Urine neutrophil gelatinase-associated lipocalin (uNGAL) and netrin-1: are they effectively improving the clinical management of sepsis-induced acute kidney injury (AKI)?

Neutrophil gelatinase-associated lipocalin (NGAL) and Netrin-1 have been proposed over the past years as emergent biomarkers for the early and accurate diagnosis and monitoring of acute kidney injury (AKI). During the early phases of AKI, a rapid and massive up-regulation of NGAL mRNA takes place in the thick ascending limb of Henle's loop and in the collecting ducts, and therefore, changes in urinary NGAL (uNGAL) excretion seem to be more specific than plasma NGAL in assessing early kidney injury. The availability of a new automated immunoassay for measuring uNGAL facilitates its introduction in the clinical routine, especially in an emergency setting. However, in critically ill newborns AKI often develops during sepsis, which in turn induces an up-regulation of NGAL mRNA in neutrophils. To improve the effectiveness of therapeutic treatment in septic newborns with AKI, there is the need to accurately distinguish NGAL molecular forms originating within the distal nephron from those originating from neutrophils. This concise review summarizes properties and perspectives of uNGAL and Netrin-1 for their appropriate clinical utilization.