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Original Article


Emedastine Difumarate Inhibits Histamine-Induced Collagen Synthesis in Dermal Fibroblasts


H Murota,1 S Bae,2 Y Hamasaki,3 R Maruyama,4 I Katayama1

1Department of Dermatology, Course of Integrated Medicine, Osaka University School of Medicine, Osaka, Japan
2Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
3Department of Dermatology, Dokkyo University School of Medicine, Tochigi, Japan
4Maruyama Dermatology Clinic, Tokyo, Japan

J Investig Allergol Clin Immunol 2008; Vol. 18(4): 245-252



Background: Mast cell-derived histamine is known to act on dermal fibroblasts and contribute to formation of an intractable chronic allergic dermatitis. Although this fibrotic event may also occur in other organs such as the nasal mucosa, no direct evidence has been reported as to whether responsiveness to histamine by fibroblasts derived from different organs is of the same intensity. Furthermore, while type 1 histamine receptor (H1R) blockers have been shown to be effective for alleviation of the symptoms of allergic diseases, their ability to affect histamine-induced tissue remodeling has not yet been clarified.

Objective: Our aim was to study the effect of H1R-blockers on histamine-induced tissue remodeling.

Methods: A macroarray assay was used for a comprehensive analysis of histamine–induced gene expression by normal human fibroblasts.
Fibroblasts derived from skin or nasal mucosa were cultured in the presence of various concentrations of histamine, and the synthesis of type 1 collagen was measured by means of semi-quantitative reverse-transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. To determine the effect of H1R blockers, diphenhydramine hydrochloride and emedastine difumarate were investigated in this assay.

Results: Histamine induced expression of various kinds of fi brogenic molecules in fibroblasts. Increased type 1 collagen expression was observed in fi broblasts treated with high-dose (0.1 mM to 1 μM) and low-dose (1 pM) histamine. This histamine-induced type 1 collagen synthesis was effectively diminished by emedastine difumarate. While organ specificity seems to be involved, emedastine difumarate is considered to be an effective drug for reversal of such histamine-induced remodeling in the skin.

Conclusions: We found that the expression of fibroblast-derived genes is differentially regulated by different concentrations of histamine and that the robustness of the inhibitory action of H1R blockers is different for skin-derived and nasal mucosa-derived fibroblasts. We believe that our findings may contribute to a better understanding of the mechanisms of histamine-induced tissue remodeling and provide information useful for the management of refractory allergic dermatitis.

Key words: Histamine. Fibroblasts. Collagen. Antihistamines. Emedastine difumarate. Tissue remodeling. Atopic dermatitis.