Effects of a polyelectrolyte additive on the selective dialysis membrane permeability for low-molecular-weight proteins.
BACKGROUND
Improving the sieving characteristics of dialysis membranes enhances the clearance of low-molecular-weight (LMW) proteins and may have an impact on outcome in patients receiving haemodialysis. To approach this goal, a novel polyelectrolyte additive process was applied to a polyethersulphone (PES) membrane.


METHODS
Polyelectrolyte-modified PES was characterized in vitro by measuring complement activation and sieving coefficients of cytochrome c and serum albumin. In a prospective, randomized, cross-over study, instantaneous plasma water clearances and reduction rates of LMW proteins [beta(2)-microglobulin (b2m), cystatin c, myoglobin, retinol binding protein] were determined in eight patients receiving dialysis treatment with PES in comparison with polysulphone (PSU). Biocompatibility was assessed by determination of transient leucopenia, plasma levels of complement C5a, thrombin-antithrombin III (TAT), myeloperoxidase (MPO) and elastase (ELT).


RESULTS
PES showed a steeper sieving profile and lower complement activation in vitro compared with PSU. Instantaneous clearance (69 +/- 8 vs. 58 +/- 3 ml/min; P < 0.001) and reduction rate (72.3 +/- 1 5% vs 66.2 +/- 6.1%; P < 0.001) of b2m were significantly higher with PES as compared with PSU. With higher molecular weight of proteins, differences in the solute removal between PES and PSU further increased, whereas albumin loss remained low (PES, 0.53 +/- 0.17 vs PSU, <0.22 g/dialysis). MPO, ELT and TAT did not differ between the two membranes. In contrast, leucopenia was less pronounced and C5a generation was significantly lower during dialysis with PES.


CONCLUSIONS
Polyelectrolyte modification of PES results in a higher LMW protein removal and in optimized biocompatibility. Whether these findings translate into better outcome of patients receiving haemodialysis requires further studies.
Krieter
Detlef H
DH
University Hospital Würzburg, Division of Nephrology, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany. krieter_d@medizin.uni-wuerzburg.de.
Morgenroth
Andreas
A
Barasinski
Artur
A
Lemke
Horst-Dieter
HD
Schuster
Oliver
O
von Harten
Bodo
B
Wanner
Christoph
C
D000818:Animals; D001672:Biocompatible Materials; D018592:Cross-Over Studies; D015314:Dialysis Solutions / Q000737:chemistry; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D010969:Plastics; D011108:Polymers; D011446:Prospective Studies; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D006435:Renal Dialysis / Q000295:instrumentation*; D012756:Sheep; D013450:Sulfones; D016896:Treatment Outcome
D001672:Biocompatible Materials; D015314:Dialysis Solutions; D008567:Membranes, Artificial; D010969:Plastics; D011108:Polymers; D011506:Proteins; D013450:Sulfones; C022840:polyether sulfone