Tacalcitol (1,24(OH)2D3, TV-02) inhibits phorbol ester-induced epidermal proliferation and cutaneous inflammation, and induces epidermal differentiation in mice.

In this study, we examined the cutaneous effects of tacalcitol [1,24(R)(OH)2D3] on epidermal proliferation, differentiation, and skin inflammation in vivo using hairless mice. Tacalcitol was shown to inhibit epidermal proliferation using TPA-induced ornithine decarboxylase activity and DNA synthesis as indices, and the induction of epidermal differentiation using type I transglutaminase activity as an index. Tacalcitol also displayed an antiinflammatory effect on TPA-induced inflammatory changes histopathologically. These results confirm the clinical efficacy of tacalcitol in psoriasis, and suggest that it may be efficacious in the treatment of other inflammatory skin diseases.