Contri M B, Boraldi F, Taparelli F, De Paepe A, Ronchetti I P
Department of Biomedical Sciences, University of Modena, Italy.
Am J Pathol. 1996 Feb;148(2):569-77.
Ultrathin sections from the dermis of five normal subjects and from 10 patients suffering from pseudoxanthoma elasticum (PXE) were analyzed by immunoelectron microscopy with the aim of identifying and localizing proteins associated with the mineral precipitates within the altered elastic fibers. Serial sections were processed by indirect immunogold cytochemistry using primary antibodies against human fibronectin, vitronectin, bone sialoprotein, alkaline phosphatase, osteonectin, and osteopontin. In the latter two cases, antibodies against synthetic peptides were also used. The results indicate that normal elastic fibers contained osteopontin, and that this protein was associated with the apparently normal elastin as well as with the needle-shaped mineral precipitates in the elastic fibers of patients. On the contrary, significant amounts of vitronectin, alkaline phosphatase and, less, of bone sialoprotein were associated with the polymorphous mineral precipitates inside the elastic fibers. Large amounts of osteonectin and fibronectin, together with vitronectin, were localized on the microfilament aggregates, which were often associated with altered elastic fibers in PXE dermis and were never visualized in the dermis of control subjects. The results seem to indicate once more that PXE is a complex disorder of the fibroblast synthetic control. Elastic fiber mineralization might be considered a secondary event, which could depend on the abnormal synthesis and accumulation within the elastic fibers of proteins that are normally involved in mineralization processes.
对5名正常受试者和10名弹性假黄瘤（PXE）患者的真皮超薄切片进行免疫电子显微镜分析，目的是鉴定和定位与弹性纤维改变区域内矿物质沉淀相关的蛋白质。连续切片通过间接免疫金细胞化学法处理，使用针对人纤连蛋白、玻连蛋白、骨唾液蛋白、碱性磷酸酶、骨连接蛋白和骨桥蛋白的一抗。对于后两种情况，还使用了针对合成肽的抗体。结果表明，正常弹性纤维含有骨桥蛋白，且该蛋白与看似正常的弹性蛋白以及患者弹性纤维中的针状矿物质沉淀相关。相反，大量的玻连蛋白、碱性磷酸酶以及少量的骨唾液蛋白与弹性纤维内的多形性矿物质沉淀相关。大量的骨连接蛋白和纤连蛋白与玻连蛋白一起定位于微丝聚集体上，这些聚集体常与PXE真皮中改变的弹性纤维相关，而在对照受试者的真皮中从未观察到。结果似乎再次表明，PXE是一种成纤维细胞合成控制的复杂紊乱疾病。弹性纤维矿化可能被认为是一个继发事件，这可能取决于通常参与矿化过程的蛋白质在弹性纤维内的异常合成和积累。
