Lack of ultrastructural detrusor changes following endoscopic injection of botulinum toxin type a in overactive neurogenic bladder

The role of botulinum toxin in the management of nonneurogenic overactive bladder in children: Highlights for clinical practice. A systematic review

Overactive bladder (OAB) is the most common voiding dysfunction in children; however, nonneurogenic or idiopathic OAB remains poorly studied. First-line treatment includes conservative measures; however, as many patients are refractory, have adverse effects, or are contraindicated for anticholinergics, new options must be explored. This review covers the use of intravesical botulinum toxin (BoNT) for idiopathic OAB treatment in children, emphasizing its efficacy, safety, differences between toxins, doses, and injection techniques. Clinical results were promising, with all 8 studies reporting good results. All authors used BoNT type A (BoNT-A), either onabotulinum or abobotulinum toxin A. Response rates were variable, with full-response percentages of 32%-60%. As proven by the full-response rates of 50%, repeated injections are as safe and effective as first injections. Only a few cases of urinary tract infection, transient urinary retention, and hematuria have been reported, with no major local or systemic adverse effects. Despite these limitations, evidence encourages and supports BoNT-A use as a safe and effective treatment modality for refractory idiopathic OAB in pediatric settings, regardless of dosage and target toxin. To the best of our knowledge, this is the first systematic review of the use of intravesical BoNT-A for idiopathic OAB treatment in children.

Treatment of neurogenic detrusor overactivity and overactive bladder with Botox (onabotulinumtoxinA): Development, insights, and impact

Neurogenic detrusor overactivity (NDO) is a complication of multiple sclerosis, spinal cord injury (SCI), stroke, head injury, and other conditions characterized by damage to the upper motor neuronal system. NDO often leads to high bladder pressure that may cause upper urinary tract damage and urinary incontinence (UI). Prior to the use of onabotulinumtoxinA, oral anticholinergics and surgical augmentation cystoplasty were the treatment options. Overactive bladder (OAB) is non-neurogenic and affects a much larger population than NDO. Both NDO and OAB negatively impact patients' quality of life (QOL) and confer high health care utilization burdens. Early positive results from pioneering investigators who injected onabotulinumtoxinA into the detrusor of patients with SCI caught the interest of Allergan, which then initiated collaborative clinical trials that resulted in FDA approval of onabotulinumtoxinA 200U in 2011 for NDO and 100U in 2013 for patients with OAB who inadequately respond to or are intolerant of an anticholinergic. These randomized, double-blind, placebo-controlled trials for NDO showed significant improvements in UI episodes, urodynamic parameters, and QOL; the most frequent adverse events were urinary tract infection (UTI) and urinary retention. Similarly, randomized, double-blind, placebo-controlled trials of onabotulinumtoxinA 100U for OAB found significant improvements in UI episodes, treatment benefit, and QOL; UTI and dysuria were the most common adverse events. Long-term studies in NDO and OAB showed sustained effectiveness and safety with repeat injections of onabotulinumtoxinA, the use of which has profoundly improved the QOL of patients failing anticholinergic therapy and has expanded the utilization of onabotulinumtoxinA into smooth muscle.

Botox (onabotulinumtoxinA) mechanism of action

Studies in the 1920s found that botulinum neurotoxin type A (BoNT/A) inhibited the activity of motor and parasympathetic nerve endings, confirmed several decades later to be due to decreased acetylcholine release. The 1970s were marked by studies of cellular mechanisms aided by use of neutralizing antibodies as pharmacologic tools: BoNT/A disappeared from accessibility to neutralizing antibodies within minutes, although it took several hours for onset of muscle weakness. The multi-step mechanism was experimentally confirmed and is now recognized to consist broadly of binding to nerve terminals, internalization, and lysis or cleavage of a protein (SNAP-25: synaptosomal associated protein-25 kDa) that is part of the SNARE (Soluble NSF Attachment protein REceptor) complex needed for synaptic vesicle docking and fusion. Clinical use of the BoNT/A product onabotulinumtoxinA was based on its ability to reduce muscle contractions via inhibition of acetylcholine from motor terminals. Sensory mechanisms of onabotulinumtoxinA have now been identified, supporting its successful treatment of chronic migraine and urgency in overactive bladder. Exploration into migraine mechanisms led to anatomical studies documenting pain fibers that send axons through sutures of the skull to outside the head-a potential route by which extracranial injections could affect intracranial processes. Several clinical studies have also identified benefits of onabotulinumtoxinA in major depression, which have been attributed to central responses induced by feedback from facial muscle and skin movement. Overall, the history of BoNT/A is distinguished by basic science studies that stimulated clinical use and, conversely, clinical observations that spurred basic research into novel mechanisms of action.

Effect of Bladder Injection of OnabotulinumtoxinA on the Central Expression of Genes Associated with the Control of the Lower Urinary Tract: A Study in Normal Rats

To investigate a possible central mechanism of action of Botulinum toxin A (BoNT/A) following injection in the bladder, complementary to the acknowledged peripheral bladder effect, we studied changes in the expression of neuropeptides and receptors involved in lower urinary tract function in the spinal cord (SC) and dorsal root ganglia (DRG) of normal rats following BoNT/A bladder injection. Thirty-six Sprague-Dawley rats, divided into three groups of n = 12, received bladder injections of 2U or 5U OnabotulinumtoxinA (BOTOX^®), or saline. Six animals from each group were sacrificed on days 7 and 14. Expression of Tachykinin 1 (Tac1), capsaicin receptor (TRPV1), neuropeptide Y (NPY), proenkephalin (PENK) and muscarinic receptors M1, M2, M3, was evaluated in the bladder, L6-S1 DRG, and SC segments using real-time PCR and Western blotting. Real-time PCR revealed increased expression of NPY in all tissues except for SC, and increased TRPV1 and PENK expression in DRG and SC, whereas expression of Tac1, M1 and M2 was decreased. Less significant changes were noted in protein levels. These findings suggest that bladder injections of OnabotulinumtoxinA may be followed by changes in the expression of sensory, sympathetic and cholinergic bladder function regulators at the DRG/SC level.

