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Title: Strategies for tissue engineered airway epithelialisation for fetal and paediatric patients
Author: Maughan, Elizabeth
ISNI:       0000 0004 8499 9439
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2019
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Tissue engineering has already shown potential in yielding rationally-designed constructs capable of tracheal replacement, but a successful strategy for reliably epithelializing these grafts has not yet been well-established. A rabbit in vivo interventional model was validated for the orthotopic transplantation of paediatric tissue-engineered airway constructs, and used to longitudinally test non-cell seeded tracheal scaffolds from materials used in three clinically-applied strategies. Tracheal autografts had excellent clinical, bronchoscopic and histological outcomes, but no scaffold option tested could deliver a stable non-stenosing airway after four weeks. This model is now ready to test approaches to encourage epithelial cell engraftment. As a potential prenatally-accessible cell source for airway epithelial regeneration, primary human amniotic fluid cells were isolated, cultured and evaluated in vitro using flow cytometry, immunofluorescence, differentiation assays and qPCR. It was not possible to identify cells of specific respiratory potential and the shortage of suitable samples became an obstacle to verifying these findings. Next, native airway epithelium was evaluated as a postnatal source of autologous cells. The phenotypic and genotypic differences were studied between fresh airway epithelium and cultured primary bronchoepithelial cells (BECs) from paediatric and non-smoker adult tracheae in terms of stem cell abundance, gene expression, proliferation and differentiation potential. Absolute proportions of basal cells were similar between adults and children, but paediatric BECs displayed higher clonal potential and outcompeted adult BECs in head-to-head competition assays. RNA sequencing showed adult airway epithelial gene expression patterns suggestive of increased oxidative stress, with some Notch and canonical Wnt pathway upregulation suggesting that adult airway epithelium might have a more secretory phenotype. Increased adult expression of secretory markers persisted in basal cell cultures and in differentiation assays. Exploring the functional relevance of these findings could provide insight into how epithelialisation of tissue-engineered tracheal grafts might be improved for both paediatric and adult patients.
Supervisor: De Coppi, P. ; Janes, S. ; Birchall, M. ; Gomez Lopez, S. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available