Expert Consensus on Pediatric Urodynamics Reporting Using Modified Delphi Technique.

PURPOSE: Urodynamic testing (UDS) is an important tool in the management of pediatric lower urinary tract conditions. There have been notable efforts to standardize pediatric UDS nomenclature and technique, but no formal guidelines exist on essential elements to include in a clinical report. We sought to identify ideal structure and elements of a pediatric UDS assessment based on expert consensus. MATERIALS AND METHODS: Pediatric urologists regularly performing UDS were queried using a Delphi process. Participants were invited representing varied geographic, experience, and societal involvement. Participants underwent 3 rounds of questionnaires between November 2022 and August 2023 focusing on report organization, elements, definitions, and automated electronic health record clinical decision support. Professional billing requirements were also considered. Consensus was defined as 80% agreeing either in favor of or against a topic. Elements without consensus were discussed in subsequent rounds. RESULTS: A diverse sample of 30 providers, representing 27 institutions across 21 US states; Washington, District of Columbia; and Canada completed the study. Participants reported interpreting an average number of 5 UDS reports per week (range 1-22). The finalized consensus report identifies 93 elements that should be included in a pediatric UDS report based on applicable study conditions and findings. CONCLUSIONS: This consensus report details the key elements and structure agreed upon by an expert panel of pediatric urologists. Further standardization of documentation should aid collaboration and research for patients undergoing UDS. Based on this information, development of a standardized UDS report template using electronic health record implementation principles is underway, which will be openly available for pediatric urologists.

Long-term Safety and Tolerability of Repeated Treatments With OnabotulinumtoxinA in Children With Neurogenic Detrusor Overactivity.

PURPOSE: OnabotulinumtoxinA is an approved treatment for neurogenic detrusor overactivity in adults inadequately managed with anticholinergics, and more recently was approved in children on the basis of a phase 3, 48-week, single-treatment study (NCT01852045). Given the paucity of long-term pediatric data, we report on the continued safety in these patients after repeated onabotulinumtoxinA treatment. MATERIALS AND METHODS: This was a multicenter, double-blind, repeat-treatment extension study (NCT01852058) in patients who entered from the preceding single-treatment study. Data were integrated across both studies. All patients (5-17 years) used clean intermittent catheterization and could receive dose escalations based on response to preceding treatment (50 U, 100 U, or 200 U onabotulinumtoxinA [not to exceed 6 U/kg]). RESULTS: Overall, 95, 90, 55, and 11 patients received 1, 2, 3, and 4 treatments with onabotulinumtoxinA, respectively, and median (quartiles) duration of follow-up was 82 (65, 94) weeks. The safety profile was similar across doses and after repeat treatments. The most common treatment-emergent adverse event during cycles 1, 2, and 3 was urinary tract infection (31%, 34%, 22%). Three serious treatment-emergent adverse events related to study treatment (3/95; 3.2%) were reported during the study, which were all cases of urinary tract infection. Annualized urinary tract infection rates post-treatment were similar to pre-screening rates. There were no cases of autonomic dysreflexia, neutralizing antibodies, and treatment-emergent adverse events related to distant spread of toxin. CONCLUSIONS: OnabotulinumtoxinA continued to be well tolerated after repeated treatments in pediatric neurogenic detrusor overactivity patients with similar safety profiles across dose groups. Treatment-emergent adverse events were primarily urological with no new safety concerns.

Effect of Caudal vs. Penile Block on the Incidence of Hypospadias Complications Following Primary Repairs: A Retrospective Cohort Study.

