Survival and Kidney Outcomes of Children with an Early Diagnosis of Posterior Urethral Valves

Posterior urethral valves: Clinical audits of presentation, diagnostic and therapeutic intervention in a nigerian teaching hospital

PURPOSE

We described our experience in the management of PUV at UNIOSUN Teaching Hospital, Osogbo, Osun State.

METHODS

This was a retrospective analysis of patients with diagnosis of PUV carried out over a 4 year period (2019-2023). Demographic characteristics, clinical presentation, diagnosis and mode of therapeutic interventions were the variables analysed.

RESULTS

A total of 17 patients with PUV were managed during the study period. Median age at presentation and surgery were 10 months (range 3.0-48.0) and 13 months (range 3.0-49.5), respectively. Most common presentation was poor urinary stream, 11 (64.7%). Mean PCV was 34.42%. Klebsiella aerogens was the predominant 9 (52.9%) organism isolated. A patient had prenatal USS diagnosis suggestive of PUV, majority (52.9%) had bilateral grade 1 V hydronephrosis at presentation. Voiding cystogram was diagnostic in 14 patients, (82.4%) while urethrocystoscopy was done in 14 (82.4%) patients. Median creatinine level were 116, 76.5 and 51.0 (micromol/l) pre- and post-catheterization and 1 month post-surgery, respectively. There was positive correlation between the age and post- surgery creatinine but a negative correlation between the PCV and grade of hydronephrosis. All patients had Mohans valvotomy. We had mortality in a patient from urosepsis. At 6 months-1 year follow-up, 15 patients had good urine stream with stable renal function.

CONCLUSION

Early intervention assist in optimizing renal and bladder function and minimize risk of urosepsis. Where there is no facility for endoscopic valve ablation, Mohans valvotomy remains a viable treatment option.

Long-Term Kidney Outcomes in Children with Posterior Urethral Valves: A Population-Based Cohort Study

Key Points

Background

Posterior urethral valves represent the most common cause of lower urinary tract obstruction in male infants (approximately 1/4000 live births). Long-term kidney outcomes of posterior urethral valves remain uncertain. We aimed to determine the time-varying risk of major adverse kidney events (MAKE) following children with posterior urethral valves into adulthood.

Methods

A population-based retrospective cohort study of all male children (<2 years) diagnosed with posterior urethral valves between 1991 and 2021 in Ontario, Canada. Comparator cohorts were (1) male general population and (2) male children with pyeloplasty (both <2 years). The primary outcome was MAKE (death, long-term KRT [dialysis or kidney transplant], or CKD). Time to MAKE was analyzed using multivariable-adjusted Cox proportional hazards models. We censored for provincial emigration or administrative censoring (March 31, 2022).

Results

We included 727 children with posterior urethral valves, 855 pyeloplasty comparators, and 1,013,052 general population comparators. The median follow-up time was 16.6 years (Q1–3, 8.6–24.5) overall. Throughout follow-up, 32% of children with posterior urethral valves developed MAKE versus 1% of the general population and 6% of pyeloplasty comparators. Their adjusted hazard ratio for MAKE was 36.6 (95% confidence interval, 31.6 to 42.4) versus the general population. The risk of developing MAKE declined over the first 5 years after posterior urethral valves diagnosis but remained elevated for >30-year follow-up. Children with posterior urethral valves were also at higher risk of death, CKD, long-term KRT, hypertension, and AKI than the general population or pyeloplasty comparators.

Conclusions

Children with posterior urethral valves are at higher risk of adverse long-term kidney outcomes well into adulthood.

Simultaneous primary posterior urethral valves ablation and bladder neck incision may decrease kidney and bladder failure in long-term follow-up in patients with bladder neck hypertrophy and poor bladder function at presentation: report of 301 cases

OBJECTIVES

To investigate the effects of bladder neck incision (BNI) and primary valves ablation on long-term kidney and bladder function in children with posterior urethral valves (PUV) and bladder neck hypertrophy (BNH).

