Mechanisms involved in new therapies for overactive bladder

Antimicrobial Properties of Capsaicin: Available Data and Future Research Perspectives

Capsaicin is a phytochemical derived from plants of the genus Capsicum and subject of intensive phytochemical research due to its numerous physiological and therapeutical effects, including its important antimicrobial properties. Depending on the concentration and the strain of the bacterium, capsaicin can exert either bacteriostatic or even bactericidal effects against a wide range of both Gram-positive and Gram-negative bacteria, while in certain cases it can reduce their pathogenicity by a variety of mechanisms such as mitigating the release of toxins or inhibiting biofilm formation. Likewise, capsaicin has been shown to be effective against fungal pathogens, particularly Candida spp., where it once again interferes with biofilm formation. The parasites Toxoplasma gondi and Trypanosoma cruzi have been found to be susceptible to the action of this compound too while there are also viruses whose invasiveness is significantly dampened by it. Among the most encouraging findings are the prospects for future development, especially using new formulations and drug delivery mechanisms. Finally, the influence of capsaicin in somatostatin and substance P secretion and action, offers an interesting array of possibilities given that these physiologically secreted compounds modulate inflammation and immune response to a significant extent.

Biomedical and Antioxidant Potentialities in Chilli: Perspectives and Way Forward

Worldwide, since ages and nowadays, traditional medicine is well known, owing to its biodiversity, which immensely contributed to the advancement and development of complementary and alternative medicines. There is a wide range of spices, herbs, and trees known for their medicinal uses. Chilli peppers, a vegetable cum spice crop, are bestowed with natural bioactive compounds, flavonoids, capsaicinoids, phytochemicals, phytonutrients, and pharmacologically active compounds with potential health benefits. Such compounds manifest their functionality over solo-treatment by operating in synergy and consortium. Co-action of these compounds and nutrients make them potentially effective against coagulation, obesity, diabetes, inflammation, dreadful diseases, such as cancer, and microbial diseases, alongside having good anti-oxidants with scavenging ability to free radicals and oxygen. In recent times, capsaicinoids especially capsaicin can ameliorate important viral diseases, such as SARS-CoV-2. In addition, capsaicin provides an ability to chilli peppers to ramify as topical agents in pain-relief and also benefitting man as a potential effective anesthetic agent. Such phytochemicals involved not only make them useful and a much economical substitute to wonder/artificial drugs but can be exploited as obscene drugs for the production of novel stuffs. The responsibility of the TRPV1 receptor in association with capsaicin in mitigating chronic diseases has also been justified in this study. Nonetheless, medicinal studies pertaining to consumption of chilli peppers are limited and demand confirmation of the findings from animal studies. In this artifact, an effort has been made to address in an accessible format the nutritional and biomedical perspectives of chilli pepper, which could precisely upgrade and enrich our pharmaceutical industries towards human well-being.

DU Is Induced by Low Levels of Urinary ATP in a Rat Model of Partial Bladder Outlet Obstruction: The Incidence of Both Events Decreases after Deobstruction

Objectives. To investigate, in initial phases of bladder outlet obstruction (BOO), the urinary ATP levels, the incidence of detrusor underactivity (DU), and if they change after deobstruction. Methods. Adult female Wistar rats submitted to partial BOO (pBOO) and sham-obstruction were used. Cystometry was performed 3 or 15 days after pBOO and fluid was collected from the urethra for ATP determination. Bladders were harvested for morphological evaluation of the urothelium. DU was defined as the average of voiding contractions (VC) of sham-operated animals, with 3 SD at 15 days after the sham surgery. In another group of animals in which pBOO was relieved at 15 days and bladders were let to recover for 15 days, the incidence of DU and ATP levels were also accessed. The Kruskal–Wallis test was followed by Dunn’s multiple comparisons test, and Spearman’s correlation test was used. Results. DU was present in 13% and 67% of the bladders at 3 and 15 days after pBOO, respectively, and in 20% of the bladders at 15 days after deobstruction. ATP levels were significantly lower in DU/pBOO versus sham and non-DU/pBOO rats. A strong positive correlation between ATP levels and VC/min was obtained (r = 0.63). DU bladders had extensive areas in which umbrella cells appeared stretched, the width exceeding that presented by sham animals. Conclusions. Low urothelial ATP parallels with a high incidence of DU early after pBOO.

Association between overactive bladder and serum nerve growth factor concentrations in women with high-grade uterine prolapse

INTRODUCTION AND HYPOTHESIS

The association between overactive bladder (OAB) and uterine prolapse remains unclear. The extent of the role of serum nerve growth factor (NGF) levels in this relationship is also not known. Therefore, our study evaluated the association among OAB, high-grade uterine prolapse and serum NGF levels.

METHODS

A total of 90 patients participated in our study and were grouped as follows. Group I included patients with high-grade uterine prolapse and OAB, group II included patients with only high-grade uterine prolapse, and group III included healthy women without uterine prolapse or OAB. Serum NGF level analysis was performed in all groups.

RESULTS

Serum NGF levels varied greatly among the three groups, with significantly higher levels in group 1 than in groups 2 and 3 (p < 0.001). Serum NGF levels with a cutoff point of 120.49 pg/ml identified women with significant OAB symptoms to discriminate among groups with a sensitivity of 80%, specificity of 86.7%, positive predictive value of 75.0%, negative predictive value of 89.7% and positive likelihood ratio of 6.01 (p < 0.001).

CONCLUSIONS

Our study showed that NGF-related pathways may play an active role in the pathophysiology of OAB with high-grade uterine prolapse patients based on obstruction hypothesis.

Can Intradetrusor OnabotulinumtoxinA Injections Alter Heart Function in Patients with Cardiac Arrhythmia?

The prevalence of overactive bladder (OAB) increases with age and can be associated with other co-morbidities, such as cardiac arrhythmia. Unfortunately, commonly used anticholinergic drugs for OAB can affect the cardiovascular system, leading to tachycardia. However, there are no data, which consider the influence of intradetrusor onabotulinumtoxinA injections on heart function in idiopathic OAB patients. The aim of the present study was to evaluate the influence of intradetrusor onabotulinumtoxinA injections on electrocardiogram (ECG) parameters. Additionally, changes in ECG were analyzed in OAB patients without cardiac arrhythmia. Thirty-one patients with cardiac arrhythmia and 31 participants without irregular heart rate (HR) completed the study. ECG measurements were performed in supine positions 2 h before onabotulinumtoxinA injections, 1 h after treatment, and at 2 weeks of follow-up. At week 6, a phone-call survey was conducted to collect data about adverse events. OnabotulinumtoxinA injections were performed with rigid cystoscopy under local anesthesia. We did not observe any clinically significant changes in the analyzed ECG parameters between consecutive measurements. While a slight increase of HR was observed in patients without cardiac arrhythmia, it remained within normal range. Intravesical onabotulinumtoxinA injections are, hence, safe for female patients with cardiac arrhythmia and do not significantly influence changes in ECG.

