The role of nitric oxide in skin inflammation and the pathogenesis of psoriasis.

Psoriasis is an immune-mediated disease characterized with excessive keratinocyte proliferation and inflammation. In this review, we discuss the involvement of nitric oxide (NO) in the pathogenesis of psoriasis. NO is a molecule widely described in physiological and pathological contexts. One of the best-known functions of NO is its vasodilating activity, critical for a proper functioning of the cardiovascular system. Another important effect induced by NO is a regulation of immunity. Specifically, NO can act pro- and anti-inflammatory, regulating immune cell infiltration and secretion of inflammatory mediators. Furthermore, NO regulates proliferation and differentiation of keratinocytes, a major cell population actively involved in psoriasis development. Current evidence highlights involvement of NO synthase and NO itself in pathophysiological processes associated with psoriasis.