Interstitial cystitis: a critique of current concepts with a new proposal for pathologic diagnosis and pathogenesis

A Bibliometric Analysis of Urologic Chronic Pelvic Pain Syndrome From 2000 to 2022

Purpose

Urologic chronic pelvic pain syndrome has attracted a lot of attention in the new century, and an increasing number of relevant studies have been published. Therefore, we performed a bibliometric analysis of these publications, hoping to show the current research hotspots and future research trends.

Methods

The articles on were selected from the Web of Science Core Collection. Countries, authors, references and keywords in the field were visualized and analyzed using CiteSpace and VOSViewer software.

Results

A total of 1014 articles on urologic chronic pelvic pain syndrome were identified, with "chronic pelvic pain syndrome" being the most common keyword, with a strong association with "interstitial cystitis" and "chronic prostatitis". The hotspot of urologic chronic pelvic pain syndrome research has gradually shifted from chronic prostatitis / urologic chronic pelvic pain syndrome to cystitis/bladder pain syndrome over the past few years. Future research tends to focus on urologic chronic pelvic pain syndrome etiology, including oxidative stress and inflammation.

Conclusion

Research on urologic chronic pelvic pain syndrome is steadily growing. The United States has made the most prominent contribution in this area, and the share of China's contribution is expected to grow further. The etiology of urologic chronic pelvic pain syndrome, including inflammation and oxidative stress, have been the focus of current research and developmental trends in the future research.

Current Understanding of the Pathophysiology and Novel Treatments of Interstitial Cystitis/Bladder Pain Syndrome

The pathophysiology of interstitial cystitis/bladder pain syndrome (IC/BPS) is multifactorial. Identifying the clinical characteristics and cystoscopic findings of bladder-centered IC/BPS facilitates optimal treatment strategies targeting the diseased urinary bladder. Patients with Hunner’s lesion (HIC) and without Hunner’s lesion (NHIC) should be treated differently. Based on the histopathological findings, NHIC can be treated with intravesical instillation of urothelial protective agents, such as hyaluronic acid, to cover the urothelial defects. In non-responders, chronic inflammation and higher urothelial dysfunction can be treated with intravesical botulinum toxin A injection, platelet-rich plasma injection, or low-energy shock wave treatment to reduce inflammation, increase tissue regeneration, and improve the urothelial barrier. Patients with HIC should be treated with electrocauterization first; augmentation enterocystoplasty should only be used in end-stage HIC when the contracted bladder is refractory to other treatments. The antiviral agent, valacyclovir, can be used in patients with HIC, small bladder capacity, and high-grade glomerulations. In addition, behavioral modification is always recommended from the beginning of treatment. Treatment with cognitive behavioral therapy interventions in combination with bladder therapy can reduce anxiety and improve treatment outcomes. Herein, recent advances in the pathophysiology and novel treatments for IC/BPS are reviewed.

Prevalence, Risk Factors, Pathophysiology, Potential Biomarkers and Management of Feline Idiopathic Cystitis: An Update Review

Feline idiopathic cystitis is a widespread disease in small animal clinics, which mainly presents with urinary signs like dysuria, stranguria, hematuria, pollakiuria, and periuria. The etiopathogenesis of the disease may involve interactions between the environmental stressors, neuroendocrine system and bladder of affected cats. Diagnostic biomarkers have not been tested in clinical studies though they are theoretically feasible, and since the clinical signs of the disease assemble those of other feline lower urinary diseases, its diagnosis is a procedure of exclusion. The primary treatment of the disease is long-term multimodal environmental modification (or enrichment) while anti-anxiety drugs and nutritional supplements are recommended for chronic recurrent cases. Still, many medicines need to be evaluated for their efficacy and safety. This review aims to provide readers with a comprehensive understanding of feline idiopathic cystitis by summarizing and updating studies concerning the prevalence, risk factors, etiological hypotheses, diagnostic procedures, possible treatments, and prognosis of the disease.

Temperature-responsive silk-elastinlike protein polymer enhancement of intravesical drug delivery of a therapeutic glycosaminoglycan for treatment of interstitial cystitis/painful bladder syndrome

Interstitial cystitis (IC), also known as painful bladder syndrome, is a debilitating chronic condition with many patients failing to respond to current treatment options. Rapid clearance, mucosal coating, and tight epithelium create strong natural barriers that reduce the effectiveness of many pharmacological interventions in the bladder. Intravesical drug delivery (IDD) is the administration of therapeutic compounds or devices to the urinary bladder via a urethral catheter. Previous work in improving IDD for IC has focused on the sustained delivery of analgesics within the bladder and other small molecule drugs which do not address underlying inflammation and bladder damage. Therapeutic glycosaminoglycans (GAG) function by restoring the mucosal barrier within the bladder, promoting healing responses, and preventing irritating solutes from reaching the bladder wall. There is an unmet medical need for a therapy that provides both acute relief of symptoms while alleviating underlying physiological sources of inflammation and promoting healing within the urothelium. Semi-synthetic glycosaminoglycan ethers (SAGE) are an emerging class of therapeutic GAG with intrinsic anti-inflammatory and analgesic properties. To reduce SAGE clearance and enhance its accumulation in the bladder, we developed a silk-elastinlike protein polymer (SELP) based system to enhance SAGE IDD. We evaluated in vitro release kinetics, rheological properties, impact on bladder function, pain response, and bladder inflammation and compared their effectiveness to other temperature-responsive polymers including Poloxamer 407 and poly(lactic-co-glycolic acid)-poly(ethylene glycol). SAGE delivered via SELP-enhanced intravesical delivery substantially improved SAGE accumulation in the urothelium, provided a sustained analgesic effect 24 h after administration, and reduced inflammation.

Variations in bladder pain syndrome/interstitial cystitis (IC) definitions, pathogenesis, diagnostics and treatment: a systematic review and evaluation of national and international guidelines

INTRODUCTION AND HYPOTHESIS

Interstitial cystitis (IC) and bladder pain syndrome (BPS) are challenging and encompassing hypersensitivity disorders of the lower urinary tract. A variety of national and international guidelines have been published including guidance on nomenclature, definitions, etiopathology, diagnostics and treatment. A lack of universally established clinical guidance is apparent. The aim of this review is to evaluate key guidelines on this area of practice, identify variations, compare their recommendations and grade them using AGREE II.

