Pediatric testicular torsion management practices A survey of Canadian urologists.

INTRODUCTION: Pediatric testicular torsion (TT) is a urologic emergency that may result in testicular loss if left untreated. Testicular salvage is dependent on prompt intervention, and thus delays in diagnosis and management may threaten testicular viability. Knowledge of real-world Canadian practice patterns for pediatric TT will allow optimization of practices based on resource availability and geographic limitations to improve care. METHODS: An electronic survey on pediatric TT management was distributed to Canadian urologists. Descriptive statistics were performed on respondent demographic factors, hospital policies and barriers to care, surgical approaches, and transfer practices. Respondent practice patterns were analyzed based on geographic location and training. RESULTS: Thirty-four urologists responded, with most respondents operating a community practice. Ultrasonography (US) was frequently used to support TT diagnosis. Despite this, poor US access was often cited as a barrier to care, with particular impact on rural urologists. Neonatal patients and <10 years old were commonly transferred to a pediatric hospital for definitive management due to surgeon discomfort and hospital policies. Reported transport methods commonly included use of the patient's own vehicle or ambulance based on availability and timing. CONCLUSIONS: Neonatal patients and patients under 10 years old are most commonly reported to be transferred to pediatric hospitals for TT management. Patients located in rural locations and at centers with limited US access may be at risk for delayed diagnosis and treatment. Pathways for prompt management of suspected TT may better serve these younger pediatric patients.

Geospatial analysis of hypospadias and cryptorchidism prevalence rates based on postal code in a Canadian province with stable population.

INTRODUCTION: Hypospadias and cryptorchidism are hormone-mediated malformations that occur during male development. Prevalence rates of hypospadias and cryptorchidism are thought to be increasing worldwide. In-utero exposure to endocrine-disrupting chemicals (EDCs) may have a role in the occurrence of these malformations. Our group has reported significant clustering of hypospadias and cryptorchidism at the county level in areas of intense agricultural activity in the Canadian province of Nova Scotia (NS). Finer scale spatial analysis has shown clustering near urban centres. OBJECTIVES: The objectives of the study were: 1) to perform a granular geospatial analysis of hypospadias and cryptorchidism prevalence, at the postal code level, of all babies born in NS over a 26-year period; and 2) to determine whether there is spatial correlation between these conditions and industries linked to toxic output. STUDY DESIGN: Cases of hypospadias and cryptorchidism were identified based on ICD-10 codes from the Nova Scotia Atlee Perinatal Database with records of all live births in NS between 1988 and 2013. Data were geocoded and mapped based on the three first digits of the maternal postal code (Forward Sortation Area [FSA]). Regional prevalence of congenital anomalies was calculated for each of the 77 FSAs. To identify statistically significant high and low prevalence clusters for each anomaly, Local Morans I was used on the spatial data. Geospatial point data was created for industries linked to toxic output and correlation between clusters of malformations and proximity to these industries was assessed. RESULTS: During the study period, there were 1045 cases of hypospadias and 993 cases of cryptorchidism. Both hypospadias and cryptorchidism demonstrated statistically significant areas of high prevalence clusters. There was no significant spatial correlation between the local clustering of the congenital malformations and proximity to toxic industries. DISCUSSION AND CONCLUSION: Our study shows heterogeneity in the distribution of hypospadias and cryptorchidism, which is consistent with previously published works. In this follow-up, granular geospatial analysis of hypospadias and cryptorchidism prevalence in an area with stable population, we did not confirm the previous findings of high clustering in areas of intense agricultural activity. Furthermore, our analysis did not find high clustering of the congenital malformations in areas near toxic industries to support a clear environmental role in their development. Some of the limitations include underdiagnosis of hypospadias and cryptorchidism (as they both present with a clinical spectrum and are non-life threatening), and limited data currently available on the route of exposure to EDC industries in Nova Scotia.

Shared decision-making for pediatric elective penile surgery.

