Oxidants and antioxidants in long-term haemodialysis patients

Biomonitoring of Oxidative-Stress-Related Genotoxic Damage in Patients with End-Stage Renal Disease

Chronic kidney disease (CKD), a common progressive renal failure characterized by the permanent loss of functional nephrons can rapidly progress to end-stage renal disease, which is known to be an irreversible renal failure. In the therapy of ESRD, there are controversial suggestions about the use of regular dialysis, since it is claimed to increase oxidative stress, which may increase mortality in patients. In ESRD, oxidative-stress-related DNA damage is expected to occur, along with increased inflammation. Many factors, including heavy metals, have been suggested to exacerbate the damage in kidneys; therefore, it is important to reveal the relationship between these factors in ESRD patients. There are very few studies showing the role of oxidative-stress-related genotoxic events in the progression of ESRD patients. Within the scope of this study, genotoxic damage was evaluated using the comet assay and 8-OHdG measurement in patients with ESRD who were undergoing hemodialysis. The biochemical changes, the levels of heavy metals (aluminum, arsenic, cadmium, lead, and mercury) in the blood, and the oxidative biomarkers, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were evaluated, and their relationship with genotoxic damages was revealed. Genotoxicity, oxidative stress, and heavy-metal levels, except mercury, increased significantly in all renal patients. DNA damage, 8OHdG, and MDA significantly increased, and GSH significantly decreased in patients undergoing dialysis, compared with those not having dialysis. The duration and the severity of disease was positively correlated with increased aluminum levels and moderate positively correlated with increased DNA damage and cadmium levels. In conclusion, this study revealed that the oxidative-stress-related DNA damage, and also the levels of Al and Cd, increased in ESRD patients. It is assumed that these changes may play an important role in the progression of renal damage. Approaches for reducing oxidative-stress-related DNA damage and heavy-metal load in ESRD patients are recommended.

Hemodializ Hastalarında Sistatin C Düzeyleri, Oksidan-Antioksidan ve İnflamasyon Durumu

Objective: Cystatin C is considered an important marker for the detection of renal dysfunction. It was aimed to determine cystatin C levels, status of oxidant-antioxidant and inflammation in hemodialysis (HD) patients. Methods: The study groups consisted of 20 HD patients and 20 healthy controls. Blood samples were obtained from the control group and from the HD group before hemodialysis. Serum cystatin C, total antioxidant capacity (TAC), total oxidative state (TOS), tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) interleukin 18 (IL-18) levels were detected by Enzyme Linked Immunosorbent Assay (ELISA), C-reactive protein (CRP) and some biochemical parameters were analyzed by autoanalyser. Results: Cystatin C, TOS, TNF-α, IL-6, IL-18 and CRP levels of the HD group were significantly higher than the control group. Conclusion: As a result; oxidative stress and inflammation were increased in patients with chronic renal failure undergoing hemodialysis. New strategies and new studies are needed to reduce the increase in oxidative stress and inflammation in HD patients.

Oxidative Stress Markers in Chronic Kidney Disease with Emphasis on Diabetic Nephropathy

Diabetes prevalence is increasing worldwide, especially through the increase of type 2 diabetes. Diabetic nephropathy occurs in up to 40% of diabetic patients and is the leading cause of end-stage renal disease. Various factors affect the development and progression of diabetic nephropathy. Hyperglycaemia increases free radical production, resulting in oxidative stress, which plays an important role in the pathogenesis of diabetic nephropathy. Free radicals have a short half-life and are difficult to measure. In contrast, oxidation products, including lipid peroxidation, protein oxidation, and nucleic acid oxidation, have longer lifetimes and are used to evaluate oxidative stress. In recent years, different oxidative stress biomarkers associated with diabetic nephropathy have been found. This review summarises current evidence of oxidative stress biomarkers in patients with diabetic nephropathy. Although some of them are promising, they cannot replace currently used clinical biomarkers (eGFR, proteinuria) in the development and progression of diabetic nephropathy.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin–angiotensin–aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water–electrolyte and acid–base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

