Vanilloids and the overactive bladder

Intravesical vanilloids for treating neurogenic lower urinary tract dysfunction in patients with multiple sclerosis: A systematic review and meta-analysis. A report from the Neuro-Urology Promotion Committee of the International Continence Society (ICS)

AIMS

To systematically assess all available evidence on efficacy and safety of vanilloids for treating neurogenic lower urinary tract dysfunction (NLUTD) in patients with multiple sclerosis (MS).

METHODS

This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were identified by electronic search of Cochrane register, Embase, Medline, Scopus, (last search January 8, 2016).

RESULTS

After screening of 7848 abstracts, 4 randomized controlled trials (RCTs) and 3 prospective cohort studies were included. Pooled data from three RCTs evaluating intravesical capsaicin showed the standardized mean difference to be -2.16 (95% confidence interval [CI] -2.87 to -1.45) in incontinence episodes per 24 h and -0.54 (95%CI -1.03 to -0.05) in voids per 24 h. There was no statistically significant effect on maximum cystometric capacity and maximum storage detrusor pressure. Overall, adverse events were reported by >50% of the patients, most commonly were pelvic pain, facial flush, worsening of incontinence, autonomic dysreflexia, urinary tract infection and haematuria. Risk of bias and confounding was relevant in both RCTs and non-RCTs.

CONCLUSIONS

Preliminary data suggest that intravesical vanilloids might be effective for treating NLUTD in patients with MS. However, the safety profile seems unfavorable, the overall quality of evidence is low and no licensed substance is currently available warranting well-designed, adequately sampled and properly powered RCTs.

Conservative bladder management in advanced multiple sclerosis

Anticholinergics and intermittent catheterization are the cornerstones of bladder management in early multiple sclerosis (MS). In advanced MS however, bladder management is based more on tradition than on evidence. Nurses seem to deal with catheter problems and chronic incontinence. Despite the abundant use of indwelling catheters, there is a lack for guidelines on catheter-induced problems. The psychosexual and social impact of bladder problems in advanced MS is often neglected. The international multidisciplinary special interest group on sexual, urological and bowel dysfunction in MS (SUBDIMS) as a special interest group of the Rehabilitation in Multiple Sclerosis (RIMS) was confronted with a high variability in practice and a lack of guidelines. A literature review was prepared during three multidisciplinary expert meetings. This review will be the basis of further initiatives to improve the urological treatment of patients with advanced MS.

The role of transient receptor potential cation channels in Ca2+ signaling

The 28 mammalian members of the super-family of transient receptor potential (TRP) channels are cation channels, mostly permeable to both monovalent and divalent cations, and can be subdivided into six main subfamilies: the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and the TRPA (ankyrin) groups. TRP channels are widely expressed in a large number of different tissues and cell types, and their biological roles appear to be equally diverse. In general, considered as polymodal cell sensors, they play a much more diverse role than anticipated. Functionally, TRP channels, when activated, cause cell depolarization, which may trigger a plethora of voltage-dependent ion channels. Upon stimulation, Ca2+ permeable TRP channels generate changes in the intracellular Ca2+ concentration, [Ca2+]i, by Ca2+ entry via the plasma membrane. However, more and more evidence is arising that TRP channels are also located in intracellular organelles and serve as intracellular Ca2+ release channels. This review focuses on three major tasks of TRP channels: (1) the function of TRP channels as Ca2+ entry channels; (2) the electrogenic actions of TRPs; and (3) TRPs as Ca2+ release channels in intracellular organelles.

