Paneth cell

Josef Paneth (1857 to 1890)

Paneth granule cells are merocrine glandular cells and are mainly found at the base of the Lieberkühn crypts in the jejunum and ileum. Their density increases in the intestinal mucosa from oral to aboral: in the duodenum they are hardly found. The lifetime of Paneth cells is 18-23 days.

Light microscopically, these cells can be recognized by their reddish-orange granules, which are located at the apical cell pole, in HE staining. These eosinophilic granules contain antimicrobially active substances such as lysozyme, alpha-defensins (DEFA5, DEFA6), tumour necrosis factor-alpha, phospholipase A2 and ECP (Ayabe T et al. 2000). They are secreted upon contact with pathogenic microorganisms. The release of these molecules leads to a strong antimicrobial response directed against bacteria, fungi and some enveloped viruses (Holly MK et al. 2018). Paneth cells thus play an essential role in innate enteric immunity by specifically regulating the composition of the small intestinal bacterial flora (Adolph TE et al. 2013). Microbial pathogens are detected via the Toll-like receptor (TLR).

The regeneration of the intestinal epithelium is initiated by stem cells in the lower third of the crypts. The newly formed cells migrate to the tip of the villi where they are rejected. Their lifespan is about 5 days. Apparently Paneth cells play a supporting role in the continuous regeneration of the epithelium by stem cells.

Singular Paneth cells are also occasionally found under physiological conditions in the area of the fundo-antral border zone and in coecum. These dystrophic Paneth cells are regarded as heteroplasias and do not seem to have any functional significance.

Various gastroenteropathies also lead to the formation of dystopically localized Paneth cells. This can be observed in chronic atrophic gastritis with intestinal metaplasia, in ulcerative and neoplastic changes of the stomach, colon and rectum.

1. Adolph TE et al (2013) Paneth cells as a site of origin for intestinal inflammation. Nature 503:272-276.
2. Ayabe T et al (2000) Secretion of microbicidal alpha-defensins by intestinal Paneth cells in response to bacteria. Nature Immunol 1:113-118.
3. All T (2000): Paneth cells--guardians of the gut cell. Nature Immunol 1:99-100.
4. Herwart F. Otto HF et al. (1972) On the orthology and pathology of Paneth granule cells Quantitative, light and electron microscopic studies in humans. Virchow's archive 356: 187-206
5. Holly MK et al (2018) Paneth Cells during Viral Infection and Pathogenesis. Viruses 10:225.