Update on the treatment of overactive bladder

Bioelectronic medicine for the autonomic nervous system: clinical applications and perspectives

Bioelectronic medicine (BM) is an emerging new approach for developing novel neuromodulation therapies for pathologies that have been previously treated with pharmacological approaches. In this review, we will focus on the neuromodulation of autonomic nervous system (ANS) activity with implantable devices, a field of BM that has already demonstrated the ability to treat a variety of conditions, from inflammation to metabolic and cognitive disorders. Recent discoveries about immune responses to ANS stimulation are the laying foundation for a new field holding great potential for medical advancement and therapies and involving an increasing number of research groups around the world, with funding from international public agencies and private investors. Here, we summarize the current achievements and future perspectives for clinical applications of neural decoding and stimulation of the ANS. First, we present the main clinical results achieved so far by different BM approaches and discuss the challenges encountered in fully exploiting the potential of neuromodulatory strategies. Then, we present current preclinical studies aimed at overcoming the present limitations by looking for optimal anatomical targets, developing novel neural interface technology, and conceiving more efficient signal processing strategies. Finally, we explore the prospects for translating these advancements into clinical practice.

Overactive Bladder in Children

Overactive bladder (OAB) is clinically defined as the presence of urinary urgency and may be associated with diurnal urinary incontinence, frequency, and enuresis, and/or constipation. In children aged 5–10 years, the prevalence is 5–12%. Association with emotional disorders is widely described in the literature. Constipation is associated with voiding symptoms because of crosstalk between the gastrointestinal tract and the urinary tract. OAB is believed to be multifactorial. Correct functioning between the pontine micturition centre, the periaqueductal grey matter, anterior cingulate gyrus, and prefrontal cortex is important for correct voiding development and the process of maturation. Patients with OAB have greater anterior cingulate gyrus activity and deactivation of the pontine micturition centre urinary inhibition process, leading to a greater frequency of bladder repletion sensation. Urotherapy is the first treatment to be initiated and aims to change behavioural patterns inthese patients. Other treatment options are anticholinergics, with oxybutynin being the most widely studied, but also described is the use of tolterodine, darifenacin, and mirabegron. Alternative treatments, such as nerve stimulation in the parasacral or the posterior tibial area, have shown improvement of symptoms in comparative studies with conventional drug treatment, and, in refractory cases, botulinum toxin A is an option. In this article, we review the pathophysiology, associated conditions, and aspects related to diagnosis and treatment of OAB.

Clinical utility of neurostimulation devices in the treatment of overactive bladder: current perspectives

Objectives

This review describes the evidence from established and experimental therapies that use electrical nerve stimulation to treat lower urinary tract dysfunction.

Methods

Clinical studies on established treatments such as percutaneous posterior tibial nerve stimulation (P-PTNS), transcutaneous electrical nerve stimulation (TENS), sacral nerve stimulation (SNS) and sacral anterior root stimulation (SARS) are evaluated. In addition, clinical evidence from experimental therapies such as dorsal genital nerve (DGN) stimulation, pudendal nerve stimulation, magnetic nerve stimulation and ankle implants for tibial nerve stimulation are evaluated.

Results

SNS and P-PTNS have been investigated with high-quality studies that have shown proven efficacy for the treatment for overactive bladder (OAB). SARS has proven evidence-based efficacy in spinal cord patients and increases the quality of life. TENS seems inferior to other OAB treatments such as SNS and P-PTNS but is noninvasive and applicable for ambulant therapy. Results from studies on experimental therapies such as pudendal nerve stimulation seem promising but need larger study cohorts to prove efficacy.

Conclusion

Neurostimulation therapies have proven efficacy for bladder dysfunction in patients who are refractory to other therapies.

Significance

Refinement of neurostimulation therapies is possible. The aim should be to make the treatments less invasive, more durable and more effective for the treatment of lower urinary tract dysfunction.

