A mutation affecting laminin alpha 5 polymerisation gives rise to a syndromic developmental disorder.

Laminin alpha 5 (LAMA5) is a member of a large family of proteins that trimerise and then polymerise to form a central component of all basement membranes. Consequently, the protein plays an instrumental role in shaping the normal development of the kidney, skin, neural tube, lung and limb, and many other organs and tissues. Pathogenic mutations in some laminins have been shown to cause a range of largely syndromic conditions affecting the competency of the basement membranes to which they contribute. We report the identification of a mutation in the polymerisation domain of LAMA5 in a patient with a complex syndromic disease characterised by defects in kidney, craniofacial and limb development, and by a range of other congenital defects. Using CRISPR-generated mouse models and biochemical assays, we demonstrate the pathogenicity of this variant, showing that the change results in a failure of the polymerisation of α/ß/γ laminin trimers. Comparing these in vivo phenotypes with those apparent upon gene deletion in mice provides insights into the specific functional importance of laminin polymerisation during development and tissue homeostasis.

High-Frequency US for BK Polyomavirus-associated Nephropathy after Kidney Transplant.

Background BK polyomavirus-associated nephropathy (BKPyVAN) is an important cause of chronic renal allograft dysfunction. However, US features indicative of BKPyVAN have not been fully evaluated. Purpose To assess the value of high-frequency US for the diagnosis of BKPyVAN in kidney transplant recipients. Materials and Methods In this prospective cohort study, participants who tested positive for BK viruria after kidney transplant from September 2019 to January 2021 were evaluated with high-frequency US 1 day before biopsy. Clinical characteristics and US features were compared between participants with and without BKPyVAN. Significant predictors associated with BKPyVAN were determined using logistic regression analyses. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic performance. Results A total of 105 participants who underwent kidney transplant (mean age, 38 years ± 11 [SD]; 63 men) were evaluated; 45 participants were diagnosed with BKPyVAN. Multivariable analysis demonstrated that eccentric hydronephrosis and subcapsular hypoechoic areas were independent factors for BKPyVAN. The AUC for predicting BKPyVAN according to subcapsular hypoechoic areas was 0.66 (95% CI: 0.55, 0.77), with a specificity of 92% (55 of 60 participants). The AUC of combined US (eccentric hydronephrosis plus subcapsular hypoechoic area) and clinical (urine BKPyV DNA load [BKPyV-DNA] plus BK viremia) features was 0.90, with a specificity of 92% (55 of 60 participants). Parenchymal hyperechoic and subcapsular hypoechoic areas were independent factors for differentiating BKPyVAN from transplant rejection. The pooled specificity of subcapsular hypoechoic areas was 96% (21 of 22 participants), with an AUC of 0.67 (95% CI: 0.54, 0.80). For the combination of US (parenchymal echogenicity plus subcapsular hypoechoic area) and clinical (urine BKPyV-DNA plus time since transplant) features, the AUC reached 0.92 and specificity was 82% (18 of 22 participants). Conclusion High-frequency US characteristics are valuable for diagnosing BK polyomavirus-associated nephropathy (BKPyVAN) and distinguishing BKPyVAN from rejection in kidney transplant recipients. © RSNA, 2022 Online supplemental material is available for this article.

Unusual Clinical Presentation of Hodgkin Lymphoma in a Child: Both Spinal Cord Compression and Hydronephrosis.

BACKGROUND: Hodgkin lymphoma (HL) is predominantly a nodal disease with extranodal presentation being uncommon. Presentation with neurological symptoms is not uncommon in adult patients with HL. Subdiaphragmatic involvements are less common especially in childhood. In the literature, there has been no case which presented with both spinal cord compression and bilateral hydronephrosis in pediatric patients with HL. OBSERVATION: We report a 9-year-old boy diagnosed with HL who presented with bilateral hydronephrosis and epidural involvement. CONCLUSION: Differential diagnosis of abdominal mass in patients presenting with spinal cord compression and/or hydronephrosis should include HL. Retrograde J ureteral stenting is the treatment of choice for malignant ureteral obstruction.

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.

