First-year profile of biomarkers for early detection of renal injury in infants with congenital urinary tract obstruction.

BACKGROUND: Diagnosis of renal function impairment and deterioration in congenital urinary tract obstruction (UTO) continues to be extremely challenging. Use of renal biomarkers in this setting may favor early renal injury detection, allowing for a reliable choice of optimal therapeutic options and prevention or minimization of definitive renal damage. METHODS: This longitudinal, prospective study analyzed the first-year profile of two serum renal biomarkers: creatinine (sCr) and cystatin C (sCyC); and six urinary renal biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), transforming growth factor beta-1 (TGF-ß1), retinol-binding protein (RBP), cystatin C (uCyC), and microalbuminuria (µALB) in a cohort of 37 infants with UTO divided into three subgroups: 14/37 with unilateral hydro(uretero)nephrosis, 13/37 with bilateral hydro(uretero)nephrosis, and 10/37 patients with lower urinary tract obstruction (LUTO), compared with 24 healthy infants matched by gestational age and birth weight. RESULTS: All urine biomarkers showed significantly higher values at the first month of life (p ≤ 0.009), while NGAL (p = 0.005), TGF-ß1 (p < 0.001), and µALB (p < 0.001) were high since birth compared to controls. Best single biomarker performances were RBP in bilateral hydronephrosis and LUTO subgroups and KIM-1 in unilateral hydronephrosis subgroup. Best biomarker combination results for all subgroups were obtained by matching RBP with TGF-ß1 or KIM-1 and NGAL with CyC ([AUC] ≤ 0.934; sensitivity ≤ 92.4%; specificity ≤ 92.8%). CONCLUSIONS: RBP, NGAL, KIM-1, TGF-ß1, and CyC, alone and especially in combination, are relatively efficient in identifying surgically amenable congenital UTO and could be of practical use in indicating on-time surgery.

Rare copy number variants implicated in posterior urethral valves.

The cause of posterior urethral valves (PUV) is unknown, but genetic factors are suspected given their familial occurrence. We examined cases of isolated PUV to identify novel copy number variants (CNVs). We identified 56 cases of isolated PUV from all live-births in New York State (1998-2005). Samples were genotyped using Illumina HumanOmni2.5 microarrays. Autosomal and sex-linked CNVs were identified using PennCNV and cnvPartition software. CNVs were prioritized for follow-up if they were absent from in-house controls, contained ≥ 10 consecutive probes, were ≥ 20 Kb in size, had ≤ 20% overlap with variants detected in other birth defect phenotypes screened in our lab, and were rare in population reference controls. We identified 47 rare candidate PUV-associated CNVs in 32 cases; one case had a 3.9 Mb deletion encompassing BMP7. Mutations in BMP7 have been associated with severe anomalies in the mouse urethra. Other interesting CNVs, each detected in a single PUV case included: a deletion of PIK3R3 and TSPAN1, duplication/triplication in FGF12, duplication of FAT1--a gene essential for normal growth and development, a large deletion (>2 Mb) on chromosome 17q that involves TBX2 and TBX4, and large duplications (>1 Mb) on chromosomes 3q and 6q. Our finding of previously unreported novel CNVs in PUV suggests that genetic factors may play a larger role than previously understood. Our data show a potential role of CNVs in up to 57% of cases examined. Investigation of genes in these CNVs may provide further insights into genetic variants that contribute to PUV.

Is Vesicostomy Still a Contemporary Method of Managing Posterior Urethral Valves?

In boys with posterior urethral valves (PUVs) the main treatment aim is to preserve long-term bladder and renal function. To determine the effectiveness of secondary vesicostomy in boys with PUVs, the medical records of 21 patients with PUV (2010-2019), divided into two groups (group I: valve ablation; group II: secondary vesicostomy), were reviewed regarding the course of serum creatinine, renal ultrasound, voiding cystourethrogram, urodynamics, postoperative complications, need of further surgery, and long-term solution. The median age of all patients at first follow-up was 11 (9-13) months and at last follow-up 64.5 (39.5-102.5) months. Despite a significant difference of the SWDR score (shape, wall, reflux, and diverticula) (p = 0.014), both groups showed no significant differences preoperatively. Postoperatively, serum creatinine (p = 0.024), grade of vesicoureteral reflux (p = 0.003), side of upper tract dilatation (p = 0.006), side of megaureter (p = 0.004), and SWDR score (p = 0.002) were significantly decreased in group II. Postoperative urodynamic measurements showed comparable results in both groups. Stoma complications were found in three (20%) patients (group II). Eight (53.3%) patients already received a closure of the vesicostomy. Seven out of eight (87.5%) patients were able to micturate spontaneously. Vesicostomy remains a reliable treatment option for boys with PUV to improve bladder function and avoid further damage to the urinary tract.

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.

Can bladder fibrosis in congenital urinary tract obstruction be reversed?

A variety of conditions exists in adults and children in which functional or anatomical urinary tract obstructions cause bladder fibrosis, which reduces the bladder's ability to store and empty urine. Current surgical procedures include removal of the obstructions to facilitate bladder emptying or prompt prenatal or postnatal spinal closure to prevent further neurogenic damage. Bladder fibrosis may occur, and it can get worse if a flow hindrance persists or deteriorates. Anti-fibrotic therapeutic strategies that target a variety of factors have been developed in animal models, but currently there are no anti-fibrotic therapies available for clinical use. This review examines the pathogenesis of bladder fibrosis that is caused by congenital obstructions of the lower urinary tract, and it focuses on the principal signalling factors and potential treatment modalities.