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Jena Chojnowski, Jiha Kim, Phillip A Moore, James D Lauderdale; Bioengineering corneal tissue for the treatment of aniridic-related keratopathy. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2074.
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© ARVO (1962-2015); The Authors (2016-present)
When limbal stem cells (LSCs) are damaged or dysfunctional, a disease state termed limbal stem cell deficiency (LSCD) develops, which is characterized by impaired corneal wound healing and loss of corneal integrity. These defects are typically treated by transplantation of donor limbal tissue; however, this treatment has significant limitations in the treatment of aniridic patients whose eye cells are physiologically different than those of a normal individual and often respond uniquely to surgical treatment. Aniridia is caused by PAX6 heterozygous null mutations with Anirida-related keratopathy (ARK) due to LSCD being a leading cause of vision loss in aniridics. This study’s goal is to develop a cell-based approach capable of preserving a clear cornea for a person with Aniridia. This study’s purpose is to understand the molecular changes in LSCs associated with LSCD and to determine if cultured LSCs with a functional copy of PAX6 can be transplanted into an animal model and contribute to the maintenance of the cornea.
We cultured limbal explants from normal and aniridic LSCs and immunostained for markers specific to the different cell types present in the LSC region like ABCG2 (progenitor), cytokeratin 12 (transient amplifying cell), and E-cadherin (corneal basal cell). In concert, we studied these same characteristics in the mouse model system for Aniridia. Also, we transplanted cultured normal human LSCs with or without a PAX6 BAC expression transgene into six New Zealand white rabbits. Rabbits exhibit LSCD due to a limbalectomy performed on the right eye of each rabbit. An ophthalmic examination after the transplant was performed every other day until day 7, then twice a week until fully healed. Rabbits were euthanized 45 days post operation and immunohistological staining for different cell types was performed.
We were able to characterize the different cell types within the LSC region from the donor tissue of normal and PAX6 deficient humans, as well as in the mouse model system for Aniridia. In addition, the normal human LSCs harboring the PAX6 BAC expression transgene did functionally reconstruct the corneal epithelium in our rabbit model for LSCD.
Ultimately, these studies lead to our proposition that culturing aniridic LSCs ex vivo, introducing a PAX6 BAC expression transgene, and then transplanting those cells back into the patient’s eyes will successfully treat ARK.
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