Preferential downmodulation of certain chemokines by fexofenadine in human keratinocytes

Topical application of Rehmannia glutinosa extract inhibits mite allergen-induced atopic dermatitis in NC/Nga mice

AIM OF THE STUDY

Rehmannia glutinosa is known in Asia as a traditional herbal medicine with anti-inflammatory properties. Atopic dermatitis (AD) is an inflammatory skin disease associated with enhanced T-helper 2 (Th2) lymphocyte responses to allergens that results in elevated serum IgE levels and leukocyte infiltration. Although some studies have shown that Rehmannia glutinosa extract (RGE) has anti-inflammatory and anti-allergic activities, these properties have not been demonstrated in AD. This study investigated the effectiveness of RGE as a therapeutic candidate in an AD model as well as its underlying mechanism of action.

MATERIALS AND METHODS

The effects of RGE on mite allergen (Dermatophagoides farinae)-treated NC/Nga mice were evaluated by skin symptom severity, ear thickness, production of serum IgE and histamine, and expression of cytokines, chemokines, and adhesion molecules in the ear lesions. In addition, the levels of thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), and regulated on activation, normal T cell expressed and secreted (RANTES) produced in both TNF-α- and IFN-γ-stimulated human keratinocytes were investigated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

RGE treatment of NC/Nga mice significantly reduced dermatitis scores, ear thicknesses, and serum histamine levels. Histological analyses demonstrated decreased thickening of the epidermis/dermis as well as dermal infiltration by inflammatory cells. In the ear lesions, mRNA expression levels of IL-4, TNF-α, VCAM-1, and ICAM-1 were inhibited by RGE treatment. RGE also suppressed the production of TARC, MDC, and RANTES in both the ear lesions and keratinocytes.

CONCLUSIONS

RGE inhibits the development of AD in NC/Nga mice by suppressing the expression of cytokines, chemokines, and adhesion molecules.

Inhibitory effects of Cinnamomum cassia extract on atopic dermatitis-like skin lesions induced by mite antigen in NC/Nga mice

AIM OF THE STUDY

Cinnamomum cassia (C. cassia) has been traditionally used to treat allergic disease as well as dyspepsia, gastritis, and blood circulation disturbances. However, the antiallergic properties of C. cassia have not been fully verified using scientific tools. This study investigated the effectiveness of C. cassia extract (CCE) as an antiallergic agent in atopic dermatitis model and underlying mechanism.

MATERIALS AND METHODS

The effect of CCE on mite antigen-treated NC/Nga mice was evaluated by examining skin symptom severity, levels of serum IgE, tumor necrosis factor-α (TNF-α), and histamine, skin histology, and mRNA expression of cytokines in the skin lesions. Moreover, the effect of CCE on TNF-α-and interferon-γ (IFN-γ)-induced chemokine production in human keratinocytes was investigated using ELISA.

RESULTS

CCE treatment of NC/Nga mice reduced the dermatitis score and the levels of serum IgE, histamine, and TNF-α. Histological examination showed inhibition of the thickening of the epidermis/dermis and reduced dermal infiltration of inflammatory cells. In skin lesions, mRNA expression of IL-4, TNF-α, and thymus and activation-regulated chemokine (TARC) was inhibited by CCE treatment. The production of TARC, macrophage-derived chemokine, and RANTES from IFN-γ-and TNF-α-stimulated human keratinocytes was suppressed by CCE treatment in a dose-dependent manner.

CONCLUSIONS

CCE inhibits the development of atopic dermatitis-like skin lesions in NC/Nga mice by suppressing the T-helper 2 cell response.

Epidermal chemokines and modulation by antihistamines, antibiotics and antifungals

Growing evidence has demonstrated that chemokines released from epidermal cells control inflammatory skin diseases. Keratinocytes elaborate both Th1- and Th2-associated chemokines, although the former is more abundantly produced than the latter. Downmodulation of keratinocyte production of chemokines is one of the therapeutic approaches for cutaneous inflammatory disorders. Recent observations have shown that keratinocyte chemokine production can be modulated by well-used drugs, including antihistamines, antibiotics and antifungals. Utilization of the beneficial side effects of these drugs may by clinically valuable.

Fexofenadine, an H1-receptor antagonist, partially but rapidly inhibits the itch of contact dermatitis induced by diphenylcyclopropenone in patients with alopecia areata

Antihistamines have been used for the treatment of not only allergic diseases such as allergic urticaria and rhinitis, but also of eczematous skin diseases because of their anti-pruritic effects. Moreover, the pruritus associated with eczematous diseases is considered to be induced, in part, by histamine. However, it is unclear whether antihistamines inhibit the itch of eczematous diseases in the absence of topical corticosteroids. In this study, we investigated the anti-pruritic effect of the antihistamine, fexofenadine, on the itch of contact dermatitis that was induced by topical application of diphenylcyclopropenone for the treatment for alopecia areata. Thirteen patients with alopecia areata, who had been treated weekly with topical immunotherapy with diphenylcyclopropenone for 3 months to 2 years, recorded the severity of their itching on a visual analog scale before and 3, 6, 12, 24, 48 and 72 h after application of diphenylcyclopropenone for 4 consecutive weeks. Seven patients took fexofenadine during the first and third weeks, and six patients took fexofenadine during the second and fourth weeks. The severity of itching reached a maximum 6-12 h after the induction of the contact dermatitis in most of the patients. However, fexofenadine partially but rapidly reduced the severity of itching for 72 h during the entire period of treatment in the absence of topical corticosteroids. Our results suggest that fexofenadine can be beneficial in the daily management of patients with itching due to eczematous disease.

The various effects of four H1-antagonists on serum substance P levels in patients with atopic dermatitis

Antiallergic drugs have various actions against allergy-associated cells and molecules as well as antihistamic properties. We studied the effects of antiallergics on the serum levels of substance P. Patients with atopic dermatitis were treated with one of four oral H1-antagonists for 14 days, and the serum level of substance P was measured before and after treatment in parallel with several atopic severity markers. Olopatadine significantly decreased the substance P level. This is in accordance with its known downmodulatory effect on tachykinin release. In contrast, cetiridine and fexofenadine unexpectedly increased the substance P level. In patients administered cetiridine, the blood severity markers for atopic dermatitis, including lactate dehydrogenase, eosinophil number, and the soluble forms of IL-2R, E-selectin, VCAM-1 and ICAM-1 were reduced after the treatment. Therefore, the elevation of SP was unrelated to the deterioration of atopic dermatitis but rather associated with improvement. Our study suggests that antiallergics can be divided into substance P-increasing and -decreasing types and raises the possibility that the increment of substance P by the former type is caused by the competitive occupation of substance P receptors.