Prospective development of a patient-reported outcomes instrument for desmoid tumors or aggressive fibromatosis.

BACKGROUND: Desmoid tumors (or aggressive fibromatosis) are locally infiltrative connective-tissue tumors that can arise in any anatomic location; they can be asymptomatic, or they can result in pain, deformity, swelling, and loss of mobility and/or threaten visceral organs with bowel perforation, hydronephrosis, neurovascular damage, and other complications. Existing clinical trial endpoints such as the Response Evaluation Criteria in Solid Tumors (version 1.1) and progression-free survival are inadequate in capturing treatment efficacy. This study was designed to develop a novel clinical trial endpoint by capturing patient-reported outcomes (PROs). METHODS: Following best practices in qualitative methodology, this study used concept elicitation (CE) interviews to explore desmoid patients' perspectives on key disease-related symptoms and impacts. Qualitative analysis was performed to determine the relative frequency and disturbance of symptoms and impacts as well as other characteristics of these concepts. A draft PRO scale was then developed and tested with cognitive interviewing. Information from the interviews was subsequently incorporated into the refined PRO scale. RESULTS: CE interviews with desmoid patients (n = 31) helped to identify salient concepts and led to a draft scale that included symptom and impact scales. Cognitive interviews were completed with additional patients (n = 15) across 3 phases. Patient input was used to refine instructions, revise and/or remove items, and modify the response scale. This resulted in an 11-item symptom scale and a 17-item impact scale. CONCLUSIONS: This is the first disease-specific PRO instrument developed for desmoid tumors. The instrument is available as an exploratory endpoint in clinical trials. This study highlights the feasibility and challenges of developing PRO instruments for rare diseases.

Management of antenatal hydronephrosis.

Antenatal hydronephrosis (AHN) is the most frequently detected abnormality by prenatal ultrasonography. Differential diagnosis of AHN includes a wide variety of congenital abnormalities of the kidney and urinary tract ranging from mild abnormalities such as transient or isolated AHN to more important ones as high-grade congenital vesicoureteral reflux or ureteropelvic junction obstruction. It is well known that the outcome depends on the underlying etiology. Various grading systems have been proposed for the classification of AHN on prenatal and postnatal ultrasonography. Mild isolated AHN represents up to 80% of cases, is considered to be benign, and majority of them resolve, stabilize, or improve during follow-up. Controversies exist regarding the diagnosis and management of some important and severe causes of AHN such as high-grade vesicoureteral reflux and ureteropelvic junction obstruction. Current approach is becoming increasingly conservative during diagnosis and follow-up of these patients with less imaging and close follow-up. However, there is still no consensus regarding the clinical significance, postnatal evaluation, and management of infants with AHN. The aim of this review is to discuss the controversies and provide an overview on the management of AHN.

Antenatally detected urinary tract dilatation: a 12-15-year follow-up.

BACKGROUND: Antenatally diagnosed urinary tract dilatation (UTD) still burdens healthcare providers and parents. This study was conducted to establish long-term outcome in an unselected group of children with antenatally detected UTD. METHODS: Seventy-one out of 103 children born in 2003-2005 and diagnosed with antenatal UTD agreed to participate in a 12-15-year follow-up including blood and urine samples, a kidney ultrasound exam, and kidney scintigraphy. The records were searched for previous urinary tract infections. RESULTS: Among children with an anteroposterior diameter (APD) ≤ 7 mm and no calyceal, kidney, ureteral, or bladder pathology in the early postnatal period, no one tested had reduced estimated glomerular filtration rate (eGFR), albuminuria, or UTD at the follow-up at a mean age of 13.6 years. One child had kidney damage not affecting kidney function. Among children with postnatal APD > 7 mm and/or kidney, calyceal, ureteral, or bladder pathology, 15% had persistent UTD and 32-39% (depending on the method used) had kidney damage. Major postnatal urinary tract ultrasound abnormalities and a congenital anomalies of the kidney and urinary tract (CAKUT) diagnosis were factors associated with an increased risk for permanent kidney damage (odds ratios 8.9, p = 0.016; and 14.0, p = 0.002, respectively). No one had reduced eGFR. One child (1/71, 1%) had a febrile urinary tract infection after the age of 2. CONCLUSIONS: We conclude that in children with postnatal APD ≤ 7 mm, no calyceal dilatation, normal bladder, ureters, and kidney parenchyma, the outcome is excellent. There is no need for long-term follow-up in these patients.

