The Role of Glomerulations in Bladder Pain Syndrome: A Review

A Hypothesis for Anatomical Pathways of Chronic Pelvic Pain of "Unknown Origin"

BACKGROUND

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a disabling bladder condition. ESSIC, the IC/BPS society defines two types of IC/BPS: with Hunner's lesion (HL) and without. Pathogenesis is stated as unknown, with no cure possible. Scheffler in 2021 reported cystoscopically validated cure of HL IC/BPS by repair of uterosacral ligaments (USLs) and in 2022, Goeschen reported non-HL IC/BPS cure in 198 women following USL repair. Both Scheffler and Goeschen hypothesized IC/BPS may be a phenotype of the Integral Theory's Posterior Fornix Syndrome "PFS" (chronic pelvic pain, OAB, and emptying dysfunctions) and therefore potentially curable.

SUMMARY

The hypothesis explores whether visceral plexuses (VPs), due to weakened USLs support, serve as a primary source of pelvic pain impulses, leading to development of an inflammatory condition - for example, IC/BPS, a chronic inflammatory condition, which shares similarities with vulvodynia and complex regional pain syndrome (CRPS). According to our hypothesis, such conditions involve axon reflexes. Stimuli such as gravity applied to unsupported nerve branches within the visceral pelvic plexus, trigger centrally propagating impulses, which then progress antidromally to influence innervated tissues through cytokine release and nociceptor stimulation, perpetuating inflammatory processes at the end organs, and pain perception.

KEY MESSAGES

The hypothesis raises the question, "are IC/BPS, vulvodynia, other pain sites, even nonbacterial "chronic prostatitis" in the male, different phenotypes of the chronic pelvic pain syndrome which includes PFS. If so, the hypothesis opens several new research directions and would predict inflammatory findings in tender end organ pain sites.

A Critical Examination of Ligamentous Pathogenesis of Bladder Pain/Lower Urinary Tract Symptoms Using the UEDA Criteria

To critically analyse the relationship of bladder pain syndrome (BPS/IC), as defined, to the posterior fornix syndrome, "PFS" predictably co-occurring bladder urgency, frequency, nocturia, chronic pelvic pain, emptying symptoms/retention, caused by uterosacral ligament (USL) laxity and cured by USL repair. The starting and end points of this paper are the questions, "Are there arguments that BPS/IC can, in some cases, be linked to PFS?" And if so, "To what extent?" We used the criteria required by Ueda for proper diagnosis: "understanding symptoms, detecting abnormal findings and verifying them as a cause of the symptoms." Literature, diagnostic and surgical, indicate that chronic pelvic pain "of unknown origin" can be caused by unsupported visceral pelvic plexuses because of weak USLs; these cause fire of afferent impulses, which the brain mistakenly interprets as coming from the end-organ itself (i.e., genitourinary pain, lower urinary tract symptoms). The same lax USLs can also weaken the pelvic muscles which contract to stretch the vagina to support the urothelial stretch receptors from below: these may prematurely fire off afferent impulses to activate micturition at lower bladder volumes, interpreted as urgency. A speculum placed in the vagina can relieve pain and urgency by mechanically supporting the vaginal wall and USLs, thus predicting an eventual cure by USL repair. There is need to evaluate what percentage of women with known BPS/IC also pass the criteria for PFS. Identifying a significant percentage of BPS/IC women with the causative relation between PFS pathogenesis and BPS/ IC may open a new way of diagnosing and treating BPS/IC in some women.

Interstitial cystitis-an imbalance of risk and protective factors?

Interstitial cystitis (IC) presents as a chronic pain condition with variable combinations of symptoms depending on the species and individual patient. It is diagnosed by the presence of lower urinary tract signs and symptoms in combination with a variety of comorbid health problems, a history of life adversities, and the absence of other conditions that could cause the lower urinary tract signs. IC occurs naturally in humans and cats as a dimensional condition, with patients presenting with mild, moderate, and severe symptoms. Most patients appear to recover without specific treatment. A number of rodent models of IC have been used to study its causes and treatments. Unfortunately, current therapies generally fail to ameliorate IC symptoms long-term. The recent classification of IC as a chronic primary pain disorder calls for a rethinking of current clinical and research approaches to it. Beginning when a patient encounters a clinician, precipitating, perpetuating, and palliating risk factors can be addressed until a cause or reliably effective therapy is identified, and identifying predisposing and preventive factors can inform epidemiological studies and health promotion interventions. Predisposing, precipitating, and perpetuating risk factors, including environmental, psychological, and biological, increase the activity of the central threat response system (CTRS), which plays a clinically important role in IC symptoms. Studies in cats and rodent models have revealed that environmental enrichment (EE), in the absence of bladder-directed therapies, leads to amelioration of IC symptoms, implying a central role for the CTRS in symptom precipitation and perpetuation. Conceptually moving the source of IC pain to the brain as a motivational state rather than one resulting from peripheral nociceptive input offers both clinicians and researchers novel opportunities to improve care for patients with IC and for researchers to use more ecologically valid rodent models. It may even be that IC results from an excess of risk to protective factors, making this imbalance a targetable cause rather than a consequence of IC.

Latest insights into the pathophysiology of bladder pain syndrome/interstitial cystitis

PURPOSE OF REVIEW

Bladder pain syndrome/interstitial cystitis (BPS/IC) is a common medical problem in both sexes affecting people of all ages. Patients might report overactive bladder symptoms with additional bladder pain at maximum bladder filling, during and after micturition. This review aims to highlight pathophysiological mechanisms associated with this disease.