INTRODUCTION: In pediatric surgery, proxy decision-makers are frequently involved in treatment planning and may experience decisional conflict (DC). Shared decision-making (SDM) approaches may be effective to remedy DC. This study investigates DC and SDM involvement in elective pediatric penile surgery. METHODS: Forty-four parents of children aged <8 years undergoing elective penile surgery consultations at a tertiary pediatric hospital were prospectively enrolled. Patient and physician questionnaires were used to assess the SDM process and the SURE (Sure of myself; Understand information; Risk-benefit ratio; Encouragement) screening test was used to assess DC. RESULTS: Thirty-seven (84.1%) mothers and seven (15.9%) fathers were enrolled for circumcision (n=33, 75.0%) and distal hypospadias repair (n=11, 25.0%) consultations, with 21 (47.7%) choosing to proceed with surgery. Seven (15.9%) participants experienced clinically significant DC. Participant gender was not associated with higher levels of DC (p=0.318). The average patient and physician SDM scores were 88.2±10.0 and 85.3±7.4, respectively, with no correlation found between participant and physician perception of SDM involvement (p=0.168, p=0.276). DC was significantly associated with lower participant and physician ratings of SDM. CONCLUSIONS: There was a high perception of SDM involvement by both parents and pediatric urologists regarding elective penile surgery. Of the 15% of parents experiencing DC, there was an association with lower participant and physician levels of SDM involvement. Despite high SDM scores overall, discrepancies exist between the perceived physician and participant SDM involvement.

Concurrent Multicystic Dysplastic Kidney, Posterior Urethral Valves, and Obstructive Ureterocele in a Male Pediatric Patient: A Case Report.

Congenital anomalies of the kidney and urinary tract (CAKUT) are diagnosed in approximately 3-6 per 1000 live births and represent a spectrum of urologic conditions impacting the kidneys, ureter, bladder, and urethra.1 Although both are considered under the classification of CAKUT, there is no known unifying pathophysiologic mechanism for ureteroceles and posterior urethral valves with only 1 case report noted in the literature. Herein we report the only documented case of a patient with CAKUT related to posterior urethral valves, ureterocele, and multicystic dysplastic kidney.

A survey of management preferences for bladder exstrophy and cloacal anomalies among Canadian pediatric surgeons and urologists.

PURPOSE: This study examined the current referral patterns and preferences of Canadian Association of Paediatric Surgeons (CAPS) and Pediatric Urologists of Canada (PUC) members for management of bladder exstrophy and cloacal anomalies (BECA). METHODS: We invited CAPS and PUC members to participate in an online survey using RedCap. Demographic variables, years in practice, current referral patterns and local expertise at the participants' institution were collected. Participants' preferences towards three distinct referral models were assessed using Likert scales: no centralization of care, centralization in one or two national centres of excellence, or a consortium-based approach. RESULTS: There were 82 survey respondents (2/3 were CAPS members, 35.4% female, 72% in practice for >10 years). Although >90% of participants agreed/somewhat agreed that surgical volumes impact outcomes, 58% reported not referring out BECA patients for treatment; about 50% recognized the existence of a local dedicated expert. In terms of referral preferences, 84% of participants favoured identification of a few centres with expertise based on geographic location (a consortium-based approach), while only 7% chose a one or two national centres of excellence model. Over half of participants agreed/somewhat agreed with participating in trials of a consortium-based approach in Canada. CONCLUSION: Most CAPS and PUC members do not refer BECA patients elsewhere for treatment. Nonetheless, most surgeons recognize the importance of volume to improve outcomes and show willingness to participate in trials to concentrate experience; most participants favour a consortium-based approach through identification of a few centres of excellence based on geographic location.

Psychosocial Distress in Parents with Children Awaiting Surgery during the COVID-19 Pandemic.

