Urinary angiotensinogen as a novel marker of obstructive nephropathy in children

Abstract

Aim: Obstructive nephropathy due to congenital or acquired urinary tract obstruction is one of the most important causes of chronic renal failure in children. There is a need for identification of new noninvasive urinary biomarkers to provide the clinician with fast, specific and reliable diagnostic and prognostic tool. The aim of the study was to determine whether urinary angiotensinogen (uAGT) may be a useful marker of obstruction in children with hydronephrosis (HN) caused by ureteropelvic junction obstruction (UPJO).

Methods: The study cohort consisted of surgical group (SG): 31 children with severe HN who required surgery; nonsurgical group (NSG): 20 patients with mild HN, and reference group (RG): 19 healthy children. Urinary concentrations of angiotensinogen were measured using immunoenzymatic ELISA commercial kit and were expressed in ng/mg Cre (uAGT/uCre).

Results: uAGT/uCre level was higher in SG when compared to NSG (p < 0.01) and healthy participants (SG vs. RG: p < 0.01). The difference between the uAGT/uCre in NSG and RG was not statistically significant (p > 0.05). uAGT/uCre was correlated negatively with differential renal function (r = -0.46; p < 0.01).

Conclusion: The present pilot study has clearly demonstrated that children with UPJO showed increased uAGT levels, which correlated negatively with differential renal function in radionuclide scan.

Keywords: Hydronephrosis; Ureteropelvic junction obstruction; Urinary angiotensinogen.