Void spot assay: recommendations on the use of a simple micturition assay for mice

IFRD1 is required for maintenance of bladder epithelial homeostasis

The maintenance of homeostasis and rapid regeneration of the urothelium following stress are critical for bladder function. Here, we identify a key role for IFRD1 in maintaining urothelial homeostasis in a mouse model. We demonstrate that the murine bladder expresses IFRD1 at homeostasis, particularly in the urothelium, and its loss alters the global transcriptome with significant accumulation of endolysosomes and dysregulated uroplakin expression pattern. We show that IFRD1 interacts with mRNA-translation-regulating factors in human urothelial cells. Loss of Ifrd1 leads to disrupted proteostasis, enhanced endoplasmic reticulum (ER stress) with activation of the PERK arm of the unfolded protein response pathway, and increased oxidative stress. Ifrd1-deficient bladders exhibit urothelial cell apoptosis/exfoliation, enhanced basal cell proliferation, reduced differentiation into superficial cells, increased urothelial permeability, and aberrant voiding behavior. These findings highlight a crucial role for IFRD1 in urothelial homeostasis, suggesting its potential as a therapeutic target for bladder dysfunction.

Computational and digital analyses in the INSPIRE mouse cohort to define sex-specific functional determinants of biological aging

Biological age, which reflects the physiological state of an individual, offers a better predictive value than chronological age for age-related diseases and mortality. Nonetheless, determining accurate functional features of biological age remains challenging due to the multifactorial nature of aging. Here, we established a unique mouse cohort comprising 1576 male and female outbred SWISS mice subjected or not to high-fat, high-sucrose diet to investigate multiorgan/system biological aging throughout adulthood. Comprehensive functional and biological phenotyping at ages of 6, 12, 18, and 24 months revealed notable sex-specific disparities in longitudinal locomotion patterns and multifunctional aging parameters. Topological data analysis enabled the identification of functionally similar mouse clusters irrespective of chronological age. Moreover, our study pinpointed critical functional markers of biological aging such as muscle function, anxiety characteristics, urinary patterns, reticulocyte maturation, cardiac remodeling and function, and metabolic alterations, underscoring muscle function as an early indicator of biological age in male mice.

Polyploid superficial uroepithelial bladder barrier cells express features of cellular senescence across the lifespan and are insensitive to senolytics

Lower urinary tract dysfunction (LUTD) increases with aging. Ensuing symptoms including incontinence greatly impact quality of life, isolation, depression, and nursing home admission. The aging bladder is hypothesized to be central to this decline, however, it remains difficult to pinpoint a singular strong driver of aging-related bladder dysfunction. Many molecular and cellular changes occur with aging, contributing to decreased resilience to internal and external stressors, affecting urinary control and exacerbating LUTD. In this study, we examined whether cellular senescence, a cell fate involved in the etiology of most aging diseases, contributes to LUTD. We found that umbrella cells (UCs), luminal barrier uroepithelial cells in the bladder, show senescence features over the mouse lifespan. These polyploid UCs exhibit high cyclin D1 staining, previously reported to mediate tetraploidy-induced senescence in vitro. These senescent UCs were not eliminated by the senolytic combination of Dasatinib and Quercetin. We also tested the effect of a high-fat diet (HFD) and senescent cell transplantation on bladder function and showed that both models induce cystometric changes similar to natural aging in mice, with no effect of senolytics on HFD-induced changes. These findings illustrate the heterogeneity of cellular senescence in varied tissues, while also providing potential insights into the origin of urothelial cancer. We conclude that senescence of bladder uroepithelial cells plays a role in normal physiology, namely in their role as barrier cells, helping promote uroepithelial integrity and impermeability and maintaining the urine-blood barrier.

Therapeutic Effects of Cortex Phellodendri, Epimedium brevicornu, and Earthworm on Chronic Prostatitis/Chronic Pelvic Pain Syndrome Mice

Background:

The use of traditional Chinese medicine (TCM) for the treatment of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is widespread. The purpose of this study is to investigate the preliminary mechanism of Epimedium brevicornu Maxim., Cortex Phellodendri Chinesis (CPC), and Earthworm in the CP/CPPS model.

Methods:

Fifty C57BL/6 male mice were randomized into five groups: control, model, Epimedium brevicornu Maxim, Earthworm, and Cortex Phellodendri chinensis (CPC). To induce experimental autoimmune prostatitis (EAP), T2 peptide immune emulsion was subcutaneously injected into all groups except the control group on days 0 and 14 to induce experimental autoimmune prostatitis. Except for the control and model groups, all other groups were treated with Epimedium brevicornu Maxim., CPC, and earthworm after the successful induction of EAP.

Results:

On days 1, 28, and 56, the micturition habits and pain sensitivity of rodents in each group were evaluated. Hematoxylin-eosin (H&E) staining was used to examine prostate inflammation, whereas enzyme-linked immunosorbent assay (ELISA) was used to measure the serum level of tumor necrosis factor-α (TNF). The Epimedium brevicornu Maxim. group significantly reduced the number of urine spots and frequency of pain response compared to the model group. Epimedium brevicornu Maxim. group and CPC group significantly reduced inflammatory cell infiltration and inflammatory lesions more than Earthworm groups. The serum levels of TNF-α were substantially reduced in the Epimedium brevicornu Maxim. and CPC groups compared to the model group.

Conclusion:

Our findings showed that Epimedium brevicornu Maxim outperformed CPC and Earthworm for EAP treatment, which relieves urinary tract symptoms, enhances pain threshold, and lowers inflammation.

Nebivolol prevents redox imbalance and attenuates bladder dysfunction induced by cyclophosphamide in mice

Cyclophosphamide (CYP) is combined with cytoprotective agents to minimize its toxicity in the bladder, which is mediated by reactive oxygen species (ROS). Using multiple antioxidant mechanisms, nebivolol protects from oxidative stress in distinctive conditions. We hypothesized that nebivolol would attenuate both molecular and functional alterations induced by CYP in the bladder. Male C57BL/6 were pretreated or not with nebivolol (10 mg/kg/day, gavage), which was given 5 days before a single injection of CYP (300 mg/kg; i.p.). Molecular and functional parameters were assessed at 24 h in the bladder. Nebivolol prevented increases in ROS generation and lipoperoxidation as well as reduction of superoxide dismutase activity induced by CYP. Increased voiding frequency, decreased voiding interval, and reduced bladder capacity were found in CYP-treated mice. These responses were prevented by nebivolol. An augmented number of urinary spots and smaller urinary volumes were detected in CYP-injected mice, and nebivolol partially prevented these responses. The reduction of ROS levels is the primary mechanism by which nebivolol attenuates the deleterious effects of CYP in the bladder. The association of nebivolol with other cytoprotective agents could be an option to prevent CYP-associated oxidative damage to the bladder during chemotherapy.

Research and progress on the mechanism of lower urinary tract neuromodulation: a literature review

The storage and periodic voiding of urine in the lower urinary tract are regulated by a complex neural control system that includes the brain, spinal cord, and peripheral autonomic ganglia. Investigating the neuromodulation mechanisms of the lower urinary tract helps to deepen our understanding of urine storage and voiding processes, reveal the mechanisms underlying lower urinary tract dysfunction, and provide new strategies and insights for the treatment and management of related diseases. However, the current understanding of the neuromodulation mechanisms of the lower urinary tract is still limited, and further research methods are needed to elucidate its mechanisms and potential pathological mechanisms. This article provides an overview of the research progress in the functional study of the lower urinary tract system, as well as the key neural regulatory mechanisms during the micturition process. In addition, the commonly used research methods for studying the regulatory mechanisms of the lower urinary tract and the methods for evaluating lower urinary tract function in rodents are discussed. Finally, the latest advances and prospects of artificial intelligence in the research of neuromodulation mechanisms of the lower urinary tract are discussed. This includes the potential roles of machine learning in the diagnosis of lower urinary tract diseases and intelligent-assisted surgical systems, as well as the application of data mining and pattern recognition techniques in advancing lower urinary tract research. Our aim is to provide researchers with novel strategies and insights for the treatment and management of lower urinary tract dysfunction by conducting in-depth research and gaining a comprehensive understanding of the latest advancements in the neural regulation mechanisms of the lower urinary tract.

Automated identification and segmentation of urine spots based on deep-learning

Micturition serves an essential physiological function that allows the body to eliminate metabolic wastes and maintain water-electrolyte balance. The urine spot assay (VSA), as a simple and economical assay, has been widely used in the study of micturition behavior in rodents. However, the traditional VSA method relies on manual judgment, introduces subjective errors, faces difficulty in obtaining appearance time of each urine spot, and struggles with quantitative analysis of overlapping spots. To address these challenges, we developed a deep learning-based approach for the automatic identification and segmentation of urine spots. Our system employs a target detection network to efficiently detect each urine spot and utilizes an instance segmentation network to achieve precise segmentation of overlapping urine spots. Compared with the traditional VSA method, our system achieves automated detection of urine spot area of micturition in rodents, greatly reducing subjective errors. It accurately determines the urination time of each spot and effectively quantifies the overlapping spots. This study enables high-throughput and precise urine spot detection, providing important technical support for the analysis of urination behavior and the study of the neural mechanism underlying urination.

