Patanol
Anti-allergic drug olopatadine suppresses murine contact hypersensitivity and downmodulates antigen-presenting ability of epidermal Langerhans cells.

Tokura Y, Kobayashi M, Ito T, Takahashi H, Matsubara A, Takigawa M.

Department of Dermatology, University of Occupational and Environmental Health, Kitakyushu, Japan. tokura med.uoeh-u.ac.jp

Olopatadine hydrochloride is an H1-receptor-blocker but has other anti-allergic pharmacological potencies. We investigated whether olopatadine inhibits murine contact hypersensitivity, focussing on its modulatory action on epidermal Langerhans cells serving as antigen-presenting cells. While BALB/c mice were sensitized and challenged epicutaneously with hapten, they were administered intraperitoneally with olopatadine. Olopatadine at 1 or 0.2 mg/kg of weight significantly suppressed the sensitivity when injected at least once before sensitization or challenge. In olopatadine-injected mice, the ability of Langerhans cells to present hapten to primed T cells was reduced with decreased expression of MHC class II and co-stimulatory molecules. Langerhans cells exposed in vitro to 10(-5) or 10(-6) M olopatadine had less antigen-presenting activity than control, whereas neither T cell proliferation nor keratinocyte production of IL-1alpha and IP-10 was affected at these doses. These findings suggest that olopatadine downmodulates contact hypersensitivity at least partly by interfering with the antigen-presenting ability of Langerhans cells.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14572800&dopt=Abstract olopatadine Patanol



Patanol
Interactions of olopatadine and selected antihistamines with model and natural membranes.

Brockman HL, Momsen MM, Knudtson JR, Miller ST, Graff G, Yanni JM.

The Hormel Institute, University of Minnesota, Austin, MN, USA

OBJECTIVE: Olopatadine, an effective topical ocular human conjunctival mast cell stabilizer/antihistaminic antiallergic drug, was evaluated and compared to selected classical antihistamines for their interaction with model and natural membranes to ascertain potential functional consequences of such interactions. METHODS: The model membranes examined consisted of the argon-buffer interface and monomolecular films of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) at the argon-buffer interface. Interactions with the model membranes were detected as changes in surface tension, i.e., surface pressure. Functional consequences of these interactions were assessed with natural membranes by 6-carboxyfluorescein leakage, hemoglobin release, lactate dehydrogenase release, and histamine release from appropriate cell types. RESULTS: Measurements at the argon-buffer interface revealed intrinsic surface activity for all agents that ranged from highly surface-active to weakly surface-active in the order of: desloratadine > clemastine > azelastine congruent with ketotifen > diphenhydramine> pyrilamine > emedastine > epinastine > or = olopatadine. This order of amphipathic behavior was confirmed for most of the compounds by estimates of their dissociation constants (K(d,L)) determined from interactions with SOPC monolayers adjusted to a surface pressure approximating that of natural membranes. Epinastine was the only antihistamine that showed a disproportionately greater increase in surface activity toward SOPC in monolayer when compared to other antihistamines. Dissociation constants could not be established for olopatadine because of its low affinity for both the argon-buffer interface and the SOPC monolayer. Functional consequences of these interactions were assessed with natural membranes by 6-carboxyfluorescein leakage (erythrocyte ghosts), hemoglobin release (erythrocytes), lactate dehydrogenase release (conjunctival mast cells, corneal epithelial cells), and histamine release (conjunctival mast cells). Aside from olopatadine and emedastine, all antihistamines promoted a concentration-dependent leakage of hemoglobin from intact erythrocytes. The concentration of drug required to cause half-maximal hemoglobin release (H(50)) from erythrocytes correlated linearly (r = 0.98) with the SOPC dissociation constants (K( d,L)) estimated for the different antihistaminic agents interacting with SOPC monolayers. A similarly high correlation (r = 0.85) emerged from a plot with a slope approaching unity that related drug concentrations required for half-maximal hemoglobin leakage from erythrocytes to threshold doses of drug that caused histamine release from human conjunctival mast cells. Olopatadine was the only agent that did not promote membrane perturbation as monitored by either hemoglobin release from intact erythrocytes, LDH release from human conjunctival mast cells, or 6-carboxyfluorescein release from erythrocyte ghosts. Assessment of the lytic potential of marketed concentrations of ketotifen (0.025%), azelastine (0.05%), and epinastine (0.05%) revealed significant membrane perturbation of human conjunctival mast cells and, importantly, human corneal epithelial cells as indexed by LDH release. This was in contrast to marketed concentrations of olopatadine (0.1%) which maintained normal mast cell and corneal epithelial cell membrane function. CONCLUSIONS: Combined, these results support the notion that the disruption of natural cell membranes by surface-active antihistamines occurs not through a receptor-mediated process, but is the consequence of a direct interaction of these agents with the cell membrane. This is corroborated by surface pressure-concentration isotherms for adsorption of five different antihistaminic agents to SOPC monolayers where 50% lysis occurred at a surface pressure of 42.9 +/- 1.1 mN/m. Olopatadine appears to be unique among the agents tested by demonstrating low intrinsic surface activity, thus limiting its interaction with natural membranes. At concentrations of about half-maximal compound solubility (, 5.0 mM or a 0.19% drug solution), olopatadine generated SOPC monolayer surface pressures (i.e., 39.82 +/- 0.10 mN/m) that were below those that promoted membrane perturbation and onset of hemoglobin leakage. Olopatadine's restricted interaction with membrane phospholipids limits the degree of membrane perturbation and release of intracellular constituents, including histamine, LDH, and hemoglobin, which is believed to contribute to olopatadine's topical ocular comfort and patient acceptance.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14704897&dopt=Abstract olopatadine Patanol



