Normal Insulin Secretion from Immune-Protected Islets of Langerhans by PEGylation and Encapsulation in the Alginate-Chitosan-PEG

BACKGROUND: Pancreatic islet transplantation is one of the most promising strategies for treating patients with type I diabetes mellitus. OBJECTIVE: We aimed to assess the immunoisolation properties of the multilayer encapsulated islets using alginate-chitosan-PEG for immunoprotection and insulin secretion from the encapsulated islets induced under different glucose concentrations in vitro. MATERIALS AND METHODS: In this study, the islets were isolated from Wistar rats. The biological function (insulin secretion) of the immunoisolated islets following to PEGylation and encapsulation in the alginate-chitosan-PEG, separately, in addition to their immuno-protection in a co-culturing with the lymphocytes isolated from the male C57BL/6 mice were investigated, respectively. RESULTS: Alginate-chitosan-PEG decreased IL-2 secretion from the lymphocytes co-cultured with islets. Also, insulin secretion from the encapsulated and PEGylated groups was stimulated by glucose (i.e., 5.6 and 16.7 mM of glucose, respectively); showed insulin secretion similar to the naked islets, without coating, after 30 and 60 min of incubation. CONCLUSION: In conclusion, encapsulation and PEGylation have no negative effect on the insulin secretion and glucose sensitivity of the islets for all of the groups. Also, encapsulation decreased IL-2 secretion from the lymphocytes.