Early in life stressful events induce chronic visceral pain and changes in bladder function in adult female mice through a mechanism involving TRPV1 and alpha 1A adrenoceptors.

BACKGROUND: Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic pain disorder with multiple phenotypes, one of which is associated with an overactive adrenergic system. OBJECTIVE: We investigated if the maternal deprivation model (MDM) in female and male mice mimics IC/BPS phenotype and if the overstimulation of alpha 1A adrenoceptor (A1AAR) and the crosstalk with transient receptor potential vanilloid-1 (TRPV1) are involved in the generation of pain and bladder functional changes. DESIGN, SETTING, AND PARTICIPANTS: C57BL/6 female and male mice were submitted to MDM. TRPV1 knockout (KO) mice were used to study TRPV1 involvement. Silodosin administration to MDM mice was used to study A1AAR involvement. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was chronic visceral pain measured by Von Frey filaments analysis (effect size: 3 for wild type, 3.9 for TRPV1 KO). Bladder changes were secondary outcome measurements. Unpaired T test, Mann-Whitney test, one-way analysis of variance followed by Newman-Keuls multiple comparisons test, and Kruskal-Wallis followed by Dunn's multiple comparisons test were used where appropriate. RESULTS AND LIMITATIONS: MDM induces pain behavior in female and not in male mice. Bladder afferents seem sensitize as MDM also increase the number of small volume spots voided, the bladder reflex activity, and urothelial damage. These changes were similarly absent after A1AAR blockade with silodosin or by TRPV1 gene KO. The main limitation is the number/type of pain tests used. CONCLUSIONS: MDM induced in female mice is able to mimic IC/BPS phenotype, through mechanisms involving A1AAR and TRPV1. Therefore, the modulation of both receptors may represent a therapeutic approach to treat IC/BPS patients.

Beyond the urothelium: Interplay between autonomic nervous system and bladder inflammation in urinary tract infection, bladder pain syndrome with interstitial cystitis and neurogenic lower urinary tract dysfunction in spinal cord injury-ICI-RS 2023.

INTRODUCTION: Inflammation and neuronal hypersensitivity are reactive protective mechanisms after urothelial injury. In lower urinary tract dysfunctions (LUTD), such as urinary tract infection (UTI), bladder pain syndrome with interstitial cystitis (BPS/IC) and neurogenic LUTD after spinal cord injury (SCI), chronic inflammation can develop. It is unclear how the protective reactionary inflammation escalates into chronic disease in some patients. METHODS: During its 2023 meeting in Bristol, the International Consultation on Incontinence-Research Society (ICI-RS) reviewed the urothelial and inflammatory changes after UTI, BPS/IC and SCI. Potential factors contributing to the evolution into chronic disease were explored in a think-tank. RESULTS: Five topics were discussed. (1) Visceral fat metabolism participates in the systemic pro-inflammatory effect of noradrenalin in BPS/IC and SCI. Sympathetic nervous system-adipocyte-bladder crosstalk needs further investigation. (2) Sympathetic hyperactivity also potentiates immune depression in SCI and needs to be investigated in BPS/IC. Gabapentin and tumor necrosis factor-α are promising research targets. (3) The exact peripheral neurons involved in the integrative protective unit formed by nervous and immune systems need to be further identified. (4) Neurotransmitter changes in SCI and BPS/IC: Neurotransmitter crosstalk needs to be considered in identifying new therapeutic targets. (5) The change from eubiosis to dysbiosis in SCI can contribute to UTI susceptibility and needs to be unraveled. CONCLUSIONS: The think-tank discussed whether visceral fat metabolism, immune depression through sympathetic hyperactivity, peripheral nerves and neurotransmitter crosstalk, and the change in microbiome could provide explanations in the heterogenic development of chronic inflammation in LUTD. High-priority research questions were identified.

Intratrigonal OnabotulinumtoxinA Improves Bladder Symptoms and Quality of Life in Patients with Bladder Pain Syndrome/Interstitial Cystitis: A Pilot, Single Center, Randomized, Double-Blind, Placebo Controlled Trial.

