage sensor-pore coupling in KCNQ activation. Commun Biol 2020; 3:385. [PMID: 32678288 PMCID: PMC7367283 DOI: 10.1038/s42003-020-1104-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/22/2020] [Indexed: 12/25/2022] Open
Abstract
KCNQ family K+ channels (KCNQ1-5) in the heart, nerve, epithelium and ear require phosphatidylinositol 4,5-bisphosphate (PIP2) for voltage dependent activation. While membrane lipids are known to regulate voltage sensor domain (VSD) activation and pore opening in voltage dependent gating, PIP2 was found to interact with KCNQ1 and mediate VSD-pore coupling. Here, we show that a compound CP1, identified in silico based on the structures of both KCNQ1 and PIP2, can substitute for PIP2 to mediate VSD-pore coupling. Both PIP2 and CP1 interact with residues amongst a cluster of amino acids critical for VSD-pore coupling. CP1 alters KCNQ channel function due to different interactions with KCNQ compared with PIP2. We also found that CP1 returned drug-induced action potential prolongation in ventricular myocytes to normal durations. These results reveal the structural basis of PIP2 regulation of KCNQ channels and indicate a potential approach for the development of anti-arrhythmic therapy.
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Affiliation(s)
- Yongfeng Liu
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Xianjin Xu
- grid.134936.a0000 0001 2162 3504Dalton Cardiovascular Research Center, Department of Physics and Astronomy, Department of Biochemistry, Institute for Data Science & Informatics, University of Missouri, Columbia, MO 65211 USA
| | - Junyuan Gao
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, and Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Moawiah M. Naffaa
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Hongwu Liang
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Jingyi Shi
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Hong Zhan Wang
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, and Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Nien-Du Yang
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Panpan Hou
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Wenshan Zhao
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Kelli McFarland White
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Wenjuan Kong
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Alex Dou
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Amy Cui
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Guohui Zhang
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Ira S. Cohen
- grid.36425.360000 0001 2216 9681Department of Physiology and Biophysics, and Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Xiaoqin Zou
- grid.134936.a0000 0001 2162 3504Dalton Cardiovascular Research Center, Department of Physics and Astronomy, Department of Biochemistry, Institute for Data Science & Informatics, University of Missouri, Columbia, MO 65211 USA
| | - Jianmin Cui
- grid.4367.60000 0001 2355 7002Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University in Saint Louis, Saint Louis, MO 63130 USA
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10
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Valiunas V, Cohen IS, Brink PR, Clausen C. A study of the outward background current conductance g K1, the pacemaker current conductance g f, and the gap junction conductance g j as determinants of biological pacing in single cells and in a two-cell syncytium using the dynamic clamp. Pflugers Arch 2020; 472:561-570. [PMID: 32415460 DOI: 10.1007/s00424-020-02378-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/21/2022]
Abstract
We previously demonstrated that a two-cell syncytium, composed of a ventricular myocyte and an mHCN2 expressing cell, recapitulated most properties of in vivo biological pacing induced by mHCN2-transfected hMSCs in the canine ventricle. Here, we use the two-cell syncytium, employing dynamic clamp, to study the roles of gf (pacemaker conductance), gK1 (background K+ conductance), and gj (intercellular coupling conductance) in biological pacing. We studied gf and gK1 in single HEK293 cells expressing cardiac sodium current channel Nav1.5 (SCN5A). At fixed gf, increasing gK1 hyperpolarized the cell and initiated pacing. As gK1 increased, rate increased, then decreased, finally ceasing at membrane potentials near EK. At fixed gK1, increasing gf depolarized the cell and initiated pacing. With increasing gf, rate increased reaching a plateau, then decreased, ceasing at a depolarized membrane potential. We studied gj via virtual coupling with two non-adjacent cells, a driver (HEK293 cell) in which gK1 and gf were injected without SCN5A and a follower (HEK293 cell), expressing SCN5A. At the chosen values of gK1 and gf oscillations initiated in the driver, when gj was increased synchronized pacing began, which then decreased by about 35% as gj approached 20 nS. Virtual uncoupling yielded similar insights into gj. We also studied subthreshold oscillations in physically and virtually coupled cells. When coupling was insufficient to induce pacing, passive spread of the oscillations occurred in the follower. These results show a non-monotonic relationship between gK1, gf, gj, and pacing. Further, oscillations can be generated by gK1 and gf in the absence of SCN5A.
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Affiliation(s)
- Virginijus Valiunas
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, 11794-8661, USA.
| | - Ira S Cohen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, 11794-8661, USA
| | - Peter R Brink
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, 11794-8661, USA
| | - Chris Clausen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, 11794-8661, USA
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11
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Lin RZ, Lu Z, Anyukhovsky EP, Jiang YP, Wang HZ, Gao J, Rosen MR, Ballou LM, Cohen IS. Regulation of heart rate and the pacemaker current by phosphoinositide 3-kinase signaling. J Gen Physiol 2019; 151:1051-1058. [PMID: 31217223 PMCID: PMC6683667 DOI: 10.1085/jgp.201812293] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 05/01/2019] [Accepted: 06/03/2019] [Indexed: 12/28/2022] Open
Abstract
Heart rate is set by the specialized tissue of the sinoatrial node. Lin et al. demonstrate a novel role for phosphoinositide 3-kinase in regulating cardiac pacemaking currents independently of the autonomic nervous system, a finding with relevance for diabetes, heart disease, and cancer. Heart rate in physiological conditions is set by the sinoatrial node (SN), the primary cardiac pacing tissue. Phosphoinositide 3-kinase (PI3K) signaling is a major regulatory pathway in all normal cells, and its dysregulation is prominent in diabetes, cancer, and heart failure. Here, we show that inhibition of PI3K slows the pacing rate of the SN in situ and in vitro and reduces the early slope of diastolic depolarization. Furthermore, inhibition of PI3K causes a negative shift in the voltage dependence of activation of the pacemaker current, IF, while addition of its second messenger, phosphatidylinositol 3,4,5-trisphosphate, induces a positive shift. These shifts in the activation of IF are independent of, and larger than, those induced by the autonomic nervous system. These results suggest that PI3K is an important regulator of heart rate, and perturbations in this signaling pathway may contribute to the development of arrhythmias.
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Affiliation(s)
- Richard Z Lin
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY.,Medical Service, Northport VA Medical Center, Northport, NY
| | - Zhongju Lu
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY.,Department of Medicine, Stony Brook University, Stony Brook, NY
| | - Evgeny P Anyukhovsky
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY
| | - Ya-Ping Jiang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY
| | - Hong Zhan Wang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY
| | - Junyuan Gao
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY
| | - Michael R Rosen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY.,Departments of Pharmacology and Pediatrics, Columbia University, New York, NY
| | - Lisa M Ballou
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY
| | - Ira S Cohen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY
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12
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Dave JK, Kulkarni SV, Pangaonkar PP, Stanczak M, McDonald ME, Cohen IS, Mehrotra P, Savage MP, Walinsky P, Ruggiero NJ, Fischman DL, Ogilby D, VanWhy C, Lombardi M, Forsberg F. Non-Invasive Intra-cardiac Pressure Measurements Using Subharmonic-Aided Pressure Estimation: Proof of Concept in Humans. Ultrasound Med Biol 2017; 43:2718-2724. [PMID: 28807449 PMCID: PMC5605408 DOI: 10.1016/j.ultrasmedbio.2017.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/05/2017] [Accepted: 07/11/2017] [Indexed: 05/04/2023]
Abstract
This study evaluated the feasibility of employing non-invasive intra-cardiac pressure estimation using subharmonic signals from ultrasound contrast agents in humans. This institutional review board-approved proof-of-concept study included 15 consenting patients scheduled for left and right heart catheterization. During the catheterization procedure, Definity was infused intra-venously at 4-10 mL/min. Ultrasound scanning was performed with a Sonix RP using pulse inversion, three incident acoustic output levels and 2.5-MHz transmit frequency. Radiofrequency data were processed and subharmonic amplitudes were compared with the pressure catheter data. The correlation coefficient between subharmonic signals and pressure catheter data ranged from -0.3 to -0.9. For acquisitions with optimum acoustic output, pressure errors between the subharmonic technique and catheter were as low as 2.6 mmHg. However, automatically determining optimum acoustic output during scanning for each patient remains to be addressed before clinical applicability can be decided.
