ABSTRACT
In our study, we focused on the role of the distal ileum as a main endocrine actor in relation to the pancreas. We investigated the effects of intestinally released hormones on the pancreas in terms of type 2 diabetes mellitus (T2DM) improvement, as a main effect of bariatric surgeries. To specifically study the importance of the ileum, we used an experimental surgical model performed in healthy Wistar rats. After preduodenal transposition of the ileum, we analyzed the histology and enterohormonal cells of the intestine. We measured the plasma level of several hormones and effectors in this enteropancreatic axis. We used a surgical control (Sham) group and a surgical group, where ileum preduodenal transposition (PDIT) was performed. We measured basal glycemia and serum levels of several incretins, including GLP-1, PYY, and GIP, and we performed a glucose overdose test. After two test periods, the basal glycemia and glucose overdose results were not different between groups, however, the PDIT group had significantly increased expression of GLP-1, with increased cellular release in the ileum and duodenum compared with the Sham group. Both plasma GIP levels and GIP tissue expression were decreased in the PDIT group compared with the sham group. There were no differences in PPY hormone levels. The ileum crypts and villi of the PDIT group showed improvement in histological parameters. We concluded that model animals had an altered transposed ileum related to the enterohormonal adaptation of the ileum. Our results indicated that the ileum is important in the hormonal control of the enteropancreatic axis.
ABSTRACT
OBJECTIVE: The aim of this study was to clarify the role of the middle gut in the entero-pancreatic axis modification that leads to glucose improvement in the Goto-Kakizaki (GK) rat as a non-obese T2DM model. BACKGROUND: Bariatric surgery is considered an assured solution for type 2 Diabetes (T2DM). Enterohormones such as ghrelin, gastric inhibitory polypeptide and mainly glucagon-like peptide-1 (GLP-1) were recognized as key players in the physiophathological mechanisms associated with entero-pancreatic axis regulation and glucose tolerance improvement. However, the influence of anatomical arrangements post-bariatric surgery on this axis is still debatable. METHOD: To this purpose, 50% of small intestine resections were performed on GK rats (n = 6), preserving the proximal half of the jejunum and the ileum (IR50). Phenotypic and functional changes, such as performance in oral glucose tolerance tests, ileal release of GLP-1, beta-cell sensitivity to GLP-1, beta-cell mass, and turnover were characterized in IR50 and the surgical control group (Sham). RESULTS: The glucose tolerance was improved and ileal release of GLP-1 was enhanced four weeks after IR50 versus the control group rats. Beta-cell mass, beta-cell proliferation, and beta-cell sensitivity to GLP-1 were also increased in the pancreas of IR50 versus the control group rats. CONCLUSION: the jejunal exclusion increases beta-cell-mass and improves glucose tolerance by increasing in GLP-1 expression and number of receptors via the entero-pancreatic axis.