PURPOSE: We compared the efficacy and safety of trigonal injections of onabotulinumtoxinA and saline in patients with bladder pain syndrome/interstitial cystitis. MATERIALS AND METHODS: This phase II study enrolled women who had had bladder pain syndrome/interstitial cystitis for more than 6 months and pain for 4 months or longer on a visual analogue scale of 0 to 10, which were refractory to common treatment. OnabotulinumtoxinA 100 U in 10 or saline as placebo in 9 was administered as 10 trigonal injections of 1 ml. The primary study end point was the change from baseline pain intensity reported at week 12. Additional end points included O'Leary-Sant scores, micturition frequency, quality of life at week 4, 8 and 12, and the treatment benefit scale at week 12. Safety assessments included urinary tract infection, post-void residual urine and the initiation of clean intermittent catheterization. RESULTS: At week 12 onabotulinumtoxinA had significantly reduced pain compared with saline (mean ± SD -3.8 ± 2.5 vs -1.6 ± 2.1, p <0.05). The proportion of patients who achieved a 50% or greater reduction in the pain visual analog scale was 60% for onabotulinumtoxinA vs 22% for placebo. OnabotulinumtoxinA significantly improved O'Leary-Sant scores and quality of life over placebo at weeks 4, 8 and 12. Important numerical reductions in voiding frequency were also observed with the toxin. OnabotulinumtoxinA was well tolerated. Urinary tract infections developed in 3 patients who received onabotulinumtoxinA vs 2 who received saline. Mean post-void residual urine at week 12 was 5 ± 13 ml for onabotulinumtoxinA vs 0 ml with saline. This study had the limitations inherent to a single center trial with a small number of patients enrolled. CONCLUSIONS: OnabotulinumtoxinA 100 U caused significant and clinically relevant improvements in bladder pain and quality of life in patients with bladder pain syndrome/interstitial cystitis refractory to common therapy. It was also well tolerated.

Expression of cleaved SNAP-25 after bladder wall injection of onabotulinumtoxina or abobotulinumtoxina: A comparative study in the mice.

AIMS: To study the expression of cleaved synaptosomal associated protein of 25 kDa (cSNAP-25) in the bladder wall injected with onabotulinumtoxinA (onabotA) or abobotulinumtoxinA (abobotA) and compare the relative potency of these two brands. METHODS: One injection of 0.5 U of onabotA or abobotA diluted in 2 µl of saline was carried out in the bladder dome of adult female mice, whose bladders were exposed by laparotomy. Three days later bladders were collected, divided in five segments (dome, upper, middle and lower body, and trigone) and each one was sectioned and immunoreacted against cSNAP-25, the end product of botulinum toxin type A (BoNT/A) activity. From each of the five segments one section was taken at random and the number of cSNAP-25 immunoreactive (IR) fibers was determined. RESULTS: Each injection resulted in the cleavage of SNAP-25 in all bladder sections, including those of the more distant segment from the injection point. The average number of cSNAP-25 positive fibers was higher in the onabotA, 341 ± 301, than in the abobotA-treated mice, 208 ± 152 (P = 0.003). The number of cSNAP-25 IR fibers varied three to five-fold between animals of each experimental group. CONCLUSIONS: These findings confirm that, when injected in the bladder wall, in the same unit amount and same volume, onabotA is 1.6 times more potent to cleave SNAP-25 than abobotA. The conversion ratio suggested by these experiments is 1:1.6 between onabotA and abobotA. Each injection, although preformed in the same way, may induce substantially different amounts of cSNAP-25. Neurourol. Urodynam. 36:86-90, 2017. © 2015 Wiley Periodicals, Inc.

Co-administration of transient receptor potential vanilloid 4 (TRPV4) and TRPV1 antagonists potentiate the effect of each drug in a rat model of cystitis.

