The importance of animal specificity in animal experimentation, part II: Physiological challenges and opportunities in relation to pediatric urology

When performing animal experimentation in Pediatric Urology studies, it is important to be aware of physiological differences between species and to understand when relevant disease models are available. Diseased animal models may be more relevant in many cases, rather than performing studies in healthy and normally developed animals. For example, they may be more appropriate for the study of congenital malformations, to investigate the secondary effects of prenatal urinary obstruction, to study the effect of prenatal exposure to endogenous or exogenous factors which may lead to disease, or in testing bioengineered structures. In this short educational article, we aim to describe some disease models that have been used to simulate human pathologies and how, if properly designed, these studies can lead to important new knowledge for human translation. In addition, we also highlight the importance of formulating a research question(s) before deciding on the animal experimental model and species to choose.

The importance of animal specificity in animal experimentation, part I: Anatomy in relation to pediatric urology

Why and when is animal experimentation relevant? The answer to this question depends on the research question. In this short educational article we aim to raise awareness of the importance of formulating a very specific research question before choosing an animal species. An awareness of anatomical and physiological differences vis-a-vis similarities between species, will increase the potential for obtaining data that is relevant for translation to human conditions.

A perioperative layered autologous tissue expansion graft for hollow organ repair

Tissue engineering has not been widely adopted in clinical settings for several reasons, including technical challenges, high costs, and regulatory complexity. Here, we introduce the Perioperative Layered Autologous Tissue Expansion graft (PLATE graft), a composite biomaterial and collagen-reinforced construct with autologous epithelium on one side and smooth muscle tissue on the other. Designed to mimic the structure and function of natural hollow organs, the PLATE graft is unique in that it can be produced in a standard operating theatre and is cost-effective. In this proof-of-principle study, we test its regenerative performance in eight different organs, present biomechanical and permeability tests, and finally explore its in vivo performance in live rabbits.

Fetal biomarkers for lower urinary tract obstruction secondary to posterior urethral valves

Today, prenatal diagnosis of congenital urogenital malformations is mostly dependent on anatomical variations found on imaging. However, these findings can mislead us in telling us when to intervene, and about post-natal prognosis. Since many findings are dependent on multiple assessments, delayed diagnosis can occur, leading to less optimal outcomes compared to early intervention. Analyses of fetal urinary biomarkers have been proposed as a method of finding biological changes that are predictive for diagnosis and prognosis in fetuses at risk of kidney disease. We interviewed a group of researchers that have demonstrated that by combining multiple omics traits extracted from fetal urine, the biological variability found in single omics data can be circumvented. By analyzing multiple fetal urine peptides and metabolites at single time point, the prognostic power of postnatal renal outcome in fetuses with lower urinary tract obstruction is significantly increased. In this interview, we inquired about the technical aspects of the tests, challenges, and limitations the research group have come across, and how they envision the future for multi-omics fetal analysis in the clinic.

Advancing autologous urothelial micrografting and composite tubular grafts for future single-staged urogenital reconstructions

Urogenital reconstructive surgery can be impeded by lack of tissue. Further developments within the discipline of tissue engineering may be part of a solution to improve clinical outcomes. In this study, we aimed to design an accessible and easily assembled tubular graft with autologous tissue, which could be constructed and implanted as a single-staged surgical procedure within the premises of an ordinary operating room. The ultimate goals would be to optimize current treatment-options for long-term urinary diversion. Therefore, we evaluated the optimal composition of a collagen-based scaffold with urothelial micrografts in vitro, and followingly implanted the construct in vivo as a bladder conduit. The scaffold was evaluated in relation to cell regeneration, permeability, and biomechanical properties. After establishing an optimized scaffold in vitro, consisting of high-density collagen with submerged autologous micrografts and reinforced with a mesh and stent, the construct was successfully implanted in an in vivo minipig model. The construct assemblance and surgical implantation proved feasible within the timeframe of a routine surgical intervention, and the animal quickly recovered postoperatively. Three weeks post-implantation, the conduit demonstrated good host-integration with a multilayered luminal urothelium. Our findings have encouraged us to support its use in more extensive preclinical large-animal studies.

Insights into cellular behavior and micromolecular communication in urothelial micrografts

Autologous micrografting is a technique currently applied within skin wound healing, however, the potential use for surgical correction of other organs with epithelial lining, including the urinary bladder, remains largely unexplored. Currently, little is known about the micrograft expansion potential and the micromolecular events that occur in micrografted urothelial cells. In this study, we aimed to evaluate the proliferative potential of different porcine urothelial micrograft sizes in vitro, and, furthermore, to explore how urothelial micrografts communicate and which microcellular events are triggered. We demonstrated that increased tissue fragmentation subsequently potentiated the yield of proliferative cells and the cellular expansion potential, which confirms, that the micrografting principles of skin epithelium also apply to uroepithelium. Furthermore, we targeted the expression of the extracellular signal-regulated kinase (ERK) pathway and demonstrated that ERK activation occurred predominately at the micrograft borders and that ERK inhibition led to decreased urothelial migration and proliferation. Finally, we successfully isolated extracellular vesicles from the micrograft culture medium and evaluated their contents and relevance within various enriched biological processes. Our findings substantiate the potential of applying urothelial micrografting in future tissue-engineering models for reconstructive urological surgery, and, furthermore, highlights certain mechanisms as potential targets for future wound healing treatments.

