816-P: Bioprinted Allogeneic Islet–Containing Implants Normalize Blood Glucose Control in Diabetic Rat Models without Immune Suppression

Transplantation of cadaveric islets can reverse type 1 diabetes (T1D) but requires life long immunosuppression. Cell encapsulation has potential to overcome this challenge by blocking immune cell access to islet grafts while allowing nutrient exchange, glucose sensing and insulin release. In this study, 3D tissues consisting of patterned, multi-shell fibres with an islet-containing core and immunoprotective shell were manufactured using Aspect Biosystems’ microfluidic 3D bioprinting technology for implantation in diabetic rats. Blood glucose and animal body weight were monitored for several months following surgery. Upon retrieval, bioprinted tissues were assayed for islet cell viability and function by glucose-stimulated insulin secretion (GSIS) , followed by histology and immunohistochemistry (IHC) to analyze foreign body response (FBR) and immune cell infiltration. 3D bioprinted implants containing reaggregated allogeneic rat islets re-established normoglycemia for > 90 days in streptozotocin-treated diabetic immunodeficient rats, and > 30 days in diabetic immunocompetent rats. Post-retrieval, tissue implants demonstrate high viability and functionality, with absence of immune cell penetration through the shell, confirming its immune protective properties. Modification of the outer shell biomaterial to reduce FBR was shown to extend islet tissue implant functionality. This is the first study describing a 3D bioprinted implant composed of a core/shell micro-fibre used to deliver therapeutic islets into diabetic animals. The promising results obtained in rodent models open the door to further testing in larger animal models and, eventually, T1D patients. Disclosure V.Russo: None. S.Getsios: None. T.J.Kieffer: Consultant; Fractyl Health, Inc., Sigilon Therapeutics, Inc., Employee; ViaCyte, Inc., Research Support; Aspect Biosystems. S.Wadsworth: None. R.Jalili: None. Y.Yu: None. R.Agarwal: None. S.Pan: None. N.Hakimi: None. K.Jahan: None. E.M.Wilts: None. S.Ida: None. Funding National Research Council Canada - Industrial Research Assistance Program (#935249) , Canadian International Innovation Program (#938664) , Genome British Columbia (#GEN009) , Stem Cell Network (#FY20/FBP-7 Kieffer) , Mitacs (#IT19764) ,