Increase In Bladder Pressure Research Articles

GPER expression prevents estrogen-induced urinary retention in obese mice

Long-term administration of exogenous estrogen is known to cause urinary retention and marked, often fatal, bladder distention in both male and female mice. Estrogen-treated mice have increased bladder pressure and decreased urine flow, suggesting that urinary retention in estrogen-treated mice is due to infravesicular obstruction to urine outflow. Thus, the condition is commonly referred to as bladder outlet obstruction (BOO). Obesity can also lead to urinary retention. As the effects of estrogen are mediated by multiple receptors, including estrogen receptors ERα and ERβ and the G protein-coupled estrogen receptor (GPER), we sought to determine whether GPER plays a role in estrogen-induced BOO, particularly in the context of obesity. Wild type and GPER knockout (KO) mice fed a high-fat diet were ovariectomized or left ovary-intact (sham surgery) and supplemented with slow-release estrogen or vehicle-only pellets. Supplementing both GPER KO and wild type obese mice with estrogen for 8 weeks resulted in weight loss, splenic enlargement, and thymic atrophy, as expected. However, estrogen-treated obese GPER KO mice developed abdominal distension, debilitation, and ulceration of the skin surrounding the urogenital opening. At necropsy, these mice had prominently distended bladders and hydronephrosis. In contrast, estrogen-treated obese wild type mice only rarely displayed these signs. Our results suggest that, under conditions of obesity, estrogen induces BOO as a result of ERα-driven pathways and that GPER expression is protective against BOO.

Burst Stimulation Evokes Increased Bladder and Urethral Pressure in Patients With Sacral Neuromodulation, Indicating Potential Activation of the Autonomic Nervous System: A Pilot Study

ObjectivesCurrently, sacral neuromodulation (SNM) outcomes are often suboptimal, and changing stimulation parameters might improve SNM efficacy. Burst stimulation mimics physiological burst firing of the nervous system and might therefore benefit patients treated with SNM. The purpose of the present pilot study was to evaluate the effect of various Burst SNM paradigms on bladder and urethral pressure in patients with overactive bladder (OAB) or nonobstructive urinary retention (NOUR). Materials and MethodsThe bladder was filled to 50% of its capacity under general anesthesia in six patients with an implanted sacral lead for SNM purposes. Bladder pressure, and mid- and proximal urethral pressure were measured using conventional (Con-) SNM and various Burst SNM paradigms (10-20-40 Hz interburst frequency) with increasing amplitudes up to 5 mA for Con-SNM and 4 mA for Burst SNM. ResultsBurst SNM caused a substantial increase in both bladder and urethral pressure. In contrast, Con-SNM caused a milder increase in urethral pressure, and only one patient showed a modest increase in bladder pressure. Furthermore, the pressure increase was higher in the proximal urethra than in the midurethra using Burst-SNM, whereas Con-SNM caused comparable increases in proximal and midurethra pressure. ConclusionsBurst SNM induces bladder contraction compared with Con-SNM and induces higher pressure increases in bladder and proximal urethra than does Con-SNM in patients with OAB or NOUR, indicating a higher degree of autonomic nervous system stimulation. The observed responses could not be fully explained by the total charge of the Burst SNM paradigms, which suggests the importance of individual Burst SNM parameters, such as frequency and amplitude. Future studies should assess the feasibility and efficacy of Burst SNM in awake patients.

Optogenetic stimulation of neurons in the anterior cingulate cortex induces changes in intravesical bladder pressure and the micturition reflex

Lower urinary tract (LUT) function is controlled by the central nervous system, including higher-order cognitive brain regions. The anterior cingulate cortex (ACC) is one of these regions, but the role of its activity in LUT function remains poorly understood. In the present study, we conducted optogenetic experiments to manipulate neural activity in mouse ACC while monitoring bladder pressure to elucidate how the activity of ACC regulates LUT function. Selective optogenetic stimulation of excitatory neurons in ACC induced a sharp increase in bladder pressure, whereas activation of inhibitory neurons in ACC prolonged the interval between bladder contractions. Pharmacological manipulation of ACC also altered bladder contractions, consistent with those observed in optogenetic experiments. Optogenetic mapping of the cortical area responsible for eliciting the increase in bladder pressure revealed that stimulation to ACC showed more potent effects than the neighboring motor cortical areas. These results suggest that ACC plays a crucial role in initiating the bladder pressure change and the micturition reflex. Thus, the balance between excitation and inhibition in ACC may regulate the reflex bidirectionally.

Optogenetic urothelial cell stimulation induces bladder contractions and pelvic nerve afferent firing.