Decreased inflammatory response in rat bladder after intravesical administration of capsaicin-loaded liposomes

The objective of this work was to study the reduction in the capsaicin toxicity by encapsulation in liposomes. Capsaicin was extracted from peppers and characterized with high performance liquid chromatography (HPLC). We determined the zeta potential, polydispersivity index (PdI) and vesicle size of liposomes. Wistar rats were submitted to intravesical instillation of liposomes (LIP), capsaicin (CAP) or liposomes with capsaicin (CAPLIP). After 24 hours, bladders were removed for histological analysis. Vesicle size ranged from 68 to 105 nm with PdI smaller than 0.2 and zeta potential around -30 mV. The vesicles maintained stability over the 14-day study. The histological analysis of the CAP group showed intense inflammation in almost all bladder layers, as well as ulcer formation. Conversely, the CAPLIP group showed a smooth inflammatory reaction and hyperemia. In conclusion, the liposomes effectively protected the bladder against the irritative action of capsaicin.

Intravesical resiniferatoxin for the treatment of storage lower urinary tract symptoms in patients with either interstitial cystitis or detrusor overactivity: a meta-analysis

Background

While Resin­iferatoxin (RTX) has been widely used for patients with storage lower urinary tract symptoms (LUTS), its clinical efficiency hasn't yet been well evaluated. A meta-analysis was performed to evaluate the exact roles of intravesical RTX for the treatment of storage LUTS in patients with either interstitial cystitis (IC) or detrusor overactivity (DO).

Methods

A meta-analysis of RTX treatment was performed through a comprehensive search of the literature. In total, 2,332 records were initially recruited, 1,907 from Elsevier, 207 from Medline and 218 from the Web of Science. No records were retrieved from the Embase or Cochrane Library. Seven trials with 355 patients were included and one trial was excluded because of the lack of extractable data. The analyses were all performed using RevMan 5.1 and MIX 2.0.

Results

Bladder pain was significantly reduced after RTX therapy in patients with either IC or DO. The average decrease of the visual an alogue pain scale was 0.42 after RTX treatment (p = 0.02). The maximum cystometric capacity (MCC) was significantly increased in patients with DO (MCC increase, 53.36 ml, p = 0.006) but not in those with IC (MCC increase, −19.1 ml, p = 0.35). No significant improvement in urinary frequency, nocturia, incontinence or the first involuntary detrusor contraction (FDC) was noted after RTX therapy (p = 0.06, p = 0.52, p = 0.19 and p = 0.41, respectively).

Conclusions

RTX could significantly reduce bladder pain in patients with either IC or DO, and increase MCC in patients with DO; however, no significant improvement was observed in frequency, nocturia, incontinence or FDC. Given the limitations in the small patient size and risk of bias in the included trials, great caution should be taken when intravesical RTX is used before a large, multicenter, well-designed random control trial with a long-term follow-up is carried out to further assess the clinical efficacy of RTX in in patients with storage LUTS.

An animal study to compare the degree of the suppressive effects on the afferent pathways of micturition between tamsulosin and sildenafil

Background

Tamsulosin, an α1-adrenoceptor antagonist, and sildenafil, a phosphodiesterase (PDE) inhibitor, are reported to improve lower urinary tract symptoms including overactive bladder (OAB). This study is aimed at investing the effects of tamsulosin and sildenafil and comparing the degree of the suppressive effects on the afferent pathways of micturition between them using an animal model of OAB, the spontaneously hypertensive rat (SHR).

Results

The cystometric parameters, the basal pressure and duration of bladder contraction, were significantly increased in the SHR group as compared with the Wistar-Kyoto (WKY) group. The intercontraction interval also significantly decreased in the SHR group. In the SHR-Tam 0.01 mg/kg group and the SHR-Sil 1 mg/kg group, however, the basal pressure and duration were significantly reduced and the intercontraction interval was significantly prolonged. Moreover, the degree of the expression of c-Fos and NGF was significantly higher in the SHR group as compared with the WKY group. But it was significantly reduced in the SHR-Tam 0.01 mg/kg group and the SHR-Sil 1 mg/kg group. Furthermore, tamsulosin had a higher degree of effect as compared with sildenafil.

Conclusions

In conclusion, α1-adrenergic receptor antagonists and PDE-5 inhibitors may have an effect in improving the voiding functions through an inhibition of the neuronal activity in the afferent pathways of micturition.

Alteration in TRPV1 and Muscarinic (M3) receptor expression and function in idiopathic overactive bladder urothelial cells

AIM

To examine function of both cholinergic (muscarinic) and TRPV1 receptors in human bladder urothelial (HBUC) from non-neurogenic overactive bladder (OAB) patients as compared to control subjects.

METHODS

Primary HBUC cultures were derived from cystoscopic biopsies from OAB and control subjects. Muscarinic and TRPV1 function was assessed by acetylcholine (5 μm) or capsaicin (0.5 μm) evoked ATP release, measured by luciferase assay. Overall, expression of TRPV1 and muscarinic M3 receptors in bladder urothelial cells was accomplished using western immunoblotting.

RESULTS

Our findings revealed that the response to acetylcholine in OAB HBUC cultures (which was blocked by the nonselective muscarinic antagonist, atropine methyl nitrate or AMN) was not significantly different than from controls. The acetylcholine M3 receptor was slightly decreased as compared to control. In contrast, OAB HBUC cultures exhibited a capsaicin hypersensitivity and augmented release of ATP (3.2 fold higher), which was blocked by the antagonist capsazepine. The increase in capsaicin sensitivity correlated with increased urothelial TRPV1 expression.

CONCLUSION

Though characterized in a small number of subjects, augmented release of urothelial-derived transmitters such as ATP could 'amplify' signalling between and within urothelial cells and nearby afferent nerves.

[Vesical urothelium and new concepts]

Vesical urothelium was long considered to simply be a protection barrier, which passively separates the urinary content from the underlying smooth muscle and the blood stream. Recent observations, though, have pointed out that vesical urothelium cells have clear active and sensory functions, in response to various physical and chemical stimuli. Among these characteristics are the expression of several neurotransmitters and receptors: Acetylcholine, Nitric Oxide, VIP, CGRP, NKA, SP and cholinergic, vanilloid, purinergic, and tachykinin receptors. Urothelium-produced neurotransmitters are likely supposed to act through a receptor stimulation of the afferent nerve fibers within the sub-urothelial spaces. Sub-urothelial myofibroblasts are considered to play a mediation role between urothelium-produced neurotransmitters and the underlying receptors. According to these observations, a pharmacologic modulation, directly affecting the urothelium, can be hypothesized.