OBJECTIVE: To investigate transient receptor potential vanilloid 4 (TRPV4) expression in bladder afferents and study the effect of TRPV4 and TRPV1 antagonists, alone and in combination, in bladder hyperactivity and pain induced by cystitis. MATERIAL AND METHODS: TRPV4 expression in bladder afferents was analysed by immunohistochemistry in L6 dorsal root ganglia (DRG), labelled by fluorogold injected in the urinary bladder. TRPV4 and TRPV1 co-expression was also investigated in L6 DRG neurones of control rats and in rats with lipopolysaccharide (LPS)-induced cystitis. The effect of TRPV4 antagonist RN1734 and TRPV1 antagonist SB366791 on bladder hyperactivity and pain induced by cystitis was assessed by cystometry and visceral pain behaviour tests, respectively. RESULTS: TRPV4 is expressed in sensory neurones that innervate the urinary bladder. TRPV4-positive bladder afferents represent a different population than the TRPV1-expressing bladder afferents, as their co-localisation was minimal in control and inflamed rats. While low doses of RN1734 and SB366791 (176.7 ng/kg and 143.9 ng/kg, respectively) had no effect on bladder activity, the co-administration of the two totally reversed bladder hyperactivity induced by LPS. In these same doses, the antagonists partially reversed bladder pain behaviour induced by cystitis. CONCLUSIONS: TRPV4 and TRPV1 are present in different bladder afferent populations. The synergistic activity of antagonists for these receptors in very low doses may offer the opportunity to treat lower urinary tract symptoms while minimising the potential side-effects of each drug.

Can the adrenergic system be implicated in the pathophysiology of bladder pain syndrome/interstitial cystitis? A clinical and experimental study.

AIMS: To evaluate sympathetic system activity in bladder pain syndrome/interstitial cystitis (BPS/IC) patients and to investigate if chronic adrenergic stimulation in intact rats induces BPS/IC-like bladder modifications. METHODS: Clinical study--In BPS/IC patients and aged and body mass index matched volunteers TILT test was undertaken and catecholamines were measured in plasma and 24 hr urine samples. Experimental study--Phenylephrine was injected subcutaneously (14 days) to female Wistar rats. Pain behavior, spinal Fos expression, urinary spotting, number of fecal pellets expelled, frequency of reflex bladder contractions, and urothelial height were analyzed. Urothelium permeability was investigated by trypan blue staining. Immunoreactivity against caspase 3 and bax were studied in the urothelium and against alpha-1-adrenoreceptor and TRPV1 in suburothelial nerves. Mast cell number was determined in the sub-urothelium. In rats with lipopolysaccharide-induced cystitis, urinary catecholamines, and Vesicular Monoamine Transporter 2 (VMAT2) expression in bladder nerves were analyzed. RESULTS: The TILT test showed an increase of sympathetic activity. Noradrenaline levels in blood at resting conditions and in 24-hr urine samples were higher in BPS/IC patients. Phenylephrine administration increased visceral pain, spinal Fos expression, bladder reflex activity, urinary spotting and the number of expelled fecal pellets. The mucosa showed urothelial thinning and increased immunoreactivity for caspase 3 and bax. Trypan blue staining was only observed in phenylephrine treated animals. Suburothelial nerves co-expressed alpha1 and TRPV1. Mastocytosis was present in the suburothelium. Cystitis increased sympathetic nerve density and urinary noradrenaline levels. CONCLUSIONS: Excessive adrenergic stimulation of the bladder may contribute to the pathophysiological mechanisms of BPS/IC.

Detrusor Overactivity After Partial Bladder Outlet Obstruction Is Associated With High Urinary Adenosine Triphosphate Levels in Female Wistar Rats.

PURPOSE: Bladder outlet obstruction (BOO) commonly causes detrusor overactivity (DO). In this study, a post hoc analysis of previous obtained data, we investigate if DO occurring in initial phases of BOO is associated with changes in urinary adenosine triphosphate (ATP) levels. METHODS: Adult female Wistar rats were submitted to partial BOO (pBOO) or to sham obstruction. Cystometry was performed at 3 or 15 days after pBOO and saline voided was collected for ATP determination. Normality was tested using Shapiro-Wilk test. The mean frequency of voiding contractions (VCs) of the sham-operated animals at 15 days after surgery, plus or minus 3 standard deviations, was used to represent the normal range. Statistical analyses were performed using the chi-square and Mann-Whitney tests. RESULTS: DO was indicated by a VC frequency greater than or equal to 0.9 VCs/min. DO was observed in 63% of animals at 3 days and in 33% at 15 days following pBOO. ATP levels were significantly higher in rats with DO compared to those without DO. CONCLUSION: The DO phenotype, occurring in the initial phases of BOO, is associated with comparatively high urinary ATP levels.

