Skin inflammation

Ultraviolet-induced Skin Inflammation 4.1 Role of Phagocytes... 

Under normal physiological conditions, therefore, antioxidant defences in the skin are able to modulate free-radical production. The initiation of an inflammatory event has the potential for increasing ROS production to such an extent that defence systems are overwhelmed and tissue damage occurs. This event results in the production of even more toxic oxidants and the development of overt disease requiring treatment. Section 4 of this chapter will describe the role of ROS in skin inflammation. 

Skin inflammation is invariably associated with itching and lesions tend to be traumatized by scratching. This causes bleeding into tissues leading to haemoglobin... 

In mouse models of skin inflammation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), there is a close association between elevated XO activity in the epidermis and hyperplasia (Pence and Reiners, 1987). This association is also seen in psoriasis patients (Eisen and Seegmiller, 1961 Zimmer and Demis, 1966 Kizaki et al., 1977). In the study by Kizaki etal. (1977), the epidermis was increased about five-fold in comparison to normal. It is not known whether XO-derived ROS have any role in psoriatic epidermal hyperproliferation but low levels of hydrogen peroxide added to the culture medium are well known to induce skin fibroblast proliferation in vitro, an eflfect that is greatest at low passage numbers (Murrell et al., 1990). The generation of... 

Skin inflammation induced by reactive oxygen species (ROS) an in vivo model. Br. J. Dermatol. 125, 325-329. 

Homey B, Alenius H, Muller A, et al. CCL27-CCR10 interactions regulate T cell-mediated skin inflammation. Nat Med 2002 8 157-165. 

Gombert M, Dieu-Nosjean MC, Winterberg F, et al. CCL1-CCR8 interactions an axis mediating the recruitment of T cells and Langerhans-type dendritic cells to sites of atopic skin inflammation. J Immunol 2005 174(8) 5082-5091. 

NGF has effects on the physiological responses of mature neurons. NGF acts as a target-derived trophic factor for pain neurons, which innervate peripheral tissues such as the skin. Inflammation of these peripheral tissues leads to local elevation of NGF synthesis and abundance. Elevated concentartions of NGF are responsible for the enhanced sensitivity to pain that accompanies inflammation. This is due to the ability of NGF to lower the sensory threshold of the pain fibers, leading to hyperalgesia. Nocioceptive sensory neurons mediating pain sensation are entirely dependent upon NGF for their survival as these cells are selectively lost in animal in which either the NGF or TrkA genes have been knocked out. These animals are insensitive to pain and live only a few weeks. 

Dubois B, Chapat L, Goubier A, Papiernik M, Nicolas J-F, Kaiserlian D Innate CD4+CD25+ regulatory T cells are required for oral tolerance and inhibition of CD8+ T cells mediating skin inflammation. Blood 2003 102 3295-3301. 

Seidel-Guyenot W, Perschon S, Dechant N, Alt R, Knop J, Steinbrink K Low zone tolerance induced by systemic application of allergens inhibits Tcl -mediated skin inflammation. J Allergy Clin Immunol 2006 117 1170-1177. 

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