A neurologic basis for the overactive bladder

Effectiveness and safety of moxibustion for alleviating symptoms of overactive bladder: A prospective, randomized controlled, crossover-design, pilot study

BACKGROUND

This study aimed to evaluate trial feasibility and explore the potential efficacy and safety of moxibustion in the treatment of overactive bladder (OAB).

METHOD

A randomized, controlled, cross-over, assessor blinded design was used. This study was conducted in an outpatient department of a university hospital in Republic of Korea. The overall study period was 8 weeks. Participants were randomly allotted to either Group A or Group B. Group A participants underwent 8 to 12 sessions of moxibustion with behavioral training during the first 4 weeks, while the Group B participants received behavioral training only. Over the next 4 weeks, the treatment offered to the 2 groups was reversed (Group A participants received behavioral training only, while Group B participants underwent the moxibustion session with behavioral training). The OAB-validated 8-question awareness tool (OAB-V8), OAB symptom scores (OABSS), visual analog scale (VAS) for lower urinary tract symptoms, and frequency voiding chart were used to assess outcomes. For analysis, we used effect size, measured as Hedge's g, to present descriptive results indicating the actual difference between the groups.

RESULTS

Compared to that in Group B, the Hedge's g of OAB-V8 for the former 4 weeks in Group A was -0.248, that of OABSS was -1.531, and that of VAS was -0.713. During the latter 4 weeks, Group B showed similar effect with g = 0.465, 1.207, and 0.427 for OAB-V8, OABSS, and VAS, respectively, compared to Group A. The portion of nocturnal voiding volume decreased (g = -0965), the mean voiding volume increased (g = 0.690), and the voiding frequency decreased (g = -0.498) with moxibustion.

CONCLUSIONS

Moxibustion might be considered as an alternative for OAB. A full-sized randomized controlled trial may be feasible with minimal modification in outcome measures and comparator population.

OTHER INFORMATION

This clinical trial has been registered on clinicaltrials.gov (NCT02271607).

Lower Urinary Tract Symptoms in Subjects with Subclinical Cerebral White Matter Lesions

Aim

We assessed the impact of cerebral white matter lesions (WMLs) on lower urinary tract symptoms in subjects with normal neurological and cognitive function.

Methods

A cohort of community-dwelling subjects aged ≥65 years were recruited to undergo MRI brain assessment. WMLs were graded using the Fazekas scale from 0 to 3. A separate telephone interview was carried out to assess the urinary symptoms in these subjects using the questionnaire Overactive Bladder-Validated 8-Question Awareness Tool (OAB-V8).

Results

800 community-dwelling elderly subjects were recruited to undergo MRI brain. In this cohort, 431 subjects responded to the telephone interview concerning their urinary symptoms. Among the respondents, 21.1% did not exhibit any WML on their MRI brain. Most of the subjects (52.6%) exhibited grade 1 WML. On logistic regression, age was found to be positively correlated with the Fazekas score (correlation coefficient 0.203, p ≤ 0.01). Using a cutoff of 8 on OAB-V8, 22% of the respondents experienced OAB. Presence of WML, hypertension, or diabetes mellitus was not found to be correlated with storage urinary symptoms or OAB-V8 total score. Multiple logistic regression analysis did not show the presence of WML to be associated with the diagnosis of OAB (adjusted OR 1.13, 95% CI 0.65–1.96, p=0.659).

Conclusions

WML is associated with age and is common in the elderly population. Mild WML is subclinical, with no obvious neurological and urinary symptoms. Our cohort did not demonstrate a relationship between WML and lower urinary tract symptoms.

A biophysically detailed computational model of urinary bladder small DRG neuron soma

Bladder small DRG neurons, which are putative nociceptors pivotal to urinary bladder function, express more than a dozen different ionic membrane mechanisms: ion channels, pumps and exchangers. Small-conductance Ca2+-activated K+ (SKCa) channels which were earlier thought to be gated solely by intracellular Ca2+ concentration ([Ca]i) have recently been shown to exhibit inward rectification with respect to membrane potential. The effect of SKCa inward rectification on the excitability of these neurons is unknown. Furthermore, studies on the role of KCa channels in repetitive firing and their contributions to different types of afterhyperpolarization (AHP) in these neurons are lacking. In order to study these phenomena, we first constructed and validated a biophysically detailed single compartment model of bladder small DRG neuron soma constrained by physiological data. The model includes twenty-two major known membrane mechanisms along with intracellular Ca2+ dynamics comprising Ca2+ diffusion, cytoplasmic buffering, and endoplasmic reticulum (ER) and mitochondrial mechanisms. Using modelling studies, we show that inward rectification of SKCa is an important parameter regulating neuronal repetitive firing and that its absence reduces action potential (AP) firing frequency. We also show that SKCa is more potent in reducing AP spiking than the large-conductance KCa channel (BKCa) in these neurons. Moreover, BKCa was found to contribute to the fast AHP (fAHP) and SKCa to the medium-duration (mAHP) and slow AHP (sAHP). We also report that the slow inactivating A-type K+ channel (slow KA) current in these neurons is composed of 2 components: an initial fast inactivating (time constant ∼ 25-100 ms) and a slow inactivating (time constant ∼ 200-800 ms) current. We discuss the implications of our findings, and how our detailed model can help further our understanding of the role of C-fibre afferents in the physiology of urinary bladder as well as in certain disorders.

Non-invasive Neuromodulation of Spinal Cord Restores Lower Urinary Tract Function After Paralysis

It is commonly assumed that restoration of locomotion is the ultimate goal after spinal cord injury (SCI). However, lower urinary tract (LUT) dysfunction is universal among SCI patients and significantly impacts their health and quality of life. Micturition is a neurologically complex behavior that depends on intact sensory and motor innervation. SCI disrupts both motor and sensory function and leads to marked abnormalities in urine storage and emptying. Current therapies for LUT dysfunction after SCI focus on preventing complications and managing symptoms rather than restoring function. In this study, we demonstrate that Transcutaneous Electrical Spinal Stimulation for LUT functional Augmentation (TESSLA), a non-invasive neuromodulatory technique, can reengage the spinal circuits' active in LUT function and normalize bladder and urethral sphincter function in individuals with SCI. Specifically, TESSLA reduced detrusor overactivity (DO), decreased detrusor-sphincter dyssynergia (DSD), increased bladder capacity and enabled voiding. TESSLA may represent a novel approach to transform the intrinsic spinal networks to a more functionally physiological state. Each of these features has significant clinical implications. Improvement and restoration of LUT function after SCI stand to significantly benefit patients by improving their quality of life and reducing the risk of incontinence, kidney injury and urinary tract infection, all the while lowering healthcare costs.