Acetylcholinesterase Inhibitors and Drugs Acting on Muscarinic Receptors- Potential Crosstalk of Cholinergic Mechanisms During Pharmacological Treatment

BACKGROUND

Pharmaceuticals with targets in the cholinergic transmission have been used for decades and are still fundamental treatments in many diseases and conditions today. Both the transmission and the effects of the somatomotoric and the parasympathetic nervous systems may be targeted by such treatments. Irrespective of the knowledge that the effects of neuronal signalling in the nervous systems may include a number of different receptor subtypes of both the nicotinic and the muscarinic receptors, this complexity is generally overlooked when assessing the mechanisms of action of pharmaceuticals.

METHODS

We have search of bibliographic databases for peer-reviewed research literature focused on the cholinergic system. Also, we have taken advantage of our expertise in this field to deduce the conclusions of this study.

RESULTS

Presently, the life cycle of acetylcholine, muscarinic receptors and their effects are reviewed in the major organ systems of the body. Neuronal and non-neuronal sources of acetylcholine are elucidated. Examples of pharmaceuticals, in particular cholinesterase inhibitors, affecting these systems are discussed. The review focuses on salivary glands, the respiratory tract and the lower urinary tract, since the complexity of the interplay of different muscarinic receptor subtypes is of significance for physiological, pharmacological and toxicological effects in these organs.

CONCLUSION

Most pharmaceuticals targeting muscarinic receptors are employed at such large doses that no selectivity can be expected. However, some differences in the adverse effect profile of muscarinic antagonists may still be explained by the variation of expression of muscarinic receptor subtypes in different organs. However, a complex pattern of interactions between muscarinic receptor subtypes occurs and needs to be considered when searching for selective pharmaceuticals. In the development of new entities for the treatment of for instance pesticide intoxication, the muscarinic receptor selectivity needs to be considered. Reactivators generally have a muscarinic M2 receptor acting profile. Such a blockade may engrave the situation since it may enlarge the effect of the muscarinic M3 receptor effect. This may explain why respiratory arrest is the major cause for deaths by esterase blocking.

The combination of herbal medicine Weng-li-tong with Tolterodine may be better than Tolterodine alone in the treatment of overactive bladder in women: a randomized placebo-controlled prospective trial

BACKGROUND

To assess the efficacy and safety of the herbal medicine, Weng-li-tong (WLT) as monotherapy or combined with tolterodine in women with overactive bladder (OAB).

METHODS

A prospective, randomized, single-blind multi-center trial was performed which included 182 OAB patients treated with either placebo (n = 26), WLT (n = 52), tolterodine (n = 52) or WLT plus tolterodine (n = 52). The overactive bladder symptom score (OABSS) and micturition behavior were measured to evaluate treatment efficacy.

RESULTS

In total, 146 patients [placebo (n = 23), WLT (n = 39), tolterodine (n = 41) and WLT plus tolterodine (n = 43)] completed 8 weeks of treatment. Compared to those treated with placebo, patients in three intervention groups showed significant improvements in the OABSS, voiding frequency, average voided volume and urgency incontinence. WLT had a slower onset than tolterodine or combination therapy in reducing urgency incontinence. Compared with tolterodine, WLT had a weaker effect in improving OABSS (P = 0.022) and daily voiding frequency (P = 0.034). The combination therapy had better efficacy than WLT or tolterodine alone in improving the OABSS, voiding frequency and voided volume. No significant differences in the changes in quality of life scores were observed among the three intervention groups. Residual urine increased significantly in tolterodine group (P = 0.004), but not in combination group. WLT resulted in fewer adverse effects than tolterodine such as dry mouth (P = 0.002), weak stream (P = 0.002) and less residual urine (P < 0.001).

CONCLUSIONS

WLT could improve OAB symptoms in women, while it had slower onset and weaker efficacy but fewer adverse effects than tolterodine. The combination of WLT and tolterodine was more efficacious than tolterodine alone in improving OAB symptoms.

