Using Botulinum Toxin A for Treatment of Interstitial Cystitis/Bladder Pain Syndrome-Possible Pathomechanisms and Practical Issues

Intravesical Injection of Abobotulinumtoxin-A in Patients with Bladder Pain Syndrome/Interstitial Cystitis

OBJECTIVE

This study aimed to evaluate retrospectively the outcomes of Abobotulinumtoxin-A (Dysport®) intravesical injection in refractory interstitial cystitis/ bladder pain syndrome patients to first- and second-line treatment.

MATERIALS AND METHODS

From March 2016 to 2021, 44 adult patients with bladder pain syndrome who were refractory to first- and second-line treatment were enrolled in our study. The Bladder Pain/Interstitial Cystitis Symptom Score questionnaire was filled out for every patient before and 1-3 months after intervention in addition to urodynamic evaluation. Patient satisfaction was evaluated using a scoring system that was defined as high or >80% improvement (highly satisfied), intermediate 40%-79% (intermediate satisfaction), and poor 0%-39% improvement.

RESULTS

The mean age of our study population was 57 years, including 41 females and 3 males. The mean follow-up time was 9 months. According to the results of urodynamics, 68% of cases had low capacity, and detrusor overactivity, while 18% had only low capacity. In terms of the endpoint outcome, half of the patients (52%) had intermediate satisfaction, whereas 41% reported a good response. Only 3 cases had no response or felt (7%) any improvement after the intervention (poor response). The paired t-test analysis revealed that the mean Bladder Pain/Interstitial Cystitis Symptom Score was reduced after injection (P = .001).

CONCLUSION

Our results showed the efficacy and safety of intravesical injections with Abobotulinumtoxin-A (Dysport®) in patients with interstitial cystitis/bladder pain syndrome. Further randomized controlled trials are recommended to investigate its superiority over placebo considering the need for anesthesia, the occurrence of local complications, risks of urinary retention, and a large post-void residual (PVR) volume.

Botulinum Toxin A Injection for Autonomic Dysreflexia-Detrusor Injection or Urethral Sphincter Injection?

Spinal cord injuries (SCI) have a profound impact on autonomic systems, sometimes resulting in multi-organ dysfunction, including of the neurogenic bladder. Autonomic dysreflexia (AD) is commonly seen in patients with SCI above T6 when the injured cord develops a deregulated sympathetic reflex, which can be induced by bladder sensation and can cause hypertensive crisis. While intravesical injection of botulinum toxin A (Botox) is a standard therapy for neurogenic detrusor overactivity, the role of Botox for AD has rarely been described. This study reviewed the medical records of SCI patients who reported AD and received either detrusor or urethral sphincter injection with Botox. The primary endpoint is the subjective improvement of AD. The secondary endpoint is a change in videourodynamic parameters before and after Botox injection. A total of 200 patients were enrolled for analysis. There were 125 (62.5%) patients in the detrusor injection group, and 75 (37.5%) in the urethral sphincter injection group. There were 79 (63.2%) patients in the detrusor injection group and 43 (57.3%) in the urethral sphincter injection group reporting moderate or marked improvement. Detrusor injection leads to a greater improvement in AD, probably because of decreased detrusor pressure and increased compliance after Botox injection. Urethral sphincter injection appears to have a modest effect on AD, despite general improvements in the voiding parameters of videourodynamic study.

Preliminary Exploration of a New Therapy for Interstitial Cystitis/Bladder Pain Syndrome: Botulinum Toxin A Combined with Sapylin

Interstitial cystitis/bladder pain syndrome (IC/BPS) is an intractable disease without long-term effective therapy. This study aims to evaluate the efficacy and safety of botulinum toxin A (BoNT/A) plus Sapylin, which might modulate the immune response of the bladder in the treatment of IC/BPS patients. We retrospectively investigated the clinical outcomes among 34 patients who accepted repeated Sapylin instillations after 200 U of BoNT/A submucosally injected into bladder walls (Mix group) and 28 patients who received BoNT/A alone (Control group). Each of the bladder walls (left, right, anterior and posterior) was injected six times with 8 U of BoNT/A per injection. The primary outcome measure was the global response assessment. The results showed that at 6 months post-injection, the response rate in the Mix group was remarkably higher than that in the Control group (58.8% vs. 28.6%, p < 0.05). The mean effective duration of the responders in the Mix group was apparently better than that in the Control group (27.5 (range 0-89) vs. 4.9 (range 0-11) months, p < 0.05). None of the patients experienced serious adverse events. In conclusion, repeated intravesical instillations of Sapylin after BoNT/A injection can produce significantly better clinical outcomes than BoNT/A alone in IC/PBS patients.

