Intraprostatic injection of botulinum toxin type-A relieves bladder outlet obstruction in human and induces prostate apoptosis in dogs

[Botulinum toxin in male lower urinary tract symptoms (LUTS): What can we expect?]

During the last two decades botulinum toxin has also conquered urology. Botulinum toxin reduces the contractility and sensitivity of the detrusor muscle and relieves pain. It is therefore a promising drug whose use in men also appears promising. The following article highlights the practical relevance of botulinum toxin for male lower urinary tract symptoms (LUTS). But first of all, a distinction must be made between use in male LUTS due to benign prostate syndrome (BPS) and use in cases of overactive bladder (OAB) alone. A differentiated diagnosis and treatment of male LUTS is therefore essential.

Therapeutic Applications of Botulinum Neurotoxins in Veterinary Medicine

Botulinum neurotoxins (BoNTs) are emerging as multipurpose therapeutic compounds for the treatment of several different syndromes involving peripheral and central nervous systems, and muscular and musculoskeletal disorders both in human and veterinary medicine. Therefore, the study of BoNTs is rapidly developing and identifying newly produced BoNT variants. Efforts should be made to clarify the biological and pharmacological characteristics of these novel BoNTs as well as the natural ones. The high potential of BoNTs as a therapeutic compound for medical syndromes lies in its ability to reach a specific cell type while bypassing other cells, thus having mild or no side effects. In this paper the recent developments in BoNTs are reviewed with the aim of analyzing the current knowledge on BoNTs' biological mechanisms of action, immunogenicity, formulations, and therapeutic applications in the veterinary field, highlighting advantages and drawbacks and identifying the gaps to be filled in order to address research priorities.

Can Botulinum Toxin A Still Have a Role in Treatment of Lower Urinary Tract Symptoms/Benign Prostatic Hyperplasia Through Inhibition of Chronic Prostatic Inflammation?

Patients with benign prostatic hyperplasia (BPH) can exhibit various lower urinary tract symptoms (LUTS) owing to bladder outlet obstruction (BOO), prostatic inflammation, and bladder response to BOO. The pathogenesis of BPH involves an imbalance of internal hormones and chronic prostatic inflammation, possibly triggered by prostatic infection, autoimmune responses, neurogenic inflammation, oxidative stress, and autonomic dysfunction. Botulinum toxin A (BoNT-A) is well recognized for its ability to block acetylcholine release at the neuromuscular junction by cleaving synaptosomal-associated proteins. Although current large clinical trials have shown no clinical benefits of BoNT-A for the management of LUTS due to BPH, BoNT-A has demonstrated beneficial effects in certain subsets of BPH patients with LUTS, especially in males with concomitant chronic prostatitis/chronic pelvic pain syndrome and smaller prostate. We conducted a review of published literature in Pubmed, using Botulinum toxin, BPH, BOO, inflammation, LUTS, and prostatitis as the key words. This article reviewed the mechanisms of BPH pathogenesis and anti-inflammatory effects of BoNT-A. The results suggested that to achieve effectiveness, the treatment of BPH with BoNT-A should be tailored according to more detailed clinical information and reliable biomarkers.

[Use of botulinum toxin A in pelvic floor dysfunctions in the elderly: A review]

INTRODUCTION

The present article is the final report of a multi-disciplinary meeting supported by the GRAPPPA (group for research applied to pelvic floor dysfunctions in the elderly). The objective was to conduct a comprehensive review on the role of botulinum toxin A (BonTA) in the treatment of pelvic floor dysfunctions in the elderly.

METHODS

The present article, written as a comprehensive review of the literature, combines data issued from the scientific literature with expert's opinions. Review of the literature was performed using the online bibliographic database MedLine (National Library of Medicine). Regarding intra-detrusor BonTA injections, only articles focusing on elderly patients (>65 yo) were included. Regarding other localizations, given the limited number of data, all articles reporting outcomes of BonTA were included, regardless of studies population age. In case of missing or insufficient data, expert's opinions were formulated.

RESULTS

Although, available data are lacking in this specific population, it appears that BonTA could be used in the non-fraily elderly patients to treat overactive bladder or even neurogenic detrusor overactivity, with a success rate comparable to younger population at 3 months (88.9% vs. 91.2%), 6 months (49.4% vs. 52.1%) and 12 months (23.1% vs. 22.3%), as well as a significant decrease in number of voids per day (11.4 vs. 5.29 P<0.001) and in the number of pads per day (4.0 vs. 1.3, P<0.01). Furthermore, BonTA is likely to be offered in the future as a treatment of fecal incontinence and obstructed defecation syndrome symptoms. Concerning bladder outlet obstruction/voiding dysfunction symptoms, intra-urethral sphincter BonTA should not be recommended.

CONCLUSION

BonTA injections are of interest in the management of various pelvic floor dysfunctions in the elderly, and its various applications should be better evaluated in this specific population in order to further determine its safety and efficacy.

