What are the key questions about adult stem cells?
Many important questions about adult stem cells remain to be answered. They include:
- How many kinds of adult stem cells exist, and in which tissues do they exist?
- How do adult stem cells evolve during development and how are they maintained in the adult? Are they “leftover” embryonic stem cells, or do they arise in some other way?
- Why do stem cells remain in an undifferentiated state when all the cells around them have differentiated? What are the characteristics of their “niche” that controls their behavior?
- Do adult stem cells have the capacity to transdifferentiate, and is it possible to control this process to improve its reliability and efficiency?
- If the beneficial effect of adult stem cell transplantation is a trophic effect, what are the mechanisms? Is donor cell-recipient cell contact required, secretion of factors by donor cells, or both?
- What are the factors that control adult stem cell proliferation and differentiation?
- What are the factors that stimulate stem cells to relocate to sites of injury or damage, and how can this process be enhanced for better healing?