Growing new kidneys in situ.

One novel solution to the shortage of human organs available for transplantation envisions "growing" new organs in situ via xenotransplantation of developing primordia from animal embryos. Renal primordia (metanephroi) transplanted into animal hosts undergo organogenesis in situ, become vascularized by blood vessels of host origin, and exhibit excretory function. Metanephroi can be stored in vitro prior to transplantation and can be transplanted across both concordant (rat-to-mouse) and highly disparate (pig-to-rodent) xenogeneic barriers. Here we review studies exploring the therapeutic potential for renal organogenesis post-transplantation of kidney primordia.