MATRIX PROTEINS WITH HIGH-AFFINITY FOR CALCIUM-IONS ARE ASSOCIATED WITH MINERALIZATION WITHIN THE ELASTIC FIBERS OF PSEUDOXANTHOMA ELASTICUM DERMIS

Citation
Mb. Contri et al., MATRIX PROTEINS WITH HIGH-AFFINITY FOR CALCIUM-IONS ARE ASSOCIATED WITH MINERALIZATION WITHIN THE ELASTIC FIBERS OF PSEUDOXANTHOMA ELASTICUM DERMIS, The American journal of pathology, 148(2), 1996, pp. 569-577
Citations number
50
Categorie Soggetti
Pathology
ISSN journal
00029440
Volume
148
Issue
2
Year of publication
1996
Pages
569 - 577
Database
ISI
SICI code
0002-9440(1996)148:2<569:MPWHFC>2.0.ZU;2-5
Abstract
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 localizin g 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, vit ronectin, bone sialoprotein, alkaline phosphatase, osteonectin, and os teopontin. In the latter two cases, antibodies against synthetic pepti des were also used. The results indicate that normal elastic fibers co ntained osteopontin, and that this protein was associated with the app arently normal elastin as well as with the needle-shaped mineral preci pitates in the elastic fibers of patients. On the contrary, significan t amounts of vitronectin, alkaline phosphatase and, less, of bone sial oprotein were associated with the polymorphous mineral precipitates in side the elastic fibers. Large amounts of osteonectin and fibronectin, together with vitronectin, were localized on the microfilament aggreg ates, which were often associated with altered elastic fibers in PXE d ermis 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 b e considered a secondary event, which could depend on the abnormal syn thesis and accumulation within the elastic fibers of proteins that are normally involved in mineralization processes.