4-hydroxy-2-nonenal and Kidney-Failure--Chronic

Uremic syndrome is associated with several metabolic disturbances. Oxidative stress is an important factor involved in the pathologic mechanism of these changes. The goal of this study was to understand the relationship between oxidative stress markers and two compounds included among uremic toxins. Two independent studies were performed, one with 29 peritoneal dialysis patients and the other with 43 predialysis subjects. In both groups of patients, known oxidative stress markers, malonyldialdehyde (MDA) and carbonyl groups (CG) formation were measured. Additionally, in the predialysis group, glutathione in erythrocytes (GSH) was estimated. In peritoneal dialysis patients, the concentration of advanced glycation end products (AGEs) was found to be significantly increased and correlated with both markers of oxidative stress. In predialysis patients, the increment of newly described uremic toxin purine nucleotide end products (Me2PY and Me4PY) were found and significant correlation was observed between both compounds versus MDA (positive) and GSH (negative). This relationship was visible especially in patients with more advanced renal failure. CG concentration was within the normal values and did not show any correlation with estimated toxin concentrations. In summary, results of both studies suggest that the interrelationship between uremic toxicity and oxidative stress is an important component of uremic syndrome. Nevertheless, further complex studies are needed to elucidate closer pathogenic links.

Topics: Aged; Aldehydes; Biomarkers; Female; Glycation End Products, Advanced; Humans; Kidney Failure, Chronic; Male; Malondialdehyde; Middle Aged; Oxidative Stress; Peritoneal Dialysis; Purine Nucleotides; Uremia

Oxidative damage has been suggested to play a key role in accelerated atherosclerosis and to be involved in cardiovascular disease (CVD) of dialyzed patients who are at risk of increased oxidative stress. The purpose of the present study was to examine the relationship between the severity of CVD and some markers of oxidative stress and antioxidant activity in our hemodialyzed (HD) and peritoneal dialysis (PD) patients.. Plasma reactive oxygen metabolites, malondialdehyde and 4-hydroxynonenal (MDA-4HNE), thiols, alpha-tocopherol, and total antioxidant status (TAS) were measured in 55 HD and in 16 PD patients. CVD was considered as the result of variably combined cardiac, cerebral, and vascular pathologies which were scored and grouped in a single CVD index and analyzed with respect to the markers of the oxidative status. 16 normal subjects served as controls.. All patients showed evidence of increased oxidative stress which was more severe in HD than in PD patients and which was exacerbated by HD. When cardiac, cerebral, and vascular diseases were analyzed separately, plasma MDA-4HNE and TAS were significantly higher in more severely affected HD patients, but not in PD patients. In HD patients the CVD index was directly correlated with both MDA-4HNE and TAS (r = 0.42, p < 0.01; r = 0.39, p < 0.01) and inversely correlated with alpha-tocopherol (r = -0.32, p < 0.05). MDA-4HNE and TAS were directly correlated in HD patients and inversely correlated in control subjects.. Our data show that, in spite of increased antioxidant defense, there is a relationship between the degree of lipid peroxidation and the severity of CVD in HD patients. Moreover, these data underscore the utility of MDA-4HNE, alpha-tocopherol, and TAS in the evaluation of cardiovascular disease.

Topics: Aldehydes; Antioxidants; Cardiovascular Diseases; Female; Humans; Kidney Failure, Chronic; Lipid Peroxidation; Male; Malondialdehyde; Middle Aged; Oxidative Stress; Peritoneal Dialysis; Reactive Oxygen Species; Reference Values; Renal Dialysis; Vitamin E

Patients with end-stage renal failure undergoing haemodialysis (HD) are exposed to oxidative stress. Increased levels of malondialdehyde (MDA) were demonstrated in plasma of uraemic patients, indicating accelerated lipid peroxidation (LPO) as a consequence of multiple pathogenetic factors. The aim of our investigation was to examine the role of renal anaemia in oxidative stress in HD patients.. MDA and 4-hydroxynonenal (HNE) were measured in three groups of patients undergoing HD: group I comprised eight patients with a blood haemoglobin (Hb) < 10 g/dl (mean Hb = 8.1+/-1.3 g/dl), and group II were eight patients with a Hb > 10 g/dl (mean Hb=12.4+/-1.9g/dl); none of these 16 patients had been treated with human recombinant erythropoietin (rHuEpo). Group III comprised 27 patients with a mean Hb of 10.5+/-1.6 g/dl after long-term rHuEpo treatment.. Mean plasma concentrations of both MDA and HNE were significantly higher (P<0.0001) in all 43 HD patients than in 20 healthy controls (MDA 2.85+/-0.25 vs 0.37+/-0.03 microM, HNE 0.32+/-0.03 vs 0.10+/-0.01 microM). Comparing the three groups, it was shown that HD patients with a Hb <10 g/dl had significantly higher plasma levels of LPO products (MDA 3.81+/-0.86 microM, HNE 0.45+/-0.07 microM) than HD patients with a Hb >10g/dl (MDA 2.77+/-0.58 UM, HNE 0.25+/-0.05 microM), and than HD patients treated with rHuEpo (MDA 2.50+/-0.12 microM, HNE 0.29+/-0.03 microM). Furthermore, an inverse correlation between plasma concentration of LPO products and haemoglobin levels was seen (r=0.62, P<0.0001).. Radical generation in HD patients might be caused in part by renal anemia itself. Treatment with rHuEpo may decrease radical generation effectively in HD patients due to the increase in the number of red blood cells and blood haemoglobin concentration.

