Neurotrophins as regulators of urinary bladder function

Skin-inspired, sensory robots for electronic implants

Drawing inspiration from cohesive integration of skeletal muscles and sensory skins in vertebrate animals, we present a design strategy of soft robots, primarily consisting of an electronic skin (e-skin) and an artificial muscle. These robots integrate multifunctional sensing and on-demand actuation into a biocompatible platform using an in-situ solution-based method. They feature biomimetic designs that enable adaptive motions and stress-free contact with tissues, supported by a battery-free wireless module for untethered operation. Demonstrations range from a robotic cuff for detecting blood pressure, to a robotic gripper for tracking bladder volume, an ingestible robot for pH sensing and on-site drug delivery, and a robotic patch for quantifying cardiac function and delivering electrotherapy, highlighting the application versatilities and potentials of the bio-inspired soft robots. Our designs establish a universal strategy with a broad range of sensing and responsive materials, to form integrated soft robots for medical technology and beyond.

Nerve Growth Factor and Brain-Derived Neurotrophic Factor as Potential Biomarkers of Mirabegron Efficacy in Patients with Overactive Bladder Syndrome

INTRODUCTION

Overactive Bladder Syndrome (OAB) significantly impacts quality of life, necessitating improved diagnostic tools and treatment monitoring. This study explores the potential of neurotrophins, nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) as urinary biomarkers in patients with OAB undergoing mirabegron therapy, a β3-adrenergic agonist. This investigation is aimed at providing insights into the potential of neurotrophins to enhance OAB diagnosis and assess treatment efficacy.

MATERIALS AND METHODS

Urinary NGF and BDNF levels were measured in 15 healthy controls and 30 patients with OAB. Patients were treated with mirabegron 50 mg once daily. Urinary NGF and BDNF levels were measured by enzyme-linked immunosorbent assay method and normalized by urinary creatinine levels (NGF/Cre and BDNF/Cre). The urinary NGF/Cre and BDNF/Cre levels were compared between controls and patients with OAB and subsequently at baseline and 3 months after mirabegron treatment. Treatment efficacy was assessed with the Indevus Urgency Severity Scale (IUSS) questionnaire.

RESULTS

Urinary NGF/Cre and BDNF/Cre levels were significantly higher in patients with OAB than in the controls (p < 0.001 and p = 0.03 respectively). Moreover, NGF/Cre and BDNF/Cre levels significantly decreased post-mirabegron treatment (p < 0.001 and p = 0.005 respectively). Patients with improvement of OAB symptoms after treatment showed lower levels of NGF/Cre at the 3-month evaluation than those with no improvement (p = 0.05).

CONCLUSION

Although both NGF/Cre and BDNF/Cre levels were significantly decreased after mirabegron treatment, only NGF/Cre levels were associated with treatment response.

Quantification of Aging-Related Decreases in Sensory Innervation of the Bladder Trigone in Rats

PURPOSE

The prevalence of lower urinary tract symptoms (LUTS), characterized by problems regarding storage and/or voiding of urine, is known to significantly increase with age. Effective communication between the lower urinary tract and the central nervous system (CNS) is essential for the optimal function of this system, and heavily relies on the efficient interaction between the bladder urothelium and the afferent nerve fibers situated in close proximity to the urothelium within the lamina propria.

METHODS

We aimed to quantify aging-related differences in the expression of calcitonin gene-related peptide (CGRP, an established marker for sensory nerve fibers) in the trigonal mucosal layers of young (3-4 months) and aged (25-30 months) rats. We evaluated trigonal tissue from 3 animals per age group. Tissue was serially sectioned at 10 μm and stained for CGRP. Images were taken along the full length of the tissue. For each image we computed the total CGRP-positive area (μm2) and the median value for each animal was used for further analysis.

RESULTS

Upon statistical analysis the aged rats show a significantly lower CGRP-positive area compared to young rats (P=0.0049). These results indicate that aging has a negative effect on the area of CGRP-positive signal in the trigone.

CONCLUSION

The structural and functional integrity of the sensory web in the trigonum of rats is negatively affected by the aging process, potentially leading to impaired communication between the bladder urothelium the CNS. Consequently, these perturbations in the sensory system may contribute to the pathogenesis or exacerbation LUTS.

Synthesis and secretion of Nerve Growth Factor is regulated by Nitric Oxide in bladder cells in vitro under a hyperglycemic environment

Urine samples of female patients with overactive bladder (OAB) are characterized by low levels of nerve growth factor (NGF) and elevated concentrations of nitric oxide (NO) compared to healthy controls. We therefore examined how NO might regulate NGF synthesis using rat bladder smooth muscle (SMCs) and urothelial (UROs) cells in culture. In UROs, incubation in hyperglycemic conditions to mimic insulin insensitivity present in the OAB cohort increased secretion of NO and concomitantly decreased NGF, except when the NO synthase inhibitor, l-NAME (1 mM) was present. Sodium nitroprusside (SNP) (300 μM, 24 h), a NO generator, decreased NGF levels and decreased cyclic GMP (cGMP) content, a process validated by the cGMP synthase inhibitor ODQ (100 μM). Alternatively, SNP increased mRNA of both NGF and matrix metalloproteinase-9 (MMP-9). MMP-9 knockout of UROs by Crispr-Cas9 potently decreased the effect of SNP on NGF, implying a dependent role of NO on MMP-9. On the other hand, matrix metalloproteinase-7 (MMP-7) activity was increased by SNP, which taken together with increase in NGF mRNA, suggests a compensatory mechanism. In SMCs, hyperglycemic conditions had the same effect on extracellular content of NO and NGF than in UROs. SNP also decreased NGF secretion but increased cGMP content. Stable permeable analogs of cGMP 8-(4-Chlorophenylthio)-cGMP (1 mM) and N2,2'-O-Dibutyryl-cGMP (3 mM) inhibited NGF release. NGF and MMP-9 mRNA expression was unchanged by SNP. Deletion of MMP-9 in SMCs by Crispr-Cas9 did not alter the effect of SNP. Finally, SNP decreased MMP-7 activity, diminishing the conversion of proNGF to NGF. These results demonstrate that enhanced NO secretion triggered by high glucose decreases NGF secretion through pathways unique for each cell type that involve cGMP and proteases MMP-7 and MMP-9. These results might help to explain our observations from the urine from patients with OAB associated with metabolic syndrome.

Neuro-Urology and Biobanking: An Integrated Approach for Advancing Research and Improving Patient Care

Understanding the molecular mechanisms underlying neuro-urological disorders is crucial for the development of targeted therapeutic interventions. Through the establishment of comprehensive biobanks, researchers can collect and store various biological specimens, including urine, blood, tissue, and DNA samples, to study these mechanisms. In the context of neuro-urology, biobanking facilitates the identification of genetic variations, epigenetic modifications, and gene expression patterns associated with neurogenic lower urinary tract dysfunction. These conditions often present as symptoms of neurological diseases such as Alzheimer's disease, multiple sclerosis, Parkinson's disease, spinal cord injury, and many others. Biobanking of tissue specimens from such patients is essential to understand why these diseases cause the respective symptoms and what can be done to alleviate them. The utilization of high-throughput technologies, such as next-generation sequencing and gene expression profiling, enables researchers to explore the molecular landscape of these conditions in an unprecedented manner. The development of specific and reliable biomarkers resulting from these efforts may help in early detection, accurate diagnosis, and effective monitoring of neuro-urological conditions, leading to improved patient care and management. Furthermore, these biomarkers could potentially facilitate the monitoring of novel therapies currently under investigation in neuro-urological clinical trials. This comprehensive review explores the synergistic integration of neuro-urology and biobanking, with particular emphasis on the translation of biobanking approaches in molecular research in neuro-urology. We discuss the advantages of biobanking in neuro-urological studies, the types of specimens collected and their applications in translational research. Furthermore, we highlight the importance of standardization and quality assurance when collecting samples and discuss challenges that may compromise sample quality and impose limitations on their subsequent utilization. Finally, we give recommendations for sampling in multicenter studies, examine sustainability issues associated with biobanking, and provide future directions for this dynamic field.

Brain-derived neurotrophic factor: Its role in energy balance and cancer cachexia

Brain-derived neurotrophic factor (BDNF) plays an important role in the development of the central and peripheral nervous system during embryogenesis. In the mature central nervous system, BDNF is required for the maintenance and enhancement of synaptic transmissions and the survival of neurons. Particularly, it is involved in the modulation of neurocircuits that control energy balance through food intake, energy expenditure, and locomotion. Regulation of BDNF in the central nervous system is complex and environmental factors affect its expression in murine models which may reflect to phenotype dramatically. Furthermore, BDNF and its high-affinity receptor tropomyosin receptor kinase B (TrkB), as well as pan-neurotrophin receptor (p75NTR) is expressed in peripheral tissues in adulthood and their signaling is associated with regulation of energy balance. BDNF/TrkB signaling is exploited by cancer cells as well and BDNF expression is increased in tumors. Intriguingly, previously demonstrated roles of BDNF in regulation of food intake, adipose tissue and muscle overlap with derangements observed in cancer cachexia. However, data about the involvement of BDNF in cachectic cancer patients and murine models are scarce and inconclusive. In the future, knock-in and/or knock-out experiments with murine cancer models could be helpful to explore potential new roles for BDNF in the development of cancer cachexia.