Urothelial cells, which play an essential role in barrier function, are also thought to play a sensory role in bladder physiology by releasing signaling molecules in response to sensory stimuli that act upon adjacent sensory neurons. However, it is challenging to study this communication due to the overlap in receptor expression and proximity of urothelial cells to sensory neurons. To overcome this challenge, we developed a mouse model where we can directly stimulate urothelial cells using optogenetics. We crossed a uroplakin II (UPK2) cre mouse with a mouse that expresses the light-activated cation channel channelrhodopsin-2 (ChR2) in the presence of cre expression. Optogenetic stimulation of urothelial cells cultured from UPK2-ChR2 mice initiates cellular depolarization and release of ATP. Cystometry recordings demonstrated that optical stimulation of urothelial cells increases bladder pressure and pelvic nerve activity. Increases in bladder pressure persisted, albeit to a lesser extent, when the bladder was excised in an in vitro preparation. The P2X receptor antagonist PPADS significantly reduced optically evoked bladder contractions in vivo and ex vivo. Furthermore, corresponding nerve activity was also inhibited with PPADS. Our data suggest that urothelial cells can initiate robust bladder contractions via sensory nerve signaling or contractions through local signaling mechanisms. These data support a foundation of literature demonstrating communication between sensory neurons and urothelial cells. Importantly, with further use of these optogenetic tools, we hope to scrutinize this signaling mechanism, its importance for normal micturition and nociception, and how it may be altered in pathophysiological conditions.NEW & NOTEWORTHY Urothelial cells play a sensory role in bladder function. However, it has been particularly challenging to study this communication as both sensory neurons and urothelial cells express similar sensory receptors. Here we demonstrate using an optogenetic technique, that specific urothelial stimulation alone resulted in bladder contractions. This approach will have a long-lasting impact on how we study urothelial-to-sensory neuron communication and the changes that occur under disease conditions.

Intravesical Botulinum toxin-A injection in pediatric overactive neurogenic bladder with Detrusor overactivity: Radiologic and clinical outcomes.

The neurogenic bladder is one of the most serious and painful disorders seen in pediatric urology clinics. The upper urinary tract can be impaired by increased bladder pressure. Botulinum toxin-A (BTX-A) is one of the new therapeutic interventions for this disease. Thus, this research was designed to determine the clinical as well as radiological outcomes intravesical BTX-A injections in patients with overactive neurogenic bladder with Detrusor over activity. From March 2012 to March 2019, this cohort study was conducted at Shahid Labbafinejad hospital in Tehran, Iran. Thirty-five pediatric patients with a neurogenic bladder and Detrusor overactivity who fulfilled the eligibility criteria received BTX-A injections. Demographic data, including spinal cord lesions or congenital malformations, upper and lower urinary tract nuclear scans, evidence of vesicoureteral reflux (VUR) and its severity, and hydronephrosis and 72 h voiding diary before and after intervention were all recorded. The mean ± standard deviation age of participants was 9.47 ± 4.61 years. After injection, nocturia and urination frequency as general symptoms of the overactive neurogenic bladder improved (p < 0.05). Also, the severity of hydronephrosis was decreased in 33% of patients following injection. In our study, 32 out of 35 patients had vesicoureteral reflux. Of those, there was complete resolution and downgrading of VUR in 17 (53.12%) and 13 (40.62%) respectively. In the evaluation of voiding cystourethrography (VCUG) before and after the injection, downgrading of VUR was seen in 53% of the cases. In the 99mTc-DMSA nuclear scan before and after the injection, the appearance of a new parenchymal scar and uptake reduction was not observed, which indicates the cessation of scar formation in all patients. Although Enuresis, Urgency, Frequency, Nocturia, and UUI significantly improved after injection.

Soft silicone‐based neural interface to modulate bladder function: chronic studies in awake behaving cats