PATIENTS AND METHODS

From 1997 to 2016, a total of 1381 children with PUV were referred to our tertiary hospital. Of these patients, 301 PUV patients with bladder neck hypertrophy need concurrent BNI and valve ablation. All patients were followed up every 3-6 months on regular basis in first 2 post-surgical years and annually then after. The paired t-test and chi-square test were used to perform statistical analysis with p value < 0.05 defined as the level of significance.

RESULTS

Mean age at diagnosis was 7.22 ± 2.45 months (ranging from 7 days to 15 months) with a mean follow-up of 5.12 ± 2.80 years. The incidence of hydronephrosis was decreased from 266 (88.3%) at the baseline to 73 (24.3%) patients in long-term follow-up. At baseline, 188 (62.5%) patients were diagnosed with VUR, which decreased to 20 (6.6%) individuals at the end of follow-up. Bladder and renal function were improved in follow-ups following concomitant PUV ablation and BNI. No Myogenic failure was depicted in all patients with BNH. No ureteric reimplantation was needed during the two decades follow-up.

CONCLUSION

Simultaneous valve ablation with BNI may present further profits in children with PUV and BNH particularly cases of BNH with poor bladder function at the time of presentation. This method can improve the results of urodynamic and imaging studies after the surgery. We hypothesize every child with PUV presentation who has concurrent vesicoureteral reflux, CKD or persistent hydrourethronephrosis may suffer from secondary bladder neck obstruction. This secondary bladder outlet obstruction must be managed through BNI as the surgical relief.

Clinical considerations in adults with history of posterior urethral valves

INTRODUCTION

Management of patients with posterior urethral valves (PUV) is commonplace for many pediatric urologists, however adult providers may be far less familiar with this diagnosis, its management and long-term ramifications. As urologic management of these patients has evolved, clinical outcomes have substantially improved with many more patients now surviving into adulthood. These patients remain at increased risk of morbidity due to their condition and therefore are likely to benefit from long term follow-up with adult providers.

OBJECTIVE

In this review we analyze the psychosocial impacts of PUV on adults, evaluate long term transplant outcomes in PUV patients and discuss effective clinical management strategies of bladder dysfunction in adult PUV patients.

STUDY DESIGN

A retrospective literature review was performed using the MEDLINE (Pubmed) electronic database using key words such as "posterior urethral valve", "quality of life", "sexual function", "transplant outcomes", "bladder dysfunction", "mitrofanoff" etc. to identify relevant studies.

RESULTS

Generally, the quality of life of PUV patients is good, those suffering from renal insufficiency or lower urinary tract symptoms, specifically incontinence, appear to be a group that may benefit from more intensive follow-up. Good long-term kidney transplant (KT) function and survival can be achieved in patients with PUV. Rigorous management to optimize bladder function and close follow-up, are key for long term graft survival after KT.

DISCUSSION

The chronicity of PUV warrants adult providers to be not only well versed in the pathophysiology of the disease, but well prepared to care for these patients as they transition into adulthood.

CONCLUSION

Additional studies addressing psychosocial, clinical and transplant outcomes of adults with PUV are necessary to develop optimal long-term follow-up regimens for these patients.

Trends in Management of Fetuses with Suspected Lower Urinary Tract Obstruction (LUTO): A High-Risk Fetal and Pediatric Center Experience in a Universal-Access-to-Care System

INTRODUCTION

 Neonates with lower urinary tract obstruction (LUTO) experience high morbidity and mortality associated with the development of chronic kidney disease. The prenatal detection rate for LUTO is less than 50%, with late or missed diagnosis leading to delayed management and long-term sequelae in the remainder. We aimed to explore the trends in prenatal detection and management at a high-risk fetal center and determine if similar trends of postnatal presentations were noted for the same period.