Determination of oxidative stress and cellular inflammation in patients with diabetic nephropathy and non-diabetic nephropathy being administered hemodialysis treatment due to chronic renal failure

OBJECTIVES

We aimed to evaluate oxidative stress [8-hydroxydeoxyguanosine (8-OHdG), malondialdehyde (MDA)] endothelial damage [asymmetric dimethylarginine (ADMA)] and markers of cellular inflammation [interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), neopterin (NP) and high-sensitivity C-reactive protein (hsCRP)] in patients with diabetic nephropathy (DN) and non-diabetic nephropathy who were being administered hemodialysis treatment because of chronic renal failure.

METHODS

In determining 8-OHdG, IL-6 and TNF-α levels, Enzyme-Linked Immuno-Sorbent Assay method was used. Serum MDA, ADMA and NP levels were determined by using high performance liquid chromatography (HPLC). And hs-CRP values were measured with nephelometric method.

RESULTS

Serum 8-OHdG and MDA levels were found statistically to have increased when compared with those of the control group in patients groups after dialysis. However, serum ADMA and neopterin levels were observed statistically to have decreased when compared with those of the control group in patients groups after dialysis. But, decreases on ADMA and neopterin levels are still much higher than those of control. IL-6 and TNF-α levels were found to have increased when compared with those of control group in patients groups before dialysis.

CONCLUSION

The oxidative stress in patients with DN, who were being treated with hemodialysis due to chronic renal failure, was higher than that of non-DN patients who were being treated with hemodialysis. In contrast with this, inflammation occurring in non-DN patients was found to have been higher than that of in patients with DN.

Clinical and research markers of oxidative stress in chronic kidney disease

CONTEXT

Kidney-related pathologies have increasing prevalence rates, produce a considerable financial burden, and are characterized by elevated levels of oxidative stress (OS).

OBJECTIVE

This review examines relationships between chronic kidney disease (CKD) and markers of OS and antioxidant status (AS).

METHODS

A systematic review of MEDLINE-indexed clinical trials, randomized controlled trials and comparative studies that examined OS and AS was performed.

RESULTS AND CONCLUSION

Several markers emerged as well-suited indicators of OS and AS in CKD: malondialdehyde, F2-isoprostanes, lipid hydroperoxides, asymmetric dimethylarginine, 8-oxo-7,8-dihydro-2'-deoxyguanosine, protein carbonyls, advanced oxidation protein products and glutathione-related activity.

Hypoxia and oxidative stress markers in pediatric patients undergoing hemodialysis: cross section study

Background

Tissue injury due to hypoxia and/or free radicals is common in a variety of disease processes. This cross-sectional study aimed to investigate effect of chronic kidney diseases (CKD) and hemodialysis (HD) on hypoxia and oxidative stress biomarkers.

Methods

Forty pediatric patients with CKD on HD and 20 healthy children were recruited. Plasma hypoxia induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) were measured by specific ELISA kits while, total antioxidant capacity (TAC), total peroxide (TPX), pyruvate and lactate by enzymatic/chemical colorimetric methods. Oxidative stress index (OSI) and lactate/pyruvate (L/P) ratio were calculated.

Results

TAC was significantly lower while TPX, OSI and VEGF were higher in patients at before- and after-dialysis session than controls. Lactate and HIF-1α levels were significantly higher at before-dialysis session than controls. Before dialysis, TAC and L/P ratio were lower than after-dialysis. In before-dialysis session, VEGF correlated positively with pyruvate, HIF-1α and OSI correlated positively with TPX, but, negatively with TAC. In after-dialysis session, HIF-1α correlated negatively with TPX and OSI; while, OSI correlated positively with TPX.

Conclusions

CKD patients succumb considerable tissue hypoxia with oxidative stress. Hemodialysis ameliorated hypoxia but lowered antioxidants as evidenced by decreased levels of HIF-1α and TAC at before- compared to after-dialysis levels.

