Immunogold Labelling of Cytokines in Glomeruli in Children with Various Renal Diseases

Abstract

Precise localization of cytokines such as transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), interleukin (IL)-1 and IL-6 was observed in glomeruli using immunogold electron microscopy in 21 children with various types of renal diseases. The distribution pattern of these cytokines, as well as immunoglobulins, C3c and fibrinogen (Fg), was essentially confined to the electron-dense deposits (EDDs) regardless of their location. Frequency of positive labelling of each cytokine was different among various types of renal disorder, that is, TGF-β was found mainly in lupus nephritis (LN), membranous nephropathy and IgA nephropathy, TNF-α in LN, and IL-1 in Henoch-Schönlein purpura nephritis. IL-6 was detected only in 1 case of LN. TNF-α was also found in the cytoplasm of glomerular epithelial cells. Furthermore, in order to evaluate the relation of cytokines to mesangial expansion, extracellular matrix components such as type IV collagen, laminin and fibronectin were stained. The result was that there was no significant correlation between the signal intensity or distribution pattern of cytokines and that of extracellular matrix components. These findings indicate that these cytokines could be associated with the formation of EDDs together with immunoglobulins, C3c and Fg. The involvement of each cytokine in renal pathophysiology might also depend upon the type of renal disease. They also raise the possibility that the glomerular epithelial cells might produce or absorb TNF-α. However, these results did not show significant correlation between cytokine involvement and mesangial expansion.

Pathogenic Mechanisms in Lupus Nephritis: Nucleosomes Bind Aberrant Laminin β1 With High Affinity and Colocalize in the Electron‐Dense Deposits

“…During lupus, aberrant laminin ␤1 is produced by the endothelium and by podocytes ( Figure 5H). We also found that the TGF␤1 content was confined to the EDDs (Figures 5A-D), as previously described by other investigators using lower-resolution light microscopy (23,24). The specific ligand for TGF␤1 trapping within the EDDs, however, was not investigated in the present study.…”

“…Interestingly, TGF␤1 has also been found by us and by other investigators to be confined to the EDDs in lupus nephritis (23,24). Consumption in the kidney may reflect lower circulating levels of TGF␤1, which seem to be associated with severe disease, kidney involvement, and worse outcome in SLE (35,36).…”

“…Indeed, TGF␤1 was found in glomerular structures and cells in direct comparison with its distribution in the kidneys of transgenic animals (23). Accumulations of TGF␤1 were present in this pattern in podocytes ( Figures 5E and F) and the mesangium (Figure 5G), as well as in the extracellular spaces ( Figures 5E and F), which implies exocytosis.…”

“…Typically, 5-l samples of complexes between nucleosomes and the different laminins (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) Analysis of proteins applied to PVDF membranes. Nucleosomes were radiolabeled with 125 I using Iodo-Beads iodination reagent (Pierce).…”

Effect of tumor necrosis factor α and vascular permeability growth factor on albuminuria in rats

“…Mesangial and proximal tubular cells are known to secrete TNFa [25], and this cytokine has been detected in the glomeruli of patients with MLNS in relapse by in situ hybridization [26]. Cho et al recently reported increased urinary TNFa excretion in IMLNS patients in relapse when compared with normal controls or MLNS patients in remission [22].…”