Narrow Results

Tissue engineering can be broadly defined as the combination of biology and engineering to repair or replace lost tissue function. From an industry perspective, the field encompasses implanted biomaterials, cell and tissue transplants and therapies, and even extracorporeal cellular devices. To achieve its goals, tissue engineering must effectively utilize not only multiple aspects of engineering but also several aspects of biology that govern mechanisms of organ development, repair and regeneration. The field has always had a strong focus on application yet the challenge of integrating biological science, engineering and medicine has kept many past efforts from reaching their therapeutic and commercial potential. This chapter covers the evolution of tissue engineering, looking at the change in emphasis from bioengineering to stem cell biology and the potential impact of this shift in focus from an industrial perspective. In addition, we have analyzed four major commercial thrusts from past to present: vascular tissue engineering, cartilage repair, liver-assist devices and skin constructs, paying particular attention to how the biomedical disciplines must be integrated to achieve commercial feasibility and therapeutic success. Each example yields one or more important and practical lessons learnt that could be instructive for most future medical and commercial efforts in tissue engineering.

In vivo animal models are currently the gold standard for testing the capacity of stem/progenitor cells, smart biomaterials and novel growth factors for successful tissue engineering. In vitro models ultimately fail to provide the appropriate physiologically relevant microenvironment and hence animal models are an essential pre-requisite in the translation of any new therapy to the clinic. The aim of this chapter is to consider the available animal models commonly in use for tissue engineering, with a particular focus upon bone and cartilage research. Factors driving the choice of a given animal model are reviewed, according to the requirements of experimental design, hypothesis and the specific parameters to be tested. A number of animal models, together with their respective advantages and limitations are described, ranging from relatively simple experimental designs such as the subcutaneous implant and muscle pouch models, through to the diffusion chamber model and chorioallantoic membrane assay, to the more complex in vivo bioreactors and (arguably the most clinically relevant) bone and cartilage defect models. The need to consider the ethical issues of using animal models and the principles of reduction, replacement and refinement are emphasised in selecting the final experimental model of choice.