Incidence, management, and sequelae of ureteric obstruction in women with cervical cancer.

PURPOSE: Hydronephrosis due to ureteric obstruction (UO) is stage-defining at cervical cancer presentation but may occur after primary staging. We aimed to determine the incidence and review the presentation and management of UO in women with cervical cancer attending our center. Particular attention was paid to the evolving role of interventional radiology (IR) in management. METHODS: Women with a new diagnosis of cervical cancer between January 2012 and December 2016 formed the cohort that was retrospectively reviewed from the oncology database and patient records. RESULTS: There were 310 women diagnosed with cervical cancer; 240 were stages I/II and 70 were stages III/IV. Primary treatments were chemoradiotherapy (n = 168; 54.2%), surgery (n = 121; 39.0%), and palliative care alone (n = 21; 6.8%). UO occurred in 74 (23.9%); present at primary staging in 53 (71.6%) and arising after staging in 21 (28.4%). Primary interventions for hydronephrosis were IR (n = 50; 67.6%), cystoscopic stenting (n = 19; 25.7%), bowel urinary conduit construction (n = 2; 2.7%), and none (n = 3; 4.1%). For those who attended IR, the mean number of IR procedures was 2.2, range 1-7. Maximum serum creatinine was 303 µmol/L for women with UO at primary staging compared with 252 µmol/L for UO after staging (P = 0.267). Thirty-eight women experienced substantial morbidity related to UO. Stage-adjusted mortality risk was 2.3 times higher for UO cases compared with those without UO. CONCLUSIONS: UO is associated with substantial morbidity and survival disadvantage in cervical cancer and may present after primary cancer staging. We recommend renal biochemistry during routine follow-up. A majority of cervical cancer-associated UO cases are managed with IR in our center.

Obstructive uropathy and unexpected death.

A 66-year-old man was found dead at his home address. He had a history of poor nutrition with recent episodes of vomiting. At autopsy the decedent was cachexic with a body mass index (BMI) of 16.1. The major findings were of marked prostatomegaly (165 g) with obstruction to urine outflow resulting in dilatation and trabeculation of the bladder and bilateral hydroureteronephrosis. The bladder contained 1.5 l of yellow urine and the kidneys weighed only 109 g on the left and 125 g on the right (N = 140-160 g). Histological examination of the prostate revealed benign nodular hyperplasia. Biochemical analysis of vitreous humor demonstrated a creatinine of 1579 µmol/L (normal 45-90) and a urea of 133.4 mmol/L (normal 2.5-7.1). Despite genitourinary causes of sudden and/or unexpected death being rare in routine forensic practice, this case demonstrates significant underlying obstructive renal disease that resulted in sudden death and that had remained undiagnosed until the time of autopsy.

Time to resolution of isolated antenatal hydronephrosis with anteroposterior diameter ≤ 20 mm.

