Changes in appetite hormone-producing enteroendocrine cells in the C57BL/6 mouse stomach during ageing

Loss of appetite amongst the elderly population is common and can lead to malnutrition, contributing to the frailty of older individuals. Gut hormones, produced by enteroendocrine cells (ECs) of the intestinal mucosa, play a key role in appetite regulation, and also in gastrointestinal functions such as gastric emptying. Alteration to gut hormone levels in ageing has been reported in some previous studies. Ghrelin, produced by a subpopulation of ECs of the stomach, stimulates appetite, while other peptides, including somatostatin, produced by different stomach ECs, decreases appetite. Here, we investigated possible changes in the numbers of ghrelin- and somatostatin-immunoreactive (IR) ECs in the stomach of male C57BL/6 mice at 4-5, 12-13, 18-19 and 24-25 months of age. Stomach mass and tissue morphology were also measured. No significant changes in stomach mass, muscle thickness or mucosal area were seen, although the greatest stomach mass was seen in 18 month animals. Ghrelin-IR cell density tended to be greater in the fundus than the pylorus (except in the oldest animals), and did not change significantly during ageing. In contrast, somatostatin-IR cell density was similar in both stomach regions but significantly decreased in the fundus of 24-25 month old animals. Somatostatin delays gastric emptying and inhibits ghrelin release. These results indicate that changes in the EC populations of the mammalian stomach may occur during ageing, and may contribute to alterations in gastrointestinal functions and appetite seen in many old people