Interstitial cystitis/bladder pain syndrome: The evolving landscape, animal models and future perspectives

Divergent histopathological and molecular patterns in chemically induced interstitial cystitis/bladder pain syndrome rat models

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a complex chronic pain disorder with an elusive etiology and nonspecific symptoms. Although numerous animal models with phenotypes similar to human disease have been established, no available regimen can consistently alleviate clinical symptoms. This dilemma led us to question whether current animal models adequately represent IC/BPS. We compared four commonly used IC/BPS rat models to determine their diverse histopathological and molecular patterns. Female rats were given single treatments with hydrochloric acid (HCL), acetic acid (AA), protamine sulfate plus lipopolysaccharide (PS + LPS), or cyclophosphamide (CYP) to induce IC/BPS. Bladder sections were stained for histopathologic evaluation, and mRNA expression profiles were examined using next-generation sequencing and gene set analyses. Mast cell counts were significantly higher in the HCL and AA groups than in the PS + LPS, CYP, and control groups, but only the AA group showed significant collagen accumulation. The models differed substantially in terms of their gene ontology and Kyoto encyclopedia of genes and genomes pathways. Our observations suggest that none of these rat models fully reflects the complexity of IC/BPS. We recommend that future studies apply and compare multiple models simultaneously to fully replicate the complicated features of IC/BPS.

Stem cell therapy for interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic disease with limited treatment options. Current multidisciplinary approach targeting bladder inflammation and urothelial dysfunction has limited durable effect that major surgery is ultimately required for both Hunner and non-Hunner type IC. Various investigational attempts are underway to avoid such operations and preserve the urinary bladder. Stem cell therapy is a fascinating option for treating chronic illnesses. Stem cells can self-renew, restore damaged tissue, and have paracrine effects. The therapeutic efficacy and safety of stem cell therapy have been demonstrated in numerous preclinical models, primarily chemically induced cystitis rat models. Only one clinical trial (phase 1 study) has investigated the safety of human embryonic stem cell-derived mesenchymal stem cells in three Hunner-type IC patients. Under general anesthesia, participants underwent cystoscopic submucosal stem cell injection (2.0 × 107 stem cells/5 mL). No safety issues were reported up to 12 months of follow-up and long-term follow-up (up to 3 years). Although there were variations in therapeutic response, all patients reported significant improvement in pain at 1 month postoperatively. One patient underwent fulguration of the Hunner lesion after the trial, but others reported an overall improvement in pain. The analysis on phase 1/2a trial which had several modifications in protocol is currently ongoing. Despite several limitations that need to be overcome, stem cell therapy could be a potential therapeutic option for treating IC/BPS. Clinical outcome on phase 1/2a trial is important and might provide more insight into the clinical application of stem cell therapy for IC/BPS.

Modified Botulinum Toxin Type A Injections Improve Symptoms Associated With Interstitial Cystitis/Bladder Pain Syndrome in Women: A Retrospective Cohort Study

OBJECTIVE

To investigate the efficacy and safety of modified botulinum toxin type A (BoNT-A) injections (with additional periurethral injection [PUI] of BoNT-A) for the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS).

METHODS

This single-center, retrospective cohort study included 52 adult female patients with IC/BPS, with 24 patients receiving conventional BoNT-A injections and 28 receiving modified BoNT-A injections. The primary outcome measure was patient-reported global response assessment. Secondary outcomes included daytime frequency, nocturia, number of urinary urgency episodes in the voiding diary, pain visual analog score, O'Leary-Sant interstitial cystitis symptom index and interstitial cystitis problem index, pelvic pain and urgency/frequency scores, risk factors for recurrence, and postoperative recurrence-free time.

RESULTS

The median duration of follow-up was 16.0 months (interquartile range 11.75-21 months). Patients who underwent modified BoNT-A injections showed significant improvement in postoperative global response assessment, symptom questionnaires, and pain assessment compared with those who underwent conventional surgery. A statistically significant difference was observed between the 2 groups in terms of recurrence-free time (12.5 vs 18.0 months, P = .02). Subgroup analysis suggested that additional PUI of BoNT-A was more effective in patients with combined severe periurethral pain. No serious complications occurred in both groups, and all minor postoperative complications were temporary.

CONCLUSION

Modified BoNT-A injection is an effective treatment for IC/BPS that significantly reduces pain and improves voiding symptoms. It is particularly effective in patients with combined periurethral pain. In such patients, PUI of BoNT-A should be added to the routine intravesical injection of BoNT-A.

Obstructive sleep apnea and bladder pain syndrome/interstitial cystitis in women

PURPOSE

The relationship between obstructive sleep apnea (OSA) and bladder pain syndrome/interstitial cystitis (BPS/IC) remains uncertain. Therefore, this study aimed to compare the frequency of BPS/IC seen in women diagnosed with OSA and in women without OSA.

MATERIAL AND METHODS

The study included a patient group of women with OSA and a control group of women without OSA. All the study participants were administered the Berlin Questionnaire, Epworth Sleepiness Scale, Interstitial Cystitis Symptom Index (ICSI), and the Interstitial Cystitis Problem Index (ICPI). Differences between the women with OSA and the control group were examined.

RESULTS

The study sample consisted of 46 women with OSA and 46 controls. No significant difference was determined between the OSA and control groups concerning age and body mass index (p = 0.810, p = 0.060, respectively). The ESS was greater in the OSA group than in the control group (p = 0.007). The median (IQR) ICSI was 8 (4-11.25) in women with OSA and 5 (1.75-7.15) in controls (p < 0.001). The median (IQR) ICPI was 7 (6.00-10.25) in women with OSA and 6 (1.75-8.00) in controls (p < 0.001).  CONCLUSIONS: The ICSI symptoms and subsequent problems in daily life caused by the symptoms (ICPI) were experienced at a higher rate in patients with OSA than in the control group. There is an association between BPS/IC and OSA.

Risk Classification for Interstitial Cystitis/Bladder Pain Syndrome Using Machine Learning Based Predictions

OBJECTIVE

To improve diagnosis of interstitial cystitis (IC)/bladder pain syndrome(IC) we hereby developed an improved IC risk classification using machine learning algorithms.

METHODS

A national crowdsourcing resulted in 1264 urine samples consisting of 536 IC (513 female, 21 male, 2 unspecified), and 728 age-matched controls (318 female, 402 male, 8 unspecified) with corresponding patient-reported outcome (PRO) pain and symptom scores. In addition, 296 urine samples were collected at three academic centers: 78 IC (71 female, 7 male) and 218 controls (148 female, 68 male, 2 unspecified). Urinary cytokine biomarker levels were determined using Luminex assay. A machine learning predictive classification model, termed the Interstitial Cystitis Personalized Inflammation Symptom (IC-PIS) Score, that utilizes PRO and cytokine levels, was generated and compared to a challenger model.

RESULTS

The top-performing model using biomarker measurements and PROs (area under the curve [AUC]=0.87) was a support vector classifier, which scored better at predicting IC than PROs alone (AUC=0.83). While biomarkers alone (AUC=0.58) did not exhibit strong predictive performance, their combination with PROs produced an improved predictive effect.

CONCLUSION

IC-PIS represents a novel classification model designed to enhance the diagnostic accuracy of IC/bladder pain syndrome by integrating PROs and urine biomarkers. The innovative approach to sample collection logistics, coupled with one of the largest crowdsourced biomarker development studies utilizing ambient shipping methods across the US, underscores the robustness and scalability of our findings.

Evaluating symptom severity and urinary cytokine levels in interstitial cystitis/bladder pain syndrome patients, with and without Hunner's lesions

PURPOSE

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a condition characterized in part by urinary urgency, frequency, and pain. There is a strong interest in gathering more data to compare and assess the differences in characteristics based on the presence of Hunner's lesions in patients with IC/BPS.

MATERIALS AND METHODS

Using a nationwide crowdsource effort, we collected surveys and urine samples from patients with a history of IC/BPS. Participants completed the Interstitial Cystitis Symptom Index (ICSI) and Problem Index (ICPI), Overactive Bladder questionnaire (OABq SF), and pain scores. In addition, participants reported any co-morbidities and lifestyle modifications. Urinary cytokine levels were measured and compared to symptom severity.

RESULTS

491 participants enrolled: 119 with history of ulcerative Hunner's lesions (UIC), 372 reported no lesions (NHIC), and 2 unknowns. 96.3% were female, and prevalence of UIC was equal for both genders. Average age was higher for UIC vs. NHIC group (P = 0.011), as was the duration since diagnosis (P < 0.001). Symptom scores were elevated in UIC patients (P < 0.001). Both groups widely implemented lifestyle modifications, with dietary changes being most prevalent (70.1%), followed by prescription medication usage (63.1%). More UIC compared to NHIC participants experienced co-morbidities (P = 0.010). Urine samples were analyzed for GRO, IL-6, IL-8, and MCP-1. MCP-1 levels were significantly higher in UIC patients (P = 0.044). Weak positive correlation was found between cytokines and symptom scores.

