Kidney Regeneration: Stem Cells as a New Trend

Renal disease is a major worldwide public health problem that affects one in ten people. Renal failure is caused by the irreversible loss of the structural and functional units of kidney (nephrons) due to acute and chronic injuries. In humans, new nephrons (nephrogenesis) are generated until the 36th week of gestation and no new nephron develops after birth. However, in rodents, nephrogenesis persists until the immediate postnatal period. The postnatal mammalian kidney can partly repair their nephrons. The kidney uses intrarenal and extra-renal cell sources for maintenance and repair. Currently, it is believed that dedifferentiation of surviving tubular epithelial cells and presence of resident stem cells have important roles in kidney repair. Many studies have shown that stem cells obtained from extra-renal sites such as the bone marrow, adipose and skeletal muscle tissues, in addition to umbilical cord and amniotic fluid, have potential therapeutic benefits. This review discusses the main mechanisms of renal regeneration by stem cells after a kidney injury.