Genome-wide identification of disease-causing copy number variations in 450 individuals with anorectal malformations.

Anorectal malformations (ARM) represent a spectrum of rare malformations originating from a perturbated development of the embryonic hindgut. Approximately 60% occur as a part of a defined genetic syndrome or within the spectrum of additional congenital anomalies. Rare copy number variations (CNVs) have been associated with both syndromic and non-syndromic forms. The present study represents the largest study to date to explore the contribution of CNVs to the expression of ARMs. SNP-array-based molecular karyotyping was applied in 450 individuals with ARM and 4392 healthy controls. CNVs were identified from raw intensity data using PennCNV. Overlapping CNVs between cases and controls were discarded. Remaining CNVs were filtered using a stringent filter algorithm of nine filter steps. Prioritized CNVs were confirmed using qPCR. Filtering prioritized and qPCR confirmed four microscopic chromosomal anomalies and nine submicroscopic CNVs comprising seven microdeletions (del2p13.2, del4p16.2, del7q31.33, del9p24.1, del16q12.1, del18q32, del22q11.21) and two microduplications (dup2p13.2, dup17q12) in 14 individuals (12 singletons and one affected sib-pair). Within these CNVs, based on their embryonic expression data and function, we suggest FOXK2, LPP, and SALL3 as putative candidate genes. Overall, our CNV analysis identified putative microscopic and submicroscopic chromosomal rearrangements in 3% of cases. Functional characterization and re-sequencing of suggested candidate genes is warranted.

A genome-wide association study with tissue transcriptomics identifies genetic drivers for classic bladder exstrophy.

Classic bladder exstrophy represents the most severe end of all human congenital anomalies of the kidney and urinary tract and is associated with bladder cancer susceptibility. Previous genetic studies identified one locus to be involved in classic bladder exstrophy, but were limited to a restrict number of cohort. Here we show the largest classic bladder exstrophy genome-wide association analysis to date where we identify eight genome-wide significant loci, seven of which are novel. In these regions reside ten coding and four non-coding genes. Among the coding genes is EFNA1, strongly expressed in mouse embryonic genital tubercle, urethra, and primitive bladder. Re-sequence of EFNA1 in the investigated classic bladder exstrophy cohort of our study displays an enrichment of rare protein altering variants. We show that all coding genes are expressed and/or significantly regulated in both mouse and human embryonic developmental bladder stages. Furthermore, nine of the coding genes residing in the regions of genome-wide significance are differentially expressed in bladder cancers. Our data suggest genetic drivers for classic bladder exstrophy, as well as a possible role for these drivers to relevant bladder cancer susceptibility.

Re-sequencing of candidate genes FOXF1, HSPA6, HAAO, and KYNU in 522 individuals with VATER/VACTERL, VACTER/VACTERL-like association, and isolated anorectal malformation.

BACKGROUND: The acronym VATER/VACTERL association describes the combination of at least three component features (CFs): vertebral defects (V), anorectal malformations (ARM) (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). Individuals presenting two CFs have been termed VATER/VACTERL-like. Recently, FOXF1, HSPA6, HAAO, KYNU, TRAP1, and ZIC3 have been proposed as candidate genes for VATER/VACTERL, VATER/VACTERL-like, and ARM. Re-sequencing studies identified disease-causing variants in TRAP1 and ZIC3, the contribution of other genes was not independently investigated. One affected variant carrier in FOXF1 was previously identified. Here we re-sequenced FOXF1, HSPA6, HAAO, and KYNU in 522 affected individuals. METHODS: Using molecular inversion probe (MIP) technology, re-sequencing was performed in 63 individuals with VATER/VACTERL association, 313 with VATER/VACTERL-like association, and 146 with ARM. All individuals were of European ethnicity. Variant filtering considered variants with a minor allele frequency (MAF) ≤0.01 for putative recessive disease-genes HSPA6, HAAO, and KYNU. For the putative dominant disease-gene FOXF1 we considered variants with a MAF ≤0.0001. In silico prediction tools were used for further prioritization. RESULTS: Only two variants in FOXF1 in two independently affected individuals [c.443G>T, p.(Cys148Phe); c.850T>C, p.(Tyr284His)] passed our filter criteria. One individual presented with ARM, the second presented with TE and C comprising atrial and ventricular septal defects. Sanger sequencing confirmed both variants but also their inheritance from the healthy mother. CONCLUSION: Our analysis suggests that FOXF1, HSPA6, HAAO and KYNU do not play a major role in the formation of VACTER/VACTERL phenotypes or ARM.

