Targets for therapy of the painful bladder

Causal role of common autoimmune diseases in interstitial cystitis/bladder pain syndrome: Mendelian randomization (MR) study

Observational studies suggest that interstitial cystitis/bladder pain syndrome (IC/BPS) indices might be influenced by autoimmune diseases (AIDs), though it is difficult to infer causal relationships based on observational data due to risk of residual confounding. We utilized Mendelian randomization (MR) to explore causal relevance of multiple AIDs on IC/BPS. Our bidirectional two-sample MR analysis was based on summary statistics from the most recent and comprehensive genome-wide association studies. This particular approach was used to delve into the relationships of cause and effect between IC/BPS and a group of 14 AIDs. We examined a range of AIDs such as ulcerative colitis, Crohn disease, celiac disease, Sjogren syndrome, rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, primary biliary cirrhosis, psoriasis, asthma, eczema, ankylosing spondylitis, type 1 diabetes, and primary sclerosing cholangitis. Our primary analytical approach involved using the inverse variance weighting method to establish causal relationships across various AIDs and IC/BPS conditions. Furthermore, we carried out additional examinations, such as utilizing the weighted median technique, MR-Egger regression, MR-PRESSO, and evaluating reverse causality, in order to strengthen the dependability of our results. Our findings indicate a strong association between genetically predicted asthma and the risk of developing IC/BPS with a weighted odds ratio of 1.692, a confidence interval of 1.147 to 2.496, and P = .008, while the Cochran Q test P = .589 and the MR-Egger intercept test P = .554, MR-PRESSO global test P = .600. No evidence was found for causal relationships between other AIDs and IC/BPS. Individuals with asthma show an increased vulnerability to IC/BPS according to our findings. More randomized controlled trials are necessary to validate these results. These results underscore the importance for healthcare providers to assess the potential risk in asthma patients, offering a novel genetic perspective on studying interstitial cystitis.

Chronic Spontaneous Urticaria in Patients With Interstitial Cystitis/Bladder Pain Syndrome: Insights From Big Data Analyses

OBJECTIVE

To examine the association between chronic spontaneous urticaria (CSU) and interstitial cystitis/bladder pain syndrome (IC/BPS).

METHODS

A population-based retrospective cross-sectional study was performed using the Clalit Health Services medical database. The prevalence of CSU was compared between patients diagnosed with IC/BPS and age- and gender-matched controls. Univariate analysis was performed using Chi-square and Student t test and a multivariable analysis was performed using a logistic regression model.

RESULTS

The study included 681 patients with IC/BPS and 3376 demographically matched controls. The mean age of IC/BPS patients was 60 years old. The prevalence of CSU among patients with IC/BPS was higher as compared to the control group (20% vs 13.7%; P <.001). The adjusted OR for CSU in patients with IC/BPS was 1.58 (95% CI 1.28-1.97). Female gender and Jewish ethnicity were associated with the coexistence of these disorders (OR 1.7 95% CI 1.36-2.13, and 1.6 95% CI 1.28-2, respectively).

CONCLUSION

A significant association was found between IC/BPS and CSU. This finding may support the presence of allergic/immune components in the pathogenesis of IC/BPS.

Intravesical hyaluronidase causes chronic cystitis in a rat model: a potential model of bladder pain syndrome/interstitial cystitis

OBJECTIVES

To determine whether a potential rat model of bladder pain syndrome could be developed through long-term intermittent intravesical hyaluronidase.

METHODS

A total of 64 female Sprague-Dawley rats were divided into a control group, a low-dose hyaluronidase (1 mg/mL) group, a high-dose hyaluronidase (4 mg/mL) group and a hyaluronic acid-treated group. Hyaluronidase was given intravesically three times a week for 1 month. Hyaluronic acid (0.5 mL, 0.8 mg/mL) was introduced intravesically to hyaluronidase-treated rats' bladders. Histological changes, cystometry, nociceptive behaviors, and messenger ribonucleic acid levels of inflammatory factors were evaluated and compared between groups.

RESULTS

All hyaluronidase-treated rats showed chronic inflammation and fibrosis, increased and activated mast cells, thinned bladder epithelium with abnormal expressions of uroplakin III and zonula occluden-1, and increased levels of interleukin-6 and intercellular adhesion molecule-1 messenger ribonucleic acid. However, the inflammatory score and levels of interleukin-6 and intercellular adhesion molecule-1 were more significant in the high-dose hyaluronidase group than in the low-dose hyaluronidase group (P < 0.01). Furthermore, hyaluronidase-treated rats showed markedly decreased intercontraction intervals, bladder capacity and increased sensitivity to pain compared with controls (P < 0.01). Hyaluronic acid treatment significantly decreased the inflammatory level, number of mast cells, sensitivity to pain, levels of interleukin-6 and intercellular adhesion molecule-1, and increased intercontraction intervals and bladder capacity (P < 0.01).

