Persistent adhesion of corneal epithelial tissue on synthetic lenticules in vivo

Purpose: In intact cornea, firm anchorage of-the epithelium to its underlying stroma is provided by a system of adhesive structures, which include the epithelial basement membrane, adhesion complexes and associated alpha 6 beta 4 integrin receptors. In the present study we sought to determine whether the sustained epithelialization of synthetic lenticules observed in vivo involved the formation of adhesive structures at the epithelial-lenticule interface similar to those present in intact tissue. Methods: Collagen I-coated microporous polycarbonate membranes were implanted in the anterior stroma of adult cats. Successfully epithelialized lenticules were maintained on eye for 9-12 weeks, after which time the epithelial-lenticule interface was examined for evidence of adhesive structures using immunohistochemistry and electron microscopy. Results: Immunohistochemistry identified laminin, hemidesmosomal plaque, collagen VII and alpha 6 integrin at the tissue-lenticule interface. Ultrastructural examination showed evidence of assembly of-these components into a basement membrane and adhesion complexes. Conclusions: The formation of these adhesive structures is likely to have, contributed to the sustained epithelialization observed clinically on the collagen-coated synthetic lenticules.