Transplantation of ex-vivo cultured limbal epithelial cells (LEC) is an established treatment for total limbal stem cell deficiency. However, this therapy has preceded the scientific understanding of limbal epithelial stem cells (LESC), the LESC niche and the biological mechanism that underpins it. This body of work tested the hypothesis that the LESC niche has a specialised structure and that an understanding of this may lead to improvements in outcomes and understanding of this therapy. The corneal limbus was investigated using 3D confocal microscopy, scanning electron microscopy, wholemount immunofluorescence and in-vivo confocal microscopy. This produced the most comprehensive study of limbal architecture performed to date. The structure of the LESC niche was identified and the effect of age and disease examined. Next, a clinical study of ex-vivo expansion and transplantation of LEC was performed in patients with LESC deficiency. A defined set of objective outcome measures enabled a baseline standard for outcomes of this therapy to be described. Future improvements to this therapy can be assessed using these techniques. Human amniotic membrane (HAM) is the leading candidate for a surrogate LESC niche. The method of HAM processing was investigated and found to be critical to achieve this. A method of significantly improving the yield of LESC in culture on HAM was identified. It remains to be seen whether this will translate into improved clinical outcomes. Finally, a disconnection exists between published data indicating a good clinical outcome and data demonstrating the survival of transplanted cells. This work assessed and demonstrated the feasibility of using quantum dot nanocrystal labelling of transplanted LESC to track cells post transplantation. It is concluded that translation of these findings to modify and improve current treatment protocols may result in improvements in outcomes for patients with LESC deficiency undergoing this therapy.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:625247 |
| Date | January 2009 |
| Creators | Shortt, A. J. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/18929/ |
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