METHODS

Literature searches were performed using the PUBMED and CINAHL database from January 1, 1983, to December 1, 2018, referring to the search strategy of AUA. Ten national and international guidelines were included into the analysis. We assessed the guidelines with the updated AGREE II.

RESULTS

Symptoms congruent in all guidelines are: pain, pressure, discomfort and frequency, urgency and nocturia. Urinalysis is a prerequisite for diagnostics, cystoscopy for most and urodynamics not part of the routine assessment. Treatment options are recommended stepwise. The highest level of evidence and consensus was identified for oral therapies. Nine guidelines had an overall quality score ≥ 50% and three scored ≥ 70% (AUA, GG, RCOG).

CONCLUSIONS

The guidelines are congruent in symptom reporting, quite congruent in diagnostics and vary to a high degree on treatment recommendations. The complexity of BPS and emerging evidence indicate the need for regular updating of the guidelines and a wider consensus.

IL-33 mast cell axis is central in LL-37 induced bladder inflammation and pain in a murine interstitial cystitis model

Interstitial cystitis (IC), also known as painful bladder syndrome (PBS), is a debilitating chronic condition that afflicts over 3 million women above the age of 18 in the U.S., and most patients fail to respond to current treatment options. Mast cells have previously been implicated as both a diagnostic and prognostic marker in IC/PBS. Patients with IC/PBS have been shown to have elevated levels of IL-33, a cytokine released in response to tissue insult, in their urine. We hypothesize that mast cell-mediated inflammation induced from IL-33 may play an important role in initiating pain and inflammation in IC/PBS. A human cathelicidin, LL-37, which is found at elevated levels in IC/PBS patients, was used to induce an IC/PBS-like state of inflammation and bladder pain in mast cell deficient C-kit (-/-) and wild type C57Bl/6 (WT) mice. Inflammation was quantified using myeloperoxidase (MPO) expression in bladder tissues measured via ELISA. Response rate to suprapubic stimulation from von Frey filaments was used to assess the relative pain and discomfort. Both types of mice increased IL-33 expression in response to LL-37 exposure. However, mast cell deficient mice demonstrated significantly lower levels of inflammation (p < 0.001) and reduced pain response (p < 0.001) compared to WT mice. These findings implicate an IL-33-mast cell dependent axis with a potential etiology of pain and inflammation in IC/PBS. Future therapeutics aimed at targeting the IL-33 - mast cell axis could potentially serve as useful targets for treating IC/PBS.

Adelmidrol + sodium hyaluronate in IC/BPS or conditions associated to chronic urothelial inflammation. A translational study

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic bladder condition characterized by frequent urination, bladder inflammation and pain. It is a particular challenging disease and a clear unmet medical need in terms of identifying new therapeutic strategies. The aim of study was to evaluate the anti-inflammatory effects of intravesical Vessilen^® (a new formulation of 2% adelmidrol (the diethanolamide derivative of azelaic acid) + 0.1% sodium hyaluronate) administration in rodent models of IC/BPS and in IC/BPS patients or other bladder disorders. Acute and chronic animal models of cystitis were induced by a single or repetitive intraperitoneal injections of cyclophosphamide (CYP); patients with IC/BPS or with bladder pain syndrome associated with symptoms of the lower urinary tract treated once weekly by bladder instillation of Vessilen^® for 8 weeks. CYP instillation caused macroscopic and histological bladder alterations, inflammatory infiltrates, increased mast cell numbers, bladder pain, increased expression of nitrotyrosine, decreased expression of endothelial tight junction zonula occludens-1. Intravesical Vessilen® treatment was able to ameliorate CYP induced bladder inflammation and pain by inhibiting nuclear factor-κB pathway and inflammatory mediator levels as well as reduced mechanical allodynia and nerve growth factor levels. A significant improvement in quality of life and symptom intensity were evident in patients with IC/BPS or other bladder disorders treated with Vessilen^®. Vessilen^® could be a new therapeutic approach for human cystitis.

Animal Modelling of Interstitial Cystitis/Bladder Pain Syndrome

The etiology of interstitial cystitis/bladder pain syndrome (IC/BPS) remains elusive and may involve multiple causes. To better understand its pathophysiology, many efforts have been made to create IC/BPS models. Most existing models of IC/BPS strive to recreate bladder-related features by applying noxious intravesical or systemic stimuli to healthy animals. These models are useful to help understand various mechanisms; however, they are limited to demonstrating how the bladder and nervous system respond to noxious stimuli, and are not representative of the complex interactions and pathophysiology of IC/BPS. To study the various factors that may be relevant for IC/BPS, at least 3 different types of animal models are commonly used: (1) bladder-centric models, (2) models with complex mechanisms, and (3) psychological and physical stressors/natural disease models. It is obvious that all aspects of the human disease cannot be mimicked by a single model. It may be the case that several models, each contributing to a piece of the puzzle, are required to recreate a reasonable picture of the pathophysiology and time course of the disease(s) diagnosed as IC/BPS, and thus to identify reasonable targets for treatment.

Acyloxyacyl hydrolase modulates pelvic pain severity

Chronic pelvic pain causes significant patient morbidity and is a challenge to clinicians. Using a murine neurogenic cystitis model that recapitulates key aspects of interstitial cystitis/bladder pain syndrome (IC), we recently showed that pseudorabies virus (PRV) induces severe pelvic allodynia in BALB/c mice relative to C57BL/6 mice. Here, we report that a quantitative trait locus (QTL) analysis of PRV-induced allodynia in F2_CxB progeny identified a polymorphism on chromosome 13, rs6314295 , significantly associated with allodynia (logarithm of odds = 3.11). The nearby gene encoding acyloxyacyl hydrolase ( Aoah) was induced in the sacral spinal cord of PRV-infected mice. AOAH-deficient mice exhibited increased vesicomotor reflex in response to bladder distension, consistent with spontaneous bladder hypersensitivity, and increased pelvic allodynia in neurogenic cystitis and postbacterial chronic pain models. AOAH deficiency resulted in greater bladder pathology and tumor necrosis factor production in PRV neurogenic cystitis, markers of increased bladder mast cell activation. AOAH immunoreactivity was detectable along the bladder-brain axis, including in brain sites previously correlated with human chronic pelvic pain. Finally, AOAH-deficient mice had significantly higher levels of bladder vascular endothelial growth factor, an emerging marker of chronic pelvic pain in humans. These findings indicate that AOAH modulates pelvic pain severity, suggesting that allelic variation in Aoah influences pelvic pain in IC.

