Relationship between islet angiogenesis and the positive effect of islet neogenesis-associated protein pentadecapeptide (INGAP-PP) upon B-cell function.

FLORES LE; ROMAN CL; MAIZTEGUI B; GAGLIARDINO JJ

Barcelona

Congreso; 49th EASD Annual Meeting; 2013

EASD

Background and aims: Islet neogenesis-associated protein pentadecapeptide (INGAP-PP) administration to normal rats increases their β-cell mass and function, but its mechanism of action remains unclear. On the other hand, embryonic β-cell differentiation needs the presence of endothelial cells, the vascular endothelial growth factor-A (VEGF-A) and integrin β. The aim of the present work was to study whether the effect of INGAP-PP upon β-cell mass and function is associated to a similar effect upon islet angiogenesis. Materials and methods: Adult male Wistar rats were intraperitoneally injected for 10 days with saline solution (control group, C) or INGAP-PP (500 μg/day; intervention Group, I). At the end of the treatment period, glucose tolerance test (GTT) was performed in some animals from both groups while other rats were sacrificied and bled to measure plasma glucose, insulin and trilgliceryde (TG) concentration. Homeostatic model assessment-insulin resistance (HOMA-IR) and - β cell function (HOMA- β) were also calculated. Glucose-stimulated insulin secretion (GSIS), DNA content and levels of gene expression (qPCR and western blot) of Pancreatic and duodenal homeobox 1 (Pdx1), neurogenin 3, integrin β1, VEGF-A, VEGF-Receptor 2 (VEGF-R2), laminin β1 and insulin were measured on islets isolated from both experimental groups. Statistical data analysis was performed using the Students T-test and differences were considered significant when P value