Age Differences in Human Skin Collagen
Aging of the skin must be divided into endogenous aging and photo aging. We investigated compositional differences in the collagens of (photo-) aged skin. The results were compared with the qualitative collagen synthesis of (photo-) aged fibroblasts. There is no difference in the relative proportion of type-Ill to type-I collagens in skin extracts and cell cultures from young and old sun-protected areas. In photo aged skin there is an increase of the extractable type III. This increase was not detected in cell culture. These differences may be explained by photo-induced changes during the process of cross-linking. Modified intermolecular cross-links influence the susceptibility of collagens to collagenase attack. UV-aged cells showed a higher collagenase production, so a slower cleavage of type-III collagen would result in an accumulation of this type in the tissue.
KeywordsAged Skin Skin Extract Photoinduced Change Extractable Type Photoaged Skin
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