Intraprostatic injections for lower urinary tract symptoms/benign prostatic enlargement treatment

INTRODUCTION

Endoscopic surgical treatment represents the gold standard in patients with lower urinary tract symptoms (LUTS) when medical treatment fails. In the past years there has been a growing interest in intraprostatic injections which represent a minimally invasive alternative for those patients not suitable for surgery. Aim of our study is to systematically review all the available data on intraprostatic injections for the treatment of LUTS patients with benign prostatic enlargement (BPE).

EVIDENCE ACQUISITION

A systematic review of the literature using the Medline, Scopus and Web of Science databases for relevant articles published until June 2018 was performed using both the Medical Subjects Heading and free test protocols. The MeSH search was conducted by combining the following terms: "Intraprostatic Injections," "Botulinum Toxin A," "Onabotulinum," "Ethanol," "Lower Urinary tract Symptoms," "Benign prostatic enlargement," "Benign Prostatic Hyperplasia," "NX1207," "PRX302." Each article's title and abstract were reviewed for their appropriateness and their relevance with regards to the relationship to intraprostatic injections.

EVIDENCE SYNTHESIS

Intraprostatic injections for the treatment of LUTS/BPE patients may be performed using different products as: ethanol, onabotulinum toxin A, NX1207 and PRX 302. Ethanol, the first agent for intraprostatic use, showed promising results in prospective trials, however, the rare but serious adverse events associated with extraprostatic diffusion of ethanol stopped its use. Many studies on onabotulinum toxin A (BotoxR) have been performed, however, two large randomized clinical trials showed no differences in terms of symptoms improvements and flow improvements when compared to placebo. Two new promising drugs NX 1207 and PRX 302 have been developped in the past years. NX 1207 showed lack of efficacy in the two large European phase III RCT. PRX 302 showed promising results in phase I and II studies, however, definitive results from a large phase III randomized controlled trial (RCT) are awaited before drawing any definitive conclusions.

CONCLUSIONS

Intraprostatic injections are still to be considered investigational for the minimally invasive management of LUTS/BPE patients. Emerging data suggest a possible role of new agents in the near future when definitive data of ongoing RCTs will be available.

Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology

The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects. Novel BoNTs are being discovered owing to next generation sequencing, but their biologic and pharmacological properties remain largely unknown. The molecular structure of the large protein complexes that the toxin forms with accessory proteins, which are included in some BoNT type A1 and B1 pharmacological preparations, have been determined. By far the largest effort has been dedicated to the testing and validation of BoNTs as therapeutic agents in an ever increasing number of applications, including pain therapy. BoNT type A1 has been also exploited in a variety of cosmetic treatments, alone or in combination with other agents, and this specific market has reached the size of the one dedicated to the treatment of medical syndromes. The pharmacological properties and mode of action of BoNTs have shed light on general principles of neuronal transport and protein-protein interactions and are stimulating basic science studies. Moreover, the wide array of BoNTs discovered and to be discovered and the production of recombinant BoNTs endowed with specific properties suggest novel uses in therapeutics with increasing disease/symptom specifity. These recent developments are reviewed here to provide an updated picture of the biologic mechanism of action of BoNTs, of their increasing use in pharmacology and in cosmetics, and of their toxicology.

Use of botulinum toxin for voiding dysfunction

The use of botulinum toxin A (BoNT-A) has expanded across a range of lower urinary tract conditions. This review provides an overview of the current indications for BoNT-A in the lower urinary tract and critically evaluates the published evidence within each area. The classic application of BoNT-A has been in the management of refractory neurogenic detrusor overactivity (NDO) and overactive bladder (OAB). There is a large volume of high-quality evidence, including numerous randomized placebo-controlled trials, which demonstrate the efficacy of BoNT-A over a long follow-up period. The culmination of this robust evidence-base has led to onabotulinumtoxin A (onaBoNT-A) receiving regulatory approval as a second-line treatment for NDO at a dose of 200 U and OAB at dose of 100 U. Other applications for BoNT-A are used on an off-license basis and include interstitial cystitis/bladder pain syndrome (IC/BPS), benign prostatic hyperplasia (BPH), and detrusor sphincter dyssynergia (DSD). These applications are associated with a less mature evidence-base although the literature is rapidly evolving. At present, the results for painful bladder syndrome (PBS) are promising and BoNT-A injections are recommended as a fourth line option in recent international guidelines, although larger randomized study with longer follow-up are required to confirm the initial findings. As a treatment for DSD, BoNT-A injections have shown potential but only in a small number of trials of limited quality. No definite recommendation can be made based on the current evidence. Finally, the results for the treatment of BPH have been variable and recent high quality randomized controlled trials (RCTs) have suggested no benefit over placebo so at present it cannot be recommended for routine clinical practice. Future advances of BoNT-A include liposome encapsulated formulations which are being developed as an alternative to intravesical injections.

