L-arginine catabolism is driven mainly towards nitric oxide synthesis in the erythrocytes of patients with type 2 diabetes at first clinical onset

BackgroundWe investigated the l-arginine (l-Arg)–nitric oxide (NO) metabolic pathway in the erythrocytes (RBCs) and plasma of subjects with type 2 diabetes at first clinical onset.MethodsRBCs and plasma were collected from 26 patients with type 2 diabetes at first clinical onset and 19 age-matched non-diabetes subjects as controls. l-Arg content was assayed by capillary electrophoresis. We measured arginase activity and nitrate/nitrite concentrations by spectrophotometry, and glycosylated haemoglobin (HbA1c) by standardized immunoturbidimetry.ResultsWe found that, when compared with controls, l-Arg content was similar in RBCs while decreased in the plasma of patients with type 2 diabetes. Interestingly, arginase activity was lower in RBCs and increased in plasma of patients with diabetes. NO production was higher in RBCs in patients with type 2 diabetes, while no difference was found in the plasma of our subjects.Conclusionsl-Arg catabolism is driven mainly towards NO synthesis in RBCs of patients with ty...