The Ketone Bridge Between the Heart and the Bladder: How Fast Should We Go?

Metabolic syndrome (MS) is associated with both cardiovascular and bladder dysfunction. Insulin resistance (IR) and central obesity, in particular, are the main risk factors. In these patients, vicious pathological cycles exacerbate abnormal carbohydrate metabolism and sustain an inflammatory state, with serious implications for both the heart and bladder. Ketone bodies serve as an alternative energy source in this context. They are considered a "super-fuel" because they generate adenosine triphosphate with less oxygen consumption per molecule, thus enhancing metabolic efficiency. Ketone bodies have a positive impact on all components of MS. They aid in weight loss and glycemic control, lower blood pressure, improve lipid profiles, and enhance endothelial function. Additionally, they possess direct anti-inflammatory, antioxidant, and vasodilatory properties. A shared key player in dysfunction of both the heart and bladder dysfunction is the formation of the NLRP3 inflammasome, which ketone bodies inhibit. Interventions that elevate ketone body levels-such as fasting, a ketogenic diet, ketone supplements, and sodium-glucose cotransporter 2 inhibitors-have been shown to directly affect cardiovascular outcomes and improve lower urinary tract symptoms derived from MS. This review explores the pathophysiological basis of the benefits of ketone bodies in cardiac and bladder dysfunction.

The Unmet Needs for Studying Chronic Pelvic/Visceral Pain Using Animal Models.

The different definitions of chronic pelvic/visceral pain used by international societies have changed over the years. These differences have a great impact on the way researchers study chronic pelvic/visceral pain. Recently, the role of systemic changes, including the role of the central nervous system, in the perpetuation and chronification of pelvic/visceral pain has gained weight. Consequently, researchers are using animal models that resemble those systemic changes rather than using models that are organ- or tissue-specific. In this review, we discuss the advantages and disadvantages of using bladder-centric and systemic models, enumerating some of the central nervous system changes and pain-related behaviors occurring in each model. We also present some drawbacks when using animal models and pain-related behavior tests and raise questions about possible, yet to be demonstrated, investigator-related bias. We also suggest new approaches to study chronic pelvic/visceral pain by refining existing animal models or using new ones.

Comprehensive quantitative sensory testing shows altered sensory function in women with chronic pelvic pain: results from the Translational Research in Pelvic Pain (TRiPP) Study.

ABSTRACT: Chronic pelvic pain (CPP), despite its high prevalence, is still relatively poorly understood mechanistically. This study, as part of the Translational Research in Pelvic Pain (TRiPP) project, has used a full quantitative sensory testing (QST) paradigm to profile n = 85 women with and without CPP (endometriosis or bladder pain specifically). We used the foot as a control site and abdomen as the test site. Across 5 diagnostically determined subgroups, we found features which are common across different aetiologies, eg, gain of function in pressure pain threshold (PPT) when assessing responses from the lower abdomen or pelvis (referred pain site). However, disease-specific phenotypes were also identified, eg, greater mechanical allodynia in endometriosis, despite there being large heterogeneities within diagnostic groups. The most common QST sensory phenotype was mechanical hyperalgesia (>50% across all the groups). A "healthy' sensory phenotype was seen in <7% of CPP participants. Specific QST measures correlated with sensory symptoms assessed by the painDETECT questionnaire (pressure-evoked pain [painDETECT] and PPT [QST] [ r = 0.47, P < 0.001]; mechanical hyperalgesia (painDETECT) and mechanical pain sensitivity [MPS from QST] [ r = 0.38, P = 0.009]). The data suggest that participants with CPP are sensitive to both deep tissue and cutaneous inputs, suggesting that central mechanisms may be important in this cohort. We also see phenotypes such as thermal hyperalgesia, which may be the result of peripheral mechanisms, such as irritable nociceptors. This highlights the importance of stratifying patients into clinically meaningful phenotypes, which may have implications for the development of better therapeutic strategies for CPP.

Transient receptor potential vanilloid 1 mediates nerve growth factor-induced bladder hyperactivity and noxious input.

