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Kazemi-Lari MA, Shimkunas R, Jian Z, Hegyi B, Izu L, Shaw JA, Wineman AS, Chen-Izu Y. Modeling Cardiomyocyte Mechanics and Autoregulation of Contractility by Mechano-Chemo-Transduction Feedback. iScience 2022; 25:104667. [PMID: 35860762 PMCID: PMC9289640 DOI: 10.1016/j.isci.2022.104667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/22/2022] [Accepted: 06/20/2022] [Indexed: 11/30/2022] Open
Abstract
The heart pumps blood into circulation against vascular resistance and actively regulates the contractile force to compensate for mechanical load changes. Our experimental data show that cardiomyocytes have a mechano-chemo-transduction (MCT) mechanism that increases intracellular Ca2+ transient to enhance contractility in response to increased mechanical load. This study advances the cardiac excitation- Ca2+ signaling-contraction (E-C) coupling model on conceptual and technical fronts. First, we developed analytical and computational models to perform 3-dimensional mechanical analysis of cardiomyocytes contracting in a viscoelastic medium under mechanical load. Next, we proposed an MCT feedback loop in the E-C coupling dynamic system to shift the feedforward paradigm of cardiac E-C coupling to an autoregulation model. Our combined modeling and experimental studies reveal that MCT enables autoregulation of E-C coupling and contractility in single cardiomyocytes, which underlies the heart’s intrinsic autoregulation in compensatory response to load changes in order to maintain the stroke volume and cardiac output. Excitation-contraction (E-C) coupling has mechano-chemo-transduction (MCT) feedback MCT feedback enables autoregulation of E-C coupling when contracting under load Models for 3D mechanical analyses of cardiomyocytes contraction Shifts the paradigm of cardiac E-C coupling from feedforward to autoregulation model
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Wilde C, Mitgau J, Suchý T, Schoeneberg T, Liebscher I. Translating the Force - mechano-sensing GPCRs. Am J Physiol Cell Physiol 2022; 322:C1047-C1060. [PMID: 35417266 DOI: 10.1152/ajpcell.00465.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Incorporating mechanical cues into cellular responses allows us to experience our direct environment. Specialized cells can perceive and discriminate between different physical properties such as level of vibration, temperature, or pressure. Mechanical forces are abundant signals that also shape general cellular responses such as cytoskeletal rearrangement, differentiation, or migration and contribute to tissue development and function. The molecular structures that perceive and transduce mechanical forces are specialized cytoskeletal proteins, cell junction molecules, and membrane proteins such as ion channels and metabotropic receptors. G protein-coupled receptors (GPCRs) have attracted attention as metabotropic force receptors as they are among the most important drug targets. This review summarizes the function of mechano-sensitive GPCRs, specifically, the angiotensin II type 1 receptor and adrenergic, apelin, histamine, parathyroid hormone 1, and orphan receptors, focusing particularly on the advanced knowledge gained from adhesion-type GPCRs. We distinguish between shear stress and cell swelling/stretch as the two major types of mechano-activation of these receptors and contemplate the potential contribution of the force-from-lipid and force-from-tether models that have previously been suggested for ion channels.
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Affiliation(s)
- Caroline Wilde
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Germany
| | - Jakob Mitgau
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Germany
| | - Tomás Suchý
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Germany
| | - Torsten Schoeneberg
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Germany
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Lookin O, Khokhlova A, Myachina T, Butova X, Cazorla O, de Tombe P. Contractile State Dependent Sarcomere Length Variability in Isolated Guinea-Pig Cardiomyocytes. Front Physiol 2022; 13:857471. [PMID: 35444559 PMCID: PMC9013801 DOI: 10.3389/fphys.2022.857471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Cardiomyocytes contract keeping their sarcomere length (SL) close to optimal values for force generation. Transmural heterogeneity in SL across the ventricular wall coordinates the contractility of the whole-ventricle. SL heterogeneity (variability) exists not only at the tissue (macroscale) level, but also presents at the level of a single cardiomyocyte (microscale level). However, transmural differences in intracellular SL variability and its possible dependence on the state of contraction (e.g. end-diastole or end-systole) have not been previously reported. In the present study, we studied three aspects of sarcomere-to-sarcomere variability in intact cardiomyocytes isolated from the left ventricle of healthy guinea-pig: 1) transmural differences in SL distribution between subepi- (EPI) and subendocardial (ENDO) cardiomyocytes; 2) the dependence of intracellular variability in SL upon the state of contraction; 3) local differences in SL variability, comparing SL distributions between central and peripheral regions within the cardiomyocyte. To characterize the intracellular variability of SL, we used different normality tests for the assessment of SL distributions, as well as nonparametric coefficients to quantify the variability. We found that individual SL values in the end-systolic state of contraction followed a normal distribution to a lesser extent as compared to the end-diastolic state of contraction (∼1.3-fold and ∼1.6-fold in ENDO and EPI, respectively). The relative and absolute coefficients of sarcomere-to-sarcomere variability in end-systolic SL were significantly greater (∼1.3-fold) as compared to end-diastolic SL. This was independent of both the transmural region across the left ventricle and the intracellular region within the cardiomyocyte. We conclude that the intracellular variability in SL, which exists in normal intact guinea-pig cardiomyocytes, is affected by the contractile state of the myocyte. This phenomenon may play a role in inter-sarcomere communication in the beating heart.
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Affiliation(s)
- Oleg Lookin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russia
- *Correspondence: Oleg Lookin,
| | - Anastasia Khokhlova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russia
| | - Tatiana Myachina
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russia
| | - Xenia Butova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russia
| | - Olivier Cazorla
- Laboratoire “Physiologie et Médecine Expérimentale du Coeur et des Muscles”, Phymedexp, INSERM—CNRS - Montpellier University, Montpellier, France
| | - Pieter de Tombe
- Laboratoire “Physiologie et Médecine Expérimentale du Coeur et des Muscles”, Phymedexp, INSERM—CNRS - Montpellier University, Montpellier, France
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, United States
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Single cardiomyocytes from papillary muscles show lower preload-dependent activation of force compared to cardiomyocytes from the left ventricular free wall. J Mol Cell Cardiol 2022; 166:127-136. [DOI: 10.1016/j.yjmcc.2022.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 02/05/2022] [Accepted: 02/22/2022] [Indexed: 01/21/2023]
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Khokhlova A, Myachina T, Volzhaninov D, Butova X, Kochurova A, Berg V, Gette I, Moroz G, Klinova S, Minigalieva I, Solovyova O, Danilova I, Sokolova K, Kopylova G, Shchepkin D. Type 1 Diabetes Impairs Cardiomyocyte Contractility in the Left and Right Ventricular Free Walls but Preserves It in the Interventricular Septum. Int J Mol Sci 2022; 23:ijms23031719. [PMID: 35163643 PMCID: PMC8836009 DOI: 10.3390/ijms23031719] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 12/14/2022] Open
Abstract
Type 1 diabetes (T1D) leads to ischemic heart disease and diabetic cardiomyopathy. We tested the hypothesis that T1D differently affects the contractile function of the left and right ventricular free walls (LV, RV) and the interventricular septum (IS) using a rat model of alloxan-induced T1D. Single-myocyte mechanics and cytosolic Ca2+ concentration transients were studied on cardiomyocytes (CM) from LV, RV, and IS in the absence and presence of mechanical load. In addition, we analyzed the phosphorylation level of sarcomeric proteins and the characteristics of the actin-myosin interaction. T1D similarly affected the characteristics of actin-myosin interaction in all studied regions, decreasing the sliding velocity of native thin filaments over myosin in an in vitro motility assay and its Ca2+ sensitivity. A decrease in the thin-filament velocity was associated with increased expression of β-myosin heavy-chain isoform. However, changes in the mechanical function of single ventricular CM induced by T1D were different. T1D depressed the contractility of CM from LV and RV; it decreased the auxotonic tension amplitude and the slope of the active tension–length relationship. Nevertheless, the contractile function of CM from IS was principally preserved.
