Age-related changes in sulfation of basement membrane glycosaminoglycans

Alterations in heparan sulfate, the principal glycosaminoglycan species in glomerular basement membrane, have been proposed as contributory to permeability changes in nephropathic disorders. In the present study, the extent of sulfation of glycosaminoglycans isolated from pronase digests of human glomerular basement membrane, obtained from subjects 15-89 years old, was examined. The sulfate to hexuronic acid ratio significantly diminished as a function of increasing age. These results suggest that decreased sulfation of glycosaminoglycans and consequent reduction in net negative charge alters permselective properties of the glomerular basement membrane with aging.