Aminolysis-Based Zwitterionic Immobilization on Polyethersulfone Membranes for Enhanced Hemocompatibility: Experimental, Computational, and Ex Vivo Investigations

Dialysis membranes are not hemocompatible with human blood, as the patients are suffering from the blood-membrane interactions' side effects. Zwitterionic structures have shown improved hemocompatibility; however, their complicated synthesis hinders their commercialization. The goal of the study is to achieve fast functionalization for carboxybetaine and sulfobetaine zwitterionic immobilization on PES membranes while comparing the stability and the targeted hemocompatibility. The chemical modification approach is based on an aminolysis reaction. Characterization, computational simulations, and clinical analysis were conducted to study the modified membranes. Atomic force microscopy (AFM) patterns showed a lower mean roughness for carboxybetaine-modified (6.3 nm) and sulfobetaine-modified (7.7 nm) membranes compared to the neat membrane (52.61 nm). The pore size of the membranes was reduced from values above 50 nm for the neat PES to values between 2 and 50 nm for zwitterionized membranes, using Brunauer-Emmett-Teller (BET) analysis. More hydrophilic surfaces led to a growth equilibrium water content (EWC) of nearly 6% for carboxybetaine and 10% for sulfobetaine-modified membranes. Differential scanning calorimetry (DSC) measurements were 12% and 16% stable water for carboxybetaine- and sulfobetaine-modified membranes, respectively. Sulfobetaine membranes showed better compatibility with blood with respect to C5a, IL-1a, and IL-6 biomarkers. Aminolysis-based zwitterionization was found to be suitable for the improvement of hemodialysis membranes. The approach introduced in this paper could be used to modify the current dialysis membranes with minimal change in the production facilities.

Platelets in Renal Disease

Kidney disease is a major global health concern, affecting millions of people. Nephrologists have shown interest in platelets because of coagulation disorders caused by renal diseases. With a better understanding of platelets, it has been found that these anucleate and abundant blood cells not only play a role in hemostasis, but also have important functions in inflammation and immunity. Platelets are not only affected by kidney disease, but may also contribute to kidney disease progression by mediating inflammation and immune effects. This review summarizes the current evidence regarding platelet abnormalities in renal disease, and the multiple effects of platelets on kidney disease progression. The relationship between platelets and kidney disease is still being explored, and further research can provide mechanistic insights into the relationship between thrombosis, bleeding, and inflammation related to kidney disease, and elucidate targeted therapies for patients with kidney disease.

The Characteristics of Dialysis Membranes: Benefits of the AN69 Membrane in Hemodialysis Patients

Patients undergoing hemodialysis (HD) experience serious cardiovascular complications, through malnutrition, inflammation, and atherosclerosis. Amputation for peripheral arterial disease (PAD) is more prevalent in patients undergoing HD than in the general population. In addition, revascularization procedures in dialysis patients are often associated with subsequent amputation and high mortality rates. To improve the prognosis of dialysis patients, malnutrition and inflammation must be properly treated, which necessitates a better understanding of the characteristics of dialysis membranes. Herein, the characteristics of several dialysis membranes were studied, with a special reference to the AN69 membrane, noting several similarities to low-density lipoprotein (LDL)-apheresis, which is also applicable for the treatment of PAD. Both systems (LDL-apheresis and AN69) have anti-inflammatory and anti-thrombogenic effects because they use a negatively charged surface for extracorporeal adsorptive filtration from the blood/plasma, and contact phase activation. The concomitant use of both these therapeutic systems may have additive therapeutic benefits in HD patients. Here, we reviewed the characteristics of dialysis membranes and benefits of the AN69 membrane in dialysis patients.

Impact of intradialytic fiber clotting on dialyzer extraction and solute removal: a randomized cross-over study

Previous studies revealed the importance of biocompatibility, anticoagulation strategy, and dialysis mode and duration on fiber blocking at the end of a hemodialysis session. The present study was set up in ten hemodialysis patients to relate fiber patency to dialyzer extraction and removal of small and middle molecules. With only 1/4th of the regular anticoagulation dose, and using a Solacea 19H and FX800 CorDiax dialyzer, fiber patency was quantified using 3D micro-CT scanning for different dialysis durations (i.e. 60, 120 and 240 min). While Solacea showed enhanced fiber patency in all test sessions, fiber blocking in the FX800 CorDiax did not follow a linear process during dialysis, but was rather accelerated near the end of dialysis. Dialyzer extraction ratios were correlated with the percentages of open fibers. While the fiber blocking process affected extraction ratios (i.e. for phosphorus and myoglobin in the FX800 CorDiax), it had only minor impact on the removal of toxins up to at least 12 kDa.

Secondary Immunodeficiency Related to Kidney Disease (SIDKD)-Definition, Unmet Need, and Mechanisms

Kidney disease is a known risk factor for poor outcomes of COVID-19 and many other serious infections. Conversely, infection is the second most common cause of death in patients with kidney disease. However, little is known about the underlying secondary immunodeficiency related to kidney disease (SIDKD). In contrast to cardiovascular disease related to kidney disease, which has triggered countless epidemiologic, clinical, and experimental research activities or interventional trials, investments in tracing, understanding, and therapeutically targeting SIDKD have been sparse. As a call for more awareness of SIDKD as an imminent unmet medical need that requires rigorous research activities at all levels, we review the epidemiology of SIDKD and the numerous aspects of the abnormal immunophenotype of patients with kidney disease. We propose a definition of SIDKD and discuss the pathogenic mechanisms of SIDKD known thus far, including more recent insights into the unexpected immunoregulatory roles of elevated levels of FGF23 and hyperuricemia and shifts in the secretome of the intestinal microbiota in kidney disease. As an ultimate goal, we should aim to develop therapeutics that can reduce mortality due to infections in patients with kidney disease by normalizing host defense to pathogens and immune responses to vaccines.

Recent advances in dialysis membranes

PURPOSE OF REVIEW

Improvement in hemodialysis treatment and membrane technology are focused on two aims: the first one is to achieve a better control of circulating uremic solutes by enhancing removal capacity and by broadening molecular weight spectrum of solutes cleared; the second one is to prevent inflammation by improving hemocompatibility of the global dialysis system.

RECENT FINDINGS

Despite impressive progresses in polymers chemistry few hazards are still remaining associated with leaching or sensitization to polymer additives. Research has focused on developing more stable polymers by means of additives or processes aiming to minimize such risks. Membrane engineering manufacturing with support of nanocontrolled spinning technology has opened up membrane to middle and large molecular weight substances, while preserving albumin losses. Combination of diffusive and enhanced convective fluxes in the same hemodialyzer module, namely hemodiafiltration, provides today the highest solute removal capacity over a broad spectrum of solutes.

SUMMARY

Dialysis membrane is a crucial component of the hemodialysis system to optimize solute removal efficacy and to minimize blood membrane biological reactions. Hemodialyzer is much more than a membrane. Dialysis membrane and hemodialyzer choice are parts of a treatment chain that should be operated in optimized conditions and adjusted to patient needs and tolerance, to improve patient outcomes.