Molecular Mechanisms of Neurogenic Lower Urinary Tract Dysfunction after Spinal Cord Injury

This article provides a synopsis of current progress made in fundamental studies of lower urinary tract dysfunction (LUTD) after spinal cord injury (SCI) above the sacral level. Animal models of SCI allowed us to examine the effects of SCI on the micturition control and the underlying neurophysiological processes of SCI-induced LUTD. Urine storage and elimination are the two primary functions of the LUT, which are governed by complicated regulatory mechanisms in the central and peripheral nervous systems. These neural systems control the action of two functional units in the LUT: the urinary bladder and an outlet consisting of the bladder neck, urethral sphincters, and pelvic-floor striated muscles. During the storage phase, the outlet is closed, and the bladder is inactive to maintain a low intravenous pressure and continence. In contrast, during the voiding phase, the outlet relaxes, and the bladder contracts to facilitate adequate urine flow and bladder emptying. SCI disrupts the normal reflex circuits that regulate co-ordinated bladder and urethral sphincter function, leading to involuntary and inefficient voiding. Following SCI, a spinal micturition reflex pathway develops to induce an overactive bladder condition following the initial areflexic phase. In addition, without proper bladder-urethral-sphincter coordination after SCI, the bladder is not emptied as effectively as in the normal condition. Previous studies using animal models of SCI have shown that hyperexcitability of C-fiber bladder afferent pathways is a fundamental pathophysiological mechanism, inducing neurogenic LUTD, especially detrusor overactivity during the storage phase. SCI also induces neurogenic LUTD during the voiding phase, known as detrusor sphincter dyssynergia, likely due to hyperexcitability of Aδ-fiber bladder afferent pathways rather than C-fiber afferents. The molecular mechanisms underlying SCI-induced LUTD are multifactorial; previous studies have identified significant changes in the expression of various molecules in the peripheral organs and afferent nerves projecting to the spinal cord, including growth factors, ion channels, receptors and neurotransmitters. These findings in animal models of SCI and neurogenic LUTD should increase our understanding of pathophysiological mechanisms of LUTD after SCI for the future development of novel therapies for SCI patients with LUTD.

Urinary Oxidative Stress Biomarker Levels Might Be Useful in Identifying Functional Bladder Disorders in Women with Frequency and Urgency Syndrome

Purpose: lower urinary tract dysfunctions (LUTDs) are difficult to diagnose based on symptoms. This study used a cluster of urinary biomarkers, including inflammatory cytokines, neurogenic proteins, and oxidative stress biomarkers, to identify LUTDs in women with frequency and urgency symptoms. Methods: in total, 253 women with video urodynamics (VUDS)- and cystoscopy-confirmed detrusor overactivity (DO), interstitial cystitis/bladder pain syndrome (IC/BPS), dysfunctional voiding (DV), and hypersensitive bladder (HSB), and normal controls were included. Before diagnosis and treatment, urine samples were collected for analysis of biomarkers. The urine levels of biomarkers were compared between groups with bladder dysfunctions and controls and were combined to test the sensitivity in identifying total pathological bladder diseases and specific bladder diseases. Results: After video urodynamic study, VUDS, and urological examinations, bladder dysfunctions were classified into DO (n = 31), IC/BPS (n = 114), DV (n = 45), HSB (n = 29), and control (n = 34) groups. By using a cystomeric bladder capacity of ≤350 mL, 186/219 (84.9%) of the patients with DO, IC/BPS, DV, and HSB can be discriminated from the controls. Among these urine biomarkers, oxidative stress biomarkers 8-isoprostane, 8-hydroxydeoxyguanosine (8-OHdG), or total antioxidant capacity (TAC) are useful for identifying pathological bladder dysfunction (DO, IC/BPS, and DV) and HSB. With elevated IL-1β and lower IL-2, and elevated TNF-α levels, most patients with DV can be identified. Between DO and IC/BPS, a higher NGF level can identify 58.3% of IC/BPS cases, whereas a lower NGF level can identify 75.0% of DO cases. Conclusion: by using a cluster of urine biomarkers, DO, IC/BPS, and DV cases can be identified based on elevated levels of urine oxidative stress biomarkers 8-isoprostane, TAC, or 8-OHdG, and HSB cases with a low TAC. These urine biomarkers are useful for identifying specific LUTDs in women with frequency and urgency symptoms.

Molecular Mechanism Operating in Animal Models of Neurogenic Detrusor Overactivity: A Systematic Review Focusing on Bladder Dysfunction of Neurogenic Origin

Neurogenic detrusor overactivity (NDO) is a severe lower urinary tract disorder, characterized by urinary urgency, retention, and incontinence, as a result of a neurologic lesion that results in damage in neuronal pathways controlling micturition. The purpose of this review is to provide a comprehensive framework of the currently used animal models for the investigation of this disorder, focusing on the molecular mechanisms of NDO. An electronic search was performed with PubMed and Scopus for literature describing animal models of NDO used in the last 10 years. The search retrieved 648 articles, of which reviews and non-original articles were excluded. After careful selection, 51 studies were included for analysis. Spinal cord injury (SCI) was the most frequently used model to study NDO, followed by animal models of neurodegenerative disorders, meningomyelocele, and stroke. Rats were the most commonly used animal, particularly females. Most studies evaluated bladder function through urodynamic methods, with awake cystometry being particularly preferred. Several molecular mechanisms have been identified, including changes in inflammatory processes, regulation of cell survival, and neuronal receptors. In the NDO bladder, inflammatory markers, apoptosis-related factors, and ischemia- and fibrosis-related molecules were found to be upregulated. Purinergic, cholinergic, and adrenergic receptors were downregulated, as most neuronal markers. In neuronal tissue, neurotrophic factors, apoptosis-related factors, and ischemia-associated molecules are increased, as well as markers of microglial and astrocytes at lesion sites. Animal models of NDO have been crucial for understanding the pathophysiology of lower urinary tract (LUT) dysfunction. Despite the heterogeneity of animal models for NDO onset, most studies rely on traumatic SCI models rather than other NDO-driven pathologies, which may result in some issues when translating pre-clinical observations to clinical settings other than SCI.

Effects of pharmacological neurotrophin receptor inhibition on bladder function in female mice with cyclophosphamide-induced cystitis

Interstitial cystitis/bladder pain syndrome is a chronic inflammatory pelvic pain syndrome of unknown etiology characterized by a number of lower urinary tract symptoms, including increased urinary urgency and frequency, bladder discomfort, decreased bladder capacity, and pelvic pain. While its etiology remains unknown, a large body of evidence suggests a role for changes in neurotrophin signaling, particularly that of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). Here, we evaluated the effects of pharmacological inhibition of the NGF receptor TrkA, BDNF receptor TrkB, and pan-neurotrophin receptor p75NTR on bladder function in acute (4-hour) and chronic (8-day) mouse models of cyclophosphamide (CYP)-induced cystitis. TrkA inhibition via ARRY-954 significantly increased intermicturition interval and bladder capacity in control and acute and chronic CYP-treatment conditions. TrkB inhibition via ANA-12 significantly increased intermicturition interval and bladder capacity in acute, but not chronic, CYP-treatment conditions. Interestingly, intermicturition interval and bladder capacity significantly increased following p75NTR inhibition via LM11A-31 in the acute CYP-treatment condition, but decreased in the chronic condition, potentially due to compensatory changes in neurotrophin signaling or increased urothelial barrier dysfunction in the chronic condition. Our findings demonstrate that these receptors represent additional potent therapeutic targets in mice with cystitis and may be useful in the treatment of interstitial cystitis and other inflammatory disorders of the bladder.