Characterization of a reproducible gastric pain model using oral capsaicin titration in healthy volunteers

BACKGROUND

  Sensory sensitization is one of the main pathophysiological hypotheses in functional gastrointestinal disorders (FGIDs). As sensitization may affect various sensory modalities, we aimed to develop a reproducible gastric pain model utilizing polymodal pathways for use in functional and other pain disorders.

METHODS

In this double-blind, cross-over study 42 healthy subjects swallowed one capsule containing either capsaicin 0.5mg or nocebo every 15min until moderate pain (intensity >30 on 100mm visual analogue scale) was attained for at least 5min. Pain was rated every minute. Capsaicin titration was repeated thrice for reliability calculation.

KEY RESULTS

Moderate pain in the upper abdomen was successfully achieved in 38 of 42 subjects (90%) with capsaicin titration and in one of 42 (2%) with nocebo. The median dosage required to induce moderate pain for at least 5min was two capsules (interquartile range 1-3) and the median gastric pain intensity was 47 (41-53). The median duration of moderate pain was 8min (5-12). Moderate pain was successfully reproduced with capsaicin in all subjects on study days 2 and 3, with an excellent Cronbach reliability coefficient of >0.8.

CONCLUSIONS & INFERENCES

Standardized gastric pain can be conveniently achieved in a majority of healthy subjects using a simple oral capsaicin titration, with minimal adverse events. The between-test reproducibility is high and nocebo responses are negligible. This technique stimulating a multimodal physiological pathway will be useful in the investigation of sensory changes in FGIDs, including functional dyspepsia.

Increased transient receptor potential vanilloid type 1 (TRPV1) signaling in idiopathic overactive bladder urothelial cells

AIMS

To measure transient receptor potential vanilloid type 1 (TRPV1) signaling in human bladder urothelial cells (BUC) from non-neurogenic overactive bladder (OAB) patients and control subjects (NB) BUC.

MATERIALS AND METHODS

Primary BUC cell cultures were derived from cystoscopic biopsies from two OAB and two NB subjects. TRPV1 expression was detected by immunofluorescence, PCR and Western blot staining. TRPV1 function was assessed by capsaicin (CAP, 6 µM)-evoked intracellular calcium ([Ca(2+)](i)) changes measured by microfluorimetry imaging. CAP evoked changes in inward and outward currents were recorded electrophysiologically using excised outside-out patches and whole cell configurations using various protocols.

RESULTS

OAB BUC had significantly increased expression of TRPV1 compared to NB BUC on Western blot. CAP evoked significantly higher maximal [Ca(2+)](i) change over baseline in OAB (84.71 ± 8.96%) compared to NB BUC (60.32 ± 7.93%) (P < 0.05). CAP induced significantly greater percent change in single channel open probability (205.94 ± 20.53% OAB vs. 141.26 ± 16.53% NB, P < 0.05) and normalized inward currents (13.54 ± 1.6 4 pA/pF OAB vs. 8.28 ± 0.89 pA/pF NB, P < 0.05). CAP caused significantly higher percent increase from baseline of whole cell outward currents in OAB (177.12 ± 44.46%) compared to NB BUC (135.98 ± 44.28%) (P < 0.05). Similarly thermal stimulus (45°C solution) evoked significantly higher percent increase in whole cell outward currents in OAB (183.93 ± 14.07%) compared to NB (145.61 ± 10.12%) BUC (P < 0.05). These responses were blocked by 10 µM capsazepine (CPZ), a TRPV1 antagonist.

CONCLUSIONS

Because only a few subjects were studied, augmented TRPV1 signaling cannot be generalized to all OAB subjects. However, the findings are consistent with the hypothesis that BUC are involved in sensory signaling.

Neurophysiology of the lower urinary tract

The lower urinary tract (LUT) has two functions: (1) the storage of waste products in the form of urine and (2) the elimination of those wastes through micturition. The LUT operates in a simple "on-off" fashion, either storing urine or releasing it during voiding. While this activity may seem simple, micturition is controlled by a complex set of peripheral neurons that are, in turn, coordinated by cell groups in the spinal cord, brainstem, and brain. When this careful coordination is interrupted, the control of the bladder is lost, resulting in incontinence or retention of urine. The purpose of this chapter is to review how the neural systems coordinating the activity of the lower urinary tract form neural circuits that are responsible for either maintaining continence (the storage reflex) or inducing micturition (the voiding reflex). We will also discuss the brain centers that enable higher organisms to voluntarily choose the time and place for voiding. Finally, we will discuss how defects in the pathways controlling micturition can lead to urinary incontinence and which treatments may normalize LUT function.

The ERK 1 and 2 pathway in the nervous system: from basic aspects to possible clinical applications in pain and visceral dysfunction

The extracellular signal-regulated kinases 1 and 2 (ERK) cascade, member of the mitogen-activated protein kinases superfamily of signalling pathways, is one of the best characterized pathways as many protein interactions and phosphorylation events have been systematically studied. Traditionally, ERK are associated with the regulation of proliferation and differentiation as well as survival of various cell types. Their activity is controlled by phosphorylation on specific aminoacidic residues, which is induced by a variety of external cues, including growth-promoting factors.

In the nervous system, ERK phosphorylation is induced by binding of neurotrophins to their specific tyrosine kinase receptors or by neuronal activity leading to glutamate release and binding to its ionotropic and metabotropic receptors. Some studies have provided evidence of its importance in neuroplastic events. In particular, ERK phosphorylation in the spinal cord was shown to be nociceptive-specific and its upregulation, occurring in cases of chronic inflammatory and neuropathic pain, seems to be of the utmost importance to behavioural changes observed in those conditions. In fact, experiments using specific inhibitors of ERK phosphorylation have proved that ERK directly contributes to allodynia and hyperalgesia caused by spinal cord injury or chronic pain. Additionally, spinal ERK phosphorylation regulates the micturition reflex in experimental models of bladder inflammation and chronic spinal cord transection.

In this review we will address the main findings that suggest that ERK might be a future therapeutic target to treat pain and other complications arising from chronic pain or neuronal injury.

Homozygous TRPV1 315C influences the susceptibility to functional dyspepsia

OBJECTIVES

Capsaicin/vanilloid (transient receptor potential vanilloid 1, (TRPV1) receptor has been shown to be expressed in gastrointestinal tract and play a role as a member of sensory ion channel superfamily. The G315C polymorphism affects the TRPV1 gene and alters its protein level. We aimed to investigate the effect of TRPV1 G315C polymorphism on functional dyspepsia (FD) in a Japanese population.

METHODS

TRPV1 G315C polymorphism was genotyped in 98 subjects with no upper abdominal symptoms and 109 patients with FD. Severity of 7 upper gastrointestinal symptoms was assessed during cold water, and cold carbonated water drinking for randomly selected 20 healthy subjects.

