The enigma of men with interstitial cystitis/bladder pain syndrome

Changes in nerve growth factor signaling in female mice with cyclophosphamide-induced cystitis

IC/BPS is a chronic inflammatory pelvic pain syndrome characterized by lower urinary tract symptoms including unpleasant sensation (pain, pressure, or discomfort) in the suprapubic or bladder area, as well as increased urinary frequency and urgency, and decreased bladder capacity. While its etiology remains unknown, increasing evidence suggests a role for changes in nerve growth factor (NGF) signaling. However, NGF signaling is complex and highly context dependent. NGF activates two receptors, TrkA and p75NTR, which activate distinct but overlapping signaling cascades. Dependent on their coexpression, p75NTR facilitates TrkA actions. Here, we show effects of CYP treatment and pharmacological inhibition of p75NTR (via LM11A-31) and TrkA (ARRY-954) on NGF signaling-related proteins: NGF, TrkA, phosphorylated (p)-TrkA, p75NTR, p-ERK1/2, and p-JNK. Cystitis conditions were associated with increased urothelial NGF expression and decreased TrkA and p75NTR expression as well as altering their co-expression ratio; phosphorylation of ERK1/2 and JNK were also altered. Both TrkA and p75NTR inhibition affected the activation of signaling pathways downstream of TrkA, supporting the hypothesis that NGF actions during cystitis are primarily TrkA-mediated. Our findings, in tandem with our recent companion paper demonstrating the effects of TrkA, TrkB, and p75NTR inhibition on bladder function in a mouse model of cystitis, highlight a variety of potent therapeutic targets and provide further insight into the involvement of NGF signaling in sustained conditions of bladder inflammation.

Effects of pharmacological neurotrophin receptor inhibition on bladder function in female mice with cyclophosphamide-induced cystitis

Interstitial cystitis/bladder pain syndrome is a chronic inflammatory pelvic pain syndrome of unknown etiology characterized by a number of lower urinary tract symptoms, including increased urinary urgency and frequency, bladder discomfort, decreased bladder capacity, and pelvic pain. While its etiology remains unknown, a large body of evidence suggests a role for changes in neurotrophin signaling, particularly that of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). Here, we evaluated the effects of pharmacological inhibition of the NGF receptor TrkA, BDNF receptor TrkB, and pan-neurotrophin receptor p75NTR on bladder function in acute (4-hour) and chronic (8-day) mouse models of cyclophosphamide (CYP)-induced cystitis. TrkA inhibition via ARRY-954 significantly increased intermicturition interval and bladder capacity in control and acute and chronic CYP-treatment conditions. TrkB inhibition via ANA-12 significantly increased intermicturition interval and bladder capacity in acute, but not chronic, CYP-treatment conditions. Interestingly, intermicturition interval and bladder capacity significantly increased following p75NTR inhibition via LM11A-31 in the acute CYP-treatment condition, but decreased in the chronic condition, potentially due to compensatory changes in neurotrophin signaling or increased urothelial barrier dysfunction in the chronic condition. Our findings demonstrate that these receptors represent additional potent therapeutic targets in mice with cystitis and may be useful in the treatment of interstitial cystitis and other inflammatory disorders of the bladder.

Management of Bladder Pain Syndrome (BPS): A Practical Guide

Bladder pain syndrome (BPS) is a prevalent and pervasive disease. The physical and psychological sequelae can be very burdensome for the patient, and the condition represents a real challenge for the clinician as well. With no simple pathognomonic test, finding harmony in navigating patient care can be demanding. Diagnosis and management rely upon a multidisciplinary and holistic approach. Treatment options include conservative measures and pharmacotherapies as well as bladder instillation therapies. Ultimately, surgery may be offered but only in cases of refractory disease. This article offers a pragmatic guide for clinicians managing this challenging disease.

Neuroinflammatory gene expression analysis reveals potential novel mediators and treatment targets in interstitial cystitis with Hunner lesions

Background

We sought to study differential neuroinflammatory gene expression in men with interstitial cystitis (IC) with Hunner lesions compared with asymptomatic controls using NanoString, which uses barcoded probes to measure hundreds of genes. IC is a heterogenous condition lacking reliable biomarkers, and a subset of patients exhibits Hunner lesions, implicating the bladder as an inflammatory pain generator.

Methods

Blood, urine, and bladder biopsies were collected from 6 men with IC and Hunner lesions. 7 asymptomatic controls had blood and urine collected and 2 benign bladder biopsies were obtained from our tissue bank. RNA was isolated and analyzed with NanoString Human Neuroinflammation panel. Gene expression was considered significant if there was a >1.5-fold change and adjusted P value <0.05 compared with controls.

Results

Mean patient age was 61.5 years with 8 years median symptom duration. In bladder tissue, while many cytokine and chemokine genes had higher expression as expected (e.g., TNF, CXCL10), other significant genes included TRPA1 (1098-fold increased, expressed in pain sensing neurons) and TNFRSF17 (735-fold, B-cell related). In urine, there was 114-fold increase in S1PR4, which mediates pain via TRP-dependent pathways. A patient on cyclosporine had lower inflammatory gene expression levels relative to other IC patients, but no difference in TRPA1.