PURPOSE: Primary repair of hypospadias is associated with risk of complications, specifically urethrocutaneous fistula and glanular dehiscence. Caudal block may potentially increase the risk of these complications. Therefore, we studied the incidence of hypospadias complications in children who underwent correction at our institution having received either penile or caudal block. MATERIALS AND METHODS: We analyzed all primary hypospadias repair cases from December 2011 through December 2018 at Texas Children's Hospital with a minimum of 1-year followup for the presence of complications: urethrocutaneous fistula and glanular dehiscence. Surgical (surgeon, operative time, block type, local anesthetic, meatal position) and patient (age at correction, prematurity) factors were additionally analyzed. RESULTS: For the primary aim, 983 patients underwent primary hypospadias correction with a minimum of 1 year of postoperative followup data. There were 897 patients (91.3%) in which no complications were identified and 86 (8.7%) with either urethrocutaneous fistula (81) or glanular dehiscence (5). Of the 86 identified complications, 45/812 (5.5%) were distal, 41/171 (24%) were proximal (p <0.001) with a complication. Rate of complications was not associated with caudal block (OR 0.67, 95% CI 0.41-1.09; p=0.11). On univariable analysis, age (OR 1.12, 95% CI 1.04-1.20; p=0.04), surgical duration (OR 1.02; 95% CI 1.01-1.02; p <0.001), prematurity <32 weeks (OR 4.38, 95% CI 1.54-4.11 p <0.001) and position of meatus as proximal (OR 5.38 95% CI 3.39-8.53; p <0.001) were associated with an increased rate of complications. However, on multivariable analysis, associations of age (OR 1.13, 95% CI 1.05-1.22; p=0.001), surgery duration (OR 1.01, 95% CI 1.01-1.02; p <0.001) and meatal position (OR 3.85, 95% CI 2.32-6.39; p <0.001) were associated with increased rate of complications. CONCLUSIONS: Our data suggest that meatal location, older age, extreme prematurity and surgical duration are associated with increased incidence of complications (urethrocutaneous fistula and glanular dehiscence) following hypospadias correction. Analgesic block was not associated with increased hypospadias complication risk.

Robinow syndrome: Genital analysis, genetic heterogeneity, and associated psychological impact.

Robinow syndrome (RS) is a rare, pleiotropic genetic disorder. While it has been reported that males with Robinow syndrome may have genitourinary atypicalities, these have not been systematically studied. We hypothesized that the underlying gene involved plays a role in the clinical variability of associated genital findings and that the phenotypic appearance of the genitalia in RS may have a psychological impact. Urologic-specific examination consisted of detailed examination and a questionnaire to investigate the psychological impact of the genital phenotype. Nine males agreed to a full evaluation. Average age was 19.9 years, penile length was 32.5 mm, stretched length 53 mm, and width 24.4 mm. Penile transposition occurred in all 9 male who allowed full examination. Undescended testicles were noted in 4/10, testicular atrophy in 5/9, buried penis in 7/9, hypospadias in 5/8, and a large penopubic gap (space between dorsum of penis base and pubic bone) in 5/6. In this cohort, 78% answered our semi-quantitative pilot questionnaire that identified diminished sexuality, sexual function, and self-perception. In conclusion, RS has unique, hallmark genital findings including penile transposition, buried penis, undescended testes, and large penopubic gaps. Genital phenotype in males was not shown to correlate with the specific gene involved for each patient. Surgical approaches and other interventions should be studied to address the findings of decreased sexuality and self-perception. It is the authors' opinion that intervention to provide the appearance of penile lengthening be postponed until puberty to allow for maximal natural phallic growth.

OnabotulinumtoxinA for the treatment of neurogenic detrusor overactivity in children.