Potentilla chinensis aqueous extract attenuates cyclophosphamide-induced hemorrhagic cystitis in rat model

Cyclophosphamide (CYP) damages all mucosal defence lines and induces hemorrhagic cystitis (HC) leading to detrusor overactivity. Patients who undergo combined chemio-radiotherapy are at higher risk of HC. Potentilla chinensis extract (PCE) prevent oxidative stress-dependent diseases. Thus, the aim of the study was to investigate the effect of PCE on urinary bladder function in CYP-induced HC in preclinical study. 60 rats were divided into 4 groups, as follows: I—control, II—rats with CYP-induced HC, III—rats received PCE in dose of 500 mg/kg, and IV—rats with CYP-induced HC which received PCE in dose of 500 mg/kg. PCE or vehicle were administered orally for 14 days. The cystometry was performed 3 days after the last dose of the PCE. Next, urothelium thickness and oedema measurement and biochemical analyses were performed. Cyclophosphamide induced hemorrhagic cystitis. PCE had no influence on the urinary bladder function and micturition cycles in normal rats. PCE diminished the severity of CYP-induced hemorrhagic cystitis. In the urothelium the cyclophosphamide induced the elevation of CGRP, TNF-α, IL-6, IL-1β, OTC_3, NIT, and MAL. Also, the level of T-H protein, HB-EGF, and ZO1 was decreased. Moreover, the level of ROCK1 and VAChT in detrusor muscle increased. cyclophosphamide caused an increased concentration of BDNF and NGF in the urine. In turn, PCE in cyclophosphamide-induced hemorrhagic cystitis caused a reversal of the described biochemical changes within urothelium, detrusor muscle and urine. PCE attenuates detrusor overactivity. In conclusion, our results revealed that PCE attenuates detrusor overactivity in case of cyclophosphamide-induced hemorrhagic cystitis. The potential properties of PCE appear to be important in terms of preventing of oxidative stress-dependent dysfunction of urinary bladder. PCE may become a potential supportive treatment in patient to whom cyclophosphamide-based chemotherapy is used.

Prevalence, Risk Factors, Pathophysiology, Potential Biomarkers and Management of Feline Idiopathic Cystitis: An Update Review

Feline idiopathic cystitis is a widespread disease in small animal clinics, which mainly presents with urinary signs like dysuria, stranguria, hematuria, pollakiuria, and periuria. The etiopathogenesis of the disease may involve interactions between the environmental stressors, neuroendocrine system and bladder of affected cats. Diagnostic biomarkers have not been tested in clinical studies though they are theoretically feasible, and since the clinical signs of the disease assemble those of other feline lower urinary diseases, its diagnosis is a procedure of exclusion. The primary treatment of the disease is long-term multimodal environmental modification (or enrichment) while anti-anxiety drugs and nutritional supplements are recommended for chronic recurrent cases. Still, many medicines need to be evaluated for their efficacy and safety. This review aims to provide readers with a comprehensive understanding of feline idiopathic cystitis by summarizing and updating studies concerning the prevalence, risk factors, etiological hypotheses, diagnostic procedures, possible treatments, and prognosis of the disease.

Current knowledge and novel frontiers in lower urinary tract dysfunction after spinal cord injury: Basic research perspectives

This review article aims to summarize the recent advancement in basic research on lower urinary tract dysfunction (LUTD) following spinal cord injury (SCI) above the sacral level. We particularly focused on the neurophysiologic mechanisms controlling the lower urinary tract (LUT) function and the SCI-induced changes in micturition control in animal models of SCI. The LUT has two main functions, the storage and voiding of urine, that are regulated by a complex neural control system. This neural system coordinates the activity of two functional units in the LUT: the urinary bladder and an outlet including bladder neck, urethra, and striated muscles of the pelvic floor. During the storage phase, the outlet is closed and the bladder is quiescent to maintain a low intravesical pressure and continence, and during the voiding phase, the outlet relaxes and the bladder contracts to promote efficient release of urine. SCI impairs voluntary control of voiding as well as the normal reflex pathways that coordinate bladder and sphincter function. Following SCI, the bladder is initially areflexic but then becomes hyperreflexic due to the emergence of a spinal micturition reflex pathway. However, the bladder does not empty efficiently because coordination between the bladder and urethral sphincter is lost. In animal models of SCI, hyperexcitability of silent C-fiber bladder afferents is a major pathophysiological basis of neurogenic LUTD, especially detrusor overactivity. Reflex plasticity is associated with changes in the properties of neuropeptides, neurotrophic factors, or chemical receptors of afferent neurons. Not only C-fiber but also Aδ-fiber could be involved in the emergence of neurogenic LUTD such as detrusor sphincter dyssynergia following SCI. Animal research using disease models helps us to detect the different contributing factors for LUTD due to SCI and to find potential targets for new treatments.

Therapeutic effects of nerve growth factor-targeting therapy on bladder overactivity in rats with prostatic inflammation

BACKGROUND

The present study examined the effect of liposomes conjugated with antisense oligonucleotide of nerve growth factor (NGF-OND) on local overexpression of NGF and bladder overactivity using rats with prostatic inflammation (PI).

METHODS

Male Sprague-Dawley rats were divided into three groups: (1) Control group; intact rats, (2) PI-NS group; rats with PI and intravesical instillation of normal saline (NS), (3) PI-OND group; rats with PI and intravesical instillation of NGF-OND. On Day 0, PI was induced by intraprostatic 5%-formalin injection. On Day 14, NGF-OND or NS was instilled directly into the bladder after laparotomy. On Day 28, therapeutic effects of NGF-OND were evaluated by awake cystometry and histological analysis as well as reverse-transcription polymerase chain reaction measurements of messenger RNA (mRNA) levels of NGF in the bladder and prostate, inflammatory markers in the prostate, C-fiber afferent markers, and an A-type K⁺ channel α-subunit (Kv 1.4) in L6-S1 dorsal root ganglia (DRG).

RESULTS

Intravesical NFG-OND treatment reduced PI-induced overexpression of NGF in both bladder and prostate, and reduced PI-induced bladder overactivity evident as longer intercontraction intervals in association with reductions of TRPV1 and TRPA1 mRNA expression levels in DRG. mRNA expression of Kv1.4 in DRG was reduced after PI, but improved in the PI-OND group.

CONCLUSIONS

These results indicate that NGF locally expressed in the bladder is an important mediator inducing bladder overactivity with upregulation of C-fiber afferent markers and downregulation of an A-type K⁺ channel subunit in DRG following PI, and that liposome-based, local NGF-targeting therapy could be effective for not only bladder overactivity and afferent sensitization, but also PI. Thus, local blockade of NGF in the bladder could be a therapeutic modality for male LUTS due to BPH with PI.

An Examination of the Relationship between Urinary Neurotrophin Concentrations and Transcutaneous Electrical Nerve Stimulation (TENS) Used in Pediatric Overactive Bladder Therapy

This article aims to explore changes in urinary concentrations of selected neurotrophins in the course of TENS therapy in children with overactive bladder (OAB). A two-group open-label prospective study was conducted. The intervention group comprised 30 children aged between 5 and 12 years old with OAB refractory to conservative therapy. They received 12 weeks of TENS therapy in a home setting. The urinary neurotrophins, NGF, BDNF, NT3, NT4, were measured by ELISA at baseline and at the end of the TENS therapy. Total urinary neurotrophins levels were standardized to mg of creatinine (Cr). We compared the results with the reference group of 30 participants with no symptoms of bladder overactivity. The results revealed that children with OAB both before and after TENS therapy had higher NGF, BDNF, and NT4 concentrations in total and after normalization to Cr than the reference group in contrast to NT3. The response to the therapy expressed as a decrease of urinary neurotrophins after TENS depended on the age and the presenting symptoms. In conclusion, children older than 8 years of age with complaints of daytime incontinence responded better to TENS.

Urodynamic evaluation of patients with localized prostate cancer before and 4 months after robotic radical prostatectomy

Radical prostatectomy can alter the anatomy of the urinary bladder. We aimed to evaluate bladder function before and 4 months after radical prostatectomy using the urodynamic test and overactive bladder (OAB) symptom score. Among 70 prospectively enrolled patients, 61 patients completed the study. In the urodynamic test, bladder capacity and compliance did not change, the frequency of involuntary detrusor contraction decreased, the maximum flow rate and bladder outlet obstruction index improved, and the maximum urethral closure pressure (MUCP) deteriorated. Further evaluation of urodynamic parameters according to changes in symptoms was made. Although change in bladder compliance was correlated with changes in OAB symptoms, not the relative change of bladder compliance but the relative change in the MUCP was reliable factor when OAB symptoms were deteriorated. In general, prostatectomy did not deteriorate the condition of the detrusor; rather, change in the MUCP could be responsible for postprostatectomy OAB.

The influence of Potentilla chinensis aqueous extract on urinary bladder function in retinyl acetate-induced detrusor overactivity in rats

INTRODUCTION & OBJECTIVES

In overactive bladder (OAB) therapy several herbal medicines presented promising effects, however the results are sparse to provide their efficacy. Herbals may become a popular alternative for OAB therapy. Therefore, we investigated whether Potentilla chinensis extract (PCE) would reverse retinyl acetate (RA)-induced detrusor overactivity (DO).

MATERIAL & METHODS

60 rats were divided into 4 groups, as follows: I - control, II - rats with RA-induced DO, III - rats received PCE in dose of 500 mg/kg, and IV - rats with RA-induced DO which received PCE. PCE or vehicle were administered orally for 14 days. The cystometry and bladder blood flow assessment were performed 3 days after the last dose of the PCE. Then the rats were put into the metabolic cages for 24 h. Next, urothelium thickness measurement and biochemical analyses were performed. < /p><p> Results. Intravesical infusion of RA solution induced DO. PCE had no influence on the urinary bladder function and&nbsp; micturition cycles in normal rats. PCE diminished the severity of RA-induced DO. In the urothelium the RA induced the elevation of ATP, CGRP, substance P, VEGF-A, OTC3, and ERK1/2. The concentration of NOS2, CDH1, and ZO1 decreased. Moreover, RA affected the concentration of SNARE proteins (increased concentration of SNAP23, SNAP25, and SV2A). Also in detrusor the elevated level of ROCK1 and VAChT were observed. In turn, PCE in RA-induced DO caused a reversal of the described biochemical changes within urothelium, detrusor muscle and urine. < /p><p> Conclusions. PCE attenuates detrusor overactivity. The potential mechanisms of action of PCE in the urinary bladder seem to be multifactorial and complex. PCE seems to become a reasonable novel OAB therapy.