Soluble Triggering Receptor on Myeloid Cell-1 and its Predictive Factors in Patients With End-Stage Kidney Disease on Hemodialysis

Triggering receptor expressed on myeloid cells (TREM)-1 is a potent and early amplifier of the inflammatory response expressed on neutrophils and monocytes/macrophages. TREM-1, and its soluble form (sTREM-1), are increased in sepsis and other noninfectious inflammatory conditions. However, virtually no data are available in kidney disease. To determine serum sTREM-1 and its associated variables in patients on hemodialysis (HD), cross-sectional study including 264 HD patients and 148 controls. sTREM-1 was measured by quantitative sandwich enzyme immunoassay; soluble tumor necrosis factor receptor-1 (sTNF-R1), interleukin-6 (IL-6), and C-reactive protein (CRP) were also measured. All inflammation markers were significantly higher in HD patients than controls. Median (IQR) sTREM-1 was 1,006 (613-1,650) pg/mL but undetectable in controls. Considering only HD patients, sTREM-1 was positively correlated with IL-6 (r = 0.19, p = 0.008), and its levels were significantly higher in patients with arteriovenous fistula than in those with temporary catheter (1,226 vs. 743 pg/mL), in patients with 3 HD sessions/week than in those with 2 sessions/week (1,150 vs. 646 pg/mL), and in patients with >1 year on HD than in those with ≤1 year (1,100 vs. 948 pg/mL), whereas they were not different regarding age or presence of infection. Serum sTREM-1, sTNF-R1, IL-6, and CRP were higher in HD patients compared to controls. In HD patients, sTREM-1 displayed higher levels in individuals with arteriovenous fistula, 3 sessions/week and longer vintage, but not in those with infection or older age; in multivariate analysis, only the first two variables significantly predicted higher sTREM-1 levels.

Amelioration of hemodialysis-induced oxidative stress and fatigue with a hemodialysis system employing electrolyzed water containing molecular hydrogen

Background

A novel hemodialysis (HD) system employing electrolyzed water containing molecular hydrogen (E-HD) has been developed to improve the bio-compatibility of HD. This study examined the impact of E-HD on changes in redox state during HD and HD-related fatigue.

Method

This single-arm, prospective observational study examined 63 patients on chronic HD (41 males; mean age, 72 ± 9 years; median duration of HD, 7 years). Redox parameters (serum myeloperoxidase [MPO], malondialdehyde-protein adduct [MDA-a], thioredoxin 1 [TRX]) during HD were compared between control HD (C-HD) and E-HD after 8 weeks. Fatigue was evaluated using a numerical rating scale (NRS) during the 8-week course.

Results

In C-HD, an increase in serum MPO accompanied increases in both oxidative products (MDA-a) and anti-oxidant molecules (TRX). In E-HD, although increases in MPO were accentuated during HD, changes in MDA-a and TRX were ameliorated as compared with C-HD. In patients who showed HD-related fatigue (47%) during C-HD, change in MDA-a by HD was a risk factor for the presence of fatigue. During the 8 weeks of observation on E-HD, those patients displayed significant decreases in fatigue scores.

Conclusion

E-HD ameliorates oxidative stress and supports anti-oxidation during HD, suggesting improved bio-compatibility of the HD system. E-HD may benefit patients with HD-related fatigue, but the mechanisms underlying changes to oxidative stress have yet to be clarified.

Clinical hemocompatibility of double-filtration lipoprotein apheresis comparing polyethersulfone and ethylene-vinyl alcohol copolymer membranes

Activation of the complement system and leukocytes by blood-membrane interactions may further promote arteriosclerosis typically present in patients on lipoprotein apheresis. As clinical data on the hemocompatibility of lipoprotein apheresis are scarce, a controlled clinical study comparing two different types of plasma separation and fractionation membranes used in double-filtration lipoprotein apheresis was urgently needed, as its outcome may influence clinical decision-making. In a prospective, randomized, crossover controlled trial, eight patients on double-filtration lipoprotein apheresis were subjected to one treatment with recent polyethersulfone (PES) plasma separation and fractionation membranes and one control treatment using a set of ethylene-vinyl alcohol copolymer (EVAL) membranes. White blood cell (WBC) and platelet (PC) counts, complement factor C5a and thrombin-antithrombin III (TAT) concentrations were determined in samples drawn at defined times from different sites of the extracorporeal blood and plasma circuit. With a nadir at 25 minutes, WBCs in EVAL decreased to 33.5 ± 10.7% of baseline compared with 63.8 ± 22.0% at 20 minutes in PES (P < .001). The maximum C5a levels in venous blood reentering the patients were measured at 30 minutes, being 30.0 ± 11.2 µg/L with EVAL and 12.3 ± 9.0 µg/L with PES (P < .05). The highest C5a concentrations were found in plasma after the plasma filters (EVAL 56.1 ± 22.0 µg/L at 15 minutes vs PES 23.3 ± 15.2 µg/L at 10 minutes; P < .001). PC did not significantly decrease over time with both membrane types, whereas TAT levels did not rise until the end of the treatment without differences between membranes. Regarding lipoprotein(a) and low-density lipoprotein (LDL) cholesterol removal, both membrane sets performed equally. Compared with EVAL, PES membranes cause less leukocyte and complement system activation, the classical parameters of hemocompatibility of extracorporeal treatment procedures, at identical treatment efficacy. Better hemocompatibility may avoid inflammation-promoting effects through blood-material interactions in patients requiring double-filtration lipoprotein apheresis.

Immunological Alterations due to Hemodialysis Might Interfere with Early Complications in Renal Transplantation

BACKGROUND

Chronic or intercurrent alterations of the immune system in patients with end-stage renal disease (CKD) and intermittent hemodialysis (CKD5D, HD) have been attributed to an acute rejection of renal allograft.

METHODS

Leukocyte subsets in flow cytometry, complement activation, and concentrations of TGFβ, sCD30 (ELISA), and interleukins (CBA) of fifteen patients eligible for renal transplantation were analyzed before, during, and after a regular HD.

RESULTS

Before HD, the median proportion of CD8+ effector cells, CD8+ CCR5+ effector cells, and HLA-DR+ regulatory T cells as well as the median concentration of soluble CD30 increased and naive CD8+ T cells decreased. During HD, there was a significant decrease in CD4- CD8- T cells (p < 0.001) and an increase in CD25+ T cells (p = 0.026), sCD30 (p < 0.001), HLA-DR+ regulatory T cells (p = 0.005), and regulatory T cells (p = 0.003). TGFβ and sCD30 increased significantly over time. The activity of the classical complement pathway started to slightly increase after the first hour of HD and lasted until fifteen minutes after finishing dialysis. The decrease in the functional activity of the alternative pathway was only transient and was followed by a significant increase within 15 minutes after finishing the treatment.

CONCLUSION

HD might interact with the allograft outcome by influencing T cell subsets and activation of the complement system in a biphasic course.

Assessment of physical performance and body composition in male renal transplant patients

BACKGROUND

Renal transplant (RTX) recipients seem to experience a better quality of life compared to dialysis patients. However, the factors responsible for this positive effect are not completely defined. Conceivably, a change in the physical performance of these patients could play a role.

METHODS

To assess this, we measured: (1) waist circumference, fat mass and appendicular fat-free mass (aFFM) by dual-energy X-ray densitometry, (2) physical performance with the Short Physical Performance Battery, and (3) muscle strength with the handgrip test, in 59 male RTX, 11 chronic kidney disease in conservative treatment (CKD) and 10 peritoneal dialysis (PD) patients.

