Botox-induced prostatic involution

Neuroepithelial Interactions in Cancer

Nerves not only regulate the homeostasis and energetic metabolism of normal epithelial cells but also are critical for cancer, as cancer recapitulates the biology of neural regulation of epithelial tissues. Cancer cells rarely develop in denervated organs, and denervation affects tumorigenesis, in vivo and in humans. Axonogenesis occurs to supply the new malignant epithelial growth with nerves. Neurogenesis happens later, first in ganglia around organs or the spinal column and subsequently through recruitment of neuroblasts from the central nervous system. The hallmark of this stage is regulation of homeostasis and energetic metabolism. Perineural invasion is the most efficient interaction between cancer cells and nerves. The hallmark of this stage is increased proliferation and decreased apoptosis. Finally, carcinoma cells transdifferentiate into a neuronal profile in search of neural independence. The latter is the last stage in neuroepithelial interactions. Treatments for cancer must address the biology of neural regulation of cancer.

Tumour innervation and neurosignalling in prostate cancer

Prostate cancer progression has been shown to be dependent on the development of autonomic nerves into the tumour microenvironment. Sympathetic nerves activate adrenergic neurosignalling that is necessary in early stages of tumour progression and for initiating an angiogenic switch, whereas parasympathetic nerves activate cholinergic neurosignalling resulting in tumour dissemination and metastasis. The innervation of prostate cancer seems to be initiated by neurotrophic growth factors, such as the precursor to nerve growth factor secreted by tumour cells, and the contribution of brain-derived neural progenitor cells has also been reported. Current experimental, epidemiological and clinical evidence shows the stimulatory effect of tumour innervation and neurosignalling in prostate cancer. Using nerves and neurosignalling could have value in the management of prostate cancer by predicting aggressive disease, treating localized disease through denervation and relieving cancer-associated pain in bone metastases.

Influence of the neural microenvironment on prostate cancer

BACKGROUND

Nerves are key factors in prostate cancer (PCa), but the functional role of innervation in prostate cancer is poorly understood. PCa induced neurogenesis and perineural invasion (PNI), are associated with aggressive disease.

METHOD

We denervated rodent prostates chemically and physically, before orthotopically implanting cancer cells. We also performed a human neoadjuvant clinical trial using botulinum toxin type A (Botox) and saline in the same patient, before prostatectomy.

RESULT

Bilateral denervation resulted in reduced tumor incidence and size in mice. Botox treatment in humans resulted in increased apoptosis of cancer cells in the Botox treated side. A similar denervation gene array profile was identified in tumors arising in denervated rodent prostates, in spinal cord injury patients and in the Botox treated side of patients. Denervation induced exhibited a signature gene profile, indicating translation and bioenergetic shutdown. Nerves also regulate basic cellular functions of non-neoplastic epithelial cells.

CONCLUSION

Nerves play a role in the homeostasis of normal epithelial tissues and are involved in prostate cancer tumor survival. This study confirms that interactions between human cancer and nerves are essential to disease progression. This work may make a major impact in general cancer treatment strategies, as nerve/cancer interactions are likely important in other cancers as well. Targeting the neural microenvironment may represent a therapeutic approach for the treatment of human prostate cancer.

Lysozyme gene treatment in testosterone induced benign prostate hyperplasia rat model and comparasion of its' effectiveness with botulinum toxin injection

OBJECTIVES

To compare the effects and histopathological changes of botulinum neurotoxin type A and lysozyme gene injections into prostate tissue within a testosterone induced benign prostate hyperplasia rat model.

MATERIALS AND METHODS

40 male Wistar rats were randomized into four Groups. Group-1: Control, Group-2: Testosterone replacement, Group-3: Testosterone+botulinum neurotoxin type A, Group-4: Testosterone+plazmid DNA/liposome complex.