CONCLUSIONS

Long-term intermittent intravesical hyaluronidase could develop a severe chronic cystitis with diffused fibrosis accompanied by altered histology and bladder function. This chronic cystitis rat model can resemble the clinical and histopathological features of human bladder pain syndrome, and might be a potential valuable model for investigation of this troublesome disease.

Purinoceptors as therapeutic targets for lower urinary tract dysfunction

Lower urinary tract symptoms (LUTS) are present in many common urological syndromes. However, their current suboptimal management by muscarinic and alpha(1)-adrenoceptor antagonists leaves a significant opportunity for the discovery and development of superior medicines. As potential targets for such therapeutics, purinoceptors have emerged over the last two decades from investigations that have established a prominent role for ATP in the regulation of urinary bladder function under normal and pathophysiological conditions. In particular, evidence suggests that ATP signaling via P2X(1) receptors participates in the efferent control of detrusor smooth muscle excitability, and that this function may be heightened in disease and aging. ATP also appears to be involved in bladder sensation, via activation of P2X(3) and P2X(2/3) receptors on sensory afferent neurons, both within the bladder itself and possibly at central synapses. Such findings are based on results from classical pharmacological and localization studies in non-human and human tissues, knockout mice, and studies using recently identified pharmacological antagonists--some of which possess attributes that offer the potential for optimization into candidate drug molecules. Based on recent advances in this field, it is clearly possible that the development of selective antagonists for these receptors will occur that could lead to therapies offering better relief of sensory and motor symptoms for patients, while minimizing the systemic side effects that limit current medicines.

Is interstitial cystitis an allergic disorder?: A case of interstitial cystitis treated successfully with anti-IgE

Interstitial cystitis (IC) is a chronic disorder diagnosed by symptomatology of pelvic pain and urinary frequency, which are extremely variable and unpredictable fluctuating among patients. IC has recently been found combined with some allergic disorders and histopathologic abnormalities resembling that of allergic disorders, including mast cell activation, histamine release and eosinophil infiltration. Therefore, it could be cautiously postulated that IC is one of the allergic disorders of the urogenital system. A 28-year-old Caucasian female patient, who was diagnosed with asthma and allergic rhinitis, suffered from bladder symptoms of frequency, urgency and pelvic pain for the past 3 years. The symptoms disturbed her every day and were intractable for treatment. Urologists concluded that she had interstitial cystitis. Specific immunotherapy (SIT) was recommended for her allergic symptoms. While taking specific immunotherapy, she had anaphylaxis. She still had the reaction even with the 1000-fold diluted shot of SIT. Omalizumab was used for her allergic symptoms and possible prevention of anaphylactic reaction to SIT. Interestingly, she reported that her urogenital symptoms had subsided since omalizumab had been started. According to the published literature, we postulate that interstitial cystitis might be one of the IgE mediated, mast cell driven allergic disorders of the urogenital system. Therefore, in this case, the patient's bladder symptoms are successfully controlled primarily by anti-IgE therapy and the improvement could be maintained by SIT. We report, for the first time, a case of interstitial cystitis with allergic rhinitis and asthma, successfully treated by anti-IgE therapy and specific immunotherapy.

Expression and function of bradykinin B1 and B2 receptors in normal and inflamed rat urinary bladder urothelium