BoNT/A1 Secondary Failure for the Treatment of Neurogenic Detrusor Overactivity: An Ex Vivo Functional Study

Management of neurogenic detrusor overactivity (NDO) remains a clinical priority to improve patients’ quality of life and prevent dramatic urological complications. Intradetrusor injection of onabotulinumtoxinA (BoNT/A1, botulinum neurotoxin A1) is approved as second therapeutic line in these patients, demonstrating a good efficacy. However, a loss of its efficacy over time has been described, with no clear understanding of the underlying mechanisms. This paper aims at shedding new light on BoNT/A1 secondary failure in NDO through functional and structural analysis. Three groups of patients (either non-NDO, NDO with no toxin history or toxin secondary failure) were investigated using an ex vivo bladder strip assay. Detrusor strips were tensed in organ baths and submitted to electrical field stimulation to generate contractions. Recombinant BoNT/A1 was then added at various concentrations and contractions recorded for 4 h. Histology exploring BoNT/A1 targets, fibrosis and neuronal markers was also used. Detrusor strips from patients with BoNT/A1 secondary failure displayed a smaller sensitivity to toxin ex vivo at 3 nM compared to the other groups. Histological evaluation demonstrated the presence of cleaved Synaptosomal-Associated Protein, 25 kDa (c-SNAP25) in the detrusor from the toxin-secondary failure population, indicating some remaining in vivo sensitivity to BoNT/A1 despite the therapeutic escape. Moreover, residual c-SNAP25 did not affect parasympathetic-driven contractions observed ex vivo. This study confirms the slightly lower efficacy of BoNT/A1 in the BoNT/A1 secondary failure NDO group, suggesting that the escape from BoNT/A1 efficacy in NDO occurs at least at the parasympathetic level and could imply compensatory mechanisms for detrusor contraction.

Botulinum Toxin Injection for Medically Refractory Neurogenic Bladder in Children: A Systematic Review

The objective was to evaluate the use of botulinum toxin A (BTX-A) injection in children with medically refractory neurogenic bladder. A systematic review of the literature was conducted using three databases (Medline via PubMed, Cochrane, and EMBASE). Articles evaluating BTX-A in children with neurogenic bladder were collected. The clinical and urodynamic parameters were reviewed for the safety and efficacy evaluation. Sixteen studies were selected into this study and a total of 455 children with medical refractory neurogenic bladder were evaluated. All of the patients had received traditional conservative medications such as antimuscarinics and intermittent catheterization as previous treatment. The duration of treatments ranged from 2 months to 5.7 years. Improvements in incontinence and vesicoureteral reflux were the most common clinical outcomes. The detrusor pressure, bladder capacity and bladder compliance improvement were the most common urodynamic parameters which had been reported. However, patient satisfaction with the procedure remained controversial. There was only a minimal risk of minor adverse effects. In all of the studies, BTX-A injection was well tolerated. In conclusion, BTX-A injection appears to be a safe and effective treatment in the management of medically unresponsive neurogenic bladder in children. There is currently no evidence that the use of BTX-A injection could be used as a first-line therapy for neurogenic bladder in children.

Botulinum toxin A improves neurogenic bladder fibrosis by suppressing transforming growth factor β1 expression in rats

Background

Intradetrusor botulinum toxin A injection is recommended for the treatment of refractory detrusor overactivity (DO) in patients with neurogenic bladder, however, whether it could inhibit neurogenic bladder fibrosis is uncertain. This study aimed to investigate the effect of botulinum toxin A on neurogenic bladder fibrosis and the underlying mechanism.

Methods

Forty eight Female Wistar rats were evenly randomized into 4 groups: Sham, T10 transection, Early and Late groups. The last three groups were subjected to T10 spinal cord transection, while the Sham group was treated with sham surgery. 0.9% saline was injected into the detrusor in the Sham and T10 transection groups simultaneously with the surgery, while 2 U/rat botulinum toxin A was injected into the detrusor simultaneously with the surgery in the Early group and 4 weeks following the surgery in the Late group. Body/bladder weight, cystometric parameters, bladder Hematoxylin-eosin staining were used to evaluate the bladder fibrosis. Western blot and quantitative Real-time PCR were used to evaluate the expression of bladder transforming growth factor β1.

Results

Compared with the T10 transection group, the bladder/body weight was decreased significantly in the Early and Late groups (P<0.05), along with the significant inhibition of non-voiding contraction (NVC) frequency and amplitude (P<0.05), and the significant increase of bladder volume (P<0.05). The detrusor connective tissue percentage (P<0.05) and the expression of transforming growth factor β1 (P<0.05) also decreased significantly in the Early and Late groups. Those changes were more obviously in the Early group than in the Late group.

Conclusions

Intradetrusor botulinum toxin A injection reduced bladder fibrosis in rats with spinal cord injury (SCI), which was more obviously in the Early group than in the Late group. The mechanisms might be mediated by suppression of transforming growth factor β1 (TGF-β1) expression.

Focal arm weakness following intradetrusor botulinum toxin administration in spinal cord injury: Report of two cases

Context: Outpatient Spinal Cord Injury follow-up practice Findings: We present two cases of individuals with tetraplegia who experienced proximal arm weakness temporally related to the administration of intradetrusor onabotulinumtoxinA without other systemic effects. This arm weakness lasted approximately three months in both cases, whereas the effect of the toxin on the bladder lasted for over six months. In one of the cases, the pattern of proximal arm weakness after intravesicular botulinum toxin injection recurred after repeat injection. Conclusion: These cases represent a previously unreported phenomenon of proximal focal weakness associated with the use of intradetrusor chemodenervation. Possible mechanisms for these cases are discussed.

Can clinical and urodynamic parameters predict the occurrence of neutralizing antibodies in therapy failure of intradetrusor onabotulinumtoxin A injections in patients with spinal cord injury?

BACKGROUND

The aim of the study was to clarify whether clinical and/or urodynamic parameters could be used to infer the probability of neutralizing antibody (NAb) formation as a possible cause of therapy failure (non-response, NR) in patients with neurogenic detrusor overactivity (NDO) due to acquired spinal cord injury/disease (SCI/D) treated with intradetrusor botulinum neurotoxin A (BoNT-A) injections.