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Affiliation(s)
- Anastasia Khokhlova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
- Institute of Physics and Technology, Ural Federal University, Mira 19, 620002 Yekaterinburg, Russia
- Correspondence:
| | - Tatiana Myachina
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Denis Volzhaninov
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Xenia Butova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Anastasia Kochurova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Valentina Berg
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Irina Gette
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Gleb Moroz
- Institute of Natural Sciences and Mathematics, Ural Federal University, Mira 19, 620002 Yekaterinburg, Russia;
| | - Svetlana Klinova
- Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers, Popova 30, 620014 Yekaterinburg, Russia; (S.K.); (I.M.)
| | - Ilzira Minigalieva
- Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers, Popova 30, 620014 Yekaterinburg, Russia; (S.K.); (I.M.)
| | - Olga Solovyova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
- Institute of Physics and Technology, Ural Federal University, Mira 19, 620002 Yekaterinburg, Russia
- Institute of Natural Sciences and Mathematics, Ural Federal University, Mira 19, 620002 Yekaterinburg, Russia;
| | - Irina Danilova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Ksenia Sokolova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Galina Kopylova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
| | - Daniil Shchepkin
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Yekaterinburg, Russia; (T.M.); (D.V.); (X.B.); (A.K.); (V.B.); (I.G.); (O.S.); (I.D.); (K.S.); (G.K.); (D.S.)
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Kosta S, Dauby PC. Frank-Starling mechanism, fluid responsiveness, and length-dependent activation: Unravelling the multiscale behaviors with an in silico analysis. PLoS Comput Biol 2021; 17:e1009469. [PMID: 34634040 PMCID: PMC8504729 DOI: 10.1371/journal.pcbi.1009469] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 09/22/2021] [Indexed: 11/18/2022] Open
Abstract
The Frank-Starling mechanism is a fundamental regulatory property which underlies the cardiac output adaptation to venous filling. Length-dependent activation is generally assumed to be the cellular origin of this mechanism. At the heart scale, it is commonly admitted that an increase in preload (ventricular filling) leads to an increased cellular force and an increased volume of ejected blood. This explanation also forms the basis for vascular filling therapy. It is actually difficult to unravel the exact nature of the relationship between length-dependent activation and the Frank-Starling mechanism, as three different scales (cellular, ventricular and cardiovascular) are involved. Mathematical models are powerful tools to overcome these limitations. In this study, we use a multiscale model of the cardiovascular system to untangle the three concepts (length-dependent activation, Frank-Starling, and vascular filling). We first show that length-dependent activation is required to observe both the Frank-Starling mechanism and a positive response to high vascular fillings. Our results reveal a dynamical length dependent activation-driven response to changes in preload, which involves interactions between the cellular, ventricular and cardiovascular levels and thus highlights fundamentally multiscale behaviors. We show however that the cellular force increase is not enough to explain the cardiac response to rapid changes in preload. We also show that the absence of fluid responsiveness is not related to a saturating Frank-Starling effect. As it is challenging to study those multiscale phenomena experimentally, this computational approach contributes to a more comprehensive knowledge of the sophisticated length-dependent properties of cardiac muscle. It is commonly admitted that the length-dependent activation is the cellular property underlying the Frank-Starling mechanism. However, it is challenging to assess the cardiac cell length in vivo, and to link it to system-level variables. In this study, we investigated the relationship between length-dependent activation (LDA), the Frank-Starling mechanism, and vascular filling therapy using a multiscale model of the cardiovascular system. We showed that the Frank-Starling mechanism is a multiscale, dynamical and LDA-driven phenomenon involving essential connections between the three cellular, ventricular and cardiovascular scales. We also demonstrated that the response to vascular filling therapy is similarly multiscale and LDA-driven, and that afterload is an important factor to account for when trying to predict the system fluid responsiveness.
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Affiliation(s)
- Sarah Kosta
- GIGA–In Silico Medicine, University of Liège, Liège, Belgium
- * E-mail:
| | - Pierre C. Dauby
- GIGA–In Silico Medicine, University of Liège, Liège, Belgium
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7
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Khokhlova A, Konovalov P, Iribe G, Solovyova O, Katsnelson L. The Effects of Mechanical Preload on Transmural Differences in Mechano-Calcium-Electric Feedback in Single Cardiomyocytes: Experiments and Mathematical Models. Front Physiol 2020; 11:171. [PMID: 32256377 PMCID: PMC7091561 DOI: 10.3389/fphys.2020.00171] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 02/13/2020] [Indexed: 11/13/2022] Open
Abstract
Transmural differences in ventricular myocardium are maintained by electromechanical coupling and mechano-calcium/mechano-electric feedback. In the present study, we experimentally investigated the influence of preload on the force characteristics of subendocardial (Endo) and subepicardial (Epi) single ventricular cardiomyocytes stretched by up to 20% from slack sarcomere length (SL) and analyzed the results with the help of mathematical modeling. Mathematical models of Endo and Epi cells, which accounted for regional heterogeneity in ionic currents, Ca2+ handling, and myofilament contractile mechanisms, showed that a greater slope of the active tension–length relationship observed experimentally in Endo cardiomyocytes could be explained by greater length-dependent Ca2+ activation in Endo cells compared with Epi ones. The models also predicted that greater length dependence of Ca2+ activation in Endo cells compared to Epi ones underlies, via mechano-calcium-electric feedback, the reduction in the transmural gradient in action potential duration (APD) at a higher preload. However, the models were unable to reproduce the experimental data on a decrease of the transmural gradient in the time to peak contraction between Endo and Epi cells at longer end-diastolic SL. We hypothesize that preload-dependent changes in viscosity should be involved alongside the Frank–Starling effects to regulate the transmural gradient in length-dependent changes in the time course of contraction of Endo and Epi cardiomyocytes. Our experimental data and their analysis based on mathematical modeling give reason to believe that mechano-calcium-electric feedback plays a critical role in the modulation of electrophysiological and contractile properties of myocytes across the ventricular wall.
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Affiliation(s)
- Anastasia Khokhlova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia.,Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russia
| | - Pavel Konovalov
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia
| | - Gentaro Iribe
- Department of Physiology, Asahikawa Medical University, Hokkaido, Japan.,Department of Cardiovascular Physiology, Okayama University, Okayama, Japan
| | - Olga Solovyova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia.,Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russia
| | - Leonid Katsnelson
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia.,Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russia
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Dokuchaev A, Khamzin S, Solovyova O. In-silico study of age-related ionic remodeling in human ventricular cardiomyocytes. BIO WEB OF CONFERENCES 2020. [DOI: 10.1051/bioconf/20202201024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ageing is one of the dominant risk factors for cardiovascular diseases. A large number of experimental data is collected on the cellular remodeling in the ageing myocardium from mammals, but very little is known about the human cardiomyocytes. We used a combined electro-mechanical model of human ventricular cardiomyocytes and a population of models approach to investigate the variability in the response of cardiomyocytes to age-related changes in model parameters of the ionic currents.
To generate a control model population, we varied 9 ionic parameters and excluded model samples with biomarkers of cellular action potential (AP) and Ca2+ transient (CT) falling outside the physiological ranges. Using the control population of models, we evaluated the response to age-related reduction in the K+ transient outward current, SERCA pump, and an increase in the Na+Ca2+ exchange current and L-type Ca2+ current. Then, we randomly generated 60 age-related sets of the 4 parameters and applied each set to every model in the control population. We showed an increase in the frequency of repolarization anomalies (RA) and critical AP prolongation in the ageing model populations suggesting arrhythmogenic effects of the ionic remodeling. The population based approach allowed us to assess the pro-arrhythmic contribution of the ionic parameters in ageing cardiomyocytes.