TRIAL REGISTRATION

Chinese Clinical Trial Registry [ ChiCTR-IPR-14005626 ]. Date of registration: 7 December 2014.

World Workshop on Oral Medicine VI: a systematic review of medication-induced salivary gland dysfunction

The aim of this paper was to perform a systematic review of the pathogenesis of medication-induced salivary gland dysfunction (MISGD). Review of the identified papers was based on the standards regarding the methodology for systematic reviews set forth by the World Workshop on Oral Medicine IV and the PRISMA statement. Eligible papers were assessed for both the degree and strength of relevance to the pathogenesis of MISGD as well as on the appropriateness of the study design and sample size. A total of 99 papers were retained for the final analysis. MISGD in human studies was generally reported as xerostomia (the sensation of oral dryness) without measurements of salivary secretion rate. Medications may act on the central nervous system (CNS) and/or at the neuroglandular junction on muscarinic, α-and β-adrenergic receptors and certain peptidergic receptors. The types of medications that were most commonly implicated for inducing salivary gland dysfunction were those acting on the nervous, cardiovascular, genitourinary, musculoskeletal, respiratory, and alimentary systems. Although many medications may affect the salivary flow rate and composition, most of the studies considered only xerostomia. Thus, further human studies are necessary to improve our understanding of the association between MISGD and the underlying pathophysiology.

Expert consensus on scientific evidence available on the use of botulinum toxin in overactive bladder

OBJECTIVES

Overactive bladder (OAB) is a pathology impairing patients' quality of life and with a high percentage of patients who are refractory to medication. In this paper, technical opinion of an «expert panel» is assessed in order to gain the most reliable professional consensus on scientific evidence available on the criteria of use of Onabotulinumtoxin A (OnabotA) in OAB.

MATERIAL AND METHODS

according to DELPHI method, 42 panelists answered a survey of 93 items divided into four strategic areas including clinical criteria and recommendations in order to improve, at different levels, the current approach to patients with OAB. The recent advances in the field, areas of controversy and their real application possibilities in the different areas of our health care system were taken into consideration.

RESULTS

Two rounds of the questionnaire were completed by all experts. In the first round, a criteria consensus was reached for 64 of 93 (68.8%) questions analyzed; in the second round the consensus reached was for 83 items evaluated (89.25%). An agreement among panelist was reached for: 1) definition, classification, detection and differential diagnosis; 2) medical treatment; 3) surgical treatment; 4) role of OnabotA in the treatment of OAB.

CONCLUSIONS

the consensus is broadly in line with the latest scientific evidence on OAB. The panelists believe that it is necessary to propose a change in the current definition of OAB and that it seems necessary to improve the screening tools too. Medical treatment of OAB must be tailored to each patient, staged and progressive. The use of OnabotA (Botox(®)) could imply therapeutic advantages with respect to other treatments, and positions itself as a safe and effective alternative to treat drug refractory OAB.

Randomized, double-blind placebo-controlled trial with Bryophyllum pinnatum versus placebo for the treatment of overactive bladder in postmenopausal women

INTRODUCTION

Overactive bladder syndrome (OAB) is a chronic disorder that often requires long-term treatment. There is a growing interest in new substances. In vitro experiments of Bryophyllum pinnatum (BP) on porcine bladder muscle have shown a muscle-relaxing effect. In this clinical trial we evaluated BP versus placebo regarding efficacy and safety.

MATERIALS AND METHODS

Prospective, double-blind randomized, placebo-controlled study with 20 patients (10 BP, 10 placebo); medication over 8 weeks; dosage 3×2 capsules BP 50% (350 mg)/day or placebo (lactose). Primary aim: reduction of the micturition frequency/24h. Secondary aim: change in quality of life, alterations of parameters in the bladder diary and adverse events (AE). Statistical analysis was performed with IBM SPSS Statistics 20. The groups were compared using Fisher's exact test and the Mann-Whitney test; the visits using the Wilcoxon signed ranks test.

