Accumulation of fructosyl-lysine and advanced glycation end products in the kidney, retina and peripheral nerve of streptozotocin-induced diabetic rats

The accumulation of AGEs (advanced glycation end products) in diabetes mellitus has been implicated in the biochemical dysfunction associated with the chronic development of microvascular complications of diabetes – nephropathy, retinopathy and peripheral neuropathy. We investigated the concentrations of fructosyl-lysine and AGE residues in protein extracts of renal glomeruli, retina, peripheral nerve and plasma protein of streptozotocin-induced diabetic rats and normal healthy controls. Glycation adducts were determined by LC with tandem MS detection. In diabetic rats, the fructosyl-lysine concentration was increased markedly in glomeruli, retina, sciatic nerve and plasma protein. The concentrations of N^∊-carboxymethyl-lysine and N^∊-carboxyethyl-lysine were increased in glomeruli, sciatic nerve and plasma protein, and N^∊-carboxymethyl-lysine also in the retina. Hydroimidazolone AGEs derived from glyoxal, methylglyoxal and 3-deoxylglucosone were major AGEs quantitatively. They were increased in the retina, nerve, glomeruli and plasma protein. AGE accumulation in renal glomeruli, retina, peripheral nerve and plasma proteins is consistent with a role for AGEs in the development of nephropathy, retinopathy and peripheral neuropathy in diabetes. High-dose therapy with thiamine and Benfotiamine suppressed the accumulation of AGEs, and is a novel approach to preventing the development of diabetic complications.