Basic and clinical aspects of antimuscarinic agents used to treat overactive bladder

Antimuscarinic agents are now widely used as the pharmacological therapy for overactive bladder (OAB) because neuronal (parasympathetic nerve) and non-neuronal acetylcholine play a significant role for the bladder function. In this review, we will highlight basic and clinical aspects of eight antimuscarinic agents (oxybutynin, propiverine, tolterodine, solifenacin, darifenacin, trospium, imidafenacin, and fesoterodine) clinically used to treat urinary dysfunction in patients with OAB. The basic pharmacological characteristics of these eight antimuscarinic agents include muscarinic receptor subtype selectivity, functional bladder selectivity, and muscarinic receptor binding in the bladder and other tissues. The measurement of drug-receptor binding after oral administration of these agents allows for clearer understanding of bladder selectivity by the integration of pharmacodynamics and pharmacokinetics under in vivo conditions. Their central nervous system (CNS) penetration potentials are also discussed in terms of the feasibility of impairments in memory and cognitive function in elderly patients with OAB. The clinical aspects of efficacy focus on improvements in the daytime urinary frequency, nocturia, bladder capacity, the frequency of urgency, severity of urgency, number of incontinence episodes, OAB symptom score, and quality of life (QOL) score by antimuscarinic agents in patients with OAB. The safety of and adverse events caused by treatments with antimuscarinic agents such as dry mouth, constipation, blurred vision, erythema, fatigue, increased sweating, urinary retention, and CNS adverse events are discussed. A dose-dependent relationship was observed with adverse events, because the risk ratio generally increased with elevations in the drug dose of antimuscarinic agents. Side effect profiles may be additive to or contraindicated by other medications.

Efficacy of pelvic floor muscle training in women with overactive bladder syndrome: a systematic review

INTRODUCTION AND HYPOTHESIS

Our objective was to evaluate the effectiveness of pelvic floor muscle training (PFMT) in reducing overactive bladder (OAB) symptoms in women.

METHODS

Searches were performed at MEDLINE, PubMed, Physiotherapy Evidence Database (PEDro), Scielo, and Central Cochrane Library PubMed until January 2017. Controlled trials were researched by two independent reviewers. Eligible studies were restricted to random and controlled clinical trials that investigated the effectiveness of PFMT in decreasing OAB symptoms. Qualitative methodology was evaluated using the PEDro scale. Data was analyzed and interpreted qualitatively.

RESULTS

The final search retrieved eight studies (n = 1161 women with urgency symptoms), which were published between 2002 and 2016. The methodological scores varied between 4 and 7 in the PEDro scale. PFMT, with the objective of controlling urgent micturition, demonstrated improvements in quality of life in women with OAB. Most data in this revision came from small- to moderate-sized trials, with different and inconsistent outcome measures, which could have impacted the end results.

CONCLUSIONS

The literature regarding the effectiveness of PFMT in OAB remains heterogeneous and inconclusive.

Overactive Bladder Syndrome: Evaluation and Management

Overactive bladder (OAB) syndrome is a chronic medical condition which has a major influence on the quality of life in a significant amount of the population. OAB affects performance of daily activities and has an estimated prevalence of 16.5%. Many sufferers do not seek medical help. Moreover, many family physicians and even gynecologists are not familiar with this issue. Usually patients suffer from OAB in advanced age. Nocturia is reported as the most bothersome symptom in the elderly population. The aim of our review was to discuss all aspects of this challenging disorder and suggest tools for assessment and management strategies. Practitioners can easily overlook urinary complains if they not directly queried. We would like to encourage practitioners to give more attention to this issue.

Increased Expression of TREK-1 K+ Channel in the Dorsal Root Ganglion of Rats with Detrusor Overactivity After Partial Bladder Outlet Obstruction

Background

Changes in expression and activity of ion channels are important pathophysiological mechanisms underlying detrusor overactivity (DO) in partial bladder outlet obstruction (PBOO). The objective of this study was to examine the expression of TREK-1 channel in the bladder and central nervous system of DO rats.

Material/Methods

Thirty Sprague-Dawley rats were subjected to PBOO operations and those displaying non-voiding contractions (NVCs) in cystometry were classified as DO. Sham-operated rats without NVCs in cystometry served as controls. The expression and distribution of TREK-1 in the bladder, spinal cord, and dorsal root ganglion (DRG) were detected by real time-PCR, western blot, and immunohistochemistry.

Results

TREK-1 channel expression in the DRG was significantly increased at the mRNA level (11.20±3.762 vs. 3.209±1.505, P<0.01) and protein level (2.195±0.058 vs. 1.713±0.066, P<0.01) in DO rats as compared to control rats. However, the expression of TREK-1 mRNA in the bladder (1.380±0.810 vs. 4.206±3.827, P>0.05) and spinal cord (0.764±0.357 vs. 0.696±0.188, P>0.05) was comparable between the 2 groups. Immunohistochemistry showed enhanced immunoreactive signals of TREK-1 channel in the DRG, but not in the spinal cord and bladder.

Conclusions

TREK-1 channel was upregulated in the DRG of DO rats after chronic PBOO, which might suppress neuronal excitability and play a protective role in bladder overactivity in PBOO.

Is there "brain OAB" and how can we recognize it? International Consultation on Incontinence-Research Society (ICI-RS) 2017

AIMS

In light of mounting evidence supporting the association of brain regions with the control of urine storage and voiding, the high placebo effect in OAB studies as well as certain anecdotal observations from clinical practice with OAB patients, the role of the brain in OAB was explored.

METHODS

At the ICI-RS 2017 meeting, a panel of Functional Urologists and Basic Scientists presented literature data generating a proposal to discuss whether there is "brain OAB" and how we could recognize it.

RESULTS

Existing data point toward organic brain causes of OAB, in particular concerning white matter disease (WMD) and aging, but with currently speculative mechanisms. Imaging techniques have revealed connectivity changes between brain regions which may explain brain-peripheral interactions in OAB patients, further to acknowledged structural and functional changes in the central nervous system (CNS). Furthermore, psychological disorders like stress and depression have been identified as causes of OAB, with animal and human studies proposing a neurochemical and neuroendocrine pathophysiological basis, involving either the serotoninergic system or the hypothalamic-pituitary-adrenal axis. Finally, childhood data suggest that OAB could be a developmental disorder involving the CNS, although childhood OAB could be a different condition than that of adults in many children.

CONCLUSIONS

Future research should aim to identify the pathogenesis of WMD and the aging processes affecting the brain and the bladder, with possible benefits in prevention strategies, as well as connectivity disorders within the CNS, the pathophysiology of OAB in childhood and the neurochemical pathways connecting affective disorders with OAB.