AIMS: This study evaluated whether one (or more) of three doses of onabotulinumtoxinA were safe and effective to treat neurogenic detrusor overactivity (NDO) in children. METHODS: This was a 48-week prospective, multicenter, randomized, double-blind study in children (aged 5-17 years) with NDO and urinary incontinence (UI) receiving one onabotulinumtoxinA treatment (50, 100, or 200 U; not to exceed 6 U/kg). Primary endpoint: change from baseline in daytime UI episodes. Secondary endpoints: change from baseline in urine volume at first morning catheterization, urodynamic measures, and positive response on the treatment benefit scale. Safety was also assessed. RESULTS: There was a similar reduction in urinary incontinence from baseline to Week 6 for all doses (-1.3 episodes/day). Most patients reported positive responses on the treatment benefit scale (75.0%-80.5%). From baseline to Week 6, increases were observed in urine volume at first morning clean intermittent catheterization (50 U, 21.9 ml; 100 U, 34.9 ml; 200 U, 87.5 ml; p = 0.0055, 200 U vs. 50 U) and in maximum cystometric capacity (range 48.6-63.6 ml) and decreases in maximum detrusor pressure during the storage phase (50 U, -12.9; 100 U, -20.1; 200 U, -27.3 cmH2 O; p = 0.0157, 200 U vs. 50 U). The proportion of patients experiencing involuntary detrusor contractions dropped from baseline (50 U, 94.4%; 100 U, 88.1%; 200 U, 92.6%) to Week 6 (50 U, 61.8%; 100 U, 44.7%; 200 U, 46.4%). Safety was similar across doses; urinary tract infection was most frequent. CONCLUSIONS: OnabotulinumtoxinA was well tolerated and effective for the treatment of NDO in children; 200 U showed greater efficacy in reducing bladder pressure and increasing bladder capacity.

Prevalence of high-risk bladder categorization with prenatal and postnatal myelomeningocele repair types.

INTRODUCTION: Urologic substudies of prenatal myelomeningocele (MMC) closure have focused primarily on continence without significant clinical benefit. Fetoscopic MMC repair (FMR) is a newer form of prenatal intervention and touts added benefits to the mother, but urological outcomes have yet to be analyzed. We set out to focus on bladder safety rather than continence and examined bladder outcomes with different prenatal MMC repairs (FMR and prenatal open [POMR]) and compared bladder-risk-categorization to traditional postnatal repair (PSTNR). METHODS: An IRB-approved retrospective analysis of all patients undergoing all forms of MMC repairs with inclusion and exclusion criteria based on the MOMS trial was performed. Bladder safety assessment required initial urodynamic studies (UDS), renal bladder ultrasound (RBUS), and/or voiding cystourethrogram (VCUG) within the 1st year of life. Follow-up analyses within the cohorts required follow-up studies within 18 months after initial evaluations. Outcomes assessed included bladder-risk-categorization based on the CDC UMPIRE study (high, intermediate, and safe), hydronephrosis (HN), and vesicoureteral reflux (VUR). A single reader evaluated each UDS. RESULTS: Initial UDS in 93 patients showed that the prevalence of high-risk bladders were 35% FMR versus 36% PSTNR and 60% POMR. Follow-up UDS showed only 8% of FMR were high-risk compared to 35% POMR and 36% PSTNR. Change from initial to follow-up bladder-risk-category did not reach significance (p = .0659); however, 10% PSTNR worsened to high-risk on follow-up, compared to none in either prenatal group. Subanalysis of follow-up UDS between the prenatal cohorts also was not significant (p = .055). Only 8% of FMR worsened or stayed high-risk compared to 35% with POMR (p = .1). HN was significantly different at initial and subsequent follow up between the groups with the least in the FMR group. CONCLUSIONS: Early outcome UDS analyses demonstrated lower incidence of high-risk bladders in FMR patients with a trend toward clinically significant improvement compared to POMR in regard to all evaluated metrics. Larger, prospective, confirmatory studies are needed to further evaluate the potential benefits on FMR on bladder safety and health.

Distress Trajectories for Parents of Children With DSD: A Growth Mixture Model.

OBJECTIVE: This study identifies trajectories of parent depressive symptoms after having a child born with genital atypia due to a disorder/difference of sex development (DSD) or congenital adrenal hyperplasia (CAH) and across the first year postgenitoplasty (for parents who opted for surgery) or postbaseline (for parents who elected against surgery for their child). Hypotheses for four trajectory classes were guided by parent distress patterns previously identified among other medical conditions. METHODS: Participants included 70 mothers and 50 fathers of 71 children diagnosed with a DSD or CAH with reported moderate to high genital atypia. Parents were recruited from 11 US DSD specialty clinics within 2 years of the child's birth and prior to genitoplasty. A growth mixture model (GMM) was conducted to identify classes of parent depressive symptoms over time. RESULTS: The best fitting model was a five-class linear GMM with freely estimated intercept variance. The classes identified were termed "Resilient," "Recovery," "Chronic," "Escalating," and "Elevated Partial Recovery." Four classes have previously been identified for other pediatric illnesses; however, a fifth class was also identified. The majority of parents were classified in the "Resilient" class (67.6%). CONCLUSIONS: This study provides new knowledge about the trajectories of depressive symptoms for parents of children with DSD. Future studies are needed to identify developmental, medical, or familial predictors of these trajectories.

