Albumin handling in different hemodialysis modalities

Malnutrition as a potential predictor of mortality in chronic kidney disease patients on dialysis: A systematic review and meta-analysis

BACKGROUND & AIMS

Malnutrition, a significant problem in patients with chronic kidney disease (CKD), is linked to lower health-related quality of life, longer and more frequent hospital admissions, worse functional capacity, and higher levels of morbidity. However, the extent of its impact on mortality is poorly elucidated. This systematic review and meta-analysis aimed to investigate the impact of malnutrition on mortality among CKD patients on dialysis.

METHODS

This meta-analysis was designed and performed in accordance with the PRISMA guidelines (CRD42023394584). A systematic electronic literature search was conducted in PubMed, ScienceDirect, and Embase to identify relevant cohort studies. The studies that reported nutritional status and its impact on mortality in patients were considered for analysis. The generic inverse variance method was used to pool the hazard ratio effect estimates by employing a random effects model. The Newcastle-Ottawa scale was used for the quality assessment. The statistical analysis was performed by utilizing RevMan and CMA 2.0.

RESULTS

A total of 29 studies that comprised 11,063 patients on dialysis whose nutritional status was evaluated were eligible for quantitative analysis. Based on a comparison between the "malnutrition" category and the reference "normal nutrition status" category, the results showed that the overall pooled hazard risk (HR) for mortality was (HR 1.49, 95% CI: 1.36-1.64, p < 0.0001). According to the subgroup analysis, the hemodialysis subgroup had greater mortality hazards (HR 1.53; 95% CI 1.38-1.70, p < 0.0001), compared to the peritoneal dialysis subgroup (HR 1.26; 95% CI 1.15-1.37, p < 0.00001). Additionally, the overall incidence of mortality was explored but the authors were unable to combine the results due to limitations with the data.

CONCLUSION

The findings conclude that malnutrition is a strong predictor of mortality among patients on dialysis, with the hemodialysis subgroup having a higher mortality hazard compared to the peritoneal dialysis subgroup. The results of this study will advocate for early nutritional evaluation and timely dietary interventions to halt the progression of CKD and death.

On the total albumin losses during haemocatharsis

Excessive albumin losses during HC (haemocatharsis) are considered a potential cause of hypoalbuminemia-a key risk factor for mortality. This review on total albumin losses considers albumin "leaking" into the dialysate and losses due to protein/membrane interactions (i.e. adsorption, "secondary membrane formation" and denaturation). The former are fairly easy to determine, usually varying at the level of ~ 2 g to ~ 7 g albumin loss per session. Such values, commonly accepted as representative of the total albumin losses, are often quoted as limits/standards of permissible albumin loss per session. On albumin mass lost due to adsorption/deposition, which is the result of complicated interactions and rather difficult to determine, scant in vivo data exist and there is great uncertainty and confusion regarding their magnitude; this is possibly responsible for neglecting their contribution to the total losses at present. Yet, many relevant in vitro studies suggest that losses of albumin due to protein/membrane interactions are likely comparable to (or even greater than) those due to leaking, particularly in the currently favoured high-convection HDF (haemodiafiltration) treatment. Therefore, it is emphasised that top research priority should be given to resolve these issues, primarily by developing appropriate/facile in vivo test-methods and related analytical techniques.

Feasibility of hemoperfusion using extracorporeal therapy in the horse

Objective

Develop, implement, and monitor for adverse effects of, a novel hemoperfusion therapy in adult horses.

Methods

A prospective, observational feasibility study using three healthy adult horses from the North Carolina State University teaching herd. Health status was determined by physical exam, complete blood count, coagulation panel, and serum biochemistry. Each horse was instrumented with a 14 Fr × 25 cm double-lumen temporary hemodialysis catheter and underwent a 240 min polymer-based hemoperfusion session. Horses were administered unfractionated heparin to maintain anti-coagulation during the session. Given the novelty of this therapy in horses, each horse was treated as a learning opportunity that informed an iterative process of protocol development and modification.

Measurements and main results

Our long-term goal is to investigate potential clinical applications of hemoperfusion in horses, including cytokine reduction in horses with severe SIRS/sepsis. Horses were monitored for changes in clinical exam, biochemistry and hematology parameters. Additionally, cytokines were quantified to determine whether extracorporeal hemadsorption therapy alone caused an inflammatory response. Our results show that hemoperfusion therapy was associated with decreased platelet counts and serum albumin concentration. There was no significant change in plasma cytokine concentrations with hemoperfusion therapy. In one horse, the cytokine concentrations decreased, as previously reported with hemoperfusion therapy in humans.

Hypothesis

We hypothesized that hemoperfusion therapy could be performed in healthy adult horses without significant adverse effects.

Conclusion

Polymer-based hemoperfusion is a feasible extracorporeal therapy (ECT) modality for adult horses. Additional studies are needed to further establish clinical protocols, as well as establish efficacy of polymer-based hemoperfusion for treatment of various conditions in horses, including intoxications, immune-mediated conditions, and sepsis.

Advances in uremic toxin detection and monitoring in the management of chronic kidney disease progression to end-stage renal disease

Patients with end-stage kidney disease (ESKD) rely on dialysis to remove toxins and stay alive. However, hemodialysis alone is insufficient to completely remove all/major uremic toxins, resulting in the accumulation of specific toxins over time. The complexity of uremic toxins and their varying clearance rates across different dialysis modalities poses significant challenges, and innovative approaches such as microfluidics, biomarker discovery, and point-of-care testing are being investigated. This review explores recent advances in the qualitative and quantitative analysis of uremic toxins and highlights the use of innovative methods, particularly label-mediated and label-free surface-enhanced Raman spectroscopy, primarily for qualitative detection. The ability to analyze uremic toxins can optimize hemodialysis settings for more efficient toxin removal. Integration of multiple omics disciplines will also help identify biomarkers and understand the pathogenesis of ESKD, provide deeper understanding of uremic toxin profiling, and offer insights for improving hemodialysis programs. This review also highlights the importance of early detection and improved understanding of chronic kidney disease to improve patient outcomes.

Current dialyzer classification in Japan and mortality risk in patients undergoing hemodialysis

Dialyzers are classified into five types based on their β2-microglobulin clearance rate and albumin sieving coefficient: Ia, Ib, IIa, and IIb. In addition, a new classification system introduced a type S dialyzer. However, limited information is available regarding the impact of dialyzer type on patient outcomes. A cohort study was conducted using data from the Japanese Society for Dialysis Therapy Renal Data Registry database. Total 181,804 patients on hemodialysis (HD) were included in the study, categorized into four groups (type Ia, IIa, IIb, and S). The associations between each group and two-year all-cause mortality were assessed using Cox proportional hazard models. Furthermore, propensity score-matching analysis was performed. By the end of 2019, 34,185 patients on dialysis had died. After adjusting for all confounders, the risk for all-cause mortality was significantly lower in the type IIa, and S groups than in the type Ia group. These significant findings were consistent after propensity score matching. In conclusion, our findings suggest that super high-flux dialyzers, with a β2-microglobulin clearance of ≥ 70 mL/min, may be beneficial for patients on HD, regardless of their albumin sieving coefficient. In addition, type S dialyzers may be beneficial for elderly and malnourished patients on dialysis.Trial registration number: UMIN000018641.