The mouse Social Frailty Index (mSFI): a novel behavioral assessment for impaired social functioning in aging mice

Various approaches exist to quantify the aging process and estimate biological age on an individual level. Frailty indices based on an age-related accumulation of physical deficits have been developed for human use and translated into mouse models. However, declines observed in aging are not limited to physical functioning but also involve social capabilities. The concept of "social frailty" has been recently introduced into human literature, but no index of social frailty exists for laboratory mice yet. To fill this gap, we developed a mouse Social Frailty Index (mSFI) consisting of seven distinct assays designed to quantify social functioning which is relatively simple to execute and is minimally invasive. Application of the mSFI in group-housed male C57BL/6 mice demonstrated a progressively elevated levels of social frailty through the lifespan. Conversely, group-housed females C57BL/6 mice manifested social frailty only at a very old age. Female mice also showed significantly lower mSFI score from 10 months of age onward when compared to males. We also applied the mSFI in male C57BL/6 mice under chronic subordination stress and in chronic isolation, both of which induced larger increases in social frailty compared to age-matched group-housed males. Lastly, we show that the mSFI is enhanced in mouse models that show accelerated biological aging such as progeroid Ercc1-/Δ and Xpg-/- mice of both sexes compared to age matched littermate wild types. In summary, the mSFI represents a novel index to quantify trajectories of biological aging in mice and may help elucidate links between impaired social behavior and the aging process.

Characterization and Therapeutic Potential of Curcumin-Loaded Cerium Oxide Nanoparticles for Interstitial Cystitis Management

Oxidative stress resulting from reactive oxygen species (ROS) is often considered to be the leading cause of interstitial cystitis (IC), which is a chronic inflammatory disease. Antioxidants have been proven to have promising therapeutic effects on IC. In this study, we present an antioxidant intervention for IC by introducing curcumin-loaded cerium oxide nanoparticles (Cur-CONPs). Recognizing oxidative stress as the primary contributor to IC, our research builds on previous work utilizing cerium oxide nanoparticles (CONPs) for their outstanding antioxidant and anti-inflammatory properties. However, given the need to effectively relieve acute inflammation, we engineered Cur-CONPs to harness the short-term radical-scavenging antioxidant prowess of curcumin. Through in vitro studies, we demonstrate that the Cur-CONPs exhibit not only robust antioxidant capabilities but also superior anti-inflammatory properties over CONPs alone. Furthermore, in vivo studies validate the therapeutic effects of Cur-CONPs on IC. Mice with IC subjected to the Cur-CONP treatment exhibited improved micturition behaviors, relief from pelvic pain sensitivity, and reduced expression of inflammatory proteins (IL-6, IL-1β, TNF-α, Cox2). These findings suggest that the synergistic antioxidant properties of the Cur-CONPs that combine the sustained antioxidant properties of CONPs and acute anti-inflammatory capabilities of curcumin hold promise as a novel treatment strategy for IC.

CCR2+ monocytes/macrophages drive steroid hormone imbalance-related prostatic fibrosis

Benign Prostatic Hyperplasia (BPH) is a complex condition leading to Lower Urinary Tract Symptoms in aging men, characterized by cellular proliferation, smooth muscle dysfunction, inflammation, and fibrosis. While BPH is known to involve heightened macrophage infiltration, the specific contribution of infiltrating monocytes/macrophages to the disease mechanism remains uncertain. This research explores the impact of reducing circulating monocytes and subsequently limiting their tissue infiltration by using Ccr2 knockout (Ccr2-KO) mice. Ccr2-KO and wild type mice were implanted with testosterone and estradiol (T + E2, 25 mg + 2.5 mg) pellets. Urinary function was assessed via weekly void spot assays over 12 weeks, and prostatic macrophage levels were visualized and quantified in tissue sections using an F4/80 antibody. Additionally, Ki-67 staining was used to evaluate cell proliferation, and picrosirius red staining to assess collagen accumulation. Increased voiding frequency which developed in T + E2 mice, was significantly ameliorated in Ccr2-KO mice, however, both Ccr2-KO and wild type (WT) mice showed increased bladder weights after three month, representing a hypertrophic response to bladder outlet obstruction. T + E2 substantially increased the density of macrophages in WT but not Ccr2-KO mouse prostate. Proliferation rate, as indicated by Ki-67 positivity, was elevated in the vental and anterior prostate lobes but was only marginally reduced in Ccr2-KO mice. Most importantly, a significant prostatic collagen accumulation was observed in WT mice that was markedly reduced by Ccr2 deficiency post T + E2 treatment. The absence of Ccr2 mitigates urinary dysfunction and alters prostatic macrophage levels and collagen accumulation in steroid hormone imbalance. These findings suggest a crucial role for monocyte infiltration, giving rise to macrophages or other cell derivatives, to drive fibrosis.

Neuromodulation Improves Stress Urinary Incontinence-Like Deficits in Female Rabbits

Objective: Stress urinary incontinence (SUI) affects a third of the female population and is characterized by involuntary urine leakage during abdominal efforts such as sneezing, laughing, or coughing. Acute neuromodulation of the bulbospongiosus nerve (BsN) was shown to increase bladder efficiency in aged and multiparous rabbits. This study investigates the efficacy of sub-chronic BsN neuromodulation in alleviating SUI-like deficits in mature multiparous rabbits, characterized by increased urine leakage and reduced leak point pressure. Results: Using the voiding spot assay, we observed a 40% reduction in urine leakage events after 30 days of BsN stimulation, which correlated with a 60% increase in daily micturition volume, a 10-fold increase in voided volume, and improvements in voiding efficiency and leak point pressure compared to negative control animals. Conclusion: In multiparous rabbits, BsN neuromodulation improves important SUI-like metrics including bladder capacity and urethral closure, supporting the use of this bioelectronic modality as treatment for SUI.

Circadian Rhythms Fluctuate the Treatment Effects of Intravesical Treatments on Rat Urinary Frequency Models

Objectives

It is still not clear how the intravesical instillation of drugs affects rat urinary frequency. This study aimed to examine the dynamics of intravesical treatments' treatment effect on rat urinary frequency models by real-time and extended monitoring using a novel continuous urination monitoring system.

Methods

Nine eleven-week-old female Wistar rats were divided into three groups to receive intravesical instillation of 0.1% acetic acid (AA), 1.0% AA, or phosphate-buffered saline (PBS). Thirty minutes later, these drugs were voided, and rats were moved to a continuous urination monitoring system, UM-100. UM-100 monitored rat urination quantitatively and continuously for 24 hours. Rats were then euthanized, and histopathologic examinations using a damage score validated the severity of bladder inflammation. We used nine additional rats to determine the treatment effect of various drugs against the urinary frequency. These rats were also treated with 1.0% AA in the same way and divided into three groups (n = 3 each) to receive intravesical instillation of lidocaine, silver nitrate (AgNO3), or dimethyl sulfoxide (DMSO), respectively. Thirty minutes later, rats were catheterized again and moved to the UM-100, and their voiding was monitored for 24 hours.

Results

Intravesical instillation of AA increased the urinary frequency and decreased the mean voided volume (VV) in a concentration-dependent manner, with statistical significance at a concentration of 1.0% (urinary frequency; p=0.0007, mean VV; p=0.0032, respectively) compared with PBS. Histopathological analysis of these models demonstrated a significantly higher damage score of bladder mucosa in both 0.1% AA and 1.0% AA compared with PBS, with the severity in concordance with the clinical severity of urinary frequency (0.1% AA: p < 0.0001, 1.0% AA: p < 0.0001). Moreover, intravesical instillation of lidocaine, AgNO3, and DMSO decreased the urinary frequency. Continuous monitoring with UM-100 also demonstrated that the treatment effect of these intravesically instilled drugs occurred only at night.

Conclusions

The extended monitoring of rat urination by UM-100 revealed a significant fluctuation in the treatment effect of intravesically instilled drugs between day and night. These findings may help establish novel therapies for urinary frequency.

Methylglyoxal and Advanced Glycation End Products (AGEs): Targets for the Prevention and Treatment of Diabetes-Associated Bladder Dysfunction?

Methylglyoxal (MGO) is a highly reactive α-dicarbonyl compound formed endogenously from 3-carbon glycolytic intermediates. Methylglyoxal accumulated in plasma and urine of hyperglycemic and diabetic individuals acts as a potent peptide glycation molecule, giving rise to advanced glycation end products (AGEs) like arginine-derived hydroimidazolone (MG-H1) and carboxyethyl-lysine (CEL). Methylglyoxal-derived AGEs exert their effects mostly via activation of RAGE, a cell surface receptor that initiates multiple intracellular signaling pathways, favoring a pro-oxidant environment through NADPH oxidase activation and generation of high levels of reactive oxygen species (ROS). Diabetic bladder dysfunction is a bothersome urological complication in patients with poorly controlled diabetes mellitus and may comprise overactive bladder, urge incontinence, poor emptying, dribbling, incomplete emptying of the bladder, and urinary retention. Preclinical models of type 1 and type 2 diabetes have further confirmed the relationship between diabetes and voiding dysfunction. Interestingly, healthy mice supplemented with MGO for prolonged periods exhibit in vivo and in vitro bladder dysfunction, which is accompanied by increased AGE formation and RAGE expression, as well as by ROS overproduction in bladder tissues. Drugs reported to scavenge MGO and to inactivate AGEs like metformin, polyphenols, and alagebrium (ALT-711) have shown favorable outcomes on bladder dysfunction in diabetic obese leptin-deficient and MGO-exposed mice. Therefore, MGO, AGEs, and RAGE levels may be critically involved in the pathogenesis of bladder dysfunction in diabetic individuals. However, there are no clinical trials designed to test drugs that selectively inhibit the MGO-AGEs-RAGE signaling, aiming to reduce the manifestations of diabetes-associated bladder dysfunction. This review summarizes the current literature on the role of MGO-AGEs-RAGE-ROS axis in diabetes-associated bladder dysfunction. Drugs that directly inactivate MGO and ameliorate bladder dysfunction are also reviewed here.

