Effects of vitamin E-coated membrane dialyser on markers of oxidative stress and inflammation in patients on chronic haemodialysis

Profiling oxidative stress markers and cardiovascular complications in chronic kidney disease patients supplemented with vitamin E

Introduction

Cardiovascular diseases are common complications in chronic kidney disease (CKD). Oxidative stress associated with renal and metabolic dysfunctions is one of the cardiovascular complications (CVC) in haemodialysis patients. The aim of the present study is to analyse the oxidative stress markers in CDK patients supplemented with antioxidants and vitamin E, with monitoring of CVC.

Material and methods

This was a cross-sectional study conducted on 99 subjects. CKD patients received oral supplementation of vitamin E (300 mg/day) for 2 years. Oxidative stress markers, nitric oxide (NO); myeloperoxidase (MPO); oxidized low-density lipoprotein (LDLox); malondialdehyde (MDA) and glutathione were measured before and after the vitamin treatment.

Results

NO (62.62 ±2.80 μmol/l), LDLox (10.55 ±4.62 μmol/l), MDA (6.11 ±2.83 μmol/l) and MPO (53.35 ±3.82 UI/ml) were overconcentrated, while glutathione (62.09 ±4.15 UI/ml) was less concentrated in CKD patients with cardiovascular complications, compared to those without cardiovascular complications (67.08 ±1.90 μmol/l, 31.18 ±5.25 μmol/l, 16 ±6.47 μmol/l, 57.00 ±7.24 UI/ml, 43.09 ±3.33 UI/ml, respectively). After 2 years of vitamin E treatment, the overall cardiovascular complications were not significantly decreased.

Conclusions

These results showed that oral complementation with vitamin E did not affect the occurrence of cardiovascular complications associated with CKD. These findings may pave the way for future innovative strategies for antioxidant supplementation in CKD patients.

Association between dietary vitamin E intake and chronic kidney disease events in US adults: a cross-sectional study from NHANES 2009-2016

Background

The relationship between vitamin E supplementation and the prevalence of chronic kidney disease (CKD) is unclear. We discussed the relationship between vitamin E intake and CKD prevalence and further investigated the effect on different CKD risk strata.

Methods

We ultimately included 20 295 participants from the National Health and Nutrition Examination Survey (NHANES) database from 2009 to 2016. Multiple logistic regression and restricted cubic splines (RCS) were applied to explore the relationship between vitamin E intake and CKD prevalence and risk stratification. Subgroup analysis was applied to assess the stability of the association between vitamin E intake and CKD.

Results

In the CKD prevalence study, we found a negative association between high vitamin E intake and CKD prevalence through an adjusted multiple logistic regression model, the odds ratio (OR) was 0.86 [95% confidence interval (CI) 0.74-1.00; P for trend = .041] and RCS showed a nonlinear negative correlation (P-nonlinear = .0002, <.05). In the CKD risk stratification study, we found that in very high-risk patients, the OR was 0.51 (95% CI 0.32-0.84; P for trend = .006) and the RCS also showed a nonlinear negative correlation (P-nonlinear <.0001, <.05). Subgroup analysis demonstrated that the correlations were stable across populations (P-values >.01 for all interactions).

Conclusion

Dietary vitamin E intake was negatively associated with the prevalence of CKD in US adults. Increased vitamin E intake was a protective factor across CKD risk strata, and as vitamin E intake increased, there was a non-linear downward trend in the proportion progressing to very high-risk CKD.

Vitamin E Treatment Improves the Antioxidant Capacity of Patients Receiving Dialysis: A Systematic Review and Meta-Analysis

SCOPE

To summarize the effect of vitamin E-coated dialyzer membranes (VEMs) treatment or oral vitamin E intake on antioxidant molecules, such as superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), and total antioxidant level in patients receiving dialysis.

