Increased Red Blood Cell Survival Reduces the Need of Erythropoietin in Hemodialyzed Patients Treated with Exogenous Glutathione and Vitamin E-Modified Membrane

Effect of Vitamin E-Coated Dialysis Membranes on Anemia in Patients with Chronic Kidney Disease: An Italian Multicenter Study

Background

Increased oxidant stress is increasingly recognized as a crucial factor in anemia in patients with chronic kidney disease. Vitamin E-coated membranes (VECMs) consist of a multilayer membrane with liposoluble vitamin E on the blood surface allowing direct free radical scavenging at the membrane site, which is of potential clinical benefit. Our objective was to examine the effect of VECMs on anemia in chronic hemodialysis (HD).

Methods

We enrolled 172 stable chronic HD patients (94 men, 78 women, age 65.4 ± 13.4 years) in an open-label multicenter study. They were shifted from their previous dialyzer to VECM for 1 year. Hemoglobin (Hb) levels and recombinant human erythropoietin (rHuEpo) dosage were analyzed after 4, 8, and 12 months on the VECM and compared with baseline values using paired tests.

Results

Hb significantly increased from 10.9 ± 1.2 g/dL at baseline to 11.7 ± 1.2 g/dL after 12 months (p<0.001) on VECMs. Conversely, the rHuEpo dosage decreased from 7,762 ± 5,865 IU/week at baseline to 6,390 ± 5,679 IU/week after 12 months (p<0.001). The proportion of patients who were at target Hb levels (European Best Practice Guidelines) increased from 49.4% at baseline to 80% after 12 months (p<0.001).

Conclusions

Dialysis with VECM in stable chronic HD patients was associated with significantly improved Hb levels and lower rHuEpo requirements. These results suggest that the antioxidant properties of VECMs may impact favorably on anemia management in chronic HD patients. Possible mechanisms include enhanced membrane biocompatibility, reduced oxidative stress and inflammation with VECMs, resulting in improved red blood cell survival and/or rHuEpo responsiveness. This therapy may potentially contribute to more effective anemia management in hemodialysis patients, and merits further rigorous study.

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.

Development of vitamin E-modified polysulfone membrane dialyzers

Oxygen radicals have recently been attracting close attention because of their involvement in tissue damage and their close relationship to various clinical conditions. It has been suggested that hemodialysis increases oxidative stress, triggering the development of complications such as atherosclerosis and dialysis-related amyloidosis. We recently developed a dialyzer containing a highly functional polysulfone membrane on which vitamin E had been bonded (PS-ViE). The present study was undertaken to evaluate the biocompatibility of this membrane and to conduct other experiments on the membrane in vitro. Human blood was dialyzed with minidialyzers (300-600 cm(2) membrane area) made of PS-ViE, cellulose, or untreated polusulfone (PS), and the effects of the dialyzers on complements (C3a, C4a, and C5a), cytokines (IL-1beta and IL-8), and granulocyte elastase as well as their anti-oxidative activity were investigated (n = 6). The effect of PS-ViE on complement activation and its effects on cytokines were comparable to those of PS membrane, whereas granulocyte elastase following dialysis with the PS-ViE membrane tended to be lower than that seen with PS membrane. The effects of PS-ViE-induced methemoglobin, lipid peroxide, and oxygen radicals were significantly less than those of PS membrane, indicating the antioxidative activity of PS-ViE. Vitamin E-modified polysulfone membrane dialyzers were found to have favorable effects on the immune system and to express antithrombotic and antioxidative effects.

Effect of vitamin E-bonded dialyzer on eosinophilia in haemodialysis patients

BACKGROUND

Eosinophilia in haemodialysis patients probably results from allergy to haemodialysis-related materials, including dialyzer membranes. We examined the effects of vitamin E-bonded dialyzers on eosinophil counts in haemodialysis patients.

METHODS

We enrolled seven patients who were on regular haemodialysis and had sustained eosinophilia. White blood cell, eosinophil, CD4- and CD8-positive lymphocyte counts, and serum interleukin-5 (IL-5) and IgE levels were determined before, 2 and 4 weeks after switching to vitamin E-bonded dialyzers.