A Method for the Analysis of AP Foot Convexity: Insights into Smooth Muscle Biophysics

Action potential (AP) profiles vary based on the cell type, with cells of the same type typically producing APs with similar shapes. But in certain syncytial tissues, such as the smooth muscle of the urinary bladder wall, even a single cell is known to exhibit APs with diverse profiles. The origin of this diversity is not currently understood, but is often attributed to factors such as syncytial interactions and the spatial distribution of parasympathetic nerve terminals. Thus, the profile of an action potential is determined by the inherent properties of the cell and influenced by its biophysical environment. The analysis of an AP profile, therefore, holds potential for constructing a biophysical picture of the cellular environment. An important feature of any AP is its depolarization to threshold, termed the AP foot, which holds information about the origin of the AP. Currently, there exists no established technique for the quantification of the AP foot. In this study, we explore several possible approaches for this quantification, namely, exponential fitting, evaluation of the radius of curvature, triangulation altitude, and various area based methods. We have also proposed a modified area-based approach (C_X,Y) which quantifies foot convexity as the area between the AP foot and a predefined line. We assess the robustness of the individual approaches over a wide variety of signals, mimicking AP diversity. The proposed (C_X,Y) method is demonstrated to be superior to the other approaches, and we demonstrate its application on experimentally recorded AP profiles. The study reveals how the quantification of the AP foot could be related to the nature of the underlying synaptic activity and help shed light on biophysical features such as the density of innervation, proximity of varicosities, size of the syncytium, or the strength of intercellular coupling within the syncytium. The work presented here is directed toward exploring these aspects, with further potential toward clinical electrodiagnostics by providing a better understanding of whole-organ biophysics.

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.

Analysis of the prevalence of and factors associated with overactive bladder in adult Korean women

Background

Overactive bladder (OAB) is one of the most prevalent lower urinary tract conditions and has been suggested to be related to various factors. We assessed the prevalence of and factors associated with OAB in women based on a large cross-sectional, population-based study of adult Korean women.

Methods

The Korean community health survey (KCHS) of 2012 was reviewed, and 107,950 female participants aged 19 to 107 years were identified for inclusion in this study. The overactive bladder symptom score (OABSS) was used to define and classify OAB as mild, moderate, or severe. Numerous variables, including marital status; physical activity; education and income levels; type of occupation; body mass index (BMI); smoking; alcohol; sleep time; and medical history of hypertension, diabetes mellitus, hyperlipidemia, or cerebral stroke, were evaluated. The correlation of these variables with the prevalence of OAB was analyzed using simple and multiple logistic regression analyses with complex sampling.

Results

The results showed that 5.2% of adult women experienced OAB. Multiple regression analyses showed a significant correlation between the following variables and OAB: older age (adjusted odds ratio [AOR] = 1.44, 95% confidence interval [CI] = 1.39–1.50, P < 0.001 as 10 years older); married status (AOR = 0.83, 95%CI = 0.70–0.96, P = 0.016); lower level of income (AOR = 1.50, 95%CI = 1.34–1.68, P < 0.001); high BMI (AOR = 1.33, 95%CI = 1.23–1.44, P < 0.001); smoking (AOR = 1.24, 95%CI = 1.04–1.47, P < 0.001); long sleep time (AOR = 1.95, 95%CI = 1.69–2.26); and medical history of hypertension (AOR = 1.11, 95%CI = 1.03–1.21, P = 0.011), diabetes mellitus (AOR = 1.38, 95%CI = 1.25–1.53, P < 0.001), hyperlipidemia (AOR = 1.27, 95%CI = 1.16–1.39, P < 0.001), and cerebral stroke (AOR = 2.04, 95%CI = 1.73–2.41, P < 0.001). The level of stress showed a dose-dependent association with OAB (AOR [95%CI] = 3.28 [2.81–3.83] > 2.11 [1.91–2.33] >1.28 [1.16–1.41] for severe > moderate > some stress, respectively, P < 0.001).

Conclusion

The prevalence of OAB was approximately 5.2% among adult Korean women. Older age; high BMI; stress level; sleep duration; levels of income and education; marital status; smoking; and medical history of hypertension, diabetes mellitus, hyperlipidemia, and cerebral stroke were significantly related to OAB in women.

The Impact of Duration of Complaints on Successful Outcome of Sacral Neuromodulation

OBJECTIVES

The study aimed to evaluate whether the duration of complaints in patients with overactive bladder syndrome or non-obstructive urinary retention predicts the outcome of sacral neuromodulation (SNM).

METHODS

All patients that underwent a SNM test period evaluation between 2011 and 2014, were included in this study. The duration of complaints was listed in 3 categories: (a) 0-5 years, (b) 5-10 years and (c) 10 years or longer. Analyses with chi square tests were performed to evaluate whether the duration of complaints are associated with outcome of SNM.

RESULTS

In total, 130 patients were included. Most patients had a complaint duration of 0-5 years (n = 60). The test period was successful in 56% (n = 74) of the total group. Analyses showed that the duration of complaints is not significantly associated with outcome of SNM (p = 0.752), even when subdivided per indication, and also when possible confounders such as age at test and indication are taken into account (p = 0.720).

CONCLUSION

Based on the results of this study, there is no relationship between duration of complaints and SNM outcome. SNM seems to remain a feasible treatment option, despite of possible anatomical or physiological changes within the lower urinary tract.

Clinical epidemiological insights into urinary incontinence

INTRODUCTION AND HYPOTHESIS

Urinary incontinence (UI) is very common and heterogeneous among women with limited knowledge of progression or prognosis. Evidence based on clinical epidemiology can help to better understand the natural history of UI.

METHODS

We examine the challenges of UI definition and its subtypes, its impact on quality of life and health-seeking behavior. We review the proposed pathophysiology of UI subtypes and known risk factors as they relate to our current knowledge of the disease state. Finally, we emphasize the role of epidemiology in the process of acquiring new insight, improving knowledge, and translating this information into clinical practice.

RESULTS

Stress UI is most common overall, but mixed UI is most prevalent in older women. The three UI subtypes have some common risk factors, and others that are unique, but there remains a significant gap in our understanding of how they develop. Although the pathophysiology of stress UI is somewhat understood, urgency UI remains mostly idiopathic, whereas mixed UI is the least studied and most complex subtype. Moreover, there exists limited information on the progression of symptoms over time, and disproportionate UI health-seeking behavior. We identify areas of exploration (e.g., epigenetics, urinary microbiome), and offer new insights into a better understanding of the relationship among the UI subtypes and to develop an integrated construct of UI natural history.

