Antimuscarinic Drug Inhibits Detrusor Overactivity Induced by Topical Application of Prostaglandin E 2 to the Urethra With a Decrease in Urethral Pressure

Performance of urinary biomarkers in differentiating dysfunctional voiding in women with overactive bladder syndrome: a prospective pilot study

PURPOSE

Dysfunctional voiding (DV) in women is a common disorder that causes bladder outlet obstruction (BOO) and may aggravate overactive bladder (OAB) symptoms. The diagnosis of DV relies on clinical alertness and videourodynamic study (VUDS). In this pilot study, we aimed to explore the diagnostic potential of urinary biomarkers in women with DV.

METHODS

Women who visited our institute for the management of OAB were enrolled in this prospective study. Urine samples were collected before treatment and urinary proteins were quantified using enzyme-linked immunosorbent assay (ELISA) kits. Patients with DV and patients with normal tracings were included in the study and control group, respectively. The patients with DV were further divided into two subgroups: those with and those without detrusor overactivity (DO). VUDS parameters and urinary protein levels were compared between each subgroup.

RESULTS

A total of 67 women were enrolled. There were 47 patients with VUDS-diagnosed DV and 20 patients in the control group. Urinary 8-OHdG level (32.65 vs. 15.59, p < 0.001) and urinary TNF-α level (1.43 vs. 0.83, p = 0.031) were significantly higher in the DV group, and urinary IL-2 level (0.29 vs. 0.83, p < 0.001) was significantly lower in the DV group. Among the DV patients, urinary PGE2 level was higher in the DO group (240.4 vs 149.6, p = 0.049).

CONCLUSIONS

In women with DV, urinary 8-OHdG level is elevated compared to women with normal VUDS. Urinary PGE2 level is elevated in patients with DV and DO. These finding suggests increased reactive-oxidative stress response and detrusor hyperactivity in DV patients. Urinary biomarkers can serve as potential non-invasive diagnostic tools in women with OAB.

The influence of Potentilla chinensis aqueous extract on urinary bladder function in retinyl acetate-induced detrusor overactivity in rats

INTRODUCTION & OBJECTIVES

In overactive bladder (OAB) therapy several herbal medicines presented promising effects, however the results are sparse to provide their efficacy. Herbals may become a popular alternative for OAB therapy. Therefore, we investigated whether Potentilla chinensis extract (PCE) would reverse retinyl acetate (RA)-induced detrusor overactivity (DO).

MATERIAL & METHODS

60 rats were divided into 4 groups, as follows: I - control, II - rats with RA-induced DO, III - rats received PCE in dose of 500 mg/kg, and IV - rats with RA-induced DO which received PCE. PCE or vehicle were administered orally for 14 days. The cystometry and bladder blood flow assessment were performed 3 days after the last dose of the PCE. Then the rats were put into the metabolic cages for 24 h. Next, urothelium thickness measurement and biochemical analyses were performed. < /p><p> Results. Intravesical infusion of RA solution induced DO. PCE had no influence on the urinary bladder function and&nbsp; micturition cycles in normal rats. PCE diminished the severity of RA-induced DO. In the urothelium the RA induced the elevation of ATP, CGRP, substance P, VEGF-A, OTC3, and ERK1/2. The concentration of NOS2, CDH1, and ZO1 decreased. Moreover, RA affected the concentration of SNARE proteins (increased concentration of SNAP23, SNAP25, and SV2A). Also in detrusor the elevated level of ROCK1 and VAChT were observed. In turn, PCE in RA-induced DO caused a reversal of the described biochemical changes within urothelium, detrusor muscle and urine. < /p><p> Conclusions. PCE attenuates detrusor overactivity. The potential mechanisms of action of PCE in the urinary bladder seem to be multifactorial and complex. PCE seems to become a reasonable novel OAB therapy.

Castration increases PGE2 release from the bladder epithelium in male rats

AIMS

Androgen deprivation therapy has been widely used for the treatment of prostate cancer. While sexual side effects including decreased sexual desire and function are well studied, there are only limited reports about its influences on lower urinary tract symptoms. The aim of this study is to clarify the influences of castration in male rats.

METHODS

Ten-week-old male rats were divided into treatment group (bilateral orchiectomy) and control group (sham surgery). Two-months after the surgery, adenosine triphosphate (ATP), prostaglandin E2 (PGE2), and nerve growth factor (NGF) released from stretched bladder epithelium were measured by luciferin-luciferase assay or ELISA. The mRNA levels of bladder cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) were determined by real-time PCR. The protein level of bladder COX-2 was analyzed by western blot analysis. Bio-Plex Pro cytokine assay was performed to quantify the level of proinflammatory cytokine interleukin (IL)-1β in the bladder.

