Conjunctival mast cell as a mediator of eosinophilic response in ocular allergy

Division of Ophthalmology and Visual Science, Faculty of Medicine, Tottori University, Yonago, Japan.
Molecular vision (Impact Factor: 1.99). 02/2008; 14:1525-32.
Source: PubMed


To determine the contribution of conjunctival mast cells to the allergen-specific inflammatory responses in eyes with allergic conjunctivitis and to test the hypothesis that mast cells act as mediators of the early phase response.
The participation of mast cells in allergen-induced inflammatory cell recruitment was studied in an experimental murine model of allergic conjunctivitis. Experimental allergic conjunctivitis was induced by a single or multiple sensitizing injections of an allergen. The conjunctiva of allergen-sensitized, mast cell-deficient (Kit(w)/Kit(w-v)) mice were reconstituted with conjunctival mast cells isolated from naïve wild type mice by subconjunctival transfer. Kit(w)/Kit(w-v) mice and conjunctival mast cell reconstituted Kit(w)/Kit(w-v) mice were evaluated for early phase reactions and late phase inflammatory responses.
The early phase response was minimal in Kit(w)/Kit(w-v) mice after both a single injection and multiple sensitization injections of the allergen. The early phase responses were fully restored following adoptive transfer of isolated conjunctival mast cells from naïve wild type mice. Eosinophilic inflammatory responses were significantly depressed in Kit(w)/Kit(w-v) mice without the impairment of allergen-specific priming. Reconstitution of the conjunctiva of Kit(w)/Kit(w-v) mice with mast cells from wild type mice fully restored the allergen-specific eosinophilic responses but not the neutrophilic responses.
Our data indicate that conjunctival mast cells are essential for eosinophilic inflammation but not for neutrophilia in allergic conjunctivitis that is mediated by mast cell activation.

