Urothelial Functional Protein and Sensory Receptors in Patients With Interstitial Cystitis/Bladder Pain Syndrome With and Without Hunner's Lesion

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.

Discriminating Different Bladder and Bladder Outlet Dysfunctions by Urinary Biomarkers in Women with Frequency–Urgency Syndrome

Objectives: To investigate the role of urinary biomarkers in discriminating different bladder and bladder outlet dysfunctions in women with frequency–urgency syndrome. Materials and Methods: Urine samples collected from 146 women with frequency–urgency syndrome and 34 controls were investigated. All patients were included in previous clinical trials of functional urology studies and underwent a videourodynamic study. Patients with frequency–urgency syndrome were subdivided into idiopathic detrusor overactivity (IDO), neurogenic detrusor overactivity (NDO), dysfunctional voiding (DV), and hypersensitive bladder (HSB) subgroups. Urine samples were collected before any treatment, and urinary inflammatory proteins (interleukin- (IL-) 1β, IL-2, IL-6, IL-8, tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF)), neurogenic proteins (nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and prostaglandin E2 (PGE2)), and oxidative stress biomarkers (8-isoprostane, total antioxidant capacity (TAC), and 8-hydroxydeoxyguanosine (8-OHdG)) were measured and compared between the different OAB subgroups and controls. Results: Of the 146 patients, 31 had IDO, 41 had NDO, 45 had DV, and 29 had HSB. The control group included 34 women. The patients with HSB had lower urinary TAC and IL-2 levels than the controls. The patients with IDO, NDO, and DV had significantly higher urinary TNF-α levels than those with HSB. The patients with IDO and NDO showed an increase in the urinary 8-isoprostane levels, whereas the patients with IDO had higher urinary IL-2, NGF, and BDNF levels than those with NDO. The other urinary inflammatory biomarkers did not show enough significant differences to discriminate between the different bladder and bladder outlet dysfunctions. Conclusions: The urinary levels of inflammatory, neurogenic, and oxidative stress biomarkers varied widely among the patients with bladder and bladder outlet dysfunction. This study’s results provide evidence that women with frequency–urgency syndrome and different urodynamic subtypes have varying bladder inflammation and oxidative stress conditions, which might have an impact on treatment outcomes.

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.

Current Understanding of the Pathophysiology and Novel Treatments of Interstitial Cystitis/Bladder Pain Syndrome

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.

Low-Energy Shock Wave Plus Intravesical Instillation of Botulinum Toxin A for Interstitial Cystitis/Bladder Pain Syndrome: Pathophysiology and Preliminary Result of a Novel Minimally Invasive Treatment

Low-energy shock wave (LESW) therapy is known to facilitate tissue regeneration with analgesic and anti-inflammatory effects. LESW treatment has been demonstrated to be effective in treating chronic prostatitis and pelvic pain syndrome as well as overactive bladder, and it has a potential effect on interstitial cystitis/bladder pain syndrome (IC/BPS) in humans. LESW reduces pain behavior, downregulates nerve growth factor expression, and suppresses bladder overactivity by decreasing the expression of inflammatory proteins. Previous rat IC models have shown that LESW can increase urothelial permeability, facilitate intravesical delivery of botulinum toxin A (BoNT-A), and block acetic acid-induced hyperactive bladder, suggesting that LESW might be a potential therapeutic module for relieving bladder inflammatory conditions, such as bladder oversensitivity, IC/BPS, and overactive bladder. A recent clinical trial showed that LESW monotherapy was associated with a significant reduction in pain scores and IC symptoms. BoNT-A detrusor injection or liposome-encapsulated BoNT-A instillation could also inhibit inflammation and improve IC symptoms. However, BoNT-A injection requires anesthesia and certain complications might occur. Our preliminary study using LESW plus intravesical BoNT-A instillation every week demonstrated an improvement in global response assessment without any adverse events. Moreover, an immunohistochemistry study revealed the presence of cleaved SNAP25 protein in the suburothelium of IC bladder tissue, indicating that BoNT-A could penetrate across the urothelial barrier after application of LESW. These results provide evidence for the efficacy and safety of this novel IC/BPS treatment by LESW plus BoNT-A instillation, without anesthesia, and no bladder injection. This article reviews the current evidence on LESW and LESW plus intravesical therapeutic agents on bladder disorders and the pathophysiology and pharmacological mechanism of this novel, minimally invasive treatment model for IC/BPS.

