Passive Cutaneous Anaphylaxis Model Research Articles

Curcumin, a constituent of curry, suppresses IgE-mediated allergic response and mast cell activation at the level of Syk

Activation of mast cells through the high-affinity receptor for IgE (FcepsilonRI) underlies atopic allergic reactions. Curcumin can block this activation, but the mechanism and the effects of curcumin on IgE-mediated allergic reactions are unknown. We sought to determine the antiallergic activity of curcumin in vivo and its mechanism of action in mast cells. The antiallergic activity of curcumin was evaluated in mast cell cultures and the passive cutaneous anaphylaxis model. The effects of curcumin on mast cell signaling events were examined by using immunoblotting, immunoprecipitation, RT-PCR, and other molecular biologic approaches. Curcumin inhibited antigen-mediated activation of mast cells and passive cutaneous anaphylaxis in mice. Suppression of degranulation and secretion of TNF-alpha and IL-4 was apparent at concentrations as low as 3 micromol/L curcumin in activated mast cells. Similar concentrations of curcumin suppressed Syk-dependent phosphorylations of the adaptor proteins linker of activated T cells and Grb2-associated binder 2, which are critical for mast cell activation. Although curcumin did not inhibit the phosphorylation of Syk itself, it directly inhibited Syk kinase activity in vitro. Further downstream, activating phosphorylations of Akt and the mitogen-activated protein kinases p38, p44/42 (extracellular signal-regulated kinase 1/2), and c-Jun N-terminal kinase, which are critical for the production of inflammatory cytokines, were also inhibited. Curcumin inhibits Syk kinase-dependent signaling events in mast cells and might thus contribute to its antiallergic activity. Therefore curcumin might be useful for the treatment of mast cell-related immediate and delayed allergic diseases.

2,4,6-Trihydroxy-alpha-p-methoxyphenylacetophenone (Compound D-58) is a potent inhibitor of allergic reactions.

The authors investigated the effects of 2,4,6-trihydroxy-alpha-p-methoxyphenylacetophenone (compound D-58), a potent inhibitor of protein tyrosine kinases SYK and Bruton's tyrosine kinase (BTK), on IgE receptor/FcepsilonRI-triggered mast cell-mediated acute allergic responses in vitro and in vivo. Compound D-58 abrogated IgE receptor/FcepsilonRI-mediated SYK and BTK activation as well as calcium mobilization in mast cells. Mast-cell degranulation and leukotriene (LT) C(4) release was inhibited by compound D-58 in a concentration-dependent fashion. Notably, compound D-58 prevented the mast cell mediator-induced vascular hyperpermeability in an in vivo murine model of passive cutaneous anaphylaxis as measured by the prevention of extravasation of systemically administered Evans blue dye. The results uniquely indicate that compound D-58 has potent antiallergic properties. Therefore, further development of compound D-58 may provide the basis for new and effective treatment programs for severe allergic disorders.

Pharmacokinetics and biologic activity of the novel mast cell inhibitor, 4-(3-hydroxyphenyl)-amino-6,7-dimethoxyquinazoline in mice.

The purpose of the present study was to examine the pharmacodynamic and pharmacokinetic features of the novel mast cell inhibitor 4-(3'-Hydroxyphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P180) in mice. A high performance liquid chromatography (HPLC)-based quantitative detection method was used to measure plasma WHI-P180 levels in mice. The plasma concentration-time data was fit to a single compartment pharmacokinetic model by using the WinNonlin program to calculate the pharmacokinetic parameters. A cutaneous anaphylaxis model was used to examine the pharmacodynamic effects of WHI-P180 on anaphylaxis-associated vascular hyperpermeability. The elimination half-life of WHI-P180 in CD-1 mice (BALB/ c mice) following i.v., i.p., or p.o. administration was less than 10 min. Systemic clearance of WHI-P180 was 6742 mL/h/kg in CD-I mice and 8188 mL/h/kg in BALB/c mice. Notably, WHI-P180, when administered in two consecutive nontoxic i.p. bolus doses of 25 mg/kg, inhibited IgE/antigen-induced vascular hyperpermeability in a well-characterized murine model of passive cutaneous anaphylaxis. WHI-P180 is an active inhibitor of IgE-mediated mast cell responses in vitro and in vivo. Further preclinical characterization of WHI-P180 may improve the efficacy of WHI-P180 in vivo and provide the basis for design of effective treatment and prevention programs for mast cell mediated allergic reactions.

