Roux-en-Y gastric bypass surgery increases number but not density of CCK-, GLP-1-, 5-HT-, and neurotensin-expressing enteroendocrine cells in rats
Article first published online: 24 OCT 2012
© 2012 Blackwell Publishing Ltd
Neurogastroenterology & Motility
Volume 25, Issue 1, pages e70–e79, January 2013
How to Cite
Mumphrey, M. B., Patterson, L. M., Zheng, H. and Berthoud, H.-R. (2013), Roux-en-Y gastric bypass surgery increases number but not density of CCK-, GLP-1-, 5-HT-, and neurotensin-expressing enteroendocrine cells in rats. Neurogastroenterology & Motility, 25: e70–e79. doi: 10.1111/nmo.12034
- Issue published online: 20 DEC 2012
- Article first published online: 24 OCT 2012
- Received: 4 June 2012 Accepted for publication: 24 September 2012
- bariatric surgery;
- high-fat diet;
- intestinal wall;
Background Roux-en-Y gastric bypass (RYGB) surgery is very effective in reducing excess body weight and improving glucose homeostasis in obese subjects. Changes in the pattern of gut hormone secretion are thought to play a major role, but the mechanisms leading to both changed hormone secretion and beneficial effects remain unclear. Specifically, it is not clear whether changes in the number of hormone-secreting enteroendocrine cells, or changes in the releasing stimuli, or both, are important.
Methods We estimated numbers of enteroendocrine cells after immunohistochemical staining in fixed tissue samples from rats at 10–11 months after RYGB.
Key Results Numbers of glucagon-like peptide-1 (GLP-1) (L-cells, co-expressing peptide YY (PYY)), cholecystokinin (CCK), neurotensin, and 5-HT-immunoreactive cells were significantly increased in the Roux and common limbs, but not the biliopancreatic limb in RYGB rats compared with sham-operated, obese rats fed high-fat diet, and chow-fed controls. This increase was mostly accounted for by general hyperplasia of all intestinal wall layers of the nutrient-perfused Roux and common limbs, and less to increased density of expression. The number of ghrelin cells in the bypassed stomach was not different among the three groups.
Conclusions & Inferences The findings suggest that the number of enteroendocrine cells increases passively as the gut adapts, and that the increased total number of L- and I-cells is likely to contribute to the higher circulating levels of GLP-1, PYY, and CCK, potentially leading to suppression of food intake and stimulation of insulin secretion. Whether changes in releasing stimuli also contribute to altered circulating levels will have to be determined in future studies.