Pain in interstitial cystitis/bladder pain syndrome: do characteristics differ in ulcerative and non-ulcerative subtypes?

MIF-Modulated Spinal Proteins Associated with Persistent Bladder Pain: A Proteomics Study

Bladder pain is a prominent symptom in Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS). We studied spinal mechanisms of bladder pain in mice using a model where repeated activation of intravesical Protease Activated Receptor-4 (PAR4) results in persistent bladder hyperalgesia (BHA) with little or no bladder inflammation. Persistent BHA is mediated by spinal macrophage migration inhibitory factor (MIF), and is associated with changes in lumbosacral proteomics. We investigated the contribution of individual spinal MIF receptors to persistent bladder pain as well as the spinal proteomics changes associated with relief of persistent BHA by spinal MIF antagonism. Female mice with persistent BHA received either intrathecal (i.t.) MIF monoclonal antibodies (mAb) or mouse IgG1 (isotype control antibody). MIF antagonism temporarily reversed persistent BHA (peak effect: 2 h), while control IgG1 had no effect. Moreover, i.t. antagonism of the MIF receptors CD74 and C-X-C chemokine receptor type 4 (CXCR4) partially reversed persistent BHA. For proteomics experiments, four separate groups of mice received either repeated intravesical scrambled peptide and sham i.t. injection (control, no pain group) or repeated intravesical PAR4 and: sham i.t.; isotype IgG1 i.t. (15 μg); or MIF mAb (15 μg). L6-S1 spinal segments were excised 2 h post-injection and examined for proteomics changes using LC-MS/MS. Unbiased proteomics analysis identified and relatively quantified 6739 proteins. We selected proteins that showed significant changes compared to control (no pain group) after intravesical PAR4 (sham or IgG i.t. treatment) and showed no significant change after i.t. MIF antagonism. Six proteins decreased during persistent BHA (V-set transmembrane domain-containing protein 2-like confirmed by immunohistochemistry), while two proteins increased. Spinal MIF antagonism reversed protein changes. Therefore, spinal MIF and MIF receptors mediate persistent BHA and changes in specific spinal proteins. These novel MIF-modulated spinal proteins represent possible new targets to disrupt spinal mechanisms that mediate persistent bladder pain.

Urothelial Oxidative Stress and ERK Activation Mediate HMGB1-Induced Bladder Pain

Activation of intravesical protease activated receptors-4 (PAR4) results in bladder pain through the release of urothelial macrophage migration inhibitory factor (MIF) and high mobility group box-1 (HMGB1). We aimed to identify HMGB1 downstream signaling events at the bladder that mediate HMGB1-induced bladder pain in MIF-deficient mice to exclude any MIF-related effects. We studied whether oxidative stress and ERK activation are involved by examining bladder tissue in mice treated with intravesical disulfide HMGB1 for 1 h and analyzed with Western blot and immunohistochemistry. HMGB1 intravesical treatment increased urothelium 4HNE and phospho-ERK1/2 staining, suggesting that HMGB1 increased urothelial oxidative stress and ERK activation. Furthermore, we examined the functional roles of these events. We evaluated lower abdominal mechanical thresholds (an index of bladder pain) before and 24 h after intravesical PAR4 or disulfide HMGB1. Intravesical pre-treatments (10 min prior) included: N-acetylcysteine amide (NACA, reactive oxygen species scavenger) and FR180204 (FR, selective ERK1/2 inhibitor). Awake micturition parameters (voided volume; frequency) were assessed at 24 h after treatment. Bladders were collected for histology at the end of the experiment. Pre-treatment with NACA or FR significantly prevented HMGB1-induced bladder pain. No significant effects were noted on micturition volume, frequency, inflammation, or edema. Thus, HMGB1 activates downstream urothelial oxidative stress production and ERK1/2 activation to mediate bladder pain. Further dissection of HMGB1 downstream signaling pathway may lead to novel potential therapeutic strategies to treat bladder pain.

Exploration of the core genes in ulcerative interstitial cystitis/bladder pain syndrome

Objective:

Interstitial cystitis (IC)/bladder pain syndrome (BPS) is a chronic inflammatory disease that can cause bladder pain and accompanying symptoms, such as long-term urinary frequency and urgency. IC/BPS can be ulcerative or non-ulcerative. The aim of this study was to explore the core genes involved in the pathogenesis of ulcerative IC, and thus the potential biomarkers for clinical treatment.