RESULTS

We found a significant inverse association between TRPV1 315CC genotype and FD [CC vs. others; odds ratio (OR)=0.40, 95% confidence interval (CI)=0.38-0.82]. We also found that the same genotype held a lower risk of both epigastric pain syndrome (OR=0.25, 95% CI=0.09-0.73), postprandial syndrome (OR=0.27, 95% CI=0.07-0.96) according to Rome III, and Helicobacter pylori positive FD (OR=0.28, 95% CI=0.10-0.79). The evolution of symptom severity scale of 7 total symptoms (P=0.004), and heavy feeling in stomach (P=0.02) during cold carbonated water drinking were significantly lower among 315CC genotypes compared with others.

CONCLUSIONS

Homozygous TRPV1 315C influences the susceptibility to FD through altering the upper gastrointestinal sensation.

Vanilloid receptor TRPV1-mediated phosphorylation of ERK in murine adjuvant arthritis

OBJECTIVE

The vanilloid receptor transient receptor potential vanilloid 1 (TRPV1), expressed by sensory neurons that innervate joints, is implicated in arthritis but the mechanisms are not fully understood. One possibility is that downstream effects of activation of TRPV1 are mediated by the extracellularly-regulated kinase (ERK). ERK is phosphorylated (p-ERK) in sensory neurons in response to noxious stimuli and its inhibition has been found to be antinociceptive in several pain models. We here wanted to ascertain whether TRPV1 may contribute to the pain hypersensitivity and inflammation of arthritis via an ERK-mediated pathway.

METHODS

We used a model of adjuvant-induced arthritis (AIA) of the ankle and investigated the changes in expression of p-ERK in sensory afferent neurons in dorsal root ganglia (DRG) and spinal dorsal horn of TRPV1-knockout (KO) mice, compared to wild-type (WT) mice of the same genetic background, using multiple immunofluorescence.

RESULTS

Two to three weeks after inducing AIA in mice, the number of neurons in DRG and spinal cord that expressed p-ERK was significantly higher on the side of AIA than on the contralateral, vehicle-injected side. The fraction of p-ERK-positive neurons in the DRG that also expressed TRPV1 was increased, indicating that activation of ERK occurred preferentially in TRPV1-positive neurons. Moreover, TRPV1-KO mice had reduced activation of ERK in sensory neurons, compared to WT mice. These changes in expression of p-ERK correlated with changes in pain behavior and joint histopathology: TRPV1-KO mice had reduced nociceptive behavior and severity of arthritis, compared to WT mice.

CONCLUSION

Our results support the idea that activation of ERK in primary afferent neurons is mediated, at least in part, by TRPV1. In the absence of TRPV1, the signs of arthralgia and histopathology in the mouse model of AIA are reduced. We conclude that TRPV1, expressed by neurons in the articular afferent pathway, contributes to the pathogenesis of arthritis via an ERK-mediated pathway.

Modulation of bladder myofibroblast activity: implications for bladder function

Bladder suburothelial myofibroblasts may modulate both sensory responses from the bladder wall and spontaneous activity. This study aimed to characterize further these cells in their response to exogenous agents implicated in mediating the above activity. Detrusor strips, with or without mucosa, and isolated suburothelial myofibroblasts were prepared from guinea pig bladders. Isometric tension, intracellular Ca²⁺, and membrane current were recorded. Cell pairs were formed by pushing two cells together. Tension, intracellular Ca²⁺, and membrane potential were also recorded from bladder sheets using normal or spinal cord-transected (SCT) rats. Spontaneous contractions were greater in detrusor strips with an intact mucosa and were augmented by 10 μM UTP. ATP, UTP, or reduced extracellular pH elicited Ca²⁺ transients and inward currents (E_rev −30 mV) in isolated cells. Capsaicin (5–30 μM) reduced membrane current (37 ± 12% of control) with minor effects on Ca²⁺ transients: sodium nitroprusside reduced membrane currents (40 ± 21% of control). Cell pair formation, without an increase in cell capacitance, augmented ATP and pH responses (180 ± 58% of control) and reduced the threshold to ATP and acidosis. Glivec (20–50 μM) reversibly blocked the augmentation and also reduced spontaneous activity in bladder sheets from SCT, but not normal, rats. Glivec also disrupted the spread of Ca²⁺ waves in SCT sheets, generating patterns similar to normal bladders. Suburothelial myofibroblasts respond to exogenous agents implicated in modulating bladder sensory responses; responses augmented by physical intercellular contact. The action of glivec and its selective suppression of spontaneous activity in SCT rats identifies a possible pathway to attenuate bladder overactivity.

Extracellular microenvironment and cytokine profile of the ureterovesical junction in children with vesicoureteral reflux

PURPOSE

Vesicoureteral reflux is caused by a defective valve mechanism of the ureterovesical junction. Previous studies have revealed structural and metabolic changes in the intravesical ureter, impairing its contractile properties. Smooth musculature and nerves are replaced by collagen, while matrix degrading enzymes are over expressed. We investigated the presence of regulating cytokines and the extracellular matrix composition to elucidate further the pathophysiology of vesicoureteral reflux.

MATERIALS AND METHODS

Ureteral endings were obtained from 28 children during antireflux surgery, and 14 age matched autopsy specimens served as controls. Routine histological sections were immunostained for insulin-like growth factor-1, nerve growth factor, transforming growth factor-beta1, tumor necrosis factor-alpha and vascular endothelial growth factor. Smooth muscle staining was supplemented by tenascin C, tetranectin and fibronectin detection. Staining patterns were investigated using computer assisted, high power field magnification analyses.

RESULTS

Tumor necrosis factor-alpha and transforming growth factor-beta1 were significantly more abundant in vesicoureteral reflux samples, whereas insulin-like growth factor-1, nerve growth factor and vascular endothelial growth factor were more prevalent in healthy controls. Fibronectin was intensely expressed in refluxing ureters, while it was scarce in healthy children. Tenascin C was notable within the urothelium of both groups. Only vesicoureteral reflux samples displayed tenascin C in the musculature and connective tissue. Tetranectin staining was only detected in vesicoureteral reflux.

CONCLUSIONS

Several cytokines are differentially expressed in primary refluxing ureters, indicating an ongoing tissue remodeling process in the ureterovesical junction region. Additionally, the smooth muscle coat is widely lacking, while extracellular matrix proteins typical for tissue shrinkage and reorganization are over expressed. These alterations are likely to contribute to the malfunctioning active ureteral valve mechanism in primary vesicoureteral reflux.

Capsaicin (TRPV1 Agonist) therapy for pain relief: farewell or revival?