METHODS

 Prenatal and postnatal LUTO databases from a tertiary fetal center and its associated pediatric center between 2009 and 2021 were reviewed, capturing maternal age, gestational age (GA) at diagnosis, and rates of termination of pregnancy (TOP). Time series analysis using autocorrelation was performed to investigate time trend changes for prenatally suspected and postnatally confirmed LUTO cases.

RESULTS

 A total of 161 fetuses with prenatally suspected LUTO were identified, including 78 terminations. No significant time trend was found when evaluating the correlation between time periods, prenatal suspicion, and postnatal confirmation of LUTO cases (Durbin-Watson [DW] = 1.99, p = 0.3641 and DW = 2.86, p = 0.9113, respectively). GA at referral was 20.0 weeks (interquartile range [IQR] 12, 35) and 22.0 weeks (IQR 13, 37) for TOP and continued pregnancies (p < 0.0001). GA at initial ultrasound was earlier in terminated fetuses compared to continued (20.0 [IQR 12, 35] weeks vs. 22.5 [IQR 13, 39] weeks, p < 0.0001). While prenatal LUTO suspicion remained consistently higher than postnatal presentations, the rates of postnatal presentations and terminations remained stable during the study years (p = 0.7913 and 0.2338), as were GA at TOP and maternal age at diagnosis (p = 0.1710 and 0.1921).

CONCLUSION

 This study demonstrated that more severe cases of LUTO are referred earlier and are more likely to undergo TOP. No significant trend was detected between time and prenatally suspected or postnatally confirmed LUTO, highlighting the need for further studies to better delineate factors that can increase prenatal detection.

Mechanical Ablation of the Posterior Urethral Valve Omitting Thermal Energy: A Brief Report

Management of the posterior urethral valve (PUV) is a clinical challenge in pediatric urology. We report the results of a modified valve ablation method without using a pediatric resectoscope and thermal energy. Patients were selected from children with PUV who were referred to the pediatric urology clinic of Shahid Labbafinejad Hospital, Tehran, Iran, and have undergone endoscopic valve ablation surgery between May 2019 to May 2021. Ten male patients with PUV underwent mechanical valve ablation without the use of the conventional pediatric resectoscope, and thermal energy was replaced by a 6F semi-rigid urethroscope and 3Fr ureteral catheter. Patients were assessed both pre-and postoperatively using serum creatinine, urinary tract ultrasound imaging, and voiding cystourethrography. The mean age was 23.88±30.13 months (range= 25 days to 8 years). Four out of 10 patients (40%) had elevated serum creatinine, and seven had unilateral or bilateral hydroureteronephrosis (70%). No major complications were reported according to Clavien-Dindo Classification System. The level of serum creatinine, the grade of hydroureteronephrosis, and the ratio of the prostatic urethra to anterior urethra diameter in postoperative voiding cystourethrography were decreased. A decrease in serum creatinine level occurred in patients after valve ablation, but this decrease was not statistically significant (P=0.059). The decrease in hydroureteronephrosis grade on the right (P=0.006) and left (P=0.022) was statistically significant. There was no evidence of urethral stenosis or need for repeating resection. It can be concluded that our mechanical valve ablation method might be a safe and effective technique for PUV ablation.

Survival of neonates born with kidney failure during the initial hospitalization

BACKGROUND

Survival to hospital discharge in neonates born with kidney failure has not been previously described.

METHODS

This was a retrospective, observational analysis of the Pediatric Health Information System (PHIS) database from 2005 to 2019. Primary outcome was survival at discharge; secondary outcomes were hospital and ICU length of stay (LOS). Univariate analysis was performed to describe the population by birth weight (BW) and characterize survival; multivariable generalized liner mixed modeling assuming a binomial distribution and logit link was performed to identify mortality risk factors.