Correlation of Serum Albumin Levels With Laboratory Parameters in Automated Peritoneal Dialysis and Continuous Ambulatory Peritoneal Dialysis Patients: A Prospective Cohort Study

Background Peritoneal dialysis (PD) is a treatment option for end-stage renal disease (ESRD) patients, with automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) being the two main modalities. APD has reported benefits such as reduced peritonitis rates, improved ultrafiltration, and enhanced quality of life. However, some studies have found potential negative consequences of APD, and the impact on survival outcomes is limited and contradictory. Selecting the appropriate PD modality for ESRD patients should be individualized based on various factors, including nutritional status, demographic factors, laboratory findings, and other outcomes. PD patients are at high risk of malnutrition, and serum albumin is commonly used as a marker of nutritional status. Continuous monitoring of laboratory values may be beneficial for identifying nutritional deficiencies in a timely manner. Methodology This prospective cohort study aimed to compare APD and CAPD modalities in relation to serum albumin levels, demographic factors, and other laboratory parameters. The sample consisted of patients with ESRD treated with PD, who were divided into two groups per baseline albumin level. The study collected data on demographic, clinical, and laboratory characteristics, as well as comorbidities. The data were analyzed using SPSS version 26 (IBM Corp., Armonk, NY, USA), and statistical tests, such as the chi-square test and repeated-measures analysis of variance (ANOVA), were conducted to determine significant associations and differences between variables. Results The study included a total of 85 patients with ESRD who required PD as a treatment modality. Among them, 71 patients were undergoing APD, and 14 patients were undergoing CAPD. The study found that there were no significant differences in demographic factors, laboratory parameters, or medical history parameters between APD and CAPD patients with different albumin levels. The patients were followed up for six months and laboratory parameters were evaluated. Repeated-measures ANOVA showed that there were no significant variations in both APD and CAPD patients. However, Spearman's rank correlation test revealed statistically important correlations between albumin and some laboratory parameters in both APD and CAPD patients at different assessment stages, including hemoglobin, sodium, transferrin, uric acid, phosphate, total protein, cholesterol, and triglycerides (p < 0.05). Conclusions Serum albumin levels appeared to be unaffected by the choice of PD modality. There were significant correlations between serum albumin levels and specific laboratory findings, including total protein, across all assessment stages for both APD and CAPD patients. These findings underscore the importance of continuous laboratory monitoring for PD patients.

Albumin redox state of maintenance haemodialysis patients is positively altered after treatment

BACKGROUND AND AIM

Maintenance haemodialysis patients have increased morbidity and mortality which is mainly driven by an elevated inflammation level due to the uraemic milieu. A major part of this increased inflammation level is the degree of oxidative stress which can be assessed by albumin redox state (ARS). Aim of this study was to evaluate how the ARS is affected by a haemodialysis treatment and different dialyzer properties.

METHODS

ARS was determined before and after haemodialysis treatment by fractionating it into reduced human mercaptalbumin (HMA), reversibly oxidized human non-mercaptalbumin 1 (HNA-1), and irreversibly oxidized human non-mercaptalbumin 2 (HNA-2) by high-performance liquid chromatography. In healthy individuals, albumin circulates in the following proportions: HMA 70-80%, HNA-1 20-30% and HNA-2 2-5%. High flux (FX 100 [Fresenius Medical Care], BG 1.8 [Toray], Xevonta Hi 18 [B. Braun], CTA-2000 [Kawasumi]) and low flux FX10 [Fresenius Medical Care] dialyzers were used.

RESULTS

58 patients (59% male, median age 68 years, median time on haemodialysis 32 month) were included in the study. Before haemodialysis treatment, HMA (median 55.9%, IQR 50.1-61.2%) was substantially lower than in healthy individuals. Accordingly, oxidized albumin fractions were above the level of healthy individuals (median HNA-1 38.5%, IQR 33.3-43.2%; median HNA-2 5.8%, IQR 5.1-6.7%). Before haemodialysis treatment HMA was significantly higher in patients usually treated with high flux membranes (p < 0.01). After haemodialysis treatment there was a significant increase of HMA and a decrease of HNA-1 and HNA-2 (p < 0.01). These effects were more pronounced in patients treated with high flux dialyzers (p < 0.01). There were no differences of ARS alteration with regard to the dialyzer´s sterilization mode or the presence of diabetes.

CONCLUSION

The study confirms that the ARS is positively altered by haemodialysis and shows for the first time that this effect depends on dialyzer properties.

Liver replacement therapy with extracorporeal blood purification techniques current knowledge and future directions

Clinically, it is highly challenging to promote recovery in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). Despite recent advances in understanding the underlying mechanisms of ALF and ACLF, standard medical therapy remains the primary therapeutic approach. Liver transplantation (LT) is considered the last option, and in several cases, it is the only intervention that can be lifesaving. Unfortunately, this intervention is limited by organ donation shortage or exclusion criteria such that not all patients in need can receive a transplant. Another option is to restore impaired liver function with artificial extracorporeal blood purification systems. The first such systems were developed at the end of the 20^th century, providing solutions as bridging therapy, either for liver recovery or LT. They enhance the elimination of metabolites and substances that accumulate due to compromised liver function. In addition, they aid in clearance of molecules released during acute liver decompensation, which can initiate an excessive inflammatory response in these patients causing hepatic encephalopathy, multiple-organ failure, and other complications of liver failure. As compared to renal replacement therapies, we have been unsuccessful in using artificial extracorporeal blood purification systems to completely replace liver function despite the outstanding technological evolution of these systems. Extracting middle to high-molecular-weight and hydrophobic/protein-bound molecules remains extremely challenging. The majority of the currently available systems include a combination of methods that cleanse different ranges and types of molecules and toxins. Furthermore, conventional methods such as plasma exchange are being re-evaluated, and novel adsorption filters are increasingly being used for liver indications. These strategies are very promising for the treatment of liver failure. Nevertheless, the best method, system, or device has not been developed yet, and its probability of getting developed in the near future is also low. Furthermore, little is known about the effects of liver support systems on the overall and transplant-free survival of these patients, and further investigation using randomized controlled trials and meta-analyses is needed. This review presents the most popular extracorporeal blood purification techniques for liver replacement therapy. It focuses on general principles of their function, and on evidence regarding their effectiveness in detoxification and in supporting patients with ALF and ACLF. In addition, we have outlined the basic advantages and disadvantages of each system.

Systematic review to compare the outcomes associated with the modalities of expanded hemodialysis (HDx) versus high-flux hemodialysis and/or hemodiafiltration (HDF) in patients with end-stage kidney disease (ESKD)

BACKGROUND

This systematic review was performed to identify recent published comparative evidence on the efficacy, effectiveness, and safety of expanded hemodialysis (HDx) versus high-flux HD and/or hemodiafiltration (HDF) for long-term outcomes in end-stage kidney disease.

METHODS

Systematic literature review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Medline, Medline® Epub Ahead of Print, EconLit, Embase, and EBM reviews were searched to identify relevant publications from 2013 onwards. Eligibility criteria included clinical studies reporting mortality, hospitalizations, cardiovascular outcomes, economic evaluations, cost studies, and quality of life (QoL) studies.

RESULTS

A total of 79 relevant studies were identified with 29 prioritized for detailed analysis; four compared HDx to HD, one compared HDF and HDx, and 24 compared HDF with HD. A total of 13 randomized controlled trial (RCT)-based studies were identified; 11 compared HDF with HD, one compared HDx with HD, and one compared HDF with HDx. Follow-up duration ranged from 16 weeks to 7 years for HDF studies and from 12 weeks to 1 year for HDx studies. HDF showed significant improvements in mortality, cardiovascular outcomes, hospitalizations, and QoL versus high-flux HD. One study reported mortality outcomes for HDx and found no difference versus HDF. QoL benefits with HDx were reported in a small number of studies.