Patient and Caregiver Attitudes toward Disorders of Sex Development Nomenclature.

PURPOSE: The medical terminology applied to differences/disorders of sex development has been viewed negatively by some affected individuals. A clinical population of patients with differences/disorders of sex development and their caregivers were surveyed regarding current nomenclature, hypothesizing that those unaffiliated with support groups would have more favorable attitudes. MATERIALS AND METHODS: We recruited English and Spanish speaking patients 13 years old or older with differences/disorders of sex development and their caregivers at 5 national tertiary care clinics from July 2016 to December 2018. No diagnoses were excluded. Participants completed a survey rating terminology commonly applied to differences/disorders of sex development. Responses were compared between subgroups, including members vs nonmembers of a support group. RESULTS: Of 185 potential participants approached 133 completed the survey (72% response rate). Congenital adrenal hyperplasia (33%) was the most common diagnosis. "Variation of sex development" was the most liked term (37%) but was not liked more significantly than "disorders of sex development" (27%, p=0.16). No term was liked by a majority of respondents. "Disorders of sex development" (37%) and "intersex" (53%) were the only terms most frequently viewed unfavorably. Support group members were significantly more likely to dislike the term "intersex" (p=0.02) and to like "variation of sex development" (p=0.02). CONCLUSIONS: A clinical population of patients and their caregivers had generally neutral attitudes toward nomenclature applied to differences/disorders of sex development. Members of a support group had clearer terminology preferences. "Variation of sex development" was the most liked term, and "disorders of sex development" and "intersex" were the most disliked. No term was liked by most respondents, and no clear alternative to the present nomenclature was identified.

Illness Uncertainty Longitudinally Predicts Distress Among Caregivers of Children Born With DSD.

OBJECTIVE: A subset of parents of children with disorders/differences of sex development (DSD) including ambiguous genitalia experience clinically elevated levels of anxious and depressive symptoms. Research indicates that uncertainty about their child's DSD is associated with parent psychosocial distress; however, previous studies have been cross-sectional or correlational in nature. The current study is the first to examine the longitudinal trajectory of the relationship between caregiver-perceived uncertainty about their child's DSD and caregiver anxious and depressive symptoms across the first 12 months following genital surgery in young children, or if surgery was not performed, the first 12 months following study entry. METHODS: One hundred and thirteen caregivers (Mage = 32.12; 57.5% mothers; 72.6% Caucasian) of children (N = 70; Mage = 9.81 months; 65.7% female) with DSD were recruited from 12 DSD specialty clinics in the United States. Caregivers completed psychosocial measures at baseline, 6 and 12 months following genitoplasty, or study entry if parents elected not to have surgery for their child. RESULTS: Caregiver illness uncertainty and both anxious and depressive symptoms were highest at baseline and decreased over time (ps < .05). Caregiver illness uncertainty predicted symptoms of anxious and depressive symptoms across all time points (ps < .05). CONCLUSIONS: Caregivers' perceptions of uncertainty about their child's DSD are highest soon after diagnosis, and uncertainty continues to predict both anxious and depressive symptoms across time. Thus, the initial diagnostic period is a critical time for psychological assessment and intervention, with parent illness uncertainty being an important clinical target.

Analysis of 1478 Cases of Hypospadias Repair: The Incidence of Requiring Repeated Anesthetic Exposure as Well as Exploration of the Involvement of Trainees on Case Duration.

