Figure 6.

In vivo differentiation of renal tissue-derived CD133+ cells in tubular structures. Undifferentiated CD133+ cells (2 × 10⁶) at passage III were incorporated at 4°C within Matrigel and subcutaneously injected in SCID mice (n = 6). Mice were sacrificed after 15 days and the Matrigel plugs were excised and processed for electron microscopy. a: Toluidine blue-stained semithin section of a longitudinal section through a tubule showing (right) a lumen partially filled by dense material. On the left tangential section shows cells displaying different staining properties that may depend on different stage of differentiation. b: Low-power electron micrograph showing the arrangement of cells around a virtual lumen (L) filled with dense material. c: Apical part of three adjacent cells showing microvilli (_*) and junction complexes (arrows). Original magnifications: ×600 (a); ×6000 (b); ×25,000 (c).