Pathomechanism of Interstitial Cystitis/Bladder Pain Syndrome and Mapping the Heterogeneity of Disease

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a heterogeneous syndrome which is usually characterized by urinary frequency, nocturia, and bladder pain. Several pathomechanisms have been proposed, including uroepithelial dysfunction, mast cell activation, neurogenic inflammation, autoimmunity, and occult urinary tract infections. It is possible that an inflammatory process alters regulation of urothelial homeostasis and results in dysfunction of the bladder epithelium. Different phenotypes of IC/BPS have been explored including Hunner and non-Hunner type IC, hypersensitive bladder, and bladder pain both with and without functional somatic syndrome. Different gene expressions have also been found in different IC phenotypes. Abnormal expressions of uroplakin, chondroitin sulfate and adhesive protein E-cadherin, tight junction protein zonula occludens-1 in IC/BPS bladder suggest abnormal epithelial differentiation in this bladder disease. Analysis of inflammatory proteins, or cytokines in the urine or serum provides another diagnostic foundation forIC/BPS subtypes. The involvement of IC/BPS in systemic functional somatic syndrome and other pelvic organ diseases might also subdivide subtypes of IC/BPS. Chronic inflammation, increased urothelial apoptosis, and abnormal urothelial function are closely associated in IC bladders. This article reviews recent research on the pathomechanisms of IC, which might help us in mapping the heterogeneity of the disease.

Oral glucosamine and the management of feline idiopathic cystitis

Oral glucosamine was compared to a placebo for the management of cats with feline idiopathic cystitis (FIC) in a randomised, double-blinded, placebo-controlled, study. Forty cats with a history of recurrent cystitis due to FIC were divided into two groups and treated daily per os with either 125 mg N-acetyl glucosamine or a placebo for six months. Owners graded their cats' clinical signs at the beginning and end of the study, and kept daily diaries documenting signs of cystitis using visual analogue scales. Further episodes of cystitis were seen in 26 (65%) of the cats during the study. Affected cats experienced a mean of five recurrences (range 1–19) with each recurrence lasting a mean of four days (range 1–64 days).

There were no significant differences between the two groups when considering the owners assessments of the mean health score ( P > 0.5), the average monthly clinical score ( P = 0.22) or the average number of days with clinical signs ( P = 0.28). Two cats suffered from such severe recurrent urethral obstruction that they were euthanased; they were both in the placebo group. Compared to the start of the study the majority of cats in both groups improved significantly ( P < 0.001) (mean health score of each group at the start was 0.5 ± SD 0.5, compared to glucosamine 4.4 ± 0.7 and placebo 3.9 ± 1.6 at the end). This is believed to have occurred because the owners of 36 of the 40 cats (90%) started feeding more canned cat food. The urine specific gravity at the start of the trial was significantly higher (mean 1.050 ± SD 1.007) than when reassessed one month later (1.036 ± 1.010, P < 0.01).

A pilot study using synthetic feline facial pheromone for the management of feline idiopathic cystitis

Synthetic feline facial pheromone (FFP) (Feliway; Ceva Animal Health) was assessed for the management of cats with recurrent feline idiopathic cystitis (FIC). Nine of 12 cats completed the randomised, double-blinded, placebo-controlled, crossover pilot study. They had their environment treated daily with either FFP or placebo for 2 months, after which time the treatment groups were reversed. Owners used visual analogue scales to define the severity of their cat's clinical signs and behavioural changes. Five (56%) of the owners stated that their cat's overall health was better when they were using FFP. Four (44%) of the owners noticed no difference between when using the FFP and when using the placebo. While there were no statistical differences between the two treatment groups there was a trend for the cats exposed to FFP to show fewer days with clinical signs of cystitis (FFP total, mean per cat±standard deviation, 30, 4.3±6.7; placebo 69, 9.9±19.1), a lower overall clinical score (1667, 238±476; 2009, 287±425), a reduced number of episodes of cystitis (9, 1.3±2.0; 10, 1.4±2.1) and reduced negative behavioural traits (e.g., less aggression and fear) (−128, −18.3±65.8; −73, −10.4±35.1).

Sympathetic nervous system and chronic bladder pain: a new tune for an old song

Chronic bladder pain (CBP) patients present with pelvic pain or discomfort during bladder filling, for at least a period of 6 months, which may be accompanied by lower urinary tract symptoms such as frequency, nocturia, and urgency. However, both the etiology of CBP and pathophysiological mechanisms are not well described. A number of clinical and basic animal model findings support involvement of sympathetic nervous system in chronic pain syndromes such as CBP. Examples include sympathetic overactivity and high plasma or urinary catecholamine levels that have a high correlation with nociceptive symptoms. In this review, we explored the current evidence in support of the involvement of sympathetic overactivity in CBP. As bladder inflammation often occurs among subgroups of CBP patients, we discuss the possible role of sympathetic nervous system in mastocytosis as well examples examples of animal models that further support the involvement of sympathetic dysfunction in CBP. As there is substantive evidence for cross-organ sensitization in the pelvis can lead to co-morbidity of genitourinary and gastrointestinal dysfunctions, we also include how sympathetic dysfunction may play a role in a number of co-morbid chronic pain syndromes.

Recommendations for the Diagnosis and Management of Bladder Pain Syndrome. Spanish Urological Association Consensus Document

INTRODUCTION

Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) and other bladder pathologies share common manifestations, such as the presence of mictional symptoms and a negative impact on the patient's quality of life. To be properly diagnosed and clinically managed, it is important to distinguish between its clinical modalities and diagnostic criteria for adequate exclusion.

OBJECTIVE

The purpose of this study was to standardize criteria for making decisions in BPS management, for its diagnosis, initial treatment and follow-up.