Comparison of the oxidant-antioxidant parameters and sialic acid levels in renal transplant patients and peritoneal dialysis patients

OBJECTIVE

Several studies have shown that in end-stage renal failure, increased oxidative stress and reduced antioxidant system functions may play an important role in inflammation, atherosclerosis, and many other complications. Paraoxonase (PON) and arylesterase (ARE) are antioxidant and malondialdehyde (MDA) an oxidant agent. Increased sialic acid (SyA) levels in uremic patients is an acute-phase response showing tissue and organ damage. The aim of this study was to compare PON, ARE, MDA, and SyA among continuous ambulatory peritoneal dialysis (CAPD) and renal transplant patients.

METHODS

Twenty-six CAPD patients including 7 women and 19 men of overall mean age 40.5 ± 10.66 years were included in this study. There were 28 preemptive transplant patients, namely 6 women and 22 men of overall mean age 36.5 ± 10.97 years. CAPD was the initial sole replacement therapy. Serum PON, ATE, MDA, and SyA levels were measured at 13-15 months of treatment.

RESULTS

Higher PON (P = .015) and ARE (P = .002) and lower MDA (P = .002) and SyA (P = .000) values were determined among transplanted compared with CAPD patients.

CONCLUSIONS

In the transplant group, antioxidant parameters were higher and oxidant parameters lower with less activation of SyA than in the CAPD group. We observed that renal transplantation had a constructive effect on the oxidant-antioxidant system and consequent tissue destruction, which were impaired in uremic subjects. This study showed that renal transplantation is a more appropriate replacement treatment than CAPD.

The effects of 1-year treatment with a haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) dialysis on biomarkers of oxidative stress in patients with chronic renal failure

In the last few years haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) has been shown to have a positive impact on inflammation and oxidative stress biomarkers, but its effect on antioxidant levels and on oxidative damage to biomolecules in the long-term is still unknown. This is a randomised clinical study over 12 months involving 40 patients on haemodialysis, comparing the effect of HFR (n=25) dialysis with haemodialysis with polysulfone (HD-PS, n=15) on oxidative stress. Total antioxidant capacity, enzymatic antioxidant [superoxide dismutase (SOD), catalase and glutathione peroxidase], non-enzymatic (GSH) and biomarkers of oxidative stress (TBARs, carbonyl groups and 8-OH-dG) were evaluated. The antioxidant activity decreased in the lymphocytes of patients dialysed with HFR, with a significant decrease in the enzyme SOD. In the oxidative stress biomarkers, an increase was seen in the levels of 8-OH-dG in patients on HD-PS dialysis but not in those treated with HFR. Throughout the year the changes in antioxidant levels and biomarkers of oxidative damage in patients dialysed with HFR were generally more modest and fluctuated less than those dialysed with HD-PS. Our study indicates that, in general, long-term dialysis with HFR does not modified antioxidant parameters or increases the oxidative damage to biomolecules. The HFR showed to be a biocompatible technique for long-term dialysis.

Hemodialysis alters lipid profiles, total antioxidant capacity, and vitamins A, E, and C concentrations in humans

Although hemodialysis (HD) is essential for end-stage renal disease patients, at the same time it causes oxidative stress and long-term pro-atherosclerotic effects. This study aimed to determine lipid profile as well as the total antioxidant capacity (TAC) and vitamins A, E, and C in HD patients. The study enrolled 31 patients (50.3 ± 14.9 years old) undergoing maintenance 4-hour HD three times per week with a polysulfone membrane dialyzer for a mean of 76.1 months (range, 7-120 months) and 31 healthy individuals (47.8 ± 13.9 years old). Lipid profiles were determined spectrophotometrically using commercially available kits. Total antioxidant capacity was determined by ferric reducing/antioxidant power assay, levels of vitamins A and E were assayed using high-pressure liquid chromatography, and the level of vitamin C was measured by a photometric method. Our results showed that before HD, the levels of TAC and vitamin A were significantly higher than in normal subjects, whereas the levels of high-density lipoprotein (HDL) and vitamin C were lower than in control subjects (P < .001). There was no significant difference between normal subjects and patients before dialysis regarding low-density lipoprotein (LDL) and vitamin E levels (P > .05). After HD, the levels of HDL-cholesterol, vitamins E and C, and TAC decreased significantly (P < .001), but the decreased level of vitamin A still remained higher than controls (P < .05), whereas the levels of LDL were significantly higher than controls (P < .001). In conclusion, alterations in the lipoprotein profiles and antioxidant markers following HD suggest an increased risk of atherosclerosis in these patients.

