GLYCATED PROTEIN-IRON CHELATE INCREASES LIPID PEROXIDE LEVEL IN CULTURED AORTIC ENDOTHELIAL AND SMOOTH-MUSCLE CELLS

Formation of an iron chelate of glycated protein was demonstrated by t he appearance of an absorption peak at approximately 270 nm after mixi ng glycated bovine serum albumin with FeCl3. This peak disappeared and a new peak appeared at approximately 420 nm to form an isosbestic poi nt at approximately 340 nm by the addition of deferoxamine mesylate, a n iron-chelating agent, to the mixture, thus confirming the formation of the iron chelate of the glycated protein in the mixture. The lipid peroxide level was increased markedly in endothelial cells and slightl y in smooth muscle cells from bovine aorta incubated in the medium con taining glycated fetal bovine serum-iron chelate. Morphological observ ation by phase-contrast microscopy and scanning electron microscopy re vealed that the glycated fetal bovine serum-iron chelate caused intens e damage to the endothelial cells. These results indicate that glycate d protein-iron chelate provokes lipid peroxidation, which explains at least in part the mechanism of atherogenesis found in diabetic patient s.