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The present study aims at finding correlations between certain biochemical and biophysical blood parameters for diabetes patients, focusing on the antioxidant status of the red blood cells and the membrane fluidity of peripheral blood mononuclear cells (PBMC), the endothelial function and the risk of stable interaction between the leucocytes and the endothelium. For that purpose we evaluated blood samples from 32 diabetes patients compared to a control group of 10 subjects for erythrocytes’ enzymatic activity of glucose-6-phosphate dehydrogenase and of superoxide dismutase, their susceptibility to lipid peroxidation, the plasma nitric oxide stable end products level and the PBMC membrane fluidity. Our results showed that the erythrocytes’ antioxidant mechanisms and the PBMC membrane fluidity are impaired under chronic hyperglycemic conditions. Since microvascular complications of diabetes are mainly determined by redox mechanisms, the evaluation of these parameters might help in characterizing th...

A major pathway for detoxification of the highly reactive lipid peroxidation product, 4-hydroxy-2,3- trans -nonenal (HNE) is through the conjugation with glutathione (GSH). We have studied the metabolism of GS-HNE conjugate by the enzyme gamma-glutamyltranspeptidase (GGT) using its purified form, as well as a GGT-overexpressing fibroblast cell line (V79 GGT). Using mass spectrometry analysis we identified for the first time cysteinylglycine-HNE (CysGly-HNE) as the GGT metabolite of GS-HNE. Furthermore, the GGT-dependent metabolism of GS-HNE in the V79 GGT cell line was associated with a considerable increase of cytotoxicity as compared to a control cell line which does not express GGT (V79 Cl). The cytotoxic effect was dose- and time-dependent (100% cellular death at 200 μM GS-HNE after 24 h incubation) in V79 GGT cells, whereas no decrease of viability was observed in V79 Cl cells. A similar cytotoxic effect was obtained when cells were incubated directly with CysGly-HNE, demonstrating that this GGT-dependent metabolite unlike GS-HNE, exhibits cytotoxic properties.