Indexed on: 28 Apr '09Published on: 28 Apr '09Published in: Ophthalmology
Transplantation of in vitro-cultivated limbal epithelium (TCLE) recently was developed to treat limbal stem cell deficiency (LSCD). The objective of this study was to characterize changes in the cornea during LSCD and on the corneal surface after TCLE.Experimental study.The pannus tissue excised from the corneas of 17 LSCD patients was analyzed to characterize the changes in the cornea during LSCD. Five corneal buttons obtained during perforating keratoplasty (pKP) from patients who had undergone TCLE at least 6 months before pKP were examined to assess the effect of TCLE. Six samples of healthy central cornea and 6 of bulbar conjunctiva served as control tissue.The expression of epithelial lineage markers (keratin [K] 3, K12, K19, and mucin 5AC) and inflammatory markers (interleukin-1alpha [IL-1alpha], IL-1beta, intercellular adhesion molecule 1 [ICAM-1], vascular cell adhesion molecule 1 [VCAM-1], and vascular endothelial growth factor [VEGF]) were analyzed using real-time polymerase chain reaction, Western blotting, and immunofluorescence in the tissue samples.Comparison of the markers' expression patterns.The expression of all markers differed in healthy cornea and conjunctiva. Expression of lineage markers was similar in pannus to conjunctiva, but not to cornea. Interleukin-1beta, ICAM-1, VCAM-1, and VEGF were increased significantly in pannus compared with the levels in healthy cornea. Interleukin-1alpha, IL-1beta, and ICAM-1 were increased compared with healthy conjunctiva. The TCLE improved vision and reduced inflammation, vascularization, and discomfort. After TCLE, the lineage markers in the excised corneal buttons showed a corneal phenotype and a significant reduction in inflammatory markers in 4 of 5 cases.Limbal stem cell deficiency is characterized by ingrowth of abnormal inflamed tissue with a conjunctival phenotype. Transplantation of limbal epithelium cultivated in vitro on intact amniotic membrane restored a noninflamed ocular surface and a corneal phenotype.The author(s) have no proprietary or commercial interest in any materials discussed in this article.