Targeted Delivery of Catalase and Photosensitizer Ce6 by a Tumor-Specific Aptamer Is Effective against Bladder Cancer In Vivo

Photodynamic therapy (PDT) is often applied in a clinical setting to treat bladder cancer. However, current photosensitizers report drawbacks such as low efficacy, low selectivity, and numerous side effects, which have limited the clinical values of PDT for bladder cancer. Previously, we developed the first bladder cancer-specific aptamer that can selectively bind to and be internalized by bladder tumor cells versus normal uroepithelium cells. Here, we use an aptamer-based drug delivery system to deliver photosensitizer chlorine e6 (Ce6) into bladder tumor cells. In addition to Ce6, we also incorporate catalase into the drug complex to increase local oxygen levels in the tumor tissue. Compared with free Ce6, an aptamer-guided DNA nanotrain (NT) loaded with Ce6 and catalase (NT-Catalase-Ce6) can specifically recognize bladder cancer cells, produce oxygen locally, induce ROS in tumor cells, and cause mitochondrial apoptosis. In an orthotopic mouse model of bladder cancer, the intravesical instillation of NT-Catalase-Ce6 exhibits faster drug internalization and a longer drug retention time in tumor tissue compared with that in normal urothelium. Moreover, our modified PDT significantly inhibits tumor growth with fewer side effects such as cystitis than free Ce6. This aptamer-based photosensitizer delivery system can therefore improve the selectivity and efficacy and reduce the side effects of PDT treatment in mouse models of bladder cancer, bearing a great translational value for bladder cancer intravesical therapy.

TRPA1 channel mediates methylglyoxal-induced mouse bladder dysfunction

Introduction: The transient receptor potential ankyrin 1 channel (TRPA1) is expressed in urothelial cells and bladder nerve endings. Hyperglycemia in diabetic individuals induces accumulation of the highly reactive dicarbonyl compound methylglyoxal (MGO), which modulates TRPA1 activity. Long-term oral intake of MGO causes mouse bladder dysfunction. We hypothesized that TRPA1 takes part in the machinery that leads to MGO-induced bladder dysfunction. Therefore, we evaluated TRPA1 expression in the bladder and the effects of 1 h-intravesical infusion of the selective TRPA1 blocker HC-030031 (1 nmol/min) on MGO-induced cystometric alterations. Methods: Five-week-old female C57BL/6 mice received 0.5% MGO in their drinking water for 12 weeks, whereas control mice received tap water alone. Results: Compared to the control group, the protein levels and immunostaining for the MGO-derived hydroimidazolone isomer MG-H1 was increased in bladders of the MGO group, as observed in urothelium and detrusor smooth muscle. TRPA1 protein expression was significantly higher in bladder tissues of MGO compared to control group with TRPA1 immunostaining both lamina propria and urothelium, but not the detrusor smooth muscle. Void spot assays in conscious mice revealed an overactive bladder phenotype in MGO-treated mice characterized by increased number of voids and reduced volume per void. Filling cystometry in anaesthetized animals revealed an increased voiding frequency, reduced bladder capacity, and reduced voided volume in MGO compared to vehicle group, which were all reversed by HC-030031 infusion. Conclusion: TRPA1 activation is implicated in MGO-induced mouse overactive bladder. TRPA1 blockers may be useful to treat diabetic bladder dysfunction in individuals with high MGO levels.

Aging and urinary control: Alterations in the brain-bladder axis

Age-associated alterations in bladder control affect millions of older adults, with a heavy burden added to families both economically and in quality of life. Therapeutic options are limited with poor efficacy in older adults, lending to a growing need to address the gaps in our current understanding of urinary tract aging. This review summarizes the current knowledge of age-associated alterations in the structure and function of the brain-bladder axis and identifies important gaps in the field that have yet to be addressed. Urinary aging is associated with decreased tissue responsiveness, decreased control over the voiding reflex, signaling dysfunction along the brain-bladder axis, and structural changes within the bladder wall. Studies are needed to improve our understanding of how age affects the brain-bladder axis and identify genetic targets that correlate with functional outcomes.

Polychlorinated biphenyl (PCB) exposure in adult female mice can influence bladder contractility

Lower urinary tract symptoms (LUTS) greatly reduce quality of life. While LUTS etiology is not completely understood, it is plausible that environmental contaminants could play a role. Polychlorinated biphenyls (PCBs), are a group of persistent environmental toxicants frequently documented in animal and human tissues. PCBs are capable of influencing voiding function in mouse offspring exposed developmentally, however whether PCB exposure during adulthood can also influence voiding dynamics is unknown. Therefore, the purpose of this study was to determine whether PCB exposure in adult female mice can impact voiding function. As part of a larger study to generate developmentally exposed offspring, adult female C57Bl/6J mice were dosed orally with the MARBLES PCB mixture (0.1, 1, or 6 mg/kg/day) or vehicle control beginning two weeks before mating and throughout gestation and lactation (9 weeks). Adult dosed female dams then underwent void spot assay, uroflowmetry, and anesthetized cystometry to assess voiding function. Bladder contractility was assessed in ex vivo bladder bath assays, and bladders were collected for morphology and histology assessments. While voiding behavior endpoints were minimally impacted, alterations to bladder contractility dynamics were more pronounced. Adult female mice dosed with 1 mg/kg/d PCB showed an increase in urine spots 2-3 cm2 in size, increased bladder contractility in response to electrical field stimulation, and decreased bladder wall thickness compared to vehicle control. PCBs also altered contractile response to cholinergic agonist in a dose-dependent manner. Overall, these results indicate that exposure to PCBs in adult female mice is sufficient to produce changes in bladder physiology. These results also highlight the critical role of timing of exposure in influencing voiding function.

Evidence that methylglyoxal and receptor for advanced glycation end products are implicated in bladder dysfunction of obese diabetic ob/ob mice

Glycolytic overload in diabetes causes large accumulation of the highly reactive dicarbonyl compound methylglyoxal (MGO) and overproduction of advanced glycation end products (AGEs), which interact with their receptors (RAGE), leading to diabetes-associated macrovascular complications. The bladder is an organ that stays most in contact with dicarbonyl species, but little is known about the importance of the MGO-AGEs-RAGE pathway to diabetes-associated bladder dysfunction. Here, we aimed to investigate the role of the MGO-AGEs-RAGE pathway in bladder dysfunction of diabetic male and female ob/ob mice compared with wild-type (WT) lean mice. Diabetic ob/ob mice were treated with the AGE breaker alagebrium (ALT-711, 1 mg/kg) for 8 wk in drinking water. Compared with WT animals, male and female ob/ob mice showed marked hyperglycemia and insulin resistance, whereas fluid intake remained unaltered. Levels of total AGEs, MGO-derived hydroimidazolone 1, and RAGE in bladder tissues, as well as fluorescent AGEs in serum, were significantly elevated in ob/ob mice of either sex. Collagen content was also markedly elevated in the bladders of ob/ob mice. Void spot assays in filter paper in conscious mice revealed significant increases in total void volume and volume per void in ob/ob mice with no alterations of spot number. Treatment with ALT-711 significantly reduced the levels of MGO, AGEs, RAGE, and collagen content in ob/ob mice. In addition, ALT-711 treatment normalized the volume per void and increased the number of spots in ob/ob mice. Activation of AGEs-RAGE pathways by MGO in the bladder wall may contribute to the pathogenesis of diabetes-associated bladder dysfunction.NEW & NOTEWORTHY The involvement of methylglyoxal (MGO) and advanced glycation end products (AGEs) in bladder dysfunction of diabetic ob/ob mice treated with the AGE breaker ALT-711 was investigated here. Diabetic mice exhibited high levels of MGO, AGEs, receptor for AGEs (RAGE), and collagen in serum and/or bladder tissues along with increased volume per void, all of which were reduced by ALT-711. Activation of the MGO-AGEs-RAGE pathway in the bladder wall contributes to the pathogenesis of diabetes-associated bladder dysfunction.

Minimizing the variables of voiding spot assay for comparison between laboratories

The voiding spot assay (VSA) is increasingly being adopted as a standard method for assessing mouse urinary function. However, VSA outcomes are highly sensitive to housing environment and procedural parameters. Many variables exist among laboratories, including analytical software, type of daily housing cage, transportation, and the time of the day. Some of these variables, such as the time of VSA and analytical software, have been shown to result in inconsistency and incomparability of data. In this study, we evaluated whether the results of VSA can be compared across laboratories by minimizing these variables. We found that analytical tools between Fiji and MATLAB are in good agreement in the quantification of VSA parameters, especially primary voiding spot (PVS) parameters. Unexpectedly, we found that mice housed in different daily home cages did not alter voiding patterns in a standard VSA cage. Nonetheless, we still recommend acclimation when performing VSA in unfamiliar cages. Notably, mice are highly sensitive to transportation and the time in the morning versus afternoon, which can induce significant changes in voiding patterns. Therefore, a standardized period among laboratories and allowing 2-3 days of rest for mice acclimation after transportation are necessary for VSA. Finally, we performed VSA using identical procedural parameters in two laboratories from two geographical locations to compare the results of VSA and concluded that it is possible to generate limited comparable VSA data, such as PVS volume.