Antagonism of proNGF or its receptor p75NTR reverses remodelling and improves bladder function in a mouse model of diabetic voiding dysfunction

AIMS/HYPOTHESIS

Although 80% of diabetic patients will suffer from voiding difficulties and urinary symptoms, defined as diabetic voiding dysfunction (DVD), therapeutic targets and treatment options are limited. We hypothesise that the blockade of the pro-nerve growth factor (NGF)/p75 neurotrophin receptor (p75NTR) axis by an anti-proNGF monoclonal antibody or by a small molecule p75NTR antagonist (THX-B) can restore bladder remodelling (represented by bladder weight) in an animal model of DVD. Secondary outcomes of the study include improvements in bladder compliance, contractility and morphology, as well as in voiding behaviour, proNGF/NGF balance and TNF-α expression.

METHODS

In a streptozotocin-induced mouse model of diabetes, diabetic mice received either a blocking anti-proNGF monoclonal antibody or a p75NTR antagonist small molecule as weekly systemic injections for 4 weeks. Animals were tested at baseline (at 2 weeks of diabetes induction), and after 2 and 4 weeks of treatment. Outcomes measured were voiding function with voiding spot assays and cystometry. Bladders were assessed by histological, contractility and protein expression assays.

RESULTS

Diabetic mice showed features of DVD as early as 2 weeks after diabetes diagnosis (baseline) presented by hypertrophy, reduced contractility and abnormal cystometric parameters. Following treatment initiation, a twofold increase (p < 0.05) in untreated diabetic mouse bladder weight and thickness compared with non-diabetic controls was observed, and this change was reversed by p75NTR antagonism (37% reduction in bladder weight compared with untreated diabetic mice [95% CI 14%, 60%]) after 4 weeks of treatment. However, blocking proNGF did not help to reverse bladder hypertrophy. While diabetic mice had significantly worse cystometric parameters and contractile responses than non-diabetic controls, proNGF antagonism normalised bladder compliance (0.007 [Q1-Q3; 0.006-0.009] vs 0.015 [Q1-Q3; 0.014-0.029] ml/cmH2O in untreated diabetic mice, representing 62% reduction [95% CI 8%, 110%], p < 0.05) and contractility to KCl, carbachol and electrical field stimulation (p < 0.05 compared with the diabetic group) after 2 weeks of treatment. These effects were not observed after 4 weeks of treatment with proNGF antagonist. p75NTR antagonism did not show important improvements in cystometric parameters after 2 weeks of treatment. Slightly improved bladder compliance (0.01 [Q1-Q3; 0.009-0.012] vs 0.013 [Q1-Q3; 0.011-0.016] ml/cmH2O for untreated diabetic mice) was seen in the p75NTR antagonist-treated group after 4 weeks of treatment with significantly stabilised contractile responses to KCl, carbachol and electric field stimulation (p < 0.05 for each) compared with diabetic mice. Bladder dysfunction observed in diabetic mice was associated with a significant increase in bladder proNGF/NGF ratio (3.1 [±1.2] vs 0.26 [±0.04] ng/pg in control group, p < 0.05 at week 2 of treatment) and TNF-α (p < 0.05). The proNGF/NGF ratio was partially reduced (about 60% reduction) with both treatments (1.03 [±0.6] ng/pg for proNGF antibody-treated group and 1.4 [±0.76] ng/pg for p75NTR blocker-treated group after 2 weeks of treatment), concomitant with a significant decrease in the bladder levels of TNF-α (p < 0.05), despite persistent hyperglycaemia.

CONCLUSIONS/INTERPRETATION

Our findings indicate that blockade of proNGF and the p75NTR receptor in diabetes can impede the development and progression of DVD. The reported improvements in morphological and functional features in our DVD model validates the proNGF/p75NTR axis as a potential therapeutic target in this pathology. Graphical abstract.

Effects of an alpha-1d adrenoreceptor antagonist (naftopidil) on bladder dysfunction after radiotherapy in female rats

PURPOSE

Storage-phase bladder dysfunction can develop after pelvic radiotherapy. As the alpha-1d adrenoreceptor (a1d-AR) is dominant in the human detrusor, we aimed to investigate the effect of an a1d-AR antagonist on bladder dysfunction after pelvic radiotherapy in a rat model.

MATERIALS AND METHODS

Twenty-four female Wistar rats were used. Eight rats (14-15 weeks, 250-300 g) were randomized to three groups (normal reference group, radiation alone group and radiation plus naftopidil group). An 18-Gy dose of radiotherapy was applied to the radiation alone and radiation plus naftopidil groups. Naftopidil (20 mg/kg) was administered daily to the radiation plus naftopidil group. Four weeks after radiation, all rats underwent cystometry and were killed for reverse transcription polymerase chain reaction to detect mRNAs [a1d-AR, brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF)], Western blot to detect proteins (a1d-AR, extracellular-signal-regulated kinase, BDNF and VEGF) and immunohistochemistry.

RESULTS

Compared to the radiation alone group, (1) the decrease in the mRNA and protein expression of a1d-AR and VEGF was ameliorated, (2) the increase in the expression of BDNF mRNA and proteins such as extracellular-signal-regulated kinase and BDNF was suppressed, (3) submucosal thickness and vascularity on immunohistochemistry were improved, and (4) the baseline intravesical pressure and intercontraction interval in cystometry were ameliorated in the radiation plus naftopidil group.

CONCLUSION

Administration of an a1d-AR antagonist could improve storage-phase bladder dysfunction after radiotherapy not only by upregulating a1d-AR, which might decrease bladder compliance, but also by enhancing vascularity, which might protect the urinary bladder from chronic ischemic inflammation.

Urinary biomarkers of inflammation and tissue remodeling may predict bladder dysfunction in patients with benign prostatic hyperplasia

PURPOSE

To evaluate the expression of urinary biomarkers of inflammation and tissue remodeling in patients with BPH undergoing surgery and evaluate the association of biomarkers with postoperative urodynamic outcomes MATERIALS AND METHODS: We analyzed urine samples from 71 patients treated with TURP from 2011 to 2017. Urinary levels of epidermal growth factor (EGF), matrix-metalloproteinase-1 (MMP-1), interleukin-6 (IL-6), nerve growth factor (NGF) and monocyte-chemoattractant protein-1 (MCP-1) (by commercial ELISA kit) were measured, adjusted by urinary creatinine (Cr) and analyzed according to patients clinical and urodynamic characteristics (baseline and 12-month postoperative urodynamic) RESULTS: MMP-1/Cr levels were significantly higher among subjects with higher detrusor pressure on preoprative urodynamic. MCP-1/Cr levels were significantly higher amongs subjects with preoperative DO. Preoperative levels of NGF/Cr (0.13 vs 0.08, p = 0.005) and MMP-1/Cr (0.11 vs 0.04, p = 0.021) were predictors of persistent DO 12 months after surgery. The following factors were shown to be useful for predicting the persistence of DO in the postoperative period: NGF/Cr, with an AUC of 0.77 (95% CI 0.62-0.92) (p = 0.006), and MMP-1/Cr, with an AUC of 0.72 (95% CI 0.56-0.88) (p = 0.022).

CONCLUSIONS

MMP-1/Cr was associated with higher detrusor pressure and MCP-1/CR with DO. NGF/Cr and MMP-1/Cr were shown to be predictors of persistent postoperative DO.

A Novel Alternative in the Treatment of Detrusor Overactivity? In Vivo Activity of O-1602, the Newly Synthesized Agonist of GPR55 and GPR18 Cannabinoid Receptors

The aim of the research was to assess the impact of O-1602—novel GPR55 and GPR18 agonist—in the rat model of detrusor overactivity (DO). Additionally, its effect on the level of specific biomarkers was examined. To stimulate DO, 0.75% retinyl acetate (RA) was administered to female rats’ bladders. O-1602, at a single dose of 0.25 mg/kg, was injected intra-arterially during conscious cystometry. Furthermore, heart rate, blood pressure, and urine production were monitored for 24 h, and the impact of O-1602 on the levels of specific biomarkers was evaluated. An exposure of the urothelium to RA changed cystometric parameters and enhanced the biomarker levels. O-1602 did not affect any of the examined cystometric parameters or levels of biomarkers in control rats. However, the O-1602 injection into animals with RA-induced DO ameliorated the symptoms of DO and caused a reversal in the described changes in the concentration of CGRP, OCT₃, BDNF, and NGF to the levels observed in the control, while the values of ERK1/2 and VAChT were significantly lowered compared with the RA-induced DO group, but were still statistically higher than in the control. O-1602 can improve DO, and may serve as a promising novel substance for the pharmacotherapy of bladder diseases.