Increased Incidence of Perforated Appendicitis in Children During COVID-19 Pandemic in a Bavarian Multi-Center Study.

Introduction: Since early 2020 the COVID-19 pandemic and statutory preventive reorganization of treatment capacities with cancellation of elective surgery as well as curfew regulations led to vastly decreased utilization of primary health care. Materials and Methods: To assess whether there are negative effects on pediatric acute care in Bavaria during the spring 2020 lockdown a state-wide retrospective multi-center study was performed to analyze the rate of perforated appendicitis during lockdown. Children who have been operated on during the corresponding period in 2018/19 served as control group. Results: Overall, 514 patients (292 boys, 222 girls) were included (2020: 176 patients; 2019: 181 patients; 2018: 157 patients). Median age was 11.2 years. Four hundred thirty-nine patients (85.4%) underwent laparoscopic surgery, 69 (13.4%) open surgery and 1.2% underwent conversion from laparoscopic to open surgery. In 2020 a perforation rate of 27.8% (49/176 patients) was found, in 2018-2019 perforation rate was 20.7% (70/338 patients, p = 0.0359, Cochran-Mantel-Haenszel-Test). Subgroup analysis showed that in younger patients (≤ 11.2 years), in 2020 perforation rate was significantly higher with 37.6% (32/85 patients), while 22.2% (39/176) in 2018/2019 (p = 0.014, Fisher's exact test).In boys perforation rate was significantly higher in 2020 with 35.0% (35/100 patients) compared to 21.4% in 2018-2019 (p = 0.0165, Fisher's exact test). Conclusion: During the period of curfew regulations in Bavaria the rate of perforated appendicitis in childhood increased significantly, especially in younger children and boys. Potentially this has to be attributed to delayed presentation to pediatric surgery care. Because of potential long-term sequelae of perforated appendicitis these adverse effects during curfew have to be taken into account for future political decision making to ensure reasonable patient care and avoid collateral damage in near-future or on-going pandemic situations.

Congenital Y-urethra - A diagnostic and therapeutic challenge.

BACKGROUND: For the Y-subtype of urethral duplications expression and nomenclature vary, as treatment recommendations do. OBJECTIVE: To raise awareness of the variety and variable terminology of Y-type duplication of the urethra, and to discuss the diagnostic work-up in light of options for or against surgical reconstruction. MATERIALS AND METHODS: Five patients with congenital Y-urethra were treated in four institutions within 15 years (2004-2019). While patients were managed in our respective institution with some exchange of experience, all available data were shared and evaluated for this review. RESULTS: The age at initial presentation was 1 day-6 months. In three patients the Y-urethra was found together with an anorectal malformation (ARM). With the focus on reconstruction rather than suprapubic diversion the orthotopic urethra was restored in the majority of patients using either single-step or staged approaches while the accessory urethral limb was incorporated. This was successful despite additional procedures aiming at ARM reconstruction. The patients void spontaneously and do control urine and bowels. One patient underwent kidney transplantation as a consequence of associated renal anomalies while reconstructive attempts regarding his urethral anomaly failed. In two patients, uncertainty in recognizing the pathology delayed a purposive treatment. DISCUSSION: For this rare anomaly the terminology in the literature merges and suggestions for the treatment differ. Success in four out five patients supports an approach which makes use of the accessory ventral track to restore the orthotopic urethra. Since some patients present as a neonatal emergency with concomitant problems such as ARM, a basic understanding of the variable pathology is required. CONCLUSION: The cases of Y-urethra reported herein demonstrate that correct allocation at the initial presentation or at least prior to first surgical steps will preserve the chance for physiologic micturition and urinary continence. Timing of surgery has to be done in the context of associated malformations and is not an emergency as long as proper bladder drainage is ensured. However, relocation of the accessory track requires several procedures bearing risks of complications short and long-term. This may be an argument to consider any therapeutic strategy against other options such as postponed treatment or permanent suprapubic diversion. Evidence-based guidelines are lacking.

Acute urinary retention in children.