OBJECTIVE

In this review, we explain our current understanding of the molecular basis for pain relief by capsaicin and other transient receptor potential vanilloid subfamily, member 1 (TRPV1) agonists. We summarize disease-related changes in TRPV1 expression and its implications for therapy and potential adverse effects. Last, we provide an overview of the current clinical uses of topical and injectable TRPV1 agonist preparations in both oncologic and nononcologic populations.

METHOD

Search of MEDLINE and other databases.

RESULTS

The capsaicin receptor TRPV1 is a polymodal nociceptor exhibiting a dynamic threshold of activation that could be lowered under inflammatory conditions. Consistent with this model, TRPV1 knock-out mice are devoid of post-inflammatory thermal hyperalgesia. TRPV1 desensitization of primary sensory neurons is a powerful approach to relieve symptoms of nociceptive behavior in animal models of chronic pain. However, over-the-counter capsaicin creams have shown moderate to poor analgesic efficacy. This is in part related to low dose, poor skin absorption, and compliance factors. Recently developed site-specific capsaicin therapy with high-dose patches and injectable preparations seem to be safe and reportedly provide long-lasting analgesia with rapid onset.

CONCLUSIONS

We argue that TRPV1 agonists and antagonists are not mutually exclusive but rather complimentary pharmacologic approaches for pain relief and we predict a "revival" for capsaicin and other TRPV1 agonists in the clinical management of pain associated with inflammation, metabolic imbalances (eg, diabetes), infections (HIV), and cancer, despite the current focus of the pharmaceutical industry on TRPV1 antagonists.

ThermoTRP channels in nociceptors: taking a lead from capsaicin receptor TRPV1

Nociceptors with peripheral and central projections express temperature sensitive transient receptor potential (TRP) ion channels, also called thermoTRP's. Chemosensitivity of thermoTRP's to certain natural compounds eliciting pain or exhibiting thermal properties has proven to be a good tool in characterizing these receptors. Capsaicin, a pungent chemical in hot peppers, has assisted in the cloning of the first thermoTRP, TRPV1. This discovery initiated the search for other receptors encoding the response to a wide range of temperatures encountered by the body. Of these, TRPV1 and TRPV2 encode unique modalities of thermal pain when exposed to noxious heat. The ability of TRPA1 to encode noxious cold is presently being debated. The role of TRPV1 in peripheral inflammatory pain and central sensitization during chronic pain is well known. In addition to endogenous agonists, a wide variety of chemical agonists and antagonists have been discovered to activate and inhibit TRPV1. Efforts are underway to determine conditions under which agonist-mediated desensitization of TRPV1 or inhibition by antagonists can produce analgesia. Also, identification of specific second messenger molecules that regulate phosphorylation of TRPV1 has been the focus of intense research, to exploit a broader approach to pain treatment. The search for a role of TRPV2 in pain remains dormant due to the lack of suitable experimental models. However, progress into TRPA1's role in pain has received much attention recently. Another thermoTRP, TRPM8, encoding for the cool sensation and also expressed in nociceptors, has recently been shown to reduce pain via a central mechanism, thus opening a novel strategy for achieving analgesia. The role of other thermoTRP's (TRPV3 and TRPV4) encoding for detection of warm temperatures and expressed in nociceptors cannot be excluded. This review will discuss current knowledge on the role of nociceptor thermoTRPs in pain and therapy and describes the activator and inhibitor molecules known to interact with them and modulate their activity.

Therapeutic effects of the putative P2X3/P2X2/3 antagonist A-317491 on cyclophosphamide-induced cystitis in rats

It is suggested that ATP and purinergic P2X receptors are involved in overactive bladder. In this study, we investigated the effect of the recently developed P2X3 and P2X2/3 receptor antagonist A-317491 on cyclophosphamide (CYP)-induced cystitis to determine whether a P2X receptor antagonist could be beneficial for the treatment of bladder overactivity induced by CYP. Female Sprague-Dawley (SD) rats were given 150 mg/kg CYP (i.p.). When the micturition activity was observed for 24 h in a conscious and unrestrained condition, CYP-treated rats exhibited increased urinary frequency. Two days after CYP injection, cystometry was performed in conscious rats, in which the bladder was continuously infused with saline (5 ml/h). In CYP-treated rats, non-voiding contractions were interposed between micturitions, suggestive of hyper-reflexia. Intravenous administration of A-317491 (20 or 50 mg/kg) or pyridoxal phosphate-6-azo (benzene-2,4-disulfonic acid) tetrasodium (PPADS; a nonselective purinergic receptor antagonist, 10 mg/kg) prolonged the interval of voiding contraction and reduced the non-voiding contractions. On the other hand, oxybutynin (1 mg/kg), a muscarinic receptor antagonist, did not affect the frequency of non-voiding or voiding contractions in CYP-treated rats. A-317491 at the higher dose decreased the amplitude of voiding contractions, but increased the micturition volume. The residual urine in the bladder increased after treatment with CYP; A-317491 and PPADS reduced this, whereas oxybutynin had no effect. These data suggest that A-317491 is effective at improving the signs of CYP-induced cystitis and that the P2X3 or P2X2/3 receptor pathway is involved in bladder overactivity observed during CYP-induced cystitis.

Capsaicin causes protein synthesis inhibition and microtubule disassembly through TRPV1 activities both on the plasma membrane and intracellular membranes

TRPV1 is a non-selective cationic channel that is activated by capsaicin, acidic pH and thermal stimuli. Sustained TRPV1 channel activation causes severe cytotoxicity that leads to cell death. In this study, we investigated the mechanisms of capsaicin-induced cytotoxicity in HEK293 cells stably expressing TRPV1 with a focus on protein synthesis regulation and cytoskeleton reorganization. Capsaicin inhibited protein synthesis in TRPV1-expressing HEK cells with an IC(50) of 15.6nM and depolymerized microtubules within 10min after exposure. These effects were completely blocked by pretreatment of cells with the TRPV1 antagonist A-425619, both in the presence and absence of extracellular calcium. Protein synthesis inhibition induced by capsaicin was not a result of eIF2alpha hyperphosphorylation, but rather closely correlated with cytosolic calcium elevation caused by calcium flux through cell surface and intracellular TRPV1, and/or ER calcium depletion through intracellular TRPV1. Microtubule dependent cell process shrinkage may serve as a mechanism for rapid alteration of the neurotransmission network upon TRPV1 activation. Taken together, the present studies demonstrate that intracellular pool of TRPV1 plays an important role in regulating cell morphology and viability upon receptor activation.

Multiple Intravesical Instillations of Low-Dose Resiniferatoxin in the Treatment of Refractory Interstitial Cystitis

BACKGROUND

Current medications used in the treatment of interstitial cystitis (IC) have limited efficacy. This prospective study investigated the efficacy of multiple intravesical instillations of resiniferatoxin (RTX) at the concentration of 10 nM.

