The role of renal biomarkers to predict the need of surgery in congenital urinary tract obstruction in infants.

INTRODUCTION: The diagnosis of renal function impairment and deterioration in congenital urinary tract obstruction (UTO) continues to be extremely challenging. The use of new renal biomarkers in this setting may favor early renal injury detection, allowing for a reliable choice of optimal therapeutic options and the prevention or minimization of definitive renal damage. OBJECTIVE: The aim of the study was to investigate a selection of promising biomarkers of renal injury with the intention of evaluating and comparing their profile with clinically based decisions for surgical intervention of infants with congenital obstructive uropathies. STUDY DESIGN: The first-year profile of renal biomarkers, serum creatinine (sCr), serum and urine cystatin C (CyC), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), transforming growth factor beta-1 (TGF-ß1), retinol-binding protein (RBP), and microalbuminuria (µALB), was analyzed in a cohort of 37 infants with congenital UTO, divided into three subgroups, 14 cases with grade III unilateral hydro(uretero)nephrosis, 13 cases with grade III bilateral hydro(uretero)nephrosis, and 10 cases with low urinary tract obstruction (LUTO), compared with 24 healthy infants matched by gestational age and birth weight. Serum and urine samples were stored at -70 °C and thereafter analyzed by quantitative enzymatic immunoassay. RESULTS: Compared with the control group (Figure), all renal biomarker values were significantly increased in patients (P ≤ 0.02). In the unilateral hydronephrosis and LUTO group, RBP (P ≤ 0.043), NGAL (P ≤ 0.043), KIM-1 (P ≤ 0.03), and TGF-ß1 (P ≤ 0.034) values dropped significantly after surgery. Neutrophil gelatinase-associated lipocalin alone and in combination with urine and serum CyC demonstrated the best performance in determining the need for surgery (area under the curve, 0.801 and 0.881, respectively). Biomarker profile analysis was suggestive of surgical intervention in 55.4% (7/13) of non-operated cases, and most of the biomarker values were above the cutoff levels within at least 3 months before the clinically based surgical decision in 58% (14/24) of all operated patients. DISCUSSION: To the best of the authors' knowledge, this is the first study to present the clinical use of selected group of serum and urinary biomarkers in the setting of UTO to distinguish between patients who would benefit from surgery intervention. The most promising results were obtained using NGAL, RBP, TGF-ß1, and KIM-1, especially in the unilateral hydro(uretero)nephrosis and LUTO subgroups when compared with the control group. CONCLUSIONS: Urine biomarkers, alone and in combination, demonstrated high potential as a non-invasive diagnostic tool for identifying infants who may benefit from earlier surgical intervention.

Percutaneous ultrasound-guided renal biopsy in children - safety, efficacy, indications and renal pathology findings: 14-year Brazilian university hospital experience.

INTRODUCTION: Pediatric percutaneous renal biopsy (Bx) is a routine procedure in pediatric nephrology to obtain renal tissues for histological study. We evaluated the safety, efficacy, indications and renal findings of this procedure at a tertiary care pediatric university hospital and compared our findings with the literature. METHODS: Retrospective study based on medical records from January 1993 to June 2006. RESULTS: In the study period, 305 Bx were performed in 262 patients, 127 (48.5%) male, aged 9.8 A+/- 4.2 years. A 16-gauge needle was utilized in 56/305 Bx, an 18-gauge needle in 252/305 Bx (82.6%). 56.1% Bx were performed under sedation plus local anesthesia, 43.9% under general anesthesia. The number of punctures per Bx was 3.1 A+/- 1.3. Minor complications occurred in 8.6% procedures. The 16-gauge needle caused a higher frequency of renal hematomas (p = 0.05). The number of glomeruli per puncture was >or= 5 in 96.7% and >or= 7 in 92%. Glomeruli number per puncture and frequency of complications were not different according to the type of anesthesia used. A renal pathology diagnosis was achieved in 93.1% Bx. The main indications of Bx were nephrotic syndrome (NS), lupus nephritis (LN) and hematuria (HE). The diagnosis of minimal change disease (MCD) (61.3%), class V (35.6%) and IgA nephropathy (26.3%) predominated in NS, LN and HE patients, respectively. CONCLUSION: Pediatric real-time ultrasound-guided percutaneous renal biopsy was safe and effective. The main clinical indications for Bx were NS and LN, the predominant renal pathology diagnoses were MCD and class V LN.