Safety and Efficacy of Robot-Assisted Laparoscopic Pyeloplasty Compared to Open Repair in Infants under 1 Year of Age.

PURPOSE: Robot-assisted laparoscopic pyeloplasty (RALP) use in children has increased, though many centers still favor open pyeloplasty (OP) in infants. This study aims to compare safety and efficacy of RALP and OP in infants. MATERIALS AND METHODS: A single-institution, retrospective cohort study of infants <1 year of age who underwent primary RALP or OP between January 2009 and June 2020 was performed. Primary outcomes were intraoperative and 30-day complications, postoperative radiographic improvement at last clinic visit, and operative failure leading to redo pyeloplasty. Multivariable logistic regression was performed for 30-day complications to adjust for demographic variation between groups. Survival analysis was performed to compare time to diagnosis of operative failure leading to redo pyeloplasty. RESULTS: Among 204 patients, 121 underwent OP and 83 underwent RALP (74.5% male). RALP patients were older (median 7.2 vs 2.9 months, p <0.001) and larger (median 8.2 vs 5.9 kg, p <0.001) than OP patients. Radiographic improvement was seen in 91.1% of RALP patients and 88.8% of OP patients at last visit. Median (interquartile range) followup in months was 24.4 (10.8-50.3) for the full cohort. In adjusted analysis, the odds of a 30-day complication (OR 0.40, 95% CI 0.08-2.00) was lower for RALP compared to OP, though not statistically significant. In survival analysis, there was no difference in time to diagnosis of operative failure and redo pyeloplasty between groups (p=0.65). CONCLUSIONS: RALP is a safe and effective alternative to OP for infants, with comparable intraoperative and 30-day complications, radiographic improvement at last followup, and risk of pyeloplasty failure.

Relation between Cajal Cell Density and Radiological and Scintigraphic Outcomes in Patients with Ureteropelvic Junction Obstruction.

INTRODUCTION: In this study, we aimed to investigate the correlation between Cajal cell density and preoperative and postoperative radiological and scintigraphic parameters in ureteropelvic junction obstruction (UPJO). METHODS: The study group consisted of 41 renal units (38 consecutive patients; 13 female and 25 male) surgically treated for UPJO. UPJ specimens from patients were immuno-stained with CD117 (c-kit) antibody for interstitial Cajal cells (ICCs). The relation between Cajal cell density and preoperative and postoperative radiological and scintigraphic parameters was evaluated. RESULTS: The mean age of the patients was 8.52 ± 8.86 (0-35) years. The density of Cajal cells was defined in 2 groups for convenient analysis as 0-5 cells (low) in 19 (46.3%) patients and >5 cells (moderate-high) in 22 (53.6%). There was significant difference between the preoperative and postoperative anteroposterior diameters of the related kidneys in both Cajal groups (p = 0.001-low, p = 0.000-moderate-high) independent of Cajal cell density. Regression in hydronephrosis postoperatively was determined in both Cajal groups (77.8%-low, 64.7%-moderate-high); however, there was no difference between them (p = 0.39). Preoperative T1/2 was significantly longer in the low Cajal group (p = 0.02). Postoperative T1/2 decreased in both low (p = 0.000) and moderate-high (p = 0.001) Cajal groups, but no difference was found between them (p = 0.24). There was significant improvement in the kidney differential function after surgery in the low Cajal density group (p = 0.015) while there was no correlation between the scintigraphic success or improvement and Cajal cell density (p = 0.51). DISCUSSION/CONCLUSION: ICC deficiency/density could not be shown as a predictive factor for the determination of success rate of pyeloplasty. Despite the lack of any evidence for the degree of deficiency as an indicator for the severity of obstruction and prediction of surgical success, further studies are needed for confirmation.

Hybrid Retroperitoneoscopic Pyeloplasty for Congenital Ureteropelvic Junction Obstruction in Infants Weighing Less than 10 kg.

