Investigation of renalase and catecholamine levels in serum and urine in children with ureteropelvic junction obstruction

Ureteral pelvic junction obstruction is the most common cause of hydronephrosis in children, which prevents the flow of urine from the renal pelvis to the ureter, leading to progressive kidney destruction. Ultrasonography (USG), scintigraphy studies, intravenous pyelography and magnetic resonance urography are used to diagnose obstructive uropathy. However, measuring the levels of some invasive markers such as renalase and β2 microglobulin in serum and urine has not entered into routine use. The aim of this study is to evaluate serum and urinary renalase, adrenaline and noradrenaline levels in Ureteral pelvic junction obstruction patients and compare them with a control group. In our study, 20 pediatric patients diagnosed with ureteral pelvic junction obstruction with unilateral Grade 3 and 4 hydronephrosis according to the Society for Fetal Ürology (SFU) hydronephrosis grading system who presented to the pediatric surgery outpatient clinic between December 2021 and December 2023 were evaluated. The control group consisted of healthy children aged 0-18 years who presented to the pediatric surgery outpatient clinic for circumcision without any known illness. Analysis was performed using the Statistical Package for the Social Sciences software version 22 (SPSS, Inc., USA). Mann-Whitney U test was used to compare binary groups consisting of independent continuous variables, and the chi-square test was used for categorical data analysis. p < 0.05 values were considered statistically significant. Serum and urine renalase, adrenaline and noradrenaline were examined in the patients and the control group. In our study, the serum renalase levels were higher in the patient group (15,5±15,0 ng/ml), compared to the control group (10,9±11,5 ng/ml). However, this difference was not statistically significant. In our study, the serum renalase level of patients with kidney function below %40 in DMSA (18,0±13,1 ng/ml), was higher compared to the average renalase value of patients with kidney function above %40 in DMSA (15,1±15,6 ng/ml). Similarly, in patients with Grade 4 hydronephrosis (17,2±12,5 ng/ml), the serum renalase levels were higher compared to the Grade 3 hydronephrosis patient group (13,5±18,1 ng/ml). In our study, serum renalase levels were higher in obstructive patients in DTPA (17,20,6±18,2 ng/ml), compared to non-obstructive patients (9,3±6,4 ng/ml). However, this difference was not statistically significant. As a result, further studies are needed before routine measurement of serum and urinary renalase in patients with ureteropelvic junction stenosis can be used to predict the severity of obstruction.