Prevention of Radiation-Induced Bladder Injury: A Murine Study Using Captopril

PURPOSE

Pelvic radiation therapy (RT) can cause debilitating bladder toxicities but few clinical interventions exist to prevent injury or alleviate symptoms. From a large genome-wide association study in patients with prostate cancer it was previously reported that SNPs tagging AGT, part of the renin-angiotensin system (RAS), correlated with patient-reported late hematuria, identifying a potential targetable pathway to prevent RT-induced bladder injury. To investigate this association, we performed a preclinical study to determine whether RAS modulation protected the bladder against RT injury.

METHODS AND MATERIALS

C57BL/6 male mice were treated with an oral angiotensin converting enzyme inhibitor (ACEi: 0.3g/L captopril) 5 days before focal bladder X-irradiation with either single dose (SD) 30 Gy or 3 fractions of 8 Gy (8 Gy × 3 in 5 days). RT was delivered using XStrahl SARRP Muriplan CT-image guidance with parallel-opposed lateral beams. ACEi was maintained for 20 weeks post RT. Bladder toxicity was assessed using assays to identify local injury that included urinalysis, functional micturition, bladder-released exosomes, and histopathology, as well as an assessment of systemic changes in inflammatory-mediated circulating immune cells.

RESULTS

SD and fractionated RT increased urinary frequency and reduced the volume of individual voids at >14 weeks, but not at 4 weeks, compared with nonirradiated animals. Urothelial layer width was positively correlated with mean volume of individual voids (P = .0428) and negatively correlated with number of voids (P = .028), relating urothelial thinning to changes in RT-mediated bladder dysfunction. These chronic RT-induced changes in micturition patterns were prevented by captopril treatment. Focal bladder irradiation significantly increased the mean particle count of urine extracellular vesicles and the monocyte and neutrophil chemokines CCL2 and MIP-2, and the proportions of circulating inflammatory-mediated neutrophils and monocytes, which was also prevented by captopril. Exploratory transcriptomic analysis of bladder tissue implicated inflammatory and erythropoietic pathways.

CONCLUSIONS

This study demonstrated that systemic modulation of the RAS protected against and alleviated RT-induced late bladder injury but larger confirmatory studies are needed.

Toxicoproteomics of Mono(2-ethylhexyl) phthalate and Perfluorooctanesulfonic Acid in Models of Prostatic Diseases

Benign and malignant prostatic diseases are common, costly, and burdensome; moreover, they share fundamental underlying molecular processes. Several ubiquitous contaminants may perturb these processes, possibly via peroxisome proliferator-activated receptor (PPAR) signaling, but the role of environmental exposures─particularly mixtures─in prostatic diseases is undefined. In the present study, nontumorigenic prostate stromal cells and metastatic prostate epithelial cells were exposed to ubiquitous exogenous PPAR ligands under different dosing paradigms, including a mixture, and effects were assessed via mass spectrometry-based global proteomics. In prostate stromal cells, environmentally relevant levels of mono(2-ethylhexyl) phthalate (MEHP), alone and in combination with perfluorooctanesulfonic acid, led to significant changes in proteins involved in key processes underlying prostatic diseases: oxidative stress defense, proteostasis, damage-associated molecular pattern signaling, and innate immune response signaling. A follow-up experiment in metastatic prostate epithelial cells showed that the occupationally relevant levels of MEHP perturbed similar processes, including lipid, cholesterol, steroid, and alcohol metabolism; apoptosis and coagulation regulation; wound response; and aging. This work shows that environmental exposures may contribute to prostatic diseases by perturbing key processes of a proposed adverse outcome pathway, including lipid metabolism, oxidative stress, and inflammation. Future in vivo research will investigate the role of contaminants in prostatic diseases and in preventative agents.

Establishment of an overactive bladder model in mice

BACKGROUND

Overactive bladder (OAB) is a syndrome characterized by symptoms of urinary urgency, often accompanied by frequent urination and nocturia or urge incontinence.

METHODS

Twenty female ICR mice were randomly divided into pBOO (partial bladder outlet obstruction) and control groups. The mouse OAB model was constructed by ligating the bladder outlet. Eight weeks after the operation, the methods of voiding spot on paper (VSOP), isolated detrusor muscle, and HE staining were used for analysis and research.

RESULTS

After the operation, two mice in the experimental and one in control died, and one in the control groups had an abnormal bladder size, so it was excluded from the statistical analysis. Eight weeks after the operation, there was an insignificant difference (P = 0.15) in the body weight of mice in the pBOO (26.54 ± 2.62 g) and the control group (24.84 ± 1.76 g). The number of urinations in 12 h was significantly higher (P < 0.001) in the pBOO (7.63 ± 1.19) than in the control group (4.13 ± 0.99). Also, the 12-h urine volume of pBOO (1491.23 ± 94.72 μL) was significantly greater (P = 0.006) than that of the control group (1344.86 ± 88.17 μL). The isolated bladder of the pBOO mice was significantly heavier than that in the control group (53.16 ± 1.79 mg vs. 24.54 ± 1.80 mg, P < 0.001), the horizontal and vertical length of the bladder in pBOO group were larger than those in the control group (P < 0.001). The detrusor thickness of pBOO group (357.50 ± 11.88 µm) was significantly thicker than that of control group (258.52 ± 17.22 µm, P < 0.001), and the isolated muscle strip was more sensitive to carbachol stimulation. According to HE staining, the bladder wall of the pBOO mice was significantly thickened.

CONCLUSIONS

A pBOO-mediated mouse OAB model was successfully established by ligating the bladder outlet.

Real-Time Void Spot Assay

Normal voiding behavior is the result of the coordinated function of the bladder, the urethra, and the urethral sphincters under the proper control of the nervous system. To study voluntary voiding behavior in mouse models, researchers have developed the void spot assay (VSA), a method that measures the number and area of urine spots deposited on a filter paper lining the floor of an animal's cage. Although technically simple and inexpensive, this assay has limitations when used as an end-point assay, including a lack of temporal resolution of voiding events and difficulties quantifying overlapping urine spots. To overcome these limitations, we developed a video-monitored VSA, which we call real-time VSA (RT-VSA), and which allows us to determine voiding frequency, assess voided volume and voiding patterns, and make measurements over 6 h time windows during both the dark and light phases of the day. The method described in this report can be applied to a wide variety of mouse-based studies that explore the physiological and neurobehavioral aspects of voluntary micturition in health and disease states.

The impact of short term, long term and intermittent E. coli infection on male C57BL/6J mouse prostate histology and urinary physiology

Prostatic inflammation and prostatic fibrosis are associated with lower urinary tract dysfunction in men. Prostatic inflammation arising from a transurethral uropathogenic E. coli infection is sufficient to increase prostatic collagen content in male mice. It is not known whether and how the sequence, duration and chronology of prostatic infection influence urinary function, prostatic inflammation and collagen content. We placed a transurethral catheter into adult male C57BL/6J mice to deliver uropathogenic E. coli UTI189 two-weeks prior to study endpoint (to evaluate the short-term impact of infection), 10-weeks prior to study endpoint (to evaluate the long-term impact of infection), or two-, six-, and ten-weeks prior to endpoint (to evaluate the impact of repeated intermittent infection). Mice were catheterized the same number of times across all experimental groups and instilled with sterile saline when not instilled with E. coli to control for the variable of catheterization. We measured bacterial load in free catch urine, body weight and weight of bladder and dorsal prostate; prostatic density of leukocytes, collagen and procollagen 1A1 producing cells, and urinary function. Transurethral E. coli instillation caused more severe and persistent bacteriuria in mice with a history of one or more transurethral instillations of sterile saline or E. coli. Repeated intermittent infections resulted in a greater relative bladder wet weight than single infections. However, voiding function, as measured by the void spot assay, and the density of collagen and ProCOL1A1+ cells in dorsal prostate tissue sections did not significantly differ among infection groups. The density of CD45+ leukocytes was greater in the dorsal prostate of mice infected two weeks prior to study endpoint but not in other infection groups compared to uninfected controls.

Inhibition of hypoxia-inducible factor-prolyl hydroxylation protects from cyclophosphamide-induced bladder injury and urinary dysfunction

Disruption of the blood-urine barrier can result in acute or chronic inflammatory bladder injury. Activation of the oxygen-regulated hypoxia-inducible factor (HIF) pathway has been shown to protect mucosal membranes by increasing the expression of cytoprotective genes and by suppressing inflammation. The activity of HIF is controlled by prolyl hydroxylase domain (PHD) dioxygenases, which have been exploited as therapeutic targets for the treatment of anemia of chronic kidney disease. Here, we established a mouse model of acute cyclophosphamide (CYP)-induced blood-urine barrier disruption associated with inflammation and severe urinary dysfunction to investigate the HIF-PHD axis in inflammatory bladder injury. We found that systemic administration of dimethyloxalylglycine or molidustat, two small-molecule inhibitors of HIF-prolyl hydroxylases, profoundly mitigated CYP-induced bladder injury and inflammation as assessed by morphological analysis of transmural edema and urothelial integrity and by measuring tissue cytokine expression. Void spot analysis to examine bladder function quantitatively demonstrated that HIF-prolyl hydroxylase inhibitor administration normalized micturition patterns and protected against CYP-induced alteration of urinary frequency and micturition patterns. Our study highlights the therapeutic potential of HIF-activating small-molecule compounds for the prevention or therapy of bladder injury and urinary dysfunction due to blood-urine barrier disruption.NEW & NOTEWORTHY Disruption of the blood-urine barrier can result in acute or chronic inflammatory bladder injury. Here, we demonstrate that pharmacological inhibition of hypoxia-inducible factor (HIF)-prolyl hydroxylation prevented bladder injury and protected from urinary dysfunction in a mouse model of cyclophosphamide-induced disruption of the blood-urine barrier. Our study highlights a potential role for HIF-activating small-molecule compounds in the prevention or therapy of bladder injury and urinary dysfunction and provides a rationale for future clinical studies.