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Lookin O, Protsenko Y. Length-Dependent Activation of Contractility and Ca-Transient Kinetics in Auxotonically Contracting Isolated Rat Ventricular Cardiomyocytes. Front Physiol 2019; 10:1473. [PMID: 31920687 PMCID: PMC6917588 DOI: 10.3389/fphys.2019.01473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/14/2019] [Indexed: 11/13/2022] Open
Abstract
Length-dependent activation (LDA) of contraction is an important mechanism of proper myocardial function that is often blunted in diseases accompanied by deficient contractility and impaired calcium homeostasis. We evaluated how the extent of LDA is related to the decreased force in healthy rat myocardium under negative inotropic conditions that affect the calcium cycle. The length-dependent effects on auxotonic twitch and Ca-transient were compared in isolated rat ventricular cardiomyocytes at room temperature (“25C”) and near-physiological temperature (“35C”) in normal Tyrode and at 25°C with thapsigargin-depleted sarcoplasmic reticulum (“25C + Thap”). At the slack length, a similar negative inotropy in “35C” and “25C + Thap” was accompanied by totally different changes in Ca-transient amplitude, time-to-peak, and time-to-decline from peak to 50% amplitude. End-systolic/end-diastolic tension-sarcomere length relationships were obtained for each individual cell, and the ratio of their slopes, the dimensionless Frank-Starling Gain index, was 2.32 ± 0.16, 1.78 ± 0.09, and 1.37 ± 0.06 in “25C,” “35C” and “25C + Thap,” respectively (mean ± S.E.M.). Ca-transient diastolic level and amplitude did not differ between “25C” and “35C” at any SL, but in “35C” it developed and declined significantly faster. In contrast, thapsigargin-induced depletion of SERCA2a significantly attenuated and retarded Ca-transient. The relative amount of Ca2+ utilized by troponin C, evaluated by the integral magnitude of a short-lived component of Ca-transient decline (“bump”), increased by ~25% per each 0.05 μm increase in SL in all groups. The kinetics of the Ca-TnC dissociation, evaluated by the bump time-to-peak, was significantly faster in “35C” and slower in “25C + Thap” vs. “25C” (respectively, 63.7 ± 5.3 and 253.6 ± 8.3% of the value in “25C,” mean ± S.E.M.). In conclusion, a similar inotropic effect can be observed in rat ventricular myocardium under totally different kinetics of free cytosolic calcium. The extent of LDA is not determined by actual peak systolic tension but is regulated by the level of peak systolic calcium and the kinetics of Ca-transient decline which, in turn, are governed by Ca-TnC dissociation and Ca2+ reuptake by the sarcoplasmic reticulum. Altogether, these findings constitute new evidence about the role of the length-dependent modulation of Ca2+ homeostasis in the mechanisms of calcium regulation of contraction and mechano-calcium feedback in the myocardium.
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Affiliation(s)
- Oleg Lookin
- Laboratory of Biological Motility, Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russia.,Center for Fundamental Biotechnology and Bioengineering, Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russia
| | - Yuri Protsenko
- Laboratory of Biological Motility, Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russia
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Takahashi K, Hayashi S, Miyajima M, Omori M, Wang J, Kaihara K, Morimatsu M, Wang C, Chen J, Iribe G, Naruse K, Sokabe M. L-type calcium channel modulates mechanosensitivity of the cardiomyocyte cell line H9c2. Cell Calcium 2019; 79:68-74. [PMID: 30836292 DOI: 10.1016/j.ceca.2019.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 02/01/2019] [Accepted: 02/18/2019] [Indexed: 01/08/2023]
Abstract
The application of mechanical stimuli to cells often induce increases in intracellular calcium, affecting the regulation of a variety of cell functions. Although the mechanism of mechanotransduction-induced calcium increases has not been fully resolved, the involvement of mechanosensitive ion channels in the plasma membrane and the endoplasmic reticulum has been reported. Here, we demonstrate that voltage-gated L-type calcium channels play a critical role in the mechanosensitive calcium response in H9c2 rat cardiomyocytes. The intracellular calcium level in H9c2 cells increased in a reproducible dose-dependent manner in response to uniaxial stretching. The stretch-activated calcium response (SICR) completely disappeared in calcium-free medium, whereas thapsigargin and cyclopiazonic acid, inhibitors of sarcoendoplasmic reticulum calcium ATPase, partially reduced the SICR. These findings suggest that both calcium influx across the cell membrane and calcium release from the sarcoendoplasmic reticulum are involved in the SICR. Nifedipine, diltiazem, and verapamil, inhibitors of L-type calcium channels, reduced the SICR in a dose-dependent manner. Furthermore, small interfering RNA against the L-type calcium channel α1c subunit diminished the SICR dramatically. Nifedipine also diminished the mechanosensitivity of Langendorff-perfused rat heart. These results suggest that the SICR in H9c2 cardiomyocytes involves the activation of L-type calcium channels and subsequent calcium release from the sarcoendoplasmic reticulum.
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Affiliation(s)
- Ken Takahashi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan; Department of Physiology, Nagoya University School of Medicine, Nagoya, 466-8550, Japan.
| | - Shogo Hayashi
- Department of Physiology, Nagoya University School of Medicine, Nagoya, 466-8550, Japan
| | - Mari Miyajima
- Department of Physiology, Nagoya University School of Medicine, Nagoya, 466-8550, Japan
| | - Marei Omori
- Department of Physiology, Nagoya University School of Medicine, Nagoya, 466-8550, Japan
| | - Jing Wang
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan; Department of Cardiology, Qingdao Municipal Hospital, Qingdao, 266001, China
| | - Keiko Kaihara
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Masatoshi Morimatsu
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Chen Wang
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Jian Chen
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan; Department of Pathophysiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
| | - Gentaro Iribe
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Keiji Naruse
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Masahiro Sokabe
- Department of Physiology, Nagoya University School of Medicine, Nagoya, 466-8550, Japan; Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
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11
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Bioenergetic Feedback between Heart Cell Contractile Machinery and Mitochondrial 3D Deformations. Biophys J 2018; 115:1603-1613. [PMID: 30274832 DOI: 10.1016/j.bpj.2018.08.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 08/12/2018] [Accepted: 08/29/2018] [Indexed: 12/21/2022] Open
Abstract
In the heart, mitochondria are arranged in pairs sandwiched between the contractile machinery, which is the major ATP consumer. Thus, in response to the contraction-relaxation cycle of the cell, the mitochondrial membrane should deform accordingly. Membrane deformations in isolated ATP synthesis or in isolated mitochondria affect ATP production. However, it is unknown whether physiological deformation of the mitochondrial membrane in response to the contraction-relaxation cycle can act as a bioenergetic signaling mechanism between ATP demand to supply. We used both experimental and computational tools to reveal whether bioenergetic feedback exists between heart cell contractile machinery and mitochondrial three-dimensional (3D) deformations. We measured the mitochondrial 3D deformation in contracting rabbit cardiac myocytes and used published data on rat cardiac myocytes. These measurements were an input to a novel biophysics model that includes a description of ionic molecules on the mitochondrial membrane, Ca2+ cycling, and mitochondrial membrane stress. As is the case for rat cardiomyocytes, in rabbit cardiomyocytes, the mitochondrial length contracted and expanded with a similar dynamic as the sarcomere length. In contrast, the mitochondrial width expanded and then contracted with a similar dynamic as the mitochondrial length. Differences in the extent of deformation and fractional deformation between the width- and thick-axes were quantified and interpreted as the degree anisotropy between those respective axes. Finally, the model predicts that significant bioenergetic feedback between heart cell contractile machinery and mitochondrial 3D deformations does exist in unloaded rabbit and rat cells. However, this feedback is not a dominant mechanism in ATP supply to demand matching.