Direct bladder wall stimulation has been attempted for decades to restore bladder function in people with spinal cord injury and other voiding dysfunctions. However, these efforts were limited by co‐activation of the urethra, legs and other pelvic organs at stimulus intensities that evoked bladder contractions. Neural interfaces for the detrusor muscle itself face several challenges due to its structure and the volume changes it undergoes in normal function. We designed a stretchable silicone net that can be placed around the bladder body to anchor a soft electrode array that interfaces directly with the base of bladder to generate bladder contractions.We created implantable versions of the electrode nets and tested them in chronic experiments. We implanted 5 healthy cats (4 females, 1 male) and tested them with and without anesthesia for 2‐3 months. A pressure catheter was implanted into the bladder to control volume and measure pressure.Bladder wall stimulation through various electrode configurations (monopolar, bipolar), temporal patterns (single electrode, sequential stimulation of multiple electrodes) and stimulus intensities were able to generate complete bladder emptying. In behaving cats, bladder wall stimulation at many different stimulus intensities elicited efficient voiding at physiological bladder pressures (med: 41, IQR: 27‐60 cmH2O). However, there was little relationship (r&lt;0.28) between stimulation amplitude and bladder pressure itself. Rather, stimulation amplitude had an effect on the time between stimulation onset and bladder contraction onset. At low stimulation amplitudes, there was a longer time between stimulation onset and voiding (med: 35s, IQR: 13.5‐68.2s) than occurred at higher amplitudes, which evoked more rapid voiding (med: 23s, IQR: 10‐45s). This contrasts with anesthetized tests, where stimulation at 3 ± 2 mA evoked increases in bladder pressure up to 35 cmH2O. These results suggest that stimulation of the bladder wall recruits sensory pathways leading to an urge to void, but that can be suppressed by the animals. For most of the duration of the implants, stimulation evoked functional voiding with consistent electrical stimulation thresholds. However, after several months there was a failure of an implanted bond that limited the overall duration of the implants.Chronic experiments demonstrate that these electrode nets can be used as a neural interface to generate or initiate comfortable, complete bladder emptying in awake behaving cats. Future efforts include understanding the effects of evoked sensations on voiding and improving the integrity of the bonding between the flexible conductors and the lead wire.

Closed-loop sacral neuromodulation for bladder function using dorsal root ganglia sensory feedback in an anesthetized feline model.

Overactive bladder patients suffer from a frequent, uncontrollable urge to urinate, which can lead to a poor quality of life. We aim to improve open-loop sacral neuromodulation therapy by developing a conditional stimulation paradigm using neural recordings from dorsal root ganglia (DRG) as sensory feedback. Experiments were performed in 5 anesthetized felines. We implemented a Kalman filter-based algorithm to estimate the bladder pressure in real-time using sacral-level DRG neural recordings and initiated sacral root electrical stimulation when the algorithm detected an increase in bladder pressure. Closed-loop neuromodulation was performed during continuous cystometry and compared to bladder fills with continuous and no stimulation. Overall, closed-loop stimulation increased bladder capacity by 13.8% over no stimulation (p < 0.001) and reduced stimulation time versus continuous stimulation by 57.7%. High-confidence bladder single units had a reduced sensitivity during stimulation, with lower linear trendline fits and higher pressure thresholds for firing observed during stimulation trials. This study demonstrates the utility of decoding bladder pressure from neural activity for closed-loop control of sacral neuromodulation. An underlying mechanism for sacral neuromodulation may be a reduction in bladder sensory neuron activity during stimulation. Real-time validation during behavioral studies is necessary prior to clinical translation of closed-loop sacral neuromodulation.

Computational flow analysis of a single peristaltic wave propagation in the ureter

Background and objectiveThe bladder receives the urine from the kidney and ureter. The series of peristaltic waves facilitate urine transport to the bladder. The peristaltic flow in the ureter is associated with fluid trapping and material reflux, which may cause an increase in bladder pressure. It is difficult to visualize the complex peristalsis phenomenon, in the ureter using image and radiography experiments. A numerical simulation will help in the understanding of urine bolus formation and its effect on the ureter wall. MethodsA three-dimensional computational fluid dynamic analysis is carried out to understand the flow physics associated with bolus formation and the effect of reflux on the ureter. ANSYS-CFX, a commercially available computational dynamics package is used to simulate the peristalsis. A single sinusoidal peristaltic wave traveling along a circular tube will yield the velocity, pressure, wall shear stress distributions inside the ureter. ResultsThe propagation of the peristaltic wave results in the backflow of urine near the inlet at the beginning of the flow. As the wave propagates towards the outlet, the flow rate decreases. It is observed that pressure distribution along the ureter axis will deteriorate towards the outlet. The contraction produces a very high-pressure gradient which causes the urine backflow. The trapping and the bolus formation cause a significant rise in bolus pressure, simultaneously developing negative pressure at the contraction neck. ConclusionsThe effect of peristalsis on the ureter biofluid dynamic behavior of the ureter is visualized in this study. It is established that the peristaltic contraction results in high-pressure formation at the bolus and negative pressure at the neck. It was found to be a maximum of 1.1 Pa at the bolus center and —1.13 Pa at the neck region. At the ureter pelvis junction, a higher wall shear of 0.095 Pa is observed as the wave starts to propagate. The velocity vectors show that the trapping of urine causes reflux and results in an adverse pressure gradient near the wall. A maximum pressure gradient of 485 Pa/meter was observed at the contraction of the ureter wall.