[Overview of pharmacological mechanisms controlling micturition in the central nervous system]

The functions of the lower urinary tract, to storage and periodically release urine, are dependent on the activity of smooth and striated muscles in the bladder, urethra and external urethral sphincter. This activity is in turn controlled by neural circuits not only in the periphery, but also in the central nervous system (CNS). During urine storage, the outlet is closed and the bladder smooth muscle is quiescent by the neural control mechanism mainly organized in the spinal cord. When bladder volume reaches the micturition threshold, activation of a micturition center in the dorsolateral pons (the pontine micturition center) induces micturition through activation of sacral parasympathetic (pelvic) nerves. The brain rostral to the pons (diencephalon and cerebral cortex) is also involved in excitatory and inhibitory regulation of the micturition reflex. Various transmitters including dopamine, serotonin, norepenephrine, GABA, excitatory and inhibitory amino acids, opioids and acetylcholine are implicated in the modulation of the micturition reflex in the CNS. Therefore, injury or neurodegenerative diseases of the CNS as well as drugs can produce bladder and urethral dysfunctions such as urinary frequency, urgency and incontinence or inefficient bladder emptying.

Effect of Water Avoidance Stress on serum and urinary NGF levels in rats: diagnostic and therapeutic implications for BPS/IC patients

Nerve growth factor (NGF) is thought to play a key role in chronic pain felt by bladder pain syndrome/interstitial cystitis (BPS/IC) patients by activating its high affinity receptor tropomyosin-related kinase subtype A (Trk A). Whether this pathway is also involved in the aggravation of pain sensation during stress events was here investigated. The levels of plasmatic NGF were increased in rats submitted to Water Avoidance Stress test (WAS), compared to controls. The administration of the alpha1A adrenoceptors blocker silodosin prevented the increase of plasmatic NGF. Urinary NGF levels were also moderately increased in animals submitted to WAS. WAS increased pain behaviour score, lowered abdominal mechanical pain threshold and increase voiding bladder reflex activity. These changes were prevented by the administration of TrkA antagonist GW441756. These findings prompt the use of plasmatic NGF as diagnosis tool for chronic visceral painful conditions and opens therapeutic opportunities for TrkA receptors antagonist/NGF sequestration.

Urinary nerve growth factor: a biomarker for detrusor overactivity in children? A meta-analysis and trail sequential analysis

PURPOSE

Based on, previously, a systematic review, urinary nerve growth factor (NGF) has emerged as one potentially noninvasive biomarker for detrusor overactivity (DO) in adults. We performed this systematic review to explore if NGF is a biomarker for DO in children.

METHODS

A literature search was conducted in PubMed, Embase, Web of science, and Cochrane Library. Copies of all relevant articles were retrieved for quality assessment and data abstraction by two reviewers. Primary outcome was pooled standardized mean difference (SMD) for NGF/Cr (NGF normalized to urine creatinine) level between DO group and controls.

RESULTS

Three case-control studies published from 2012 to 2016 were included with 74 patients and 70 controls. Children with DO had a significant higher baseline urinary NGF/Cr level compared to controls (SMD = 2.48, 95%CI = 0.85-4.10, P < 0.01). After treatment, the level of NGF/Cr decreased significantly compared to baseline level at 6th month time points (SMD = 0.94, 95%CI = 0.03-1.86, P = 0.04). We calculated the required information size to 99 patients for comparison of urinary NGF/Cr level between DO and controls by trail sequential analysis (TSA).

CONCLUSION

Based on this systematic review, NGF/Cr may be a noninvasive biomarker for DO in children in the future. However, based on TSA, more original studies are needed to clarify the role of NGF/Cr in the biomarker effect.

Urinary nerve growth factor can predict therapeutic efficacy in children with monosymptomatic nocturnal enuresis

AIM

To determine the urinary levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in children with monosymptomatic nocturnal enuresis (MNE) and evaluate whether these factors can be used as biomarkers for the treatment outcome.

METHODS

NGF and BDNF levels were measured and compared in 38 children (28 boys and 10 girls) with MNE and 25 children (18 boys and 7 girls) with no urinary symptoms were assessed. The mean ages in the patient and control groups were 9 and 10 years, respectively (P = .49). The patients were treated with either alarm or desmopressin therapy.

RESULTS

The urinary NGF/creatinine and BDNF/creatinine ratios were significantly higher in the patient group than in the control group (P = .0003 and P = .0095, respectively). NGF and BDNF levels showed a significant positive correlation (P = .0020, r = 0.40). With respect to the degree of response, 19 patients (50%) showed complete response (CR) or partial response (PR), and 19 patients (50%) showed nonresponse (NR). The urinary NGF/creatinine and BDNF/creatinine ratios were significantly higher in the NR group than in the CR and PR groups (P = .0003 and P = .0003, respectively).

CONCLUSIONS

Urinary NGF/creatinine and BDNF/creatinine ratios were significantly higher in children with MNE than in healthy controls. Urinary NGF/creatinine can be predictive factors of a poor treatment outcome in children with MNE.

Effect of cerebrolysin on bladder function after spinal cord injury in female Wistar rats

OBJECTIVES

To study the effect of cerebrolysin on bladder function after spinal cord injury using functional measurements in rats.

METHODS

A total of 60 female rats were enrolled in this study. After induction of complete transection at T9-T10 spinal vertebrae, cerebrolysin was injected intraperitoneally, and daily in three dosages until 7 days (1 week) and continued until 28 days (4 weeks) in three groups to show the impact of that on the bladder function. Urodynamic parameters were measured in the different groups.

RESULTS

Cerebrolysin injection in a dose of 1 mL/kg for 1 week showed a slight improvement in urodynamic parameters. However, infusion of 2.5 and 5 mL/kg cerebrolysin for 1 week caused an elevation in contractions and a decrease in compliance. In long-term 2.5 mL/kg cerebrolysin injection, an improvement in compliance was observed, despite relative contractions. Furthermore, the bladder pressure pattern in the 2.5 mL/kg infused rats for 4 weeks was similar to the control group, but in the group receiving 5 mL/kg cerebrolysin for 4 weeks, reduced bladder contractions and function were observed.

CONCLUSIONS

Our findings suggest that cerebrolysin might be able to inhibit the emergence of neurogenic detrusor overactivity in spinal cord injured female rats.

Urinary Biomarkers in Overactive Bladder: Revisiting the Evidence in 2019

CONTEXT

In overactive bladder (OAB), after an initial outbreak of research, it is more consensual that biomarkers may be better used to phenotype patients. Herein, we revisit this topic, including some of the most promising biomarkers.

OBJECTIVE

To provide a comprehensive analysis of the actual role of biomarkers in OAB.

EVIDENCE ACQUISITION

A PubMed-based literature search was conducted, including the most relevant articles published in the last 15 yr, on nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), adenosine triphosphate (ATP), genomics, and microbiota as OAB biomarkers. Articles with no full text available or not written in English were excluded. Additional reviews were included.

EVIDENCE SYNTHESIS

Urinary NGF, BDNF, and ATP are increased in many OAB patients. These biomarkers can help identify OAB phenotypes and select the ideal candidates for new therapies directed to neurotrophic and purinergic pathways. Circulating urinary miRNA may be useful for establishing the ideal moment for bladder outlet obstruction relief and will eventually lead to the development of therapeutic agents that inhibit or reverse fibrotic pathways in the bladder. Urinary microbiota seems to be related to OAB symptoms, in particular urgency urinary incontinence, and may have strong implications in the prevention, diagnosis, and treatment of OAB.

CONCLUSIONS

In the future, physicians may consider the use of biomarkers to identify distinct OAB phenotypes, with distinct causal mechanisms, selecting patients for specific target therapies with expected better outcomes.

PATIENT SUMMARY

Overactive bladder biomarkers can be useful for phenotype patients and for selecting more effective target therapies.

BDNF and NGF gene polymorphisms and urine BDNF-NGF levels in children with primary monosymptomatic nocturnal enuresis

INTRODUCTION

The pathophysiology and genetic influences in nocturnal enuresis have not been fully elucidated. Delayed neuronal maturation has been suggested as a pathogenetic mechanism in primary monosymptomatic nocturnal enuresis (PMNE). Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are neurotrophins affecting maturation of the nervous system.

OBJECTIVE

The aim of this preliminary study was to investigate BDNF and NGF gene polymorphisms and urine levels of BDNF and NGF in children with PMNE as a first time.