MATERIAL AND METHOD

A nominal group methodology was employed, using scientific evidence on BPS taken from a systematic (non-exhaustive) literature review for developing recommendations along with specialist expert opinions.

RESULTS

The diagnosis of BPS should be made based on the patient's clinical history, with emphasis on pain and mictional symptoms as well as excluding other pathologies with similar symptomatology. BPS treatment should be directed towards restoring normal bladder function, preventing symptom relapse and improving patients' quality of life. It is therefore advisable to start with conservative treatment and to adopt less conservative treatments as the level of clinical severity increases. It is also recommended to abandon ineffective treatments and reconsider other therapeutic options.

CONCLUSIONS

Quickly identifying the pathology is important when trying to positively influence morbidity and care quality for these patients.

Intracellular Bacterial Communities: A Potential Etiology for Chronic Lower Urinary Tract Symptoms

Patients with persistent lower urinary tract symptoms and negative urine cultures are often difficult to treat. Infection may go undetected in these patients because the concentrations of bacteria in their urine are beneath the threshold of standard urine culture techniques. Empiric treatment may result in temporary relief, followed by recurrent symptoms. Occult and recurrent urinary tract infection may be due to both invasion of the bladder wall by uropathogenic Escherichia coli and the formation of biofilm-like intracellular bacterial communities. This review examines emerging evidence for a role of intracellular bacterial communities in human infection.

Evaluation of Percutaneous Tibial Nerve Stimulation for Treatment of Refractory Painful Bladder Syndrome

OBJECTIVE

To evaluate the efficacy of intermittent percutaneous tibial nerve stimulation (PTNS) as a treatment modality for patients with refractory interstitial cystitis/bladder pain syndrome (IC/BPS).

PATIENTS AND METHODS

Twenty female patients with IC/BPS (mean symptom duration of 4.5 ± 2.4 years) each had a 30-minute session of PTNS per week for 12 successive weeks and the symptoms were assessed before, during, and after the treatment sessions by voiding diary, visual analog scale (VAS) for pain, interstitial cystitis symptom and problem indices (ICSI and ICPI), and global response assessment (GRA) scale. The scores of the previous questionnaires were evaluated at weeks 0, 6, and 12.

RESULTS

At week 0, the VAS, day time frequency, nocturia, and average voiding volume were 5.6 ± 1.1, 14.5 ± 4.0, 3.0 ± 0.9, and 131.8 ± 35.3 mL, respectively, meanwhile at week 12 these scores were 5.2 ± 1.5, 12.15 ± 3.7, 2.6 ± 0.7, and 141.0 ± 36.2, respectively. There was no statistically significant difference between the scores of the ICPI between weeks 0, 6, and 12 (P = .937). As regards the GRA score after the 12th session, 17 patients (85%) reported having no effect, 1 patient (5%) reported as having worse symptoms, and 2 patients (10%) reported having a mild good response.

CONCLUSION

Intermittent PTNS is not a satisfactory treatment for refractory IC/BPS. However, it is recommended to perform more studies with other treatment protocol (maybe closer sessions) to confirm these results.

Beyond a Simple Anesthetic Effect: Lidocaine in the Diagnosis and Treatment of Interstitial Cystitis/bladder Pain Syndrome

Intravesical local anesthetics, in a wide variety of combinations, are increasingly used to treat patients with interstitial cystitis-bladder pain syndrome (IC/BPS). Lidocaine has demonstrated properties that block the neuroinflammatory cycle associated with IC/BPS at many of the interactive points in this cycle. Intravesical lidocaine has been shown to assist in identifying the bladder as the source of pain in patients with pelvic pain. An appreciation of these anti-inflammatory effects and of the pharmacokinetics of intravesical lidocaine in patients with IC/BPS could lead to a safe and effective diagnosis and treatment for an as yet unidentified subset of patients in the IC/BPS spectrum.

Melatonin treatment further improves adipose-derived mesenchymal stem cell therapy for acute interstitial cystitis in rat

This study tests the hypothesis that combined melatonin and adipose-derived mesenchymal stem cell (ADMSC, 1.2 × 10(6) given intravenously) treatment offer superior protection against cyclophosphamide (CYP 150 mg/kg)-induced acute interstitial cystitis (AIC) in rats. Male adult Sprague-Dawley rats were treated as follows: sham controls, AIC alone, AIC + melatonin, AIC + ADMSC, and AIC + melatonin +ADMSC. When melatonin was used, it was given as follows: 20 mg/kg at 30 min after CYP and 50 mg/kg at 6 and 18 hr after CYP. Twenty-four-hour urine volume, urine albumin level, and severity of hematuria were highest in AIC rats and lowest in the controls; likewise urine volume was higher in AIC + melatonin rats than in AIC + ADMSC and AIC + melatonin + ADMSC treated rats; in all cases, P < 0.001. The numbers of CD14+, CD74+, CD68+, MIP+, Cox-2+, substance P+, cells and protein expression of IL-6, IL-12, RANTES, TNF-α, NF-κB, MMP-9, iNOS (i.e. inflammatory biomarkers), glycosaminoglycan level, expression of oxidized protein, and protein expression of reactive oxygen species (NOX-1, NOX-2, NOX-4) in the bladder tissue exhibited an identical pattern compared with that of hematuria among the five groups (all P < 0.0001). The integrity of epithelial layer and area of collagen deposition displayed an opposite pattern compared to that of hematuria among all groups (P < 0.0001). The cellular expressions of antioxidants (GR, GPx, HO-1, NQO 1) showed a significant progressive increase form controls to AIC + melatonin + ADMSC (all P < 0.0001). Combined regimen of melatonin and ADMSC was superior to either alone in protecting against CYP-induced AIC.

Brain-derived neurotrophic factor in urinary continence and incontinence

Urinary incontinence adversely affects quality of life and results in an increased financial burden for the elderly. Accumulating evidence suggests a connection between neurotrophins, such as brain-derived neurotrophic factor (BDNF), and lower urinary tract function, particularly with regard to normal physiological function and the pathophysiological mechanisms of stress urinary incontinence (SUI) and bladder pain syndrome/interstitial cystitis (BPS/IC). The interaction between BDNF and glutamate receptors affects both bladder and external urethral sphincter function during micturition. Clinical findings indicate reduced BDNF levels in antepartum and postpartum women, potentially correlating with postpartum SUI. Experiments with animal models demonstrate that BDNF is decreased after simulated childbirth injury, thereby impeding the recovery of injured nerves and the restoration of continence. Treatment with exogenous BDNF facilitates neural recovery and the restoration of continence. Serotonin and noradrenaline reuptake inhibitors, used to treat both depression and SUI, result in enhanced BDNF levels. Understanding the neurophysiological roles of BDNF in maintaining normal urinary function and in the pathogenesis of SUI and BPS/IC could lead to future therapies based on these mechanisms.

