Publication Results

Code: 48/2017
Title: Active contraction of cardiac cells: a model for sarcomere dynamics with cooperative interactions
Date: Wednesday 30th August 2017
Author(s) : Regazzoni, F.; Dedè, L.; Quarteroni, A.
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Abstract: We propose a new ODE model for the mechanical activation of cardiac myofilaments, based on explicit spatial representation of nearest-neighbour interactions. Our model is derived from a cooperative Markov Chain model, under the assumption of conditional independence of some sets of events. This assumption, which is physically motivated, allows to drastically reduce the number of degrees of freedom, thus resulting in a considerable computational saving. Indeed, the original Markov Chain model involves a huge number of degrees of freedom and the use of the Monte Carlo method, which notoriously reaches statistical convergence in a slow fashion. With our model, instead, numerical simulations can be carried out by solving a system of ODEs, reducing by more than a factor 10000 the required computational time. Our model is capable of reproducing physiological steady-state force-calcium and force-length relationships with the observed asymmetry in apparent cooperativity near the calcium level producing half activation. A good agreement with experimental measurements under dynamic conditions is also observed, in particular concerning the observed force dependent prolongation of twitches and increment in tension development rate.

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Biomechanics and Modeling in Mechanobiology