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Elhamshari A, Elkhodary K. Proposing a Caputo-Land System for active tension. Capturing variable viscoelasticity. Heliyon 2024; 10:e26143. [PMID: 38390177 PMCID: PMC10881374 DOI: 10.1016/j.heliyon.2024.e26143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
Accurate cell-level active tension modeling for cardiomyocytes is critical to understanding cardiac functionality on a subject-specific basis. However, cell-level models in the literature fail to account for viscoelasticity and inter-subject variations in active tension, which are relevant to disease diagnostics and drug screening, e.g., for cardiotoxicity. Thus, we propose a fractional order system to model cell-level active tension by extending Land's state-of-the-art model of cardiac contraction. Our approach features the (left) Caputo derivative of six state variables that identify the mechanistic origins of viscoelasticity in a myocardial cell in terms of the thin filament, thick filament, and length-dependent interactions. This proposed CLS is the first of its kind for active tension modeling in cells and demonstrates notable subject-specificity, with smaller mean square errors than the reference model relative to cell-level experiments across subjects, promising greater clinical relevance than its counterparts in the literature by highlighting the contribution of different cellular mechanisms to apparent viscoelastic cell behavior, and how it could vary with disease.
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Affiliation(s)
- Afnan Elhamshari
- The Robotics, Control, and Smart Systems Program, The American University in Cairo, 11835, New Cairo, Egypt
| | - Khalil Elkhodary
- The Department of Mechanical Engineering, The American University in Cairo, 11835, New Cairo, Egypt
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Yoneda K, Kanada R, Okada JI, Watanabe M, Sugiura S, Hisada T, Washio T. A thermodynamically consistent monte carlo cross-bridge model with a trapping mechanism reveals the role of stretch activation in heart pumping. Front Physiol 2022; 13:855303. [PMID: 36160842 PMCID: PMC9498833 DOI: 10.3389/fphys.2022.855303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 07/18/2022] [Indexed: 11/24/2022] Open
Abstract
Changes in intracellular calcium concentrations regulate heart beats. However, the decline in the left ventricular pressure during early diastole is much sharper than that of the Ca2+ transient, resulting in a rapid supply of blood to the left ventricle during the diastole. At the tissue level, cardiac muscles have a distinct characteristic, known as stretch activation, similar to the function of insect flight muscles. Stretch activation, which is a delayed increase in force following a rapid muscle length increase, has been thought to be related to autonomous control in these muscles. In this numerical simulation study, we introduced a molecular mechanism of stretch activation and investigated the role of this mechanism in the pumping function of the heart, using the previously developed coupling multiple-step active stiffness integration scheme for a Monte Carlo (MC) cross-bridge model and a bi-ventricular finite element model. In the MC cross-bridge model, we introduced a mechanism for trapping the myosin molecule in its post-power stroke state. We then determined the rate constants of transitions for trapping and escaping in a thermodynamically consistent manner. Based on our numerical analysis, we draw the following conclusions regarding the stretch activation mechanism: (i) the delayed force becomes larger than the original isometric force because the population of trapped myosin molecules and their average force increase after stretching; (ii) the delayed force has a duration of more than a few seconds owing to a fairly small rate constant of escape from the trapped state. For the role of stretch activation in heart pumping, we draw the following conclusions: (iii) for the regions in which the contraction force decreases earlier than the neighboring region in the end-systole phase, the trapped myosin molecules prevent further lengthening of the myocytes, which then prevents further shortening of neighboring myocytes; (iv) as a result, the contraction forces are sustained longer, resulting in a larger blood ejection, and their degeneration is synchronized.
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Affiliation(s)
- Kazunori Yoneda
- Section Solutions Division, Healthcare Solutions Development Unit, Fujitsu Japan Limited, Shiodome City Center, Tokyo, Japan
| | - Ryo Kanada
- RIKEN Center for Computational Science HPC- and AI-driven Drug Development Platform Division, AI-driven Drug Discovery Collaborative Unit, Kobe, Japan
| | - Jun-ichi Okada
- UT-Heart Inc., Kashiwanoha Campus Satellite, Kashiwa, Japan
- Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha Campus Satellite, Kashiwa, Japan
| | - Masahiro Watanabe
- Section Solutions Division, Healthcare Solutions Development Unit, Fujitsu Japan Limited, Shiodome City Center, Tokyo, Japan
| | - Seiryo Sugiura
- UT-Heart Inc., Kashiwanoha Campus Satellite, Kashiwa, Japan
| | | | - Takumi Washio
- UT-Heart Inc., Kashiwanoha Campus Satellite, Kashiwa, Japan
- Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha Campus Satellite, Kashiwa, Japan
- *Correspondence: Takumi Washio,
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Shintani SA, Yamaguchi S, Takadama H. Real-Time Scanning Electron Microscopy of Unfixed Tissue in Solution using a Deformable and Electron-Transmissive Film. Microscopy (Oxf) 2022; 71:297-301. [PMID: 35711152 PMCID: PMC9535786 DOI: 10.1093/jmicro/dfac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 06/08/2022] [Accepted: 06/14/2022] [Indexed: 11/14/2022] Open
Abstract
It is difficult to use scanning electron microscopy to observe the structure and movement of biological tissue immersed in the solution. To enable such observations, we created a highly deformable and electron-transmissive polyimide film that can withstand the pressure difference between the high-vacuum electron column and the atmospheric-pressure sample chamber. With this film, we used scanning electron microscopy to measure the intrinsic fine structure and movement of the contractile fibers of excised mouse heart immersed in physiological solutions. Our measurements revealed that the excised heart is a dynamic tissue that undergoes relaxation oscillation based on a three-dimensional force balance.
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Affiliation(s)
- Seine A Shintani
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi 487-8501, Japan
| | - Seiji Yamaguchi
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi 487-8501, Japan
| | - Hiroaki Takadama
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi 487-8501, Japan
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Shintani SA. Hyperthermal sarcomeric oscillations generated in warmed cardiomyocytes control amplitudes with chaotic properties while keeping cycles constant. Biochem Biophys Res Commun 2022; 611:8-13. [DOI: 10.1016/j.bbrc.2022.04.055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 04/12/2022] [Indexed: 11/02/2022]
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Shintani SA. Does the Hyperthermal Sarcomeric Oscillations Manifested by Body Temperature Support the Periodic Ventricular Dilation With Each Heartbeat? Front Physiol 2022; 13:846206. [PMID: 35418878 PMCID: PMC8996058 DOI: 10.3389/fphys.2022.846206] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/14/2022] [Indexed: 11/30/2022] Open
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