CONCLUSION

Future epidemiological strategies using longitudinal study designs could play a pivotal role in better elucidating the controversies in UI natural history and the pathophysiology of its subtypes leading to improved clinical care.

Incidence and risk factors of recurrence of overactive bladder symptoms after discontinuation of successful medical treatment

Purpose

To identify incidence and risk factors of recurrence after discontinuation of successful antimuscarinic therapy in patients with overactive bladder (OAB).

Materials and Methods

This was a prospective, multicenter trial. Patients who had antimuscarinic agents for more than 12 weeks and showed successful response were enrolled. Successful response was defined as answering 'benefit' for patient perception of treatment benefit and answer lesser than 3 points in patient's perception of bladder condition (PPBC). The enrolled patients discontinued the antimuscarinics, and we evaluated their recurrence with PPBC and OAB symptom score (OABSS) at 1, 3, 6, and 12 months. Primary purpose was to identify the recurrence rate and secondary purpose was to reveal risk factors.

Results

Four hundred forty-one patients enrolled and 371 patients completed 6-month follow-up. The enrolled patients showed 1.6 points in PPBC, 2.9 points in OABSS and 1.4 points in IPSS (quality of life) which represented successful response after using antimuscarinics. The cumulative rates of recurrence were 25.6%, 42.3%, and 52.2% at 1, 3, 6 months, respectively. Among 177 patients who did not show recurrence at 6 months, 41 patients were followed up and 4 patients of the 41 patients (9.7%) showed recurrence at 12 months. On univariate and multivariate analyses of recurrence, OAB wet was the risk factor for recurrence after 6 months of discontinuation.

Conclusions

Discontinuation of antimuscarinic therapy after successful treatment resulted in high recurrence rate with time and OAB wet was the independent risk factor for recurrence.

Pre-and postoperative cerebral blood flow changes in patients with idiopathic normal pressure hydrocephalus measured by computed tomography (CT)-perfusion

In idiopathic normal pressure hydrocephalus (iNPH), the cerebral blood flow (CBF) is of pathophysiological interest and a potential biomarker. Computed tomography perfusion (CTP), an established technique with high spatial resolution and quantitative measurements, has not yet been used in the iNPH context. If CTP were sensitive to the CBF levels and changes in iNPH, this technique might provide diagnostic and prognostic absolute perfusion thresholds. The aim of this work was to determine the applicability of CTP to iNPH. CBF measurements of 18 patients pre- and 17 three months postoperatively, and six healthy individuals (HI) were evaluated in 12 cortical and subcortical regions of interest. Correlations between CBF and symptomatology were analyzed in shunt-responders. Compared to HI, the preoperative CBF in iNPH was significantly reduced in normal appearing and periventricular white matter (PVWM), the lentiform nucleus and the global parenchyma. No CBF differences were shown between responders and non-responders. In responders, the CBF recovered postoperatively by 2.5-32% to approximately the level of HI, but remained significantly decreased in the PVWM of non-responders. The pre- and postoperative CBF of cortical and subcortical regions correlated with the intensity of symptoms. In spite of limited spatial coverage, CTP can measure CBF changes in iNPH.

The combination of herbal medicine Weng-li-tong with Tolterodine may be better than Tolterodine alone in the treatment of overactive bladder in women: a randomized placebo-controlled prospective trial

BACKGROUND

To assess the efficacy and safety of the herbal medicine, Weng-li-tong (WLT) as monotherapy or combined with tolterodine in women with overactive bladder (OAB).

METHODS

A prospective, randomized, single-blind multi-center trial was performed which included 182 OAB patients treated with either placebo (n = 26), WLT (n = 52), tolterodine (n = 52) or WLT plus tolterodine (n = 52). The overactive bladder symptom score (OABSS) and micturition behavior were measured to evaluate treatment efficacy.

RESULTS

In total, 146 patients [placebo (n = 23), WLT (n = 39), tolterodine (n = 41) and WLT plus tolterodine (n = 43)] completed 8 weeks of treatment. Compared to those treated with placebo, patients in three intervention groups showed significant improvements in the OABSS, voiding frequency, average voided volume and urgency incontinence. WLT had a slower onset than tolterodine or combination therapy in reducing urgency incontinence. Compared with tolterodine, WLT had a weaker effect in improving OABSS (P = 0.022) and daily voiding frequency (P = 0.034). The combination therapy had better efficacy than WLT or tolterodine alone in improving the OABSS, voiding frequency and voided volume. No significant differences in the changes in quality of life scores were observed among the three intervention groups. Residual urine increased significantly in tolterodine group (P = 0.004), but not in combination group. WLT resulted in fewer adverse effects than tolterodine such as dry mouth (P = 0.002), weak stream (P = 0.002) and less residual urine (P < 0.001).

CONCLUSIONS

WLT could improve OAB symptoms in women, while it had slower onset and weaker efficacy but fewer adverse effects than tolterodine. The combination of WLT and tolterodine was more efficacious than tolterodine alone in improving OAB symptoms.

TRIAL REGISTRATION

Chinese Clinical Trial Registry [ ChiCTR-IPR-14005626 ]. Date of registration: 7 December 2014.

Neuromodulation of the neural circuits controlling the lower urinary tract

The inability to control timely bladder emptying is one of the most serious challenges among the many functional deficits that occur after a spinal cord injury. We previously demonstrated that electrodes placed epidurally on the dorsum of the spinal cord can be used in animals and humans to recover postural and locomotor function after complete paralysis and can be used to enable voiding in spinal rats. In the present study, we examined the neuromodulation of lower urinary tract function associated with acute epidural spinal cord stimulation, locomotion, and peripheral nerve stimulation in adult rats. Herein we demonstrate that electrically evoked potentials in the hindlimb muscles and external urethral sphincter are modulated uniquely when the rat is stepping bipedally and not voiding, immediately pre-voiding, or when voiding. We also show that spinal cord stimulation can effectively neuromodulate the lower urinary tract via frequency-dependent stimulation patterns and that neural peripheral nerve stimulation can activate the external urethral sphincter both directly and via relays in the spinal cord. The data demonstrate that the sensorimotor networks controlling bladder and locomotion are highly integrated neurophysiologically and behaviorally and demonstrate how these two functions are modulated by sensory input from the tibial and pudental nerves. A more detailed understanding of the high level of interaction between these networks could lead to the integration of multiple neurophysiological strategies to improve bladder function. These data suggest that the development of strategies to improve bladder function should simultaneously engage these highly integrated networks in an activity-dependent manner.