METHODS AND RESULTS

A literature search of PubMed, Embase, CNKI, and the Cochrane Library databases is performed from inception to July 1, 2023, with no language nor country restrictions. Twenty-four experimental studies involving 512 patients undergoing dialysis are selected for meta-analysis. The levels of antioxidant markers in the blood of patients receiving hemodialysis (HD) improve with long-term VEMs treatment (p = 0.016). According to the findings of each antioxidant index, there is a significant increase in the levels of erythrocyte-derived SOD (p = 0.047), CAT (p = 0.029), and plasma-derived total antioxidant level (p < 0.001). The antioxidant marker levels in patients receiving HD are significantly increased by oral vitamin E intake (p < 0.001). Erythrocyte-derived SOD (p = 0.003), GPX (p < 0.001), and CAT (p = 0.001) substantially improves after 2-6 months of intervention with oral vitamin E preparation. The antioxidant index of patients receiving peritoneal dialysis (PD) is unaffected by oral vitamin E treatment (p = 0.945).

CONCLUSION

Vitamin E therapy has a favorable effect on the retention of antioxidant compounds in patients undergoing dialysis.

Alleviation of Oxidative Stress during Hemodialysis Sessions by Hemodialysis Membrane Innovation: A Multidisciplinary Perspective

Oxidative stress is prevalent in end-stage kidney disease patients receiving chronic hemodialysis and is associated with heavy cardiovascular disease burdens and increased mortality risks. Hemoincompatible hemodialysis membranes per se contribute to the activation of oxidative reactions and the generation of oxygen free radicals. Since the early 1990s, vitamin E-coated membranes have been extensively used in hemodialysis patients to reduce oxidative stress during hemodialysis sessions. However, the beneficial effects of vitamin E-coated membranes versus unmodified synthetic membranes on long-term patient-centered outcomes, such as survival, quality of life, and prevalence of cardiovascular diseases, remain controversial. Accordingly, novel antioxidant hemodialysis membranes were prepared to replace the use of vitamin E-coated membranes despite the translational research on these membranes unfortunately coming to a standstill. In this review, we first summarize the state-of-the-art on the use of vitamin E-coated membranes in hemodialysis patients to highlight their strengths and limitations. Then, we discuss the latest advances in fabricating antioxidant hemodialysis membranes and provide perspectives to bridge knowledge gaps between laboratorial investigations and clinical practice in fabricating antioxidant hemodialysis membranes.

Advances in Enhancing Hemocompatibility of Hemodialysis Hollow-Fiber Membranes

Hemodialysis, the most common modality of renal replacement therapy, is critically required to remove uremic toxins from the blood of patients with end-stage kidney disease. However, the chronic inflammation, oxidative stress as well as thrombosis induced by the long-term contact of hemoincompatible hollow-fiber membranes (HFMs) contribute to the increase in cardiovascular diseases and mortality in this patient population. This review first retrospectively analyzes the current clinical and laboratory research progress in improving the hemocompatibility of HFMs. Details on different HFMs currently in clinical use and their design are described. Subsequently, we elaborate on the adverse interactions between blood and HFMs, involving protein adsorption, platelet adhesion and activation, and the activation of immune and coagulation systems, and the focus is on how to improve the hemocompatibility of HFMs in these aspects. Finally, challenges and future perspectives for improving the hemocompatibility of HFMs are also discussed to promote the development and clinical application of new hemocompatible HFMs.

Graphical Abstract

Erythropoietin Resistance Development in Hemodialysis Patients: The Role of Oxidative Stress

Oxidative stress (OS) is considered a significant risk factor for the development of anemia in patients treated by regular hemodialysis (HD). Moreover, OS represents a risk factor for the development of erythropoietin (EPO) resistance in these patients. The aim of this study was to examine the role of OS regarding EPO resistance development in patients treated by regular HD. 96 patients treated with standard HD and on-line hemodiafiltration were included in this study. The patients were treated with short-acting and long-acting EPOs for anemia. The concentration of superoxide anion radical, hydrogen peroxide, thiobarbituric acid reactive substances, and nitric oxide in the form of nitrites and the activity of catalase, superoxide dismutase and reduced glutathione were measured in patients' blood spectrophotometrically. Standard biochemical analysis, inflammatory markers, nutritional status, HD parameters, and erythropoietin resistance index were also determined. Patients with resistance to short-acting EPO had significantly lower concentration of hemoglobin in the blood and hematocrit value, a significantly higher serum ferritin concentration, and significantly lower catalase activity in erythrocytes than patients without EPO resistance. Patients with resistance to long-acting EPO have a significantly lower hemoglobin concentration in the blood, hematocrit values, and serum concentration of prealbumin and vitamin D, as well as significantly higher concentration of C-reactive protein, superoxide anion, and hydrogen peroxide concentration than those without resistance. OS significantly contributes to EPO resistance development. OS, higher ferritin and CRP levels, lower hemoglobin, hematocrit and prealbumin levels, and vitamin D deficiency represent significant risk factors for EPO resistance development in HD patients.

