Figure 2.

Anatomical location, differentiation capability and markers of intestinal stem cells: epithelial turnover occurs every 5–7 d in the colon and every 3–5 d in the small intestine. In the small bowel Lgr5 crypt base columnar stem cells coexist with Paneth cells at the crypt base and they generate transit-amplifying (TA) cells, occupying the rest of the crypt. TA cells differentiate into different functional cells on the villi, replacing the epithelial cells lost via anoikis. The +4 stem cells seem to be able of restoring the Lgr5+ CBC stem cell compartment following injury. In the colon Lgr5+ stem cells at the crypt base generate TA cells, which occupy the lower part of the crypt. TA cells differentiate into the mature lineages located on the surface epithelium. CBC cells and 4SC express different series of markers, which are listed on the right panel.