Original Research: Combined model of bladder detrusor smooth muscle and interstitial cells

Although patients with lower urinary tract symptoms constitute a large and still growing population, understanding of bladder detrusor muscle physiology remains limited. Understanding the interactions between the detrusor smooth muscle cells and other bladder cell types (e.g. interstitial cells, IC) that may significantly contribute to coordinating and modulating detrusor contractions represents a considerable challenge. Computer modeling could help to elucidate some properties that are difficult to address experimentally; therefore, we developed in silico models of detrusor smooth muscle cell and interstitial cells, coupled through gap junctions. The models include all of the major ion conductances and transporters described in smooth muscle cell and interstitial cells in the literature. The model of normal detrusor muscle (smooth muscle cell and interstitial cells coupled through gap junctions) completely reproduced the experimental results obtained with detrusor strips in the presence of several pharmacological interventions (ryanodine, caffeine, nimodipine), whereas the model of smooth muscle cell alone (without interstitial cells) failed to reproduce the experimental results. Next, a model of overactive bladder, a highly prevalent clinical condition in both men and women with increasing incidence at older ages, was produced by modifying several processes as reported previously: a reduction of Ca(2+)-release through ryanodine receptors and a reduction of Ca(2+)-dependent K(+)-conductance with augmented gap junctional coupling. This model was also able to reproduce the pharmacological modulation of overactive bladder. In conclusion, a model of bladder detrusor muscle was developed that reproduced experimental results obtained in both normal and overactive bladder preparations. The results indicate that the non-smooth muscle cells of the detrusor (interstitial cells) contribute significantly to the contractile behavior of bladder detrusor muscle and should not be neglected. The model suggests that reduced Ca(2+)-release through ryanodine receptors and Ca(2+)-dependent K(+)-conductance together with augmented gap junctional coupling might play a major role in overactive bladder pathogenesis.

Prevalence of Spina Bifida Occulta and Its Relationship With Overactive Bladder in Middle-Aged and Elderly Chinese People

PURPOSE

To investigate the prevalence of spina bifida occulta (SBO) and its relationship with the presence of overactive bladder (OAB) in middle-aged and elderly people in China.

METHODS

A cross-sectional community-based survey was carried out at 7 communities in Zhengzhou City, China from December 15, 2013 to June 10, 2014, where residents aged over 40 years were randomly selected to participate. All of the participants underwent lumbosacral radiographic analysis and relevant laboratory tests. A questionnaire including basic information, past medical history and present illness, and the OAB symptom score was filled out by all participants. Chi-square tests and logistic regression were used for data analysis with a P-value of <0.05 denoting statistical significance.

RESULTS

A total of 1,061 subjects were qualified for the final statistical analysis (58.8±11.7 years; male, 471 [44.4%]; female, 590 [55.6%]). The overall prevalence of SBO was 15.1% (160 of 1,061): 18.3% (86 of 471) in men and 12.5% (74 of 590) in women. Among these subjects, 13.7% (145 of 1,061) had OAB: 13.2% (62 of 471) in men and 14.1% (83 of 590) in women. The results of logistic regression showed that age, SBO, history of cerebral infarction (HCI), and constipation were risk factors for OAB (P<0.05), while sex, history of childhood enuresis (HCE), body mass index (BMI), and diabetes mellitus (DM) were not (P>0.05). In men, age, SBO, and constipation were risk factors for OAB (P<0.05), while HCE, BMI, DM, HCI, and benign prostate hyperplasia were not (P>0.05). In women, age, SBO, and HCI were risk factors for OAB (P<0.05), while HCE, BMI, DM, vaginal delivery, and constipation were not (P>0.05).

CONCLUSIONS

The prevalence of SBO is high and it is related to OAB in middle-aged and elderly people in China.

The Ameliorating Effect of Exogenous Melatonin on Urinary Bladder Function in Hyperosmolar Bladder Overactivity and its Influence on the Autonomic Nervous System Activity

This study was designed to investigate the effects of melatonin on the bladder hyperactivity in hyperosmolar-induced overactive bladder (OAB) rats. Additionally, the influence of melatonin on the autonomic nervous system (ANS) using heart rate variability (HRV) analysis was assessed. 40 rats were divided into four groups: I – control (n=12), II – rats with hyperosmolar OAB (n=6), III – rats with melatonin pretreatment and hyperosmolar OAB (n=6) and IV – control with melatonin pretreatment (n=6). In group III and IV melatonin in dose of 100 mg/kg was given. HRV measurements in 10 rats, as follow: control (n=2), control after melatonin treatment (n=2), rats with hyperosmolar OAB without (n=3), and after (n=3) melatonin treatment were conducted. This study demonstrates marked influence of melatonin on urinary bladder activity in hyperosmolar-induced OAB rats. These rats showed significantly reduced the detrusor motor overactivity resulting in the improvement of cystometric parameters after melatonin treatment when compared to the control, as follow: a significant increase of intercontraction interval (70 %) and functional bladder capacity (67 %), as well as a decrease of the basal pressure, detrusor overactivity index and motility index of 96 %, 439 % and 40 %, respectively. ANS activity analysis revealed sympathetic overactivity in OAB rats, and parasympathetic superiority in melatonin treated OAB rats. Melatonin treatment in rats with hyperosmolar OAB (group III) caused significant increase of nuHF parameter (from 51.00 ± 25.29 to 76.97 ± 17.43), as well as a decrease of nuLF parameter (from 49.01 ± 25.26 to 23.03 ± 17.43) and LF/HF ratio (from 1.280 ± 0.980 to 0.350 ± 0.330). In conclusion, melatonin suppresses hyperosmolar OAB, and modulates ANS activity by inhibition of the sympathetic drive. Therefore, melatonin may become a useful agent for OAB management.

Central control of visceral pain and urinary tract function

Afferent input from Aδ and C-fibres innervating the urinary bladder are processed differently by the brain, and have different roles in signaling bladder sensation. Aδ fibres that signal bladder filling activate a spino-bulbo-spinal loop, which relays in the midbrain periaqueductal grey (PAG) and pontine micturition centre (PMC). The excitability of this circuitry is regulated by tonic GABAergic inhibitory processes. In humans and socialised animals micturition is normally under volitional control and influenced by a host of psychosocial factors. Higher nervous decision-making in a social context to 'go now' or 'do not go' probably resides in frontal cortical areas, which act as a central control switch for micturition. Exposure to psychosocial stress can have profoundly disruptive influence on the process and lead to maladaptive changes in the bladder. During sleeping the voiding reflex threshold appears to be reset to a higher level to promote urinary continence. Under physiological conditions C-fibre bladder afferents are normally silent but are activated in inflammatory bladder states and by intense distending pressure. Following prolonged stimulation visceral nociceptors sensitise, leading to a lowered threshold and heightened sensitivity. In addition, sensitization may occur within the central pain processing circuitry, which outlasts the original nociceptive insult. Visceral nociception may also be influenced by genetic and environmental influences. A period of chronic stress can produce increased sensitivity to visceral pain that lasts for months. Adverse early life events can produce even longer lasting epigenetic changes, which increase the individual's susceptibility to developing visceral pain states in adulthood.

