Alterations in extracellular matrix components and integrins in patients with preeclamptic nephropathy

The glomerular features of patients with preeclampsia consist of swelling of endothelial cells, subendothelial deposits of incompletely defined material, and thickening of the capillary walls. These abnormalities are thought to resolve in the postpartum period. The distribution of extracellular matrix (ECM) components and integrins was investigated in 10 such patients. Frozen sections and paraffin-embedded sections were stained with antibodies to type IV collagen, laminin (LN), fibronectin (FN), vitronectin (VN), tenascin (TN), fibronectin receptor (FNR), and vitronectin receptor (VNR). In preeclamptic nephropathy, the accumulation of type IV collagen, LN, FN, TN, and FNR was observed in the thickened capillary walls, particularly in the subendothelial layer and, to some extent, in the mesangium. However, deposits of VN were sparse and the distribution of VNR was similar to that in normal kidney. In segmental sclerotic lesions, the amounts of type IV collagen, LN, FN, VN, and TN were increased, whereas those of FNR and VNR were markedly decreased. These results suggest that the materials deposited in the subendothelial space consist of ECM components as well as of plasma-derived proteins, and that the deposition of ECM components and of FNR may be involved in the development and the reparative process of the characteristic glomerular lesions. The formation of sclerotic lesions was linked to the accumulation of ECM components, but not to an interaction with integrins.