Patanol
Olopatadine inhibits TNFalpha release from human conjunctival mast cells.

Cook EB, Stahl JL, Barney NP, Graziano FM.

University of Wisconsin-Madison, School of Medicine, Department of Medicine, 53792, USA.

BACKGROUND: Tumor necrosis factor-alpha (TNFalpha) release likely plays a crucial role in allergic ocular inflammation via increasing ICAM-1 on epithelial cells and triggering other proinflammatory events. The immediate and prolonged release of TNFalpha from human conjunctival mast cells in response to allergen challenge is potentially an important target for therapeutic intervention, yet the effect of ocular anti-allergic agents on this process has not been examined. Olopatadine (Patanol) is a clinically effective dual-action ophthalmic anti-allergic agent that has been shown to inhibit mast cell histamine, tryptase, and PGD2 release in vitro and promote decreased H1 receptor binding activity in vitro and functional H1 receptor antagonism in vivo. OBJECTIVE: To investigate the effect of olopatadine on TNFalpha release from anti-IgE antibody challenged purified human conjunctival mast cells. METHODS: Human conjunctival mast cells were purified (>95%) from cadaveric tissues using a procedure combining enzymatic digestion and Percoll gradient centrifugation. These cells were incubated with olopatadine for 30 minutes then challenged with anti-IgE antibody for 90 minutes. Supernatants were analyzed for TNFalpha. RESULTS: Purified human conjunctival mast cells responded to anti-IgE antibody challenge with TNFalpha release in a concentration dependent manner (optimum concentration was 10 microg/mL). Olopatadine pre-incubation resulted in a dose-dependent decrease in anti-IgE antibody mediated TNFalpha release (IC50 = 13.1 microM). At a concentration of 3 mM olopatadine reduced TNFalpha release to the level of unchallenged controls. CONCLUSION: Olopatadine inhibited anti-IgE antibody-mediated release of TNFalpha from human conjunctival mast cells. This effect could contribute to the long duration of anti-allergic activity reported for the drug.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10831003&dopt=Abstract olopatadine Patanol



Patanol
The promotion of eosinophil degranulation and adhesion to conjunctival epithelial cells by IgE-activated conjunctival mast cells.

Cook EB, Stahl JL, Sedgwick JB, Barney NP, Graziano FM.

