Elsevier

Urology

Volume 73, Issue 5, May 2009, Pages 1016-1020
Urology

Pediatric Urology
Role of Urinary Tubular Enzymes in Evaluation of Children With Ureteropelvic Junction Narrowing Under Conservative Management

https://doi.org/10.1016/j.urology.2008.12.038Get rights and content

Objectives

To evaluate the role of urinary lysosomal enzyme N-acetyl-β-D-glucosaminidase (NAG) and brush border enzymes alkaline phosphatase (ALP) and γ-glutamyl transferase (GGT) in the long-term follow-up of children under conservative management for ureteropelvic junction narrowing.

Methods

The study included 30 children with dilated nonobstructed kidneys due to unilateral ureteropelvic junction narrowing who were treated conservatively and followed up for 15 months. Voided urine samples were obtained from the children at diagnosis and at 3, 9, and 15 months of follow-up. NAG, ALP, and GGT were measured in these urine samples.

Results

The conservative management of the children during their follow-up period revealed stabilization of renal function in 15 patients (dilated nonobstructed group) and deterioration in 15 (obstructed group). In patients considered to have dilated nonobstructed kidneys, a comparison between the mean values of urinary NAG, ALP, and GGT at the last follow-up and at baseline showed no significant differences. In addition, the mean values of glomerular filtration rate and split renal function showed no significant changes at the last follow-up examination compared with the basal condition. In patients considered to have obstructed kidneys, a comparison between the mean values of the 3 enzymes at diagnosis and at basal condition showed a significant increase in the 3 urinary biomarkers. Moreover, the mean values of the glomerular filtration rate and split renal function showed a significant reduction at diagnosis compared with the basal condition.

Conclusions

NAG, ALP, and GGT are noninvasive biomarkers that could be used for long-term follow-up of children with ureteropelvic junction narrowing under conservative management to determine those who might develop obstruction.

Section snippets

Material and Methods

The study group included 30 children (22 boys and 8 girls) with a diagnosis of unilateral UPJ narrowing. Their mean age ± SEM was 5 ± 0.68 years (range 9 months to 12 years). All patients were diagnosed as having unilateral dilated nonobstructed kidneys due to UPJ narrowing as documented by nonobstructed washout renographic curve and a half-time drainage of <10 minutes with split renal function >40% on diuretic renography.5 Moreover, the children had no symptoms or signs suggestive of renal

Results

The consecutive evaluation of GFR and split renal function of the corresponding kidneys during conservative management revealed stabilization in 15 patients (50%) and deterioration in 15 patients (50%). The deterioration of renal function was observed at 3 months in 5 patients, 9 months in 7, and 15 months in 3 patients. All patients with renal deterioration were considered obstructed and immediately underwent pyeloplasty. The 15 patients with stabilization of renal function were considered to

Comment

The major clinical challenges of evaluating and treating patients with obstructive nephropathy relate to the indications for, and timing of, surgical intervention and establishing prognostic indicators for progression.12 The identification of suitable biomarkers of renal injury resulting from urinary tract obstruction would be useful in tracking the progression of the disorder and in monitoring the response to new therapies.13

Urinary enzymes originate in the kidneys, and many of them can be

Conclusions

The renal tubular enzymes NAG, ALP and GGT are noninvasive biomarkers that could be used in the long-term follow-up of children with UPJ narrowing under conservative management to identify those children who might develop obstruction and need surgical correction.

Cited by (0)

View full text