METHODS

A retrospective chart review was performed of all patients with SCI/D who underwent both intradetrusor onabotulinumtoxin A injections and the determination of neutralizing antibodies against BoNT-A between January 1, 2002, and December 31, 2018. NR was defined as urodynamically confirmed persistent or reappearing NDO.

RESULTS

A total of 2700 BoNT-A injections in 414 patients were ascertained. In 69 patients with primary NR after the first BoNT-A injection (n = 6) or with secondary NR after more than one BoNT-A injection (n = 63), an antibody analysis was performed. Antibody examination showed 36 (52.2%) negative, 5 (7.2%) borderline and 14 (each 20.3%) each of positive and highly positive values. Subgroup analysis indicated a correlation between NAb formation and the duration of BoNT-A therapy (p = 0.015), the mean number of BoNT-A injections (p = 0.011) and the time interval between BoNT-A applications (< 7 months, p = 0.022). Urodynamic data analysis indicate significant differences with cut-off values of MCC (< 225 ml, p = 0.038) and MDP (> 45 cmH2O, p = 0.040). However, in the regression analysis models, the predictive value for the occurrence of NAb was too low (MCC: ROC AUC 0.62, MDP: ROC AUC 0.52) to distinguish with sufficient certainty between NAb-positive and NAb-negative NR patients.

CONCLUSIONS

Despite significant correlations, clinical and urodynamic parameters are only partially suitable for predicting antibody formation against BoNT-A.

Mechanism of Action of OnabotulinumtoxinA in Chronic Migraine: A Narrative Review

Objective

To review the literature on the mechanism of action of onabotulinumtoxinA in chronic migraine.

Background

OnabotulinumtoxinA is a chronic migraine preventive treatment that significantly reduces headache frequency. The traditional mechanism described for onabotulinumtoxinA – reducing muscle contractions – is insufficient to explain its efficacy in migraine, which is primarily a sensory neurological disease.

Methods

A narrative literature review on the mechanism of action of onabotulinumtoxinA in chronic migraine.

Results

Following injection into tissues, onabotulinumtoxinA inhibits soluble N‐ethylmaleimide‐sensitive fusion attachment protein receptor (SNARE)‐mediated vesicle trafficking by cleaving one of its essential proteins, soluble N‐ethylmaleimide‐sensitive fusion attachment protein (SNAP‐25), which occurs in both motor and sensory nerves. OnabotulinumtoxinA inhibits regulated exocytosis of motor and sensory neurochemicals and proteins, as well as membrane insertion of peripheral receptors that convey pain from the periphery to the brain, because both processes are SNARE dependent. OnabotulinumtoxinA can decrease exocytosis of pro‐inflammatory and excitatory neurotransmitters and neuropeptides such as substance P, calcitonin gene‐related peptide, and glutamate from primary afferent fibers that transmit nociceptive pain and participate in the development of peripheral and central sensitization. OnabotulinumtoxinA also decreases the insertion of pain‐sensitive ion channels such as transient receptor potential cation channel subfamily V member 1 (TRPV1) into the membranes of nociceptive neurons; this is likely enhanced in the sensitized neuron. For chronic migraine prevention, onabotulinumtoxinA is injected into 31‐39 sites in 7 muscles of the head and neck. Sensory nerve endings of neurons whose cell bodies are located in trigeminal and cervical ganglia are distributed throughout the injected muscles, and are overactive in people with migraine. Through inhibition of these sensory nerve endings, onabotulinumtoxinA reduces the number of pain signals that reach the brain and consequently prevents activation and sensitization of central neurons postulated to be involved in migraine chronification.

Conclusion

OnabotulinumtoxinA likely acts via sensory mechanisms to treat chronic migraine.

Effect of Botulinum Toxin A on Bladder Pain-Molecular Evidence and Animal Studies

Botulinum toxin A (BTX-A) is a powerful neurotoxin with long-lasting activity that blocks muscle contractions. In addition to effects on neuromuscular junctions, BTX-A also plays a role in sensory feedback loops, suggesting the potentiality for pain relief. Although the only approved indications for BTX-A in the bladder are neurogenic detrusor overactivity and refractory overactive bladder, BTX-A injections to treat bladder pain refractory to conventional therapies are also recommended. The mechanism of BTX-A activity in bladder pain is complex, with several hypotheses proposed in recent studies. Here we comprehensively reviewed properties of BTX-A in peripheral afferent and efferent nerves, the inhibition of nociceptive neurotransmitter release, the reduction of stretch-related visceral pain, and its anti-inflammatory effects on the bladder urothelium. Studies have also revealed possible effects of BTX-A in the human brain. However, further basic and clinical studies are warranted to provide solid evidence-based support in using BTX-A to treat bladder pain.

The Botulinum Treatment of Neurogenic Detrusor Overactivity: The Double-Face of the Neurotoxin

Botulinum neurotoxin (BoNT) can counteract the highly frequent involuntary muscle contractions and the uncontrolled micturition events that characterize the neurogenic detrusor overactivity (NDO) due to supra-sacral spinal cord lesions. The ability of the toxin to block the neurotransmitter vesicular release causes the reduction of contractions and improves the compliance of the muscle and the bladder filling. BoNT is the second-choice treatment for NDO once the anti-muscarinic drugs have lost their effects. However, the toxin shows a time-dependent efficacy reduction up to a complete loss of activity. The cellular mechanisms responsible for BoNT effects exhaustion are not yet completely defined. Similarly, also the sites of its action are still under identification. A growing amount of data suggest that BoNT, beyond the effects on the efferent terminals, would act on the sensory system recently described in the bladder mucosa. The specimens from NDO patients no longer responding to BoNT treatment displayed a significant increase of the afferent terminals, likely excitatory, and signs of a chronic neurogenic inflammation in the mucosa. In summary, beyond the undoubted benefits in ameliorating the NDO symptomatology, BoNT treatment might bring to alterations in the bladder sensory system able to shorten its own effectiveness.

Intradetrusor injection of botulinum toxin A in children: a 10-year single centre experience

PURPOSE

We evaluated the efficacy and safety outcomes of endoscopic intradetrusor botulinum toxin A (BTA) injections for the treatment of children with neuropathic bladder (NB) and non-neuropathic bladder (NNB) with or without detrusor overactivity in a single centre with a retrospective analysis.