BACKGROUND: Acute urinary retention is a common emergency in adult patients, foremost in older men. In childhood urinary retention is a rare entity with only sparse literature on the etiology. OBJECTIVE: To assess the etiology and treatment of acute urinary retention in the pediatric population and assess age and sex distribution. STUDY DESIGN: A retrospective analysis of all patients admitted to our emergency department with acute urinary retention between 2005 and 2019 was performed. Exclusion criteria were newborns (because of physiologic postnatal oliguria) and postoperative urinary retention during the same hospital stay. RESULTS: 113 children with acute urinary retention (ICD: R33) meeting the above criteria were identified. 16 Patients were excluded because of incomplete medical charts. 97 children were included into the study (age 0.5-18.3 years, mean age 5.3 years). 89 patients had one episode, 8 patients two episodes. A peak around the third year of age was observed. Sex ratio showed a 2:1 male to female distribution. Most common etiology was balanoposthitis (15.5%) and acute constipation/fecal impaction (15.5%). Traumatic urinary retention was found in 11.4% of the cases. Urinary tract infection were found 7.2%. No underlying reason could be found in 12.4% (idiopathic urinary retention). Other causes included febrile non-urinary infection (8.2%), subvesical obstruction (4.1%), vulvovaginitis (3.1%) and urethritis (2.1%). In 50% of the cases of urinary retention under 1 year of age (2 out of 4) an underlying tumor (rhabdomyosarcoma, sacral teratoma) was identified. DISCUSSION: Age and sex distribution were similar to previously published series; however, this study shows a marked difference concerning the etiology: e. g. we identified a significantly higher proportion of functional disorders as a reason for acute urinary retention in childhood. It is hypothesized that this is partly because previously published studies originate from areas (USA, Israel, Iran) with different socio-demographic and cultural background. CONCLUSION: AUR in children is a rare condition with very heterogeneous causes. Although the majority of cases exhibit mild underlying conditions, serious reasons, such as malignant diseases especially in the first year of life, must be excluded. AUR relief without catheterization is a child-friendly approach in cases of mild inflammatory or functional disorders and can help to minimize traumatization.

SLC20A1 Is Involved in Urinary Tract and Urorectal Development.

Previous studies in developing Xenopus and zebrafish reported that the phosphate transporter slc20a1a is expressed in pronephric kidneys. The recent identification of SLC20A1 as a monoallelic candidate gene for cloacal exstrophy further suggests its involvement in the urinary tract and urorectal development. However, little is known of the functional role of SLC20A1 in urinary tract development. Here, we investigated this using morpholino oligonucleotide knockdown of the zebrafish ortholog slc20a1a. This caused kidney cysts and malformations of the cloaca. Moreover, in morphants we demonstrated dysfunctional voiding and hindgut opening defects mimicking imperforate anus in human cloacal exstrophy. Furthermore, we performed immunohistochemistry of an unaffected 6-week-old human embryo and detected SLC20A1 in the urinary tract and the abdominal midline, structures implicated in the pathogenesis of cloacal exstrophy. Additionally, we resequenced SLC20A1 in 690 individuals with bladder exstrophy-epispadias complex (BEEC) including 84 individuals with cloacal exstrophy. We identified two additional monoallelic de novo variants. One was identified in a case-parent trio with classic bladder exstrophy, and one additional novel de novo variant was detected in an affected mother who transmitted this variant to her affected son. To study the potential cellular impact of SLC20A1 variants, we expressed them in HEK293 cells. Here, phosphate transport was not compromised, suggesting that it is not a disease mechanism. However, there was a tendency for lower levels of cleaved caspase-3, perhaps implicating apoptosis pathways in the disease. Our results suggest SLC20A1 is involved in urinary tract and urorectal development and implicate SLC20A1 as a disease-gene for BEEC.

Treatment Strategies and Outcome of the Exstrophy-Epispadias Complex in Germany: Data From the German CURE-Net.