Pharmacokinetic considerations for therapies used to treat interstitial cystitis

INTRODUCTION

Interstitial cystitis (IC) or bladder pain syndrome (BPS) is defined as supra-pubic pain related to bladder filling. IC is characterized by a particular symptom complex with no identifiable causes; as with bladder hypersensitivity it is usually associated with urinary frequency and urgency with bladder pain. No current treatments have a significant impact on symptoms over time.

AREAS COVERED

This systematic review examines the pharmacokinetic aspects and adverse event of present IC therapy to highlight appropriate treatment to improve the symptoms of IC. This article reviews material obtained via Medline, PubMed, and EMBASE literature searches up to October 2013.

EXPERT OPINION

The correct approach to IC should consider a multidisciplinary team of specialists and a multimodal treatment package that include psychotherapy, behavior change, physical activation, and analgesic treatment. Unfortunately, a single therapeutic target for IC is not yet known. With regard to pathophysiology and therapy, there is more to discover. The first insult damages the bladder urothelium, hence vehicles that lead the drug to penetrate the wall of the bladder might be a novel strategic approach.

Tryptase activation of immortalized human urothelial cell mitogen-activated protein kinase

The pathogenesis of interstitial cystitis/painful bladder syndrome (IC/PBS) is multifactorial, but likely involves urothelial cell dysfunction and mast cell accumulation in the bladder wall. Activated mast cells in the bladder wall release several inflammatory mediators, including histamine and tryptase. We determined whether mitogen-activated protein (MAP) kinases are activated in response to tryptase stimulation of urothelial cells derived from human normal and IC/PBS bladders. Tryptase stimulation of normal urothelial cells resulted in a 2.5-fold increase in extracellular signal regulated kinase 1/2 (ERK 1/2). A 5.5-fold increase in ERK 1/2 activity was observed in urothelial cells isolated from IC/PBS bladders. No significant change in p38 MAP kinase was observed in tryptase-stimulated normal urothelial cells but a 2.5-fold increase was observed in cells isolated from IC/PBS bladders. Inhibition of ERK 1/2 with PD98059 or inhibition of p38 MAP kinase with SB203580 did not block tryptase-stimulated iPLA₂ activation. Incubation with the membrane phospholipid-derived PLA₂ hydrolysis product lysoplasmenylcholine increased ERK 1/2 activity, suggesting the iPLA₂ activation is upstream of ERK 1/2. Real time measurements of impedance to evaluate wound healing of cell cultures indicated increased healing rates in normal and IC/PBS urothelial cells in the presence of tryptase, with inhibition of ERK 1/2 significantly decreasing the wound healing rate of IC/PBS urothelium. We conclude that activation of ERK 1/2 in response to tryptase stimulation may facilitate wound healing or cell motility in areas of inflammation in the bladder associated with IC/PBS.

Ca(2+)/calmodulin-dependent protein kinase II is associated with pelvic pain of neurogenic cystitis

Interstitial cystitis/painful bladder syndrome is a chronic bladder inflammatory disease of unknown etiology that is often regarded as a neurogenic cystitis. Interstitial cystitis is associated with urothelial lesions, voiding dysfunction, and pain in the pelvic/perineal area. In this study, we used a murine neurogenic cystitis model to identify genes participating in the development of pelvic pain. Neurogenic cystitis was induced by the injection of Bartha's strain of pseudorabies virus (PRV) into the abductor caudalis dorsalis (tail base) muscle of female C57BL/6J mice. Mice infected with PRV developed progressive pelvic pain. The sacral spinal cord was harvested on postinfection days (PID) 2 and 4, and gene expression was analyzed by microarrays and confirmed by quantitative RT-PCR. On PID 2, the overall expression profile was similar to that of uninfected sacral spinal cord; by PID 4, there were substantial differences in expression of multiple functional classes of genes, especially inflammation. Analysis of pain-signaling pathways at the dorsal horn suggested that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) contributes to neurogenic cystitis pelvic pain. Consistent with this, CaMKIIδ expression exhibited a mast cell-dependent increase in the sacral spinal cord at the mRNA level, and phospho-CaMKII immunoreactivity in the dorsal horn was increased on postinfection day (PID) 4 during PRV infection. Finally, intrathecal injection of the CaMKII inhibitor KN-93 attenuated the PRV pain response. These data suggest that CaMKII plays a functional role in pelvic pain due to neurogenic cystitis.

Autonomic response during bladder hydrodistention in patients with bladder pain syndrome

PURPOSE

We determined whether patients with bladder pain syndrome who have typical interstitial cystitis endoscopic findings, including glomerulations and/or Hunner ulcer, have a distinct autonomic response during bladder hydrodistention.

MATERIALS AND METHODS

Included in the study were 50 consecutive patients (40 females and 10 males) who met International Society for the Study of BPS recommendations. All patients underwent the same clinical evaluation, consisting of medical history, physical examination, urine and blood tests, urine cytology and culture, urinary tract ultrasound and urodynamics. Bladder hydrodistention and biopsies were performed using general anesthesia. Systolic and diastolic blood pressure, and heart rate were recorded after the induction of general anesthesia and at the end of the filling phase. Patients were divided into 2 groups, including patients with and without typical endoscopic findings, respectively. Clinical, histological and urodynamic variables, and autonomic parameters were compared between the 2 groups.

RESULTS

No significant differences in demographics, symptoms, pain severity, comorbidities, previous surgery, urodynamic variables, anesthetic bladder capacity or histological findings were found between the 2 groups. In patients with endoscopic findings average ± SD systolic and diastolic blood pressure increased by 25 ± 19 and 21 ± 12 mm Hg, respectively, and average heart rate increased by 12 ± 11 beats per minute. All hemodynamic changes were statistically significant (p <0.001). In patients without endoscopic findings a minor decrease in hemodynamic parameters was observed.

