Urinary Excretion of Various Urinary Proteins in Children with Vesicoureteral Reflux

Jung, Da Eun; Koo, Ja Wook

Abstract

PURPOSE
This study aimed to examine the excretion of various urinary proteins in children with a history of urinary tract infection(UTI), with or without vesicoureteral reflux(VUR) or reflux nephropathy, and to identify means of predicting the severity of VUR or the presence of reflux nephropathy as indicated by these markers, and to know how these markers are changed after resolution of VUR.
METHODS
We studied 30 children with previous UTI, without VUR and renal scarring(group I), 12 children with VUR, without evidence of renal scarring(group II), and 34 children with VUR and renal scarring(group III). 24-hour or 12-hour urine beta2 microglobulin(beta2 MG), microalbumin and N- acetyl-beta-D-glucosaminidase(NAG) were measured in each child. Urinary protein excretions were analyzed according to the degree of VUR(mild VUR : a grade reflux I-III, severe VUR : a grade reflux IV-V). Cases of bilateral VUR were graded by the higher grade of reflux detected. A total of 46 children with primary VUR were followed. Among these patients, VUR was completely resolved in 16 children. Voiding cystourethrography(VCUG) and DMSA scan were performed every year. Values for urinary markers were estimated every year.
RESULTS
24 or 12 hour urine microalbumin and NAG excretions were significantly increased in group III compared to group I(microalbumin : 27.7+/-26.0 mg/gCr vs 15.0+/-10.7 mg/gCr, P<0.05, NAG : 15.2+/-18.7 U/gCr vs 3.4+/-2.2 U/gCr, P<0.05). Urinary beta2 MG excretions were not significantly different between groups. Urinary NAG excretions were elevated in the group of children with severe VUR compared to mild VUR(26.8+/-27.1 U/gCr vs 7.6+/-3.8 U/gCr, P<0.05). After resolution of VUR, urinary microalbumin and NAG excretions were decreased(P<0.05).
CONCLUSION
Urinary microalbumin and NAG may be useful clinical indicators to predict the presence of reflux nephropathy and the resolution of VUR. Especially, urinary NAG excretions may be used as a possible method to predict the severity of VUR.