Considerations in the statistical analysis of hemodialysis patient survival

The association of hemodialysis dosage with patient survival is controversial. Here, we tested the hypothesis that methods for survival analysis may influence conclusions regarding dialysis dosage and mortality. We analyzed all-cause mortality by proportional hazards and accelerated failure time regression models in a cohort of incident hemodialysis patients who were followed for 9 yr. Both models identified age, race, heart failure, physical functioning, and comorbidity scores as important predictors of patient survival. Using proportional hazards, there was no statistically significant association between mortality and Kt/V (hazard ratio 0.72; 95% confidence interval 0.45 to 1.14). In contrast, using accelerated failure time models, each 0.1-U increment of Kt/V improved adjusted median patient survival by 3.50% (95% confidence interval 0.20 to 7.08%). Proportional hazard models also yielded less accurate estimates for median survival. These findings are consistent with an additive damage model for the survival of patients who are on hemodialysis. In this conceptual model, the assumptions of the proportional hazard model are violated, leading to underestimation of the importance of dialysis dosage. These results suggest that future studies of dialysis adequacy should consider this additive damage model when selecting methods for survival analysis. Accelerated failure time models may be useful adjuncts to the Cox model when studying outcomes of dialysis patients.

Effect of one-year oral alpha-tocopherol administration on the antioxidant defense system in hemodialysis patients

Oxidative stress is increased in hemodialysis (HD) patients and contributes to the increased morbidity and mortality in this population. Vitamin E is an antioxidant agent. In the present study the effect of prolonged oral alpha-tocopherol administration on the antioxidant defense system was evaluated. The antioxidant factors plasma total antioxidant status (TAS), red blood cell superoxide dismutase (SOD) activity and glutathione peroxidase (GPX) activity were evaluated with spectrometry in 27 HD patients. Measurements were performed before and after oral administration of alpha-tocopherol at a dose of 500 mg/d for a one-year period. Twenty HD patients received a placebo and 22 healthy volunteers served as controls. TAS was increased in HD patients. No difference was detected in SOD and GPX activity between HD patients and healthy volunteers. Tocopherol administration induced a significant decrease in TAS and SOD activity. Levels of GPX activity remained unaffected. All the evaluated factors remained stable in the HD patients receiving a placebo. Prolonged oral alpha-tocopherol administration in HD patients induces a decrease in some components of the antioxidant defense system, raising the possibility for a pro-oxidative role of vitamin E. Vitamin E is an antioxidant agent, but it is also known to have pro-oxidant action under special conditions that can be encountered in HD patients.

Role of plasma protein and low-molecular weight substances in the change of hydroxyl radical scavenging activity in hemodialysis patients

While it is well known that hemodialysis (HD) patients with end stage renal failure are exposed to high oxidative stress, there is not a general opinion regarding whether antioxidant activity is high or low in these patients. We evaluated the variation of plasma hydroxyl radical scavenging activity (p-HRSA) by a single-session of HD in 69 patients by using a new system, reactive flow-injection electron spin resonance. And then comparing p-HRSA with their biochemical parameters, we tried to elucidate what components affected p-HRSA in the HD patients. The average of p-HRSA significantly increased after HD and the variation of p-HRSA by HD was correlated with that of plasma total protein (TP). In 5 patients however, their p-HRSA decreased after HD, in spite of increasing TP. In pre-HD, the p-HRSA values and hydroxyl radical scavenging activity of low-molecular weight fraction of plasma were significantly higher in these 5 patients than in patients whose p-HRSA increased after HD. These 5 patients were in an inflammatory state. These findings suggest that p-HRSA is mainly affected by TP, but caution should be exercised in patients who have high p-HRSA before HD and whose p-HRSA does not increase after HD.