RESULTS

Of 213 neonates born with kidney failure (median BW 2714 g; GA 35 weeks; 68% male), 4 (1.9%) did not receive dialysis or peritoneal dialysis (PD) catheter placement, 152 (72.9%) received PD only, 49 (23.4%) received PD plus extracorporeal dialysis (ECD), and 8 (3.4%) were treated with an undocumented dialysis modality. Median age at dialysis initiation was 7 days; median hospital LOS and ICU LOS were 84 and 69 days, respectively. One-hundred and sixty-two patients (76%) survived to discharge. Non-survivors (n = 51) were more likely to have received ECD and mechanical ventilation, and had a longer duration of mechanical ventilation. Every day of mechanical ventilation increased the mortality odds by 2% (n = 189; adjusted OR 1.02; 1.01, 1.03); in addition, the odds of mortality were 2 times higher in those who received ECD vs. only PD (adjusted OR 2.25; 1.04, 4.86).

CONCLUSIONS

Survival to initial hospital discharge occurs in the majority of neonates born with kidney failure. Predictors of increased mortality included longer duration of mechanical ventilation, as well as the requirement for ECD. A higher resolution version of the Graphical abstract is available as Supplementary information.

HucMSC exosomes attenuate partial bladder outlet obstruction-induced renal injury and cell proliferation via the Wnt/β-catenin pathway

Bladder outlet obstruction (BOO) can cause serious complications including kidney damage; nevertheless, there are currently no animal models for studying BOO-induced kidney damage. Mesenchymal stem cells (MSCs) are widely used in therapeutic studies of renal fibrosis. However, MSC-derived exosomes show improved safety profile and more controllable characteristics compared with those of MSCs. Herein, we established a kidney injury mouse model of partial bladder outlet obstruction (PBOO) and evaluated the effects of human umbilical cord MSC-derived exosomes (hucMSC-Exos) on PBOO-induced reflux kidney injury in this model. Exosomes were isolated from a hucMSC-conditioned medium, purified by ultracentrifugation, and examined. Living image was performed to indicate the distribution of hucMSC-Exos. The PBOO-treated mice interacted with PBS (phosphate-buffered saline) or hucMSC-Exos. Morphologic changes and expression of interstitial-fibrosis-related, cell proliferation and Wnt/β-catenin signaling-pathway indices were evaluated. At 7 days after induction of PBOO, structural destruction of renal tubules was observed. Expression of the interstitial markers and the cellular-proliferation index increased significantly in the PBOO group compared with the control group (p < 0.05). The isolated exosomes were 30-150 nm in diameter, showing a round shape and bilayer membrane structure with CD63, TSG101, Alix expressed, enriched in the kidney of the PBOO group. Administering hucMSC-Exos to post-PBOO mice reversed renal injury and suppressed expression of Wnt/β-catenin signaling pathway-related proteins. hucMSC-Exos inhibited PBOO-induced kidney injury and cellular proliferation and suppressed the Wnt/β-catenin signaling pathway. Our findings will spur the development of novel hucMSC-Exo-mediated therapies for treating patients with renal fibrosis.

Predictive factors for survival in patients with oligohydramnios secondary to antenatal kidney disease

BACKGROUND

Renal oligohydramnios (ROH) is caused by bilateral congenital abnormalities, either of renal parenchymal or obstructive origin. ROH is a poor prognostic factor of neonatal survival; lung hypoplasia is reported to be the main cause of mortality. We aimed to describe the fetal morbidity and pre- and postnatal mortality in case of ROH due to renal congenital pathologies and to find predictive risk factors for morbidity and mortality.

METHODS

All data were collected in Trousseau Hospital in the obstetric, neonatology, and pediatric nephrology units, from 2008 to 2020.

RESULTS

We included 66 fetuses with renal parenchymal pathologies posterior urethral valves (PUV) (N = 25), bilateral kidney agenesis (N = 10), hypodysplasia (N = 16), and polycystic kidney disease (N = 10) causing oligohydramnios identified on antenatal ultrasound. Total pre- and postnatal mortality was 76% (50/66). Mortality, excepting termination of pregnancy (TOP), was 65%. The presence of pneumomediastinum and pneumothorax was not different in survivors and non-survivors. Fetuses with kidneys having features of hypodysplasia on ultrasound at T2 and those with oligohydramnios before 32 weeks GA had a higher risk of death. There was a significant difference in plasma creatinine of the surviving patients compared to the deceased patients, from day 3 onwards (183 µmol/L [88; 255] vs. 295 µmol/L [247; 326]; p = 0.038).