Due to resource restrictions related to the COVID-19 pandemic, many pediatric patients are facing substantial delays for surgery, potentially resulting in additional distress for caregivers. We aimed to assess the experiences and psychosocial distress of parents during COVID-19 as they relate to the pandemic, waiting for surgery, and the combined effects of both events. The was a cross-sectional qualitative study. Parents with children who faced treatment delays during the initial wave of the COVID-19 pandemic for elective, non-emergent procedures across a variety of surgical specialties were recruited. Semi-structured telephone interviews and thematic analysis were utilized. Thematic saturation was reached with eighteen participants. Four themes were identified: coping with COVID-19, distress levels, quality and nature of communication with the surgical team, and the experience of COVID-19 related hospital restrictions. Participants reported varying levels of distress due to the delay in surgery, such as the fear of developmental delay or disease progression for their child. They also indicated their own physical and mental health had been impacted by emotional distress related to both COVID-19 and delays in treatment. Most participants experienced the COVID-19-related hospital restrictions as distressing. This related predominantly to limiting in-hospital caregivers to only one caregiver. Participants were found to have substantial levels of psychosocial distress. Targeted social and emotional support may be helpful in reducing parental distress as the pandemic timeframe continues. Within the limits of individual health systems, reducing restrictions to the number of allowed care givers may help allay distress felt by parents.

The current landscape of urological undergraduate education in Canada.

INTRODUCTION: Urological presentations are commonly seen in primary care and urologists are concerned that educational gaps exist in undergraduate curricula in Canadian medical schools. A pan-Canadian survey of undergraduate urology education directors (UUEDs) was used to determine the current status of undergraduate urology education in Canada. METHODS: In the fall of 2018, a survey was administered to all 17 UUEDs representing every Canadian medical school. The survey assessed multiple factors, including the timing and duration of urologist-led instruction, the perceived adequacy of urological content in the curriculum, and the level of preparedness of graduating students. RESULTS: The response rate was 100%. Variation in the duration (mean total instructional hours: 22.5±17.2 [5-75] hours) and timing of formal urological instruction was seen. The majority of schools covered core content areas, however, erectile dysfunction, urotrauma, and pediatric urology topics were under-represented. One school had a mandatory urology clerkship rotation (one week), while the other 16 schools offered a selective, with 24.3% of students completing this experience. The majority of UUEDs (64.7%) believed the curricular time devoted to urology was inadequate, 29.4% felt that their graduates were unprepared to diagnose and treat common urological problems, and 76.5% strongly agreed or agreed that a national urology curriculum would be useful. CONCLUSIONS: There was significant variability in the duration of instruction and delivery of urological topics in Canadian medical schools. There was a perceived need for more urological instruction by most UUEDs, who welcomed a more standardized national curriculum as a strategy to address this need.

Association of vesicoureteral reflux and gastroesophageal reflux disease in children: A population-based study.

INTRODUCTION: Practitioners have anecdotally hinted at a possible association between gastroesophageal reflux disease (GERD) and vesicoureteral reflux (VUR). We sought to identify an association in diagnosis between GERD and VUR using a population-based dataset in a well-defined geographic area covered by a single-payer healthcare system. METHODS: A retrospective review of individuals aged 0-16 years registered in the Nova Scotia Medical Service Insurance database from January 1997 to December 2012 was completed. Presence of GERD and VUR were ascertained based on billing codes. The baseline prevalence of GERD and VUR was calculated for this population for the same time period. Proportions of VUR patients with and without GERD were compared. The risk of being diagnosed with VUR in patients with GERD controlling for sex was calculated. RESULTS: Of 404 300 patients identified, 6.6% had a diagnosis of GERD (n=27 092), 0.33% had a diagnosis of VUR (n=1348), and 0.08% were diagnosed with both (n=327). Among patients with VUR, the prevalence of GERD was 24.3% compared to 6.6% in patients without VUR (p<0.0001). Among patients with GERD, the prevalence of VUR was 1.2% compared to 0.27% in patients without (p<0.0001). The risk of being diagnosed with VUR was higher in the presence of GERD (odds ratio [OR] 4.49; 95% confidence interval [CI] 3.96-5.09; p<0.0001), irrespective of sex. CONCLUSIONS: The odds of being diagnosed with VUR is more than 4.5 times higher in an individual with GERD. The clinical significance of this association remains to be explored.