Effect of nandrolone decanonate on paraoxonase activity in hemodialysis patients

OBJECTIVES

This study was designed to determine the effect of nandrolone decanonate (ND) on HDL-C, apolipoproteins and paraoxonase (PON) activity in stable hemodialysis patients.

DESIGN AND METHODS

64 hemodialysis patients were treated with ND at a dose of 100 mg/I.M./week for 4 months. HDL-C, Apo-AI, Apo B, concentrations and PON activity were measured before and after 2 and 4 months of treatment as well as 2 months after withdrawing the treatment.

RESULTS

After 4 months of treatment, an elevation in the serum levels of Apo B (P<0.0001) and a marked decrease in the concentration of HDL-C (P<0.0001), Apo-AI (P<0.0001) and PON activity (P<0.0001) were found. A significant correlation between PON and both Apo-AI (r=0.270, P<0.04) and HDL-C (r=0.455, P<0.0001) and also between HDL-C and Apo-AI (r=0.305, P<0.02) were found.

CONCLUSION

Results revealed the adverse effects of ND on apolipoprotein levels in our study population. It is possible that ND reduces PON activity mostly by reducing both the HDL-C and Apo-AI levels.

The effects of Pycnogenol on DNA damage in vitro and expression of superoxide dismutase and HP1 in Escherichia coli SOD and catalase deficient mutant cells

The procyanidin-rich French maritime pine bark extract Pycnogenol (PYC) is believed to be an antioxidant. To access whether PYC protects DNA against Fenton reaction radicals, pUC 19 plasmid DNA was damaged by OH- radicals generated from Fe(II) plus H2O2 in the presence and absence of PYC. DNA damage was quantified by measuring decreases in supercoiled DNA (SC-DNA) using agarose gel electrophoresis. The results showed that PYC (50 microg/mL) did not inhibit DNA damage from Fenton reaction-generated oxyradicals, when the Fenton reaction was allowed to proceed. However, PYC did protect against DNA damage when added prior to the initiation of the Fenton reaction, suggesting that protection resulted from chelation of Fe rather than from the scavenging of radicals. Moreover, we unexpectedly observed PYC-associated DNA breakage, which was dose- and time- dependent. Other antioxidants such as desferrioxamine (DFO) including butylated hydroxyltoluene (BHT), curcumin and alpha-tocopherol exhibited protective effects against DNA damage caused by the Fenton reaction. Subsequently, we assessed the possible pro-oxidant function of PYC on DNA damage in E. coli SOD deficient mutants under oxidative stress, after observing that PYC can induce SOD under oxidative stress. Although, PYC did not enhance DNA damage, it likewise did not protect against oxidative stress-mediated DNA damage. All together, our data indicate that PYC under some circumstances can enhance oxidative stress-mediated DNA damage in vitro and in vivo.

Lycopene from two food sources does not affect antioxidant or cholesterol status of middle-aged adults

Background

Epidemiological studies have reported associations between reduced cardiovascular disease and diets rich in tomato and/or lycopene. Intervention studies have shown that lycopene-containing foods may reduce cholesterol levels and lipid peroxidation, factors implicated in the initiation of cardiovascular disease. The objective of this study was to determine whether consumption of lycopene rich foods conferred cardiovascular protection to middle-aged adults as indicated by plasma lipid concentrations and measures of ex vivo antioxidants.