Topics: Adult; Aged; Aged, 80 and over; Aldehydes; Anemia; Erythrocyte Count; Erythropoietin; Female; Follow-Up Studies; Humans; Kidney Failure, Chronic; Lipid Peroxidation; Male; Malondialdehyde; Middle Aged; Oxidative Stress; Recombinant Proteins; Renal Dialysis; Retrospective Studies

Recombinant human erythropoetin beta; (rHuEPO) has not only an erythropoietic effect but also appears to affect production of cytokines and may improve nutritional status of dialysis patients. Darbepoetin alpha; is a new erythropoiesis-stimulating protein with a threefold longer serum half-life when compared with rHuEPO. The objective of this prospective study was to assess oxidative stress, inflammation, nutrition and hematological response in peritoneal dialysis (PD) patients who were switched from rHuEPO beta to darbepoetin alpha. 12 stable PD patients (6 M, 6 F; mean age 56.2 +/- 15.1 yr.) were evaluated during this study together with 22 healthy volunteers serving as a control group. All patients had been receiving erythropoetin beta subcutaneously once a week before they were reassigned to darbepoetin. The new drug was administered every other week for 6 months, in a dose equivalent to a weekly dose of previously taken rHuEPO. Hematology, iron status and biochemical profiles were evaluated monthly. Markers of oxidative stress: malondialdehyde/ 4-hydroxynoneal (MDA/4HNE), carbonyl groups (CG), oxyLDL and AGEs and markers of inflammation: CRP, TNF alpha, IL-6 were measured on rHuEPO beta before the switch to darbepoetin, and after 1st and 6th month of darbepoetin treatment. The assessment of nutritional status was determined by body mass index (BMI), serum albumin concentration and Subjective Global Assessment (SGA).. Mean levels of Hb and Hct were stable during 6 months of observation and not significantly different from the data observed for on rHuEPO. Nutritional status was good in 9 patients, 3 patients were malnourished at the beginning of this study as assessed by SGA and this status persisted to the end of observation. The levels of markers of oxidative stress and inflammation were statistically higher than in the control group (p < 0.05).. Darbepoetin alpha given subcutaneously once every 2 weeks is effective for the treatment of anemia in PD patients. Less frequent administration of darbepoetin has a biological response similar to weekly administration of rHuEPO.

Topics: Adult; Aldehydes; Anemia; Biomarkers; C-Reactive Protein; Darbepoetin alfa; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Follow-Up Studies; Hematinics; Humans; Inflammation; Injections, Subcutaneous; Kidney Failure, Chronic; Male; Malondialdehyde; Middle Aged; Nutritional Status; Oxidative Stress; Peritoneal Dialysis; Prospective Studies; Recombinant Proteins; Serum Albumin; Time Factors; Treatment Outcome

Patients with end-stage renal disease undergoing hemodialysis (HD) are exposed to oxidative stress. Increased levels of malondialdehyde (MDA) and 4-hydroxylnonenal (HNE) were found in plasma of uremic patients indicating accelerated lipid peroxidation (LPO) as a consequence of multiple pathogenetic factors. The catabolism and action of those products was already intensively studied. As highly reactive metabolites they are able to bind to proteins, nucleic acids, and other molecules. Doing so, they exert molecular signal effects in cells and are able to exacerbate tissue and organ damage, e.g. cardiotoxic effects. Since renal anemia was shown to promote oxidative stress as well, the aim of our investigation was to examine its role in HD patients. Therefore, two groups of HD patients were investigated (group I Hb < 10 g/dl, group II Hb > 10 g/dl) and serum concentrations of MDA, HNE, and of protein carbonyls, a marker for protein oxidation, were determined. All HD patients had significantly higher levels of the LPO products MDA and HNE compared with controls. However, group I patients showed higher MDA and HNE concentrations compared to group II patients. The same result could be seen for protein carbonyls. During HD concentration of both LPO products decreased. However, this was not the case for protein carbonyls. These results lead to the conclusion that optimized correction of the renal anemia may result in a significant reduction of oxidative stress and therefore in the reduction of organ tissue damage. In this way correction of renal anemia will reduce the cardiovascular risk and comorbidity of HD patients improving their prognosis.