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Affiliation(s)
- Jaydev K Dave
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
| | - Sushmita V Kulkarni
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; College of Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Purva P Pangaonkar
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Maria Stanczak
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Maureen E McDonald
- Department of Radiologic Sciences, Jefferson College of Health Professions, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ira S Cohen
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Praveen Mehrotra
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael P Savage
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul Walinsky
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nicholas J Ruggiero
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David L Fischman
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David Ogilby
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Carolyn VanWhy
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Matthew Lombardi
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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13
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Chauveau S, Anyukhovsky EP, Ben-Ari M, Naor S, Jiang YP, Danilo P, Rahim T, Burke S, Qiu X, Potapova IA, Doronin SV, Brink PR, Binah O, Cohen IS, Rosen MR. Induced Pluripotent Stem Cell-Derived Cardiomyocytes Provide In Vivo Biological Pacemaker Function. Circ Arrhythm Electrophysiol 2017; 10:e004508. [PMID: 28500172 PMCID: PMC5434966 DOI: 10.1161/circep.116.004508] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 04/06/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Although multiple approaches have been used to create biological pacemakers in animal models, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have not been investigated for this purpose. We now report pacemaker function of iPSC-CMs in a canine model. METHODS AND RESULTS Embryoid bodies were derived from human keratinocytes, their action potential characteristics determined, and their gene expression profiles and markers of differentiation identified. Atrioventricular blocked dogs were immunosuppressed, instrumented with VVI pacemakers, and injected subepicardially into the anterobasal left ventricle with 40 to 75 rhythmically contracting embryoid bodies (totaling 1.3-2×106 cells). ECG and 24-hour Holter monitoring were performed biweekly. After 4 to 13 weeks, epinephrine (1 μg kg-1 min-1) was infused, and the heart removed for histological or electrophysiological study. iPSC-CMs largely lost the markers of pluripotency, became positive for cardiac-specific markers. and manifested If-dependent automaticity. Epicardial pacing of the injection site identified matching beats arising from that site by week 1 after implantation. By week 4, 20% of beats were electronically paced, 60% to 80% of beats were matching, and mean and maximal biological pacemaker rates were 45 and 75 beats per minute. Maximum night and day rates of matching beats were 53±6.9 and 69±10.4 beats per minute, respectively, at 4 weeks. Epinephrine increased rate of matching beats from 35±4.3 to 65±4.0 beats per minute. Incubation of embryoid bodies with the vital dye, Dil, revealed the persistence of injected cells at the site of administration. CONCLUSIONS iPSC-CMs can integrate into host myocardium and create a biological pacemaker. Although this is a promising development, rate and rhythm of the iPSC-CMs pacemakers remain to be optimized.
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Affiliation(s)
| | | | | | - Shulamit Naor
- For the author affiliations, please see the Appendix
| | - Ya-Ping Jiang
- For the author affiliations, please see the Appendix
| | - Peter Danilo
- For the author affiliations, please see the Appendix
| | - Tania Rahim
- For the author affiliations, please see the Appendix
| | | | - Xiaoliang Qiu
- For the author affiliations, please see the Appendix
| | | | | | - Peter R Brink
- For the author affiliations, please see the Appendix
| | - Ofer Binah
- For the author affiliations, please see the Appendix
| | - Ira S Cohen
- For the author affiliations, please see the Appendix.
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14
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Cohen IS, Lin RZ, Ballou LM. Acquired long QT syndrome and phosphoinositide 3-kinase. Trends Cardiovasc Med 2017; 27:451-459. [PMID: 28687226 DOI: 10.1016/j.tcm.2017.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 01/08/2023]
Abstract
While it is well known that mutation of several different ion channels can cause congenital long QT syndrome, block of IKr is widely thought to be responsible for most cases of drug-induced acquired long QT syndrome (aLQTS). In this article, we review evidence supporting another cause of aLQTS due to inhibition of phosphoinositide 3-kinase (PI3K) signaling. Inhibition of PI3K affects multiple plateau currents, reducing IKr, IKs, and ICaL while increasing the persistent sodium current (INaP). The effects of PI3K inhibitors develop slowly, requiring hours to days to reach steady state. Dofetilide and terfenadine, an antihistamine on which much of the original IKr hypothesis was based, are among the many drugs that inhibit the PI3K pathway. Reduced PI3K signaling may also play a role in aLQTS associated with diabetes. Drug safety testing to identify aLQTS risk may be improved by examining PI3K-dependent effects that develop over time.
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Affiliation(s)
- Ira S Cohen
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY.
| | - Richard Z Lin
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY; Medical Service, Northport VA Medical Center, Northport, NY
| | - Lisa M Ballou
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY
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15
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Naffaa MM, Xu X, Liang H, Zhang G, Zhan Wang H, Goa J, Cohen IS, Zou X, Cui J. CP1 Opens I Ks Channels by Substituting PIP 2. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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16
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Cohen IS, Mathias RT. The renin-angiotensin system regulates transmural electrical remodeling in response to mechanical load. Prog Biophys Mol Biol 2016; 122:187-201. [PMID: 27645328 PMCID: PMC5161618 DOI: 10.1016/j.pbiomolbio.2016.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/13/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Ira S Cohen
- Department of Physiology & Biophysics, Institute for Molecular Cardiology, Stony Brook University, United States.
| | - Richard T Mathias
- Department of Physiology & Biophysics, Institute for Molecular Cardiology, Stony Brook University, United States
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17
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18
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Qiu XS, Chauveau S, Anyukhovsky EP, Rahim T, Jiang YP, Harleton E, Feinmark SJ, Lin RZ, Coronel R, Janse MJ, Opthof T, Rosen TS, Cohen IS, Rosen MR. Increased Late Sodium Current Contributes to the Electrophysiological Effects of Chronic, but Not Acute, Dofetilide Administration. Circ Arrhythm Electrophysiol 2016; 9:e003655. [PMID: 27071826 DOI: 10.1161/circep.115.003655] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 03/01/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Drugs are screened for delayed rectifier potassium current (IKr) blockade to predict long QT syndrome prolongation and arrhythmogenesis. However, single-cell studies have shown that chronic (hours) exposure to some IKr blockers (eg, dofetilide) prolongs repolarization additionally by increasing late sodium current (INa-L) via inhibition of phosphoinositide 3-kinase. We hypothesized that chronic dofetilide administration to intact dogs prolongs repolarization by blocking IKr and increasing INa-L. METHODS AND RESULTS We continuously infused dofetilide (6-9 μg/kg bolus+6-9 μg/kg per hour IV infusion) into anesthetized dogs for 7 hours, maintaining plasma levels within the therapeutic range. In separate experiments, myocardial biopsies were taken before and during 6-hour intravenous dofetide infusion, and the level of phospho-Akt was determined. Acute and chronic dofetilide effects on action potential duration (APD) were studied in canine left ventricular subendocardial slabs using microelectrode techniques. Dofetilide monotonically increased QTc and APD throughout 6.5-hour exposure. Dofetilide infusion during ≥210 minutes inhibited Akt phosphorylation. INa-L block with lidocaine shortened QTc and APD more at 6.5 hours than at 50 minutes (QTc) or 30 minutes (APD) dofetilide administration. In comparison, moxifloxacin, an IKr blocker with no effects on phosphoinositide 3-kinase and INa-L prolonged APD acutely but no additional prolongation occurred on chronic superfusion. Lidocaine shortened APD equally during acute and chronic moxifloxacin superfusion. CONCLUSIONS Increased INa-L contributes to chronic dofetilide effects in vivo. These data emphasize the need to include time and INa-L in evaluating the phosphoinositide 3-kinase inhibition-derived proarrhythmic potential of drugs and provide a mechanism for benefit from lidocaine administration in clinical acquired long QT syndrome.
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Affiliation(s)
- Xiaoliang S Qiu
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Samuel Chauveau
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Evgeny P Anyukhovsky
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Tania Rahim
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Ya-Ping Jiang
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Erin Harleton
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Steven J Feinmark
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Richard Z Lin
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Ruben Coronel
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Michiel J Janse
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Tobias Opthof
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Tove S Rosen
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Ira S Cohen
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.).
| | - Michael R Rosen
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
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19
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Kim J, Gao J, Cohen IS, Mathias RT. Angiotensin II Type 1 Receptor-Mediated Electrical Remodeling in Mouse Cardiac Myocytes. PLoS One 2015; 10:e0138711. [PMID: 26430746 PMCID: PMC4591968 DOI: 10.1371/journal.pone.0138711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 09/02/2015] [Indexed: 01/14/2023] Open
Abstract
We recently characterized an autocrine renin angiotensin system (RAS) in canine heart. Activation of Angiotensin II Type 1 Receptors (AT1Rs) induced electrical remodeling, including inhibition of the transient outward potassium current Ito, prolongation of the action potential (AP), increased calcium entry and increased contractility. Electrical properties of the mouse heart are very different from those of dog heart, but if a similar system existed in mouse, it could be uniquely studied through genetic manipulations. To investigate the presence of a RAS in mouse, we measured APs and Ito in isolated myocytes. Application of angiotensin II (A2) for 2 or more hours reduced Ito magnitude, without affecting voltage dependence, and prolonged APs in a dose-dependent manner. Based on dose-inhibition curves, the fast and slow components of Ito (Ito,fast and IK,slow) appeared to be coherently regulated by [A2], with 50% inhibition at an A2 concentration of about 400 nM. This very high K0.5 is inconsistent with systemic A2 effects, but is consistent with an autocrine RAS in mouse heart. Pre-application of the microtubule destabilizing agent colchicine eliminated A2 effects on Ito and AP duration, suggesting these effects depend on intracellular trafficking. Application of the biased agonist SII ([Sar1-Ile4-Ile8]A2), which stimulates receptor internalization without G protein activation, caused Ito reduction and AP prolongation similar to A2-induced changes. These data demonstrate AT1R mediated regulation of Ito in mouse heart. Moreover, all measured properties parallel those measured in dog heart, suggesting an autocrine RAS may be a fundamental feedback system that is present across species.