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12
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Khokhlova A, Balakina-Vikulova N, Katsnelson L, Iribe G, Solovyova O. Transmural cellular heterogeneity in myocardial electromechanics. J Physiol Sci 2018; 68:387-413. [PMID: 28573594 PMCID: PMC10717105 DOI: 10.1007/s12576-017-0541-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 04/24/2017] [Indexed: 12/22/2022]
Abstract
Myocardial heterogeneity is an attribute of the normal heart. We have developed integrative models of cardiomyocytes from the subendocardial (ENDO) and subepicardial (EPI) ventricular regions that take into account experimental data on specific regional features of intracellular electromechanical coupling in the guinea pig heart. The models adequately simulate experimental data on the differences in the action potential and contraction between the ENDO and EPI cells. The modeling results predict that heterogeneity in the parameters of calcium handling and myofilament mechanics in isolated ENDO and EPI cardiomyocytes are essential to produce the differences in Ca2+ transients and contraction profiles via cooperative mechanisms of mechano-calcium-electric feedback and may further slightly modulate transmural differences in the electrical properties between the cells. Simulation results predict that ENDO cells have greater sensitivity to changes in the mechanical load than EPI cells. These data are important for understanding the behavior of cardiomyocytes in the intact heart.
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Affiliation(s)
- Anastasia Khokhlova
- Ural Federal University, Ekaterinburg, Russia.
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia.
| | - Nathalie Balakina-Vikulova
- Ural Federal University, Ekaterinburg, Russia
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia
| | - Leonid Katsnelson
- Ural Federal University, Ekaterinburg, Russia
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia
| | - Gentaro Iribe
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Olga Solovyova
- Ural Federal University, Ekaterinburg, Russia
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia
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13
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Khokhlova A, Iribe G, Katsnelson L, Naruse K, Solovyova O. The effects of load on transmural differences in contraction of isolated mouse ventricular cardiomyocytes. J Mol Cell Cardiol 2017; 114:276-287. [PMID: 29217431 DOI: 10.1016/j.yjmcc.2017.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/01/2017] [Indexed: 12/31/2022]
Abstract
Mechanical properties of cardiomyocytes from different transmural regions are heterogeneous in the left ventricular wall. The cardiomyocyte mechanical environment affects this heterogeneity because of mechano-electric feedback mechanisms. In the present study, we investigated the effects of the mechanical load (preload and afterload) on transmural differences in contraction of subendocardial (ENDO) and subepicardial (EPI) single cells isolated from the murine left ventricle. Various preloads imposed via axial stretch and afterloads (unloaded and heavy loaded conditions) were applied to the cells using carbon fiber techniques for single myocytes. To simulate experimentally obtained results and to predict mechanisms underlying the cellular response to change in load, our mathematical models of the ENDO and EPI cells were used. Our major findings are the following. Our results show that ENDO and EPI cardiomyocytes have different mechanical responses to changes in preload to the cells. Under auxotonic contractions at low preload (unstretched cells), time to peak contraction (Tmax) and the time constant of [Ca2+]i transient decay were significantly longer in ENDO cells than in EPI cells. An increase in preload (stretched cells) prolonged Tmax in both cell types; however, the prolongation was greater in EPI cells, resulting in a decrease in the transmural gradient in Tmax at high preload. Comparing unloaded and heavy loaded (isometric) contractions of the cells we found that transmural gradient in the time course of contraction is independent of the loading conditions. Our mathematical cell models were able to reproduce the experimental results on the distinct cellular responses to changes in the mechanical load when we accounted for an ENDO/EPI difference in the parameters of cooperativity of calcium activation of myofilaments.
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Affiliation(s)
- Anastasia Khokhlova
- Ural Federal University, Mira 19, 620002 Ekaterinburg, Russia; Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Ekaterinburg, Russia.
| | - Gentaro Iribe
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Shikata cho 2-5-1, 1700-8558 Okayama, Japan
| | - Leonid Katsnelson
- Ural Federal University, Mira 19, 620002 Ekaterinburg, Russia; Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Ekaterinburg, Russia
| | - Keiji Naruse
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Shikata cho 2-5-1, 1700-8558 Okayama, Japan
| | - Olga Solovyova
- Ural Federal University, Mira 19, 620002 Ekaterinburg, Russia; Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya 106, 620049 Ekaterinburg, Russia; Institute of Mathematics and Mechanics, Russian Academy of Sciences, Kovalevskaya 16, 620990 Ekaterinburg, Russia
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14
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Balistreri M, Davis JA, Campbell KF, Da Rocha AM, Treadwell MC, Herron TJ. Effect of Glucose on 3D Cardiac Microtissues Derived from Human Induced Pluripotent Stem Cells. Pediatr Cardiol 2017; 38:1575-1582. [PMID: 28752324 DOI: 10.1007/s00246-017-1698-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/21/2017] [Indexed: 11/29/2022]
Abstract
Maternal hyperglycemia is a risk factor for fetal cardiac anomalies. This study aimed to assess the effect of high glucose on human induced pluripotent stem cell-derived cardiomyocyte self-assembly into 3D microtissues and their calcium handling. Stem cells were differentiated to beating cardiomyocytes using established protocols. On the final day of the differentiation process, cells were treated with control media, 12 mM glucose, or 12 mM mannitol (an osmolality control). Once beating, the cardiac cells were dissociated with trypsin, collected, mixed with collagen, and plated into custom-made silicone micro molds in order to generate 3D cardiac microtissues. A time-lapse microscope took pictures every 4 h to quantify the kinetics of cellular self-assembly of 3D cardiac tissues. Fiber widths were recorded at 4-h intervals and plotted over time to assess cardiomyocyte 3D fiber self-assembly. Microtissue calcium flux was recorded with optical mapping by pacing microtissues at 0.5 and 1.0 Hz. Exposure to high glucose impaired the ability of cardiomyocytes to self-assemble into compact microtissues, but not their ability to spontaneously contract. Glucose-exposed cardiomyocytes took longer to self-assemble and finished as thicker fibers. When cardiac microtissues were paced at 0.5 and 1.0 Hz, those exposed to high glucose had altered calcium handling with shorter calcium transient durations, but larger amplitudes of the calcium transient when compared to controls. Additional studies are needed to elucidate a potential mechanism for these findings. This model provides a novel method to assess the effects of exposures on the cardiomyocytes' intrinsic abilities for organogenesis in 3D.
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Affiliation(s)
- Michael Balistreri
- Department of Obstetrics and Gynecology, Von Voigtlander Women's Hospital, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI, 48109, USA.
| | - Justin A Davis
- Department of Obstetrics and Gynecology, Von Voigtlander Women's Hospital, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI, 48109, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Cardiology, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Katherine F Campbell
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | | | - Marjorie C Treadwell
- Department of Obstetrics and Gynecology, Von Voigtlander Women's Hospital, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI, 48109, USA
| | - Todd J Herron
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Cardiology, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
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15
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Peyronnet R, Bollensdorff C, Capel RA, Rog-Zielinska EA, Woods CE, Charo DN, Lookin O, Fajardo G, Ho M, Quertermous T, Ashley EA, Kohl P. Load-dependent effects of apelin on murine cardiomyocytes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:333-343. [PMID: 28935153 PMCID: PMC5726609 DOI: 10.1016/j.pbiomolbio.2017.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/26/2023]
Abstract
The apelin peptide is described as one of the most potent inotropic agents, produced endogenously in a wide range of cells, including cardiomyocytes. Despite positive effects on cardiac contractility in multicellular preparations, as well as indications of cardio-protective actions in several diseases, its effects and mechanisms of action at the cellular level are incompletely understood. Here, we report apelin effects on dynamic mechanical characteristics of single ventricular cardiomyocytes, isolated from mouse models (control, apelin-deficient [Apelin-KO], apelin-receptor KO mouse [APJ-KO]), and rat. Dynamic changes in maximal velocity of cell shortening and relaxation were monitored. In addition, more traditional indicators of inotropic effects, such as maximum shortening (in mechanically unloaded cells) or peak force development (in auxotonic contracting cells, preloaded using the carbon fibre technique) were studied. The key finding is that, using Apelin-KO cardiomyocytes exposed to different preloads with the 2-carbon fibre technique, we observe a lowering of the slope of the end-diastolic stress-length relation in response to 10 nM apelin, an effect that is preload-dependent. This suggests a positive lusitropic effect of apelin, which could explain earlier counter-intuitive findings on an apelin-induced increase in contractility occurring without matching rise in oxygen consumption.