Topics: Aldehydes; Anemia; Cardiovascular Diseases; Female; Humans; Kidney Failure, Chronic; Lipid Peroxidation; Male; Malondialdehyde; Middle Aged; Oxidation-Reduction; Oxidative Stress; Proteins; Renal Dialysis; Risk Factors

Homocysteine serum levels were measured in patients with end-stage renal disease in relation to severity of renal anemia and oxidative stress parameters such as 4-hydroxynonenal (HNE) and malondialdehyde (MDA). The predialytic homocysteine serum levels of the patients are five times as high as in healthy controls. It was found that homocysteine does not correlate to hemoglobin concentration and to oxidative stress, but rather to parameters of nutrition status such as albumine concentration and protein catabolic rate. The homocysteine accumulation represents a cardiovascular risk factor which is statistically independent of oxidative stress, but dependent on nutrition or energy status in patients with chronic renal failure.

Topics: Aldehydes; Anemia; Cardiovascular Diseases; Female; Hemoglobins; Homocysteine; Humans; Kidney Failure, Chronic; Male; Malondialdehyde; Middle Aged; Oxidative Stress; Renal Dialysis; Risk Factors

Lipid peroxidation (LPO) products formed after reaction of free radicals with membrane lipids are involved in the pathogenesis of cardiac diseases. Also in patients with end-stage renal disease (ESRD) LPO was shown to be accelerated and concentrations of non-enzymatic antioxidants were measured lower than in control subjects. However, up to now only limited knowledge about the role of antioxidant enzymes was available. Whether or not activity of those antioxidants might be induced due to oxidative stress in ESRD patients is not known. To answer the question the activity of 3 enzymatic antioxidants, superoxide dismutase (SOD), catalase (CAT), and glutathion peroxidase (GPx), was measured in red blood cells of the ESRD patients undergoing hemodialysis (2 groups: children and adults) and matching controls. LPO in these subjects was determined by measurement of the LPO product 4-hydroxynonenal (HNE) in blood plasma. Plasma HNE was significantly increased by factor 3 in both patient groups children and adults compared to the control groups. The activity of the enzymatic antioxidants was measured differently. While SOD was significantly lower in patients (children and adults) than in the matching controls this was not the case for catalase and GPx. While GPx activity in adult patients was comparable to that in the control groups (childrens and adults), the GPx in children with ESRD was almost twice as high than in the other groups. Since children were shown to have higher levels of glutathion, activated GPx might be a sign of adaptation of these children to the increased rate of oxidation.

Topics: Adaptation, Physiological; Adolescent; Adult; Aged; Aldehydes; Antioxidants; Catalase; Child; Erythrocytes; Female; Free Radical Scavengers; Glutathione Peroxidase; Humans; Kidney Failure, Chronic; Lipid Peroxidation; Male; Middle Aged; Oxidative Stress; Renal Dialysis; Superoxide Dismutase

Advanced glycation of proteins has been incriminated in the progressive alteration of the peritoneal membrane during chronic peritoneal dialysis (PD). Advanced glycation end products (AGEs) result from a modification of proteins by reactive carbonyl compounds (RCOs). RCOs resulting from glucose breakdown are present in commercial PD fluid. They also accumulate in uremic plasma. The present study was undertaken to evaluate the respective contribution of these two sources of RCOs in the genesis of peritoneal AGEs.. Three major RCOs formed during heat sterilization of PD fluid, that is, glyoxal, methylglyoxal, and 3-deoxyglucosone, and total RCOs were measured in commercial PD fluid and in PD effluent. The generation of pentosidine, used as a surrogate marker for AGEs, during one-week incubations of PD fluid and effluent samples fortified with bovine serum albumin (BSA) was measured by high-performance liquid chromatography. Peritoneal samples were stained with antibodies specific for two AGEs derived from carbohydrate-dependent RCOs, Nepsilon-(carboxymethyl)lysine (CML) and pentosidine, or for two advanced lipoxidation end products (ALEs) derived from lipid-dependent RCOs, malondialdehyde (MDA)-lysine and 4-hydroxynonenal (HNE)-protein adduct.. Glyoxal, methylglyoxal, and 3-deoxyglucosone were identified in commercial PD fluid. Their levels in PD effluents decreased with dwell time probably by diffusion into blood circulation. In contrast, the levels of total RCOs were initially low in commercial PD fluid, increased in PD effluent with dwell time probably by diffusion from circulation into the peritoneal cavity, and after 12 hours, reached values observed in uremic serum. The relevance of the rise in total RCOs for AGE formation is demonstrated by a parallel increase in the generation of pentosidine during incubations of PD effluents. In contrast with RCOs present in glucose-rich PD fluid, RCOs diffusing from uremic circulation originate from both carbohydrates and lipids. Their role in the modification of peritoneal proteins is demonstrated by the immunohistochemical study of peritoneal tissue. Two AGEs and two ALEs increase in parallel in the mesothelial layers and in vascular wall of small arteries in the peritoneum.. Protein modification of the peritoneum is determined not only by RCOs originating in PD fluid, but also by RCOs originating from the uremic circulation. The present data might be relevant to current attempts to improve PD fluid toxicity by lowering its glucose content.