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Affiliation(s)
- Jeremy Kim
- Department of Physiology & Biophysics, State University of New York at Stony Brook, Stony Brook, New York, United States of America
| | - Junyuan Gao
- Department of Physiology & Biophysics, State University of New York at Stony Brook, Stony Brook, New York, United States of America
| | - Ira S. Cohen
- Department of Physiology & Biophysics, State University of New York at Stony Brook, Stony Brook, New York, United States of America
| | - Richard T. Mathias
- Department of Physiology & Biophysics, State University of New York at Stony Brook, Stony Brook, New York, United States of America
- * E-mail:
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20
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Abstract
Upregulation of phosphoinositide 3-kinase (PI3K) signaling is a common alteration in human cancer, and numerous drugs that target this pathway have been developed for cancer treatment. However, recent studies have implicated inhibition of the PI3K signaling pathway as the cause of a drug-induced long-QT syndrome in which alterations in several ion currents contribute to arrhythmogenic drug activity. Surprisingly, some drugs that were thought to induce long-QT syndrome by direct block of the rapid delayed rectifier (IKr) also seem to inhibit PI3K signaling, an effect that may contribute to their arrhythmogenicity. The importance of PI3K in regulating cardiac repolarization is underscored by evidence that QT interval prolongation in diabetes mellitus also may result from changes in multiple currents because of decreased insulin activation of PI3K in the heart. How PI3K signaling regulates ion channels to control the cardiac action potential is poorly understood. Hence, this review summarizes what is known about the effect of PI3K and its downstream effectors, including Akt, on sodium, potassium, and calcium currents in cardiac myocytes. We also refer to some studies in noncardiac cells that provide insight into potential mechanisms of ion channel regulation by this signaling pathway in the heart. Drug development and safety could be improved with a better understanding of the mechanisms by which PI3K regulates cardiac ion channels and the extent to which PI3K inhibition contributes to arrhythmogenic susceptibility.
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Affiliation(s)
- Lisa M Ballou
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.)
| | - Richard Z Lin
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.).
| | - Ira S Cohen
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.).
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21
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Wang HZ, Rosati B, Gordon C, Valiunas V, McKinnon D, Cohen IS, Brink PR. Inhibition of histone deacetylase (HDAC) by 4-phenylbutyrate results in increased junctional conductance between rat corpora smooth muscle cells. Front Pharmacol 2015; 6:9. [PMID: 25691868 PMCID: PMC4315027 DOI: 10.3389/fphar.2015.00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 01/11/2015] [Indexed: 01/02/2023] Open
Abstract
4-phenylbutyrate (4-PB) has been shown to increase the protein content in a number of cells types. One such protein is Connexin43 (Cx43). We show here that 4-phenylbutyrate exposure results in significantly elevated cell to cell coupling, as determined by dual whole cell patch clamp. Incubation with 5 mM 4PB for 24 h or more nearly doubles junctional conductance. Interestingly, mRNA levels for Cx43 declined with exposure to 4-PB while western blot analysis revealed not significant change in protein levels. These data are most consistent with stabilization of the existing Cx43 pool or alterations in the number of functional channels within an existing pool of active and silent channels. These data represent a baseline for testing the efficacy of increased connexin mediated coupling in a variety of multicellular functions including erectile function.
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Affiliation(s)
- Hong Zhan Wang
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA
| | - Barbara Rosati
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA ; Department of Physiology and Biophysics, Molecular Cardiology Institute, Stony Brook University Stony Brook, NY, USA
| | - Chris Gordon
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA
| | - Virginijus Valiunas
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA ; Department of Physiology and Biophysics, Molecular Cardiology Institute, Stony Brook University Stony Brook, NY, USA
| | - David McKinnon
- Department of Physiology and Biophysics, Molecular Cardiology Institute, Stony Brook University Stony Brook, NY, USA ; Department of Neurobiology and Behavior, Stony Brook University Stony Brook, NY, USA
| | - Ira S Cohen
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA ; Department of Physiology and Biophysics, Molecular Cardiology Institute, Stony Brook University Stony Brook, NY, USA
| | - Peter R Brink
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA ; Department of Physiology and Biophysics, Molecular Cardiology Institute, Stony Brook University Stony Brook, NY, USA
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22
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Abstract
Cellular delivery of small interfering RNAs to target cells of a tissue has the potential to travel by two intercellular pathways. For intimately apposed cells gap junctions allow transport exclusive of the extracellular space. For cells not in intimate contact, exocytotic release of vesicular contents and subsequent retrieval via endocytosis of exosomes and other vesicular contents represent an alternative intercellular delivery system that utilizes the extracellular space. Previous studies have shown siRNA/miRNA transfer from a delivery cell to a target cell via gap junction channels. We hypothesized that siRNA can be delivered via gap junctions and downregulate the expression of a reporter gene, the cyclic nucleotide-gated cation channel gene (mHCN2), in the recipient cells of cell pairs. Whole-cell patch clamp was used to measure the mHCN2-induced current and junctional conductance. The target cells were HEK293 cells that endogenously express Cx43 or HeLaCx43 cells, both transfected with mHCN2. The source cells were HEK293 or HeLaCx43 cells transfected with fluorescent-labeled siRNA targeting mHCN2. We found that siRNA targeting mHCN2 resulted in significant downregulation of mHCN2 currents both in single cells and the recipient cell of a cell pair. In addition we also documented downregulation in target cells that were not in contact with source cells suggesting an extracellular-mediated delivery. To test further for extracellular delivery HEK293/HCN2 or HeLaCx43/HCN2 cells were cultured in medium collected from HEK293 or HeLaCx43 cells transfected with fluorescent-labeled siRNA or fluorescent-labeled morpholino designed to target HCN2. After 24 h single HEK293/HCN2 or HeLaCx43cells showed accumulation of siRNA. The mHCN2 currents were also down regulated in cells with siRNA uptake. Application of 200 nmol/L Bafilomycin A1, which has been shown to affect endosome acidification and endocytotic activity, resulted in a smaller accumulation of fluorescent-labeled siRNA in single target cells. In distinction to siRNA, morpholinos targeting HCN2 exhibited greatly reduced extracellularly mediated transfer while in cell pairs, target cells exhibited reduced HCN2 currents consistent with effective gap junction-mediated delivery.
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Affiliation(s)
- Virginijus Valiunas
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Hong-Zhang Wang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Ling Li
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Chris Gordon
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Laima Valiuniene
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Ira S Cohen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Peter R Brink
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
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Chauveau S, Brink PR, Cohen IS. Stem cell-based biological pacemakers from proof of principle to therapy: a review. Cytotherapy 2014; 16:873-80. [PMID: 24831844 DOI: 10.1016/j.jcyt.2014.02.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 02/11/2014] [Accepted: 02/23/2014] [Indexed: 12/12/2022]
Abstract
Electronic pacemakers are the standard therapy for bradycardia-related symptoms but have shortcomings. Over the past 15 years, experimental evidence has demonstrated that gene and cell-based therapies can create a biological pacemaker. Recently, physiologically acceptable rates have been reported with an adenovirus-based approach. However, adenovirus-based protein expression does not last more than 4 weeks, which limits its clinical applicability. Cell-based platforms are potential candidates for longer expression. Currently there are two cell-based approaches being tested: (i) mesenchymal stem cells used as a suitcase for delivering pacemaker genes and (ii) pluripotent stem cells differentiated down a cardiac lineage with endogenous pacemaker activity. This review examines the current achievements in engineering a biological pacemaker, defines the patient population for whom this device would be useful and identifies the challenges still ahead before cell therapy can replace current electronic devices.
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Affiliation(s)
- Samuel Chauveau
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
| | - Peter R Brink
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
| | - Ira S Cohen
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA.
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Lu Z, Jiang YP, Wu CYC, Ballou LM, Liu S, Carpenter ES, Rosen MR, Cohen IS, Lin RZ. Increased persistent sodium current due to decreased PI3K signaling contributes to QT prolongation in the diabetic heart. Diabetes 2013; 62:4257-65. [PMID: 23974924 PMCID: PMC3837031 DOI: 10.2337/db13-0420] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diabetes is an independent risk factor for sudden cardiac death and ventricular arrhythmia complications of acute coronary syndrome. Prolongation of the QT interval on the electrocardiogram is also a risk factor for arrhythmias and sudden death, and the increased prevalence of QT prolongation is an independent risk factor for cardiovascular death in diabetic patients. The pathophysiological mechanisms responsible for this lethal complication are poorly understood. Diabetes is associated with a reduction in phosphoinositide 3-kinase (PI3K) signaling, which regulates the action potential duration (APD) of individual myocytes and thus the QT interval by altering multiple ion currents, including the persistent sodium current INaP. Here, we report a mechanism for diabetes-induced QT prolongation that involves an increase in INaP caused by defective PI3K signaling. Cardiac myocytes of mice with type 1 or type 2 diabetes exhibited an increase in APD that was reversed by expression of constitutively active PI3K or intracellular infusion of phosphatidylinositol 3,4,5-trisphosphate (PIP3), the second messenger produced by PI3K. The diabetic myocytes also showed an increase in INaP that was reversed by activated PI3K or PIP3. The increases in APD and INaP in myocytes translated into QT interval prolongation for both types of diabetic mice. The long QT interval of type 1 diabetic hearts was shortened by insulin treatment ex vivo, and this effect was blocked by a PI3K inhibitor. Treatment of both types of diabetic mouse hearts with an INaP blocker also shortened the QT interval. These results indicate that downregulation of cardiac PI3K signaling in diabetes prolongs the QT interval at least in part by causing an increase in INaP. This mechanism may explain why the diabetic population has an increased risk of life-threatening arrhythmias.
