Skin stem cell identification and culture : a potential tool for rapid epidermal sheet production and grafting

Stem cells are fascinating. They are a production factory and give rise to the differentiated tissues. During embryonic development, stem cells multiply and differentiate to generate the cellular diversity necessary for the formation of all tissues. The pluripotentiality of embryonic stem cells is very large. Stem cells in the embryo are probably different from those in adults in the sense that some embryonic stem cells are present only transiently and their pluripotentiality is greater than that of adult stem cells which are limited to one compartment, e.g., blood, cutaneous or intestinal epithelial cells. In this chapter, we will concentrate on skin stem cells of postnatal mammals. During the adult life, stem cells are responsible for tissue homeostasis; they proliferate to maintain the number of differentiated cells at a constant level and replace dead cells or cells lost through injury.