CONCLUSION

The efficacy and safety of HDF is supported by a robust evidence base that includes several RCTs. While HDx may offer benefits over high-flux HD, long-term studies are required to compare HDx with online high volume HDF.

REGISTRATION

PROSPERO registration number: CRD42022301009.

A Causal-Pathway Phenotype of Chronic Fatigue Syndrome due to Hemodialysis in Patients with End-Stage Renal Disease

BACKGROUND

End-stage renal disease (ESRD) is associated with fatigue and physiosomatic symptoms.

OBJECTIVE

The objective of this study is to delineate the associations between severity of fatigue and physio-somatic symptoms and glomerular filtration rate, inflammatory biomarkers, and Wnt/cateninpathway proteins.

METHODS

The Wnt-pathway related proteins β-catenin, Dickkopf-related protein 1 (DKK1), R-spondin- 1, and sclerostin were measured by ELISA technique in 60 ESRD patients and 30 controls. The Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale was used to assess the severity of FF symptoms.

RESULTS

ESRD is characterized by a significant increase in the total FF score, muscle tension, fatigue, sadness, sleep disorders, gastro-intestinal (GI) symptoms, and a flu-like malaise. The total-FF score was significantly correlated with serum levels of urea, creatinine, and copper (positively), and β-catenin, eGFR, hemoglobin, albumin, and zinc (inversely). The total-FF score was associated with the number of total dialysis and weekly dialysis sessions, and these dialysis characteristics were more important in predicting FF scores than eGFR measurements. Partial Least Squares analysis showed that the FF score comprised two factors that are differently associated with biomarkers: a) 43.0% of the variance in fatigue, GI symptoms, muscle tension, sadness, and insomnia is explained by hemoglobin, albumin, zinc, β-catenin, and R-spondin-1; and b) 22.3% of the variance in irritability, concentration and memory impairments by increased copper and cations/chloride ratio, and male sex.

CONCLUSION

ESRD patients show high levels of fatigue and physio-somatic symptoms associated with hemodialysis and mediated by dialysis-induced changes in inflammatory pathways, the Wnt/catenin pathway, and copper.

Assessment of the Influence of Asymmetric Triacetate Cellulose Membrane on the Rate of Removal of Middle Molecular Weight Uremic Toxins in Patients Treated with Postdilution Online Hemodiafiltration

BACKGROUND: Postdilution online hemodiafiltration (OL-HDF) effectively removes uremic toxins of middle molecular weight from the blood of patients with end-stage chronic kidney disease. The rate of removal of uremic toxins depends on the type of dialysis membrane, blood flow rate (Qb), net ultrafiltration flow rate (Qnuf), and total convective volume (Vconv). AIM: The aim of this study was to examine the efficacy of asymmetric triacetate cellulose dialysis membrane in patients on post-dilution OL-HDF. METHODS: Thirty-five patients treated with post-dilution OL-HDF hemodiafiltration for at least 3 months were examined. The main parameters for assessing the efficiency of removal of uremic toxins of middle molecular weight are the concentration of β2-microglobulin (β2-M) and interleukin-6 (IL-6) in serum before and after a single session of post-dilution OL-HDF. The followings were used for statistical analysis: Kolmogorov–Smirnov test, Student’s T test for bound samples and Wilcoxon test. RESULTS: The average Vconv was 20.90 ± 3.30 liters/session. The β2-M reduction index during a single session of postdilution OL-HDF was 71.10 ± 6.39%, the IL-6 reduction index was 43.75 ± 15.60%, and the albumin reduction index was 4.55 ± 2.31%. CONCLUSION: The asymmetric triacetate cellulose dialysis membrane effectively removes β2-M and IL-6 during a single session of postdilution OL-HDF. The β2-M reduction index is ∼70%, the IL-6 reduction index is ∼40%, and albumin loss is <4.0 g/4 h. The examined dialysis membrane and dialysis modality prevent the development of amyloidosis associated with dialysis, microinflammation and reduce the risk of developing atherosclerotic cardiovascular diseases in the population of patients treated with regular hemodiafiltration.

The change in Geriatric Nutritional Risk Index is associated with mortality in patients who start hemodialysis: Korean Renal Data Registry, 2016-2018

Malnutrition is common in patients undergoing hemodialysis (HD) and is associated with mortality. This study aimed to investigate the association between changes in nutrition status measured by the Geriatric Nutritional Risk Index (GNRI) and all-cause mortality in patients who started HD. A nationwide retrospective cohort study was conducted based on the Korean Renal Data System database. Patients who started HD from January 2016 to December 2018, and were eligible for GNRI and GNRI trend were included. GNRI trend was a longitudinal change of GNRI, assessed by random slope in a mixed-effect model. Positive and negative random slopes in each patient were assigned to positive and negative GNRI trends. A total of 2313 patients were included and median follow-up period was 3.1 (2.6-3.7) years. GNRI values decreased over time (estimate - 1.212, 95% confidence interval (CI) - 1.116-0.692) and positive GNRI trend was associated with survival benefit (hazard ratio 0.55, 95% CI 0.36-0.84) after multivariate adjustment. These findings show that serial GNRI assessment, besides GNRI, is a useful prognostic factor for mortality in patients who start HD.

Effects of high albumin leakage on survival between online hemodiafiltration and super high-flux hemodialysis: the HISTORY study

Background

All-cause mortality is lower with a high substitution volume in predilution (pre) and postdilution (post) online hemodiafiltration (OHDF) than with hemodialysis (HD), and mortality does not significantly differ between pre- and post-OHDF groups. Despite the improved survival with a high substitution volume, there may be limitations. On the other hand, either normoalbuminemia or high albumin leakage in HD can reduce mortality, and super high-flux (SHF) membrane dialyzers can reduce mortality compared with low-flux and high-flux membrane dialyzers. Here, we investigated the associations of serum albumin concentration (s-Alb), albumin leakage, and substitution volume with all-cause mortality in OHDF and SHF-HD.

Methods

In a 3-year retrospective observational study of patients receiving dialysis from April 1 to July 1, 2017, we developed a propensity score-matched model using 783 stable patients (SHF-HD, 355; OHDF, 428). We used the log-rank test to compare Kaplan–Meier survival curves and Cox regression analysis to calculate hazard ratio (HR). Cox regression analysis was also used to compare the effect of estimated albumin leakage (EAL) and substitution volume on 3-year all-cause mortality.

Results

All-cause mortality was significantly lower with high EAL than with low EAL (SHF-HD: P = 0.012, log-rank test; HR, 0.44; 95% confidence interval [CI] 0.23–0.85; OHDF: P = 0.027, log-rank test; HR, 0.41; 95% CI 0.18–0.93). The mortality of high EAL was not significantly different between high and low s-Alb in SHF-HD (3.5 ± 0.1 and 3.2 ± 0.2 g/dL) and OHDF (3.6 ± 0.2 and 3.2 ± 0.1 g/dL), despite significant differences in s-Alb. Mortality did not significantly differ between SHF-HD and OHDF with higher EAL ranges or a lower difference in EAL. Mortality in pre-OHDF was significantly correlated with EAL (P = 0.007, beta − 0.32) rather than substitution volume, and mortality in post-OHDF was not analyzed because of fewer deaths.

Conclusions

The results suggest that survival is improved more with high EAL than with low EAL in both OHDF and SHF-HD patients, that high EAL with mild-to-moderate hypoalbuminemia does not necessarily worsen survival in OHDF and SHF-HD patients, and that survival is equivalent between OHDF and SHF-HD patients with a similar level of EAL.