Point-of-care influences orchiectomy rates in pediatric patients with testicular torsion.

OBJECTIVES: The objective of this study was to determine whether point-of-care (community hospitals vs. tertiary centers) or treatment-delaying variables (transfer, emergency room [ER] throughput, and distance traveled) affect orchiectomy rates in minors with testicular torsion (TT) using a national database. STUDY DESIGN: This was a retrospective cohort study using prospectively collected data by the Canadian Institute of Health Information (CIHI) between 2010 and 2015. All Canadian male patients in the CIHI database aged <18 years with TT based on International Classification of Diseases (ICD) codes were included, except for those residing in Quebec. Variables collected were age, type of treating institution (community small/medium, community large, or tertiary/academic), transfer for definitive treatment, road distance traveled, and ER throughput. The outcome was testicular loss based on intervention codes for orchiectomy/orchidopexy. Univariable and multivariable analyses were performed using logistic regression. RESULTS: A total of 1713 minors with TT were included. Overall orchiectomy rate was 28%. Most patients (52%) were treated at tertiary hospitals. Small/medium community hospitals depicted the lowest odds of orchiectomy on univariable and multivariable analyses (odds ratio [OR] = 0.54, confidence interval [CI]: 0.37-0.79, p < 0.001); academic hospitals were also associated with a lower odds of orchiectomy than large community ones. Transfer and distance traveled were not associated with the outcome. Age >12 and ER throughput less than 1 h were significantly associated with lower orchiectomy rates. In a subgroup analysis of patients aged <12 years (n = 278), transfer was the only factor associated with increased risk of orchiectomy (OR = 2.41 , CI: 1.09-5.33; p = 0.03). DISCUSSION: This study showed that small and medium community hospitals had the lowest orchiectomy rates in minors with TT in Canada (Figure). However, on multivariable analysis, they performed similarly to tertiary/academic hospitals, with both being superior to large community hospitals. Transfer and distance traveled did not affect orchiectomy rates. Emergency room throughput had a statistically significant association with orchiectomy rates in every analysis and based on the study data would constitute the best target for policies aimed at reducing orchiectomy rates for TT in minors. The main limitation of this study is the inability to evaluate long-term testicular viability of patients not undergoing orchiectomy (i.e., true testicular salvage). CONCLUSIONS: Type of hospital treating facility (point-of-care) affects orchiectomy rates in minors with TT. Small/medium community hospitals depict the lowest orchiectomy rates in Canada. Transfer to another facility for definitive care and distance traveled did not affect orchiectomy rates, except in a subgroup analysis of prepubertal boys. Longer ER throughput and prepubertal age were consistently associated with loss of the testicle.

The role of adenotonsillectomy in the treatment of primary nocturnal enuresis in children: A systematic review.