Apoptotic action of botulinum toxin on masseter muscle in rats: early and late changes in the expression of molecular markers

The purpose of this study was to compare the early or late expression levels of p65, Bcl-2, and type II myosin and the frequency of TUNEL-positive nuclei in the rat masseter muscle after injection of different concentrations of botulinum toxin-A (BTX-A). We injected either 5 U or 10 U of BTX-A into both masseter muscles of the rat. As a control group, the same volume of saline was injected. After 2 or 12 weeks, the animals were sacrificed. Subsequently, a biopsy and immunohistochemical staining of the samples were performed using a p65, Bcl-2, or type II myosin antibody. Additionally, a TUNEL assay and transmission electron microscopic analysis were performed. The expression of p65, Bcl-2, and type II myosin increased significantly with increasing concentrations of BTX-A at 2 weeks after BTX-A injection (P < 0.05). The number of TUNEL-positive nuclei was also significantly increased in the BTX-A-treated groups in comparison to the saline-treated control at 2 weeks after BTX-A injection (P < 0.05). Elevated expression of Bcl-2 was also observed in 10-unit BTX-A-treated group at 12 weeks after injection (P < 0.05). At 12 weeks after injection, the number of enlarged mitochondria was increased, and many mitochondria displayed aberrations in cristae morphology after BTX-A injection. In conclusion, BTX-A injection into the masseter muscle increased the expression level of p65, Bcl-2, and type II myosin at an early stage. The morphological changes of mitochondria were more evident at 12 weeks after injection.

Botulinum Toxin A and Lower Urinary Tract Dysfunction: Pathophysiology and Mechanisms of Action

The use of onabotulinumtoxinA (BoNT-A) for the treatment of lower urinary tract diseases (LUTD) has increased markedly in recent years. The indications for BoNT-A treatment of LUTD now include neurogenic or idiopathic detrusor overactivity, interstitial cystitis/bladder pain syndrome and voiding dysfunction. The mechanisms of BoNT-A action on LUTDs affect many different aspects. Traditionally, the effects of BoNT-A were believed to be attributable to inhibition of acetylcholine release from the presynaptic efferent nerves at the neuromuscular junctions in the detrusor or urethral sphincter. BoNT-A injection in the bladder also regulated sensory nerve function by blocking neurotransmitter release and reducing receptor expression in the urothelium. In addition, recent studies revealed an anti-inflammatory effect for BoNT-A. Substance P and nerve growth factor in the urine and bladder tissue decreased after BoNT-A injection. Mast cell activation in the bladder also decreased. BoNT-A-induced improvement of urothelium function plays an important mitigating role in bladder dysfunction. Vascular endothelial growth factor expression in urothelium decreased after BoNT-A injection, as did apoptosis. Studies also revealed increased apoptosis in the prostate after BoNT-A injection. Although BoNT-A injection has been widely used to treat different LUTDs refractory to conventional treatment, currently, onabotulinumtoxinA has been proven effective only on urinary incontinence due to IDO and NDO in several large-scale clinical trials. The effects of onabotulinumtoxinA on other LUTDs such as interstitial cystitis, benign prostatic hyperplasia, dysfunctional voiding or detrusor sphincter dyssynergia have not been well demonstrated.

New intraprostatic injectables and prostatic urethral lift for male LUTS

Treatment modalities for male lower urinary tract symptoms (LUTS) comprise a broad spectrum of medical and surgical options. Interest is growing in minimally invasive treatment options, which should ideally be performed in an outpatient setting and have a short recovery time, durable efficacy and a good safety profile. The preservation of all aspects of sexual function, including antegrade ejaculation, seems to be increasingly important for patients. Initial experimental data on new minimally invasive procedures-such as the intraprostatic injection of novel agents including botulinum neurotoxin A (BoNT-A), NX-1207 and PRX302-were promising, but clinical trials have not confirmed the findings. Trials of the mechanical prostatic urethral lift device-Urolift(®) (Neotract, Inc., USA)-have been positive, but further long-term results are needed to confirm its beneficial effects.

Lower urinary tract symptoms in men

Benign prostatic hyperplasia (BPH) is a highly prevalent and costly condition that affects older men worldwide. Many affected men develop lower urinary tract symptoms, which can have a negative impact on their quality of life. In the past, transurethral resection of the prostate (TURP) was the mainstay of treatment. However, several efficacious drug treatments have been developed, which have transformed BPH from an acute surgical entity to a chronic medical condition. Specifically, multiple clinical trials have shown that α adrenoceptor antagonists can significantly ameliorate lower urinary tract symptoms. Moreover, 5α reductase inhibitors, alone or combined with an α adrenoceptor antagonist, can reverse the natural course of BPH, reducing the risk of urinary retention and the need for surgical intervention. Newer medical regimens including the use of antimuscarinic agents or phosphodiesterase type 5 inhibitors, have shown promise in men with predominantly storage symptoms and concomitant erectile dysfunction, respectively. For men who do not adequately respond to conservative measures or pharmacotherapy, minimally invasive surgical techniques (such as transurethral needle ablation, microwave thermotherapy, and prostatic urethral lift) may be of benefit, although they lack the durability of TURP. A variety of laser procedures have also been introduced, whose improved hemostatic properties abrogate many of the complications associated with traditional surgery.

