Figure 2.

Stem-cell numbers vary through the intestinal tract. (A) Mouse in situ hybridisation (ISH). H3-UTP labelled ISH for Lgr5 on well-orientated crypts from a wild-type mouse: (i) proximal small bowel (SB1); (ii) mid-small bowel (SB2); (iii) distal small bowel (SB3); and (iv) colon. Individual cells containing ≥4 silver granules were counted and are highlighted in each picture. (B) Mouse Lgr5+ cell counts. Mean (SEM) Lgr5+ cell counts are shown. Lgr5+ cells are maximal in the SB1 with a slightly reducing number through to the ileum (SB3). A profound drop in Lgr5+ cells is seen in the colon (p<0.001, analysis of variance). Cell numbers were counted in 100 crypts from each region from three different wild-type mice. (C) Human ISH. S³⁵-UTP labelled ISH for LGR5 on human endoscopic biopsy specimens from: (i) duodenum (ii) ileum and (iii) colon of the same patient. LGR5 expression was restricted to the crypt bases and was maximal in the ileum, with only single LGR5+ cells seen in colonic crypts. ISH was carried out on biopsy sections from 7 different patients undergoing normal upper and lower endoscopies.