The mast cell stimulator compound 48/80 causes urothelium-dependent increases in murine urinary bladder contractility.

Mast cells and degranulation of preformed inflammatory mediators contribute to lower urinary tract symptoms. This study investigated pathways by which the mast cell stimulator compound 48/80 alters urinary bladder smooth muscle contractility via mast cell activation. We hypothesized that 1) mast cell degranulation causes spontaneous urinary bladder smooth muscle contractions and 2) these contractions are caused by urothelium-derived PGE2. Urothelium-intact and -denuded urinary bladder strips were collected from mast cell-sufficient (C57Bl/6) and mast cell-deficient (B6.Cg-Kitw-sh) mice to determine if compound 48/80 altered urinary bladder smooth muscle (UBSM) contractility. Electrical field stimulation was used to assess the effects of compound 48/80 on nerve-evoked contractions. Antagonists/inhibitors were used to identify prostanoid signaling pathways activated or if direct activation of nerves was involved. Compound 48/80 caused slow-developing contractions, increased phasic activity, and augmented nerve-evoked responses in both mast cell-sufficient and -deficient mice. Nerve blockade had no effect on these responses; however, they were eliminated by removing the urothelium. Blockade of P2 purinoreceptors, cyclooxygenases, or G protein signaling abolished compound 48/80 responses. However, only combined blockade of PGE2 (EP1), PGF2α (FP), and thromboxane A2 (TP) receptors inhibited compound 48/80-induced responses. Thus, the effects of compound 48/80 are urothelium dependent but independent of mast cells. Furthermore, these effects are mediated by druggable inflammatory pathways that may be used to manage inflammatory nonneurogenic bladder hyperactivity. Finally, these data strongly suggest that great care must be taken when using compound 48/80 to determine mast cell-dependent responses in the urinary bladder.NEW & NOTEWORTHY Urothelial cells are first responders to noxious contents of the urine. Our study demonstrates that the urothelium is not only a barrier but also a modulator of urinary bladder smooth muscle phasic activity and contractility independent of immune cell recruitment in response to an inflammatory insult.

Compound 48/80 increases murine bladder wall compliance independent of mast cells.

A balance between stiffness and compliance is essential to normal bladder function, and changes in the mechanical properties of the bladder wall occur in many bladder pathologies. These changes are often associated with the release of basic secretagogues that in turn drive the release of inflammatory mediators from mast cells. Mast cell degranulation by basic secretagogues is thought to occur by activating an orphan receptor, Mas-related G protein-coupled receptor B2 (Mrgprb2). We explored the effects of the putative mast cell degranulator and Mrgprb2 agonist Compound 48/80 on urinary bladder wall mechanical compliance, smooth muscle contractility, and urodynamics, and if these effects were mast cell dependent. In wild-type mice, Mrgprb2 receptor mRNA was expressed in both the urothelium and smooth muscle layers. Intravesical instillation of Compound 48/80 decreased intermicturition interval and void volume, indicative of bladder overactivity. Compound 48/80 also increased bladder compliance while simultaneously increasing the amplitude and leading slope of transient pressure events during ex vivo filling and these effects were inhibited by the Mrgprb2 antagonist QWF. Surprisingly, all effects of Compound 48/80 persisted in mast cell-deficient mice, suggesting these effects were independent of mast cells. These findings suggest that Compound 48/80 degrades extracellular matrix and increases urinary bladder smooth muscle excitability through activation of Mrgprb2 receptors located outside of mast cells. Thus, the pharmacology and physiology of Mrgprb2 in the urinary bladder is of potential interest and importance in terms of treating lower urinary tract dysfunction.

Histamine receptors rapidly desensitize without altering nerve-evoked contractions in murine urinary bladder smooth muscle.