RESULTS

Surprisingly, anthropometric characteristics and body composition were similar among the three groups. However, despite a low aFFM, muscle strength was higher in stable RTX recipients > 5 years after transplantation than in dialyzed patients. Instead, CKD (wait-listed for RTX) had similar muscle strength to RTX patients. Waist circumference in RTX recipients showed a redistribution of body fat with increased central adipose tissue allocation compared to PD. At linear regression analysis, age, weight, height, aFFM, hemoglobin and transplant age were independent predictors of handgrip strength, explaining about 37% of the variance. Age and transplant age accounted for 18 and 12% of variance, respectively.

CONCLUSIONS

Our study demonstrates, for the first time, that clinically stable RTX recipients have greater muscle strength than dialyzed patients and suggests that the handgrip test could be an effective and easy-to-perform tool to assess changes in physical performance in this large patient population.

Chronic kidney disease induces inflammation by increasing Toll-like receptor-4, cytokine and cathelicidin expression in neutrophils and monocytes

TLR expression in neutrophils and monocytes is associated with increased cytokine synthesis, resulting in increased inflammation. However, the inflammatory pathway related to TLR and cathelicidin expression in these cells from CKD patients is unclear. To evaluate TLR4, cathelicidin, TNF-α, IL-6, IL-10 and MCP-1 expression in neutrophils and monocytes from HD and CKD patients. Blood samples were drawn from 47 CKD and 43 HD patients and 71 age and gender-matched healthy volunteers (CONT). TLR4 was analyzed using flow cytometry. Cathelicidin, TNF-α, IL-6, IL-10 and MCP-1 were analyzed via ELISA.TLR4 expression in neutrophils was higher in HD patients than in stage 3 and 4 CKD patients. In these cells, we observed a positive correlation between TLR4 and cathelicidin, TNF-α, IL-6, IL-10 and MCP-1 levels. In monocytes, TLR4 expression was significantly higher in CKD 3 and 4 groups than in the control and HD groups and positively and negatively correlated with IL-6 and MCP-1 and cathelicidin, respectively. TNF-α, IL-6 and MCP-1 serum levels were higher in HD and CKD patients than in control. Cathelicidin and IL-10 levels were only higher in HD patients. IL-6 serum levels were positively correlated with all cytokines, and cathelicidin was negatively correlated with MCP-1 (r = - 0.35; p < 0.01) and positively correlated with IL-10 (r = 0.37; p = 0.001). These results suggest that a uremic environment induces high TLR4, cathelicidin and cytokine expression and may increase inflammation. Thus, future studies should be conducted to evaluate whether TLR4 and cathelicidin should be targets for anti-inflammatory therapeutic strategies.

Pregnancy-Associated Plasma Protein a during Hemodialysis with Polyamide and Diacetate Cellulosic Membranes

Pregnancy-associated plasma protein A (PAPP-A) is a new prognostic factor of acute coronary syndrome in the general population. It is elevated in hemodialysis (HD) patients and at baseline, it was shown to be related to inflammation and oxidative stress. The aim of the study was to examine the relationship of PAPP-A and oxidative stress and inflammatory markers to HD treatment. Studied parameters were determined in 10 chronic HD patients treated with low flux polyamide (1st session) and diacetate cellulosic membranes (2nd session) at the beginning, after 15 minutes and at the end of the dialysis session. TRACE method (Time Resolved Amplified Cryptate Emission) was used for PAPP-A assessment. Results were evaluated with ANOVA.

PAPP-A levels did not depend on the type of HD membrane but changed significantly with the time of the HD session. They increased significantly from the beginning of HD to 15 min and then decreased to the end of the HD session – p<0.05 15 min of HD vs start, p<0.01 end vs start, p<0.0001 end vs 15 min of HD for polyamide membrane and p=0.05 15 min of HD vs start, p<0.01 end vs start, p<0.0001 end vs 15 min of HD for diacetate cellulosic membrane. Changes in other parameters and differences between membranes were only minimal.

We can conclude that PAPP-A as a marker of cardiovascular damage shows significant changes during the HD session. Its initial increase might be ascribed to its release from complexes or storage. During dialysis, it might be destroyed or cleaved and removed as free fragments. Its levels both before and after the HD session are higher than in healthy subjects.

Preventive Effect of α-Tocopherol and Glycyrrhizin against Platelet-Neutrophil Complex Formation Induced by Hemodialysis Membranes

Background

The intradialytic activation of leukocytes is a major cause of hemodialysis (HD)-associated complications. Contact between blood and HD membranes frequently induces the formation of microaggregates composed of activated platelets and leukocytes, causing leukocyte activation that includes the generation of reactive oxygen species (ROS). This complex formation is mediated primarily by the interaction between P-selectin on activated platelets and its counter-ligands on leukocytes.

Objective

We examined the preventive effects of α-tocopherol and glycyrrhizin in vitro against platelet-neutrophil microaggregate formation and neutrophil ROS production induced by HD membranes.

Methods and Results

Microaggregate formation induced by the incubation of heparinized whole blood with polysulfone (PS) HD membranes was effectively inhibited by α-tocopherol and glycyrrhizin. α-Tocopherol, but not glycyrrhizin, was found to inhibit PS membrane-induced P-selectin expression on the platelet surface; however, glycyrrhizin did inhibit both the formation of neutrophil-platelet microaggregates induced by adenosine diphosphate (ADP) and the adhesion of HL60 leukemic cells to P-selectin-expressing Chinese hamster ovary (CHO) cells, suggesting that glycyrrhizin acts as a competitive inhibitor of P-selectin-mediated cell adhesion. Finally, these compounds almost completely abrogated PS membrane-induced and platelet-dependent ROS production by neutrophils.

Conclusions

These results suggest that α-tocopherol and glycyrrhizin may function as preventive agents of HD-associated leukocyte activation though the modulation of platelet-leukocyte interaction.

Clinical and hematological data to group different chronic kidney disease patients: A practical approach to establish different groups of patients

BACKGROUND

Chronic kidney disease (CKD) is the convergent point of several pathological processes, and its evolution is insidious and characterized by a progressive and irreversible loss of kidney function. This impaired function induces the accumulation of uremic toxins and individuals with terminal CKD often have altered physiological responses, including a persistent state of immuno-suppression and development of diseases. A better characterization and stratification of these patients with CKD in different immuno-compromised groups would contribute to more effective and personalized treatments. The focus of this study was to use two parameters to stratify patients with CKD into four separate groups that are representative of different immunological status.

METHODS

Patients with CKD were chosen randomly and stratified into four separate groups according to the period of time receiving dialysis treatment and leukocyte blood counts. The amount of apoptotic CD4 T cells were measured in each group of patients, and clinical/hematological parameters were correlated by multivariate analysis with each group.

RESULTS

Observations reveal that one of the four groups of patients with CKD (group 3) had more apoptotic CD4 T cells than the other group; this group also had an increased malnutrition inflammation score (MIS), an elevated Kt/V, and a higher incidence of smoking.

CONCLUSION

A simple two-parameter-based stratification strategy could be used to design effective immunological therapies that differentiate the degrees of immuno-suppression across groups of patients with CKD.