CONCLUSIONS

Patients with UIC and NHIC from across the United States displayed distinct phenotypic and urine biological characteristics. These findings contribute to increased understanding of IC/BPS and may aid in improving our knowledge of the condition.

Urine biomarker could be a useful tool for differential diagnosis of a lower urinary tract dysfunction

A precision diagnosis of lower urinary tract dysfunctions (LUTD) such as bladder outlet obstruction, detrusor overactivity (DO), interstitial cystitis/bladder pain syndrome (IC/BPS), dysfunctional voiding (DV), or detrusor underactivity (DU) needs invasive videourodynamic study. Exploring non-invasive tools to help screening LUTD is necessary for clinicians in their daily practice. This article reviews recently clinical studies of using urinary inflammatory proteins and oxidative stress biomarkers in the identification of specific LUTD among men and women with lower urinary tract symptoms (LUTS). Some important findings have been reported: (1) Using urine chemokines CXCL-1 and interleukin-8 (IL-8), we may discriminate overactive bladder (OAB) symptoms in women between DO and urinary tract infection. (2) Urinary levels of oxidative stress biomarkers such as 8-hydroxydeoxyguanosine (8-OHdG) and 8-isoprostane have a potential being used as a tool to identify women with mixed DO and stress urinary incontinence. (3) Urine levels of total antioxidant capacity (TAC), and prostaglandin E2 (PGE2) are positively correlated with voiding detrusor pressure in patients with DU. (4) Urine levels of brain-derived neurotrophic factor (BDNF) and PGE2 were significantly higher in the DU patients with detrusor function recovery. (5) Women with DV had higher urinary levels of tumor necrosis factor-alpha (TNF-α) and 8-OHdG, and urinary IL-2 level was significantly lower. (6) Urine level of 8-isoprostane was higher in the patients with idiopathic DO and neurogenic DO. (7) Higher urine cytokine levels of monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T-cell expressed and secreted (RANTES), CXCL-10, IL-7, and eotaxin-1 in patients with IC/BPS than controls. (8) The urine levels of IL-8, CXCL-10, BDNF, IL-6, and RANTES were significantly higher in patients with Hunner's IC than non-Hunner's IC. (9) Male patients with IC/BPS had a significantly higher level of eotaxin, MCP-1, TNF-α, 8-OHdG, and TAC. Combining a higher eotaxin and a higher TNF-α can provide a satisfactory diagnostic value in discriminating IC/BPS from other LUTD in men. These studies provide evidence that measurement of cluster of urine biomarkers could be used as a diagnostic tool to differentiate different LUTD in patients with similar LUTS.

Preparation and characterization of a novel composite acellular matrix/hyaluronic acid thermosensitive hydrogel for interstitial cystitis/bladder pain syndrome

Bladder mucosa damage that causes harm to the interstitium is a recognized pathogenesis of interstitial cystitis/bladder pain syndrome (IC/BPS). The intravesical instillation of drugs is an important second-line therapy, but it is often necessary to use drugs repeatedly in the clinic because of their short residence time in the bladder cavity, which alters the therapeutic effect. To overcome this drawback, this study developed a novel composite acellular matrix/hyaluronic acid (HA) thermosensitive hydrogel (HA-Gel) using rabbit small intestinal submucosa extracellular matrix (ECM) as the thermosensitive material and HA as the drug component and examined its composition, microstructure, thermodynamic properties, temperature sensitivity, rheological properties, biocompatibility, drug release, hydrogel residue, and bacteriostatic properties. The study showed HA-Gel was liquid at temperatures of 15-37.5°C and solid at 37.5-50°C, its swelling rate decreased with increasing temperature, and its lower critical solution temperature occurred at approximately 37.5°C. This property made the hydrogel liquid at room temperature convenient for intravesical perfusion and turned into a solid about 1 min after entering the body and rising to body temperature to increase its residence time. Subsequent experiments also proved that the gel residue time of HA-Gel in vivo and the drug release time of HA in vivo could reach more than 5 days, which was significantly higher than that of HA alone, and it had good biocompatibility and antibacterial properties. Therefore, this hydrogel possesses the proper characteristics to possibly make it an ideal dosage form for IC/BPS intravesical instillation therapy.

The urothelial barrier in interstitial cystitis/bladder pain syndrome: its form and function, an overview of preclinical models

PURPOSE OF REVIEW

Investigating bladder pain syndrome/interstitial cystitis (IC/BPS) preclinically is challenging. Various research models have been used to mimic the urothelial barrier closely and replicate the disease. The aim of this review is to discuss preclinical research related to the urothelial barrier in context of IC/BPS.

RECENT FINDINGS

In vivo models mimic IC/BPS mainly with toxic substances in the urine, with protaminesulfate and proteoglycan deglycolysation resembling a temporary impaired barrier as seen in IC/BPS. This temporary increased permeability has also been found in vitro models. Glycosaminoglycan replenishment therapy has been described, in vivo and in vitro, to protect and enhance recover properties of the urothelium. The roles of immune and neurogenic factors in the pathogenesis of IC/BPS remains relatively understudied.

SUMMARY

Preclinical studies provide opportunities to identify the involvement of specific pathologic pathways in IC/BPS. For further research is warranted to elucidate the primary or secondary role of permeability, together with inflammatory and neurogenic causes of the disease.

Bladder pain syndrome AKA interstitial cystitis - a condition with severe unmet medical need: an exploration of brimapitide as a potential treatment opportunity

PURPOSE OF REVIEW

The purpose of this article is to present recent findings of KU002 (brimapitide) as a novel treatment option for interstitial cystitis/bladder pain syndrome (IC/BPS).

RECENT FINDINGS

IC/BPS is a complex and poorly understood heterogeneous syndrome, with many burdensome symptoms that severely affect patients' quality of life. Treatment options beyond conservative and nonpharmacologic approaches remain limited, and there is an unmet medical need for effective medical treatments. While there are multiple ongoing clinical trials in this area, only a few explore new treatment options. This article summarizes current ongoing development and reports the findings of one such trial.

SUMMARY

In a phase 1/2a exploratory trial, intravesical instillation of brimapitide confirmed local action while eliciting in minimal systemic exposure, resulting in a promising and favorable safety profile. Efficacy exploration suggests that brimapitide reduces pain, improves signs and symptoms of IC/BPS and improves the general wellbeing of the study participants.

Current position of neuromodulation for bladder pain syndrome/interstitial cystitis

PURPOSE OF REVIEW

Despite established effectiveness in overactive bladder and nonobstructive retention, neuromodulation's application in interstitial cystitis/bladder pain syndrome (IC/BPS) remains a topic of ongoing research. The purpose of this article is to review recent developments in neuromodulation as treatment of IC/BPS offering guidance for healthcare practitioners dealing with IC/BPS cases.

RECENT FINDINGS

Recent research underlines the promising role of sacral, tibial and pudendal neuromodulation in management of IC/BPS symptoms. Studies reveal encouraging outcomes, particularly in alleviating urgency and frequency symptoms. However, while urgency and frequency symptoms tend to improve, comprehensive pain relief remains a challenge. Percutaneous tibial nerve stimulation (PTNS) and transcutaneous tibial nerve stimulation (TTNS) stand out due to their minimal invasive nature. Existing literature points to the need for larger prospective studies with extended follow-up periods to validate the efficacy and sustainability of neuromodulation.

SUMMARY

Neuromodulation is a promising treatment modality for refractory IC/BPS. Due to the minimal invasive nature, they should be tried before rigorous surgery. However, the limited quantity of available data and the variability in pain relief outcomes necessitate cautious interpretation. The review emphasizes the need for further research.

Intravesical Botulinum Toxin Injection Plus Hydrodistention Is More Effective in Patients with Bladder Pain-Predominant Interstitial Cystitis/Bladder Pain Syndrome

Intravesical botulinum toxin A (BoNT-A) injections are included in the interstitial cystitis/bladder pain syndrome (IC/BPS) treatment guidelines. However, the IC phenotype suitable for treatment with BoNT-A has not been clarified. Therefore, we identified the factors influencing treatment outcomes for intravesical BoNT-A injections in patients with non-Hunner IC/BPS (NHIC). This retrospective study included patients with NHIC who underwent 100 U BoNT-A intravesical injections over the past two decades. Six months after treatment, treatment outcomes were assessed using the Global Response Assessment (GRA). Outcome endpoints included GRA, clinical symptoms, urodynamic parameters, urine biomarkers, and the identification of factors contributing to satisfactory treatment outcomes. The study included 220 patients with NHIC (42 men, 178 women). The satisfactory group (n = 96, 44%) had significantly higher pain severity scores and IC symptoms index, larger maximum bladder capacity (MBC), and lower 8-isoprostane levels at baseline. Logistic regression revealed that larger MBC (≥760 mL) and bladder pain predominance were associated with satisfactory outcomes after BoNT-A injection. Subjective parameters and pain severity scores improved significantly in patients with bladder pain-predominant IC/BPS after BoNT-A injection. Thus, NHIC patients with bladder or pelvic pain are more likely to experience satisfactory outcomes following intravesical BoNT-A injections.

