Olopatadine hydrochloride improves dermatitis score and inhibits scratch behavior in NC/Nga mice.

BACKGROUND: Control of itch is an important issue in the treatment of atopic dermatitis (AD). Itch is mediated by a variety of pruritogens, including histamine, and promoted by neurite outgrowth in the epidermis of AD patients, probably due to the release of nerve growth factor. OBJECTIVES: We investigated the effects of orally administered olopatadine hydrochloride (olopatadine) on itching, itching mediators, and neuritogenic action in a mouse model. MATERIALS AND METHODS: NC/Nga mice were treated topically with Dermatophagoides farinae body (Dfb) extract twice weekly for 4 weeks to induce AD-like lesions. They were concomitantly given oral olopatadine, distilled deionized water, or topical tacrolimus during the last 2 weeks. RESULTS: Olopatadine significantly suppressed scratching, improved the dermatitis score, inhibited neurite outgrowth, and decreased the elevated inflammatory markers, growth factors and histamine content in the lesional skin, and serum concentration of Dfb-specific IgE. Notably, olopatadine treatment increased semaphorin 3A expression in the epidermis. CONCLUSIONS: Our study confirms the pleiotropic effects of olopatadine, i.e. inhibition of inflammation and neurite extension into the epidermis.

Calcipotriol and betamethasone dipropionate synergistically enhances the balance between regulatory and proinflammatory T cells in a murine psoriasis model.

A topical medication combining calcipotriol (Cal) and betamethasone dipropionate (BDP) has proven effective in a number of randomized controlled trials performed in patients with psoriasis, but its mechanism of action has not been fully elucidated. We investigated whether the combination of Cal and BDP (Cal/BDP) in this topical medication had a synergistic effect on psoriasis-like dermatitis and explored the underlying immunological mechanisms in a murine psoriasis model induced by application of imiquimod. Cal/BDP synergistically inhibited ear thickening induced by imiquimod compared to monotherapy with either Cal or BDP. In addition, Cal/BDP significantly suppressed the interleukin (IL)-23/IL-17-producing T (T17) pathogenic axis, including expression of IL-17a, IL-23a, IL-22 and TNF-α mRNA in skin lesions and expansion of CCR6+ γδ T17 cells in the draining lymph nodes. Notably, Cal/BDP synergistically induced regulatory CD8+ T cells and also improved the balance between regulatory CD8+ or CD4+ T cells and proinflammatory CCR6+ γδ T17 cells in the draining lymph nodes. These results suggest synergistic anti-psoriatic activity of Cal/BDP with normalization of the imbalance between regulatory CD8+ or CD4+ T cells and proinflammatory CCR6+ γδ T17 cells, which contributes to successful control of psoriasis by Cal-BDP combination therapy.

Olopatadine ameliorates rat experimental cutaneous inflammation by improving skin barrier function.

Olopatadine hydrochloride (olopatadine) is an antiallergic agent with histamine H(1) receptor antagonistic action. We investigated the possible efficacies of olopatadine on the chronic inflammatory dermatitis and the impaired skin barrier functions induced by repeated application of oxazolone in rats. Oxazolone-sensitized rats were challenged with oxazolone applied to the ear every 3 days. Olopatadine was orally administered once daily (1 and 3 mg/kg/day). The effects of the drug were quantified by measurements of ear thickness, levels of cytokines in the lesioned ear and the number of scratching episodes. As parameters of skin barrier function, transepidermal water loss (TEWL) and hyaluronic acid (HA) levels in the lesioned ear were measured. The effect of olopatadine on the production of HA by cultured dermal fibroblasts was also measured. Repeated topical application of oxazolone to rat ears induced local inflammation that was exemplified by swelling. In inflamed ears, the amount of IFN gamma increased at both the protein and mRNA level, but IL-4 levels changed minimally. Olopatadine significantly decreased ear swelling and the number of scratching episodes. The drug also significantly inhibited the increase of IFN gamma and nerve growth factor production in inflamed ears. Olopatadine significantly inhibited the increase in TEWL and the decrease in HA in lesioned ears. Furthermore, the drug stimulated the production of HA by cultured dermal fibroblasts. These results suggest that olopatadine suppressed inflammation and scratching not only by inhibiting cytokine production, but also by repairing skin barrier function.