Topics: Adult; Aged; Aldehydes; Arginine; Ascitic Fluid; Dialysis Solutions; Filtration; Glucose; Glycation End Products, Advanced; Hot Temperature; Humans; Kidney Failure, Chronic; Lipid Peroxidation; Lysine; Middle Aged; Peritoneal Dialysis; Peritoneum; Sterilization; Uremia

Free radical oxidation of human plasma low-density lipoprotein (LDL) produces 2-pentylpyrrole epitopes that are generated by reaction of 4-hydroxy-2-nonenal (HNE), a product of lipid oxidation, with protein lysyl residues. The HNE-derived 2-pentylpyrrole ("HNE-pyrrole") epitopes were detected with an enzyme-linked immunosorbent assay (ELISA) using antibodies (ON-KLH) raised against protein-bound 2-pentylpyrrole obtained by the reaction of 2-oxononanal (ON) with keyhole limpet hemocyanin (KLH). HNE-pyrrole epitopes in human plasma are not associated primarily with LDL protein, apolipoprotein (apo) B, since only 15% of the total HNE-pyrrole immunoreactivity is removed by immunoprecipitation of apo B. The levels of ON-KLH immunoreactivity detected in human plasma were found to be significantly elevated in renal failure and atherosclerosis patients when compared to those in healthy volunteers. HNE-pyrrole immunoreactivity was also detected in atherosclerotic plaques. The highest levels were associated with extracellular connective tissue. Levels of ON-KLH immunoreactivity in human plasma far exceed levels of free HNE, presumably because of the rapid clearance of free relative to protein-bound HNE. Therefore, HNE-pyrrole epitopes provide a more indelible marker of oxidative injury than levels of free HNE.

Topics: Aldehydes; Arteriosclerosis; Carotid Arteries; Humans; Immunohistochemistry; Kidney Failure, Chronic; Lipoproteins, LDL; Oxidation-Reduction; Pyrroles

Nephron loss leads to increased production of reactive oxygen intermediates. We measured the effect of carvedilol, a beta-blocking drug with radical scavenging properties, on renal function, glomerulosclerosis, antioxidant enzyme status and in vivo hydrogen peroxide (H2O2) production in rats with chronic renal failure caused by 5/6 nephrectomy (remnant kidney) and compared results to data obtained with propranolol, a beta-blocking drug without scavenging characteristics. Carvedilol and propranolol were administered during 11 weeks following reduction of nephron number. Kidneys were examined using enzymatic and histological techniques. Both carvedilol and propranolol decreased systolic blood pressure. Compared to propranolol, carvedilol offered some additional beneficial effects on renal function, particularly with regard to glomerulosclerosis. Lipid peroxidation, evaluated by malonaldehyde and 4-hydroxynonenal concentration in cortex homogenates, was decreased in carvedilol-treated rats only. Superior beneficial effect of carvedilol treatment is not linked to a significant up-regulation of the activities of the remnant kidney antioxidant enzymes (catalase, glutathione peroxidase and superoxide dismutase) or to a decreased in vivo H2O2 production.

Topics: Adrenergic beta-Antagonists; Aldehydes; Animals; Antioxidants; Blood Pressure; Carbazoles; Carvedilol; Free Radical Scavengers; Glomerulosclerosis, Focal Segmental; Hydrogen Peroxide; Kidney Cortex; Kidney Failure, Chronic; Lipid Peroxidation; Male; Malondialdehyde; Nephrectomy; Propanolamines; Propranolol; Rats; Rats, Wistar