Inhibitory effects of tibial nerve stimulation on bladder neurophysiology in rats

Tibial nerve stimulation (TNS) is a form of peripheral neuromodulation which has been found effective in treating overactive bladder symptoms, with lesser side effects than first line pharmacotherapy. Despite its widespread clinical use, the underlying mechanism of action is not fully understood. Our aim was to study its effect on the bladder neurophysiology and the trigger mechanism of voiding in the overactive detrusor, simulated by acetic acid (AA) instillation. In urethane anaesthetized male Wistar rats, the tibial nerve was stimulated for 30 min at 5 Hz, pulse width 200 µs and amplitude approximately three times the threshold to induce a slight toe movement. The pressure at which a voiding contraction was triggered (pthres) did not change significantly between the pre- and post-TNS measurements in AA induced detrusor overactivity. It was found that TNS significantly reversed the effects of AA irritation by increasing the bladder compliance and the bladder volume at pthres, as well as suppressed the threshold afferent nerve activity. The slope of the linear relationship between pressure and the afferent activity increased after AA instillation and decreased significantly after stimulation. In addition to its well-known central inhibitory mechanisms, this study has demonstrated that TNS improves bladder storage capacity by delaying the onset of voiding, via an inhibitory effect on the bladder afferent signaling at the peripheral level.

Overactive bladder

Overactive bladder syndrome is highly prevalent, and increasingly so with aging. It is characterized by the presence of urinary urgency, and can be associated with incontinence, increased voiding frequency, and nocturia. Assessment needs to exclude serious medical disorders that might present with similar symptoms, and a bladder diary is an invaluable part of understanding the presentation. Initial management is conservative, comprising education, bladder training, and advice on fluid intake. Drug therapy options include antimuscarinic medications and beta-3 adrenergic receptor agonists. Persistent overactive bladder syndrome, despite initial therapy, requires a review of the patient’s understanding of conservative management and compliance, and adjustment of medications. For refractory cases, specialist review and urodynamic testing should be considered; this may identify detrusor overactivity or increased filling sensation, and needs to exclude additional factors, such as stress incontinence and voiding dysfunction. Botulinum neurotoxin-A bladder injections can be used in severe overactivity, provided the patient is able and willing to do intermittent self-catheterisation, which is necessary in about 5% of treated patients. Sacral nerve stimulation and tibial nerve stimulation are other approaches. Major reconstructive surgery, such as augmentation cystoplasty, is rarely undertaken in modern practice but remains a possibility in extreme cases.

Urinary Retention, Incontinence, and Dysregulation of Muscarinic Receptors in Male Mice Lacking Mras

Here we show that male, but not female mice lacking expression of the GTPase M-Ras developed urinary retention with distention of the bladder that exacerbated with age but occurred in the absence of obvious anatomical outlet obstruction. There were changes in detrusor morphology in Mras^-/- males: Smooth muscle tissue, which exhibited a compact organization in WT mice, appeared disorganized and became increasingly ‘layered’ with age in Mras^-/- males, but was not fibrotic. Bladder tissue near the apex of bladders of Mras^-/- males exhibited hypercontractility in response to the cholinergic agonist carbachol in in vitro, while responses in Mras^-/- females were normal. In addition, spontaneous phasic contractions of detrusors from Mras^-/- males were increased, and Mras^-/- males exhibited urinary incontinence. We found that expression of the muscarinic M2 and M3 receptors that mediate the cholinergic contractile stimuli of the detrusor muscle was dysregulated in both Mras^-/- males and females, although only males exhibited a urinary phenotype. Elevated expression of M2R in young males lacking M-Ras and failure to upregulate M3R with age resulted in significantly lower ratios of M3R/M2R expression that correlated with the bladder abnormalities. Our data suggests that M-Ras and M3R are functionally linked and that M-Ras is an important regulator of male bladder control in mice. Our observations also support the notion that bladder control is sexually dimorphic and is regulated through mechanisms that are largely independent of acetylcholine signaling in female mice.

Enhanced expression of TWIK-related arachidonic acid-activated K+ channel in the spinal cord of detrusor overactivity rats after partial bladder outlet obstruction

Background

Detrusor overactivity (DO) secondary to partial bladder outlet obstruction (PBOO) is closely associated with alteration of ion channels. The objective of this study is to investigate the expression of the TWIK-related arachidonic acid-activated K⁺ channel (TRAAK) in the L6-S1 spinal cord of DO rats after PBOO.

Methods

Female Sprague–Dawley rats undergoing PBOO surgery were screened for DO by cystometry. Sham-operated rats served as controls. The expression of TRAAK in the L6-S1 spinal cord was detected by real-time polymerase chain reaction, western blotting and immunohistochemistry.

Results

DO was successfully induced after chronic PBOO in rats, with an incidence rate of 62.5 %. Compared with sham-operated rats, the expression of TRAAK in the L6-S1 spinal cord of DO rats was significantly increased at the mRNA (1.886 ± 0.710 versus 0.790 ± 0.679, P < 0.05) and protein level (0.510 ± 0.087 versus 0.255 ± 0.107, P < 0.05). Immunohistochemical staining showed increased expression of TRAAK in the dorsal horn and ventral horn of the spinal cord.

Conclusions

Upregulation of TRAAK was observed in the spinal cord of DO rats after chronic PBOO, which may exert a protective effect against DO by suppressing the excitability of neurons.

Anatomy and physiology of the lower urinary tract

Functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. Neural control of micturition is organized as a hierarchic system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brainstem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brainstem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily during the early postnatal period, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults cause re-emergence of involuntary micturition, leading to urinary incontinence. The mechanisms underlying these pathologic changes are discussed.

Posterior tibial nerve stimulation in the management of lower urinary tract symptoms in patients with multiple sclerosis

INTRODUCTION AND HYPOTHESIS

Bladder dysfunction is a frequent symptom complex in patients with multiple sclerosis (MS) and often compromises the patient's quality of life. Pharmacotherapy has been poorly studied in the MS population showing contradictory results and reduced compliance owing to intolerable side effects. A new neuromodulation technique known as percutaneous tibial nerve stimulation (PTNS) has shown good efficacy and safety in the treatment of neurogenic and non-neurogenic lower urinary tract symptoms. In this article we review the literature and critically summarise the scientific evidence supporting the use of PTNS in the treatment of lower urinary tract symptoms (LUTS) in patients with MS.