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Available from: Dai Miyazaki, Oct 04, 2015
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    • "This is followed by the late-phase response after 6–24 h, which involves eosinophil and neutrophil infiltration into the conjunctiva [1]. Inflammatory cells, cytokines, and proteases contribute to more serious chronic forms [2]. "
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    ABSTRACT: Glucocorticoids can either suppress gene transcription (transrepression) or activate it (transactivation). This latter process may contribute to certain side effects caused by these agents. Mapracorat (also known as BOL-303242-X or ZK 245186) is a novel selective glucocorticoid receptor agonist that maintains a beneficial anti-inflammatory activity but seems to be less effective in transactivation, resulting in a lower potential for side effects; it has been proposed for the topical treatment of inflammatory skin disorders. This study assessed the anti-allergic activity of mapracorat at the ocular level and whether eosinophils and mast cells are targets of its action. With in vitro studies apoptosis was evaluated in human eosinophils by flow cytometry and western blot of caspase-3 fragments. Eosinophil migration toward platelet-activating factor was evaluated by transwell assays. Interleukin (IL)-6, IL-8, tumor necrosis factor-α (TNF-α), and the chemokine (C-C motif) ligand 5 (CCL5)/regulated upon activation normal T cell expressed, and presumably secreted (RANTES) were measured using a high-throughput multiplex luminex technology. Annexin I and the chemochine receptor C-X-C chemokine receptor 4 (CXCR4) were detected by flow cytometry. With in vivo studies, allergic conjunctivitis was induced in guinea pigs sensitized to ovalbumin by an ocular allergen challenge and evaluated by a clinical score. Conjunctival eosinophils were determined by microscopy or eosinophil peroxidase assay. In cultured human eosinophils, mapracorat showed the same potency as dexamethasone but displayed higher efficacy in increasing spontaneous apoptosis and in counteracting cytokine-sustained eosinophil survival. These effects were prevented by the glucocorticoid receptor antagonist mifepristone. Mapracorat inhibited eosinophil migration and IL-8 release from eosinophils or the release of IL-6, IL-8, CCL5/RANTES, and TNF-α from a human mast cell line with equal potency as dexamethasone, whereas it was clearly less potent than this glucocorticoid in inducing annexin I and CXCR4 expression on the human eosinophil surface; this was taken as a possible sign of glucocorticoid-dependent transactivation. In the guinea pig, mapracorat or dexamethasone eye drops induced an analogous reduction in clinical symptoms of allergic conjunctivitis and conjunctival eosinophil accumulation. Mapracorat appears to be a promising candidate for the topical treatment of allergic eye disorders. It maintains an anti-allergic profile similar to that of dexamethasone but seems to have fewer transactivation effects in comparison to this classical glucocorticoid. Some of its cellular targets may contribute to eosinophil apoptosis and/or to preventing their recruitment and activation and to inhibiting the release of cytokines and chemokines.
    Molecular vision 12/2011; 17:3208-23. · 1.99 Impact Factor
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    • "The activation of mast cells leads to the release of powerful vasoactive amines that are responsible for the vasodilatation and increased permeability of blood vessels. In addition, the activated mast cells can recruit eosinophils to participate in the allergic reaction [29]. Conjunctival epithelium and corneal epithelium are also involved in the pathogenesis of AC. "
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    ABSTRACT: Allergic conjunctivitis (AC) has been reported to induce the instability of the tear film. The tear protein and the lipid layer play important roles in maintaining the tear film. The aim of this study was to quantify the alteration of the major tear protein components and a lipid related protein secretory type IIa phospholipase A2 (sPLA2-IIa) in tears of seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC) patients. Twenty-one SAC and PAC patients and thirteen normal controls completed a symptom questionnaire and underwent regular ocular examination. SAC and PAC patients were diagnosed based on the clinical presentation and elevated serum IgE levels. Schirmer test paper was used to collect tear samples from SAC and PAC patients and normal controls. Soybean trypsin inhibitor (SBTI) was used as an internal standard to analyze tear samples in 15% SDS-PAGE gel. Total tear protein and its major components from the SAC and PAC patients and normal controls were quantified by band densitometry. The major tear protein bands were determined by MALDI-TOF/TOF spectrum analysis. Western blot was used to detect the content of sPLA2-IIa in tears of allergic conjunctivitis patients and normal controls. Schirmer test scores were more than 10 mm in all the SAC and PAC patients and control subjects. The tear film breakup time of SAC and PAC patients was much shorter than that of the normal controls. We obtained 15 bands of tear protein by one dimensional SDS-PAGE, in which 14 bands were determined by mass-spectrum analysis. The band densitometry analysis revealed that the total tear protein concentration was much higher in SAC and PAC patients than in normal controls (p<0.05). The quantity of tear protein band 4 (serum albumin precursor), band 6 (Ig gamma-2), band 9 (leukocyte elastase inhibitor) were also significantly higher in AC patients (p<0.05). Content of sPLA2-IIa, as shown by western blot, was much higher in AC patients than in controls. The total tear protein concentration and some of the major tear protein components was increased in tears of SAC and PAC patients. In addition, the content of sPLA2-IIa in tears of SAC and PAC patients was elevated. The tear protein changes in SAC and PAC patients may contribute to instability of tear film.
    Molecular vision 10/2010; 16:2084-91. · 1.99 Impact Factor
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    • "Eosinophils and mast cells, with adhesion molecules, and sialyl Levis A-and X-positive cells are typically found in the conjunctival tissue of patients showing clinical signs of persistent allergic eosinophilic conjunctivitis (AEC) (Bacon et al. 1998) or persistent non-allergic eosinophilic conjunctivitis (NAEC) (Kari et al. 1997). These two allergy-related effector cells can activate each other, and comprise the cellular basis of a persistent conjunctival inflammation (Munitz & Levi-Schaffer 2004; Miyazaki et al. 2008). "
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    ABSTRACT: This study examines the histology of conjunctival biopsy samples from patients with persistent allergic eosinophilic conjunctivitis (AEC) or non-allergic eosinophilic conjunctivitis (NAEC). Fourteen patients with conjunctivitis and eosinophilia in cytology samples were included in the study. Seven had positive skin-prick tests (the AEC group) and seven had negative skin-prick tests (the NAEC group). Eight asymptomatic subjects with negative skin-prick tests served as a control group. In conjunctival biopsies eosinophils were identified with monoclonal antibodies. Mast cells were identified by specific immunostaining and tryptase-positive granules were counted around them. The percentage of degranulated mast cells was used as a measure of cell activation. Eosinophil and goblet cell numbers were counted, epithelial thickness was measured, and the symptoms were characterized and graded. The numbers of eosinophils in biopsies were higher in patients with AEC than in healthy controls (p = 0.010). The proportion of activated mast cells tended to be higher in AEC patients (65%) than in NAEC patients (48%) or control subjects (40%). Patients with AEC had more goblet cells than control subjects (p = 0.049) and their epithelial layer was thicker (p = 0.054). Patients with AEC had more severe symptoms than control subjects (p = 0.0005), whereas the symptoms of NAEC patients did not differ statistically from those of controls (p = 0.065). Patients with NAEC were characterized by mild eosinophilic inflammation and only minor structural conjunctival changes. The condition seems to run a relatively mild but persistent clinical course.
    Acta ophthalmologica 11/2009; 88(2):245-50. DOI:10.1111/j.1755-3768.2009.01599.x · 2.84 Impact Factor
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