Effect of a 5-lipoxygenase inhibitor, ZM 230487, on cutaneous allergic inflammation in the guinea-pig.

1. Leukotrienes have potent biological effects in vitro and in vivo and are found in tissue and in biological fluids in various pathological conditions including allergic diseases. Leukotriene B4 (LTB4) is a potent stimulus for eosinophil accumulation and activation and there is much interest in determining its importance in mediating the accumulation of eosinophils at sites of allergic inflammation in vivo. In this study, we investigated the effects of a potent 5-lipoxygenase inhibitor, ZM 230487, on the accumulation of eosinophils and on local oedema formation in cutaneous inflammation in the guinea-pig. 2. The i.d. injection of increasing concentrations of arachidonic acid (AA) led to a dose-dependent accumulation of 111In-eosinophils but oedema formation was only significant at the top dose of AA tested (3 x 10(-8) mol per site). Co-injection of ZM 230487 with AA inhibited 111In-eosinophil accumulation up to 99% but the small oedema response to AA was only partially inhibited. AA-induced oedema formation was only effectively inhibited when a combination of a PAF antagonist, an antihistamine and ZM 230487 was used. 3. Local administration of the cyclo-oxygenase inhibitor, ibuprofen, partially inhibited AA-induced oedema formation suggesting that vasodilator prostaglandins may be released following i.d. injection of AA. AA-induced 111In-eosinophil accumulation was also partially inhibited by ibuprofen. 4. PAF-induced 111In-eosinophil accumulation was partially suppressed by local administration of ZM 230487. In contrast, LTB4-induced 111In-eosinophil accumulation was enhanced by ZM 230487. These data suggest that locally-released leukotrienes may modulate mediator-induced eosinophil accumulation. ZM 230487 had no effect on PAF- or LTB4-induced oedema formation. 5. ZM230487 significantly inhibited the accumulation of 111 In-eosinophils, but did not affect local oedema formation, in a passive cutaneous anaphylaxis (PCA) reaction. However, the PAF antagonist WEB 2086 either alone or in combination with ZM 230487 had no effect on "'In-eosinophil accumulation or oedema formation in the PCA reaction.6. In conclusion, it appears that a product of 5-lipoxygenase, probably LTB4, is important for the accumulation of "'In-eosinophils, but not local oedema formation, in the PCA reaction in guinea-pigskin. These data support a major role for LTB4 in allergic inflammation in the guinea-pig and make this animal (and the PCA model) suitable for studying the effects of inhibitors of leukotriene synthesis or action in vivo.

Passive cutaneous anaphylaxis in mouse skin is associated with local accumulation of interleukin-6 mRNA and immunoreactive interleukin-6 protein

We used a BALB/c model of passive cutaneous anaphylaxis (PCA), an IgE-mediated, mast cell-dependent reaction, to demonstrate the early production of the proinflammatory cytokine interleukin-6 (IL-6) mRNA and protein product. Northern blot analysis detects IL-6 mRNA I, and 2 hours after antigen challenge (dinitrophenyl 30–40 human serum albumin [DNP 30–40-HSA]) and in situ hybridization reveals that it is primarily cells with round-to-oval nuclei within the dermis (1 to 3 per high-power field) expressing IL-6 mRNA. Immunohistochemistry revealed perinuclear and cytoplasmic staining for immunoreactive IL-6 in mononuclear dermal cells and also cells within the basal keratinocyte layer. Injection of recombinant murine IL-6 (rmIL-6) either systemically or locally during antidinitrophenyl IgE skin sensitization resulted in increased vasopermeability at the PCA site after DNP 30–40-HSA. However, this increased permeability was not associated with a change in the character of the cellular infiltrate at the PCA site 8 hours later. Although the specific role of IL-6 in the generation of the allergic response remains unknown, its detection during PCA unequivocally demonstrates that IL-6 be considered one of the mediators identified in inflammation that follows allergic reactions.

Synthesis and oral antiallergic activity of carboxylic acids derived from imidazo[2,1-c][1,4]benzoxazines, imidazo[1,2-a]quinolines, imidazo[1,2-a]quinoxalines, imidazo[1,2-a]quinoxalinones, pyrrolo[1,2-a]quinoxalinones, pyrrolo[2,3-a]quinoxalinones, and imidazo[2,1-b]benzothiazoles.