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Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg · Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, NHLI, Heart Science Centre, UK.
| | - Christian Bollensdorff
- Imperial College London, NHLI, Heart Science Centre, UK; Sidra Medical and Research Center, Qatar Foundation, Qatar
| | | | - Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg · Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, NHLI, Heart Science Centre, UK
| | - Christopher E Woods
- Stanford University Division of Cardiovascular Medicine, Stanford, USA; Palo Alto Medical Foundation, Burlingame, CA, USA
| | - David N Charo
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | - Oleg Lookin
- Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russian Federation
| | - Giovanni Fajardo
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | - Michael Ho
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | | | - Euan A Ashley
- Stanford University Division of Cardiovascular Medicine, Stanford, USA
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg · Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, NHLI, Heart Science Centre, UK
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16
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Khokhlova A, Iribe G, Yamaguchi Y, Naruse K, Solovyova O. Effects of simulated ischemia on the transmural differences in the Frank-Starling relationship in isolated mouse ventricular cardiomyocytes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:323-332. [PMID: 28571718 DOI: 10.1016/j.pbiomolbio.2017.05.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/25/2017] [Accepted: 05/26/2017] [Indexed: 12/26/2022]
Abstract
The electrical and mechanical functions of cardiomyocytes differ in relation to the spatial locations of cells in the ventricular wall. This physiological heterogeneity may change under pathophysiological conditions, providing substrates for arrhythmia and contractile dysfunctions. Previous studies have reported distinctions in the electrophysiological and mechanical responses to ischemia of unloaded subendocardial (ENDO) and subepicardial (EPI) single cardiomyocytes. In this paper, we briefly recapitulated the available experimental data on the ischemia effects on the transmural cellular gradient in the heart ventricles and for the first time evaluated the preload-dependent changes in passive and active forces in ENDO and EPI cardiomyocytes isolated from mouse hearts subjected to simulated ischemia. Combining the results obtained in mechanically loaded contracting cardiomyocytes with data from previous studies, we showed that left ventricular ENDO and EPI cardiomyocytes are different in their mechanical responses to metabolic inhibition. Simulated ischemia showed opposite effects on the stiffness of ENDO and EPI cells and greatly prolonged the time course of contraction in EPI cells than in ENDO cells, thereby changing the normal transmural gradient in the cellular mechanics.
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Affiliation(s)
- Anastasia Khokhlova
- Ural Federal University, 620002, Mira 19, Ekaterinburg, Russia; Institute of Immunology and Physiology, Russian Academy of Sciences, 620049, Pervomajskaya 106, Ekaterinburg, Russia.
| | - Gentaro Iribe
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1700-8558, Shikata Cho 2-5-1, Okayama, Japan
| | - Yohei Yamaguchi
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1700-8558, Shikata Cho 2-5-1, Okayama, Japan
| | - Keiji Naruse
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1700-8558, Shikata Cho 2-5-1, Okayama, Japan
| | - Olga Solovyova
- Ural Federal University, 620002, Mira 19, Ekaterinburg, Russia; Institute of Immunology and Physiology, Russian Academy of Sciences, 620049, Pervomajskaya 106, Ekaterinburg, Russia
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17
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Chen-Izu Y, Izu LT. Mechano-chemo-transduction in cardiac myocytes. J Physiol 2017; 595:3949-3958. [PMID: 28098356 DOI: 10.1113/jp273101] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/15/2016] [Indexed: 12/31/2022] Open
Abstract
The heart has the ability to adjust to changing mechanical loads. The Frank-Starling law and the Anrep effect describe exquisite intrinsic mechanisms the heart has for autoregulating the force of contraction to maintain cardiac output under changes of preload and afterload. Although these mechanisms have been known for more than a century, their cellular and molecular underpinnings are still debated. How does the cardiac myocyte sense changes in preload or afterload? How does the myocyte adjust its response to compensate for such changes? In cardiac myocytes Ca2+ is a crucial regulator of contractile force and in this review we compare and contrast recent studies from different labs that address these two important questions. The 'dimensionality' of the mechanical milieu under which experiments are carried out provide important clues to the location of the mechanosensors and the kinds of mechanical forces they can sense and respond to. As a first approximation, sensors inside the myocyte appear to modulate reactive oxygen species while sensors on the cell surface appear to also modulate nitric oxide signalling; both signalling pathways affect Ca2+ handling. Undoubtedly, further studies will add layers to this simplified picture. Clarifying the intimate links from cellular mechanics to reactive oxygen species and nitric oxide signalling and to Ca2+ handling will deepen our understanding of the Frank-Starling law and the Anrep effect, and also provide a unified view on how arrhythmias may arise in seemingly disparate diseases that have in common altered myocyte mechanics.
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Affiliation(s)
- Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, CA, 95616, USA.,Department of Biomedical Engineering, University of California, Davis, CA, 95616, USA.,Department of Internal Medicine/Division of Cardiology, University of California, Davis, CA, 95616, USA
| | - Leighton T Izu
- Department of Pharmacology, University of California, Davis, CA, 95616, USA
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18
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Woods C, Shang C, Taghavi F, Downey P, Zalewski A, Rubio GR, Liu J, Homburger JR, Grunwald Z, Qi W, Bollensdorff C, Thanaporn P, Ali A, Riemer K, Kohl P, Mochly-Rosen D, Gerstenfeld E, Large S, Ali Z, Ashley E. In Vivo Post-Cardiac Arrest Myocardial Dysfunction Is Supported by Ca2+/Calmodulin-Dependent Protein Kinase II-Mediated Calcium Long-Term Potentiation and Mitigated by Alda-1, an Agonist of Aldehyde Dehydrogenase Type 2. Circulation 2016; 134:961-977. [PMID: 27582424 DOI: 10.1161/circulationaha.116.021618] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 07/21/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND Survival after sudden cardiac arrest is limited by postarrest myocardial dysfunction, but understanding of this phenomenon is constrained by a lack of data from a physiological model of disease. In this study, we established an in vivo model of cardiac arrest and resuscitation, characterized the biology of the associated myocardial dysfunction, and tested novel therapeutic strategies. METHODS We developed rodent models of in vivo postarrest myocardial dysfunction using extracorporeal membrane oxygenation resuscitation followed by invasive hemodynamics measurement. In postarrest isolated cardiomyocytes, we assessed mechanical load and Ca(2) (+)-induced Ca(2+) release (CICR) simultaneously using the microcarbon fiber technique and observed reduced function and myofilament calcium sensitivity. We used a novel fiberoptic catheter imaging system and a genetically encoded calcium sensor, GCaMP6f, to image CICR in vivo. RESULTS We found potentiation of CICR in isolated cells from this extracorporeal membrane oxygenation model and in cells isolated from an ischemia/reperfusion Langendorff model perfused with oxygenated blood from an arrested animal but not when reperfused in saline. We established that CICR potentiation begins in vivo. The augmented CICR observed after arrest was mediated by the activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). Increased phosphorylation of CaMKII, phospholamban, and ryanodine receptor 2 was detected in the postarrest period. Exogenous adrenergic activation in vivo recapitulated Ca(2+) potentiation but was associated with lesser CaMKII activation. Because oxidative stress and aldehydic adduct formation were high after arrest, we tested a small-molecule activator of aldehyde dehydrogenase type 2, Alda-1, which reduced oxidative stress, restored calcium and CaMKII homeostasis, and improved cardiac function and postarrest outcome in vivo. CONCLUSIONS Cardiac arrest and reperfusion lead to CaMKII activation and calcium long-term potentiation, which support cardiomyocyte contractility in the face of impaired postarrest myofilament calcium sensitivity. Alda-1 mitigates these effects, normalizes calcium cycling, and improves outcome.