METHODS

For the period 2006-2015, children who received BTA in our hospital were analysed. They were divided into group 1, those with underlying NB and group 2, those without a clear neuropathic cause of symptoms (NNB). Data are given as percentages or medians (interquartile range).

RESULTS

Over the study period, 52 children (28 boys, 54%) received BTA, 28 in group 1 (54%; 17 (61%) boys) and 24 in group 2 (46%; 11 (46%) boys). Age at first injection was 11.8 (9.5-14.4) years. After initial injection, 40 (77%) reported symptomatic improvement, 17 (43%) becoming dry. There was no significant difference in response to initial injection between groups (p = 0.11). Duration of improvement after first injection was 7 (5.8-14) months. Twenty-five (48%) had further injections, of whom 3 (12%) were initial non-responders. Ongoing improvement was reported in 20 (80%), 11 (44%) of whom were dry. There was no significant difference in overall response to injections between groups (p = 0.11). Of the 11 non-responders, none (0/3) improved after subsequent injection and 3 (27%) subsequently underwent major urological surgery. Of the 40 who responded, 2 (5%) underwent major surgery.

CONCLUSION

BTA injection produced symptomatic improvement in 77% of our study population, with no significant differences in response between NB and NNB groups. In 95% of those who improved, major urinary tract procedures were avoided during the period studied. None of the initial non-responders improved after subsequent BTA injection. BTA injection is effective and reliable in the management of children with NB and NNB refractory to medical therapy.

Nerve sprouting and neurogenic inflammation characterize the neurogenic detrusor overactive bladder of patients no longer responsive to drug therapies

Urothelium and Lamina Propria (LP) are considered an integrate sensory system which is able to control the detrusor activity. Complete supra-sacral spinal cord lesions cause Neurogenic Detrusor Overactivity (NDO) whose main symptoms are urgency and incontinence. NDO therapy at first consists in anti-muscarinic drugs; secondly, in intra-vesical injection of botulinum toxin. However, with time, all the patients become insensitive to the drugs and decide for cystoplastic surgery. With the aim to get deeper in both NDO and drug's efficacy lack pathogenesis, we investigated the innervation, muscular and connective changes in NDO bladders after surgery by using morphological and quantitative methodologies. Bladder innervation showed a significant global loss associated with an increase in the nerve endings located in the upper LP where a neurogenic inflammation was also present. Smooth muscle cells (SMC) anomalies and fibrosis were found in the detrusor. The increased innervation in the ULP is suggestive for a sprouting and could condition NDO evolution and drug efficacy length. Denervation might cause the SMC anomalies responsible for the detrusor altered contractile activity and intra-cellular traffic and favour the appearance of fibrosis. Inflammation might accelerate these damages. From the clinical point of view, an early anti-inflammatory treatment could positively influence the disease fate.

Muscarinic cholinergic signaling and overactive bladder-like symptoms associated with invasive bladder cancer

The objective of the present study was to explore the association between muscarinic cholinergic signaling and urothelial bladder tumors. Possible associations among overactive bladder (OAB) symptoms and bladder tumors were retrospectively investigated using a multicenter Chinese database with prospectively collected data since 2010. Firstly, it was demonstrated that OAB symptoms, such as urgency, were more severe in patients with invasive bladder cancer and were associated with a reduced prognosis. Following this, muscarinic cholinergic receptor 3 (M3R) expression in urothelium was determined to be lower in invasive cancer tissue than in adjacent non-cancerous tissue, yet M3R upregulation was associated with a reduced progression free survival (PFS) time. Additionally, it was also demonstrated that muscarinic cholinergic receptor 2 (M2R) was upregulated in the sub-urothelium, and this was also associated with a reduced PFS time. Furthermore, it was determined that cholinesterase and acetylcholinesterase were lower in invasive cancer than in non-invasive cancer. In conclusion, the results indicated that M3R expression was downregulated in invasive bladder cancer, which may have a role as a protective anti-oncogene, in contrast to its oncogenic role in numerous other cancer types. Therefore, muscarinic cholinergic signaling may be a novel therapeutic target for treating bladder cancer.

Changes in Management of Poorly Compliant Bladder in Botulinum Toxin A Era

Bladder compliance is a measure of distensibility. Maladies such as myelodysplasia, myelomeningocele, spinal cord injury, multiple sclerosis and obstructive uropathy are known to decrease bladder compliance. Decrease in bladder compliance is a characteristic of neurogenic bladders. The pathophysiology of bladder compliance is complex but ultimately leads to high pressure during filling and storage phases. These high pressures lead to renal impairment, incontinence, and recurrent urinary tract infections. This review presents management of poorly compliant bladders with onabotulinumtoxinA.

Switch to Abobotulinum toxin A may be useful in the treatment of neurogenic detrusor overactivity when intradetrusor injections of Onabotulinum toxin A failed

AIMS

To assess the outcomes of switching to a different brand of botulinum toxin A (BTA, from Botox® to Dysport®) in case of failure of intradetrusor injections (IDI) of Botox® in the treatment of neurogenic detrusor overactivity (NDO).

METHODS

The charts of all patients who underwent a switch to IDI of Dysport® after failure of an IDI of Botox® at six departments of neurourology were retrospectively reviewed. The main outcomes of interest were the bladder diary data and four urodynamic parameters: maximum cystometric capacity (MCC), maximum detrusor pressure (PDET max), and volume at first uninhibited detrusor contraction (UDC).

RESULTS

Fifty-seven patients were included. After the first injection of Dysport®, no adverse events were reported. A significant decrease in number of urinary incontinence episodes per day was observed in 52.63% of patients (P < 0.001) and all patients experienced a reduction in PDET Max (-8.1 cmH20 on average; P = 0.003). MCC significantly increased by a mean of 41.2 (P = 0.02). The proportion of patients with no UDC increased significantly at week 6 after ATA injections (from 15.79% to 43.9%; P = 0.0002). Hence, 32 patients draw clinical and/or urodynamic benefits from the botulinum toxin switch from (56.14%). After a median follow up of 21 months, 87% of responders to BTA switch were still treated successfully with BTA.

