Fig. 1

Morphology of USCs. a Immediately after seeding (d0), urine samples show different contents of squamous cells, ranging from only few cells to complete coverage of the surface (from left to right panel). Representative pictures of four different donors are shown. b Approximately 3 days after seeding, the formation of colonies could be observed. The variability in size and morphology between donors, as well as between two samples from the same donor are shown. c Approximately 10 days (d10) after seeding, the cells reached confluence. Even within two different samples from the same donor, differences in cell morphology could be observed at his stage. d After ten PDs on average USCs stopped proliferation and showed the typical senescent morphology. Samples from two different donors are depicted