Pyrogen retention: Comparison of the novel medium cut-off (MCO) membrane with other dialyser membranes

Abstract

Haemodialysis effectively removes small solutes and smaller-sized middle molecules from the blood; however, the clearance of larger middle molecules, which have been associated with negative effects, is poor. The novel medium cut-off (MCO) dialysis membrane has larger pore sizes and a more open structure than other high-flux membranes, providing improved removal of larger middle molecules while retaining albumin. However, larger pore sizes may potentially increase permeability to pyrogens, including endotoxins and other bacterial contaminants, that could be present in the dialysis fluid. In this study, we tested the capacity of low-flux, high-flux, MCO and high cut-off dialyser membranes with different pore sizes to prevent pyrogens crossing from dialysate to the blood side in a closed-loop test system, differentiating among lipopolysaccharides, peptidoglycans and bacterial DNA using a toll-like receptor assay. Even though the bacterial contamination levels in our test system exceeded the acceptable pyrogen dose for standard dialysis fluid, levels of lipopolysaccharides, peptidoglycans and bacterial DNA in the blood-side samples were too low to identify potential differences in pyrogen permeability among the membranes. Our results suggest that MCO membranes are suitable for haemodialysis using ISO standard dialysis fluid quality, and retain endotoxins at a similar level as other membranes.

Efficacy of Medium Cut-Off Dialyzer and Comparison with Standard High-Flux Hemodialysis

“…Another advantage of the MCO membranes lies in the usage of conventional HD treatment and equipment. These membranes are suitable for using ISO standard dialysis fluid quality and retain endotoxins at a similar level as to other membranes [31]. We performed this expanded dialysis in standard HD modality, using our regular HD equipment and water supply system.…”

Expanded Haemodialysis as a Current Strategy to Remove Uremic Toxins

“…The concerns are about an eventual chronic exposure to inflammatory products, such as cytokines, that can be induced by the increased permeability for bacterial degradation products, thus potentially contributing to the micro-inflammatory status of ESRD patients. Two studies have been performed to assess MCO safety related to microbial contamination using in vitro dialysis system [53,54]. Both of them compared LF, HF, MCO and HCO membranes.…”

Disruptive technologies for hemodialysis: medium and high cutoff membranes. Is the future now?

“…The mean pore radius is 5 nm, standard deviation 0.1 nm, for the MCO membrane, with a lower variance from the mean, i.e., more uniformity in pore dimension 27 , providing a more selective removal of solutes with reduced albumin leakage. As a comparison, the HCO membrane mean pore radius is 10 nm with a wider standard deviation (2.0 nm) 28 . Kirsch et al observed an albumin loss of 3 g in a four-hour MCO-HD session, which is similar to the loss seen in HF-HDF 17 .…”