Pyrogen Transfer across High‐ and Low‐flux Hemodialysis Membranes

Abstract

The extent to which bacterial products from contaminated dialysate enter a patient's blood depends upon the type and permeability of the hemodialysis membrane in use. This study was performed to assess the transfer of pyrogenic substances across both high- and low-flux membranes (DIAPES, Fresenius Polysulfone, Helixone, Polyamide S). All experiments were carried out in the saline-saline model. The dialysate pool was contaminated either with purified lipopolysaccharide (LPS) (250 and 500 EU/mL) or with sterile bacterial culture filtrates (20 EU/mL), and in vitro dialysis was performed under diffusive and convective conditions. A significant transfer of endotoxin was observed for both low- and high-flux DIAPES challenged with either LPS or with bacterial culture filtrates. Under identical conditions, no transfer of endotoxins was detectable across Fresenius Polysulfone and Helixone upon challenge with purified LPS. With bacterial culture filtrates, endotoxin concentrations for Polyamide S and Fresenius Polysulfone were about 10% and 1%, respectively, of those measured for DIAPES, whereas no transfer of endotoxin was detectable for Helixone. Using an alternative assay (induction of interleukin-1 receptor antagonist, IL-1Ra, in whole blood), only the DIAPES membrane showed the passage of cytokine-inducing substances. Thus, when saline is present in both the blood and dialysate compartments (i.e., the situation during predialysis priming procedures), dialysis membranes differ profoundly with respect to their permeability to endotoxins.

Protein-Leaking Membranes for Hemodialysis

“…Among other effects, bacterial products from the dialysate may stimulate an inflammatory response and compromise a patient's ability to increase albumin synthesis in response to albumin loss across the protein-leaking membrane (31). Some membrane materials provide a final barrier against endotoxin transfer into the blood by virtue of their capacity to adsorb endotoxin and endotoxin fragments (32). Finally, reuse of dialyzers that contain protein-leaking membranes should be undertaken with great care, if at all, given the documented ability of some reprocessing techniques to increase the protein permeability of some membranes (12,13,16).…”

New Ligand Coupling Procedure for Formation of an Immunoadsorption Wall

“…This inevitably entails the loss of some essential components such as albumin and increases the possibility of contamination of pyrogen from the dialysate. [23][24][25] In contrast, an immunoadsorption wall seems able to be put into clinical use without these similar problems. In fact, the rationale of a potential treatment using an immunoadsorption wall to remove toxic molecules is quite different from hemodialysis.…”

Dialysis Patients and Cardiovascular Problems: Can Technology Help Solve the Complex Equation?

“…Weber et al [39] showed that polysulfone-based membranes had a signifi cantly higher endotoxin retention compared with two polyarylethersulfone-based membranes. Likewise, Schindler et al [40] demonstrated differences in the permeability of high-fl ux dialyzer membranes for bacterial pyrogens, concluding that dialyzers that leak cytokine-inducing substances should not be used unless the dialysate has passed through an ultrafi lter.…”