Development of functionalized polyetherimide/polyvinylpyrrolidone membranes for application in hemodialysis

The present study aimed to synthesize membranes for hemodialysis based on polyetherimide (PEI) and polyvinylpyrrolidone (PVP), with chemical immobilization of heparin on its surface to increase blood compatibility. The synthesized PEI/PVP membranes were characterized by morphological analysis and transport properties, as well by infrared spectroscopy (FT-IR), protein adsorption, contact angle, activated partial thromboplastin time (aPTT), and platelet adhesion. Hydraulic permeability of the synthesized PEI membranes were comparable to those of current high flux clinical membranes; values of diffusive permeability and rejection for typical solutes were similar to those reported in literature. The immobilization of heparin, in turn, resulted in more hydrophilic membranes, with insignificant protein adsorption and platelet adhesion (as opposed to actual clinical membranes), indicating anti-thrombogenic characteristics as confirmed by increased aPTT.

Cardiovascular disease in haemodialysis: role of the intravascular innate immune system

Haemodialysis is a life-saving renal replacement modality for end-stage renal disease, but this therapy also represents a major challenge to the intravascular innate immune system, which is comprised of the complement, contact and coagulation systems. Chronic inflammation is strongly associated with cardiovascular disease (CVD) in patients on haemodialysis. Biomaterial-induced contact activation of proteins within the plasma cascade systems occurs during haemodialysis and initially leads to local generation of inflammatory mediators on the biomaterial surface. The inflammation is spread by soluble activation products and mediators that are generated during haemodialysis and transported in the extracorporeal circuit back into the patient together with activated leukocytes and platelets. The combined effect is activation of the endothelium of the cardiovascular system, which loses its anti-thrombotic and anti-inflammatory properties, leading to atherogenesis and arteriosclerosis. This concept suggests that maximum suppression of the intravascular innate immune system is needed to minimize the risk of CVD in patients on haemodialysis. A potential approach to achieve this goal is to treat patients with broad-specificity systemic drugs that target more than one of the intravascular cascade systems. Alternatively, 'stealth' biomaterials that cause minimal cascade system activation could be used in haemodialysis circuits.

Renal Function Replacement by Hemodialysis: Forty-Year Anniversary and a Glimpse into the Future at Hand

From its introduction in 1943 and until the late 1970s, hemodialysis (HD) has been a lengthy and cumbersome treatment administered by a few skilled physicians and technicians to a very limited number of terminal kidney patients. The technological innovations introduced over the years made HD a treatment administered and supervised by nursing personnel to a very large numbers of kidney patients, hopefully until recovery of kidney functions or kidney transplantation. In 2013, it is estimated that 2.250.00 kidney patients were treated worldwide, and their number is steadily increasing. Shortage of transplant kidneys and quality of current treatments has contributed to increasing the survival of HD patients. Today, it is not unusual to find patients who have been on HD for longer than twenty years. All this generated the feeling that performance of membranes and dialysis technology has reached its limit. Recently, the increasing economic burden of healthcare caused by people ageing and the increasing incidence of degenerative diseases (e.g. diabetes and cardiovascular diseases), and the economic crisis has pushed many governments and health insurances to cut resources for healthcare. The main consequence is that investments in research and development in HD have been significantly reduced. The question is whether there is indeed no need for innovation in HD.

In this paper, it is discussed how the paradigm of HD has changed and what possibly are now the drivers for innovation in HD. A few ideas are proposed that could be developed by adapting existing technologies to the future needs of HD.

Technology innovation for patients with kidney disease

The loss of kidney function is a life-changing event leading to life-long dependence on healthcare. Around 5000 people are diagnosed with kidney failure every year. Historically, technology in renal medicine has been employed for replacement therapies. Recently, a lot of emphasis has been placed on technologies that aid early identification and prevent progression of kidney disease, while at the same time empowering affected individuals to gain control over their chronic illness. There is a shift in diversity of technology development, driven by collaborative innovation initiatives such the National Institute's for Health Research Healthcare Technology Co-operative for Devices for Dignity. This has seen the emergence of the patient as a key figure in designing technologies that are fit for purpose, while business involvement has ensured uptake and sustainability of these developments. An embodiment of this approach is the first successful Small Business Research Initiative in the field of renal medicine in the UK.

Low Serum Neutrophil Gelatinase-associated Lipocalin Level as a Marker of Malnutrition in Maintenance Hemodialysis Patients

Background

Neutrophil gelatinase-associated lipocalin (NGAL or LCN2) is an iron-transporting factor which possesses various activities such as amelioration of kidney injury and host defense against pathogens. Its circulating concentrations are elevated in acute and chronic kidney diseases and show a positive correlation with poor renal outcome and mortality, but its clinical significance in maintenance hemodialysis (HD) patients remains elusive.

Methods

Serum NGAL levels were determined by enzyme-linked immunosorbent assay in out-patient, Japanese HD subjects. Their correlation to laboratory findings and morbidity (as development of severe infection or serum albumin reduction) was investigated using linear regression analysis and χ² test.

Results

Pre-dialysis serum NGAL levels in HD patients were elevated by 13-fold compared to healthy subjects (n=8, P<0.001). In a cross-sectional study of 139 cases, serum NGAL concentrations were determined independently by % creatinine generation rate (an indicator of muscle mass, standardized coefficient β=0.40, P<0.001), peripheral blood neutrophil count (β=0.38, P<0.001) and anion gap (which likely reflects dietary protein intake, β=0.16, P<0.05). Iron administration to anemic HD patients caused marked elevation of peripheral blood hemoglobin, serum ferritin and iron-regulatory hormone hepcidin-25 levels, but NGAL levels were not affected. In a prospective study of 87 cases, increase in serum albumin levels a year later was positively associated to baseline NGAL levels by univariate analysis (r=0.36, P<0.01). Furthermore, within a year, patients with the lowest NGAL tertile showed significantly increased risk for marked decline in serum albumin levels (≥0.4 g/dl; odds ratio 5.5, 95% confidence interval 1.5–20.3, P<0.05) and tendency of increased occurrence of severe infection requiring admission (odds ratio 3.1, not significant) compared to the middle and highest tertiles.

Conclusion

Low serum NGAL levels appear to be associated with current malnutrition and also its progressive worsening in maintenance HD patients.

An intradialytic increase in serum interleukin-6 levels is associated with an increased mortality in hemodialysis patients

BACKGROUND

The inflammatory marker interleukin-6 (IL-6) increases early in the inflammatory cascade. The aim of this study was to evaluate whether an increase in serum IL-6 levels during a hemodialysis (HD) session is associated with mortality.

METHODS

57 adult patients treated with HD for more than 1 month were prospectively studied over a 3-year follow-up period. Demographic and clinical data were collected and blood samples were drawn before and after a midweek HD session. Events of death and censoring were recorded.

RESULTS

During the 3-year follow-up, 50.8% of the patients died. In univariate Cox regression analysis, an increase in IL-6 levels during HD was associated with an increased mortality (HR 1.41 per pg/ml; 95% CI 1.06 to 1.88; P = .017). In multivariate Cox models, the only independent predictors of all-cause mortality were: an increase in IL-6 levels during dialysis (HR 1.46 per pg/ml; 95% CI 1.08 to 1.98; P = .014), higher baseline C-reactive protein (CRP) levels and older age. When predictors of an increase in serum IL-6 levels during HD were introduced into the model, mortality was still significantly associated with IL-6 elevation during dialysis (HR 1.47 per pg/ml, 95% CI 1.01 to 2.14; P = .045).