OBJECTIVES: To explore the role of transient receptor potential vanilloid 1 (TRPV1) in the excitatory effects of chronic administration of nerve growth factor (NGF) on bladder-generated sensory input and reflex activity. To explore new therapeutic targets for bladder dysfunction. MATERIALS AND METHODS: Wild-type (WT) and TRPV1 knockout (KO) mice received daily intraperitoneal injections of NGF (1 µg/10 g) or saline for a period of 4 days, during which time thermal sensitivity was evaluated daily. On the 5th day, mice were anaesthetized and cystometries were performed. The frequency, amplitude and area under the curve (AUC) of bladder reflex contractions were determined. c-Fos expression was evaluated on L6 spinal cord sections of WT and TRPV1 KO mice treated with saline or chronic NGF by immunohistochemistry. TrkA receptor staining intensity was determined in L6 spinal cord sections and respective dorsal root ganglia of WT and TRPV1 KO mice. RESULTS: Repeated administration of NGF induced thermal hypersensitivity in WT but not in TRPV1 KO mice. The frequency of bladder contractions of saline-treated WT and TRPV1 KO mice was similar, the values respectively being 0.45 ± 0.12/min and 0.46 ± 0.16/min. Treatment with NGF enhanced bladder reflex activity in WT mice to 1.23 ± 0.41/min (P < 0.05). In NGF-treated KO mice, the frequency of bladder contractions was 0.60 ± 0.05/min. Irrespective of treatment, no differences were observed in the amplitude of bladder contractions of WT and TRPV1 KO mice. The AUC was significantly increased in NGF-treated WT-mice, when compared with saline-treated WT-mice. No changes were found in AUC of saline-treated and NGF-treated TRPV1 KO mice. Chronic administration of NGF resulted in a significant increase of spinal c-Fos expression in WT mice (P < 0.05 vs KO animals), but not in TRPV1 KO animals. TrkA expression was similar in WT and TRPV1 KO mice. CONCLUSIONS: NGF-induced bladder overactivity and noxious input depend on the interaction of NGF with TRPV1. The lack of bladder overactivity in TRPV1 KO mice treated with NGF does not represent loss of TrkA expression. TRPV1 is essential for NGF-driven bladder dysfunction and represents a bottleneck target in bladder pathologies associated with NGF up-regulation.

Expression of apoptosis-regulating genes in the rat prostate following botulinum toxin type A injection.

BACKGROUND: Onabotulinumtoxin A (OnabotA) injection has been investigated as a novel treatment for benign prostatic enlargement caused by benign prostatic hyperplasia. An OnabotA-induced volume reduction caused by sympathetic fibers impairment has been proposed as a potential mechanism of action. Our aim was to investigate the expression of apoptosis-regulating proteins in the rat prostate following OnabotA intraprostatic injection. METHODS: Adult Wistar rats were injected in the ventral lobes of the prostate with 10 U of OnabotA or saline. A set of OnabotA-injected animals was further treated with 0.5 mg/kg of phenylephrine (PHE) subcutaneously daily. All animals were sacrificed after 1 week and had their prostates harvested. Immunohistochemical staining was performed for Bax, Bcl-xL and caspase-3 proteins and visualized by the avidin-biotin method. The optical density of the glandular cells was also determined, with measurement of differences between average optical densities for each group. RESULTS: Saline-treated animals showed intense epithelial staining for Bcl-xL and a faint labelling for both Bax and Caspase-3. OnabotA-treated rats showed a reduced epithelial staining of Bcl-xL and a consistently increased Bax and Caspase-3 staining when compared with saline-treated animals. PHE-treated animals showed a stronger Bcl-xL staining and reduced staining of both Bax and Caspase-3 when compared to the OnabotA group. Mean signal intensity measurements for each immunoreaction confirmed a significant decrease of the signal intensity for Bcl-xL and a significant increase of the signal intensity for Bax and Caspase 3 in OnabotA-injected animals when compared with the control group. In OnabotA+PHE treated animals mean signal intensity for Bcl-xL, Bax and Caspase 3 immunoreactions was identical to that of the control animals. CONCLUSIONS: These results support the hypothesis that OnabotA activates apoptotic pathways in the rat prostate through a mechanism that involves sympathetic outflow impairment.