Precision medicine and rare diseases in pediatric urology

Precision Medicine holds promise for helping us manage specific phenotypes of common diseases. For rare diseases such as hypospadias, DSD, and pediatric solid tumors, it can also reveal underlying risk factors and pathogenesis. Professors Ann Nordgren and Anna Lindstrand share their experiences in the development and ongoing initiatives of the Swedish national project on Precision Medicine and how it could change the care of pediatric urology patients.

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Paediatric urology is a subspeciality of urology, with close links to paediatric surgery. This review concludes that a holistic life-long approach to management in highly specialised treatment centres is essential for many of the rare congenital conditions - in Denmark, paediatric urology is centralised to two institutions: Rigshospitalet in Copenhagen and Aarhus University Hospital in Aarhus. Other than performing basic urology in paediatric patients, both centres specialise in complex and rare urological conditions and thus have been accredited by the European Reference Network on rare diseases through the eUrogen collaboration. Patient populations have covered span from prenatal to childhood, transition and for some anomalies, even into adulthood.

Copy number variants suggest different molecular pathways for the pathogenesis of bladder exstrophy

Bladder exstrophy is a rare congenital malformation leaving the urinary bladder open in the midline of the abdomen at birth. There is a clear genetic background with chromosome aberrations, but so far, no consistent findings apart from 22q11-duplications detected in about 2%-3% of all patients. Some genes are implicated like the LZTR1, ISL1, CELSR3, and the WNT3 genes, but most are not explained molecularly. We have performed chromosomal microarray analysis on a cohort of 140 persons born with bladder exstrophy to look for submicroscopic chromosomal deletions and duplications. Pathogenic or possibly pathogenic microdeletions or duplications were found in 16 patients (11.4%) and further 9 with unknown significance. Two findings were in regions linked to known syndromes, two findings involved the same gene (MCC), and all other findings were unique. A closer analysis suggests a few gene networks that are involved in the pathogenesis of bladder exstrophy; the WNT-signaling pathway, the chromosome 22q11 region, the RIT2 and POU families, and involvement of the Golgi apparatus. Bladder exstrophy is a rare malformation and is reported to be associated with several chromosome aberrations. Our data suggest involvement of some specific molecular pathways.

A qualitative content analysis of the experience of hypospadias care: The importance of owning your own narrative

OBJECTIVES

There is a lack of studies on men's individual experiences of living with hypospadias. We aimed to explore the personal experiences of having hypospadias in relation to healthcare and surgery.

SUBJECTS AND METHODS

Purposive sampling was used to include men (aged 18 and over) with hypospadias representing different phenotypes (from distal to proximal) and ages in order to maximise the variation and richness of our data. Seventeen informants, aged 20-49, were included in the study. In-depth semi-structured interviews were conducted between 2019 and 2021. Inductive qualitative content analysis was used to analyse the data.

RESULTS

We identified three categories: (1) Having surgery, which comprised the decision to operate, the experience of having surgery, and the outcomes of surgery; (2) Going to the doctor, which focused on follow-up care, re-entering care in adolescence or adulthood, and the experience of healthcare interactions; (3) Being informed, both about hypospadias in general, as well as about your specific body and medical history. There was overall a large variation in experiences. The latent theme across the data was the importance of owning your own narrative.

CONCLUSION

The experience of men with hypospadias in healthcare is complex and varied, highlighting the difficulty of fully standardised care. Based on our results, we suggest that follow-up should be offered in adolescence, and that ways of accessing care for late onset complications be made clear. We further suggest clearer consideration for the psychological and sexual aspects of hypospadias. Consent and integrity in all aspects and all ages of hypospadias care should be adapted to the maturity of the individual. Access to trustworthy information is key, both directly from educated healthcare staff and if possible, from websites or patient-led forums. Healthcare can play a key role in providing the growing individual with tools to understand and address concerns that may develop relating to their hypospadias through life, giving them ownership over their own narrative.

The orchestration of gene expression and the editing role of microRNA

In this short educational communication the ESPU Research Committee presents the role of non-coding RNA and how these can affect gene expression. In particular we discuss the role of microRNA on post transcriptional changes and how these may cause pathological conditions within Pediatric Urology and how microRNA could be useful in future clinical practice.

