PERSISTENT ADHESION OF CORNEAL EPITHELIAL TISSUE ON SYNTHETIC LENTICULES IN-VIVO

Purpose: In intact cornea, firm anchorage of-the epithelium to its und erlying stroma is provided by a system of adhesive structures, which i nclude the epithelial basement membrane, adhesion complexes and associ ated alpha 6 beta 4 integrin receptors. In the present study we sought to determine whether the sustained epithelialization of synthetic len ticules observed in vivo involved the formation of adhesive structures at the epithelial-lenticule interface similar to those present in int act tissue. Methods: Collagen I-coated microporous polycarbonate membr anes were implanted in the anterior stroma of adult cats. Successfully epithelialized lenticules were maintained on eye for 9-12 weeks, afte r which time the epithelial-lenticule interface was examined for evide nce of adhesive structures using immunohistochemistry and electron mic roscopy. Results: Immunohistochemistry identified laminin, hemidesmoso mal 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. Conc lusions: The formation of these adhesive structures is likely to have, contributed to the sustained epithelialization observed clinically on the collagen-coated synthetic lenticules.