METHODS

We performed a computer-aided literature search in PubMed and EMBASE up to January 2015 to identify randomised controlled trials, case-control trials and prospective observational cohort studies.

RESULTS

A total of 7 open-label, prospective studies and 313 MS patients were included. Three studies reported clinical and urodynamic outcomes at 3 to 9 months after PTNS; one study assessed the long-term efficacy of PTNS; two studies reported the acute effect of PTNS on urodynamic findings; one study assessed whether motor and sensory responses during PTNS could predict treatment outcome. None of the studies included a control group.

CONCLUSIONS

Despite the very limited data PTNS seems an effective and safe treatment option in the management of LUTS in patients with MS.

[Imaging for urinary incontinence]

BACKGROUND

Ultrasonography and functional cine magnetic resonance imaging (MRI) are noninvasive and x-ray free tools, which are currently widely used in clinical diagnostics and scientific research of male and female urinary incontinence. The increasing use and improving techniques of modern imaging tools are closely linked to rapid development of minimally invasive surgery in patients with urinary incontinence and insights gained in continence mechanisms.

METHODS

Whereas ultrasonography is a cost-efficient and readily available diagnostic tool for a routine use, the more expensive functional MRI, as a tool with more precise visualization of functional interactions and spatial representation of anatomical structures of the pelvic floor, is suitable for complex diagnostic purposes and scientific research. Both tools are already well established for evaluations of the female pelvic floor. For evaluation of the male pelvic floor, and in particular postprostatectomy incontinence, perineal ultrasonography and functional cine MRI are becoming increasingly evident.

CONCLUSION

Further development of both imaging tools will contribute to new insights into the continence mechanism and improve the techniques of radical prostatectomy and minimally invasive surgery of male and female urinary incontinence in the future.

Intracellular Bacterial Communities: A Potential Etiology for Chronic Lower Urinary Tract Symptoms

Patients with persistent lower urinary tract symptoms and negative urine cultures are often difficult to treat. Infection may go undetected in these patients because the concentrations of bacteria in their urine are beneath the threshold of standard urine culture techniques. Empiric treatment may result in temporary relief, followed by recurrent symptoms. Occult and recurrent urinary tract infection may be due to both invasion of the bladder wall by uropathogenic Escherichia coli and the formation of biofilm-like intracellular bacterial communities. This review examines emerging evidence for a role of intracellular bacterial communities in human infection.

Improvement in Spinal Cord Injury-Induced Bladder Fibrosis Using Mesenchymal Stem Cell Transplantation into the Bladder Wall

Experiments on spinal cord injury (SCI) have largely focused on the transplantation of stem cells into injured spinal cords for motor recovery while neglecting to investigate bladder dysfunction. The present study was performed to investigate the effect of B10 human mesenchymal stem cells (hMSCs) directly transplanted into the bladder wall of SCI rats and to determine whether they are capable of inhibiting collagen deposition and improving cystometric parameters in SCI rats. Forty 6-week-old female Sprague–Dawley rats were divided into four groups (group 1: control, group 2: sham operated, group 3: SCI, group 4: SCI rats that received B10 cells). B10 cells were labeled with fluorescent magnetic nanoparticles (MNPs). Four weeks after the onset of SCI, MNP-labeled B10 cells were injected to the bladder wall. Serial magnetic resonance (MR) images were taken immediately after MNP-B10 injection and at 4 weeks posttransplantation. Voiding function was assessed at 4 weeks posttransplantation, and the bladder was harvested. Improvements in bladder fibrosis and bladder function were monitored by molecular MR imaging. Transplantation of B10 cells into the SCI rats markedly reduced their weights and collagen deposition. MR images showed a clear hypointense signal induced by the MNP-labeled B10 cells at 4 weeks posttransplantation. Transplanted B10 cells were found to differentiate into smooth muscle cells. The intercontraction interval decreased, and the maximal voiding pressure increased after SCI but recovered after B10 cell transplantation. Survival of B10 cells was found at 4 weeks posttransplantation using anti-human mitochondria antibody staining and MR imaging. The transplanted B10 cells inhibited bladder fibrosis and ameliorated bladder dysfunction in the rat SCI model. MSC-based cell transplantation may be a novel therapeutic strategy for bladder dysfunction in patients with SCI.

[Physiopathology of overactive bladder syndrome]

The pathophysiology of OAB is complex, multifactorial and still largely unknown. Several pathophysiological mechanisms have been highlighted that may play a different role in different patient groups. There are now experimental evidences that support both the myogenic and neurogenic hypothesis, but in recent years the "integrative" hypothesis has been gaining more and more acceptance, where a disruption in the multiple interactions between different cell types (neurons, urothelium, interstitial cells, myocytes) and network functions represent a central element of lower urinary tract dysfunctions. Of utmost importance, a disorder in the urothelial sensory function and in the urothelial/suburothelial non-neural cholinergic system, favored by age and comorbidities, appears to be crucial for the development of the OAB. Neuroplastic and detrusor changes in OAB are broadly similar to those observed in bladders exposed to outlet obstruction, neuropathies, inflammation or aging, and may be driven by a common urothelial dysfunction. Several signaling substances and their receptors were found to be involved in central pathways of bidirectional communication between the different cell types in the bladder, and were shown to be modified in several animal models of OAB as well as in human models, indicating new potential therapeutic targets.

Bibliometric profile of neurogenic bladder in the literature: a 20-year bibliometric analysis

Neurogenic bladder is a dysfunction of the lower urinary tract caused by nervous system disorder. We investigated the trends in publication of articles under the topic “neurogenic bladder” using bibliometric analysis. Articles on neurogenic bladder, published between 1995 and 2014, were retrieved from the ISI Web of Science citation database. We analyzed the search results for authors, countries, institutions, journals, and top-cited papers. A total of 1,904 articles were retrieved. There was a small increase in the number of articles on neurogenic bladder from 1995 (n = 43) to 2014 (n = 117). The USA was the leading country in the total number of articles (n = 598). However, the number of publications from China has rapidly increased, and China was ranked second in 2014. Emmanuel Chartier-Kastler (n = 65) was the most productive author, and University of Paris VI (Paris 6) (n = 61) was the most productive institution. The Journal of Urology published the greatest number of articles on this topic (n = 285). Articles on neurogenic bladder were often published in a professional journal under the category Urology & Nephrology, Neurosciences & Neurology, or Rehabilitation. Visualization analysis based on co-citation networks was conducted using CiteSpace III. Visualization analysis revealed that the hot spots in neurogenic bladder were botulinum toxin-A, prazosin, bethanechol, and afferent pathways. These findings provide new insight into the publication trends and hot spots in neurogenic bladder.