Botulinum toxin A inhibits salivary secretion of rabbit submandibular gland

Botulinum toxin A (BTXA) has been used in several clinical trials to treat excessive glandular secretion; however, the precise mechanism of its action on the secretory function of salivary gland has not been fully elucidated. In this study, we aimed to investigate the effect of BTXA on secretion of submandibular gland in rabbits and to identify its mechanism of action on the secretory function of salivary gland. At 12 weeks after injection with 5 units of BTXA, we found a significant decrease in the saliva flow from submandibular glands, while the salivary amylase concentration increased. Morphological analysis revealed reduction in the size of acinar cells with intracellular accumulation of secretory granules that coalesced to form a large ovoid structure. Expression of M3-muscarinic acetylcholine receptor (M3 receptor) and aquaporin-5 (AQP5) mRNA decreased after BTXA treatment, and distribution of AQP5 in the apical membrane was reduced at 1, 2 and 4 weeks after BTXA injection. Furthermore, BTXA injection was found to induce apoptosis of acini. These results indicate that BTXA decreases the fluid secretion of submandibular glands and increases the concentration of amylase in saliva. Decreased expression of M3 receptor and AQP5, inhibition of AQP5 translocation, and cell apoptosis might involve in BTXA-reduced fluid secretion of submandibular glands.

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.

[New treatment strategies for male lower urinary tract symptoms]

For patients with lower urinary tract symptoms (LUTS), α1-adrenoreceptor inhibitors and 5-alpha reductase inhibitors as well as their combination are considered the gold standard. In addition, anticholinergic agents are being introduced as monotherapy or in combination with α1-adrenocepetor inhibitors for patients with predominant storage disorders. Phosphodiesterase 5 (PDE5) inhibitors are often the best option for patients with LUTS who also suffer from erectile dysfunction. Recently, novel treatment options have been presented and intraprostatic injection of various agents, such as botulinum toxin A, NX-1207 and PRX302 has shown promising initial results. In addition, innovative minimally invasive treatment options, such as UroLift® appear to be efficacious and safe in this patient cohort. Particular emphasis should be laid on patients with LUTS and concomitant sexual disorders.

[Intraprostatic injection therapy in patients with benign prostatic syndrome]

Intraprostatic injection therapy is a minimally invasive treatment of patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia and could be a therapeutic alternative in increasingly older and co-morbid patients. Nowadays only botulinum neurotoxin A (BoNT/A), absolute ethanol, NX-1207 and PRX302 are of relevance but none of these substances has yet been authorized for treatment use (off-label use). There have been only three randomized, placebo-controlled trials (RCTs) for BoNT/A, whereas none exist for ethanol and the results of existing studies are inconsistent and without convincing proof of efficacy. NX-1207 is a protein with selective pro-apoptotic properties and non-inferiority compared to finasteride has been demonstrated. PRX302 is a modified proaerolysin that can be activated by prostate-specific antigen and is therefore (prostate) cell-specific. Safety and efficacy are well documented; however, intraprostatic injection therapy should presently only be performed in clinical trials, irrespective of the substance used.

Treatment of lower urinary tract symptoms: agents for intraprostatic injection

When the currently available pharmacotherapeutic principles used for treatment of male lower urinary tract symptoms (LUTS) fail, transurethral resection of the prostate still remains the widely applied gold-standard therapy, since the majority of minimally invasive therapies have not achieved the same efficacy and/or lack an evidence base to support their routine use. Intraprostatic injection therapy, which probably is the oldest minimally invasive surgical treatment, has not been widely used, but recent reports of successful treatments with several new agents have renewed interest in this approach. Anhydrous ethanol still seems to be one of the most extensively studied injectables to date, but intraprostatic injection of botulinum toxin has received much recent attention, with regard to both its mechanism of action and efficacy. In addition, other agents such as NX-1207 and PRX302 have been reported to have promising effects. Injection therapy, using the transperineal, transrectal and transurethral routes for delivery of the active compounds, seems to be an effective minimally invasive surgical therapy for LUTS associated with benign prostatic hyperplasia (BPH). However, further studies on mechanisms of action of the novel agents used, and controlled clinical trials documenting their efficacy and side-effects (which are largely lacking), are needed before their place in the treatment of BPH/LUTS can be properly assessed.

Botulinum neurotoxin type A for the treatment of benign prostatic hyperplasia: randomized study comparing two doses

PURPOSE

To assess the efficacy and safety of intraprostatic injection of two botulinum neurotoxin type A (BoNT-A) doses for the treatment of benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

Men with symptomatic BPH who failed medical treatment were randomized to receive 100 U or 200 U of BoNT-A into the prostate. The International Prostatic Symptom Score (IPSS), maximum flow rate (Q(max)), post-void residual volume (PVR), PSA levels and prostate volume before injection and after 3 and 6 months were evaluated. Adverse events were compared between the groups.