Neurokinin 2 receptor-mediated bladder and colorectal responses in aged spinal cord injured rats.

Animal proof of principle study. Bladder and bowel dysfunction are common after spinal cord injury (SCI) and in the elderly. Neurokinin 2 receptor agonists are known to produce on-demand urination and defecation in adult SCI rats. This study compared the ability of a neurokinin 2 receptor (NK2R) agonist to produce bladder and colorectal contractions in both young adult and aged SCI rats. Dignify Therapeutics and Integrated Laboratory Systems, Durham, NC USA. Bladder and colorectal pressure and voiding efficiency were measured in response to the NK2R agonist, [Lys5,Me,Leu9,Nle10]-NKA(4-10) (LMN-NKA), in anesthetized animals. The potency and efficacy of LMN-NKA was examined in young adult and aged SCI (T3 or T9 transected) rats, with young adult and aged spinal intact rats included as controls. LMN-NKA (3-300 μg/kg i.v.) produced dose-dependent increases in bladder and colorectal pressure in all anesthetized rats. No differences in the bladder or colorectal pressure responses or voiding efficiency were observed with age or after SCI. The level of SCI did not change the pharmacodynamic responses to the agonist. An NK2R agonist produced similar responses in young adult and aged SCI rats, suggesting this class of agonists could be used as a potential therapy to induce on-demand urination and defecation in aged populations, with or without SCI.

Hyperthermia, bladder pressure, and intravesical drug delivery.

469 Background: Little is known about the pharmacokinetics of intravesical chemotherapies. Various parameters can be altered including temperature, dwell time, drug concentration, and bladder pressure. Here, we hypothesize that increasing bladder pressure during instillation will improve drug delivery. Methods: An ex-vivo porcine model was developed to evaluate determinants of drug penetration into the bladder wall. Porcine bladders were suspended in isotonic saline at 37°C with a three-way Foley catheter in the bladder. Temperature probes were positioned in the extravesical bathing solution, bladder lumen, and sutured to the detrusor to ensure maintenance of desired temperatures. 2g gemcitabine in 100mL normal saline was heated to 43°C and circulated through the bladder using the Combat Bladder Recirculation System. Bladder pressures were monitored throughout each trial. After 60 minutes of dwell time, rapid dissection was performed to obtain full-thickness bladder samples from the bladder dome, posterior wall, trigone, and left and right lateral walls. Tissue was homogenized and liquid chromatography with tandem mass spectrometry (LC/MS/MS) was performed to measure gemcitabine concentration within the bladder wall. Linear regression and Pearson correlation were performed to determine the association between mean bladder pressure during instillation and drug concentration within the bladder wall. Multiple linear regression was conducted to control for bladder location and thickness. Results: Gemcitabine concentration within the bladder wall was measured 25 times across five trials. Mean gemcitabine concentration within bladder wall was 3.68 mg/g (sd 1.35). Pressure ranged from 149.8 mmHg to 277.7 mmHg (mean 194.8, sd 22.0). On univariate analysis, higher pressure was associated with increased gemcitabine concentration within the bladder wall (correlation = 0.49, p = 0.013). This result persisted after adjusting for bladder location (ß = 0.49, p = 0.006) and thickness (ß = 0.70, p = 0.03). Unstandardized regression coefficient in each of the models was 0.099 (mmHg x g)/mg, demonstrating that for each pressure increase of 10mmHg there was an associated increase in gemcitabine concentration of approximately 1 mg/g (Table). Conclusions: Data suggest that bladder pressure dramatically improves the extent of gemcitabine penetration into the bladder wall. Future research is needed to evaluate the therapeutic effect of increased gemcitabine delivery to target tissue in patients with bladder cancer. [Table: see text]

Sharpened and Mechanically Durable Carbon Fiber Electrode Arrays for Neural Recording.

