Chronic Bladder Inflammation Research Articles

The serotonin(5-HT)2A receptor is involved in the hypersensitivity of bladder afferent neurons in cyclophosphamide-induced cystitis

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic bladder inflammation characterized by the main symptoms of urinary frequency, urgency, and pelvic pain. The hypersensitivity of bladder afferent neurons is considered a significant pathophysiologic mechanism in IC/PBS. Serotonin (5-HT, 5-hydroxytryptamine) receptors are known to be involved in the regulation of the micturition reflex and hyperalgesia, but the effect of 5-HT receptors on cystitis remains unknown. In this study, a rat model of interstitial cystitis induced by intraperitoneal injection of cyclophosphamide (CYP) was used to investigate the role of 5-HT receptors on cystitis. The histology and urodynamics exhibited chronic cystitis and overactive bladder in CYP-treated rats. Notably, among 5-HT1A, 5-HT2A and 5-HT7 receptors, the expression of 5-HT2A receptor was significantly increased in bladder afferent neurons in CYP-treated rats. Intrathecal administration of the 5-HT2A receptor antagonist M100907 could alleviate bladder overactivity and hyperalgesia in CYP-induced cystitis rats. Neuronal calcium imaging of bladder afferent neurons revealed increased calcium influx induced by the 5-HT2A receptor agonist or capsaicin in cystitis rats, which could be inhibited by M100907. Moreover, RNA sequencing indicated that differentially expressed genes were enriched in inflammation-related pathways and cellular calcium homeostasis. These findings suggest that the 5-HT2A receptor is involved in the hypersensitivity of bladder afferent neurons in CYP-induced cystitis, and M100907 could alleviate bladder overactivity and hyperalgesia in CYP-induced cystitis by inhibiting neuronal hypersensitivity in the afferent pathways. The 5-HT2A receptor may be a potential therapeutic target for the treatment of IC/BPS.

Hispidulin targets PTGS2 to improve cyclophosphamide-induced cystitis by suppressing NLRP3 inflammasome.

Interstitial cystitis (IC) is a chronic bladder inflammation. Inhibition of prostaglandin G/H synthase 2 (PTGS2) is the most common method for controlling inflammation-related diseases. This study aimed to analyze the effects of hispidulin on the PTGS2 and NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammation in experimental IC models. A binding activity between hispidulin and PTGS2 was measured using molecular docking. Human urothelial cells (SV-HUC-1) were stimulated by 2ng/mL of interleukin (IL)-1β for 24h and cultured in a medium with different concentrations of hispidulin (2.5, 5, 10, 20µM) for 24h to observe the expressions of PTGS2 and NLRP3 protein. Cells overexpressing PTGS2 were established by PTGS2 cDNA transfection. In the IL-1β-treated cells, the NLRP3 inflammasome was measured after 20µM hispidulin treatment. In rats, animals were performed with three injections of 40mg/kg cyclophosphamide (CYP) and orally treated with 50mg/kg/day hispidulin or ibuprofen for 3days. The bladder pain was measured using Von Frey filaments, and the bladder pathology was observed using hematoxylin and eosin (H&E) staining. The expressions of PTGS2 and NLRP3 inflammasome were also observed in the bladder tissues. A good binding activity was found between hispidulin and PTGS2 (score = - 8.9kcal/mol). The levels of PTGS2 and NLRP3 inflammasome were decreased with the hispidulin dose increase in the IL-1β-treated cells (p < 0.05). Cells overexpressing PTGS2 weakened the protective effects of hispidulin in the IL-1β-treated cells (p < 0.01). In the CYP-treated rats, hispidulin treatment improved the bladder pain through decreasing the nociceptive score (p < 0.01) and suppressed the bladder inflammation through suppressing the expressions of PTGS2 and NLRP3 inflammasome in bladder tissues (p < 0.01). Additionally, the results of ibuprofen treatment were similar to the effects of hispidulin in the CYP-treated rats. This study demonstrates that hispidulin may be a new alternative drug for the IC treatment that binds PTGS2 to perform its functions.

Sex-Dependent Differences in Blood-Urine Barrier Are Subtle but Significant in Healthy and Chronically Inflamed Mouse Bladders.

