CD133 and CD24 expression in renal tissue of patients affected by autosomal dominant polcystic kidney disease

Background: Autosomal dominant polycystic kidney disease is a condition mainly character- ized by the progressive development and enlar- gement of cysts in each kidney. In this process a high rate of proliferation and apoptosis of tubu- lar cells has been documented and interpreted as a futile attempt of tissue repair. In considera- tion of the role of stem cells in reparative proc- esses we investigated the presence and local- ization of CD133 + CD24+ renal progenitors in renal ADPKD tissue and cells. Methods: Two normal kidneys and two ADPKD kidneys were examined. CD133 and CD24 expression was in- vestigated by confocal microscopy and immu- noblotting. Furthermore cystic isolated cells and cultured immortalized cells were characterized. Results: CD133 and CD24 have the same local- ization in ADPKD tissues and in normal kidneys: expression is restricted to a subset of epithelial cells (PEC) of Bowman’s capsule and to tubular cells in a focal and segmental pattern. Further- more, in ADPKD tissue, cysts diffusely express CD133 and CD24. According to a quantitative analysis in ADPKD tissue CD133 + CD24 + cells are statistically more expressed in tubules (p < 0.001) and less expressed in the Bowman’s capsule (p = 0.0016) compared to the same lo- calizations in control tissue. Conclusions: CD133 and CD24 antigens, typically expressed by renal epithelial progenitors, are more expressed in ADPKD tubules and highly expressed in ADPKD cysts. Whether CD133 and CD24 expression would signify renal progenitor recruitment or alternatively an expression pattern of the dedif- ferentiation of ADPKD cells remains unclear.