STUDY DESIGN

The single-nucleotide polymorphisms of BDNF (rs6265:G > A:Val66Met; rs8192466:C > T:Thr2Ile) and NGF (rs6330:C > T:Ala35Val, rs11466112:C > T:Arg221Trp) were investigated by comparing 104 children with PMNE and 140 healthy control subjects. Children with non-PMNE were excluded. DNA isolation and detection of polymorphisms were performed by real-time polymerase chain reaction. In addition, urine BDNF and NGF levels of 47 PMNE and 29 healthy children were measured by enzyme-linked immunosorbent assay method and normalized to urine creatinine (Cr) concentration for comparisons.

RESULTS

There were no differences in genotype and allele frequencies of BDNF rs6265 and NGF rs6330 polymorphisms between patients with PMNE and the control group (P > 0.05). No mutant alleles were found in BDNF rs8192466 and NGF rs11466112 polymorphisms in either group. Children with PMNE had higher urine BDNF/Cr (0.020 ± 0.010 vs 0.010 ± 0.002; P = 0.008) and NGF/Cr ratio (3.01 ± 1.87 pg/mg vs 1.77 ± 0.26 pg/mg; P = 0.002) compared with the control subjects. However, no significant differences were found in BDNF/Cr and NGF/Cr values between GG, GA, and AA genotypes of BDNF rs6265 polymorphism and CC and CT genotypes of NGF rs6330 polymorphism (P > 0.05).

DISCUSSION

In this study, no association of BDNF and NGF gene polymorphisms with PMNE was found, and urine neurotrophin concentrations were not directly influenced by investigated polymorphisms. Although, previously increased urine neurotrophin secretion has been found in detrusor overactivity, bladder inflammation, and dysfunctional voiding, this preliminary results also showed an increase in neurotrophins in PMNE. Higher urine neurotrophin levels may be related to delayed and continued neuronal maturation or increased production of neurotrophins in the bladder. The increased urine neurotrophins in PMNE may be an indicator of increased sensory nerve excitability of the bladder, contributing to the development of enuresis.

CONCLUSION

This study showed that investigated neurotrophin gene polymorphisms did not make a significant contribution to the development of PMNE, but urine levels of neurotrophin gene products were higher in PMNE. Owing to the complexity and heterogeneity of genotype-phenotype relationships in enuresis, further studies are needed in PMNE.

Bladder overactivity and afferent hyperexcitability induced by prostate-to-bladder cross-sensitization in rats with prostatic inflammation

KEY POINTS

There is clinical evidence showing that prostatic inflammation contributes to overactive bladder symptoms in male patients; however, little is known about the underlying mechanisms In this study, we investigated the mechanism that prostatic inflammation causes detrusor overactivity by using a rat model of chemically induced prostatic inflammation. We observed a significant number of dorsal root ganglion neurons with dichotomized afferents innervating both prostate and bladder. We also found that prostatic inflammation induces bladder overactivity and urothelial NGF overexpression in the bladder, both dependent on activation of the pelvic nerve, as well as changes in ion channel expression and hyperexcitability of bladder afferent neurons. These results indicate that the prostate-to-bladder cross-sensitization through primary afferent pathways in the pelvic nerve, which contain dichotomized afferents, could be an important mechanism contributing to bladder overactivity and afferent hyperexcitability induced by prostatic inflammation.

ABSTRACT

Prostatic inflammation is reportedly an important factor inducing lower urinary tract symptoms (LUTS) including urinary frequency, urgency and incontinence in patients with benign prostatic hyperplasia (BPH). However, the underlying mechanisms inducing bladder dysfunction after prostatic inflammation are not well clarified. We therefore investigated the effects of prostatic inflammation on bladder activity and afferent function using a rat model of non-bacterial prostatic inflammation. We demonstrated that bladder overactivity, evident as decreased voided volume and shorter intercontraction intervals in cystometry, was observed in rats with prostatic inflammation versus controls. Tissue inflammation, evident as increased myeloperoxidase activity, and IL-1α, IL-1β, and IL-6 levels inside the prostate, but not in the bladder, following intraprostatic formalin injection induced an increase in NGF expression in the bladder urothelium, which depended on activation of the pelvic nerve. A significant proportion (18-19%) of dorsal root ganglion neurons were double labelled by dye tracers injected into either bladder or prostate. In rats with prostatic inflammation, TRPV1, TRPA1 and P2X2 increased, and Kv1.4, a potassium channel α-subunit that can form A-type potassium (K_A ) channels, decreased at mRNA levels in bladder afferent and double-labelled neurons vs. non-labelled neurons, and slow K_A current density decreased in association with hyperexcitability of these neurons. Collectively, non-bacterial inflammation localized in the prostate induces bladder overactivity and enhances bladder afferent function. Thus, prostate-to-bladder afferent cross-sensitization through primary afferents in the pelvic nerve, which contain dichotomized afferents, could underlie storage LUTS in symptomatic BPH with prostatic inflammation.

Partners in Crime: NGF and BDNF in Visceral Dysfunction

Neurotrophins (NTs), particularly Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF), have attracted increasing attention in the context of visceral function for some years. Here, we examined the current literature and presented a thorough review of the subject. After initial studies linking of NGF to cystitis, it is now well-established that this neurotrophin (NT) is a key modulator of bladder pathologies, including Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) and Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS. NGF is upregulated in bladder tissue and its blockade results in major improvements on urodynamic parameters and pain. Further studies expanded showed that NGF is also an intervenient in other visceral dysfunctions such as endometriosis and Irritable Bowel Syndrome (IBS). More recently, BDNF was also shown to play an important role in the same visceral dysfunctions, suggesting that both NTs are determinant factors in visceral pathophysiological mechanisms. Manipulation of NGF and BDNF improves visceral function and reduce pain, suggesting that clinical modulation of these NTs may be important; however, much is still to be investigated before this step is taken. Another active area of research is centered on urinary NGF and BDNF. Several studies show that both NTs can be found in the urine of patients with visceral dysfunction in much higher concentration than in healthy individuals, suggesting that they could be used as potential biomarkers. However, there are still technical difficulties to be overcome, including the lack of a large multicentre placebo-controlled studies to prove the relevance of urinary NTs as clinical biomarkers.

Blebbistatin, a Myosin II Inhibitor, Exerts Antidepressant-Like Activity and Suppresses Detrusor Overactivity in an Animal Model of Depression Coexisting with Overactive Bladder

Overactive bladder (OAB) coexists with depression in women. Here, we assessed the effects of a 1-week treatment with blebbistatin, a myosin II inhibitor, on changes in behavior and detrusor overactivity (DO) symptoms induced by a 6-week administration of 13-cis-retinoic acid (13-cis-RA), with the aid of the forced swim test (FST), spontaneous locomotor activity test, and in vivo cystometric investigations in female Wistar rats. 13-cis-RA-induced depressive-like behavior and DO symptoms were associated with increased corticotropin-releasing factor (CRF) level in the plasma, prefrontal cortex (PFC), hippocampus (Hp), Barrington’s nucleus (BN), and urinary bladder. Moreover, 13-cis-RA decreased brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) levels in plasma, PFC, Hp, and BN, while it increased BDNF and NGF levels in urinary bladder. Blebbistatin exerted antidepressant-like effect and attenuated changes in the cystometric parameters as well as the central and peripheral levels of CRF, BDNF, and NGF that were induced by 13-cis-RA, while it did not affect urine production, mean, systolic or diastolic blood pressure, or heart rate. The results point to blebbistatin as a potential treatment option for OAB coexisting with depression.

Targeting p75 neurotrophin receptors ameliorates spinal cord injury-induced detrusor sphincter dyssynergia in mice

AIMS

To determine the role of p75 neurotrophin receptor (p75^NTR ) and the therapeutic effect of the selective small molecule p75^NTR modulator, LM11A-31, in spinal cord injury (SCI) induced lower urinary tract dysfunction (LTUD) using a mouse model.

METHODS

Adult female T₈ -T₉ transected mice were gavaged daily with LM11A-31 (100 mg/kg) for up to 6 weeks, starting 1 day before, or 7 days following injury. Mice were evaluated in vivo using urine spot analysis, cystometrograms (CMGs), and external urethral sphincter (EUS) electromyograms (EMGs); and in vitro using histology, immunohistochemistry, and Western blot.

RESULTS

Our studies confirm highest expression of p75^NTRs in the detrusor layer of the mouse bladder and lamina II region of the dorsal horn of the lumbar-sacral (L₆ -S₁ ) spinal cord which significantly decreased following SCI. LM11A-31 prevented or ameliorated the detrusor sphincter dyssynergia (DSD) and detrusor overactivity (DO) in SCI mice, significantly improving bladder compliance. Furthermore, LM11A-31 treatment blocked the SCI-related urothelial damage and bladder wall remodeling.

CONCLUSION

Drugs targeting p75^NTRs can moderate DSD and DO in SCI mice, may identify pathophysiological mechanisms, and have therapeutic potential in SCI patients.

