Local therapy as basic anti-aging prevention.

摘要

Skin, the largest organ of the body, is the organ in which changes associated with aging are most visible. Intrinsic (chronologic) skin aging is characterized by atrophy of the skin with loss of elasticity and slowed metabolic activity. With superposition of environmental damage, particularly exposure to ultraviolet radiation (photodamage) on the intrinsic aging, the process results, at least initially, in hypertrophic repair response with thickened epidermis and increased melanogenesis. Even more striking changes occur in the dermis, i.e., massive elastosis (deposition of abnormal elastic fibers), collagen degeneration, and twisted, dilated microvasculature. Regular use of a sunscreen alone appears to allow for some repair as well as protection from further photodamage. Local anti-aging therapy has been shown to partially reverse the clinical and histologic changes induced by the combination of sunlight exposure and chronologic aging. Histologic changes in the epidermis and dermis noted after 12 months suggest repair of photodamage by reconstitution of rete pegs, repair of keratinocyte ultrastructural damage, more even distribution of melanocytes and melanin pigment, deposition of new papillary dermal collagen, and improvements in vasculature. Hyperkeratinization is normalized, while epidermal thickness and dermal glycosaminoglycan content are increased. Briefly, many of the unwanted changes can be improved by topical therapy.