Therapeutic Effect of Botulinum Toxin A on Sensory Bladder Disorders-From Bench to Bedside

Mechanisms of oxidative stress in interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by bladder and/or pelvic pain, increased urinary urgency and frequency and nocturia. The pathophysiology of IC/BPS is poorly understood, and theories include chronic inflammation, autoimmune dysregulation, bacterial cystitis, urothelial dysfunction, deficiency of the glycosaminoglycan (GAG) barrier and urine cytotoxicity. Multiple treatment options exist, including behavioural interventions, oral medications, intravesical instillations and procedures such as hydrodistension; however, many clinical trials fail, and patients experience an unsatisfactory treatment response, likely owing to IC/BPS phenotype heterogeneity and the use of non-targeted interventions. Oxidative stress is implicated in the pathogenesis of IC/BPS as reactive oxygen species impair bladder function via their involvement in multiple molecular mechanisms. Kinase signalling pathways, nociceptive receptors, mast-cell activation, urothelial dysregulation and circadian rhythm disturbance have all been linked to reactive oxygen species and IC/BPS. However, further research is necessary to fully uncover the role of oxidative stress in the pathways driving IC/BPS pathogenesis. The development of new models in which these pathways can be manipulated will aid this research and enable further investigation of promising therapeutic targets.

The Effects of Age, Gender, and Postvoid Residual Volume on Catheterization Rates After Treatment with OnabotulinumtoxinA for Overactive Bladder

Background

Transient increases in postvoid residual urine volume (PVR) requiring clean intermittent catheterization (CIC) have occurred with onabotulinumtoxinA treatment for overactive bladder (OAB).

Objective

To evaluate onabotulinumtoxinA safety and the effect of age, gender, and maximum PVR (PVRmax) on CIC initiation in adults with OAB and urinary incontinence (UI).

Design setting and participants

This was a pooled post hoc analysis of four placebo-controlled, multicenter randomized trials that included adults with idiopathic OAB after first onabotulinumtoxinA treatment (NCT00910845, NCT00910520, NCT01767519, NCT01945489). Patients had at least three urgency UI episodes over 3 d and at least eight micturitions per day, had inadequate management with at least one anticholinergic agent, and were willing to use CIC.

Outcome measurements and statistical analysis

We measured the following outcomes: PVRmax within 12 wk after first treatment; CIC incidence; estimated functional capacity; PVR ratio (PVR/estimated functional capacity).

Results and limitations

Of 1504 patients, 87.7% were women and 88.8% were White. The mean age was 60.5 yr across 10-yr age groups, baseline PVR was 13.8-35.0 ml, and estimated functional capacity was 293.5-475.7 ml. Mean baseline PVR was 21.3 ml overall versus 34.0 ml in the group that started CIC. The CIC incidence was 6.2% for women (range 1.1-8.4%) and 10.5% for men (range 0-14.6%). Higher CIC rates were observed for PVRmax >350 ml (women 91.9%, men 84.6%) in comparison to PVRmax of 201-350 ml (women 32.5%, men 17.4%) and PVRmax <200 ml (women 1.2%, men 1.6%). Overall, 2/1504 patients (both women) were unable to void spontaneously. The mean PVR ratio was highest at week 2. Some subgroups had small sample sizes.

Conclusions

CIC incidence was low overall, was less frequent for women, was rare with PVRmax ≤200 ml, and did not appear to correlate with baseline PVR.

Patient summary

After onabotulinumtoxinA treatment for OAB, patients sometimes insert a catheter to help in emptying their bladder after urinating. In this study, few patients needed a catheter, especially when less urine volume remained after urination.

Current optimal pharmacologic therapies for overactive bladder

INTRODUCTION

Overactive bladder (OAB) is a common syndrome in adults. Current pharmacologic treatment includes antimuscarinic agents and β-3 adrenoceptor agonists. For non-responders to oral medication, intravesical injection of botulinum toxin A (BoNT-A) is an effective option. However, these treatments have potential adverse events and should be cautiously selected for appropriate patients. This review presents the recently published results of clinical trials and studies for patients with OAB and the underlying pathophysiology of OAB. Appropriate medical therapy based on pathophysiology of OAB is also presented.

AREAS COVERED

Literature search from Pubmed from 2001 to 2023 including clinical background, pharmacology, and clinical studies for OAB medications.

EXPERT OPINION

Treatment of OAB syndrome with any antimuscarinic or β-3 adrenoceptor agonist is feasible as a first-line approach. For patients with suboptimal therapeutic effect to full-dose antimuscarinics or mirabegron, combination with both drugs can improve efficacy. Intravesical BoNT-A 100-U injection provides therapeutic effects for refractory OAB. Patients who are refractory to initial pharmacotherapies should be investigated for the underlying pathophysiology; then an appropriate medication can be added, such as an α1-blocker or anti-inflammatory agents. Patient education about behavioral modification and therapies should always be provided with oral medication or BoNT-A injection for OAB patients.

