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 β-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-β-cell regeneration properties.