Immunohistochemical Study on Expression of Extracellular Matrix Components in Glomerular Diseases

ABSTRACT

Most glomerular lesions are associated with qualitative and quantitative alterations of the extracellular matrix components, having relation to progressive glomerular sclerosis. We aimed to investigate the characteristic alteraltions in distribution of extracellular matrix components, such as fibronectin, laminin, collagen type III and IV in human glomerular diseases by immunohistochemical method. The materials included are 3 nephrectomy as normal control, 51 renal biopsies and I autopsy; 3 normal, 5 minimal change disease, 5 minimal change disease with minimal mesangial lgA deposit, 5 benign recurrent hematuria, 10 focal segmental glomerulosclerosis, 15 lgA nephropathy, 10 membranoproliferative glomerulonephritis, 2 diffuse mesangial sclerosis of infancy. Type IV collagen and laminin were present normally in the mesangium, GBM, TBM and interstitial vessels, and were increased at the portion of increased mesangial matrix, of sclerosis and thickened GBM in cases of lgA nephropathy, membranoproliferative glomerulonephritis, focal segmental glomrulosclerosis and diffuse mesangial sclerosis in the proportion to the glomerular damage. Type III collagen was absent in the normal glomeruli, but was detectable focally and segmentally in cases of membranoproliferative glomerulonephritis, IgA nephropathy and focal segmental glomerulosclerosis at the sclerotic portion. Fibronectin was normally detectable mainly in the mesangium, and partly and incompletely in GBM, and was increased at the portion of increased mesangial matrix, sclerosis and thickened GBM in cases of focal segmental glomerulosclerosis, membranoproliferative glomerulonephritis, IgA nephropathy and diffuse mesangial sclerosis, but was diminshed at the old slcerotic portion or global sclerosis. The expression of these antibodies in cases of minimal change disease, minimal change disease with minimal mesangial IgA deposit, benign recurrent hematuria was not different, quantitatively and qualitatively, from that of normal glomeruli. These findings suggest that progressive glomerular sclerosis was due to the increase of extraceuular matrix components such as type IV collagen, laminin, fibronectin and new appearance of type III collagen, and the expression was in proportion to the degree of sclerosis, but had no relation to the disease entity.