The positive predictive value of using fsh and Inhibin-B serum levels to diagnose gonadotropin insufficiency in bilateral cryptorchid boys is high

AIM OF STUDY

Despite early surgery, many boys with bilateral cryptorchidism at surgery have a reduced number of germ cells per tubular cross-section (G/T) in testicular biopsies and/or low inhibin-B with no elevated follicle-stimulating hormone (FSH) as expected based on a normal gonadotropin feed-back mechanism. Such boys have a high risk of later infertility because of insufficient gonadotropin stimulation and may benefit from adjuvant hormonal treatment. Testicular biopsies are not always wanted or accepted. The study aim was to investigate the value of a low inhibin-B and normal FSH to identify patients that might benefit from adjuvant hormonal treatment avoiding the need for testicular biopsy.

METHODS

A series of boys with cryptorchidism were evaluated with serum levels of inhibin-B and FSH in relation to G/T in testicular biopsies, which were compared to previously published age-matched normal control values.

RESULTS

A total of 365 boys who underwent bilateral orchidopexy between 0.4 and 7.8 (median: 2) years of age were included. Twenty-seven (7%) patients had increased FSH and low G/T, whereas 11 of these also had low inhibin-B indicating hypergonadotropic hypogonadism. Moreover, 85 (23%) patients between 0.75 and 7.5 (median: 2) years of age had both low G/T (median: 0.3) and low inhibin-B (median: 56 pg/ml) but normal FSH (median: 0.6 U/l) indicating a gonadotropin insufficiency. Three patients with normal FSH and low inhibin B had normal G/T.

DISCUSSION

Our study shows that if surgeons prefer to avoid testicular biopsies and only wish to rely on hormonal parameters (low inhibin-B and normal FSH) in order to diagnose a gonadotropin insufficiency as the cause of hypogonadism, they will identify only about 30% of such cases and overlook about 70% of patients sharing the same endocrinopathy. In addition, if surgeons treat patients for gonadotropin insufficiency only based on low inhibin-B and normal FSH they will solely treat patients with gonadotropin insufficiency and would not overtreat patients.

CONCLUSION

Adjuvant hormonal treatment was indicated by a gonadotropin insufficiency discerned in 23% of boys with bilateral cryptorchidism. Without histology, the clinicians are left with more difficult clinical judgments to identify patients for adjuvant hormonal treatment. The positive predictive value of low inhibin-B and normal FSH corroborated by low G/T was 0.97 (85/85 + 3), but the sensitivity was low (0.30).

Recommendations for whole genome sequencing in diagnostics for rare diseases

In 2016, guidelines for diagnostic Next Generation Sequencing (NGS) have been published by EuroGentest in order to assist laboratories in the implementation and accreditation of NGS in a diagnostic setting. These guidelines mainly focused on Whole Exome Sequencing (WES) and targeted (gene panels) sequencing detecting small germline variants (Single Nucleotide Variants (SNVs) and insertions/deletions (indels)). Since then, Whole Genome Sequencing (WGS) has been increasingly introduced in the diagnosis of rare diseases as WGS allows the simultaneous detection of SNVs, Structural Variants (SVs) and other types of variants such as repeat expansions. The use of WGS in diagnostics warrants the re-evaluation and update of previously published guidelines. This work was jointly initiated by EuroGentest and the Horizon2020 project Solve-RD. Statements from the 2016 guidelines have been reviewed in the context of WGS and updated where necessary. The aim of these recommendations is primarily to list the points to consider for clinical (laboratory) geneticists, bioinformaticians, and (non-)geneticists, to provide technical advice, aid clinical decision-making and the reporting of the results.

How the First Year of COVID-19 Affected Elective Pediatric Urology Patients: A Longitudinal Study Based on Waiting Lists and Surveys From 10 European Centers

Introduction

COVID-19 impacted healthcare systems worldwide, and elective surgical activity was brought to a minimum. Although children were not primarily affected by the disease, pediatric urology was halted by clinical closedown and staff allocation. We aimed to document how these prioritizations affected waiting lists, and to investigate how European centers dealt with the challenge of these logistical and financial prioritizations.

Materials and Methods

This was a 1-year prospective study, starting March 2020. Participants were surveyed at 3-month intervals about waiting lists for several common procedures as well as OR capacity and funding. Further, centers retrospectively reported on surgical and outpatient activity rates during 2019–2021. Waiting list tendencies were evaluated in relation to study baseline.

Results

A marked decrease in surgical and outpatient activity was seen in the spring of 2020. Some included pediatric urology centers were able to increase their budget (15%) and staff working hours (20%) during part of the study period. Still, at the end of the study, the centers had increased the total number of patients on waiting lists with 11%, whereas the average days on waiting lists had accumulated with 73%, yielding a total of 6,102 accumulated waiting days in the study population. Centers with decreased resources had markedly negative effects on waiting lists.

Conclusions

Correlations between COVID-19 derived burdening of healthcare systems and the availability of pediatric urology greatly depends on the prioritizations made at individual centers. Ongoing monitoring of these correlations is warranted to safely avoid unnecessary negative impact on the pediatric population.