Efficacy and safety of intravesical dimethyl sulfoxide treatment for patients with refractory Hunner-type interstitial cystitis: Real-world data postofficial approval in Japan

OBJECTIVES

To examine real-world data regarding intravesical dimethyl sulfoxide (DMSO) therapy after official approval as a treatment for Hunner-type interstitial cystitis (HIC) in Japan.

METHODS

This single institution, retrospective observational study was conducted between 2021 and 2022 to evaluate the outcomes of 30 patients with refractory HIC who received intravesical DMSO therapy according to the approved standardized regimen: administration of DMSO every 2 weeks for a total of 12 weeks. Treatment outcomes were evaluated using a 7-graded global response assessment scale, O'Leary and Sant's symptom and problem indices (OSSI/OSPI), the overactive bladder symptom score (OABSS), an 11-point pain intensity numerical rating scale, quality of life (QOL) score, and frequency volume chart variables. Related complications were also documented.

RESULTS

The response rates at 2, 4, 6, 8, 10, and 12 weeks were 36.7%, 43.3%, 53.3%, 60.0%, 70.0%, and 70.0%, respectively. Compared with baseline, OSSI/OSPI, pain intensity, urinary frequency, and the QOL score improved significantly from 4 weeks of treatment. The OABSS score and functional bladder capacity also showed a tendency toward moderate improvement, but the difference was not significant. The mean duration of symptom relapse after termination of treatment was 6.4 ± 3.9 months. No patients discontinued treatment due to adverse events, although acute bladder irritation during infusion was noted in 21 patients (70%), which disappeared within 3 days.

CONCLUSIONS

This study verifies the safety, moderately durable efficacy, and tolerability of the standard intravesical treatment with DMSO for HIC in Japan.

Machine Learning-Based Classification of Transcriptome Signatures of Non-Ulcerative Bladder Pain Syndrome

Lower urinary tract dysfunction (LUTD) presents a global health challenge with symptoms impacting a substantial percentage of the population. The absence of reliable biomarkers complicates the accurate classification of LUTD subtypes with shared symptoms such as non-ulcerative Bladder Pain Syndrome (BPS) and overactive bladder caused by bladder outlet obstruction with Detrusor Overactivity (DO). This study introduces a machine learning (ML)-based approach for the identification of mRNA signatures specific to non-ulcerative BPS. Using next-generation sequencing (NGS) transcriptome data from bladder biopsies of patients with BPS, benign prostatic obstruction with DO, and controls, our statistical approach successfully identified 13 candidate genes capable of discerning BPS from control and DO patients. This set was validated using Quantitative Polymerase Chain Reaction (QPCR) in a larger patient cohort. To confirm our findings, we applied both supervised and unsupervised ML approaches to the QPCR dataset. A three-mRNA signature TPPP3, FAT1, and NCALD, emerged as a robust classifier for non-ulcerative BPS. The ML-based framework used to define BPS classifiers establishes a solid foundation for comprehending the gene expression changes in the bladder during BPS and serves as a valuable resource and methodology for advancing signature identification in other fields. The proposed ML pipeline demonstrates its efficacy in handling challenges associated with limited sample sizes, offering a promising avenue for applications in similar domains.

Machine Learning-based Classification of transcriptome Signatures of non-ulcerative Bladder Pain Syndrome

Lower urinary tract dysfunction (LUTD) presents a global health challenge with symptoms impacting a substantial percentage of the population. The absence of reliable biomarkers complicates the accurate classification of LUTD subtypes with shared symptoms such as non-ulcerative Bladder Pain Syndrome (BPS) and overactive bladder caused by bladder outlet obstruction with Detrusor Overactivity (DO). This study introduces a machine learning (ML)-based approach for the identification of mRNA signatures specific to non-ulcerative BPS. Using next-generation sequencing (NGS) transcriptome data from bladder biopsies of patients with BPS, benign prostatic obstruction with DO and controls, our statistical approach successfully identified 13 candidate genes capable of discerning BPS from control and DO patients. This set was subsequently validated using Quantitative Polymerase Chain Reaction (QPCR) in a larger patient cohort. To confirm our findings, we applied both supervised and unsupervised ML approaches to the QPCR dataset. Notably, a three-mRNA signature TPPP3, FAT1, and NCALD, emerged as a robust classifier, effectively distinguishing patients with non-ulcerative BPS from controls and patients with DO. This signature was universally selected by both supervised and unsupervised approaches. The ML-based framework used to define BPS classifiers not only establishes a solid foundation for comprehending the specific gene expression changes in the bladder of the patients with BPS but also serves as a valuable resource and methodology for advancing signature identification in other fields. The proposed ML pipeline demonstrates its efficacy in handling challenges associated with limited sample sizes, offering a promising avenue for applications in similar domains.

Effects of low-intensity extracorporeal shock wave therapy on lipopolysaccharide cystitis in a rat model of interstitial cystitis/bladder pain syndrome

PURPOSE

To investigate the effect of low-intensity extracorporeal shock wave therapy (LiESWT) on lipopolysaccharide (LPS)-induced cystitis in an animal model of interstitial cystitis/bladder pain syndrome (IC/BPS).

METHODS

Sprague-Dawley rats were divided into three groups: control, cystitis (LPS group, intravesical injection of LPS (1 mg) twice), and cystitis with LiESWT (LiESWT group). On the third and fourth days, LiESWT was administered (0.12 mJ/mm2, 300 shots each time) on the lower abdomen toward the bladder. On the seventh day, the rats underwent pain assessment and a metabolic cage study. Subsequently, a continuous cystometrogram (CMG) was performed under urethane anaesthesia. Immunohistochemical studies were also performed, including S-100 staining, an immunohistochemical marker of Schwann cells in the bladder.

RESULTS

In the LPS group, the pain threshold in the lower abdomen was significantly lower than that in the control group. In the metabolic cage study, the mean voided volume in the LPS group significantly increased. The CMG also revealed a significant decrease in bladder contraction amplitude, compatible with detrusor underactivity in the LPS group. Immunohistochemical studies showed inflammatory changes in the submucosa, increased fibrosis, and decreased S-100 stain-positive areas in the muscle layer of the LPS group. In the LiESWT group, tactile allodynia and bladder function were ameliorated, and S-100 stain-positive areas were increased.

CONCLUSION

By restoring nerve damage, LiESWT improved lower abdominal pain sensitivity and bladder function in an LPS-induced cystitis rat model. This study suggests that LiESWT may be a new therapeutic modality for IC/BPS.

Multimodal therapies and strategies for the treatment of interstitial cystitis/bladder pain syndrome in Taiwan

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic disease characterized by bladder pain, frequency, and nocturia. The most common pathologies include chronic inflammation and bladder urothelium dysfunction. According to the bladder condition with or without Hunner's lesions, IC/BPS can be divided into "IC" in patients with Hunner's lesion (HIC) and "BPS" in those without Hunner's lesion (NHIC). Previous studies have reported greater central sensitization and interorgan cross-talk in patients with NHIC. Multimodal treatments have been recommended in clinical guidelines under the biopsychosocial model. The bladder-gut-brain axis has also been speculated, and multimodal therapies are necessary. Unfortunately, currently, no treatment has been reported durable for IC/BPS. Patients with IC/BPS usually experience anxiety, depression, holistic physical responses, and even threats to social support systems. The lack of durable treatment outcomes might result from inadequate diagnostic accuracy and differentiation of clinical phenotypes based on the underlying pathophysiology. Precision assessment and treatment are essential for optimal therapy under definite IC/BPS phenotype. This article reviewed currently available literature and proposed a diagnosis and treatment algorithm. Based on bladder therapy combined with suitable physical and psychological therapies, a well-grounded multimodal therapy and treatment algorithm for IC/BPS following a diagnostic protocol are indispensable.

Analgesic Effect of the Kampo Formula Yokukansan via the Suppression of Substance P in an Experimental Rat Model of Hunner-Type Interstitial Cystitis

INTRODUCTION

Yokukansan (YKS), a Kampo formula used in traditional Japanese medicine, has an analgesic effect, and is used for various pain disorders. This study investigated its analgesic effects on Hunner-type interstitial cystitis (HIC) and its mechanism of action in animal models.   Methods: Rats with toll-like receptor-7 agonist (loxoribine)-induced HIC were used. Eight-week-old female Wistar rats were divided into three groups: control, HIC, and HIC-administered YKS (YKS + HIC). Bladder pain was assessed based on escape behavior using the von Frey test. Three days after HIC induction, the bladder and spinal cord were excised, and the expression of substance P (SP) was examined.   Results: The pain threshold decreased significantly in the HIC group compared to that in the control group, but this decrease was suppressed by further YKS administration. The expression of SP in the bladder wall and spinal cord increased significantly in the HIC group compared to that in the control group; however, this increase was suppressed by YKS administration.

CONCLUSION

SP is involved in the onset of bladder pain via neurokinin 1 receptors in bladder tissue. YKS may be useful for managing HIC-induced pain, and the suppression of SP secretion is one of its mechanisms of action.

