en
Doctoral thesis
English

Bioengineering of Prevascularized Endocrine Constructs for the Treatment of Type 1 Diabetes

Imprimatur date2024
Defense date2024
Abstract

Islet cell transplantation is a minimally invasive procedure that forms an integral part of the standard care for patients with complicated Type 1 Diabetes. Nonetheless, it is evident that the outcomes of islet transplantation, particularly in the long term, are far from optimal. Most patients require the transplantation of a substantial islet cell mass, which poses a significant problem due to the shortage of organs. The difficulty in achieving long-term function arises from several challenges that islets face during the islet isolation procedure and at the implantation site. These challenges include: (1) disruption of islet extra-cellular matrix (ECM), vasculature and innervation during the isolation process resulting in islet cell death both in the culture period and the early phases of the engraftment; (2) lack of prompt revascularization; (3) pro-inflammatory nature of the liver microenvironment; (4) immune attacks, including allo-rejection and auto-immunity recurrence. Thus, it is imperative to address the limitations of intraportal islet transplantation and identify alternative extra-hepatic transplantation sites.

This thesis seeks to advance the field by developing a functional prevascularized insulin-secreting construct toimprove islet engraftment, vascularization, survival and function while exploring alternative extra-hepatic transplantation sites such as epididymal fat pad -which is an environment similar to human omentum- and the subcutaneous space. To do so, several key strategies were developed: (1) Organoids generation with the formation of functional and uniformly sized insulin-secreting organoids; (2) Incorporation of human amniotic epithelial cells (AECs) as supporting cells due to their cytoprotective, low antigenicity, anti-fibrotic, anti-inflammatory and immunomodulatory properties; (3) Incorporation of blood outgrowth endothelial cells (BOECs) as a potential autologous endothelial cell source to improve graft revascularization; (4) Incorporation of insulin-secreting organoids into a bioengineered human amniotic membrane (hAM)-derived hydrogel scaffold, to provide an optimal microenvironment and structural support for the insulin-secreting cells.

The thesis adopts an article-based format and is composed of 2 main sections. The first section includes a chapter published in Type-1 Diabetes. Methods in Molecular Biology, which describes the protocol for generating insulin-secreting organoids and their in vitro assessment. The second section constitutes a manuscript, containing the results and discussion of the experiments of the main project conducted throughout my thesis. Altogether, our findings demonstrate that incorporating prevascularized organdies (PVOs), enriched with AECs and BOECs as supporting cells, in a BOEC-vascularized hAM-derived hydrogel, significantly improved engraftment and revascularization, leading to prompt diabetes reversal. Our strategy shows potential to pave the way for the engineering of a bioartificial pancreas.

eng
Keywords
  • Human amniotic epithelial cells
  • Organoids
  • Blood outgrowth endothelial cells
  • Human amniotic membrane
  • Type 1 Diabetes
  • Islet cell transplantation
  • Islets
  • Extra-cellular matrix
Citation (ISO format)
OLIVEIRA ALMEIDA FONSECA, Laura Do Mar. Bioengineering of Prevascularized Endocrine Constructs for the Treatment of Type 1 Diabetes. 2024. doi: 10.13097/archive-ouverte/unige:176501
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Thesis
accessLevelPrivateaccessLevelPublic 01/01/2028
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Technical informations

Creation03/31/2024 12:10:51 PM
First validation04/18/2024 9:30:50 AM
Update time04/18/2024 9:30:50 AM
Status update04/18/2024 9:30:50 AM
Last indexation05/06/2024 6:25:00 PM
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