Hydrophilic Modification of Dialysis Membranes Sustains Middle Molecule Removal and Filtration Characteristics

Abstract

While efficient removal of uremic toxins and accumulated water is pivotal for the well-being of dialysis patients, protein adsorption to the dialyzer membrane reduces the performance of a dialyzer. Hydrophilic membrane modification with polyvinylpyrrolidone (PVP) has been shown to reduce protein adsorption and to stabilize membrane permeability. In this study we compared middle molecule clearance and filtration performance of nine polysulfone-, polyethersulfone-, and cellulose-based dialyzers over time. Protein adsorption was simulated in recirculation experiments, while β2-microglobulin clearance as well as transmembrane pressure (TMP) and filtrate flow were determined over time. The results of this study showed that β2-microglobulin clearance (−7.2 mL/min/m2) and filtrate flow (−54.4 mL/min) decreased strongly during the first 30 min and slowly afterwards (−0.7 mL/min/m2 and −6.8 mL/min, respectively, for the next 30 min); the TMP increase (+37.2 mmHg and +8.6 mmHg, respectively) showed comparable kinetics. Across all tested dialyzers, the dialyzer with a hydrophilic modified membrane (FX CorAL) had the highest β2-microglobulin clearance after protein fouling and the most stable filtration characteristics. In conclusion, hydrophilic membrane modification with PVP stabilizes the removal capacity of middle molecules and filtration performance over time. Such dialyzers may have benefits during hemodiafiltration treatments which aim to achieve high exchange volumes.

Randomized investigation of increased dialyzer membrane hydrophilicity on hemocompatibility and performance

“…As investigational device, the trial included the novel FX CorAL dialyzer, which contains a hydrophilic membrane with increased PVP content on the blood-side surface. This study supports recent experimental studies which showed a strong correlation of hydrophilic membrane modification with reduced protein fouling, stabilized performance over time and the favorable hemocompatibility profile [ 9 , 10 , 17 , 21 ].…”

“…To overcome hydrophobicity, these membranes are often blended with hydrophilic polyvinylpyrrolidone (PVP). Increased PVP content on the membrane’s blood-side surface reduces protein adsorption to the membrane, and associates with positive effects on hemocompatibility and performance [ 9 – 17 ].…”