Methods

Ten healthy men and women consumed a low lycopene diet with no added lycopene (control treatment) or supplemented with watermelon or tomato juice each containing 20 mg lycopene. Subjects consumed each treatment for three weeks in a crossover design. Plasma, collected weekly was analyzed for total cholesterol, high density lipoprotein cholesterol (HDL-C) and triglyceride concentrations and for the antioxidant biomarkers of malondialdehyde formation products (MDA), plasma glutathione peroxidase (GPX) and ferric reducing ability of plasma (FRAP). Data were analyzed using Proc Mixed Procedure and associations between antioxidant and lipid measures were identified by Pearson's product moment correlation analysis.

Results

Compared to the control diet, the lycopene-containing foods did not affect plasma lipid concentrations or antioxidant biomarkers. Women had higher total cholesterol, HDL-C and triglyceride concentrations than did the men. Total cholesterol was positively correlated to MDA and FRAP while HDL-C was positively correlated to MDA and GPX. GPX was negatively correlated to triglyceride concentration.

Conclusions

The inclusion of watermelon or tomato juice containing 20 mg lycopene did not affect plasma lipid concentrations or antioxidant status of healthy subjects. However, plasma cholesterol levels impacted the results of MDA and FRAP antioxidant tests.

Identification of hepatic molecular mechanisms of action of alpha-tocopherol using global gene expression profile analysis in rats

The recent discovery that vitamin E (VE) regulates gene activity at the transcriptional level indicates that VE may exert part of its biological effects by mechanisms which may be independent of its well-recognised antioxidant function. The objective of this study was the identification of hepatic vitamin E-sensitive genes and examination of the effects of VE on their corresponding biological endpoints. Two groups of male rats were randomly assigned to either a VE-sufficient diet or to a control diet deficient in VE for 290 days. High-density oligonucleotide microarrays comprising over 7000 genes were used to assess the transcriptional response of the liver. Differential gene expression was monitored over a period of 9 months, at four different time-points, and rats were individually profiled. This experimental strategy identified several VE-sensitive genes, which were chronically altered by dietary VE. VE supplementation down-regulated scavenger receptor CD36, coagulation factor IX and 5-alpha-steroid reductase type 1 mRNA levels while hepatic gamma glutamyl-cysteinyl synthetase was significantly up-regulated. Measurement of the corresponding biological endpoints such as activated partial thromboplastin time, plasma dihydrotestosterone and hepatic glutathione substantiated the gene chip data which indicated that dietary VE plays an important role in a range of metabolic processes within the liver.

Effect of Lovastatin on lipid peroxidation and total antioxidant concentrations in hemodialysis patients

BACKGROUND

Atherosclerosis is the main cause of mortality and morbidity in end stage renal diseases (ESRD), especially in hemodialysis (HD) patients. In addition the classic risk factors for atherosclerosis, non classical risk factors, such as high lipid peroxidation and low antioxidants, also, are culprit in the pathogenesis.

METHOD

We tested lipid peroxidation and total antioxidant levels in forty five stable hyperlipidemic HD males (age range 40-60 years) before, after 45 and 90 days of prescription of 20 mg/day Lovastatin for three months. Malondialdehyde (MDA), as prototype of lipid peroxidation, and total antioxidants (TA) were measured by flourimetric and spectrophotometric assays, respectively.

RESULTS

Serum triglyceride (Tg) (213.7 +/- 112.4 mg/dl vs. 153.4 +/- 54.8 mg/dl p = 0.003), serum cholesterol (C) (185.8 +/- 48.3 mg/dl vs. 149.3 +/- 37.8 mg/dl, p = 0.014), LDL-C (120.1 mg/dl +/- 48.9 vs. 84.8 +/- 43.7 mg/d, p = 0.001), VLDL-C (40.7 +/- 18.9 mg/dl vs. 30.7 +/- 10.9 mg/dl, p = 0.025), MDA (13.1 +/- 3.5 nmol/ml vs. 1.27 +/- 1 nmol/ml, p = 0.00), TA (0.98 +/- 0.17 mmol/l vs. 1.28 +/- 0.27 mmol/l, p = 0.001) and HDL (24.9+11.1 mg/dl vs. 31.4 +/- 7.7 mg/dl, p = 0.007) significantly were changed by 3 months of Lovastatin therapy. These changes for HDL, VLDL and Tg after the 3 months were more obvious than 45 days of Lovastatin therapy.

