It could be shown using the in vitro cell culture aging model, that elastase-type endopeptidase activity is progressively upregulated with successive passages (in vitro aging). Similar results were obtained previously by determining elastase-type activity as a function of age in aorta extracts (human) and skin extracts (mouse). Among the possible mechanisms involved we tested the role of advanced glycation endproducts (AGEs) on this process. AGE-production was shown to increase with age, exemplified by the exponential age-dependent crosslinking of collagen, demonstrated by Fritz Verzár, already in 1963. Several AGEs significantly upregulated elastase-type activity when added to the culture medium of fibroblasts. This effect appears to be mediated by some AGE-receptors as shown previously, and could be inhibited by a 5 kDa rhamnose-rich oligosaccharide (RROP-3) as well as by a fucose-rich oligosaccharide (FROP-3). When present in the culture media, RROP-3 and FROP-3 efficiently inhibited the passage-dependent upregulation of elastase-type activity expressed by human skin fibroblasts. The use of specific inhibitors and zymography suggested that matrix metalloproteinases (MMP)-9 activation and expression are mainly involved. A detailed discussion is proposed for the interpretation of age-dependent modifications of tissues as vascular wall and skin in the light of these and related experiments, highlighting the role of several specific receptors in the mediation of the observed reactions.
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