The urothelium is a vital permeability barrier that prevents the uncontrolled flow of urinary components into and out of the bladder interstitium. Our study addressed the question of possible sex-specific variations in the urothelium of healthy mice and their impact on chronic bladder inflammation. We found that healthy female bladders have a less robust barrier function than male bladders, as indicated by significant differences in transepithelial electrical resistance (TEER) values. These differences could be attributed to detected higher claudin 2 mRNA expression and a less pronounced glycocalyx in females than in males. In addition, TEER measurements showed delayed barrier recovery in chronically inflamed female bladders. We found subtle differences in the expressions of genes involved in the regulation of the actin cytoskeleton between the sexes, as well as pronounced urothelial hyperplasia in females compensating for attenuated barrier function. The identified genetic variations in glycosylation pathways may also contribute to this divergence. Our findings add to the growing body of literature on the intricate sex-specific nuances of urothelial permeability function and their implications for chronic bladder inflammation. Understanding these differences could lead to tailored diagnostic and therapeutic approaches in the treatment of bladder disorders in the future.

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.

A Study of DNA Methylation of Bladder Cancer Biomarkers in the Urine of Patients with Neurogenic Lower Urinary Tract Dysfunction.

Background: Bladder cancer (BCa) in patients suffering from neurogenic lower urinary tract dysfunction (NLUTD) is a significant concern due to its advanced stage at diagnosis and high mortality rate. Currently, there is a scarcity of specific guidelines for BCa screening in these patients. The development of urine biomarkers for BCa seems to be an attractive non-invasive method of screening or risk stratification in this patient population. DNA methylation is an epigenetic modification, resulting in the transcriptional silencing of tumor suppression genes, that is frequently detected in the urine of BCa patients. Objectives: We aimed to investigate DNA hypermethylation in five gene promoters, previously associated with BCa, in the urine of NLUTD patients, and in comparison with healthy controls. Design, setting and participants: This was a prospective case-control study that recruited neurourology outpatients from a public teaching hospital who had suffered from NLUTD for at least 5 years. They all underwent cystoscopy combined with biopsy for BCa screening following written informed consent. DNA was extracted and DNA methylation was assessed for the RASSF1, RARβ, DAPK, TERT and APC gene promoters via quantitative methylation-specific PCR in urine specimens from the patients and controls. Results: Forty-one patients of mixed NLUTD etiology and 35 controls were enrolled. DNA was detected in 36 patients' urine specimens and in those of 22 controls. In the urine specimens, DNA was hypermethylated in at least one of five gene promoters in 17/36 patients and in 3/22 controls (47.22% vs. 13.64%, respectively, p = 0.009). RASSF1 was hypermethylated in 10/17 (58.82%) specimens with detected methylation, APC in 7/17 (41.18%), DAPK in 4/17 (23.53%), RAR-β2 in 3/17 (17.56%) and TERT in none. According to a multivariate logistic regression analysis, NLUTD and male gender were significantly associated with hypermethylation (OR = 7.43, p = 0.007 and OR = 4.21; p = 0.04, respectively). In the tissue specimens, histology revealed TaLG BCa in two patients and urothelial squamous metaplasia in five patients. Chronic bladder inflammation was present in 35/41 bladder biopsies. Conclusions: DNA hypermethylation in a panel of five BCa-associated genes in the urine was significantly more frequent in NLUTD patients than in the controls. Our results warrant further evaluation in longitudinal studies assessing the clinical implications and possible associations between DNA hypermethylation, chronic inflammation and BCa in the NLUTD population.

Single-cell RNA sequencing reveals the immune microenvironment and signaling networks in cystitis glandularis.

Cystitis glandularis (CG) is a rare chronic bladder hyperplastic disease that mainly manifests by recurrent frequent urination, dysuria and gross hematuria. The current lack of unified diagnosis and treatment criteria makes it essential to comprehensively describe the inflammatory immune environment in CG research. Here, we performed scRNA-sequencing in CG patients for the first time, in which four inflamed tissues as well as three surrounding normal bladder mucosa tissues were included. Specifically, we isolated 18,869 cells to conduct bioinformatic analysis and performed immunofluorescence experiments. Our genetic results demonstrate that CG does not have the classic chromosomal variation observed in bladder tumors, reveal the specific effects of TNF in KRT15 epithelial cells, and identify a new population of PIGR epithelial cells with high immunogenicity. In addition, we confirmed the activation difference of various kinds of T cells during chronic bladder inflammation and discovered a new group of CD27-Switch memory B cells expressing a variety of immunoglobulins. CG was regarded as a rare disease and its basic study is still weak.Our study reveals, for the first time, the different kinds of cell subgroups in CG and provides the necessary basis for the clinical treatment of cystitis glandularis. Besides, our study significantly advances the research on cystitis glandularis at the cellular level and provides a theoretical basis for the future treatment of cystitis glandularis.