CONCLUSION

In HD patients serum lipids and their oxidations are increased. Both of them, quantitatively and qualitatively, are improved by using of Lovastatin. The later would be due to enhance of TA activity.

Dyslipidemia, oxidative stress and cardiac dysfunction in children with chronic renal failure: effects of L-carnitine supplementation

BACKGROUND

Secondary carnitine deficiency may develop in chronic renal failure (CRF) patients undergoing long-term hemodialysis (HD), with a resulting higher incidence of cardiovascular diseases, dyslipidemia and oxidative stress. We studied the efficacy of 12 months of L-carnitine supplementation on the amelioration of dyslipidemia, oxidative stress and cardiac dysfunction in 24 CRF children undergoing long-term HD compared with 24 age- and sex-matched controls.

METHODS

Plasma samples were analyzed spectrophotometerically before and after dialysis sessions and after 2-month supplementation with oral L-carnitine (50 mg/kg/day) for free carnitine (FC), the lipid profile, and oxidative stress markers. Echocardiography the day following dialysis measured cardiac diameters, wall thicknesses, left ventricular mass index (MI), end diastole and systole volume indices and functions.

RESULTS

The pre-dialysis FC concentration was substantially lower than controls and decreased significantly at the end of the dialysis session. Pre- and post-dialysis plasma levels of free fatty acids (FFAs), trigyleride (TG), total cholesterol (TC) and oxidative stress markers significantly increased while high-density lipoprotein cholesterol (HDL-C) and phospholipids significantly decreased compared to controls. Echocardiography detected a significant increase in cardiac diameters and thickness, and systolic and diastolic cardiac dysfunction. After L-carnitine supplementation, plasma levels of FC increased to normal levels. FFAs, TC and HDL-C returned to control levels while TG, phospholipids, and the oxidative stress markers decreased but remained significantly higher than controls. There was a significant decrease in cardiac diameters and an increase in left ventricular diastolic function (E/A ratio), but no correlation between FC levels and echocardiographic parameters. Pre-dialysis, post-dialysis and after treatment, plasma FC level showed a significant positive correlation with HDL-C and phospholipids and a significant negative correlation with each of oxidative stress markers, FFAs, TG and TC. On the other hand, FFAs showed a significant positive correlation with TG, TC, DC, NO and a significant negative correlation with HDL-C and phospholipids.

CONCLUSION

This study demonstrates that CRF children under regular HD suffer from a decrease in the level of plasma FC, dyslipidemia, oxidative stress, and an increase in cardiac diameters and thickness with impairment of cardiac functions. Oral L-carnitine supplementation at a dose of 50 mg/kg for 2 months can increase plasma FC level, improve dyslipidemia, decrease oxidative stress with reduction of cardiac diameters and increase in diastolic function.

Congestive heart failure in patients with chronic kidney disease and on dialysis

CHF is highly prevalent in ESRD and is a leading cause of death in such patients. Hypertension, renal anemia, and comorbid conditions such as coronary artery disease are particularly important risk factors for CHF in ESRD. Dialysis hypotension may be a marker of poor prognosis in such persons. Recent studies suggest that lipid peroxidation and L-carnitine deficiency may contribute to CHF in some patients with ESRD. All forms of renal replacement therapy are capable of ameliorating symptoms of CHF, but their effect on cardiovascular mortality has not been firmly established. Drug therapy, particularly angiotensin-converting enzyme inhibitors and beta-adrenergic receptor blockers, is under-used in patients with ESRD and CHF. Heart/kidney transplantation may be a viable option for some patients with advanced CHF and ESRD.