Evaluation of oxidative stress using exhaled breath 8-isoprostane levels on chronic kidney disease.

BACKGROUND There have been limited numbers of studies on patients with chronic kidney disease (CKD) to determine oxidative stress in exhaled breath condensate (EBC). Those two studies have been carried out on hemodialysis patients, and hydrogen peroxide and nitric oxide have been studied in order to show oxidative stress on EBC. AIMS We investigated oxidative stress in EBC evaluating 8-isoprostane levels on different stages of CKD. MATERIALS AND METHODS A total of 81 patients with 2-4 CKD stages have been evaluated prospectively. The patients have been categorized into three groups according to their CKD stages. For biochemical analysis, blood and breathing air samples were taken. 8-isoprostane has been measured using immunoassay method as the indicator of oxidative stress in EBC. RESULTS 8-isoprostane values were 8.19 ± 4.56, 13.89 ± 8.70, and 14.20 ± 10.68 pg/min group 1, 2, and 3, respectively; and the EBC 8-isoprostane levels increased significantly as CKD stages advanced (P0 = 0.018). There was a statistically significant reverse correlation between 8-isoprostane and glomerular filtration rate (GFR; r = -0.275; P = 0.014), but not between 8-isoprostane and C-reactive protein (r = -0.183; P = 0.177). CONCLUSIONS We determined the level of 8-isoprostane in EBC of patients with different stages of CKD and showed that the level of 8-isoprostane significantly increased through the progress of CKD. We consider that our study is important because there have been limited number of studies that evaluate oxidative stress in CKD using EBC which is a noninvasive method.