RESULTS

Thirty four patients were evaluated, including 17 in the BoNT-A 100 U group and 17 in the BoNT-A 200 U group. Baseline characteristics were similar in both groups. Both doses produced significant improvements in IPSS, Q(max) and PVR after 3 and 6 months and both doses promoted comparable effects. Prostate volume was affected by 200 U BoNT-A injection only after 6 months of treatment. PSA levels were significantly affected in the 100 U group only after 6 months of treatment. In the 200 U group, PSA levels were significantly decreased after 3 and 6 months. The complication rate was similar in both groups.

CONCLUSIONS

Efficacy and safety of both BoNT-A doses are similar for BPH treatment in the short term followup.

Urodynamic effects of transrectal intraprostatic Ona botulinum toxin A injections for symptomatic benign prostatic hyperplasia

OBJECTIVE

To investigate urodynamic, symptomatic, and histologic effects of intraprostatic injection with Ona botulinum toxin A for benign prostatic hyperplasia.

METHODS

Patients >55 years with symptomatic benign prostatic hyperplasia failing medical therapy were treated. Inclusion criteria were International Prostate Symptom Score >7, prostate volume 30-50 cm(3), and urodynamic bladder outlet obstruction >Schäfer grade 2. A transrectal intraprostatic injection of 200 IU Ona botulinum toxin A was given. Filling cystometry and pressure flow studies were performed at 3, 6, and 12 months post injection. International Prostate Symptom Score, International Prostate Symptom Score quality of life, prostate-specific antigen, and prostate volume were measured up until 12 months; prostate biopsies before and after Ona botulinum toxin A injection were done for histology and cell proliferation.

RESULTS

Fifteen men (mean age 64.9 years) were included. Ona botulinum toxin A injection was well tolerated with few complications. Postvoid residual improved (170 to 80 mL), but maximum flow rate and bladder outlet resistance parameters did not change during follow-up. International Prostate Symptom Score and International Prostate Symptom Score quality of life improved (22 to 13 and 5 to 2, respectively), whereas prostate-specific antigen and prostate volume remained unaltered. Cell proliferation did not decrease and in 37% and 64% of pre- and posttreatment biopsies, respectively, some degree of prostatitis was found. Ten of 15 patients eventually underwent transurethral prostate resection because of persisting symptoms.

CONCLUSION

Intraprostatic Ona botulinum toxin A for symptomatic benign prostatic hyperplasia did not affect urodynamic outcomes, except for postvoid residual. Although symptom scores improved, we were not able to show change in prostate volume, prostate-specific antigen, or histologic outcomes. A placebo effect of intraprostatic Ona botulinum toxin A could not be ruled out.

Intra-prostatic injection of botulinum toxin type A in treatment of dogs with spontaneous benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common, naturally developing, age-related condition in dogs. The pathogenesis of BPH is not completely known; however, DHT is a hormone involved in enlargement of the prostate. Recently, the effect of botulinum toxin A (BT-A) was investigated in the rat and human prostate and has shown to induce atrophy of the gland on the canine prostate. This study investigated the effect of BT-A in the canine prostate and on the semen. Eight sexually intact male dogs with BPH (detected radiographically and ultrasonographically), and with clinical signs of BPH (e.g. hematuria or tenesmus) were used. Each lobe of the prostate received an injection of 125 U of BT-A with one-needle pass under transabdominal ultrasound guidance. The clinical results were evaluated at baseline and after treatment. No local complications or systemic adverse effects were reported. At 4 weeks, the mean prostate volume (PV) was not significantly changed after BT-A (from 17.70 ± 6.34 to 16.48 ± 5.98 cm(3)). At 8 weeks the PV had further decreased to 16.04 ± 5.80 cm(3), reaching its maximum effect, but that change was not significant. The results were maintained at 16 weeks. All dogs had normal libido, erection, and ejaculation during semen collection. No significant difference was observed in all seminal parameters. Results suggest that the administration of 250 U of BT-A do not contribute to PV reduction and do not adversely affect the semen quality of dogs with BPH.

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.

Emerging treatment options for benign prostatic obstruction

Benign prostatic obstruction (BPO) affects an increasing number of men with age. It can cause troublesome lower urinary tract symptoms, can have a negative impact on quality of life, and may be associated with significant morbidity. Currently available medication and surgical treatments are limited by adverse events, invasiveness, and patient compliance. This has driven research into the pathogenesis of benign prostatic hyperplasia and led to the development of novel pharmacological agents and minimally invasive therapeutic interventions. This review highlights emerging treatment options for BPO.

Injection therapy for prostatic disease: A renaissance concept

Purpose:

Initially conceived as an intervention for prostatic infection, injection therapy has been used to alleviate urinary retention, and is now primarily investigated for the treatment of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). For over a century, intraprostatic injection has been used as a minimally invasive surgical therapy (MIST), and is on the verge of a rebirth. This review will familiarize the reader with the origins and history of intraprostatic injection, and its evolution using transperineal, transrectal and transurethral routes with multiple injectants.

