The role of redox regulation in the normal physiology and inflammatory diseases of skin.

Skin is the largest organ which contains complex and tightly regulated redox network of the reactive oxygen/nitrogen/lipid species producing components as well as the redox damage protective systems. This redox balancing system has evolved to regulate normal physiological processes and to protect skin and the internal organs against environmental damage. Exposure to some physical, chemical, and biological agents results in the excessive formation of free radicals and non-radical redox active species within the skin. Normally, skin reacts to this overproduction by sacrificing non-enzymatic antioxidants and by adaptive induction of both protective detoxifying and damage-eliminating systems. Thus, fast restoration of redox balance necessary to maintain normal skin structure and functioning occurs. In the case of excessive exposure or defects in the adaptive reactions, redox damage to skin components occurs. Here, we focus on the role of redox status in the acute inflammatory response to wounding and chronic inflammatory skin diseases such as psoriasis, atopic and contact dermatitis. Redox-mediated chronic inflammation and immunosuppression as risk factors for tumorigenesis are also reviewed.