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.

Comparison of nutritional status in hemodialysis patients with and without failed renal allografts.

BACKGROUND: The survival of patients returning to hemodialysis (HD) following kidney transplant failure is unfavorable. However, the factors responsible for this poor outcome are largely unknown; chronic inflammation due to failed allograft and malnutrition may contribute to morbidity and mortality. We aimed to compare the nutritional status and its relation with inflammation in patients on HD with and without previous kidney transplantation. METHODS: Forty-three patients with failed renal allografts (27 males; mean age 36±9 yr) and 40 never transplanted HD patients (24 males; mean age 39±9 yr) were included in the study. Body weight, triceps (TSF), biceps (BSF), subscapular (SSSF), and suprailiac skinfold thicknesses (SISF); mid-arm, mid-arm muscle, hip and waist circumferences; as well as body mass indices (BMIs) were determined as anthropometric parameters. Moreover, biochemical markers of nutritional status, including serum cholesterol and albumin as well as high-sensitive C-reactive protein (hs-CRP), as a marker of inflammation, were measured. Associations among these variables were analyzed. RESULTS: There were no significant differences considering age, gender or duration of renal replacement therapy between the two groups. The TSF (p<0.0001), BSF (p=0.005), SSSF (p=0.001), SISF (p<0.0001) skinfold thicknesses; mid-arm (p=0.003) and mid-arm muscle circumferences (p=0.037) and BMIs (p=0.001) of the patients with failed renal allografts were significantly lower than those of the never transplanted HD patients. Waist circumference was significantly lower as well (p=0.028). Patients with failed transplants were characterized by lower serum albumin (p<0.0001) and higher hs-CRP levels (p=0.001) as compared with never transplanted HD patients. CONCLUSIONS: This study confirms the concept that retained failed allografts may induce chronic inflammation in chronic HD patients which may result in a worse nutritional status.