Materials and Methods:

First, the gene expression dataset GSE11783 was downloaded using the Gene Expression Omnibus (GEO) database and analyzed using the limma package in R to identify differentially expressed genes (DEGs). Then, the Database for Annotation, Visualization and Integrated Discovery (DAVID) was used for Gene Ontology (GO) functional analysis, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) was used for pathway enrichment analysis. Finally, the protein-protein interaction (PPI) network was constructed, and key modules and hub genes were determined using the STRING and Cytoscape software. The resulting key modules were then analyzed for tissue-specific gene expression using BioGPS.

Results:

A total of 216 up-regulated DEGs and 267 down-regulated genes were identified, and three key modules and nine hub genes were obtained.

Conclusion:

The core genes (CXCL8, CXCL1, IL6) obtained in this study may be potential biomarkers of interstitial cystitis with guiding significance for clinical treatment.

Phenotypes of BPS/IC

Purpose of Review

The aim of this review is to summarise the latest research related to different phenotypes of BPS/IC, addressing the evidence for current well-defined phenotypes as well as identifying novel potential phenotypes and highlighting areas for future study.

Recent Findings

Two distinct phenotypes of BPS/IC are well-recognised: Hunner’s lesion disease and non-Hunner’s lesion BPS/IC. Recent studies have shown these phenotypes exhibit distinct clinical, pathological and cystoscopic features, and targeted treatment to Hunner’s lesions can prove effective. Recent studies have also identified new potential phenotypes based on biochemical, molecular and histological markers, pathophysiological mechanisms of disease, clinical features, cystoscopic findings, radiological features and urodynamic factors. This evidence has improved our understanding of the underlying mechanism of disease and may enable more personalised and targeted therapy in the future.

Summary

Novel phenotypes of BPS/IC relate to the presence of certain biomarkers, alterations in the urinary microbiome, the characteristics of pain and presence of co-existing somatic and psychosocial conditions, altered patterns of brain white matter changes and urodynamic features. Further study is required to evaluate whether these potential phenotypes are clinically useful based on their ability to guide treatment selection and predict outcome from therapy, and therefore optimise therapeutic outcomes.

Hunner lesion disease differs in diagnosis, treatment and outcome from bladder pain syndrome: an ESSIC working group report

Objectives: There is confusion about the terms of bladder pain syndrome (BPS) and Interstitial Cystitis (IC). The European Society for the Study of IC (ESSIC) classified these according to objective findings [9]. One phenotype, Hunner lesion disease (HLD or ESSIC 3C) differs markedly from other presentations. Therefore, the question was raised as to whether this is a separate condition or BPS subtype.Methods: An evaluation was made to explore if HLD differs from other BPS presentations regarding symptomatology, physical examination findings, laboratory tests, endoscopy, histopathology, natural history, epidemiology, prognosis and treatment outcomes.Results: Cystoscopy is the method of choice to identify Hunner lesions, histopathology the method to confirm it. You cannot distinguish between main forms of BPS by means of symptoms, physical examination or laboratory tests. Epidemiologic data are incomplete. HLD seems relatively uncommon, although more frequent in older patients than non-HLD. No indication has been presented of BPS and HLD as a continuum of conditions, one developing into the other.Conclusions: A paradigm shift in the understanding of BPS/IC is urgent. A highly topical issue is to separate HLD and BPS: treatment results and prognoses differ substantially. Since historically, IC was tantamount to Hunner lesions and interstitial inflammation in the bladder wall, still, a valid definition, the term IC should preferably be reserved for HLD patients. BPS is a symptom syndrome without specific objective findings and should be used for other patients fulfilling the ESSIC definitions.

Advanced Management of Patients With Ulcerative Interstitial Cystitis/Bladder Pain Syndrome

OBJECTIVE

To describe a stepwise management of patients with interstitial cystitis/bladder pain syndrome (IC/BPS) with Hunner's lesions and present single institution long-term outcomes.

METHODS

This is a retrospective review of a single tertiary center experience with management of patients with Hunner's lesions from January 2005 to January of 2015. Patients who met the diagnostic criteria for IC/BPS were included. Systematic approach to treatment of patients with Hunner's lesions is proposed based on our results.

RESULTS

Fifty-five patients with IC/BPS and Hunner's lesions were included. Mean age was 65.0 ±12.7 years, 76.4% (42/55) were female, and median symptom duration was 2 years (interquartile range [IQR] 1.7). All patients had a biopsy to rule out malignancy with therapeutic fulguration which resulted in subjective symptom improvement in 81.8% (45/55) and median time to repeat procedures was 12 months (IQR 621). Triamcinolone injection into the lesion was done in 35 patients and 91.4% (32/35) reported subjective improvement. Repeat injections were done for 74% (26/35) and median time between injections was 8 months (IQR 4, 13). AUA symptom scores and quality of life improved significantly with both treatment modalities. Adjunctive treatment with cyclosporine was used in 47.2% (26/55), and 7.2% (4/55) went on to have a cystectomy.