Effect of Intratrigonal Botulinum Toxin in Patients with Bladder Pain Syndrome/Interstitial Cystitis: A Long-Term, Single-Center Study in Real-Life Conditions

The high percentage of treatment failures seen in patients with bladder pain syndrome/interstitial cystitis (BPS/IC) managed conservatively frequently demands invasive treatment options. We aimed to evaluate the long-term efficacy and adverse events of intratrigonal botulinum toxin injection in such circumstances, as well as to determine possible predictors of response to toxin treatment. A retrospective cohort study included 47 female BPS/IC patients treated with onabotulinum toxin A (OnabotA) in a tertiary hospital between the years 2009 and 2022. All patients received 100 U of OnabotA in ten injections limited to the trigonal area. Patients were divided into three groups based on their treatment response as responders, non-responders and lost to follow-up due to non-medical reasons. The clinical and surgical records of the individuals were retrieved, including the 10-point visual analogue scale (VAS), the number of treatments, the time between injections, and the age at the first injection. A total of 25 patients (>50% of the cohort) were long-term responders, but none of the evaluated parameters was a predictor for this circumstance: age, pain intensity, or duration of improvement following the injection. The time between injections was stable (around 1 year). No severe adverse events were registered. The intratrigonal injection of botulinum toxin in patients with BPS/IC was an effective and safe long-term treatment for patients' refractory to conservative forms of treatment. Age, basal pain intensity, and time to injection request did not predict long-term response to OnaBotA.

Low-Energy Shock Wave Plus Intravesical Instillation of Botulinum Toxin A for Interstitial Cystitis/Bladder Pain Syndrome: Pathophysiology and Preliminary Result of a Novel Minimally Invasive Treatment

Low-energy shock wave (LESW) therapy is known to facilitate tissue regeneration with analgesic and anti-inflammatory effects. LESW treatment has been demonstrated to be effective in treating chronic prostatitis and pelvic pain syndrome as well as overactive bladder, and it has a potential effect on interstitial cystitis/bladder pain syndrome (IC/BPS) in humans. LESW reduces pain behavior, downregulates nerve growth factor expression, and suppresses bladder overactivity by decreasing the expression of inflammatory proteins. Previous rat IC models have shown that LESW can increase urothelial permeability, facilitate intravesical delivery of botulinum toxin A (BoNT-A), and block acetic acid-induced hyperactive bladder, suggesting that LESW might be a potential therapeutic module for relieving bladder inflammatory conditions, such as bladder oversensitivity, IC/BPS, and overactive bladder. A recent clinical trial showed that LESW monotherapy was associated with a significant reduction in pain scores and IC symptoms. BoNT-A detrusor injection or liposome-encapsulated BoNT-A instillation could also inhibit inflammation and improve IC symptoms. However, BoNT-A injection requires anesthesia and certain complications might occur. Our preliminary study using LESW plus intravesical BoNT-A instillation every week demonstrated an improvement in global response assessment without any adverse events. Moreover, an immunohistochemistry study revealed the presence of cleaved SNAP25 protein in the suburothelium of IC bladder tissue, indicating that BoNT-A could penetrate across the urothelial barrier after application of LESW. These results provide evidence for the efficacy and safety of this novel IC/BPS treatment by LESW plus BoNT-A instillation, without anesthesia, and no bladder injection. This article reviews the current evidence on LESW and LESW plus intravesical therapeutic agents on bladder disorders and the pathophysiology and pharmacological mechanism of this novel, minimally invasive treatment model for IC/BPS.

An indirect comparison meta-analysis of noninvasive intravesical instillation and intravesical injection of botulinum toxin-A in bladder disorders

BACKGROUND

Botulinum toxin type A (BTX-A) intravesical instillation and BTX-A intravesical injection are both effective treatments or overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS), but direct comparative studies of the two treatments are lacking.

METHODS

We conducted a pairs-comparison meta-analysis and an adjusted indirect comparison meta-analysis extracting published data from randomized controlled trials in literature databases from the inception of each database to Aug. 31, 2021, evaluating efficacy and safety of BTX-A intravesical instillation and BTX-A intravesical injection. We also carried out a subgroup analysis.

RESULTS

We identified 24 trials in 21 studies were included in our study, of which 18 trials in 17 studies were BTX-A intravesical injections, 6 trials in 4 studies were BTX-A intravesical instillation. Compared with the normal saline injection, BTX-A intravesical injections for patients with OAB and IC/ BPS can obviously improve the symptoms of urinary frequency, urgency episode, UI and UUI, but BTX-A significantly increased the rate of urinary retention and urinary tract infection and increased PVR (p < 0.05). Adjusted indirect comparison meta-analysis showed that BTX-A intravesical injections was more effective than BTX-A intravesical instillation (p > 0.05). Surprisingly, BTX-A intravesical instillation had fewer side effects than BTX-A intravesical injections (p < 0.05).

CONCLUSIONS

Although BTX-A intravesical injections of OAB and IC/BPS has been significantly superior the BTX-A intravesical instillation, it has major side effects, but this needs to be confirmed by more large-scale, multicenter, direct comparison randomized controlled trials.

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.