CONCLUSION

Most patients refractory to Botox® (56.14%) draw benefits from the switch to Dysport®.

Botulinun A toxin urethral sphincter injection for neurogenic or nonneurogenic voiding dysfunction

Voiding dysfunction due to detrusor underactivity or urethral sphincter dysfunction is a treatment challenge for urologists. Recently, urologists have used botulinum toxin A (BoNT-A) injection into the urethral sphincter to treat voiding dysfunction. This treatment has been found to decrease urethral pressure and postvoid residual volume, and increase voiding efficiency in patients with neurogenic detrusor sphincter dyssynergia, nonneurogenic dysfunctional voiding, and detrusor underactivity. Although not all patients can achieve excellent therapeutic outcomes, patients with idiopathic detrusor underactivity might have recovery of detrusor contractility after urethral sphincter BoNT-A injection. However, urinary incontinence might be a de novo adverse event after treatment. Repeat urethral injection is necessary to maintain therapeutic efficacy. Patients should be fully informed of the limited therapeutic efficacy and possible adverse events prior to treatment. This article reviews recent studies of urethral sphincter BoNT-A treatment for voiding dysfunction.

British Association of Paediatric Urologists consensus statement on the management of the neuropathic bladder

INTRODUCTION

A large number of children with spina bifida develop a neuropathic bladder and this group of patients still forms the largest group of children who require urological management. Although there are published guidelines on the management of the neuropathic bladder, they are not specific to children. It is unsurprising, therefore, that the initial investigation, assessment and management of children with spina bifida vary considerably. The 2014 British Association of Paediatric Urologists (BAPU) meeting was devoted to the management of the neuropathic bladder. The aim was to produce a consensus on the appropriate investigation and management of a child with a neuropathic bladder.

METHODS AND MATERIALS

A questionnaire was devised and the members were polled on their current practice. Six paediatric urology fellows presented an evidence-based literature review on different aspects of the neuropathic bladder. At the end of the session, the members of the organisation present were polled again using the same questions.

RESULTS

The BAPU felt that the use of urodynamics in the neuropathic bladder should be selectively determined by clinical parameters. Regarding CIC, the group was evenly split between universal use or only when poor emptying was established. Oxybutinin was the first-line anticholinergic of choice. Most paediatric urologists routinely used Botox and were happy to use it repeatedly. The surgical intervention most frequently employed was determined to be an ileocystoplasty, with most surgeons deferring the need for surveillance cystoscopy until at least 10 years after surgery.

CONCLUSION

It was felt that a consensus statement is not a guideline or a way to establish best practice; however, it serves as a way of surveying current practice and providing a benchmark for clinicians involved in the management of these patients.

Effect of detrusor botulinum toxin a injection on urothelial dysfunction in patients with chronic spinal cord injury: a clinical and immunohistochemistry study before and after treatment

OBJECTIVE

The objective of this study is to investigate the changes of urothelial junction proteins, apoptosis and suburothelial inflammation after detrusor injection of botulinum toxin A (BoNT-A) in patients with spinal cord injury (SCI) and neurogenic detrusor overactivity (NDO).

METHODS

A total of 26 patients with chronic suprasacral SCI and NDO were enroled. The urothelium was assessed by cystoscopic biopsy at baseline, 3 and 6 months after a single treatment of 300 U BoNT-A into the detrusor. Immunofluorescence staining of E-cadherin, zonula occludens-1 (ZO-1) and tryptase for mast cell activity were performed. Urothelial apoptosis was also evaluated. The differences in urothelial dysfunction were compared between baseline and 3 and 6 months after treatment. Bladder biopsies from patients undergoing anti-incontinence surgery served as controls.

RESULTS

A single 300-U BoNT-A injection into the detrusor significantly decreased detrusor pressure and increased bladder compliance at 3 and 6 months after treatment. Significantly lower E-cadherin and ZO-1 expressions and increased mast cell and apoptotic cell counts were noted in SCI bladders compared with controls (all P<0.001). Significantly greater distributions of E-cadherin (P<0.001) and ZO-1 (P=0.05) expressions were noted 3 months after BoNT-A injection. However, these changes had declined by 6 months after treatment. Activated mast cells and urothelial apoptosis showed no significant differences between baseline and 3 or 6 months.

CONCLUSION

Urothelial dysfunction and adhesive and junction protein concentrations in SCI patients' bladders recovered after BoNT-A treatment. However, this effect decreased with time. Thus, neurogenic inflammation after SCI was not adequately improved after a single BoNT-A injection.

Muscle histopathology in children with spastic cerebral palsy receiving botulinum toxin type A

INTRODUCTION

Botulinum toxin A (BoNTA) is routine treatment for hypertonicity in children with cerebral palsy (CP).

METHODS

This single-blind, prospective, cross-sectional study of 10 participants (mean age 11 years 7 months) was done to determine the relationship between muscle histopathology and BoNTA in treated medial gastrocnemius muscle of children with CP. Open muscle biopsies were taken from medial gastrocnemius muscle and vastus lateralis (control) during orthopedic surgery.

RESULTS

Neurogenic atrophy in the medial gastrocnemius was seen in 6 participants between 4 months and 3 years post-BoNTA. Type 1 fiber loss with type 2 fiber predominance was significantly related to the number of BoNTA injections (r = 0.89, P < 0.001).

CONCLUSIONS

The impact of these changes in muscle morphology on muscle function in CP is not clear. It is important to consider rotating muscle selection or injection sites within the muscle or allowing longer time between injections.

