Figure 2

TEM of the renal stem/progenitor cell niche after fixation in GA. Low (a), higher (b) and high (c) magnifications illustrate the interstitial interface (asterisk) at the tip of a CD ampulla labeled by a cross (+). (a) Low magnification illustrates that epithelial stem/progenitor cells within the CD ampulla are separated from mesenchymal stem/progenitor cells by a consistently developed basal lamina and a bright interstitial space (asterisk). Protrusions from mesenchymal stem/progenitor cells line towards the CD ampulla (arrow). (b) Higher magnification shows that a basal lamina at the tip of the CD ampulla borders the interstitial interface. The basal lamina consists of a lamina rara (L.r.), lamina densa (L.d.) and lamina fibroreticularis (L.f.) with single fibers (clear arrow head) protruding to the interstitial space. (c) High magnification depicts the interstitial interface (asterisk) with single tiny fibers of extracellular matrix (clear arrow head). Other compounds cannot be recognized after staining with GA.