Introduction: Success rate of laparoscopic pyeloplasty for ureteropelvic junction obstruction (UPJO) in children is comparable with open pyeloplasty. Prolonged ileus and injury to adjacent viscera more often occurred in transperitoneal approach; however, longer operation time is noted in retroperitoneal approach. Purpose: This study presented a hybrid retroperitoneoscopic pyeloplasty (HRP), for congenital UPJO in infants weighing <10 kg. Materials and Methods: From February 2017 to June 2020, 10 HRP procedures were performed in 9 patients by 1 surgeon. Retroperitoneal dissection of the renal pelvis and the upper third ureter was first performed, followed by extracorporeal suturing for pyeloureterostomy. Results: Mean operative age and body weight were 4.23 ± 3.69 months and 6.18 ± 1.57 kg. Operative, CO2 inflation, and extracorporeal suture time were 147.9 ± 39.5, 40.6 ± 11.2, and 62.9 ± 26.1 minutes, respectively. Surgical outcome was confirmed by renal ultrasound and diuretic renogram. Postoperative follow-up duration was 15.2 ± 7.7 months. Three patients had postoperative febrile urinary tract infection and recovered after antibiotic treatment. Conclusion: In infants or smaller children with UPJO, the HRP procedure may be considered as an effective and minimally invasive alternative with shorter learning curve for inexperienced surgeons.

iTRAQ-based proteomics and in vitro experiments reveals essential roles of ACE and AP-N in the renin-angiotensin system-mediated congenital ureteropelvic junction obstruction.

OBJECTIVE: Ureteropelvic junction obstruction (UPJO) is a common renal obstructive disorder, but its pathogenic mechanisms remain largely unclear. We aimed to investigate the potential involvement of the renin-angiotensin system in congenital UPJO pathogenesis. METHODS: Differentially expressed proteins in exosomes isolated from amniotic fluid of patients with congenital UPJO were characterized using iTRAQ (isobaric tags for relative and absolute quantification)-based proteomics. The expressions of angiotensin-converting enzyme (ACE) and aminopeptidase N (AP-N) in HK2 cells were inhibited by quinapril and siRNA, respectively. Cell proliferation and reactive oxygen species were measured by EdU staining and flow cytometry, respectively. Gene expression was detected by Western blot or qRT-PCR. The inflammatory factors were measured through ELISA. Mice that underwent unilateral ureteral obstruction were used as the animal model. RESULTS: The identity of exosomes from amniotic fluids was confirmed by the expression of CD9 and CD26. In total, 633 differentially expressed proteins were identified in the amniotic fluid-derived exosomes from patients with UPJO, including 376 up- and 257 down-regulated proteins associated with multiple biological processes. Of them, ACE and AP-N were significantly decreased in the amniotic fluid exosomes. Inhibition of ACE and AP-N resulted in suppressed cell proliferation; repressed IARP, AT1R, and MAS1 expression; elevated ROS production; and increased IL-1ß, TNF-α, and IL-6 levels in HK2 cells. Decreased ACE expression and elevated IL-1ß levels were also observed in the mouse model. CONCLUSION: Suppression of ACE and AP-N expression mediates congenital UPJO pathogenesis by repressing renal tubular epithelial proliferation, promoting ROS production, and enhancing inflammatory factor expression.

Renal Hemodynamic Changes and Postsurgical Recovery in Children Treated for Ureteropelvic Junction Obstruction.

OBJECTIVE: The aims of the study were to measure renal hemodynamic indexes and to evaluate postsurgical recovery in children diagnosed with obstructive hydronephrosis using color Doppler ultrasound. METHODS: This study enrolled 36 patients with ureteropelvic junction obstruction who underwent Anderson-Hynes pyeloplasty. The peak systolic velocity (PSV) and the resistive index (RI) of the main renal arteries (MRAs) and interlobar renal arteries (IRAs) were measured using color Doppler ultrasound. Renal hemodynamic indexes were measured before surgery and 2, 4, 6, 8, 10, 12, 14, and 16 weeks after surgery. RESULTS: Split renal function and renal parenchymal thickness were positively correlated with PSV and negatively correlated with RI. Anterior-posterior diameter had no significant correlation with PSV or RI. The PSV in MRAs and IRAs were lower than those of the contralateral kidneys but increased after surgery. Anderson-Hynes pyeloplasty was successfully performed in all patients, including one patient whose kidney was removed 16 weeks after surgery. The RI in the MRAs and IRAs were higher than those of the contralateral kidneys but decreased within 2 weeks after surgery. Peak systolic velocity and RI were still atypical 16 weeks after surgery. The hemodynamic index of the nonfunctional kidney did not show improvement after surgery. CONCLUSIONS: Peak systolic velocity and RI were correlated with renal function and renal parenchymal thickness but were not correlated with dilatation of the renal pelvis. Peak systolic velocity increased whereas RI decreased after surgery and were stable at 8 weeks, but remained abnormal 16 weeks after surgery. Hemodynamic measurements may be a useful and convenient method to evaluate surgical outcomes after Anderson-Hynes pyeloplasty.

