Hyperketonemia can increase lipid peroxidation and lower glutathione levels in human erythrocytes in vitro and in type 1 diabetic patients

Recent studies have suggested that elevated cellular lipid peroxidation may play a role in the development of cellular dysfunction and other complications of diabetes. People with type 1 diabetes frequently encounter elevated levels of the ketone bodies acetoacetate (AA), beta-hydroxybutyrate (BHB), and acetone (ACE). This study was undertaken to test the hypothesis that ketosis might increase lipid peroxidation and lower glutathione (GSH) levels of red blood cells (RBCs) in diabetic patients. This study demonstrates that incubation of AA with normal RBCs in phosphate-buffered saline (37 degrees C for 24 h) resulted in marked GSH depletion, oxidized glutathione accumulation, hydroxyl radical generation, and in-creased membrane lipid peroxidation. Increases in oxygen radicals and lipid peroxidation and depletion of GSH in RBCs were not observed with BHB or ACE treatments. Similarly, there was a significant generation of superoxide ion radicals even in a cell-free buffer solution of AA, but not in that of BHB. The presence of BHB together with AA. did not influence the capacity of AA to generate oxygen radicals in a cell-free solution or the increase in lipid peroxidation of RBCs incubated with AA. The antioxidants vitamin E and N-acetylcysteine (NAC) blocked increase in lipid peroxidation in AA-treated RBCs. To examine the effects of ketone bodies in vivo, studies were performed that showed a significant decrease in GSH and an increase in lipid peroxidation levels in RBCs of hyperketonemic diabetic patients, but not in normoketonemic type 1 diabetic patients, when compared with age-matched normal subjects. This study demonstrates that elevated levels of the ketone body AA. can increase lipid peroxidation and lower GSH levels of RBCs in people with type 1 diabetes.