Botulinum toxin for the lower urinary tract

Ultrasound-assisted intravesical botulinum toxin A delivery attenuates acetic acid-induced bladder hyperactivity in rats

Background: Intradetrusor injection of botulinum toxin A (BTX-A) is an effective treatment for overactive bladder (OAB). However, the occurrence of adverse events associated with BTX-A injection therapy hinders its acceptance among patients and its clinical promotion. Intravesical instillation of BTX-A offers a promising alternative to injection therapy for treating OAB. Nevertheless, due to the presence of the bladder permeability barrier (BPB) and the high molecular weight of BTX-A, direct instillation is unable to penetrate the bladder urothelium. Purpose: This study aims to investigate the safety and feasibility of ultrasound-assisted intravesical delivery of BTX-A and its potential benefits in a rat model of bladder hyperactivity induced by acetic acid instillation. Methods: Hengli BTX-A and microbubbles (MB) were mixed and prepared as a novel complex. The size distribution and zeta potentials of the complex were measured. On day 1, rats' bladders were instilled with 1 mL of saline, BTX-A (20 U in 1 mL), MB, or MB-BTX-A (20 U in 1 mL) complex with or without ultrasound (US) exposure (1 MHz, 1.5 W/cm2, 50% duty cycle, sonication for 10 s with a 10-s pause for a total of 10 min). The instillations were maintained for 30 min. After 7 days, cystometry was performed by filling the bladder with saline and 0.3% acetic acid (AA). Bladders were collected, weighed, and processed for immunoblotting, enzyme-linked immunosorbent assay (ELISA), histologic, and immunofluorescence analyses. Expression and distribution of SNAP-25 and SNAP-23 were assessed using Western blot and immunofluorescence. Calcitonin gene-related peptide (CGRP) in the bladder was detected using ELISA. Results: Intercontraction intervals (ICI) decreased by 72.99%, 76.16%, and 73.96% in rats pretreated with saline, BTX-A, and US + MB, respectively. However, rats treated with US + MB + BTX-A showed a significantly reduced response to AA instillation (57.31% decrease in ICI) without affecting amplitude, baseline pressure, or threshold pressure. Rats treated with US + MB + BTX-A exhibited increased cleavage of SNAP-25 and CGRP expression compared to the control group. Conclusion: Ultrasound-assisted intravesical delivery of BTX-A, with the assistance of MB cavitation, led to cleavage of SNAP-25, inhibition of calcitonin gene-related peptide release from afferent nerve terminals, and amelioration of acetic acid-induced bladder hyperactivity. These results support ultrasound-assisted intravesical delivery as an efficient non-injection method for administering BTX-A.

Promise and the Pharmacological Mechanism of Botulinum Toxin A in Chronic Prostatitis Syndrome

Chronic prostatitis/chronic pelvic pain syndrome (CP/ CPPS) has a negative impact on the quality of life, and its etiology still remains unknown. Although many treatment protocols have been evaluated in CP/CPPS, the outcomes have usually been disappointing. Botulinum neurotoxin A (BoNT-A), produced from Clostridium botulinum, has been widely used to lower urinary tract dysfunctions such as detrusor sphincter dyssynergia, refractory overactive bladder, interstitial cystitis/bladder pain syndromes, benign prostatic hyperplasia, and CP/ CPPS in urology. Here, we review the published evidence from animal models to clinical studies for inferring the mechanism of action underlying the therapeutic efficacy of BoNT in CP/CPPS. Animal studies demonstrated that BoNT-A, a potent inhibitor of neuroexocytosis, impacts the release of sensory neurotransmitters and inflammatory mediators. This pharmacological action of BoNT-A showed promise of relieving the pain of CP/CPPS in placebo-controlled and open-label BoNT-A and has the potential to serve as an adjunct treatment for achieving better treatment outcomes in CP/CPPS patients.

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.

The efficacy of botulinum toxin A and sacral neuromodulation in the management of interstitial cystitis (IC)/bladder pain syndrome (BPS), what do we know? ICI-RS 2017 think thank, Bristol

AIMS

This manuscript aims to address the evidence availale in the literature on the efficacy of Botulinum Toxin A (BoNT-A) and sacral neuromodulation (SNM) in patients suffering from Interstitial Cystitis (IC)/BPS and propose further research to identify mechanisms of action and establish the clinical efficacy of either therapy.