RESULTS

Both groups did not differ significantly in demographical data. For the primary endpoint, a trend in the reduction of the micturition frequency/24h in the BP group was found: 9.5±2.2 before and 7.8±1.2 after BP versus 9.3±1.8 before and 9.1±1.6 after placebo, p=0.064. From visit 2 to visit 4, micturition frequency/24h improved in 8/10 patients in the BP group (p=0.037). In the placebo group, micturition frequency/24h improved in 5/9 patients (p=0.89). Improvement of the QoL did not differ between the two groups. The incidence of AE was similar in both groups, no SAE occurred.

CONCLUSION

The successful safety outcome and positive trend for efficacy permits BP to be further evaluated as a favorable treatment option for OAB.

Urgent-SQ implant in treatment of overactive bladder syndrome: 9-year follow-up study

AIMS

Electrical stimulation of the posterior tibial nerve (PTN) is an established therapy for the treatment of refractory overactive bladder syndrome (OAB). The Urgent-SQ™ is an implant that is surgically placed near the PTN and activated by an external pulse generator, allowing for "on demand" PTN stimulation, without the need for needle insertion. The current study presents results of a 9-year, open-label, follow-up of eight patients to address the long term safety and efficacy of the implant.

METHODS

In 2003, eight patients with refractory OAB received a Urgent-SQ™ implant and were systematically followed up for 1 year. After that, the follow up continued as open-label study. The seven patients who still had the implant were contacted after 9 years and evaluated with an interview, physical exam, ankle X-ray, voiding diaries, and completed questionnaires about adverse events, performance, efficacy, safety, and quality of life (validated iQoL).

RESULTS

Six of the seven patients still had sensory and loco-motor responses on stimulation at 9-year follow-up. Three of four patients who had a successful treatment response at 1 year, still use the device. The fourth patient restarted therapy. The implants are intact with no migration and/or displacement. All patients reported easy handling of the Urgent-SQ™. One patient reported sporadic spontaneous sensory responses. One patient reported occasional localized ankle discomfort.

CONCLUSIONS

After 9 years of clinical experience, we demonstrated that implant driven PTNS with the Urgent-SQ™ is a safe therapy for OAB. The implant has a long lifespan and is well tolerated by patients.

[Value of nerve growth factor levels in overactive bladder syndrome: alterations after botulinum toxin therapy]

OBJECTIVES

Several studies discussing the pathology of overactive bladder suggested changes in urinary proteins. The neurotrophin "nerve growth factor" (NGF) seems to be an important marker in overactive bladder syndrome (OAB). In this prospectively designed study we evaluated NGF blood levels (sNGF) initially and after injection of botulinum toxin type A (BTX-A) in the detrusor muscle in patients suffering from idiopathic OAB.

MATERIALS AND METHODS

Blood samples were obtained from 26 patients (66.5 years, 28-83) with idiopathic OAB. sNGF levels were measured before and 4 weeks after BTX-A treatment by enzyme-linked immunosorbent assay (ELISA). A group of 32 healthy persons with normal bladder function served as controls (41 years, 19-60). sNGF was evaluated in relation to clinical data and the severity of OAB (wet/dry).

RESULTS

Significantly higher sNGF levels were detected in patients with OAB compared to the control group (58.8 vs 2.0 pg/ml, p<0.005). Further, sNGF levels were elevated in patients with wet OAB compared to patients with dry OAB (85.0 vs 0.73 pg/ml, p<0.005). Patients > 60 years showed significantly higher sNGF levels (77.2 vs 8.9 pg/ml, p<0.05) compared to younger OAB patients. After BTX-A therapy sNGF levels decreased significantly compared to baseline (p<0.005).

CONCLUSION

NGF appears to play a decisive role in OAB. Its use as a biomarker in both the diagnostics and follow-up after therapy seems promising. To what extent sNGF can be useful as a biomarker or in therapy monitoring needs to be examined prospectively in a larger population.