Aging and Intrinsic Aging: Pathogenesis and Manifestations

Abstract

Cutaneous aging is a complex biological phenomenon consisting of two components: intrinsic aging and extrinsic aging. Intrinsic aging is also termed true aging which is an inevitable change attributable to the passage of time alone and is manifested primarily by physiologic alterations with subtle but undoubtedly important consequences for both healthy and diseased skin and is largely genetically determined [1]. Extrinsic aging is caused by environmental exposure, primarily to UV light, and more commonly termed photoaging. In sun-exposed areas, photoaging involves changes in cellular biosynthetic activity that lead to gross disorganisation of the dermal matrix [2]. The intrinsic rate of skin aging in any individual can be dramatically influenced by personal and environmental factors, particularly the amount of exposure to ultraviolet light. Photodamage, which considerably accelerates the visible aging of skin, also greatly increases the risk of cutaneous neoplasms. So, the processes of intrinsic and extrinsic aging are superimposed. As the population ages, dermatological focus must shift from ameliorating the cosmetic consequences of skin aging to decreasing the genuine morbidity associated with problems of the aging skin. Therefore, a better understanding of both the intrinsic and extrinsic influences on the aging of the skin, as well as distinguishing the retractable aspects of cutaneous aging (primarily hormonal and lifestyle influences) from the irretractable cutaneous aging (primarily intrinsic aging), is very important to solve the problem of aging [2].