Conclusions

Men with IC and Hunner lesions have a diverse set of neuroinflammatory genes with differential expression compared to controls. We identified genes linked to neuropathic pain through the TRP pathway and this expression was not reduced by cyclosporine. These findings open a new direction for biomarker and therapeutic discovery.

Cross-organ sensitization between the prostate and bladder in an experimental rat model of lipopolysaccharide (LPS)-induced chronic pelvic pain syndrome

BACKGROUND

The aim of the current study was to investigate the effects of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) on bladder function via prostate-to-bladder cross-sensitization in a rat model of lipopolysaccharide (LPS)-induced prostate inflammation.

METHODS

Male rats were intraprostatically injected with LPS or saline, serving as control. Micturition parameters were examined in a metabolic cage 10 or 14 days later. Subsequently, to evaluate bladder function, cystometry was performed. Micturition cycles were induced by saline infusion and cholinergic and purinergic contractile responses were measured by intravenous injection with methacholine and ATP, respectively. Thereafter, the prostate and bladder were excised and assessed histopathologically for possible inflammatory changes.

RESULTS

Metabolic cage experiments showed increased urinary frequency in rats with LPS-induced CP/CPPS. Cystometry showed a significant increase in the number of non-voiding contractions, longer voiding time and lower compliance in CP/CPPS animals compared to controls. Induction of CP/CPPS led to significantly reduced cholinergic and purinergic bladder contractile responses. Histopathological analysis demonstrated prostatic inflammation in CP/CPPS animals. There were no significant differences between the groups regarding the extent or the grade of bladder inflammation. Prostate weight was not significantly different between the groups.

CONCLUSIONS

The present study shows that prostate-to-bladder cross-sensitization can be triggered by an infectious focus in the prostate, giving rise to bladder overactivity and alterations in both afferent and efferent signalling. Future studies are required to fully understand the underlying mechanisms.

Using the UPOINT system to manage men with chronic pelvic pain syndrome

OBJECTIVE

: To outline our approach for the evaluation and management of patients with chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) based on our interpretation and application of currently available evidence.

METHODS

: CP/CPPS in men is a medical condition that plagues both the patient and the practitioner, as it is widely believed to be poorly understood and difficult to treat. While pelvic pain is typically the predominant symptom, many men may exhibit voiding symptoms, sexual dysfunction and psychiatric complaints. Still, most studies of CP/CPPS management have evaluated singular treatments, without focussing on individual patients' clinical phenotypes. This is a clinically practical mini-review based on the authors' interpretation and application of currently available evidence related to management of CP/CPPS.

RESULTS

: Patient evaluation should consist of history and physical examination (with focus on the genitourinary and digital rectal examination), laboratory tests (including urine analysis and urine culture with consideration of pre- and post-prostate massage urine cultures), post-void residual, and questionnaires including the National Institutes of Health Chronic Prostatitis Symptoms Index, which helps assess symptom severity and treatment response. Once CP/CPPS is diagnosed, the UPOINT phenotype system, which classifies patients into six domains: Urinary, Psychosocial, Organ Specific, Infectious, Neurological/systemic and Tenderness of skeletal muscles, is used to guide treatment. Each domain is characterised by specific complaints and thus is responsive to distinct treatments. As patients may be grouped into multiple domains, each patient's overall multimodal treatment can vary.

CONCLUSION

: Using the UPOINT phenotype system is a holistic approach that can yield significant benefits for patients with CP/CPPS.

MicroRNA-495 alleviates ulcerative interstitial cystitis via inactivating the JAK-STAT signaling pathway by inhibiting JAK3

INTRODUCTION AND HYPOTHESIS

As a notable chronic disorder, the incidence of interstitial cystitis (IC) has been documented to have increased among the female population with activity in microRNA-495 (miR-495) implicated in this disease. The current study was aimed at elucidating the effects associated with miR-495 on the inflammatory response and bladder fibrosis in rats with ulcerative IC via the JAK-STAT pathway by targeting JAK3.

METHODS

Ulcerative IC rat models were established. The targeting relationship between JAK3 and miR-495 was evaluated using luciferase reporter assay. After gain- or loss-of-function assays, mast-cell infiltration was assessed using toluidine blue staining, bladder fibrosis using Masson staining, and NO content using nitrate reductase method. JAK3 protein expression was detected by immunohistochemistry, JAK3, STAT1, STAT3, TGFβ-1, Col-I, Col-III, JAK1, JAK2, p-STAT1, and p-STAT3 expression by RT-qPCR and Western blot analysis, and serum IL-6, IL-8, IL-10, IL-17, and TNF-α levels in rats by ELISA.

RESULTS

Following transfection of overexpressed miR-495 or siRNA-JAK3, a diminished degree of mast-cell infiltration, number of mast cells, bladder fibrosis, NO content, JAK3-positive expression, mRNA expression of JAK3, STAT1, STAT3, TGFβ-1, Col-I, Col-III, protein expression of JAK1, JAK2, JAK3, p-STAT1, p-STAT3, and expression of IL-6, IL-8, IL-10, IL-17, and TNF-α were identified.

CONCLUSIONS

Collectively, our key findings provide evidence supporting the notion that the overexpression of miR-495 ameliorates inflammatory response and bladder fibrosis in ulcerative IC rat models via inactivation of the JAK-STAT signaling pathway by inhibiting JAK3.