The epidermis as a target for antipsoriatic treatment

Abstract

The modes of action of antipsoriatic treatments can be studied in in vitro in models, in vivo models or during treatment of psoriatic plaques. During the last decade research programmes in Nijmegen have focused on the epidermis as a target for antipsoriatic treatments. The present communication reviews aspects of epidermal growth and inflammation during the treatment of psoriasis. Both in vitro and in vivo data are reviewed. All established antipsoriatic treatments have been proved to inhibit epidermal proliferation in vitro and in vivo, except for cyclosporin. Cyclosporin is a selective immunomodulatory treatment in vivo. In contrast to the in vitro situation, during treatment of psoriatic plaques in vivo a rather consistent pattern is observed for all antipsoriatic treatments with a reduction of involucrin-, transglutaminase-and keratin 16-positive cell layers and an increase in the number of filaggrin-positive cell layers. The various antipsoriatic treatments differ mainly with respect to the modulation of cutaneous inflammation. Based on cell-biological observations some combinations of treatments can be expected to be highly effective clinically. The combination of immuno-modulating treatments with predominantly growth-inhibitory and keratinization-modulating treatments is promising. From a cell-biological point of view, highly successful combinations are the combination of dithranol and phototherapy and the combination of cyclosporin and calcipotriol.

Key Words:

• Antipsoriatic treatment
• Epidermis