Abstract
Purpose::
One of the most successful examples of regenerative medicine has been the use of cultured limbal epithelial cells (enriched in corneal epithelial stem cells) as the starting material for treating patients with limbal stem cell deficiency (LSCD). To date little information exists on the phenotype of the corneal epithelium generated following cultivated limbal epithelial transplantation (CLET).
Methods::
Twenty-nine patients undergoing penetrating keratoplasty (PK) for visual rehabilitation following CLET were included in the study. The regenerated corneal epithelium following autologus and allogenic CLET was evaluated by: light and transmission electron microscopy, immunostaining for the presence of a basement membrane; and expression of the K3 corneal epithelial keratin. For gene expression profiling, basal cells from the corneal buttons were isolated using laser capture microdissection. In some samples the entire epithelium was isolated after EDTA treatment. RNA was analyzed by cDNA microarrays for transcriptional profiling.
Results::
Twenty-nine eyes underwent PK at a mean interval of 5.7 (2- 9) months after CLET. An intact corneal epithelium was present in 28 of the 29 samples (96.5 %), with multilayering noted in 25 of the samples (86%). Basement membrane formation as assessed by collagen IV expression and the presence of a hemidesmosomal complex was observed in ~90% of the patients. K3 was expressed in all samples. Persistence ofamniotic membrane was noted in 5 cases. In-vivo survival and stratification of the corneal epithelium was confirmed in all cases (10) that were assessed by clinical confocal microscopy. Transcriptional profiling is in progress.
Conclusions::
Use of ex vivo expansion of the limbal epithelial cells for the treatment of LSCD, results in the generation of an epithelium that, for the most part, mimics the corneal epithelium for an extended period of time (~6 months). This therapeutic modality is promising for the long-term management of LSCD.
Keywords: cell survival • cornea: epithelium • gene microarray