BACKGROUND: Glucagon-like peptide 1 (GLP-1) contributes to satiety and plays a pivotal role in insulin secretion and glucose homeostasis. Similar to GLP-1, peptide YY (PYY) and cholecystokinin also influence food intake. The secretion of these hormones by enteroendocrine cells along the intestine is modulated by nutrients. Preparations from the Stevia rebaudiana plant, including rebaudioside A, are increasingly being used as noncaloric sweeteners.
OBJECTIVE: We investigated the effects of rebaudioside A on enteroendocrine cells by assessing both cell numbers as well as their secretory capacity in an organoid model.
METHODS: A 2-dimensional organoid model derived from duodenal, jejunal, and ileal crypts of a C57BL/6J mouse was developed and characterized with the use of gene expression and immunofluorescence. We stimulated these organoids with 10 mmol/L rebaudioside A for 1 h and measured their GLP-1, PYY, and cholecystokinin release. We also analyzed the effects of rebaudioside A on gene expression in enteroendocrine cells after an 18-h incubation.
RESULTS: The 2-dimensional organoids contained crypt cells and differentiated villus cells, including enterocytes and goblet and enteroendocrine cells. These enteroendocrine cells stained positive for GLP-1, PYY, and serotonin. The cultured 2-dimensional organoids maintained their location-specific gene expression patterns. Compared with the control, rebaudioside A induced GLP-1 secretion 1.7-fold in the duodenum (P < 0.01), 2.2-fold in the jejunum (P < 0.01), and 4.3-fold in the ileum (P < 0.001). PYY release was increased by rebaudioside A 3-fold in the ileum compared with the control (P < 0.05). Long-term (18-h) stimulation with the sweetener induced the expression of the enteroendocrine-specific markers chromogranin A, glucagon, Pyy, and cholecystokinin 3.5- (P < 0.001), 3.5- (P < 0.001), 3.8- (P < 0.05), and 6.5-fold (P < 0.001), respectively.
CONCLUSIONS: These results show novel ex vivo effects of rebaudioside A on enteroendocrine cells of the mouse small intestine and highlight potentially new applications for rebaudioside A in metabolic diseases.