RECENT FINDINGS

Latest literature exposes different pathophysiological mechanisms such as impaired urothelial barrier function, alteration of urothelial factors and cytokines, chronic inflammation, vascular lesions, neurogenic inflammation and processes in the central nervous system leading to central sensitization. According to the involved mechanisms, BPS/IC may be arranged in clusters according to the clinical phenotype thus helping in clinical decision-making and treatment. Moreover, patients with BPS/IC suffer from other comorbidities such as fibromyalgia, irritable bowel syndrome, chronic pain and functional syndromes and psychosomatic diseases making the management challenging for medical professionals.

SUMMARY

Bladder pain syndrome/interstitial cystitis is a complex heterogeneous medical condition involving different pathomechanisms leading to bladder pain and dysfunction, consequently, impairing quality-of-life in affected individuals. However, these mechanisms are still not fully understood, so that patient treatments often remain unsatisfactory. For this reason, continuing research is important to understand the underlying pathomechanisms to discover biomarkers and treatment targets eventually improving diagnostic and therapeutic measures of BPS/IC.

Lower Urinary Tract Inflammation and Infection: Key Microbiological and Immunological Aspects

The urinary system, primarily responsible for the filtration of blood and waste, is affected by several infectious and inflammatory conditions. Focusing on the lower tract, this review outlines the physiological and immune landscape of the urethra and bladder, addressing key immunological and microbiological aspects of important infectious/inflammatory conditions. The conditions addressed include urethritis, interstitial cystitis/bladder pain syndrome, urinary tract infections, and urosepsis. Key aspects of each condition are addressed, including epidemiology, pathophysiology, and clinical considerations. Finally, therapeutic options are outlined, highlighting gaps in the knowledge and novel therapeutic approaches.

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.

Dehydrated Human Amnion-Chorion Membrane Extracts Can Ameliorate Interstitial Cystitis in Rats by Down-Regulating Inflammatory Cytokines and Protein Coding Genes: A Preclinical Study

The study aimed to investigate the therapeutic impact of intravesical instillation of dehydrated human amnion-chorion membrane (HACM) extracts based on the primary pathological feature of interstitial cystitis (IC). We divided 15 female Sprague-Dawley rats into three groups: sham control, IC, and treatment group. IC was induced by 400-µL lipopolysaccharide (1 µg/µL), and it was replaced with normal saline in the sham control group. After IC induction, 300 µL dehydrated HACM extracts (3 mg/kg) were instilled into rats’ urinary bladder weekly for 3 weeks. General histology, inflammatory cytokines, NF-κB, oxidative markers, and western blots results were examined. The urothelial denudation, mast-cell infiltration, and tissues fibrosis were all ameliorated. The elevated TNF-α, IL-1β, IL-6, IL-8, and NF-κB were all down-regulated by dehydrated HACM extracts (p < 0.05). For reactive oxygen species, increased malondialdehyde, decreased superoxide dismutase, and decreased glutathione peroxidase were all reversed (p < 0.05). In apoptosis of IC, elevated Bax and suppressed Bcl-2 were improved (p < 0.05) after instillation. In fibrosis, dysregulated TGFβ/R-Smads/Snail was corrected by the instillation of dehydrated HACM (p < 0.05). In conclusion, dehydrated HACM extracts could be a powerful remedy in treating IC by reconstructing the damaged urothelium, reducing mast-cell infiltration and inflammatory reactions, and ameliorating fibrotic changes.

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

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

Urinary Biomarkers in Interstitial Cystitis/Bladder Pain Syndrome and Its Impact on Therapeutic Outcome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is defined as a chronic bladder disorder with suprapubic pain (pelvic pain) and pressure and/or discomfort related to bladder filling accompanied by lower urinary tract symptoms, such as urinary frequency and urgency without urinary tract infection (UTI) lasting for at least 6 weeks. IC/BPS presents significant bladder pain and frequency urgency symptoms with unknown etiology, and it is without a widely accepted standard in diagnosis. Patients’ pathological features through cystoscopy and histologic features of bladder biopsy determine the presence or absence of Hunner lesions. IC/PBS is categorized into Hunner (ulcerative) type IC/BPS (HIC/BPS) or non-Hunner (nonulcerative) type IC/BPS (NHIC/BPS). The pathophysiology of IC/BPS is composed of multiple possible factors, such as chronic inflammation, autoimmune disorders, neurogenic hyperactivity, urothelial defects, abnormal angiogenesis, oxidative stress, and exogenous urine substances, which play a crucial role in the pathophysiology of IC/BPS. Abnormal expressions of several urine and serum specimens, including growth factor, methylhistamine, glycoprotein, chemokine and cytokines, might be useful as biomarkers for IC/BPS diagnosis. Further studies to identify the key molecules in IC/BPS will help to improve the efficacy of treatment and identify biomarkers of the disease. In this review, we discuss the potential medical therapy and assessment of therapeutic outcome with urinary biomarkers for IC/BPS.

The O'Leary-Sant Interstitial Cystitis Symptom Index is a clinically useful indicator of treatment outcome in patients with interstitial cystitis/bladder pain syndrome with Hunner lesions: A post hoc analysis of the Japanese phase III trial of KRP-116D, 50% dimethyl sulfoxide solution

OBJECTIVES

To evaluate the efficacy of intravesical KRP-116D, 50% dimethyl sulfoxide solution, in interstitial cystitis/bladder pain syndrome patients with Hunner lesions (Hunner-type interstitial cystitis), and to evaluate the correlations between efficacy variables and global response assessment to determine what constitutes a minimal clinically important change.