Necessity of Prophylactic Extrapleural Chest Tube During Primary Surgical Repair of Esophageal Atresia: A Systematic Review and Meta-Analysis

Background

Esophageal atresia is corrected surgically by anastomosing and recreating esophageal continuity. To allow the removal of excess fluid and air from the anastomosis, a prophylactic and temporary intraoperative chest tube (IOCT) has traditionally been placed in this area during surgery. However, whether the potential benefits of this prophylactic IOCT overweigh the potential harms is unclear.

Objective

To assess the benefits and harms of using a prophylactic IOCT during primary surgical repair of esophageal atresia.

Data Sources

We conducted a systematic review with a meta-analysis. We searched Cochrane Central Register of Controlled Trials (2021, Issue 12), MEDLINE Ovid, Embase Ovid, CINAHL, and Science Citation Index Expanded and Conference Proceedings Citation Index-(Web of Science). Search was performed from inception until December 3rd, 2021.

Study Selection

Randomized clinical trials (RCT) assessing the effect of a prophylactic IOCT during primary surgical repair of esophageal atresia and observational studies identified during our searches for RCT.

Data Extraction and Synthesis

Two independent reviewers screened studies and performed data extraction. The certainty of the evidence was assessed by GRADE and ROBINS-I.

PROSPERO Registration

A protocol for this review has been registered on PROSPERO (CRD42021257834).

Results

We included three RCTs randomizing 162 neonates, all at overall "some risk of bias." The studies compared the placement of an IOCT vs. none. The meta-analysis did not identify any significant effect of profylacitic IOCT, as confidence intervals were compatible with no effect, but the analyses suggests that the placement of an IOCT might lead to an increase in all-cause mortality (RR 1.66, 95% CI 0.76-3.65; three trials), serious adverse events (RR 1.08, 95% CI 0.58-2.00; three trials), intervention-requiring pneumothorax (RR 1.65, 95% CI 0.28-9.50; two trials), and anastomosis leakage (RR 1.66, 95% CI 0.63-4.40). None of our included studies assessed esophageal stricture or pain. Certainty of evidence was very low for all outcomes.

Conclusions

Evidence from RCTs does not support the routine use of a prophylactic IOCT during primary surgical repair of esophageal atresia.

Serial Inhibin B Measurements in Boys with Congenital Monorchism Indicate Compensatory Testicular Hypertrophy in Early Infancy

AIM

 Congenital monorchism is considered a condition in which an initially normal testis has existed but subsequently atrophied and disappeared due to a third trimester catastrophe (presumably torsion). Since inhibin B concentrations appear related to Sertoli and germ cells number, we evaluated pre- and postoperative inhibin B of boys with congenital monorchism to determine whether the well-known hypertrophy of the contralateral testis was reflected in inhibin B concentrations.

MATERIALS AND METHODS

 Twenty-seven boys consecutively diagnosed with congenital monorchism (median age 12 months) underwent follow-up with reproductive hormones 1 year postoperatively (median age 25 months). The results were compared with inhibin B of 225 boys with congenital nonsyndromic unilateral cryptorchidism, by converting values to multiple of the median (MoM) for age in normal boys.

RESULTS

 Ten boys (37%) had blind-ending vessels and ductus deferens (vanished testis) and the remaining (63%) had testicular remnants. At the time of diagnostic procedure, monorchid boys did not have significantly lower inhibin B (median 114, range 20-208) than unilateral cryptorchid boys (136, 47-393) (p = 0.27). During follow-up, MoM values of inhibin B increased in monorchid boys (median 0.59 to 0.98) and in unilateral cryptorchid boys (0.69 to 0.89) (both p < 0.0001). Compared with the concentration at surgery, an additional 44% monorchid boys had inhibin B MoM values higher than 1.0, whereas only additional 23% of unilateral cryptorchid boys exhibited such values (p = 0.04).

CONCLUSION

 Generally, inhibin B MoM values were normalized during follow-up in boys with congenital monorchism, reflecting compensatory hypertrophy within the first 2.5 years of life. The compensatory capacity to increase was better in monorchism than in unilateral cryptorchidism.

Robot-Assisted vs. Open Appendicovesicostomy in Pediatric Urology: A Systematic Review and Single-Center Case Series

INTRODUCTION

Appendicovesicostomy (APV) is the preferred choice of continent catheterizable channels in pediatric urology. The introduction of robot-assisted laparoscopic techniques has been correlated to superior cosmesis and convalescence and is now increasingly implemented for APV procedures. We aimed to perform a systematic review of the literature comparing open vs. robotic APV regarding possible differences in postoperative outcomes and to evaluate these findings with our own initial experiences with robotic APV compared to our previous open procedures.

METHODS

We evaluated the first five patients undergoing robotic APV at our institution and compared 1-year outcomes with a consecutive series of 12 patients undergoing open APV. In a systematic literature review, we screened studies from PubMed, EMBASE, and CENTRAL comparing open and robotic APV in pediatric urology (current to December 2021) and performed meta-analyses on postoperative outcomes comparing the two groups and evaluated the grade of evidence.

