Chapter 7: Stem Cells: An Emerging Field for Medicine¹

The concept of a stem cell as a progenitor cell from which all specialised cells are derived has been in existence for some 150 years. During the latter decades of the 20th century the concept became a reality, when embryonal carcinoma cells, embryonic stem cells, haematopoietic stem cells and mesenchymal stromal cells were all isolated and characterised. A great deal has been understood in recent years concerning the self-renewal and regulation of differentiation of stem cells. When it became clear that stem cells could be cultured in the laboratory and induced to differentiate into selected tissue-specific cells, it was quickly recognised that their therapeutic potential should be explored. It was the hope of many that tissues, injured as a result of trauma or disease, could be regenerated and their function restored. Following the amazing precedent set by bone marrow transplant it was assumed that many intractable diseases would now yield to stem cell therapy. Much effort has been made in evaluating the therapeutic utility of stem cell therapy, but for many diseases a definitive and unambiguous outcome has not yet been seen. This chapter describes the history of discovery of stem cells and the efforts that have been made to explore their use as a new medicine.