CONCLUSIONS

A rise in serum IL-6 levels during a single HD session is associated with a higher mortality among HD patients, independent of predialysis CRP or IL-6 levels. The results may imply the presence of an intradialytic inflammatory response that affects survival in HD patients.

Biocompatibility assessment of haemodialysis membrane materials by proteomic investigations

We examine and compare the protein adsorption capacity and coagulation profiles of different haemodialysis membrane biomaterials.

Assessment of hemodialysis impact by Polysulfone membrane on brain plasticity using BOLD-fMRI

PURPOSE

Hemodialysis (HD) is considered the most common alternative for overcoming renal failure. Studies have shown the involvement of HD membrane in the genesis of oxidative stress (OS) which has a direct impact on the brain tissue and is expected to be involved in brain plasticity and also reorganization of brain function control. The goal of this paper was to demonstrate the sensitivity of the blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) to characterize the OS before and after the HD session.

PATIENTS, MATERIALS AND METHODS

Twelve male patient-volunteers following chronic HD for more than 6months were recruited among 86 HD-patients. All patients underwent identical assessment immediately before and after the full HD-session. This consisted of full biological assessment, including malondialdehyde (MDA) and total antioxidant activity (TAOA); and brain BOLD-fMRI using the motor paradigm in block-design.

RESULTS

Functional BOLD-fMRI maps of motor area M1 were obtained from the HD patient before and after the hemodialysis session, important decrease in the intensity of brain activation of the motor area after HD, and important increase of the size of the volume of brain activation were observed, these changes are reflecting brain plasticity that is well correlated to OS levels. Individual patients MDA and TAOA before and after the hemodialysis sessions demonstrated a clear and systematic increase of the OS after HD (P-value=0.03). Correlation of BOLD-fMRI maximal signal intensity and volume of activated cortical brain area behaviors to MDA and total TAOA were close to 1.

CONCLUSION

OS is systematically increased in HD-patients after the HD-process. Indeed, the BOLD-fMRI shows a remarkable sensitivity to brain plasticity studied cortical areas. Our results confirm the superiority of the BOLD-fMRI quantities compared to the biological method used for assessing the OS while not being specific, and reflect the increase in OS generated by the HD. BOLD-fMRI is expected to be a suitable tool for evaluating the plasticity process evolution in hemodialysis brain patients.

Effect of Indoxyl Sulfate on Oxidative Stress, Apoptosis, and Monocyte Chemoattractant Protein-1 in Leukocytes

This study showed that indoxyl sulfate, an uremic toxin present in the serum of patients with chronic kidney disease, increases oxidative stress and apoptosis in human neutrophils and reduces the production of monocyte chemoattractant protein-1 (MCP-1) by peripheral blood mononuclear cell (PBMC). It is possible that these effects caused by this toxin contribute to vascular injury of the endothelium and decreased response to infectious insults, respectively.

Effects of treatment in the levels of circulating cytokines and growth factors in cystic fibrosis and dialyzed patients by multi-analytical determination with a biochip array platform

Chronic inflammatory diseases need non-invasive sensitive, reliable and predictive clinical biomarkers for diagnosis and monitoring therapy. Since inflammation is a complex phenomenon, simultaneous evaluation of different analytes in the same sample may help in defining this complexity and in developing specific anti-inflammatory intervention strategies. In this study, we used a biochip array system capable of measuring 12 cytokines and growth factors (IL-2, IL-4, IL-6, IL-8, IL-10, IL-1 α, IL-1 β, IFN-γ, TNF-α, MCP-1, VEGF, and EGF) in three groups: 97 control subjects; 24 cystic fibrosis (CF) patients before and during the antibiotic treatment (6 and 15days) for acute pulmonary exacerbation as well as 15days after the withdrawal of therapy; 22 children and young adults on chronic hemodialysis (HD) at the beginning and at the end of a standard HD session. CF patients in acute exacerbation displayed higher IL-2, IL-6, VEGF and MCP-1 levels than the control subjects. IL-6 significantly decreased during therapy (P<0.01) but not 15days after the withdrawal of therapy. IL-8 and EGF levels were significantly lower after 15days from the interruption of therapy (P<0.05 and P<0.01 respectively). Regression analysis showed that IL-4 and IL-6 correlated with the amelioration of the respiratory function during therapy. Patients on HD displayed higher IL-6 but lower IL-2, IL-4, IL-8, IFN-γ and EGF levels than control subjects. Serum levels of IL-8, IL-10 and IFN-γ were significantly higher at the end of the HD session (P<0.05 for all three). A biochip array allowed to define a pattern of cytokines/growth factors associated with an acute exacerbation in CF patients and IL-4 and IL-6 as predictors of response to therapy. In younger HD patients, we identified a biomarker pattern which is different from that of older patients. Finally, further studies are warranted to examine the role of these biomarkers in the pathogenesis of complications in HD patients.

Plasminogen activator inhibitor-1 in kidney pathology (Review)

Plasminogen activator inhibitor type-1 (PAI-1) inhibits tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), which convert plasminogen to plasmin, a strong proteolytic enzyme. Thus, PAI-1 is a primary and negative regulator of plasmin-driven proteolysis. In addition to its main role as an inhibitor of fibrinolysis, PAI‑1 has been implicated as a mediator in other processes, including fibrosis, rheumatoid arthritis, atherosclerosis, tumor angiogenesis and bacterial infections. It also significantly modulates cellular adhesion or migration, wound healing, angiogenesis and tumor cell metastasis. However, in the present study, we have reviewed the literature in relation to different kidney diseases where PAI-1 regulates fibrinolysis and acts independently of proteolysis. PAI-1 is normally produced in trace amounts in healthy kidneys but is synthesized in a wide variety of both acute and chronic diseased kidneys. We reviewed the role of PAI-1 in diabetic kidney nephropathy, chronic kidney disease, hemodialysis, peritoneal dialysis and in kidney transplantation. Increased PAI-1 expression results in accumulation of extracellular matrix (ECM) leading to numerous kidney diseases. Predisposition to some diseases is due to the genetic role of PAI-1 in their development. A number of studies demonstrated that the inhibition of PAI-1 activity or therapy with a mutant PAI-1 increases matrix turnover and reduces glomerulosclerosis by competing with endogenous PAI-1. This strongly suggests that PAI-1 is a valid target in the treatment of fibrotic renal disease. However, net proteolytic activity depends on the delicate balance between its negative regulation by PAI-1 and activation by uPA and tPA. Also, plasmin activated by its inhibitors upregulates activity of other enzymes. Thus, assessment of prognosis for the diseased kidney should include a variety of proteolysis regulators and enzymes.