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Affiliation(s)
- Zhongju Lu
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
| | - Ya-Ping Jiang
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
| | - Chia-Yen C. Wu
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
| | - Lisa M. Ballou
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
| | - Shengnan Liu
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
| | - Eileen S. Carpenter
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Michael R. Rosen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
- Department of Pharmacology, Columbia University, New York, New York
| | - Ira S. Cohen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
- Corresponding author: Ira S. Cohen, , or Richard Z. Lin,
| | - Richard Z. Lin
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York
- Medical Service, Northport VA Medical Center, Northport, New York
- Corresponding author: Ira S. Cohen, , or Richard Z. Lin,
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Williams JC, Xu J, Lu Z, Klimas A, Chen X, Ambrosi CM, Cohen IS, Entcheva E. Computational optogenetics: empirically-derived voltage- and light-sensitive channelrhodopsin-2 model. PLoS Comput Biol 2013; 9:e1003220. [PMID: 24068903 PMCID: PMC3772068 DOI: 10.1371/journal.pcbi.1003220] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 07/28/2013] [Indexed: 11/18/2022] Open
Abstract
Channelrhodospin-2 (ChR2), a light-sensitive ion channel, and its variants have emerged as new excitatory optogenetic tools not only in neuroscience, but also in other areas, including cardiac electrophysiology. An accurate quantitative model of ChR2 is necessary for in silico prediction of the response to optical stimulation in realistic tissue/organ settings. Such a model can guide the rational design of new ion channel functionality tailored to different cell types/tissues. Focusing on one of the most widely used ChR2 mutants (H134R) with enhanced current, we collected a comprehensive experimental data set of the response of this ion channel to different irradiances and voltages, and used these data to develop a model of ChR2 with empirically-derived voltage- and irradiance- dependence, where parameters were fine-tuned via simulated annealing optimization. This ChR2 model offers: 1) accurate inward rectification in the current-voltage response across irradiances; 2) empirically-derived voltage- and light-dependent kinetics (activation, deactivation and recovery from inactivation); and 3) accurate amplitude and morphology of the response across voltage and irradiance settings. Temperature-scaling factors (Q10) were derived and model kinetics was adjusted to physiological temperatures. Using optical action potential clamp, we experimentally validated model-predicted ChR2 behavior in guinea pig ventricular myocytes. The model was then incorporated in a variety of cardiac myocytes, including human ventricular, atrial and Purkinje cell models. We demonstrate the ability of ChR2 to trigger action potentials in human cardiomyocytes at relatively low light levels, as well as the differential response of these cells to light, with the Purkinje cells being most easily excitable and ventricular cells requiring the highest irradiance at all pulse durations. This new experimentally-validated ChR2 model will facilitate virtual experimentation in neural and cardiac optogenetics at the cell and organ level and provide guidance for the development of in vivo tools. Optogenetics, the use of light-sensitive ion channels for stimulation of mammalian cells and tissues, offers specificity and superior precision of control compared to traditional chemical or electrical means of stimulation. In particular, Channelrhodospin-2 (ChR2), a light-sensitive ion channel, originally derived from algae, has found wide-spread application in neuroscience for controlled stimulation of different brain regions. More recently, this work was extended to other organs, including the heart, where it opens the possibility for a new generation of optical pacemakers. The development of new optogenetic tools that allow for more efficient optical stimulation can be guided by computational prediction of the response of different cells and tissues to light. In this report, we provide a new computational model of ChR2 that was empirically validated and can be inserted into different cell types – neurons or heart cells – for virtual optical stimulation and prediction of optimal light-delivery arrangements, minimum energy needs etc. Overall, virtual optogenetics can accelerate the development of new optical stimulation tools for better understanding and control of brain and heart function.
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Affiliation(s)
- John C. Williams
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Jianjin Xu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Zhongju Lu
- Department of Physiology & Biophysics, Stony Brook University, Stony Brook, New York, United States of America
| | - Aleksandra Klimas
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Xuxin Chen
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Christina M. Ambrosi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Ira S. Cohen
- Department of Physiology & Biophysics, Stony Brook University, Stony Brook, New York, United States of America
- Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Emilia Entcheva
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
- Department of Physiology & Biophysics, Stony Brook University, Stony Brook, New York, United States of America
- Institute for Molecular Cardiology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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Kaufman J, Gordon C, Bergamaschi R, Wang HZ, Cohen IS, Valiunas V, Brink PR. The effects of the histone deacetylase inhibitor 4-phenylbutyrate on gap junction conductance and permeability. Front Pharmacol 2013; 4:111. [PMID: 24027526 PMCID: PMC3759747 DOI: 10.3389/fphar.2013.00111] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 08/14/2013] [Indexed: 11/20/2022] Open
Abstract
Longitudinal resistance is a key factor in determining cardiac action potential propagation. Action potential conduction velocity has been shown to be proportional to the square root of longitudinal resistance. A major determinant of longitudinal resistance in myocardium is the gap junction channel, comprised connexin proteins. Within the ventricular myocardium connexin43 (Cx43) is the dominantly expressed connexin. Reduced numbers of gap junction channels will result in an increase in longitudinal resistance creating the possibility of slowed conduction velocity while increased numbers of channels would potentially result in an increase in conduction velocity. We sought to determine if inhibition of histone deacetylase (HDAC) by 4-phenylbutyrate (4-PB), a known inhibitor of HDAC resulted in an increase in junctional conductance and permeability, which is not the result of changes in single channel unitary conductance. These experiments were performed using HEK-293 cells and HeLa cells stably transfected with Cx43. Following treatment with increasing concentrations of 4-PB up-regulation of Cx43 was observed via Western blot analysis. Junctional (gj) conductance and unitary single channel conductance were measured via whole-cell patch clamp. In addition intercellular transfer of lucifer yellow (LY) was determined by fluorescence microscopy. The data in this study indicate that 4-PB is able to enhance functional Cx43 gap junction coupling as indicated by LY dye transfer and multichannel and single channel data along with Western blot analysis. As a corollary, pharmacological agents such as 4-PB have the potential, by increasing intercellular coupling, to reduce the effect of ischemia. It remains to be seen whether drugs like 4-PB will be effective in preventing cardiac maladies.
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Affiliation(s)
- Joshua Kaufman
- Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA
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Boink GJJ, Duan L, Nearing BD, Shlapakova IN, Sosunov EA, Anyukhovsky EP, Bobkov E, Kryukova Y, Ozgen N, Danilo P, Cohen IS, Verrier RL, Robinson RB, Rosen MR. HCN2/SkM1 gene transfer into canine left bundle branch induces stable, autonomically responsive biological pacing at physiological heart rates. J Am Coll Cardiol 2013; 61:1192-201. [PMID: 23395072 DOI: 10.1016/j.jacc.2012.12.031] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Revised: 12/07/2012] [Accepted: 12/18/2012] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This study sought to test the hypothesis that hyperpolarization-activated cyclic nucleotide-gated (HCN)-based biological pacing might be improved significantly by hyperpolarizing the action potential (AP) threshold via coexpression of the skeletal muscle sodium channel 1 (SkM1). BACKGROUND Gene-based biological pacemakers display effective in vivo pacemaker function. However, approaches used to date have failed to manifest optimal pacemaker properties, defined as basal beating rates of 60 to 90 beats/min, a brisk autonomic response achieving maximal rates of 130 to 160 beats/min, and low to absent electronic backup pacing. METHODS We implanted adenoviral SkM1, HCN2, or HCN2/SkM1 constructs into left bundle branches (LBB) or left ventricular (LV) epicardium of atrioventricular-blocked dogs. RESULTS During stable peak gene expression on days 5 to 7, HCN2/SkM1 LBB-injected dogs showed highly stable in vivo pacemaker activity superior to SkM1 or HCN2 alone and superior to LV-implanted dogs with regard to beating rates (resting approximately 80 beats/min; maximum approximately 130 beats/min), no dependence on electronic backup pacing, and enhanced modulation of pacemaker function during circadian rhythm or epinephrine infusion. In vitro isolated LV of dogs overexpressing SkM1 manifested a significantly more negative AP threshold. CONCLUSIONS LBB-injected HCN2/SkM1 potentially provides a more clinically suitable biological pacemaker strategy than other reported constructs. This superiority is attributable to the more negative AP threshold and injection into the LBB.
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Affiliation(s)
- Gerard J J Boink
- Department of Pharmacology, Columbia University, New York, NY 10032, USA
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Clausen C, Valiunas V, Brink PR, Cohen IS. MATLAB implementation of a dynamic clamp with bandwidth of >125 kHz capable of generating I Na at 37 °C. Pflugers Arch 2012; 465:497-507. [PMID: 23224681 DOI: 10.1007/s00424-012-1186-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 11/02/2012] [Accepted: 11/12/2012] [Indexed: 10/27/2022]
Abstract
We describe the construction of a dynamic clamp with a bandwidth of >125 kHz that utilizes a high-performance, yet low-cost, standard home/office PC interfaced with a high-speed (16 bit) data acquisition module. High bandwidth is achieved by exploiting recently available software advances (code-generation technology and optimized real-time kernel). Dynamic-clamp programs are constructed using Simulink, a visual programming language. Blocks for computation of membrane currents are written in the high-level MATLAB language; no programming in C is required. The instrument can be used in single- or dual-cell configurations, with the capability to modify programs while experiments are in progress. We describe an algorithm for computing the fast transient Na(+) current (I Na) in real time and test its accuracy and stability using rate constants appropriate for 37 °C. We then construct a program capable of supplying three currents to a cell preparation: I Na, the hyperpolarizing-activated inward pacemaker current (I f) and an inward-rectifier K(+) current (I K1). The program corrects for the IR drop due to electrode current flow and also records all voltages and currents. We tested this program on dual patch-clamped HEK293 cells where the dynamic clamp controls a current-clamp amplifier and a voltage-clamp amplifier controls membrane potential, and current-clamped HEK293 cells where the dynamic clamp produces spontaneous pacing behavior exhibiting Na(+) spikes in otherwise passive cells.
