Although adult kidney cells are quiescent, enlargement of specific populations of epithelial
cells occurs during repair and adaptive processes. A prerequisite to the development of
regenerative therapeutics is to identify the mechanisms and factors that control the size of
specific populations of renal cells. Unfortunately, in most cases, it is unknown whether the
growth of cell populations results from transdifferentiation or proliferation and whether
proliferating cells derive from epithelial cells or from circulating or resident progenitors. In …