Taha MA et al. (2007) Diagnosis of ureteropelvic junction obstruction in children: role of endothelin-1 in voided urine. Urology 69: 560–564

Researchers in Egypt have shown that the level of endothelin-1 (ET-1) in voided urine provides a useful marker for ureteropelvic junction obstruction (UPJO), and could be used as a noninvasive tool for the diagnosis and long-term follow-up of children with this condition.

UPJO in children is usually diagnosed using radiologic investigations, with the major disadvantage of exposing the child to radiation, so the noninvasive nature of urinary biomarkers makes them an attractive alternative.

Taha and colleagues prospectively compared ET-1 levels in the urine of 35 children with unilateral UPJO with the corresponding levels in a control group of 30 children (10 with vesicoureteral reflux, 10 with renal stones, and 10 healthy children). Urine samples were taken from the children with UPJO before undergoing pyeloplasty, during surgery, and at 1, 2, 3, 6, 9, and 12 months postoperatively.

The preoperative ET-1 level in the urine of children with UPJO was nearly fourfold higher than those in the control groups. Using a cutoff value of 3 fmol/mg creatinine, ET-1 had a diagnostic accuracy of 81.5%, a sensitivity of 74.3%, and a specificity of 90%. In children aged ≤1 year (n = 8), the sensitivity and specificity were 100% using a cutoff value of 4 fmol/mg creatinine. In the patients with UPJO, ET-1 levels had decreased significantly 12 months after pyeloplasty, compared with the corresponding preoperative values.