Topical aminocaproic acid facilitates reepithelialization of persistent epithelial defects

Purpose. After corneal injury, persistent epithelial defects (PED's) may oc cur due to the chronic failure of the regenerating epithelium to adhere to the underlying stroma. The aim of this study was to examine the potential o f epsilon-aminocaproic acid (EACA) as a topical treatment for PED's. EACA i nhibits the activation of plasmin, which metabolizes fibronectin. Fibronect in, a glycoprotein, anchors corneal epithelium to the basement membrane and the underlying stroma. Methods. In anesthetized rabbits, PED's were induced with sodium hydroxide (1 N). Seven days later, during the late healing phase, treatment began wit h administration of EACA (30%) to the right eye and administration of vehic le alone to the left eye three times daily. A control group received neithe r EACA nor vehicle. Rabbits were treated for 19 days. PED's were visualized by fluorescein staining. Their size was mapped using digital planimetry. Results. After 11 days of treatment with EACA, treated PED's were 50% small er than in corneas treated with vehicle alone. Following treatment for 15 d ays, corneas treated with EACA had significantly greater re-epithelializati on than vehicle-treated or control corneas. Frozen sections stained immunof luorescently for fibronectin appeared to qualitatively contain more adheren t fibronectin in treated corneas. Transmission and scanning electron micros copy indicated that the epithelium was more polymorphic, thinner and vacuol ated in untreated controls compared to EACA treated eyes. Light microscopy demonstrated more continuous adherent epithelium after EACA treatment. Conclusions. Topically administered EACA decreases both the severity and in cidence of persistent epithelial defects produced by alkali burns to the co rnea. EACA appears to promote adherence of the regenerating epithelium to t he underlying stroma. Thus, topically administered EACA may be an effective treatment for this chronic condition.