Recent advances of gut microbiota in chronic kidney disease patients

Chronic kidney disease (CKD) is a worldwide public health issue and has ultimately progressed to an end-stage renal disease that requires life-long dialysis or renal transplantation. However, the underlying molecular mechanism of these pathological development and progression remains to be fully understood. The human gut microbiota is made up of approximately 100 trillion microbial cells including anaerobic and aerobic species. In recent years, more and more evidence has indicated a clear association between dysbiosis of gut microbiota and CKD including immunoglobulin A (IgA) nephropathy, diabetic kidney disease, membranous nephropathy, chronic renal failure and end-stage renal disease. The current review describes gut microbial dysbiosis and metabolites in patients with CKD thus helping to understand human disease. Treatment with prebiotics, probiotics and natural products can attenuate CKD through improving dysbiosis of gut microbiota, indicating a novel intervention strategy in patients with CKD. This review also discusses therapeutic options, such as prebiotics, probiotics and natural products, for targeting dysbiosis of gut microbiota in patients to provide more specific concept-driven therapy strategy for CKD treatment.

Convection volume, β2-microglobulin and α1-microglobulin reduction ratios, and body composition in predilution online haemodiafiltration

AIM

The effect of convection volume (CV) in patients on predilution online haemodiafiltration (Pre-OL-HDF) was evaluated.

METHODS

We conducted a retrospective, cross-sectional study in 126 patients on Pre-OL-HDF. Dialysis conditions, laboratory data, and same day post-dialysis body composition measurements using bioimpedance spectroscopy were assessed. Patients were divided into two groups according to their CV: ≥ median value and < median value. Linear regression analyses for reduction ratios (RRs) of β2-microglobulin and α1-microglobulin, and body composition, were conducted.

RESULTS

Age, dialysis vintage, and CVs of the study patients were 64 ± 12 years, 81 (48-154) months, and 43.2 (38.5-55.9) L/session, respectively. The higher CV (≥ 43 L/session) group (n=66) had significantly higher RRs of β2-microglobulin and α1-microglobulin, lean tissue index, body cell mass index, total body water (TBW), extracellular water (ECW), and intracellular water (ICW) compared with the lower CV (< 43 L/session) group (n = 60; P < 0.01). Serum albumin and fat tissue index were not significantly different between the groups. CV/ECW, CV/TBW, and CV/ICW but not un-adjusted CV, were significant determinants for β2-microglobulin and α1-microglobulin RRs (P < 0.05). Lean tissue and body cell mass indexes, but not the fat tissue index, showed significant associations with CV, and RRs of β2-microglobulin and α1-microglobulin (P < 0.05).

CONCLUSIONS

Among patients on Pre-OL-HDF, higher values in the lean tissue index and body cell mass index were observed in those with higher CV versus lower CV, and CV adjusted to body water may be useful to prescribe individualized conditions for Pre-OL-HDF. This article is protected by copyright. All rights reserved.

Effects of Medium Cut-Off Versus High-Flux Hemodialysis Membranes on Biomarkers: A Systematic Review and Meta-Analysis

BACKGROUND

Medium cut-off (MCO) membranes enhance large middle-molecule clearance while selectively retaining molecules >45 000 Da.

OBJECTIVES

We undertook a systematic review and meta-analysis comparing the effects of MCO versus high-flux membranes on biomarkers.

METHODS

We searched MEDLINE, Embase, CINAHL, Cochrane Library, and Web of Science from January 2015 to July 2020, and gray literature sources from 2017. We included randomized (RS) and nonrandomized studies (NRS) comparing MCO and high-flux membranes in adults (>18 years) receiving maintenance hemodialysis. We performed study selection, data extraction, and quality appraisals in duplicate and used the Grading of Recommendations Assessment, Development, and Evaluation framework. Outcomes included solute removal (plasma clearance or dialysate quantitation), reduction ratios, and predialysis serum concentrations for a range of prespecified large middle molecules.

RESULTS

We identified 26 eligible studies (10 RS and 16 NRS; N = 1883 patients; patient-years = 1366.3). The mean difference (MD) for albumin removal was 2.31 g per session (95% confidence interval [CI], 2.79 to 1.83; high certainty), with a reduction in predialysis albumin of -0.12 g/dl (95% CI, -0.16 to -0.07; I 2 = 0%; high certainty) in the first 24 weeks, returning to normal (MD = -0.02 g/dl, 95% CI, -0.07 to -0.03; I 2 = 56%; high certainty) after 24 weeks. We also found with high certainty that MCO dialysis resulted in a large increase (standardized mean difference [SMD]> 2.0 for all) in β2-microglobulin, κ- and λ-free light chains, and myoglobin removal, resulting in moderate (SMD > 0.5) to large (SMD > 0.8) reductions in predialysis concentrations for all of these solutes. Medium cut-off dialysis increased the reduction ratio for tumor necrosis factor-alpha (TNF-α) by 7.7% (95% CI, 4.7 to 10.6; moderate certainty), and reduced predialysis TNF-α by SMD -0.48 (95% CI, -0.91 to -0.04; moderate certainty). We found with moderate certainty that MCO dialysis had little to no effect on predialysis interleukin-6 (IL-6) plasma concentrations. Medium cut-off dialysis reduced mRNA expression of TNF-α and IL-6 in peripheral leukocytes by MD -15% (95% CI, -19.6 to -10.4; moderate certainty) and -8.8% (95% CI, -10.2 to -7.4; moderate certainty), respectively.

CONCLUSION

Medium cut-off dialysis increases the clearance of a wide range of large middle molecules and likely reduces inflammatory mediators with a concomitant transient reduction in serum albumin concentration. The net effect of MCO dialysis on large middle molecules could translate into important clinical effects.

Clinical relevance of abstruse transport phenomena in haemodialysis

Haemodialysis (HD) utilizes the bidirectional properties of semipermeable membranes to remove uraemic toxins from blood while simultaneously replenishing electrolytes and buffers to correct metabolic acidosis. However, the nonspecific size-dependent transport across membranes also means that certain useful plasma constituents may be removed from the patient (together with uraemic toxins), or toxic compounds, e.g. endotoxin fragments, may accompany electrolytes and buffers of the dialysis fluids into blood and elicit severe biological reactions. We describe the mechanisms and implications of these undesirable transport processes that are inherent to all HD therapies and propose approaches to mitigate the effects of such transport. We focus particularly on two undesirable events that are considered to adversely affect HD therapy and possibly impact patient outcomes. Firstly, we describe how loss of albumin (and other essential substances) can occur while striving to eliminate larger uraemic toxins during HD and why hypoalbuminemia is a clinical condition to contend with. Secondly, we describe the origins and mode of transport of biologically active substances (from dialysis fluids with bacterial contamination) into the blood compartment and biological reactions they elicit. Endotoxin fragments activate various proinflammatory pathways to increase the underlying inflammation associated with chronic kidney disease. Both phenomena involve the physical as well as chemical properties of membranes that must be selected judiciously to balance the benefits with potential risks patients may encounter, in both the short and long term.

Efficacy of medium cut-off dialyzers and comparison with high-flux dialyzers in patients on maintenance hemodialysis: A systematic review and meta-analysis

Medium cut‐off (MCO) dialyzers were designed to provide better clearance of uremic toxins. We conducted a meta‐analysis comparing MCO with high‐flux (HF) dialyzers for the effect on uremic toxins in maintenance hemodialysis (HD) patients. Five databases were systematically searched for relevant studies and nine studies were identified finally. Reduction ratio (RR) of urea, urea, creatinine, β2‐macroglobulin (β2‐MG), kappa free light chain (κFLC), and lambda FLC (λFLC) levels were not significantly different between MCO and HF dialyzers. But RR of β2‐MG, κFLC, and λFLC were greater for MCO than HF dialyzers. MCO dialyzers could better reduce tumor necrosis factor‐α (TNF‐α) levels. Subgroup analysis stratified by study design indicated that in randomized controlled trial (RCT) studies, albumin levels was lower in MCO than HF dialyzers group, but the two dialyzers treatments were equivalent in non‐RCT subgroup. Compared with HF dialyzers, MCO dialyzers provided higher middle‐molecules uremic toxins clearance and obviously reduced TNF‐α levels.

