IDENTIFICATION OF TYPE-VI COLLAGEN SYNTHESIZING CELLS IN HUMAN DIABETIC GLOMERULOSCLEROSIS USING RENAL BIOPSY SECTIONS

Although the role of extracellular matrices in the development of glom erulosclerosis has been discussed widely, the cellular origin of type VI collagen in diabetic nephropathy (DN) has remained relatively unexp lored. This study reports the distribution and cellular origin of type VI collagen in DN. Type VI collagen-specific oligonucleotide probes a nd monoclonal antibody were used to assess the relative expression of mRNA for alpha 1 (VI) chain and its translated protein in paraffin-emb edded renal biopsy sections of DN. By immunohistochemistry, compared t o the control, increased deposition of type VI collagen was noted in t he diffuse and nodular lesions of diabetic glomeruli. For cellular loc alization of type VI collagen mRNA, paraffin-embedded renal sections o f the control and DN were hybridized in situ with digoxigenin (Dig)-la beled antisense oligo-DNA probe complementary to a part of alpha 1 (VI ) mRNA. In comparison to the control kidney sections, increased number s of intraglomerular cells (both mesangial and epithelial cells) were positive for alpha 1 (VI) mRNA in renal biopsy sections of DN. From th e results, we conclude that overexpression of type VI collagen by intr aglomerular cells with its increased;deposition might significantly co ntribute to the glomerulosclerosis found in DN.