METHODS

Patients with proven IC previously treated with traditional medications for more than 6 months without clinical benefit were enrolled. They were excluded if bladder outlet obstruction or urinary tract infection was present. Intravesical instillation of low-dose RTX (10 nM) once weekly for 4 weeks was performed at the outpatient department. International Prostate Symptom Score (IPSS), 5-Point Pain Scale, and Quality of Life Index (QOL Index) were recorded. A videourodynamic study was done at baseline and 3 months after treatment.

RESULTS

The therapeutic results and urodynamic parameters were compared between baseline and 3 months. Thirteen patients, including 10 women and 3 men, were enrolled in this study. The mean duration of IC symptoms was 4.4 +/- 2.5 years. The mean duration of active treatment was 15.3 +/- 8.6 months. One female patient dropped out due to severe bladder pain after RTX instillation. Among the 12 patients who completed the study treatment, subjective assessment revealed that 2 had an excellent therapeutic result, 5 had an improved result and 5 remained unchanged from baseline. The overall satisfactory rate was 58.3%. IPSS, 5-Point Pain Scale, and QOL Index were significantly decreased after RTX treatment. There was no significant increase in mean functional bladder capacity or change in urodynamic parameters. No serious adverse event occurred after RTX treatment.

CONCLUSIONS

This study suggests that multiple intravesical instillations of RTX at the concentration of 10 nM are effective in relieving lower urinary tract symptoms in patients with refractory IC. The treatment is tolerable and suitable for use on an outpatient clinic basis.

LUTS treatment: Future treatment options

Lower urinary tract symptoms (LUTS) are commonly divided into storage, voiding, and postmicturition symptoms, and may occur in both men and women. Male LUTS have historically been linked to benign prostatic hyperplasia (BPH), but are not necessarily prostate related. The focus of treatment for LUTS has thus shifted from the prostate to the bladder and other extraprostatic sites. LUTS include symptoms of the overactive bladder (OAB), which are often associated with detrusor overactivity. Treatment for LUTS suggestive of BPH has traditionally involved the use of alpha(1)-adrenoceptor (AR) antagonists; 5alpha-reductase inhibitors; and phytotherapy-however, several new therapeutic principles have shown promise. Selective beta(3)-adrenoceptor agonists and antimuscarinics are potentially useful agents for treating LUTS, particularly for storage symptoms secondary to outflow obstruction. Other agents of potential or actual importance are antagonists of P2X(3) receptors, botulinum toxin type A, endothelin (ET)-converting enzyme inhibitors, and drugs acting at vanilloid, angiotensin, and vitamin D(3) receptor sites. Drugs interfering with the nitric oxide/cGMP-cAMP pathway, Rho-kinase and COX inhibitors, as well as drugs targeting receptors and mechanisms within the CNS, are also of interest and deserving of further study for the treatment of LUTS.

Local drug delivery to bladder using technology innovations

Local delivery of drugs directly into the bladder by way of a urethral catheter is a clever approach to optimize drug delivery to the disease site while reducing systemic bioavailability. Pharmacotherapy by this route is referred to as intravesical delivery. In recent years, intravesical delivery has been used in combination with and oral regimen of drugs or as second-line treatment for neurogenic bladder and detrusor overactivity. Negligible absorption of instilled drugs into the systemic circulation explains the near-minimal adverse toxicity reported with this form of therapy. The authors discuss shortcomings of the current options available for intravesical delivery and provide a broad overview of the latest advances through technology innovation to overcome these drawbacks.

Recent advances in intravesical drug/gene delivery

Targeting of drugs administered systemically relies on the higher affinity of ligands for specific receptors to obtain selectivity in drug response. However, achieving the same goal inside the bladder is much easier with an intelligent pharmaceutical approach that restricts drug effects by exploiting the pelvic anatomical architecture of the human body. This regional therapy involves placement of drugs directly into the bladder through a urethral catheter. It is obvious that drug administration by this route holds advantage in chemotherapy of superficial bladder cancer, and it has now become the most widely used treatment modality for this ailment. In recent years, the intravesical route has also been exploited either as an adjunct to an oral regimen or as a second-line treatment for neurogenic bladder. (Lamm, D. L.; Griffith, J. G. Semin. Urol. 1992, 10, 39-44. Igawa, Y.; Satoh, T.; Mizusawa, H.; Seki, S.; Kato, H.; Ishizuka, O.; Nishizawa, O. BJU Int. 2003, 91, 637-641.) Instillation of DNA via this route using different vectors has been able to restrict the transgene expression in organs other than bladder. The present review article will discuss the shortcomings of the current options available for intravesical drug delivery (IDD) and lay a perspective for future developments in this field.

Intravesical antisense therapy for cystitis using TAT-peptide nucleic acid conjugates

The present study investigated the potential of intravesical instillation for localized reduction of NGF (nerve growth factor) expression in the urinary bladder. Overexpression of NGF has been linked to the pathogenesis of interstitial cystitis (IC). A minimum free energy algorithm was used to predict suitable regions in mRNA of rat betaNGF, which can be targeted for an antisense approach. The candidate antisense oligos were evaluated for their ability to reduce NGF expression in vitro by cotransfecting HEK293 cells with NGF cDNA. A single oligonucleotide ODN sequence was chosen for testing in an acute cystitis model in rat induced by cyclophosphamide. Overexpression of NGF is known to mediate inflammation of bladder in this model. For improved stability, antisense ODN was replaced with antisense peptide nucleic acid (PNA) and its penetration into bladder was facilitated by tethering TAT peptide sequence. Rat bladders were instilled with either antisense or its scrambled control prior to cystitis induction. Cystometrograms performed on rats under urethane anaesthesia exhibited bladder contraction frequency that was significantly decreased in the antisense treated rats than rats treated with the control. NGF immunoreactivity was also decreased in the urothelium of the antisense treated bladders. Our findings demonstrate the feasibility of using TAT-PNA conjugates for intravesical antisense therapy.

TRPV1: a therapeutic target for novel analgesic drugs?

The vanilloid receptor TRPV1 is now recognized as a molecular integrator of painful stimuli ranging from noxious heat to endovanilloids in inflammation. Pharmacological blockade of TRPV1 represents a new strategy in pain relief. TRPV1 antagonists are expected to prevent pain by silencing receptors where pain is generated rather than stopping the propagation of pain, as most-traditional pain killers do. This hypothesis has already being tested in the clinic by administering small molecule TRPV1 antagonists (e.g. GlaxoSmithKline SB-705498) for migraine and dental pain. Paradoxically, in some murine models of chronic pain, TRPV1-deficient mice exhibit more pain-related behavior than their wild-type littermates, indicating that the understanding of TRPV1 in pain is still incomplete. Moreover, there is mounting evidence to suggest the existence of functional TRPV1 both in the brain and in various non-neuronal tissues. The biological role of these receptors remains elusive, but their tissue distribution clearly indicates that they are involved in many more functions than just pain perception. Here, we review the potential therapeutic indications and adverse effects of TRPV1 antagonists.