CONCLUSION

Patients with Hunner's lesions benefit from early progression from conservative treatments to endoscopic management. Excellent symptom control can be achieved with biopsy/fulguration and triamcinolone injections but recurrence is common and repeat treatments are needed for most patients.

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.

Differences in Urodynamic Parameters According to the Presence of a Hunner Lesion in Women With Interstitial Cystitis/Bladder Pain Syndrome

Purpose

Differences in the severity of subjective symptoms have been noted depending on whether a Hunner lesion is present in women with interstitial cystitis/bladder pain syndrome (IC/BPS). In this study, we aimed to identify differences in objective urodynamic parameters in women with IC/BPS according to the presence of a Hunner lesion.

Methods

This cross-sectional study included a total of 55 patients with IC/BPS. IC/BPS and the presence of a Hunner lesion on cystoscopy were diagnosed according to American Urological Association guidelines. The patients were categorized into a Hunner IC/BPS group and a non-Hunner IC/BPS group according to the presence of a Hunner lesion on cystoscopy. At the initial visit, a medical history was taken from all patients with IC/BPS, and they underwent symptom assessment using a 3-day voiding diary and laboratory tests. A urodynamic study was then performed before any treatment was performed. Baseline characteristics and urodynamic parameters were compared between the 2 groups.

Results

Of the 55 patients, 23 (41.8%) had a Hunner lesion on cystoscopy. As documented in the voiding diaries, the Hunner IC/BPS group had more frequent voids and a smaller maximal voided volume (P=0.045, P<0.001, respectively). Regarding urodynamic parameters, the mean volume at the first desire to void, normal desire to void, strong desire to void (SDV), and maximum cystometric bladder capacity (MBC) was significantly lower in the Hunner IC/BPS group (P=0.001, P=0.004, P<0.001, and P<0.001, respectively). On receiver operating characteristic curve analysis, patients with an SDV≤210 mL (area under the curve [AUC]=0.838, P<0.001) and an MBC≤234 mL (AUC=0.857, P<0.001) were likely to be in the Hunner IC/BPS group.

Conclusions

The differences in patients’ subjective symptoms between the Hunner IC/BPS and non-Hunner IC/BPS groups were confirmed to correspond to differences in objective urodynamic parameters.

Urothelial Functional Protein and Sensory Receptors in Patients With Interstitial Cystitis/Bladder Pain Syndrome With and Without Hunner's Lesion

OBJECTIVE

To investigate the urothelium function and sensory receptors difference between interstitial cystitis/bladder pain syndrome (IC/BPS) patients with or without Hunner's lesion.

METHODS

Fourteen female IC/BPS patients with Hunner's lesion (Hunner IC) and 14 age-matched IC/BPS patients without Hunner's lesions (non-Hunner IC) were enrolled. Bladder mucosa biopsies were obtained. Bladder inflammation, eosinophil infiltration, and urothelial denudation were graded on a 4-point scale after staining with hematoxylin and eosin. Adhesive protein E-cadherin, tryptase, and zonula occuldens-1 in the bladder tissues were assessed with immunofluorescence staining. Urothelial muscarinic receptors M2, M3, endothelial nitric oxide synthase (eNOS), and purinergic receptor P2X3 were evaluated by Western blotting.

RESULTS

Hunner IC patients had a significantly higher mean visual analog scale pain score and smaller cystometric bladder capacity than non-Hunner IC patients. The Hunner IC bladder specimens showed more severe or moderate eosinophilic infiltration and urothelial denudation than the non-Hunner IC bladder specimens did. The E-cadherin expression was significantly lower, and eNOS expression was significantly higher in the Hunner IC bladder samples than in the non-Hunner IC samples. The other functional proteins or sensory receptors did not differ between groups.

CONCLUSION

Bladder inflammation and urothelial cell adhesion defects were more severe in the Hunner IC than that in the non-Hunner IC patients. eNOS was significantly higher in the Hunner IC than in the non-Hunner IC bladder samples, suggesting that eNOS expression difference may implicate different pathogenesis in 2 types of IC.

Role of cystoscopy and hydrodistention in the diagnosis of interstitial cystitis/bladder pain syndrome

There are controversies about whether cystoscopy with or without hydrodistention (HD) plays a role in the diagnosis and treatment of interstitial cystitis/bladder pain syndrome (IC/BPS). We reviewed the recommendations of various societies and associations of greater impact in this complex disease, analyzing the indications, technique, findings and complications of this procedure.