Beneficial Effects of Vitamin E Supplementation on Endothelial Dysfunction, Inflammation, and Oxidative Stress Biomarkers in Patients Receiving Hemodialysis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Inflammation and oxidative stress are closely related to cardiovascular complications and atherosclerosis, and have the potential to lead to an increase in death in patients receiving hemodialysis. Vitamin E has antioxidant and anti-inflammatory properties. We conducted a systematic review and meta-analysis to assess the effects of vitamin E supplementation on endothelial dysfunction, inflammation, and oxidative stress biomarkers in adult patients receiving hemodialysis. We searched the MEDLINE, EMBASE, Web of Science, and Cochrane Library databases and identified randomized controlled trials of adult patients receiving hemodialysis until 30 August 2021. A total of 11 trials with 491 randomized patients were included. The pooled data indicated that vitamin E supplementation significantly decreased intercellular adhesion molecule-1 [standardized mean difference (SMD): -1.35; 95% confidence interval (CI): -2.57, -0.13; p = 0.03, I2 = 89%], vascular cell adhesion molecule-1 (SMD: -1.08; 95% CI: -2.05, -0.11; p = 0.03, I2 = 81%), C-reactive protein (SMD: -0.41; 95% CI: -0.75, -0.07; p = 0.02, I2 = 64%), and malondialdehyde (SMD: -0.76; 95% CI: -1.26, -0.25; p = 0.003, I2 = 77%) levels, but not interleukin-6 levels compared to those in the control group. Our results suggest that vitamin E supplementation may help alleviate oxidative stress and both vascular and systemic inflammation in patients receiving hemodialysis.

Polyvinylpyrrolidone in hemodialysis membranes: Impact on platelet loss during hemodialysis

INTRODUCTION

Hydrophilic modification with polyvinylpyrrolidone (PVP) increases the biocompatibility profile of synthetic dialysis membranes. However, PVP may be eluted into the patient's blood, which has been discussed as a possible cause for adverse reactions rarely occurring with synthetic membranes. We investigated the content of PVP and its elution from the blood-side surface from commercially available dialyzers, including the novel FX CorAL, with PVP-enriched and α-tocopherol-stabilized membrane, and link the results to the level of platelet loss during dialysis as a maker of biocompatibility.

METHODS

Six synthetic, PVP containing, dialyzers (FX CorAL, FX CorDiax [Fresenius Medical Care]; Polyflux, THERANOVA [Baxter]; ELISIO [Nipro]; xevonta [B. Braun]) were investigated in the present study. The content of PVP on blood-side surface was determined with X-ray photoelectron spectroscopy (XPS). The amount of elutable PVP was measured photometrically after 5 h recirculation. The level of platelet loss was evaluated in an ex vivo recirculation model with human blood.

FINDINGS

Highest PVP content on the blood-side surface was found for the polysulfone-based FX CorAL (26.3%), while the polyethersulfone-based THERANOVA (15.6%) had the lowest PVP content. Elution of PVP was highest for the autoclave steam-sterilized THERANOVA (9.1 mg/1.6 m² dialyzer) and Polyflux (9.0 mg/1.6 m² dialyzer), while the lowest PVP elution was found for the INLINE steam sterilized FX CorAL and FX CorDiax (<0.5 mg/1.6 m² dialyzer, for both). Highest platelet loss was found for xevonta (+164.4% compared to the reference) and the lowest for the FX CorAL (-225.2%) among the polysulfone-based dialyzers; among the polyethersulfone-based dialyzers, THERANOVA (+95.5%) had the highest and ELISIO (-52.1%) the lowest platelet loss.

DISCUSSION

Polyvinylpyrrolidone content and elution differ between commercially available dialyzers and were found to be linked to the membrane material and sterilization method. The amount of non-eluted PVP on the blood-side surface may be an important determinant for the biocompatibility of dialyzers.

Application and Efficacy of Vitamin E-Bonded Polysulfone Membrane in Acute Blood Purification Therapy

INTRODUCTION

Acute blood purification therapy (BPT) has been evaluated in the context of intensive care for serious conditions related to systemic inflammation, but its mechanism and efficacy are not fully understood.