[Diagnostic management of primary megaureter : Voiding cystourethrography obligatory, scintigraphy useful?] / Diagnostisches Management des primären Megaureters : Miktionszysturethrographie obligat, Szintigraphie sinnvoll?

A primary, congenital megaureter means a dilatation of the ureter with a ureteric diameter ≥7 mm due to a structural or functional obstruction of the ureterovesical junction and represents the second most likely cause of neonatal hydronephrosis. Conservative management is the primary treatment option for many patients due to a high spontaneous remission rate of up to 85%. Concerning diagnostic management, meticulous and repeat postnatal evaluation by ultrasound is mandatory to identify patients who are at risk of renal deterioration. Routine voiding cystourethrography or contrast-enhanced voiding urosonography is currently recommended for all patients to detect vesicoureterorenal reflux and other concomitant pathologies. The relevance of the additional information provided by this examination must be critically questioned considering the lack of clinical consequences. Moreover, the question arises as to whether these examinations should be prolonged until clinical symptoms occur. Nevertheless, a subvesical obstruction should still be ruled out for male patients with a bilateral megaureter. The same critical discussion is necessary for the routine use of diuretic renography in patients with primary megaureter. In principal, this examination is used to determine the global as well as the split renal function and in addition is considered to offer an evaluation of the extent of obstruction. Similarly, the question arises of whether this examination should be mandatory for every child with a primary megaureter or whether the decision should be based on the extent of the upper urinary tract dilatation. The trend of diagnostic management should go towards individualized and risk-adapted diagnostic measures.

Moderate and severe fetal pyelectasis: Correlation between prenatal aspects and postnatal outcome.

BACKGROUND: Renal pelvic dilatation (RPD) is a frequent finding in fetal ultrasound. The aim of the study is to correlate the prenatally detected moderate and severe pyelectasis with the postnatal outcome. METHODS: A retrospective analysis involving 90 cases of prenatally detected moderate and severe RPD referred to our prenatal diagnosis centre with 18 months of urological follow-up. Prenatal ultrasound was correlated with postnatal renal function, assessed by plasmatic creatinine and/or renal scintigraphy performed before surgery. RESULTS: Cases were divided between two groups according to postnatal management: group A including 35 newborns (38.9%) that needed surgical treatment and group B with 55 patients (61.1%) who were managed conservatively. The group A presented higher median RPD (18 mm, IQR 12-25 mm) compared to the group B (11 mm, IQR 10-14 mm). The most common anomaly detected within group A was pelvi-ureteric junction (PUI) obstruction (43%). Within group B 32 cases (58%) showed spontaneous resolution of hydronephrosis during postnatal follow up. In case of moderate pyelectasis the risk of postnatal surgery was 25% and raised to 60% for severe RPD. In our study, 29 newborns showed pathologic scintigraphies: 25 required surgery while 4 did not find indication for surgery due to ipsilateral renal function irreversible damage. 6 patients had high creatinine level (>0.6 mg/dl). 35 cases out of 90 (39%) developed monolateral irreversible renal function impairment. CONCLUSION: Moderate and severe RPD are often correlated with postnatal renal damage, therefore a close multidisciplinary follow-up is required. Prenatal scanning is highly predictive of postnatal outcome and can address properly the prenatal counseling.

Urinary polyomavirus: novel biomarker of congenital ureteropelvic junction obstruction.

BACKGROUND: Pregnancy is associated with reactivation and transmission of latent polyomavirus to fetus. Polyomavirus is also known to cause ureteral stenosis and hydronephrosis. OBJECTIVE: The aim of this study was to investigate whether the urinary polyomavirus could be used as a potential biomarker in newborns with ureteropelvic junction obstruction (UPJO). STUDY DESIGN: Urinary polyomavirus virus was measured by PCR in 42 newborn infants with fetal hydronephrosis history. Random urine samples were obtained from newborns immediately after birth and from their mothers at the time of delivery. Results were compared with 25 healthy infants matched for gestational and postnatal ages. The diagnosis of UPJO was established by diuretic renal scintigraphy. UPJO was graded according to the Society for Fetal Urology (SFU) classification. RESULTS: The urine samples of healthy infants showed no detectable polyomavirus. No statistically significant difference was found in the median urinary polyomavirus level between grade 1 (1000 copies/mL) and grade 2 (1500 copies/mL) UPJO infants. When the median urinary BKV values were compared for each grade of UPJO, patients with grade 3 and 4 had significantly higher urinary polyomavirus levels than those with grades 1 or 2 (P < 0.001). There was a strong correlation between the median polyomavirus in the urine of pregnant women and the urine of newborns with UPJO (P < 0.001). DISCUSSION: Data suggest that routine screening of urinary polyomavirus may help to identify infants with severe obstruction in whom early surgical intervention could reduce the risk of developing progressive kidney disease. To the best of our knowledge this is the first prospective study to present the role of urinary polyomavirus in newborn infants with UPJO to distinguish between patients who would benefit from early surgical intervention. CONCLUSION: Urinary polyomavirus is a potential biomarker of UPJO in newborns with fetal hydronephrosis.