Botulinum toxin type A induces changes in the chemical coding of substance P-immunoreactive dorsal root ganglia sensory neurons supplying the porcine urinary bladder

Botulinum toxin (BTX) is a potent neurotoxin which blocks acetylcholine release from nerve terminals, and therefore leads to cessation of somatic motor and/or parasympathetic transmission. Recently it has been found that BTX also interferes with sensory transmission, thus, the present study was aimed at investigating the neurochemical characterization of substance P-immunoreactive (SP-IR) bladder-projecting sensory neurons (BPSN) after the toxin treatment. Investigated neurons were visualized with retrograde tracing method and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against SP, calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP), neuronal nitric oxide synthase (nNOS), galanin (GAL), calbindin (CB), and somatostatin (SOM). In the control group (n = 6), 45% of the total population of BPSN were SP-IR. Nearly half of these neurons co-expressed PACAP or CGRP (45% and 35%, respectively), while co-localization of SP with GAL, nNOS, SOM or CB was found less frequently (3.7%, 1.8%, 1.2%, and 0.7%, respectively). In BTX-treated pigs (n = 6), toxin-injections caused a decrease in the number of SP-IR cells containing CGRP, SOM or CB (16.2%, 0.5%, and 0%, respectively) and a distinct increase in these nerve cells immunopositive to GAL (27.2%). The present study demonstrates that BTX significantly modifies the chemical phenotypes of SP-IR BPSN.

Evaluation and Management of Neurogenic Bladder: What Is New in China?

Neurogenic bladder (NB) or neurogenic lower urinary tract dysfunction (NLUTD), a dysfunction of the urinary bladder and urethra due to disease of the central nervous system or peripheral nerves, is a major global medical and social problem. Numerous nervous system abnormalities, such as: stroke, Alzheimer's and Parkinson's diseases, traumatic spinal cord injury, spinal cord tumors, congenital spina bifida, and diabetes, can cause NB/NLUTD. There are two major types of bladder control problems associated with NB/NLUTD: the bladder becomes either overactive or underactive depending on the nature, level, and extent of nerve damage. This review specifically focuses on the diagnosis and management of NB/NLUTD in China as well as on recent efforts to treat this disease.

[Therapy of overactive bladder (OAB)]

Overactive bladder (OAB) is a symptom complex which is present in approximately 17% of the European population. It is observed in the presence or absence of incontinence (wet or dry) and is associated with a high degree of psychological stress as well as high costs for the healthcare system. Myogenic, urothelial and neurogenic factors lead to frequently unknown changes of muscular, neural and connective tissue. For the definition, etiology and diagnostics of the disease the previous continuing medical education (CME) article "Diagnosis of overactive bladder (OAB)" should be consulted. In recent years some improvements have been made in OAB-related research, in terms of pathophysiological models and new pharmacological approaches with the development of new therapeutic agents. Besides classical substances, recently approved agents are increasingly being used for the therapy of OAB. Furthermore, non-pharmaceutical approaches and surgical techniques still play an important role in the therapy of OAB.

Changes in chemical coding of sympathetic chain ganglia (SChG) neurons supplying porcine urinary bladder after botulinum toxin (BTX) treatment

Botulinum toxin (BTX) is a neurotoxin used in medicine as an effective drug in experimental therapy of neurogenic urinary bladder disorders. We have investigated the influence of BTX on the chemical coding of sympathetic chain ganglia (SChG) neurons supplying the porcine urinary bladder. The toxin was injected into the wall of the bladder. SChG neurons were visualized by a retrograde tracing method with fluorescent tracer fast blue (FB) and their chemical coding was investigated by double-labelling immunohistochemistry with antibodies against dopamine β-hydroxylase (DβH; a marker of noradrenergic neurons), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin (GAL), Leu⁵-enkephalin (L-ENK) and neuronal nitric oxide synthase (nNOS). In both the control (n = 5) and BTX-treated pigs (n = 5), the vast majority (91 ± 2.3 % and 89.8 ± 2.5 %, respectively) of FB-positive (FB+) nerve cells were DβH+. BTX injections caused a decrease in the number of FB+/DβH+ neurons that were immunopositive to NPY (39.5 ± 4.5 % vs 74.5 ± 11.9 %), VIP (8.9 ± 5.3 % vs 22.3 ± 8.8 %), SOM (5.8 ± 2.3 % vs 17.4 ± 3.7 %) or GAL (0.9 ± 1.2 % vs 5.4 ± 4.4 %) and a distinct increase in the number of FB+/DβH+ neurons that were immunoreactive to L-ENK (3.7 ± 2.9 % vs 1.1 % ± 0.8 %) or nNOS (7.7 ± 3.5 % vs 0.8 ± 0.6 %). Our study provides novel evidence that the therapeutic effects of BTX on the mammalian urinary bladder are partly mediated by SChG neurons.

Dysfunction of lower urinary tract in patients with spinal cord injury

Over the past 50 years, the mortality for urorenal cause in patients with spinal cord injuries (SCI) has decreased from over 75% to 2.3%, as a result of dramatic improvements in the diagnosis and management of lower urinary tract dysfunction (LUTD). The aims of this chapter are to assess the physiopathology of upper and lower motor neuron lesion on bladder and sphincter function after SCI, to give an overview of required clinical and instrumental examination and to discuss treatment modalities. Videourodynamic examination plays a key role in the assessment and follow-up of LUTD in SCI patients, in conjunction with neurophysiological and radiological examinations. The cornerstone of bladder management in SCI is clean intermittent self-catheterization, but often other treatments are needed to achieve full continence, to reduce infections and stone formation, to protect the upper urinary tract from excessive bladder pressure, and to prevent chronic renal failure. Treatments may be pharmacologic (i.e., anticholinergic drugs and botulinum toxin) or surgical (by enterocystoplasty or urinary diversion). In selected cases, neuromodulation and sacral root stimulation can be used to reduce detrusor overactivity and empty the bladder. Management of LUTD in SCI patients requires a deep knowledge of spinal cord medicine and functioning of patients with neurologic disability.

[Endoscopic management of urinary incontinence in neurogenic bladder due to spinal cord lesions in children]

INTRODUCTION

The urological management of urinary incontinence in neurogenic bladder due to spinal cord lesions in children is intended to achieve social continence while preserving the upper urinary tract, combining clean intermittent catheterization with anticholinergic agents. The objective of this study was to report the results on continence of endoscopic management of bladder and/or sphincter of children with failure or intolerance to first intention therapy.

PATIENTS AND METHODS

Of the 364 children followed for neurologic bladder in our institution, 22 required endoscopic management between 2000 and 2012. Urinary incontinence was related to detrusor overactivity in 16 children and sphincter deficiency in 13 children, requiring one or several intradetrusor injections of botulinium toxin-A (BTA) and/or dextranomer/hyaluronic acid (Dx/Ha) injection in the bladder neck. Continence was reassessed between six and eight weeks after the last injection using the Schulte-Baukloh score.

