Stem cell self-renewal: lessons from bone marrow, gut and iPS toward clinical applications.

The hematopoietic stem cell (HSC) is the prototype organ-regenerating stem cell (SC), and by far the most studied type of SC in the body. Currently, HSC-based therapy is the only routinely used SC therapy; however, advances in the field of embryonic SCs and induced pluripotent SCs may change this situation. Interest into in vitro generation of HSCs, including signals for HSC expansion and differentiation from these more primitive SCs, as well as advances in other organ-specific SCs, in particular the intestine, provide promising new applications for SC therapies. Here, we review the basic principles of different SC systems, and on the basis of the experience with HSC-based SC therapy, provide recommendations for clinical application of emerging SC technologies.