RESULTS

We found significantly shortened postoperative length of stay in the robotic group (p = 0.001) and comparable 1-year complication rates in robotic vs. open APV patients. We systematically screened 3,204 studies and ultimately included three non-randomized studies comparing postoperative outcomes of robotic and open APV for quantitative analysis. The open and robotic approaches performed equally well regarding overall postoperative complications, surgical reintervention, and stomal stenosis. Two of the included studies reported comparable stomal continence rates and shortened postoperative length of stay in the robotic group, in agreement with the findings in our own series.

CONCLUSION

Robotic APV is equally safe to the conventional open approach with additional advantages in postoperative hospitalization length.

Genetics: The diagnostic frontier in pediatric urology

In the course of human history few scientific breakthroughs can rival the importance of the discovery of DNA. Our ever increasing ability to unravel the secrets contained in this molecule allow new insight in to the etiology and eventual treatment of human conditions ranging from congenital structural disorders to cancer. It is the focus of this article to touch upon sequencing technologies and their potential to provide information that can revolutionize healthcare.

A conversation on how animal experimental studies allies with translational medicine

Basis science research in pediatric urology studies physiological questions in animal models to provide new data on how to treat patients. We sat down with Jens-Christian Djurhuus to discuss both practical and philosophical questions on how to best perform basic science research. Initial questions such as "What type of questions are best studied in animal models?" and "Which animal model should I use?" help us answer the basic question of "What is a good research topic?". To take advantage of his experience leading a research team, we went on to discuss "How do you lead a research team?" and "How do we make sure that basic science research translates to clinical practice?". As research funding becomes scarce, we thank Professor Djurhuus for his insights on how to focus basic science research on relevant topics that are easily translatable to the care of children.

COVID-19 and research in pediatric urology

COVID-19 began in December 2019 then spread worldwide. Providers, including pediatric urologists, had to adapt their clinical processes, and many non-covid research activities were suspended. COVID-19 impacts how research is financed, performed, and published, and is itself the subject of intense research. We present current research and publications specifically related to the urinary tract and the pediatric population.

The impact of early and successful orchidopexy on hormonal follow-up for 208 boys with bilateral non-syndromic cryptorchidism

PURPOSE

Inhibin-B is produced by Sertoli cells and decreased values might be associated with impaired fertility potential. The aim of the study was to evaluate the impact of bilateral orchidopexy on serum inhibin-B and follicle-stimulating hormone (FSH).

METHODS

A cohort study including 208 bilateral cryptorchid boys (median age: 1.7 year) was evaluated with serum inhibin-B and FSH in relation to histological parameters. Based on the fertility potential, the boys were divided into three subgroups. At follow-up (median age: 2.7 years) the boys were evaluated with FSH and in case of inhibin-B using multiple of the median (MoM).

RESULTS

Inhibin-B MoM improved significantly at follow-up. In 32 boys with high FSH at orchidopexy 63% normalized FSH and 59% increased MoM inhibin-B, but 31% had impaired inhibin-B at follow-up. In 105 boys with transient hypogonadotropic hypogonadism, 52% increased inhibin-B MoM but 31% had impaired inhibin-B at follow-up. In 71 boys with normal FSH, inhibin-B, and G/T, 54% increased inhibin-B MoM and 15% had impaired inhibin-B at follow-up. The effect of the surgery was best in patients younger than 1 year.

CONCLUSION

Orchidopexy, especially before 1 year of age, improves the fertility potential in bilateral cryptorchidism. At follow-up, 26% (54/208) had a risk of infertility based on inhibin-B.

Creation of Tissue-Engineered Urethras for Large Urethral Defect Repair in a Rabbit Experimental Model

Introduction: Tissue engineering is a potential source of urethral substitutes to treat severe urethral defects. Our aim was to create tissue-engineered urethras by harvesting autologous cells obtained by bladder washes and then using these cells to create a neourethra in a chronic large urethral defect in a rabbit model. Methods: A large urethral defect was first created in male New Zealand rabbits by resecting an elliptic defect (70 mm²) in the ventral penile urethra and then letting it settle down as a chronic defect for 5-6 weeks. Urothelial cells were harvested noninvasively by washing the bladder with saline and isolating urothelial cells. Neourethras were created by seeding urothelial cells on a commercially available decellularized intestinal submucosa matrix (Biodesign® Cook-Biotech®). Twenty-two rabbits were divided into three groups. Group-A (n = 2) is a control group (urethral defect unrepaired). Group-B (n = 10) and group-C (n = 10) underwent on-lay urethroplasty, with unseeded matrix (group-B) and urothelial cell-seeded matrix (group-C). Macroscopic appearance, radiology, and histology were assessed. Results: The chronic large urethral defect model was successfully created. Stratified urothelial cultures attached to the matrix were obtained. All group-A rabbits kept the urethral defect size unchanged (70 ± 2.5 mm²). All group-B rabbits presented urethroplasty dehiscence, with a median defect of 61 mm² (range 34-70). In group-C, five presented complete correction and five almost total correction with fistula, with a median defect of 0.3 mm² (range 0-12.5), demonstrating a significant better result (p = 7.85 × 10^-5). Urethrography showed more fistulas in group-B (10/10, versus 5/10 in group-C) (p = 0.04). No strictures were found in any of the groups. Group-B histology identified the absence of ventral urethra in unrepaired areas, with squamous cell metaplasia in the edges toward the defect. In group-C repaired areas, ventral multilayer urothelium was identified with cells staining for urothelial cell marker cytokeratin-7. Conclusions: The importance of this study is that we used a chronic large urethral defect animal model and clearly found that cell-seeded transplants were superior to nonseeded. In addition, bladder washing was a feasible method for harvesting viable autologous cells in a noninvasive way. There is a place for considering tissue-engineered transplants in the surgical armamentarium for treating complex urethral defects and hypospadias cases.