METHODS

At the International Consultation on Incontinence-Research Society (ICI-RS) in 2017, a panel of Functional Urologists and Urogynaecologists participated in a Think Tank (TT) discussing the management of IC/BPS by BoNT-A and SNM, using available data from both PubMed and Medicine literature searches.

RESULTS

The role of BoNT-A and SNM in the treatment of IC/BPS are discussed and mechanisms of actions are proposed. Despite the available randomized trial data on the effect of intravesical BoNT-A treatment on symptoms of IC/BPS, a consistent conclusion of a positive effect cannot be drawn at the moment, as the published studies are small and heterogeneous in design. There is substantive evidence for the positive effects of SNM on symptoms of IC/BPS patients however, during patient selection, it is important to distinguish the degree and the location of pain in order to tailor the best therapy to the right patients.

CONCLUSIONS

Both intravesical BoNT-A treatment and SNM have been shown to have positive effects in patients with IC/BPS. However, firm conclusions cannot yet be drawn. Patient-reported outcomes and quality of life should be assessed in addition to urinary and pain symptoms. Since current treatments mainly focus on symptomatic relief, future research should also focus on clarifying the pathogenic mechanisms involved in IC/BPS.

A Prospective, Multicenter, Double-Blind, Randomized Trial of Bladder Instillation of Liposome Formulation OnabotulinumtoxinA for Interstitial Cystitis/Bladder Pain Syndrome

PURPOSE

Intravesical instillation of liposomal formulated botulinum toxin A (lipotoxin) has shown therapeutic effects as treatment of refractory overactive bladder without needle injections. We assessed lipotoxin to treat refractory interstitial cystitis/bladder pain syndrome.

MATERIALS AND METHODS

This 2-center, double-blind, randomized, placebo controlled, physician initiated study enrolled patients with refractory interstitial cystitis/bladder pain syndrome. A total of 31 patients were assigned to intravesical instillation of lipotoxin (onabotulinumtoxinA 200 U with 80 mg sphingomyelin), 28 were assigned to onabotulinumtoxinA 200 U in normal saline and 31 were assigned to normal saline alone. The primary end point was the average change in O'Leary-Sant symptom scores, including ICSI (Interstitial Cystitis Symptom Index) and ICPI (Interstitial Cystitis Problem Index) between baseline and 4 weeks after treatment. Other end points included the average changes in a 3-day voiding diary, a visual analog scale for pain and a global response assessment of patient satisfaction.

RESULTS

Improvements in the pain scale and O'Leary-Sant symptom scores occurred in all 3 groups by 4 weeks after treatment. Lipotoxin instillation was associated with a statistically significant decrease in O'Leary-Sant symptom scores (mean ± SD 7.38 ± 8.75), ICSI (4.00 ± 4.28), ICPI (3.35 ± 5.11) and the visual analog scale pain scale (1.64 ± 2.52), and an increase in the global response assessment (1.35 ± 1.28). However, there was no difference in improvement among the 3 groups. No significant adverse events were found in any group.

CONCLUSIONS

Lipotoxin failed to demonstrate a positive proof of concept compared to onabotulinumtoxinA or placebo. However, a single intravesical instillation of lipotoxin was associated with decreased interstitial cystitis/bladder pain syndrome symptoms compared to baseline in patients with moderate to severe interstitial cystitis/bladder pain syndrome. The effect was likely due to a significant placebo effect.

Efficacy of botulinum toxin type A 100 Units versus 200 units for treatment of refractory idiopathic overactive bladder

Objective:

To evaluate the efficacy and safety of a single intra detrusor injection of BoNTA comparing two different doses (100 U or 200 U) in patients with idiopathic overactive bladder.

Materials and Methods:

A randomized prospective study evaluated the efficacy of BoNTA in management of refractory idiopathic overactive bladder and included 80 patients. All patients were assessed initially by taking a history, a physical examination, overactive bladder symptom score, urine analysis, routine laboratory investigations, KUB and pelviabdominal. OABSS was adjusted on all patients postoperative at 1,3,6,9 months also Urodynamic was done for all patients preoperative and postoperative at 3, 6, 9 months.

Results:

The mean age was 30.22±8.37 and 31.35±7.61 in group I and II respectively. There was no statistically difference between both groups in all parameters all over the study except at 9 months after treatment. Hematuria was observed 6 and 9 patients in group I and II respectively. Dysuria was observed in 6 and 15 patients in group I and II respectively. UTI was detected in 3 and 7 patients in group I and II respectively.

