Aniridia-related keratopathy : structural changes in naïve and transplanted corneal buttons

Background: To study structural changes in naive and surgically treated corneas of aniridia patients with advanced aniridia-related keratopathy (ARK). Methods and findings: Two naive corneal buttons from patients with advanced ARK submitted to penetrating keratoplasty for the first time, one corneal button from an ARK patient that had undergone a keratolimbal allograft (KLAL), two corneal buttons from ARK patients who had previously undergone centered or decentered transplantation and were now retransplanted and two adult healthy donor control corneas were processed for immunohistochemistry. Antibodies against extracellular matrix components in the stroma and in the epithelial basement membrane (collagen I and IV, collagen receptor alpha 11 integrin and laminin alpha 3 chain), markers of fibrosis, wound healing and vascularization (fibronectin, tenascin-C, vimentin, alpha-SMA and caveolin-1), cell division (Ki-67) and macrophages (CD68) were used. Naive ARK, KLAL ARK corneas and transplanted corneal buttons presented similar histopathological changes with irregular epithelium and disruption or absence of epithelial basal membrane. There was a loss of the orderly pattern of collagen lamellae and absence of collagen I in all ARK corneas. Vascularization was revealed by the presence of caveolin-1 and collagen IV in the pannus of all ARK aniridia corneas. The changes observed in decentered and centered transplants were analogous. Conclusions: Given the similar pathological features of all cases, conditions inherent to the host seem to play an important role on the pathophysiology of the ARK in the long run