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 overactive bladder: review of current pharmacotherapy in adults. Part 2: treatment options in cases refractory to anticholinergics

In the first part of this review the potential pathophysiological factors involved in the overactive bladder were outlined, and the wide range of first-line anticholinergic pharmacotherapies available for such patients were reviewed. The second part will focus on the intravesical instillation of resiniferatoxin and injections of botulinum toxin into the bladder to treat overactive bladder and detrusor overactivity. Resiniferatoxin has been shown to increase bladder capacity and improve incontinence in patients with neurogenic and non-neurogenic detrusor overactivity. Botulinum toxin has successfully been used to treat neurogenic and idiopathic detrusor overactivity, with improvements observed in bladder capacity, decreases in detrusor pressures on filling and voiding, and increased volumes at first contraction. Further validation is required for both treatments, in the form of large randomised controlled trials, before their use can be considered routine, with particular focus on dosing required.

Botulinum-A toxin injections into the detrusor muscle decrease nerve growth factor bladder tissue levels in patients with neurogenic detrusor overactivity

PURPOSE

We investigated the effects of BTX-A on visceral afferent nerve transmission by measuring bladder tissue NGF levels in patients with neurogenic detrusor overactivity before and after intravesical treatment with BTX-A. We also compared the bladder tissue NGF content with clinical and urodynamic data.

MATERIALS AND METHODS

A total of 23 patients underwent clinical evaluation and urodynamics with detection of the UDC threshold, maximum pressure and maximum cystometric capacity before, and at the 1 and 3-month followups. Endoscopic bladder wall biopsies were also obtained at the same time points. NGF levels were measured in tissue homogenate by enzyme-linked immunosorbent assay (Promega, Madison, Wisconsin).

RESULTS

At 1 and 3 months mean catheterization and incontinent episodes were significantly decreased (p <0.05 and <0.001, respectively). On urodynamics we detected a significant increase in the UDC threshold and maximum cystometric capacity, and a significant decrease in UDC maximum pressure at the 1 and 3-month follow-ups compared to baseline (each p <0.001). At the same time points we detected a significant decrease in NGF bladder tissue content (each p <0.02).

CONCLUSIONS

BTX-A intravesical treatment induces a state of NGF deprivation in bladder tissue that persists at least up to 3 months. As caused by BTX-A, the decrease in acetylcholine release at the presynaptic level may induce a decrease in detrusor contractility and in NGF production by the detrusor muscle. Alternatively BTX-A can decrease the bladder level of neurotransmitters that normally modulate NGF production and release.

Recurrent inhibition of the bladder C fibre reflex in the cat and its response to naloxone

Recurrent inhibition of the bladder C fibre reflex was studied in adult female cats anaesthetized with alpha-chloralose. Test reflexes were evoked by electrical stimulation of bladder Adelta and C afferents in the right pelvic nerve and were recorded from the proximal end of a small ipsilateral pelvic nerve branch, transected close to the bladder. Such test reflexes were consistently depressed by repetitive electrical stimulation of the contralateral bladder pelvic nerve (20 Hz, 20 s) at intensities sufficient to recruit axons of bladder preganglionic neurones. The inhibition could be evoked after transection of the left dorsal roots S1-S4 and the sympathetic supply to the bladder but was abolished by transection of the pelvic nerve central to the site of stimulation. Hence, it most likely involved central recurrent collaterals of antidromically activated bladder preganglionic neurones. The reflex suppression was quite considerable - maximal C fibre reflexes were reduced to a group mean of 25% (+/- 9% confidence interval) of their control size. The effect had a slow onset, requiring a few seconds of conditioning stimulation to be revealed, and was very long lasting (minutes). Naloxone (0.01-0.5 mg kg(-1) i.v.) abolished the recurrent inhibition of both the C fibre and Adelta bladder reflexes, while inhibition from afferents in the dorsal clitoris nerve remained unchanged. It is concluded that the segmental bladder C fibre reflex and the spino-ponto-spinal Adelta micturition reflex are both targets of recurrent inhibition from bladder parasympathetic preganglionic neurones and that the effect involves an enkephalinergic mechanism.

Pharmacotherapy for Neurogenic Detrusor Overactivity

Chancellor MB, Anderson RU, Boone TB: Pharmacotherapy for neurogenic detrusor overactivity. Am J Phys Med Rehabil 2006;85:536-545. Patients with neurogenic detrusor overactivity are a heterogeneous group with voiding dysfunction secondary to neurologic injury or disease. The neurogenic detrusor overactivity syndrome, which may include urinary frequency, urgency, and incontinence, frequently contributes to a loss of independence, or even institutionalization. Urodynamic assessment provides the best method of quantifying and classifying neurogenic detrusor overactivity dysfunction in patients with primary diagnoses as diverse as Parkinson's disease, cerebral palsy, multiple sclerosis, spinal cord injury, and spina bifida. For many patients, management of urinary symptoms includes pharmacotherapy with an anticholinergic agent. Several novel approaches to managing neurogenic detrusor overactivity, including intravesical instillation of anticholinergic agents, vanilloids, and neurotoxins, are being investigated. For most patients, however, flexible dosing with an anticholinergic agent, with clean intermittent catheterization when indicated, has been shown to reduce the risks of urologic complications, improve levels of continence, and enhance patient quality of life in both children and adults.

TRPV1 antagonist, SB-366791, inhibits glutamatergic synaptic transmission in rat spinal dorsal horn following peripheral inflammation

The anti-hyperalgesic effects of TRPV1 receptor antagonists are well documented in animal models of pain, however, the precise site of their action is not known. Here we have examined the effects of the selective TRPV1 antagonist SB-366791 on glutamatergic synaptic transmission in substantia gelatinosa using spinal cord slices from either control rats or animals that had undergone a peripheral inflammation induced by intraplantar injection of Freund's complete adjuvant (FCA). In control animals, SB-366791 (30 microM) had no effect on spontaneous excitatory post-synaptic currents (sEPSC) or evoked EPSCs. In slices from FCA-inflamed animals, SB-366791 decreased sEPSC frequency to 66+/-8% of control in 5/10 neurones, and decreased miniature glutamatergic EPSCs (mEPSC) frequency to 63+/-4% of control, in 6/7 neurones; with no significant effect on sEPSC or mEPSC amplitude. Dorsal root evoked EPSCs at C-fibre intensity were reduced to 72+/-6% of control by SB-366791 (30 microM) in 3/4 neurones from FCA-treated animals. In conclusion, SB-366791 inhibited glutamatergic transmission in a subset of neurones via a pre-synaptic mechanism following peripheral inflammation. We hypothesise that during peripheral inflammation spinal TRPV1 becomes tonically active, promoting the synaptic release of glutamate. These results provide evidence for a mechanism by which TRPV1 contributes to inflammatory pain and provides a basis for the understanding of the efficacy of TRPV1 antagonists.