Management of hydroureteronephrosis secondary to an aberrant middle rectal artery in a patient with congenital unilateral renal agenesis.

Presented here is the case of a 21-year-old man, with a family history of unilateral renal agenesis, who presented with obstruction of his solitary functioning right kidney. Initially thought to be secondary to an obturator fossa hernia on endoscopic and retrograde pyelography assessment, diagnosis of obstruction secondary to an aberrant middle rectal artery was determined at laparotomy and division of this vessel relieved the patient's obstruction without any short-term or long-term complications. To the best of the authors' knowledge, this is the first reported case in the literature of hydroureteronephrosis secondary to an aberrant middle rectal artery.

Congenital Unilateral Ureteral Stenosis With Hydronephrosis in a Kitten.

A 4-month-old, intact male, domestic longhair cat was admitted with a 2-month history of abdominal distention. Physical examination revealed a mild inspiratory distress and a large palpable intraabdominal mass, in an otherwise bright and alert cat. Abdominal ultrasonography revealed a large hypoechoic cystic structure compatible with hydronephrosis or a renal cyst. On exploratory celiotomy, hydronephrosis of the right kidney was documented and ureteronephrectomy was performed. Histopathology of the excised tissues revealed severe stenosis in the proximal ureteral lumen without evidence of obstructive material, a normal ureteral epithelium and severe atrophy of the renal cortex and medulla, supporting the diagnosis of congenital unilateral ureteral stenosis. The cat recovered uneventfully and 8 months later was in excellent clinical condition. Congenital ureteral stenosis with secondary hydronephrosis may occur rarely in cats and should be included in the differential diagnosis of progressive abdominal distention in young cats.

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.

Clinical Profile and Outcome of Children with Congenital Obstructive Uropathy.

OBJECTIVES: To study the etiology and clinical profile of congenital obstructive uropathy in children, renal status and growth at diagnosis and at follow-up and to determine the predictors for development of chronic kidney disease (CKD). METHODS: An observational (retrospective-prospective) study was conducted at a tertiary care hospital in South India from September 2014 through September 2016. Sixty children diagnosed to have congenital obstructive uropathy with a minimum follow-up period of 5 y were included and followed up prospectively for 2 more years during the study period. The data of the children at admission and follow-up was obtained from the medical records and analyzed. RESULTS: Congenital uretero-pelvic junction obstruction followed by Posterior urethral valve were the most common etiologies identified. Male preponderance (88.3%) was observed with poor urinary stream being the most common presentation (36.6%). Forty percent of the population had elevated creatinine. Fifteen percent were hypertensive and 25% had growth failure at diagnosis. However, there was a reduction in the number of children with poor estimated glomerular filtration rate (eGFR), hypertension and growth faltering during follow-up. Among the risk factors, hypertension at diagnosis [O.R-12.8 (2.21-74.22) and p value <0.05] and frequent urinary tract infection (UTI) [O.R-14.06 (2.32-85.42) and p value <0.05] were the most important factors for CKD progression. Children with low eGFR (< 60 ml/min/1.73m2) had more height faltering and hypertension at follow-up (p value <0.05). CONCLUSIONS: Hypertension and frequent UTI were observed to be strongly associated with progression of CKD. Estimated GFR was found to be significantly associated with faltering of height and hypertension. Preserving the renal function prevents growth faltering and development of hypertension at follow-up thereby ensuring a better quality of life.

Elevated urinary lipocalin-2, interleukin-6 and monocyte chemoattractant protein-1 levels in children with congenital ureteropelvic junction obstruction.