Histamine has been implicated in urinary bladder dysfunction as an inflammatory mediator driving sensory nerve hypersensitivity. However, the direct influence of histamine on smooth muscle has not been thoroughly investigated. We hypothesized that histamine directly contracts urinary bladder smooth muscle (UBSM) independent of effects on nerves. Single cell quantitative RT-PCR determined that only histamine H1 and H2 receptors were expressed on UBSM cells. In isolated tissue bath experiments, histamine (200 µM) caused a highly variable and rapidly desensitizing contraction that was completely abolished by the H1 receptor antagonist fexofenadine (5 µM) and the Gq/11 inhibitor YM254890 (1 µM). Neither the muscarinic receptor antagonist atropine (1 µM), the Na+ channel blocker tetrodotoxin (1 µM), nor the transient receptor potential vanilloid type 1 antagonist capsazepine (10 µM) altered responses to histamine, suggesting that nerve activation was not involved. UBSM desensitization to histamine was not due to receptor internalization, as neither the cholesterol-depleting agent methyl-ß-cyclodextrin (10 mM), the dynamin-mediated endocytosis inhibitor dynasore (100 µM), nor the clathrin-mediated endocytosis inhibitor pitstop2 (15 µM) augmented or prolonged histamine contractions. Buffer from desensitized tissues still contracted histamine-naïve tissues, revealing that histamine was not metabolized. Prolonged exposure to histamine also had no effect on contractions due to electrical field stimulation, suggesting that both efferent nerve and UBSM excitability were unchanged. Together, these data suggest that histamine, although able to transiently contract UBSM, does not have a lasting effect on UBSM excitability or responses to efferent nerve input. Thus, any acute effects of histamine directly on UBSM contractility are unlikely to alter urinary bladder function.NEW & NOTEWORTHY Histamine is commonly associated with inflammatory bladder pathologies. We sought to investigate the role of histamine on urinary bladder contractility. Histamine contracts the bladder, but this response is highly variable and desensitizes completely in minutes. This desensitization is not due to internalization of the receptor or metabolism of histamine. Because nerve-evoked contractions are also not increased in the presence of histamine, our findings suggest that histamine is not directly acting to change contractility.

Development of stress-induced bladder insufficiency requires functional TRPV1 channels.

Social stress causes profound urinary bladder dysfunction in children that often continues into adulthood. We previously discovered that the intensity and duration of social stress influences whether bladder dysfunction presents as overactivity or underactivity. The transient receptor potential vanilloid type 1 (TRPV1) channel is integral in causing stress-induced bladder overactivity by increasing bladder sensory outflow, but little is known about the development of stress-induced bladder underactivity. We sought to determine if TRPV1 channels are involved in bladder underactivity caused by stress. Voiding function, sensory nerve activity, and bladder wall remodeling were assessed in C57BL/6 and TRPV1 knockout mice exposed to intensified social stress using conscious cystometry, ex vivo afferent nerve recordings, and histology. Intensified social stress increased void volume, intermicturition interval, bladder volume, and bladder wall collagen content in C57BL/6 mice, indicative of bladder wall remodeling and underactive bladder. However, afferent nerve activity was unchanged and unaffected by the TRPV1 antagonist capsazepine. Interestingly, all indices of bladder function were unchanged in TRPV1 knockout mice in response to social stress, even though corticotrophin-releasing hormone expression in Barrington's Nucleus still increased. These results suggest that TRPV1 channels in the periphery are a linchpin in the development of stress-induced bladder dysfunction, both with regard to increased sensory outflow that leads to overactive bladder and bladder wall decompensation that leads to underactive bladder. TRPV1 channels represent an intriguing target to prevent the development of stress-induced bladder dysfunction in children.

Prolonged urinary retention can and does occur after any type of ureteral reimplantantion.

OBJECTIVE: Transient urinary retention has been recognized as a complication of bilateral ureteroneocystostomy (UNC), when performed extravesically. The objective of this study was to review a collective surgeons' experiences of unilateral extra- and unilateral and/or bilateral intra-vesical ureteral reimplanation, where urinary retention greater than 6 weeks, or what we have termed, "prolonged urinary retention" (PUR), occurred. MATERIALS AND METHODS: We retrospectively reviewed charts to identify PUR after any open or robotic reimplant, other than bilateral extravesical, between 1998 and 2015 as reported by five surgeons. RESULTS: During the review period, ten cases were documented where PUR was encountered. Bilateral Cohen reimplants (5), unilateral extravesical open reimplant with ureteral tapering (3), unilateral Cohen reimplant (1) and unilateral extravesical robotic reimplant with tapering (1) were associated with PUR. Younger males predominated (70%). The mean age at operation of the patients was 3.1 years. Eventually 7/10 patients were able to void normally, with periods ranging from 6 weeks to 8 years. The remaining three patients are still unable to void more than 5 years after UNC. A majority of the samples (6/10) were suspected to have bowel and bladder dysfunction (BBD), but neurologically all were normal. CONCLUSION: PUR can occur as a potential complication following any type of UNC and is associated with the risk of significant morbidity, including permanent urinary retention. Patients and caregivers should be counseled accordingly.