RESULTS

Estimated prostate volume of the testosterone injected Groups were higher than the control (p <0.05). Actual prostate weight of the testosterone injected Groups was higher than the control Group (p <0.05). Testosterone undecanoate increased the prostate weight by 39%. Botulinum neurotoxin type A treatment led to an estimated prostate volume and actual prostate weights decreased up to 32.5% in rats leading to prostate apoptosis. Lysozyme gene treatment led to an estimated prostate volume and actual prostate weights decrease up to 38.7%.

CONCLUSION

Lysozyme gene and botulinum neurotoxin type A treatments for prostate volume decreasing effect have been verified in the present study that could be anew modality of treatment in prostatic benign hyperplasia that needs to be verified in large randomized human experimental studies.

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.

Effect of Onabotulinum Toxin A on Substance P and Receptor Neurokinin 1 in the Rat Ventral Prostate

INTRODUCTION

The objective of this work is to examine if sensory innervation impacts lower urinary tract symptoms (LUTS). Onabotulinum toxin A (BoNTA) has been used for the treatment of overactive and neurogenic bladder and as a treatment for LUTS secondary to benign prostatic hyperplasia (BPH). The mechanism of how BoNTA impacts LUTS/BPH is unclear. In rats, BoNTA injection causes prostate denervation, apoptosis and atrophy. In clinical trials reduced prostate size and LUTS are observed inconsistently, suggesting a neurologic component. We will examine if BoNTA treatment inhibits substance P production in sensory nerve fibers in the rat prostate.

METHODS

Twenty Sprague Dawley rats were divided into four groups including 1X PBS (control, n=6), 2.5 units Onabotulinum toxin A (BoNTA, n=6), 5 units BoNTA (n=6) injected into both lobes of the ventral prostate (VP) and sham surgery (n=2). Rats were Euthanized after one week. Substance P and its receptor neurokinin 1 localization and quantification were performed by counting the number of stained neurons and nerve bundles, by semi-quantitative immunohistochemical analysis and by western analysis.

RESULTS

Substance P was localized in neuronal axons and bundles in the stroma of the VP but not in the epithelium. Receptor neurokinin 1 was identified in neuronal bundles of the stroma and in columnar epithelium of the VP ducts. Substance P decreased ~90% after BoNTA treatment (p=0.0001) while receptor neurokinin 1 did not change by IHC (p=0.213) or Western (p=0.3675).

CONCLUSIONS

BoNTA treatment decreases substance P in the rat VP.

Intraprostatic Botulinum Neurotoxin Type A Injection for Benign Prostatic Hyperplasia-A Spotlight in Reality

Botulinum toxin is a neurotoxin produced by the bacterium Clostridium botulinum. It inhibits the release of acetylcholine and other neurotransmitters from the nerve terminal. Botulinum toxin, specifically toxin type A (BoNT-A) has been used since the 1970s to reduce the muscular hypercontraction disorders. The application of BoNT-A in urology field started from intra-bladder injection for overactive bladder, which has been recognized as third line therapy in many countries. Since prostate gland as well as bladder is under the influence of autonomic innervation, theorectically, injection of BoNT-A into the prostate induces chemo-denervation and modulation of prostate function, and reduces lower urinary tract symptoms (LUTS). This article reviews the application of BoNT-A in patients with LUTS/ benign prostatic hyperplasia (BPH) from mechanisms of action to clinical results. BoNT-A has been shown to induce prostate apoptosis, downregulation of alpha 1A receptors, and reduce contractile function of prostate in animal studies. Open studies of intraprostate BoNT-A injection have demonstrated promising results of reducing LUTS and improvement of voiding function in human LUTS/BPH, however, intraprostatic BoNT-A injection did not perform better than the placebo group in recent publications of placebo controlled studies. We suggested that BoNT-A prostate injection might benefit selected population of BPH/LUTS, but it is unlikely to be an effective therapy for general population of male LUTS/BPH.

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.

[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.

New emerging technologies in benign prostatic hyperplasia

PURPOSE OF REVIEW

Transurethral resection of the prostate has long been held as the gold standard for treatment of benign prostatic hyperplasia (BPH); however, there have been significant innovations in other less invasive alternative treatments for BPH in recent years. Our purpose is to present emerging surgical treatment modalities which have been presented in the last 12 months.

