Comparison of Insulin Secretion between Human Adult and Fetal Pancreatic Islets

Background, objectives: The aim of this study was to compare insulin secreting capacity of human adult and fetal pancreatic islets in order to establish which one is more suitable for transplantation in IDDM patients.Methods: Both adult and fetal islets were cultured in RPMI 1640 medium for 7 days (short-term cultivation) under conventional static culture. Insulin secreting capacity was expressed as stimulation index after stimulation with low and high glucose concentration (1.6 mM/L and 16.7 mM/L, respectively).Results: Adult islets had greater stimulation index on day 1 than on day 7 (703.60±2.89% and 72.21±0.58%, respectively), p<0.01, indicating the loss of functional capacity on the 7th day. Fetal islets, on the other hand, showed slightly increased secretory ability on day 7 compared to day one (395.58±0.12% and 371.52±0.107%, respectively), with statistically significant difference (p<0.01). Comparing stimulation indexes of adult and fetal islets on day 1 and day 7, we established that adult islets had greater values on day 1 than fetal islet, p>0.05. Fetal islets had greater stimulation index on day 7 than adult ones and difference is statistically significant (p<0.001).Conclusions: Based on analyzed results, we concluded that adult islets showed decreased functional ability of insulin secretion in response to glucose stimulation during 7-day cultivation, while fetal ones had slightly increased secretory capacity under the same conditions. These data indicate that fetal tissue cultured in elevated glucose levels is better adapted to culture conditions, while adult tissue loses its functional ability for adequate response on glucose stimulation during 7-day cultivation.