Conclusion:

A single-injection procedure of 100 U or 200 U BoNTA is an effective and safe treatment for patients with IOAB who failed anticholinergic regimens. OABSS and QoL were improved for 6 months; 100 U injections seemed to have comparable results with 200 U. There was a significant difference at month 9 towards 200 U with more incidences of adverse events.

Efficacy and safety of botulinum toxin injection for interstitial cystitis/bladder pain syndrome: a systematic review and meta-analysis

PURPOSE

To investigate the overall treatment efficacy and safety of botulinum toxin type A (BoNTA) injections compared with placebo in interstitial cystitis/bladder pain syndrome (IC/BPS).

METHODS

We conducted a systematic review and meta-analysis of the published literature in PubMed, Cochrane Library, and EMBASE on BoNTA use in IC/BPS. Outcome measures included changes of OLS, ICSI, ICPI, VAS, frequency, nocturia, FBC, Qmax, and PVR from baseline and also included adverse events.

RESULTS

A total of five studies were included, with a total sample size of 252 subjects (133 subjects in the experimental group and 119 subjects in the control group). The duration of follow-up ranged from 8 to 12 weeks. The BoNTA dosage was from 50 to 200 U. The pooled overall SMD in the mean change of VAS for the BoNTA group versus the placebo group was -0.49 (95 % CI -0.74, -0.23). There were also significant improvements in ICPI and frequency. The other outcomes (ICSI, nocturia, Qmax, and FBC) were not statistically different between the two groups.

CONCLUSION

Although BoNTA is not regulatory approved indication, this first evidence-based systematic review and meta-analysis of BoNTA injection for IC/BPS showed significant differences in efficacy of treatment compared with placebo, especially for pain control, and also showed no differences in the rate of procedure-related adverse events.

Investigational drugs for bladder pain syndrome (BPS) / interstitial cystitis (IC)

INTRODUCTION

Bladder pain syndrome (BPS)/interstitial cystitis (IC) is associated with sensory lower urinary tract symptoms. Unfortunately, many of the existing oral treatments are ineffective in most patients of BPS/IC, which is the motivation for developing new drugs and therapeutic approaches. This review covers the latest drugs that have been investigated in BPS/IC patients. Intravesical treatments offer the opportunity to directly target the painful bladder with less systemic side effects.

AREAS COVERED

In this review, the authors analyze the existing literature supporting the treatment of BPS/IC with conventional drugs including heparin, hyaluronic acid, chondroitin sulfate, and dimethylsulfoxide (DMSO). Furthermore, investigational drugs such as tanezumab and adalimumab, capable of sequestering nerve growth factor (NGF), and Tumor necrosis factor-α (TNF- α) are discussed. Investigational treatments such as liposomes, botulinum toxin (BTX), liposomal BTX, PD-0299685 (a Ca(2+) channel ɑ2δ ligand), continuous intravesical lidocaine, and AQX-1125 (a novel SHIP1 activating compound) are also covered.

EXPERT OPINION

New investigational drugs offer promising improvements in clinical outcomes for BPS/IC patients; however, BPS/IC is a chronic pain disorder that is very vulnerable to a strong placebo effect. In addition, BPS/IC is a heterogeneous disorder that can be classified into several phenotypes. Since different phenotypes of BPS/IC respond differently to systemic and intravesical treatments, the authors believe that new drugs developed for BPS/IC are more likely to meet their predetermined clinical endpoints if the inclusion/exclusion criterion is tailored to specific phenotype of BPS/IC patients.

Potential Effect of Liposomes and Liposome-Encapsulated Botulinum Toxin and Tacrolimus in the Treatment of Bladder Dysfunction

Bladder drug delivery via catheter instillation is a widely used treatment for recurrence of superficial bladder cancer. Intravesical instillation of liposomal botulinum toxin has recently shown promise in the treatment of overactive bladder and interstitial cystitis/bladder pain syndrome, and studies of liposomal tacrolimus instillations show promise in the treatment of hemorrhagic cystitis. Liposomes are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core that can encapsulate hydrophilic and hydrophobic drug molecules to be delivered to cells via endocytosis. This review will present new developments on instillations of liposomes and liposome-encapsulated drugs into the urinary bladder for treating lower urinary tract dysfunction.