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Affiliation(s)
- Chris Clausen
- Department of Physiology and Biophysics and Institute for Molecular Cardiology, Health Sciences Center, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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Affiliation(s)
- Sumeet K Chhabra
- Division of Cardiology, Department of Medicine, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
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Brink PR, Valiunas V, Gordon C, Rosen MR, Cohen IS. Can gap junctions deliver? Biochim Biophys Acta 2012; 1818:2076-81. [PMID: 21986484 DOI: 10.1016/j.bbamem.2011.09.025] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/09/2011] [Accepted: 09/23/2011] [Indexed: 01/08/2023]
Abstract
In vivo delivery of small interfering RNAs (siRNAs) to target cells via the extracellular space has been hampered by dilution effects and immune responses. Gap junction-mediated transfer between cells avoids the extracellular space and its associated limitations. Because of these advantages cell based delivery via gap junctions has emerged as a viable alternative for siRNA or miRNA delivery. Here we discuss the advantages and disadvantages of extracellular delivery and cell to cell delivery via gap junction channels composed of connexins. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Affiliation(s)
- Peter R Brink
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA.
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Özgen N, Lu Z, Boink GJJ, Lau DH, Shlapakova IN, Bobkov Y, Danilo P, Cohen IS, Rosen MR. Microtubules and angiotensin II receptors contribute to modulation of repolarization induced by ventricular pacing. Heart Rhythm 2012; 9:1865-72. [PMID: 22820054 DOI: 10.1016/j.hrthm.2012.07.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Left ventricular pacing (LVP) in canine heart alters ventricular activation, leading to reduced transient outward potassium current (I(to)), loss of the epicardial action potential notch, and T-wave vector displacement. These repolarization changes, referred to as cardiac memory, are initiated by locally increased angiotensin II (AngII) levels. In HEK293 cells in which Kv4.3 and KChIP2, the channel subunits contributing to I(to), are overexpressed with the AngII receptor 1 (AT1R), AngII induces a decrease in I(to) as the result of internalization of a Kv4.3/KChIP2/AT1R macromolecular complex. OBJECTIVE To test the hypothesis that in canine heart in situ, 2h LVP-induced decreases in membrane KChIP2, AT1R, and I(to) are prevented by blocking subunit trafficking. METHODS We used standard electrophysiological, biophysical, and biochemical methods to study 4 groups of dogs: (1) Sham, (2) 2h LVP, (3) LVP + colchicine (microtubule-disrupting agent), and (4) LVP + losartan (AT1R blocker). RESULTS The T-wave vector displacement was significantly greater in LVP than in Sham and was inhibited by colchicine or losartan. Epicardial biopsies showed significant decreases in KChIP2 and AT1R proteins in the membrane fraction after LVP but not after sham treatment, and these decreases were prevented by colchicine or losartan. Colchicine but not losartan significantly reduced microtubular polymerization. In isolated ventricular myocytes, AngII-induced I(to) reduction and loss of action potential notch were blocked by colchicine. CONCLUSIONS LVP-induced reduction of KChIP2 in plasma light membranes depends on an AngII-mediated pathway and intact microtubular status. Loss of I(to) and the action potential notch appear to derive from AngII-initiated trafficking of channel subunits.
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Affiliation(s)
- Nazira Özgen
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
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Boink GJJ, Nearing BD, Shlapakova IN, Duan L, Kryukova Y, Bobkov Y, Tan HL, Cohen IS, Danilo P, Robinson RB, Verrier RL, Rosen MR. Ca(2+)-stimulated adenylyl cyclase AC1 generates efficient biological pacing as single gene therapy and in combination with HCN2. Circulation 2012; 126:528-36. [PMID: 22753192 DOI: 10.1161/circulationaha.111.083584] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Biological pacing performed solely via HCN2 gene transfer in vivo results in relatively slow idioventricular rates and only moderate autonomic responsiveness. We induced biological pacing using the Ca(2+)-stimulated adenylyl cyclase AC1 gene expressed alone or in combination with HCN2 and compared outcomes with those with single-gene HCN2 transfer. METHODS AND RESULTS We implanted adenoviral HCN2, AC1, or HCN2/AC1 constructs into the left bundle branches of atrioventricular-blocked dogs. During steady-state gene expression (days 5-7), differences between AC1, HCN2/AC1, and HCN2 alone were evident in basal beating rate, escape time, and dependence on electronic backup pacing. In HCN2, AC1, and HCN2/AC1, these parameters were as follows: basal beating rate: 50±1.5, 60±5.0, and 129±28.9 bpm (P<0.05 for HCN2/AC1 versus HCN2 or AC1 alone), respectively; escape time: 2.4±0.2, 1.3±0.2, and 1.1±.0.4 seconds (P<0.05 for AC1 and HCN2/AC1 versus HCN2); and percent electronic beats: 34±8%, 2±1%, and 6±2% (P<0.05 for AC1 and HCN2/AC1 versus HCN2). Instantaneous (SD1) and long-term (SD2) heart rate variability and circadian rhythm analyzed via 24-hour Holter recordings showed a shift toward greater sensitivity to parasympathetic modulation in animals injected with AC1 and a high degree of sympathetic modulation in animals injected with HCN2/AC1. CONCLUSION AC1 or HCN2/AC1 overexpression in left bundle branches provides highly efficient biological pacing and greater sensitivity to autonomic modulation than HCN2 alone.
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Affiliation(s)
- Gerard J J Boink
- Department of Pharmacology, Center for Molecular Therapeutics, Columbia University, New York, NY 10032, USA
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Boink GJJ, Lu J, Driessen HE, Duan L, Sosunov EA, Anyukhovsky EP, Shlapakova IN, Lau DH, Rosen TS, Danilo P, Jia Z, Ozgen N, Bobkov Y, Guo Y, Brink PR, Kryukova Y, Robinson RB, Entcheva E, Cohen IS, Rosen MR. Effect of skeletal muscle Na(+) channel delivered via a cell platform on cardiac conduction and arrhythmia induction. Circ Arrhythm Electrophysiol 2012; 5:831-40. [PMID: 22722661 DOI: 10.1161/circep.111.969907] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND In depolarized myocardial infarct epicardial border zones, the cardiac sodium channel is largely inactivated, contributing to slow conduction and reentry. We have demonstrated that adenoviral delivery of the skeletal muscle Na(+) channel (SkM1) to epicardial border zones normalizes conduction and reduces induction of ventricular tachycardia/ventricular fibrillation. We now studied the impact of canine mesenchymal stem cells (cMSCs) in delivering SkM1. METHODS AND RESULTS cMSCs were isolated and transfected with SkM1. Coculture experiments showed cMSC/SkM1 but not cMSC alone and maintained fast conduction at depolarized potentials. We studied 3 groups in the canine 7d infarct: sham, cMSC, and cMSC/SkM1. In vivo epicardial border zones electrograms were broad and fragmented in sham, narrower in cMSCs, and narrow and unfragmented in cMSC/SkM1 (P<0.05). During programmed electrical stimulation of epicardial border zones, QRS duration in cMSC/SkM1 was shorter than in cMSC and sham (P<0.05). Programmed electrical stimulation-induced ventricular tachycardia/ventricular fibrillation was equivalent in all groups (P>0.05). CONCLUSION cMSCs provide efficient delivery of SkM1 current. The interventions performed (cMSCs or cMSC/SkM1) were neither antiarrhythmic nor proarrhythmic. Comparing outcomes with cMSC/SkM1 and viral gene delivery highlights the criticality of the delivery platform to SkM1 antiarrhythmic efficacy.
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Affiliation(s)
- Gerard J J Boink
- Department of Pharmacology, Center for Molecular Therapeutics, Columbia University, New York, NY 10032, USA
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Boink GJ, Lau DH, Shlapakova IN, Sosunov EA, Anyukhovsky EP, Driessen HE, Dun W, Chen M, Danilo P, Rosen TS, Őzgen N, Duffy HS, Kryukova Y, Boyden PA, Robinson RB, Brink PR, Cohen IS, Rosen MR. SkM1 and Cx32 improve conduction in canine myocardial infarcts yet only SkM1 is antiarrhythmic. Cardiovasc Res 2012; 94:450-9. [PMID: 22374989 PMCID: PMC3410408 DOI: 10.1093/cvr/cvs107] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 02/20/2012] [Accepted: 02/23/2012] [Indexed: 11/13/2022] Open
Abstract
AIMS Reentry accounts for most life-threatening arrhythmias, complicating myocardial infarction, and therapies that consistently prevent reentry from occurring are lacking. In this study, we compare antiarrhythmic effects of gene transfer of green fluorescent protein (GFP; sham), the skeletal muscle sodium channel (SkM1), the liver-specific connexin (Cx32), and SkM1/Cx32 in the subacute canine infarct. METHODS AND RESULTS Immediately after ligation of the left anterior descending artery, viral constructs were implanted in the epicardial border zone (EBZ). Five to 7 days later, efficient restoration of impulse propagation (narrow QRS and local electrogram duration) occurred in SkM1, Cx32, and SkM1/Cx32 groups (P< 0.05 vs. GFP). Programmed electrical stimulation from the EBZ induced sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) in 15/22 GFP dogs vs. 2/12 SkM1, 6/14 Cx32, and 8/10 SkM1/Cx32 (P< 0.05 SkM1 vs. GFP). GFP, SkM1, and SkM1/Cx32 had predominantly polymorphic VT/VF, whereas in Cx32 dogs, monomorphic VT predominated (P< 0.05 for Cx32 vs. GFP). Tetrazolium red staining showed significantly larger infarcts in Cx32- vs. GFP-treated animals (P< 0.05). CONCLUSION Whereas SkM1 gene transfer reduces the incidence of inducible VT/VF, Cx32 therapy to improve gap junctional conductance results in larger infarct size, a different VT morphology, and no antiarrhythmic efficacy.