A Review of Commercial Developments and Recent Laboratory Research of Dialyzers and Membranes for Hemodialysis Application

Dialyzers have been commercially used for hemodialysis application since the 1950s, but progress in improving their efficiencies has never stopped over the decades. This article aims to provide an up-to-date review on the commercial developments and recent laboratory research of dialyzers for hemodialysis application and to discuss the technical aspects of dialyzer development, including hollow fiber membrane materials, dialyzer design, sterilization processes and flow simulation. The technical challenges of dialyzers are also highlighted in this review, which discusses the research areas that need to be prioritized to further improve the properties of dialyzers, such as flux, biocompatibility, flow distribution and urea clearance rate. We hope this review article can provide insights to researchers in developing/designing an ideal dialyzer that can bring the best hemodialysis treatment outcomes to kidney disease patients.

Albumin is an interface between blood plasma and cell membrane, and not just a sponge

Albumin is the most abundant protein in blood plasma and acts as a carrier for many circulating molecules. Hypoalbuminaemia, mostly caused by either renal or liver disease or malnutrition, can perturb vascular homeostasis and is involved in the development of multiple diseases. Here we review four functions of albumin and the consequences of hypoalbuminaemia on vascular homeostasis. (i) Albumin is the main determinant of plasma colloid osmotic pressure. Hypoalbuminaemia was therefore thought to be the main mechanism for oedema in nephrotic syndrome (NS), however, experimental studies showed that intrarenal mechanisms rather than hypoalbuminaemia determine formation and, in particular, maintenance of oedema. (ii) Albumin functions as an interface between lysophosphatidylcholine (LPC) and circulating factors (lipoproteins and erythrocytes) and the endothelium. Consequently, hypoalbuminaemia results in higher LPC levels in lipoproteins and erythrocyte membrane, thereby increasing atherosclerotic properties of low-density lipoprotein and blood viscosity, respectively. Furthermore, albumin dose-dependently restores LPC-induced inhibition of vasodilation. (iii) Hypoalbuminaemia impacts on vascular nitric oxide (NO) signalling by directly increasing NO production in endothelial cells, leading to reduced NO sensitivity of vascular smooth muscle cells. (iv) Lastly, albumin binds free fatty acids (FFAs). FFAs can induce vascular smooth muscle cell apoptosis, uncouple endothelial NO synthase and decrease endothelium-dependent vasodilation. Unbound FFAs can increase the formation of reactive oxygen species by mitochondrial uncoupling in multiple cell types and induce hypertriglyceridemia in NS. In conclusion, albumin acts as an interface in the circulation and hypoalbuminaemia impairs multiple aspects of vascular function that may underlie the association of hypoalbuminaemia with adverse outcomes. However, hypoalbuminaemia is not a key to oedema in NS. These insights have therapeutic implications.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Long-Term Stability and Biocompatibility of Pericardial Bioprosthetic Heart Valves

The use of bioprostheses for heart valve therapy has gradually evolved over several decades and both surgical and transcatheter devices are now highly successful. The rapid expansion of the transcatheter concept has clearly placed a significant onus on the need for improved production methods, particularly the pre-treatment of bovine pericardium. Two of the difficulties associated with the biocompatibility of bioprosthetic valves are the possibilities of immune responses and calcification, which have led to either catastrophic failure or slow dystrophic changes. These have been addressed by evolutionary trends in cross-linking and decellularization techniques and, over the last two decades, the improvements have resulted in somewhat greater durability. However, as the need to consider the use of bioprosthetic valves in younger patients has become an important clinical and sociological issue, the requirement for even greater longevity and safety is now paramount. This is especially true with respect to potential therapies for young people who are afflicted by rheumatic heart disease, mostly in low- to middle-income countries, for whom no clinically acceptable and cost-effective treatments currently exist. To extend longevity to this new level, it has been necessary to evaluate the mechanisms of pericardium biocompatibility, with special emphasis on the interplay between cross-linking, decellularization and anti-immunogenicity processes. These mechanisms are reviewed in this paper. On the basis of a better understanding of these mechanisms, a few alternative treatment protocols have been developed in the last few years. The most promising protocol here is based on a carefully designed combination of phases of tissue-protective decellularization with a finely-titrated cross-linking sequence. Such refined protocols offer considerable potential in the progress toward superior longevity of pericardial heart valves and introduce a scientific dimension beyond the largely disappointing 'anti-calcification' treatments of past decades.

A Novel Substrate-Inspired Fluorescence-Based Albumin Detection Improves Assessment of Clinical Outcomes in Hemodialysis Patients Receiving a Nursing Nutrition Intervention

Background

Albumin level does not precisely reflect nutritional status. We aimed to investigate the impact of a nutrition intervention on hemodialysis patients by use of fluorescence-based plasma albumin (FPA) detection.

Material/Methods

Eighty patients underwent maintenance hemodialysis for more than half a year and had a mean albumin <3.5 g/dL for over 3 months. The subjects were randomly divided into either a Control Group (CG) or an Intervention Group (IG). The IG received nutritional supplementation, and the CG group received routine nutritional support for 12 months. FPA and plasma albumin (PA) concentrations were measured. The fluorescence probe 1,3-Dichloro-7-hydroxy-9,9-dimethyl-2(9H)-acridone methyl biphenyl benzoate was used in FPA detection. Quality of life was estimated using WHOQOL-BREF (Quality of Life Scale developed through the World Health Organization), the 36-Item Short-Form Survey (SF-36), and the 6-minute walking test (6MWT).

Results

After a 6-month and a 12-month intervention, PA and FPA concentrations increased, and the increase in FPA concentration was higher than that of PA in the IG group (P<0.05). Comparatively, the parameters of quality of life and 6MWT were improved in the IG group (P<0.05) but there were only minor changes in the CG group (P>0.05). There is an obvious association between the changes in FPA concentration and the parameters of quality of life and 6MWT but not PA.

Conclusions

Use of the fluorescence probe improves the detection sensitivity of plasma albumin and provides a potential method to assess clinical outcomes in hemodialysis patients.

Prognostic Value of Albumin to D-Dimer Ratio in Advanced Gastric Cancer

Gastric cancer (GC) is one of the most common malignancies worldwide. Notably, patients with advanced GC have a poor prognosis and quality of life, prompting the need for further studies on its prognostic markers. Among these, albumin and D-dimer are often used as prognostic factors in the prediction of a variety of tumors. Moreover, the albumin to D-dimer ratio (ADR) may be an improved predictor of chemotherapy effect and survival compared to albumin and D-dimer alone, but few studies have investigated this issue. Thus, we explored the relationship between pretreatment ADR and prognosis in advanced GC treated with first-line chemotherapy. A total of 247 advanced unresectable GC patients treated with first-line chemotherapy were retrospectively included. The cut-off value for ADR was determined using the receiver operating characteristic (ROC) curve. The ADR had a cut-off value of 41.64. Compared to albumin and D-dimer alone, ADR had the highest area under curve (AUC) value (AUC = 0.730), followed by albumin (AUC = 0.659) and D-dimer (AUC = 0.719). Additionally, we found that patients with a low ADR (<41.64) had a lower disease control rate (77.9% vs. 92.5%, P < 0.01), shorter overall survival (OS) (271 vs. 389 days), and shorter progression-free survival (PFS) (118 vs. 192 days) than patients with a high ADR (≥41.64). Similar results were also found on subgroup analysis, and ADR was found to be an independent advanced GC prognostic factor on multivariate analysis (all P < 0.001). Low ADR was found to be correlated with poor therapeutic effects of chemotherapy and shortened OS and PFS. Therefore, pretreatment ADR may be a useful tool for predicting the effect of chemotherapy and prognosis in advanced GC patients treated with first-line chemotherapy.