Hyperosmolarity alters micturition: a comparison of urinary bladder motor activity in hyperosmolar and cyclophosphamide-induced models of overactive bladder

Hyperosmolar factors induce the neurogenic inflammatory response, leading to bladder overactivity (OAB). The aim of the study was to compare the bladder motor activity in a hyperosmolar and acute cyclophosphamide (CYP)-induced model of OAB. Furthermore, we set our sights on defining the most physiological model of OAB in experimental practice. Forty-two female rats were divided randomly into 5 groups. All animals underwent cystometry with the usage of isotonic saline or saline of increasing concentration. Acute chemical cystitis was induced by CYP to elicit OAB. The following cystometric parameters were analyzed: basal pressure, threshold pressure, micturition voiding pressure, intercontraction interval, compliance, functional bladder capacity, motility index, and detrusor overactivity index. CYP and hypertonic saline solutions induced OAB. Having been compared with CYP OAB, none of the rats infused with hypertonic solution exhibited macroscopic signs of bladder inflammation. The comparison of CYP and hyperosmolar models of OAB revealed that the greatest similarity existed between the 2080 mOsm/L OAB model and the acute CYP-induced model. We postulate that the 2080 mOsm/L model of OAB can be established as being a less invasive and more physiological model when compared with the CYP-induced OAB model. Additionally, it may also be a more reliable experimental tool for evaluating novel therapeutics for OAB as compared with CYP-induced models.

Where is TRPV1 expressed in the bladder, do we see the real channel?

Transient receptor potential channel-vanilloid subfamily member 1 (TRPV1) is an important target in the treatment of bladder overactivity. This receptor is suggested to function as a mechanosensor in the normal bladder and to mediate the development of bladder overactivity during cystitis. Our aim was to determine the cellular distribution of TRPV1 in mouse and rat bladder tissue. We used three different commercial TRPV1 antibodies to perform immunohistochemistry on bladder tissue from rats and wild-type and TRPV1(-/-) mice, using trigeminal ganglia as a control tissue for TRPV1 expression. Although two of the antibodies seemed to react specifically in trigeminal ganglion tissue, all the antibodies produced a similar staining pattern in the urothelium of wild-type and TRPV1(-/-) mice. These data show that TRPV1 antibodies can cause an aspecific immunostaining in bladder tissue, urging for additional research to confirm the exact distribution of TRPV1 in bladder. In conclusion, we think that the use of negative controls on knockout mice, whenever available, is mandatory when conducting immunohistochemical localization studies.

The molecular basis of urgency: regional difference of vanilloid receptor expression in the human urinary bladder

AIM

Treatments targeting vanilloid receptor TRPV1 are effective in some bladder disorders. Our aim was to determine the expression profiles of TRPV1 in regions of human bladder and test the hypothesis that there would be an upregulation of TRPV1 in mucosa of patients with bladder hypersensitivity but not idiopathic detrusor overactivity (IDO).

MATERIALS AND METHODS

Women with sensory urgency (SU), interstitial cystitis (IC), and IDO were investigated by videourodynamics and cystoscopy. Control biopsies were used for comparison. Biopsies were dissected into mucosa and muscle, and evaluated for TRPV1 mRNA expression using quantitative competitive RT-PCR (QC-RT-PCR).

RESULTS

TRPV1 mRNA from SU trigonal mucosa was significantly higher than control trigonal mucosa or SU bladder body mucosa. In contrast, in IDO patients, there was no difference between trigonal mucosa and body mucosa. In IC biopsies, RNA quality was substandard and unable to be used for analysis. The most striking finding was that TRPV1 mRNA expressed in SU trigonal mucosa was significantly inversely correlated with the bladder volume at first sensation of filling during cystometry. No such relationship was seen for IDO trigonal mucosa. No difference was seen in bladder body mucosa from any disease groups compared with age-matched control.

CONCLUSIONS

The symptoms of SU were associated with the increased expression of TRPV1 mRNA in the trigonal mucosa. No upregulation or regional differences of TRPV1 mRNA were seen in IDO patients. TRPV1 may play a role in SU and premature first bladder sensation on filling.

Chapitre C-l A - Traitement pharmacologique de l’hyperactivité détrusorienne neurologique : per os, en patch, en instillation endo-vésicale

Functional rehabilitation of neurourological patients always starts with patient education, retraining, and occupational therapy, possibly completed by medical treatments. In the light of a systematic review of the literature, the authors describe the various treatments that can be used orally and by intravesical instillation in these patients. They also describe treatments such as desmopressin or agents that increase sphincter pressure, which can sometimes be very useful to obtain stable clinical results that are satisfactory for the patient.