Materials and Methods:

A MEDLINE review of the literature on intraprostatic injections published between 1966 and 2007 was performed, augmented with articles and documents dating back to 1832.

Results:

Transperineal and transurethral injections have the most systematic evaluation in patients. There are advantages and disadvantages associated with each route. Most injectants consistently produce localized coagulative necrosis and gland volume reduction with varying degrees of LUTS relief. Anhydrous ethanol (AE) is the most extensively studied injected agent to date.

Conclusions:

Injection therapy is a promising minimally invasive treatment option for various prostatic conditions and has been examined for over 100 years. Further experience in systematic laboratory research and completion of currently ongoing clinical trials is necessary before widespread clinical application.

A review of botulinum toxin use for chronic pelvic pain syndrome

The inability of urologists to consistently and effectively treat men with chronic pelvic pain syndrome (CPPS), also known as chronic abacterial prostatitis, is a source of great frustration. Botulinum toxin (BTX), a potent neurotoxin, can act on most of the peripheral nerves of the pelvis through a variety of mechanisms. BTX injection therapy for CPPS treatment has shown modest improvements. BTX is ideal for integration into a multimodal treatment plan, which may help achieve pain relief in men with chronic pelvic pain.

Prostatic involution after intraprostatic injection of cobra toxin

PURPOSE

We evaluated the comparative effects of intraprostatic injection of cobra cardiotoxin D and botulinum toxin type A on prostate structure in the rat model.

MATERIALS AND METHODS

A total of 18 Sprague-Dawley® rats weighing 500 to 600 gm received a single 0.1 ml injection of saline (6), botulinum toxin type A (6) or the cardiotoxin D (6) component of cobra (Naja naja atra) toxin in the right and left ventral lobes of the prostate. At 14 days the rats were sacrificed. The prostate glands were harvested, weighed and processed for immunohistochemical and morphological studies.

RESULTS

Prostate glands injected with cardiotoxin D showed significantly decreased weight compared to that of prostates injected with botulinum toxin type A and the saline control. Prostatic atrophy in the glandular component with flattening of the epithelial lining was seen histologically in rats that received botulinum toxin and cardiotoxin D. Each group injected with cardiotoxin D and botulinum toxin showed a significant increase in the number of apoptotic cells compared with controls while only the botulinum toxin group showed a significant increase in the number of proliferating cells. Only rats injected with botulinum toxin had body weight loss.

CONCLUSIONS

Our study shows that intraprostatic injection of cobra cardiotoxin D induces prostatic atrophy and leads to a decrease in prostatic weight greater than that of intraprostatic injection of botulinum toxin type A. No systemic effects, such as decreased body weight, were noted after cardiotoxin D injection. Further studies are warranted but the statistically significant decrease in the number of proliferating cells implies a prolonged effect of cardiotoxin D.

Botulinum neurotoxin A for benign prostatic hyperplasia

PURPOSE OF REVIEW

The injection of botulinum neurotoxin A (BoNT-A) into the prostate represents an alternative, minimal invasive treatment for lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH), which gained the interest of urologists during the last years, although it is not yet licensed. The purpose of this review is to summarize the mechanisms through which BoNT-A could inhibit the progression of BPH and eliminate the lower urinary tract symptoms according to the findings of animal studies. Furthermore, we review clinical studies to report the efficacy and safety of intraprostatic BoNT-A injection according to various injection protocols.

RECENT FINDINGS

The experimental studies report induced relaxation of the prostate, atrophy, and reduction in its size through inhibition of the trophic effect of the autonomic system on the prostate gland. Also, a possible mechanism of reduction in lower urinary tract symptoms might take place through inhibition of sensory afferents from the prostate to the spinal cord. Clinical studies report symptomatic relief and improvement in the measured parameters during the follow-up period, whereas local or systematic side-effects are rare.

SUMMARY

We should recognize that, at present, this therapy is still experimental. Although the results of the clinical studies are encouraging, the level of evidence is low. Clearly, we need large-scale, clinical, placebo-controlled, randomized studies, including long-term surveillance to document the evidence of this therapy and, eventually, to register BoNT-A for this indication.

Intraprostatic botulinum toxin injection in patients with benign prostatic enlargement

Histological evidence of benign prostatic hyperplasia (BPH) exceeded 50% in men over 50 years of age and rose to 75% as men entered the eighth decade. Therapeutic options for BPH generally fall into one of the three categories: watchful waiting, medical treatment and surgery. Excluding watchful waiting, the other forms of intervention directed at modifying the physiologic effects of BPH with or without directly altering the prostatic mass or its configuration come with varying effectiveness and risk. Botulinum toxin (BTX-A) produce inhibition of acethylcholine release at the neuromuscular junction causes paralyzing effects and atrophy of striated as well as the smooth muscle fiber. BTX-A also causes inhibitory effects on the ganglionic and post-ganglionic fibres of autonomic nervous system inducing diffuse atrophy and apoptosis of nasal and prostate glands. Clinical series demonstrates efficacy of BTX-A in alleviating symptoms induced by BPH. Larger randomized clinical trials studies are necessary in order to identify the mechanisms by which BTX-A affects the prostate, the ideal dose and the duration of effect. BTX-A injected into prostate appears safe and effective.