OBJECTIVE

This study examined the feasibility of using vitamin E-bonded polysulfone membranes (VEPS) for BPT in a LPS-induced rat model of systemic inflammation.

METHODS

To evaluate the efficacy of BPT with a VEPS membrane, polysulfone (PS) membranes conventionally used in intensive care were bonded with the antioxidant vitamin E and used in a rat model of lipopolysaccharide (LPS)-induced systemic inflammation. BPT using a PS membrane (PS group) or a VEPS membrane (VEPS group) was performed 6 h after administration of LPS. Extracorporeal circulation was established in normal rats as a control (sham group). Survival rates, histology of lung specimens, and levels of myeloperoxidase (MPO) and high mobility group box-1 (HMGB-1) were examined in each group.

RESULTS

Survival rates at 24 h after LPS administration were 100% in the VEPS group and 50% in the PS group. Pulmonary architecture was largely maintained and the level of infiltration of inflammatory cells remained moderate in the VEPS group. Levels of active MPO before and after BPT were significantly higher in the PS and VEPS groups than in the sham group, with no significant differences between the PS and VEPS groups. HMGB-1 levels were significantly elevated after BPT in the PS group.

CONCLUSIONS

This study demonstrated that use of the VEPS membrane for BPT increased survival rate and reduced lung injury in a rat model of systemic inflammatory response syndrome (SIRS), suggesting the possible use of VEPS membranes in the treatment of serious conditions related to systemic inflammation.

Doping Polysulfone Membrane with Alpha-Tocopherol and Alpha-Lipoic Acid for Suppressing Oxidative Stress Induced by Hemodialysis Treatment

The reduction of free radicals by bioactive membranes used for hemodialysis treatment is an important topic due to the constant rise of oxidative stress-associated cardiovascular mortality by hemodialysis patients. Therefore, it is urgent to find an effective solution that helps to solve this problem. Polysulfone membranes enriched with α-lipoic acid, α-tocopherol, and with both components are fabricated by spin coating. The antioxidant properties of these membranes are evaluated in vitro by determining the lipid-peroxidation level and the total antioxidant status of the blood plasma. The biocompatibility is assessed by quantifying the protein adsorption, platelet adhesion, complement activation, and hemolytic effect. All types of membranes show in vitro antioxidant activity and a trend to reduce oxidative stress in vivo; the best results show membranes prepared with a combination of both compounds and prove to be nonhemolytic and hemocompatible. Moreover, the membrane specific separation ability for the main waste products is not affected by antioxidants incorporation.

Relation Between Oxidative Stress and Carotid Artery Atherosclerosis in Hemodyalisis Patients

INTRODUCTION Oxidative stress represents a significant risk factor for the accelerated development of atherosclerosis in a population of patients on regular hemodialysis. Oxidative stress induced by hemodialysis can be triggered with both the bioincompatibility of dialysis membrane and increased endotoxin concentration in a hemodialysis solution.

AIM The aim of this study was to investigate the correlation between the parameters of oxidative stress, microinflammation, nutrition, secondary hyperparathyroidism and carotid artery intima-media thickness in patients on regular hemodialysis.

METHODS One hundred and twenty five patients treated with standard hemodialysis and on-line hemodiafiltration with “high-flux” polysulfone dialysis membrane were examined. The following parameters of oxidative stress were measured : index of lipid peroxidation - measured as TBARS, nitric oxide in the form of nitrite - NO2-, super oxide anion radical - O2- and hydrogen peroxide - H2O2, catalase, superoxide dismutase (SOD) and reduced glutathione activity. For statistical analysis of results, the following tests were used: the Kolmogorov-Smirnov test, the Spirman test and the Pearson correlation test.

RESULTS Oxidative stress affects atherosclerosis of the carotid arteries in patients treated with regular hemodialysis and online hemodiafiltration. There is a statistically significant positive correlation between H2O2 concentration and the thickness of the carotid arteries` intima-media. High statistically significant positive correlation was found between TBARS concentration and carotid arteries intima-media thickness, while a high statistically significant negative correlation was found between SOD activity and a carotid artery intima-media thickness. There is a statistically significant negative correlation between the serum albumin and prealbumin concentration and a carotid artery intima-media thickness.

