A multi-scale continuum model of skeletal muscle mechanics predicting force enhancement based on actin-titin interaction
| Autor: | Thomas Heidlauf, Thomas Klotz, Christian Bleiler, Oliver Röhrle, Ekin Altan, Tobias Siebert, Christian Rode |
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| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Sarcomeres Constitutive equation macromolecular substances Isometric exercise Sarcomere Models Biological Biomechanical Phenomena 03 medical and health sciences 0302 clinical medicine medicine Animals Computer Simulation Connectin Muscle Skeletal Actin Physics Continuum mechanics biology Mechanical Engineering Skeletal muscle Mechanics Actins 030104 developmental biology medicine.anatomical_structure Modeling and Simulation biology.protein Titin Stress Mechanical 030217 neurology & neurosurgery Biotechnology Protein Binding |
| Zdroj: | Biomechanics and modeling in mechanobiology. 15(6) |
| ISSN: | 1617-7940 |
| Popis: | Although recent research emphasises the possible role of titin in skeletal muscle force enhancement, this property is commonly ignored in current computational models. This work presents the first biophysically based continuum-mechanical model of skeletal muscle that considers, in addition to actin-myosin interactions, force enhancement based on actin-titin interactions. During activation, titin attaches to actin filaments, which results in a significant reduction in titin's free molecular spring length and therefore results in increased titin forces during a subsequent stretch. The mechanical behaviour of titin is included on the microscopic half-sarcomere level of a multi-scale chemo-electro-mechanical muscle model, which is based on the classic sliding-filament and cross-bridge theories. In addition to titin stress contributions in the muscle fibre direction, the continuum-mechanical constitutive relation accounts for geometrically motivated, titin-induced stresses acting in the muscle's cross-fibre directions. Representative simulations of active stretches under maximal and submaximal activation levels predict realistic magnitudes of force enhancement in fibre direction. For example, stretching the model by 20 % from optimal length increased the isometric force at the target length by about 30 %. Predicted titin-induced stresses in the muscle's cross-fibre directions are rather insignificant. Including the presented development in future continuum-mechanical models of muscle function in dynamic situations will lead to more accurate model predictions during and after lengthening contractions. |
| Databáze: | OpenAIRE |
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