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Affiliation(s)
- Gerard J.J. Boink
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Interuniversity Cardiology Institute of the Netherlands (ICIN), Utrecht, The Netherlands
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - David H. Lau
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Iryna N. Shlapakova
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Operating Room RN, Meadowlands Hospital Medical Center, 55 Meadowlands Parkway, Secaucus, NJ 07094, USA
| | - Eugene A. Sosunov
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Evgeny P. Anyukhovsky
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Helen E. Driessen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Graduate School of Life Sciences, Utrecht University, Utrecht, The Netherlands
| | - Wen Dun
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Ming Chen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Peter Danilo
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Tove S. Rosen
- Department of Pediatrics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Nazira Őzgen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Heather S. Duffy
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Beth Israel Deaconess Medical Center, Harvard Medical School, Center for Life Sciences, CLS 913, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Yelena Kryukova
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Penelope A Boyden
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Richard B. Robinson
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Peter R. Brink
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
| | - Ira S. Cohen
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
| | - Michael R. Rosen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Department of Pediatrics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
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Lu Z, Wu CYC, Jiang YP, Ballou LM, Clausen C, Cohen IS, Lin RZ. Suppression of phosphoinositide 3-kinase signaling and alteration of multiple ion currents in drug-induced long QT syndrome. Sci Transl Med 2012; 4:131ra50. [PMID: 22539774 PMCID: PMC3494282 DOI: 10.1126/scitranslmed.3003623] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many drugs, including some commonly used medications, can cause abnormal heart rhythms and sudden death, as manifest by a prolonged QT interval in the electrocardiogram. Cardiac arrhythmias caused by drug-induced long QT syndrome are thought to result mainly from reductions in the delayed rectifier potassium ion (K(+)) current I(Kr). Here, we report a mechanism for drug-induced QT prolongation that involves changes in multiple ion currents caused by a decrease in phosphoinositide 3-kinase (PI3K) signaling. Treatment of canine cardiac myocytes with inhibitors of tyrosine kinases or PI3Ks caused an increase in action potential duration that was reversed by intracellular infusion of phosphatidylinositol 3,4,5-trisphosphate. The inhibitors decreased the delayed rectifier K(+) currents I(Kr) and I(Ks), the L-type calcium ion (Ca(2+)) current I(Ca,L), and the peak sodium ion (Na(+)) current I(Na) and increased the persistent Na(+) current I(NaP). Computer modeling of the canine ventricular action potential showed that the drug-induced change in any one current accounted for less than 50% of the increase in action potential duration. Mouse hearts lacking the PI3K p110α catalytic subunit exhibited a prolonged action potential and QT interval that were at least partly a result of an increase in I(NaP). These results indicate that down-regulation of PI3K signaling directly or indirectly via tyrosine kinase inhibition prolongs the QT interval by affecting multiple ion channels. This mechanism may explain why some tyrosine kinase inhibitors in clinical use are associated with increased risk of life-threatening arrhythmias.
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Affiliation(s)
- Zhongju Lu
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Chia-Yen C. Wu
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ya-Ping Jiang
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Lisa M. Ballou
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Chris Clausen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ira S. Cohen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Richard Z. Lin
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY 11794, USA
- Northport Veterans Affairs Medical Center, Northport, NY 11768, USA
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Valiunas V, Clausen C, Butz R, Valiuniene L, Rosen MR, Brink PR, Cohen IS. The Dynamic Clamp Induced Pacing in Single and Coupled Cells. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Zhang H, Lau DH, Shlapakova IN, Zhao X, Danilo P, Robinson RB, Cohen IS, Qu D, Xu Z, Rosen MR. Implantation of Sinoatrial Node Cells into Canine Right Ventricle: Biological Pacing Appears Limited by the Substrate. Cell Transplant 2011. [DOI: 10.3727/096368911x565038b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Biological pacing has been proposed as a physiologic counterpart to electronic pacing, and the sinoatrial node (SAN) is the general standard for biological pacemakers. We tested the expression of SAN pacemaker cell activity when implanted autologously in the right ventricle (RV). We induced complete heart block and implanted electronic pacemakers in the RV of adult mongrel dogs. Autologous SAN cells isolated enzymatically were studied by patch clamp to confirm SAN identity. SAN cells (400,000) were injected into the RV subepicardial free wall and dogs were monitored for 2 weeks. Pacemaker function was assessed by overdrive pacing and IV epinephrine challenge. SAN cells expressed a time-dependent inward current (If) activating on hyperpolarization: density = 4.3 ± 0.6 pA/pF at −105 mV. Four of the six dogs demonstrated >50% of beats originating from the implant site at 24 h. Biological pacemaker rates on days 7–14 = 45–55 bpm and post-overdrive escape times = 1.5–2.5 s. Brisk catecholamine responsiveness occurred. Dogs implanted with autologous SAN cells manifest biological pacing properties dissimilar from those of the anatomic SAN. This highlights the importance of cell and substrate interaction in generating biological pacemaker function.
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Affiliation(s)
- Hao Zhang
- Changhai Hospital, Second Military Medical University, Shanghai, China
| | - David H. Lau
- Department of Pharmacology, Center for Molecular Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Iryna N. Shlapakova
- Department of Pharmacology, Center for Molecular Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Xin Zhao
- Division of Cardiology, First Affiliated Hospital of Soochow University, Su Zhou, China
| | - Peter Danilo
- Department of Pharmacology, Center for Molecular Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Richard B. Robinson
- Department of Pharmacology, Center for Molecular Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Ira S. Cohen
- Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Dan Qu
- Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhiyun Xu
- Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Michael R. Rosen
- Department of Pharmacology, Center for Molecular Therapeutics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Jia Z, Valiunas V, Lu Z, Bien H, Liu H, Wang HZ, Rosati B, Brink PR, Cohen IS, Entcheva E. Stimulating cardiac muscle by light: cardiac optogenetics by cell delivery. Circ Arrhythm Electrophysiol 2011; 4:753-60. [PMID: 21828312 DOI: 10.1161/circep.111.964247] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND After the recent cloning of light-sensitive ion channels and their expression in mammalian cells, a new field, optogenetics, emerged in neuroscience, allowing for precise perturbations of neural circuits by light. However, functionality of optogenetic tools has not been fully explored outside neuroscience, and a nonviral, nonembryogenesis-based strategy for optogenetics has not been shown before. METHODS AND RESULTS We demonstrate the utility of optogenetics to cardiac muscle by a tandem cell unit (TCU) strategy, in which nonexcitable cells carry exogenous light-sensitive ion channels, and, when electrically coupled to cardiomyocytes, produce optically excitable heart tissue. A stable channelrhodopsin2 (ChR2)-expressing cell line was developed, characterized, and used as a cell delivery system. The TCU strategy was validated in vitro in cell pairs with adult canine myocytes (for a wide range of coupling strengths) and in cardiac syncytium with neonatal rat cardiomyocytes. For the first time, we combined optical excitation and optical imaging to capture light-triggered muscle contractions and high-resolution propagation maps of light-triggered electric waves, found to be quantitatively indistinguishable from electrically triggered waves. CONCLUSIONS Our results demonstrate feasibility to control excitation and contraction in cardiac muscle by light, using the TCU approach. Optical pacing in this case uses less energy, offers superior spatiotemporal control and remote access and can serve not only as an elegant tool in arrhythmia research but may form the basis for a new generation of light-driven cardiac pacemakers and muscle actuators. The TCU strategy is extendable to (nonviral) stem cell therapy and is directly relevant to in vivo applications.