CONCLUSION Oxidative stress may be a significant risk factor for the carotid artery atherosclerosis development in patients treated with regular hemodialysis.

Vitamin E-Coated Polysulfone Membrane-Based Hemodiafiltration Attenuates Inflammation in a Rat Model of Lipopolysaccharide-Induced Systemic Inflammation

BACKGROUND

Acute blood purification (ABP) therapy is used regularly in the clinical setting and reportedly alleviates organ failure associated with severe systemic inflammatory responses, leading to reduced mortality. The present study aimed to determine whether there is a difference in efficacy between polysulfone (PS) membranes, which are currently used regularly in the clinical setting, and vitamin E-coated polysulfone (VEPS) membranes, which are anticipated to exhibit the antioxidant and anti-inflammatory properties of vitamin E.

METHODS

Male Wistar rats (n=15/group) were intravenously administered 10 mg/kg of lipopolysaccharide (LPS) to establish a systemic inflammatory response model. Six hours after LPS administration, hemodiafiltration (HDF) was performed for 30 minutes using a PS or VEPS membrane under general anesthesia. Blood was collected at various time points, lung tissue was evaluated histologically, and 24-hour survival was assessed.

RESULTS

The rats in the VEPS group tended to have a higher survival rate than those in the PS group when undergoing HDF, although the difference was not significant. With respect to lung tissue, the inflammatory response was suppressed to a greater extent in the VEPS group than the PS group. Serum interleukin (IL)-6 levels were reduced at an early stage, plasma antioxidant activity was increased, and oxidative stress was reduced in the VEPS group compared to the PS group.

CONCLUSION

Relative to PS membrane-based HDF, the survival rate tended to improve and inflammation was subdued earlier due to the antioxidant activity and early attenuation of inflammation associated with VEPS membrane-based HDF.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

Mitochondria: a new therapeutic target in chronic kidney disease

Cellular metabolic changes during chronic kidney disease (CKD) may induce higher production of oxygen radicals that play a significant role in the progression of renal damage and in the onset of important comorbidities. This condition seems to be in part related to dysfunctional mitochondria that cause an increased electron "leakage" from the respiratory chain during oxidative phosphorylation with a consequent generation of reactive oxygen species (ROS). ROS are highly active molecules that may oxidize proteins, lipids and nucleic acids with a consequent damage of cells and tissues. To mitigate this mitochondria-related functional impairment, a variety of agents (including endogenous and food derived antioxidants, natural plants extracts, mitochondria-targeted molecules) combined with conventional therapies could be employed. However, although the anti-oxidant properties of these substances are well known, their use in clinical practice has been only partially investigated. Additionally, for their correct utilization is extremely important to understand their effects, to identify the correct target of intervention and to minimize adverse effects. Therefore, in this manuscript, we reviewed the characteristics of the available mitochondria-targeted anti-oxidant compounds that could be employed routinely in our nephrology, internal medicine and renal transplant centers. Nevertheless, large clinical trials are needed to provide more definitive information about their use and to assess their overall efficacy or toxicity.

C-reactive Protein: Repeated Measurements will Improve Dialysis Patient Care

Systemic inflammation is a common feature in the uremic phenotype and associates with poor outcomes. The awareness regarding the importance of inflammation assessment in chronic kidney disease (CKD) patients has risen in recent years, and despite the development of novel biomarkers, C-reactive protein (CRP) is still the most measured inflammatory parameter. Notwithstanding, the possible weak points of CRP determination, this biomarker has demonstrated being useful both for guidance in clinical practice and for risk estimation. In addition, regular determination of CRP among dialysis patients has been associated with better outcomes in different dialysis facilities. Because persistent inflammation may be a silent reflection of various pathophysiologic alterations in CKD, it is crucial that inflammatory markers are regularly monitored and therapeutic attempts be made to target this inflammation.

Glycemic load is associated with oxidative stress among prevalent maintenance hemodialysis patients

BACKGROUND

High glycemic index (GI) and glycemic load (GL) are associated with increased levels of oxidative stress and systemic inflammation in the general population. Maintenance hemodialysis (MHD) patients are known to have excessive oxidative stress burden and inflammation. In this study, we examined the relationship between dietary GI or GL and markers of oxidative stress or inflammation among prevalent MHD patients.