Detection of neutralizing antibodies to erythropoietin by inhibition of rHuEPO-stimulated EGR1 gene expression in the UT-7/EPO cell line

Recombinant erythropoietin (rHuEPO) is used extensively to treat anaemia associated with chronic kidney disease. However, the development of neutralizing antibodies (NAbs) to rHuEPO can result in the development of antibody-mediated pure red cell aplasia (PRCA). The detection of NAb in patient sera by in vitro bioassay relies on the inhibition of a cellular response to rHuEPO. Current bioassays for rHuEPO measure proliferation in responsive cell lines such as the erythroleukaemic cell lines, UT-7 and UT-7/EPO, the latter sensitized to EPO. Using these cell lines, we show the dose-responsive induction of both PIM1 and EGR1 gene expression in UT-7 cells and of EGR1 in UT-7/EPO cells. The expression of EGR1 in UT-7/EPO cells in response to rHuEPO was comparable to the proliferative response measured by (3)H-thymidine incorporation and could be inhibited by serum from a patient with NAb-mediated PRCA in a dilution-dependent manner. Bioassays based on the induction of endogenous gene expression are comparable to current bioassays but are considerably quicker given that incubation time is decreased from 2-3 days to 50 min. Measurement of EGR1 gene expression in response to rHuEPO in UT-7/EPO cells offers a rapid, non-radioactive and automatable alternative to current assays for the detection of rHuEPO NAbs.

Prevalence of circulating CD4+CD28null T cells is associated with early atherosclerotic damage in patients with end-stage renal disease undergoing hemodialysis

CD4(+) T-cell subsets lacking surface CD28 in peripheral blood have been suggested to predispose people to atherosclerosis. To determine if CD4(+)CD28(null) T cells are involved in the immunopathological process of atherosclerotic damage in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD), we characterized peripheral-blood CD4(+)CD28(null) T cells from HD patients and investigated the association between these cells and early atherosclerotic damage. Four color flow cytometric analyses showed that HD patients had significantly higher percentages of CD4(+)CD28(null) T cells in circulating blood than healthy subjects (HS). Most HD patient-derived CD4(+)CD28(null) T cells expressed higher levels of CX3CR1 and produced more intracellular IFN-γ, perforin and granzyme B than their counterparts. Regression analyses demonstrated that the increased levels of CD4(+)CD28(null) T cells were positively correlated to serum levels of C-reactive protein, suggesting systemic inflammation and atherosclerosis. Furthermore, phenotypic and functional studies of CD4(+)CD28(null) T cells showed that these cells were closely correlated with impaired flow-mediated vasodilation and increased intima-media thickness in the carotid artery, which are markers of early atherosclerosis. These data suggested that CD4(+)CD28(null) T cells are important effector cells in HD patients, and that these cells may have a critical role in mediating early atherosclerotic damage.

Plasma protein characteristics of long-term hemodialysis survivors

Hemodialysis (HD) patients are under recurrent circulatory stress, and hemodialysis has a high mortality rate. The characteristics of plasma proteomes in patients surviving long-term HD remain obscure, as well as the potential biomarkers in predicting prognoses. This study reports the proteome analyses of patient plasma from non-diabetic long-term HD (LHD, dialysis vintage 14.9±4.1 years, n = 6) and the age/sex/uremic etiology-comparable short-term HD (SHD, dialysis vintage 5.3±2.9 years, n = 6) using 2-DE and mass spectrometry. In addition, a 4-year longitudinal follow-up of 60 non-diabetic HD patients was subsequently conducted to analyze the baseline plasma proteins by ELISA in predicting prognosis. Compared to the SHD, the LHD survivors had increased plasma vitamin D binding proteins (DBP) and decreased clusterin, apolipoprotein A-IV, haptoglobin, hemopexin, complement factors B and H, and altered isoforms of α1-antitrypsin and fibrinogen gamma. During the 45.7±15 months for follow-up of the 60 HD patient cases, 16 patients died. Kaplan-Meier analysis demonstrated that HD patients with the lowest tertile of the baseline plasma DBP level have a significantly higher mortality rate. Multivariate Cox regression analysis further indicated that DBP is an independent predictor of mortality. In summary, the altered plasma proteins in LHD implicated accelerated atherosclerosis, defective antioxidative activity, increased inflammation/infection, and organ dysfunction. Furthermore, lower baseline plasma DBP in HD patients is related to mortality. The results suggest that the proteomic approach could help discover the potential biomarker in HD prognoses.

Complement profile and activation mechanisms by different LDL apheresis systems

Extracorporeal removal of low-density lipoprotein (LDL) cholesterol by means of selective LDL apheresis is indicated in otherwise uncontrolled familial hypercholesterolemia. During blood-biomaterial interaction other constituents than the LDL particles are affected, including the complement system. We set up an ex vivo model in which human whole blood was passed through an LDL apheresis system with one of three different apheresis columns: whole blood adsorption, plasma adsorption and plasma filtration. The concentrations of complement activation products revealed distinctly different patterns of activation and adsorption by the different systems. Evaluated as the final common terminal complement complex (TCC) the whole blood system was inert, in contrast to the plasma systems, which generated substantial and equal amounts of TCC. Initial classical pathway activation was revealed equally for both plasma systems as increases in the C1rs-C1inh complex and C4d. Alternative pathway activation (Bb) was most pronounced for the plasma adsorption system. Although the anaphylatoxins (C3a and C5a) were equally generated by the two plasma separation systems, they were efficiently adsorbed to the plasma adsorption column before the "outlet", whereas they were left free in the plasma in the filtration system. Consequently, during blood-biomaterial interaction in LDL apheresis the complement system is modulated in different manners depending on the device composition.

Pentoxifylline decreases serum levels of tumor necrosis factor alpha, interleukin 6 and C-reactive protein in hemodialysis patients: results of a randomized double-blind, controlled clinical trial

AIM

The aim of this study was to compare the effect of pentoxifylline versus placebo on serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and C-reactive protein (CRP) of hemodialysis (HD) patients.

METHODS

This is a randomized double-blind, controlled clinical trial. HD patients without infection or drugs with anti-inflammatory effect were randomly allocated to a study (n = 18, pentoxifylline 400 mg/day) or control (n = 18, placebo) group; all patients had arteriovenous fistula. Besides clinical and laboratory monthly assessments, serum TNF-α and IL-6 (ELISA) and CRP (nephelometry) were measured at 0, 2 and 4 months.

RESULTS

All the inflammation markers significantly (P < 0.05) decreased in the pentoxifylline group: TNF-α [baseline 0.4 (0-2) versus final 0 (0-0) pg/mL], IL-6 [baseline 9.4 (5-14) versus final 2.9 (2-5) pg/mL] and CRP [baseline 7.1 (3-20) versus final 2.6 (1-8) mg/L], whereas no significant changes were observed in the placebo group: TNF-α [baseline 0 (0-0) versus final 1.2 (0-4) pg/mL], IL-6 [baseline 8.0 (5-11) versus final 8.7 (4-11) pg/mL] and CRP [baseline 4.5 (2-9) versus final 3.8 (3-23) mg/L].

CONCLUSIONS

Pentoxifylline significantly decreased serum concentrations of TNF-α, IL-6 and CRP compared to placebo. Pentoxifylline could be a promising and useful strategy to reduce the systemic inflammation frequently observed in patients on HD.