INTRODUCTION: Primary nocturnal enuresis (PNE) is a challenging condition for physicians, patients and families. Although the etiology remains unclear, sleep-disordered breathing (SDB) and sleep apnea have been suggested to play an important role. Recent research has suggested a potential therapeutic benefit of adenotonsillectomy (T&A) and surgical management of upper airway obstruction in the treatment of PNE. OBJECTIVE: The aim was to conduct a systematic review of relevant literature to determine the effectiveness of T&A in treating children aged 2-19 years with PNE. STUDY DESIGN: This was a systematic review using a comprehensive electronic search strategy that included PubMed, Embase, CINAHL, Cochrane Library, conference proceedings, and the gray literature up to July 2015. We included all studies of children aged 2-19 years with PNE and SDB who underwent T&A. The primary outcome was resolution of PNE following surgery. Observational studies and randomized trials were reviewed. Risk of bias assessment and meta-analyses of included studies were performed. RESULTS: We screened 3254 citations; following title and abstract screening, 42 studies were selected for full-text screening by two independent reviewers. We included 18 studies (890 patients) in our final analysis. All studies were observational and only one included a control group. Meta-analysis of proportions of all (18) studies revealed a pooled complete resolution rate of 51% (43-60%), with significant heterogeneity among studies (I2 = 82.2%). Partial resolution was seen in 20% (14-27%), with similar heterogeneity to the complete resolution group. Sensitivity analysis including only studies with a low risk of bias and with patients ≥5 years (n = 244 patients) yielded a complete resolution rate of 43% (36-49%) with minimal heterogeneity (I2 = 0%; figure). CONCLUSION: In our systematic review, T&A resulted in improvement of nocturnal enuresis in more than 60% of patients, with complete resolution rates in excess of 50%. Findings were persistent on meta-analysis focused only on studies including older patients (≥5 years) and those with short follow-up after surgery (≤3 months), which imply a higher cure rate than would be expected based on natural history alone. The limitations of this review include the lack of controlled trials, the overall quality of the evidence reviewed and the heterogeneity between included studies. The role for systematic investigation and treatment of sleep disorders in patients with PNE should be scrutinized further, since a near 50% complete resolution rate for PNE may be expected with T&A in some settings.

A population-based study of prevalence trends and geospatial analysis of hypospadias and cryptorchidism compared with non-endocrine mediated congenital anomalies.

INTRODUCTION: Several reports have suggested an increase in the prevalence of hypospadias and cryptorchidism over the last few decades. Endocrine disruption caused by exposure to environmental chemicals has been postulated as a possible cause. OBJECTIVES: The objectives of our study were: 1) to determine whether the prevalence of hypospadias and cryptorchidism is increasing compared with other congenital anomalies not known to be mediated by endocrine factors; and 2) to perform a geospatial analysis of these congenital malformations looking for clustering that could offer insight into environmental risk factors. MATERIAL AND METHODS: Data were obtained from the Nova Scotia ATLEE Perinatal Database containing the perinatal records of all live births in Nova Scotia, Canada since 1988. Records from 1988 to 2013 defined the study cohort. Overall prevalence rates and prevalence trends by year were calculated for hypospadias, cryptorchidism, gastroschisis, and clubfoot. County of residence was collected and spatial autocorrelation testing for clustering was performed for each of the congenital anomalies. RESULTS: There were 258,147 live births during the study period. Overall prevalence rates for the four malformations over the study period were: hypospadias 78 per 10,000 male births, cryptorchidism 75 per 10,000 male births, clubfoot 24 per 10,000 total births, and gastroschisis 4 per 10,000 total births. Incidence rate ratios per year for hypospadias, cryptorchidism, clubfoot, and gastroschisis were 1.00 (0.99-1.01), 0.99 (0.98-1.00), 0.98 (0.97-0.99), and 1.04 (1.04-1.07), respectively. During the study period, the prevalence rates in the region were unchanged for hypospadias, slightly reduced for cryptorchidism and clubfoot, and rising for gastroschisis (Figure). Spatial autocorrelation testing revealed statistically significant clustering for hypospadias (p = 0.03) and cryptorchidism (p = 0.03), while no spatial autocorrelation was observed for the other malformations. DISCUSSION: Contrary to previous studies we show that hypospadias and cryptorchidism prevalence rates are not increasing over time in our region. Nonetheless, rates for these conditions in our area are high compared with other regions of the world. Local clustering of these congenital anomalies without clustering of the control, non-endocrine mediated congenital malformations supports a possible unique spatial distribution associated with environmental exposure. The hotspots identified for hypospadias and cryptorchidism are associated with intense agricultural activity. CONCLUSIONS: Our study found no increase in hypospadias and cryptorchidism prevalence over a 26-year period compared with other congenital anomalies not known to be associated with endocrine factors. Geospatial analysis supports high clustering for hypospadias and cryptorchidism in areas of intense agricultural activity.