METHODS

We performed a post hoc analysis of the Japanese phase III trial of KRP-116D. Changes at Week 12 from baseline in objective and subjective outcomes were compared between the KRP-116D and placebo groups in Hunner-type interstitial cystitis or non-Hunner-type interstitial cystitis patients. Correlations between efficacy variables at Week 12 and global response assessment were analyzed. Area under the receiver operating characteristic curve and the cut-off value of efficacy valuables were calculated to determine clinically meaningful changes.

RESULTS

The effectiveness of intravesical treatment with KRP-116D was demonstrated in Hunner-type interstitial cystitis, but not in non-Hunner-type interstitial cystitis patients. Global response assessment was closely correlated with subjective outcomes including O'Leary-Sant Interstitial Cystitis Symptom Index, O'Leary-Sant Interstitial Cystitis Problem Index, and a numeric rating scale for bladder pain, but was less correlated with voiding variables including micturition frequency, voided volume, and maximum voided volume. In the receiver operating characteristic curve analyses, the cut-off value for the O'Leary-Sant Interstitial Cystitis Symptom Index was -5 (sensitivity 81.3%, specificity 83.3%).

CONCLUSIONS

Clinical benefit of intravesical KRP-116D in Hunner-type interstitial cystitis patients was confirmed in this post hoc analysis. A five-point reduction in O'Leary-Sant Interstitial Cystitis Symptom Index is a clinically meaningful indicator for assessing patient satisfaction with KRP-116D treatment in patients with Hunner-type interstitial cystitis.

Biomarkers in Interstitial Cystitis/Bladder Pain Syndrome with and without Hunner Lesion: A Review and Future Perspectives

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating urinary bladder condition that presents with a wide variety of clinical phenotypes. It is commonly characterized by persistent pelvic pain and lower urinary tract symptoms, such as urinary frequency and urgency. Current clinicopathological and genomic evidence has indicated that IC/BPS with Hunner lesions is a clinically relevant distinct subtype with proven bladder pathology of subepithelial chronic inflammatory changes that are characterized by enhanced local immune responses and epithelial denudation. However, other forms of IC/BPS lacking Hunner lesions are a symptom syndrome complex of non-inflammatory conditions with little evidence of bladder etiology, characterized by aberrant neural activity in neurotransmission systems which leads to central nervous sensitization with potential involvement of urothelial malfunction, or clinical presentation of somatic and/or psychological symptoms beyond the bladder. Given such distinct potential pathophysiology between IC/BPS subtypes, disease biomarkers of IC/BPS should be provided separately for subtypes with and without Hunner lesions. Tailored approaches that target characteristic immunological inflammatory processes and epithelial denudation for IC/BPS with Hunner lesions, or the sensitized/altered nervous system, urothelial malfunction, association with other functional somatic syndromes, and psychosocial problems for IC/BPS without Hunner lesions, are essential to identify optimal and reliable disease-specific IC/BPS biomarkers.

Low-pressure hydrodistension induces bladder glomerulations in female patients with interstitial cystitis/bladder pain syndrome

AIMS

The role of hydrodistension in the diagnosis of interstitial cystitis/bladder pain syndrome (IC/BPS) is controversial. This study evaluated the effect of low-pressure hydrodistension on glomerulation formation in female patients diagnosed with the disease.

METHODS

Sixty female patients with the clinical diagnosis of IC/BPS and 30 female controls without the disease underwent cystoscopy and hydrodistension. Cold-cup biopsy was taken from bladder posterior wall at sites with normal cystoscopic appearance before hydrodistension in the IC/BPS group. The tissue samples were processed for histology study. Low-pressure (40 cmH₂ O) hydrodistension for 2 min was performed and the appearance of glomerulations was compared between the two groups. High-pressure (80 cmH₂ O) hydrodistension for 8 min was then performed as a therapeutic measure for the IC/BPS patients. Further changes to the degree of glomerulations were recorded.

RESULTS

Histology showed pathological changes in the normal-appearing IC/BPS bladder mucosa including urothelium denudation, inflammatory cell infiltration, stromal edema, fibrosis, and vascular congestion. Low-pressure hydrodistension induced significant glomerulation formation in the patient group (percentage of patients with Grades 0-4: 0%, 8.3%, 40%, 35%, 10%, respectively) while none in the controls. High-pressure hydrodistension further increased the glomerulation grading in the IC/BPS patients.

CONCLUSIONS

Structural changes are present in prehydrodistension IC/BPS bladder wall, which may not be macroscopically detectable. Hydrodistension at low pressure is adequate to disrupt the integrity of such diseased mucosa and offers a more discriminative test in the diagnosis of IC/BPS.

Cystoscopic findings in women with minimal and maximal lower urinary tract symptoms

Background

Glomerulations are not specific for interstitial cystitis/bladder pain syndrome (IC/BPS). Controversy exists about whether cystoscopic findings differ between patients with and without lower urinary tract symptoms. We sought to compare the prevalence of cystoscopic findings in women with “no or minimal” urinary symptoms to those with a “high” symptom burden.

Methods

This is a secondary analysis of a prospective cohort study performed at a University Educational Facility. Participants in this study were part of a larger prospective study, in which female patients scheduled to undergo routine gynecologic procedures were all consented for cystoscopy with hydrodistension (CWHD). We defined the “minimally symptomatic group” as those with ≤1 on each of the O’Leary/Sant Interstitial Cystitis Symptom Index (ICSI) subscores and without history of IC/BPS. The “highly symptomatic” cohort of women had composite ICSI score ≥12 and a Burning/Pain subscore of 4 or 5. All were non-smokers.