BACKGROUND: Recently, there has been significant focus on the effects of anesthesia on the developing brain. Concern is heightened in children <3 years of age requiring lengthy and/or multiple anesthetics. Hypospadias correction is common in otherwise healthy children and may require both lengthy and repeated anesthetics. At academic centers, many of these cases are performed with the assistance of anesthesia and surgical trainees. We sought to identify both the incidence of these children undergoing additional anesthetics before age 3 as well as to understand the effect of trainees on duration of surgery and anesthesia and thus anesthetic exposure (AE), specifically focusing on those cases >3 hours. METHODS: We analyzed all cases of hypospadias repair from December 2011 through December 2018 at Texas Children's Hospital. In all, 1326 patients undergoing isolated hypospadias repair were analyzed for anesthesia time, surgical time, provider types involved, AE, caudal block, and additional AE related/unrelated to hypospadias. RESULTS: For the primary aim, a total of 1573 anesthetics were performed in children <3 years of age, including 1241 hypospadias repairs of which 1104 (89%) were completed with <3 hours of AE. For patients with <3 hours of AE, 86.1% had a single surgical intervention for hypospadias. Of patients <3 years of age, 17.3% required additional nonrelated surgeries. There was no difference in anesthesia time in cases performed solely by anesthesia attendings versus those performed with trainees/assistance (16.8 vs 16.8 minutes; P = .98). With regard to surgery, cases performed with surgical trainees were of longer duration than those performed solely by surgical attendings (83.5 vs 98.3 minutes; P < .001). Performance of surgery solely by attending surgeon resulted in a reduced total AE in minimal alveolar concentration (MAC) hours when compared to procedures done with trainees (1.92 vs 2.18; P < .001). Finally, comparison of patients undergoing initial correction of hypospadias with subsequent revisions revealed a longer time (117.7 vs 132.2 minutes; P < .001) and AE during the primary stage. CONCLUSIONS: The majority of children with hypospadias were repaired within a single AE. In general, most children did not require repeated AE before age 3. While presence of nonattending surgeons was associated with an increase in AE, this might at least partially be due to differences in case complexity. Moreover, the increase is likely not clinically significant. While it is critical to maintain a training environment, attempts to minimize AE are crucial. This information facilitates parental consent, particularly with regard to anesthesia duration and the need for additional anesthetics in hypospadias and nonhypospadias surgeries.

Hormones and their Structural and Functional Effects on the Brain: How Can We Change our Practice Moving Forward?

Is hormone treatment an invasive procedure? In this paper, we discuss aspects related to the choice of treating disorders of sex development (DSD) using hormones. Specifically, we focus on some of the challenging issues related to this treatment and the need to establish a standard of care for the use of hormone therapy in this patient population. The objectives of this paper are to: 1) Enhance understanding of the uncertainties in the decision-making process regarding hormonal interventions to treat patients with DSD. 2) Recognize that the effects of hormonal interventions might require a consent process similar to that applied for surgical procedures. 3) Emphasize the need to establish treatment algorithms that could form the basis of a standard of care for this patient population.

Lower Urinary Tract Dysfunction and Associated Pons Volume in Patients with Wolfram Syndrome.

PURPOSE: Wolfram syndrome is a neurodegenerative disorder characterized by childhood onset diabetes mellitus, optic nerve atrophy, diabetes insipidus, hearing impairment, and commonly bladder and bowel dysfunction. We hypothesized that there is an association between a smaller pons, which contains the pontine micturition center, and abnormal lower urinary tract function. MATERIALS AND METHODS: Patients with genetically confirmed Wolfram syndrome attended an annual multidisciplinary research clinic. Subjects underwent noninvasive urodynamic testing and brain magnetic resonance imaging, and completed validated patient reported outcome measures. Bowel and bladder diaries were completed before visits. Age and gender corrected linear and logistic mixed effects models were used to correlate pons volume, corrected for whole brain size, to urodynamic and patient reported outcomes. RESULTS: A total of 36 patients attended 142 visits between 2010 and 2016. Mean age was 16.9 years (range 7 to 30) and 64% of patients were female. Functional bladder capacity was decreased in 31% of the patients, normal in 54% and increased in 14%. Of the patients 44% and 54% had abnormal uroflowmetry and post-void residual, respectively, on at least 1 occasion. There was no increase through time in incidence of lower urinary tract dysfunction. Decreased pons volume was associated with increased post-void residual (p = 0.048) and higher PinQ (Pediatric Incontinence Questionnaire) score (p = 0.011), indicating lower quality of life and higher levels of dysfunction. CONCLUSIONS: A significant number of children, adolescents and young adults with Wolfram syndrome have objective evidence of lower urinary tract dysfunction. Decreased pons volume is associated with more abnormal urinary function and lower quality of life in patients with Wolfram syndrome.

