A novel method to study contraction characteristics of a single cardiac myocyte using carbon fibers

Yasuda, Seiji; Sugiura, Seiryo; Kobayakawa, Naoshi; Fujita, Hideo; Yamashita, Hiroshi; Katoh, K.; Saeki, Yasutake; Kaneko, Hirohiko; Suda, Yoshihisa; Nagai, Ryozo; Sugi, Haruo

doi:10.1152/ajpheart.2001.281.3.h1442

Cited by 67 publications

(62 citation statements)

References 13 publications

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“…We monitored the sarcomere length in isolated rat cardiomyocytes during Ca 2ϩ waves. Hearts were removed from adult male Wistar rats (200 -300 g) that were under pentobarbital sodium anesthesia (50 mg/kg), and the left ventricular myocytes were isolated using enzymatic dissociation as described previously (35). Myocytes were suspended in 1.8 mmol/l Ca 2ϩ HEPES-Tyrode solution (in mmol/l: 137 NaCl, 5.4 KCl, 1.8 CaCl2, 0.5 MgCl2, 0.33 NaH2PO4, 5 HEPES, and 5 glucose, adjusted to pH 7.4 with NaOH at 22°C), transferred to a silicone-coated (Sigmacote; Sigma) glass chamber, and viewed using an inverted microscope (ϫ40 objective, IX71; Olympus).…”

Section: Cicr and Camentioning

confidence: 99%

Three-dimensional simulation of calcium waves and contraction in cardiomyocytes using the finite element method

Okada¹,

Sugiura²,

Nishimura³

et al. 2005

American Journal of Physiology-Cell Physiology

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Section: Cicr and Camentioning

confidence: 99%

Three-dimensional simulation of calcium waves and contraction in cardiomyocytes using the finite element method

Okada¹,

Sugiura²,

Nishimura³

et al. 2005

American Journal of Physiology-Cell Physiology

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“…This CF technique has been used successfully for the characterization of cardiomyocyte electromechanical properties during auxotonic contractions (3,7,34). More recently, Yasuda et al (37), using a modified version of the CF technique, introduced an adaptive force-length (FL) control system. This technique has been used to subject individual cardiomyocytes to near-isometric, nearisotonic, and work-loop style contractions by anchoring one cell end with a stiff CF and dynamically controlling the attachment position of the other, compliant CF (21).…”

mentioning

confidence: 99%

Force-length relations in isolated intact cardiomyocytes subjected to dynamic changes in mechanical load

Iribe¹,

Helmes

Kohl

2007

American Journal of Physiology-Heart and Circulatory Physiology

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Iribe G, Helmes M, Kohl P. Force-length relations in isolated intact cardiomyocytes subjected to dynamic changes in mechanical load. Am J Physiol Heart Circ Physiol 292: H1487-H1497, 2007. First published November 10, 2006; doi:10.1152/ajpheart.00909.2006.-We developed a dynamic force-length (FL) control system for single intact cardiomyocytes that uses a pair of compliant, computer-controlled, and piezo translator (PZT)-positioned carbon fibers (CF). CF are attached to opposite cell ends to afford dynamic and bidirectional control of the cell's mechanical environment. PZT and CF tip positions, as well as sarcomere length (SL), are simultaneously monitored in real time, and passive/active forces are calculated from CF bending. Cell force and length were dynamically adjusted by corresponding changes in PZT position, to achieve isometric, isotonic, or work-loop style contractions. Functionality of the technique was assessed by studying FL behavior of guinea pig intact cardiomyocytes. End-diastolic and end-systolic FL relations, obtained with varying preload and/or afterloads, were near linear, independent of the mode of contraction, and overlapping for the range of end-diastolic SLs tested (1.85-2.05 m). Instantaneous elastance curves, obtained from FL relation curves, showed an afterload-dependent decrease in time to peak elastance and slowed relaxation with both increased preload and afterload. The ability of the present system to independently and dynamically control preload, afterload, and transition between end-diastolic and endsystolic FL coordinates provides a valuable extension to the range of tools available for the study of single cardiomyocyte mechanics, to foster its interrelation with whole heart pathophysiology. single cell mechanics; preload; afterload; time-varying elastance CLASSICALLY, LOAD-DEPENDENT characterization of cardiac mechanics has been conducted in whole heart preparations (25,27). The externally homogeneous mechanical activity at this level (i.e., the whole organ) arises from spatiotemporal integration of the ordered, but intrinsically heterogeneous, activity of cardiac muscle elements (14). Currently, the tools to study mechanical interaction of heterogeneous contractile elements in near-physiological conditions are limited (23), and the vast majority of research on single intact cardiomyocytes is conducted in mechanically unloaded cells (15).