Introduction: To evaluate the impact of reconstructive strategies and post-operative management on short- and long-term surgical outcome and complications of classical bladder exstrophy (CBE) patients' comprehensive data of the multicenter German-wide Network for Congenital Uro-Rectal malformations (CURE-Net) were analyzed. Methods: Descriptive analyses were performed between 34 prospectively collected CBE patients born since 2009, median 3 months old [interquartile range (IQR), 2-4 months], and 113 cross-sectional patients, median 12 years old (IQR, 6-21 years). Results: The majority of included individuals were males (67%). Sixty-eight percent of the prospectively observed and 53% of the cross-sectional patients were reconstructed using a staged approach (p = 0.17). Although prospectively observed patients were operated on at a younger age, the post-operative management did not significantly change in the years before and after 2009. Solely, in prospectively observed patients, peridural catheters were used significantly more often (p = 0.017). Blood transfusions were significantly more frequent in males (p = 0.002). Only half of all CBE individuals underwent inguinal hernia repair. Cross-sectional patients after single-stage reconstructions showed more direct post-operative complications such as upper urinary tract dilatations (p = 0.0021) or urinary tract infections (p = 0.023), but not more frequent renal function impairment compared to patients after the staged approach (p = 0.42). Continence outcomes were not significantly different between the concepts (p = 0.51). Self-reported continence data showed that the majority of the included CBE patients was intermittent or continuous incontinent. Furthermore, subsequent consecutive augmentations and catheterizable stomata did not significantly differ between the two operative approaches. Urinary diversions were only reported after the staged concept. Conclusions: In this German multicenter study, a trend toward the staged concept was observed. While single-stage approaches tended to have initially more complications such as renal dilatation or urinary tract infections, additional surgery such as augmentations and stomata appeared to be similar after staged and single-stage reconstructions in the long term.

[Primary obstructive megaureter: a domain of conservative treatment]. / Der Primär Obstruktive Megaureter (POM) ­ Eine Domäne konservativer Therapie.

The term "megaureter" is an entirely descriptive designation for a number of different entities. It is crucial to distinguish between primary and secondary forms of megaureter and between obstructive and/or refluxive forms. In the majority of cases, there is a primary obstruction in the terminal ureterovesical segment. The treatment of primary obstructive megaureter has changed fundamentally over the last 3 decades. Whereas ureteral reimplantation was the treatment of choice in the past, conservative treatment is now preferred in 85 to 90 % of patients. With the advent of endoscopic balloon dilatation, a modern, minimally-invasive treatment option has become an alternative to ureteral reimplantation in selected patients. However, due to the possibility of postoperative VUR (vesicoureteral reflux), it is necessary to emphasize that this option should not weaken the generally strict indication for surgical treatment of primary obstructive megaureter.

Augmentation Cystoplasty of Diseased Porcine Bladders with Bi-Layer Silk Fibroin Grafts.

IMPACT STATEMENT: The search for an ideal "off-the-shelf" biomaterial for augmentation cystoplasty remains elusive and current scaffold configurations are hampered by mechanical and biocompatibility restrictions. In addition, preclinical evaluations of potential scaffold designs for bladder repair are limited by the lack of tractable large animal models of obstructive bladder disease that can mimic clinical pathology. The results of this study describe a novel, minimally invasive, porcine model of partial bladder outlet obstruction that simulates clinically relevant phenotypes. Utilizing this model, we demonstrate that acellular, bi-layer silk fibroin grafts can support the formation of vascularized, innervated bladder tissues with functional properties.

Tissue engineering in pediatric urology - a critical appraisal.

Tissue engineering is defined as the combination of biomaterials and bioengineering principles together with cell transplantation or directed growth of host cells to develop a biological replacement tissue or organ that can be a substitute for normal tissue both in structure and function. Despite early promising preclinical studies, clinical translation of tissue engineering in pediatric urology into humans has been unsuccessful both for cell-seeded and acellular scaffolds. This can be ascribed to various factors, including the use of only non-diseased models that inaccurately describe the structural and functional modifications of diseased tissue. The paper addresses potential future strategies to overcome the limitations experienced in clinical applications so far. This includes the use of stem cells of various origins (mesenchymal stem cells, hematopoietic stem/progenitor cells, urine-derived stem cells, and progenitor cells of the urothelium) as well as the need for a deeper understanding of signaling pathways and directing tissue ingrowth and differentiation through the concept of dynamic reciprocity. The development of smart scaffolds that release trophic factors in a set and timely manner will probably improve regeneration. Modulation of innate immune response as a major contributor to tissue regeneration outcome is also addressed. It is unlikely that only one of these strategies alone will lead to clinically applicable tissue engineering strategies in pediatric urology. In the meanwhile, the fundamental new insights into regenerative processes already obtained in the attempts of tissue engineering of the lower urogenital tract remain our greatest gain.