Social stress in mice induces urinary bladder overactivity and increases TRPV1 channel-dependent afferent nerve activity.

Social stress has been implicated as a cause of urinary bladder hypertrophy and dysfunction in humans. Using a murine model of social stress, we and others have shown that social stress leads to bladder overactivity. Here, we show that social stress leads to bladder overactivity, increased bladder compliance, and increased afferent nerve activity. In the social stress paradigm, 6-wk-old male C57BL/6 mice were exposed for a total of 2 wk, via barrier cage, to a C57BL/6 retired breeder aggressor mouse. We performed conscious cystometry with and without intravesical infusion of the TRPV1 inhibitor capsazepine, and measured pressure-volume relationships and afferent nerve activity during bladder filling using an ex vivo bladder model. Stress leads to a decrease in intermicturition interval and void volume in vivo, which was restored by capsazepine. Ex vivo studies demonstrated that at low pressures, bladder compliance and afferent activity were elevated in stressed bladders compared with unstressed bladders. Capsazepine did not significantly change afferent activity in unstressed mice, but significantly decreased afferent activity at all pressures in stressed bladders. Immunohistochemistry revealed that TRPV1 colocalizes with CGRP to stain nerve fibers in unstressed bladders. Colocalization significantly increased along the same nerve fibers in the stressed bladders. Our results support the concept that social stress induces TRPV1-dependent afferent nerve activity, ultimately leading to the development of overactive bladder symptoms.

Social stress induces changes in urinary bladder function, bladder NGF content, and generalized bladder inflammation in mice.

Social stress may play a role in urinary bladder dysfunction in humans, but the underlying mechanisms are unknown. In the present study, we explored changes in bladder function caused by social stress using mouse models of stress and increasing stress. In the stress paradigm, individual submissive FVB mice were exposed to C57BL/6 aggressor mice directly/indirectly for 1 h/day for 2 or 4 wk. Increased stress was induced by continuous, direct/indirect exposure of FVB mice to aggressor mice for 2 wk. Stressed FVB mice exhibited nonvoiding bladder contractions and a decrease in both micturition interval (increased voiding frequency) and bladder capacity compared with control animals. ELISAs demonstrated a significant increase in histamine protein expression with no change in nerve growth factor protein expression in the urinary bladder compared with controls. Unlike stressed mice, mice exposed to an increased stress paradigm exhibited increased bladder capacities and intermicturition intervals (decreased voiding frequency). Both histamine and nerve growth factor protein expression were significantly increased with increased stress compared with control bladders. The change in bladder function from increased voiding frequency to decreased voiding frequency with increased stress intensity suggests that changes in social stress-induced urinary bladder dysfunction are context and duration dependent. In addition, changes in the bladder inflammatory milieu with social stress may be important contributors to changes in urinary bladder function.

Salvage of bilateral asynchronous perinatal testicular torsion.

PURPOSE: Current management strategies for prenatal torsion include observation alone, delayed contralateral orchiopexy and emergent contralateral orchiopexy. Bilateral torsion is now being reported with more frequency and approximately a third of these patients have asynchronous torsion. We highlight the role of scrotal exploration in neonates diagnosed with bilateral asynchronous testicular torsion. MATERIALS AND METHODS: We reviewed the clinical experience from 2000 to present of 2 senior pediatric urologists to identify cases of bilateral perinatal testicular torsion. Asynchronous torsion was identified by the varying physical findings of each testicle at exploration. A literature review was done to evaluate the evolving management of perinatal testicular torsion. RESULTS: Six cases of bilateral perinatal torsion were identified since 2000. In 3 of the 6 cases extravaginal torsion of the contralateral testis was incidentally identified at surgical exploration. All 3 testes had normal Doppler flow before exploration. Testicular salvage was not successful in the 2 patients with bilaterally absent blood flow on newborn ultrasound. The 3 cases of incidentally diagnosed contralateral torsion and 1 of preoperatively diagnosed contralateral torsion were successfully salvaged. Thus, 4 of 6 patients with bilateral torsion were left with 1 viable testis. CONCLUSIONS: Physical examination findings and radiography can be inaccurate to assess the contralateral testis in males born with prenatal torsion. We have adopted the strategy of emergent surgical exploration in cases of prenatal torsion. Using this approach anorchia was minimized in patients with bilateral asynchronous torsion.

