Bridging knowledge gaps on the long road to regeneration: classical models meet stem cell manipulation and bioengineering.

Research into tissue repair and regeneration is fought on many fronts. This article emphasizes that research into therapeutic tissue regeneration depends on diverse concepts and approaches. The interface between classical animal models, such as invertebrates and newts, and new opportunities, such as those afforded by mammalian stem cells, is in many respects unexpected. But this interface may make a reality of medicine's long-held dreams for tissue regeneration and organ replacement.