PURPOSE:The limbus of the cornea is said to be the niche for limbal stem cells (LSCs) and the primary source of corneal epithelial maintenance. In this model, adult corneal epithelial cells are maintained by LSCs that cycle slowly and give rise to transient amplifying (TA) cells. These migrate centripetally, differentiate outwards to the surface, and are then lost by desquamation. This study set out to investigate the stem cell properties of human corneal epithelium and their contribution towards corneal epithelial regeneration after wounding. METHODS: Frozen sections of human corneal tissues were labelled with a number of putative stem cell markers. Human central and limbal corneal epithelial cells were isolated for holoclone formation assay and FACS isolation. Side population (SP) cells were separated based upon cell size and Hoechst dye efflux ability. A human corneal organotypic culture model was used to assess corneal healing in vitro. Injured corneas were analysed using cytokine antibody arrays and immunohistochemical markers for cell proliferation and stem cells. RESULTS: The expression of putative stem cell markers ΔNp63α and ABCG2 was clearly evident in the suprabasal and basal layers of the limbus, but was also observed in central epithelium. Human limbal and central corneal epithelial cells were both capable of forming holoclones in 2:1 ratio respectively. In FACS, central SP and limbal SP cells showed no significant difference based upon size and dye efflux. After wounding, the capacity for epithelial cell proliferation and migration appears to be as active in the central cornea as in the periphery/limbus. Central and peripheral epithelial recovery remains equal even after ablation of the limbus. CONCLUSION: Cells from the central human corneal epithelium have many putative stem cell properties. These results raise questions not only about the distribution and substance of stem cells in the cornea, but also the role of the limbus itself. The central epithelium is able to heal independently of the limbus.
| Identifer | oai:union.ndltd.org:AUCKLAND/oai:researchspace.auckland.ac.nz:2292/4954 |
| Date | January 2009 |
| Creators | Chang, Chuan-Yuan Ally |
| Contributors | Green, Colin, Sherwin, Trevor |
| Publisher | ResearchSpace@Auckland |
| Source Sets | University of Auckland |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated., https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm, Copyright: The author |
| Relation | PhD Thesis - University of Auckland, UoA1914009 |
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