%0 Journal Article
%T Skin Photoaging and the Role of Antioxidants in Its Prevention
%A Ru£¿a Pandel
%A Borut Polj£¿ak
%A Aleksandar Godic
%A Raja Dahmane
%J ISRN Dermatology
%D 2013
%R 10.1155/2013/930164
%X Photoaging of the skin depends primarily on the degree of ultraviolet radiation (UVR) and on an amount of melanin in the skin (skin phototype). In addition to direct or indirect DNA damage, UVR activates cell surface receptors of keratinocytes and fibroblasts in the skin, which leads to a breakdown of collagen in the extracellular matrix and a shutdown of new collagen synthesis. It is hypothesized that dermal collagen breakdown is followed by imperfect repair that yields a deficit in the structural integrity of the skin, formation of a solar scar, and ultimately clinically visible skin atrophy and wrinkles. Many studies confirmed that acute exposure of human skin to UVR leads to oxidation of cellular biomolecules that could be prevented by prior antioxidant treatment and to depletion of endogenous antioxidants. Skin has a network of all major endogenous enzymatic and nonenzymatic protective antioxidants, but their role in protecting cells against oxidative damage generated by UV radiation has not been elucidated. It seems that skin¡¯s antioxidative defence is also influenced by vitamins and nutritive factors and that combination of different antioxidants simultaneously provides synergistic effect. 1. Introduction Unlike chronological aging, which is predetermined by individual¡¯s physiological predisposition, photoaging depends primarily on the degree of sun exposure and on an amount of melanin in the skin. Individuals who have a history of intensive sun exposure, live in sunny geographical areas, and have fair skin will experience the greatest amount of ultraviolet radiation (UVR) skin load and consequently severe photoaging [1, 2]. Clinical signs of photoaging include wrinkles, mottled pigmentation (hypo- or hyperpigmentation), rough skin, loss of the skin tone, dryness, sallowness, deep furrows, severe atrophy, telangiectasias, laxity, leathery appearance, solar elastosis, actinic purpura, precancerous lesions, skin cancer, and melanoma [3, 4]. Sun-exposed areas of the skin, such as the face, neck, upper chest, hands, and forearms, are the sites where these changes occur most often [5]. Chronological skin aging, on the other hand, is characterized by laxity and fine wrinkles, as well as development of benign growths such as seborrheic keratoses and angiomas, but it is not associated with increased/decreased pigmentation or with deep wrinkles that are characteristic for photoaging [6]. Seborrheic keratoses are regarded as best biomarker of intrinsic skin aging since thier appearance is independent on sun exposure. While intrinsically aged skin does not
%U http://www.hindawi.com/journals/isrn.dermatology/2013/930164/