Ipsilateral ureteroureterostomy in the surgical management of the severely dilated ureter in ureteral duplication.

PURPOSE: Ipsilateral ureteroureterostomy for the surgical management of severely dilated ureter in ureteral duplication is well supported in the surgical literature but often not done. We evaluated our institutional experience with ureteroureterostomy in duplication anomalies to assess the feasibility and success of this procedure. MATERIALS AND METHODS: An 8-year retrospective review of the records of all patients with complete renal duplex anomalies was evaluated. Anatomical presentations, and operative and nonoperative treatment of these patients were evaluated. RESULTS: A total of 193 patients were identified with complete renal duplication. Associated anomalies included ureterocele in 24 patients, ectopic ureter in 38 and vesicoureteral reflux in 57. Of 193 patients 160 (83%) with duplex anomalies underwent surgical intervention with a total of 41 ureteroureterostomies performed in 39 patients with dilated donor ureters. A total of 11 ureteroureterostomies were performed primarily and 30 were performed in conjunction with ipsilateral ureteral reimplantation of the distal common segment below the ureteroureterostomy. Ten of the 39 patients had the contralateral side reimplanted for vesicoureteral reflux. In all children with ureteroureterostomy the anastomosis between the 2 ureters remained patent. Two of the 11 children who underwent ureteroureterostomy alone had de novo ipsilateral vesicoureteral reflux (1), which was treated with ureteral reimplantation, and subureteral injection (1). Two children who underwent concomitant ureteroureterostomy and reimplantation without indwelling stents had transient postoperative urinomas that required subsequent drainage. Additionally, 3 patients had persistent ipsilateral vesicoureteral reflux, which was treated with subureteral injection in 1 and observation in 2. One patient presented with transient ipsilateral urinary obstruction, which required percutaneous drainage and resolved spontaneously. CONCLUSIONS: In cases of ureteral duplication with a severely dilated ureter requiring surgical intervention ipsilateral ureteroureterostomy is a viable option for reflux and/or obstruction. The procedure is rapid and technically feasible, and it offers excellent cosmesis. In addition, ureteroureterostomy has minimal morbidity and it facilitates early hospital discharge.

Minimally invasive open renal surgery.

PURPOSE: Improved pediatric laparoscopic techniques and instruments have led to the increased popularity of laparoscopic pyeloplasty and nephrectomy at some centers. The recent trend has compared laparoscopic to open techniques to draw parallel conclusions from the adult literature that laparoscopic surgery in children offers the same advantages. Historically open renal surgery in the pediatric population has been done successfully but usually through more traumatic incisions. We present our experience with minimally invasive open renal surgery. MATERIALS AND METHODS: A retrospective review of the last 6 years was performed of consecutive open pyeloplasties for ureteropelvic junction obstruction and open nephrectomy for multicystic dysplastic kidneys and renal duplication anomalies at a tertiary hospital for children. Parameters evaluated were patient age at surgery, surgical incision size, operative time, hospital stay and the need for postoperative narcotics. RESULTS: A total of 135 patients underwent open renal surgery using an open retroperitoneal flank incision, including 66 younger than 1, 32 who were 1 to 5, 11 who were 5 to 10 and 26 who were older than 10 years. Mean +/- SD operative time was 101.4 +/- 44.7 minutes in patients younger than 1 year, 87.7 +/- 39.3 minutes in those 1 to 5 years old, 127.1 +/- 62.7 minutes in those 5 to 10 years old and 127.8 +/- 38.4 minutes in those older than 10 years. Incision size for the groups was 1.9 +/- 0.61, 1.9 +/- 0.72, 3.0 +/- 1.3 and 3.8 +/- 1.6 cm, respectively. The last 20 patients younger than 1 year who underwent open pyeloplasty had an incision of between 1 and 1.5 cm. Most incisions were performed through a posterior, subcostal muscle splitting approach. All patients received postoperative ketorolac. Supplemental narcotics were not required in any patients younger than 10 years. Of the patients 90% were discharged home in less than 23 hours. CONCLUSIONS: The minimally invasive approach to open renal surgery is a safe and effective treatment choice in pediatric urology. The procedure can be easily performed through a small incision with minimal morbidity, comparable operative time and excellent cosmesis without excessive postoperative pain issues, allowing early discharge home. Perhaps this refined open surgery technique should be the benchmark for comparing new techniques.

