Effects of prostaglandin analogs and prostamides on expressions of CD31, CD54 and IL–8 by conjunctival cells in vitro

Abstract

Abstract: : Purpose: Prostaglandin analogs and prostamides have shown their efficacy for treating glaucoma patients but they may induce conjunctival hyperemia, suggesting proinflammatory properties, and contain various concentrations of benzalkonium chloride (BAC), a preservative widely known to induce toxic effects for the ocular surface. We therefore investigated their potential proinflammatory effects in a human conjunctiva–derived cell line by analysing the expression of molecules involved in the recruitment of inflammatory cells, the adhesion molecules CD31 and CD54 and the chemokine IL–8. Methods: Commercial preparations of latanoprost, travoprost and bimatoprost were investigated in Chang’s cell line, for 24, 48 and 72 hours, at a 1/100 dilution. Cells were also stimulated with 10^–6M PGF2α , 10 ng/ml TNFα, 10^–4% or 10^–3%BAC for the same durations. Membrane expression of CD31 and CD54 and intracytoplasmic IL–8 (IL–8c) were determined using flow cytometry, and IL–8 concentration in the supernatants was assessed by ELISA (IL–8s). Results: The expressions of CD54 and CD31, and the concentration of IL–8s were increased upon TNFα, whereas BAC and preparations of preserved prostaglandin analogs and prostamides decreased CD54 and CD31 proportionally to their BAC concentration. They had no effect on IL–8 expression. BAC significantly decreased cell density as well as total IL–8s, despite increasing intracytoplasmic concentrations within the remaining living cells. PGF2α did not stimulate any marker tested. Conclusions: This study thus demonstrates the absence of proinflammatory effects of prostaglandin analogs or prostamides in this conjunctiva–derived cell line, as assessed with major markers related to cell adhesion or chemotaxis. We also confirm the cytotoxic effects of BAC that has widely been suggested to participate in ocular inflammation in long–term treated glaucomatous patients.

Keywords: conjunctiva • cytokines/chemokines • drug toxicity/drug effects