INTRODUCTION: In children with congenital ureteropelvic junction obstruction (UPJO), urinary biomarkers could assist in the diagnosis of renal damage or kidneys at risk for damage. Urinary levels of interleukin-6 (IL6), neutrophil gelatinase-associated lipocalin (LCN2), monocyte chemoattractant protein-1 (MCP1), and transforming growth factor-ß1 (TGFB1) proteins have been correlated with renal damage in several contexts. Whether they might be useful non-invasive biomarkers of obstructive nephropathy due to unilateral and bilateral congenital UPJO was tested. PATIENTS AND METHODS: A cohort study was performed at People's Hospital of Xinjiang Uygur Autonomous Region in China. Bladder urine samples from 17 patients with UPJO were obtained before surgical intervention and from 17 healthy age-matched controls. Levels of IL6, LCN2, MCP1, and TGFB1 were determined by enzyme-linked immunosorbent assay and normalized to urinary creatinine levels. RESULTS: Levels of urinary LCN2, MCP1, and IL6 were significantly elevated in the urine from individuals with UPJO compared with controls (P = 0.0003, P = 0.0003, and P = 0.0073, respectively). Children with bilateral UPJO (n = 5) showed significantly higher levels of IL6, LCN2, and MCP1 protein in their urine compared with controls or those with unilateral UPJO (n = 12; P = 0.007, P < 0.0001, and P = 0.0002, respectively). Combining LCN2 and MCP1 slightly improved biomarker performance. DISCUSSION: Urinary biomarkers could be used in obstructed patients to monitor for renal damage and might find particular utility on patients with bilateral UPJO. Monitoring urinary biomarkers and imaging features in untreated patients could provide insights into the natural history of renal damage due to obstruction and will be necessary to test their performance characteristics as biomarkers. CONCLUSIONS: Urinary levels of LCN2 and MCP1 protein are promising biomarkers monitoring children with UPJO, particularly in those with bilateral disease.

Common clinical markers predict end-stage renal disease in children with obstructive uropathy.

BACKGROUND: Obstructive uropathy (OU) is a common cause of end-stage renal disease (ESRD) in children. Children who escape the newborn period with mild-to-moderate chronic kidney disease (CKD) continue to be at increased risk. The predictive ability of clinically available markers throughout childhood is poorly defined. METHODS: Patients with OU were identified in the Chronic Kidney Disease in Children Study. The primary outcome of interest was renal replacement therapy (RRT) (cases). Controls were age matched and defined as patients within the OU cohort who did not require RRT during study follow-up. RESULTS: In total, 27 cases and 41 age-matched controls were identified. Median age at baseline and age at outcome measurement were 10 vs. 16 years, respectively. First available glomerular filtration rate (GFR) (36.9 vs. 53.5 mL/min per 1.73 m2), urine protein/creatinine (Cr) (0.40 vs. 0.22 mg/mg) and microalbumin/Cr (0.58 vs. 0.03 mg/mg), and serum CO2 (20 vs. 22 mmol/L) and hemoglobin (12.4 vs. 13.2 g/dL) differed significantly between cases and controls, respectively. GFR declined 3.07 mL/min per 1.73 m2/year faster in cases compared to that in controls (p < 0.0001). Urine protein/Cr and microalbumin/Cr increased by 0.16 and 0.11 per year more in cases compared to those in controls, respectively (p ≤ 0.001 for both). Serum phosphate increased by 0.11 mg/dL and serum albumin and hemoglobin decreased by 0.04 (g/dL) and 0.14 (g/dL) per year more for cases compared to those for controls, respectively (p < 0.05 for all). CONCLUSIONS: Age-specific baseline and longitudinal measures of readily available clinical measures predict progression to ESRD in children with mild-to-moderate CKD from OU.

A modification with threading cannula needle-assisted 4-point suspension fixation for retroperitoneal laparoscopic pyeloplasty in children with ureteropelvic junction obstruction: a cohort study in single center.

