Exogenous aging, otherwise called extrinsic aging, takes place in exposed areas of the body (e.g. head, neck) which are constantly influenced by various environmental factors including ionizing and non-ionizing irradiation, air pollution, natural deleterious gases (e.g. ozone and high concentrations of oxygen), smoking, invasion of pathogenic bacteria, viruses, xenobiotics and mechanical stress. Among them UV-irradiation is the most fundamental one, as it can damage skin to such an extent, that makes it seem prematurely aged (photoaging). This premature aging process is cumulative with sun exposure and affects more individuals of skin phototypes I and II.
Published in Chapter:
The Sebaceous Gland: A Model of Hormonal Aging
Evgenia Makrantonaki (Dessau Medical Center, Germany and Charité Universitaetsmedizin Berlin, Germany)
Copyright: © 2009
|Pages: 7
DOI: 10.4018/978-1-60566-076-9.ch019
Abstract
This chapter introduces an in vitro model as a means of studying human hormonal aging. For this purpose, human sebaceous gland cells were maintained under a hormone-substituted environment. This environment consisted of growth factors and sex steroids in concentrations corresponding to those circulating in young and postmenopausal women. The authors suggest that hormone decline, occurring with age, may play a significant role not only in the maintenance of skin homeostasis but also in the initiation of aging. Furthermore, skin, the largest organ of the body, offers an alternative approach to understanding the molecular mechanisms underlining the aging process.