Intraprostatic Botulinum Toxin Type A injection in patients with benign prostatic enlargement: duration of the effect of a single treatment

Background

Botulinum Toxin Type-A (BoNT/A) intraprostatic injection can induce prostatic involution and improve LUTS and urinary flow in patients with Benign Prostatic Enlargement (BPE). However, the duration of these effects is unknown. The objective of this work was to determine the duration of prostate volume reduction after one single intraprostatic injection of 200U of Botulinum Toxin Type-A.

Methods

This is an extension of a 6 month study in which 21 frail elderly patients with refractory urinary retention and unfit for surgery were submitted to intraprostatic injection of BoNT/A-200U, by ultrasound guided transrectal approach. In spite of frail conditions, eleven patients could be followed during 18 months. Prostate volume, total serum PSA, maximal flow rate (Qmax), residual volume (PVR) and IPSS-QoL scores were determined at 1, 3, 6, 12 and 18 months post-treatment.

Results

Mean prostate volume at baseline, 82 ± 16 ml progressively decreased from month one coming to 49 ± 9,5 ml (p = 0,003) at month six. From this moment on, prostate volume slowly recovered, becoming identical to baseline at 18 months (73 ± 16 ml, p = 0.03). Albeit non significant, serum PSA showed a 25% decrease from baseline to month 6. The 11 patients resumed spontaneous voiding at month one. Mean Qmax was 11,3 ± 1,7 ml/sec and remained unchanged during the follow-up period. PVR ranged from 55 ± 17 to 82 ± 20 ml and IPSS score from10 to 12 points.

Conclusion

Intraprostatic BoNT/A injection is safe and can reduce prostate volume for a period of 18 months. During this time a marked symptomatic improvement can be maintained.

Botulinum toxin type A inhibits the growth of LNCaP human prostate cancer cells in vitro and in vivo

INTRODUCTION AND OBJECTIVE

Botulinum toxin type A (BTA) intraprostatic injection induces an improvement of urinary symptoms related to benign prostatic hypertrophy (BPH). Infra-clinical prostate cancer (PCa) foci and pre-neoplasic lesions occur concomitantly with BPH in a significant number of patients. The objective of this study was to address whether BTA influences the growth of prostate tumors.

METHODS

Proliferation of PC-3 and LNCaP cell lines exposed or not to BTA (Botox) was assessed and compared. Presence of synaptic vesicle 2 (SV2) protein, the membrane receptor of BTA, was studied in both cell lines. After nude mice bearing LNCaP xenografts received intra-tumoral BTA or saline injection, tumor volume, serum PSA, histopathology and detection of apoptosis were comparatively assessed.

RESULTS

BTA significantly reduced LNCaP cell proliferation and increased apoptosis in a dose-dependent manner but did not affect PC-3. The SV2 receptor was present in both cell lines at a ratio of 4:1 (LNCaP/PC-3). One unit of BTA resulted in a significantly lower growth rate and slower PSA progression over 28 days compare to controls. The tumors were morphologically similar. There were significantly more apoptotic cells compared to controls.

CONCLUSION

BTA inhibits the growth of LNCaP human PCa cells in vitro and in vivo. These findings indicate that intra-prostatic BTA injections to treat BPH are unlikely to promote the growth of co-existing infra-clinical PCa foci in men. A potential inhibitory effect of BTA on the growth of human PCa should be further studied.

Therapeutic effects of add-on botulinum toxin A on patients with large benign prostatic hyperplasia and unsatisfactory response to combined medical therapy

OBJECTIVE

Botulinum toxin A (BoNT-A) injections into the prostate have been reported to be effective and durable in the treatment of small benign prostatic hyperplasia (BPH). This study evaluated the effectiveness of BoNT-A in patients with large BPH with an unsatisfactory response to combined alpha-blocker and 5-alpha-reductase inhibitor therapy.

MATERIAL AND METHODS

Sixty patients with BPH and total prostate volume (TPV) of > 60 ml with unsatisfactory response to combination medical therapy were randomly assigned to receive add-on intraprostatic BoNT-A injection (n=30) or continued medical therapy (control group). Patients in the treatment group received 200-600 U of Botox injected into the prostate. Outcome parameters including International Prostate Symptom Score (IPSS), quality of life index (QoL-I), TPV, maximum flow rate (Q(max)) and postvoid residual (PVR) were compared between treatment and control groups at baseline, 6 months and 12 months.