Evaluation and management of tethered cord syndrome in occult spinal dysraphism: Recommendations from the international children's continence society.

AIMS: As awareness and frequency of tethered spinal cord (TSC) related to occult spinal dysraphism (OSD) has increased with magnetic resonance imaging (MRI), variability exists in its evaluation and management. Due to no published level I data, we summarize the current International Children's Continence Society (ICCS) recommendations for diagnosis and treatment of OSD. METHODS: Guidelines were formulated based on analysis of pertinent literature and consensus among authors. This document was vetted by the multidisciplinary members of the ICCS via its website before submission for peer review publication. RESULTS: The more frequent diagnosis of OSD is associated with increased operative intervention. Spinal cord untethering (SCU) has a highly variable risk profile, largely dependent on the specific form of OSD. Progressive neurological deterioration attributed to "tethered cord" may occur, with or without surgery, in selected forms of OSD whereas other cohorts do well. CONCLUSION: Infants with classic cutaneous markers of OSD, with progressive neurologic, skeletal, and/or urologic findings, present no diagnostic or therapeutic dilemma: they routinely undergo MRI and SCU. Conversely, in asymptomatic patients or those with fixed, minor abnormalities, the risk profile of these OSD cohorts should be carefully considered before SCU is performed. Irrespective of whether or not SCU is performed, patients at risk for progression should be followed carefully throughout childhood and adolescence by a multidisciplinary team.

The standardization of terminology of lower urinary tract function in children and adolescents: Update report from the standardization committee of the International Children's Continence Society.

AIM: The impact of the original International Children's Continence Society (ICCS) terminology document on lower urinary tract (LUT) function resulted in the global establishment of uniformity and clarity in the characterization of LUT function and dysfunction in children across multiple healthcare disciplines. The present document serves as a stand-alone terminology update reflecting refinement and current advancement of knowledge on pediatric LUT function. METHODS: A variety of worldwide experts from multiple disciplines within the ICCS leadership who care for children with LUT dysfunction were assembled as part of the standardization committee. A critical review of the previous ICCS terminology document and the current literature was performed. Additionally, contributions and feedback from the multidisciplinary ICCS membership were solicited. RESULTS: Following a review of the literature over the last 7 years, the ICCS experts assembled a new terminology document reflecting current understanding of bladder function and LUT dysfunction in children using the resources from the literature review, expert opinion and ICCS member feedback. CONCLUSIONS: The present ICCS terminology document provides a current and consensus update to the evolving terminology and understanding of LUT function in children. Neurourol. Urodynam. 35:471-481, 2016. © 2015 Wiley Periodicals, Inc.

Adam10 mediates the choice between principal cells and intercalated cells in the kidney.

A disintegrin and metalloproteinase domain 10 (Adam10), a member of the ADAM family of cell membrane-anchored proteins, has been linked to the regulation of the Notch, EGF, E-cadherin, and other signaling pathways. However, it is unclear what role Adam10 has in the kidney in vivo. In this study, we showed that Adam10 deficiency in ureteric bud (UB) derivatives leads to a decrease in urinary concentrating ability, polyuria, and hydronephrosis in mice. Furthermore, Adam10 deficiency led to a reduction in the percentage of aquaporin 2 (Aqp2)(+) principal cells (PCs) in the collecting ducts that was accompanied by a proportional increase in the percentage of intercalated cells (ICs). This increase was more prominent in type A ICs than in type B ICs. Foxi1, a transcription factor important for the differentiation of ICs, was upregulated in the Adam10 mutants. The observed reduction of Notch activity in Adam10 mutant collecting duct epithelium and the similar reduction of PC/IC ratios in the collecting ducts in mice deficient for mindbomb E3 ubiquitin protein ligase 1, a key regulator of the Notch and Wnt/receptor-like tyrosine kinase signaling pathways, suggest that Adam10 regulates cell fate determination through the activation of Notch signaling, probably through the regulation of Foxi1 expression. However, phenotypic differences between the Adam10 mutants, the Mib1 mutants, and the Foxi1 mutants suggest that the functions of Adam10 in determining the fate of collecting duct cells are more complex than those of a simple upstream factor in a linear pathway involving Notch and Foxi1.

