Distinct Solute Removal Patterns by Similar Surface High-Flux Membranes in Haemodiafiltration: The Adsorption Point of View

Gómez, Miquel; Bañón-Maneus, Elisenda; Arias‐Guillén, Marta; Fontseré, Néstor; Broseta, José Jesús; Ojeda, Raquel; Maduell, Francisco

doi:10.1159/000514936

Cited by 3 publications

(2 citation statements)

References 51 publications

(49 reference statements)

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“…No relevant technique, however, has been reported to characterize the membrane structure quantitatively beyond the direct observation by using scanning electron microscope (SEM) and the use of mathematical models [17][18][19]. Moreover, since the performance of the dialyzer, especially for clearances of large solutes, is normally decreasing drastically during the treatment, we must pay a great deal of attention to the membrane fouling due to the adsorption of plasma proteins [20][21][22]. Then, the objective of this study is to devise a new in vitro evaluation technique to evaluate physicochemical structures of the membrane semi-quantitatively, before and after being fouled with aqueous albumin solution.…”

Section: Introductionmentioning

confidence: 99%

Semi-Quantitative Evaluation of Asymmetricity of Dialysis Membrane Using Forward and Backward Ultrafiltration

et al. 2022

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Performance of the dialysis membrane is strongly dependent upon the physicochemical structure of the membrane. The objective of this study is to devise a new in vitro evaluation technique to quantify the physicochemical structures of the membrane. Three commercial dialyzers with cellulose triacetate (CTA), asymmetric CTA (termed ATA®), and polyether sulfone (PES) membranes (Nipro Co., Osaka, Japan) were employed for investigation. Forward and backward ultrafiltration experiments were performed separately with aqueous vitamin B12 (MW 1355), α-chymotrypsin (MW 25,000), albumin (MW 66,000) and dextran solutions, introducing the test solution inside or outside the hollow fiber (HF), respectively. Sieving coefficients (s.c.) for these solutes were measured under the test solution flow rate of 200 mL/min and the ultrafiltration rate of 10 mL/min at 310 K, according to the guidelines provided by Japanese academic societies. We defined the ratio of s.c. in the backward ultrafiltration to that in the forward ultrafiltration and termed it the index for asymmetricity (IA). The IA values were unity for vitamin B12 and α-chymotrypsin in all three of the dialyzers. The IA values for albumin, however, were 1.0 in CTA, 1.9 in ATA®, and 3.9 in PES membranes, respectively, which corresponded well with the fact that CTA is homogeneous, whereas ATA® and PES are asymmetrical in structure. Moreover, the asymmetricity of ATA® and PES may be different by twofold. This fact was verified in continuous basis by employing dextran solution before and after being fouled with albumin. These findings may contribute to the development of a novel membrane for improved success of dialysis therapy.

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Section: Introductionmentioning

confidence: 99%

Semi-Quantitative Evaluation of Asymmetricity of Dialysis Membrane Using Forward and Backward Ultrafiltration

et al. 2022

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“…The model equations were simulated with MATLAB code ODE 45 [7][8][9]. Yamamoto et al established that the Tortuous Capillary Pore Diffusion model (TCPDM) helps determine asymmetric membrane diffusive permeability [10][11][12]. Annan developed a two-dimensional mathematical model to study the blood and dialysate compartment's flow characteristics across the membrane [13,14].…”

Section: Introductionmentioning

confidence: 99%

Design and Development of a Computational Tool for a Dialyzer by Using Computational Fluid Dynamic (CFD) Model