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Affiliation(s)
- Zhiheng Jia
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-8181, USA
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R. Rosen M, B. Robinson R, J. Janse M, Coronel R, R. Brink P, S. Cohen I. Antiarrhythmic Gene Therapy for Depressed Conduction in Myocardial Infarction. J Arrhythm 2011. [DOI: 10.4020/jhrs.27.ss5_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Anyukhovsky EP, Sosunov EA, Kryukova YN, Prestia K, Ozgen N, Rivaud M, Cohen IS, Robinson RB, Rosen MR. Expression of skeletal muscle sodium channel (Nav1.4) or connexin32 prevents reperfusion arrhythmias in murine heart. Cardiovasc Res 2011; 89:41-50. [PMID: 20823275 PMCID: PMC3002874 DOI: 10.1093/cvr/cvq284] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 08/17/2010] [Accepted: 08/30/2010] [Indexed: 12/22/2022] Open
Abstract
AIMS acute myocardial ischaemia induces a decrease in resting membrane potential [which leads to reduction of action potential (AP) V(max)] and intracellular acidification (which closes gap junctions). Both contribute to conduction slowing. We hypothesized that ventricular expression of the skeletal muscle Na(+) channel, Nav1.4 (which activates fully at low membrane potentials), or connexin32 (Cx32, which is less pH-sensitive than connexin43) would support conduction and be antiarrhythmic. We tested this hypothesis in a murine model of ischaemia and reperfusion arrhythmias. METHODS AND RESULTS empty adenovirus (Sham) or adenoviral constructs expressing either SkM1 (gene encoding Nav1.4) or Cx32 genes were injected into the left ventricular wall. Four days later, ventricular tachycardia (VT) occurred during reperfusion following a 5 min coronary occlusion. In Nav1.4- and Cx32-expressing mice, VT incidence and duration were lower than in Sham (P < 0.05). In vitro multisite microelectrode mapping was performed in the superfused right ventricular wall. To simulate ischaemic conditions, [K(+)] in solution was increased to 10 mmol/L and/or pH was decreased to 6.0. Western blots revealed Cx32 and Nav1.4 expression in both ventricles. Nav1.4 APs showed higher V(max) and conduction velocity (CV) than Shams at normal and elevated [K(+)]. Exposure of tissue to acid solution reduced intracellular pH to 6.4. There was no difference in CV between Sham and Cx32 groups in control solution. Acid solution slowed CV in Sham (P < 0.05) but not in Cx32. CONCLUSION Nav1.4 or Cx32 expression preserved normal conduction in murine hearts and decreased the incidence of reperfusion VT.
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MESH Headings
- Animals
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/physiopathology
- Arrhythmias, Cardiac/prevention & control
- Connexins/genetics
- Connexins/physiology
- Disease Models, Animal
- Electrocardiography
- Gene Expression
- Heart Conduction System/physiopathology
- Hydrogen-Ion Concentration
- In Vitro Techniques
- Male
- Membrane Potentials
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle Proteins/genetics
- Muscle Proteins/physiology
- Muscle, Skeletal/physiology
- Myocardial Reperfusion Injury/genetics
- Myocardial Reperfusion Injury/physiopathology
- Myocardial Reperfusion Injury/prevention & control
- Potassium/metabolism
- Rats
- Sodium Channels/genetics
- Sodium Channels/physiology
- Tachycardia, Ventricular/genetics
- Tachycardia, Ventricular/physiopathology
- Tachycardia, Ventricular/prevention & control
- Gap Junction beta-1 Protein
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Affiliation(s)
- Evgeny P Anyukhovsky
- Department of Pharmacology, Center for Molecular Therapeutics, College of Physicians and Surgeons of Columbia University, 630 West 168 Street, PH 7West-318, New York, NY 10032, USA.
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Potapova IA, Cohen IS, Doronin SV. Von willebrand factor increases endothelial cell adhesiveness for human mesenchymal stem cells by activating p38 mitogen-activated protein kinase. Stem Cell Res Ther 2010; 1:35. [PMID: 21083900 PMCID: PMC3025437 DOI: 10.1186/scrt35] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 11/17/2010] [Indexed: 12/17/2022] Open
Abstract
Introduction Delivered systemically or natively circulating mesenchymal stem cells accumulate in injured tissues. During homing mesenchymal stem cells adhere to endothelial cells and infiltrate underlying tissue. Previously we have shown that adhesiveness of endothelial cells for mesenchymal stem cells correlates with the inhibition of mitochondrial function of endothelial cells and secretion of von Willebrand factor. We hypothesized that von Willebrand factor is an auto/paracrine regulator of endothelial cell adhesiveness and studied the effect of von Willebrand factor on adhesion of mesenchymal stem cells to endothelial cells. Methods We used Affymetrix DNA microarrays, human protein phospho-MAPK array, Western blot, cell-based ELISA and flow cytometry analysis to study the activation of endothelial cells by von Willebrand factor. Cell adhesion assay and protein kinase inhibitors were used to evaluate the role of mitogen-activated protein kinases in the regulation of endothelial cell adhesiveness for mesenchymal stem cell. Results Treatment of endothelial cells with von Willebrand factor stimulated the mesenchymal stem cell adhesion in a time- and concentration-dependent manner. Mesenchymal stem cells did not adhere to immobilized von Willebrand factor and did not express receptors for von Willebrand factor suggesting that the stimulation of the mesenchymal stem cell adhesion is a result of endothelial cell activation with von Willebrand factor. Treatment of endothelial cells with von Willebrand factor activated ERK-1,2 and p38 MAPK without an effect on gene or cell surface expression of E-selectin, P-selectin, VCAM1 and ICAM1. Inhibition of p38 MAPK, but not ERK-1,2, in endothelial cells completely abrogated the stimulation of the mesenchymal stem cell adhesion by von Willebrand factor. Conclusions Von Willebrand factor is an auto/paracrine regulator of endothelial cells. Activation of p38 MAPK in endothelial cells by von Willebrand factor is responsible for the regulation of endothelial cell adhesiveness for mesenchymal stem cells.
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Affiliation(s)
- Irina A Potapova
- Department of Physiology and Biophysics, Stony Brook University, Nicolls Road, Stony Brook, NY 11794, USA.
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Shlapakova IN, Nearing BD, Lau DH, Boink GJJ, Danilo P, Kryukova Y, Robinson RB, Cohen IS, Rosen MR, Verrier RL. Biological pacemakers in canines exhibit positive chronotropic response to emotional arousal. Heart Rhythm 2010; 7:1835-40. [PMID: 20708103 DOI: 10.1016/j.hrthm.2010.08.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 08/06/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND Biological pacemakers based on the HCN2 channel isoform respond to beta-adrenergic and muscarinic stimulation, suggesting a capacity to respond to autonomic input. OBJECTIVE The purpose of this study was to investigate autonomic response to emotional arousal in canines implanted with murine HCN2-based biological pacemakers using gene therapy. METHODS An electronic pacemaker was implanted with its lead in the right ventricular apical endocardium (VVI 35 bpm). An adenoviral HCN2/GFP construct (Ad-HCN2, n = 7) or saline (control, n = 5) was injected into the left bundle branch on day 2 after radiofrequency ablation of the atrioventricular node to induce complete atrioventricular block. Emotional arousal was achieved by presenting food following an overnight fast. Autonomic control was evaluated with Poincaré plots of R-R(N) against R-R(N+1) intervals to characterize heart rate variability (HRV) and with continuous RR interval assessment via 24-hour ambulatory ECG. The 24-hour ECG and Poincaré plot shape were analyzed. RESULTS During day 1 after biological pacemaker implantation, Poincaré HRV parameters and RR intervals were unchanged with food presentation. However, on day 7, food presentation was accompanied by an increase in HRV (SD1, p < 0.07, and SD2, p < 0.05) and shortening of RR interval (P < .05) in dogs with Ad-HCN2 but not in controls. CONCLUSION This is the first demonstration that biological pacemakers are capable of responding to natural arousal stimuli to elicit appropriate chronotropic responses, a potential advantage over electronic pacemakers.
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Affiliation(s)
- Iryna N Shlapakova
- Columbia University College of Physicians and Surgeons, New York, New York, USA
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Brink PR, Robinson RB, Rosen MR, Cohen IS. In vivo cellular delivery of siRNA. IDrugs 2010; 13:383-387. [PMID: 20506060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Current in vivo approaches for the delivery of siRNAs have been hindered by inefficient targeting to cells and by the triggering of immune responses. The cellular delivery of siRNA by immunoprivileged cells avoids the immune response, because the siRNA is delivered from one cell interior to another via gap junctions, thereby avoiding the extracellular compartment. Human mesenchymal stem cells (hMSCs) can be delivered focally or systemically, and have also exhibited the ability to migrate to targeted tissue in vivo. These features suggest the potential use of hMSCs as a cellular delivery system for siRNA. This feature review discusses the role of gap junctions to facilitate the transfer of siRNA directly to target cells, thus avoiding the disadvantages involved with approaches that are dependent on the extracellular space for siRNA delivery.
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Affiliation(s)
- Peter R Brink
- Stony Brook University, Department of Physiology and Biophysics, Stony Brook, NY 11794, USA.
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Coronel R, Lau DH, Sosunov EA, Janse MJ, Danilo P, Anyukhovsky EP, Wilms-Schopman FJG, Opthof T, Shlapakova IN, Ozgen N, Prestia K, Kryukova Y, Cohen IS, Robinson RB, Rosen MR. Cardiac expression of skeletal muscle sodium channels increases longitudinal conduction velocity in the canine 1-week myocardial infarction. Heart Rhythm 2010; 7:1104-10. [PMID: 20385252 DOI: 10.1016/j.hrthm.2010.04.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 04/02/2010] [Indexed: 11/17/2022]
Abstract
BACKGROUND Skeletal muscle sodium channel (Nav1.4) expression in border zone myocardium increases action potential upstroke velocity in depolarized isolated tissue. Because resting membrane potential in the 1-week canine infarct is reduced, we hypothesized that conduction velocity (CV) is greater in Nav1.4 dogs compared with in control dogs. OBJECTIVE The purpose of this study was to measure CV in the infarct border zone border in dogs with and without Nav1.4 expression. METHODS Adenovirus was injected in the infarct border zone in 34 dogs. The adenovirus incorporated the Nav1.4- and a green fluorescent protein (GFP) gene (Nav1.4 group, n = 16) or only GFP (n = 18). After 1 week, upstroke velocity and CV were measured by sequential microelectrode recordings at 4 and 7 mM [K(+)] in superfused epicardial slabs. High-density in vivo epicardial activation mapping was performed in a subgroup (8 Nav1.4, 6 GFP) at three to four locations in the border zone. Microscopy and antibody staining confirmed GFP or Nav1.4 expression. RESULTS Infarct sizes were similar between groups (30.6% +/- 3% of left ventricle mass, mean +/- standard error of the mean). Longitudinal CV was greater in Nav1.4 than in GFP sites (58.5 +/- 1.8 vs. 53.3 +/- 1.2 cm/s, 20 and 15 sites, respectively; P <.05). Transverse CV was not different between the groups. In tissue slabs, dV/dt(max) was higher and CV was greater in Nav1.4 than in control at 7 mM [K(+)] (P <.05). Immunohistochemical Nav1.4 staining was seen at the longitudinal ends of the myocytes. CONCLUSION Nav1.4 channels in myocardium surviving 1 week infarction increases longitudinal but not transverse CV, consistent with the increased dV/dt(max) and with the cellular localization of Nav1.4.