Parental Acceptance Rate of Testicular Tissue Cryopreservation in Danish Boys with Cryptorchidism

Despite orchidopexy within the first year of life, 20-25% of boys with nonsyndromic cryptorchidism may risk infertility according to histological and hormonal data obtained during surgery. The aim of this study was to evaluate the acceptance rate of testicular tissue cryopreservation among parents of prepubertal boys with cryptorchidism. Fourteen boys with cryptorchidism and high infertility risk were offered cryopreservation as an additional procedure after orchidopexy based on abnormal histopathological findings at primary surgery, whereas 27 boys with bilateral cryptorchidism were offered cryopreservation at the initial orchidopexy. A total of 90% of parents (37/41, 13/14, and 24/27) gave consent to perform cryopreservation, despite being well-informed that the procedural efficacy is largely unproven and may only be needed in about 20% of cases. The number of germ cells per tubule cross-section was 0.03-1.70 (median 0.37) and 22 boys (54%, 22/41) had a value below the lower range. Twelve boys (29%, 12/41) had no type A dark spermatogonia in their biopsy. Cryopreservation of testicular tissue is the first step to introduce spermatogonial stem cell-based therapy into clinical male infertility treatment. At the time of orchidopexy, a testicular biopsy can be collected to ascertain the infertility risk, and it may be an option for boys with bilateral cryptorchidism to have spermatogonial stem cells frozen as a fertility reserve.

How to more effectively determine what is true: The limits of intuition

The plethora of scientific data and explosion of published materials often leave it challenging to develop a clear and concise overview of many scientific topics. A number of factors may contribute to our misunderstanding. It is the focus of this article to describe primary reasons for failure to establish a clear, factual and functional understanding regarding scientific areas of inquiry.

0617 Optimization of OSA Screening in a Black Population

Introduction

Racial disparities in the prevalence and severity of Obstructive Sleep Apnea (OSA) in Black Americans may play an important contributory role in the increased burden of cardiometabolic disease experienced by this population. Effective screening for OSA could permit early recognition and treatment, thereby preventing future the adverse cardiovascular outcomes which contribute to a decreased life expectancy. The STOP-BANG questionnaire is a validated screening tool for OSA as demonstrated in many populations and settings. Unfortunately, Blacks have typically been underrepresented in studies evaluating the sensitivity and specificity of the tool. Potentially unique biologic and psychosocial factors may affect the phenotypic expression of OSA and influence the performance of the STOP-BANG. Data are needed regarding the reliability of the tool for this population and potentially modifications to optimize its usefulness.

Methods

Data were from 204 patients evaluated at the Howard University Hospital Sleep Disorder Center between April 2018 and June 2019. Records were reviewed for demographic information, body mass index (BMI), neck circumference, and medical history, including the presence of snoring, tiredness/sleepiness, observed apneas, and hypertension and results of sleep study testing. Data were analyzed using SPSS software. Subcomponents of the STOP-BANG scoring criteria were adjusted to improve performance.

Results

Mean age was 48.5. 62% of subjects were female and mean BMI was 40.2 The mean ESS was 9.9. The mean AHI was 27.7 with a prevalence of mild or greater OSA (AHI &gt;5) of 80%. Scoring of the STOP-BANG using a criterion of 3 or greater as indicating increased risk demonstrated a sensitivity of 90%, specificity of 8%, PPV of 80%, and NPV of 17%. Performance was worse for women then men. Multiple adjustments to scoring were evaluated to improve accuracy.

Conclusion

Similar to its performance in other populations, the STOP-BANG demonstrated high sensitivity but very poor specificity and overall poor accuracy in a Black population referred for Sleep Medicine Consultation to an urban university hospital. Performance was worse for women than men. Modifications are presented to try to improve performance and the clinical utility for this population.