Bladder Mucosal Cystitis Cystica Lesions Are Tertiary Lymphoid Tissues That Correlate With Recurrent Urinary Tract Infection Frequency in Postmenopausal Women.

We identify correlates and clinical outcomes of cystitis cystica, a poorly understood chronic inflammatory bladder change, in women with recurrent urinary tract infections. A retrospective, observational cohort of women with recurrent urinary tract infections who underwent cystoscopy (n=138) from 2015 to 2018 were identified using electronic medical records. Cystitis cystica status was abstracted from cystoscopy reports and correlations were identified by logistic regression. Urinary tract infection-free survival time associated with cystitis cystica was evaluated by Cox proportional hazards regression. Exact logistic regression was used to identify factors associated with changes to cystitis cystica lesions on repeat cystoscopy. Biopsies of cystitis cystica lesions were examined by routine histology and immunofluorescence. Fifty-three patients (38%) had cystitis cystica on cystoscopy. Cystitis cystica was associated with postmenopausal status (OR: 5.53, 95% CI: 1.39-37.21), pelvic floor myofascial pain (6.82, 1.78-45.04), having ≥4 urinary tract infections in the past year (2.28, 1.04-5.09), and a shorter time to next urinary tract infection (HR: 1.54, 95% CI: 1.01-2.35). Forty-two patients (82%) demonstrated improvement or resolution of lesions. Ten/11 (91%) biopsied cystitis cystica lesions were tertiary lymphoid tissue with germinal centers and resembled follicular cystitis. Cystitis cystica lesions were associated with postmenopausal status, pelvic floor myofascial pain, and number of urinary tract infections in the prior year and predicted worse recurrent urinary tract infection outcomes. Cystitis cystica lesions are tertiary lymphoid tissue/follicular cystitis that may improve or resolve over time with treatment. Identifying cystitis cystica in recurrent urinary tract infection patients may be useful in informing future urinary tract infection risk and tailoring appropriate treatment strategies.

Enterovesical Fistula Presenting with Gross Hematuria and Fecaluria after Pelvic Radiation Therapy and Transurethral Resection of Bladder Tumor: A Case Report and Literature Review

&lt;p&gt;本案例為一名75歲女性表現為肉眼可見的血尿兩天，過去病史有10年前子宮頸癌第四期接受過骨盆腔放射治療、高血壓及第2型糖尿病。病人到本院急診就醫後住院接受進一步檢查，住院後第2天膀胱鏡發現出血性膀胱炎，住院後第4天接受經尿道膀胱腫瘤切除術，病理報告顯示為膀胱急慢性發炎併出血。病人於手術後第四天出院。病人於手術後第10天出現下腹痛、肉眼可見的血尿及糞尿，安排腹部電腦斷層及腸胃道鋇劑攝影均顯示迴腸膀胱廔管。後續安排住院接受剖腹探查、廔管及迴腸切除術及膀胱修補術。病理報告顯示為迴腸憩室和潰瘍伴有急性和慢性發炎。病人於術後第7天併發膀胱出血及膀胱滲漏，經膀胱鏡清血塊及腹腔引流後，於術後第36天出院。本文討論腸道膀胱廔管的病態生理學、危險因子、常見症狀、診斷及治療、手術併發症處理等。此案例提醒基層醫師若病人有肉眼可見的血尿合併骨盆腔放射線治療的病史應鑑別診斷腸道膀胱廔管，需儘早安排腸胃道鋇劑攝影或腹部電腦斷層，以免延誤診斷時機。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;The patient was a 75-year-old woman who presented with gross hematuria for two days. Her medical history included cervical cancer, stage IV treated with pelvic radiation therapy (RT) 10 years ago, hypertension, and type 2 diabetes mellitus. The patient visited the emergency department of our hospital on May 29, 2016, and was hospitalized for further evaluation. Cystoscopy on the 2nd day after admission revealed hemorrhagic cystitis. Transurethral resection of bladder tumor (TURBT) was performed on the 4th day after admission. The pathology report revealed acute and chronic bladder inflammation and bleeding. The patient was discharged on the 8th day after admission. However, the patient developed lower abdominal pain, gross hematuria, and fecaluria on the 10th postoperative day. Abdominal computed tomography (CT) and gastrointestinal tract (GI) series were performed, all of which showed an ileum-vesical fistula. Exploratory laparotomy, resection of the fistula and ileum, and bladder repair, were performed on June 17, 2016, fifteen days after her first operation. The surgeries were successful and uneventful. Pathological examination revealed a diverticulum and ulcer with transmural mixed acute and chronic inflammation. Unfortunately, the patient developed intraperitoneal bladder perforation on the 7th postoperative day. After adequate abdominal drainage and cystoscopy-assisted blood clot evacuation, she was discharged from the hospital on the 36th postoperative day. This article discusses the pathophysiology of enterovesical fistula, risk factors, common symptoms, diagnosis and treatment, and the management of surgical complications. Clinicians should keep this clinical scenario in mind if the patient has gross hematuria combined with a history of pelvic RT. This combination of symptoms and history should suggest a differential diagnosis of enterovesical fistula and arrangement of GI series or abdominal CT should be performed as soon as possible to avoid delaying the diagnosis.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Experimental in vivo model to evaluate the impact of Cernitin™ on pain response on induced chronic bladder inflammation