RESULTS

The PGE₂ release from stretched bladder epithelium was significantly increased after castration, which increased more than 50% compared with control. On the other hand, those of ATP and NGF were not different from those of the controls. Testosterone replacement restored the PGE₂ increase. Castration significantly increased bladder IL-1β protein level and COX-2 at both mRNA and protein levels, whereas caused no marked changes in the COX-1 mRNA level.

CONCLUSIONS

These findings suggest that castration induces inflammation in the rat bladder, which causes elevated PGE₂ release from bladder epithelium and may finally contribute to the disruption of bladder storage function.

OAB without an overactive bladder in the acute prostaglandin E2 rat model

Intravesical prostaglandin E2 (PGE2) was previously used to induce overactive bladder (OAB) symptoms, as it reduces bladder capacity in rats and causes a "strong urgency sensation" in healthy women. However, the mechanism by which this occurs is unclear. To clarify how PGE2 reduces bladder capacity, 100 µM PGE2 was administered intravesically during open, single-fill cystometry with simultaneous measurement of sphincter EMG in the urethane-anesthetized female Wistar rat. PGE2 was also applied to the urethra or bladder selectively by use of a ligature at the bladder neck before (urethra) or during (bladder) closed-outlet, single-fill cystometry. Additional tests of urethral perfusion with PGE2 were made. PGE2 decreased bladder capacity, increased voiding efficiency, and increased sphincter EMG during open cystometry compared with saline controls. The number of nonvoiding contractions did not change with PGE2; however, bladder compliance decreased. During closed-outlet cystometry, PGE2 applied only to the bladder or the urethra did not decrease bladder capacity. Urethral infusion of PGE2 decreased urethral perfusion pressure. Taken together, these results suggest that intravesical PGE2 may decrease bladder capacity by targeting afferents in the proximal urethra. This may occur through urethral relaxation and decreased bladder compliance, both of which may increase activation of proximal urethra afferents from distension of the proximal urethra. This hypothesis stands in contrast to many hypotheses of urgency that focus on bladder dysfunction as the primary cause of OAB symptoms. Targeting the urethra, particularly urethral smooth muscle, may be a promising avenue for the design of drugs and devices to treat OAB.

Efficacy and safety of botulinum toxin injection for interstitial cystitis/bladder pain syndrome: a systematic review and meta-analysis

PURPOSE

To investigate the overall treatment efficacy and safety of botulinum toxin type A (BoNTA) injections compared with placebo in interstitial cystitis/bladder pain syndrome (IC/BPS).

METHODS

We conducted a systematic review and meta-analysis of the published literature in PubMed, Cochrane Library, and EMBASE on BoNTA use in IC/BPS. Outcome measures included changes of OLS, ICSI, ICPI, VAS, frequency, nocturia, FBC, Qmax, and PVR from baseline and also included adverse events.

RESULTS

A total of five studies were included, with a total sample size of 252 subjects (133 subjects in the experimental group and 119 subjects in the control group). The duration of follow-up ranged from 8 to 12 weeks. The BoNTA dosage was from 50 to 200 U. The pooled overall SMD in the mean change of VAS for the BoNTA group versus the placebo group was -0.49 (95 % CI -0.74, -0.23). There were also significant improvements in ICPI and frequency. The other outcomes (ICSI, nocturia, Qmax, and FBC) were not statistically different between the two groups.

CONCLUSION

Although BoNTA is not regulatory approved indication, this first evidence-based systematic review and meta-analysis of BoNTA injection for IC/BPS showed significant differences in efficacy of treatment compared with placebo, especially for pain control, and also showed no differences in the rate of procedure-related adverse events.

Medication effects on periurethral sensation and urethral sphincter activity

AIM

The aim of this study was to characterize urethral neuromuscular function before and 2 weeks after medication therapy.

METHODS

Premenopausal women without lower urinary tract symptoms were randomly allocated to 1 of the 6 medications for 2 weeks (pseudoephedrine ER of 120 mg, imipramine of 25 mg, cyclobenzaprine of 10 mg, tamsulosin of 0.4 mg, solifenacin of 5 mg, or placebo). At baseline and after medication, participants underwent testing: quantitative concentric needle electromyography (CNE) of the urethral sphincter using automated multimotor unit action potential software, current perception threshold (CPT) testing to measure periurethral sensation, and standard urodynamic pressure flow studies (PFS). Nonparametric tests were used to compare pre-post differences.