Neuromodulatory therapies in female pelvic medicine and reconstructive surgery: biological agents

In recent years, important improvements in the management of patients with neurogenic or non-neurogenic detrusor overactivity and urge incontinence have been brought about by the introduction of vanilloids and botulinum toxins in urology. In this review we introduce the new therapeutic options, provides basic information, and summarize the results experienced so far.

The puzzle of overactive bladder: controversies, inconsistencies, and insights

Overactive bladder (OAB) affects millions of individuals and may severely impair the quality of life of those affected. The contribution of human behavior to manifestations of this symptom complex remains poorly understood. Continued evolution of our understanding of the pathophysiology of OAB has identified contributory mechanisms, which in turn may open new therapeutic avenues. Recent improvements in drug delivery systems represent advances in the management of OAB. However, more complete symptom control with greater tolerability is desirable; this awaits the development of agents specific for newly emerging and as yet unidentified pathophysiologic pathways. Importantly, as understanding of outcomes assessment in OAB matures, refined assessments of disease severity, response to intervention, and patient preference should be possible.

The effect of cannabis on urge incontinence in patients with multiple sclerosis: a multicentre, randomised placebo-controlled trial (CAMS-LUTS)

OBJECTIVE

To test whether cannabinoids reduce urge incontinence episodes without affecting voiding in patients with multiple sclerosis. This was part of the multicentre trial of the Cannabinoids in Multiple Sclerosis (CAMS) study.

SUBJECTS AND METHODS

The CAMS study randomised 630 patients to receive oral administration of cannabis extract, Delta(9)-tetrahydrocannabinol (THC) or matched placebo. For this substudy subjects completed incontinence diaries.

RESULTS

All three groups showed a significant reduction, p<0.01, in adjusted episode rate (i.e. correcting for baseline imbalance) from baseline to the end of treatment: cannabis extract, 38%; THC, 33%; and placebo, 18%. Both active treatments showed significant effects over placebo (cannabis extract, p=0.005; THC, p=0.039).

CONCLUSION

The findings are suggestive of a clinical effect of cannabis on incontinence episodes in patients with MS. This is in contrast to the negative finding of the CAMS study, where no difference was seen in the primary outcome of spasticity.

Sacral neuromodulation in lower urinary tract dysfunction

Vesico-urethral dysfunction is a major problem in daily medical practice due to its psychological disturbances, its social costs and its high impact on quality of life. Recently, sacral neuromodulation, namely the electrical stimulation of the sacral nerves, appears to have become an alternative for radical bladder surgery particularly in cases of idiopathic bladder overactivity. The mechanism of action is only partially understood but it seems to involve a modulation in the spinal cord due to stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. It comprises the temporary application of neuromodulation as a diagnostic test to determine the best location for the implant and to control the integrity of the sacral root. If test stimulation is successful, a permanent device is implanted. This procedure is safe in experienced hands. So-called idiopathic bladder overactivity still the major indication for this technique. Patients not likely to benefit from the procedure were those with complete or almost complete spinal lesions, but incomplete spinal lesions seemed to be a potential indication. This technique is now also indicated in the case of idiopathic chronic retention and chronic pelvic pain syndrome. When selection is performed, more than three-quarters of the patients showed a clinically significant response with 50% or more reduction in the frequency of incontinent episodes, but the results vary according to the author's mode of evaluation. From the economic point of view, the initial investment in the device is amortized in the mid-term by savings related to lower urinary tract dysfunction. Finally, this technique requires an attentive follow-up and adjustments to the electric parameters so as to optimize the equilibrium between the neurological systems.

Overactive bladder

The overactive bladder is a common condition, which has significant effects on quality of life. The aetiology in most cases is unknown, and treatment outcomes have until recently been unsatisfactory. Management includes excluding pathology and implementing behavioural changes such as caffeine reduction, bladder and pelvic floor training, as well as antimuscarinic drug therapy. Compliance is often problematic, and this can be improved with some of the newer antimuscarinics with fewer side-effects, and a good therapist/patient relationship. In the majority of cases this 'treatment package' is successful, but in those where it is not, intravesical therapies have been introduced, e.g. neuromodulation, alternative drug therapies (e.g. vanilloids, botox) and surgery. With a better understanding of the aetiology and identification of risk factors better outcomes from treatment are likely.