Cuprizone-mediated demyelination reversibly degrades voiding behavior in mice while sparing brainstem reflex

Multiple sclerosis (MS) is a chronic, progressively debilitating demyelinating disease of the central nervous system (CNS). Nearly 80% of MS patients experience lower urinary tract dysfunction early in their diagnosis. This significantly affects the quality of life, and in latter stages of disease is a leading cause of hospitalization. Previously, animal models have shown that inflammatory demyelination in the CNS causes profound bladder dysfunction, but the confounding influence of systemic inflammation limits the potential interpretation of the contribution of CNS demyelination to bladder dysfunction. Since the micturition circuit has myelinated neuronal connections in the cortex, brainstem, and spinal cord, we examined alterations in bladder function in the cuprizone model characterized by demyelinating lesions in the cortex and corpus callosum that are independent of T-cell-mediated autoimmunity. Herein, we report that a 4-week dietary cuprizone treatment in C57Bl/6J mice induced alterations in voiding behavior with increased micturition frequency and reduced volume voided, similar to human MS bladder dysfunction. Subsequently, recovery from cuprizone treatment restored normal bladder function. Demyelination and remyelination were confirmed by Luxol Fast Blue staining of the corpus callosum. Additionally, we also determined that an 8-week cuprizone treatment, resulting in chronic demyelination lacking spontaneous remyelination potential, is associated with an exacerbated voiding phenotype. Interestingly, while cuprizone-induced CNS demyelination severely affected conscious (cortical) urinary behavior, the brainstem and spinal cord reflex remained unchanged, as confirmed by urethane-anesthetized cystometry. This is the first study to show that cortical demyelination independent of inflammation can negatively impact urinary function.

Increased extracellular matrix stiffness accompanies compromised bladder function in a murine model of radiation cystitis

Radiation cystitis, a long-term bladder defect due to pelvic radiation therapy, results in lower urinary tract symptoms, such as urinary frequency and nocturia, suggestive of compromised bladder compliance. The goal of this study was to identify alterations to the mechanical behavior of the urinary bladder extracellular matrix of a murine model of radiation cystitis, at 3 and 6 months after radiation exposure. The results of this study demonstrated that the extracellular matrix of irradiated bladders was significantly less distensible when compared to age matching controls. These findings coincided with functional bladder changes, including increased number of voids and decreased voided volume. Both mechanical and functional changes were apparent at 3 months post-irradiation and were statistically significant at 6 months, demonstrating the progressive nature of radiation cystitis. Overall, the results of this study indicate that irradiation exposure changes both the mechanical and physiological properties of the bladder. STATEMENT OF SIGNIFICANCE: In humans, radiation cystitis results in lower urinary tract symptoms, such as urinary frequency and nocturia, suggestive of compromised bladder compliance. This pathology can significantly affect recovery and quality of life for cancer survivors. Gaining knowledge about how alterations to the mechanical behavior of the urinary bladder extracellular matrix can affect urinary function will have a significant impact on this population. The results of this study demonstrated that the extracellular matrix of irradiated bladders was significantly less distensible when compared to age matching controls, in a mouse model of radiation cystitis. These findings were accompanied by functional voiding changes, including increased number of voids and decreased voided volume. The results of this study uncovered that irradiation exposure changes the mechanical and physiological properties of the bladder.

FimH confers mannose-targeting ability to Bacillus Calmette-Guerin for improved immunotherapy in bladder cancer

BACKGROUND

Bladder cancer is a common disease worldwide with most patients presenting with the non-muscle-invasive form (NMIBC) at initial diagnosis. Postoperational intravesical instillation of BCG is carried out for patients with high-risk disease to reduce tumor recurrence and progression to muscle invasive disease. However, BCG can also have side effects or be ineffective in some patients because it cannot enter the cancer cells. Thus, to improve the efficacy of BCG immunotherapy is the long-term pursuit of the bladder cancer field.

METHODS

To increase the adhesion of BCG to the urothelium we overexpressed FimH, a mannose binding protein naturally used by uropathogenic Escherichia coli to adhere to human urothelium, onto the surface of BCG. The adhesion/internalization ability of rBCG-S.FimH was examined in mouse bladder by fluorescence microscopy. Preclinical evaluation of antitumor efficacy was carried out in orthotopic mouse models of bladder cancer and in human peripheral blood mononuclear cells. Mechanistic studies were carried out using toll-like receptor 4 (TLR4) knockout mice. Immune cells and cytokines in the serum, tumor and lymph nodes were analyzed by flow cytometry, PCR, ELISA and ELISPOT.

RESULTS

rBCG-S.FimH exhibited markedly improved adhesion and more rapid internalization into urothelial cells than wild-type BCG, resulting in more potent antitumor activity in orthotopic murine models of bladder cancer. To our surprise, rBCG-S.FimH elicited a much more prominent Th1-biased immune response known to be positively correlated with BCG efficacy. Mechanistic studies using TLR4 knockout mouse showed that rBCG-S.FimH could induce enhanced dendritic cell activation and tumor antigen-specific immune response in a TLR4-dependent manner. Furthermore, human peripheral blood mononuclear cells stimulated by rBCG-S.FimH also showed better tumoricidal effects than those using wild-type BCG.

CONCLUSION

rBCG-S.FimH is a novel BCG strain with significantly improved efficacy against bladder cancer. Since intravesical BCG immunotherapy is the first-line treatment for NMIBC, which accounts for more than 70% of all bladder cancer cases, our results provide a compelling rationale for clinical development.

Pharmacogenetic inhibition of lumbosacral sensory neurons alleviates visceral hypersensitivity in a mouse model of chronic pelvic pain

The study investigated the cellular and molecular mechanisms in the peripheral nervous system (PNS) underlying the symptoms of urologic chronic pelvic pain syndrome (UCPPS) in mice. This work also aimed to test the feasibility of reversing peripheral sensitization in vivo in alleviating UCPPS symptoms. Intravesical instillation of vascular endothelial growth factor A (VEGFA) was used to induce UCPPS-like symptoms in mice. Spontaneous voiding spot assays and manual Von Frey tests were used to evaluate the severity of lower urinary tract symptoms (LUTS) and visceral hypersensitivity in VEGFA-instilled mice. Bladder smooth muscle strip contractility recordings (BSMSC) were used to identify the potential changes in myogenic and neurogenic detrusor muscle contractility at the tissue-level. Quantitative real-time PCR (qPCR) and fluorescent immunohistochemistry were performed to compare the expression levels of VEGF receptors and nociceptors in lumbosacral dorsal root ganglia (DRG) between VEGFA-instilled mice and saline-instilled controls. To manipulate primary afferent activity, Gi-coupled Designer Receptors Exclusively Activated by Designer Drugs (Gi-DREADD) were expressed in lumbosacral DRG neurons of TRPV1-Cre-ZGreen mice via targeted adeno-associated viral vector (AAVs) injections. A small molecule agonist of Gi-DREADD, clozapine-N-oxide (CNO), was injected into the peritoneum (i. p.) in awake animals to silence TRPV1 expressing sensory neurons in vivo during physiological and behavioral recordings of bladder function. Intravesical instillation of VEGFA in the urinary bladders increased visceral mechanical sensitivity and enhanced RTX-sensitive detrusor contractility. Sex differences were identified in the baseline detrusor contractility responses and VEGF-induced visceral hypersensitivity. VEGFA instillations in the urinary bladder led to significant increases in the mRNA and protein expression of transient receptor potential cation channel subfamily A member 1 (TRPA1) in lumbosacral DRG, whereas the expression levels of transient receptor potential cation channel subfamily V member 1 (TRPV1) and VEGF receptors (VEGFR1 and VEGFR2) remained unchanged when compared to saline-instilled animals. Importantly, the VEGFA-induced visceral hypersensitivity was reversed by Gi-DREADD-mediated neuronal silencing in lumbosacral sensory neurons. Activation of bladder VEGF signaling causes sensory neural plasticity and visceral hypersensitivity in mice, confirming its role of an UCPPS biomarker as identified by the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) research studies. Pharmacogenetic inhibition of lumbosacral sensory neurons in vivo completely reversed VEGFA-induced pelvic hypersensitivity in mice, suggesting the strong therapeutic potential for decreasing primary afferent activity in the treatment of pain severity in UCPPS patients.

