RESUMO
In order to investigate the relationship between intraglomerular coagulation and glomerular sclerosis, the distribution of fibrin-related antigen (FRA) in glomeruli without extracapillary lesions was examined by immunoperoxidase microscopy in 80 patients with IgA nephropathy (IgA-N). A total of 302 glomeruli were examined, including 20 with global sclerosis, 31 with segmental sclerosis (SS glomeruli), and 251 nonsclerosed glomeruli. In the nonsclerotic areas of SS glomeruli, the deposition of FRA was significantly greater than in the nonsclerosed glomeruli. In the nonsclerosed glomeruli FRA was mainly found in the mesangium, while in the nonsclerotic areas of SS glomeruli FRA was not only present in the mesangium but also in the endothelium of the glomerular capillary loops. FRA-positive microclots were also often observed attached to the endothelium of the capillaries of the nonsclerotic areas of SS glomeruli. Cross-linked FRA was also observed in the endothelium of the same capillaries using the monoclonal antibody DD3B6/22. Deposition of von Willebrand factor (vWF) was greater in the endothelium than in the mesangium in the same areas. Aggregated platelets adhering to the glomerular capillary walls in these areas were frequently detected using the monoclonal antibody P2. Such distribution of platelets and vWF showed that the endothelium of the nonsclerotic areas of SS glomeruli was more severely damaged than that of nonsclerosed glomeruli. These findings suggest that endothelial cell damage might activate the intraglomerular coagulation, which might be one of the factors in the development of global glomerular sclerosis.
Assuntos
Glomerulosclerose Segmentar e Focal/sangue , Antígenos de Plaquetas Humanas/metabolismo , Coagulação Sanguínea , Fibrina/imunologia , Glomerulonefrite por IGA/sangue , Glomerulonefrite por IGA/imunologia , Glomerulosclerose Segmentar e Focal/etiologia , Glomerulosclerose Segmentar e Focal/imunologia , Humanos , Imuno-Histoquímica , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/imunologia , Agregação Plaquetária , Fator de von Willebrand/metabolismoRESUMO
The distribution of the von Willebrand factor (vWF) as the factor-VIII-related antigen in glomeruli was examined by immunoelectron microscopy in 10 patients with idiopathic membranous nephropathy (MN), 8 patients with minimal-change nephrotic syndrome (MCNS), and 11 patients with IgA nephropathy (IgA-N). Electron-dense reaction products of vWF were observed in the endothelium and mesangium in all specimens examined. However, they were not detected in subepithelial electron-dense deposits of MN. The amount of electron-dense reaction products of vWF in the endothelium was significantly higher in MN than that in MCNS or IgA-N. This finding suggests that the glomerular endothelium in MN is the site of the local activation of coagulation and platelet aggregation system in glomerular capillary wall lesions.