Slipping Through the Pores: Hypoalbuminemia and Albumin Loss During Hemodialysis

Hypoalbuminemia results when compensatory mechanisms are unable to keep pace with derangements in catabolism/loss and/or decreased synthesis of albumin. Across many disease states, including chronic kidney disease (CKD), hypoalbuminemia is a well-established, independent risk factor for adverse outcomes, including mortality. In the setting of CKD, reduced serum albumin concentrations are often a manifestation of protein-energy wasting, a state of metabolic and nutritional alterations resulting in reduced protein and energy stores. The progression of CKD to kidney failure and the initiation of maintenance hemodialysis (HD) further predisposes an already at-risk population toward hypoalbuminemia such that approximately 60% of HD patients have albumin concentrations <4.0 g/dl. Albumin loss into the dialysate through the dialyzer appears to be a potentially modifiable cause of hypoalbuminemia in some patients. A group of newer dialyzers for maintenance HD-sometimes termed protein-leaking or medium cut-off membranes-aim to improve clearance of middle molecules (vs high flux dialyzers) but are associated with increased albumin losses. In this article, we will examine the impact of dialyzer selection on albumin losses during conventional HD, including the clinical relevance of such losses on serum albumin levels. Data on the clinical relevance of albumin losses during dialysis and current gaps in the evidence base are also discussed.

How to Overcome Anabolic Resistance in Dialysis-Treated Patients?

A current hypothesis is that dialysis-treated patients are "anabolic resistant" i. e., their muscle protein synthesis (MPS) response to anabolic stimuli is blunted, an effect which leads to muscle wasting and poor physical performance in aging and in several chronic diseases. The importance of maintaining muscle mass and MPS is often neglected in dialysis-treated patients; better than to describe mechanisms leading to energy-protein wasting, the aim of this narrative review is to suggest possible strategies to overcome anabolic resistance in this patient's category. Food intake, in particular dietary protein, and physical activity, are the two major anabolic stimuli. Unfortunately, dialysis patients are often aged and have a sedentary behavior, all conditions which per se may induce a state of "anabolic resistance." In addition, patients on dialysis are exposed to amino acid or protein deprivation during the dialysis sessions. Unfortunately, the optimal amount and formula of protein/amino acid composition in supplements to maximixe MPS is still unknown in dialysis patients. In young healthy subjects, 20 g whey protein maximally stimulate MPS. However, recent observations suggest that dialysis patients need greater amounts of proteins than healthy subjects to maximally stimulate MPS. Since unneccesary amounts of amino acids could stimulate ureagenesis, toxins and acid production, it is urgent to obtain information on the optimal dose of proteins or amino acids/ketoacids to maximize MPS in this patients' population. In the meantime, the issue of maintaining muscle mass and function in dialysis-treated CKD patients needs not to be overlooked by the kidney community.

Relationship between serum total carbon dioxide concentration and bicarbonate concentration in patients undergoing hemodialysis

Background

Few studies have investigated the relationship between serum total carbon dioxide (CO₂) concentration and bicarbonate ion (HCO₃^-) concentration in patients undergoing hemodialysis. We determined the agreement and discrepancy between serum total CO₂ and HCO₃^- concentrations and the diagnostic accuracy of serum total CO₂ for the prediction of low (HCO₃^- < 24 mEq/L) and high (HCO₃^- ≥ 24 mEq/L) bicarbonate concentrations in hemodialysis patients.

Methods

One hundred forty-nine arteriovenous blood samples from 84 hemodialysis patients were studied. Multiple linear regression analysis was used to determine factors correlated with HCO₃^- concentration. Diagnostic accuracy of serum total CO₂ was evaluated using receiver operating characteristic curve analysis and a 2 × 2 table. Agreement between serum total CO₂ and HCO₃^- concentrations was assessed using Bland-Altman analysis.

Results

Serum total CO₂ concentration was closely correlated with HCO₃^- concentration (β = 0.858, P < 0.001). Area under the curve of serum total CO₂ for the identification of low and high bicarbonate concentrations was 0.989. Use of serum total CO₂ to predict low and high bicarbonate concentrations had a sensitivity of 100%, specificity of 50.0%, positive predictive value of 96.5%, negative predictive value of 100%, and accuracy of 96.6%. Bland-Altman analysis showed moderate agreement between serum total CO₂ and HCO₃^- concentrations. Discrepancies between HCO₃^- and serum total CO₂ concentrations (serum total CO₂ - HCO₃^- ≤ -1) were observed in 89 samples.

Conclusion

Serum total CO₂ concentration is closely correlated with HCO₃^- concentration in hemodialysis patients. However, there is a non-negligible discrepancy between serum total CO₂ and HCO₃^- concentrations.

Understanding Development of Malnutrition in Hemodialysis Patients: A Narrative Review

Hemodialysis (HD) majorly represents the global treatment option for patients with chronic kidney disease stage 5, and, despite advances in dialysis technology, these patients face a high risk of morbidity and mortality from malnutrition. We aimed to provide a novel view that malnutrition susceptibility in the global HD community is either or both of iatrogenic and of non-iatrogenic origins. This categorization of malnutrition origin clearly describes the role of each factor in contributing to malnutrition. Low dialysis adequacy resulting in uremia and metabolic acidosis and dialysis membranes and techniques, which incur greater amino-acid losses, are identified modifiable iatrogenic factors of malnutrition. Dietary inadequacy as per suboptimal energy and protein intakes due to poor appetite status, low diet quality, high diet monotony index, and/or psychosocial and financial barriers are modifiable non-iatrogenic factors implicated in malnutrition in these patients. These factors should be included in a comprehensive nutritional assessment for malnutrition risk. Leveraging the point of origin of malnutrition in dialysis patients is crucial for healthcare practitioners to enable personalized patient care, as well as determine country-specific malnutrition treatment strategies.

Intravascular albumin loss is strongly associated with plasma volume withdrawal in dialysis patients

INTRODUCTION

Low circulating albumin closely predicts mortality in end-stage renal disease (ESRD) patients. The cause(s) of hypoalbuminemia (hALB) in ESRD patients remains to be elucidated. The aim of the present study was to determine the role of plasma volume (PV) withdrawal in the reduction of total circulating albumin and essential blood solutes induced by hemodialysis (HD).

METHODS

PV determined with high-precision automated carbon monoxide-rebreathing, total circulating as well as concentration of plasma albumin and electrolytes were assessed prior to and after 4-hour HD in 10 ESRD patients.

FINDINGS

Baseline PV ranged from 3.5 to 6.2 l. After HD, PV was decreased by 689 ± 566 mL (-16%) (P = 0.004). Total circulating albumin was largely reduced after HD (170.8 ± 35.1 vs. 146.1 ± 48.9 g, P = 0.008), while albumin concentration was unaltered. According to a strong linear relationship (r = 0.91, P < 0.001), one-third of total circulating albumin is lost from the intravascular compartment for every liter of PV removed. Similar results were found regarding Na⁺ and Ca²⁺ electrolytes.