Research Findings on Overactive Bladder

Several physiopathologic conditions lead to the manifestation of overactive bladder (OAB). These conditions include ageing, diabetes mellitus, bladder outlet obstruction, spinal cord injury, stroke and brain injury, Parkinson's disease, multiple sclerosis, interstitial cystitis, stress and depression. This review has discussed research findings in human and animal studies conducted on the above conditions. Several structural and functional changes under these conditions have not only been observed in the lower urinary tract, but also in the brain and spinal cord. Significant changes were observed in the following areas: neurotransmitters, prostaglandins, nerve growth factor, Rho-kinase, interstitial cells of Cajal, and ion and transient receptor potential channels. Interestingly, alterations in these areas showed great variation in each of the conditions of the OAB, suggesting that the pathophysiology of the OAB might be different in each condition of the disease. It is anticipated that this review will be helpful for further research on new and specific drug development against OAB.

Protein kinase C modulates frequency of micturition and non-voiding contractions in the urinary bladder via neuronal and myogenic mechanisms

Background

Protein Kinase C (PKC) dysfunction is implicated in a variety of smooth muscle disorders including detrusor overactivity associated with frequency and urgency of micturition. In this study, we aimed to evaluate the modulatory effects of endogenous PKC-dependent pathways on bladder storage and emptying function.

Methods

We utilized in vivo cystometry and in vitro organ bath studies using isolated bladder muscle strips (BMS) from rats to measure contractility, intravesical pressure, and voided volume. Both in vitro and in vivo results were statistically analyzed using one-way repeated measures ANOVA between the groups followed by Bonferroni’s post-test, as appropriate (Systat Software Inc., San Jose, CA).

Results

Effects of PKC activators, phorbol-12,13-dibutyrate (PDBu), and phorbol-12,13-myristate (PMA), were concentration-dependent, with high concentrations increasing frequency of micturition, and sensitivity of intramural nerves to electrical field stimulation (EFS), in vitro, while lower concentrations had no effect on BMS sensitivity to EFS. The PKC inhibitors, bisindolylmaleimide1 (Bim-1), (28 nM), and Ro318220 (50 μM) triggered an increase in the number of non-voiding contractions (NVC), and a decrease in the voided volume associated with reduced ability to maintain contractile force upon EFS, but did not affect peak force in vitro. Both low (50 nM) and high PDBu 1 micromolar (1uM) decreased the sensitivity of BMS to carbachol. Application of a low concentration of PDBu inhibited spontaneous contractions, in vitro, and Bim-1-induced NVC, and restored normal voiding frequency during urodynamic recordings in vivo.

Conclusions

In summary, the effects of low PKC stimulation include inhibition of smooth muscle contractile responses, whereas high levels of PKC stimulation increased nerve-mediated contractions in vitro, and micturition contractions in vivo. These results indicate that endogenous PKC signaling displays a concentration-dependent contraction profile in the urinary bladder via both smooth muscle and nerve-mediated pathways.

Bladder recovery by stem cell based cell therapy in the bladder dysfunction induced by spinal cord injury: systematic review and meta-analysis

BACKGROUND

Bladder dysfunction induced by spinal cord injury (SCI) can become problematic and severely impair the quality of life. Preclinical studies of spinal cord injury have largely focused on the recovery of limb function while neglecting to investigate bladder recovery.

OBJECTIVE

The present study was performed to investigate and review the effect of stem cell-based cell therapy on bladder recovery in SCI.

METHODS

We conducted a meta-analysis of urodynamic findings of experimental trials that included studies of stem cell-based cell therapy in SCI. Relevant studies were searched using MEDLINE, EMBASE and Cochrane Library (January 1990 - December 2012). Final inclusion was determined by a urodynamic study involving detailed numerical values. Urodynamic parameters for analysis included voiding pressure, residual urine, bladder capacity and non-voiding contraction (NVC). Meta-analysis of the data, including findings from urodynamic studies, was performed using the Mantel-Haenszel method.

RESULTS

A total of eight studies were included with a sample size of 224 subjects. The studies were divided into different subgroups by different models of SCI. After a stem cell-based cell therapy, voiding pressure (-6.35, p <0.00001, I2 = 77%), NVC (-3.58, p <0.00001, I2 = 82%), residual urine (-024, p = 0.004, I2 = 95%) showed overall significant improvement. Bladder capacity showed improvement after treatment only in the transection type (-0.23, p = 0.0002, I2 = 0%).

CONCLUSION

After stem cell-based cell therapy in SCI, partial bladder recovery including improvement of voiding pressure, NVC, and residual urine was demonstrated. Additional studies are needed to confirm the detailed mechanism and to obtain an ideal treatment strategy for bladder recovery.

Physiological and pathophysiological implications of micromotion activity in urinary bladder function

'Micromotions' is a term signifying the presence of localized microcontractions and microelongations, alongside non-motile areas. The motile areas tend to shift over the bladder surface with time, and the intravesical pressure reflects moment-by-moment summation of the interplay between net contractile force generated by micromotions and general bladder tone. Functionally, the bladder structure may comprise modules with variable linkage, which supports presence of localized micromotions (no functional linkage between modules), propagating contractions (where emergence of linkage allows sequential activation) and the shifting of micromotions over time. Detrusor muscle, interstitial cells and intramural innervation have properties potentially relevant for initiating, coordinating and modulating micromotions. Conceptually, such activity could facilitate the generation of afferent activity (filling state reporting) in the absence of intravesical pressure change and the ability to transition to voiding at any bladder volume. This autonomous activity is an intrinsic property, seen in various experimental contexts including the clinical setting of human (female) overactive bladder. 'Disinhibited autonomy' may explain the obvious micromotions in isolated bladders and perhaps contribute clinically in neurological disease causing detrusor overactivity. Furthermore, any process that could increase the initiation or propagation of microcontractions might be anticipated to have a functional effect, increasing the likelihood of urinary urgency and detrusor overactivity respectively. Thus, models of bladder outlet obstruction, neurological trauma and ageing provide a useful framework for detecting cellular changes in smooth muscle, interstitial cells and innervation, and the consequent effects on micromotions.

Neural control of the lower urinary tract

This article summarizes anatomical, neurophysiological, pharmacological, and brain imaging studies in humans and animals that have provided insights into the neural circuitry and neurotransmitter mechanisms controlling the lower urinary tract. The functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. The neural control of micturition is organized as a hierarchical system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brain stem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brain stem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily in infants and young children until the age of 3 to 5 years, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults can cause the re-emergence of involuntary micturition, leading to urinary incontinence. Neuroplasticity underlying these developmental and pathological changes in voiding function is discussed.