Department of Medicine, University of Wisconsin-Madison, School of Medicine, Madison, Wisconsin, USA.

BACKGROUND: Allergen-mediated mast cell activation is a key feature of ocular allergic diseases. Evidence of eosinophil-derived mediators in tears and conjunctival biopsy specimens has been associated with chronic ocular allergic inflammation. OBJECTIVE: To examine the role of conjunctival mast cell mediators in eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation. METHODS: Conjunctival cells were obtained by enzymatic digestion of cadaveric conjunctival tissues. Eosinophils were obtained from peripheral blood samples using negative magnetic bead selection. The effect of IgE-activated mast cell supernates on eosinophil degranulation and adherence to epithelial cells was compared with supernates obtained from mast cells pretreated with a degranulation inhibitor (olopatadine). Eosinophil adhesion was measured by eosinophil peroxidase assay, and eosinophil degranulation was measured by eosinophil-derived neurotoxin radioimmunoassay. RESULTS: IgE-activated conjunctival mast cell supernates stimulated adhesion of eosinophils to epithelial cells (20.4% +/- 6.3% vs 3.1% +/- 1.0%; P = .048). Degranulation was not required for this process (no effect of olopatadine). IgE-activated mast cell supernates stimulated eosinophil-derived neurotoxin release (108.89 +/- 8.27 ng/10(6) cells vs 79.45 +/- 5.21 ng/10(6) cells for controls, P = .02), which was significantly inhibited by pretreatment of mast cells with a degranulation inhibitor (79.22 +/- 4.33 ng/10(6) cells vs 61.09 +/- 5.39 ng/10(6) cells for olopatadine pretreated and untreated, respectively, P = .02). CONCLUSIONS: Mediators released from conjunctival mast cells promote eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation. Degranulation inhibition studies suggest that different mast cell mediators are involved in regulation of these events.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14756467&dopt=Abstract olopatadine Patanol



Patanol
Differential regulation of IL-4 expression and degranulation by anti-allergic olopatadine in rat basophilic leukemia (RBL-2H3) cells.

Matsubara M, Masaki S, Ohmori K, Karasawa A, Hasegawa K.

Pharmaceutical Research Institute, Kyowa Hakko Kogyo Co., Ltd., 1188 Shimotogari, Nagaizumi-cho, Sunto-gun, Shizuoka 411-8731, Japan. masahiro.matsubara kyowa.co.jp

Olopatadine hydrochloride (olopatadine) is an anti-allergic drug that functions as a histamine H(1) antagonist and inhibits both mast cell degranulation and the release of arachidonic acid metabolites in various types of cells. In this study, we examined the ability of olopatadine to inhibit the expression of cytokine genes in vitro via high-affinity receptors for immunoglobulin E in mast cells, using a rat basophilic leukemia (RBL-2H3) cell line and an in vivo mouse model. Levels of gene expression in RBL-2H3 cells were determined by semi-quantitative RT-PCR, and serum interleukin-4 (IL-4) level in mice was quantified by ELISA. Olopatadine inhibited significantly the induction of IL-4 expression by mast cells both in vivo and in vitro. Olopatadine inhibited Ca(2+) influx through receptor-operated channels (ROC) without affecting Ca(2+) release from intracellular stores. Comparative analysis of olopatadine with other anti-allergic drugs and the ROC blocker SKF-96365 demonstrated that the potency of inhibition of Ca(2+) influx correlated with the degree of suppression of degranulation and arachidonic acid release. Inhibition of Ca(2+) influx decreased phosphorylation of p38 mitogen-activated protein kinase and c-Jun NH(2)-terminal kinase, which participate in regulation of cytokine (e.g. IL-4) gene expression. However, the rank order of inhibition of Ca(2+) influx did not correspond to reduction of IL-4 expression, suggesting that an unknown mechanism(s) of action, in addition to inhibition of Ca(2+) influx, is involved in the expression of cytokines in mast cells.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15013847&dopt=Abstract olopatadine Patanol