RESULTS

At the end of the mean follow-up of four years, 16 children received 54 injections of BTA and 13 children had 24 injections of Dx/Ha. Social continence, defined as a score between 0 and 1, was acquired quickly after injection of BTA and required to repeat the injections every 8.7 months (6-12) with a very low morbidity. After the first injection of Dx/Ha, 69% of the children improved significantly their incontinence score (from 1 to 0 or from 2 or 3 to 1) with better results for girls.

CONCLUSION

An appropriate endoscopic management has enabled an improvement of the continence of two-thirds of children who fail first intention treatment for their neurogenic bladder. This is an alternative to delay or avoid major surgery.

Therapeutic outcome and patient adherence to repeated onabotulinumtoxinA detrusor injections in chronic spinal cord-injured patients and neurogenic detrusor overactivity

BACKGROUND/PURPOSE

To investigate the continuous therapeutic effects and urinary incontinence severity after repeated detrusor injections of 200-U of onabotulinumtoxinA (BoNT-A) in chronic spinal cord-injured (SCI) patients.

METHODS

Between 2006 and 2010, patients with chronic SCI and refractory neurogenic detrusor overactivity (DO) were treated with repeated sets of 200-U BoNT-A injected into 20 sites every 6 months. All patients underwent urological examinations and video-urodynamic studies at baseline and after each BoNT-A treatment. The outcomes were measured using Urogenital Distress Inventory 6-item short form (UDI-6) for urinary incontinence. The severity of urinary incontinence and urodynamic parameters were compared after each BoNT-A injection.

RESULTS

A total of 59 SCI patients with a mean age of 42.1 ± 13.1 years were enrolled. The UDI-6 incontinence scores persistently improved for up to three injections. The rate of dryness and mild incontinence reported by patients persistently improved from 25.4% at baseline to 74% at 3 months after the fourth injection, but decreased slightly after the fourth injection. The overall satisfaction rate after single or repeated injections was 59.3% (35 patients), and the failure rate was 33.9% (20 patients), and discontinuation rate owing to adverse events (2 recurrent UTI, 2 autonomic dysreflexia) was 6.8% (4 patients). Among the 20 patients who reported failure to treatment, 10 patients (16.9%) reported no significant improvement after one or repeated injections, eight converted to augmentation enterocystoplasty.

CONCLUSION

Repeated 200-U BoNT-A injections every 6 months for neurogenic DO in chronic SCI patients provided a satisfactory initial outcome. However, only 20% patients continued the repeated treatment.

Effect of botulinum toxin A on urothelial-release of ATP and expression of SNARE targets within the urothelium

AIMS

Botulinum neurotoxin serotype A (BoNT/A) has emerged as an effective treatment of urinary bladder overactivity. Intravesical lipotoxin (BoNT/A delivery using liposomes), which may target the urothelium, is effective in blocking acetic acid induced hyperactivity in animals. The objective of this study was to assess the possible site of toxin action within the urothelium.

METHODS

We examined expression of the toxin receptor (SV2) and its cleavage targets (SNAP-25 and SNAP-23) within urothelium as well as effects of the toxin on mechanically evoked release of ATP from cultured rat urothelial cells. ATP release was measured using the luciferin-luciferase assay; we examined expression of SNAP-23 and -25 in urothelial cells and mucosa of rat and human bladders.

RESULTS

BoNT/A (1.5 U; 1-3 hr) blocked hypotonic evoked release of urothelial ATP, without affecting morphology. The expression of protein targets for BoNT/A binding (SV2) was detected in human and rat bladder mucosa and catalytic action (SNAP-23, -25) in urothelial cells and mucosa (differed in intensity) from rat and human bladder. Incubation of cultured (rat) urothelial cells with BoNT/A decreased expression levels of both SNAP-23 (44%) and SNAP-25 (80%).

CONCLUSIONS

Our findings reveal that the bladder urothelium expresses the intracellular targets and the binding protein for cellular uptake of BoNT/A; and that the toxin is able to suppress the levels of these targets as well as hypotonic-evoked ATP release. These data raise the possibility that intravesical treatment with BoNT/A suppresses bladder reflex and sensory mechanisms by affecting a number of urothelial functions including release of transmitters.

Use of botulinum toxin in individuals with neurogenic detrusor overactivity: state of the art review

BACKGROUND

Botulinum neurotoxin (BoNT) injection into the bladder wall has been shown to be an effective alternative to anticholinergic (antimuscarinic) medications and more invasive surgery in those with multiple sclerosis and spinal cord injury with neurogenic detrusor overactivity (NDO) and urinary incontinence who are not tolerating anticholinergic medications. In August 2011, Botox(®) (onabotulinumtoxinA) received Food and Drug Administration (FDA) approval for this use. Clinically, intradetrusor injection of BoNT has been found to decrease urinary incontinence and improve quality of life. Its impact on urodynamic parameters is an increase in the maximum cystometric (bladder) capacity and decrease in the maximum detrusor pressures. The most common side effects are urinary tract infections and urinary retention. There have been rare reports and a black box warning of distant spread of BoNT. BoNT has gained popularity because of its effectiveness and long duration of action, relative ease of administration, easy learning curve, reproducibility of results on repeated administration, and low incidence of complications.

OBJECTIVE

To discuss the structure and function, mechanisms of action, clinical and urodynamic studies, injection technique, potential beneficial and adverse effects, and potential areas of research of BoNT.

METHODS

Literature search focused on botulinum toxin in MEDLINE/PubMed. Search terms included botulinum toxin, neurogenic bladder, NDO, botox bladder, botox spinal cord injury, botox, FDA, botox side effects. All papers identified were English language, full-text papers. In addition, English abstracts of non-English papers were noted. The reference list of identified articles was also searched for further papers.

CONCLUSION

Botulinum toxin is an alternative treatment for individuals with NDO who fail to tolerate anticholinergic medications. Its popularity has increased because of the literature, which has supported its effectiveness, safety, easy use and learning curve, reproducibility of results on repeated use, and recent FDA approval of Botox(®) (onabotulinumtoxinA).