Bioelectric medicine treatments target disorders of the nervous system unresponsive to pharmacological methods. While current stimulation paradigms effectively treat many disorders, the underlying mechanisms are relatively unknown, and current neuroscience recording electrodes are often limited in their specificity to gross averages across many neurons or axons. Here, we develop a novel, durable carbon fiber electrode array adaptable to many neural structures for precise neural recording. Carbon fibers (6.8 μm diameter) were sharpened using a reproducible blowtorch method that uses the reflection of fibers against the surface of a water bath. The arrays were developed by partially embedding carbon fibers in medical-grade silicone to improve durability. We recorded acute spontaneous electrophysiology from the rat cervical vagus nerve (CVN), feline dorsal root ganglia (DRG), and rat brain. Blowtorching resulted in fibers of 72.3 ± 33.5-degree tip angle with 146.8 ± 17.7 μm exposed carbon. Observable neural clusters were recorded using sharpened carbon fiber electrodes from rat CVN (41.8 μVpp), feline DRG (101.1 μVpp), and rat brain (80.7 μVpp). Recordings from the feline DRG included physiologically relevant signals from increased bladder pressure and cutaneous brushing. These results suggest that this carbon fiber array is a uniquely durable and adaptable neural recording device. In the future, this device may be useful as a bioelectric medicine tool for diagnosis and closed-loop neural control of therapeutic treatments and monitoring systems.

SPARC: Soft silicone electrode net for modulating bladder function

Bladder wall stimulation has been attempted for many decades to restore bladder function in people with spinal cord injury and other voiding dysfunctions. However, these efforts were limited by current spread to urethral structures, activation of the legs and co‐recruitment of other pelvic organs. Neural interfaces for the detrusor muscle itself face several challenges due to its unique structure and function. To directly modulate the bladder and urethra, we designed a stretchable electrode array that interfaces directly with the surface of these organs. With a stretchable electrode array that conforms to the bladder wall, we aim to create direct organ interface electrodes to stimulate and record from the bladder wall.Acute experiments in isoflurane‐anesthetized cats (n=9, 8 males, 1 female) were performed to characterize the functional and electromechanical properties of this polymer electrode. Nerve cuffs were placed bilaterally on the hypogastric and pelvic nerves to record neural activity during bladder wall stimulation. Fine wire electromyography (EMG) electrodes were placed in gluteal muscle as well as the external anal and urethral sphincters to measure current spread. A pressure catheter was placed transurethrally to record pressure and infuse saline into the bladder. Elastic electrodes were placed on the dorsal, ventral, and both lateral aspects of the bladder. In an isovolumetric bladder state, each electrode was stimulated (at amplitude: 2–8 mA, frequency: 3 – 33 Hz, pulse width: 1ms) while recording bladder pressure and compound action potentials in the instrumented nerves. To determine the mechanism of action, pelvic and hypogastric nerves were transected sequentially while measuring bladder pressure.We found that electrodes positioned near the bladder neck around the ureterovesical junction elicited the largest bladder contractions up to ~45 cmH2O while other locations such as the bladder dome generated significantly smaller contractions (~10 cmH2O). Bipolar stimulation on the bladder limited activation of the urethral sphincter and hind limbs through current spread compared to monopolar stimulation as shown by significant reduction in EMG activity with similar increases in bladder pressure. EMG recorded from the bladder wall had a directly proportional relation between frequency and volume thereby depicting detrusor muscle activity. Finally, we found that the passive mechanical effects of the silicone net around the bladder had a minimal impact (&lt; 5 cmH2O) on bladder pressure. Following nerve transection, single electrode stimulation on the ureterovesical junction resulted in smaller pressure increases compared to before transection, whereas there was no change in the pressures evoked by multi‐electrode stimulation.These soft silicone electrode nets can be used as a neural interface to generate bladder contractions in conditions where the bladder is underactive or atonic and enables continuous monitoring of detrusor EMG to monitor bladder state. Bladder wall stimulation acts through both direct‐efferent and reflex‐driven afferent mechanisms depending on stimulation location and charge.Support or Funding InformationNIH SPARC OT2OD025297