Combined angiotensin-converting enzyme inhibition and receptor blockade associate with increased risk of cardiovascular death in hemodialysis patients

To compare the relative effectiveness of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in reducing cardiovascular mortality in chronic hemodialysis patients, we conducted an observational analysis of all patients initiated on ACEI or ARB therapy undergoing chronic hemodialysis at a large dialysis provider. Survival curves with mortality hazard ratios (HRs) were generated using the Kaplan-Meier method and Cox regression. Outcomes were compared using inverse probability of treatment weighting and propensity score matching. Over 6 years, 22,800 patients were newly initiated on an ACEI and 5828 on an ARB after at least 60 days of chronic hemodialysis. After adjustment for baseline cardiovascular risk factors, there was no significant difference in the risk of cardiovascular, all-cause, or cerebrovascular mortality in patients initiated on an ARB compared with an ACEI (HR of 0.96). A third of 28,628 patients, newly started on an ACEI or ARB, went on to another antihypertensive medication in succession. After adjustment for risk factors, 701 patients initiated on combined ACEI and ARB therapy (HR of 1.45) or 6866 patients on ACEI and non-ARB antihypertensive agent (HR of 1.27) were at increased risk of cardiovascular death compared with 1758 patients initiated on an ARB and non-ACEI antihypertensive therapy. Thus, an ARB, in combination with another antihypertensive medication (but not an ACEI), may have a beneficial effect on cardiovascular mortality. As observational studies may be confounded by indication, even when adjusted, randomized clinical trials are needed to confirm these findings.

The impact of beta2-microglobulin clearance on the risk factors of cardiovascular disease in hemodialysis patients

beta2-Microglobulin (beta2M) is an independent predictor of outcome for hemodialysis (HD) patients and a representative substance of middle molecules. We tested the relationship among serum beta2M levels and cardiovascular disease (CVD) risk factors in HD patients. A total of 132 HD patients were divided according to the dialysis membrane used [property; cellulose and synthetic or beta2M clearance; low filtration (LF), middle filtration (MF), and high filtration (HF)]. There was no significant difference in CVD risk factors between cellulose and synthetic groups. On the other hand, serum beta2M, highly-sensitive C-reactive protein (hCRP), troponin-T (TnT), and myeloperoxidase (MPO) levels of LF were significantly higher and those of prealbumin (PA) were lower than the MF and HF. Serum beta2M level was positively correlated with hCRP, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), MPO, TnT, N-terminal pro-B-type natriuretic peptide (NT-proBNP) and inversely correlated with PA and ankle-brachial index (ABI). There was a significant correlation between serum beta2M levels and various CVD risk factors in HD. Cardiovascular disease risk factors in HD patients were dependent on the beta2M clearance but not membrane property.

Toll-like receptor expression in monocytes in patients with chronic kidney disease and haemodialysis: relation with inflammation

BACKGROUND

Inflammation is one of the main contributors to atherosclerosis in haemodialysis (HD) patients. Activation of Toll-like receptors (TLRs) leads to inflammatory response. In this study, we aimed to evaluate the expression of TLRs on monocytes and relate their expression with inflammation in chronic kidney disease (CKD) and HD patients.

METHODS

Thirty-four age- and gender-matched controls and stage 3-4 CKD patients and thirty-two HD patients were included in each study group. The effect of HD on the expression of Toll-like receptor-2 (TLR-2) and Toll-like receptor-4 (TLR-4) on CD14( +) monocytes was determined at the beginning (baseline), during (120 min) and following (300 min and 24 h) HD and compared with control and stage 3-4 CKD groups. The HD procedure was performed by using low-flux polysulphone dialysers. In addition, serum IL-6 levels were evaluated in both groups at baseline and after a HD session.

RESULTS

The percentage of CD14( +) monocytes expressing TLR-2 were similar in all of the study groups, whereas the percentage of CD14( +) monocytes expressing TLR-4 were significantly lower in both stage 3-4 CKD and HD patients at baseline than in controls. The mean fluorescence intensities (MFI) of TLR-2 were significantly lower in controls than in stage 3-4 CKD and HD patients at baseline. The MFI of TLR-4 was similar in all of the groups. The percentage of CD14( +) monocytes expressing TLR-2 did not change during and after HD. The MFI of TLR-2 decreased at 120 min of HD compared with baseline (1837 ± 672 vs 1650 ± 578, P < 0.05), and recovered back to baseline values at 300 min and at 24 h post-HD. MFI of TLR-4 increased at 24 h compared with baseline (941 ± 294 vs 1087 ± 441, P < 0.05). Serum IL-6 levels correlated with MFI of TLR-2 and TLR-4 in stage 3-4 CKD patients and in HD patients at baseline and after HD in univariate analysis. Stepwise multiple regression analysis revealed that MFI of TLR-2 was an independent determinant of serum IL-6 concentrations in stage 3-4 CKD and in HD patients at baseline, at 300 min and at 24 h post-HD. Conclusions. Our study demonstrates that TLR-2 is associated with the inflammatory response of non-dialysed and dialysed CKD patients.

Neutrophil gelatinase-associated lipocalin levels in chronic haemodialysis patients

Neutrophil gelatinase-associated lipocalin (NGAL), a small 25 kDa protein strongly induced in injured renal tubular cells, represents an interesting emerging biomarker in the field of clinical nephrology. The aim of the present pilot study was to analyze circulating NGAL levels in a small cohort of 30 patients on chronic haemodialysis (HD), in order to assess any relationships with different laboratory and clinical parameters. Pre- and post-HD levels were higher in patients than in healthy subjects (485.2 +/- 49.7 vs 51.2 +/- 4.6 ng/mL; P < 0.001; and 167.4 +/- 48.0 vs 51.2 +/- 4.6 ng/mL; P = 0.01). Furthermore, a single HD session decreased NGAL levels by approximately fourfold (485.2 +/- 49.7 vs 167.4 +/- 48.0 ng/mL; p:0.01), with a reduction ratio of 73 +/- 14%. At baseline, direct and independent correlations were found between NGAL and, respectively, high-sensitivity C-reactive protein (beta = 0.34; P = 0.03) and spKt/V (beta = 0.35; P = 0.02). The findings showed that HD patients have chronically increased levels of circulating NGAL. However, with a single HD session, a marked reduction was achieved in circulating NGAL values, probably as a result of an important dialytic removal, similar to that observed for other cytokines. Finally, the direct independent correlation found between NGAL and spKt/V raises the question of whether, in the future, NGAL may also become a useful tool in predicting the adequacy of dialysis and in guiding the management of dialysis prescriptions.

[Evaluation of extracorporeal liver support systems in the treatment of liver failure. A systematic review]

OBJECTIVE

To evaluate the safety and efficacy of the MARS and Prometheus extracorporeal liver support systems in the treatment of liver failure.

DESIGN

We performed a systematic review of the literature from January 1999 to June 2009 in the Medline, Embase, HTA, DARE, NHSEED, Cochrane Library Plus, Clinical Trials Registry and HSRPROJ databases. Study selection was based on a series of previously established inclusion criteria related to the study design, population, type of intervention, language, and outcome measures.

PATIENTS AND INTERVENTIONS

Patients with acute liver failure or acute exacerbations of chronic liver failure treated with the MARS or Prometheus systems.

OUTCOME MEASURES

Data on safety, long-term survival, clinical effects and biochemical and hemodynamic variables.

RESULTS

We selected 22 studies evaluating the safety and efficacy of the MARS and Prometheus systems. Adequate evaluation of these techniques was hampered by the heterogeneity of the studies and their methodological limitations.

CONCLUSIONS

Extracorporeal liver support systems are able to purify both hydrosoluble and protein-bound substances. However, current data show that only the MARS system reduces mortality in acute liver failure and in acute exacerbations of chronic liver failure, although this reduction is non-significant. These techniques can be considered safe, with adverse effects similar to those of the control group. Their main indication is severe liver failure, for short periods while the liver recovers or a liver transplant becomes available.

