Séance

52 - Communication libre
Transplantation and regeneration
3 juin 2021, 13:50 - 15:20, Stream 4: Video Invited, SST, SSCViscérale & ARS

Abstract

6
Pre-vascularized organoid from decellularized human placenta support pancreatic tissue in type 1 diabetes treatment.
K. Bellofatto, C.-H. Wassmer, F. Lebreton, L. Perez, R. Hanna, M. Hasany, R. Khatri, L. Mar Fonseca, A. Peloso, D. Bosco, C. Toso, T. Berney, E. Berishvili, Presenter: K. Bellofatto (Geneva)

Objective
Replacing damaged organs with biological substitutes capable of protecting the islets and facilitating vascularization is a great objective in regenerative medicine, in particular in the field of islet transplantation. A decellularized placenta includes a large number of recellularizable cotyledons with a conserved vessel structure of the native organ. Our goal is to obtain a decellularization protocol to generate pre-vascularized organoids by recellularizing this ECM with HUVECs and pancreatic islets.
Methods
Placentas were cannulated through the chord veins and arteries to to remove blood, followed by dissection of selected cotyledons.Decellularization was performed using a bioreactor. Proper cell removal was assessed by histology and quantification of residual DNA. Presence of structural proteins was analyzed, as well as the ECM structure using SEM, CT scan and mass spectrometry. Recellularization protocols were conducted, using HUVECs or BOECs as endothelial cell sources, combined with Ins-1E cells or rat islets (injected in the HUVECs-recellularized vessels) as insulin secreting cell sources. Function of recellularized cotyledons was assessed in vitro with glucose stimulated insulin secretion tests (GSIS). To assess in vivo biocompatibility and function of the scaffolds, we transplanted in Sterptozotocin-induced diabetic NSG mice first only the decellularized cotyledons, to study degradation and/or integration, and then with the recellularized cotyledon. Glycaemia was measured every day to monitor normalization of blood glucose levels.
Results
We achieved successful decellularization of the cotyledons, as evidenced by the absence of cells and the preserved ECM structure on histological stainings. No residual DNA was found in the samples. Quantification of GAG and hydroxyproline as well as the mass spectrometry analysis shows that structural proteins are conserved. SEM and CT scan images revealed that the cotyledon ECM structure was preserved after the decellularization protocol. Cells after recellularization were functional showing a good vascularization after 7 days. The GSIS shows a perfect organ response in the production of insulin when stimulated with 16.7mmol of glucose.
Conclusion
The decellularized cotyledon is the perfect scaffold to reproduce a prevascularized and insulin-producing organ, which allows transplanted cells to survive during the peri-transplantation period.
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