Urological Follow-up in Adult Spina Bifida Patients: Is There an Ideal Interval?

OBJECTIVE: To establish the time to development of urological issues over time in adult spina bifida (SB) patients. MATERIALS AND METHODS: This is a retrospective study of adult patients attending a multidisciplinary adult SB clinic from 2000 to 2013. Patient age, sex, number of clinic visits, and length of follow-up were recorded. For each unique visit, presence of symptoms, type of urological issue (if any), and time lapsed since last appointment were obtained. The interval between the development of urological issues was assessed using a time-to-event analysis. RESULTS: One hundred twenty-three patients (46% male, 54% female, median age 26.8years) were followed for a median of 48 months, contributing to 586 unique clinic visits. Urological issues were identified in 109 patients (88.5%) during 267 visits (46%), and of those 21% were asymptomatic. In symptomatic patients, the median time to present with a urological issue was 12 months. Among the asymptomatic cases, 12%, 23%, and 34% had developed a urological issue at 12, 24, and 36 months of follow-up, respectively. Eighty-one percent of the urological issues seen in the clinic required some form of treatment or intervention. The treatment or intervention in 56% of asymptomatic urological issues was surgery. CONCLUSION: Most adult SB patients with urological issues are symptomatic by 2 years of follow-up; however, over time the proportion of asymptomatic patients with urological issues rises steadily, reaching a worrisome 34% at 3 years. Closer follow-up seems warranted.

Does intracytoplasmic sperm injection pose an increased risk of genitourinary congenital malformations in offspring compared to in vitro fertilization? A systematic review and meta-analysis.

PURPOSE: We systematically reviewed and performed a meta-analysis of the genitourinary congenital malformation rate after conception by intracytoplasmic sperm injection compared to in vitro fertilization. MATERIALS AND METHODS: We systematically reviewed studies to compare perinatal outcomes between children conceived by intracytoplasmic sperm injection vs in vitro fertilization. Studies showing genitourinary congenital malformation rates were included. We assessed the risk of bias, focusing on the quality of genitourinary congenital malformation reporting and analysis targeted at singletons. Meta-analysis was done using a random effects model for 3 outcomes, including overall genitourinary congenital malformation, hypospadias and cryptorchidism. Sensitivity analysis was also performed in only studies at low risk for bias. RESULTS: The initial search yielded 1,482 articles. We performed a full text review of 111 of these studies, of which 22 met inclusion criteria for systematic review. Meta-analysis of intracytoplasmic sperm injection and in vitro fertilization in 12,270 and 24,240 cases, respectively, revealed that intracytoplasmic sperm injection was associated with a significantly higher rate of overall genitourinary congenital malformation compared to in vitro fertilization (OR 1.27, 95% CI 1.02-1.59, p = 0.04). However, when including only 4 studies at low risk for bias with a total of 7,727 and 14,308 intracytoplasmic sperm injection and in vitro fertilization cases, respectively, the difference was not significant (OR 1.28, 95% CI 1.00-1.64, p = 0.05). There was no statistically significant difference in the rate of hypospadias (OR 1.21, 95% CI 0.87-1.69) or cryptorchidism (OR 1.39, 95% CI 0.97-2.00) between males conceived by intracytoplasmic sperm injection vs in vitro fertilization. On all analyses there was no significant statistical heterogeneity between studies (I(2) = 0). CONCLUSIONS: Intracytoplasmic sperm injection is associated with a slightly higher risk of genitourinary malformation in offspring than in vitro fertilization. However, when only higher quality studies were analyzed, the difference was not significant. The hypospadias and cryptorchidism rates in offspring are similar for the 2 conception methods.

A two-stage spin cartridge for integrated protein precipitation, digestion and SDS removal in a comparative bottom-up proteomics workflow.

