Repairing organs: lessons from intestine and liver

• Intestine and liver share common principles in damage-induced regeneration.
• Facultative reserve stem cells arise from differentiated cell populations.
• Common niche signals control stem cell maintenance and differentiation.
• In vitro simulation of niche signals generates transplantable stem cell cultures.

The concept of organ regeneration has fascinated humanity from ancient mythology to modern science fiction. Recent advances offer the potential to soon bring such technology within the grasp of clinical medicine. Rapidly expanding insights into the intrinsic repair processes of the intestine and liver have uncovered significant plasticity in epithelial tissues. Harnessing this knowledge, researchers have recently created culture systems that enable the expansion of stem cells into transplantable tissue in vitro. Here we discuss how the growing tool set of stem cell biology can bring organ repair from fictitious narrative to medical practice.