Plasma neutrophil gelatinase-associated lipocalin clearance during venovenous hemodiafiltration

Abstract

To the Editor Plasma neutrophil gelatinase-associated lipocalin (NGAL) levels are predictors of acute kidney injury (AKI) severity [1, 2]. NGAL may also limit kidney injury [3]. Hemodiafiltration (HDF) may affect plasma NGAL levels because NGAL is probably filtered and absorbed by the filter membrane. We investigated the effect of HDF on plasma NGAL levels in eight AKI patients undergoing intermittent HDF (Osaka University Hospital Ethics Committee No. 9024). HDF by the post-dilution method was performed using an EXCELFLO AEF-10 filter (Asahi Kasei Kuraray Medical Co., Ltd., Tokyo, Japan). The blood flow rate was 80 mL/min. Plasma NGAL levels were measured using the CircuLex NGAL/Lipocalin-2 ELISA Kit (CycLex Co., Ltd. Ina, Japan) before, during, and after HDF. NGAL clearance (ClNGAL) was determined as ClNGAL = (Cpre Cpost)/Cpre 9 80 (mL/min) and the sieving coefficient (SC) as SC = 2 9 Cfil/(Cpre ? Cpost), where Cfil is the concentration in filtered fluid and Cpre and Cpost are the concentrations in preand post-filtered plasma, respectively. The interval between initial HDF and the study was 21.4 ± 24.6 days. Within this period, continuous HDF was applied for 10.1 ± 11.8 days. The total flow rate of the replacement and dialysis fluids was 21.8 ± 2.3 mL/kg/h. Plasma NGAL levels decreased significantly to 83.6 ± 5.6% (percentage of NGAL level at HDF initiation) at the end of HDF (P \ 0.001, repeated measures ANOVA) (Fig. 1). Discontinuation of HDF increased plasma NGAL levels which returned to 90.8 ± 6.3% at 17.5 ± 4.7 h.