Serum and urinary procollagen III aminoterminal propeptide as a biomarker of obstructive nephropathy in children.

BACKGROUND

Ureteropelvic junction obstruction (UPJO) is the most common cause of chronic renal failure in children. Rapid diagnosis is important to preserve function and/or to slow down renal injury. This study was to examine serum and urinary procollagen III aminoterminal propeptide (sPIIINP/uPIIINP) protein as potential biomarkers of obstruction in hydronephrosis.

METHODS

The study included 29 children with unilateral UPJO who underwent pyeloplasty (Group 1), 30 children with mild, nonobstructive hydronephrosis (Group 2), and 30 healthy children. In Group 1, serum and voided urine samples were obtained at preoperative, 3 days, and 3, 6 and 12 months after pyeloplasty, respectively. Meanwhile, additional urine from the affected pelvis was collected at surgery. Serum and voided urine were evaluated for PIIINP in each group using immunoenzymatic enzyme-linked immunosorbent assay (ELISA) commercial kits and were expressed in picograms per milligram creatine (cr.).

RESULTS

The preoperative sPIIINP and uPIIINP levels were significantly greater in Group 1 than in other 2 groups. Three months after pyeloplasty, sPIIINP and uPIIINP levels had decreased significantly in Group 1 together with significant improvement of split renal function. Receiver operator characteristic (ROC) analyses revealed a good diagnostic profile for uPIIINP/cr. in identifying children with abnormal split renal function (<40%) [area under the curve (AUC) 0.789].

CONCLUSIONS

Increasing uPIIINP levels are associated with worsening obstruction. Additional studies are required to confirm a potential application uPIIINP as a useful biomarker for the diagnosis and progression of congenital obstructive nephropathy.