title: Olopatadine inhibits anti-immunoglobulin E-stimulated conjunctival mast cell upregulation of ICAM-1 expression on conjunctival epithelial cells.
abstract: BACKGROUND
  Olopatadine is a clinically effective dual-action (antihistamine/mast cell stabilizer) ophthalmic antiallergic agent. We have previously demonstrated that olopatadine inhibits tumor necrosis factor alpha (TNF-alpha) release from purified human conjunctival mast cells and that supernates from stimulated mast cells upregulate intercellular adhesion molecule 1 (ICAM-1) expression on epithelial cells via TNF-alpha.
  
  
  OBJECTIVE
  To investigate the effect of olopatadine on the TNF-alpha-mediated mast cell upregulation of ICAM-1 expression on conjunctival epithelial cells.
  
  
  METHODS
  Human conjunctival mast cells and epithelial cells were purified (>95%) from cadaveric tissue. Conjunctival mast cells were preincubated with three doses (30, 300, or 3,000 microM) of olopatadine or buffer alone for 30 minutes followed by 90-minute challenge with anti-immunoglobulin E (10 microg/mL). The resulting supernates were incubated with conjunctival epithelial cell monolayers for 24 hours along with the following treatments: rTNF-alpha, mast cell supernate + anti-TNF-alpha, recombinant (r)TNF-alpha + anti-TNF-alpha, the three doses of olopatadine, olopatadine supernates, olopatadine supernates + rTNF-alpha. ICAM-1 expression was measured using flow cytometry.
  
  
  RESULTS
  Anti-IgE-stimulated human conjunctival mast cell supernates upregulated human conjunctival epithelial cell ICAM-1 expression to the same extent as rTNF-alpha. ICAM-1 upregulation could be completely blocked with anti-TNF-alpha. Preincubation of conjunctival mast cells with olopatadine significantly blocked the ability of supernates to upregulate ICAM-1 on conjunctival epithelial cells. ICAM-1 expression could be restored by adding rTNF-alpha to the olopatadine-preincubated mast cell supernates.
  
  
  CONCLUSIONS
  Olopatadine is able to significantly decrease the anti-immunoglobulin E mast cell supernate-mediated upregulation of ICAM-1 on human conjunctival epithelial cells in vitro. This seems to be mediated through an effect on a TNF-alpha-specific mechanism.
authors.affiliation: University of Wisconsin-Madison, School of Medicine, Department of Medicine, USA.
authors.forename: E B
authors.initials: EB
authors.lastname: Cook
authors.forename: J L
authors.initials: JL
authors.lastname: Stahl
authors.forename: N P
authors.initials: NP
authors.lastname: Barney
authors.forename: F M
authors.initials: FM
authors.lastname: Graziano
mesh_terms: D018926:Anti-Allergic Agents / Q000494:pharmacology*; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D002478:Cells, Cultured; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D003233:Conjunctivitis, Allergic / Q000276:immunology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003990:Dibenzoxepins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004336:Drug Antagonism; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis*; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology*; D000069605:Olopatadine Hydrochloride; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D018926:Anti-Allergic Agents; D000888:Antibodies, Anti-Idiotypic; D017077:Culture Media, Conditioned; D003990:Dibenzoxepins; D006634:Histamine H1 Antagonists; D014409:Tumor Necrosis Factor-alpha; C026408:anti-IgE antibodies; D018799:Intercellular Adhesion Molecule-1; D000069605:Olopatadine Hydrochloride