Low systemic exposure and calcemic effect of calcipotriol/betamethasone ointment in rats with imiquimod-induced psoriasis-like dermatitis.

Vitamin D3 (VD3) analogues-containing ointments are known to occasionally cause hypercalcemia in psoriasis patients, and the frequency of hypercalcemia is suggested to vary based on the VD3 analogue used. In this study, to address the differences in calcemic effects of VD3-containing ointments, the calcemic effects of marketed VD3-containing ointments, including calcipotriol (Cal), maxacalcitol (Max), tacalcitol (Tac), calcipotriol/betamethasone dipropionate (Cal/BDP) and maxacalcitol/betamethasone butyrate propionate (Max/BBP) ointments, were evaluated in a rat model of imiquimod-induced dermatitis. The topical application of Tac, Max and Max/BBP ointments, but not Cal and Cal/BDP ointments, to the imiquimod-induced skin lesions significantly induced an increase in the serum calcium level compared with the vaseline-treated group. Calcemic effect of VD3 analogues in rats treated with VD3-containing ointments was analyzed by evaluating the expression of vitamin D receptor target genes, such as Cyp24a1, Trpv5 and CalbindinD28k, in the intestine and kidney. Real-time reverse transcription PCR (RT-PCR) analysis showed that the renal and intestinal Cyp24a1 expressions in the Cal- and Cal/BDP-treated groups were significantly lower than those in the Tac-, Max- and Max/BBP-treated groups, suggesting that systemic exposure of VD3 analogues in the Cal- and Cal/BDP-treated groups were lower than those in the other ointment-treated groups. In addition, the renal Trpv5 and CalbindinD28k expressions, calcium-transporting genes, were increased in the Max- and Max/BBP-treated groups compared with the Cal- and Cal/BDP-treated groups. Thus, because of the low systemic exposure of VD3 analogues, Cal and Cal/BDP ointments have lower calcemic effect than the other VD3-containing ointments in rats with psoriasis-like dermatitis.

Calcium effects and systemic exposure of vitamin D3 analogues after topical treatment of active vitamin D3-containing ointments in rats.

Topical agents containing vitamin D3 (VD3) analogues such as calcipotriol, maxacalcitol and tacalcitol and the combination of calcipotriol/betamethasone dipropionate (betamethasone) are prescribed for patients with psoriasis. However, they are known to occasionally cause hypercalcemia, and the frequency of hypercalcemia is suggested to vary according to the VD3 analogue used. In this study, to address the reason for these differences, the calcemic effects of maxacalcitol-, calcipotriol- and calcipotriol/betamethasone-containing ointments in rats were evaluated. The serum calcium levels in rats treated with ointments containing maxacalcitol, but not calcipotriol or calcipotriol/betamethasone, were significantly elevated, which is consistent with clinical observations. The serum concentration of VD3 analogue in rats treated with ointments containing calcipotriol and calcipotriol/betamethasone was lower than that in rats treated with maxacalcitol-containing ointment. Thus, the calcemic effects appear to be associated with the systemic exposure of VD3 analogues in rats. To understand the mechanism underlying the different systemic exposures of VD3 analogues, skin permeation and metabolic stability of VD3 analogues were evaluated. The cumulative amount of calcipotriol permeated through rat skin was significantly lower than that of maxacalcitol. On the other hand, the metabolic clearance of calcipotriol in rat hepatocytes was higher than that of maxacalcitol. Similar results were obtained using human skin and human hepatocytes. The current study demonstrates that the lower calcemic effects of calcipotriol- and calcipotriol/betamethasone-containing ointments are caused by the low systemic exposure of calcipotriol according to low skin permeability and rapid hepatic elimination after topical application.

The effects of olopatadine hydrochloride on the number of scratching induced by repeated application of oxazolone in mice.