et al. 2021

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In order to reduce the hemodialysis cost and duration, an investigation of the effect of dialyzer design and process variables on the solute clearance rate is required. It is not easy to translate the in vivo transfer process with in vitro experiments, as it involves a high cost to produce various designs and membranes for the dialyzer. The primary objective of this study was the design and development of a computational tool for a dialyzer by using a computational fluid dynamic (CFD) model. Due to their complexity, only researchers with expertise in computational analysis can use dialyzer models. Therefore, COMSOL Inc. (Stockholm, Sweden) has made an application on membrane dialysis to study the impact of different design and process parameters on dialyzed liquid concentration. Still, membrane mathematical modeling is not considered in this application. This void hinders an investigation of the impact of membrane characteristics on the solute clearance rate. This study has developed a stand-alone computational tool in COMSOL Multiphysics 5.4 to fill this void. A review of the literature conducted shows that there are no suitable stand-alone computational tools for kidney dialysis. Very little work has been undertaken to validate the stand-alone computational tool. Medical staff in the hospitals require a computational tool that can be installed quickly and provide results with limited knowledge of dialysis. This work aims to construct a user-friendly computational tool to solve this problem. The development of a user-friendly stand-alone computational tool for the dialyzer is described thoroughly. This application simulates a mathematical model with the Finite Element Method using the COMSOL Multiphysics solver. The software tool is converted to a stand-alone version with the COMSOL compiler. The stand-alone computational tool provides the clearance rate of six different toxins and module packing density. Compared with the previous application, the stand-alone computational tool of membrane dialysis enables the user to investigate the impact of membrane characteristics and process parameters on the clearance rate of different solutes. The results are also inconsistent with the literature data, and the differences ranges are 0.09–6.35% and 0.22–2.63% for urea clearance rate and glucose clearance rate, respectively. Statistical analysis of the results is presented as mean with 95% confidence intervals (CIs) and p values 0.9472 and 0.833 of the urea and glucose clearance rates, respectively.

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Protein-Bound Uremic Toxins and Inflammation Process in Hemodialysis Patients: Is There a Role for Adsorption Hemodiafiltration?

Fabbrini,

Vergani,

Malinverno

et al. 2024

Blood Purif

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Introduction: Despite major advances in the field of dialysis, there are still some unmet needs such as reducing inflammation through adequate depuration. It is well known that the wide spectrum of pro-inflammatory and pro-atherosclerotic uremic toxins are inefficiently removed by current dialysis techniques. Adsorption seems to be an extra tool to remove toxins, but its effect and optimization have not been widely studied. The aim of this report is to present preliminary results regarding the possibility of performing hemodiafiltration with a highly adsorptive polymethylmethacrylate membrane. Methods: the study was first conducted in 10 patients in which the safety and feasibility of hemodiafiltration with PMMA BG-U 2.1 membrane were tested through measurement of hemolysis indices, transmembrane pressures, and dialysis adequacy. Twenty patients were prospectively observed for 18-months period in which they consecutively underwent standard hemodialysis, standard post-dilution hemodiafiltration, and polymethylmethacrylate-based post-dilution hemodiafiltration. Protein-bound uremic toxins concentrations and inflammatory markers were measured throughout the observed period. Results: HDF PMMA was inferior to HDF in convective volume, but KT/V was similar, no differences were note in operating pressures during the two treatments. During HDF PMMA period of treatment we observed a significant reduction of CPR levels, and HDF PMMA was superior to all other treatments in Hepcidin removal even if this did not significantly affect hemoglobin levels. HDF PMMA could significantly reduce Indoxyl sulfate (Indoxyl) concentration over six months period but not for p-cresyl sulfate (P-cresyl) Conclusion: PMMA BG-U 2.1 membrane can be safely and efficiently used in hemodiafiltration. Moreover, as these preliminary results show, adding adsorption properties to convection and diffusion enabled an increased removal of Indoxyl uremic toxin associated to a reduction in inflammation markers as CRP and Hepcidin without any negative impact on albumin levels.

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Distinct Solute Removal Patterns by Similar Surface High-Flux Membranes in Haemodiafiltration: The Adsorption Point of View

Cited by 3 publications

References 51 publications

Semi-Quantitative Evaluation of Asymmetricity of Dialysis Membrane Using Forward and Backward Ultrafiltration

Semi-Quantitative Evaluation of Asymmetricity of Dialysis Membrane Using Forward and Backward Ultrafiltration

Design and Development of a Computational Tool for a Dialyzer by Using Computational Fluid Dynamic (CFD) Model

Protein-Bound Uremic Toxins and Inflammation Process in Hemodialysis Patients: Is There a Role for Adsorption Hemodiafiltration?

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