Oxidative Stress in Uremic Children and its Relation to Hemoglobin Levels and Left Ventricular Hypertrophy.

ABSTRACT
Background: Cardiovascular diseases (CVD) represents the major cause of mortality in hemodialysis patients. Several factors are supposed to be responsible for that increase in cardiovascular risks. Oxidative stress has been postulated to be an important risk factor for CVD . Oxygen free radicals and their secondary products, together called reactive oxygen species (ROS) ,exert angiotoxic and cardiotoxic effects. Objectives: To evaluated serum levels of lipid peroxidation (LPO) products, 4-hydroxynonenal (HNE) and malondiahdhyde (MDA), as indicators of oxidative stress in children with chronic renal failure (CRF) before and after dialysis and their relation to hemoglobin (Hb) level and left ventricular hypertrophy (LVH). Methods: This cross-sectional study included 20 children (8 males and 12 females) suffering from CRF on conservative therapy only without taking erythropoietin (non-dialyzed group) and 20 children 8 males and 12 females) suffering from CRF on regular hemodialysis and erythropoietin (EPO) therapy for at least 6 months (dialyzed group). Their ages ranged from 4 to 16 years. 20 healthy children of comparable age and sex were taken as a control group. Measurement of MDA and HNE as markers of lipid peroxidation (LPO) was performed by using spectrophotometry and high performance liquid chromatography, respectively. Echocardiography was done for all subjects as well. Results: There was an increase in LPO products (HNE & MDA) in CRF patients compared with control subjects. However, HNE only was significantly higher in group I (non-dialyzed) than group II (dialyzed); 353.27 ± 55.5 vs. 346.7 ± 58.8, p < 0.01; while MDA levels in both group I and group II showed non-significant difference; 4.4 ± 1.6 vs. 4.3 ± 1.3, p > 0.05. Hemoglobin levels were significant lower in CRF patients than control subjects, but Hb was non-significantly higher in group II (dialyzed) than group I (non-dialyzed); 8.7 g/dl ± 2.5vs. 8.2 ± 2.3, p < 0.05. Left ventricular mass index (LVMI) was significantly higher in CRF patients than control subjects. However, LVMI was significantly higher in group II (dialyzed) than group I (non-dialyzed); 118.1 ± 5.15, p < 0.05, LVMI, HNE and MDA were all higher in CRF patients with Hb levels less than 9.5 gm/dl than those with Hb levels higher than 9.5 gm/dl. A significant negative correlation was found between Hb levels and LPO (HNE & MDA) as well as LVMI; r = -0.75, -0.81, -0.65; respectively. A significant positive correlation was found between LPO products (HNE & MDA) and LVMI; r = 0.54, 0.41, respectively. Conclusions: Oxidative stress and lipid peroxidation represent a major health problem in CRF patients. Optimized correction of anemia as well as regular efficient dialysis help reduce oxidative stress including lipid peroxidation thereby reducing cardiovascular morbidity in patients with CRF, thus improving their quality of life and improving the prognosis of renal failure.