Stem Cells and Progenitor Cells

Stem cells are a cell type with three defining properties: they are undifferentiated, are capable of dividing mitotically for a long period of time, and can differentiate into more specialized cell types. Because stem cells give rise to the various tissues, they are valuable tools in studying human development and disease. Their self-renewing properties also have promising applications in various cell-based therapies, such as in tissue regeneration and transplantation. Stem cells can have varying levels of potency, or potential for differentiation. Embryonic stem cells, isolated from the inner mass of a blastocyst are pluripotent and can differentiate into nearly all cell types. Differentiated cell types can also be reprogrammed into pluripotency to yield induced pluripotent stem cells (iPSCs). Non-embryonic or adult stem cells, found among already specialized tissue are multipotent and can differentiate into limited cell types. These include hematopoietic stem cells, mesenchymal stem cells, and neural stem cells among others. Finally, progenitor cells are similar and also arise from stem cells, but are designated for differentiation and can replicate only a limited number of times.