Results

A total of 84 women underwent CWHD, with 33 having minimal symptoms and 51 being highly symptomatic. The two groups were not statistically different when assessing for ‘any glomerulations’ compared to ‘no glomerulations.’ However, minimally symptomatic women had an eight-fold lower prevalence of significant glomerulations than highly symptomatic women (3.0% minimally symptomatic vs. 23.5% highly symptomatic, P<0.05.)

Conclusions

Extensive glomerulations (≥10 in 3 or 4 quadrants) are rare in women with minimal urinary symptoms. These findings contrast with prior limited prospective data which quoted similar incidence of glomerulations in IC/BPS patients and asymptomatic patients. This study highlights the importance of evaluating objective evidence on CWHD and merits further investigation as part of the ongoing conversation regarding the definition of bladder health and pathology

Current Understanding and Future Perspectives of Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic disease characterized by suprapubic pain and lower urinary tract symptoms. Perhaps because of the heterogeneous nature of this disease and its multifactorial etiology, clinical trials in allinclusive populations of IC/BPS patients without phenotyping in the last decade have mainly failed to discover new therapeutic modalities of IC/BPS. Thus, phenotyping IC/BPS, aimed at identifying bladder-centric and/or bladder-beyond pathologies, including cystoscopic observation of Hunner or non-Hunner lesions of the bladder mucosa, is particularly important for the future of IC/BPS management. Based on recent discussions at international conferences, including the International Consultation on IC, Japan, it has been proposed that Hunner-lesion IC should be separated from other non-Hunner IC/BPS because of its distinct inflammatory profiles and epithelial denudation compared with non-Hunner IC/BPS. However, there are still no standard criteria for the diagnosis of Hunner lesions other than typical lesions, while conventional cystoscopic observations may miss atypical or small Hunner lesions. Furthermore, diagnosis of the bladder-centric phenotype of IC/BPS requires confirmation that identified mucosal lesions are truly a cause of bladder pain in IC/BPS patients. This review article discusses the current status of IC/BPS pathophysiology and diagnosis, as well as future directions of the proper diagnosis of bladder-centric IC/BPS, in which pathophysiological mechanisms other than those in inflammatory pathways, such as angiogenic and immunogenic abnormalities, could also be involved in both Hunner-lesion IC and non-Hunner IC/BPS. It is hoped that this new paradigm in the pathophysiological evaluation and diagnosis of IC/BPS could lead to pathology-based phenotyping and new treatments for this heterogeneous disease.

Decreased urothelial cytoskeleton and cell proliferation protein expression suggest interstitial cystitis/bladder pain syndrome patients with Hunner's lesion and grade 3 glomerulation might be different from other types of patients

OBJECTIVES

To explore the expression of cytoskeletal and cell proliferation proteins in urothelial cells of patients diagnosed with various clinical subtypes of interstitial cystitis/bladder pain syndrome.

METHODS

Biopsy specimens from 85 interstitial cystitis/bladder pain syndrome patients were classified according to findings on cystoscopy. Cytokeratins and cell proliferation proteins detected in the specimens were evaluated with immunofluorescence staining and quantified with western blotting. A total of 22 patients diagnosed with pure stress urinary incontinence were enrolled as controls.

RESULTS

Interstitial cystitis/bladder pain syndrome patients with Hunner's lesion and with grade 3 glomerulation hemorrhage had smaller bladder capacities than the other interstitial cystitis/bladder pain syndrome patients without Hunner's lesion. Diminished expression of CK14, CK20, cell proliferation protein tumor protein 63, sonic hedgehog, and fibroblast growth factor receptors 3 and 4, and increased expression of CK5 and BCL2-associated X protein were observed in biopsy specimens from patients with Hunner's lesion compared with those from patients without Hunner's lesion and controls. In the patients with grade 3 glomerulation hemorrhage, lower expression levels of urothelial CK20, tumor protein 63 and fibroblast growth factor receptor 4, and lower expression of CK5 and BCL2-associated X protein were detected compared with other types of NHIC.

CONCLUSION

A diminished expression of proliferation proteins tumor protein 63 and the mature urothelium marker CK20, and increased expression of the immature marker CK5 in specimens from both Hunner's lesion and grade 3 glomerulation hemorrhage patients can be observed. The urothelium of patients with interstitial cystitis/bladder pain syndrome might be in a state of persistent or chronic injury that could relate to the limited expression of cell proliferation proteins.

Feline Idiopathic Cystitis: Pathogenesis, Histopathology and Comparative Potential

Bladder pain syndrome (BPS) is a debilitating disease in humans, particularly women, with patients experiencing chronic, intractable, lower urinary and pelvic pain. Although rodent models have been used, feline idiopathic cystitis (FIC) is a naturally occurring bladder disease of cats that is frequently considered to be the preferred model for BPS. Histologically, FIC is most similar to the non-Hunner BPS subtype. Histology is unnecessary for the clinical diagnosis of FIC but is of great value in elucidating the pathogenesis of this disease so that prevention and therapeutic interventions can be optimized. Further study of the histological features of FIC and BPS is required to determine the significance of Von Brunn's nests, which are invaginations of hyperplastic urothelium that have been associated with irritative bladder stimuli in animals and have been observed in FIC. We review the possible pathogenesis, histopathological similarities and differences between FIC and BPS, and highlight the potential of FIC as a model of BPS.

