Modification of human islets prior to transplantation may improve long-term clinical outcome in terms of diabetes management, by supporting graft function and reducing the potential for allo-rejection. Intragraft incorporation of stem cells secreting beta (β)-cell trophic and immunomodulatory factors represents a credible approach, but requires suitable culture methods to facilitate islet alteration without compromising integrity. This study employed a three-dimensional rotational cell culture system (RCCS) to achieve modification, preserve function, and ultimately influence immune cell responsiveness to human islets. Islets underwent intentional dispersal and rotational culture-assisted aggregation with amniotic epithelial cells (AEC) exhibiting intrinsic immunomodulatory potential. Reassembled islet constructs were assessed for functional integrity, and their ability to induce an allo-response in discrete T-cell subsets determined using mixed islet:lymphocyte reaction assays. RCCS supported the formation of islet:AEC aggregates with improved insulin secretory capacity compared to unmodified islets. Further, the allo-response of peripheral blood mononuclear cell (PBMC) and purified CD4+ and CD8+ T-cell subsets to AEC-bearing grafts was significantly (p < 0.05) attenuated. Rotational culture enables pre-transplant islet modification involving their integration with immunomodulatory stem cells capable of subduing the allo-reactivity of T cells relevant to islet rejection. The approach may play a role in achieving acute and long-term graft survival in islet transplantation.

Background Pre‐transplant modification of porcine islets may improve their suitability for clinical use in diabetes management by supporting graft function and reducing the potential for xeno‐rejection. The present study investigates intra‐graft incorporation of stem cells that secrete beta (β)‐cell trophic and immunomodulatory factors to preserve function and alter immune cell responsiveness to porcine islets. Methods Isolated porcine islets were maintained in a three‐dimensional rotational cell culture system (RCCS) to facilitate aggregation with human amniotic epithelial cells (AECs). Assembled islet constructs were assessed for functional integrity and ability to avoid xeno‐recognition by CD4+ T‐cells using mixed islet:lymphocyte reaction assays. To determine whether stem cell‐mediated modification of porcine islets provided a survival advantage over native islets, structural integrity was examined in a pig‐to‐mouse islet transplant model. Results Rotational cell culture system supported the formation of porcine islet:AEC aggregates with improved insulin‐secretory capacity compared to unmodified islets, whilst the xeno‐response of purified CD4+ T‐cells to AEC‐bearing grafts was significantly (P < 0.05) attenuated. Transplanted AEC‐bearing grafts demonstrated slower rejection in immune‐competent recipients compared to unmodified islets. Conclusions/interpretation Rotational culture enables pre‐transplant modification of porcine islets by integration with immunomodulatory stem cells capable of subduing xeno‐reactivity to CD4+ T‐cells. This reduces islet rejection and offers translational potential to widen availability and improve the clinical effectiveness of islet transplantation.