Support

Howard University RCMI

Molecular and histological studies of bladder wound healing in a rodent model

The field of regenerative medicine encounters different challenges. The success of tissue-engineered implants is dependent on proper wound healing. Today, the process of normal urinary bladder wound healing is poorly characterized. We aspired to explore and elucidate the natural response to injury in an in vivo model in order to further optimize tissue regeneration in future studies. In this study, we aimed to characterize histological and molecular changes during normal healing in a rat model by performing a standardized incisional wound followed by surgical closure. We used a rodent model (n = 40) to follow the healing process in the urinary bladder for 28 days. Surgical exposure of the bladder without incision (n = 40) was performed in controls. Histological characterization and western blot analyses of proteins was carried out using specific staining and markers for inflammation, proliferation, angiogenesis, and tissue maturation. For the molecular characterization of gene expression total RNA was collected for RT² -PCR in wound healing pathway arrays. Analysis of histology revealed distinct, but overlapping, phases of healing with a local inflammatory response (days 1-8) simultaneous with a rapid formation of granulation tissue and proliferation (days 2-8). We also identified significant changes in gene expression related to inflammation, proliferation, and extracellular matrix formation. Healing of an incisional wound in a rodent urinary bladder demonstrated that all the classical phases of wound healing: hemostasis, inflammation, proliferation followed by tissue maturation were present. Our data suggest that the bladder and the skin share similar molecular signaling during wound healing, although we noted differences in the duration of each phase compared to previous studies in rat skin. Further studies will address whether our findings can be extrapolated to the human bladder.

Further medical experience will be required to validate these results: How experience -based medicine shapes the validity of medical evidence

This communication contextualizes the importance of clinical experience or experience-based medicine within the current paradigm of evidence-based medicine, complementing our previously published series of five short educational articles on evidence-based medicine. Previously we focused on optimizing medical decisions using publications of well-conducted research. Previous commentaries included a backgrounder, the hierarchy of evidence, data acquisition, tools for critical appraisal, and clinical use of evidence based medicine.

Pathogenic copy number variants are detected in a subset of patients with gastrointestinal malformations

Background

Gastrointestinal atresias and urological defects are main causes of pediatric surgery in infants. As copy number variants (CNVs) have been shown to be involved in the development of congenital malformations, the aim of our study was to investigate the presence of CNVs in patients with gastrointestinal and urological malformations as well as the possibility of tissue‐specific mosaicism for CNVs in the cohort.

Methods

We have collected tissue and/or blood samples from 25 patients with anorectal malformations, esophageal atresia, or hydronephrosis, and screened for pathogenic CNVs using array comparative genomic hybridization (array‐CGH).

Results

We detected pathogenic aberrations in 2/25 patients (8%) and report a novel possible susceptibility region for esophageal atresia on 15q26.3. CNV analysis in different tissues from the same patients did not reveal evidence of tissue‐specific mosaicism.

Conclusion

Our study shows that it is important to perform clinical genetic investigations, including CNV analysis, in patients with congenital gastrointestinal malformations since this leads to improved information to families as well as an increased understanding of the pathogenesis.

Evidence-based medicine V: how to use in clinical practice

In this penultimate installment in the educational series on evidence-based medicine, the Research Committee of the European Society of Pediatric Urology will focus on clinical application. In previous communications, optimizing medical decisions was focused on through the use of well-conducted research publications, and the topics of background, hierarchy of evidence, information acquisition, and critical appraisal tools were covered. The goal is to guide the clinician in using evidentiary tools for setting up a clinical question, finding appropriate information, searching appropriate databases, and evaluating the results with the patient in mind.

The ANTENATAL multicentre study to predict postnatal renal outcome in fetuses with posterior urethral valves: objectives and design

Background

Posterior urethral valves (PUV) account for 17% of paediatric end-stage renal disease. A major issue in the management of PUV is prenatal prediction of postnatal renal function. Fetal ultrasound and fetal urine biochemistry are currently employed for this prediction, but clearly lack precision. We previously developed a fetal urine peptide signature that predicted in utero with high precision postnatal renal function in fetuses with PUV. We describe here the objectives and design of the prospective international multicentre ANTENATAL (multicentre validation of a fetal urine peptidome-based classifier to predict postnatal renal function in posterior urethral valves) study, set up to validate this fetal urine peptide signature.

Methods

Participants will be PUV pregnancies enrolled from 2017 to 2021 and followed up until 2023 in >30 European centres endorsed and supported by European reference networks for rare urological disorders (ERN eUROGEN) and rare kidney diseases (ERN ERKNet). The endpoint will be renal/patient survival at 2 years postnatally. Assuming α = 0.05, 1–β = 0.8 and a mean prevalence of severe renal outcome in PUV individuals of 0.35, 400 patients need to be enrolled to validate the previously reported sensitivity and specificity of the peptide signature.

Results

In this largest multicentre study of antenatally detected PUV, we anticipate bringing a novel tool to the clinic. Based on urinary peptides and potentially amended in the future with additional omics traits, this tool will be able to precisely quantify postnatal renal survival in PUV pregnancies. The main limitation of the employed approach is the need for specialized equipment.