The Role of Urinary VEGF in Observational Studies of BPS/IC Patients: A Systematic Review.

BACKGROUND: Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic pain condition, often underdiagnosed, with an important impact on patient quality of life. More recently, an association between VEGF and its receptors has been suggested in BPS/IC pathophysiology, due to their role in promoting angiogenesis and inflammation, which can enhance bladder pain. Eventually, VEGF may be used as a biomarker for the diagnosis and prognostication of BPS/IC. To further clarify this issue, this review aims to critically summarize the available information, giving rise to a solid starting point for future studies. METHODS: We systematically searched PubMed and Embase, using the queries "urinary VEGF", "urinary VEGF" AND "pain", "urinary VEGF" AND "lower urinary tract symptoms" and "urinary VEGF" AND "LUTS" from January 2016 to February 2022. RESULTS: A total of 1026 papers were identified from which 7 articles were included in this study, which assessed 1036 participants. Regarding VEGF levels, overactive bladder (OAB) and healthy patients were used for comparison with BPS/IC patients. VEGF concentration seems to be higher when compared to healthy patients and overactive bladder (OAB) patients. Higher levels of VEGF were associated with pain severity, while a decrease in VEGF concentration was associated with pain and symptom improvement in women. However, these findings were not constant in all studies. CONCLUSIONS: There is a trend toward a relevant association between increased VEGF levels and pain or symptom severity in BPS/IC patients. Although there are some discrepancies among the studies and the number of patients included is small, VEGF and its receptors should be considered for future studies regarding its use in BPS/IC pathophysiology, diagnosis and prognostication.

Myogenic Underactive Bladder and Heart Failure Resemblance: A Novel Role for SGLT2 Inhibition?

The heart and bladder share physiological biomechanical determinants of contraction. Heart failure (HF) and myogenic underactive bladder (mUAB) also share similarities in their pathophysiology. In both cases there is muscle injury that is directly linked to disease stage. In the final stage, both myocardium and detrusor show marked fibrosis and lower contractility. While HF has an established pharmacological treatment, there are still no effective drugs for mUAB. This mini-review explores the similarities between HF and mUAB and suggests that, as in HF, SGLT2 inhibitors may also have a beneficial role in mUAB. PATIENT SUMMARY: To date, there is no treatment for underactive bladder caused by problems with the bladder muscle (mUAB). We review similarities between this condition and heart failure and hypothesize that a recent drug class with striking results in heart failure might also have a beneficial role in mUAB.

Silodosin Improves Pain and Urinary Frequency in Bladder Pain Syndrome/Interstitial Cystitis Patients.

Purpose: Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) is a bladder-related chronic inflammatory disease. Data indicate that stress enhances the excitability of bladder nociceptors through the stimulation of alpha1A-adrenoceptors. Stress is known to play a crucial role in BPS/IC patients. We aimed to assess the efficacy and safety of daily silodosin in refractory BPS/IC female patients and its correlation with stress coping. Materials and Methods: An open-label trial was conducted with 20 refractory BPS/IC patients. Evaluations occurred at baseline and the 8th and 12th weeks. Primary endpoint was bladder pain evaluated by visual analogue scale (VAS). Secondary endpoints included daily frequency, nocturia and maximum voided volume obtained from a 3-day bladder diary, the O'Leary−Sant Symptom Score, and two questions accessing stress coping. Patients initiated daily doses of 8 mg silodosin, which could be titrated to 16 mg. Median values with percentiles 25 and 75 (25; 75) were used. Wilcoxon signed-rank test was used for comparisons. A minimally important difference of 3 points for pain was established to define clinically relevant improvement. Results: Median age was 56 years. Median pain score decreased from 8.00 (6.00; 8.00) at baseline to 4.00 (2.00; 5.50) (p < 0.001), meaning that the primary endpoint was reached. Total urinary frequency decreased from 14.00 (13.00; 21.00) to 9.00 (7.50; 11.00) (p < 0.05), and all the other secondary endpoints also showed a statistically significant improvement. Eleven patients improved by ≥3 pain points in VAS, meaning that 65% of patients that ended the study protocol achieved clinical significant improvement or, in the full analysis set, that 55% of the 20 initial patients improved significantly. Fourteen (82%) decreased by ≥2 micturitions/day. Overall, the cohort's stress coping was low. Conclusions: Silodosin can be an effective and well-tolerated treatment for refractory BPS/IC female patients.

