Cutting Edge on Molecular Mechanisms of Skin Ageing and Its Rational Anti-Aging Treatments and Pathogenesis of Atopic Dermatitis

This book explores a physiological and biochemical basis for atopic phenotypes in terms of the abnormality of the barrier and water functions in the stratum corneum and its associated factors such as ceramides and its metabolites. Biological effects of the xanthophyll carotenoid astaxanthin (AX) to prevent UV-induced cutaneous inflammation, abnormal keratinization, pigmentation and wrinkling in a reactive oxygen species depletion-independent manner even by its post-irradiation treatment. The study determined the corresponding intracellular signaling mechanisms in human keratinocytes (HKs) and human melanocytes (HMs). The findings strongly supported the hypothesis that unknown tumorigenic factors due to possible cumulative DNA damage caused by previous repeated UVB exposures triggers keratinocytes to continuously produce TNF. The study also indicated that the upregulated activity of skin fibroblast-derived elastase plays a pivotal role in wrinkling and/or sagging of the skin via the impairment of elastic fiber configuration and the subsequent loss of skin elasticity. Regarding the melanocyte activation mechanisms and therapeutic topical treatment, based on the above findings of the melanocyte activation mechanism in SLs as well as the clinical efficacy obtained using an endothelin signaling blocker and a tyrosinase inhibitor, it is strongly suggested that combined treatment of an endothelin signaling blocker and a tyrosinase inhibitor is a desirable therapeutic treatment.