Conclusions

Accurate risk assessment in the prenatal period should strongly improve the management of fetuses with PUV.

Evidence-based medicine III: level of evidence

The present article is the third installment in a five-part series related to evidence-based medicine (EBM) provided by the European Society for Paediatric Urology Research Committee. It will present the different levels of evidence (i.e. systematic review, randomized controlled trial, cohort study) available to clinicians and researchers and describe the strengths of each study type. While EBM provides a valuable construct to aid in medical decision-making, it remains imperative that this information be interpreted and applied in the clinical context with a good dose of common sense.

Evidence Based Medicine IV: how to find an evidence-based answer to a clinical question? Make a critically appraised topic!

This manuscript is the fourth in a five part series related to evidence based medicine (EBM) provided by the European society of pediatric urology (ESPU) research committee. It will present a way to come to a quick and critical appraisal of available evidence on a specific topic: a CAT (critically appraised topic). The way how to write a cat is described for interventions to be compared to a control group, and for other, more generalized clinical questions. While systematic reviews provide a throughout overview of all evidence available, a CAT provides a shorter way to come to quick insights based on EBM.

Urothelial cell senescence is not linked with telomere shortening

The success of regenerative medicine relies in part on the quality of the cells implanted. Cell cultures from cells isolated from bladder washes have been successfully established, but molecular changes and cell characteristics have not been explored in detail. In this work, we analysed the role of telomere shortening in relation to the regenerative potential and senescence of cells isolated from bladder washes and expanded in culture. We also analysed whether bladder washes would be a potential source for attaining stem cells or promoting stem cell proliferation by using two different substrates to support their growth: a feeder layer of growth-arrested murine fibroblasts J2 3T3 cells and a xeno-free human recombinant laminin-coated surface. We found no association between telomere shortening and senescence in urothelial cells in vitro. Urothelial cells had a stable telomere length and expressed mesenchymal stem cells markers but failed to differentiate into bone or adipocytes. Feeder layer showed an advantage to laminin-coated surfaces in respect to proliferative capacity with the expense of risking that feeder layer cells could persist in later passages. This emphasizes the importance of using carefully controlled culture conditions and molecular quality controls before autotransplantation in future clinical settings. In conclusion, urothelial cells isolated by bladder washes show regenerative potential that need further understanding. Senescence in vitro might be due to cellular stress, and if so, further improvements in culture conditions may lead to longer cell life and higher proliferative capacity.

EBM II: How to perform a literature search

The present article is a second part related to evidence based medicine (EBM) in a series of five by the European society for paediatric urology (ESPU) research committee. It will present the different databases/search engines available to clinicians and researchers and describe strategies to focus the search to one's particular needs. Indeed, databases/search engines used and search strategy should vary according to the goal of the research. If the aim is to address a clinical problem, the search should allow to identify a small number of most pertinent articles (high specificity); if the search is for research purposes, instead, it should ensure no meaningful articles are overlooked (high sensitivity).

How the ESPU grades clinical abstracts

The ability to consistently review abstracts in an unbiased and objective fashion is a skill that most academics hope to master. However, robust standardized rating systems are sparse, with most scientific boards leaving the task of rating abstracts poorly defined and at the whim of the reviewer. In an effort to bring consistency to this process, in 2013, the ESPU board adopted an abstract rating system that has been previously used in the field of plastic surgery and orthopedics. (van der Steen et al., 2004; Poolman et al., 2007). The aim of this manuscript is to outline this practice.

Fetal subcutaneous cells have potential for autologous tissue engineering

Major congenital malformations affect up to 3% of newborns. Infants with prenatally diagnosed soft tissue defects should benefit from having autologous tissue readily available for surgical implantation in the perinatal period. In this study, we investigate fetal subcutaneous cells as cellular source for tissue engineering. Fetal subcutaneous biopsies were collected from elective terminations at gestational Week 20-21. Cells were isolated, expanded, and characterized in vitro. To determine cell coverage, localization, viability, and proliferation in different constructs, the cells were seeded onto a matrix (small intestine submucosa) or in collagen gel with or without poly(ε-caprolactone) mesh and were kept in culture for up to 8 weeks before analysis. Angiogenesis was analysed through a tube-forming assay. Fetal subcutaneous cells could be expanded until 43 ± 3 population doublings, expressed mesenchymal markers, and readily differentiate into adipogenic and osteogenic lineages. The cells showed low adherence to small intestine submucosa and did not migrate deep into the matrix. However, in collagen gels, the cells migrated into the gel and proliferated with sustained viability for up to 8 weeks. The cells in the matrices expressed Ki67, CD73, and α-smooth muscle actin but not cytokeratin or CD31. Fetal cells derived from subcutaneous tissue demonstrated favourable characteristics for preparation of autologous tissue transplants before birth. Our study supports the theory that cells could be obtained from the fetus during pregnancy for tissue engineering purposes after birth. In a future clinical situation, autologous transplants could be used for reconstructive surgery in severe congenital malformations.