Remodeling of elastic fiber components in scleroderma skin

The skin of patients with scleroderma is characterized by an excess accumul ation of collagen in the extracellular matrix of the fibrotic reticular der mis, Elastic fibers are also disrupted in this disease, however, in contras t to collagen, relatively few studies have provided information concerning the changes that occur to elastic fiber components in scleroderma, In the p resent study, the extracellular matrix in scleroderma skin was examined wit h a specific focus on the integrity of elastic fibers, Electron microscopic observations confirmed an excess of 10 nm microfibrils present in small bu ndles independent of amorphous elastin in the fibrotic reticular dermis, In the same area, a population of stellate-shaped fibroblasts was identified in close association with the dermal elastic fibers. In contrast to the uni form black appearance of the elastic fibers seen in the papillary dermis an d in areas of the reticular dermis not infiltrated by these cells, the elas tic fibers apposed to the cells were mottled in density and often almost el ectron-lucent, These observations suggest that the elastic fibers in the re ticular dermis mere being actively degraded. Results from this study provid e evidence for disintegration of elastic fibers in the skin of scleroderma patients and suggest the possibility that degradation products from the ela stic matrix in the diseased tissues may act as a feedback signal for increa sed matrix production.