CONCLUSIONS

Patients with bladder pain syndrome who have typical interstitial cystitis findings on endoscopy show a marked autonomic response during bladder hydrodistention, consisting of an increase in heart rate, and systolic and diastolic blood pressure.

Role of mast cells in male chronic pelvic pain

PURPOSE

Chronic pelvic pain syndrome accounts for 90% of all chronic prostatitis but it has an unknown pathogenesis. We sought to understand the role of mast cells and nerve growth factor in chronic pelvic pain.

MATERIALS AND METHODS

Expressed prostatic secretions in men with chronic pelvic pain syndrome and controls were tested for mast cell tryptase and nerve growth factor. Mast cell number, activation status and nerve growth factor expression were examined in the NOD/ShiLtJ experimental autoimmune prostatitis model and in mast cell deficient KitW-sh/KitW-sh mice. Tactile allodynia was quantified using von Frey filaments as a measure of pelvic pain behavior. Inhibitors of mast cell degranulation, histamine receptor antagonists and anti-nerve growth factor neutralizing antibodies were tested to decrease pelvic pain behavior.

RESULTS

Men with chronic pelvic pain syndrome showed increased mast cell tryptase and nerve growth factor in expressed prostatic secretions. In the experimental autoimmune prostatitis model increased total and activated mast cells were observed in the prostate. Mast cell deficient KitW-sh/KitW-sh mice showed attenuated pelvic pain behavior but no difference in inflammatory infiltrates in the prostate from controls. Mice with experimental autoimmune prostatitis also demonstrated increased intraprostatic nerve growth factor compared to that of KitW-sh/KitW-sh mice. Treatment of experimental autoimmune prostatitis with a mast cell stabilizer combined with a histamine 1 receptor antagonist resulted in a synergistic decrease in chronic pelvic pain. In contrast, neutralization of nerve growth factor in vivo did not result in pain relief.

CONCLUSIONS

Results suggest that mast cells are important mediators of chronic pelvic pain in experimental autoimmune prostatitis cases. They may be potential targets for therapeutic intervention in men with chronic prostatitis/chronic pelvic pain syndrome.

Gender specific pelvic pain severity in neurogenic cystitis

PURPOSE

Interstitial cystitis/painful bladder syndrome is a chronic bladder inflammatory disease of unknown etiology that is often regarded as neurogenic cystitis. The condition is associated with focal inflammation, urothelial lesions, voiding dysfunction and pain in the pelvic/perineal area. Approximately 90% of patients with the condition are women, suggesting the possibility of hormonal involvement in interstitial cystitis/painful bladder syndrome symptoms. We examined the basis of gender specific pelvic pain in a murine model of neurogenic cystitis that recapitulates features of interstitial cystitis/painful bladder syndrome and in which pelvic pain is mediated by mast cell histamine.

MATERIALS AND METHODS

Murine neurogenic cystitis was induced by tail base inoculation of C57BL/6 or BALB/c mice with the Bartha strain of pseudorabies virus. Pelvic pain behavior was assessed by quantifying tactile allodynia in response to mechanical stimulation with von Frey filaments. Bladder mast cells were quantified by flow cytometry.

RESULTS

Female mice of each genetic background showed significantly greater pelvic pain behavior than males, although responses were greater in BALB/c females. Gender specific pelvic pain behavior did not correspond to increased bladder inflammation or barrier dysfunction. Modulating reproductive hormonal status by ovariectomy and subsequent estrogen replacement had no effect on the magnitude of pseudorabies virus induced pain. The number of mast cells was associated with pelvic pain severity in female mice but it did not correlate with gender specific pelvic pain.

CONCLUSIONS

These data suggest that pelvic pain in mice with murine neurogenic cystitis is mediated by gender specific responsiveness to mast cells while pelvic pain severity is modulated by genetic factors.

Leukotriene D4 receptor antagonist montelukast alleviates protamine sulphate-induced changes in rat urinary bladder

What's known on the subject? and What does the study add? The mastocytosis in detrusor muscle and the leaky epithelium in interstitial cystitis were the most studied features. In this study the leaky epithelium was shown using the ruthenium red staining in electron microscopy and uroplakin distribution in light microscopy besides the mast cell concentration in detrusor muscle using tryptase immunohistochemistry.

OBJECTIVE

• To study the effects of montelukast (ML), a leukotriene receptor antagonist which has been shown to be effective in inhibiting the action of cysteinyl-containing leukotrienes, on protamine sulphate (PS)-induced changes in rat urinary bladder.

MATERIALS AND METHODS

• Wistar female rats were catheterized and intravesically infused with PBS (control group) or PS (PS group) dissolved in PBS twice in 24 h. • In the PS-applied and ML-treated group (PS + ML group) after the 10 mg/kg PS instillation, ML was injected i.p. twice daily for 3 days. • The urinary bladder was investigated for general morphology under a light microscope. • Tryptase immunohistochemistry was used to observe mast cell distribution and activation. Uroplakin distribution was also identified with immunohistochemistry.

RESULTS

• Alterations of glycosaminoglycan (GAG) and urothelial permeability were seen with ruthenium red (RR) staining techniques under a transmission electron microscope, and topographical changes of luminal urothelial structure were seen with a scanning electron microscope. • Biochemically malondialdehyde (MDA) and gluthatione (GSH) concentrations were analysed. In the PS group, there was degenerated urothelium with irregular uroplakin distribution, increased inflammatory cell infiltration, increased number of both granulated and activated mast cells, irregularity of GAG and penetration of RR into the intercellular spaces and dilated tight junctions. • In PS + ML group, there was relatively regular uroplakin distribution, a decrease in inflammatory cell infiltration, a decreased number of both activated and granulated mast cells in the mucosa, regular GAG and no penetration of RR into the intercellular areas, and regular tight junctions in most regions. • The significant decrease in MDA and the increased GSH concentrations in the PS + ML group was in accordance with the histological findings.

CONCLUSION

• Montelukast appears to have a protective function in the bladder injury model via the anti-inflammatory effects of this leukotriene receptor antagonist.

