Alterations in glomerular extracellular matrix components in glomerulonephritis

We investigated alterations in the main components of glomerular extracellular matrices, including heparansulfate proteoglycan (HS-PG), laminin, type IV collagen and fibronectin in the renal tissues of 61 patients with various types of glomerulonephritis. Indirect immunofluorescence stainings with polyclonal antibodies of these extracellular matrix components were performed. In minimal change nephrotic syndrome, no remarkable changes were observed. In membranous glomerulonephritis, non-collagenous components, such as HS-PG and laminin altered in distribution, forming spikes in stage II and circles between or around the immune deposits in stage III. These changes were observed more clearly in HS-PG and laminin than in type IV collagen. These results suggested that non-collagenous components played an important role in repairing the GBM. In membranoproliferative glomerulonephritis and IgA nephropathy, type IV collagen and fibronectin expanded in the proliferated mesangial area. These findings showed that there was a close relationship between these extracellular matrix and the progression of glomerulosclerosis. In dense deposit disease, double contour of staining of HS-PG, laminin and type IV collagen was observed along the capillary wall. These findings suggested that there were no main extracellular matrix components within the dense materials.