LAUSR

The decrease in the number of resident progenitor cells with age was shown for several organs. Such a loss is associated with a decline in regenerative capacity and a greater vulnerability of organs to injury. However, experiments evaluating the number of progenitor cells in the kidney during aging have not been performed until recently. Our study tried to address the change in the number of renal progenitor cells with age. Experiments were carried out on young and old transgenic nestin-green fluorescent protein (GFP) reporter mice, since nestin is suggested to be one of the markers of progenitor cells. We found that nestin+ cells in kidney tissue were located in the putative niches of resident renal progenitor cells. Evaluation of the amount of nestin+ cells in the kidneys of different ages revealed a multifold decrease in the levels of nestin+ cells in old mice. In vitro experiments on primary cultures of renal tubular cells showed that all cells including nestin+ cells from old mice had a lower proliferation rate. Moreover, the resistance to damaging factors was reduced in cells obtained from old mice. Our data indicate the loss of resident progenitor cells in kidneys and a decrease in renal cells proliferative capacity with aging.