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Affiliation(s)
- Ruben Coronel
- Experimental Cardiology Group, Center for Heart Failure Research, Academic Medical Center, Amsterdam, The Netherlands.
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Wang W, Gao J, Entcheva E, Cohen IS, Gordon C, Mathias RT. A transmural gradient in the cardiac Na/K pump generates a transmural gradient in Na/Ca exchange. J Membr Biol 2010; 233:51-62. [PMID: 20130849 DOI: 10.1007/s00232-010-9224-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 01/08/2010] [Indexed: 10/19/2022]
Abstract
We previously demonstrated a transmural gradient in Na/K pump current (I (P)) and [Na(+)]( i ), with the highest maximum I (P) and lowest [Na(+)]( i ) in epicardium. The present study examines the relationship between the transmural gradient in I (P) and Na/Ca exchange (NCX). Myocytes were isolated from canine left ventricle. Whole-cell patch clamp was used to measure current generated by NCX (I (NCX)) and inward background calcium current (I (ibCa)), defined as inward current through Ca(2+) channels less outward current through Ca(2+)-ATPase. When resting myocytes from endocardium (Endo), midmyocardium (Mid) or epicardium (Epi) were studied in the same conditions, I (NCX) was the same and I (ibCa) was zero. Moreover, Western blots were consistent with NCX protein being uniform across the wall. However, the gradient in [Na(+)]( i ), with I (ibCa) = 0, should create a gradient in [Ca(2+)]( i ). To test this hypothesis, we measured resting [Ca(2+)]( i ) using two methods, based on either transport or the Ca(2+)-sensitive dye Fura2. Both methods demonstrated a significant transmural gradient in resting [Ca(2+)]( i ), with Endo > Mid > Epi. This gradient was eliminated by exposing Epi to sufficient ouabain to partially inhibit Na/K pumps, thus increasing [Na(+)]( i ) to values similar to those in Endo. These data support the existence of a transmural gradient for Ca(2+) removal by NCX. This gradient is not due to differences in expression of NCX; rather, it is generated by a transmural gradient in [Na(+)]( i ), which is due to a transmural gradient in plasma membrane expression of the Na/K pump.
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Affiliation(s)
- Wei Wang
- Department of Physiology and Biophysics, SUNY at Stony Brook, NY 11794-8661, USA
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Kelly DJ, Rosen AB, Schuldt AJT, Kochupura PV, Doronin SV, Potapova IA, Azeloglu EU, Badylak SF, Brink PR, Cohen IS, Gaudette GR. Increased myocyte content and mechanical function within a tissue-engineered myocardial patch following implantation. Tissue Eng Part A 2009; 15:2189-201. [PMID: 19231971 DOI: 10.1089/ten.tea.2008.0430] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During the past few years, studies involving the implantation of stem cells, chemical factors, and scaffolds have demonstrated the ability to augment the mammalian heart's native regenerative capacity. Scaffolds comprised of extracellular matrix (ECM) have been used to repair myocardial defects. These scaffolds become populated with myocytes and provide regional contractile function, but quantification of the myocyte population has not yet been conducted. The purpose of this study was to quantitate the myocyte content within the ECM bioscaffold and to correlate this cell population with the regional mechanical function over time. Xenogenic ECM scaffolds derived from porcine urinary bladder were implanted into a full-thickness, surgically induced, right ventricular-free wall defect in a dog model. Zero, 2, and 8 weeks following implantation, regional function and myocyte content were determined in each patch region. Regional function did not significantly increase from 0 to 2 weeks. At 8 weeks, however, regional stroke work increased to 3.7 +/- 0.7% and systolic contraction increased to 4.4 +/- 1.2%. The myocyte content also significantly increased during that period generating a linear relationship between regional function and myocyte content. In conclusion, ECM used as a myocardial patch increases both the regional function and the myocyte content over time. The mechanical function generated in the patch region is correlated with the quantity of local tissue myocytes.
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Affiliation(s)
- Damon J Kelly
- 1 Institute for Molecular Cardiology, Stony Brook University , Stony Brook, New York, USA
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Valiunas V, Kanaporis G, Valiuniene L, Gordon C, Wang HZ, Li L, Robinson RB, Rosen MR, Cohen IS, Brink PR. Coupling an HCN2-expressing cell to a myocyte creates a two-cell pacing unit. J Physiol 2009; 587:5211-26. [PMID: 19736302 DOI: 10.1113/jphysiol.2009.180505] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
We examined whether coupling of a ventricular myocyte to a non-myocyte cell expressing HCN2 could create a two-cell syncytium capable of generating sustained pacing. Three non-myocyte cell types were transfected with the mHCN2 gene and used as sources of mHCN2-induced currents. They were human mesenchymal stem cells and HEK293 cells, both of which express connexin43 (Cx43), and HeLa cells transfected with Cx43. Cell-cell coupling between heterologous pairs increased with time in co-culture, and hyperpolarization of the myocyte induced HCN2 currents, indicating current transfer from the mHCN2-expressing cell to the myocyte via gap junctions. The magnitude of the HCN2 currents recorded in myocytes increased with increasing junctional conductance. Once a critical level of electrical cell-cell coupling between myocytes and mHCN2 transfected cells was exceeded spontaneous action potentials were generated at frequencies of approximately 0.6 to 1.7 Hz (1.09 +/- 0.05 Hz). Addition of carbenoxolone (200 microM), a gap junction channel blocker, to the media stopped spontaneous activity in heterologous cell pairs. Carbenoxolone washout restored activity. Blockade of HCN2 currents by 100 microM 9-amino-1,2,3,4-tetrahydroacridine (THA) stopped spontaneous activity and subsequent washout restored it. Neither THA nor carbenoxolone affected electrically stimulated action potentials in isolated single myocytes. In summary, the inward current evoked in the genetically engineered (HCN2-expressing) cell was delivered to the cardiac myocyte via gap junctions and generated action potentials such that the cell pair could function as a pacemaker unit. This finding lays the groundwork for understanding cell-based biological pacemakers in vivo once an understanding of delivery and target cell geometry is defined.
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Affiliation(s)
- V Valiunas
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
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Abstract
Osteogenesis imperfecta (OI) is a rare inheritable disorder of connective tissue. While musculoskeletal abnormalities are well known, cardiovascular involvement is rare. Aortic root dilation is the most common cardiovascular manifestation. OI preferentially affects the left-sided heart valves, for unclear reasons, leading to aortic and mitral regurgitation. Valve replacement surgery carries a unique set of issues in this population, and fewer than 40 cases have been reported. We report a case of chronic severe aortic regurgitation in a patient with OI complicated by the development of a flail aortic valve leaflet and presenting with a transient ischemic attack. The patient subsequently underwent successful combined bioprosthetic aortic valve replacement and coronary artery bypass grafting. We review the literature on valvular disease and other cardiovascular manifestations in OI and the related surgical considerations relevant to this patient population.
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Affiliation(s)
- Raphael E Bonita
- Division of Cardiology, Department of Medicine, Thomas Jefferson University Hospital, Jefferson Medical College, Philadelphia, Pennsylvania, USA
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Lu Z, Jiang YP, Wang W, Xu XH, Mathias RT, Entcheva E, Ballou LM, Cohen IS, Lin RZ. Loss of cardiac phosphoinositide 3-kinase p110 alpha results in contractile dysfunction. Circulation 2009; 120:318-25. [PMID: 19597047 DOI: 10.1161/circulationaha.109.873380] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Phosphoinositide 3-kinase (PI3K) p110alpha plays a key role in insulin action and tumorigenesis. Myocyte contraction is initiated by an inward Ca(2+) current (I(Ca,L)) through the voltage-dependent L-type Ca(2+) channel (LTCC). The aim of this study was to evaluate whether p110alpha also controls cardiac contractility by regulating the LTCC. METHODS AND RESULTS Genetic ablation of p110alpha (also known as Pik3ca), but not p110beta (also known as Pik3cb), in cardiac myocytes of adult mice reduced I(Ca,L) and blocked insulin signaling in the heart. p110alpha-null myocytes had a reduced number of LTCCs on the cell surface and a contractile defect that decreased cardiac function in vivo. Similarly, pharmacological inhibition of p110alpha decreased I(Ca,L) and contractility in canine myocytes. Inhibition of p110beta did not reduce I(Ca,L). CONCLUSIONS PI3K p110alpha but not p110beta regulates the LTCC in cardiac myocytes. Decreased signaling to p110alpha reduces the number of LTCCs on the cell surface and thus attenuates I(Ca,L) and contractility.
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Affiliation(s)
- Zhongju Lu
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794-8151, USA
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