PURPOSE: To evaluate the effect and safety of modifying a threading cannula needle-assisted suspension fixation in retroperitoneal laparoscopic dismembered pyeloplasty (LDP) for children with congenital ureteropelvic junction obstruction (UPJO). METHODS: Between December 2012 and December 2017, 45 children (< 14 years of age) with congenital UPJO were divided into two groups. In Group A, children underwent conventional "no-suspension fixation" LDP; and in Group B, "4-point suspension fixation" LDP was performed to lower difficulties and shorten operative time. The perioperative clinical data were recorded and analyzed. RESULTS: No statistical difference was found between two groups in preoperative characteristics. The duration of surgery, operative time for completion of anastomosis and the length of postoperative hospital stay in Group B was remarkably shortened than that in Group A, respectively (P < 0.05 for all). There was no significant difference between two groups in terms of postoperative renal pelvic diameter (RPD) decreasing, extubation time and success rates of surgery (P > 0.05 for all). In addition, no recurrent stenosis and urine leakage in both groups, and the postoperative RPD remained at the low level in both groups during the period of follow-up. CONCLUSIONS: Our modification of the 4-point suspension fixation for retroperitoneal LDP is an effective and safe method for children with UPJO. It can simplify the surgical procedures, lower difficulties (especially in precise anastomotic suturing) and shorten the learning curve. This modification might be of particular interest to urologists for improving treatment of children with UPJO.

Identification of key microRNAs, transcription factors and genes associated with congenital obstructive nephropathy in a mouse model of megabladder.

OBJECTIVE: The present study aimed to investigate the molecular mechanism underlying congenital obstructive nephropathy (CON). METHODS: The microarray dataset GSE70879 was downloaded from the Gene Expression Omnibus, including 3 kidney samples of megabladder mice and 4 control kidneys. Using this dataset, differentially expressed miRNAs (DEMs) were identified between the kidney samples from megabladder mice and controls, followed by identification of the target genes for these DEMs and construction of a DEM and target gene interaction network. Additionally, the target genes were subjected to Gene Ontology and pathway enrichment analyses, and were used for construction of a protein-protein interaction (PPI) network. Finally, regulatory networks were constructed to analyze transcription factors for the key miRNAs. RESULTS: From 17 DEMs identified between kidney samples of megabladder mice and controls, 3 key miRNAs were screened, including mmu-miR-150-5p, mmu-miR-374b-5p and mmu-miR-126a-5p. The regulatory networks identified vascular endothelial growth factor A (Vegfa) as the common target gene of mmu-miR-150-5p and five transcription factors, including nuclear receptor subfamily 4, group A, member 2 (Nr4a2), Jun dimerisation protein 2 (Jdp2), Kruppel-like factor 6 (Klf6), Neurexophilin-3 (Nxph3) and RNA binding motif protein 17 (Rbm17). The gene encoding phosphatase and tensin homolog (Pten) was found to be co-regulated by mmu-miR-374b-5p and high mobility group protein A1 (Hmga1), whereas the kirsten rat sarcoma viral oncogene (Kras) was identified as a common target gene of mmu-miR-126a-5p and paired box 6 (Pax6). CONCLUSIONS: In summary, the above-listed key miRNAs, transcription factors and key genes may be involved in the development of CON.

Activated Hedgehog-GLI Signaling Causes Congenital Ureteropelvic Junction Obstruction.

Intrinsic ureteropelvic junction obstruction is the most common cause of congenital hydronephrosis, yet the underlying pathogenesis is undefined. Hedgehog proteins control morphogenesis by promoting GLI-dependent transcriptional activation and inhibiting the formation of the GLI3 transcriptional repressor. Hedgehog regulates differentiation and proliferation of ureteric smooth muscle progenitor cells during murine kidney-ureter development. Histopathologic findings of smooth muscle cell hypertrophy and stroma-like cells, consistently observed in obstructing tissue at the time of surgical correction, suggest that Hedgehog signaling is abnormally regulated during the genesis of congenital intrinsic ureteropelvic junction obstruction. Here, we demonstrate that constitutively active Hedgehog signaling in murine intermediate mesoderm-derived renal progenitors results in hydronephrosis and failure to develop a patent pelvic-ureteric junction. Tissue obstructing the ureteropelvic junction was marked as early as E13.5 by an ectopic population of cells expressing Ptch2, a Hedgehog signaling target. Constitutive expression of GLI3 repressor in Ptch1-deficient mice rescued ectopic Ptch2 expression and obstructive hydronephrosis. Whole transcriptome analysis of isolated Ptch2+ cells revealed coexpression of genes characteristic of stromal progenitor cells. Genetic lineage tracing indicated that stromal cells blocking the ureteropelvic junction were derived from intermediate mesoderm-derived renal progenitors and were distinct from the smooth muscle or epithelial lineages. Analysis of obstructive ureteric tissue resected from children with congenital intrinsic ureteropelvic junction obstruction revealed a molecular signature similar to that observed in Ptch1-deficient mice. Together, these results demonstrate a Hedgehog-dependent mechanism underlying mammalian intrinsic ureteropelvic junction obstruction.