Vasoactive peptides in the pathogenesis of psoriasis.

Psoriasis, a chronic inflammatory skin disease, is believed to be exacerbated by stress. The exact mechanism of this phenomenon is not fully understood, however, it has been postulated that different substances released from dermal nerve endings during stress may take part in initiation or modulation of psoriasis. One of the most interesting group of mediators are polypeptides, also named as neuropeptides, that possess vasoactive properties. It was documented that these polypeptides could not only be released from nerve endings, but may also be directly synthesised in the skin and liberated from numerous dermal cells. Moreover, these substances are not only released by different cells, but may activate various cell types showing a wide spectrum of biological actions. Thus, this complex system of interactions seems to be important component of psoriatic pathological reaction. The significant role of these neuromediators has also been postulated in other chronic skin diseases, like palmoplantar pustulosis, atopic and irritant eczema, rosacea, lichen sclerosus, vitiligo, pigmented urticaria or prurigo nodularis. Among different neuropeptides, substance P, calcitonin gene-related peptide, vasoactive intestinal peptide (VIP) and neuropeptide Y have been mostly studied in psoriasis.