Presentation of fused vas deferens.

Transverse testicular ectopia is a rare condition that usually presents as a unilateral nonpalpable testis and a contralateral descended testis with an associated hernia. Currently, with the use of diagnostic laparoscopy, transverse testicular ectopia is found before groin exploration. We reviewed 2 cases that were referred to our institution. Both patients had a common vas deferens with proximal fusion. To our knowledge, a fused vas deferens has only been reported three other times in published reports. Our second case is unique in that this is the first time a common vas deferens has been reported outside of transverse testicular ectopia.

Congenital anomalies of the kidney and urinary tract (CAKUT): a current review of cell signaling processes in ureteral development.

OBJECTIVE: The objective of this review is to present a concise summary of the genetic signaling processes involved in abnormal mouse Wolffian development and their correlation to those abnormalities affecting ureteral development in children. MATERIALS AND METHODS: We performed an extensive review of the current literature pertaining to mouse Wolffian duct development and combined these findings with our own data. CONCLUSION: This article reviews embryological findings in mice with ureteral abnormalities and draws connections between the mouse anomaly and what is seen in children. A review of the current literature has led to the identification of a number of genes which may prove to be important in understanding the causes of these anomalies.

The minimally invasive open pyeloplasty.

BACKGROUND: The dismembered pyeloplasty is the operation of choice for ureteropelvic junction obstruction (UPJO). Recently, with the advent of improved minimally invasive techniques and equipment, laparoscopic dismembered pyeloplasty has gained popularity. We present our experience with a minimally invasive open pyeloplasty. MATERIALS AND METHODS: A retrospective review of the last 5 years of consecutive open pyeloplasties was performed with regard to age, surgical operative time, length of hospital stay, need for postoperative narcotics and surgical success. RESULTS: Seventy-four patients had a dismembered pyeloplasty using an open flank incision: 34 patients (<1 year), 13 (1-5 years), 7 (5-10 years) and 20 (>10 years). Mean surgical time for patients according to age was: <1 year, 109.4+/-36.4 min; 1-5 years, 105.5+/-37.4 min; 5-10 years, 131.1+/-76.4 min; >10 years, 134+/-37.8 min. Mean incision sizes for the respective groups were 2.01+/-0.50 cm, 1.93+/-0.73 cm, 2.71+/-1.55 cm and 3.5+/-1.58 cm. The last 20 patients under 1 year of age had incisions of 1-1.5 cm. The majority of incisions were via a posterior subcostal muscle splitting approach. All patients received postoperative ketorolac and acetaminophen. Supplemental narcotics were not required in any patient less than 10 years old. All patients were discharged in <23 h. Radiologic and/or symptomatic improvement was seen in 70/74 (95%) patients after surgery. CONCLUSION: The minimally invasive approach to open pyeloplasty is a safe and effective treatment choice for UPJO. In small children our technique can be easily performed through a small incision without excessive postoperative pain allowing for early discharge. Our results with a refined open surgical technique challenge the current trend in the literature that laparoscopic pyeloplasty techniques are superior with regard to cosmesis, length of stay and postoperative narcotic use.

Abnormal dimercapto-succinic acid scans predict an increased risk of breakthrough infection in children with vesicoureteral reflux.

