Could tubular interstitium be a source of adult epithelial stem cells?
To the Editor: Although it is admitted that kidney is a restoring organ, to date adult renal stem cells are far to be identified. Two recent reports on this Journal reported that after an ischemic injury, tubular epithelium may be recovered by bone marrow derived cells1 or mesenchymal stem cells.2 In particular, Duffield and Bonventre1 showed an increase in the number of peritubular endothelial cells after ischemia/reperfusion experiments, whereas Lange et al.2 showed absence of labeled mesenchymal stem cells in tubules.These results, in our opinion, are also in agreement with other recent experiments, conducted by Bussolati et al.3 that isolated a clone of CD133+ cells able to differentiate in both endothelial and epithelial tubular cells.The presence of ‘multipotent’ undifferentiated cells in kidney may suggest an intriguing hypothesis. Indeed, in our experience, it is very uncommon to observe by light and electron microscopy elements with morphologic features of undifferentiated/ste