Data regarding spontaneous resolution of mild hydronephrosis consist of different etiologies, and hence, it is heterogeneous. The aim of this study is to evaluate spontaneous resolution rates and the time to complete resolution of antenatally detected isolated hydronephrosis in patients with renal pelvis antero-posterior diameter (RPAPD) ≤ 20 mm. Retrospective chart review of patients who were admitted to our pediatric nephrology clinic for the evaluation of antenatal hydronephrosis between 2011 and 2017 was conducted. Patients that had hydronephrosis with RPAPD ≤ 20 mm, < SFU (Society for Fetal Urology) grade IV on initial postnatal evaluation, and ≥ 3 months of follow-up with at least two renal ultrasounds (US) were included. Complete resolution of hydronephrosis was regarded as SFU grade 0 with a RPAPD of < 7 mm. Patients with ureteric and lower urinary tract abnormalities were excluded. There were a total of 276 patients who met the inclusion criteria. Median follow-up was 16 months (range 3-96 months). Hydronephrosis completely resolved in 198 patients (71.7%). Surgery was not required in any of the patients; however, nine patients (3.3%) showed progression to higher grades of hydronephrosis or increase in AP diameter. Median time to complete resolution of hydronephrosis was 6 months (range 2-35 months) in our study. Those with AP diameter < 10 mm became normal in median of 5 months, while it took median 11 months for patients with AP diameter 10-20 mm to become normalized (p < 0.001).Conclusion: Isolated antenatal hydronephrosis with RPAPD ≤ 20 mm would spontaneously resolve in 71.7% of the cases. Resolution may be expected to happen in 3 years, while the majority will take place in the first year of life. What is Known: • Antenatal hydronephrosis comprises an important amount of clinical visits. • Spontaneous resolution rates differ for various etiologies. What is New: • Isolated antenatal hydronephrosis with RPAPD ≤ 20 mm completely resolves within 3 years in approximately 72% of the cases. • Resolution can be observed within the first year of life in most of the cases.

Bladder-sparing treatment of nonmetastatic muscle-invasive bladder cancer.

Bladder-sparing therapies for the treatment of nonmetastatic muscle-invasive bladder cancers are included in both American and European guidelines. Numerous treatment approaches have been described, including partial cystectomy, radiation monotherapy, and radical transurethral resection. However, the most oncologically favorable and well-studied regimen employs a multimodal approach that consists of maximal transurethral resection of the bladder tumor followed by concurrent radiosensitizing chemotherapy and radiotherapy. This sequence, referred to as trimodal therapy (TMT), has been evaluated with robust retrospective comparative studies and prospective series, although a randomized trial comparing TMT with radical cystectomy has not been performed. Despite promising reports of 5-year overall survival rates of 50% to 70% in well-selected patients, relatively few patients qualify as ideal candidates for TMT. Specifically, contemporary series exclude patients who have clinical stage T3 disease, multifocal tumors, coexisting carcinoma in situ, or hydronephrosis. Herein, we review all forms of bladder-preserving therapies with an emphasis on TMT, highlighting the rationale of each component, survival outcomes, and future directions.

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.

Metabolic Response in Rabbit Urine to Occurrence and Relief of Unilateral Ureteral Obstruction.

Ureteral obstruction will lead clinically to hydronephrosis, which may further develop into partial or complete loss of kidney function and even cause permanent histological damage. However, there is little knowledge of metabolic responses during the obstructed process and its recoverability. In this study, a complete unilateral ureteral obstruction (CUUO) model was established in the rabbit, and 1H NMR-based metabolomic analysis of urine was used to reveal the metabolic perturbations in rabbits caused by CUUO and the metabolic recovery after the CUUO was relieved. Univariate and multivariate statistical analyses were used to identify metabolic characteristics. The gradually decreased levels of 3-hydroxykynurenine, 3-methylhistidine, creatinine, guanidoacetate, meta- and para-hydroxyphenylacetate, and phenylacetylglycine and the gradually increased levels of acetate, alanine, citrate, glycine, lactate, and methionine in urine could be regarded as potential biomarkers for the occurrence and severity of ureteral obstruction. And the reduced levels of 3-methylhistidine, creatinine, guanidoacetate, hippurate, meta-hydroxyphenylacetate, and methylguanidine and the elevated levels of 2-aminoisobutyrate, acetylcholine, citrate, lactate, lysine, valine, and α-ketoglutarate in urine compared with the obstructed level could characterize the metabolic recovery of ureteral obstruction. Our results depicted the disturbed biochemical pathways involved in ureteral obstruction and demonstrated the practicability of recovering renal functions for the patients with severe hydronephrosis in clinical practice by removing causes for obstruction.

Silencing of SOCS-1 and SOCS-3 suppresses renal interstitial fibrosis by alleviating renal tubular damage in a rat model of hydronephrosis.