The bladder urothelium exhibits dynamic sensory properties that adapt to changes in the local environment. These studies investigated the localization and function of bradykinin receptor subtypes B1 and B2 in the normal and inflamed (cyclophosphamide (CYP)-induced cystitis) bladder urothelium and their contribution to lower urinary tract function in the rat. Our findings indicate that the bradykinin 2 receptor (B2R) but not the bradykinin 1 receptor (B1R) is expressed in control bladder urothelium. B2R immunoreactivity was localized throughout the bladder, including the urothelium and detrusor smooth muscle. Bradykinin-evoked activation of this receptor elevated intracellular calcium (EC(50) = 8.4 nM) in a concentration-related manner and evoked ATP release from control cultured rat urothelial cells. In contrast, B1R mRNA was not detected in control rat urinary bladder; however, following acute (24 h) and chronic (8 day) CYP-induced cystitis in the rat, B1R mRNA was detected throughout the bladder. Functional B1Rs were demonstrated by evoking ATP release and increases in [Ca(2+)](i) in CYP (24 h)-treated cultured rat urothelial cells with a selective B1 receptor agonist (des-Arg(9)-bradykinin). Cystometry performed on control anaesthetized rats revealed that intravesical instillation of bradykinin activated the micturition pathway. Attenuation of this response by the P2 receptor antagonist PPADS suggests that bradykinin-induced micturition facilitation may be due in part to increased purinergic responsiveness. CYP (24 h)-treated rats demonstrated bladder hyperactivity that was significantly reduced by intravesical administration of either B1 (des-Arg(10)-Hoe-140) or B2 (Hoe-140) receptor antagonists. These studies demonstrate that urothelial expression of bradykinin receptors is plastic and is altered by pathology.

A prospective, double-blind, randomized cross-over study evaluating changes in urinary pH for relieving the symptoms of interstitial cystitis

OBJECTIVE

To provide evidence for the clinical efficacy of changes in urinary pH on the pain associated with interstitial cystitis (IC).

PATIENTS AND METHODS

A prospective, randomized, double-blind cross-over study was conducted with 26 women with IC between 2000 and 2002, consisting of cross-over instillations of urine at physiological pH (5.0), and neutral buffered pH (NaH(2)PO(4) buffered to pH 7.5). The outcome measured was the subjective symptom of pain assessed using a visual analogue scale at baseline, after the initial instillation of solution, at washout, and after the crossover instillation. Data were analysed using repeated-measures analysis of variance.

RESULTS

There was no statistically significant difference between the mean (sd) change from baseline pain scores after instilling neutral buffered solution, at 0.50 (2.78), and acidic solution, at 0.33 (3.43) (P = 0.85). Secondary outcomes were analysed, including baseline variability and treatment-order effects; neither were significantly different between the groups.

CONCLUSIONS

There was no statistically significant difference in subjective pain scores on instilling urine at physiological pH or sodium-phosphate buffered saline in these patients with IC. Further work is required to define the role, if any, of urinary pH in the pathophysiology and treatment of IC.

Interstitial cystitis

Interstitial cystitis (IC) is a debilitating chronic inflammatory disorder of the bladder. It affects predominantly middle-aged Caucasian women. The diagnosis, made from the combination of symptoms, cystoscopic findings and bladder biopsies, is often delayed in the gynaecology setting because of a low index of suspicion. The pathophysiology is incompletely understood, although mast cell activation, altered bladder epithelial permeability and sensory afferent nerve up-regulation are thought to play key roles. Recent theories include the role of an antiproliferative factor. A wide assortment of therapies is available and many more are under trial. Until the causes and pathogenesis of IC are unraveled, mainstream medical treatment will remain palliative and cystectomy with urinary diversion, the only potential cure. In addition to our long experience on managing this disorder, we present a comprehensive review of the current thoughts on the aetiology and management of IC.

Recent developments in the management of interstitial cystitis

PURPOSE OF REVIEW

Interstitial cystitis, a great enigma of urology today, is a chronic sterile inflammatory disease of the bladder of unknown etiology characterized by urinary frequency, urgency, nocturia and suprapubic pain. Although there are plenty of theories, the etiology of the condition remains obscure. This review focuses on recently published literature on interstitial cystitis.

RECENT FINDINGS

Several pathophysiological mechanisms have been proposed in the past few years including epithelial dysfunction, activation of mast cells, neurogenic inflammation, autoimmunity and occult infection. Evidence indicates that it is a heterogeneous syndrome and that the two subtypes, classic and nonulcer disease, represent different entities. The diagnosis is made by clinical and cystoscopic evaluation with hydrodistension and often with biopsy when other disorders are excluded. The National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases has developed criteria for clinical studies. There is a need for a noninvasive marker of interstitial cystitis. Antiproliferative factor as a urinary marker has shown promising results. The value of the bladder permeability test in interstitial cystitis needs further investigation. Many gynecologic conditions mimic the symptoms of interstitial cystitis. Multiple forms of therapy are available including self-care and dietary changes, medical and intravesical treatments, neuromodulation, multimodality treatment and surgical intervention. It is recommended that the most conservative treatments are used first and surgery should be regarded as the last resort.

SUMMARY

Interstitial cystitis is a challenging disease of urology today. While causative factors remain unknown, treatment is based on empiricism. Intensive research may result in new and hopefully more effective treatments in the future.