Paneth cells in intestinal physiology and pathophysiology

Figure 1 Normal small intestinal crypts with basal orientated Paneth cells. A: Paneth cells are characterised by their apical located granules (arrows). Between Paneth cells undifferentiated progenitor cells are found. In the normal Lamina propria mucosae a mixed population of immune cells and stroma resident cells is found; B: Occasionally, Paneth cells at the bottom of small intestinal crypts are mixed up with enteroendocrine cells (arrow). They are characterised by basal located granules. In the upper part of the crypt, a mitotic figure is shown.

Figure 2 Differentiation of Paneth cells and Notch inhibition. Normal ileal mouse mucosa with normal crypts and Paneth cells: HE staining (A) and alcian-PAS staining (B). Arrows indicate Paneth cells. Ileal mouse tissues after treatment with dibenzazepine show an increase in secretory cells in the crypts with differentiation of Paneth cell-like epithelia (arrows): HE staining (C) and alcian-PAS staining (D).

Figure 3 Examples of Paneth cell metaplasia throughout the intestinal tract. A: Paneth cell metaplasia (arrows) in Barrett mucosa. Squamous epithelia of the oesophagus are marked with an arrowhead; B: Chronic atrophic gastritis with Paneth cell metaplasia (arrow); C: Paneth cell metaplasia (arrows) of Brunner’s gland. In the upper part, small intestinal mucosa and secretory ducts are shown (arrowheads); D: Colon mucosa in ulcerative colitis with disturbed crypt architecture, increased numbers of stroma infiltrating inflammatory cells, and Paneth cell metaplasia (arrowheads); E: Higher magnification of ulcerative colitis-associated Paneth cell metaplasia (arrows) in colon mucosa as demonstrated in (D); F: Paneth cell metaplasia (arrows) in tubular adenoma of the colon with low-grade dysplasia.