RESULTS

Eosinophil and CD4-positive lymphocyte counts and serum IL-5 were significantly (P = 0.003, 0.003 and 0.031, respectively) decreased after switching to vitamin E-bonded dialyzers. CD8-positive lymphocyte counts and serum IgE levels were unaltered. Crossover tests in two cases reproduced the higher eosinophilia within 4 weeks after returning to the original non-vitamin E-bonded dialyzer.

CONCLUSION

Vitamin E-bonded dialyzers may ameliorate eosinophilia through a mechanism mediated by a decrease in IL-5 secretion by CD4-positive lymphocytes.

The effect of vitamin E-bonded dialyzer membrane on red blood cell survival in hemodialyzed patients

Reduced red blood cell (RBC) survival due to oxidative damage is one of the causes of anemia in patients under long-term hemodialysis. Recently, it has been shown that vitamin E-bonded dialyzer membrane is able to reduce the oxidative stress during hemodialysis. In humans, creatine content in RBC is used to measure RBC life span and erythropoietic capacity, since it rapidly declines as the RBCs become old. Therefore this study aimed to elucidate the effect of vitamin E-bonded dialyzer membrane on RBC life span by measuring creatine content in RBC.

Effect of vitamin E modified cellulose membrane on human lymphocyte, monocyte, and granulocyte CD11b/CD18 adhesion molecule expression during hemodialysis

Chronic renal failure induces a clinical state of immunodefi ciency that also depends upon a wide spectrum of dialysis membranes used during hemodialysis. Previous studies have shown that cellular immunodeficiency is caused by malfunc tion of the antigen presenting cells (monocytes or granulocytes). Subsequent activation of rolling mononuclear leuko cytes results in up-regulated expression of CD11b/CD18 (Mac-1) on endothelial cells. It is postulated that a VitE coated dialysis membrane might minimize the membrane biocompatibility, thereby generating a smaller amount of re active oxygen species (ROS). The purpose of this study was to evaluate the expression of the CD11b/CD18 adhesion mole cule on lymphocytes, monocytes, and granulocytes during HD in 10 patients, using flow cytometric analysis. The study protocol included the measurement of molecule expression using cellulose membrane (Clirans RS15, TERUMO Corp. Japan), and the same membrane coated by vitamin E (Exce brane, Clirans E15, TERUMO Corp., Japan) during 20 dialysi sessions each. Lymphocyte CD11 b/CD1 8 (Mac-1) expression did not change with either dialyzer type. However, monocyt (p = 0.046) and granulocyte (p = 0.018) CD11b/CD18 ex pression in the post HD period was significantly lower using the vitamin E coated membrane compared with the contro cellulose membrane. Our findings suggest a significant de crease in activation and migration of monocytes and granu locytes when using a vitamin E coated cellulose membrane.

Non-traditional cardiovascular disease risk factors in end-stage renal disease: oxidate stress and hyperhomocysteinemia

Studies in experimental animals have shown that oxidative stress and hyperhomocyst(e)inemia culminate in abnormal vascular and endothelial regulation, functional nitric oxide deficiency, vascular hypertrophy, and atherosclerosis. Oxidative stress is accompanied by increased advanced glycation endproducts and oxidized low density lipoproteins. Studies of patients with end-stage renal disease provide extensive indirect, evidence of increased oxidative stress and more than ninety percent are hyperhomocyt(e)inemic. Presently, only uncontrolled or observational studies are available to assess the effects of anti-oxidant therapy for oxidative stress or folate therapy for hyperhomocyst(e)inemia in these patients. Promising developments include the reports of beneficial effects of a vitamin E coated dialyzer, and the reduction in homocyst(e)ine levels in patients with end-stage renal disease given an intravenous folate metabolite. However, there is presently no therapy available to reverse fully oxidative stress or hyperhomocyst(e)inemia. Therefore, the causative role of these nontraditional risk factors of cardiovascular disease remains untested.