RESUMO
INTRODUCTION: Type 1 diabetes is an insulin deficiency-based chronic disease. It leads to the development of hyperglycaemia, which plays a key role in the initiation and progression of tissue damage in patients with diabetes. This mostly results from oxidative stress, whose increased severity is observed in this group of patients. Increased levels of 8-isoprostanes are seen in many inflammatory diseases, including asthma, COPD and cystic fibrosis. These diseases demonstrated the usefulness of the exhaled breath condensate (EBC) for extracting material for markers of oxidative stress, including 8-isoprostanes. The purpose of this study was to assess the severity of oxidative stress measured with 8-isoprostane concentrations in the exhaled breath condensate in healthy subjects and in patients with type 1 diabetes with and without vascular complications. MATERIAL AND METHODS: 33 patients assigned to the control group, type 1 diabetes without complications group and type 1 diabetes group with advanced complications were included in the study. Retinopathy, nephropathy or neuropathy have been reported as a criterion distinguishing between complicated and uncomplicated diabetes. EBC was obtained for each subject. 8-isoprostane concentrations were determined in serum and EBC by ELISA. RESULTS AND CONCLUSIONS: Mean (± SD) blood levels of 8-isoprostane in patients with type 1 diabetes mellitus without complications and those with type 1 diabetes with advanced complications were significantly higher compared to the control group (178.17 [135.73] vs. 183.34 [200.41] vs. 47.13 [25.20] pg/ml; p < 0.05). The mean (± SD) concentration of 8-isoprostane in EBC was lower in diabetic patients with type 1 diabetes with advanced complications than in patients with type 1 diabetes without advanced complications and in the control group (8.32 [4.60] vs. 19.13 [22.35] vs. 28.17 [35.11] pg/ml; p < 0.05). Measurement of 8-isoprostanes in the EBC in patients with type 1 diabetes does not appear to be a good diagnostic tool for monitoring the activity of oxidative stress in these patients.
