Neutrophil gelatinase-associated lipocalin: a promising biomarker for human acute kidney injury

Abstract

Acute kidney injury (AKI) is a common and serious condition, the diagnosis of which depends on serum creatinine measurements. Unfortunately, creatinine is a delayed and unreliable indicator of AKI. The lack of early biomarkers has crippled our ability to translate promising experimental therapies to human AKI. Fortunately, understanding the early stress response of the kidney to acute injuries has revealed a number of potential biomarkers. The discovery, translation and validation of neutrophil gelatinase-associated lipocalin, arguably the most promising novel AKI biomarker, are reviewed in this article. Neutrophil gelatinase-associated lipocalin is emerging as an excellent standalone troponin-like biomarker in the plasma and urine for the prediction of AKI, monitoring clinical trials in AKI and for the prognosis of AKI in several common clinical scenarios.

Figure 1. Clinical continuum of acute kidney injury

The figure is color-coded to identify the various stages, and the biomarkers that correspond to them. AKI: Acute kidney injury; GFR: Glomerular filtration rate; NGAL: Neutrophil gelatinase-associated lipocalin.

Figure 2. Pathophysiologic continuum of acute kidney injury

The figure is color-coded to correspond to the various stages identified in Figure 1. AKI: Acute kidney injury.

Figure 3. The cellular role of neutrophil gelatinase-associated lipocalin may be dependent on the type of molecule it is complexed with

Apo-NGAL: Neutrophil gelatinase-associated lipocalin that is devoid of siderophore or iron; ECM: Extracellular matrix.

Figure 4. Plasma neutrophil gelatinase-associated lipocalin levels measured by Triage^® neutrophil gelatinase-associated lipocalin device at various time points after cardiopulmonary bypass in subjects with no acute kidney injury (N), or with acute kidney injury (R, I or F) stratified by RIFLE criteria

NGAL: Neutrophil gelatinase-associated lipocalin. Post hoc analysis of data from reference [92].

Figure 5. Urine neutrophil gelatinase-associated lipocalin levels measured by ARCHITECT^® analyzer at various time points after cardiopulmonary bypass in subjects with no acute kidney injury (N), or with acute kidney injury (R, I or F) stratified by RIFLE criteria

NGAL: Neutrophil gelatinase-associated lipocalin. Post hoc analysis of data from [93].