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Affiliation(s)
- Christopher Woods
- Division of Cardiology, Arrhythmia Section, Palo Alto Medical Foundation, Burlingame, CA
| | - Ching Shang
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Fouad Taghavi
- Department of Cardiothoracic Surgery, Papworth Hospital, Cambridge, UK
| | - Peter Downey
- Division of Cardiology, Columbia University, New York, NY
| | | | - Gabriel R Rubio
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Jing Liu
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | | | - Zachary Grunwald
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Wei Qi
- Division of Cardiology, Columbia University, New York, NY
| | | | - Porama Thanaporn
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Ayyaz Ali
- Department of Cardiothoracic Surgery, Papworth Hospital, Cambridge, UK
| | - Kirk Riemer
- Department of Cardiothoracic Surgery, Stanford University, London, UK
| | - Peter Kohl
- National Heart and Lung Institute, Imperial College, London, UK
| | | | | | - Stephen Large
- Department of Cardiothoracic Surgery, Papworth Hospital, Cambridge, UK
| | - Ziad Ali
- Division of Cardiology, Columbia University, New York, NY
| | - Euan Ashley
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA
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19
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de Tombe PP, Kohl P. Which way to grow? Force over time may be the heart's Dao de jing. Glob Cardiol Sci Pract 2016; 2016:e201621. [PMID: 29043268 PMCID: PMC5642831 DOI: 10.21542/gcsp.2016.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Pieter P de Tombe
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60304, USA
| | - Peter Kohl
- Cardiac Biophysics and Systems Biology, National Heart and Lung Institute, Imperial College London, UK.,Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, and Faculty of Medicine, Albert Ludwigs University Freiburg, Germany
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20
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Capulli AK, MacQueen LA, Sheehy SP, Parker KK. Fibrous scaffolds for building hearts and heart parts. Adv Drug Deliv Rev 2016; 96:83-102. [PMID: 26656602 PMCID: PMC4807693 DOI: 10.1016/j.addr.2015.11.020] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 12/14/2022]
Abstract
Extracellular matrix (ECM) structure and biochemistry provide cell-instructive cues that promote and regulate tissue growth, function, and repair. From a structural perspective, the ECM is a scaffold that guides the self-assembly of cells into distinct functional tissues. The ECM promotes the interaction between individual cells and between different cell types, and increases the strength and resilience of the tissue in mechanically dynamic environments. From a biochemical perspective, factors regulating cell-ECM adhesion have been described and diverse aspects of cell-ECM interactions in health and disease continue to be clarified. Natural ECMs therefore provide excellent design rules for tissue engineering scaffolds. The design of regenerative three-dimensional (3D) engineered scaffolds is informed by the target ECM structure, chemistry, and mechanics, to encourage cell infiltration and tissue genesis. This can be achieved using nanofibrous scaffolds composed of polymers that simultaneously recapitulate 3D ECM architecture, high-fidelity nanoscale topography, and bio-activity. Their high porosity, structural anisotropy, and bio-activity present unique advantages for engineering 3D anisotropic tissues. Here, we use the heart as a case study and examine the potential of ECM-inspired nanofibrous scaffolds for cardiac tissue engineering. We asked: Do we know enough to build a heart? To answer this question, we tabulated structural and functional properties of myocardial and valvular tissues for use as design criteria, reviewed nanofiber manufacturing platforms and assessed their capabilities to produce scaffolds that meet our design criteria. Our knowledge of the anatomy and physiology of the heart, as well as our ability to create synthetic ECM scaffolds have advanced to the point that valve replacement with nanofibrous scaffolds may be achieved in the short term, while myocardial repair requires further study in vitro and in vivo.
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Affiliation(s)
- A K Capulli
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - L A MacQueen
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Sean P Sheehy
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K K Parker
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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21
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Solovyova O, Katsnelson LB, Kohl P, Panfilov AV, Tsaturyan AK, Tsyvian PB. Mechano-electric heterogeneity of the myocardium as a paradigm of its function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:249-54. [PMID: 26713555 PMCID: PMC4821177 DOI: 10.1016/j.pbiomolbio.2015.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/13/2015] [Accepted: 12/16/2015] [Indexed: 01/25/2023]
Abstract
Myocardial heterogeneity is well appreciated and widely documented, from sub-cellular to organ levels. This paper reviews significant achievements of the group, led by Professor Vladimir S. Markhasin, Russia, who was one of the pioneers in studying and interpreting the relevance of cardiac functional heterogeneity.
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Affiliation(s)
- Olga Solovyova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia; Ural Federal University, Ekaterinburg, Russia.
| | - Leonid B Katsnelson
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia; Ural Federal University, Ekaterinburg, Russia.
| | - Peter Kohl
- Research Centre for Cardiovascular Medicine, University of Freiburg, Germany; National Heart and Lung Institute, Imperial College of London, UK.
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22
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Abstract
The heart pumps blood to maintain circulation and ensure the delivery of oxygenated blood to all the organs of the body. Mechanics play a critical role in governing and regulating heart function under both normal and pathological conditions. Biological processes and mechanical stress are coupled together in regulating myocyte function and extracellular matrix structure thus controlling heart function. Here, we offer a brief introduction to the biomechanics of left ventricular function and then summarize recent progress in the study of the effects of mechanical stress on ventricular wall remodeling and cardiac function as well as the effects of wall mechanical properties on cardiac function in normal and dysfunctional hearts. Various mechanical models to determine wall stress and cardiac function in normal and diseased hearts with both systolic and diastolic dysfunction are discussed. The results of these studies have enhanced our understanding of the biomechanical mechanism in the development and remodeling of normal and dysfunctional hearts. Biomechanics provide a tool to understand the mechanism of left ventricular remodeling in diastolic and systolic dysfunction and guidance in designing and developing new treatments.
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Affiliation(s)
- Andrew P. Voorhees
- Department of Mechanical Engineering, The University of Texas at San Antonio, Biomedical Engineering Program, UTSA-UTHSCSA
| | - Hai-Chao Han
- Department of Mechanical Engineering, The University of Texas at San Antonio, Biomedical Engineering Program, UTSA-UTHSCSA
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23
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Schwan J, Campbell SG. Prospects for In Vitro Myofilament Maturation in Stem Cell-Derived Cardiac Myocytes. Biomark Insights 2015; 10:91-103. [PMID: 26085788 PMCID: PMC4463797 DOI: 10.4137/bmi.s23912] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 12/20/2022] Open
Abstract
Cardiomyocytes derived from human stem cells are quickly becoming mainstays of cardiac regenerative medicine, in vitro disease modeling, and drug screening. Their suitability for such roles may seem obvious, but assessments of their contractile behavior suggest that they have not achieved a completely mature cardiac muscle phenotype. This could be explained in part by an incomplete transition from fetal to adult myofilament protein isoform expression. In this commentary, we review evidence that supports this hypothesis and discuss prospects for ultimately generating engineered heart tissue specimens that behave similarly to adult human myocardium. We suggest approaches to better characterize myofilament maturation level in these in vitro systems, and illustrate how new computational models could be used to better understand complex relationships between muscle contraction, myofilament protein isoform expression, and maturation.