RESULTS

Fifty-six women had baseline testing, 48 (85.7%) completed follow-up CNE, and 49 (87.5%) completed follow-up CPT and PFS testing. Demographics showed no significant differences among medication groups with respect to age (mean, 34.3; SD, 10.1), body mass index (mean, 31.8; SD, 7.5), parity (median, 1; range, 0-7), or race (14% Caucasian, 80% African American). The PFS parameters were not significantly different within medication groups. No significant pre-post changes in CNE values were noted; however, trends in amplitudes were in a direction consistent with the expected physiologic effect of the medications. With CPT testing, a trend toward increased urethral sensation at the 5-Hz stimulation level was observed after treatment with pseudoephedrine (0.15-0.09 mA at 5 Hz, P = 0.03).

CONCLUSIONS

In women without lower urinary tract symptoms, pseudoephedrine improved urethral sensation but not urethral neuromuscular function on CNE or PFS. Imipramine, cyclobenzaprine, tamsulosin, solifenacin, and placebo did not change urethral sensation or neuromuscular function.

Potential Biomarkers Utilized to Define and Manage Overactive Bladder Syndrome

Clinical diagnosis of overactive bladder (OAB) syndrome has great variation and usually can only be based on subjective symptoms. Measurement of urgency severity score in adjunct with voiding diary may reflect the occurrence of OAB and incontinence severity in daily life. Urodynamic study can detect detrusor overactivity (DO), but not in all OAB patients. A more objective way and less invasive tool to diagnose and assess therapeutic outcome in OAB patients is needed. Recent investigations of the potential biomarkers for OAB include urinary and serum biomarkers and bladder wall thickness. Evidence has also shown that urinary proteins, such as nerve growth factor (NGF) and prostaglandin E2 (PGE2 ) levels increase in patients with OAB, bladder outlet obstruction (BOO) and DO. Patients with OAB have significantly higher urinary NGFlevels and urinary NGF levels decrease after antimuscarinic therapy and further decrease after detrusor botulinum toxin injections. However, the sensitivity of single urinary protein in the diagnosis of OAB is not high and several lower urinary tract diseases may also have elevated urinary NGF levels. Searching for a group of inflammatory biomarkers by microsphere-based array in urine might be a better method in differential diagnosis of OAB from interstitial cystitis, urinary tract infection (UTI) or urolithiasis. Bladder wall thickness has been widely investigated in the diagnosis of BOO and pediatric voiding dysfunction.The role of bladder wall thickness in the diagnosis of OAB, however, has not reach a consistent conclusion. We hereby review the latest medical advances in this field.

Chronic psychological stress in high-anxiety rats induces sustained bladder hyperalgesia

OBJECTIVE

To evaluate whether anxiety-prone rats exposed to chronic water avoidance stress (WAS) develop visceral bladder hyperalgesia in addition to increased voiding frequency and anxiety-related behaviors.

MATERIALS AND METHODS

Female Wistar-Kyoto (WKY) rats were exposed to chronic (10-day) WAS or sham paradigms. Referred hyperalgesia and tactile allodynia were tested using von Frey filaments applied to the suprapubic region and plantar region of the hindpaw, respectively. To confirm that suprapubic nociception represented referred visceral bladder hyperalgesia, we recorded abdominal visceromotor responses (VMR) to slow (100 μl/min) and fast (1 cc/sec) bladder filling with room temperature or ice-cold saline. We assessed the development of hyperalgesia over the 10-day WAS protocol and the durability of increased pain sensations over time.

RESULTS

Animals exposed to chronic WAS had significantly lower hindpaw withdrawal thresholds post-stress and significant differences in referred hyperalgesia. Rats exposed to chronic WAS demonstrated an increased pain response to suprapubic stimulation and decreased response threshold to mechanical hindpaw stimulation by day 8 of the stress protocol, which persisted for more than one month. Animals exposed to chronic WAS showed increased VMR to fast filling and ice water testing in comparison to sham animals. Cystometry under anesthesia did not show increases in the frequency of non-voiding contractions.

CONCLUSION

Chronic WAS induces sustained bladder hyperalgesia, lasting over a month after exposure to stress. The urinary frequency demonstrated previously in anxiety-prone rats exposed to chronic WAS seems to be associated with bladder hyperalgesia, suggesting that this is a potential model for future studies of bladder hypersensitivity syndromes such as interstitial cystitis/painful bladder syndrome (IC/PBS).

Changes in prostaglandin E2 in patients with idiopathic overactive bladder syndrome after botulinum toxin type A treatment: is there a clinical benefit?