RECENT FINDINGS

We report recent results in different treatment options for BPH. The concept of stenting the urethra has already been introduced nearly 20 years ago in urology and like intraprostatic injection of botulinum toxin it has found application in urological treatment of bladder outlet obstruction. The prostatic urethral lift procedure is a novel surgical minimal invasive approach needing long-term results. Intraprostatic injections with NX-1207 and histotripsy fractionation of prostate tissue are treatment modalities, which are currently under evaluation for a clinical application in humans.

SUMMARY

Anaesthesia-free outpatient capability, lack of sexual side-effects and avoidance of actual surgery are attractive to patient and clinician alike. Some of the presented treatments may establish in clinical practice as a suitable treatment alternative to transurethral resection of the prostate and medical therapy.

Prostate volume in male patients with spinal cord injury: a question of nerves?

OBJECTIVE

To assess the influence of standardized complete surgical deafferentation of the lower urinary tract by sacral deafferentation (SDAF) and sacral anterior root stimulation (SARS) on prostate volume in men with spinal cord injury (SCI).

PATIENTS AND METHODS

In a prospective study, the prostate volume of men with SCI who underwent SDAF/SARS was measured using transrectal ultrasonography. The prostate volumes of these men were compared with those of men with complete SCI but who did not undergo SDAF/SARS, those of men with incomplete SCI, and those of a historical sample of able-bodied men.

RESULTS

The median [25th;75th percentile] prostate volume of men who underwent SDAF/SARS (20.0 [14.0; 29.0]) and of men with complete SCI who did not undergo SDAF/SARS (20.0 [16.5; 29.0]) was significantly smaller than in the reference group (25.0 [5.0; 84.0]). The mean prostate volume was associated with age in the reference group (r = 0.185; P < 0.001) and in men with incomplete SCI (r = 0.284; P = 0.031), but not in men with complete SCI, irrespective of SDAF/SARS.

CONCLUSIONS

The prostate volume of men with complete SCI was significantly smaller than that of able-bodied men. Our data imply that sustained central innervation of the prostate plays an important role in prostate growth.

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.

Botulinum toxin injection for lower urinary tract dysfunction

Botulinum toxin has been recently accepted as a novel treatment for lower urinary tract dysfunctions refractory to conventional treatment. Review of the clinical trials in recent years, botulinum toxin type A has been widely used in the urethra or urinary bladder to treat voiding dysfunction due to detrusor sphincter dyssynergia, incontinence due to neurogenic or idiopathic detrusor overactivity, sensory disorders such as bladder hypersensitivity, overactive bladder, and interstitial cystitis/painful bladder syndrome. Intravesical botulinum toxin type A injection is effective in treatment of urinary incontinence due to detrusor overactivity in men and women, as well as in children. Currently botulinum toxin type A has also been applied to treat lower urinary tract symptoms due to benign prostatic hyperplasia in patients not suitable for surgery. This article reviewed the recent advances of botulinum toxin type A on lower urinary tract dysfunction.

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.

Effects of 100 and 300 units of onabotulinum toxin A on lower urinary tract symptoms of benign prostatic hyperplasia: a phase II randomized clinical trial

PURPOSE

We conducted a 2-stage, multicenter, double-blind, randomized phase II clinical trial of 100 and 300 unit doses of onabotulinum toxin A to treat the lower urinary tract symptoms of benign prostatic hyperplasia.

MATERIALS AND METHODS

Men 50 years old or older with clinically diagnosed benign prostatic hyperplasia, American Urological Association symptom index 8 or greater, maximum urinary flow rate less than 15 ml per second, voided volume 125 ml or greater, and post-void residual 350 ml or less were randomized to prostatic transrectal injection of 100 or 300 units of onabotulinum toxin A. The primary outcome was at least 30% improvement from baseline to 3 months in American Urological Association symptom index and/or maximum urinary flow rate and safety. The men were followed for 12 months.

