HYALURONIC-ACID IN CUTANEOUS INTRINSIC AGING

Background. In elderly individuals all components of the skin and subcutaneous tissue undergo histologic and ultrastructural changes. The turgidity of the dermis appears decreased, presumably due to altered patterns and levels of glycosaminoglycans (GAGS), especially hyaluronic acid and dermatan sulfate that are the most common. A linear, age-related decrease in the content Of GAGS (Mainly hyaluronic acid) has been hypothesized in human aged skin. Methods. We used the cationic dye Alcian Blue to selectively stain hyaluronic acid within the dermis in old and young subjects to compare ultrastructurally its topography and variations with age. Results. We demonstrated a progressive reduction in the number of electron-dense granules of hyaluronic acid and of their filaments until they were completely absent in subjects aged 60. Conclusions, We propose that the variations of the levels of hyaluronic acid in the dermis in aging could account for some of the most striking alterations of the aged skin, including decreased turgidity, less support for microvessles, wrinkling, and altered elasticity.