MP54-01 SOFT SILICONE ELECTRODE NET FOR MODULATING BLADDER FUNCTION

INTRODUCTION AND OBJECTIVE: Bladder wall stimulation has been attempted for many decades to restore bladder function in people with spinal cord injury and other voiding dysfunctions. However, these efforts were limited by current spread to urethral structures, activation of the legs and co-recruitment of other pelvic organs. Neural interfaces for the detrusor muscle itself face several challenges due to its unique structure and function. To directly modulate the bladder and urethra, we designed a stretchable electrode array that interfaces directly with the surface of these organs. With a stretchable electrode array that conforms to the bladder wall, we aim to create direct organ interface electrodes to stimulate and record from the bladder wall. METHODS: Acute experiments in isoflurane-anesthetized cats (n=9, 8 males, 1 female) were performed to characterize the functional and electromechanical properties of this polymer electrode. Nerve cuffs were placed bilaterally on the hypogastric and pelvic nerves to record neural activity during bladder wall stimulation. Fine wire electromyography (EMG) electrodes were placed in gluteal muscle as well as the external anal and urethral sphincters to measure current spread. A pressure catheter was placed transurethrally to record pressure and infuse saline into the bladder. Elastic electrodes were placed on the dorsal, ventral, and both lateral aspects of the bladder. In an isovolumetric bladder state, each electrode was stimulated (at amplitude: 2-8 mA, frequency: 3 -33 Hz, pulse width: 1ms) while recording bladder pressure and compound action potentials in the instrumented nerves. RESULTS: We found that electrodes positioned near the bladder neck around the ureterovesical junction elicited the largest bladder contractions up to ∼45 cmH2O while other locations such as the bladder dome generated significantly smaller contractions (∼10 cmH2O). Bipolar stimulation on the bladder limited activation of the urethral sphincter and hind limbs through current spread compared to monopolar stimulation as shown by significant reduction in EMG activity with similar increases in bladder pressure. EMG recorded from the bladder wall had a directly proportional relation between frequency and volume thereby depicting detrusor muscle activity. Finally, we found that the passive mechanical effects of the silicone net around the bladder had a minimal impact (< 5 cmH2O) on bladder pressure. CONCLUSIONS: These soft silicone electrode nets can be used as a neural interface to generate bladder contractions in conditions where the bladder is underactive or atonic and enables continuous monitoring of detrusor EMG to monitor bladder state. Source of Funding: This project is supported through NIH SPARC OT2OD025297

The effects of botulinum toxin injection on urodynamic changes in pediatric population with neurospastic bladder: First trial in Iran

BackgroundNeurogenic bladder is one of the serious, disturbing problems referred to pediatric urologic clinics. The increase in bladder pressure may damage the upper urinary tract. Anticholinergic medications have been used as the first line of complementary treatment. Regardless can be omitted, botulinum toxin (BT) was introduced as an alternative method for increasing bladder compliance. BT is a neurotoxic poison that can interfere with acetylcholine release, leading to reduced external sphincter pressure and detrusor activity. This study was established to assess urodynamic changes following BT injection among Iranian pediatric population, for the first time. MethodsThis clinical trial was conducted at Shahid Beheshti University of Medical Sciences (SBUM), Tehran, Iran, from November 2018 to January 2019 as a medical graduation dissertation. Twenty patients, previously as followings with a neurogenic bladder who met the eligibility criteria, underwent BT injection with general anesthesia using a rigid cystoscope and an endoscopic needle. Demographic data, history of anticholinergic consumption, side effects or intolerance, and the dosage of the injected BT were all recorded. The urodynamic variables during our study included: flow rate in second two, the flow time of diuresis, time of peak flow, average flow, discharged volume, maximum detrusor muscle filling pressure, maximum flow, acceleration, post-void residual volume, compliance, and cystometric bladder capacity. SPSS software version 22 was used to analyze data. The significance level was considered less than 0.05. ResultsTwenty patients who did not respond to anticholinergic medications or could not tolerate the side effects were entered the study. The mean age was 7.7 ± 2.02 years (range 5–13), and 13 (65%) of them were male. All patients received anticholinergic medications before BT injection. Discharge volume and maximum detrusor muscle filling pressure showed the most significant changes after injection (p < 0.005). However, there was no significant effect of the baseline characteristics on post-injection improvement in urodynamic results (p > 0.05). ConclusionIn this study, maximum detrusor filling pressure and discharge volume were both significantly improved. These findings motivate additional studies towards selecting better indexes for defining the clinical improvement and its relation with specific urodynamic results. Level of EvidenceTreatment study, level III.

Regenerative potential of human dental pulp stem cells in the treatment of stress urinary incontinence: In vitro and in vivo study.

ObjectivesTo evaluate the regenerative potential of human dental pulp stem cells (hDPSCs) in an animal model of stress urinary incontinence (SUI). SUI, an involuntary leakage of urine, is due to physical stress involving an increase in bladder pressure and a damage of external urethral sphincter affecting muscles and nerves. Conventional therapies can only relieve the symptoms. Human DPSCs are characterized by peculiar stemness and immunomodulatory properties and might provide an alternative tool for SUI therapy.Materials and methodsIn vitro phase: hDPSCs were induced towards the myogenic commitment following a 24 hours pre‐conditioning with 5‐aza‐2′‐deoxycytidine (5‐Aza), then differentiation was evaluated. In vivo phase: pudendal nerve was transected in female rats to induce stress urinary incontinence; then, pre‐differentiated hDPSCs were injected in the striated urethral sphincter. Four weeks later, urethral sphincter regeneration was assayed through histological, functional and immunohistochemical analyses.ResultsHuman DPSCs were able to commit towards myogenic lineage in vitro and, four weeks after cell injection, hDPSCs engrafted in the external urethral sphincter whose thickness was almost recovered, committed towards myogenic lineage in vivo, promoted vascularization and an appreciable recovery of the continence. Moreover, hDPSCs were detected within the nerve, suggesting their participation in repair of transected nerve.ConclusionsThese promising data and further investigations on immunomodulatory abilities of hDPSCs would allow to make them a potential tool for alternative therapies of SUI.