METHODS

A registered dietitian obtained GI, GL and other dietary data from 58 MHD patients. Two separate 24-h diet recalls (a hemodialysis day and a non-hemodialysis day) were analyzed using the Nutrition Data System for Research (NDS-R) software. Plasma or serum concentrations of F2-isoprostanes, high sensitivity C-reactive protein (hsCRP), leptin and adiponectin (ADPN) were measured in fasting state. Fat mass was measured by dual-energy X-ray absorptiometry (DEXA). Cross-sectional associations between GI, GL and markers of interest were examined by multiple regression analysis with adjustment for potential covariates.

RESULTS

Mean (±SD) age, body mass index (BMI) and total trunk fat were 47 ± 12 years, 29.5 ± 6.8 kg/m(2) and 16.4 ± 8.8 kg, respectively. Dietary GI was associated with trunk fat (r = -0.182, P = 0.05) but not with F2-isoprostanes and hsCRP. In contrast, GL was significantly associated with F2-isoprostanes (P = 0.002), in unadjusted analysis, which remained in adjusted analyses, adjusting for age and sex (P = 0.005), and after adjusting for BMI, trunk fat and waist/hip ratio (P = 0.004). Addition of leptin or ADPN did not alter the significance of the association. GL also correlated with hsCRP (P = 0.03), but this association was modified by BMI and trunk fat.

CONCLUSIONS

Dietary GL is significantly associated with markers of oxidative stress and inflammation among prevalent MHD patients, independent of the body composition and adipocytokines. These data indicate the importance of the contents of dietary nutrient intake composition and its potential role in determining the metabolic disturbances in MHD patients.

Impact of inflammation on anti-oxidative effects of vitamin E-coated membrane dialyzer in patients on chronic hemodialysis

Hemodialysis (HD) with the use of vitamin E-coated membrane (VEM) dialyzers is shown to exert anti-inflammatory and antioxidative effects in patients with end-stage renal disease on HD. However, the association of baseline inflammatory status with the antioxidative effects of VEM has not been investigated thus far. Thirty-five stable end-stage renal disease patients treated with VEM for 6 months were enrolled in the present prospective, observational cohort study. For the previous 3 months minimum, 17 (48%) patients were dialyzed with a cellulose, eight (23%) patients with a hemophane, and 10 (29%) patients with a polysulfone 1.2 to 1.5 m(2) hollow fiber dialyzer. The effects of treatment on oxidized low-density lipoprotein (oxLDL) were stratified according to half percentiles of baseline serum logC-reactive protein and interleukin-6, and the association between treatment goal, arbitrarily defined as a minimum 30% decrease in baseline oxLDL, was assessed with the use of logistic regression analysis. The higher C-reactive protein and interleukin-6 half percentiles were independently and additively associated with a higher odds ratio for achieving treatment goal. Adjustment for baseline oxLDL, age, sex, HD duration, smoking, and body mass index did not attenuate the odds ratios, whereas the history of diabetes, as primary renal disease, significantly decreased the odds ratio for achieving treatment goal. Increased baseline C-reactive protein and interleukin-6 are independent, additive factors associated with the effect of VEM on oxLDL in HD patients.

A randomized controlled trial evaluating the erythropoiesis stimulating agent sparing potential of a vitamin E-bonded polysulfone dialysis membrane

Background

Vitamin E (VE) bonded polysulfone dialysis membranes have putative erythropoiesis stimulating agent (ESA)-sparing and anti-inflammatory properties based on data from a small number of studies. We sought to investigate this in a large, prospective 12-month randomized controlled trial.

Methods

Two-hundred and sixty prevalent haemodialysis (HD) patients were randomized to dialysis with VE-bonded polysulfone membranes or non-VE-bonded equivalents. All ESA-dosing was performed by means of a computer-based anaemia management decision support system. Monthly data were used to calculate the ESA resistance index (ERI) and blood tests were performed at baseline, 6 and 12 months for measurement of C-reactive protein (CRP) levels.