Efficacy and safety of intravesical instillation of KRP-116D (50% dimethyl sulfoxide solution) for interstitial cystitis/bladder pain syndrome in Japanese patients: A multicenter, randomized, double-blind, placebo-controlled, clinical study

Objective

To evaluate the efficacy and safety of intravesical KRP‐116D, 50% dimethyl sulfoxide solution compared with placebo, in interstitial cystitis/bladder pain syndrome patients.

Methods

Japanese interstitial cystitis/bladder pain syndrome patients with an O’Leary‐Sant Interstitial Cystitis Symptom Index score of ≥9, who exhibited the bladder‐centric phenotype of interstitial cystitis/bladder pain syndrome diagnosed by cystoscopy and bladder‐derived pain, were enrolled. Patients were allocated to receive either KRP‐116D (n = 49) or placebo (n = 47). The study drug was intravesically administered every 2 weeks for 12 weeks.

Results

For the primary endpoint, the change in the mean O’Leary‐Sant Interstitial Cystitis Symptom Index score from baseline to week 12 was −5.2 in the KRP‐116D group and −3.4 in the placebo group. The estimated difference between the KRP‐116D and placebo groups was −1.8 (95% confidence interval −3.3, −0.3; P = 0.0188). Statistically significant improvements for KRP‐116D were also observed in the secondary endpoints including O’Leary‐Sant Interstitial Cystitis Problem Index score, micturition episodes/24 h, voided volume/micturition, maximum voided volume/micturition, numerical rating scale score for bladder pain, and global response assessment score. The adverse drug reactions were mild to moderate, and manageable.

Conclusions

This first randomized, double‐blind, placebo‐controlled trial shows that KRP‐116D improves symptoms, voiding parameters, and global response assessment, compared with placebo, and has a well‐tolerated safety profile in interstitial cystitis/bladder pain syndrome patients with the bladder‐centric phenotype.

Clinical manifestations and results of cystoscopy in women with interstitial cystitis/bladder pain syndrome

OBJECTIVE:

Interstitial cystitis/bladder pain syndrome (IC/BPS) refers to diseases that are challenging to identify, diagnose and treat. Thus, there is a need to study the clinical and cystoscopic picture of IC/BPS. The present research aims to study the clinical manifestations and results of cystoscopy with hydrodistension in women with IC/BPS.

METHODS:

One hundred twenty-six women with clinically diagnosed IC/BPS were examined – their mean age was 46.7±14.0 years. Patients were surveyed on pelvic pain and urgency/frequency patient symptom score (PUF), visual analogue scale (VAS) and urgency severity scale (USS). All patients underwent a potassium test (PST) and cystoscopy with hydrodistension. Statistical analysis was performed using SPSS software version 15.0 (SPSS Inc., Chicago, Illinois, USA).

RESULTS:

The average PUF score was 8.14±1.76 points, VAS – 5.45±0.93 points and USS – 2.63±0.91 points. A positive potassium test was detected in 91.3% of cases. The maximum average anatomical capacity of the bladder was 308.0±77.5 ml. The maximal cystometric capacity in women with mild pain was higher than among women with moderate and severe pain by 30.9% (p<0.05) and 53.0% (p<0.01), respectively. In most cases, mucosal changes were diffuse (n=57) or located in two parts of the bladder. One of the most common symptoms was the diffuse bleeding of the bladder mucosa (III degree). A statistically significant inverse correlation (r=-0.57, p<0.01) was found between the maximal cystometric bladder volume and the severity of the bladder mucosa changes. At the same time, a positive correlation was found between the severity of the bladder mucosa changes and the sum of points on the PUF questionnaire (r=+0.61, p=0.0003), the sum of points on the VAS questionnaire (r=+0.59, p=0.0008) and the USS questionnaire (r=+0.66, p=0.005).

CONCLUSION:

A relationship has been established between the clinical manifestations of IC/BPS among examined women and changes in the wall of the bladder. The data obtained from our investigation can help increase IC/BPS diagnostics and improve IC/BPS treatment results.

Presenting an atlas of Hunner lesions in interstitial cystitis which can be identified with office cystoscopy

AIM

To assist clinicians in proper visual diagnosis of Hunner lesions by providing an atlas of representative images of the variability in Hunner lesion appearance.

METHODS

Available cystoscopic images of Hunner lesions were reviewed from patients with interstitial cystitis or bladder pain syndrome (IC/BPS) treated by a single clinician between 2011 and 2020. For most patients, initial cystoscopy was performed in the office under local anesthesia. Images were categorized by variations in appearance. Data including Hunner lesion descriptions and patient demographics were retrospectively collected from the medical record. Only patients who had images available, received triamcinolone injection and/or fulguration of Hunner lesions, and reported improvement of their symptoms following treatment were included in the atlas.

RESULTS

Thirty-one IC/BPS patients with Hunner lesions had cystoscopic images available for review. We created an atlas of representative images. Variations in appearance include classic lesions with or without a central coagulum, inflamed lesions, non-inflamed lesions, groupings of lesions, and lesions with a red waterfall bleeding appearance.

CONCLUSION

There is variation in cystoscopic appearance of Hunner lesions. Most Hunner lesions can be identified during office visits using flexible cystoscopy and local anesthesia without hydrodistention or general anesthesia. Proper visual diagnosis of Hunner lesions is of upmost importance as these patients with IC/BPS respond greatly to endoscopic intervention. This atlas will serve as a reference for clinicians and researchers, so they are able to better identify and manage these patients.

