Changes in renal glomerular CD34 expression with age and diabetes

CD34 is a cell adhesion molecule, sialomucin type, present in hematopoietic stem and endothelial cells. It contains consensus sites for PKC phosphorylation and has been proposed to have signaling properties. Aging and diabetes have been associated with increased inflammatory activity, concurring with the exacerbated expression of adhesion molecules. Considering the importance of adhesive molecules in endothelial dysfunction and their possible effect on the alteration of glomerular permeability, we established by quantitative immunogold the distribution of CD34 in the normal renal glomeruli and evaluated the changes in expression along with age and hyperglycemic condition. Control and diabetic rats of 3 and 12 months were used in this study. Both groups of diabetic animals as well as the 12 months‐old normoglycemic animals display alterations in glomerular perm‐selectivity with proteinuria. CD34 immunogold was mostly assigned to the glomerular endothelial luminal membrane and to mesangial cytoplasmic membrane processes. Podocytes were labelled to a much lesser degree. For the 12 months‐old normoglycemic animal group as well as for both diabetic groups, the labelings, while remaining in the same locations, increased in intensity. This increase in expression of CD34 was confirmed by western blot on isolated glomerular fractions. Being associated with endothelial and mesangial activation, the increased expression of CD34 in these compartments might reflect its involvement in the pathogenesis of glomerular alterations related to age and diabetic condition. Supported by the Canadian Institutes of Health Research.