Differences in solute removal by two high-flux membranes of nominally similar synthetic polymers

Ouseph, Rosemary; Hutchison, Colin A.; Ward, Richard A.

doi:10.1093/ndt/gfm916

Cited by 59 publications

(42 citation statements)

References 21 publications

(21 reference statements)

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“…where Q BE is the effective blood flow rate (defined below), Q UF is the ultrafiltration rate based on weight loss, and C PW and C PWven are the arterial and venous plasma water concentrations, respectively, at the time of sampling [10] . Q BE equivalent to the plasma water flow rate ( Q PW to be used for λ FLC, α 1 -microglobulin, CFD, κ FLC, myoglobin, and β2-M) was calculated as follows:…”

Section: Study Design Patients Methodsmentioning

confidence: 99%

Effects of Hemodialysis Therapy Using Dialyzers with Medium Cut-Off Membranes on Middle Molecules

Kirsch

Rosenkranz

Lyko

et al. 2017

Contributions to Nephrology

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The removal of larger middle molecules, such as free immunoglobulin light chains (FLC), is poor with most currently used dialysis technologies. While hemodiafiltration (HDF) provides enhanced clearance of middle molecules compared to high-flux hemodialysis (HD), this technique is currently not approved in some regions and, hence, not accessible for all patients. The retention of middle molecules is thought to be one factor, which contributes to excessive morbidity and mortality in HD patients. The development of medium cut-off (MCO) dialysis membranes is aimed at a more efficient clearance of larger uremic toxins while retaining albumin and may extend the benefit of enhanced solute removal to more patients. In 2 pilot studies, the removal of middle molecules using HD with an MCO dialyzer prototype was compared to (1) high-flux HD and (2) high-flux HD and HDF. The primary outcome was the overall clearance of λ FLC, and the secondary outcome was the clearance of other middle molecules and safety. Pre-to-post reduction ratios and instantaneous clearances during HD were also assessed. In both trials, the overall λ FLC clearance with MCO HD was significantly larger than with high-flux HD and HDF. Accordingly, instantaneous clearances at 30 and 120 min showed significantly higher removal of λ FLC compared to high-flux HD and HDF. MCO HD provides a more efficient removal of larger middle molecules compared to high-flux HD and HDF. A potential drawback is slightly increased albumin loss, yet preliminary data suggest that this does not lead to perma- nently decreased albumin levels. Thus, MCO HD may present a promising approach to further improve middle molecule removal in maintenance dialysis patients and to extend its benefit to more patients. Effects of Hemodialysis Therapy

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Section: Study Design Patients Methodsmentioning

confidence: 99%

Effects of Hemodialysis Therapy Using Dialyzers with Medium Cut-Off Membranes on Middle Molecules

Kirsch

Rosenkranz

Lyko

et al. 2017

Contributions to Nephrology

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“…24,39,101,102 Furthermore, we chose not to include results on k-light chains, because the concentration found in uremic patients was less than 1% of the values previously found in healthy or CKD populations (30-80 mg/L). 60,103 Finally, because it was shown in 2005 that the reported serum p-cresol concentrations were actually caused by an artifact linked to deproteinization of p-cresylsulfate and p-cresylglucuronide, 104,105 results on p-cresol were also excluded. Still, we found eight reports on p-cresol published after 2005.…”

Section: Variability In Concentrationsmentioning

confidence: 99%

Normal and Pathologic Concentrations of Uremic Toxins

Duranton¹,

Cohen

Smet

et al. 2012

Journal of the American Society of Nephrology

811

764

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An updated review of the existing knowledge regarding uremic toxins facilitates the design of experimental studies. We performed a literature search and found 621 articles about uremic toxicity published after a 2003 review of this topic. Eighty-seven records provided serum or blood measurements of one or more solutes in patients with CKD. These records described 32 previously known uremic toxins and 56 newly reported solutes. The articles most frequently reported concentrations of b2-microglobulin, indoxyl sulfate, homocysteine, uric acid, and parathyroid hormone. We found most solutes (59%) in only one report. Compared with previous results, more recent articles reported higher uremic concentrations of many solutes, including carboxymethyllysine, cystatin C, and parathyroid hormone. However, five solutes had uremic concentrations less than 10% of the originally reported values. Furthermore, the uremic concentrations of four solutes did not exceed their respective normal concentrations, although they had been previously described as uremic retention solutes. In summary, this review extends the classification of uremic retention solutes and their normal and uremic concentrations, and it should aid the design of experiments to study the biologic effects of these solutes in CKD. The uremic syndrome is characterized by the retention of various solutes that would normally be excreted by the kidneys. The substances that interact negatively with biologic functions are called uremic toxins. In the past years, research on uremic toxicity has been very dynamic and resulted in the identification of dozens of retention solutes, including several uremic toxins. In 2003, the European Uremic Toxin Work Group (http://www.uremic-toxins.org/) proposed a classification of 90 retention solutes providing data on normal and pathologic serum concentrations. 1 In 2007, results were further discussed and expanded with the addition of 14 solutes. 2,3 This collaborative work focused on the highest mean or median concentration of the solutes measured in a uremic population and the highest individual uremic concentration. These data were particularly relevant for researchers on uremic toxicity, and they became a successful tool for allowing use of standardized and biologically relevant concentrations in experimental settings. More recently, scientific and technological progress resulted in the identification of many new uremic retention solutes, particularly thanks to nontargeted approaches such as metabolomic and proteomic profiling. 4,5 To maintain experimental guidelines in keeping with current knowledge, it seemed necessary to propose an update of the encyclopedic review.

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“…Here, the porosity values of the three layers of the membrane are used for A k . The six molecules that are considered in this paper are listed in Table 1 with their molecular weight [10], diameter [11] and diffusion coefficient. …”

Section: Equationsmentioning

confidence: 99%

Study of Dialyzer Membrane (Polyflux 210H) and Effects of Different Parameters on Dialysis Performance

Islam¹,

Szpunar²

2013

OJNeph

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Problems frequently encountered in kidney malfunction include abnormal fluid levels in the body, increased acid levels, abnormal levels of Urea, Glucose, Endothelin, β2-Microglobulin and Complement Factor D. Parameters characterizing the structure of dialyzers are very important because they decide overall clearance of toxin molecules and at the same time should allow retaining useful molecules in the blood. In this paper, a cross sectional image of the dialyzer membrane with details of the porosity is presented. A multilayered membrane model with different porosity for each layer, describes the actual structure of Polyflux 210H membrane. This model is developed using Finite Element Software-COMSOL Multiphysics 4.3. A blood flow with substances like-Urea, Glucose, Endothelin, β2-Microglobulin, Complement Factor D and Albumin is introduced. For a certain blood flow rate, the toxins diffuse through the membrane and on the other side of the membrane a dialysate flow removes the toxins. Here, different parameters, such as flow rate of blood and dialysate, length and radius of the fiber are changed to simulate how these changes affect toxin clearance and the removal of useful molecules.

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Differences in solute removal by two high-flux membranes of nominally similar synthetic polymers

Cited by 59 publications

References 21 publications

Effects of Hemodialysis Therapy Using Dialyzers with Medium Cut-Off Membranes on Middle Molecules

Effects of Hemodialysis Therapy Using Dialyzers with Medium Cut-Off Membranes on Middle Molecules

Normal and Pathologic Concentrations of Uremic Toxins

Study of Dialyzer Membrane (Polyflux 210H) and Effects of Different Parameters on Dialysis Performance

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