Clinical characterization of interstitial cystitis/bladder pain syndrome in women based on the presence or absence of Hunner lesions and glomerulations

OBJECTIVES

To compare the clinical characteristics of three groups of female patients with interstitial cystitis/bladder pain syndrome (IC/BPS) classified according to the presence or absence of Hunner lesions (HL) and glomerulations.

METHODS

The clinical records of 100 female patients with IC/BPS who underwent their first bladder hydrodistension at our institution were retrospectively reviewed. They were divided into patients having (HL-IC; n = 57) or lacking (BPS; n = 43) HL. BPS patients were further classified as those with (29) and without (14) glomerulations. Among these three subtypes, demographics, comorbidities, symptom parameters including a visual analog scale for pain scores, O'Leary and Sant Symptom and Problem (OSSI/OSPI) Indices, frequency volume chart variables, and bladder capacity at hydrodistension were compared.

RESULTS

HL-IC patients were older and had higher OSSI/OSPI scores, greater daytime frequency and nocturia, reduced maximum and average voided volumes, and smaller bladder capacity at hydrodistension compared with BPS patients. Pain intensity and illness duration were comparable among the three groups. HL-IC patients had autoimmune disorders as comorbidities more often, but had psychiatric disorders and irritable bowel syndrome less often compared with BPS patients. No discernible differences in clinical characteristics of symptom severity and comorbid disorders were evident between BPS patients with and without glomerulations.

CONCLUSIONS

The presence of HL is associated with distinctive clinical characteristics, while glomerulations are not in female patients with IC/BPS. The presence of HL, but not glomerulations, is a robust phenotypic feature of IC/BPS in women.

Interstitial cystitis, bladder pain syndrome, hypersensitive bladder, and interstitial cystitis/bladder pain syndrome - clarification of definitions and relationships

Interstitial cystitis and interstitial cystitis-related conditions such as bladder pain syndrome and hypersensitive bladder have a similar symptomatic profile but probably different etiologies. A meaningful classification of these diseases/conditions is mandatory for clinical and investigational progress. The condition with Hunner lesions (Hunner type interstitial cystitis) is distinct from other categories in terms of histopathology, gene expression, and clinical management. Classification should clearly differentiate the presence or absence of Hunner lesions. The term covering patients as a whole should contain interstitial cystitis, since interstitial cystitis is historically a well-known name and used for insurance reimbursement. The proposed taxonomy features an umbrella term (interstitial cystitis/bladder pain syndrome) and two subgroups, Hunner type interstitial cystitis (with Hunner lesions) and bladder pain syndrome (without Hunner lesions). Interstitial cystitis/bladder pain syndrome is convenient for initial management, and subgroups can categorize the patients for specific management. The characteristic symptom profile is to be collectively termed as hypersensitive bladder symptoms.

Phenotyping of interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome is a chronic, potentially debilitating condition characterized by pain perceived to be related to the bladder in conjunction with lower urinary tract symptoms, and includes a wide variety of clinical phenotypes with diverse etiologies. Currently the only clinically relevant proven phenotype of interstitial cystitis/bladder pain syndrome is the Hunner lesion. Whether the presence of Hunner lesions is a hallmark of a distinct disease cohort or a potentially transient feature of non-Hunner lesion phenotype has been debated but remains controversial. There are few documented examples of a patient converting between the two forms. Growing clinical and basic evidence supports eliminating the Hunner lesion phenotype from the bladder pain syndrome umbrella and considering it a distinct disease. The Hunner lesion phenotype is characterized by distinct bladder histology, including subepithelial chronic inflammatory changes and epithelial denudation, and specific clinical characteristics (older onset age, severe bladder-centric symptoms, reduced bladder capacity, and favorable response to the lesion-targeted therapies). To define the Hunner lesion phenotype, it is necessary to develop an atlas of standardized images of cystoscopic (and, if possible, pathological) appearances of Hunner lesions. A true potential and clinically relevant phenotype of interstitial cystitis/bladder pain syndrome may be patients with non-bladder-centric symptoms, characterized by the affect dysregulation and somatic symptoms, and a greater bladder capacity in absence of Hunner lesions. In the present workshop, we concluded that the Hunner lesion is a valid phenotype and can reasonably be considered a disease in its own right. Assessment of bladder capacity and the extent of symptoms (bladder beyond or bladder centric) may help phenotyping of interstitial cystitis/bladder pain syndrome. Proper phenotyping is essential for the diagnosis and treatment of interstitial cystitis/bladder pain syndrome, and for facilitating research.

Relevance of the Endoscopic Evaluation in the Diagnosis of Bladder Pain Syndrome/Interstitial Cystitis

OBJECTIVE

To assess the relevance of the endoscopic evaluation in clinically suspected cases of Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC), using ESSIC criteria, established in 2008 by the European Society for the Study of Interstitial Cystitis (ESSIC).

METHODS

We included all patients who underwent endoscopic evaluation between January 01, 2015 and October 31, 2019 for clinical suspicion of BPS/IC. Collected data included demographic and baseline clinical features, endoscopic appearance (prior and after hydrodistension), and bladder wall biopsy results, both defined according to ESSIC criteria. Data were cross tabulated to define ESSIC phenotypes, while subgroups and multivariate analyses were carried out to assess the influence of clinical variables on ESSIC phenotypes.