Progress and challenges in intravesical drug delivery

INTRODUCTION

Intravesical drug delivery (IDD) has gained recognition as a viable approach for treating bladder-related diseases over the years. However, it comes with its set of challenges, including voiding difficulties and limitations in mucosal and epithelial penetration. These challenges lead to drug dilution and clearance, resulting in poor efficacy. Various strategies for drug delivery have been devised to overcome these issues, all aimed at optimizing drug delivery. Nevertheless, there has been minimal translation to clinical settings.

AREAS COVERED

This review provides a detailed description of IDD, including its history, advantages, and challenges. It also explores the physical barriers encountered in IDD, such as voiding, mucosal penetration, and epithelial penetration, and discusses current strategies for overcoming these challenges. Additionally, it offers a comprehensive roadmap for advancing IDD into clinical trials.

EXPERT OPINION

Physical bladder barriers and limitations of conventional treatments result in unsatisfactory efficacy against bladder diseases. Nevertheless, substantial recent efforts in this field have led to significant progress in overcoming these challenges and have raised important attributes for an optimal IDD system. However, there is still a lack of well-defined steps in the workflow to optimize the IDD system for clinical settings, and further research is required to establish more comprehensive in vitro and in vivo models to expedite clinical translation.

Cystoscopic characteristic findings of interstitial cystitis and clinical implications

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory bladder disease of unknown etiology, characterized by bladder pain and frequency urgency symptoms. Based on the cystoscopic findings after hydrodistention under anesthesia, the phenotype of IC/BPS includes no glamerulation, characteristic glomerulation, and with Hunner's lesion. IC is specifically defined if there are characteristic Hunner's lesion appeared in cystoscopy or after hydrodistention. If there are glomerulations without Hunner's lesion, BPS should be considered. The definition of Hunner's lesion and glomerulations differs based on different definition and observations. Currently, there has been no clear description and grading of the glomerulations and Hunner's lesion. Because the classification of IC/BPS has an impact on the treatment strategy and associated with therapeutic outcome, it is unmet to have a clear definition and consensus on the characteristic cystoscopic findings of IC/BPS. This article reviews the literature and presents the figures of Hunner's lesions and description of different mucosal lesions after cystoscopic hydrodistention.

Serpina3n/serpina3 alleviates cyclophosphamide-induced interstitial cystitis by activating the Wnt/β-catenin signal

BACKGROUND/OBJECTIVE

Serpina3n/Serpina3 has been identified to be implicated in inflammatory diseases, but its role in interstitial cystitis/bladder pain syndrome (IC/BPS) remains unknown. Here, we aimed to reveal serpina3n/serpina3 role in IC/BPS in vivo and in vitro.

METHODS

The IC/BPS model in mice was induced by intraperitoneal injection of 150 mg/kg of cyclophosphamide (CYP). HE and toluidine blue staining were used for histology assessment. Serpina3n/serpina3 expression in the bladder tissues from IC/BPS patients and mouse models were determined by qPCR, immunohistochemistry and western blotting. XAV-939 treatment was applied to inhibit β-catenin activation. Serpina3 role in modulating the growth and apoptosis of HBlEpCs, a human primary bladder epithelial cell line, was assessed by CCK-8 and flow cytometry assays.

RESULTS

Serpina3n/serpina3 expression was decreased in both human and mice bladder tissues with IC/BPS. Upregulation of serpina3n significantly alleviated CYP-induced bladder injury, with decreased mast cells and pro-inflammatory factor levels, including IL-1β, IL-6, and TNF-α, while increased IL-10 level. In addition, serpina3 overexpression inhibited the apoptosis of HBlEpCs, and increased cell growth. In mechanism, we found that serpina3 overexpression promoted the activation of wnt/β-catenin signaling. And, the inhibition of wnt/β-catenin signaling with XAV-939 abolished serpina3n/serpina3 role in protecting bladder tissues from CYP-induced cystitis, as well as inhibiting HBlEpC apoptosis.

CONCLUSION

Serpina3n/serpina3 expression was decreased in IC/BPS. Overexpression of serpina3n could alleviate CYP-induced IC/BPS by activating the Wnt/β-catenin signal. This study may provide a new therapeutic strategy for IC/BPS.

Emodin inhibits bladder inflammation and fibrosis in mice with interstitial cystitis by regulating JMJD3

PURPOSE

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a devastating urological chronic pelvic pain condition. In search of a potential treatment, we investigated the effect of emodin on IC/BPS inflammation and fibrosis, and explore the potential mechanism.

METHODS

An experimental model of interstitial cystitis was induced by cyclophosphamide, and human bladder smooth muscle cells were treated with lipopolysaccharide to establish the cell model in vitro. In both models, inflammation- and fibrosis-related indexes were measured after emodin administration. Furthermore, the specific antagonists were used to dig for the mechanisms underlying the response to emodin treatment.

RESULTS

Emodin significantly ameliorated management of cystitis, reduced the amount of inflammatory cytokines (tumor necrosis factor-α, monocyte chemoattractant protein-1, interleukin-1β, interleukin-8, and interleukin-6) in models, as well as reducing the synthesis of fibrosis marker including collagen1, collagen3, vimentin, fibronectin and α-smooth muscle actin. Further mechanism studies demonstrated that emodin inhibited inflammatory reaction and fibrosis through blocking lysine-specific demethylase 6B (JMJD3) expression via JAK/STAT, NF-κB and TGF-β/SMAD pathways.

CONCLUSIONS

Our study reveals the critical role of emodin-JMJD3 signaling in interstitial cystitis by regulating inflammation, fibrosis, and extracellular matrix deposition in cells and tissues, and these findings provide an avenue for effective treatment of patients with cystitis.

Cuminum cyminum Ameliorates Urotoxic Effects of Cyclophosphamide by Modulating Antioxidant, Inflammatory Cytokines, and Urinary Bladder Overactivity: In vivo and in Silico Investigations

Interstitial Cystitis (IC) is a chronic inflammatory disease that lacks effective treatment. The present study aimed to investigate the potential of aqueous ethanol extract of Cuminum cyminum (AEECC) on oxidative stress, inflammation and overactivity of urinary bladder induced by cyclophosphamide (CYP). Female Sprague-Dawley rats received intraperitoneal administration of cyclophosphamide (150 mg/kg, i. p. 1st , 4th , and 7th days). To investigate the urothelial damage, the bladder weight, nociception behavior, and Evans blue dye extravasation method was used. The antioxidants CAT, GPX and NO were measured. ELISA determined the IL-6 and TNF-α levels. The spasmolytic effect of AEECC was investigated on isolated bladder strips and its mechanisms were determined. The enhanced nociception behavior, bladder weight, vascular permeability, edema, hemorrhage, nitric oxide, IL-6 and TNF-α levels by CYP administration were significantly reduced by AEECC (250 and 500 mg/kg). A significant increase in serum antioxidant system such as CAT and GPx was also observed in AEECC-treated rats. The AEECC (3 mg/ml) significantly reduced urinary bladder tone in the strips pre-contracted with carbachol in both control and CYP-treated rats. This relaxation was demolished by atropine, nifedipine, glibenclamide, and indomethacin but not with propranolol. The plant extract showed the presence of antioxidant and anti-inflammatory phytochemicals. These results suggest that Cuminum cyminum offers uroprotective activity and can ameliorate CYP-induced bladder toxicity by modulating antioxidant parameters, pro-inflammatory cytokine levels and bladder smooth muscle overactivity. The in silico binding interactions of antioxidant 2I3Y and anti-inflammatory protein 1TNF with various ligands from Cuminum cyminum seeds revealed potential bioactive compounds with promising antioxidant and anti-inflammatory properties, providing valuable insights for drug development and nutraceutical research.

TGF-β inhibitor treatment of H₂O₂-induced cystitis models provides biochemical mechanism for elucidating interstitial cystitis/painful bladder syndrome patients

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic disease for which no effective treatment is available. Transforming growth factor-β (TGF-β) is thought to be involved in the pathogenesis of IC/PBS, and previous studies have suggested that administrations of a TGF-β inhibitor significantly ameliorated IC/PBS in a mouse model. However, the molecular mechanisms underlying the therapeutic effect of a TGF-b inhibitor on IC/PBS has not been comprehensively analyzed. TGF-β has a variety of actions, such as regulation of immune cells and fibrosis. In our study, we induced IC/PBS-like disease in mice by an intravesical administration of hydrogen peroxide (H₂O₂) and examined the effects of three TGF-β inhibitors, Repsox, SB431542, and SB505124, on the urinary functions as well as histological and gene expression profiles in the bladder. TGF-β inhibitor treatment improved urinary function and histological changes in the IC/PBS mouse model, and SB431542 was most effective among the TGF-β inhibitors. In our present study, TGF-β inhibitor treatment improved abnormal enhancement of nociceptive mechanisms, immunity and inflammation, fibrosis, and dysfunction of bladder urothelium. These results show that multiple mechanisms are involved in the improvement of urinary function by TGF-β inhibitor.

