Adult stem cells seem to have the capacity to “transdifferentiate” into cells of many different tissue types; now further work is needed to establish their role in treating degenerative diseases

The discovery of adult tissue specific stem cells, such as haematopoietic stem cells, which have the ability to “transdifferentiate” into other tissues, has generated much excitement among cellbiologists and transplant clinicians. It opens new avenues for basic biological research by using stem cells from adults as an alternative to stem cells from embryos. It also carries important implications for the treatment of many liver, heart, and neurodegenerative diseases. Despite strong evidence that multipotent stem cells (stem cells with the potential to differentiate into several cell types) reside in many adult organs and can be manipulated in ways that may confer a therapeutic advantage, several questions remain to be addressed before the development of clinical applications. We review recent findings on the “plasticity” of adult stem cells to adopt a fate different from their originally intended one, and we discuss the potential clinical importance of this finding. We also point out some directions for research in the future.