ELASTIC FIBER-ASSOCIATED PROTEINS OF SKIN IN DEVELOPMENT AND PHOTOAGING

We sought to use antibodies against structural (tropoelastin, fibrilli n) and nonstructural (decay-accelerating factor [DAF], serum amyloid P [SAP]) components of elastic fibers to characterize fiber structure i n neonatal skin, normal adult skin and adult skin with solar elastosis from advanced photoaging. We found by immunohistochemistry and by wes tern blotting that DAF, unlike SAP, is present on cutaneous elastic fi bers in neonates and young children, suggesting that DAF may play an e arly, integral role in protecting elastic fibers from destruction by c omplement, The most superficial portion of oxytalan fibers stained wit h antibodies against fibrillin and DAF, while anti-tropoelastin staine d only the deeper portion of oxytalan fibers, This suggests that deep oxytalan fibers are composed of both elastin and microfibrils, while t he most superficial component is composed solely of microfibrillar pro teins, Solar elastosis showed increased fibrillin, DAF, tropoelastin a nd SAP. Thus, solar elastosis is composed of both microfibrillar and e lastin proteins.