MRI as a Tool to Assess Interstitial Cystitis Associated Bladder and Brain Pathologies

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic, often incapacitating condition characterized by pain seeming to originate in the bladder in conjunction with lower urinary tract symptoms of frequency and urgency, and consists of a wide range of clinical phenotypes with diverse etiologies. There are currently no diagnostic tests for IC/BPS. Magnetic resonance imaging (MRI) is a relatively new tool to assess IC/BPS. There are several methodologies that can be applied to assess either bladder wall or brain-associated alterations in tissue morphology and/or pain. IC/BPS is commonly associated with bladder wall hyperpermeability (BWH), particularly in severe cases. Our group developed a contrast-enhanced magnetic resonance imaging (CE-MRI) approach to assess BWH in preclinical models for IC/BPS, as well as for a pilot study for IC/BPS patients. We have also used the CE-MRI approach to assess possible therapies to alleviate the BWH in preclinical models for IC/BPS, which will hopefully pave the way for future clinical trials. In addition, we have used molecular-targeted MRI (mt-MRI) to quantitatively assess BWH biomarkers. Biomarkers, such as claudin-2, may be important to assess and determine the severity of BWH, as well as to assess therapeutic efficacy. Others have also used other MRI approaches to assess the bladder wall structural alterations with diffusion-weighted imaging (DWI), by measuring changes in the apparent diffusion coefficient (ADC), diffusion tensor imaging (DTI), as well as using functional MRI (fMRI) to assess pain and morphological MRI or DWI to assess anatomical or structural changes in the brains of patients with IC/BPS. It would be beneficial if MRI-based diagnostic tests could be routinely used for these patients and possibly used to assess potential therapeutics.

Anesthetic Bladder Capacity is a Clinical Biomarker for Interstitial Cystitis/Bladder Pain Syndrome Subtypes

OBJECTIVE

To further examine anesthetic bladder capacity as a biomarker for interstitial cystitis/bladder pain syndrome (IC/BPS) patient subtypes, we evaluated demographic and clinical characteristics in a large and heterogeneous female patient cohort.

MATERIAL AND METHODS

This is a retrospective review of data from women (n = 257) diagnosed with IC/BPS who were undergoing therapeutic bladder hydrodistention (HOD). Assessments included medical history and physical examination, validated questionnaire scores, and anesthetic BC. Linear regression analyses were computed to model the relationship between anesthetic BC and patient demographic data, symptoms, and diagnoses. Variables exhibiting suggestive correlations (P ≤ .1) were candidates for a multiple linear regression analysis and were retained if significant (P ≤ .05).

RESULTS

Multiple regression analysis identified a positive correlation between BC and endometriosis (P = .028) as well as negative correlations between BC and both ICSI score (P < .001) and the presence of Hunner's lesions (P < .001). There were higher average numbers of pelvic pain syndrome (PPS) diagnoses (P = .006) and neurologic, autoimmune, or systemic pain (NASP) diagnoses (P = .003) in IC/BPS patients with a non-low BC, but no statistical difference in the duration of diagnosis between patients with low and non-low BC (P = .118).

CONCLUSION

These data, generated from a large IC/BPS patient cohort, provide additional evidence that higher BC correlates with higher numbers of non-bladder-centric syndromes while lower BC correlates more closely with bladder-specific pathology. Taken together, the results support the concept of clinical subgroups in IC/BPS.

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.

Dysregulation of bladder corticotropin-releasing hormone receptor in the pathogenesis of human interstitial cystitis/bladder pain syndrome

Stress is associated with exacerbated symptoms in patients with interstitial cystitis/bladder pain syndrome (IC/BPS). To investigate the mechanism of stress implicated on IC/BPS, we investigated expression of stress-response receptor corticotropin-releasing hormone receptor (CRHR) in bladder from IC/BPS patients. Twenty-three IC/BPS patients with Hunner’s lesion (HIC), 51 IC/BPS patients without Hunner’s lesion (NHIC), and 24 patients with stress urinary incontinence as controls were enrolled. Cystoscopic biopsies of bladder wall including mucosa and submucosa were obtained from all patients. Western blotting was used to investigate the bladder expression of the CRHR1 and CRHR2. Immunochemical staining revealed CRHR1 expression was mainly located in the submucosa while CRHR2 expression was mainly in uroepithelial cells. Compared to control subjects, the CRHR1 expression was significantly higher, while CRHR2 expression was significantly lower in IC/BPS patients. Further analysis of patients with HIC, NHIC, and control subjects showed that bladder in patients with HIC had significantly higher expressions of CRHR1 and significantly lower CRHR2. CRHR2 expression was significantly negatively correlated with O’Leary-Sant score and bladder pain. Our results indicate dysregulation of bladder CRHR1 and CRHR2 in patients with IC/BPS, and suggest CRH signaling may be associated with IC/BPS symptoms.