Urinary Incontinence and Alzheimer's Disease: Insights From Patients and Preclinical Models

Alzheimer's disease effects a large percentage of elderly dementia patients and is diagnosed on the basis of amyloid plaques and neurofibrillary tangles (NFTs) present in the brain. Urinary incontinence (UI) is often found in the elderly populations and multiple studies have shown that it is more common in Alzheimer's disease patients than those with normal cognitive function. However, the link between increased UI and Alzheimer's disease is still unclear. Amyloid plaques and NFTs present in micturition centers of the brain could cause a loss of signal to the bladder, resulting in the inability to properly void. Additionally, as Alzheimer's disease progresses, patients become less likely to recognize the need or understand the appropriate time and place to void. There are several treatments for UI targeting the muscarinic and β3 adrenergic receptors, which are present in the bladder and the brain. While these treatments may aid in UI, they often have effects on the brain with cognitive impairment side-effects. Acetylcholine esterase inhibitors are often used in treatment of Alzheimer's disease and directly oppose effects of anti-muscarinics used for UI, making UI management in Alzheimer's disease patients difficult. There are currently over 200 pre-clinical models of Alzheimer's disease, however, little research has been done on voiding disfunction in these models. There is preliminary data suggesting these models have similar voiding behavior to Alzheimer's disease patients but much more research is needed to understand the link between UI and Alzheimer's disease and discover better treatment options for managing both simultaneously.

Metformin abrogates the voiding dysfunction induced by prolonged methylglyoxal intake

Methylglyoxal (MGO) is a reactive carbonyl species found at high levels in blood of diabetic patients. The anti-hyperglycemic drug metformin can scavenger MGO and reduce the formation of advanced glycation end products (AGEs). Here, we aimed to investigate if MGO-induced bladder dysfunction can be reversed by metformin. Male C57/BL6 mice received 0.5% MGO in drinking water for 12 weeks, and metformin (300 mg/kg, daily gavage) was given in the last two weeks. The bladder functions were evaluated by performing voiding behavior assays, cystometry and in vitro bladder contractions. MGO intake markedly elevated the levels of MGO and fluorescent AGEs in serum and reduced the mRNA expression and activity of glyoxalase (Glo1) in bladder tissues. Glucose levels were unaffected among groups. MGO intake also increased the urothelium thickness and collagen content of the bladder. Void spot assays in conscious mice revealed an increased void volume in MGO group. The cystometric assays in anesthetized mice revealed increases of basal pressure, non-voiding contractions frequency, bladder capacity, inter-micturition pressure and residual volume, which were accompanied by reduced voiding efficiency in MGO group. In vitro bladder contractions to carbachol, α,β-methylene ATP and electrical-field stimulation were significantly greater in MGO group. Metformin normalized the changes of MGO and AGEs levels, Glo1 expression and activity, urothelium thickness and collagen content. The MGO-induced voiding dysfunction were all restored by metformin treatment. Our findings strongly suggest that the amelioration of MGO-induced voiding dysfunction by metformin relies on its ability to scavenger MGO, preventing its accumulation in blood.

Knockin mouse models demonstrate differential contributions of synaptotagmin-1 and -2 as receptors for botulinum neurotoxins

Botulinum neurotoxins (BoNTs) are the most potent toxins known and are also utilized to treat a wide range of disorders including muscle spasm, overactive bladder, and pain. BoNTs' ability to target neurons determines their specificity, potency, and therapeutic efficacy. Homologous synaptic vesicle membrane proteins synaptotagmin-1 (Syt1) and synaptotagmin-2 (Syt2) have been identified as receptors for BoNT family members including BoNT/B, DC, and G, but their contributions at physiologically relevant toxin concentrations in vivo have yet to be validated and established. Here we generated two knockin mutant mouse models containing three designed point-mutations that specifically disrupt BoNT binding in endogenous Syt1 or Syt2, respectively. Utilizing digit abduction score assay by injecting toxins into the leg muscle, we found that Syt1 mutant mice showed similar sensitivity as the wild type mice, whereas Syt2 mutant mice showed reduced sensitivity to BoNT/B, DC, and G, demonstrating that Syt2 is the dominant receptor at skeletal neuromuscular junctions. We further developed an in vivo bladder injection assay for analyzing BoNT action on bladder tissues and demonstrated that Syt1 is the dominant toxin receptor in autonomic nerves controlling bladder tissues. These findings establish the critical role of protein receptors for the potency and specificity of BoNTs in vivo and demonstrate the differential contributions of Syt1 and Syt2 in two sets of clinically relevant target tissues.

Functional roles for PIEZO1 and PIEZO2 in urothelial mechanotransduction and lower urinary tract interoception

The mechanisms that link visceral mechanosensation to the perception of internal organ status (i.e., interoception) remain elusive. In response to bladder filling, the urothelium releases ATP, which is hypothesized to stimulate voiding function by communicating the degree of bladder fullness to subjacent tissues, including afferent nerve fibers. To determine if PIEZO channels function as mechanosensors in these events, we generated conditional urothelial Piezo1-, Piezo2-, and dual Piezo1/2-knockout (KO) mice. While functional PIEZO1 channels were expressed in all urothelial cell layers, Piezo1-KO mice had a limited phenotype. Piezo2 expression was limited to a small subset of superficial umbrella cells, yet male Piezo2-KO mice exhibited incontinence (i.e., leakage) when their voiding behavior was monitored during their active dark phase. Dual Piezo1/2-KO mice had the most affected phenotype, characterized by decreased urothelial responses to mechanical stimulation, diminished ATP release, bladder hypoactivity in anesthetized Piezo1/2-KO females but not males, and urinary incontinence in both male and female Piezo1/2-KO mice during their dark phase but not inactive light one. Our studies reveal that the urothelium functions in a sex- and circadian rhythm–dependent manner to link urothelial PIEZO1/2 channel–driven mechanotransduction to normal voiding function and behavior, and in the absence of these signals, bladder dysfunction ensues.

A NEW approach for characterizing mouse urinary pathophysiologies

The void spot assay (VSA) is a cost-effective method for evaluating and quantifying mouse urinary voiding phenotypes. The VSA has been used to differentiate voiding behaviors between experimental groups, but not as a diagnostic assay. To build toward this goal, we used the VSA to define voiding patterns of male mice with diabetic diuresis (BTBR.Cg-Lepob /WiscJ mice), irritative urinary dysfunction (E. coli UTI89 urinary tract infection), and obstructive urinary dysfunction (testosterone and estradiol slow-release implants) compared to their respective controls. Many studies compare individual VSA endpoints (urine spot size, quantity, or distribution) between experimental groups. Here, we consider all endpoints collectively to establish VSA phenomes of mice with three different etiologies of voiding dysfunction. We created an approach called normalized endpoint work through (NEW) to normalize VSA outputs to control mice, and then applied principal components analysis and hierarchical clustering to 12 equally weighted, normalized, scaled, and zero-centered VSA outcomes collected from each mouse (the VSA phenome). This approach accurately classifies mice based on voiding dysfunction etiology. We used principal components analysis and hierarchical clustering to show that some aged mice (>24 m old) develop an obstructive or a diabetic diuresis VSA phenotype while others develop a unique phenotype that does not cluster with that of diabetic, infected, or obstructed mice. These findings support use of the VSA to identify specific urinary phenotypes in mice and the continued use of aged mice as they develop urinary dysfunction representative of the various etiologies of LUTS in men.

A mouse model of endometriosis that displays vaginal, colon, cutaneous, and bladder sensory comorbidities

Endometriosis is a painful inflammatory disorder affecting ~10% of women of reproductive age. Although chronic pelvic pain (CPP) remains the main symptom of endometriosis patients, adequate treatments for CPP are lacking. Animal models that recapitulate the features and symptoms experienced by women with endometriosis are essential for investigating the etiology of endometriosis, as well as developing new treatments. In this study, we used an autologous mouse model of endometriosis to examine a combination of disease features and symptoms including: a 10 week time course of endometriotic lesion development; the chronic inflammatory environment and development of neuroangiogenesis within lesions; sensory hypersensitivity and altered pain responses to vaginal, colon, bladder, and skin stimulation in conscious animals; and spontaneous animal behavior. We found significant increases in lesion size from week 6 posttransplant. Lesions displayed endometrial glands, stroma, and underwent neuroangiogenesis. Additionally, peritoneal fluid of mice with endometriosis contained known inflammatory mediators and angiogenic factors. Compared to Sham, mice with endometriosis displayed: enhanced sensitivity to pain evoked by (i) vaginal and (ii) colorectal distension, (iii) altered bladder function and increased sensitivity to cutaneous (iv) thermal and (v) mechanical stimuli. The development of endometriosis had no effect on spontaneous behavior. This study describes a comprehensive characterization of a mouse model of endometriosis, recapitulating the clinical features and symptoms experienced by women with endometriosis. Moreover, it delivers the groundwork to investigate the etiology of endometriosis and provides a platform for the development of therapeutical interventions to manage endometriosis-associated CPP.

The influence of intermittent hypoxia, obesity, and diabetes on male genitourinary anatomy and voiding physiology

We used male BTBR mice carrying the Lep^ob mutation, which are subject to severe and progressive obesity and diabetes beginning at 6 wk of age, to examine the influence of one specific manifestation of sleep apnea, intermittent hypoxia (IH), on male urinary voiding physiology and genitourinary anatomy. A custom device was used to deliver continuous normoxia (control) or IH to wild-type and Lep^ob/ob (mutant) mice for 2 wk. IH was delivered during the 12-h inactive (light) period in the form of 90 s of 6% O₂ followed by 90 s of room air. Continuous room air was delivered during the 12-h active (dark) period. We then evaluated genitourinary anatomy and physiology. As expected for the type 2 diabetes phenotype, mutant mice consumed more food and water, weighed more, and voided more frequently and in larger urine volumes. They also had larger bladder volumes but smaller prostates, seminal vesicles, and urethras than wild-type mice. IH decreased food consumption and increased bladder relative weight independent of genotype and increased urine glucose concentration in mutant mice. When evaluated based on genotype (normoxia + IH), the incidence of pathogenic bacteriuria was greater in mutant mice than in wild-type mice, and among mice exposed to IH, bacteriuria incidence was greater in mutant mice than in wild-type mice. We conclude that IH exposure and type 2 diabetes can act independently and together to modify male mouse urinary function. NEW & NOTEWORTHY Metabolic syndrome and obstructive sleep apnea are common in aging men, and both have been linked to urinary voiding dysfunction. Here, we show that metabolic syndrome and intermittent hypoxia (a manifestation of sleep apnea) have individual and combined influences on voiding function and urogenital anatomy in male mice.