Role of neurogenic inflammation in local communication in the visceral mucosa

Intense research has focused on the involvement of the nervous system in regard to cellular mechanisms underlying neurogenic inflammation in the pelvic viscera. Evidence supports the neural release of inflammatory factors, trophic factors, and neuropeptides in the initiation of inflammation. However, more recently, non-neuronal cells including epithelia, endothelial, mast cells, and paraneurons are likely important participants in nervous system functions. For example, the urinary bladder urothelial cells are emerging as key elements in the detection and transmission of both physiological and nociceptive stimuli in the lower urinary tract. There is mounting evidence that these cells are involved in sensory mechanisms and can release mediators. Further, localization of afferent nerves next to the urothelium suggests these cells may be targets for transmitters released from bladder nerves and that chemicals released by urothelial cells may alter afferent excitability. Modifications of this type of communication in a number of pathological conditions can result in altered release of epithelial-derived mediators, which can activate local sensory nerves. Taken together, these and other findings highlighted in this review suggest that neurogenic inflammation involves complex anatomical and physiological interactions among a number of cell types in the bladder wall. The specific factors and pathways that mediate inflammatory responses in both acute and chronic conditions are not well understood and need to be further examined. Elucidation of mechanisms impacting on these pathways may provide insights into the pathology of various types of disorders involving the pelvic viscera.

Role of proNGF/p75 signaling in bladder dysfunction after spinal cord injury

Loss of bladder control is a challenging outcome facing patients with spinal cord injury (SCI). We report that systemic blocking of pro-nerve growth factor (proNGF) signaling through p75 with a CNS-penetrating small-molecule p75 inhibitor resulted in significant improvement in bladder function after SCI in rodents. The usual hyperreflexia was attenuated with normal bladder pressure, and automatic micturition was acquired weeks earlier than in the controls. The improvement was associated with increased excitatory input to the spinal cord, in particular onto the tyrosine hydroxylase-positive fibers in the dorsal commissure. The drug also had an effect on the bladder itself, as the urothelial hyperplasia and detrusor hypertrophy that accompany SCI were largely prevented. Urothelial cell loss that precedes hyperplasia was dependent on p75 in response to urinary proNGF that is detected after SCI in rodents and humans. Surprisingly, death of urothelial cells and the ensuing hyperplastic response were beneficial to functional recovery. Deleting p75 from the urothelium prevented urothelial death, but resulted in reduction in overall voiding efficiency after SCI. These results unveil a dual role of proNGF/p75 signaling in bladder function under pathological conditions with a CNS effect overriding the peripheral one.

The effect of neutralization of nerve growth factor (NGF) on bladder and urethral dysfunction in mice with spinal cord injury

AIMS

To investigate the role of nerve growth factor (NGF) in lower urinary tract dysfunction in mice with spinal cord injury (SCI).

METHODS

Using 4-week SCI mice, single-filling cystometry and external urethral sphincter (EUS)-electromyography were performed under an awake condition. In some SCI mice, anti-NGF antibodies (10 µg/kg/h) were administered for 1 or 2 weeks before the urodynamic study. NGF levels in the bladder and L6/S1 spinal cord were assayed by ELISA. The transcript levels of P2X receptors and TRP channels in L6/S1 dorsal root ganglia (DRG) were measured by RT-PCR.

RESULTS

In SCI mice, the area under the curve of non-voiding contractions (NVCs) during the storage phase was significantly decreased in both 1- and 2-week anti-NGF antibody-treated SCI groups. However, EUS-electromyogram parameters during voiding were not altered by the treatment. Bladder mucosal and spinal NGF levels were decreased after 2 weeks of anti-NGF antibody treatment. TRPA1 and TRPV1 transcripts in L6/S1 DRG were significantly decreased after 1- or 2-week anti-NGF treatment.

CONCLUSIONS

In SCI mice, NGF is involved in the emergence of NVCs in association with increased expression of TRP receptors that are predominantly found in C-fiber afferent pathways. Thus, NGF targeting treatments could be effective for treating storage problems such as detrusor overactivity after SCI.

Current Pharmacologic Approaches in Painful Bladder Research: An Update

The symptoms of interstitial cystitis (IC)/bladder pain syndrome (BPS) may have multiple causes and involve many contributing factors. Traditional treatments (intravesical instillations) have had a primary focus on the bladder as origin of symptoms without adequately considering the potential influence of other local (pelvic) or systemic factors. Systemic pharmacological treatments have had modest success. A contributing factor to the low efficacy is the lack of phenotyping the patients. Individualized treatment based on is desirable, but further phenotype categorization is needed. There seems to be general agreement that IC is a unique disease and that BPS is a syndrome with multiple pathophysiologies, but this has so far not been not been well reflected in preclinical research with the aim of finding new pharmacological treatments. Current research approaches, including anti-nerve growth factor treatment, anti-tumor necrosis factor-α treatment, activation of SHIP1 (AQX-1125), and P2X3 receptor antagonists, and α₁-adrenoceptor antagonists are potential systemic treatments, implying that not only the bladder is exposed to the administered drug, which may be beneficial if the IC/BPS is a bladder manifestation of a systemic disease, or negative (adverse effects) if it is a local bladder condition. Local treatment approaches such as the antagonism of Toll-like receptors (which still is only experimental) and intravesical liposomes (with positive proof-of-concept), may have the advantages of a low number of systemic adverse effects, but cannot be expected to have effects on symptoms generated outside the bladder. Assessment of which of the treatment approaches discussed in this review that can be developed into useful therapies requires further studies.

PACAP/Receptor System in Urinary Bladder Dysfunction and Pelvic Pain Following Urinary Bladder Inflammation or Stress

Complex organization of CNS and PNS pathways is necessary for the coordinated and reciprocal functions of the urinary bladder, urethra and urethral sphincters. Injury, inflammation, psychogenic stress or diseases that affect these nerve pathways and target organs can produce lower urinary tract (LUT) dysfunction. Numerous neuropeptide/receptor systems are expressed in the neural pathways of the LUT and non-neural components of the LUT (e.g., urothelium) also express peptides. One such neuropeptide receptor system, pituitary adenylate cyclase-activating polypeptide (PACAP; Adcyap1) and its cognate receptor, PAC1 (Adcyap1r1), have tissue-specific distributions in the LUT. Mice with a genetic deletion of PACAP exhibit bladder dysfunction and altered somatic sensation. PACAP and associated receptors are expressed in the LUT and exhibit neuroplastic changes with neural injury, inflammation, and diseases of the LUT as well as psychogenic stress. Blockade of the PACAP/PAC1 receptor system reduces voiding frequency in preclinical animal models and transgenic mouse models that mirror some clinical symptoms of bladder dysfunction. A change in the balance of the expression and resulting function of the PACAP/receptor system in CNS and PNS bladder reflex pathways may underlie LUT dysfunction including symptoms of urinary urgency, increased voiding frequency, and visceral pain. The PACAP/receptor system in micturition pathways may represent a potential target for therapeutic intervention to reduce LUT dysfunction.

BDNF overexpression in the bladder induces neuronal changes to mediate bladder overactivity

Elevated levels of brain-derived neurotrophic factor (BDNF) in urine of overactive bladder (OAB) patients support the association of BDNF with OAB symptoms, but the causality is not known. Here, we investigated the functionality of BDNF overexpression in rat bladder following bladder wall transfection of either BDNF or luciferase (luciferase) transgenes (10 µg). One week after transfection, BDNF overexpression in bladder tissue and elevation of urine BDNF levels were observed together with increased transcript of BDNF, its cognate receptors (TrkB and p75^NTR), and downstream PLCγ isoforms in bladder. BDNF overexpression can induce the bladder overactivity (BO) phenotype which is demonstrated by the increased voiding pressure and reduced intercontractile interval during transurethral open cystometry under urethane anesthesia. A role for BDNF-mediated enhancement of prejunctional cholinergic transmission in BO is supported by the significant increase in the atropine- and neostigmine-sensitive component of nerve-evoked contractions and upregulation of choline acetyltransferase, vesicular acetylcholine transporter, and transporter Oct2 and -α1 receptors. In addition, higher expression of transient receptor channels (TRPV1 and TRPA1) and pannexin-1 channels in conjunction with elevation of ATP and neurotrophins in bladder and also in L6/S1 dorsal root ganglia together support a role for sensitized afferent nerve terminals in BO. Overall, genomic changes in efferent and afferent neurons of bladder induced by the overexpression of BDNF per se establish a mechanistic link between elevated BDNF levels in urine and dysfunctional voiding observed in animal models and in OAB patients.

Urinary biomarkers in patients with detrusor underactivity with and without bladder function recovery

PURPOSE

Detrusor underactivity (DU) is frequently encountered in elderly patients. Part of patients with DU might have bladder function recovery after treatment. This study investigated urinary proteins in these DU patients with and without bladder function recovery.

METHODS

A total of 37 patients with chronic urinary retention and urodynamically proven DU were enrolled. After treatment, 24 DU patients had bladder function recovery whereas 13 had not, after 1-year follow-up. Urine collection at baseline was performed, and the urinary protein including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and prostaglandin E2 (PGE2) were measured by ELISA. Twenty urodynamically normal, 34 detrusor overactivity (DO) and 15 detrusor hyperactivity and inadequate contractility (DHIC) patients served as comparative groups.

