Diabetes mellitus associated changes in glomerular glycocompounds: a fluorescence microscopical study

Renal biopsy specimens showing histological alterations typical of advanced diabetic glomerulopathy were studied for changes in glomerular glycoconjugates, using fluorochrome-coupled lectins as probes. All samples studied showed a marked reduction in the binding of Triticum vulgaris (WGA) lectin in the glomerular basement membranes. On the other hand, 'new' glomerular binding sites for the lectins of Dolichos biflorus (DBA), Helix pomatia (HPA) and Arachis hypogaea (PNA), recognizing galactosyl moieties of glycoconjugates and giving no reaction in normal glomeruli, were seen in all samples studied. In addition, Wistaria floribunda lectin (WFA), recognizing galactosyl and, N-acetylgalactosaminyl configurations in glycoconjugates, gave a typical linear binding along the glomerular basement membranes, differing markedly from its reaction with normal kidney. Ulex europaeus (UEA I) showed reduced binding in the glomeruli of diabetic nephropathy. The results show that changes in glomerular glycoconjugates may appear in diabetic nephropathy, suggesting a disturbance in the turnover of the non-reducing terminal saccharide residues. In addition, the results show that lectins are useful probes for studying these changes further.