The combined effect of topical CX-659S, a novel diaminouracil derivative, with topical corticosteroid on the three types of allergic responses in mice or guinea pigs

Betamethasone Treatment for Atopic Dermatitis in Gut Microbiota Transplanted Mice

Gut microbiota composition correlates strongly with essential disease parameters in the oxazolone-induced mouse model for atopic dermatitis. The phenotype of this model can be transferred to germ-free mice with a gut microbiota transplant to achieve high and low responding mice. Therefore, the production of high responding mice through gut microbiota transplantation may be seen as a tool to reduce group sizes or increase power in intervention studies by increasing effect size. We sought to determine whether high responding mice respond to a common treatment in the same way as low responding mice. We hypothesized that while high responding mice would exhibit a higher clinical score than low responding mice before treatment, the clinical parameters would be similar in both groups after betamethasone treatment. Dermatitis was induced with oxazolone in barrier bred Swiss Webster mice, and a high responding and a low responding donor was selected based upon clinical and pathologic scores, as confirmed by monitoring a range of ear tissue cytokines. Feces from these donors were transplanted to pregnant germ-free Swiss Webster dams, and subsequently to their offspring. Although the overall effect of betamethasone on the clinical dermatitis score and ear thickness was rather small, the high responding recipients had significantly higher clinical dermatitis score and ear thickness than the low responding recipients before treatment, and these differences vanished after betamethasone treatment. We conclude that high responding recipients can be treated to a clinical level comparable with the low responding recipients.

Fingolimod hydrochloride gel shows promising therapeutic effects in a mouse model of atopic dermatitis

OBJECTIVES

To assess the efficacy of topically applied 2% hydroxypropyl cellulose gels containing 0.5% fingolimod hydrochloride (FNGL) with or without 6% colloidal oatmeal in an in vivo model of atopic dermatitis (AD).

METHODS

AD-like lesions were induced in SKH1/Hr hairless mice and were treated with FNGL gels, non-medicated base gels and Elidel(®) cream for 6 weeks. The severity/improvement of the lesions was assessed regularly using the Eczema Area and Severity Index (EASI), pH of the skin, transepidermal water loss, g/m(2) /h (TEWL), humidity and temperature. At the end of the experiments, the plasma levels of cytokines, FNGL and white blood cells were determined.

KEY FINDINGS

The EASI score was almost unchanged for the vehicle-only groups compared to before the treatments, whereas the medicated groups showed a significant decrease in the overall EASI score (P < 0.01), although there was non-significant differences among them (P > 0.081). Both the FNGL groups also showed a significant (P ˂ 0.05) reduction in blood WBC.

CONCLUSION

This study shows that the gels containing 0.50% FNGL and FNGL 0.50% plus 6% colloidal oatmeal have potential for the treatment of AD. The presence of colloidal oatmeal may provide additional benefits.

Is pimecrolimus cream (1%) an appropriate therapeutic agent for the treatment of external ear atopic dermatitis?

Background

In recent years, pimecrolimus 1% cream has been demonstrated to reduce symptoms of atopic dermatitis in patients when applied topically.

Material/Methods

In our study we compared the therapeutic effects of local 1% pimecrolimus to 1% hydrocortisone, and to a control group in a mouse model with atopic dermatitis in the external ear canals. Atopic dermatitis was created by application of Dinitrochlorobenzene in the external ear canals of mice. The development of atopic dermatitis was detected by clinical observation score and determination of total serum IgE levels. Pimecrolimus and hydrocortisone cream were topically applied to the external ear canal skin once a day for 14 days.

Results

There was no significant difference between the hydrocortisone and the pimecrolimus therapy groups, while there was a statistically significant difference between these 2 groups and the control group (p<0.05) Assessment of the clinical observation scoring carried out on the 14th day of therapy revealed that there was no difference between the hydrocortisone and pimecrolimus groups. Biopsies were taken on the 14^th day following treatment. Tissue samples were histologically evaluated; contact dermatitis was observed microscopically in the control group, but in the therapy groups only minimal evidence of contact dermatitis was found.

Conclusions

The results of our study reveal that the therapeutic efficacy of 1% pimecrolimus was equivalent to 1% hydrocortisone treatment in the artificially developed atopic dermatitis model in external ear canals of mice. These results clearly demonstrate that 1% pimecrolimus cream can be an effective alternative therapeutic agent in cases where steroid treatment proves to be insufficient or in cases where treatment must be discontinued due to its adverse effects.

Synthesis and structure-activity relationship of tricyclic carboxylic acids as novel anti-histamines

A series of tricyclic carboxylic acids having 6-amino-pyrimidine-2,4(1H,3H)-dione with piperazino or homopiperazino moiety linked by propylene, were synthesized and evaluated for their affinity toward human histamine H(1) receptor and Caco-2 cell permeability. Selected compounds were further evaluated for their oral anti-histaminic activity in mice, bioavailability in rats, and their anti-inflammatory activity in mice OVA-induced biphasic cutaneous reaction model. Among the compounds tested, dibenzoxazepine carboxylic acid 13b showed both histamine H(1) receptor antagonistic activity and anti-inflammatory activity in vivo. In addition, 13b exhibited low affinity toward α(1) receptor and low occupancy of H(1) receptor in the brain. It is therefore, believed that 13b is a potential candidate for development as 3rd generation anti-histamine.

The phosphodiesterase 4 inhibitor AWD 12-281 is active in a new guinea-pig model of allergic skin inflammation predictive of human skin penetration and suppresses both Th1 and Th2 cytokines in mice

The selective phosphodiesterase 4 (PDE4) inhibitor AWD 12-281 is structurally optimized for topical administration. It has potent effects in models of lung inflammation if administered as a dry powder inhalation. It has also demonstrated its anti-inflammatory property in a mouse model of cutaneous inflammation after topical administration. The aim of this study was to evaluate whether AWD 12-281 may be capable of penetrating human skin. Therefore a new guinea-pig model of allergic skin inflammation had to be developed. In ovalbumin-sensitized guinea-pigs, intracutaneous administration of ovalbumin results in a rapid development of allergic skin wheals. Topically administered AWD 12-281 was capable of reducing the development of wheals, indicating that this compound can penetrate the stratum corneum of guinea-pig skin as a predictor of human skin penetration. A secondary aim was the evaluation of a T cell subtype preference of AWD 12-281 since PDE4 inhibitors are said to preferentially inhibit Th2-type cytokines. Therefore, the effects of AWD 12-281 on a broad spectrum of Th1- and Th2-type cytokines were studied in tissue homogenates after allergen challenge in sensitized mice and in supernatants of anti CD3/anti-CD28-stimulated peripheral blood mononuclear cells (PBMCs). In both models, AWD 12-281 suppressed both T cell subtype cytokines indicating a broad spectrum activity of AWD 12-281. A further issue was to determine the duration of action and the concentration-response relationship of the topical activity of AWD 12-281 using a model of acute local inflammation--the arachidonic-acid-induced mouse ear oedema. The compound exhibited a dose-dependent effect with a minimally effective concentration of 0.3%; after repeated administration the minimally effective concentration was found to be 0.03%. A single administration of a 3% solution resulted in significant suppression of inflammation even 48 h after treatment. In conclusion, our results indicate that AWD 12-281 is a very promising drug candidate not only for the treatment of lung inflammation using inhalative administration but also for the treatment of atopic dermatitis.