Intravesical liposome drug delivery and IC/BPS

Intravesical therapy has previously shown to be effective in delaying or preventing recurrence of superficial bladder cancer. This local route of drug administration is now demonstrating promise in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) with the benefit of minimal systemic side effects. Liposomes (LPs) are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core. They can incorporate drug molecules, both hydrophobic and hydrophilic, and vastly improve cellular uptake of these drug molecules via endocytosis. Intravesical LPs have therapeutic effects on IC/BPS patients, mainly due to their ability to form a protective lipid film on the urothelial surface and repair the damaged urothelium. This review considers the current status of intravesical LPs and LP mediated drug delivery for the treatment of IC/BPS.

Bladder instillation of liposome encapsulated onabotulinumtoxina improves overactive bladder symptoms: a prospective, multicenter, double-blind, randomized trial

PURPOSE

Cystoscopic intradetrusor injection of botulinum toxin has helped patients with refractory overactive bladder but with the increased risks of urinary tract infection and urinary retention. We assessed whether catheter instillation of 200 U onabotulinumtoxinA formulated with liposomes is safe and effective for the treatment of overactive bladder.

MATERIALS AND METHODS

This 2-center, double-blind, randomized, placebo controlled study enrolled patients with overactive bladder inadequately managed with antimuscarinics. Patients were assigned to intravesical instillation of lipo-botulinum toxin (31) or normal saline (31). The primary end point was the mean change in micturition events per 3 days at 4 weeks after treatment. Additional end points included mean changes in urgency events, frequency and urinary urge incontinence, as well as changes in overactive bladder symptom scores and urgency severity scores.

RESULTS

At 4 weeks after treatment lipo-botulinum toxin instillation was associated with a statistically significant decrease in micturition events per 3 days (-4.64 for lipo-botulinum toxin vs -0.19 for placebo, p = 0.0252). Lipo-botulinum toxin instillation was also associated with a statistically significant decrease in urinary urgency events with respect to baseline but not placebo. However, lipo-botulinum toxin instillation was associated with a statistically significant decrease in urgency severity scores compared to placebo (p = 0.0181). These observed benefits of lipo-botulinum toxin instillation were not accompanied by an increased risk of urinary retention. The effects of lipo-botulinum toxin on urinary urge incontinence were inconclusive.

CONCLUSIONS

A single intravesical instillation of lipo-botulinum toxin was associated with decreases in overactive bladder symptoms without side effects. Intravesical instillation of liposomal botulinum toxin may be a promising approach to treat refractory overactive bladder.

Single compartment drug delivery

Drug design is built on the concept that key molecular targets of disease are isolated in the diseased tissue. Systemic drug administration would be sufficient for targeting in such a case. It is, however, common for enzymes or receptors that are integral to disease to be structurally similar or identical to those that play important biological roles in normal tissues of the body. Additionally, systemic administration may not lead to local drug concentrations high enough to yield disease modification because of rapid systemic metabolism or lack of sufficient partitioning into the diseased tissue compartment. This review focuses on drug delivery methods that physically target drugs to individual compartments of the body. Compartments such as the bladder, peritoneum, brain, eye and skin are often sites of disease and can sometimes be viewed as "privileged," since they intrinsically hinder partitioning of systemically administered agents. These compartments have become the focus of a wide array of procedures and devices for direct administration of drugs. We discuss the rationale behind single compartment drug delivery for each of these compartments, and give an overview of examples at different development stages, from the lab bench to phase III clinical trials to clinical practice. We approach single compartment drug delivery from both a translational and a technological perspective.

Intravesical treatment of bladder pain syndrome/interstitial cystitis: from the conventional regimens to the novel botulinum toxin injections

INTRODUCTION

Bladder pain syndrome (BPS) includes interstitial cystitis (IC) and is often used as a synonym of it (i.e., BPS/IC). It is associated with lower urinary tract symptoms as well as with negative cognitive, behavioral, sexual and/or emotional consequences. Unfortunately, none of the numerous existing oral and intravesical treatments have been effective for all of the BPS subtypes and therefore relevant research is ongoing.

AREAS COVERED

In this review, the authors analyze the existing literature for the intravesical treatment of BPS/IC with focus on the novel administration of botulinum toxin (BTX). Several intravesical drugs have been studied in the past, including lidocaine, heparin, pentosan polysulfate sodium, dimethyl sulfoxide, chondroitin sulfate, hyaluronic acid as well as investigational drugs such as GM-0111. Recently, intravesical submucosal injections of BTX have been studied in patients with BPS/IC.