Therapeutic effect of modulating the NLRP3-regulated transforming growth factor-β signaling pathway on interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a disorder with complex pathogenesis and lacks effective treatment. Chronic inflammation is the main pathogenesis of Hunner-type IC/BPS. The NLR family pyrin domain-containing 3 (NLRP3) inflammasome-related transforming growth factor-β (TGF-β)/Smad signaling pathway plays a crucial role in inflammation-related tissue fibrosis. Lipopolysaccharide (LPS) and protamine sulfate (LPS/PS) were instilled into the mouse bladder twice a week for 5 consecutive weeks to establish a chronic inflammation-induced IC/BPS model (LPS/PS model). Following LPS/PS treatment, curcumin (oral, 100 mg/kg; a potent NLRP3 modulator) was administered for 2 weeks in the curcumin treatment group, and normal saline was used for the sham group. Bladder function was evaluated by performing the voiding spot assay and examining the status of urothelial denudation and fibrosis in bladder tissues. The expression of NLRP3 inflammasome, interleukin-1β, TGF-β, Smad, vimentin, and E-cadherin in bladder tissues was evaluated through immunohistochemistry staining. Results revealed that the repeated instillation of LPS/PS leads to voiding dysfunction, bladder urothelium denudation, and detrusor muscle fibrosis through the upregulation of the NLRP3 inflammasome/IL-1β-related TGF-β/Smad pathway and the increased epithelial-mesenchymal transition process in bladder tissues. The downregulation of the NLRP3 inflammasome/IL-1β-related TGF-β/Smad pathway in bladder tissues through curcumin effectively mitigated bladder injury in the LPS/PS model. In conclusion, the NLRP3 inflammasome/IL-1β-related TGF-β/Smad pathway plays a crucial role in bladder injury in the LPS/PS model, and modulation of this pathway, such as by using curcumin, can effectively mitigate the sequelae of chronic inflammation-induced IC/BPS.

Neurophysiological control of urinary bladder storage and voiding-functional changes through development and pathology

The effective storage of urine and its expulsion relies upon the coordinated activity of parasympathetic, sympathetic, and somatic innervations to the lower urinary tract (LUT). At birth, all mammalian neonates lack the ability to voluntary regulate bladder storage or voiding. The ability to control urinary bladder activity is established as connections to the central nervous system (CNS) form through development. The neural regulation of the LUT has been predominantly investigated in adult animal models where comparatively less is known about the neonatal and postnatal neurophysiological development that facilitate urinary continence. Furthermore, congenital neurological or anatomical defects can adversely affect both storage and voiding functions through postnatal development and into adulthood, leading to secondary conditions including vesicoureteral reflux, chronic urinary tract infections, and end-stage renal disease. Therefore, the aim of the review is to provide the current knowledge available on neurophysiological regulation of the LUT through pre- to postnatal development of human and animal models and the consequences of congenital anomalies that can affect LUT neural function.

Genetic background but not prostatic epithelial beta-catenin influences susceptibility of male mice to testosterone and estradiol-induced urinary dysfunction

Urinary voiding dysfunction in aging men can cause bothersome symptoms and irreparable tissue damage. Underlying mechanisms are not fully known. We previously demonstrated that subcutaneous, slow-release testosterone and estradiol implants (T+E2) drive a pattern of urinary voiding dysfunction in male mice that resembles that of aging men. The initial goal of this study was to test the hypothesis that prostatic epithelial beta-catenin (Ctnnb1) is required for T+E2-mediated voiding dysfunction. Targeted Ctnnb1 deletion did not significantly change voiding function in control or T+E2 treated mice but led to the surprising discovery that the C57BL/6J × FVB/NJ × 129S1 mixed genetic background onto which Ctnnb1 loss of function alleles were maintained is profoundly susceptible to voiding dysfunction. The mixed background mice develop a more rapid T+E2-mediated increase in spontaneous urine spotting, are more impaired in ability to initiate bladder contraction, and develop larger and heavier bladders than T+E2 treated C57BL/6J pure bred mice. To better understand mechanisms, we separately evaluated contributions of T and E2 and found that E2 mediates voiding dysfunction. Our findings that genetic factors serve as modifiers of responsiveness to T and E2 demonstrate the need to control for genetic background in studies of male voiding dysfunction. We also show that genetic factors could control severity of voiding dysfunction. We demonstrate the importance of E2 as a key mediator of voiding impairment, and show that the concentration of E2 in subcutaneous implants determines the severity of voiding dysfunction in mice, demonstrating that the mouse model is tunable, a factor which is important for future pharmacological intervention studies.

Functional constipation induces bladder overactivity associated with upregulations of Htr2 and Trpv2 pathways

Bladder and bowel dysfunction (BBD) is a common yet underdiagnosed paediatric entity that describes lower urinary tract symptoms (LUTS) accompanied by abnormal bowel patterns manifested as constipation and/or encopresis. LUTS usually manifest as urgency, urinary frequency, incontinence, and urinary tract infections (UTI). Despite increasing recognition of BBD as a risk factor for long-term urinary tract problems including recurrent UTI, vesicoureteral reflux, and renal scarring, the mechanisms underlying BBD have been unclear, and treatment remains empirical. We investigated how constipation affects the lower urinary tract function using a juvenile murine model of functional constipation. Following four days of functional constipation, animals developed LUTS including urinary frequency and detrusor overactivity evaluated by awake cystometry. Physiological examination of detrusor function in vitro using isolated bladder strips, demonstrated a significant increase in spontaneous contractions without affecting contractile force in response to electrical field stimulation, carbachol, and KCl. A significant upregulation of serotonin receptors, Htr2a and Htr2c, was observed in the bladders from mice with constipation, paralleled with augmented spontaneous contractions after pre-incubation of the bladder strips with 0.5 µM of serotonin. These results suggest that constipation induced detrusor overactivity and increased excitatory serotonin receptor activation in the urinary bladder, which contributes to the development of BBD.

A uropathogenic E. coli UTI89 model of prostatic inflammation and collagen accumulation for use in studying aberrant collagen production in the prostate

Bacterial infection is one known etiology of prostatic inflammation. Prostatic inflammation is associated with prostatic collagen accumulation and both are linked to progressive lower urinary tract symptoms in men. We characterized a model of prostatic inflammation using transurethral instillations of Escherichia coli UTI89 in C57BL/6J male mice with the goal of determining the optimal instillation conditions, understanding the impact of instillation conditions on urinary physiology, and identifying ideal prostatic lobes and collagen 1a1 prostatic cell types for further analysis. The smallest instillation volume tested (50 µL) distributed exclusively to the bladder, 100- and 200-µL volumes distributed to the bladder and prostate, and a 500-µL volume distributed to the bladder, prostate, and ureter. A threshold optical density of 0.4 E. coli UTI89 in the instillation fluid was necessary for significant (P < 0.05) prostate colonization. E. coli UTI89 infection resulted in a low frequency, high volume spontaneous voiding pattern. This phenotype was due to exposure to E. coli UTI89, not catheterization alone, and was minimally altered by a 50-µL increase in instillation volume and doubling of E. coli concentration. Prostate inflammation was isolated to the dorsal prostate and was accompanied by increased collagen density. This was partnered with increased density of protein tyrosine phosphatase receptor type C+, procollagen type I-α1+ copositive cells and decreased density of α2-smooth muscle actin+, procollagen type I-α1+ copositive cells. Overall, we determined that this model is effective in altering urinary phenotype and producing prostatic inflammation and collagen accumulation in mice.

Probabilistic, spinally-gated control of bladder pressure and autonomous micturition by Barrington's nucleus CRH neurons

Micturition requires precise control of bladder and urethral sphincter via parasympathetic, sympathetic and somatic motoneurons. This involves a spino-bulbospinal control circuit incorporating Barrington’s nucleus in the pons (Barr). Ponto-spinal glutamatergic neurons that express corticotrophin-releasing hormone (CRH) form one of the largest Barr cell populations. Barr^CRH neurons can generate bladder contractions, but it is unknown whether they act as a simple switch or provide a high-fidelity pre-parasympathetic motor drive and whether their activation can actually trigger voids. Combined opto- and chemo-genetic manipulations along with multisite extracellular recordings in urethane anaesthetised CRH^Cre mice show that Barr^CRH neurons provide a probabilistic drive that generates co-ordinated voids or non-voiding contractions depending on the phase of the micturition cycle. CRH itself provides negative feedback regulation of this process. These findings inform a new inferential model of autonomous micturition and emphasise the importance of the state of the spinal gating circuit in the generation of voiding.