Idiopathic cystitis in domestic cats--beyond the lower urinary tract

Signs of lower urinary tract (LUT) disease in domestic cats can be acute or chronic, and can result from variable combinations of abnormalities within the lumen of the LUT, the parenchyma of the LUT itself, or other organ system(s) that then lead to LUT dysfunction. In the majority of cats with chronic signs of LUT dysfunction, no specific underlying cause can be confirmed after standard clinical evaluation of the LUT, so these cats typically are classified as having idiopathic cystitis. A syndrome in human beings commonly known as interstitial cystitis (IC) shares many features in common with these cats, permitting comparisons between the two species. A wide range of similarities in abnormalities has been identified between these syndromes outside as well as inside the LUT. A variety of potential familial and developmental risk factors also have been identified. These results have permitted generation of the hypothesis that some of these people have a disorder affecting the LUT rather than a disorder of the LUT. This perspective has suggested alternative diagnostic strategies and novel approaches to treatment, at least in cats. The purpose of this review is to summarize research investigations into the various abnormalities present in cats, to compare some of these findings with those identified in human beings, and to discuss how they might modify perceptions about the etiopathogenesis, diagnosis, and treatment of cats with this disease. Dedication: I dedicate this contribution to Professor Dennis J. Chew, whose collaboration, patience, and support made it all possible.

Mechanisms of action of sacral neuromodulation

The lower urinary tract dysfunction encompasses voiding, postvoiding, and storage symptoms. Conventional treatment modalities include pharmacotherapy and behavioural therapy. Sacral neuromodulation (SNM) is a safe and minimally invasive treatment modality that has recently gained wide acceptance in the management of urinary urge incontinence, urge frequency, and nonobstructive urinary retention, in particular, among those patients with conditions refractory to conventional methods. We searched multiple electronic databases through June 30, 2009 for eligible studies. We examined published clinical and experimental studies concerning the mechanisms of action of SNM. In the first part of the manuscript, we describe the anatomy and functions of the lower urinary tract including the reflexes involved in its functions and then review the pathophysiology of major types of the lower urinary tract dysfunction. In the second part, we discuss different ways for SNM to control various types of voiding dysfunction. The lower urinary tract dysfunctions affect millions of people worldwide and have a severe impact on their quality of life. SNM offers a safe and minimally invasive modality in the treatment of voiding dysfunctions, especially in patients with conditions refractory to conventional therapies.

Bladder pain syndrome

Bladder pain syndrome is a deceptively intricate symptom complex that is diagnosed on the basis of chronic pelvic pain, pressure, or discomfort perceived to be related to the urinary bladder, accompanied by at least one other urinary symptom. It is a diagnosis of exclusion in a patient who has experienced the symptoms for at least 6 weeks in the absence of any confusable diseases that may give rise to the symptoms. Symptoms compatible with the diagnosis are now thought to affect up to 3% of the female population in the United States with a 5:1 female-to-male preponderance. Diagnosis and treatment can be challenging, and misdiagnosis as a psychological problem, overactive bladder, or chronic urinary infection has plagued patients with the problem.

Pharmacologic attenuation of pelvic pain in a murine model of interstitial cystitis

BACKGROUND

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a bladder disease that causes debilitating pelvic pain of unknown origin, and IC/PBS symptoms correlate with elevated bladder lamina propria mast cell counts. Similar to IC/PBS patients, pseudorabies virus (PRV) infection in mice induces a neurogenic cystitis associated with bladder lamina propria mast cell accumulation and pelvic pain. We evaluated several drugs to determine the effectiveness of reducing PRV-induced pelvic pain.

METHODS

Neurogenic cystitis was induced by the injection of Bartha's strain of PRV into the abductor caudalis dorsalis tail base muscle of female C57BL/6 mice. Therapeutic modulation of pelvic pain was assessed daily for five days using von Frey filament stimulation to the pelvic region to quantify tactile allodynia.

RESULTS

Significant reduction of PRV-induced pelvic pain was observed for animals treated with antagonists of neurokinin receptor 1 (NK1R) and histamine receptors. In contrast, the H1R antagonist hydroxyzine, proton pump inhibitors, a histamine receptor 3 agonist, and gabapentin had little or no effect on PRV-induced pelvic pain.

CONCLUSION

These data demonstrate that bladder-associated pelvic pain is attenuated by antagonists of NK1R and H2R. Therefore, NK1R and H2R represent direct therapeutic targets for pain in IC/PBS and potentially other chronic pain conditions.

Interstitial cystitis: an unsolved enigma

Painful bladder syndrome/interstitial cystitis (PBS/IC) is a chronic disease of unknown etiology characterized by vague bladder pain and nonspecific urinary symptoms, such as urgency and frequency. Although it was initially considered to be a rare condition, its prevalence has significantly increased, possibly because of different definitions used and greater physician awareness. Because of the multiple diagnostic criteria used, there is significant variation in its prevalence. In addition, there is often a delay in the diagnosis of PBS/IC. It affects predominantly women of middle age, and it significantly decreases quality of life. Diagnosis of PBS/IC is mainly a diagnosis of exclusion; there are no characteristic symptoms or pathognomonic findings. Therefore, it is important to rule out diseases that have a similar clinical picture (i.e., urinary infections, bladder carcinoma) but definite therapies and worse prognosis if left untreated. PBS/IC management suffers from lack of evidence; many therapies are empiric or based on small studies and case series. Treatment includes supportive therapies (psychosocial, behavioral, physical), oral treatments, and intravesical treatments, whereas other more invasive treatments such as electric neuromodulation and reconstructive surgery are reserved for refractory cases. Physicians should always keep in mind the diagnosis of PBS/IC in patients presenting with chronic urinary symptoms after excluding other more common diseases.