DISCUSSION

Total circulating albumin, but not albumin concentration, is substantially reduced by HD in proportion to the amount of PV removed from the circulation. This study highlights the potential contributing role of PV withdrawal to hALB in ESRD patients.

Comparison of the removal of uraemic toxins with medium cut-off and high-flux dialysers: a randomized clinical trial

BACKGROUND

Accumulation of middle-weight uraemic toxins in haemodialysis (HD) patients results in increased morbidity and mortality. Whether medium cut-off HD (MCO-HD) improves removal of middle-weight uraemic toxins remains to be demonstrated.

METHODS

This cross-over prospective study included 40 patients randomly assigned to receive either 3 months of MCO-HD followed by 3 months of high-flux HD (HF-HD), or vice versa. The primary endpoint was myoglobin reduction ratio (RR) after 3 months of MCO-HD. Secondary endpoints were the effect of MCO-HD on other middle-weight toxins and protein-bound toxins, and on parameters of nutrition, inflammation, anaemia and oxidative stress.

RESULTS

Compared with HF-HD, MCO-HD provided higher mean RR of myoglobin (36 ± 8 versus 57 ± 13%, P < 0.0001), beta2-microglobulin (68 ± 6 versus 73 ± 15%, P = 0.04), prolactin (32 ± 13 versus 59 ± 11%, P < 0.0001), fibroblast growth factor 23 (20 ± 21 versus 41 ± 22%, P = 0.0002), homocysteine (43 ± 7 versus 46 ± 9%, P = 0.03) and higher median RR of kappa [54 (48-58) versus 70 (63-74)%, P < 0.0001] and lambda free light chain (FLC) [15 (9-22) versus 44 (38-49)%, P < 0.0001]. Mean ± SD pre-dialysis levels of beta2-microglobulin (28.4 ± 5.6 versus 26.9 ± 5.1 mg/L, P = 0.01) and oxidized low-density lipoprote (6.9 ± 4.4 versus 5.5 ± 2.5 pg/mL, P = 0.04), and median (interquartile range) kappa FLC [145 (104-203) versus 129 (109-190) mg/L, P < 0.03] and lambda FLC [106 (77-132) versus 89 (62-125) mg/L, P = 0.002] were significantly lower. Mean albumin levels decreased significantly (38.2 ± 4.1 versus 36.9 ± 4.3 g/L, P = 0.004), without an effect on nutritional status as suggested by unchanged normalized protein catabolic rate and transthyretin level.

CONCLUSIONS

Compared with HF-HD, MCO-HD provides higher myoglobin and other middle molecules RR and is associated with moderate hypoalbuminemia. The potential benefits of this strategy on long-term clinical outcomes deserve further evaluation.

Comparison of Circulating Levels of Uremic Toxins in Hemodialysis Patients Treated with Medium Cut-Off Membranes and High-Flux Membranes: Theranova in Sisli Hamidiye Etfal (THE SHE) Randomized Control Study

INTRODUCTION

Removal of uremic toxins is a main objective of hemodialysis; however, whether high-flux and medium cut-off (MCO) membranes differ as regards removal of middle and large uremic toxins is not clear.

OBJECTIVE

To compare medium cut-off and high-flux dialyzers as regards their intra- and interdialysis effect on circulating levels of middle and large uremic toxins and serum albumin.

METHODS

Fifty-two patients were randomized to have hemodialysis with either 3 months of high-flux dialyzer followed by 3 months of MCO or vice versa. Blood samples were taken before and after dialysis at the first and last sessions of each dialyzer for analyses of middle and large uremic toxins including inflammatory mediators and vascular endothelial growth factor (VEGF), and serum albumin.

RESULTS

Reduction rates were higher, and postdialysis levels of β-2 microglobulin, free kappa and lambda light chains, and myoglobulin were lower at the first and last sessions with MCO dialyzers compared to high-flux dialyzers (p < 0.05 for all). Last session predialysis levels of β-2 microglobulin, free kappa light chain, and free lambda light chain were lower than first session predialysis levels in MCO dialyzers as compared to high-flux dialyzers (p < 0.05 for all). Last session levels of interleukin-6, interleukin-10, interleukin-17, and interferon-gamma did not differ between dialyzers (p > 0.05 for all). VEGF level was lower in the MCO group compared to the high-flux group (p = 0.043). Last session level of serum albumin with MCO dialyzers was lower than that with high-flux dialyzers (3.62 [3.45-3.88] vs. 3.78 [3.58-4.02] g/L) (p = 0.04) and 6.7% lower (p < 0.001) than at the first session of MCO dialyzers.

CONCLUSION

The decline in circulating levels of several middle and large uremic toxins including VEGF following hemodialysis was more pronounced when using MCO membranes as compared to high-flux membranes while their effect on inflammatory molecules was similar.

The Dialyzer Identification Code (DIC): A filter characteristics codification for dialyzer choice in renal replacement therapy

The dialyzer is the core element of extracorporeal blood purification therapies where several processes take place depending on specific membrane characteristics. To date, the filter choice requires preliminary knowledge of all its characteristics as they cannot be easily deduced from the commercial trade name, hence the difficulty in identifying easily equivalent dialyzers and clearly comparing single-filter characteristics. The choice of improper dialyzers for a specific treatment can determine a less-effective blood purification and potentially harmful treatments. We aimed to propose a univocal and standardized alphanumeric string to summarize essential filter properties in the Dialyzer Identification Code (DIC). DIC clearly describes device characteristics and allows to compare different dialyzer performances without resorting to the technical data sheets. Therefore, the presence of the DIC on every device facilitates information retrieval on the dialyzer, its intended use, and can facilitate matching the dialysis modality to correct dialyzers achieving a personalized renal replacement therapy. The standard filter characteristics codification by the DIC may further optimize correct extracorporeal blood purification prescriptions and the use of equivalent filters from different providers avoiding treatment inefficiency, clinical complications, and improving patient safety.

Super high-flux hemodialysis provides comparable effectiveness with high-volume postdilution online hemodiafiltration in removing protein-bound and middle-molecule uremic toxins: A prospective cross-over randomized controlled trial

Although high-volume postdilution online hemodiafiltration (ol-HDF) is superior to high-flux HD in removing all kinds of uremic toxins and improving survival, this treatment is not available in most HD centers. The present study was conducted to compare the effectiveness in removals of protein-bound (indoxyl sulfate [IS]), middle-molecule [beta-2 microglobulin (B2M) and alpha-1 microglobulin (A1MG)], and small-molecule uremic toxins between super high-flux HD (SHF-HD), HD with a novel SHF dialyzer and high-volume postdilution ol-HDF in a noninferiority fashion. Fifteen prevalent HD patients were randomly allocated into two sequences of 12-week treatment periods of SHF-HD treatment and later high-volume postdilution ol-HDF period or vice versa. Each treatment period was divided by a wash-out phase of 4-week high-flux HD. Twelve of 15 patients could complete the study. When compared with high-volume postdilution ol-HDF (convective volume of 24.4 ± 3.52 L), SHF-HD provided comparable reduction ratio values of IS, B2M, and A1MG with mean difference of 5.87 (95% confidence interval [CI] -1.63, 13.37), 1.98 (95% CI,-0.21, 4.18), and 22.96 (95% CI, -1.91, 47.83), respectively. The spKt/Vurea was not different. The predialysis levels of all uremic toxins at baseline and after 12-week treatment did not differ between both groups. Although albumin loss in dialysate in SHF-HD was greater than high-volume postdilution ol-HDF, the serum albumin levels after 12-week SHF-HD treatment were significantly higher than baseline. In conclusion, SHF-HD provides noninferior effectiveness to high-volume postdilution ol-HDF in removing various uremic toxins with significantly increased serum albumin levels despite higher albumin loss. SHF-HD might be an effectively alternative treatment when high-volume postdilution ol-HDF is not available.