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Affiliation(s)
- Jonas Schwan
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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Living cardiac tissue slices: an organotypic pseudo two-dimensional model for cardiac biophysics research. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:314-27. [PMID: 25124067 DOI: 10.1016/j.pbiomolbio.2014.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/02/2014] [Indexed: 11/24/2022]
Abstract
Living cardiac tissue slices, a pseudo two-dimensional (2D) preparation, have received less attention than isolated single cells, cell cultures, or Langendorff-perfused hearts in cardiac biophysics research. This is, in part, due to difficulties associated with sectioning cardiac tissue to obtain live slices. With moderate complexity, native cell-types, and well-preserved cell-cell electrical and mechanical interconnections, cardiac tissue slices have several advantages for studying cardiac electrophysiology. The trans-membrane potential (Vm) has, thus far, mainly been explored using multi-electrode arrays. Here, we combine tissue slices with optical mapping to monitor Vm and intracellular Ca(2+) concentration ([Ca(2+)]i). This combination opens up the possibility of studying the effects of experimental interventions upon action potential (AP) and calcium transient (CaT) dynamics in 2D, and with relatively high spatio-temporal resolution. As an intervention, we conducted proof-of-principle application of stretch. Mechanical stimulation of cardiac preparations is well-established for membrane patches, single cells and whole heart preparations. For cardiac tissue slices, it is possible to apply stretch perpendicular or parallel to the dominant orientation of cells, while keeping the preparation in a constant focal plane for fluorescent imaging of in-slice functional dynamics. Slice-to-slice comparison furthermore allows one to assess transmural differences in ventricular tissue responses to mechanical challenges. We developed and tested application of axial stretch to cardiac tissue slices, using a manually-controlled stretching device, and recorded Vm and [Ca(2+)]i by optical mapping before, during, and after application of stretch. Living cardiac tissue slices, exposed to axial stretch, show an initial shortening in both AP and CaT duration upon stretch application, followed in most cases by a gradual prolongation of AP and CaT duration during stretch maintained for up to 50 min. After release of sustained stretch, AP duration (APD) and CaT duration reverted to shorter values. Living cardiac tissue slices are a promising experimental model for the study of cardiac mechano-electric interactions. The methodology described here can be refined to achieve more accurate control over stretch amplitude and timing (e.g. using a computer-controlled motorised stage, or by synchronising electrical and mechanical events) and through monitoring of regional tissue deformation (e.g. by adding motion tracking).
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25
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Solovyova O, Katsnelson LB, Konovalov PV, Kursanov AG, Vikulova NA, Kohl P, Markhasin VS. The cardiac muscle duplex as a method to study myocardial heterogeneity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:115-28. [PMID: 25106702 PMCID: PMC4210666 DOI: 10.1016/j.pbiomolbio.2014.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 07/25/2014] [Indexed: 12/14/2022]
Abstract
This paper reviews the development and application of paired muscle preparations, called duplex, for the investigation of mechanisms and consequences of intra-myocardial electro-mechanical heterogeneity. We illustrate the utility of the underlying combined experimental and computational approach for conceptual development and integration of basic science insight with clinically relevant settings, using previously published and new data. Directions for further study are identified.
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Affiliation(s)
- O Solovyova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia; Ural Federal University, 19 Mira Str, Ekaterinburg 620002, Russia.
| | - L B Katsnelson
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia
| | - P V Konovalov
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia
| | - A G Kursanov
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia; Ural Federal University, 19 Mira Str, Ekaterinburg 620002, Russia
| | - N A Vikulova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia
| | - P Kohl
- National Heart and Lung Institute, Imperial College of London, Heart Science Centre, Harefield Hospital, Hill End Road, Harefield UB9 6JH, UK; Department of Computer Sciences, University of Oxford, UK
| | - V S Markhasin
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia; Ural Federal University, 19 Mira Str, Ekaterinburg 620002, Russia
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26
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Cardiac tissue structure, properties, and performance: a materials science perspective. Ann Biomed Eng 2014; 42:2003-13. [PMID: 25081385 DOI: 10.1007/s10439-014-1071-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 07/14/2014] [Indexed: 12/24/2022]
Abstract
From an engineering perspective, many forms of heart disease can be thought of as a reduction in biomaterial performance, in which the biomaterial is the tissue comprising the ventricular wall. In materials science, the structure and properties of a material are recognized to be interconnected with performance. In addition, for most measurements of structure, properties, and performance, some processing is required. Here, we review the current state of knowledge regarding cardiac tissue structure, properties, and performance as well as the processing steps taken to acquire those measurements. Understanding the impact of these factors and their interactions may enhance our understanding of heart function and heart failure. We also review design considerations for cardiac tissue property and performance measurements because, to date, most data on cardiac tissue has been obtained under non-physiological loading conditions. Novel measurement systems that account for these design considerations may improve future experiments and lead to greater insight into cardiac tissue structure, properties, and ultimately performance.
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Partridge JB, Smerup MH, Petersen SE, Niederer PF, Anderson RH. Linking left ventricular function and mural architecture: what does the clinician need to know? Heart 2013; 100:1289-98. [PMID: 24310520 DOI: 10.1136/heartjnl-2013-304571] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- John B Partridge
- Eurobodalla Unit, Rural Clinical School of the ANU College of Medicine, Biology & Environment, Batemans Bay, New South Wales, Australia
| | - Morten H Smerup
- Department of Cardiothoracic Surgery T, Aarhus University Hospital, Skejby, Denmark
| | - Steffen E Petersen
- Cardiovascular Biomedical Research Unit at Barts, Centre for Advanced Cardiovascular Imaging, William Harvey Research Institute, National Institute for Health Research, The London Chest Hospital, London, UK
| | - Peter F Niederer
- Biomedical Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Robert H Anderson
- Institute for Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK
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28
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Shaw J, Izu L, Chen-Izu Y. Mechanical analysis of single myocyte contraction in a 3-D elastic matrix. PLoS One 2013; 8:e75492. [PMID: 24098388 PMCID: PMC3789722 DOI: 10.1371/journal.pone.0075492] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 08/15/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Cardiac myocytes experience mechanical stress during each heartbeat. Excessive mechanical stresses under pathological conditions cause functional and structural remodeling that lead to heart diseases, yet the precise mechanisms are still incompletely understood. To study the cellular and molecular level mechanotransduction mechanisms, we developed a new 'cell-in-gel' experimental system to exert multiaxial (3-D) stresses on a single myocyte during active contraction. METHODS Isolated myocytes are embedded in an elastic hydrogel to simulate the mechanical environment in myocardium (afterload). When electrically stimulated, the in-gel myocyte contracts while the matrix resists shortening and broadening of the cell, exerting normal and shear stresses on the cell. Here we provide a mechanical analysis, based on the Eshelby inclusion problem, of the 3-D strain and stress inside and outside the single myocyte during contraction in an elastic matrix. RESULTS (1) The fractional shortening of the myocyte depends on the cell's geometric dimensions and the relative stiffness of the cell to the gel. A slender or softer cell has less fractional shortening. A myocyte of typical dimensions embedded in a gel of similar elastic stiffness can contract only 20% of its load-free value. (2) The longitudinal stress inside the cell is about 15 times the transverse stress level. (3) The traction on the cell surface is highly non-uniform, with a maximum near its ends, showing 'hot spots' at the location of intercalated disks. (4) The mechanical energy expenditure of the myocyte increases with the matrix stiffness in a monotonic and nonlinear manner. CONCLUSION Our mechanical analyses provide analytic solutions that readily lend themselves to parametric studies. The resulting 3-D mapping of the strain and stress states serve to analyze and interpret ongoing cell-in-gel experiments, and the mathematical model provides an essential tool to decipher and quantify mechanotransduction mechanisms in cardiac myocytes.
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Affiliation(s)
- John Shaw
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
| | - Leighton Izu
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
| | - Ye Chen-Izu
- Departments of Biomedical Engineering, Pharmacology, Medicine/Cardiology, University of California Davis, Davis, California, United States of America
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Scimia MC, Hurtado C, Ray S, Metzler S, Wei K, Wang J, Woods CE, Purcell NH, Catalucci D, Akasaka T, Bueno OF, Vlasuk GP, Kaliman P, Bodmer R, Smith LH, Ashley E, Mercola M, Brown JH, Ruiz-Lozano P. APJ acts as a dual receptor in cardiac hypertrophy. Nature 2012; 488:394-8. [PMID: 22810587 PMCID: PMC3422434 DOI: 10.1038/nature11263] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/25/2012] [Indexed: 01/08/2023]
Abstract
Cardiac hypertrophy is initiated as an adaptive response to sustained overload but progresses pathologically as heart failure ensues. Here we report that genetic loss of APJ, a G-protein-coupled receptor, confers resistance to chronic pressure overload by markedly reducing myocardial hypertrophy and heart failure. In contrast, mice lacking apelin (the endogenous APJ ligand) remain sensitive, suggesting an apelin-independent function of APJ. Freshly isolated APJ-null cardiomyocytes exhibit an attenuated response to stretch, indicating that APJ is a mechanosensor. Activation of APJ by stretch increases cardiomyocyte cell size and induces molecular markers of hypertrophy. Whereas apelin stimulates APJ to activate Gαi and elicits a protective response, stretch signals in an APJ-dependent, G-protein-independent fashion to induce hypertrophy. Stretch-mediated hypertrophy is prevented by knockdown of β-arrestins or by pharmacological doses of apelin acting through Gαi. Taken together, our data indicate that APJ is a bifunctional receptor for both mechanical stretch and the endogenous peptide apelin. By sensing the balance between these stimuli, APJ occupies a pivotal point linking sustained overload to cardiomyocyte hypertrophy.