CONCLUSIONS

The main differences between survivors and non-survivors among patients with "renal oligohydramnios" were oligohydramnios detection before 32 weeks GA, dysplasia detection on the second trimester ultrasound, and increase of serum creatinine from day 3 onwards. A higher resolution version of the Graphical abstract is available as Supplementary information.

Chronic Kidney Disease in Boys with Posterior Urethral Valves-Pathogenesis, Prognosis and Management

Posterior urethral valves (PUV) are the most common form of lower urinary tract obstructions (LUTO). The valves can be surgically corrected postnatally; however, the impairment of kidney and bladder development is irreversible and has lifelong implications. Chronic kidney disease (CKD) and bladder dysfunction are frequent problems. Approximately 20% of PUV patients will reach end-stage kidney disease (ESKD). The subvesical obstruction in PUV leads to muscular hypertrophy and fibrotic remodelling in the bladder, which both impair its function. Kidney development is disturbed and results in dysplasia, hypoplasia, inflammation and renal fibrosis, which are hallmarks of CKD. The prognoses of PUV patients are based on prenatal and postnatal parameters. Prenatal parameters include signs of renal hypodysplasia in the analysis of fetal urine. Postnatally, the most robust predictor of PUV is the nadir serum creatinine after valve ablation. A value that is below 0.4 mg/dl implies a very low risk for ESKD, whereas a value above 0.85 mg/dl indicates a high risk for ESKD. In addition, bladder dysfunction and renal dysplasia point towards an unbeneficial kidney outcome. Experimental urinary markers such as MCP-1 and TGF-β, as well as microalbuminuria, indicate progression to CKD. Until now, prenatal intervention may improve survival but yields no renal benefit. The management of PUV patients includes control of bladder dysfunction and CKD treatment to slow down progression by controlling hypertension, proteinuria and infections. In kidney transplantation, aggressive bladder management is essential to ensure optimal graft survival.

Posterior Urethral Valves Outcomes Prediction (PUVOP): a machine learning tool to predict clinically relevant outcomes in boys with posterior urethral valves

BACKGROUND

Early kidney and anatomic features may be predictive of future progression and need for additional procedures in patients with posterior urethral valve (PUV). The objective of this study was to use machine learning (ML) to predict clinically relevant outcomes in these patients.

METHODS

Patients diagnosed with PUV with kidney function measurements at our institution between 2000 and 2020 were included. Pertinent clinical measures were abstracted, including estimated glomerular filtration rate (eGFR) at each visit, initial vesicoureteral reflux grade, and renal dysplasia at presentation. ML models were developed to predict clinically relevant outcomes: progression in CKD stage, initiation of kidney replacement therapy (KRT), and need for clean-intermittent catheterization (CIC). Model performance was assessed by concordance index (c-index) and the model was externally validated.

RESULTS

A total of 103 patients were included with a median follow-up of 5.7 years. Of these patients, 26 (25%) had CKD progression, 18 (17%) required KRT, and 32 (31%) were prescribed CIC. Additionally, 22 patients were included for external validation. The ML model predicted CKD progression (c-index = 0.77; external C-index = 0.78), KRT (c-index = 0.95; external C-index = 0.89) and indicated CIC (c-index = 0.70; external C-index = 0.64), and all performed better than Cox proportional-hazards regression. The models have been packaged into a simple easy-to-use tool, available at https://share.streamlit.io/jcckwong/puvop/main/app.py CONCLUSION: ML-based approaches for predicting clinically relevant outcomes in PUV are feasible. Further validation is warranted, but this implementable model can act as a decision-making aid. A higher resolution version of the Graphical abstract is available as Supplementary information.