Intravesical injections of autologous platelet-rich plasma for the treatment of refractory interstitial cystitis

The urothelium acts as a barrier for the urinary bladder that prevents the influx of urinary toxic substances, electrolytes, urea nitrogen, and pathogens into the circulation. Acute or chronic inflammation of the urinary bladder may impair the regenerative function of urothelial cells and thus urothelial cell differentiation. In an inflamed bladder wall, mature apical cells are defective, resulting in impaired barrier function and thus increased urothelial permeability. This is considered to be the potential mechanism of the symptom trigger in patients with interstitial cystitis/bladder pain syndrome (IC/BPS). Previous studies have revealed that increased bladder inflammation, impaired urothelial cell maturation, a defective umbrella cell barrier, and defective junction proteins are prominent in IC/BPS bladders. Platelet-rich plasma (PRP) contains many growth factors and cytokines that are essential proteins for modulating inflammation and promoting tissue regeneration and thus wound healing. As such, PRP has been used as a regenerative therapy in many medical fields. Our preliminary studies have demonstrated that multiple intravesical PRP injections could improve symptoms in 70% of IC/BPS patients. Repeated PRP treatments also improve junctional protein, increase cytoskeleton protein expression, and decrease urinary inflammatory proteins. These preliminary results suggest that PRP injections might reduce bladder inflammation and improve urothelial cell regeneration in IC/BPS patients. This article reviews recently published clinical and basic research on the treatment potential of PRP for IC/BPS patients.

Efficacy and Safety of Low-dose Oral Prednisolone for Patients with Refractory Hunner-type Interstitial Cystitis

Background

Hunner-type interstitial cystitis (HIC) is an immunological, chronic inflammatory disease. The efficacy of corticosteroid as a treatment for HIC is unclear.

Objective

To assess the efficacy and safety of low-dose oral prednisolone (PSL) treatment for patients with refractory HIC.

Design setting and participants

This retrospective observational study reviewed the clinical outcomes of 31 patients with refractory HIC who received oral PSL daily (initial dose, 5.0 or 7.5 mg) for at least 12 mo between 2016 and 2023. The dose was tapered to the minimum that maintained symptom relief during follow-up.

Outcome measurements and statistical analysis

Treatment outcomes were evaluated using a seven-graded global response assessment (scores ≥+2, moderately or markedly improved, were defined as treatment response), O'Leary and Sant symptom and problem indices (OSSI/OSPI), overactive bladder symptom score (OABSS), an 11-point pain intensity numerical rating scale, a quality of life (QOL) score, and frequency-volume chart variables. Related complications were also documented.

Results and limitations

The mean follow-up period was 20.1 ± 14.6 mo. The overall response rates at 1, 3, 6, 9, and 12 mo at doses of 6.7, 6.7, 5.2, 4.0, and 3.0 mg were 38.7%, 48.4%, 54.8%, 61.3%, and 64.5%, respectively. Compared with baseline, OSSI/OSPI and pain intensity improved significantly from 1 mo after PSL induction. The OABSS, QOL score, urinary frequency, and voided volume improved significantly from 9 mo after PSL induction. No patients discontinued treatment due to adverse events, although hypertension and glucose intolerance occurred in two patients, but these were resolved by temporal medications.

Conclusions

This study showed that low-dose oral PSL significantly improves bladder pain, urinary symptoms, and QOL in patients with HIC, without serious adverse events. Further prospective evaluation is warranted to verify the potential efficacy and safety of low-dose PSL for HIC.

Patient summary

This retrospective observational study reviewed the clinical outcomes of 31 patients suffering from refractory Hunner-type interstitial cystitis treated with low-dose oral prednisolone. Low-dose prednisolone improved bladder pain, urinary symptoms, and quality of life significantly, without serious adverse events. The response rate of 64.5% at 12 mo was comparable with the rates reported in previous studies that used higher doses of prednisolone. This study provides a rationale for further prospective evaluation of low-dose prednisolone for this intractable disease.

Urological Tumor: A Narrative Review of Tertiary Lymphatic Structures

BACKGROUND

Tertiary lymphoid structures (TLSs), as ectopic lymphoid-like tissues, are highly similar to secondary lymphoid organs and are not only involved in chronic inflammation and autoimmune responses but are also closely associated with tumor immunotherapy and prognosis. The complex composition of the urological tumor microenvironment not only varies greatly in response to immunotherapy, but the prognostic value of TLSs in different urological tumors remains controversial.

SUMMARY

We searched PubMed, Web of Science, and other full-text database systems. TLSs, kidney cancer, uroepithelial cancer, bladder cancer, and prostate cancer as keywords, relevant literature was searched from the time the library was built to 2023. Systematically explore the role and mechanism of TLSs in urological tumors. It includes the characteristics of TLSs, the role and mechanism of TLSs in urological tumors, and the clinical significance of TLSs in urological tumors.

KEY MESSAGES

The prognostic role of TLSs in different urological tumors was significantly different. It is not only related to its enrichment in the tumor but also highly correlated with the location of the tumor. In addition, autoimmune toxicity may be a potential barrier to its role in the formation of TLSs through induction. Therefore, studying the mechanisms of TLSs in autoimmune diseases may help in the development of antitumor target drugs.

Animal models of interstitial cystitis/bladder pain syndrome

Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) is a chronic disorder characterized by pelvic and/or bladder pain, along with lower urinary tract symptoms that have a significant impact on an individual's quality of life. The diverse range of symptoms and underlying causes in IC/BPS patients pose a significant challenge for effective disease management and the development of new and effective treatments. To facilitate the development of innovative therapies for IC/BPS, numerous preclinical animal models have been developed, each focusing on distinct pathophysiological components such as localized urothelial permeability or inflammation, psychological stress, autoimmunity, and central sensitization. However, since the precise etiopathophysiology of IC/BPS remains undefined, these animal models have primarily aimed to replicate the key clinical symptoms of bladder hypersensitivity and pain to enhance the translatability of potential therapeutics. Several animal models have now been characterized to mimic the major symptoms of IC/BPS, and significant progress has been made in refining these models to induce chronic symptomatology that more closely resembles the IC/BPS phenotype. Nevertheless, it's important to note that no single model can fully replicate all aspects of the human disease. When selecting an appropriate model for preclinical therapeutic evaluation, consideration must be given to the specific pathology believed to underlie the development of IC/BPS symptoms in a particular patient group, as well as the type and severity of the model, its duration, and the proposed intervention's mechanism of action. Therefore, it is likely that different models will continue to be necessary for preclinical drug development, depending on the unique etiology of IC/BPS being investigated.

Genome-wide association study identifies risk loci within the major histocompatibility complex region for Hunner-type interstitial cystitis

Hunner-type interstitial cystitis (HIC) is a rare, chronic inflammatory disease of the urinary bladder with unknown etiology and genetic background. Here, we conduct a genome-wide association study of 144 patients with HIC and 41,516 controls of Japanese ancestry. The genetic variant, rs1794275, in the major histocompatibility complex (MHC) region (chromosome 6p21.3) is associated with HIC risk (odds ratio [OR] = 2.32; p = 3.4 × 10^-9). The association is confirmed in a replication set of 26 cases and 1,026 controls (p = 0.014). Fine mapping demonstrates the contribution to the disease risk of a completely linked haplotype of three human leukocyte antigen HLA-DQβ1 amino acid positions, 71, 74, and 75 (OR = 1.94; p = 5 × 10^-8) and of HLA-DPβ1 amino acid position 178, which tags HLA-DPB1∗04:02 (OR = 2.35; p = 7.5 × 10^-8). The three HLA-DQβ1 amino acid positions are located together at the peptide binding groove, suggesting their functional importance in antigen presentation. Our study reveals genetic contributions to HIC risk that may be associated with class II MHC molecule antigen presentation.

Scrotal Pain after Varicocelectomy: A Narrative Review

Varicocele is a frequently encountered urological disorder, which has a prevalence rate of 8 to 15% among healthy men. However, the incidence is higher in male patients with primary or secondary infertility, with up to 35 to 80% of varicocele cases occurring in this population. The clinical manifestations of varicocele typically include the presence of an asymptomatic mass that feels like a “bag of worms”, chronic scrotal pain, and infertility. Most patients with varicocele only undergo varicocelectomy after conservative treatments have failed. Unfortunately, some patients may still experience persistent scrotal pain due to a recurrence of varicocele, the development of hydrocele, neuralgia, referred pain, ureteral lesions, or nutcracker syndrome. Therefore, clinicians should consider these conditions as potential causes of postoperative scrotal pain, and take measures to address them. Several factors can assist in predicting surgical outcomes for patients with varicocele. Clinicians should consider these factors when deciding whether to perform surgery and what type of surgical intervention to use. By doing so, they can increase the likelihood of a successful surgical outcome and minimize the risk of complications such as postoperative scrotal pain.

