Effects of two low-flux cellulose acetate dialysers on plasma lipids and lipoproteins--a cross-over trial

Abstract

Background: Studies have shown a beneficial effect of high-flux dialysis on lipids, lipoproteins and lipoprotein lipase (Lpl) activity. This has been attributed to improved clearance of Lpl-inhibitory molecules of middle molecular weight, but differences in flux or biocompatibility have not been addressed. We conducted a blinded cross-over trial of two cellulose acetate dialysers (AN140, Althin Medical Inc. and CA210, Baxter Inc.) of similar flux (11 ml/h/mmHg transmembrane pressure) but with different clearances of larger molecules [AN140 sieving coefficient at mol. wt 11,000 Da (beta2-microglobulin) 0.6; CA210 sieving coefficient negligible].

Methods: Sixteen patients were divided into two groups to receive dialysis with AN140 for 1 week followed by CA210 or vice versa. Before and after the third dialysis with each membrane, plasma lipid and lipoprotein concentrations were measured. Post-dialysis post-heparin lipase activity was measured in six patients.

Results: Fifteen patients completed the study. No difference between dialysers was found for apolipoprotein (apo) A1, B or total cholesterol measurements. The rise in triglyceride post-dialysis was attenuated by AN140 (rise 0.05 +/- 0.4 mmol/l vs CA210 0.44 +/- 0.54 mmol/l, P=0.03), while high density lipoprotein (HDL) cholesterol was increased by AN140 (rise 0.18 +/- 0.12 mmol/l vs CA210 0.06 +/- 0.14 mmol/l, P<0.02). ApoE rose with AN140 during dialysis but declined with CA210 (1.10 +/- 1.06 mg/dl and -0.77 +/- 0.63 mg/dl, P=0.002) as did apoCIII (HDL) (AN140 rise 1.33 +/- 2.06 mg/dl; CA210 fall -0.67 +/- 0.73 mg/dl, P=0.001). Lpl activity, measured in six patients, tended to be higher for AN140 (45.3 +/- 10.5 mmol FFA/ml plasma/h vs CA210 (37.2 +/- 7.9 mmol FFA/ml plasma/h) (P=0.16).

Conclusions: We conclude that low-flux dialysis using a cellulose acetate membrane with good clearance of higher molecular weight molecules may be associated with beneficial changes in plasma lipids and lipoproteins.