RESULTS

Urinary NGF levels were significantly higher than normal in patients with DU (9.2 ± 20.3 vs 1.85 ± 2.9 pg/ml, p = 0.037). Urinary BDNF level was only significantly higher in patients with DU than that of the control group (153 ± 199 vs 77.4 ± 47.7 pg/ml, p = 0.033) but not in patients with DHIC or DO. Compared with the control group, the urinary BDNF level was significantly higher in DU patients with bladder function recovery (190 ± 239 pg/ml, p = 0.033) but not in patients without recovery (85.8 ± 43.7 pg/ml, p = 0.612). The PGE2 level was significantly higher than the control group in DU patients with bladder function recovery (1290 ± 836 pg/ml, p < 0.0001) but not in patients without recovery (383 ± 237 pg/ml, p = 0.130).

CONCLUSION

Patients with DU and higher urinary PGE2 and BDNF levels might have a chance to recover bladder function than those with a lower protein level.

Urothelium update: how the bladder mucosa measures bladder filling

AIM

This review critically evaluates the evidence on mechanoreceptors and pathways in the bladder urothelium that are involved in normal bladder filling signalling.

METHODS

Evidence from in vitro and in vivo studies on (i) signalling pathways like the adenosine triphosphate pathway, cholinergic pathway and nitric oxide and adrenergic pathway, and (ii) different urothelial receptors that are involved in bladder filling signalling like purinergic receptors, sodium channels and TRP channels will be evaluated. Other potential pathways and receptors will also be discussed.

RESULTS

Bladder filling results in continuous changes in bladder wall stretch and exposure to urine. Both barrier and afferent signalling functions in the urothelium are constantly adapting to cope with these dynamics. Current evidence shows that the bladder mucosa hosts essential pathways and receptors that mediate bladder filling signalling. Intracellular calcium ion increase is a dominant factor in this signalling process. However, there is still no complete understanding how interacting receptors and pathways create a bladder filling signal. Currently, there are still novel receptors investigated that could also be participating in bladder filling signalling.

CONCLUSIONS

Normal bladder filling sensation is dependent on multiple interacting mechanoreceptors and signalling pathways. Research efforts need to focus on how these pathways and receptors interact to fully understand normal bladder filling signalling.

Effect of Intravesical Liposome-Based Nerve Growth Factor Antisense Therapy on Bladder Overactivity and Nociception in a Rat Model of Cystitis Induced by Hydrogen Peroxide

The aim of this study was to evaluate whether liposome-based local suppression of nerve growth factor (NGF) in the bladder has effects on bladder hypersensitivity in a rat cystitis model induced by intravesical instillation of hydrogen peroxide (HP). HP (1.5%) was intravesically administered to adult female Sprague-Dawley rats. Liposomes complexed with NGF antisense oligonucleotide (OND) labeled with TYE563 fluorescent tag were intravesically instilled on day 2. Red fluorescence from the TYE 563 tag was observed with fluorescent microscopy on day 3. Four separate groups of rats were used in the following experiments: (a) sham-liposome group, (b) sham-OND group, (c) cystitis-liposome group, and (d) cystitis-OND group. Saline or 1.5% HP was intravesically administered on day 0. Empty liposomes or liposomes-antisense OND were instilled into the bladder on day 2. The following experiments were conducted to evaluate the effect of NGF antisense treatment on day 7: (a) continuous cystometry was performed in an awake condition; (b) pain behavior induced by instillation of resiniferatoxin into the bladder, including licking behavior (lower abdominal licking) and freezing behavior (motionless head-turning toward lower abdomen), was observed; (c) immunohistochemical staining of the bladder and L6 DRG for NGF was performed; (d) the expression of several genes in the bladder was analyzed by reverse transcription polymerase chain reaction (RT-PCR); and (e) after Fast Blue was injected into the bladder wall, Fast Blue-positive or -negative cells in DRG neurons were separately collected by using a laser-capture microdissection method 7 days later. RT-PCR was performed to evaluate gene expressions in captured neuronal cells. The expression of TYE563 was identified only in the urothelial layer. In cystometric investigation, intercontraction intervals (ICI) were significantly (p = 0.001) shorter in the cystitis-liposome group in comparison to the sham-liposome group. ICI was significantly (p = 0.007) longer in the cystitis-OND group compared to the cystitis-liposome group. Comparisons of the sham-liposome and the sham-OND groups showed no significant difference in ICI (p = 0.56). Licking events did not significantly differ among the four groups. In contrast, the cystitis-liposome group showed significantly more freezing events than the sham-liposome group did (p = 0.002). A significant reduction in the number of freezing events was observed in the cystitis-OND group compared to the cystitis-liposome group (p = 0.04). Immunofluorescence staining demonstrated that NGF expression in the mucosa (p = 0.02) and L6 DRG (p = 0.01) was significantly higher in the cystitis-liposome group than it was in the sham-liposome group. The expression of NGF was significantly lower in the mucosa (p = 0.002) and L6 DRG (p = 0.01) in the cystitis-OND group compared to the cystitis-liposome group. RT-PCR showed that the expression of NGF and TRPV1 mRNA in the mucosa was significantly higher in the cystitis-liposome group than it was in the sham-liposome group (p = 0.001 and 0.03, respectively). On the other hand, these gene expressions were significantly lower in the cystitis-OND group than they were in the cystitis-liposome group (p = 0.007 and 0.02, respectively). The cystitis-liposome group showed significantly higher expression of TRPA1, P2X3, and BDNF mRNA in labeled bladder afferent neurons than the sham-liposome group did (p = 0.03, 0.01, and 0.001, respectively). These gene expressions were significantly lower in the cystitis-OND group compared to the cystitis-liposome group (p = 0.04, 0.006, and 0.03, respectively). The study indicated that intravesical application of liposome-NGF antisense OND significantly improved bladder hypersensitivity induced by chemical cystitis in rats. Intravesical treatment with liposome-OND conjugates could be a novel local therapy of hypersensitive bladder disorders such as bladder pain syndrome/interstitial cystitis.

Neurite outgrowth in cultured mouse pelvic ganglia - Effects of neurotrophins and bladder tissue

Neurotrophic factors regulate survival and growth of neurons. The urinary bladder is innervated via both sympathetic and parasympathetic neurons located in the major pelvic ganglion. The aim of the present study was to characterize the effects of the neurotrophins nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) on the sprouting rate of sympathetic and parasympathetic neurites from the female mouse ganglion. The pelvic ganglion was dissected out and attached to a petri dish and cultured in vitro. All three factors (BDNF, NT-3 and NGF) stimulated neurite outgrowth of both sympathetic and parasympathetic neurites although BDNF and NT-3 had a higher stimulatory effect on parasympathetic ganglion cells. The neurotrophin receptors TrkA, TrkB and TrkC were all expressed in neurons of the ganglia. Co-culture of ganglia with urinary bladder tissue, but not diaphragm tissue, increased the sprouting rate of neurites. Active forms of BDNF and NT-3 were detected in urinary bladder tissue using western blotting whereas tissue from the diaphragm expressed NGF. Neurite outgrowth from the pelvic ganglion was inhibited by a TrkB receptor antagonist. We therefore suggest that the urinary bladder releases trophic factors, including BDNF and NT-3, which regulate neurite outgrowth via activation of neuronal Trk-receptors. These findings could influence future strategies for developing pharmaceuticals to improve re-innervation due to bladder pathologies.

Host Responses to Urinary Tract Infections and Emerging Therapeutics: Sensation and Pain within the Urinary Tract

Urinary tract infection (UTI) pathogenesis is understood increasingly at the level of the uropathogens and the cellular and molecular mediators of host inflammatory responses. However, little is known about the mediators of symptoms during UTI and what distinguishes symptomatic events from asymptomatic bacteriuria. Here, we review bladder physiology and sensory pathways in the context of an emerging literature from murine models dissecting the host and pathogen factors mediating pain responses during UTI. The bladder urothelium is considered a mediator of sensory responses and appears to play a role in UTI pain responses. Virulence factors of uropathogens induce urothelial damage that could trigger pain due to compromised bladder-barrier function. Instead, bacterial glycolipids are the major determinants of UTI pain independent of urothelial damage, and the O-antigen of lipopolysaccharide modulates pain responses. The extent of pain modulation by O-antigen can have profound effects, from abolishing pain responses to inducing chronic pain that results in central nervous system features reminiscent of neuropathic pain. Although these effects are largely dependent upon Toll-like receptors, pain is independent of inflammation. Surprisingly, some bacteria even possess analgesic properties, suggesting that bacteria exhibit a wide range of pain phenotypes in the bladder. In summary, UTI pain is a complex form of visceral pain that has significant potential to inform our understanding of bacterial pathogenesis and raises the specter of chronic pain resulting from transient infection, as well as novel approaches to treating pain.