EXPERT OPINION

Most of the recent studies use BTX-A with no serious adverse effects and with satisfactory results in patients who do not respond to oral or standard intravesical therapy. Nevertheless, there is no consensus regarding the best dosage scheme of BTX, the injection sites and the treatment intervals. BTX intravesical administration in patients with BPS/IC is a safe and efficient treatment option; yet the level of evidence of the initial studies is not high. There is still the need for large randomized controlled studies so that a consensus can be reached for the ideal BTX dosage, injection sites and intervals between treatments.

Intravesical botulinum type-A toxin (Dysport®) in the treatment of idiopathic detrusor overactivity in children

OBJECTIVE

Botulinum type-A toxin is increasingly used for refractory idiopathic detrusor overactivity (IDO) in children. We reviewed our experience and sought to ascertain the influence of dose and functional bladder capacity on outcome.

PATIENTS AND METHODS

Thirty patients, aged 6-16 years, with urodynamically proven IDO, had intravesical injections of 400-500 iu of Dysport(®). Outcome was assessed clinically at least 5 months after the injection.

RESULTS

Data were available for 27 patients. Urinary frequency was improved in 10; nocturia was improved in 7. Urgency resolved in 10 patients and urge incontinence in 12 (44%). Complications reported were UTI (7), urinary retention (1) and bladder pain (1). The dose of Dysport(®) used was not significantly higher (14 iu/kg v 13 iu/kg) in patients dry at follow up than in those who remained wet (p = 0.45). Functional bladder capacity was not significantly different in patients dry after treatment (p = 0.82).

CONCLUSION

This retrospective study demonstrates similar response to a single treatment with intravesical Botulinum type-A toxin to previous series. We did not demonstrate a correlation between dose or functional bladder capacity and resolution of incontinence. A multi-centre study is required to further investigate this promising treatment.

OnobotulinumtoxinA Has No Effects on Growth of LNCaP and PC3 Human Prostate Cancer Cells

OBJECTIVES

Intraprostatic injection of botulinum toxin (BTX) has been reported to have therapeutic effects on lower urinary tract symptoms related to benign prostate hyperplasia (BPH). Patients with BPH are at risk of having prostate cancer. The present study was conducted to assess the effect of onobotulinumtoxinA on prostate cancer in vitro and in vivo.

METHODS

Human prostate cancer cell lines, LNCaP and PC3 were exposed to different doses of onobotulinumtoxinA (0-10 U; Allergan, Irvine, CA, USA). Cell viability, DNA fragmentation and apoptosis assay were subsequently measured. For the in vivo study, LNCaP and PC3 xenografts were introduced into nude mice and treated with intra-tumoral onobotulinumtoxinA or saline injection. Tumor volume, histopathology and apoptosis were assessed. Presence of SNAP-25 protein, the molecular target of onobotulinumtoxinA, was studied in both cell lines by Western blot analysis.

RESULTS

OnobotulinumtoxinA did not significantly affect cell proliferation or apoptosis in LNCaP and PC3 cells. There was no significant difference in tumor size and histopathological findings between the experimental and control groups. There was no detectable SNAP-25 protein in both cell lines.

CONCLUSION

OnobotulinumtoxinA does not affect the growth of LNCaP or PC3 cells in vitro and in vivo or produce significant anti-tumor effects. Intraprostatic BTX injection for BPH might not affect the growth of prostate cancer.

Discontinuation rates and inter-injection interval for repeated intravesical botulinum toxin type A injections for detrusor overactivity

OBJECTIVE

To report discontinuation rates, inter-injection interval and complication rates after repeated intravesical botulinum toxin type A for the treatment of detrusor overactivity.

METHOD

Patients with urodyamically proven detrusor overactivity who had two or more botulinum toxin type A injections in the period 2004-2011 at Freeman Hospital, Newcastle Upon Tyne, UK, were considered for the present study. Discontinuation rates, complication rates and interval between botulinum toxin type A treatments were retrospectively analyzed.