Our study was performed to elucidate how SOCS-1/3 silencing suppresses renal interstitial fibrosis (RIF) by alleviating renal tubular damage in rat models affected by hydronephrosis. Male Wistar rats were randomly selected to establish hydronephrosis rat model, after which all rats were classified into normal, model, negative control (NC), siRNA-SOCS-1, siRNA-SOCS-3, and siRNA-SOCS-1 + siRNA-SOCS-3 groups. The levels of urine protein, serum creatinine (Scr), and blood urea nitrogen (BUN) were detected. ELISA was performed to determine levels of cystatin (CysC), ß2-microglobulin (ß2-MG), interleukin (IL)-6, and tumor necrosis factor (TNF)-α. RT-qPCR and Western blotting were used for mRNA and protein expressions of SOCS-1, SOCS-3, α-smooth muscle actin (α-SMA), and transforming Growth Factor (TGF)-ß1. Compared with the normal group, the levels of Scr, BUN, urine protein, NAG, CysC, ß2-MG, IL-6, and TNF-α were increased in other groups, as well as elevated mRNA and protein expressions of SOCS-1, SOCS-3, α-SMA, and TGF-ß1. The siRNA-SOCS-1, siRNA-SOCS-3, and siRNA-SOCS-1 + siRNA-SOCS-3 groups were found with decreased levels of Scr, BUN, urine protein, NAG, CysC, ß2-MG, IL-6, and TNF-α, as well as mRNA and protein expressions of SOCS-1, SOCS-3, α-SMA, and TGF-ß1, including positive rates of SOCS-1 and SOCS-3 proteins in comparison with the model and NC groups. In comparison with the siRNA-SOCS-1 and siRNA-SOCS-3 groups, the siRNA-SOCS-1 + siRNA-SOCS-3 group exhibited decreased levels of Scr, BUN, urine protein, NAG, CysC, ß2-MG, IL-6, and TNF-α. Our study demonstrated that silencing of SOCS-1/3 may suppress RIF by alleviating the renal tubular damage in rat models affected by hydronephrosis.

Urogenital development in Pallister-Hall syndrome is disrupted in a cell-lineage-specific manner by constitutive expression of GLI3 repressor.

Pallister-Hall syndrome (PHS) is a rare disorder caused by mutations in GLI3 that produce a transcriptional repressor (GLI3R). Individuals with PHS present with a variably penetrant variety of urogenital system malformations, including renal aplasia or hypoplasia, hydroureter, hydronephrosis or a common urogenital sinus. The embryologic mechanisms controlled by GLI3R that result in these pathologic phenotypes are undefined. We demonstrate that germline expression of GLI3R causes renal hypoplasia, associated with decreased nephron number, and hydroureter and hydronephrosis, caused by blind-ending ureters. Mice with obligate GLI3R expression also displayed duplication of the ureters that was caused by aberrant common nephric duct patterning and ureteric stalk outgrowth. These developmental abnormalities are associated with suppressed Hedgehog signaling activity in the cloaca and adjacent vesicular mesenchyme. Mice with conditional expression of GLI3R were utilized to identify lineage-specific effects of GLI3R. In the ureteric bud, GLI3R expression decreased branching morphogenesis. In Six2-positive nephrogenic progenitors, GLI3R decreased progenitor cell proliferation reducing the number of nephrogenic precursor structures. Using mutant mice with Gli3R and Gli3 null alleles, we demonstrate that urogenital system patterning and development is controlled by the levels of GLI3R and not by an absence of full-length GLI3. We conclude that the urogenital system phenotypes observed in PHS are caused by GLI3R-dependent perturbations in nephric duct patterning, renal branching morphogenesis and nephrogenic progenitor self-renewal.

Diagnostic Value of Anteroposterior Diameter of Renal Pelvis for Predicting Postnatal Surgery: A Systematic Review and Meta-Analysis.

