On the biomechanics of in vitro epithelial cell populations

The spatial-temporal organisation of growing epithelial cell populations in vitro is studied by a mathematical model that is designed to allow a quantitative comparison with experiments. For this purpose a three-dimensional single-cell based, lattice-free model is developed. The model is able to explicitly account for the conservation of the cell volume, for cell-cell and cell-substrate interaction, and for the visco elastic properties of the individual cells. Each model input variable is an experimentally measurable quantity hence the model parameters can vary within small parameter ranges only.

The effect of changes of cell-kinetic parameters and parameters that characterize cell-cell and cell-matrix interactions is investigated in order to identify those parameters that determine the macroscopic growth kinetics of the cell populations. As demonstrated the model also allows the evaluation of extra-cellular matrix modifications including modifications of viscoelastic properties, and of the spatial structure and composition of the matrix. The results represent the first step towards models of complex biological tissues as single- or multilayered epithelia. Examples are the formation of the epithelial barrier of skin and of the oral mucosa, and the macroscopic self-organisation processes in the intestinal mucosa.