Transcriptional dysregulation in the ureteric bud causes multicystic dysplastic kidney by branching morphogenesis defect.

PURPOSE: The calcineurin-NFAT signaling pathway regulates the transcription of genes important for development. It is impacted by various genetic and environmental factors. We investigated the potential role of NFAT induced transcriptional dysregulation in the pathogenesis of congenital abnormalities of the kidneys and urinary tract. MATERIALS AND METHODS: A murine model of conditional NFATc1 activation in the ureteric bud was generated and examined for histopathological changes. Metanephroi were also cultured in vitro to analyze branching morphogenesis in real time. RESULTS: NFATc1 activation led to defects resembling multicystic dysplastic kidney. These mutants showed severe disorganization of branching morphogenesis characterized by decreased ureteric bud branching and the disconnection of ureteric bud derivatives from the main collecting system. The orphan ureteric bud derivatives may have continued to induce nephrogenesis and likely contributed to the subsequent formation of blunt ended filtration units and cysts. The ureter also showed irregularities consistent with impaired epithelial-mesenchymal interaction. CONCLUSIONS: This study reveals the profound effects of NFAT signaling dysregulation on the ureteric bud and provides insight into the pathogenesis of multicystic dysplastic kidney. Our results suggest that the obstruction hypothesis and the bud theory may not be mutually exclusive to explain the pathogenesis of multicystic dysplastic kidney. Ureteric bud dysfunction such as that induced by NFAT activation can disrupt ureteric bud-metanephric mesenchyma interaction, causing primary defects in branching morphogenesis, subsequent dysplasia and cyst formation. Obstruction of the main collecting system can further enhance these defects, producing the pathological changes associated with multicystic dysplastic kidney.

Cell type specific changes in BMP-7 expression contribute to the progression of kidney disease in patients with obstructive uropathy.

PURPOSE: Congenital urinary tract obstruction is a leading cause of renal maldevelopment and pediatric kidney disease. Nonetheless, few groups have examined its molecular pathogenesis in humans. We evaluated the role of BMP-7, a protein required for renal injury repair and nephrogenesis, in disease progression in patients with obstructive uropathy. MATERIALS AND METHODS: Whole kidney and cell specific BMP-7 expression was examined in a murine model of unilateral ureteral obstruction and in patients with congenital ureteropelvic junction obstruction. Findings were correlated with molecular markers of renal injury and clinical parameters. RESULTS: Unilateral ureteral obstruction led to a dramatic decrease in BMP-7 expression in the proximal and distal tubules before the onset of significant loss of renal architecture and fibrosis, suggesting that this is a critical molecular event that drives early stage disease progression. Loss of BMP-7 expression then extended to the collecting ducts and glomeruli in end stage kidney disease. When translating these findings to patients with ureteropelvic junction obstruction, global loss of BMP-7 expression correlated with a decreased number of nephrons, loss of renal architecture, severe renal fibrosis and loss of kidney function. CONCLUSIONS: Given that BMP-7 has a critical role in renal injury repair and nephrogenesis, these findings show that cell specific changes in BMP-7 expression contribute to the onset of irreversible renal injury and impaired kidney development secondary to congenital urinary tract obstruction. Accordingly therapies that target these cell populations to restore BMP-7 activity may limit disease progression in patients with obstructive uropathy.