Urine neutrophil gelatinase-associated lipocalin (NGAL) after revascularization is indicative of renal graft recovery in children

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K. Cransberg, K. Meys, A.J.M. Zwiers, E.A.M. Cornelissen, A.H. Bouts, M Pheninckx, Y.B. de Rijke, H. de Jong, C.E.J. Sloots

Chair(s): dr. D.A. Hesselink

Thursday 9 march 2017

12:30 - 12:45h

Categories: Poster - Klinisch

Parallel session: Postersessie - Klinisch 1

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Introduction:
Ischemia-reperfusion injury of transplanted donor kidneys results in tubular injury and subsequently the release of NGAL in the urine. We hypothesized that NGAL in the postoperative urine samples of transplanted kidneys reflects graft injury.

Methods:
All children receiving a kidney transplantation at the 3 pediatric kidney transplantation centers in the Netherlands were eligible for this prospective observational study. Excluded were patients who did not have separate sampling of urine from donor kidney and native kidneys,except for patients without residual diuresis.

Urine was sampled pre-transplant, and at 3, 6, 12, 24, 36, and aiming at 48 and 72 hours post-revascularisation (RV), in separate portions from the splint (only graft urine), and from the bladder (mixed urine from native kidneys and the graft).

NGAL was assessed by immunoassay. In this study NGAL was analysed as absolute concentration. Area under Curve (AUC) and maximal concentration (Cmax) was calculated by the Microsoft based program (PK Solver).

Half-life of the serum creatinine value acquired at RV was calculated by a linear trapezoidal method from the values measured at 6, 12, 24, 36 and 60 hours after RV. eGFR at 3 months was calculated.

Data were analysed using non-parametric tests.

Results:
Sixty-six patients (37 boys; median age 10.2 yr, range 1.6-17.9) were included, of whom 15 (23%) received a deceased donor (DD) kidney and 39 (59%) had had previous dialysis treatment. Median half-life of serum creatinine was 33.6 hrs (IQR 13.5 – 109.5) for DD, and 7.8 hrs (range 5.1-12.0) for living-donor (LD) transplants No patient needed dialysis post-transplant.

Splint urinary NGAL was maximal at 3 (first sample) or 6 hours post-RV, with a median concentration of 150 ng/ml (IQR 42 – 629). Cmax was associated with creatinine half-life (p< 0.001), donor source (lower in LD,  p<0.001), but not with recipients’ age. Cmax was not predictive of eGFR at 3 months post-transplant.

The median AUC of NGAL in splint urine was 2394 uur.mcg/l (IQR 912-8086). The AUC was significantly associated with creatinine half-life (p<0.001) and donor source (p<0.001), but not with age, or eGFR at 3 months post-transplant.

Conclusion:
Especially in recipients of DD kidneys both the Cmax and the AUC of NGAL in the urine of the graft  is associated with the velocity of graft recovery.  Urine Cmax of NGAL is a promising early predictor of graft recovery.