Intravesical Vanilloids and Neurogenic Incontinence: Ten Years Experience

INTRODUCTION

In this study we critically review our '10-year' experience with intravesical vanilloids (capsaicin and resiniferatoxin) in the treatment of neurogenic incontinence, addressing the issue of their introduction into daily clinical practice.

MATERIALS AND METHODS

From July 1992 to June 2001, 54 patients suffering from detrusor hyperreflexia, due to spinal cord injuries, received intravesical instillation of capsaicin, and from January 1995 to June 2001, 47 patients received intravesical instillation of resiniferatoxin (RTX) in order to treat bladder dysfunction and symptoms. All patients presented detrusor hyperreflexia refractory to oral and/or intravesical oxibutynin and they displayed high-voiding pressure associated with frequent urine leakage. Capsaicin was used at a concentration of 10 mM; RTX was tested in two different concentrations: 10 nM and 10 microM. The outcome was considered according to simple parameters: (i) the number of patients who reported an improvement in clinical status (patient dry between clean intermittent catheterization) and urodynamic status (a bladder capacity 50% higher than pretreatment capacity, lasting more than 3 months after the instillation); (ii) the number of patients who continued intravesical therapy; (iii) the number of instillations they received; (iv) the length of the interval between 2 consecutive instillations, and (v) alternative therapies when vanilloids failed.

RESULTS

The topical intravesical instillation of capsaicin produced an improvement in symptoms and urodynamic parameters, in 29 patients (53.7%) after 3 months. In these 29 patients only 7 (24.13%) continued to received capsaicin in June 2001. The mean follow-up was 32.28 +/- 14.20 (range 8-52) months, the mean number of instillations was 6.14 +/- 2.54 (range 2-10) and the mean interval between the 2 consecutive instillations was 7.14 +/- 2.60 (range 4-12) months. The topical intravesical instillation of RTX produced an improvement in symptoms and urodynamic parameters in 73.33% of patients (a total of 45 patients) who received 10 microM. 18 of them (54.54%) continued to received RTX in June 2001. The mean follow-up was 27.88 +/- 10.95 (range 11-49) months, the mean number of instillations was 4.33 +/- 1.60 (range 2-8). The mean interval between 2 consecutive instillations was 9.61 +/- 2.99 (ranged 4-16) months.

CONCLUSION

The results obtained using RTX seem to be very promising with regard to efficacy and tolerance, particularly in comparison with capsaicin. Even if the number of patients who received capsaicin and RTX remains small, the intravesical vanilloid receptor agonist RTX could offer an attractive alternative to oral medications in the treatment of neurogenic incontinence.

Pharmacologic management of urinary incontinence in women

This article summarizes current thought regarding the efficacy of various types of drug therapy for incontinence in women, borrowing liberally from similar previous presentations. Space limitations for this chapter necessitate some simplification and condensation of these subjects. References have generally been chosen because of their informational or review content and not because of originality or initial publication on a particular subject.

After a decade of intravesical vanilloid therapy: still more questions than answers

Vanilloid sensitivity is a functional signature of a subset of unmyelinated fibres innervating the urinary bladder. The role that these nerves have in the physiological control of storage and voiding is unclear. However, after the bladder has been disconnected by spinal injury from the pontine micturition centre, vanilloid-sensitive fibres assume a central role in the reflex emptying of the bladder that occurs at low volumes. Intravesical vanilloid (capsaicin or resiniferatoxin) administration is beneficial in this disorder by "desensitising" these nerves. Resiniferatoxin is superior to capsaicin in terms of its tolerability profile. Investigators are moving rapidly to identify the mechanisms by which desensitisation to vanilloids occurs. Vanilloids induce lasting, but fully reversible, changes in gene expression, including downregulation of the vanilloid receptor subtype 1. It is hoped that application of gene chip technologies will address the global profile of vanilloid-induced changes in gene expression and their relative contribution to desensitisation. Drugs that target signalling mechanisms that bring about these changes in gene expression have obvious therapeutic potential.