RESULTS

Fifty-two subjects were included, mainly women (92%). Median age at evaluation was 45 (32.9-58.2) years. At hydrodistension, 21 patients (42%) had positive and 29 (58%) had negative findings. Grade 2-3 glomerulations were found in 18 patients, while Hunner lesions were reported only in 1 patient. Positive results at biopsy were found in 24 pts (51.1%), while negative in 23 (48.9%). Overall, the positive and negative concordance between hydrodistension and biopsy results was 78%. No significant differences in ESSIC subtypes were found after stratification based on clinical features and at multivariate analysis. Retrospective design is the main limitation.

CONCLUSION

Cystoscopy with hydrodistension and biopsy do have a role in the diagnostic pathway of BPS/IC. However, results should be considered in the clinical context of the individual patient.

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

Interstitial cystitis/bladder pain syndrome is a debilitating condition of unknown etiology characterized by persistent pelvic pain with lower urinary tract symptoms and comprises a wide variety of potentially clinically useful phenotypes with different possible etiologies. Current clinicopathological and genomic evidence suggests that interstitial cystitis/bladder pain syndrome should be categorized by the presence or absence of Hunner lesions, rather than by clinical phenotyping based on symptomatology. The Hunner lesion subtype is a distinct inflammatory disease with proven bladder etiology characterized by epithelial denudation and enhanced immune responses frequently accompanied by clonal expansion of infiltrating B cells, with potential engagement of infection. Meanwhile, the non-Hunner lesion subtype is a non-inflammatory disorder with little evidence of bladder etiology. It is potentially associated with urothelial malfunction and neurophysiological dysfunction, and frequently presents with somatic and/or psychological symptoms, that commonly result in central nervous sensitization. Animal models of autoimmune cystitis and neurogenic sensitization might serve as disease models for the Hunner lesion and non-Hunner lesion subtypes, respectively. Here, we revisit the taxonomy of interstitial cystitis/bladder pain syndrome according to current research, and discuss its potential pathophysiology and representative animal models. Categorization of interstitial cystitis/bladder pain syndrome based on cystoscopy is mandatory to design optimized treatment and research strategies for each subtype. A tailored approach that specifically targets the characteristic inflammation and epithelial denudation for the Hunner lesion subtype, or the urothelial malfunction, sensitized/altered nervous system and psychosocial problems for the non-Hunner lesion subtype, is essential for better clinical management and research progress in this complex condition.

Application of Adult and Pluripotent Stem Cells in Interstitial Cystitis/Bladder Pain Syndrome Therapy: Methods and Perspectives

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a multifactorial, chronic disease without definite etiology characterized by bladder-related pelvic pain. IC/BPS is associated with pain that negatively affects the quality of life. There are various therapeutic approaches against IC/BPS. However, no efficient therapeutic agent against IC/BPS has been discovered yet. Urothelium dysfunction is one of the key factors of IC/BPS-related pathogenicity. Stem cells, including adult stem cells (ASCs) and pluripotent stem cells (PSCs), such as embryonic stem cells (ESCs) and induced PSCs (iPSCs), possess the abilities of self-renewal, proliferation, and differentiation into various cell types, including urothelial and other bladder cells. Therefore, stem cells are considered robust candidates for bladder regeneration. This review provides a brief overview of the etiology, pathophysiology, diagnosis, and treatment of IC/BPS as well as a summary of ASCs and PSCs. The potential of ASCs and PSCs in bladder regeneration via differentiation into bladder cells or direct transplantation into the bladder and the possible applications in IC/BPS therapy are described in detail. A better understanding of current studies on stem cells and bladder regeneration will allow further improvement in the approaches of stem cell applications for highly efficient IC/BPS therapy.

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

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

Long-term outcome and symptom improvement in patients with interstitial cystitis/bladder pain syndrome with or without regular follow-up and treatment

AIMS

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic disease, which is difficult to treat. Patients usually seek for new therapies and might not follow-up regularly. This study investigated long-term symptom changes in patients with IC/BPS, especially in those who were lost to follow-up.

METHODS

We enrolled patients with IC/BPS with a history of >5 years and having comprehensive medical records, baseline IC symptom index and IC problem index, O'Leary-Sant symptom score, and visual analog scale (VAS). A telephone interview was conducted to assess current symptoms with the same questionnaires. A 5-point scale (from -1 to 3) was used to grade current treatment outcomes.

RESULTS

A total of 198 patients with IC/BPS with a mean age of 57.4 ± 12.2 years were included. At a mean follow-up duration of 16.6 ± 9.75 years, 12% of the patients were free of symptoms and 47% exhibited symptom improvement of more than 50%. Totally, 47 (23.7%) patients were lost to follow-up for >5 years, and 151 (76.3%) had a regular follow-up. The patients with IC/BPS who were not regularly followed up had no Hunner's lesion, and had a higher bladder volume (P = .023), higher urine flow (P = .019), and fewer comorbidities (P = .014) than those who had a regular follow-up. The number of treatment modalities was significantly less in the patients who were lost to follow-up (P = .037).

CONCLUSIONS

About half of the patients with IC/BPS exhibited symptom improvement with time, with or without regular follow-up and receiving a new treatment.

Recent advances in imaging and understanding interstitial cystitis

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating condition associated with intense pelvic pain and bladder storage symptoms. Since diagnosis is difficult, prevalence estimates vary with the methodology used. There is also a lack of proven imaging tools and biomarkers to assist in differentiation of IC/BPS from other urinary disorders (overactive bladder, vulvodynia, endometriosis, and prostatitis). Current uncertainty regarding the etiology and pathology of IC/BPS ultimately impacts its timely and successful treatment, as well as hampers future drug development. This review will cover recent developments in imaging methods, such as magnetic resonance imaging, that advance the understanding of IC/BPS and guide drug development.

