Analysis of intra-GBM microstructures in a SLE case with glomerulopathy associated with podocytic infolding
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Systemically podocytic infolding into the GBM which causes nonargyrophilic holes in the GBM in association with intra-GBM microstructures has been considered as a new pathological entity. However, its pathomechanisms are largely unknown.
We analyzed intra-GBM microstructures in an SLE patient with glomerulopathy associated with podocytic infolding by immunoelectron microscopy for vimentin (a marker for both podocyte and endothelium) and C5b-9 and by 3D reconstruction of transmission electron microscopy (TEM) images by computer tomography method.
Immunofluorescent study showed immunoglobulin deposition in a diffuse, capillary pattern; however, electron-dense deposits like stage 3 membranous nephropathy could be found only in some capillary loops by TEM in spite of the systemic existence of podocytic infolding and the intra-GBM microstructures. Three-dimensional reconstructed images of the TEM images revealed that some of the intra-GBM microstructures made connections with the podocyte. The clustered microstructures underneath the podocyte and their surroundings looked as a whole like the degraded part of podocyte in 3D reconstructed images. Immunoelectron microscopy showed that vimentin was positive in most intra-GBM microstructures. C5b-9 was positive along the entire epithelial side of the GBM and in some microstructures, suggesting that the podocytes may be attacked by C5b-9 and that the microstructures may contain C5b-9 bound cellular membranes.
Intra-GBM microstructures may be originated mainly from the podocyte. Podotyte and GBM injuries caused by C5b-9 attack to podocytes might contribute in part to podocytic infolding and intra-GBM microstructures in this case.
KeywordsPodocyte Computer tomography Electron tomography Transmission electron microscopy Vimentin C5b-9
- 4.Furukawa H, Shimizu M, Suzuki Y, Nishio H. System for three-dimensional reconstruction of TEM images based on computerized tomography method. JEOL News. 2001;36:50–5.Google Scholar
- 6.Fujigaki Y, Kobayashi S, Nagase M, Honda N, Otawara Y, Tajima A, et al. Indentation of the glomerular basement membrane in cases with minor abnormalities. J Clin Electron Microsc. 1987;20:5–6.Google Scholar
- 9.Churg J, Sobin LH. Renal disease classification and atlas of glomerular diseases. Tokyo: Igaku-Shoin; 1982.Google Scholar
- 11.Fujigaki Y, Nagase M, Kojima K, Yamamoto T, Hishida A. Glomerular handling of immune complex in the acute phase of active in situ immune complex glomerulonephritis employing cationized ferritin in rats. Ultrastructural localization of immune complex, complements and inflammatory cells. Virchows Arch. 1997;431:53–61.PubMedCrossRefGoogle Scholar