Oxidative stress and its role in psoriasis

Psoriasis is characterized by hyperproliferation and abnormal differentiation of epidermal keratinocytes, lymphocyte infiltration consisting mostly of T lymphocytes and various endothelial vascular changes in the dermal layer, such as angiogenesis, dilatation and high endothelial venule (HEV) formation. The current understanding of the molecular pathogenesis of psoriasis assigns central importance to an interaction between acquired and innate immunity. The antioxidant enzyme family of superoxide dismutases (SODs) is considered to be the first line of defense against oxygen toxicity. These metalloenzymes act to dismute toxic superoxide radicals to oxygen and hydrogen peroxide, the benefit here is that hydrogen peroxide is substantially less toxic than superoxide.However, the high levels of catalase and the absence of any therapeutic effect of antioxidant therapy make the hypothesis of oxidative stress in psoriasis far from conclusive. Therefore, we recommend further studies to measure other antioxidant enzymes as glutathione peroxidase and selenium and further therapeutic trials using multiple antioxidant therapy on a larger number of patients.