PURPOSE: We assessed the diagnostic value of anteroposterior diameter of the fetal renal pelvis in predicting postnatal surgery. MATERIALS AND METHODS: PubMed®, Embase® and Cochrane Library databases were searched for articles comparing patients who underwent surgery or conservative therapy with 15 mm anteroposterior diameter as a cutoff value. Data on sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic OR and area under the summary ROC curve were used to evaluate the diagnostic value of anteroposterior diameter of the fetal renal pelvis in predicting postnatal surgery. RESULTS: Five studies involving a total of 1,159 patients met the inclusion criteria. The summary sensitivity and specificity were 0.81 (95% CI 0.60 to 0.92) and 0.78 (95% CI 0.68 to 0.86), respectively. Positive and negative likelihood ratios of anteroposterior diameter were 3.73 (95% CI 2.75 to 5.06) and 0.24 (95% CI 0.11 to 0.52), respectively. Diagnostic OR of anteroposterior diameter for predicting postnatal surgery was 13.33 (95% CI 6.61 to 26.89) and area under the summary ROC curve was 0.85 (95% CI 0.82 to 0.88). Subgroup analysis suggested postnatal anteroposterior diameter was associated with higher diagnostic OR compared to prenatal anteroposterior diameter for predicting postnatal surgery (ratio between prenatal and postnatal anteroposterior diameter 0.27, 95% CI 0.09 to 0.86, p = 0.026). CONCLUSIONS: Using 15 mm anteroposterior diameter of the fetal renal pelvis as a cutoff showed moderate diagnostic value for predicting postnatal surgery.

Society for Fetal Urology Classification vs Urinary Tract Dilation Grading System for Prognostication in Prenatal Hydronephrosis: A Time to Resolution Analysis.

PURPOSE: The Urinary Tract Dilation grading system for prenatal hydronephrosis was introduced to address potential shortcomings of the Society for Fetal Urology classification. Hydronephrosis resolution is an important patient outcome and is frequently discussed during family counseling. We compared these 2 grading systems and their ability to predict time to hydronephrosis resolution. MATERIALS AND METHODS: We prospectively screened 855 patients with prenatal hydronephrosis due to ureteropelvic junction obstruction-like hydronephrosis, nonrefluxing primary megaureter or vesicoureteral reflux between 2009 and 2015. Of the patients 454 were excluded due to surgery, late referral, absence of postnatal dilatation or presence of other anomalies, resulting in 401 eligible patients (of whom 81% were male) to be included for analyses. Hydronephrosis grades collected at baseline and last followup were compared to identify resolution trends through time. Hydronephrosis resolution was defined as renal pelvis anteroposterior diameter 10 mm or less at last followup. Time to resolution was analyzed using Cox proportion regression. RESULTS: Of 401 patients 328 (82%) had resolution during a mean ± SD followup of 24 ± 18 months (maximum 107). Cumulative resolution rate at 3 years was 98% for Society for Fetal Urology grade I hydronephrosis, 87% for grade II, 76% for grade III and 57% for grade IV. The 3-year hydronephrosis resolution rate was 90% for Urinary Tract Dilation postnatal grade 1 (low risk), 81% for grade 2 (intermediate risk) and 71% for grade 3 (high risk). CONCLUSIONS: Patients with distinctive baseline hydronephrosis grades (classified by Society for Fetal Urology or Urinary Tract Dilation system) had significantly different resolution times for hydronephrosis (p <0.001). Counseling families regarding time to resolution of prenatal hydronephrosis should remain the same whether using Society for Fetal Urology or Urinary Tract Dilation grading system.

Urinary bladder hypertrophy characteristic of male ROMK Bartter's mice does not occur in female mice.

The renal outer medullary potassium channel (ROMK; Kir1.1) plays an important role in Na+ and K+ homeostasis. ROMK knockout (KO) mice show a similar phenotype to Bartter's syndrome of salt wasting and dehydration due to reduced Na-2Cl-K-cotransporter activity but not in ROMK1 KO mice. ROMK KO mice also show hydronephrosis; however, the mechanism of this phenotype has not been understood. We have previously demonstrated a gender-sex difference in hydronephrosis and PGE2 production in ROMK KO mice. In this study we compared the gender-sex difference in bladder hypertrophy and hydronephrosis in ROMK KO mice. The bladder weight, bladder capacity, and the thickness of urothelium in male ROMK KO showed average increased two to approximately fourfold greater than wild-type (WT) mice, but there was no difference in either female or ROMK1 KO mice. The thickness of the urothelium was 648.8 ± 33.2 µm vs. 302.7 ± 16.5 µm ( P < 0.001) and the detrusor muscle 1,940.7 ± 98.9 µm vs. 1,308.2 ± 102.1 µm ( P = 0.013), respectively, in 12-mo male ROMK KO mice compared with the same age WT mice. Western blotting detected ROMK expression at 45~48 kDa, and both ROMK1 and ROMK2 mRNA were detected by quantitative PCR in the bladder. Immunofluorescence staining showed ROMK stained in the bladder, ureter, and urethra in WT but not in KO. In addition, there was a correlation between the severity of hydronephrosis and the bladder weight in male but not in female ROMK KO mice. In conclusion, ROMK expressed in the urinary tract at both protein and mRNA levels; significant enlargement and hypertrophy of the bladder may contribute to hydronephrosis in male ROMK KO mice.

