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Topical vitamin D3 has relatively recently been introduced for the treatment of psoriasis. Synthetic vitamin D3 analogues with a high potential for inducing differentiation of cells, but with a low hypercalcemic effect have recently been developed. One such synthetic analogue of 1,25-dihydroxyvitamin D3 (calcitriol), 22-oxacalcitriol (OCT), is a novel agent for the topical treatment of psoriasis. The activity of OCT in vitro was investigated and compared with that of a series of vitamin D3 analogues as to their ability to inhibit murine T lymphocyte proliferation stimulated by con-A, to suppress IL-6 and IL-8 production by keratinocytes stimulated with IL-1alpha and TNFalpha, and to inhibit AP-1- and NFkappaB-dependent reporter gene expression. OCT inhibited the proliferation of lymphocytes and suppressed IL-8 and IL-6 production by keratinocytes to the same extent as the other vitamin D3 analogues. It also inhibited AP-1- and NFkappaB-controlled luciferase activity to the same extent as the other vitamin D3 analogues, which demonstrates its mechanism of action in the suppression of inflammatory processes.

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In the field of dermatology and plastic and reconstructive surgery, fibrin gel is regarded as a material that promotes wound healing. To test the hypothesis that fibrin may promote the growth of the epidermis, we examined its effects on the proliferation of cultured keratinocytes. Human keratinocytes were cultivated in fibrincoated wells, and the cell numbers and transforming growth factor (TGF)-α , secreted into the cultured medium, were measured. We also assessed the capacity of epidermal growth factor receptor (EGF-R) that is responsible for all known actions of TGF-α and epidermal growth factor. The keratinocytes increased dramatically in their number, and the TGF-α secretion and the binding capacity of EGF-R were also increased dramatically in the presence of fibrin. These findings suggest that fibrin supports the proliferation of keratinocytes in an autocrine fashion via EGF-R; namely, fibrin stimulates keratinocytes to secrete TGF-α, which in turn increases cell proliferation and EGF-R capacity. We propose that fibrin can support the wound healing process of the epidermis via the TGF-α /EGF-R pathway.fibrin; keratinocytes; TGF-α ; EGF-R; wound healing © 2005 Tohoku University Medical PressFibrin gel is commonly used in clinical applications, as it had been originally developed as a biological glue for wound closure and tissue fixation. Therefore, it has mainly been used to stop bleeding and the loss of bodily fluid. Recently in the fields of dermatology and plastic and reconstructive surgery, fibrin gel began to be regarded as a material that promotes the wound-healing process and results in a good take rate for epidermis grafts and in faster wound healing.There are several clinical reports on the use of fibrin gel as a wound healing promoter. Ronfard

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