Abstract
Purpose: :
The mechanism by which eosinophils adhere to the ocular surface during allergic inflammation is unknown. This study examined the effect of the anti–allergic drug olopatadine on eosinophil adhesion to human conjunctival epithelial cells following stimulation with tears collected from seasonal allergic subjects in season.
Methods: :
Allergic subjects (N=6) were treated in season for one week with olopatadine in one eye, while the other eye remained untreated. Tears were collected from both eyes using a micro–capillary tube. Human conjunctival epithelial cells were acquired by enzymatic digestion of cadaveric conjunctival tissues. Confluent cultures of human conjunctival epithelial cells were pre–incubated with tears (diluted 1:25 in media) for 24 hours. Eosinophils were purified from peripheral blood using negative magnetic bead selection. Eosinophil adhesion to conjunctival epithelial cells was measured using an assay for eosinophil peroxidase.
Results: :
Olopatadine treatment significantly inhibited the ability of tears to promote eosinophil adhesion resulting in a net decrease of 486.84 ±116.45 eosinophils/cm2 compared to tear–stimulated adhesion from untreated eyes (p<0.01). Mean percent inhibition was 43.3 ± 13.9%.
Conclusions: :
Olopatadine treatment inhibits the pro–inflammatory effect of allergic tears on eosinophil adhesion to human conjunctival epithelial cells in vitro. If similar effects occur in vivo, the efficacy of olopatadine in ocular allergic inflammation may be due, in part, to decreasing the number of eosinophils maintained on the ocular surface.
Keywords: conjunctivitis • inflammation