Chemical genetics reveals an RGS/G-protein role in the action of a compound

We report here on a chemical genetic screen designed to address the mechanism of action of a small molecule. Small molecules that were active in models of urinary incontinence were tested on the nematode Caenorhabditis elegans, and the resulting phenotypes were used as readouts in a genetic screen to identify possible molecular targets. The mutations giving resistance to compound were found to affect members of the RGS protein/G-protein complex. Studies in mammalian systems confirmed that the small molecules inhibit muscarinic G-protein coupled receptor (GPCR) signaling involving G-αq (G-protein alpha subunit). Our studies suggest that the small molecules act at the level of the RGS/G-αq signaling complex, and define new mutations in both RGS and G-αq, including a unique hypo-adapation allele of G-αq. These findings suggest that therapeutics targeted to downstream components of GPCR signaling may be effective for treatment of diseases involving inappropriate receptor activation.

The authors have utilized Caenorhabditis elegans, and yeast genetics, combined with mammalian tissue and cell culture experiments to investigate the mechanism of action of a unique set of small molecules. These molecules are active in tissue models of urinary incontinence and allow for increased bladder filling. In the course of studying sensitivity and resistance to these compounds, Fitzgerald et al. uncovered novel alleles of RGS and Gq proteins. Further characterization of one such allele identified that its action conferred a hypo-adaptive phenotype on yeast during pheromone signaling assays. Their data as a whole indicate that these small molecules are able to diminish signaling from G-protein coupled receptors (GPCR) downstream of the receptors themselves. Since GPCR signaling is very important in many diseases in humans, the novel mechanism of these compounds may offer new ways to treat human disease.

Peptidergic sensory and parasympathetic fiber sprouting in the mucosa of the rat urinary bladder in a chronic model of cyclophosphamide-induced cystitis

In this study, we used a well-established animal model to investigate changes in the peptidergic and parasympathetic innervation of the bladder following chronic bladder inflammation. Adult female Sprague-Dawley rats were injected with either 70 mg/kg cyclophosphamide diluted in saline, i.p., once every 3 days or saline. After 10 days, all animals were tested for urinary frequency and number of low volume voids, as well as symptoms of spontaneous pain. At the end of 12 days, all animals were perfused with histological fixatives and the urinary bladders processed for immunofluorescence using antibodies against calcitonin gene-related peptide and the vesicular acetylcholine transporter as markers, respectively, of peptidergic primary afferent fibers and parasympathetic efferent fibers. We show that animals treated with cyclophosphamide had inflamed bladders and displayed high urinary frequency as well as some indicators of spontaneous pain, such as piloerection and a rounded-back posture. Furthermore, they had a significant increase in the density of both parasympathetic and peptidergic sensory fibers in the bladder mucosa and an increase in peptidergic sensory fibers in the detrusor muscle. Based on these results, we suggest that peripheral sprouting of parasympathetic and peptidergic fibers could be a mechanism responsible for sensitization of the bladder, leading to urinary symptoms. Since we observed that the parasympathetic and peptidergic fibers often wrapped around one another and that their varicosities were very close, these two fiber populations may be interacting with each other to lead to and maintain sensitization. Future studies are required to establish the role of this fiber sprouting in bladder symptoms.

Peptidergic sensory and parasympathetic fiber sprouting in the mucosa of the rat urinary bladder in a chronic model of cyclophosphamide-induced cystitis

In this study, we used a well-established animal model to investigate changes in the peptidergic and parasympathetic innervation of the bladder following chronic bladder inflammation. Adult female Sprague-Dawley rats were injected with either 70 mg/kg cyclophosphamide diluted in saline, i.p., once every 3 days or saline. After 10 days, all animals were tested for urinary frequency and number of low volume voids, as well as symptoms of spontaneous pain. At the end of 12 days, all animals were perfused with histological fixatives and the urinary bladders processed for immunofluorescence using antibodies against calcitonin gene-related peptide and the vesicular acetylcholine transporter as markers, respectively, of peptidergic primary afferent fibers and parasympathetic efferent fibers. We show that animals treated with cyclophosphamide had inflamed bladders and displayed high urinary frequency as well as some indicators of spontaneous pain, such as piloerection and a rounded-back posture. Furthermore, they had a significant increase in the density of both parasympathetic and peptidergic sensory fibers in the bladder mucosa and an increase in peptidergic sensory fibers in the detrusor muscle. Based on these results, we suggest that peripheral sprouting of parasympathetic and peptidergic fibers could be a mechanism responsible for sensitization of the bladder, leading to urinary symptoms. Since we observed that the parasympathetic and peptidergic fibers often wrapped around one another and that their varicosities were very close, these two fiber populations may be interacting with each other to lead to and maintain sensitization. Future studies are required to establish the role of this fiber sprouting in bladder symptoms.

Newer pharmacologic options in management of overactive bladder syndrome

PURPOSE OF REVIEW

Urinary incontinence is an under-reported epidemic that currently affects an estimated 13 million people in the United States, of whom about 11 million are women, according to the National Institute of Diabetes and Digestive and Kidney Diseases (Publication No. 02-4132). Because many patients are unaware of curative options and perceive it to be an inevitable outcome of advancing age, they fail to report their symptoms and increase their risk of developing associated co-morbid disease. Failure to diagnose and treat this condition increases financial burdens on individuals, their families and health care organizations.

RECENT FINDINGS

Pharmacologic therapy of urge incontinence previously had limited treatment success because efficacious drugs were poorly tolerated, resulting in low patient compliance. Tolerance and effectiveness continue to be improved due to innovative new drugs and alternative delivery systems.

SUMMARY

The goal of this review is to update the clinician on the efficacy and the tolerability of established and investigational pharmacologic modalities of therapy.

The role of the vanilloid (capsaicin) receptor (TRPV1) in physiology and pathology

The cloning of the vanilloid receptor 1 opened a floodgate for discoveries regarding the function of this complex molecule. It has been found that, in addition to heat, protons and vanilloids, this receptor also responds to various endogenous ligands. Furthermore, it has been also emerged that, through associations with other molecules, the vanilloid receptor 1 plays an important role in the integration of various stimuli and modulation of cellular excitability. Although, originally, the vanilloid receptor 1 was associated with nociceptive primary afferent fibres, it has been gradually revealed that it is broadly expressed in the brain, epidermis and visceral cells. The expression pattern of the vanilloid receptor 1 indicates that it could be involved in various physiological functions and in the pathomechanisms of diverse diseases. Here, we summarise the molecular, pharmacological and physiological characteristics, and putative functions, of the vanilloid receptor 1, and discuss the therapeutic potential of this molecule.