Survival of children with rare structural congenital anomalies: a multi-registry cohort study

BACKGROUND

Congenital anomalies are the leading cause of perinatal, neonatal and infant mortality in developed countries. Large long-term follow-up studies investigating survival beyond the first year of life in children with rare congenital anomalies are costly and sufficiently large standardized cohorts are difficult to obtain due to the rarity of some anomalies. This study aimed to investigate the survival up to 10 years of age of children born with a rare structural congenital anomaly in the period 1995-2014 in Western Europe.

METHODS

Live births from thirteen EUROCAT (European network for the epidemiological surveillance of congenital anomalies) population-based registries were linked to mortality records. Survival for 12,685 live births with one of the 31 investigated rare structural congenital anomalies (CAs) was estimated at 1 week, 4 weeks and 1, 5 and 10 years of age within each registry and combined across Europe using random effects meta-analyses. Differences between registries were evaluated for the eight rare CAs with at least 500 live births.

RESULTS

Amongst the investigated CAs, arhinencephaly/holoprosencephaly had the lowest survival at all ages (58.1%, 95% Confidence Interval (CI): 44.3-76.2% at 1 week; 47.4%, CI: 36.4-61.6% at 1 year; 35.6%, CI: 22.2-56.9% at 10 years). Overall, children with rare CAs of the digestive system had the highest survival (> 95% at 1 week, > 84% at 10 years). Most deaths occurred within the first four weeks of life, resulting in a 10-year survival conditional on surviving 4 weeks of over 95% for 17 out of 31 rare CAs. A moderate variability in survival between participating registries was observed for the eight selected rare CAs.

CONCLUSIONS

Pooling standardised data across 13 European CA registries and the linkage to mortality data enabled reliable survival estimates to be obtained at five ages up to ten years. Such estimates are useful for clinical practice and parental counselling.

Predictors of advanced chronic kidney disease in infancy after definitive vesicoamniotic shunting for congenital lower urinary tract obstruction

BACKGROUND

Severe congenital lower urinary tract obstruction (cLUTO) is associated with poor postnatal outcomes, including chronic and end stage kidney disease, and high mortality. Studies of the impact of fetal intervention through vesicoamniotic shunting are marred by a device malfunction rate of up to 60%. In this study, we delineate the postnatal course and infant kidney function following definitive urinary diversion in utero.

MATERIALS AND METHODS

This is a retrospective, single-center cohort study of 16 male infants who survived the fetal intervention to birth, from 2010 to 2014 at a single center. All had patent shunts in place at birth. Perinatal and biochemical characteristics were collected with patients followed for one year, or until demise, with serial measures of serum creatinine (SCr) and serum cystatin C (CysC).

RESULTS

Of the 16 males, 81% were non-white (38% black, 43% Hispanic). Shunts were placed at a median of 20 weeks (IQR 19,23) gestation, with median fetal bladder volume of 39 cm³ (IQR 9.9,65). All neonates were born preterm [median 34 weeks (IQR 31,35)] and the majority with low birth weight [median 2340 grams (1,895, 2,600)]. 63% required positive pressure ventilation. Advanced chronic kidney disease stage 4-5 at 1 year of age was predicted by neonatal characteristics: peak SCr ≥2 mg/dl, time to peak SCr > 6 days, discharge SCr ≥1.0 mg/dl, CysC ≥2.5 mg/l, urine protein:creatinine ≥4.8 mg/mg, urine microalbumin:creatinine ≥2.2 mg/mg. In infancy, a nadir SCr ≥0.5 mg/dl occurring before 160 days (5.3 months) of age was also predictive of advanced chronic kidney disease stage 4-5 at 1 year. Three patients died in the neonatal period, with 1 receiving kidney replacement therapy (KRT). Three additional patients required KRT before 12 months of age.