4H-Imidazo[2,1-c][1,4]benzoxazine-2-carboxylic acid (3) was found to possess potent activity in the IgE-induced rat passive cutaneous anaphylaxis model which may be predictive of clinical antiallergic activity. Compared to disodium cromoglycate (DSCG, 1), 3 was less active following iv administration but unlike DSCG showed very significant oral activity. To explore the structural requirements for this activity, a range of tricyclic compounds was prepared and their activities were measured. Individual 2-carboxylic acids derived from imidazo[1,2-a]quinolines, imidazo[1,2-a]quinoxalines, imidazo[1,2-a]quinoxalinones, pyrrolo[1,2-a]quinoxalinones, pyrrolo[2,3-a]quinoxalinones, and imidazo[2,1-b]benzothiazoles showed iv activities up to 10(3) times as potent as DSCG and many of them showed significant oral activity. From these, imidazo[1,2-a]quinoxaline-2-carboxylic acid 114 has been chosen for further development.

Immediate hypersensitivity to drugs and simple chemicals: the efficacy of monovalent elicitors.

Introduction of a reactive monohaptenic chemical into the sensitized organism will not normally result in elicitation of immediate reactions. Rather, the first products of chemical conjugation to suitable carriers in vivo are monohaptenic, conjugates which are inhibitory according to the bridging concept, stating that the initiating event for mast cell and basophil activation is a cross-linking of membrane-bound antibody by dihaptenic or oligohaptenic antigen. Simple calculations and quantitative data are presented to show that built-in inhibition is indeed a powerful barrier to any rapidly occurring allergenic manifestation which depends on the formation of divalent conjugates. If and when such a reaction does nevertheless occur, special requirements have to be invoked. One possibility is that the chemical or drug as such, i.e. without conjugation to a carrier, is an elicitor of anaphylaxis. Such compounds are known in a guinea pig passive cutaneous anaphylaxis model system, but there is evidence that they may also play a role in clinical situations. These monovalent elicitors possess in addition to the haptenic moiety an auxiliary group. The auxiliary group requirements were studied in the guinea pig passive cutaneous anaphylaxis system by using synthetic peptides with an N-terminal 2-carboxy-4,6-dinitrophenyl group as the hapten and phenylalanine and modified phenylalanine at the C-terminus as auxiliary group. The conclusions are that effective auxiliary function depends on the benzene ring and neighboring carboxyl groups in selected positions. Anaphylactogenicity is high when the haptenic and auxiliary groups can act independently, i.e. when separated by a peptide chain of considerable length. Potent anaphylactogens with close linkage of the two groups have, however, also been found. It is unlikely that the passive cutaneous anaphylaxis elicitations observed here are mediated by some form of indirect bridging of membrane-bound antibody.

An experimental asthma model in unanesthetized rat, and the difference in effect of disodium cromoglycate between passive cutaneous anaphylaxis model and asthma model in rat.

We established here the experimental asthma model in unanesthetized rat, based on the observation of breathing. The effect of disodium cromoglycate (DSCG) was compared between the passive cutaneous anaphylaxis (PCA) model in rat and our experimental asthma model. The systemic anaphylaxis was elicited, in the rat passively sensitized with reaginic antibodies (reagin) against DNP-As, in response to challenge with antigen. The longer duration of expiration than that of inspiration was observed in the thoracic breathing of antigen-treated rats. The proportion of animals showing this respiratory distress in thoracic breathing (RDTB) was related to the concentration of antiserum used for the sensitization. The relation between RDTB and the concentration of antiserum was more manifest when the degree of RDTB was considered as a score. Inhibition of DSCG was dose-dependent on RDTB and reagin-induced PCA at more than 1 mg/kg. The maximal inhibition of DSCG (20 mg/kg, i.v.) on RDTB or PCA was observed when it was given 30 s before the challenge with antigen. The effect on RDTB decreased gradually with time after dose, and lasted beyond 60 min similar to the inhibitory activity of DSCG on antigen-induced asthmatic reaction in patients. Whereas, the effect on PCA decreased rapidly, and disappeared within 30 min after dose. These results indicate that RDTB is a principal indicator of respiratory distress induced by reagin, and that the effect of DSCG in asthmatics may be explained by its inhibitory activity on RDTB rather than that on PCA.