Intrinsic aging/photoaging-dependent changes of GAG in human skin

Abstract

Glycosaminoglycans (GAGs) are one of the major components in the human skin tissue, however, their agingor photoaging-related changes in skin are not well-defined and controversial. GAGs are thought to have structural functions, but their physiological functions are recently reported. To investigate intrinsic aging/photoaging-dependent changes of GAG in human skin, sun-protected buttock and sun-exposed forearm skins were biopsied from healthy young (20–39 year, n=16) and old (70–89 year, n=16) male and female volunteers (total n=32). In the dermis and epidermis, respectively, tissue water content, total uronic acid (UA) amount, total sulfated GAG (sGAG) amount, and hyaluronic acid (HA) amount were measured. Total UA amount, HA amount, and tissue water content of buttock dermis showed no change in old groups, but showed significant increase in the forearm dermis. However, total sGAG amount was decreased in both old buttock and forearm dermis. In epidermis, total UA amount, tissue water content, and total sGAG amount decreased in both buttock and forearm of old group, except in the buttock of old males. HA amount of the epidermis decreased in all the groups except in the forearm of old females. These series of investigations about GAG changes in skin aging process probably provide more fundamental understandings about the functions of GAGs in human skin.