Stem cells

Publisher Summary This chapter defines stem cells and their properties. It identifies the major differences between embryonic and adult stem cells. Stem cells can be defined by two properties: the ability to make identical copies of themselves and the ability to form other cell types of the body. These properties are also referred to as “stemness.” Stem cells may potentially provide an unlimited supply of cells that can form any of the hundreds of specialized cells in the body. It is because of these properties that stem cells are an interesting cell source for tissue engineers. Stem cells can be divided into two main groups: embryonic and adult or somatic stem cells. Embryonic stem cells are responsible for embryonic and fetal development and growth. In the human body, adult stem cells are responsible for growth, tissue maintenance and regeneration and repair of diseased or damaged tissue. Embryonic stem cells do not exist in the body. When cells are isolated from the inner cell mass of the blastocyst, they can be massively expanded in the laboratory, while maintaining their pluripotency. Adult stem cells are undifferentiated cells, which reside in differentiated tissues.