Radiation cystitis modeling: A comparative study of bladder fibrosis radio-sensitivity in C57BL/6, C3H, and BALB/c mice

A subset of patients receiving radiation therapy for pelvic cancer develop radiation cystitis, a complication characterized by mucosal cell death, inflammation, hematuria, and bladder fibrosis. Radiation cystitis can reduce bladder capacity, cause incontinence, and impair voiding function so severely that patients require surgical intervention. Factors influencing onset and severity of radiation cystitis are not fully known. We tested the hypothesis that genetic background is a contributing factor. We irradiated bladders of female C57BL/6, C3H, and BALB/c mice and evaluated urinary voiding function, bladder shape, histology, collagen composition, and distribution of collagen-producing cells. We found that the genetic background profoundly affects the severity of radiation-induced bladder fibrosis and urinary voiding dysfunction. C57BL/6 mice are most susceptible and C3H mice are most resistant. Irradiated C57BL/6 mouse bladders are misshapen and express more abundant collagen I and III proteins than irradiated C3H and BALB/c bladders. We localized Col1a1 and Col3a1 mRNAs to FSP1-negative stromal cells in the bladder lamina propria and detrusor. The number of collagen I and collagen III-producing cells can predict the average voided volume of a mouse. Collectively, we show that genetic factors confer sensitivity to radiation cystitis, establish C57BL/6 mice as a sensitive preclinical model, and identify a potential role for FSP1-negative stromal cells in radiation-induced bladder fibrosis.

Methods for Assessing Lower Urinary Tract Function in Animal Models

Lower urinary tract dysfunction affects a multitude of patients. Current therapeutic approaches are limited and very little is known about the mechanisms in failure of bladder control. Thus, more basic research is clearly needed to elucidate the underlying pathological mechanisms and to develop novel treatment strategies in urology. Noninvasive tests such as the void-spot assay and the metabolic cage and more invasive urodynamics investigations are currently used to assess lower urinary tract function in animals, in particular rodents. The noninvasive tests give some insights into the functionality of the system, whereas urodynamics testing yields an objective evaluation that allows distinction of different pathologies and investigations of the underlying neuronal malfunctions. PATIENT SUMMARY: We briefly summarize methods currently used to assess impairments of bladder function in animal models. Both noninvasive and invasive methods are available and can be used to understand and improve human health. An accurate and detailed diagnosis is, however, possible only with urodynamics assessments.

Urological complications of obesity and diabetes in males and females of three mouse models: temporal manifestations

Diabetic bladder dysfunction is a frequent complication of diabetes. Although many mouse models of diabetes now exist, there has been little systematic effort to characterize them for the timing of onset and severity of bladder dysfunction. We monitored metabolic status and tested bladder function by void spot assay and limited anesthetized cystometry in both male and female mice of three models of obesity and diabetes: a type 1 diabetes model (the Akita mouse) and two type 2 diabetes models [the diet-induced obese (DIO) model and the ob/ob mouse]. Akita mice had insulin pellets implanted subcutaneously every 3 mo to mimic poorly controlled type 1 diabetes in humans. Mice were hyperglycemic by 48 days after implants. Female mice exhibited no bladder dysfunction at any age up to 20 mo and gained weight normally. In contrast, by 7 mo, male Akita mice developed a profound polyuria and failed to show normal weight gain. There were no observable signs of bladder dysfunction in either sex. DIO mice on high/low-fat diets for 16 mo exhibited mild hyperglycemia in female mice (not in male mice), mild weight gain, and no evidence of bladder dysfunction. Ob/ob mice were followed for 8 mo and became extremely obese. Male and female mice were glucose intolerant, insulin intolerant, and hyperinsulinemic at 4 mo. By 8 mo, their metabolic status had improved but was still abnormal. Urine volume increased in male mice but not in female mice. Bladder dysfunction was observed in the spotting patterns of female mice at 4 and 6 mo of age, resolving by 8 mo. We conclude there are dramatic sex-related differences in lower urinary tract function in these models. Male Akita mice may be a good model for polyuria-related bladder remodeling, whereas female ob/ob mice may better mimic storage problems related to loss of outlet control in a setting of type 2 diabetes complicated by obesity.

Micturition video thermography in awake, behaving mice

BACKGROUND

Our understanding of the neural circuits controlling micturition and continence is constrained by a paucity of techniques for measuring voiding in awake, behaving mice.

NEW METHOD

To facilitate progress in this area, we developed a new, non-invasive assay, micturition video thermography (MVT), using a down-facing thermal camera above mice on a filter paper floor.

RESULTS

Most C57B6/J mice void infrequently, with a stereotyped behavioral sequence, and usually in a corner. The timing of each void is indicated by the warm thermal contrast of freshly voided urine. Over the following 10-15 min, urine cools to ∼3 °C below the ambient temperature and spreads radially in the filter paper. By measuring the area of cool contrast comprising this "thermal void spot," we can derive the initially voided volume. Thermal videos also reveal mouse behaviors including a home-corner preference apart from void spots, and a stereotyped, seconds-long pause while voiding.

COMPARISON WITH EXISTING METHODS AND CONCLUSIONS

MVT is a robust, non-invasive method for measuring the timing, volume, and location of voiding. It improves on an existing technique, the void spot assay, by adding timing information, and unlike the cystometrogram preparation, MVT does not require surgical catheterization. Combining MVT with current neuroscience techniques will improve our understanding of the neural circuits that control continence, which is important for addressing the growing number of patients with urinary incontinence as the population ages.

Dysregulated NO/PDE5 signaling in the sickle cell mouse lower urinary tract: Reversal by oral nitrate therapy

AIMS

Nitric oxide (NO) has a critical, but not well understood, influence in the physiology of the lower urinary tract. We evaluated the effect of NO/phosphodiesterase (PDE)5 signaling in voiding dysfunction in the sickle cell disease (SCD) mouse, characterized by low NO bioavailability.

MAIN METHODS

Adult SCD (Sickle) and wild-type (WT) male mice were treated daily with sodium nitrate (10 mM) or vehicle. After 18 days, blood was obtained for nitrite measurement, urethra was collected for organ bath study, and bladder and urethra were collected for Western blot analysis of PDE5 phosphorylation (Ser-92) (activated form). Non-anesthetized mice underwent evaluation of urine volume by void spot assay. eNOS phosphorylation (Ser-1177) and nNOS phosphorylation (Ser-1412) (positive regulatory sites) were evaluated in the bladder and urethra of untreated mice.

KEY FINDINGS

Sickle mice exhibited decreased eNOS, nNOS, and PDE5 phosphorylation in the bladder and urethra, decreased plasma nitrite levels, increased relaxation of phenylephrine-contracted urethral tissue to an NO donor sodium nitroprusside, and increased total urine volume, compared with WT mice. Nitrate treatment normalized plasma nitrite levels, relaxation of urethra to sodium nitroprusside, PDE5 phosphorylation in the urethra and bladder, and urine volume in Sickle mice.

SIGNIFICANCE

Derangement in PDE5 activity associated with basally low NO bioavailability in the bladder and urethra contributes to the molecular basis for voiding abnormalities in Sickle mice. Inorganic nitrate supplementation normalized voiding in Sickle mice through mechanisms likely involving upregulation of PDE5 activity. These findings suggest that interventions targeting dysregulatory NO/PDE5 signaling may ameliorate overactive bladder in SCD.

Insight and Resources From a Study of the "Impact of Sex, Androgens, and Prostate Size on C57BL/6J Mouse Urinary Physiology

The purpose of this symposium report is to summarize information from a session 3 oral presentation at the Society of Toxicologic Pathology Annual Symposium in Raleigh, North Carolina. Mice are genetically tractable and are likely to play an important role in elucidating environmental, genetic, and aging-related mechanisms of urinary dysfunction in men. We and others have made significant strides in developing quantitative methods for assessing mouse urinary function and our collaborators recently showed that aging male mice, like men, develop urinary dysfunction. Yet, it remains unclear how mouse prostate anatomy and histology relate to urinary function. The purpose of this report is to share foundational resources for evaluating mouse prostate histology and urinary physiology from our recent publication "Impact of Sex, Androgens, and Prostate Size on C57BL/6J Mouse Urinary Physiology: Functional Assessment." We will begin with a review of prostatic embryology in men and mice, then move to comparative histology resources, and conclude with quantitative measures of rodent urinary physiology.

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.

Urinary dysfunction in transgenic sickle cell mice: model of idiopathic overactive bladder syndrome

Voiding abnormalities are common among the sickle cell disease (SCD) population, among which overactive bladder (OAB) syndrome is observed at rates as high as 39%. Although detrusor overactivity is the most common cause of OAB, its molecular pathophysiology is not well elucidated. The nitric oxide (NO) signaling pathway has been implicated in the regulation of lower genitourinary tract function. In the present study, we evaluated the role of the NO signaling pathway in voiding function of transgenic SCD mice compared with combined endothelial and neuronal NO synthase gene-deficient mice, both serving as models of NO deficiency. Mice underwent void spot assay and cystometry, and bladder and urethral specimens were studied using in vitro tissue myography. Both mouse models exhibited increased void volumes; increased nonvoiding and voiding contraction frequencies; decreased bladder compliance; increased detrusor smooth muscle contraction responses to electrical field stimulation, KCl, and carbachol; and increased urethral smooth muscle relaxation responses to sodium nitroprusside compared with WT mice. In conclusion, our comprehensive behavioral and functional study of the SCD mouse lower genitourinary tract, in correlation with that of the NO-deficient mouse, reveals NO effector actions in voiding function and suggests that NO signaling derangements are associated with an OAB phenotype. These findings may allow further study of molecular targets for the characterization and evaluation of OAB.