Results

Of the 260 patients, 123 were randomized to dialysis with the VE-membrane and 12-month data was available for 220 patients. At the study population level, no beneficial effect of the VE membranes on the ERI or CRP levels was observed. Post hoc analyses indicated that there was a significant fall in ERI for patients with the highest baseline ESA resistance dialysed with the VE (9.28 [7.70–12.5] versus 7.70 [5.34–12.7] IU/week/kg/g/dL Hb, P = 0.01) but not the control membranes (9.45 [7.62–12.3] versus 8.14 [4.44–15.6] IU/week/kg/g/dL Hb, P = 0.41); this was not attributable to changes in CRP levels.

Conclusions

Wholesale switching of all chronic HD patients to dialysis with VE-bonded polysulfone membranes appears not to be associated with improvements in ESA-responsiveness or CRP. These membranes may have utility in patients with heightened ESA resistance.

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.

The effects of vitamin E-coated membrane dialyzer compared to simvastatin in patients on chronic hemodialysis

BACKGROUND

We investigated the effects of the use of vitamin E-coated membrane (VEM) dialyzer in comparison to simvastatin on markers of chronic inflammation, oxidative stress, and endothelial cell apoptosis in ten patients on chronic hemodialysis (HD), aiming at distinguishing the different treatment effects and their time sequence on these pathogenetic routes.

METHODS

Ten HD patients were sequentially submitted to a 6-month treatment with the use of VEM and 10 mg of simvastatin daily, interrupted by a 3-month washout period. At baseline, at 3, and 6 months of each trial, serum C-reactive protein (CRP), apolipoprotein (Apo) A1 and B, lipoprotein-a [Lp(a)], high-sensitivity interleukin-6 (hsIL-6), monocyte chemoattractant protein-1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), soluble Fas (sFas), soluble Fas ligand (sFasL), and plasma oxidized low-density lipoproteins (oxLDL) levels were determined.

RESULTS

VEM treatment resulted in a significant decrease in CRP, IL-6, sICAM-1 at 3 months, and oxLDL at 6 months, compared to baseline. Simvastatin resulted in a significant decrease in CRP, which correlated with decreases in both total (r = 0.87, p < 0.05) and low-density lipoprotein cholesterol, IL-6, sICAM-1, sVCAM-1, oxLDL, and sFas at 6 months, compared to baseline. Simvastatin effects on sVCAM-1 (mean difference = 652 ng/mL; 95% CI = 294 to 2686; p < 0.05) and sFas (mean difference = 1284 pg/mL; 95% CI = 510 to 1910; p < 0.05) differed significantly from the corresponding VEM effects.

CONCLUSIONS

The 6-month use of VEM resulted in more direct and immediate anti-inflammatory effects compared with those caused by the 6-month treatment with simvastatin. Simvastatin caused a more intense decrease in the markers of inflammation, which was in part correlated with its lipid-lowering effects.

Matrix metalloproteinases and soluble Fas/FasL system as novel regulators of apoptosis in children and young adults on chronic dialysis

The system of membrane receptor Fas and its ligand FasL compose one of the main pathways triggering apoptosis. However, the role of their soluble forms has not been clarified yet. Although sFasL can be converted from the membrane-bound form by matrix metalloproteinases (MMPs), there are no data on relations between sFas/sFasL, MMPs and their tissue inhibitors (TIMPs) in patients on chronic dialysis—neither children nor adults. The aim of our study was to evaluate serum concentrations of sFas, sFasL, and their potential regulators (MMP-2, MMP-7, MMP-9, TIMP-1, TIMP-2), in children and young adults chronically dialyzed. Twenty-two children on automated peritoneal dialysis (APD), 19 patients on hemodialysis (HD) and 30 controls were examined. Serum concentrations of sFas, sFasL, MMPs and TIMPs were assessed by ELISA. Median values of sFas, sFasL, sFas/sFasL ratio, MMP-2, MMP-7, MMP-9, TIMP-1 and TIMP-2 were significantly elevated in all dialyzed patients vs. controls, the highest values being observed in subjects on HD. A single HD session caused the decrease in values of all parameters to the levels below those seen in children on APD. Regression analysis revealed that MMP-7 and TIMP-1 were the best predictors of sFas and sFasL concentrations. Children and young adults on chronic dialysis are prone to sFas/sFasL system dysfunction, more pronounced in patients on hemodialysis. The correlations between sFas/sFasL and examined enzymes suggest that MMPs and TIMPs take part in the regulation of cell death in the pediatric population on chronic dialysis, triggering both anti- (sFas) and pro-apoptotic (sFasL) mechanisms.