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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.

Background: Bone marrow mesenchymal stem cells (MSCs) are currently being investigated in preclinical and clinical settings because of their multipotent differentiative capacity or, alternatively, their immunosuppressive function. The aim of this study was to evaluate dental pulp (DP) as a potential source of MSCs instead of bone marrow (BM)., Methods: Flow cytometric analysis showed that DP-MSCs and BM-MSCs were equally SH2, SH3, SH4, CD29 and CD 166 positive. The in vitro proliferative kinetics of MSCs were measured by 3H-thymidine incorporation uptake. The immunosuppressive function of MSCs was then tested by coculturing PHA-stimulated allogeneic T cells with or without MSCs for 3 days., Results: BM-MSCs could be differentiated in vitro into osteogenic, chondrogenic and adipogenic lineages. DP-MSCs showed osteogenic and adipocytic differentiation, but did not differentiate into chondrocytes. Although DP-MSCs grow rapidly in vitro between day 3 and day 8 of culture and then decrease their proliferation by day 15, BM-MSCs have a stable and continuous proliferation over the same period of time. The addition of DP-MSCs or BM-MSCs resulted in 91 +/- 4% and 75 +/- 3% inhibition of T cell response, respectively, assessed by a 3H-thymidine assay., Conclusions: Dental pulp is an easily accessible and efficient source of MSCs, with different kinetics and differentiation potentialities from MSCs as isolated from the bone marrow. The rapid proliferative capacity together with the immunoregulatory characteristics of DP-MSCs may prompt future studies aimed at using these cells in the treatment or prevention of T-cell alloreactivity in hematopoietic or solid organ allogeneic transplantation.