Urine neutrophil gelatinase-associated lipocalin to predict acute kidney injury in preterm neonates. A pilot study.

BACKGROUND: The efficacy of urine neutrophil gelatinase-associated lipocalin (uNGAL) as an early acute kidney injury (AKI) biomarker in preterm neonates was evaluated. METHODS: Thirty-five preterm neonates were prospectively evaluated for serum creatinine (sCre)-documented AKI during the first 14 days of life. Urine samples were collected daily throughout the study period. Of the neonates evaluated, we analyzed 11 who developed AKI (cases) and an equal number of neonates without AKI (controls) matched for gestational and postnatal age (case-control study). uNGAL was measured on the day of AKI occurrence (day 0) and on the 2 days preceding the event (day -1 and day -2, respectively) using an enzyme-linked immunosorbent assay. RESULTS: Cases had significantly higher sCre levels than controls on day 0 (1.21 ± 0.48 vs. 0.83 ± 0.16 mg/dL, p =0.031) but not on days -1 and -2. Similarly, uNGAL levels (ng/mL) were significantly higher in cases than in controls only on day 0 (19.1 ± 3.5 vs. 13.3 ± 7.3, p=0.017) and not on days -1 (18.8 ± 3.4 vs. 16.3 ± 5.9, p=0.118) and -2 (19.3 ± 1.8 vs. 19.4 ± 0.8, p =0.979). The receiver operating characteristic curve analysis showed no significant ability of uNGAL to predict AKI on days -2 and -1. CONCLUSIONS: In this pilot study in preterm neonates, although uNGAL detected sCre-based AKI upon its documentation, it failed to predict its development 1-2 days earlier.

Serum and urine acute kidney injury biomarkers in asphyxiated neonates.

BACKGROUND: We evaluated serum (s) cystatin C (CysC) and neutrophil gelatinase-associated lipocalin (NGAL) and urine (u) CysC, NGAL and kidney injury molecule-1 (KIM-1) as markers of acute kidney injury (AKI) in asphyxiated neonates. METHODS: AKI biomarkers were measured in 13 asphyxiated neonates born at ≥ 36 weeks gestational age (eight with AKI and five without AKI) and 22 controls. AKI was defined as serum creatinine ≥ 1.5 mg/dl for >24 h or rising values >0.3 mg/dl from day of life (DOL) 1. Biomarkers were measured on DOL 1, 3, and 10. RESULTS: Asphyxiated neonates had significantly higher sCysC on DOL 1 as well as sNGAL and uCysC and uNGAL (standardized to urine creatinine and absolute values) than controls at all time points. Compared to controls, significantly higher sNGAL, uCysC, and uNGAL values were observed in the asphyxia-AKI and asphyxia-no AKI subgroups. Regarding uKIM-1, only the absolute values were significantly higher in asphyxiated neonates (DOL 10). sNGAL, uCyst, and uNGAL had a significant diagnostic performance as predictors AKI on DOL 1. CONCLUSIONS: sNGAL, uCysC, and uNGAL are sensitive, early AKI biomarkers, increasing significantly in asphyxiated neonates even in those not fulfilling AKI criteria. Their measurement on DOL 1 is predictive of post-asphyxia-AKI.