CONCLUSIONS

Even with definitive vesicoamniotic shunting for cLUTO, postnatal morbidity and mortality remain high, emphasizing the role of renal dysplasia, in spite of urinary diversion, in postnatal kidney dysfunction. Neonatal and infant biochemical parameters exhibit distinct trends that offer families and physicians a better understanding of the prognosis of childhood kidney function.

Outcome of Urinary Bladder Dysfunction in Children

Bladder dysfunction in children is common, the most frequent underlying causes are neurologic bladder (NB), dysfunctional voiding syndrome (DVS), and the valve bladder syndrome (VBS). The aim of this study was to determine the 10-y survival rate and the associated morbidities in children with bladder dysfunction. One hundred ninety-nine children were included in the study; 60 with VBS, 75 DVS, and 64 NB. The mean age was 44 mo (CI: 37-50.9) and mean GFR 50.1 (CI 44.6-55.6) mL/min/1.73m². The 10-y survival rate was 89%. Compared with patients with VBS, the mortality was 11 times higher among patients with NB (p = 0.02) but not significantly higher than patients with DVS (p = 0.2). GFR < 15 mL/min/1.73 m² increases mortality rate by 6 times compared with normal GFR (p = 0.007). Late age at presentation (> 5 y) increases mortality risk and/or the need for renal replacement therapy (RRT) by almost 5 times (p = 0.013). It was concluded that the etiology of bladder dysfunction, baseline GFR, and the age at presentation significantly influence the survival rate and morbidities.

Posterior urethral valves: Role of prenatal diagnosis and long-term management of bladder function; a single center point of view and review of literature

Posterior Urethral Valves (PUV) are the most common cause of lower urinary tract obstruction. More severe forms are detected early in pregnancy (mainly type I), while other forms are usually discovered later in childhood when investigating lower urinary tract symptoms. Bladder dysfunction is common and is associated with urinary incontinence in about 55% (0%-72%). Despite the removal of the obstruction by urethral valve ablation, pathological changes of the urinary tract can occur with progressive bladder dysfunction, which can cause deterioration of the upper urinary tract as well. For this reason, all children with PUV require long-term follow-up, always until puberty, and in many cases life-long. Therefore, management of PUV is not only limited to obstruction relief, but prevention and treatment of bladder dysfunction, based on urodynamic observations, is paramount. During time, urodynamic patterns may change from detrusor overactivity to decreased compliance/small capacity bladder, to myogenic failure (valve bladder). In the past, an aggressive surgical approach was performed in all patients, and valve resection was considered an emergency procedure. With the development of fetal surgery, vesico-amniotic shunting has been performed as well. Due to improvements of prenatal ultrasound, the presence of PUV is usually already suspected during pregnancy, and subsequent treatment should be performed in high-volume centers, with a multidisciplinary, more conservative approach. This is considered to be more effective and safer. Primary valve ablation is performed after clinical stability and is no longer considered an emergency procedure after birth. During childhood, a multidisciplinary approach (pediatric urologist, nephrologist, urotherapist) is recommended as well in all patients, to improve toilet training, using an advanced urotherapy program with medical treatments and urodynamic evaluations. The aim of this paper is to present our single center experience over 30 years.

[Establishment of an Animal Model of Vesicoureteral Reflux Renal Injury through Partial Bladder Outlet Obstruction]

OBJECTIVE

To establish an animal model of reflux renal damage through bladder outlet obstruction.

METHODS

Sixty male C57BL/6 mice aged 6-8 weeks were randomly assigned to a control group, a sham operation group, and a partial bladder outlet obstruction (PBOO) group, with 20 mice in each group. Laparotomy were performed on the PBOO mice under anesthesia in order to separate the bladder necks and to perform guided partial ligation of the bladder neck with a metal rod of 0.3 mm diameter. Mice in the sham operation group had laparotomy and had their bladder necks separated without ligation. The control group did not receive any treatment. 7 days after the surgery, 12 surviving mice were randomly selected from each group to observe the general changes of the bladder, ureter, renal pelvis and kidney. Retrograde urography was performed through the bladder. Kidney tissues were extracted for histopathological analysis. The expression levels of Vimentin, proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were examined with Western blot, immunohistochemistry and immunofluorescence staining tests, respectively.

