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

This study investigated the usefulness of urinary biomarkers for assessing bladder condition and histopathology in patients with interstitial cystitis/bladder pain syndrome (IC/BPS). We retrospectively enrolled 315 patients (267 women and 48 men) diagnosed with IC/BPS and 30 controls. Data on clinical and urodynamic characteristics (visual analog scale (VAS) score and bladder capacity) and cystoscopic hydrodistention findings (Hunner’s lesion, glomerulation grade, and maximal bladder capacity (MBC)) were recorded. Urine samples were utilized to assay inflammatory, neurogenic, and oxidative stress biomarkers, including interleukin (IL)-8, C-X-C motif chemokine ligand 10 (CXCL10), monocyte chemoattractant protein-1 (MCP-1), brain-derived neurotrophic factor (BDNF), eotaxin, IL-6, macrophage inflammatory protein 1 beta (MIP-1β), regulated on activation, normal T cell expressed and secreted (RANTES), tumor necrosis factor-alpha (TNF-α), prostaglandin E2 (PGE2), 8-hydroxy-2′-deoxyguanosine (8-OHdG), and 8-isoproatane, and total antioxidant capacity. Further, specific histopathological findings were identified via bladder biopsy. The associations between urinary biomarker levels and bladder conditions and histopathological findings were evaluated. The results reveal that patients with IC/BPS had significantly higher urinary MCP-1, eotaxin, TNF-α, PGE2, 8-OHdG, and 8-isoprostane levels than controls. Patients with Hunner’s IC (HIC) had significantly higher IL-8, CXCL10, BDNF, eotaxin, IL-6, MIP-1β, and RANTES levels than those with non-Hunner’s IC (NHIC). Patients with NHIC who had an MBC of ≤760 mL had significantly high urinary CXCL10, MCP-1, eotaxin, IL-6, MIP-1β, RANTES, PGE2, and 8-isoprostane levels and total antioxidant capacity. Patients with NHIC who had a higher glomerulation grade had significantly high urinary MCP-1, IL-6, RANTES, 8-OHdG, and 8-isoprostane levels. A significant association was observed between urinary biomarkers and glomerulation grade, MBC, VAS score, and bladder sensation. However, bladder-specific histopathological findings were not well correlated with urinary biomarker levels. The urinary biomarker levels can be useful for identifying HIC and different NHIC subtypes. Higher urinary inflammatory and oxidative stress biomarker levels are associated with IC/BPS. Most urinary biomarkers are not correlated with specific bladder histopathological findings; nevertheless, they are more important in the assessment of bladder condition than bladder histopathology.

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

Background: Interstitial cystitis/bladder pain syndrome (IC/BPS) is a condition causing bladder inflammation. Urinary biomarkers have been assessed as suitable for the diagnosis and treatment. This study aimed at investigating the role of urinary biomarkers in identifying bladder conditions and predicting the treatment outcome of IC/BPS. Methods: A total of 309 patients with IC/BPS and 30 controls were enrolled in this study. All patients underwent a comprehensive urological workup of symptoms, pain severity, and cystoscopic hydrodistention findings including maximal bladder capacity (MBC) and glomerulation grade. Urine samples were collected to investigate the levels of urinary cytokines and chemokines. According to MBC and glomerulation grade, patients with IC/BPS were further classified into the Hunner’s IC (HIC) and non-HIC groups. The urinary biomarkers between IC/BPS and control groups and HIC and non-HIC groups were compared. Moreover, the treatment response was graded according to global response assessment (GRA) scores, and urinary biomarker levels were analyzed based on different GRAs. Results: Patients with IC/BPS had significantly high urinary monocyte chemoattractant protein-1, eotaxin, tumor necrosis factor -alpha (TNF-α), and prostaglandin E2 levels. Significantly higher levels of urinary interleukin-8, C-X-C motif chemokine ligand 10 (CXCL 10), brain-derived neurotrophic factor, eotaxin, and regulated-on-activation, normal T-cell expressed and secreted (RANTES) were noted in HIC than those with non-HIC and controls. Among all biomarkers, TNF-α had the best sensitivity, specificity, positive predictive value, and negative predictive value. There was a significant correlation between biomarker levels and GRA. Conclusions: Significantly higher urine cytokines and chemokine levels were found in patients with IC/BPS. Most urinary biomarkers were significantly associated with MBC, glomerulation grade, and treatment outcome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic and debilitating condition characterized by symptoms such as bladder pain, frequent urination, and nocturia. Pain is typically perceived in the lower abdomen, pelvic floor, or urethra, causing significant discomfort and impacting quality of life. Due to the similarity of its symptoms with those of overactive bladder and acute bacterial cystitis, patients often face misdiagnosis and delayed appropriate treatment. Hunner’s (HIC) and non-Hunner’s IC (NHIC), each with distinct clinical presentations, urothelial dysfunction, chronic inflammation, and central sensitization and thus multimodal symptomatic treatment approaches, may be the most common pathogeneses of IC/BPS. Treatment of IC/BPS should involve identifying the different clinical phenotypes and underlying pathophysiology causing clinical symptoms and developing strategies tailored to the patient’s needs. This review discusses the roles of urine biomarkers, bladder inflammation, and glycosaminoglycans in the pathogenesis of IC/BPS. Various bladder treatment modalities are explored, including glycosaminoglycan replenishment, botulinum toxin A injection, platelet-rich plasma injection, low-energy shock waves, immunosuppression, and low-dose oral prednisolone. Pelvic floor muscle physiotherapy and bladder therapy combined with psychiatric consultation can help alleviate psychological stress and enhance the quality of life of patients with IC/BPS. Elucidating the pathological mechanisms and exploring diverse treatment options would help advance the care of individuals suffering from this challenging bladder condition.

Chronic pelvic pain (CPP) is defined as pain in the pelvic organs and related structures of at least 6 months’ duration. The pathophysiology of CPP is uncertain, and its treatment presents challenges. Botulinum toxin A (BoNT-A), known for its antinociceptive, anti-inflammatory, and muscle relaxant activity, has been used recently to treat refractory CPP with promising results. In patients with interstitial cystitis/bladder pain syndrome, most studies suggest intravesical BoNT-A injection reduces bladder pain and increases bladder capacity. Repeated BoNT-A injection is also effective and reduces inflammation in the bladder. Intraprostatic BoNT-A injection could significantly improve prostate pain and urinary frequency in the patients with chronic prostatitis/chronic pelvic pain syndrome. Animal studies also suggest BoNT-A injection in the prostate decreases inflammation in the prostate. Patients with CPP due to pelvic muscle pain and spasm also benefit from localized BoNT-A injections. BoNT-A injection in the pelvic floor muscle improves dyspareunia and decreases pelvic floor pressure. Preliminary studies show intravesical BoNT-A injection is useful in inflammatory bladder diseases such as chemical cystitis, radiation cystitis, and ketamine related cystitis. Dysuria is the most common adverse effect after BoNT-A injection. Very few patients develop acute urinary retention after treatment.