Cargando…

An integrated finite element simulation of cardiomyocyte function based on triphasic theory

In numerical simulations of cardiac excitation-contraction coupling, the intracellular potential distribution and mobility of cytosol and ions have been mostly ignored. Although the intracellular potential gradient is small, during depolarization it can be a significant driving force for ion movemen...

Descripción completa

Detalles Bibliográficos
Autores principales: Hatano, Asuka, Okada, Jun-Ichi, Washio, Takumi, Hisada, Toshiaki, Sugiura, Seiryo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611143/
https://www.ncbi.nlm.nih.gov/pubmed/26539124
http://dx.doi.org/10.3389/fphys.2015.00287
_version_ 1782396061992615936
author Hatano, Asuka
Okada, Jun-Ichi
Washio, Takumi
Hisada, Toshiaki
Sugiura, Seiryo
author_facet Hatano, Asuka
Okada, Jun-Ichi
Washio, Takumi
Hisada, Toshiaki
Sugiura, Seiryo
author_sort Hatano, Asuka
collection PubMed
description In numerical simulations of cardiac excitation-contraction coupling, the intracellular potential distribution and mobility of cytosol and ions have been mostly ignored. Although the intracellular potential gradient is small, during depolarization it can be a significant driving force for ion movement, and is comparable to diffusion in terms of net flux. Furthermore, fluid in the t-tubules is thought to advect ions to facilitate their exchange with the extracellular space. We extend our previous finite element model that was based on triphasic theory to examine the significance of these factors in cardiac physiology. Triphasic theory allows us to study the behavior of solids (proteins), fluids (cytosol) and ions governed by mechanics and electrochemistry in detailed subcellular structures, including myofibrils, mitochondria, the sarcoplasmic reticulum, membranes, and t-tubules. Our simulation results predicted an electrical potential gradient inside the t-tubules at the onset of depolarization, which corresponded to the Na(+) channel distribution therein. Ejection and suction of fluid between the t-tubules and the extracellular compartment during isometric contraction were observed. We also examined the influence of t-tubule morphology and mitochondrial location on the electrophysiology and mechanics of the cardiomyocyte. Our results confirm that the t-tubule structure is important for synchrony of Ca(2+) release, and suggest that mitochondria in the sub-sarcolemmal region might serve to cancel Ca(2+) inflow through surface sarcolemma, thereby maintaining the intracellular Ca(2+) environment in equilibrium.
format Online
Article
Text
id pubmed-4611143
institution National Center for Biotechnology Information
language English
publishDate 2015
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-46111432015-11-04 An integrated finite element simulation of cardiomyocyte function based on triphasic theory Hatano, Asuka Okada, Jun-Ichi Washio, Takumi Hisada, Toshiaki Sugiura, Seiryo Front Physiol Physics In numerical simulations of cardiac excitation-contraction coupling, the intracellular potential distribution and mobility of cytosol and ions have been mostly ignored. Although the intracellular potential gradient is small, during depolarization it can be a significant driving force for ion movement, and is comparable to diffusion in terms of net flux. Furthermore, fluid in the t-tubules is thought to advect ions to facilitate their exchange with the extracellular space. We extend our previous finite element model that was based on triphasic theory to examine the significance of these factors in cardiac physiology. Triphasic theory allows us to study the behavior of solids (proteins), fluids (cytosol) and ions governed by mechanics and electrochemistry in detailed subcellular structures, including myofibrils, mitochondria, the sarcoplasmic reticulum, membranes, and t-tubules. Our simulation results predicted an electrical potential gradient inside the t-tubules at the onset of depolarization, which corresponded to the Na(+) channel distribution therein. Ejection and suction of fluid between the t-tubules and the extracellular compartment during isometric contraction were observed. We also examined the influence of t-tubule morphology and mitochondrial location on the electrophysiology and mechanics of the cardiomyocyte. Our results confirm that the t-tubule structure is important for synchrony of Ca(2+) release, and suggest that mitochondria in the sub-sarcolemmal region might serve to cancel Ca(2+) inflow through surface sarcolemma, thereby maintaining the intracellular Ca(2+) environment in equilibrium. Frontiers Media S.A. 2015-10-20 /pmc/articles/PMC4611143/ /pubmed/26539124 http://dx.doi.org/10.3389/fphys.2015.00287 Text en Copyright © 2015 Hatano, Okada, Washio, Hisada and Sugiura. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Physics
Hatano, Asuka
Okada, Jun-Ichi
Washio, Takumi
Hisada, Toshiaki
Sugiura, Seiryo
An integrated finite element simulation of cardiomyocyte function based on triphasic theory
title An integrated finite element simulation of cardiomyocyte function based on triphasic theory
title_full An integrated finite element simulation of cardiomyocyte function based on triphasic theory
title_fullStr An integrated finite element simulation of cardiomyocyte function based on triphasic theory
title_full_unstemmed An integrated finite element simulation of cardiomyocyte function based on triphasic theory
title_short An integrated finite element simulation of cardiomyocyte function based on triphasic theory
title_sort integrated finite element simulation of cardiomyocyte function based on triphasic theory
topic Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611143/
https://www.ncbi.nlm.nih.gov/pubmed/26539124
http://dx.doi.org/10.3389/fphys.2015.00287
work_keys_str_mv AT hatanoasuka anintegratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT okadajunichi anintegratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT washiotakumi anintegratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT hisadatoshiaki anintegratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT sugiuraseiryo anintegratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT hatanoasuka integratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT okadajunichi integratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT washiotakumi integratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT hisadatoshiaki integratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory
AT sugiuraseiryo integratedfiniteelementsimulationofcardiomyocytefunctionbasedontriphasictheory