[Plasticity of stem cells: a change of paradigm?]

Until a few years ago, an interest in stem cells, mostly of hematopoietic origin, was limited to a relatively small representation of scientists and clinicians seeking to understand the role of these rare cells in tissue homeostasis and to utilize their remarkable potential to regenerate an adult tissue following transplantation. Over the last few years, an ability of bone marrow-, brain-, muscle- and other tissue-derived stem cells to branch off, move between tissues and contribute to their repair was discovered. According to this novel view, at least a subset of stem cells may alter their fate in a manner that is more plastic and dynamic than previously thought, causing a fascination with these cells to spread to nearly all clinical disciplines. Expectations are high: stem cells are considered a future remedy for major diseases of our civilization. There are more questions raised than answers, and pressure grows to extend the knowledge and accelerate its implementation.