First-year profile of biomarkers for early detection of renal injury in infants with congenital urinary tract obstruction.

BACKGROUND: Diagnosis of renal function impairment and deterioration in congenital urinary tract obstruction (UTO) continues to be extremely challenging. Use of renal biomarkers in this setting may favor early renal injury detection, allowing for a reliable choice of optimal therapeutic options and prevention or minimization of definitive renal damage.

METHODS: This longitudinal, prospective study analyzed the first-year profile of two serum renal biomarkers: creatinine (sCr) and cystatin C (sCyC); and six urinary renal biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), transforming growth factor beta-1 (TGF-β1), retinol-binding protein (RBP), cystatin C (uCyC), and microalbuminuria (μALB) in a cohort of 37 infants with UTO divided into three subgroups: 14/37 with unilateral hydro(uretero)nephrosis, 13/37 with bilateral hydro(uretero)nephrosis, and 10/37 patients with lower urinary tract obstruction (LUTO), compared with 24 healthy infants matched by gestational age and birth weight.

RESULTS: All urine biomarkers showed significantly higher values at the first month of life (p ≤ 0.009), while NGAL (p = 0.005), TGF-ß1 (p < 0.001), and μALB (p < 0.001) were high since birth compared to controls. Best single biomarker performances were RBP in bilateral hydronephrosis and LUTO subgroups and KIM-1 in unilateral hydronephrosis subgroup. Best biomarker combination results for all subgroups were obtained by matching RBP with TGF-ß1 or KIM-1 and NGAL with CyC ([AUC] ≤ 0.934; sensitivity ≤ 92.4%; specificity ≤ 92.8%).

CONCLUSIONS: RBP, NGAL, KIM-1, TGF-ß1, and CyC, alone and especially in combination, are relatively efficient in identifying surgically amenable congenital UTO and could be of practical use in indicating on-time surgery.