Skin Aging: Oxidative Stress and Glycative Stress

Abstract

Regarding to the pathogenesis of skin aging, oxidative stress, i.e. photoaging, and glycative stress play a significant role. Once skin is exposed to ultraviolet (UV) rays, various kinds of skin damage occurs, mediated by reactive oxygen species (ROS) and free radicals. The stimulated melanin production in pigment cells damages DNA in keratinocytes and participates in spot formation. The stimulated fibroblast production is involved in wrinkle formation. Glycative stress, a secondary factor for skin aging, is a pathophysiological condition attributed to the excessive production of reducing sugar, lipids and alcohol-derived aldehydes. The aldehyde reacts with biological materials to form carbonyl proteins and/or advanced glycation end-products (AGEs). Furthermore, AGEs bind to RAGE (receptor for AGEs) and stimulate inflammatory cytokines in immune-response cells and fibroblasts. The glycative stress causes regressive changes related to skin aging. Glycated collagen participates in the reduction of skin elasticity and glycated elastin promote slack skin. Recent reports show AGEs stimulate pigment cells to produce melanin, probably participating in spot formation. The development of anti-glycative cosmetics is important and expected in future.