Regenerative medicine applications in paediatric urology : barriers and solutions

Radford, Anna Rebecca

Medicine
July 2015

Thesis or dissertation


Rights
© 2015 Anna Rebecca Radford. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Abstract

Tissue engineering and regenerative medicine offers opportunities to introduce new techniques into paediatric urology practice.

In this thesis, two experimental approaches were used. The initial approach considered improvements to the concept of composite cystoplasty; where high pressure in end-stage disease bladders is alleviated by augmentation using bowel smooth muscle lined by an autologous in vitro-grown bladder epithelium. Secondly, a porcine bladder acellular matrix (PABM) was tested as a free graft in a surgical model as proof of principle for its use in hypospadias repair.

Immunohistochemical characterisation of neuropathic bladders was performed. A disease-model was created in order to mimic the disease phenotype using propagated normal urothelial cells and tissue in vitro. Trans-epithelial electrical resistance was used to measure barrier function in differentiated urothelium. Immunocytochemistry, immunoblotting and RTPCR was utilised to identify any mechanistic pathways leading to heritable changes in phenotype.

Assessment of human neuropathic bladder biopsies demonstrated significant labelling of a hypoxia-related transcription factor. In vitro hypoxia significantly reduced the proliferation and differentiation capacity of urothelial cells. The proliferative capacity recovered upon switching to normoxia, however, the differentiation-associated compromise persisted. Repressive epigenetic marks were found to alter location and abundance in the compromised urothelium. These marks were targeted using an epigenetic-modifying agent, which significantly recovered the differentiated urothelial phenotype. Importantly this was replicated in urothelium from diseased bladders.

Integration of the PABM was superior to Pelvicol™. A subpopulation of CD45⁻ CD163⁺ cells was identified, which were believed to be important in biomaterial remodelling.

It is proposed that hypoxia results in persistent heritable compromise in differentiated urothelium. The urothelial phenotype is recoverable by the application of an epigenetic modifying agent. By using an integrated approach both the epigenetic–modifying agent and PABM may provide strategies to improve the efficacy of autologous tissue engineering approaches in paediatric and adult urology.

Publisher
Hull York Medical School, The University of Hull and the University of York
Supervisor
Southgate, Jennifer; Subramaniam, Ramnath
Sponsor (Organisation)
European Society for Pediatric Urology
Qualification level
Doctoral
Qualification name
PhD
Language
English
Extent
4 MB
Identifier
hull:13127
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