PGE2 production from conjunctival and corneal cells in allergic conditions and the measurement of PGE2 concentrations in tears of patients with severe ocular allergies.

Abstract

Abstract: : Purpose:Prostaglandin–E2 (PGE2) has been reported to potentiate degranulation of mast cells stimulated with IgE and Ag. To examine the role of PGE2 in ocular allergies, we examined the production of PGE2 by corneal and conjunctival cells and also measured its concentration in tears of patients with severe ocular allergies. Methods:PGE2 was measured in tears from patients with severe ocular allergies complicated by corneal lesions and patients with post–surgical(PKP) inflammation. Primary cultures of human corneal epithelium and keratocytes, and conjunctival epithelium and fibroblasts were incubated with IL–4 and TNF–α. The culture supernatants were removed after exposure and concentrations of PGE2 were quantified by ELISA assay. Cyclooxygenase–2 protein expression was analyzed by Western blot. Results:Significantly higher tear levels of PGE2 were observed in patients with allergic inflammation than in those in postsurgical inflammation. Stimulation with IL–4 and TNF–αkinetically induced the generation of PGE2 in keratocytes and conjunctival epithelial cells and fibroblasts with expression of cyclooxygenase–2, but induced little production in corneal epithelial cells. This production was down–regulated by aspirin, but not by cyclosporine A or FK–506. Conclusions:PGE2 was produced by keratocytes, conjunctival epithelial cells and fibroblasts. Such cells may release PGE2 into the tears of allergic patients leading to the propagation of allergic inflammation.

Keywords: cornea: tears/tear film/dry eye • conjunctiva • cornea: basic science