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MESH Headings
- Adipokines
- Animals
- Aorta/pathology
- Apelin
- Apelin Receptors
- Arrestins/deficiency
- Arrestins/genetics
- Arrestins/metabolism
- Blood Pressure
- Cardiomegaly/metabolism
- Cardiomegaly/pathology
- Cardiomegaly/physiopathology
- Cardiomegaly/prevention & control
- Female
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Intercellular Signaling Peptides and Proteins/deficiency
- Intercellular Signaling Peptides and Proteins/genetics
- Intercellular Signaling Peptides and Proteins/metabolism
- Intercellular Signaling Peptides and Proteins/pharmacology
- Male
- Mechanoreceptors/metabolism
- Mechanotransduction, Cellular/drug effects
- Mechanotransduction, Cellular/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/pathology
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- beta-Arrestins
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Affiliation(s)
| | - Cecilia Hurtado
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | - Saugata Ray
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | - Scott Metzler
- Department of Pediatrics, School of Medicine, Stanford University, CA 94304
| | - Ke Wei
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | - Jianming Wang
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | - Chris E. Woods
- Department of Medicine, School of Medicine, Stanford University, CA
| | | | - Daniele Catalucci
- Biomedical and Genetic Research Institute, National Research Council, via Fantoli 16/15, 20138, Milan, and Istituto Clinico Humanitas IRCSS, Rozzano, Italy
| | - Takashi Akasaka
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | | | | | - Perla Kaliman
- Institute of Biomedical Research August Pi i Sunyer (IDIBAPS) Villarroel 170, E-08036 Barcelona, Spain
| | - Rolf Bodmer
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | - Layton H. Smith
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | - Euan Ashley
- Department of Medicine, School of Medicine, Stanford University, CA
| | - Mark Mercola
- Sanford-Burnham Medical Research Institute, Stanford University, CA
| | | | - Pilar Ruiz-Lozano
- Sanford-Burnham Medical Research Institute, Stanford University, CA
- Department of Pediatrics, School of Medicine, Stanford University, CA 94304
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30
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The zebrafish as a novel animal model to study the molecular mechanisms of mechano-electrical feedback in the heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:154-65. [PMID: 22835662 DOI: 10.1016/j.pbiomolbio.2012.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 07/16/2012] [Indexed: 02/07/2023]
Abstract
Altered mechanical loading of the heart leads to hypertrophy, decompensated heart failure and fatal arrhythmias. However, the molecular mechanisms that link mechanical and electrical dysfunction remain poorly understood. Growing evidence suggest that ventricular electrical remodeling (VER) is a process that can be induced by altered mechanical stress, creating persistent electrophysiological changes that predispose the heart to life-threatening arrhythmias. While VER is clearly a physiological property of the human heart, as evidenced by "T wave memory", it is also thought to occur in a variety of pathological states associated with altered ventricular activation such as bundle branch block, myocardial infarction, and cardiac pacing. Animal models that are currently being used for investigating stretch-induced VER have significant limitations. The zebrafish has recently emerged as an attractive animal model for studying cardiovascular disease and could overcome some of these limitations. Owing to its extensively sequenced genome, high conservation of gene function, and the comprehensive genetic resources that are available in this model, the zebrafish may provide new insights into the molecular mechanisms that drive detrimental electrical remodeling in response to stretch. Here, we have established a zebrafish model to study mechano-electrical feedback in the heart, which combines efficient genetic manipulation with high-precision stretch and high-resolution electrophysiology. In this model, only 90 min of ventricular stretch caused VER and recapitulated key features of VER found previously in the mammalian heart. Our data suggest that the zebrafish model is a powerful platform for investigating the molecular mechanisms underlying mechano-electrical feedback and VER in the heart.
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31
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Chuan P, Sivaramakrishnan S, Ashley EA, Spudich JA. Cell-intrinsic functional effects of the α-cardiac myosin Arg-403-Gln mutation in familial hypertrophic cardiomyopathy. Biophys J 2012; 102:2782-90. [PMID: 22735528 DOI: 10.1016/j.bpj.2012.04.049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 04/02/2012] [Accepted: 04/13/2012] [Indexed: 01/27/2023] Open
Abstract
Human familial hypertrophic cardiomyopathy is the most common Mendelian cardiovascular disease worldwide. Among the most severe presentations of the disease are those in families heterozygous for the mutation R403Q in β-cardiac myosin. Mice heterozygous for this mutation in the α-cardiac myosin isoform display typical familial hypertrophic cardiomyopathy pathology. Here, we study cardiomyocytes from heterozygous 403/+ mice. The effects of the R403Q mutation on force-generating capabilities and dynamics of cardiomyocytes were investigated using a dual carbon nanofiber technique to measure single-cell parameters. We demonstrate the Frank-Starling effect at the single cardiomyocyte level by showing that cell stretch causes an increase in amplitude of contraction. Mutant 403/+ cardiomyocytes exhibit higher end-diastolic and end-systolic stiffness than +/+ cardiomyocytes, whereas active force generation capabilities remain unchanged. Additionally, 403/+ cardiomyocytes show slowed relaxation dynamics. These phenotypes are consistent with increased end-diastolic and end-systolic chamber elastance, as well as diastolic dysfunction seen at the level of the whole heart. Our results show that these functional effects of the R403Q mutation are cell-intrinsic, a property that may be a general phenomenon in familial hypertrophic cardiomyopathy.
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Affiliation(s)
- Peiying Chuan
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, USA
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Taberner AJ, Han JC, Loiselle DS, Nielsen PMF, Nielsen PMF. An innovative work-loop calorimeter for in vitro measurement of the mechanics and energetics of working cardiac trabeculae. J Appl Physiol (1985) 2011; 111:1798-803. [PMID: 21903883 DOI: 10.1152/japplphysiol.00752.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We describe a unique work-loop calorimeter with which we can measure, simultaneously, the rate of heat production and force-length work output of isolated cardiac trabeculae. The mechanics of the force-length work-loop contraction mimic those of the pressure-volume work-loops experienced by the heart. Within the measurement chamber of a flow-through microcalorimeter, a trabecula is electrically stimulated to respond, under software control, in one of three modes: fixed-end, isometric, or isotonic. In each mode, software controls the position of a linear motor, with feedback from muscle force, to adjust muscle length in the desired temporal sequence. In the case of a work-loop contraction, the software achieves seamless transitions between phases of length control (isometric contraction, isometric relaxation, and restoration of resting muscle length) and force control (isotonic shortening). The area enclosed by the resulting force-length loop represents the work done by the trabecula. The change of enthalpy expended by the muscle is given by the sum of the work term and the associated amount of evolved heat. With these simultaneous measurements, we provide the first estimation of suprabasal, net mechanical efficiency (ratio of work to change of enthalpy) of mammalian cardiac trabeculae. The maximum efficiency is at the vicinity of 12%.
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Affiliation(s)
- Andrew J Taberner
- Auckland Bioengineering Institute, The Univ. of Auckland, Auckland, New Zealand.
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33
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de Tombe PP, Granzier HL. The cytoskeleton and the cellular transduction of mechanical strain in the heart: a special issue. Pflugers Arch 2011; 462:1-2. [PMID: 21594569 DOI: 10.1007/s00424-011-0976-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 01/15/2023]
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