Ultrastructural immunogold studies of heparan sulphate proteoglycan in normal human glomeruli and glomerulonephritis

The distribution of heparan sulphate proteoglycans (HSPG) has been investigated in normal human glomeruli, membranous glomerulonephritis, mesangial IgA disease, and anti-glomerular basement membrane disease. HSPG was localized using anti-bovine HSPG antibody and 10 nm gold-labelled secondary antibody on paraformaldehyde-fixed, Lowicryl K4M resin-embedded kidneys. HSPG was present in all glomeruli and there was a zonation of its distribution in that it was predominantly on the epithelial aspect of the glomerular basement membrane (GBM) and mesangium with little in the central regions of the mesangial matrix. In the cases of immune complex glomerulonephritis, no HSPG was found in the electron-dense deposits. These findings contrast with our previous studies using the same technique in which type IV collagen and fibronectin were found predominantly on the endothelial aspect of the GBM.