Changes in cell fate determine the regenerative and functional capacity of the developing kidney before and after release of obstruction.

Congenital obstructive nephropathy is a major cause of chronic kidney disease (CKD) in children. The contribution of changes in the identity of renal cells to the pathology of obstructive nephropathy is poorly understood. Using a partial unilateral ureteral obstruction (pUUO) model in genetically modified neonatal mice, we traced the fate of cells derived from the renal stroma, cap mesenchyme, ureteric bud (UB) epithelium, and podocytes using Foxd1Cre, Six2Cre, HoxB7Cre, and Podocyte.Cre mice respectively, crossed with double fluorescent reporter (membrane-targetted tandem dimer Tomato (mT)/membrane-targetted GFP (mG)) mice. Persistent obstruction leads to a significant loss of tubular epithelium, rarefaction of the renal vasculature, and decreased renal blood flow (RBF). In addition, Forkhead Box D1 (Foxd1)-derived pericytes significantly expanded in the interstitial space, acquiring a myofibroblast phenotype. Degeneration of Sine Oculis Homeobox Homolog 2 (Six2) and HoxB7-derived cells resulted in significant loss of glomeruli, nephron tubules, and collecting ducts. Surgical release of obstruction resulted in striking regeneration of tubules, arterioles, interstitium accompanied by an increase in blood flow to the level of sham animals. Contralateral kidneys with remarkable compensatory response to kidney injury showed an increase in density of arteriolar branches. Deciphering the mechanisms involved in kidney repair and regeneration post relief of obstruction has potential therapeutic implications for infants and children and the growing number of adults suffering from CKD.

Chronically Elevated Levels of Short-Chain Fatty Acids Induce T Cell-Mediated Ureteritis and Hydronephrosis.

Short-chain fatty acids (SCFAs) are major products of gut microbial fermentation and profoundly affect host health and disease. SCFAs generate IL-10(+) regulatory T cells, which may promote immune tolerance. However, SCFAs can also induce Th1 and Th17 cells upon immunological challenges and, therefore, also have the potential to induce inflammatory responses. Because of the seemingly paradoxical SCFA activities in regulating T cells, we investigated, in depth, the impact of elevated SCFA levels on T cells and tissue inflammation in mice. Orally administered SCFAs induced effector (Th1 and Th17) and regulatory T cells in ureter and kidney tissues, and they induced T cell-mediated ureteritis, leading to kidney hydronephrosis (hereafter called acetate-induced renal disease, or C2RD). Kidney hydronephrosis in C2RD was caused by ureteral obstruction, which was, in turn, induced by SCFA-induced inflammation in the ureteropelvic junction and proximal ureter. Oral administration of all major SCFAs, such as acetate, propionate, and butyrate, induced the disease. We found that C2RD development is dependent on mammalian target of rapamycin activation, T cell-derived inflammatory cytokines such as IFN-γ and IL-17, and gut microbiota. Young or male animals were more susceptible than old or female animals, respectively. However, SCFA receptor (GPR41 or GPR43) deficiency did not affect C2RD development. Thus, SCFAs, when systemically administered at levels higher than physiological levels, cause dysregulated T cell responses and tissue inflammation in the renal system. The results provide insights into the immunological and pathological effects of chronically elevated SCFAs.