BACKGROUND

The causality of overactive bladder syndrome (OAB) is still not fully understood. Several studies indicate a significant increase of prostaglandin E2 (PGE2) in patients with OAB. However, in order to clarify whether these compounds can help to objectify the clinical diagnosis, further studies are needed. This prospective study aims to analyze PGE2 blood levels (sPGE2) in patients with OAB before and after botulinum toxin type A (BoNT-A) therapy.

METHODS

Blood samples were obtained from 56 patients (52y, 18-87) with idiopathic OAB. sPGE2 levels were measured before and 4 weeks after BoNT-A treatment by enzyme linked immunosorbent assay (ELISA). 31 healthy persons with normal bladder function served as control group (59 y, 21-72). sPGE2 was set in relation to clinical data and the severity of OAB (wet/dry). The statistical data analysis was performed by using the non-parametric Mann-Whitney U test and paired t-test.

RESULTS

Significant higher sPGE2 levels were detected in patients with OAB compared to members of the control group (2750 pg/ml vs. 1674 pg/ml, p < 0.005). Furthermore sPGE2 levels were increased in patients with OAB wet compared to OAB dry (p <0.01). In 30 patients sPGE2 levels decreased significantly after BoNT-A treatment compared to baseline (2995 pg/ml vs. 1486 pg/ml, p <0.005). Patients reported an average drug effect of 9 month (0-19); incontinence pads were needed significantly less frequent (p < 0.05). 3 patients reported no postoperative effect. sPGE2 increased in two patients compared to initial levels, a single patient showed a remotely decreased sPGE2. Six patients were treated repeatedly with BoNT-A after showing an sPGE2 re-rise.

CONCLUSIONS

sPGE2-level is increased in patients with OAB. We could prove a significant decrease of sPGE2 after BoNT-A treatment. In this small cohort we could demonstrate a correlation between OAB and sPGE2, especially in the non-responder group. The use of sPGE2 as a biomarker in diagnostics and follow-up after therapy seems promising. To what extent sPGE2 can be useful as such needs to be examined prospectively in a larger population.

Pathophysiology of the urothelium and detrusor

Conventional wisdom now agrees that symptoms of overactive bladder (OAB) seem to emanate from an aberration in the voiding reflex, leading to involuntary detrusor contractions of either neurogenic or myogenic origin. Furthermore, emerging evidence also encourages us to adopt a new paradigm, in which bladder urothelium is not just a simple barrier but an active contributor to bladder function. In this paradigm, aberration in sensory mechanisms emanating from the urothelium can also contribute to OAB symptoms through altered excitability of afferents in the bladder leading to increased bladder sensation. The high density of muscarinic receptors expressed on urothelium can not only mediate release of urothelium-derived inhibitory factor, but can also be seen as an alternative site of action for antimuscarinic drugs. Urothelium also expresses a host of other receptors such as TRPV1 and TRPM8, whose functional role is yet to be confirmed.

Biomarkers in overactive bladder: a new objective and noninvasive tool?

Overactive bladder syndrome (OAB) is a highly prevalent urinary dysfunction, with considerable economic and human costs. Clinical diagnosis of OAB is still based on subjective symptoms. A new accurate, objective and noninvasive test to diagnose OAB and assess therapeutic outcome is lacking. Recent studies in lower urinary tract (LUT) dysfunctions, particularly in OAB patients, indicate that urinary proteins (neurotrophins, prostaglandins, and cytokines), serum C reactive protein, and detrusor wall thickness are altered, and such changes could be used as biomarkers of the disease. Nowadays, increasing emphasis has been given to the role of urinary neurotrophins, namely nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF), as key players in some urinary dysfunctions. Although recently considered to be a bladder dysfunction biomarker, urinary NGF presents low sensitivity and specificity. Preliminary results suggest that BDNF may serve as a more efficient biomarker. Even though we have to wait for future studies to confirm the potential role of NGF and BDNF as OAB biomarkers, it is already clear that neurotrophins will contribute to elucidate the physiopathological basis of OAB. Herein are reviewed the latest advances in this new and exciting field, the detection and clinical application of emerging OAB biomarkers.