Protein precipitation with organic solvent is an effective means of depleting contaminants such as sodium dodecyl sulfate (SDS), while maintaining high analyte recovery. Here, we report the use of a disposable two-stage spin cartridge to facilitate isolation of the precipitated protein, with subsequent enzyme digestion and peptide cleanup in the cartridge. An upper filtration cartridge retains over 95% of the protein (10 µg BSA), with 99.75% detergent depleted from a sample initially containing 2% SDS. Following precipitation, a plug attached to the base of the filtration cartridge retains the solution to enable tryptic digestion in the vial, while a solid phase extraction cartridge attached to the base of the filter facilitates peptide cleanup post-digestion. A GELFrEE fractionated Escherichia coli proteome extract processed with the spin cartridge yields similar protein identifications compared to controls (226 vs 216 for control), and with an increased number of unique peptides (1753 vs 1554 for control). The device is applied to proteome characterization of rat kidneys experiencing a surgically induced ureteral tract obstruction, revealing several statistically altered proteins, consistent with the morphology and expected pathophysiology of the disease. BIOLOGICAL SIGNIFICANCE: Conventionally, protein precipitation involves extended centrifugation to pellet the sample, with careful pipetting to remove the supernatant without disturbing the pellet. The method is not only time consuming but is highly subject to the skill of the individual, particularly at lower protein concentrations where the pellet may not be visible. As such, protein precipitation is often overlooked in proteomics, favoring column-based approaches to concentrate or purify samples. Here, all aspects of sample manipulation are integrated into a simple disposable cartridge. The device enables SDS depletion, sample preconcentration, resolubilization, derivatization, digestion, and peptide cleanup in a highly repeatable and easily multiplexed format. The device is ideally suited for comparative proteome studies. Antenatal hydronephrosis is a congenital disorder affecting 1-5% of all pregnancies, and can require surgical intervention to avoid loss of renal function. Using our device, we investigated the impact of hydronephrosis on the kidneys in a surgically induced animal model of the disease. Proteome analysis points to decreased metabolic activity in the obstructed kidney, with upregulation of proteins involved in cytoskeletal organization. This article is part of a Special Issue entitled: Protein dynamics in health and disease. Guest Editors: Pierre Thibault and Anne-Claude Gingras.

Proteomic analysis of rat proximal tubule cells following stretch-induced apoptosis in an in vitro model of kidney obstruction.

Urinary tract obstruction (UTO) is a commonly noted disorder on prenatal ultrasound that has the potential to lead to permanent loss of renal function. To study the molecular processes of the disease, an in vitro model has been developed which involves mechanical stretch of proximal tubule cells grown on flexible plates which mimics the physiological conditions during UTO. This study employs a one dimensional SDS-PAGE fractionation procedure, followed by in-gel digest and LC-MS/MS analysis in a semi-quantitative experiment using spectral counting to relatively quantify changes in protein expression following the established model of UTO. Quantitative analysis shows 317 of the 1630 identified proteins express altered abundance, with 135 increased and 182 decreased in abundance as a result of stretch. Gene ontology (GO) and KEGG annotations implicate a number of physiological processes that have been previously shown in addition to some potentially novel processes in UTO. The quantitative proteomic analysis we performed here provides a more complete characterization of changes in protein abundance as a result of stretch than previous studies, and provides a number of previously undescribed proteins in proximal tubule cells that may play a role in UTO. BIOLOGICAL SIGNIFICANCE: Urinary tract obstruction (UTO) is a commonly noted abnormality on prenatal ultrasound that can either resolve spontaneously or require surgical intervention to prevent permanent renal damage or loss of function. While targeted studies of UTO have shown a number of pathological responses in proximal tubule cells, there are currently no large-scale quantitative studies that aim to elucidate a global cellular response. This study uses a semi-quantitative approach and applies a well characterized model of UTO to determine a number of cellular processes affected by UTO simulation and identifies a number of proteins with altered abundance that have not been noted previously in UTO. This article is part of a Special Issue entitled: Can Proteomics Fill the Gap Between Genomics and Phenotypes?