Xenograft of Microencapsulated Sertoli Cells Reverses T1DM in NOD Mice by Inducing Neogenesis of Beta-Cells

Background. Sertoli cells (SCs) provide an immunoprotective environment to pancreatic islet grafts for treatment of insulin-dependent diabetes. Aim of this work was to verify whether intraperitoneal graft of SCs, enveloped in barium alginate-based microcapsules, would reverse overt spontaneous diabetes in nonobese diabetic (NOD) mice by eliciting generation of newly formed functional islets beta-cells. Methods. Microcapsules were prepared, according to our method, by a mono air-jet device system and thereafter examined as far as (a) SC morphology by light microscopy; (b) SC viability by fluorescence microscopy; (c) SC in vitro function; and (d) SC in vivo function, as quoted by diabetes reversal in the NOD mice, were concerned. Results. SCs containing microcapsules exhibited excellent morphology, viability, and function, and when grafted into the NOD's, they induced stable reversion of the disease in 81% of the cases. The treated mice showed dramatic increase in regulatory T lymphocytes (Treg) when compared with control diabetic NOD's treated with empty capsules only. Histologic examination of pancreata retrieved from the SC-transplanted animals showed total disappearance of insulitis, with appearance of new islets, as shown by immunocytochemistry; restored ability of the islets to produce insulin, glucagon, and somatostatin; and finally, increased expression of key transcriptional factors such as neurogenin 3. Conclusions. SCs, enveloped in barium alginate-based microcapsules, showed no long-term loss of their functional and morphological properties in vitro or in vivo. Xenograft of microencapsulated-SC-induced reversal of spontaneous diabetes in the majority of the treated NOD mice, based on SC-related powerful immunomodulatory and pro-beta-cell regeneration properties.