Non-Crh Glutamatergic Neurons in Barrington's Nucleus Control Micturition via Glutamatergic Afferents from the Midbrain and Hypothalamus.

Lower urinary tract symptoms (LUTS) are exceptionally common and debilitating, and they are likely caused or exacerbated by dysfunction of neural circuits controlling bladder function. An incomplete understanding of neural control of bladder function limits our ability to clinically address LUTS. Barrington's nucleus (Bar) provides descending control of bladder and sphincter function, and its glutamatergic neurons expressing corticotropin releasing hormone (BarCrh/Vglut2) are implicated in bladder control. However, it remains unclear whether this subset of Bar neurons is necessary for voiding, and the broader circuitry providing input to this control center remains largely unknown. Here, we examine the contribution to micturition behavior of BarCrh/Vglut2 neurons relative to the overall BarVglut2 population. First, we identify robust, excitatory synaptic input to Bar. Glutamatergic axons from the periaqueductal gray (PAG) and lateral hypothalamic area (LHA) intensely innervate and are functionally connected to Bar, and optogenetic stimulation of these axon terminals reliably provokes voiding. Similarly, optogenetic stimulation of BarVglut2 neurons triggers voiding, whereas stimulating the BarCrh/Vglut2 subpopulation causes bladder contraction, typically without voiding. Next, we genetically ablate either BarVglut2 or BarCrh/Vglut2 neurons and found that only BarVglut2 ablation replicates the profound urinary retention produced by conventional lesions in this region. Fiber photometry recordings reveal that BarVglut2 neuron activity precedes increased bladder pressure, while activity of BarCrh/Vglut2 is phase delayed. Finally, deleting Crh from Bar neurons has no effect on voiding and related bladder physiology. Our results help identify the circuitry that modulates Bar neuron activity and identify subtypes that may serve different roles in micturition.

Use of the extracellular matrix from the porcine esophagus as a graft for bladder enlargement

Some patients with diseases that involve increased bladder pressure or low-capacity bladders may need bladder enlargement surgery. In current techniques for bladder enlargement, autologous tissue such as small intestine or colon tissue is used to perform cystoplasties, which is far from ideal for these patients. In search of biomaterials with appropriate regeneration and safety profiles, tissue engineering has resulted in preclinical studies with acellular matrices in animal models that have yielded positive preliminary results with respect to the urothelial cell and smooth muscle repopulation; these studies have primarily been performed with matrices originating from the bladder or intestinal submucosa. The aim of the study was to assess an extracellular matrix device derived from the porcine esophagus for augmentation cystoplasty in an animal model. Seven male Wistar rats weighing 357-390g were subjected to augmentation cystoplasty with a circular segment of the acellular matrix from the porcine esophagus. Daily postoperative follow-up was performed with evaluation of changes in body weight, behavior, and wound status. During follow-up, there were no complications associated with the process. Three specimens were sacrificed at day30, and three, at day 60. Necropsy was performed, with a description of the macroscopic findings and a morphological study. Epithelialization was observed, with different stages of mucosal development in all specimens analyzed. Repopulation of smooth muscle cells, mixed inflammatory infiltrate, and vascular neoformation were identified in the matrices. The urothelium and fibers of the smooth muscle were observed inside the implanted matrix. Additional investigations in larger animal models that allow urodynamic evaluation of the bladder with the matrix implanted are needed. However, to compare the results of this study model with those reported in the literature, a matrix derived from an organ different from the bladder was used because it could prevent the use of an intestinal segment in augmentation cystoplasty. The acellular porcine esophagus matrix offers positive results regarding the repopulation of the urothelium and smooth muscle when used in augmentation cystoplasty in a murine model.

