Paediatric nephrology (original) (raw)

2012, Nephrology Dialysis Transplantation

Introduction and Aims: Congenital obstructive nephropathy is the primary cause of chronic renal failure in children. Rapid diagnosis and initiation of the treatment are vital to preserve function and/or to slow down renal injury. In oxidative stress, heme oxygenase-1 (HO-1) plays a pivotal role in maintaining renal function and protecting renal structure, especially in renal tubular epithelial cells. The aim of our study was to determine whether urinary (u) HO-1 may be a useful biomarker in children with congenital hydronephrosis (HN) caused by ureteropelvic junction obstruction. Methods: The study consisted of 25 children with severe HN who required pyeloplasty (average age: 2.37 ± 0.66 years), 25 children with mild, non-obstructive HN (average age: 7.13 ± 0.65 years) and 30 healthy children (control group, average age: 5.95 ± 0.70 years). Immunoenzymatic ELISA commercial kits were used to measure uHO-1 concentration. Results: The uHO-1 and uHO-1/creatinine (cr) levels before surgery and during surgery were significantly greater in children with severe HN than in both children with mild, non-obstructive HN and control group (P < 0.01). Three months after surgery, uHO-1/cr decreased significantly in children with severe HN compared with that before surgery (1.73 ± 0.25 ng/mg vs. 4.23 ± 0.53 ng/mg; P < 0.01), but was still higher than that in children with mild, non-obstructive HN (1.73 ± 0.25 ng/mg vs. 1.04 ± 0.21 ng/mg; P < 0.05). The uHO-1 and uHO-1/creatinine (cr) levels were markedly lower in control group than that in children with mild, non-obstructive HN (uHO-1: 0.36 ± 0.06 ng/mg vs. 0.84 ± 0.11 ng/mg, P < 0.01; uHO-1/cr: 0.56 ± 0.10 ng/mg vs. 1.04 ± 0.21 ng/mg, P < 0.05). Moreover, a negative correlation between uHO-1/cr ratio and split renal function was found before surgery (r = −0.593, P = 0.002) and during pyeloplasty (r = −0.452, P = 0.023) in children with severe HN. Receiver operator characteristic analysis revealed that a good diagnostic profile for uHO-1 in terms of identifying a split renal function of < 40% in HN patients (area under the curve (AUC) 0.767) and < 45% in all examined children (AUC 0.812). Conclusions: These results indicate that increasing uHO-1 level is associated with worsening obstruction and uHO-1 is a potential useful, novel, and noninvasive biomarker for evaluating the progression of obstructive nephropathy.