Cannabidiol as a Promising Therapeutic Option in IC/BPS: In Vitro Evaluation of Its Protective Effects against Inflammation and Oxidative Stress

Several animal studies have described the potential effect of cannabidiol (CBD) in alleviating the symptoms of interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic inflammatory disease of the urinary bladder. However, the effects of CBD, its mechanism of action, and modulation of downstream signaling pathways in urothelial cells, the main effector cells in IC/BPS, have not been fully elucidated yet. Here, we investigated the effect of CBD against inflammation and oxidative stress in an in vitro model of IC/BPS comprised of TNFα-stimulated human urothelial cells SV-HUC1. Our results show that CBD treatment of urothelial cells significantly decreased TNFα-upregulated mRNA and protein expression of IL1α, IL8, CXCL1, and CXCL10, as well as attenuated NFκB phosphorylation. In addition, CBD treatment also diminished TNFα-driven cellular reactive oxygen species generation (ROS), by increasing the expression of the redox-sensitive transcription factor Nrf2, the antioxidant enzymes superoxide dismutase 1 and 2, and hem oxygenase 1. CBD-mediated effects in urothelial cells may occur by the activation of the PPARγ receptor since inhibition of PPARγ resulted in significantly diminished anti-inflammatory and antioxidant effects of CBD. Our observations provide new insights into the therapeutic potential of CBD through modulation of PPARγ/Nrf2/NFκB signaling pathways, which could be further exploited in the treatment of IC/BPS.

Purinergic signaling: a potential therapeutic target for depression and chronic pain

The comorbid mechanism of depression and chronic pain has been a research hotspot in recent years. Until now, the role of purinergic signals in the comorbid mechanism of depression and chronic pain has not been fully understood. This review mainly summarizes the research results published in PubMed during the past 5 years and concludes that purinergic signaling is a potential therapeutic target for comorbid depression and chronic pain, and the purinergic receptors A1, A2A, P2X3, P2X4, and P2X7and P2Y₆, P2Y₁, and P2Y₁₂ may be important factors. The main potential pathways are as follows: A1 receptor-related G protein-dependent activation of introverted K⁺ channels (GIRKs), A2A receptor-related effects on the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and MAPK/nuclear factor-κB (NF-κB) pathways, P2X3 receptor-related effects on dorsal root ganglia (DRG) excitability, P2X4 receptor-related effects on proinflammatory cytokines and inflammasome activation, P2X7 receptor-related effects on ion channels, the NLRP3 inflammasome and brain-derived neurotrophic factor (BDNF), and P2Y receptor-related effects on the phospholipase C (PLC)/inositol triphosphate (IP3)/Ca²⁺ signaling pathway. We hope that the conclusions of this review will provide key ideas for future research on the role of purinergic signaling in the comorbid mechanism of depression and chronic pain.

Deep Learning Models for Cystoscopic Recognition of Hunner Lesion in Interstitial Cystitis

Background

Accurate cystoscopic recognition of Hunner lesions (HLs) is indispensable for better treatment prognosis in managing patients with Hunner-type interstitial cystitis (HIC), but frequently challenging due to its varying appearance.

Objective

To develop a deep learning (DL) system for cystoscopic recognition of a HL using artificial intelligence (AI).

Design setting and participants

A total of 626 cystoscopic images collected from January 8, 2019 to December 24, 2020, consisting of 360 images of HLs from 41 patients with HIC and 266 images of flat reddish mucosal lesions resembling HLs from 41 control patients including those with bladder cancer and other chronic cystitis, were used to create a dataset with an 8:2 ratio of training images and test images for transfer learning and external validation, respectively. AI-based five DL models were constructed, using a pretrained convolutional neural network model that was retrained to output 1 for a HL and 0 for control. A five-fold cross-validation method was applied for internal validation.

Outcome measurements and statistical analysis

True- and false-positive rates were plotted as a receiver operating curve when the threshold changed from 0 to 1. Accuracy, sensitivity, and specificity were evaluated at a threshold of 0.5. Diagnostic performance of the models was compared with that of urologists as a reader study.

Results and limitations

The mean area under the curve of the models reached 0.919, with mean sensitivity of 81.9% and specificity of 85.2% in the test dataset. In the reader study, the mean accuracy, sensitivity, and specificity were, respectively, 83.0%, 80.4%, and 85.6% for the models, and 62.4%, 79.6%, and 45.2% for expert urologists. Limitations include the diagnostic nature of a HL as warranted assertibility.

Conclusions

We constructed the first DL system that recognizes HLs with accuracy exceeding that of humans. This AI-driven system assists physicians with proper cystoscopic recognition of a HL.

Patient summary

In this diagnostic study, we developed a deep learning system for cystoscopic recognition of Hunner lesions in patients with interstitial cystitis. The mean area under the curve of the constructed system reached 0.919 with mean sensitivity of 81.9% and specificity of 85.2%, demonstrating diagnostic accuracy exceeding that of human expert urologists in detecting Hunner lesions. This deep learning system assists physicians with proper diagnosis of a Hunner lesion.

EBV infection mediated BDNF expression is associated with bladder inflammation in interstitial cystitis/bladder pain syndrome with Hunner's lesion

Interstitial cystitis/bladder pain syndrome with Hunner's lesion (HIC) is characterized by chronic inflammation and nerve hyperplasia; however, the pathogenesis of HIC remains a mystery. In this study, we detected both Epstein-Barr virus (EBV) latency infection genes EBNA-1 and LMP-1 and EBV lytic infection BZLF-1 and BRLF-1 expression in the HIC bladders, indicating the coexistence of EBV persistence and reactivation in the B cells in HIC bladders. Upregulation of EBV-associated inflammatory genes in HIC bladders, such as TNF-α and IL-6, suggests EBV infection is implicated in the pathogenesis of bladder inflammation. Nerve hyperplasia and upregulation of brain-derived neurotrophic factor (BDNF) were noted in the HIC bladders. Double immunochemical staining and flow cytometry revealed the origin of BDNF to be EBV-infected B cells. Inducible BDNF expression was noted in B cells upon EBV infection, but not in the T cells. A chromatin immunoprecipitation study revealed BDNF transcription could be promoted by cooperation between EBV nuclear antigens, chromatin modifiers, and B-cell-specific transcription. Knockdown of BDNF in EBV-infected B cells resulted in the inhibition of cell proliferation and viability. Downregulation of phosphorylated SMAD2 and STAT3 after BDNF knockdown may play a role in the mechanism. Implantation of latent EBV-infected B cells into rat bladder walls resulted in a higher expression level of CD45 and PGP9.5, suggesting tissue inflammation and nerve hyperplasia. In contrast, implantation of BDNF depleted EBV-infected B cells abrogated these effects. This is the first study to provide insights into the mechanisms underlying the involvement of EBV-infected B cells in HIC pathogenesis. © 2022 The Pathological Society of Great Britain and Ireland.

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.

Research progress of single-cell transcriptome sequencing in autoimmune diseases and autoinflammatory disease: A review

Autoimmunity refers to the phenomenon that the body's immune system produces antibodies or sensitized lymphocytes to its own tissues to cause an immune response. Immune disorders caused by autoimmunity can mediate autoimmune diseases. Autoimmune diseases have complicated pathogenesis due to the many types of cells involved, and the mechanism is still unclear. The emergence of single-cell research technology can solve the problem that ordinary transcriptome technology cannot be accurate to cell type. It provides unbiased results through independent analysis of cells in tissues and provides more mRNA information for identifying cell subpopulations, which provides a novel approach to study disruption of immune tolerance and disturbance of pro-inflammatory pathways on a cellular basis. It may fundamentally change the understanding of molecular pathways in the pathogenesis of autoimmune diseases and develop targeted drugs. Single-cell transcriptome sequencing (scRNA-seq) has been widely applied in autoimmune diseases, which provides a powerful tool for demonstrating the cellular heterogeneity of tissues involved in various immune inflammations, identifying pathogenic cell populations, and revealing the mechanism of disease occurrence and development. This review describes the principles of scRNA-seq, introduces common sequencing platforms and practical procedures, and focuses on the progress of scRNA-seq in 41 autoimmune diseases, which include 9 systemic autoimmune diseases and autoinflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.) and 32 organ-specific autoimmune diseases (5 Skin diseases, 3 Nervous system diseases, 4 Eye diseases, 2 Respiratory system diseases, 2 Circulatory system diseases, 6 Liver, Gallbladder and Pancreas diseases, 2 Gastrointestinal system diseases, 3 Muscle, Bones and joint diseases, 3 Urinary system diseases, 2 Reproductive system diseases). This review also prospects the molecular mechanism targets of autoimmune diseases from the multi-molecular level and multi-dimensional analysis combined with single-cell multi-omics sequencing technology (such as scRNA-seq, Single cell ATAC-seq and single cell immune group library sequencing), which provides a reference for further exploring the pathogenesis and marker screening of autoimmune diseases and autoimmune inflammatory diseases in the future.

