A cell-based framework for modeling cardiac mechanics.

Area of Science:

• Biophysics
• Computational Biology
• Cardiovascular Mechanics

Background:

• Current cardiac mechanics models often homogenize tissue, neglecting individual cell and matrix contributions.
• Understanding microscale mechanics is crucial for accurate simulation of heart function.

Purpose of the Study:

• To develop a novel mathematical and numerical framework for simulating cardiac mechanics at the microscale.
• To explicitly represent individual cardiomyocytes and their extracellular matrix in a 3D geometry.
• To investigate mechanical differences between intracellular and extracellular spaces.

Main Methods:

• Defined a mathematical model on an explicit 3D geometry of cardiomyocytes within a matrix.
• Parametrized the model using experimental data from tissue stretching and shearing.
• Conducted sensitivity analysis to identify key mechanical parameters.

Main Results:

• Extracellular matrix stiffness was found to be the most critical factor for intracellular stress during contraction.
• Strain and stress exhibited a normal-tangential pattern along cell membranes with spatial variations.
• The model successfully scaled to simulate multicellular domains.

Conclusions:

• The developed framework provides a geometrically-based approach to cardiac mechanics, extending continuum models.
• This microscale model offers new insights into cell-cell and cell-matrix interactions in cardiac tissue.
• Explicitly modeling cellular structures enhances the understanding of cardiac mechanical behavior.