RESULTS

Overall, 125 patients (median age 53 years, range 19-83 years) were included in the analysis. The female-to-male ratio was 2.4:1 and median follow up was 38 months. A total of 96 patients had idiopathic detrusor overactivity, whereas 29 had neurogenic detrusor overactivity. A total of 667 injections were carried out, with 125 patients receiving two injections, 60 receiving three injections, 28 receiving four injections, 14 receiving five injections, three receiving six injections, three receiving seven injections and two receiving eight injections. The mean interval (±standard deviation) between the first and second injection (n = 125) was 17.6 months (±10.4), between the second and third (n = 60) was 15.7 ± 7.4 months, between the third and fourth (n = 28) was 15.4 ± 8.6 months, and between the fourth and subsequent injections (n = 22) was 11.6 ± 4.5 months. A total of 26% required intermittent catheterization, and 18% developed recurrent urinary tract infections. There was a discontinuation rate of 25% at 60 months.

CONCLUSION

Repeated botulinum toxin type A injections represent a safe and effective method for managing patients with idiopathic detrusor overactivity and neurogenic detrusor overactivity. We have shown that the inter-injection interval remains unchanged up to five injections.

The Successful and Novel Treatment of Non-Neurogenic Detrusor-External Sphincter Dyssynergia (DESD) with Botulinum Toxin A

Introduction:

Our study aims to examine the treatment outcomes of patients with non-neurogenic detrusor-external sphincter dyssynergia (DESD) after the injection of botulinum toxin A (BTX-A, Botox®) to the external sphincter.

Methods:

A retrospective review of nine patients with DESD was performed. All patients were diagnosed with the aid of video urodynamic studies. Pre-operative evaluation was standardised using bladder diary, urine microscopy and culture, bedside ultrasound of the kidneys and bladder, and renal function test. Each received BTX-A injection of 50–100U to the external sphincter. The pre-operative and post-operative maximum flow rate (Qmax) and post-void residual urine (PVRU) were objectively compared using paired-samples t test.

Results:

All the injections were performed from December 2006 to March 2008. Of the nine patients, seven (77.8%) were female and two (22.2%) were male. The mean age was 49.2 years (range 20–64 years). The mean pre-operative maximum flow rate (Qmax) was 9.7±6.26 ml/s. A month later, the post-operative Qmax improved to 16.5±11.3 ml/s. Mean difference in Qmax was 6.76±8.1 ml/s ( P = 0.037). The mean preoperative post void residual urine (PVRU) was 179.2±86.8 ml. This improved to 45.7±44.4 ml post-operatively. The mean difference in PVRU of 133.6±77.2 ml ( P = 0.001).

Conclusion:

In patients with DESD, there is a significant improvement in PVRU and Qmax after the injection of BTX-A. Hence, BTX-A injection is an effective method of treatment for DESD. However, further studies and follow-up are required to further evaluate patient satisfaction, quality of life and need for repeated injections.

Expression of apoptosis-regulating genes in the rat prostate following botulinum toxin type A injection

Background

Onabotulinumtoxin A (OnabotA) injection has been investigated as a novel treatment for benign prostatic enlargement caused by benign prostatic hyperplasia. An OnabotA - induced volume reduction caused by sympathetic fibers impairment has been proposed as a potential mechanism of action. Our aim was to investigate the expression of apoptosis-regulating proteins in the rat prostate following OnabotA intraprostatic injection.

Methods

Adult Wistar rats were injected in the ventral lobes of the prostate with 10 U of OnabotA or saline. A set of OnabotA-injected animals was further treated with 0.5 mg/kg of phenylephrine (PHE) subcutaneously daily. All animals were sacrificed after 1 week and had their prostates harvested. Immunohistochemical staining was performed for Bax, Bcl-xL and caspase-3 proteins and visualized by the avidin-biotin method. The optical density of the glandular cells was also determined, with measurement of differences between average optical densities for each group.

Results

Saline-treated animals showed intense epithelial staining for Bcl-xL and a faint labelling for both Bax and Caspase-3. OnabotA-treated rats showed a reduced epithelial staining of Bcl-xL and a consistently increased Bax and Caspase-3 staining when compared with saline-treated animals. PHE-treated animals showed a stronger Bcl-xL staining and reduced staining of both Bax and Caspase-3 when compared to the OnabotA group. Mean signal intensity measurements for each immunoreaction confirmed a significant decrease of the signal intensity for Bcl-xL and a significant increase of the signal intensity for Bax and Caspase 3 in OnabotA-injected animals when compared with the control group. In OnabotA+PHE treated animals mean signal intensity for Bcl-xL, Bax and Caspase 3 immunoreactions was identical to that of the control animals.

Conclusions

These results support the hypothesis that OnabotA activates apoptotic pathways in the rat prostate through a mechanism that involves sympathetic outflow impairment.