Protein-Bound Uremic Toxins in Hemodialysis Patients Relate to Residual Kidney Function, Are Not Influenced by Convective Transport, and Do Not Relate to Outcome

Protein-bound uremic toxins (PBUTs) are predominantly excreted by renal tubular secretion and hardly removed by traditional hemodialysis (HD). Accumulation of PBUTs is proposed to contribute to the increased morbidity and mortality of patients with end-stage kidney disease (ESKD). Preserved PBUT excretion in patients with residual kidney function (RKF) and/or increased PBUT clearance with improved dialysis techniques might improve the prognosis of patients with ESKD. The aims of this study are to explore determinants of PBUTs in HD patients, and investigate whether hemodiafiltration (HDF) lowers PBUT plasma concentrations, and whether PBUTs are related to the outcome. Predialysis total plasma concentrations of kynurenine, kynurenic acid, indoxyl sulfate, indole-3-acetic acid, p-cresyl sulfate, p-cresyl glucuronide, and hippuric acid were measured by UHPLC-MS at baseline and after 6 months of follow-up in the first 80 patients participating in the CONvective TRAnsport Study (CONTRAST), a randomized controlled trial that compared the effects of online HDF versus low-flux HD on all-cause mortality and new cardiovascular events. RKF was inversely related to kynurenic acid (p < 0.001), indoxyl sulfate (p = 0.001), indole-3-acetic acid (p = 0.024), p-cresyl glucuronide (p = 0.004) and hippuric acid (p < 0.001) plasma concentrations. Only indoxyl sulfate decreased by 8.0% (−15.3 to 34.6) in patients treated with HDF and increased by 11.9% (−15.4 to 31.9) in HD patients after 6 months of follow-up (HDF vs. HD: p = 0.045). No independent associations were found between PBUT plasma concentrations and either risk of all-cause mortality or new cardiovascular events. In summary, in the current population, RKF is an important determinant of PBUT plasma concentrations in HD patients. The addition of convective transport did not consistently decrease PBUT plasma concentrations and no relation was found between PBUTs and cardiovascular endpoints.

Nocturnal home hemodialysis in children: Advantages, implementation, and barriers

Chronic kidney disease and end-stage renal disease (ESRD) in children are major health concerns worldwide with increasing incidence and prevalence. Renal replacement therapies and kidney transplants have remarkably improved the management of patients with ESRD in both adult and pediatric populations. Kidney transplant has the best patient outcomes, but many a time it has a considerable waiting period. In the meantime, the majority of patients with pediatric ESRD are dependent on dialysis. The conventionally utilized hemodialysis regimen is the three times weekly, in-center hemodialysis. Many studies have demonstrated the unfavorable long-term morbidity associated with the conventional regimen. Intensified dialysis programs, which include extended nocturnal hemodialysis or short daily hemodialysis, are being increasingly advocated over the past two decades. In addition to having much better clinical outcomes as compared with the conventional regimen, the flexibility to provide dialysis at home serves as a great incentive. PubMed/Medline, Embase and Cochrane databases for literature on nocturnal home hemodialysis in children with ESRD were extensively searched. Contrary to the noticeable literature available on adult home hemodialysis, a small number of studies exist in the pediatric population. In this review, the benefits, implementation and associated barriers of nocturnal home hemodialysis in children were addressed.

Albumin losses during hemodiafiltration: all dialyzers are not created equal - a case report

Background

Online hemodiafiltration (OL-HDF) is associated with better removal of both small and middle molecules and might improve survival compared to conventional hemodialysis (HD). Nevertheless, hemodiafiltration (HDF) can lead to an increase in albumin loss across the dialyzer, especially with high permeability membrane and high convective volume (CV). We present the case of a patient treated by OL-HDF who developed severe hypoalbuminemia resulting from massive albumin loss into dialysate.

Case presentation

A 71-year-old woman with ESRD started renal replacement therapy in December 2016. She was treated by high volume post-dilution OL-HDF, 4 h, 3 times per week. The dialyzer was the Phylther HF20SD (a 2.0m² heat sterilized high flux (HF) polyphenylene membrane from Bellco). At the initiation of dialysis, the serum albumin was 4.0 g/dl. During the following months, the patient developed severe hypoalbuminemia. The lowest value observed was 2.26 g/dl in July 2017. Diagnostic workup excluded nephrotic syndrome, hepatic failure and malabsorption. The patient was shifted from OL-HDF to standard HF HD, keeping the same dialyzer and dialysis schedule. During the following months, we observed a progressive correction of the hypoalbuminemia (3.82 g/dl at last follow-up). To precise the impact of the epuration technique on the albumin losses in this patient, we measured the amount of albumin in dialysate during one session with the Phylther HF20SD on OL-HDF and one session with the same filter but on standard HD. The CV was 29.0 l for the HDF session. The total albumin losses were 23.6 g on OL-HDF and 4.6 g on HD.

Conclusion

OL-HDF can lead to significant albumin loss into the dialysate, especially with high permeability membrane and high CV. When prescribing post-dilutional OL-HDF, the choice of the dialyzer membrane should be made with caution. Users of the steam sterilized polyphenylene membrane, the Phylther SD, should be informed of the risk of large albumin loss with this membrane during post-dilution OL-HDF.

Differences in Amino Acid Loss Between High-Efficiency Hemodialysis and Postdilution and Predilution Hemodiafiltration Using High Convection Volume Exchange-A New Metabolic Scenario? A Pilot Study

OBJECTIVE

The objective of the study was to quantify the loss of total amino acids (TAAs), nonessential amino acids, essential amino acids, and branched chain amino acids (BCAAs) produced by high-efficiency hemodialysis (HEHD), postdilution hemodiafiltration (HDFpost), and predilution hemodiafiltration (HDFpre) using high ultrafiltration volumes; and to define the specific AA losses registered in HEHD, HDFpost, and HDFpre; to identify a potential metabolic and nutritional decline into protein energy wasting; to compare AA analysis of arterial blood samples taken from healthy controls and patients with end-stage renal disease undergoing hemodialysis.

DESIGN AND METHODS

Identical dialysis monitors, membranes, and dialysate/infusate were used to homogenize extracorporeal body influence. Ten patients were recruited and randomized to receive treatment with HEHD, HDFpost, and HDFpre it was used on-line dialytic water methodologies (OL); patients' AA arterial concentrations were measured at the start and on completion of dialysis; TAA from the dialyzer filter was calculated, and baseline levels were subsequently compared with findings obtained 1 year later. Finally, the results obtained were compared with the data from a study of 8 healthy volunteers conducted using bioimpedance analysis and laboratory blood tests to assess nutritional status.

RESULTS

A higher convective dose results in a higher weekly loss of TAA, nonessential AAs, essential AAs, and BCAAs (HEHD: 15.7 g; HDFpost-OL: 16.1 g; HDFpre-OL: 16.3 g, P < .01). After 12 months, the same hemodialys patients showed a reduced body and water intracellular mass and reduced phase angle. Arterial concentrations of TAAs and BCAAs were lower than those detected in healthy subjects (P < .01).

CONCLUSION

The study shows that the AA losses in dialytic liquid are greater after high exchange volume HDF techniques, especially HDFpre. The AA losses are not metabolically compensated, so these increase the derangements of predialytic arterial plasma AA levels. Both AA losses and arterial AA perturbations further worsened body composition already after 12 months of additional dialysis.