Use of pentosan polysulphate in cats with idiopathic, non-obstructive lower urinary tract disease: A double-blind, randomised, placebo-controlled trial

Idiopathic feline lower urinary tract disease (FLUTD) is a common clinical entity where different treatments, for example glycosaminoglycans (GAGs) such as pentosan polysulphate (PPS), are advocated. However, few treatments have been investigated by well-controlled clinical trials. This paper compares the use of PPS in FLUTD compared to placebo. Of the 18 cats in the experiment, nine were treated with PPS and nine were treated with placebo with subcutaneous injections of 3 mg/kg PPS or placebo day 1, 2, 5 and 10. The study was double-blind, randomised and placebo-controlled. Revaluation was performed after 5 and 10 days, 2 weeks, 2, 6 and 12 months. There were no statistically significant differences concerning clinical signs between groups during treatment or at re-evaluation, except for pretreatment stressful events where PPS-treated cats had experienced significantly more stressful events compared to cats treated with placebo before entering the study. Six cats (33%) showed recurrence of clinical signs during the entire study period, and only one of these cats had more than one recurrent episode. One cat (placebo) was euthanased 7 days after initial treatment because of recurrence of clinical signs. Another cat (placebo) was euthanased due to other reasons after 6 months. At 2 weeks two cats (placebo and PPS) showed clinical signs. At 2 months re-evaluation one cat showed mild clinical signs. At 6 and 12 months all remaining 16 cats were healthy. Idiopathic, non-obstructive FLUTD is a self-limiting disease with good short-term and excellent long-term prognosis without treatment. Whether or not PPS may be beneficial in a subpopulation of cats with continuous or frequently recurring clinical signs may be elucidated in forthcoming double-blind, randomised and placebo-controlled trials including only this subpopulation of cats.

Herpes simplex virus vector-mediated gene delivery for the treatment of lower urinary tract pain

Interstitial cystitis (IC)/painful bladder syndrome (PBS) is a painful debilitating chronic visceral pain disorder of unknown etiology that affects an estimated 1 million people in the United States alone. It is characterized by inflammation of the bladder that results in chronic pelvic pain associated with bladder symptoms of urinary frequency and urgency. Regardless of the etiology, IC/PBS involves either increased and/or abnormal activity in afferent nociceptive sensory neurons. Pain-related symptoms in patients with IC/PBS are often very difficult to treat. Both medical and surgical therapies have had limited clinical utility in this debilitating disease and numerous drug treatments, such as heparin, dimethylsulfoxide and amitriptyline, have proven to be palliative at best, and in some IC/PBS patients provide no relief whatsoever. Although opiate narcotics have been employed to help alleviate IC/PBS pain, this strategy is fraught with problems as systemic narcotic administration causes multiple unwanted side effects including mental status change and constipation. Moreover, chronic systemic narcotic use leads to dependency and need for dose escalation due to tolerance; therefore, new therapies are desperately needed to treat refractory IC/PBS. This has led our group to develop a gene therapy strategy that could potentially alleviate chronic pelvic pain using the herpes simplex virus-directed delivery of analgesic proteins to the bladder.

Combination of MS protein identification and bioassay of chromatographic fractions to identify biologically active substances from complex protein sources

Purification of biologically active proteins from complex biological sources is a difficult task, usually requiring large amounts of sample and many separation steps. We found an active substance in a serum response element-dependent luciferase reporter gene bioassay in interstitial cystitis urine that we attempted to purify with column chromatography and the bioassay. With anion-exchange Mono Q and C4 reversed-phase columns, apparently sharp active peaks were obtained. However, more than 20 kinds of proteins were identified from the active fractions with MS, indicating that the purification was not complete. As further purification was difficult, we chose a candidate molecule by means of studying the correlation between MS protein identification scores and bioassay responses of chromatographic fractions near the active peaks. As a result, epidermal growth factor (EGF) was nominated as a candidate molecule among the identified proteins because the elution profile of EGF was consistent with that of the bioassay, and the correlation coefficient of EGF between MS protein identification scores and bioassay responses was the highest among all the identified proteins. With recombinant EGF and anti-EGF and anti-EGF receptor antibodies, EGF was confirmed to be the desired substance in interstitial cystitis urine. This approach required only 20 ml of urine sample and two column chromatographic steps. The combination of MS protein identification and bioassay of chromatographic fractions may be useful for identifying biologically active substances from complex protein sources.

Increased concentration of neutrophil elastase in urine from patients with interstitial cystitis

OBJECTIVE

To identify proteins associated with interstitial cystitis (IC), protein profiles were analyzed using a proteomics-based approach. The study tested whether neutrophil elastase in urine correlates with the symptomatic condition of IC.

MATERIAL AND METHODS

Proteins in urine from IC patients and healthy subjects were analyzed through a comparative proteomics approach using two-dimensional difference in-gel electrophoresis and nano-liquid chromatography-tandem mass spectrometry. Neutrophil elastase activity was measured by the digestion of peptide substrate.

RESULTS

The urinary neutrophil elastase concentration was significantly higher in IC patients with pain than in healthy subjects. It was significantly increased in patients with small bladder capacity (median 6.31 ng/ml in IC with a bladder capacity < 200 ml vs 1.15 ng/ml in IC with a bladder capacity > or = 200 ml and 0.18 ng/ml in healthy bladders, p < 0.01). The concentration of neutrophil elastase did not correlate with the neutrophil count in the urine of IC patients.

CONCLUSION

The concentration of neutrophil elastase increased in the urine of the IC patient subset with bladder pain and small bladder capacity.

The controversial role of mast cells in tumor growth

Mast cells (MCs) were first described by Paul Ehrlich (Beiträge zur Theorie und Praxis der Histologischen Färbung, Thesis, Leipzig University, 1878). They have long been implicated in the pathogenesis of allergic reactions and protective responses to parasites. However, their functional role has been found to be complex and multifarious. MCs are also involved in various cell-mediated immune reactions and found in tissues from multiple disease sites, and as a component of the host reaction to bacteria, parasite, and even virus infections. They also participate in angiogenic and tissue repair processes after injury. The importance of a possible functional link between chronic inflammation and cancer has long been recognized. As most tumors contain inflammatory cell infiltrates, which often include plentiful MCs, a possible contribution of these cells to tumor development has emerged. In this review, general biology of mast cells, their development, anatomical distribution, and phenotype as well as their secretory products will first be discussed. The specific involvement of MCs in tumor biology and tumor fate will then be considered, with particular emphasis on their capacity to stimulate tumor growth by promoting angiogenesis and lymphangiogenesis. Finally, it is suggested that mast cells may serve as a novel therapeutic target for cancer treatment.