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“…The original model (29) reflects the strong cooperativity typical of the force-pCa relations observed experimentally (4). The values were adjusted to match the shortening data in our experimental study (10) and other parameters found in the literature, such as the rate of isometric force redevelopment in cardiac muscle (2,26), twitch force in intact myocytes (38), and the force-pCa curve in intact cardiac muscle (1) (see Fig. B2, E and F, in supplemental data for this article, which may be found at http://ajpheart.physiology.org/cgi/content/full/ 00425.2004.DC1).…”

Section: Force Production Formulationmentioning

confidence: 99%

“…Indeed, several parameters had to be based on data from permeabilized myocytes at low temperature or from entire cardiac muscle bundles. Recently, a new technique to measure force in intact cardiac myocytes has been developed using special carbon-fiber force transducers (38). With this technical advancement, it is hoped that tests such as force-pCa measurements [using TG (1); see Fig.…”

Section: Model Limitationsmentioning

confidence: 99%

Genetic manipulation of calcium-handling proteins in cardiac myocytes. II. Mathematical modeling studies

Coutu

Metzger

2005

American Journal of Physiology-Heart and Circulatory Physiology

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We developed a mathematical model specific to rat ventricular myocytes that includes electrophysiological representation, ionic homeostasis, force production, and sarcomere movement. We used this model to interpret, analyze, and compare two genetic manipulations that have been shown to increase myocyte relaxation rates, parvalbumin (Parv) de novo expression, and sarco(endo)plasmic reticulum Ca 2ϩ -ATPase (SERCA2a) overexpression. The model was used to seek mechanistic insights into 1) the relative contribution of two mechanisms by which SERCA2a overexpression modifies Ca 2ϩ sequestration, i.e., more pumps and an increase in the SERCA2a-tophospholamban ratio, 2) the mechanisms behind postrest potentiation and how Parv and SERCA2a influence this response, and 3) why Parv myocytes retain their fast kinetics when endogenous SERCA2a is partially impaired by thapsigargin (a condition used to mimic diastolic dysfunction). The model was also utilized to predict whether Parv metal-binding characteristics might be modified to improve diastolic and systolic functions and whether Parv or SERCA2a might affect diastolic Ca 2ϩ levels and myocyte energetics. One outcome of the model was to demonstrate a higher peak and total ATP consumption in SERCA2a myocytes and more even distribution of ATP throughout the cardiac cycle in Parv myocytes. This may have implications for failing hearts that are energetically compromised. mathematical model; rat; parvalbumin; sarco(endo)plasmic reticulum calcium-adenosinetriphosphatase 2aHEART FAILURE affects more than 5,000,000 people in the United States (25). It has been estimated that 40% of heart failure patients exhibit pure diastolic dysfunction (20), a condition characterized by slowing of Ca 2ϩ uptake at the cellular level, increase in stiffness during relaxation at the tissue level, and impaired ventricular filling at the organ level. Alterations in Ca 2ϩ -handling proteins play an important role in diastolic dysfunction (23). Several genetic manipulations have been proposed to restore myocyte Ca 2ϩ -handling function in failing hearts (12), including modification of expression or functionality of sarco(endo)plasmic Ca 2ϩ -ATPase (SERCA2a), phospholamban (PLB), Na ϩ /Ca 2ϩ exchanger (NCX), and parvalbumin (Parv), a specialized Ca 2ϩ buffer (8). In our experimental study (10), we used gene transfer in intact isolated rat adult cardiac myocytes to study, characterize, and compare the effects of SERCA2a overexpression or Parv expression on isolated cardiac myocyte function. We found that when myocytes were subjected to single unloaded contractions, both methods resulted in similar increases in myocyte relaxation rate. However, we established that the response of SERCA2a-expressing myocytes to other conditions, such as ␤-adrenergic stimulation [with isoproterenol (Iso)], diastolic dysfunction [chemically induced with thapsigargin (TG), a SERCA2a inhibitor], or changes in stimulation pacing [during postrest potentiation (PRP) tests], was different from that of Parv-expressing myocytes. The e...

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A novel method to study contraction characteristics of a single cardiac myocyte using carbon fibers

Cited by 67 publications

References 13 publications

Three-dimensional simulation of calcium waves and contraction in cardiomyocytes using the finite element method

Three-dimensional simulation of calcium waves and contraction in cardiomyocytes using the finite element method

Force-length relations in isolated intact cardiomyocytes subjected to dynamic changes in mechanical load

Genetic manipulation of calcium-handling proteins in cardiac myocytes. II. Mathematical modeling studies

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