Omega–3 Polyunsatulated Fatty Acids (PUFA) Suppress Chemokine Production In Cultured Human Conjunctival Fibroblasts

Abstract

Purpose: : Omega–3 polyunsaturated fatty acids (PUFA), such as docosahexaen acid (DHA) and eicosapentaen acid (EPA), have been found to suppress inflammatory diseases as well as cardiovascular diseases. To study the suppressive effects of omega–3 PUFA on ocular allergic inflammation, we measured omega–3 PUFA in serum, and investigated chemokine production in conjunctival fibroblasts cultured with omega–3 PUFA.

Methods: : Omega–3 PUFA concentrations in the peripheral blood of 15 atopic keratoconjunctivitis (AKC) patients, 13 seasonal allergic conjunctivitis (SAC) patients and 10 non–allergic volunteers were measured by high performance gas chromatography. Human conjunctival fibroblasts were cultured with DHA (100micro–g/ml) for 24 hrs, and consequently stimulated with TNF–alpha (30ng/ml) and IL–4 (30 ng/ml). Eotaxin, RANTES and ICAM–1 mRNA expressions in cultured cells were investigated by using realtime–PCR (n=3). Eotaxin and RANTES production in culture supernatants were measured by ELISA (n=3).

Results: : The amount of Omega–3 PUFA in serum is usually indicated by the ratio of EPA against arachidoic acid (AA), such as EPA/AA ratio. EPA/AA ratio of AKC patients (0.16±0.22) was significantly less than that of SAC patients (0.45±0.34) and non–allergic volunteers (0.38±0.45) (p<0.05). Pre–incubation with DHA increased omega–3 PUFA in cultured fibroblasts by 2–3 folds. Eotaxin, RANTES and ICAM–1 expression in fibroblasts were suppressed by DHA pre–incubation (59%, 64% and 43% suppression). Eotaxin and RANTES productions were also suppressed by DHA pre–incubation (42% and 38% suppression).

Conclusions: : Omega–3 PUFA was decreased in ocular allergic patients. The regulatory effect of omega–3 PUFA chemokine production from conjunctival fibroblasts may be a factor that affects the severity of allergic disease.

Keywords: cytokines/chemokines • conjunctivitis • inflammation