PURPOSE: The management of high grade vesicoureteral reflux remains controversial, with breakthrough infections being an indication for surgical repair. We sought to determine if technetium dimercapto-succinic acid (DMSA) scan could help predict which children are at risk for breakthrough urinary tract infection. MATERIALS AND METHODS: A retrospective review was performed on children presenting with a febrile urinary tract infection and prenatal hydronephrosis who were found to have vesicoureteral reflux and underwent a DMSA scan. Reflux was tabulated according to the highest grade. DMSA results were graded as 0-normal, no parenchymal or size defects, grade 1-focal parenchymal defects or less than a quarter of a renal unit involved, or grade 2-severe defects to include at least half of a renal unit, bilateral defects or unilateral atrophy. RESULTS: A total of 120 consecutive patients were evaluated. An abnormal DMSA scan was documented in 57 (33 females and 24 males), and 35 with grade 1 and 22 with grade 2 defects. Of the patients 53 females and 10 males had a normal scan. Of the 57 children with an abnormal DMSA scan 6% presented with grades 1 and 2 vesicoureteral reflux, 24% with grade 3, 38% with grade 4 and 26% with grade 5. Of the children with grades 3 to 5 reflux 60% had a subsequent breakthrough infection. Of the 63 children with a normal DMSA scan 11% presented with grade 1 reflux, 28% with grade 2, 48% with grade 3, 11% with grade 4 and 2% with grade 5. Of these children 5 had a subsequent breakthrough infection. CONCLUSIONS: An abnormality on DMSA scan in the presence of grade 3 to 5 reflux correlates with a greater chance of having a breakthrough infection (60%). We conclude that children with grade 3 to 5 vesicoureteral reflux and an abnormal DMSA scan are at increased risk for breakthrough urinary tract infection.

Children with a febrile urinary tract infection and a negative radiologic workup: factors predictive of recurrence.

OBJECTIVES: To determine the recurrence rate and risk factors for urinary tract infection (UTI) in children who present with a febrile UTI and have a negative radiologic evaluation. Febrile UTIs with no urinary tract abnormalities are a common cause of morbidity in children. METHODS: We performed a retrospective review of all children referred to our medical center after a febrile UTI. RESULTS: We reviewed 850 charts. Of 850 children, 78 had had a febrile UTI and normal ultrasound and voiding cystourography findings. Of the 78 children, 25 had had a recurrent UTI (3 boys and 22 girls). Forty-five percent of the girls with a febrile UTI developed a recurrent UTI and 14% of the boys had a recurrent UTI (P = 0.02). Three boys (two younger than 1 year of age) were uncircumcised and had one recurrent febrile UTI. Eleven (39%) of 28 girls who first presented at younger than 1 year of age and 7 (58%) of 12 girls who presented at 5 years of age or older had recurrent UTIs. The recurrence rate in the 2 to 5-year-old age group was 24% (4 of 17). Seven of the older girls exhibited symptoms of dysfunctional elimination syndrome. CONCLUSIONS: In children with a febrile UTI and a negative radiologic evaluation, recurrence was more common in girls. Boys who were uncircumcised may be at an increased risk of infection during the first year of life. In girls, the age at the time of the first infection was not predictive of recurrence. Although dysfunctional voiding and elimination may contribute to recurrent febrile UTIs in young children, an association seems to be present in children 5 years old and older.

Surgical management of the neurogenic bladder and bowel

Spina bifida and myelodysplasia are associated with neurogenic abnormalities of the bladder and bowel function. All children with myelodysplasia require an evaluation of their urinary tract with ultrasound and urodynamics to confirm normal bladder and kidney function. Patients with anatomical and functional abnormalities require treatment, the mainstay being intermittent catheterization and anticholinergic medication. The treatment goals for patients with a neurogenic bladder are the preservation of the upper urinary tract, bladder and bowel continence, independence, autonomy, and facilitation of self-esteem. A minority of children will not respond to conservative therapy and will ultimately require surgical intervention. This review will discuss the surgical options for bladder augmentation, bladder neck reconstruction and closure, as well as the methods for the creation of continent catheterizable stomas. The timing, indications, and description for each procedure will be addressed. Finally, the antegrade continence enema procedure will be described for the management of refractory fecal incontinence