Long noncoding RNA (MEG3) in urinal exosomes functions as a biomarker for the diagnosis of Hunner-type interstitial cystitis (HIC)

BACKGROUND

Toll-like receptor-7 (TLR7) is functionally involved in the pathogenesis of Hunner-type interstitial cystitis (HIC). In addition, maternally expressed gene 3 (MEG3) is implicated in many urethral diseases. In this study, we aimed to verify the hypothesis that exosomal MEG3 in urine can be used as a novel diagnostic biomarker for HIC.

METHODS

Electron microscopy was utilized to observe the distribution of urinary exosomes between the case group and the control group. Receiver operating characteristic analysis was utilized to compare the diagnostic values of MEG3 and miR-19a-3p. Computational analysis and luciferase assay were conducted to identify the correlation between MEG3 and miR-19a-3p as well as between TLR7 and miR-19a-3p. In addition, real-time polymerase chain reaction and Western blot were performed to establish the signaling pathways implicated in the pathogenesis of HIC.

RESULTS

When age and gender distributions are excluded, urinary exosomes were equally distributed between case and control groups. The area under the curve of MEG3 was larger than that of miR-19a-3p, indicating that MEG3 has a better value in the diagnosis of HIC. In addition, patients with HIC showed elevated MEG3 expression and inhibited miR-19a-3p expression, thus establishing a negative correlation between MEG3 and miR-19a-3p. MEG3 and TLR7 were both identified as targets of miR-19a-3p, establishing a MEG3/miR-19a-3p/TLR7 signaling pathway, in which MEG3 enhances the expression of TLR7 via inhibiting the expression of miR-19a-3p.

CONCLUSION

MEG3 level was upregulated in patients with HIC. In addition, MEG3 downregulated miR-19a-3p expression while upregulating TLR7 expression. Furthermore, MEG3 contributes to the pathogenesis of HIC. Therefore, exosomal MEG3 in urine can be used as a biomarker for HIC diagnosis.

Mechanisms Underlying Overactive Bladder and Interstitial Cystitis/Painful Bladder Syndrome

The bladder is innervated by extrinsic afferents that project into the dorsal horn of the spinal cord, providing sensory input to the micturition centers within the central nervous system. Under normal conditions, the continuous activation of these neurons during bladder distension goes mostly unnoticed. However, for patients with chronic urological disorders such as overactive bladder syndrome (OAB) and interstitial cystitis/painful bladder syndrome (IC/PBS), exaggerated bladder sensation and altered bladder function are common debilitating symptoms. Whilst considered to be separate pathological entities, there is now significant clinical and pre-clinical evidence that both OAB and IC/PBS are related to structural, synaptic, or intrinsic changes in the complex signaling pathways that mediate bladder sensation. This review discusses how urothelial dysfunction, bladder permeability, inflammation, and cross-organ sensitisation between visceral organs can regulate this neuroplasticity. Furthermore, we discuss how the emotional affective component of pain processing, involving dysregulation of the HPA axis and maladaptation to stress, anxiety and depression, can exacerbate aberrant bladder sensation and urological dysfunction. This review reveals the complex nature of urological disorders, highlighting numerous interconnected mechanisms in their pathogenesis. To find appropriate therapeutic treatments for these disorders, it is first essential to understand the mechanisms responsible, incorporating research from every level of the sensory pathway, from bladder to brain.

Current best practice management of interstitial cystitis/bladder pain syndrome

Introduction

Over the last 100 years, the terminology and diagnosis criteria for interstitial cystitis have evolved. Many therapeutic options have changed, but others have endured. This article will review the idea of separating 'classic' Hunner lesion interstitial cystitis (HL IC) from non-Hunner lesion interstitial cystitis and bladder pain syndrome (N-HL IC/BPS) and their respective treatment algorithms.

Methods/Results

A literature search was performed to identify articles and research on HL IC and N-HL IC/BPS including definitions, etiological theories, and treatments. This article is an overview of the existing literature. We also offer insight into how HL IC and N-HL IC/BPS are approached at our tertiary referral center. Additionally, American Urological Association guidelines have been integrated and newer treatment modalities and research will be introduced at the conclusion.

Conclusion

The AUA guidelines have mapped out a stepwise fashion to treat IC/BPS; at our institution we separate patients with HL IC from those with N-HL IC/BPS prior to them entering a treatment pathway. We identify the rarer patient with HL as having classic 'IC'; this cystoscopic finding is critical in guiding treatment. We believe HL IC is a distinct disease from N-HL IC/BPS and therapy should focus on the bladder. The vast majority of patients with N-HL IC/BPS need management of their pelvic floor muscles as the primary therapy, complemented by bladder-directed therapies as needed as well as a multidisciplinary team to manage a variety of other regional/systemic symptoms. Ongoing research into IC/BPS will help us better understand the pathophysiology and phenotypes of this complex disease while exciting and novel research studies are developing promising treatments.