RESULTS

Significant decreases in IPSS, QoL-I and TPV, and increase in Q(max) were observed at 6 months and remained stable at 12 months in the treatment group. Improvements in IPSS and QoL-I were also observed at 6 months and a decrease in TPV at 12 months was noted in the control group. However, no significant changes in any parameters except for QoL-I at 6 and 12 months were noted between the treatment and control groups. Acute urinary retention developed in three patients receiving BoNT-A treatment. Three BoNT-A and two medical treatment patients converted to transurethral surgery at the end of study.

CONCLUSIONS

This study shows that add-on prostatic BoNT-A medical treatment can reduce prostate volume and improve lower urinary tract symptom score and QoL-I within 6 months in the treatment of large BPH. However, the therapeutic effect at 12 months was similar to combination medical treatment.

Persistent detrusor overactivity after transurethral resection of the prostate

Detrusor overactivity is associated with aging and benign prostatic obstruction and often causes the troublesome symptoms of urgency and urgency incontinence (overactive bladder), persistent detrusor overactivity after transurethral resection of the prostate being the cause of more than a third of poor symptomatic outcomes following surgery. Most of the evidence currently suggests that neurons of the urothelium at the bladder neck play a significant role in the genesis of detrusor overactivity. Treatment options including botulinum toxin injections and intravesical vanilloids have been studied in the treatment of persistent detrusor overactivity, but further studies are needed specifically in patients with persistent detrusor overactivity after transurethral resection of the prostate. As urodynamic studies are able to predict a proportion of postoperative failures, more widespread use is advocated by many in the routine assessment of lower urinary tract symptoms thought to be due to benign prostatic obstruction.

Relief by botulinum toxin of lower urinary tract symptoms owing to benign prostatic hyperplasia: early and long-term results

OBJECTIVES

To present a comprehensive experience with intraprostatic botulinum toxin (BT) injection in men with symptomatic benign prostatic hyperplasia (BPH).

METHODS

In this open-label study using an outpatient setting, 77 men with BPH received 200 intraprostatic BT A units (Botox) using an ultrasound-guided transperineal approach. We evaluated the American Urological Association (AUA) score, serum prostate-specific antigen (PSA), prostatic volume, residual volume, and peak urinary flow rates. The primary endpoint was symptomatic improvement after treatment, as measured by means of AUA score and peak urinary flow rates. The secondary endpoint was the evaluation of prostatic volume, serum PSA, and residual urinary volume.

RESULTS

No significant local effects occurred. At their 1-month evaluation, 41 patients had subjective symptomatic relief. Compared with baseline values, AUA score was reduced from 24.1 +/- 4.6 to 12.6 +/- 2.9 (P = .00001), and serum PSA from 6.2 +/- 1.7 to 4.8 +/- 1.0 ng/mL (P = .03). At the same time, prostatic volume and residual urine volume were reduced by 12.7% and 12.8%, respectively, and mean peak urinary flow rate increased (P = .01). At 2 months' evaluation, 55 patients had subjective symptomatic relief. AUA score was reduced by 63.9% (P = .00001) compared with baseline values. In the same patients, serum PSA, prostatic volume, and residual urine volume were reduced by 51.6% (P = .00001), 42.8% (P = .00001), and 55.9% (P = .002), respectively, and mean peak urinary flow rate increased significantly.

CONCLUSIONS

Intraprostatic BT seems to be a promising approach to the treatment of BPH. It is safe, effective, well-tolerated, and not related to the patient's willingness to complete treatment.

Inhibition of prostate efferent neurotransmission by amikacin

BACKGROUND

It has been suggested that manipulation of the autonomic nerve supply to the prostate leads to loss of functional and structural integrity of the gland, and that these changes may be useful in treating prostatic diseases. This study investigates the effect of amikacin on prostate efferent neurotransmission in vitro, in both rat and human prostate samples.

METHODS

Prostate samples, obtained from male Wistar rats and 8 patients undergoing endoscopic surgery for benign prostatic hyperplasia, were studied by measurement of isometric contraction induced by electrical field stimulation (EFS), noradrenalin, carbachol, serotonin and ATP, in the presence or absence of amikacin 10(-3) M in a low-Ca medium.

RESULTS

Amikacin significantly reduced EFS-induced contraction of isolated rat and human prostate samples by 45 +/- 6.5% (P < 0.01) and 47 +/- 6% (P < 0.01), respectively. Contraction was restored after addition of calcium chloride 2 x 10(-3) M. Amikacin-induced relaxation in rat prostate samples was greater than the effect of magnesium and weaker than those of prazosin and verapamil, but comparable in extent with the latter. No significant effect was observed on rat prostate contractile response to noradrenaline as to ATP in the presence of amikacin. Rat prostate contraction to carbachol and serotonin was inhibited by 35 +/- 11% (P < 0.05) and 59 +/- 11.7% (P < 0.01), respectively, after addition of amikacin 10(-3) M.

CONCLUSIONS

Amikacin reduces in vitro both rat and human prostate contraction elicited by pre-junctional stimulation, but does not affect prostate contraction evoked by post-junctional stimulation. Our results indicate that amikacin affects prostatic efferent neurotransmission.