It is suggested that atopic dermatitis is a skin disease associated with itching as subjective symptoms, and histamine H(1) receptor antagonists are used in order to prevent the itching, and the deterioration for scratch by itching. Histamine H(1) receptor selective anti-histamine olopatadine hydrochloride (olopatadine; Allelock shows consistent efficacy and safety in the treatment of allergic disorders. We investigated the possible efficacy of olopatadine on the number of scratching induced by repeated application of oxazolone in BALB/c mice. The repeated treatment of olopatadine significantly inhibited the ear swelling and the increased number of scratching. It significantly inhibited the increased production of interleukin (IL)-4, IL-1beta and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the lesioned ear. Moreover, it significantly inhibited the increased production of nerve growth factor (NGF) and substance P. On the other hand, loratadine, bepotastine and chlorpheniramine did not inhibit the ear swelling and the increased number of scratching. These results indicate that olopatadine inhibited not only the increased production of cytokines but also NGF and substance P unlike other histamine H(1) receptor antagonists. It was suggested that olopatadine suppressed the increased number of scratching by the anti-inflammatory effects. Therefore, olopatadine appears to exert additional biological effects besides its blockade of a histamine H(1) receptor.

Olopatadine hydrochloride suppresses hot flashes induced by topical treatment with tacrolimus ointment in rats.

Tacrolimus ointment is prescribed for patients with atopic dermatitis, although it is known to cause transient burning sensations and hot flashes in the applied skin. The aim of this study was to evaluate the effects of olopatadine hydrochloride (olopatadine), an antiallergic agent with a histamine H1 receptor (H1R) antagonistic activity, on the incidence of hot flashes induced by topical treatment with tacrolimus ointment in rats. Consequently, the skin temperature was increased by the topical application of tacrolimus ointment in rats, and the rise in skin temperature was inhibited by pretreatment with olopatadine in a dose-dependent manner. Inhibitory effect of olopatadine on tacrolimus-induced skin temperature elevation was significantly more potent than that of cetirizine hydrochloride, other antiallergic agent with H1R antagonistic activity, at doses in which both agents exhibit comparable H1R antagonistic activity in rats. These results suggest that H1R antagonistic activity-independent mechanism contribute to the inhibitory effect of olopatadine on tacrolimus-induced skin temperature elevation. Olopatadine also significantly inhibited increases in vascular permeability and nerve growth factor production in the skin induced by topical tacrolimus treatment. Thus, the onset of hot flashes in rats is quantitatively determined by measuring the skin temperature and olopatadine attenuates hot flashes induced by topical tacrolimus ointment in rats, suggesting that the combination application with olopatadine and tacrolimus ointment is useful for improving medication adherence with tacrolimus ointment treatment in patients with atopic dermatitis.

Mitosis-specific activation of LIM motif-containing protein kinase and roles of cofilin phosphorylation and dephosphorylation in mitosis.

Actin filament dynamics play a critical role in mitosis and cytokinesis. LIM motif-containing protein kinase 1 (LIMK1) regulates actin reorganization by phosphorylating and inactivating cofilin, an actin-depolymerizing and -severing protein. To examine the role of LIMK1 and cofilin during the cell cycle, we measured cell cycle-associated changes in the kinase activity of LIMK1 and in the level of cofilin phosphorylation. Using synchronized HeLa cells, we found that LIMK1 became hyperphosphorylated and activated in prometaphase and metaphase, then gradually returned to the basal level as cells entered into telophase and cytokinesis. Although Rho-associated kinase and p21-activated protein kinase phosphorylate and activate LIMK1, they are not likely to be involved in mitosis-specific activation and phosphorylation of LIMK1. Immunoblot and immunofluorescence analyses using an anti-phosphocofilin-specific antibody revealed that the level of cofilin phosphorylation, similar to levels of LIMK1 activity, increased during prometaphase and metaphase then gradually declined in telophase and cytokinesis. Ectopic expression of LIMK1 increased the level of cofilin phosphorylation throughout the cell cycle and induced the formation of multinucleate cells. These results suggest that LIMK1 is involved principally in control of mitosis-specific cofilin phosphorylation and that dephosphorylation and reactivation of cofilin at later stages of mitosis play a critical role in cytokinesis of mammalian cells.