Guideline of guidelines: bladder pain syndrome

OBJECTIVES

Bladder pain syndrome (BPS) is a debilitating condition which can be difficult to diagnose and treat due to the lack of consensus on aetiology, definition, and management. The aim of this review is to summarise the findings from major national and international guidelines on the management of BPS, highlighting areas of disagreement and uncertainty.

METHODS

We performed a Medline/PubMed search from 1st January 2000 to 31st December 2017 in order to identify relevant guidelines addressing BPS/interstitial cystitis. We also manually searched the websites of major national and international societies. The following guidelines were included in this review: European Association of Urology, American Urological Association, International Society for the Study of BPS, International Consultation on Incontinence, International Continence Society, East Asian guideline, Royal College of Obstetricians and Gynaecologists/British Society of Urogynaecology, and the Canadian Urological Association.

RESULTS

There is disagreement between guidelines on the exact definition of BPS and the nomenclature to use to describe this condition. However, all agree that the diagnosis is dependent on the presence of pain, pressure, or discomfort, in addition to at least one urinary symptom, in the absence of other diseases that could cause pain. Exclusion of other pathology that could cause similar symptoms requires thorough evaluation, and is recommended in all guidelines. There is also disparity in the recommended diagnostic investigation of BPS, with hydrodistension and bladder biopsy either recommended, considered optional, or not recommended, by different guidelines. It is accepted that BPS can be diagnosed clinically, without invasive investigation, but cystoscopy and diagnostic hydrodistension aids sub-typing of patients and may help direct treatment strategies. Patients should be phenotyped in order to direct multimodal treatment (including behavioural, physical, emotional, and psychological therapy), and treatments should follow a stepwise approach starting with the most conservative. Although widely performed, hydrodistension as a therapeutic strategy has a limited evidence base and is unlikely to provide long-term resolution of symptoms CONCLUSION: There are multiple national and international guidelines for the diagnosis and management of BPS, and this review has highlighted the differences in nomenclature, definitions, and recommended diagnostic tests between guidelines. The overall evidence base for the majority of treatments for BPS/IC is of low-quality, and larger randomised trials are required to more accurately inform guideline recommendations and clinical management of this complex group of patients.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

The efficacy of botulinum toxin A and sacral neuromodulation in the management of interstitial cystitis (IC)/bladder pain syndrome (BPS), what do we know? ICI-RS 2017 think thank, Bristol

AIMS

This manuscript aims to address the evidence availale in the literature on the efficacy of Botulinum Toxin A (BoNT-A) and sacral neuromodulation (SNM) in patients suffering from Interstitial Cystitis (IC)/BPS and propose further research to identify mechanisms of action and establish the clinical efficacy of either therapy.

METHODS

At the International Consultation on Incontinence-Research Society (ICI-RS) in 2017, a panel of Functional Urologists and Urogynaecologists participated in a Think Tank (TT) discussing the management of IC/BPS by BoNT-A and SNM, using available data from both PubMed and Medicine literature searches.

RESULTS

The role of BoNT-A and SNM in the treatment of IC/BPS are discussed and mechanisms of actions are proposed. Despite the available randomized trial data on the effect of intravesical BoNT-A treatment on symptoms of IC/BPS, a consistent conclusion of a positive effect cannot be drawn at the moment, as the published studies are small and heterogeneous in design. There is substantive evidence for the positive effects of SNM on symptoms of IC/BPS patients however, during patient selection, it is important to distinguish the degree and the location of pain in order to tailor the best therapy to the right patients.

CONCLUSIONS

Both intravesical BoNT-A treatment and SNM have been shown to have positive effects in patients with IC/BPS. However, firm conclusions cannot yet be drawn. Patient-reported outcomes and quality of life should be assessed in addition to urinary and pain symptoms. Since current treatments mainly focus on symptomatic relief, future research should also focus on clarifying the pathogenic mechanisms involved in IC/BPS.

Clinical guidelines for interstitial cystitis and hypersensitive bladder updated in 2015

Clinical guidelines for interstitial cystitis and hypersensitive bladder have been updated as of 2015. The guidelines define interstitial cystitis by the presence of hypersensitive bladder symptoms (discomfort, pressure or pain in the bladder usually associated with urinary frequency and nocturia) and bladder pathology, after excluding other diseases explaining symptoms. Interstitial cystitis is further classified by bladder pathology; either Hunner type interstitial cystitis with Hunner lesions or non-Hunner type interstitial cystitis with mucosal bleeding after distension in the absence of Hunner lesions. Hypersensitive bladder refers to a condition, where hypersensitive bladder symptoms are present, but bladder pathology or other explainable diseases are unproven. Interstitial cystitis and hypersensitive bladder severely affect patients' quality of life as a result of disabling symptoms and/or comorbidities. Reported prevalence suggestive of these disorders varies greatly from 0.01% to >6%. Pathophysiology would be an interaction of multiple factors including urothelial dysfunction, inflammation, neural hyperactivity, exogenous substances and extrabladder disorders. Definite diagnosis of interstitial cystitis and hypersensitive bladder requires cystoscopy with or without hydrodistension. Most of the therapeutic options lack a high level of evidence, leaving a few as recommended therapeutic options.