Uromodulin and YKL-40 as biomarkers in pediatric acute kidney injury: A review of current evidence

This review aims to discuss the current evidence about the role of two biomarkers in pediatric acute kidney injury (AKI)-uromodulin (UMOD) and YKL-40 (a glycoprotein whose name is derived from the three N-terminal amino acids present on the secreted form and its molecular size of 40 kDa). Several novel biomarkers have been used in the diagnostic and prognostic evaluation of AKI. UMOD and YKL-40 or chitinase 3-like protein 1 have recently attracted scientific interest as potential biomarkers in the disease. Although UMOD has long been recognized as a marker of tubular health, it was only in the recent past that its functional role in health and disease began to be understood. The finding of low levels of the biomarker in AKI supports the recent discovery that it plays a protective rather than an instigatory role in the disease. Evidence synthesized from the reviewed studies suggests that urine UMOD levels are negatively correlated with AKI risk. Moreover, increased serum UMOD may also be used as a prognostic biomarker for recovery from AKI. On the other hand, YKL-40 (although a multidisease biomarker) has been shown to play a predictive and prognostic role in AKI, its levels being positively correlated with disease risk. Large prospective studies are however required to confirm these results and to assess the clinical utility of estimating UMOD and YKL-40 levels as well as the therapeutic implications of their altered levels.