Treatment Outcomes of Intravesical Botulinum Toxin A Injections on Patients with Interstitial Cystitis/Bladder Pain Syndrome

Botulinum toxin A (BoNT-A) is effective in reducing bladder hypersensitivity and increasing capacity through the effects of anti-inflammation in the bladder urothelium; however, studies on the treatment outcome of interstitial cystitis/bladder pain syndrome (IC/BPS) are lacking. We investigated the treatment outcome in IC/BPS patients receiving intravesical BoNT-A injections. This retrospective study included IC/BPS patients who had 100U BoNT-A intravesical injections in the past 20 years. The treatment outcomes at 6 months following the BoNT-A treatment were evaluated using the global response assessment (GRA) scale. The treatment outcomes according to the GRA scale include clinical symptoms, urodynamic parameters, cystoscopic characteristics, and urinary biomarkers, and it was these predictive factors for achieving satisfactory outcomes which were investigated. Among the 220 enrolled patients (180 women, 40 men) receiving BoNT-A injections, only 87 (40%) had significantly satisfactory treatment outcomes. The satisfactory group showed significantly larger voided volumes, and lower levels of both the urinary inflammatory protein MCP-1 and the oxidative stress biomarker 8-isoprostane in comparison to the unsatisfactory group. The IC severity and detrusor pressure are predictive factors of BoNT-A treatment outcomes. IC/BPS patients with less bladder inflammation showed satisfactory outcomes with intravesical BoNT-A injections. Patients with severe bladder inflammation might require more intravesical BoNT-A injections to achieve a satisfactory outcome.

Clinical Application of Botulinum Neurotoxin in Lower-Urinary-Tract Diseases and Dysfunctions: Where Are We Now and What More Can We Do?

Botulinum toxin A (Botox) had been considered a promising drug that has an effect on functional disorders of the lower urinary tract. Because Botox exhibits anti-inflammatory and antispasmodic effects, Botox injection into the bladder can decrease detrusor contractility, reduce bladder hypersensitivity, and eliminate painful sensations. Injecting Botox into the bladder outlet can relax the hyperactivity of the bladder neck, and of the urethral smooth and striated muscles. Based on these therapeutic effects, Botox has been widely applied to treat lower-urinary-tract dysfunctions (LUTDs) such as overactive bladder and neurogenic detrusor overactivity. However, this treatment has not been licensed for use in other LUTDs such as interstitial cystitis, voiding dysfunction due to benign prostatic hyperplasia in men, and dysfunctional voiding in women. Botox has also not been approved for the treatment of children with overactive bladder and dysfunctional voiding; in patients with spinal cord injuries with detrusor sphincter dyssynergia and autonomic dysreflexia; or for poorly relaxed external sphincter in non-neurogenic patients. This article reviews the current knowledge regarding Botox treatment for LUTDs and discusses the potential clinical applications of Botox, as well as work that can be conducted in the future.

Improved symptoms and signs of refractory interstitial cystitis in women after intravesical Nanofat plus platelet-rich plasma grafting: A pilot study

Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by bladder pain accompanied by irritative urinary symptoms, and typical cystoscopic and histological features. In this pilot study, we assessed the impact of lesion-targeted bladder injection therapy using a biocellular regenerative medicine on patients with refractory IC/BPS. The medicine, which was an autologous emulsified fat (Nanofat) and platelet-rich plasma (PRP) combination, was prepared intraoperatively. Six patients (aged 40-54 years), who completed a standard protocol of four consecutive treatments at 3-month intervals, were followed up at 6 months postoperatively. All patients (100%) reported marked (+3; +3 ~ -3) improvement of their overall bladder conditions. Mean bladder pain (from 8.2 to 1.7; range: 0 ~ 10), IC-related symptoms (from 18.5 to 5.7; range: 0 ~ 20), and bother (from 14.8 to 3.8; range: 0 ~ 16) improved significantly (p < 0.01). The normalization of bladder mucosal morphology with treatments was remarkable under cystoscopic examination, and no significant adverse events were found. The cultured mesenchymal stem cells from Nanofat samples of the six patients were verified in vitro. Our preliminary results suggest novel intravesical therapy with autologous Nanofat plus PRP grafting is safe and effective for refractory IC/BPS. Surgical efficacy might be attributed to an in vivo tissue engineering process.

Bladder Hyperactivity Induced by Oxidative Stress and Bladder Ischemia: A Review of Treatment Strategies with Antioxidants

Overactive bladder (OAB) syndrome, including frequency, urgency, nocturia and urgency incontinence, has a significantly negative impact on the quality-of-life scale (QoL) and can cause sufferer withdrawal from social activities. The occurrence of OAB can result from an imbalance between the production of pro-oxidants, such as free radicals and reactive species, and their elimination through protective mechanisms of antioxidant-induced oxidative stress. Several animal models, such as bladder ischemia/reperfusion (I/R), partial bladder outlet obstruction (PBOO) and ovarian hormone deficiency (OHD), have suggested that cyclic I/R during the micturition cycle induces oxidative stress, leading to bladder denervation, bladder afferent pathway sensitization and overexpression of bladder-damaging molecules, and finally resulting in bladder hyperactivity. Based on the results of previous animal experiments, the present review specifically focuses on four issues: (1) oxidative stress and antioxidant defense system; (2) oxidative stress in OAB and biomarkers of OAB; (3) OAB animal model; (4) potential nature/plant antioxidant treatment strategies for urinary dysfunction with OAB. Moreover, we organized the relationships between urinary dysfunction and oxidative stress biomarkers in urine, blood and bladder tissue. Reviewed information also revealed the summary of research findings for the effects of various antioxidants for treatment strategies for OAB.

Management of Urgency and Mixed Urinary Incontinence

Urinary incontinence (UI) is a prevalent disorder that significantly affects quality of life. This article reviews management of urgency and mixed UI by breaking the management algorithm down into observation, lifestyle and behavioral changes, pharmacologic therapy, and procedural management. Stress UI is best managed with mid-urethral slings and is covered in other chapters. Behavioral and pharmacologic management are equally efficacious for urgency UI, but procedural therapy is superior. Mixed UI is conventionally treated by first managing whichever UI subtype is most bothersome. The management of overflow UI is directed at its underlying etiology: detrusor underactivity or bladder outlet obstruction.