Skin aging: brief update on biological basis
Aging is a natural process leading to the progressive deterioration of the organs and its resultant clinical and histological changes. Many contributing intrinsic and extrinsic factors are involved in this complex process. Intrinsic aging is described as a result of genetic factors that occur during the normal aging process, whereas extrinsic aging focuses on aging process accelerated by environmental influences. Skin aging reflects the whole body aging, and also for skin we talk about chronoaging ( intrinsic aging) and photoaging ( extrinsic aging, with UV irradiation as the major driver). Oxidative stress in skin plays a major role in the aging process. This is true for intrinsic aging and even more for extrinsic aging. Among other factors that contribute to aging , there is the influence of hormonal changes after menopause. Here we briefly describe the biological, clinical and histological changes that occur in the skin with age.
Aging is a complex and multifactorial process, reflecting biological, environmental, and genetic influences. It is multidimensional, comprising physical, psychological, and social change that is also influenced by cultural and societal standards. In addition to inherited genetic traits, a multitude of other factors can modify the aging process, such as hormonal status and climatic, working, social, and cultural conditions (1). The skin,
the most exposed organ to the external environment and also the most visible, is the first indicator of aging of the whole organism. As for other organs, also skin aging is the result of the sum of intrinsic factors, related to the individual genetic background, and extrinsic factors, related to environmental exposure and personal habits. From a biological point of view, the aging process in the skin is driven by reactive oxygen species (ROS) to an extent that is not attained in any other organ (2). ROS are physiologically produced during several organic processes, as the mitochondrial Electron Transport Chain, the β-oxidation of fatty acids, the Fenton reaction, and by such enzymes as cyclooxygenases, lipox ...