The relationship between leptin level and oxidative status parameters in hemodialysis patients.

Both serum leptin level and oxidative stress are increased in hemodialysis (HD) patients. In the present study, we aimed to investigate whether there is association between oxidative status and leptin level in HD patients. Thirty-five HD patients and 25 healthy controls were enrolled in the present study. Serum leptin level, total peroxide (TP) level, total antioxidant capacity (TAC), and oxidative stress index (OSI) were determined. Serum leptin level, TP level, and OSI were significantly higher in HD patients than controls (all P < 0.001) while TAC was lower (P < 0.001). In HD patients, serum leptin level was significantly correlated with TP level and OSI (r = 0.372, P < 0.001 and r = 0.409, P < 0.001, respectively). The correlation of serum leptin level with TP level and OSI remained statistically significant after adjusting for age, gender, and body-fat percentage (r = 0.446, P < 0.001 and r = 0.463, P < 0.001, respectively). Hyperleptinemia seems to be associated with increased oxidative stress in HD patients, and this association may provide better understanding about the disorders related to either elevated serum leptin levels and/or increased oxidative stress in HD patients.

PON1 status in haemodialysis patients and the impact of hepatitis C infection.

OBJECTIVES: Paraoxonase-1 (PON1) activity has been reported to decrease in both haemodialysis patients and patients with HCV infection. We aimed to investigate paraoxonase and arylesterase activities, and lipid hydroperoxide levels (LOOH) in haemodialysis patients with or without hepatitis C infection, and to find out whether PON1 activity is affected further by the presence of HCV infection in HD patients. DESIGN AND METHODS: Twenty HCV (+) haemodialysis patients, 26 HCV (-) haemodialysis patients, and 26 controls were enrolled. Paraoxonase and arylesterase activities were measured spectrophotometrically. LOOH levels were measured by ferrous oxidation with xylenol orange assay. RESULTS: Haemodialysis patients with or without HCV infection had lower paraoxonase and arylesterase activities than controls (all p<0.001), while higher LOOH levels (both p<0.001). Paraoxonase and arylesterase activities, and LOOH levels were comparable between haemodialysis patients with or without HCV infection (p>0.05). Significant inverse correlation was observed between paraoxonase or arylesterase activities, and LOOH levels (p<0.05, beta=-0.319 and p<0.05, beta=-0.348, respectively). CONCLUSION: We concluded that PON1 activity significantly decreases in both haemodialysis patients with or without HCV infection. Nevertheless, PON1 activity is not affected further by the presence of HCV infection in haemodialysis patients.

The association of circulating leptin level with peripheral DNA damage in hemodialysis subjects.

OBJECTIVES: Hemodialysis subjects have been shown to have both elevated serum leptin and peripheral DNA damage level, and leptin has been suggested to induce apoptotic features. Thus, in the present study, we aimed at finding out if there is any relationship between serum leptin level and peripheral DNA damage in hemodialysis subjects. DESIGN AND METHODS: Forty hemodialysis subjects and 21 controls were included in the present study. Serum leptin level and peripheral DNA damage were assayed in all subjects enrolled in the study. Comet assay was used in determining DNA damage in peripheral lymphocyte. RESULTS: Both serum leptin level and peripheral DNA damage were significantly higher in hemodialysis subjects than control (P<0.05 and P<0.001, respectively). Female subjects had significantly higher serum leptin level than male subjects in both hemodialysis and control group (both P<0.05). Significant correlation was observed between serum leptin level, and gender and body fat mass in both hemodialysis (P<0.05, beta=-0.637 and P<0.05, beta=0.386, respectively) and control group (P<0.05, beta=-0.569 and P<0.05, beta=-0.460, respectively). In hemodialysis subjects, peripheral DNA damage was significantly correlated with serum leptin level (P<0.05, beta=0.508). CONCLUSION: In end-stage renal disease subjects, elevated serum leptin level seems to be associated with peripheral DNA damage and thus, may, in part, have a role in the development of DNA damage associated disorders.

Oxidative stress in hepatitis C infected end-stage renal disease subjects.

BACKGROUND: Both uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects. METHODS: Sixteen hepatitis C (+) hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects. RESULTS: Total antioxidant capacity was significantly higher in controls than hemodialysis subjects with or without hepatitis C infection (all p < 0.05/3), while total peroxide level and oxidative stress index were significantly lower (all p < 0.05/3). Hepatitis C (-) hemodialysis subjects had higher total antioxidant capacity compared to hepatitis C (+) hemodialysis subjects (all p < 0.05/3). Total peroxide level and oxidative stress index was comparable between hemodialysis subjects with or without hepatitis C infection (p > 0.05/3). CONCLUSION: Oxidative stress is increased in both hepatitis C (+) and hepatitis C (-) hemodialysis subjects. However, hepatitis C infection seems to not cause any additional increase in oxidative stress in hemodialysis subjects and it may be partly due to protective effect of dialysis treatment on hepatitis C infection.

Assessment of peripheral DNA damage by alkaline comet assay in maintenance hemodialysis subjects with hepatitis C infection.

Despite the high prevalence of hepatitis C infection among hemodialysis subjects, there is no information concerning the DNA damage of hepatitis C (+) hemodialysis subjects. We aimed to find out if there is any additional effect of hepatitis C infection on peripheral DNA damage in maintenance hemodialysis subjects. Fifteen hepatitis C (+) and 22 hepatitis C (-) hemodialysis subjects, 21 hepatitis C subjects without renal disease, and 22 healthy controls were enrolled. Peripheral DNA damage was assayed using alkaline comet assay. Median DNA damage levels of the study groups were as follows: hepatitis C (+) maintenance hemodialysis subjects, 88 (0-232); hepatitis C (-) maintenance hemodialysis subjects, 58 (0-228); hepatitis C (+) subjects without renal disease, 112 (44-252); controls, 26 (0-72). DNA damage level was significantly higher among hepatitis C (+) subjects without renal disease than hepatitis C (-) maintenance hemodialysis subjects and healthy controls (both p<0.05/6). Both maintenance hemodialysis subjects with and without HCV infection had significantly higher DNA damage level than healthy controls (both p<0.05/6). DNA damage level was comparable between hepatitis C (+) subjects without renal disease and HCV (+) hemodialysis subjects, and between hemodialysis subjects with and without hepatitis C infection (all p>0.05/6). Linear regression analysis revealed that hepatitis C infection was the only independent factor in predicting the peripheral DNA damage (p<0.05, beta=0.395). Each one of end-stage renal disease and hepatitis C infection significantly increases DNA damage level. However, in hemodialysis subjects, hepatitis C infection does not cause significant additional increase in DNA damage level, and it may be partly due to protective effect of hemodialysis on hepatitis C infection.