Rotational culture and integration with amniotic stem cells reduce porcine islet immunoreactivity in vitro and slow xeno‐rejection in a murine model of islet transplantation

Abstract

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.

Shielding islets with human amniotic epithelial cells enhances islet engraftment and revascularization in a murine diabetes model

“…hAECs immunomodulatory properties have been reported, and previous studies have used approaches similar to the one described herein, combining hAECs with islets to modulate the human alloreactivity in vitro and, very recently, in vivo . This suggests that in addition to enhancing vascularization and engraftment, our strategy could protect the graft from immune reactions, allowing to decrease the strength of immunosuppression regimens.…”

Generation of insulin‐secreting organoids: a step toward engineering and transplanting the bioartificial pancreas

“…Moreover, our studies have shown that AECs have a cytoprotective effect on islet cells under hypoxic conditions, mediated by HIF‐1α. In addition to our promising results, others have demonstrated the ability of AECs to dampen the immune response against islets in both an allogenic model in vitro [94] and a xenogeneic model in vivo [95].…”

Xenotransplantation literature update, July/August 2019

“…6 The incorporation of human amniotic epithelial cells to grafts preserved function and slowed rejection in comparison with unmodified islets. 6 In a separate study, after previously measuring serum levels of…”

“…Survivability and maintenance of glucose homeostasis following islet xenotransplant is dependent on weight and functional integrity of the xenotransplanted beta (β) cells . Zafar et al address this in their study on incorporating human amniotic epithelial stem cells that secrete beta cell trophic and immunomodulatory factors with porcine islet grafts. Porcine islets were isolated, maintained, assembled into grafts, and xenotransplanted in a porcine to murine model .…”

“…In the previous issue of Xenotransplantation, Zhou et al provided an updated review of the complement system in xenograft rejection; Hundrieser et al discuss how porcine and human MHC‐II polymorphisms influence donor reactivity; Ladowski et al seek to eliminate all donor xenoantigens; Cooper et al review a 9 gene alteration of porcine donors for clinical xenotransplantation; Zhou et al present a strategy to monitor xenograft rejection with porcine cDNA biomarkers; Zafar et al provide further research into reducing porcine islet immunoreactivity; Li et al studied the cold storage of porcine hepatocyte spheroids; Iizuka et al deep dive into porcine C‐peptide pharmacokinetics; and, finally, Zheng et al, Zhao et al, and Yoon et al provide updates in corneal xenotransplantation.…”