University of Geneva
Bioengineered insulin-secreting 3D constructs
Mohamed Alibashe Ahmed1, Géraldine Parnaud1, Vanessa Lavallard1, Domenico Bosco1, Thierry Berney1, Ekaterine Berishvili1,2.
1Cell Isolation and Transplantation Center, Department of Surgery , Geneva University Hospitals and University of Geneva, Geneva, Switzerland; 2Center of Molecular and Translational Medicine, Institute of Medical Research, Ilia State University, Tbilisi, Georgia
Background: Pancreatic islet transplantation is an emerging physiologic alternative to insulin therapy. Islet engraftment and survival is currently impaired by several factors including disruption of cell–matrix relationship, inflammation at the site of implantation, hypoxia before graft revascularization, toxicity of immunosuppression and recurrence of autoimmunity and/or allograft rejection. Strategies using appropriate combinations of cells, scaffolds and biologically active compounds may enhance islet engraftment and survival.
Methods: In this study we have generated 3D constructs composed of islets, amniotic epithelial cells (AECs) and human amniotic membrane matrix (HAM). Composite AEC/islet constructs were formed by suspension co-culture and seeded on HAM. The 3 D constructs were assessed for viability and functional integrity. Mixed lymphocyte–islet reactions (MLIR) was utilized to analyze the effect of AECs on the innate and adaptive immune reactions triggered by the islets. To test in vivo biocompatibility, empty and islet/AEC seeded HAM matrices were implanted into Lewis rats in omental pouches.
Results: AECs rapidly adhered to islets and spread out to cover the islet surface. Insulin and glucagon expression and Live/Dead staining showed that viability and function of AEC/islet constructs cultured on HAM matrix was significantly higher than that of islets in free-floating culture. In addition, significant enhancement of glucose-stimulated insulin secretion was observed from AEC/islets cultured on amniotic membranes as compared to islets cultured free-floating. Moreover, AECs suppressed lymphocyte proliferation induced by islet cells in MLIR. Two weeks following implantation, H&E staining of retrieved grafts showed that most transplanted islets were distributed throughout the matrices and exhibited high expression of insulin and glucagon.
Conclusion: These data indicate that bioengineering of insulin-secreting 3D constructs may improve the success rate of clinical islet transplantation by providing tissue specific extracellular matrix and permanent localized immune-protection to the transplanted islets.