Induced Pluripotent Stem Cells

IN STEM CELL jargon, a totipotent stem cell is one that arises very early in development and is capable of generating both extra embryonic (e.g., placenta) and embryonic tissues. In humans these totipotent stem cells are only found during the first few divisions of the fertilized egg. From the inner cell mass, pluripotent stem cells can be isolated that are able to produce any cells within the body. Until very recently, these could only be isolated from early embryos. However, a new technique pioneered by a group in Japan now allows pluripotent stem cells to be generated from adult cells within the body. This work was based on the idea that any cell in the body can be “reprogrammed” to a more primitive state, and ...