Paneth cell
Also known as: Paneth cells
Paneth cells are secretory cells at the base of the small-intestinal crypts, packed with large eosinophilic granules. They release antimicrobial peptides and support the intestinal stem-cell niche.
Overview
Paneth cells are pyramidal, with basal basophilic cytoplasm (rough ER) and large, bright eosinophilic apical granules. They are most numerous in the distal ileum and are normally absent from the colon. Unlike the rest of the epithelium they move down to the crypt base rather than up the villus, and they live for weeks rather than days.
Their granules contain α-defensins (HD5 and HD6), lysozyme, secretory phospholipase A2 and C-type lectins (REG3). Bacterial products and cholinergic stimuli trigger their release. These proteins shape the composition of the microbiota and keep bacteria away from the crypt stem cells. Paneth cells also supply niche signals (Wnt3, EGF and Notch ligands) to their Lgr5⁺ stem-cell neighbours.
- Location
Base of the crypts of Lieberkühn in the small intestine (most numerous in the ileum) and the appendix.
Anatomy
- Histology
Clusters of cells at the crypt base with prominent apical eosinophilic granules, readily seen on H&E.
Function
- Innate antimicrobial defence of the crypt.
- Regulation of the gut microbiota.
- Maintains the intestinal stem-cell niche.
- Secretions
α-Defensins, lysozyme, phospholipase A2 and REG3 lectins.
Clinical significance
Crohn disease
Variants of NOD2 and the autophagy gene ATG16L1 impair Paneth-cell granule handling and defensin secretion. This weakens the antimicrobial barrier and is thought to contribute to ileal Crohn disease.
Paneth cell metaplasia
Paneth cells appearing in the distal colon indicate chronic mucosal injury, as in long-standing ulcerative colitis.
Compiled from standard anatomy and physiology references — see the Digestive System sources. For education only; not medical advice.