Immunohistochemical markers of stem/progenitor cells in the developing human kidney.

The aim of this study was to better define, by immunohistochemistry, the molecular markers of renal stem/progenitor cells localized in the different niches of ten human preterm kidneys with gestational age ranging from 11 up to 25 weeks. Our data evidence the existence of multiple stem/progenitor pools in different zones of the human developing kidney that are characterized by different phenotypes: capsular stem cells were EMA (MUC1)+, MDM2+, Vimentin+ and Wnt1+; progenitors of the sub-capsular nephrogenic zone were MDM2+ and Wnt1+; cap mesenchymal cells were EMA (MUC1)+, CD15+, vimentin+, Wt1+, CD10+, Bcl2+, Wnt1+ and PAX2+; interstitial progenitor cells were Vimentin+, Wt1+ and α1Anti-tripsin+. Our data evidence the existence of multiple stem/progenitor cell pools in the fetal and neonatal human kidney. Progenitors of these different pools are characterized by a peculiar phenotype, indicating a different differentiation stage of these renal progenitors. A better knowledge of the molecular markers expressed by renal stem/progenitors might represent a relevant datum for researchers involved in renal regenerative medicine.