RESULTS

A total of 134 men were randomized and treated (68 with 100 units, 66 with 300 units), with 131 assessed at 3 months and 108 assessed at 12 months. Each dose met the 3-month primary outcome criteria. In the 100 unit arm the mean baseline American Urological Association symptom index of 18.8 decreased by 7.1 and 6.9 at 3 and 12 months, respectively. In the 300 unit arm the baseline of 19.5 decreased by 8.9 and 7.1, respectively. In the 100 unit arm the mean baseline maximum urinary flow rate of 10.0 ml per second increased by 2.5 and 2.2, respectively, and in the 300 unit arm the baseline of 9.6 increased by 2.6 and 2.3, respectively.

CONCLUSIONS

The intraprostatic injection of 100 or 300 units of onabotulinum toxin A passed predetermined criteria for treatment efficacy and safety, and a randomized trial with either dose is warranted. The 100 unit dose may be preferable due to similar efficacy with reduced costs and adverse effects.

Relative influence of testosterone and insulin in the regulation of prostatic cell proliferation and growth

Prostatic hyperplasia is a common problem of the aged men population. Recent experimental and clinical studies provide sufficient evidence that apart from androgens, insulin also plays an important role in the pathogenesis of prostatic hyperplasia. The present study was aimed to investigate the relative influence of testosterone and insulin on the cellular proliferation and prostatic growth. Effect of testosterone on the prostate of hypoinsulinemic, and glandular injection of insulin-receptor antagonist S961 on the prostate of castrated Sprague-Dawley rat (220±10 g) was examined. Significant decrease in the weight of the ventral prostate was observed in the streptozotocin-induced hypoinsulinemic rats (~6 fold), which is restored by the intervention of testosterone. Although, glandular injection of S961 did not led to any change in the frequency of proliferating cell nuclear antigen (PCNA) positive cells in normal rats, significant decrease was observed in the castrated rats. Castration led to increase in the frequency of the caspase-3 and the TUNEL positive cells in the ventral prostate. Further, long-term (6 weeks) administration of S961 induced significant decrease in the weight of the ventral prostate. Results of the present study provide that both testosterone and insulin promote prostatic cell proliferation and change in the level of either of the hormone results in the destabilization of cellular equilibrium, and modulation of the insulin-receptor signaling in the prostate may provide an alternative strategy for the treatment of prostatic enlargement. Further, studies are required to better understand the interplay between these hormones in the regulation of prostatic growth.

Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A

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

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.

Minimally invasive application of botulinum toxin A in patients with idiopathic rhinitis

Background

Nasal hypersecretion due to idiopathic rhinitis can often not be treated sufficiently by conventional medication. Botulinum toxin A (BTA) has been injected into the nasal mucosa in patients with nasal hypersecretion with a reduction of rhinorrhea lasting for about 4 to 8 weeks. Since the nasal mucosa is well supplied with glands and vessels, the aim of this study was to find out if the distribution of BTA in the nasal mucosa and a reduction of nasal hypersecretion can also be reached by a minimally invasive application by sponges without an injection.

Methods

Patients were randomly divided into two groups. The effect of BTA (group A, C, D) or saline as placebo (group B) was investigated in 20 patients with idiopathic rhinitis by applying it with a sponge soaked with BTA (40 units each nostril) or saline. Subgroups C and D contained these patients of group A and B who did not improve in symptoms one week after the original treatment (either BTA or saline) who then received the alternative medication. Changes of symptoms (rhinorrhea, nasal obstruction) were scored by the patients in a four point scale and counted (consumption of tissues, sneezing) in a diary. The patients were followed up weeks 1, 2, 4, 8 and 12.

Results

There was a clear reduction of the amount of secretion in group A compared to group B, C and D. This did not correlate with the tissue consumption, which was comparably reduced in group A and B, but reduced less in group C and D. Sneezing was clearly reduced in group A but comparably unchanged in group B and C and increased in group D. Nasal congestion remained unchanged.

Conclusion

In some patients with therapy-resistant idiopathic rhinitis BTA applied with a sponge is a long-lasting and minimal invasive therapy to reduce nasal hypersecretion.

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.