Comparative analysis of the effects of antimuscarinic agents on bladder functions in both nonhuman primates and rodents

Both the physiological role of muscarinic receptors for bladder function and the therapeutic efficacy of antimuscarinic agents for overactive bladder syndrome are well documented. We investigated the effect of antimuscarinic agents with different subtype selectivity on urodynamic parameters in nonhuman primates and rodents and compared plasma levels of these agents between species. Anesthetized rhesus monkeys were transurethrally catheterized, and the bladder was infused with saline. Urodynamic parameters were measured before and after intravenous drug administration. Tolterodine (nonselective) and oxybutynin (moderately M(3)-selective) increased bladder capacity at lower doses than those required to decrease micturition pressure. However, higher doses of darifenacin (M(3)-selective) were needed to increase the bladder capacity than those needed to decrease the micturition pressure. In rats, tolterodine had no effect on the bladder capacity but decreased the micturition pressure at all of the doses administered. Oxybutynin also decreased micturition pressure and increased bladder capacity at the highest dose. Plasma levels of these drugs overlap in both species. These results suggest that, in addition to the M(3) receptor, other muscarinic receptor subtypes contribute to regulate bladder storage function in nonhuman primates, since less subtype-selective tolterodine and oxybutynin showed higher specificity to the bladder capacity effect than the effect on micturition pressure compared with M(3)-selective darifenacin. In addition, the role of muscarinic receptors in bladder storage function varies between primates and rodents. Compared with rodents, muscarinic receptors may play a more active role during the storage phase to regulate the functional bladder capacity in primates.

Novel biomarkers for overactive bladder

Biomarkers constitute any objectively measurable indicator of a biological process. The classic biomarker used in the diagnosis of overactive bladder (OAB) has been detrusor overactivity, which is assessed urodynamically. In the search for a reliable, noninvasive alternative to urodynamics, interest has focused on genetic, imaging, and urinary factors. Along with other cytokines detectable in urine, prostaglandin E2 and nerve growth factor are indicators of low-grade inflammation. Although they correlate with OAB symptom severity, they have not been shown to have independent prognostic benefit. Imaging biomarkers have been investigated since the earliest days of video urodynamics. Despite extensive research on the ultrasonographic estimation of bladder wall thickness, further standardization of the technique is required before conclusions can be reached regarding diagnostic accuracy. Genetic factors contribute approximately half of the total risk for urgency incontinence. Functional polymorphisms of the cytochrome P450 IID6 gene significantly alter the metabolism of some commonly used anticholinergic drugs, but no genetic loci that influence risk of OAB have been definitively identified. The first genome-wide association studies for OAB are in progress, and should identify new susceptibility genes. Although current putative biomarkers correlate with OAB severity, much future work is required to assess their prognostic value, and establish their role in clinical practice.

[Clinical efficacy of tolterodine for patients with overactive bladder after insufficient efficacy by monotherapy with alpha1-adrenoceptor antagonist]

PURPOSE

The efficacy of alpha1-adrenoceptor (alpha1-AR) antagonist and anticholinergic agent combined therapy for patients with benign prostatic hyperplasia (BPH) together with overactive bladder (OAB) has been controversial. The purpose of this study was to evaluate the effect of tolterodine combined with alpha1-AR antagonist for patients with BPH and OAB after insufficient efficacy by monotherapy with alpha1-AR antagonist. The adverse event of this combined therapy was also assessed.

MATERIALS AND METHODS

The study included 47 patients with BPH, whose OAB symptom persisted (OAB symptom score; OABSS > or =3) after monotherapy with alpha1-AR antagonist for more than 4 weeks. The mean age was 72.9 years and the mean prostate volume was 29.8 ml. Four mg/day of tolterodine with alpha-AR antagonist was administered for 8 weeks to patients. International prostate symptom score (IPSS), quality of life (QOL) index, OABSS, King's Health Questionnaire (KHQ) and residual urine volume (RUV) were assessed before and after combined therapy.

RESULTS

Six patients were dropped out from this study because of dry mouth, constipation, onset of other disease and insufficient efficacy by self-judgment. IPSS (from 15.1 +/- 6.8 to 11.0 +/- 7.9; P < 0.01), QOL index (from 4.3 +/- 1.1 to 3.6 +/- 1.3; P < 0.01) and OABSS (from 7.0 +/- 3.0 to 5.4 +/- 2.9; P < 0.01) of 41 patients improved significantly by combined therapy. The storage symptom of IPSS subscore improved significantly (from 8.0 +/- 2.9 to 6.5 +/- 2.8; P < 0.01), whereas the voiding symptom did not improve. Regarding KHQ, the score of 3 domains (impact on life, role limitation, and physical limitation) improved significantly (P < 0.05). RUV did not change and no serious adverse event including urinary retention was found in this study.

CONCLUSIONS

This study reveals that the combined therapy of alpha-AR antagonist and tolterodine represents an effective and safe treatment modality for patients with BPH and OAB, whose OAB symptom was not improved by antecedent monotherapy with alpha-AR antagonist.