Broaden Horizons: The Advancement of Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating disease that induces mental stress, lower urinary symptoms, and pelvic pain, therefore resulting in a decline in quality of life. The present diagnoses and treatments still lead to unsatisfactory outcomes, and novel diagnostic and therapeutic modalities are needed. Although our understanding of the etiology and pathophysiology of IC/BPS is growing, the altered permeability of the impaired urothelium, the sensitized nerves on the bladder wall, and the chronic or intermittent sensory pain with inaccurate location, as well as pathologic angiogenesis, fibrosis, and Hunner lesions, all act as barriers to better diagnoses and treatments. This study aimed to summarize the comprehensive information on IC/BPS research, thereby promoting the progress of IC/BPS in the aspects of diagnosis, treatment, and prognosis. According to diverse international guidelines, the etiology of IC/BPS is associated with multiple factors, while the presence of Hunner lesions could largely distinguish the pathology, diagnosis, and treatment of non-Hunner lesions in IC/BPS patients. On the basis of the diagnosis of exclusion, the diverse present diagnostic and therapeutic procedures are undergoing a transition from a single approach to multimodal strategies targeting different potential phenotypes recommended by different guidelines. Investigations into the mechanisms involved in urinary symptoms, pain sensation, and bladder fibrosis indicate the pathophysiology of IC/BPS for further potential strategies, both in diagnosis and treatment. An overview of IC/BPS in terms of epidemiology, etiology, pathology, diagnosis, treatment, and fundamental research is provided with the latest evidence. On the basis of shared decision-making, a multimodal strategy of diagnosis and treatment targeting potential phenotypes for individual patients with IC/BPS would be of great benefit for the entire process of management. The complexity and emerging evidence on IC/BPS elicit more relevant studies and research and could optimize the management of IC/BPS patients.

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.

NLRP3+ macrophages aggravate inflammatory cystitis in diabetes

Inflammatory macrophages play a pivotal role in the progression of inflammatory cystitis. Formation of NOD-, LRR- and PYD domains-containing protein 3 (NLRP3) inflammasome triggers the activation of caspase-1/IL-1β signaling cascades to mediate inflammatory response. However, it is not known whether NLRP3 activation in macrophages during cystitis may differ in normal or diabetic setting as well as the importance of it. In this study, we found that NLRP3 levels significantly increased in bladder macrophages in diabetic mice that underwent cystitis. Moreover, bladder macrophages from diabetic mice appeared to have increased their potential of growth, migration and phagocytosis. Furthermore, specific depletion of NLRP3 in macrophages alleviated the severity of cystitis in diabetic mice, but not in non-diabetic mice. Together, our data suggest that NLRP3 depletion in macrophages may be a promising strategy for treating diabetic cystitis.

The effects of alpha-lipoic acid (ALA) on the urinary bladder injury in rats exposed to chronic stress: A histochemical study

Objective: In the present study, we aimed to investigate the morphological and biochemical effects of alpha-lipoic acid (ALA) on bladder injury caused by water avoidance stress (WAS) and to show its effect on the number of degranulated mast cells, which increase after stress. Materials and Methods: Wistar albino rats were subjected to WAS and the animals in the treatment group were injected ALA. After the urinary bladder tissues were subjected to routine tissue processing, hematoxylin-eosin staining and periodic acid-Schiff reaction were applied to observe general morphology and acidic toluidine blue method to investigate mast cells. Biochemical assessments of malondialdehyde (MDA) and glutathione (GSH) were also obtained. Transmission electron microscope was used for the ultrastructural, and scanning electron microscope for the topographical analyses. Results: The experiments showed that chronic stress caused injury in the bladder, increased degranulated and total number of mast cells and decreased GSH and increased MDA levels. ALA treatment after WAS ameliorated bladder injury in most areas, decreased degranulated and total mast cell number and increased GSH and decreased MDA levels. Conclusion: It was concluded that ALA can be a useful agent in the treatment of interstitial cystitis.

Effectiveness of intravesical ozone in interstitial cystitis by the O'Leary-Sant symptom index

Introduction and hypothesis

A prospective clinical, preliminary study was performed in patients with interstitial cystitis/bladder pain syndrome (IC/BPS) who were nonresponders to conventional treatment and received intravesical ozone as a therapeutic alternative.

Methods

Sixteen patients received six applications of intravesical ozone at a concentration of 41 μg/mL. We evaluated therapeutic efficacy by the percentage reduction of Interstitial Cystitis Symptom and Problem Index scores (ICSI/ICPI—the O'Leary–Sant symptom index), recurrence rate, nonresponse, and side effects in scores collected on admission (pre-treatment), at the end of the therapeutic protocol (post-treatment), and 180 days (follow-up) after the last ozone application.

Results

The mean age of women was 52.9 years (SD: 15.5), and the duration of symptoms was 5.7 years (SD: 7.1). The median ICSI on admission was 17 (IQR: 14.25–19.5) and at follow-up was 0.5 (IQR: 0–2), with a reduction of 97.5% (CI: 85.7–100). The median ICSI/ICPI on admission was 31.5 (IQR: 29–35.2) and at follow-up was 2.0 (IQR: 0–3.75), with a reduction of 92.3% (CI: 88.8–100). The recurrence rate was only 6.25%, and no patients were nonresponders to the treatment.

Conclusions

The application of intravesical ozone was effective in the treatment of patients with IC/BPS who were nonresponders to conventional therapy, showing a progressive and safe effect, at least in the short term.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00192-022-05383-3.

Acute Intravesical Capsaicin for the Study of TRPV1 in the Lower Urinary Tract: Clinical Relevance and Potential for Innovation

Capsaicin acts on sensory nerves via vanilloid receptors. TRPV1 has been extensively studied with respect to functional lower urinary tract (LUT) conditions in rodents and humans. We aimed to (1) provide background information on capsaicin and TRPV1 and its mechanisms of action and basis for clinical use, (2) review the use of acute intravesical capsaicin instillation (AICI) in rodents to mimic various LUT disorders in which capsaicin sensitive C-fibers are involved and (3) discuss future innovative treatments. A comprehensive search of the major literature databases until June 2022 was conducted. Both capsaicin-sensitive and resistant unmyelinated bladder afferent C-fibers are involved in non-neurogenic overactive bladder/detrusor overactivity (OAB/DO). AICI is a suitable model to study afferent hyperactivity mimicking human OAB. Capsaicin-sensitive C-fibers are also involved in neurogenic DO (NDO) and potential targets for NDO treatment. AICI has been successfully tested for NDO treatment in humans. Capsaicin-sensitive bladder afferents are targets for NDO treatment. TRPV1-immunoreactive nerve fibers are involved in the pathogenesis of interstitial cystitis/painful bladder syndrome (IC/PBS). The AICI experimental model appears relevant for the preclinical study of treatments targeting bladder afferents for refractory IC/BPS. The activity of capsaicin-sensitive bladder afferents is increased in experimental bladder outlet obstruction (BOO). The AICI model may also be relevant for bladder disorders resulting from C-fiber hyperexcitabilities related to BOO. In conclusion, there is a rationale for the selective blockade of TRPV1 channels for various bladder disorders. The AICI model is clinically relevant for the investigation of pathophysiological conditions in which bladder C-fiber afferents are overexcited and for assessing innovative treatments for bladder disorders based on their pathophysiology.

[Urodynamic and histological evaluation of cyclophosphamide-induced bladder pain syndrome in SD rats]

OBJECTIVE

To establish a model of bladder pain syndrome in SD rats by cyclophosphamide intraperitoneal injection, to evaluate the effectiveness of the model from the urodynamic and histological levels, to lay a zoological foundation for the clinical study of bladder pain syndrome, and to further guide clinical treatment.

METHODS

Thirty-two 8-week-old SD rats were randomly divided into 4 groups, including acute test group, acute control group, chronic test group, and chronic control group, with 8 rats in each group. The acute test group received intraperitoneal injection of cyclophosphamide 150 mg/kg immediately after the measurement of urodynamic data on the first day, and urodynamic examination was performed again 2 days later. After that, the rats were sacrificed to obtain bladder tissue. In the chronic test group, after measuring the baseline data of urodynamics on the first day, cyclophosphamide 75 mg/kg was intraperitoneally injected on the first, fourth, and seventh days, and the rats were sacrificed after measuring the urodynamic data again on the eighth day to obtain bladder tissue. The acute control group and the chronic control group were injected with the same amount of normal saline during intraperitoneal injection, and the urodynamic testing time point were consistent with the corresponding test groups. Histopathological changes of the bladder were assessed by HE staining.

RESULTS

In each acute and chronic group, there were no intragroup differences in baseline urodynamic levels between the test and control groups. The urodynamic maximum bladder volume was significantly reduced in the acute test group after administration(t=-2.961, P < 0.05), histologically, severe interstitial edema, obvious inflammatory cell infiltration, mucosal edema and submucosal hemorrhage, and partial urothelium were absent could be seen, which were consistent with acute cystitis performance. The urodynamic maximum bladder capacity was significantly reduced in the chronic test group after administration (t=-3.886, P < 0.05), and the bladder compliance was lower than that in the control group, but not significant, the histological manifestations were urothelial exfoliation, interstitial edema, submucosal hemorrhage, infiltration of inflammatory cells such as lymphocytes, and dense vascular distribution.