Prokinetic effects of the neurokinin NK2 receptor agonist [Lys5,MeLeu9,Nle10]-NKA(4–10) on bladder and colorectal activity in minipigs

The effects of the neurokinin NK2 receptor agonist [Lys5,MeLeu9,Nle10]-NKA(4–10) (LMN-NKA) on bladder and colorectal function were examined in minipigs. In anesthetized animals, subcutaneous (SC) administration of 30–100 μg/kg increased peak bladder and colorectal pressures. Increases in bladder and colorectal pressure were inhibited by a 15 min pretreatment with the NK2 receptor antagonist GR 159897 (1 mg/kg intravenously (IV)). Bladder and colorectal pressures were also increased after IV (0.3 μg/kg), intranasal (IN; 100 μg/kg) and sublingual administration (SL; 5 mg/kg). There was a nonsignificant trend for hypotension (16 or 12% decrease in mean arterial pressure) after 100 μg/kg SC and 0.3 μg/kg IV, respectively, but not after 100 μg/kg IN or 5 mg/kg SL. In conscious minipigs, 30–300 μg/kg SC caused a dose-related increase in defecation that was accompanied by emesis in 38% of subjects receiving 300 μg/kg. Urination was increased after 100 μg/kg SC but not lower or higher doses. The peak plasma exposure (Cmax) after 100 μg/kg SC was 123 ng/mL, and area under the curve (AUC) was 1790 min * ng/mL. Defecation response rates (~82%) were maintained after SC administration of LMN-NKA (30 μg/kg) given 3 times daily over 5 consecutive days. Defecation rates were higher after a single dose of 100 μg/kg IN compared with vehicle, but this did not reach significance. After 7–10 mg/kg SL, 83% of animals urinated and defecated, and none had emesis. The data support the feasibility of developing a convenient and well-tolerated route of administration of LMN-NKA for human use. Minipigs may be a suitable species for toxicology studies with LMN-NKA due to the relatively low rate of emesis in this species.

Computational Fluid Dynamic Modeling of Urethral Strictures

Computational fluid dynamics have paradigm shifting potential in understanding the physiological flow of fluids in the human body. This translational branch of engineering has already made an important clinical impact on the study of cardiovascular disease. We evaluated the feasibility and applicability of computational fluid dynamics to model urine flow. We prepared a computational fluid dynamics model using an idealized male genitourinary system. We created 16 hypothetical urethral stricture scenarios as a test bed. Standard parameters of urine such as pressure, temperature and viscosity were applied as well as typical assumptions germane to fluid dynamic modeling. We used ABAQUS/CAE 6.14 (Dassault Systèmes®) with a direct unsymmetrical solver with standard (FC3D8) 3D brick 8Node elements for model generation. The average flow rate in urethral stricture disease as measured by our model was 5.97 ml per second (IQR 2.2-10.9). The model predicted a flow rate of 2.88 ml per second for a single 5Fr stricture in the mid bulbar urethra when assuming all other variables constant. The model demonstrated that increasing stricture diameter and bladder pressure strongly impacted urine flow while stricture location and length, and the sequence of multiple strictures had a weaker impact. We successfully created a computational fluid dynamics model of an idealized male urethra with varied types of urethral strictures. The resultant flow rates were consistent with the literature. The accuracy of modeling increasing bladder pressure should be improved by future iterations. This technology has vast research and clinical potential.

Simultaneous Measurement of Neuronal Activity in the Pontine Micturition Center and Cystometry in Freely Moving Mice

Understanding the complex neural mechanisms controlling urinary bladder activity is an extremely important topic in both neuroscience and urology. Simultaneously recording of the bladder activity and neural activity in related brain regions will largely advance this field. However, such recording approach has long been restricted to anesthetized animals, whose bladder function and urodynamic properties are largely affected by anesthetics. In our recent report, we found that it is feasible to record bladder pressure (cystometry) and the related cortical neuron activity simultaneously in freely moving mice. Here, we aimed to demonstrate the use of this combined method in freely moving mice for recording the activity of the pontine micturition center (PMC), a more difficultly approachable small region deeply located in the brainstem and a more popularly studied hub for controlling bladder function. Interestingly, we found that the duration of urination events linearly correlated to the time course of neuronal activity in the PMC. We observed that the activities of PMC neurons highly correlated with spike-like increases in bladder pressure, reflecting bladder contractions. We also found that anesthesia evoked prominent changes in the dynamics of the Ca2+ signals in the PMC during the bladder contraction and even induced the dripping overflow incontinence due to suppression of the neural activity in the PMC. In addition, we described in details both the system for cystometry in freely moving mice and the protocols for how to perform this combined method. Therefore, this work provides a powerful approach that enables the simultaneous measurement of neuronal activity of the PMC or any other brain sites and bladder function in freely behaving mice. This approach offers a promising possibility to examine the neural mechanisms underlying neurogenic bladder dysfunction.