The interplay between tissue growth and scaffold degradation in engineered tissue constructs

O’Dea, R. D.; Osborne, J. M.; El Haj, A. J.; Byrne, H. M.; Waters, S. L.

The interplay between tissue growth and scaffold degradation in engineered tissue constructs

Type

Article

Authors

O’Dea, R. D.
Osborne, J. M.
El Haj, A. J.
Byrne, H. M.
Waters, S. L.

KAUST Grant Number

KUK-013-04

Online Publication Date

2012-09-18

Print Publication Date

2013-11

Date

2012-09-18

Abstract

In vitro tissue engineering is emerging as a potential tool to meet the high demand for replacement tissue, caused by the increased incidence of tissue degeneration and damage. A key challenge in this field is ensuring that the mechanical properties of the engineered tissue are appropriate for the in vivo environment. Achieving this goal will require detailed understanding of the interplay between cell proliferation, extracellular matrix (ECM) deposition and scaffold degradation. In this paper, we use a mathematical model (based upon a multiphase continuum framework) to investigate the interplay between tissue growth and scaffold degradation during tissue construct evolution in vitro. Our model accommodates a cell population and culture medium, modelled as viscous fluids, together with a porous scaffold and ECM deposited by the cells, represented as rigid porous materials. We focus on tissue growth within a perfusion bioreactor system, and investigate how the predicted tissue composition is altered under the influence of (1) differential interactions between cells and the supporting scaffold and their associated ECM, (2) scaffold degradation, and (3) mechanotransduction-regulated cell proliferation and ECM deposition. Numerical simulation of the model equations reveals that scaffold heterogeneity typical of that obtained from μCT scans of tissue engineering scaffolds can lead to significant variation in the flow-induced mechanical stimuli experienced by cells seeded in the scaffold. This leads to strong heterogeneity in the deposition of ECM. Furthermore, preferential adherence of cells to the ECM in favour of the artificial scaffold appears to have no significant influence on the eventual construct composition; adherence of cells to these supporting structures does, however, lead to cell and ECM distributions which mimic and exaggerate the heterogeneity of the underlying scaffold. Such phenomena have important ramifications for the mechanical integrity of engineered tissue constructs and their suitability for implantation in vivo. © 2012 Springer-Verlag.

Citation

O’Dea RD, Osborne JM, El Haj AJ, Byrne HM, Waters SL (2012) The interplay between tissue growth and scaffold degradation in engineered tissue constructs. Journal of Mathematical Biology 67: 1199–1225. Available: http://dx.doi.org/10.1007/s00285-012-0587-9.

Acknowledgements

This work was supported by funding from the EPSRC in the form of a Ph.D studentship (RDO) and an Advanced Research Fellowship (SLW). It was also supported by the EPSRC/BBSRC-funded OCISB project BB/D020190/1 (JMO), and based on work supported in part by Award KUK-013-04 made by King Abdullah University of Science and Technology (HMB). We are also grateful to E. Baas, ISTM, Keele University for the provision of experimental data.