Is systemic inflammation of hemodialysis patients improved with the use of enalapril? Results of a randomized, double-blinded, placebo-controlled clinical trial

This study compared the effect of enalapril versus placebo on serum tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C-reactive protein (CRP) in hemodialysis in a randomized, double- blinded, controlled clinical trial. Patients without infection or antiinflammatory drugs were randomly allocated to a study (n = 13, enalapril, 20 mg/day) or control (n = 12, placebo) group; all had arteriovenous fistula. Serum TNF-alpha, IL-6, and CRP were measured at 0, 1, and 3 months. Systolic blood pressure (baseline vs. final) was 151 +/- 25 vs. 135 +/- 19 mm Hg (p < 0.05) in the study group and 154 +/- 21 vs. 144 +/- 27 mm Hg in control group; diastolic blood pressure was 86 +/- 9 vs. 76 +/- 13 and 91 +/- 16 vs. 81 +/- 18 mm Hg, respectively; median (percentiles 25%-75%) IL-6 (baseline vs. final) was 4.2 (3-8) vs. 4.1 (2-9) pg/mL and 6.3 (3-9) vs. 6.7 (3-8) pg/mL; and CRP was 1.9 (1-7) vs. 3.0 (1-12) mg/L and 4.7 (1-16) vs. 3.9 (2-16) mg/L, respectively. TNF-alpha was detected in only two patients. Enalapril significantly reduced blood pressure in hemodialysis patients, but it did not decrease IL-6 and CRP compared with placebo.

Effect of hemodialysis before transplant surgery on renal allograft function--a pair of randomized controlled trials

BACKGROUND

Hemodialysis immediately before kidney transplant surgery has been suggested to adversely affect early graft function. On the other hand, considering its profound antiinflammatory effects, a beneficial impact of regional citrate anticoagulation on the evolution of graft function can be speculated. We sought to assess the clinical impact of preoperative hemodialysis and dialysis anticoagulation in two related randomized trials.

METHODS

Eligible kidney transplant candidates with a serum potassium less than or equal to 5.0 mEq/L were randomized to receive dialysis or no dialysis before deceased donor transplantation. Patients with a potassium more than 5.0 mEq/L were randomized to receive dialysis with heparin or citrate anticoagulation. The primary endpoint was the estimated glomerular filtration rate (eGFR) at posttransplant day 5.

RESULTS

The first comparison (56 vs. 54 patients) revealed no effect of dialysis on eGFR at day 5 (primary endpoint, 12 [interquartile range 5-36] vs. 13 [5-37] mL/min/1.73 m2, P=0.98), rates of delayed graft function (22% vs. 27%, P=0.66), cellular rejection (20% vs. 24%, P=0.65), and C4d-positive dysfunction (2% vs. 9%, P=0.11) or 1-year death-censored graft survival (89% vs. 91%, P=0.51). Comparing citrate with heparin anticoagulation (44 vs. 66 patients), no differences in eGFR at day 5 (17 [8-31] vs. 14 [6-38] ml/min/1.73 m2, P=0.57), delayed graft function (21% vs. 30%, P=0.28), cellular rejection (23% vs. 33%, P=0.29), and graft survival (90% vs. 88%, P=0.44) were found. For citrate anticoagulation, less C4d-positive rejection episodes (P=0.08) and higher 1-year eGFR levels (P=0.03) were observed.

CONCLUSION

Pretransplant hemodialysis and anticoagulation may not affect early graft function in a meaningful way.

Cytokine patterns and survival in haemodialysis patients

BACKGROUND

Increased pro-inflammatory cytokine levels are associated with decreased survival. We performed factor analyses to determine if pro-inflammatory and anti-inflammatory cytokines in haemodialysis (HD) patients load onto one or two discrete factors and assessed if patients with a specific pattern of high pro-inflammatory cytokines have decreased survival compared to patients with a high anti-inflammatory cytokine pattern.

METHODS

We evaluated 231 HD patients and analyzed them based on the three most common cytokine distribution patterns seen: a high pro-inflammatory group, a high anti-inflammatory group and all others. Survival and Cox regression analyses were performed.

RESULTS

Factor analyses of individual cytokines showed that they loaded onto a single factor. Sixty-five patients had a pro-inflammatory pattern of high IL-1, IL-6 and TNF-alpha levels and low anti-inflammatory parameters, including IL-2, IL-4, IL-5, IL-12, CH50 and T-cell number. The next most frequent cytokine pattern was found in 20 patients with high levels of anti-inflammatory parameters. The patients with high pro-inflammatory cytokines had decreased survival compared to patients without a characteristic cytokine pattern.

CONCLUSIONS

Further research is needed to better define the underlying causes of increased inflammation among end-stage renal disease patients and to apply anti-inflammatory therapies that may mitigate adverse effects on patient outcomes.

Inflammation in chronic kidney disease: role in the progression of renal and cardiovascular disease

Inflammation is the response of the vasculature or tissues to various stimuli. An acute and chronic pro-inflammatory state exists in patients with chronic kidney disease (CKD), contributing substantially to morbidity and mortality. There are many mediators of inflammation in adults with CKD and end-stage kidney disease (ESKD), including hypoalbuminemia/malnutrition, atherosclerosis, advanced oxidation protein products, the peroxisome proliferators-activated receptor, leptin, the thiobarbituric acid reactive system, asymmetric dimethyl arginine, iron, fetuin-A, and cytokines. Inflammation contributes to the progression of CKD by inducing the release of cytokines and the increased production and activity of adhesion molecules, which together contribute to T cell adhesion and migration into the interstitium, subsequently attracting pro-fibrotic factors. Inflammation in CKD also causes mortality from cardiovascular disease by contributing to the development of vascular calcifications and endothelial dysfunction. Similar to the situation in adults, cardiovascular disease in pediatric CKD is linked to inflammation: abnormal left ventricular wall geometry is positively associated with markers of inflammation. This review focuses on traditional and novel mediators of inflammation in CKD and ESKD, and the deleterious effect inflammation has on the progression of renal and cardiovascular disease.

Specific adsorption of some complement activation proteins to polysulfone dialysis membranes during hemodialysis

Dialyser bioincompatibility is an important factor contributing to complications of hemodialysis with well known systemic consequences. Here we studied the local processes that occur on dialysis membranes by eluting proteins adsorbed to the polysulfone dialyser membranes of 5 patients after 3 consecutive routine maintenance hemodialysis sessions. At the end of each procedure, a plasma sample was also collected. These eluates and their accompanying plasma samples were separated by 2-dimensional gel electrophoresis; all proteins that were present in all patients were analyzed by tandem mass spectrometry; and a ratio of the relative spot intensity of the eluate to plasma was calculated. Of 153 proteins detected, 84 were found in all patients, 57 of which were successfully identified by mass spectrometry as 38 components of 23 unique proteins. In 10 spots the relative eluate intensity differed significantly from that in the plasma, implying preferential adsorption. These proteins included ficolin-2, clusterin, complement C3c fragment, and apolipoprotein A1. Our finding of a selective binding of ficolin-2 to polysulfone membranes suggests a possible role of the lectin complement pathway in blood-dialyser interactions.