Stereological assessment of engineered tissues and their scaffolds

The main aim of tissue engineering is to improve or replace biological functions of all or any of the four basic tissue types. It often involves the creation of appropriate scaffolds that promote tissue formation. These scaffolds can provide pathways for repair and regeneration. It is therefore vitally important that we fully understand the intimate web of cellular interactions in these constructs if we hope to develop practical devices for functional aids to tissue repair. We have at our disposal a wide variety of stereological tools that can help to provide access to the three-dimensional spatial framework of the biomaterial tissue interface. These methods can enable objective quantitation of structure-function relations. Adequate sampling is central to the stereological approach. This chapter will highlight useful approaches to quantify functionally relevant tissue properties. A key question is what to measure?. The stereological approach makes estimates of parameters of geometrical structures. The parameters include volume, surface area, number, thickness, and spacing. In stereology, the nature or function of the structure is not important. The application of these methods should allow us to better understand host tissue behavior. These methods permit quantitation of the scaffold itself as well as local cell and tissue responses. It is an ideal approach to study the scaffold itself as well as the myriad array of cell and tissue responses. Holes can also be considered as structures. The application of stereological methods has been providing a spatial framework on which to lay physiological and molecular information in neuroscience, reproductive biology, and cancer cell biology. In this chapter, we explore the usefulness of this approach in tissue engineering. The wider use of these methods should allow us to better understand host tissue behavior and allow us to develop more functionally relevant tissue engineering solutions.