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B. Maguen, E. Maguen, A.V. Ljubimov; Immunohistochemical Evaluation of Two Corneal Buttons With Post LASIK Keratectasia . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4373.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To perform an immunohistochemical evaluation of two corneal buttons diagnosed with post LASIK keratectasia, obtained following corneal transplantation. Methods: Two ectatic corneas after penetrating keratoplasty were embedded in OCT within 3 hours after surgery and cryostat sections analyzed by immunofluorescence with antibodies to 29 extracellular matrix (ECM) components and proteinases. Results: The ratio of distance between the LASIK flap interface and the upper epithelial layer to the total corneal thickness was 0.2 in the first case and 0.32 in the second. The interface was highlighted only with an antibody to fibronectin. Other stromal ECM components (types VI and XIV collagen, fibrillin–1, tenascin–C, and vitronectin) were unchanged with no evidence of fibrosis. In the epithelial basement membrane (EBM) type IV collagen α5 chain, nidogen–2, chains of laminin–8 and laminin–10 showed weak and discontinuous staining. Type IV collagen α1/α2 chains were found in the EBM but were absent there in control healthy corneas. These changes were similar to those observed in bullous keratopathy and keratoconus corneas. Other EBM components did not show visible changes. Of five matrix metalloproteinases (MMP) studied, MMP–10 showed increase in the epithelium and MMP–3, in some stromal keratocytes compared to control healthy corneas. MMP–3–positive keratocytes were usually found in the vicinity of flap interface. Patterns of urokinase and cathepsins F, H, and L were similar to normal. A limbal basal epithelial marker, α–enolase, was absent in the first case and only showed scattered positive cells in the second, attesting to essentially normal epithelial differentiation. Conclusions: Abnormal EBM structure similar to that found in keratoconus and bullous keratopathy along with an increase in certain MMPs were found suggesting an ongoing lysis and remodeling of basement membrane. Further studies are needed to finally confirm these findings.
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