Tissues are equipped with reasonable strategies for re-pair and regeneration and the renal proximal tubule （PT）is no exception. New information has become availableon the mode of PT regeneration in mammals. Unliketh...Tissues are equipped with reasonable strategies for re-pair and regeneration and the renal proximal tubule （PT）is no exception. New information has become availableon the mode of PT regeneration in mammals. Unlikethe intestinal epithelium with a high rate of turnovermaintained by the stem cell system, the kidney has lowturnover under normal physiological conditions. The PTseems to be maintained physiologically by hyperplasia,a regenerating system with self-renewal of mature tu-bular cells. This mode of regeneration is advantageousfor effective replenishment of randomly isolated andeliminated tubular cells by self-renewal of adjacentcells. On the other hand, it has been suggested thatdedifferentiation of mature tubular cells plays a role inregeneration after acute kidney injury. Recent studiesemploying genetic labeling and DNA-labeling tech-niques have confrmed that the proliferation of preex-isting injured mature tubular cells contributes mainlyto PT regeneration in ischemic reperfusion injury. Thismode of regeneration is beneficial with regard to therapid reparation of focally injured tubules often inducedby ischemic reperfusion injury. What happens, howeverwhen the PT is homogeneously injured with almost noremaining surviving cells？ Is the PT equipped with another backup regeneration system, e.g., the stem cell system？ Is it possible that certain types of renal injuries evoke a stem cell response whereas others do not？ This review focuses on all three possible modes of tis-sue regeneration （compensatory hyperplasia, dediffer-entiation and stem cell system） in mammals and their involvement in PT regeneration in health and disease.展开更多
基金Supported by A Grant-In-Aid for Scientific Research(CNo.22590884)from the Ministry of Education,Culture,Sports,Science,and Technology of Japan
文摘Tissues are equipped with reasonable strategies for re-pair and regeneration and the renal proximal tubule （PT）is no exception. New information has become availableon the mode of PT regeneration in mammals. Unlikethe intestinal epithelium with a high rate of turnovermaintained by the stem cell system, the kidney has lowturnover under normal physiological conditions. The PTseems to be maintained physiologically by hyperplasia,a regenerating system with self-renewal of mature tu-bular cells. This mode of regeneration is advantageousfor effective replenishment of randomly isolated andeliminated tubular cells by self-renewal of adjacentcells. On the other hand, it has been suggested thatdedifferentiation of mature tubular cells plays a role inregeneration after acute kidney injury. Recent studiesemploying genetic labeling and DNA-labeling tech-niques have confrmed that the proliferation of preex-isting injured mature tubular cells contributes mainlyto PT regeneration in ischemic reperfusion injury. Thismode of regeneration is beneficial with regard to therapid reparation of focally injured tubules often inducedby ischemic reperfusion injury. What happens, howeverwhen the PT is homogeneously injured with almost noremaining surviving cells？ Is the PT equipped with another backup regeneration system, e.g., the stem cell system？ Is it possible that certain types of renal injuries evoke a stem cell response whereas others do not？ This review focuses on all three possible modes of tis-sue regeneration （compensatory hyperplasia, dediffer-entiation and stem cell system） in mammals and their involvement in PT regeneration in health and disease.
