Prediction of the outcome of antenatal hydronephrosis: significance of urinary EGF

Down-regulation of epidermal growth factor (EGF) in the renal parenchyma has been demonstrated in children who underwent pyeloplasty due to ureteropelvic junction obstruction (UPJO). Urine levels of EGF were confirmed to parallel this finding before and after surgery. The aim of our study was to evaluate the relationship between urinary EGF (uEGF) concentrations and Society of Fetal Urology (SFU) high-grade hydronephrosis in infants presenting unilateral antenatal hydronephrosis (ANH).

This was a prospective study involving 45 infants (33 in the observational group, 12 in the surgical group) who presented with unilateral ANH. Postnatal evaluation included a clinical examination, renal ultrasonography, and voiding cystourethrography. Diuretic renal scans were performed in infants with an initial SFU grade 3 or 4 hydronephrosis or increasing hydronephrosis during follow-up. Pyeloplasty was performed when a well-tempered renogram showed an obstructive drainage curve with a half-life of >20 min and/or an obstructive washout curve pattern during the diuretic phase. We studied the longitudinal changes in SFU hydronephrosis grade and uEGF in each group and compared concentration levels at three time points in both groups. The enzyme-linked immunosorbent assay (ELISA) method was used to measure EGF concentrations in the urine. The results were normalized with urinary creatinine (Cr).

During the first 6 months, from 6 to 12 months, and in the second year of life, median SFU hydronephrosis grade and uEGF levels were 2, 2 (p = 0.015), and 1 (p < 0.01), and 50, 59 (p = 0.015), and 69.5 ng/mg Cr (p < 0.01), respectively, in the observational group. In the first 6 months, preoperatively and at 3–12 months postoperatively, the median SFU hydronephrosis grade and uEGF levels were 4, 4, and 3 (p > 0.05), and 38, 46, (p > 0.05), and 55 ng/mg Cr (p < 0.01), respectively, in the surgical group. uEGF levels in the first 6 months of life were significantly lower in the surgical group than in the observational group (p < 0.01). Patients in the observational group with SFU grade 3–4 hydronephrosis showed higher uEGF levels than those in the surgical group with SFU grade 3–4 in (p = 0.048).

Urinary EGF changes over time are associated with inverse changes in SFU hydronephrosis grade, which suggests a role for uEGF as a predictive marker of worsening hydronephrosis grades in infants with ANH. uEGF in the first 6 months of life may predict the need for surgery in infants with ANH.