CONCLUSION

In the acute test group, a single intraperitoneal injection of cyclophosphamide could induce acute bladder inflammation in the rats. In the chronic test group, repeated injections of cyclophosphamide could induce histological changes in chronic inflammation of chronic bladder pain syndrome in the rats. But the bladder function was not significantly impaired.

Comprehensive transcriptome profiling of urothelial cells following TNFα stimulation in an in vitro interstitial cystitis/bladder pain syndrome model

Urothelial cells of the urinary bladder play a critical role in the development and progression of interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic and debilitating inflammatory disease. Given the lack of data on the exact phenotype and function of urothelial cells in an inflammatory setting (as in IC/BPS), we performed the first in-depth characterization of these cells using RNA sequencing, qPCR, ELISA, Western blot, and immunofluorescence. After TNFα stimulation, urothelial cells in the in vitro model of IC/BPS showed marked upregulation of several proinflammatory mediators, such as SAA, C3, IFNGR1, IL1α, IL1β, IL8, IL23A, IL32, CXCL1, CXCL5, CXCL10, CXCL11, TNFAIPR, TNFRSF1B, and BIRC3, involved in processes and pathways of innate immunity, including granulocyte migration and chemotaxis, inflammatory response, and complement activation, as well as TLR-, NOD-like receptor- and NFkB-signaling pathways, suggesting their active role in shaping the local immune response of the bladder. Our study demonstrates that the TNFα-stimulated urothelial cells recapitulate key observations found in the bladders of patients with IC/BPS, underpinning their utility as a suitable in vitro model for understanding IC/BPS mechanisms and confirming the role of TNFα signaling as an important component of the associated pathology. The present study also identifies novel upregulated gene targets of TNFα in urothelial cells, including genes encoding the acute phase protein SAA, complement component C3, and the cytokine receptor IFNGR1, which could be exploited as therapeutic targets of IC/BPS. Altogether, our study provides a reference database of the phenotype of urothelial cells in an inflammatory environment that will not only increase our knowledge of their role in IC/BPS, but also advance our understanding of how urothelial cells shape tissue immunity in the bladder.

INTERSTITIAL CYSTITIS AS A PLAUSIBLE CAUSE OF OVERACTIVE BLADDER IN SYSTEMIC SCLEROSIS: A HYPOTHESIS

Patients with chronic inflammatory disease of the bladder, known as interstitial cystitis (IC), tend to have autoimmune diseases, such as Sjogren’s syndrome, systemic lupus erythematosus (SLE), rheumatoid arthritis and, rarely, systemic sclerosis (SSc). SLE patients with IC are prone to present with overactive bladder (OAB) symptoms. Lower urinary tract involvement is less usual in SSc but OAB symptoms are quite common among SSc patients with lower urinary tract involvement. The underlying mechanisms of lower urinary tract involvement, including OAB, in SSc could be as follows: i) vasculopathy, ii) fibrosis and/or sclerosis of bladder wall, iii) systemic sclerosis-associated myopathy, and iv) autonomic dysfunction. However, the role of IC leading to OAB is unclear. This hypothesis suggests that in patients with SSc, OAB may be associated with IC.

Gene Expression-Based Functional Differences between the Bladder Body and Trigonal Urothelium in Adolescent Female Patients with Micturition Dysfunction

The aim of this study is to determine the molecular differences between the urothelial transcriptomes of the bladder body and trigone. The transcriptomes of the bladder body and trigonal epithelia were analyzed by massive sequencing of total epithelial RNA. The profiles of urothelial and urinal microbiomes were assessed by amplicon sequencing of bacterial 16S rRNA genes in 17 adolescent females with pain and micturition dysfunction and control female subjects. The RNA sequencing identified 10,261 differentially expressed genes (DEGs) in the urothelia of the bladder body and trigone, with the top 1000 DEGs at these locations annotated to 36 and 77 of the Reactome-related pathways in the bladder body and trigone, respectively. These pathways represented 11 categories enriched in the bladder body urothelium, including extracellular matrix organization, the neuronal system, and 15 categories enriched in the trigonal epithelium, including RHO GTPase effectors, cornified envelope formation, and neutrophil degranulation. Five bacterial taxa in urine differed significantly in patients and healthy adolescent controls. The evaluation of their transcriptomes indicated that the bladder body and trigonal urothelia were functionally different tissues. The molecular differences between the body and trigonal urothelia responsible for clinical symptoms in adolescents with bladder pain syndrome/interstitial cystitis remain unclear.

Can We Use Urinary Cytokine/Chemokine Analysis in Discriminating Ulcer-Type Interstitial Cystitis/Bladder Pain Syndrome?

Purpose: Interstitial cystitis/bladder pain syndrome (IC/BPS) has ulcer (HIC) and non-ulcer subtypes. Differentiation of these two subtypes could only be based by cystoscopy. This study analyzed the urinary cytokines and chemokines among IC/BPS subtypes and controls for discriminating HIC from non-HIC and controls. Materials and Methods: A total of 309 consecutive patients with clinically diagnosed IC/BPS were enrolled. All patients received cystoscopic hydrodistention under anesthesia and urine samples were collected prior to the procedure. Enrolled patients were classified into subtypes based on the glomerulation grade, maximal bladder capacity (MBC), and presence of Hunner’s lesion. Inflammation-related cytokines and chemokines in urine samples, including interleukin-8 (IL-8), C-X-C motif chemokine ligand 10 (CXCL10), monocyte chemoattractant protein-1 (MCP-1), brain-derived neurotrophic factor (BDNF), eotaxin-1 (eotaxin), IL-6, macrophage inflammatory protein-1 beta (MIP-1β), regulated upon activation, normally T-expressed, and presumably secreted (RANTES), tumor necrosis factor-alpha (TNF-α), and prostaglandin E2 (PGE2) were assayed using commercially available microspheres with the Milliplex® Human Cytokine/Chemokine Magnetic Bead-based Panel kit. The clinical data and urine levels of analytes between IC/BPS patients and controls, and among HIC, non-HIC, and controls were analyzed. Results: Among the 10 proteins, MCP-1, eotaxin, MIP-1β, TNF-α, and PGE2 were significantly different between IC/BPS and control, while IL-8, CXCL10, BDNF, IL-6, and RANTES were significantly higher in HIC than non-HIC patients. The receiver operating characteristic curve was used to analyze each urine biomarker in the patients with IC/BPS and controls. Among the 10 urine biomarkers, MIP-1β and TNF-α had an area under curve of >0.70 to predict IC/BPS from controls, however, the predictive values of these urine biomarkers to predict HIC from non-HIC were low. Combined cut-off values of MIP-1β and TNF-α can only have a 50% sensitivity and 39.6% specificity in identifying HIC from non-HIC. Conclusion: The results of this study demonstrate that urine cytokines and chemokines may be useful to discriminate patients with HIC from controls. An elevation of urine levels of IL-8, CXCL 10, BDNF, IL-6, and RANTES in IC/BPS patients should prompt physicians to consider the diagnosis of HIC.

Imatinib Mesylate Reduces Neurotrophic Factors and pERK and pAKT Expression in Urinary Bladder of Female Mice With Cyclophosphamide-Induced Cystitis

Imatinib mesylate is a tyrosine kinase inhibitor that inhibits platelet-derived growth factor receptor (PDGFR)-α, -β, stem cell factor receptor (c-KIT), and BCR-ABL. PDGFRα is expressed in a subset of interstitial cells in the lamina propria (LP) and detrusor muscle of the urinary bladder. PDGFRα + interstitial cells may contribute to bladder dysfunction conditions such as interstitial cystitis/bladder pain syndrome (IC/BPS) or overactive bladder (OAB). We have previously demonstrated that imatinib prevention via oral gavage or treatment via intravesical infusion improves urinary bladder function in mice with acute (4 hour, h) cyclophosphamide (CYP)-induced cystitis. Here, we investigate potential underlying mechanisms mediating the bladder functional improvement by imatinib using a prevention or treatment experimental design. Using qRT-PCR and ELISAs, we examined inflammatory mediators (NGF, VEGF, BDNF, CCL2, IL-6) previously shown to affect bladder function in CYP-induced cystitis. We also examined the distribution of phosphorylated (p) ERK and pAKT expression in the LP with immunohistochemistry. Imatinib prevention significantly (0.0001 ≤ p ≤ 0.05) reduced expression for all mediators examined except NGF, whereas imatinib treatment was without effect. Imatinib prevention and treatment significantly (0.0001 ≤ p ≤ 0.05) reduced pERK and pAKT expression in the upper LP (U. LP) and deeper LP (D. LP) in female mice with 4 h CYP-induced cystitis. Although we have previously demonstrated that imatinib prevention or treatment improves bladder function in mice with cystitis, the current studies suggest that reductions in inflammatory mediators contribute to prevention benefits of imatinib but not the treatment benefits of imatinib. Differential effects of imatinib prevention or treatment on inflammatory mediators may be influenced by the route and frequency of imatinib administration and may also suggest other mechanisms (e.g., changes in transepithelial resistance of the urothelium) through which imatinib may affect urinary bladder function following CYP-induced cystitis.