A novel method for assessing bladder-related pain reveals the involvement of nerve growth factor in pain associated with cyclophosphamide-induced chronic cystitis in mice

BACKGROUND

Pain is a prominent feature of interstitial cystitis/painful bladder syndrome (IC/PBS), but the underlying mechanisms are not fully understood. There is a lack of well-characterized research tools, such as pain evaluation methods and experimental animal models, for investigating non-ulcerative cystitis. We developed a novel method for evaluating bladder pain in mice with cyclophosphamide (CYP)-induced cystitis.

METHODS

Cystitis was produced by a single intraperitoneal injection of CYP (300 mg/kg) or repeated injections of CYP (150 mg/kg once daily for 4 days). Blunt stimulation with a cotton probe was applied to the abdominal region, and the thresholds for withdrawal responses were measured quantitatively using an anaesthesiometer.

RESULTS

The single injection of CYP provoked acute cystitis with severe bladder inflammation in mice. In these mice, we could detect an increased sensitivity to blunt stimulation, which was abolished by intravesical lidocaine. The stimulation induced phosphorylation of extracellular signal-regulated kinases in bladder-projecting sensory neurons. Chronic treatment with CYP produced persistent pain responses to the blunt stimulus. Although there were few signs of bladder inflammation in these mice, the concentration of nerve growth factor (NGF) was elevated in bladder tissue, and NGF antiserum inhibited the hypersensitivity.

CONCLUSIONS

The blunt probe method is useful for evaluating bladder pain signalling in mice, and revealed the involvement of an NGF-sensitive pain pathway in chronic cystitis pain. This assessment method may be useful for studying the pathophysiology of bladder pain and for developing therapeutic strategies for non-ulcerative IC/PBS in patients.

Ulcerative and nonulcerative forms of bladder pain syndrome/interstitial cystitis do not differ in symptom intensity or response to onabotulinum toxin A

OBJECTIVE

To determine whether intratrigonal Onabotulinum toxin A (OnabotA) injection produces a different symptomatic outcome and duration of effect on ulcerative (Ulc) and nonulcerative (NUlc) bladder pain syndrome/interstitial cystitis (BPS/IC) patients and to compare the urinary levels of neurotrophines (NGF, BDNF, and GDNF) in response to OnabotA.

METHODS

Ten Ulc and 14 NUlc bladder pain syndrome/interstitial cystitis patients were included in this study. OnabotA (100 U) was injected in 10 trigonal sites, each receiving 10 U in 1 mL of saline. Outcome measures included pain visual analog scale (0-10), a 3-day voiding chart, O'Leary-Sant Score (OSS), and quality of life (QoL) from International Prostate Symptoms Score assessed before treatment, 1 month after injection, and every 3 months afterwards. Urinary NGF, BDNF, and GDNF were accessed using ELISA, at same time points. Treatment duration was determined at the time patients requested another injection.

RESULTS

Patients had a mean age of 40 ± 12 years in the Ulc and 47 ± 13 years in the NUlc group (ns). Mean values at baseline of pain intensity, frequency, nocturia, OSS, QoL, and urinary NGF, BDNF, GDNF were identical in the 2 groups. Patients with the Ulc phenotype had a longer duration of symptoms (28.8 ± 11 vs 19.2 ± 8 months, P = .018). Both groups responded equally to OnabotA, with significant improvements in pain intensity, frequency, nocturia, OSS, QoL, and urinary NGF, BDNF, GDNF. The effect lasted for 9 ± 2.8 (Ulc) and 10.5 ± 2 (NUlc) months.

CONCLUSION

In this cohort, Ulc and NUlc patients had similar symptoms at baseline and comparable clinical response to intratrigonal OnabotA. These findings suggest that pain may not be directly related with ulcers themselves.

Intravesical liposome and antisense treatment for detrusor overactivity and interstitial cystitis/painful bladder syndrome

Purpose. The following review focuses on the recent advancements in intravesical drug delivery, which brings added benefit to the therapy of detrusor overactivity and interstitial cystitis/painful bladder syndrome (IC/PBS). Results. Intravesical route is a preferred route of administration for restricting the action of extremely potent drugs like DMSO for patients of interstitial cystitis/painful bladder syndrome (IC/PBS) and botulinum toxin for detrusor overactivity. Patients who are either refractory to oral treatment or need to mitigate the adverse effects encountered with conventional routes of administration also chose this route. Its usefulness in some cases can be limited by vehicle (carrier) toxicity or short duration of action. Efforts have been underway to overcome these limitations by developing liposome platform for intravesical delivery of biotechnological products including antisense oligonucleotides. Conclusions. Adoption of forward-thinking approaches can achieve advancements in drug delivery systems targeted to future improvement in pharmacotherapy of bladder diseases. Latest developments in the field of nanotechnology can bring this mode of therapy from second line of treatment for refractory cases to the forefront of disease management.