Administration of AGEs in vivo induces extracellular matrix gene expression

The role that advanced glycosylation end-products (AGEs) may play in the development of diabetic nephropathy is still not completely understood. In order to elucidate the nature of their effect, the consequences of exogenously administered AGEs on extracellular matrix gene expression were examined in mice by competitive PCR. Normal adult mice receiving repeated injections of AGEs had an increase in the expression of genes coding for type IV collagen and laminin in the glomeruli. The increase was accompanied by up-regulation of TGF-beta 1 but not PDGF-B expression. The expression of smooth muscle and beta-actin did not change, showing that the increase in gene expression was specific for genes implicated in the early stages of diabetic nephropathy. The co-administration of aminoguanidine, a drug that inhibits AGEs cross-links, prevented the up-regulation of gene expression in AGEs-injected mice. Thus, AGEs can induce extracellular matrix genes in the absence of hyperglycaemia.