Long-term follow-up after botulinum toxin A (BTX-A) injection into the detrusor for treatment of neurogenic detrusor hyperactivity in children

Purpose

To prove the long-term efficacy of BTX-A injection in the management of children with neurogenic detrusor hyperactivity.

Materials and methods

28 out of 145 children with neurogenic bladder (15 male and 13 female, mean age 10.7 years) who were treated between 2002 and 2010 and became non-responders to conservative treatment were included into the retrospective study.

We injected 10-12 U/kg of BTX-A (Botox^®) into the detrusor at 20-30 sites, sparing the trigone. The mean follow-up was 48 months (range 6-84 months).

Results

Group 1. 14 patients had a single injection of BTX-A. Five of them were successful.

Mean bladder reflex volume increased (from 62.9 to 117.5 ml), maximum detrusor pressure decreased (from 59 to 37.5 cm H₂O), detrusor compliance increased (from 4.8 to 9.5 ml/cm H₂O), and leak-point-pressure decreased (from 46.5 to 24.2 cm H₂O). Four patients did not respond and were treated by ileocystoplasty. Another five were lost to follow-up. Group 2. 14 patients had repeated (mean 2.5) injections of BTX-A with a mean interval of 13.7 months. In thirteen patients, urodynamic parameters of the first and last injection were similar to those obtained in Group 1, showing a good response. One patient received an ileocystoplasty.

Conclusion

BTX-A is a safe alternative in the treatment of detrusor hyperactivity in children with myelomeningocele (MMC). The efficacy lasted a mean of 12 months and urodynamic response was unchanged even after several injections. In our series, 21.7% of children with severe low-compliance bladders were non-responders.

The influence of botulinum toxin type A (BTX) on the immunohistochemical characteristics of noradrenergic and cholinergic nerve fibers supplying the porcine urinary bladder wall

Botulinum toxin (BTX) belongs to a family of neurotoxins which strongly influence the function of autonomic neurons supplying the urinary bladder. Accordingly, BTX has been used as an effective drug in experimental therapies of a range of neurogenic bladder disorders. However, there is no detailed information dealing with the influence of BTX on the morphological and chemical properties of nerve fibres supplying the urinary bladder wall. Therefore, the present study investigated, using double-labeling immunohistochemistry, the distribution, relative frequency and chemical coding of cholinergic and noradrenergic nerve fibers supplying the wall of the urinary bladder in normal female pigs (n = 6) and in the pigs (n = 6) after intravesical BTX injections. In the pigs injected with BTX, the number of adrenergic (DbetaH-positive) nerve fibers distributed in the bladder wall (urothelium, submucosa and muscle coat) was distinctly higher while the number of cholinergic (VAChT-positive) nerve terminals was lower than that found in the control animals. Moreover, the injections of BTX resulted in some changes dealing with the chemical coding of the adrenergic nerve fibers. In contrast to the normal pigs, in BTX injected animals the number of DbetaH/NPY- or DbetaH/CGRP-positive axons was higher in the muscle coat, and some fibres distributed in the urothelium and submucosa expressed immunoreactivity to CGRP. The results obtained suggest that the therapeutic effects of BTX on the urinary bladder might be dependent on changes in the distribution and chemical coding of nerve fibers supplying this organ.

Effects of botulinum toxin type a in the bladder wall of children with neurogenic bladder dysfunction: a comparison of histological features before and after injections

PURPOSE

Botulinum toxin type A has gained popularity in urology. Most reported studies have been in adults at urology centers and most have addressed long-term safety. Since botulinum toxin type A treatment for neurogenic bladder dysfunction requires repeat injections, verifying that such treatment does not induce fibrosis in children seems essential.

MATERIALS AND METHODS

The study was approved by the institutional review board and patients were enrolled after we obtained written consent. Patients with neurogenic bladder dysfunction not responding to conventional treatment (anticholinergics and clean intermittent catheterization) were treated with 10 IU/kg botulinum toxin type A up to a maximum of 300 IU. Endoscopic cold cup biopsies were obtained from the posterolateral bladder wall 1.5 to 2 cm above the ureteral orifice. Bladder wall findings were categorized into 3 groups, including inflammatory infiltration, edema and fibrosis. Each criterion was then graded as mild or severe and analyzed by Fisher's exact test (p <0.05).

RESULTS

A total of 46 bladder wall biopsies were obtained from 40 patients 2 to 18 years old. Biopsies were evaluated in groups 1 and 2, including group 1-20 from patients with no botulinum toxin type A injection and group 2-20 after botulinum toxin type A injection. Group 2 was subdivided into group 3-10 biopsies after 1 injection and group 4-10 after multiple injections. Six patients underwent biopsy twice, that is before the first and second treatments. Histological changes were present in all biopsies. When comparing groups 1 and 2, there was no statistically significant difference in inflammation and edema. However, there was a significant difference in fibrosis between groups 1 and 4 (p <0.05) with apparently decreased fibrosis after multiple injections.

CONCLUSIONS

In our experience repeat botulinum toxin type A injections into the detrusor in children do not lead to increased fibrosis in the bladder wall. This study confirms the long-term safety of botulinum toxin type A in the pediatric population.

Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A

The persisting interest around neurotoxins such as vanilloids and botulinum toxin (BoNT) derives from their marked effect on detrusor overactivity refractory to conventional antimuscarinic treatments. In addition, both are administered by intravesical route. This offers three potential advantages. First, intravesical therapy is an easy way to provide high concentrations of pharmacological agents in the bladder tissue without causing unsuitable levels in other organs. Second, drugs effective on the bladder, but inappropriate for systemic administration, can be safely used as it is the case of vanilloids and BoNT. Third, the effects of one single treatment might be extremely longlasting, contributing to render these therapies highly attractive to patients despite the fact that the reasons to the prolonged effect are still incompletely understood. Attractive as it may be, intravesical pharmacological therapy should still be considered as a second-line treatment in patients refractory to conventional oral antimuscarinic therapy or who do not tolerate its systemic side effects. However, the increasing off-label use of these neurotoxins justifies a reappraisal of their pharmacological properties.