Effect of lipid peroxides and antioxidants on glycation of hemoglobin: An in vitro study on human erythrocytes

Background: Glycation and lipid peroxidation are two important processes known to play a key role in complications of many pathophysiological process. We sought to assess the possibility of an interaction between these processes in vitro and to examine the effect of lipoic acid and taurine on the glycation of hemoglobin and lipid peroxidation. Methods: Human erythrocytes in phosphate buffered saline (pH 7.4) were incubated with 5 or 50 mmol/l glucose. To study the effect of antioxidants on glycation of hemoglobin, erythrocytes were incubated with either lipoic acid or taurine and then exposed to glucose concentration of either 5 or 50 mmol/l. To clarify if lipid peroxides per se enhances the glycated hemoglobin level, an in vitro study was performed by incubating erythrocyte suspension containing either 5 or 50 mmol/l glucose with or without MDA. Lipid peroxides and glycated hemoglobin levels were determined in the glucose treated cells. Results: Glycated hemoglobin levels were higher in erythrocytes incubated with 50 mmol/l glucose concentrations than in erythrocytes incubated with 5 mmol/l glucose. The increase in glycated hemoglobin levels was blocked significantly when erythrocytes were pretreated with either lipoic acid or taurine. Both the antioxidants used in the present study markedly reduced the MDA levels. The level of glycated hemoglobin in erythrocyte incubated in the presence of MDA was increased significantly when compared to erythrocyte incubated with glucose alone. Conclusions: Lipid peroxides per se may have a role to play in glycation of hemoglobin and antioxidants (lipoic acid and taurine) can partially inhibit the formation of glycated hemoglobin by lowering the levels of lipid peroxides. (c) 2005 Elsevier B.V. All rights reserved.