Bilayer silk fibroin grafts support functional oesophageal repair in a rodent model of caustic injury.

Surgical repair of caustic oesophageal injuries with autologous gastrointestinal segments is often associated with dysmotility, dysphagia and donor site morbidity, and therefore alternative graft options are needed. Bilayer silk fibroin (BLSF) scaffolds were assessed for their ability to support functional restoration of damaged oesophageal tissues in a rat model of onlay oesophagoplasty. Transient exposure of isolated oesophageal segments with 40% NaOH led to corrosive oesophagitis and a 91% reduction in the luminal cross-sectional area of damaged sites. Oesophageal repair with BLSF matrices was performed in injured rats (n = 27) as well as a nondiseased cohort (n = 12) for up to 2 months after implantation. Both implant groups exhibited >80% survival rates, displayed similar degrees of weight gain, and were capable of solid food consumption following a 3-day liquid diet. End-point µ-computed tomography of repaired sites demonstrated a 4.5-fold increase in luminal cross-sectional area over baseline injury levels. Reconstructed oesophageal conduits from damaged and nondiseased animals produced comparable contractile responses to KCl and electric field stimulation while isoproterenol generated similar tissue relaxation responses. Histological and immunohistochemical evaluations of neotissues from both implant groups showed formation of a stratified, squamous epithelium with robust cytokeratin expression as well as skeletal and smooth muscle layers positive for contractile protein expression. In addition, synaptophysin positive neuronal junctions and vessels lined with CD31 positive endothelial cells were also observed at graft sites in each setting. These results provide preclinical validation for the use of BLSF scaffolds in reconstructive strategies for oesophageal repair following caustic injury.

Bi-layer silk fibroin grafts support functional tissue regeneration in a porcine model of onlay esophagoplasty.

Partial circumferential, full thickness defects of the esophagus can occur as a result of organ perforation or tumour resection, or during surgical reconstruction of strictured segments. Complications associated with autologous tissue flaps conventionally utilized for defect repair necessitate the development of new graft options. In this study, bi-layer silk fibroin (BLSF) scaffolds were investigated for their potential to support functional restoration of partial circumferential defects in a porcine model of esophageal repair. Onlay thoracic esophagoplasty with BLSF matrices (~3 x 1.5 cm) was performed in adult swine (N = 6) for 3 months of implantation. All animals receiving BLSF grafts survived with no complications and were capable of solid food consumption. Radiographic esophagrams revealed preservation of organ continuity with no evidence of contrast extravasation or strictures. Fluoroscopic analysis demonstrated peristaltic contractions. Ex vivo tissue bath studies displayed contractile responses to carbachol, electric field stimulation, and KCl while isoproterenol produced tissue relaxation. Histological and immunohistochemical evaluations of neotissues showed a stratified, squamous epithelium, a muscularis mucosa composed of smooth muscle bundles, and a muscularis externa organized into circular and longitudinal layers, with a mix of striated skeletal muscle fascicles interspersed with smooth muscle. De novo innervation and vascularization were observed throughout the graft sites and consisted of synaptophysin-positive neuronal boutons and vessels lined with CD31-positive endothelial cells. The results of this study demonstrate that BLSF scaffolds can facilitate constructive remodeling of partial circumferential, full thickness esophageal defects in a large animal model. Copyright © 2017 John Wiley & Sons, Ltd.

Mode of Surgical Injury Influences the Source of Urothelial Progenitors during Bladder Defect Repair.

The bladder urothelium functions as a urine-blood barrier and consists of basal, intermediate, and superficial cell populations. Reconstructive procedures such as augmentation cystoplasty and focal mucosal resection involve localized surgical damage to the bladder wall whereby focal segments of the urothelium and underlying submucosa are respectively removed or replaced and regeneration ensues. We demonstrate using lineage-tracing systems that urothelial regeneration following augmentation cystoplasty with acellular grafts exclusively depends on host keratin 5-expressing basal cells to repopulate all lineages of the de novo urothelium at implant sites. Conversely, repair of focal mucosal defects not only employs this mechanism, but in parallel host intermediate cell daughters expressing uroplakin 2 give rise to themselves and are also contributors to superficial cells in neotissues. These results highlight the diversity of urothelial regenerative responses to surgical injury and may lead to advancements in bladder tissue engineering approaches.