RESULTS

Compared with the control and sham operation group, the bladder, ureter, and renal pelvis of the mice in the PBOO group were significantly enlarged, vesicoureteral reflux was more obvious, the kidney volume and mass increased ( P<0.001), and renal parenchyma became thinner ( P<0.000 1). Histopathological staining showed glomerular atrophy, renal tubule expansion, tubulointerstitial inflammatory cell infiltration, glomerular basement membrane hyperplasia and obvious interstitial fibrosis. Western blot, immunofluorescence and immunohistochemistry staining showed that the expression levels of Vimentin, PCNA and α-SMA in kidney tissue were elevated ( P<0.000 1).

CONCLUSION

After PBOO, the bladder, ureter, and kidney of the mice showed obvious morphological alteration and presented reflux renal fibrosis-like damage. This can be used as an animal model to study the pathological alteration mechanism and therapeutic measures of renal fibrosis caused by bladder outlet obstruction.

Sex effects in pyelonephritis

Urinary tract infections (UTIs) are generally considered a disease of women. However, UTIs affect females throughout the lifespan, and certain male populations (including infants and elderly men) are also susceptible. Epidemiologically, pyelonephritis is more common in women but carries increased morbidity when it does occur in men. Among children, high-grade vesicoureteral reflux is a primary risk factor for upper-tract UTI in both sexes. However, among young infants with UTI, girls are outnumbered by boys; risk factors include posterior urethral valves and lack of circumcision. Recent advances in mouse models of UTI reveal sex differences in innate responses to UTI, which vary somewhat depending on the system used. Moreover, male mice and androgenized female mice suffer worse outcomes in experimental pyelonephritis; evidence suggests that androgen exposure may suppress innate control of infection in the urinary tract, but additional androgen effects, as well as non-hormonal sex effects, may yet be specified. Among other intriguing directions, recent experiments raise the hypothesis that the postnatal testosterone surge that occurs in male infants may represent an additional factor driving the higher incidence of UTI in males under 6 months of age. Ongoing work in contemporary models will further illuminate sex- and sex-hormone-specific effects on UTI pathogenesis and immune responses.

Prediction of kidney failure in children with chronic kidney disease and obstructive uropathy

BACKGROUND

Obstructive uropathy (OU) is a leading cause of pediatric kidney injury. Accurate prediction of kidney disease progression may improve clinical outcomes. We aimed to examine discrimination and accuracy of a validated kidney failure risk equation (KFRE), previously developed in adults, in children with OU.

METHODS

We identified 118 children with OU and an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 in the Chronic Kidney Disease in Children study, a national, longitudinal, observational cohort. Each patient's 5-year risk of kidney failure was estimated using baseline data and published parameters for the 4- and 8-variable KFREs. Discriminative ability of the KFRE was estimated using the C statistic for time-to-event analysis. Sensitivity and specificity were evaluated across varying risk thresholds.

RESULTS

Among the 118 children, 100 (85%) were boys, with median baseline age of 10 years (interquartile range, 6-14). Median eGFR was 42 mL/min/1.73m 2 (32-53), with a median follow-up duration of 4.5 years (2.7-7.2); 23 patients (19.5%) developed kidney failure within 5 years. The 4-variable KFRE discriminated kidney failure risk with a C statistic of 0.75 (95% CI, 0.68-0.82). A 4-variable risk threshold of ≥ 30% yielded 82.6% sensitivity and 75.0% specificity. Results were similar using the 8-variable KFRE.

CONCLUSIONS

In children with OU, the KFRE discriminated the 5-year risk of kidney failure at C statistic values lower than previously published in adults but comparable with suboptimal values reported in the overall CKiD population. The 8-variable equation did not improve model discrimination or accuracy, suggesting the need for continued research into additional, disease-specific markers.