Stem Cell Potency Definitions

PHOTO: Pluripotent, embryonic stem cells originate as inner cell mass (ICM) cells within a blastocyst. These stem cells can become any tissue in the body, excluding a placenta. Only cells from an earlier stage of the embryo, known as the morula, are totipotent, able to become all tissues in the body and the extraembryonic placenta.

Potency specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.

• Totipotent (a.k.a. omnipotent) stem cells can differentiate into embryonic and extraembryonic cell types. Such cells can construct a complete, viable organism. These cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent.
• Pluripotent stem cells are the descendants of totipotent cells and can differentiate into nearly all cells,i.e. cells derived from any of the three germ layers.
• Multipotent stem cells can differentiate into a number of cells, but only those of a closely related family of cells
• Oligopotent stem cells can differentiate into only a few cells, such as lymphoid or myeloid stem cells.
• Unipotent cells can produce only one cell type, their own,but have the property of self-renewal, which distinguishes them from non-stem cells (e.g., muscle stem cells).