Distribution and co-expression patterns of specific cell markers of enteroendocrine cells in pig gastric epithelium
Although the pig is an accepted model species for human digestive physiology, no previous study of the pig gastric mucosa and gastric enteroendocrine cells has investigated the parallels between pig and human. In this study, we have investigated markers for each of the classes of gastric endocrine cells, gastrin, ghrelin, somatostatin, 5-hydroxytryptamine, histidine decarboxylase, and PYY cells in pig stomach. The lining of the proximal stomach consisted of a collar of stratified squamous epithelium surrounded by gastric cardiac glands in the fundus. This differs considerably from human that has only a narrow band of cardiac glands at its entrance, surrounded by a fundic mucosa consisting of oxyntic glands. However, the linings of the corpus and antrum are similar in pig and human. Likewise, the endocrine cell types are similar and similarly distributed in the two species. As in human, gastrin cells were almost exclusively in the antrum, ghrelin cells were most abundant in the oxyntic mucosa and PYY cells were rare. In the pig, 70% of enterochromaffin-like (ECL) cells in the antrum and 95% in the fundus contained 5-hydroxytryptamine (5-HT), higher proportions than in human. Unlike the enteroendocrine of the small intestine, most gastric enteroendocrine cells (EEC) did not contain colocalised hormones. This is similar to human and other species. We conclude that the pig stomach has substantial similarity to human, except that the pig has a protective lining at its entrance that may reflect the difference between a pig diet with hard abrasive components and the soft foods consumed by humans.
KeywordsStomach Gut hormones Protective epithelium Ghrelin Enterochromaffin-like cells
We thank Maree Cox and Jeremy Cottrell for assistance in tissue harvesting and Melinda Goga and Iain Burchill for assistance with preparation for histology. Confocal imaging was performed at the Biological Optical Microscopy Platform, University of Melbourne.
This work was financially supported by NIH (SPARC) grant ID # OT2OD023847 (PI Terry Powley) to JBF.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
Procedures were approved by the University of Melbourne Animal Ethics Committee (ethics approval number 1714291). All applicable National and Institutional guidelines for the care and use of animals were followed.
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