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.

Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A.

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

Preclinical models of endometriosis and interstitial cystitis/bladder pain syndrome: an Innovative Medicines Initiative-PainCare initiative to improve their value for translational research in pelvic pain.

ABSTRACT: Endometriosis (ENDO) and interstitial cystitis/bladder pain syndrome (IC/BPS) are chronic pain conditions for which better treatments are urgently needed. Development of new therapies with proven clinical benefit has been slow. We have conducted a review of existing preclinical in vivo models for ENDO and IC/BPS in rodents, discussed to what extent they replicate the phenotype and pain experience of patients, as well as their relevance for translational research. In 1009 publications detailing ENDO models, 41% used autologous, 26% syngeneic, 18% xenograft, and 11% allogeneic tissue in transplantation models. Intraperitoneal injection of endometrial tissue was the subcategory with the highest construct validity score for translational research. From 1055 IC/BPS publications, most interventions were bladder centric (85%), followed by complex mechanisms (8%) and stress-induced models (7%). Within these categories, the most frequently used models were instillation of irritants (92%), autoimmune (43%), and water avoidance stress (39%), respectively. Notably, although pelvic pain is a hallmark of both conditions and a key endpoint for development of novel therapies, only a small proportion of the studies (models of ENDO: 0.5%-12% and models of IC/BPS: 20%-44%) examined endpoints associated with pain. Moreover, only 2% and 3% of publications using models of ENDO and IC/BPS investigated nonevoked pain endpoints. This analysis highlights the wide variety of models used, limiting reproducibility and translation of results. We recommend refining models so that they better reflect clinical reality, sharing protocols, and using standardized endpoints to improve reproducibility. We are addressing this in our project Innovative Medicines Initiative-PainCare/Translational Research in Pelvic Pain.

Understanding underactive bladder: a review of the contemporary literature.

Underactive bladder (UAB) is characterized by prolonged voiding, hesitancy, and slow and/or intermittent stream with or without a sensation of incomplete bladder emptying. The overlap of UAB lower urinary tract symptoms with those of overactive bladder or bladder outlet obstruction, as well as its multifactorial etiology, make UAB study, as well as its diagnosis and management, a very arduous and challenging task. Therefore, despite its incidence and significant impact in the quality of life of both men and women, UAB remains a poorly understood urologic condition with insufficient and ineffective treatment options available. In this review, we will focus on the etiology theories that have been proposed and the animal models available to test those theories.

Fatty acid amide hydrolase inhibition normalises bladder function and reduces pain through normalising the anandamide/palmitoylethanolamine ratio in the inflamed bladder of rats.

Fatty acid amide hydrolase inhibition may be used to control bladder function and pain by modulating endocannabinoid levels in cystitis. We studied the effect of the peripherally restricted fatty acid amide hydrolase inhibitor URB937 in bladder reflex activity and bladder pain using the lipopolysaccharide model of cystitis. We also correlated the URB937's effects with tissue levels of the endocannabinoids anandamide and palmitoylethanolamine. URB937 did not change the reflex activity of normal bladders. In inflamed bladders, URB937 had a U-shaped dose-response curve; following an initial cannabinoid receptor type 1-mediated reduction in pain responses and normalisation of bladder reflex activity, URB937 gradually increased both pain responses and bladder reflex activity through the transient receptor potential ion channel subfamily V member 1. Chronic cystitis increased the tissue levels of anandamide and decreased those of palmitoylethanolamine. At the dose that normalised bladder reflex activity and decreased pain responses, URB937 normalised the levels of anandamide and palmitoylethanolamine in the bladder. At high doses that induced excitatory effects, URB937 apparently did not change anandamide and palmitoylethanolamine levels, which therefore were in the range of the inflamed bladder. Fatty acid amide hydrolase inhibition results in complex changes in bladder endocannabinoid levels. The therapeutic effect of fatty acid amide hydrolase inhibitors is not related to increase in anandamide levels but rather a normalisation of the anandamide and palmitoylethanolamine level ratio.