Objective Inflammation of the urinary bladder may cause burdensome pain also called bladder pain syndrome (BPS). A limitation in understanding BPS pathophysiology is the lack of appropriate preclinical model. Previously published clinical and preclinical studies revealed positive impact of Cernitin™ on pain relief in chronic prostatitis. The objective of this study was to evaluate the effects of Cernitin™ on induced inflammation of the urinary bladder in rats. We also sought to identify biomarkers which might play a role in the management of BPS. Materials and methods Cystitis was induced by injection of cyclophosphamide (CYP) in female rats. Thereafter, animals were randomly divided into four treatment groups and two control groups. Evaluation of pain scores was assessed by von Frey assay. Expression of pain- and pro-inflammatory biomarkers was determined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. Results Treatments with Cernitin™ displayed significant anti-nociceptive effects on CYP-induced visceral pain (p < .01). In contrast, vehicle-treated animals showed high pain score even at the lowest force. Furthermore, results of ELISA showed that Cernitin™-treated animals had significantly reduced levels of COX-2 (T60, p < .01; GBX, p < .05) in bladder tissue homogenate. Immunohistochemical (IHC) staining of bladder tissues showed that Cernitin™-treated animals exhibited less CD45-positive cells, while massive CD45-positive cells infiltration was detected in vehicle-treated animals. IHC also revealed lower SP and PGD2 expression levels in Cernitin™-treated tissues. Conclusions Cernitin™ components reduced pain score and inflammatory marker COX-2. Our findings suggest a potential therapeutic role for Cernitin™ in the management of BPS.

Inhibition of hypoxia-inducible factor-prolyl hydroxylation protects from cyclophosphamide-induced bladder injury and urinary dysfunction.

Disruption of the blood-urine barrier can result in acute or chronic inflammatory bladder injury. Activation of the oxygen-regulated hypoxia-inducible factor (HIF) pathway has been shown to protect mucosal membranes by increasing the expression of cytoprotective genes and by suppressing inflammation. The activity of HIF is controlled by prolyl hydroxylase domain (PHD) dioxygenases, which have been exploited as therapeutic targets for the treatment of anemia of chronic kidney disease. Here, we established a mouse model of acute cyclophosphamide (CYP)-induced blood-urine barrier disruption associated with inflammation and severe urinary dysfunction to investigate the HIF-PHD axis in inflammatory bladder injury. We found that systemic administration of dimethyloxalylglycine or molidustat, two small-molecule inhibitors of HIF-prolyl hydroxylases, profoundly mitigated CYP-induced bladder injury and inflammation as assessed by morphological analysis of transmural edema and urothelial integrity and by measuring tissue cytokine expression. Void spot analysis to examine bladder function quantitatively demonstrated that HIF-prolyl hydroxylase inhibitor administration normalized micturition patterns and protected against CYP-induced alteration of urinary frequency and micturition patterns. Our study highlights the therapeutic potential of HIF-activating small-molecule compounds for the prevention or therapy of bladder injury and urinary dysfunction due to blood-urine barrier disruption.NEW & NOTEWORTHY Disruption of the blood-urine barrier can result in acute or chronic inflammatory bladder injury. Here, we demonstrate that pharmacological inhibition of hypoxia-inducible factor (HIF)-prolyl hydroxylation prevented bladder injury and protected from urinary dysfunction in a mouse model of cyclophosphamide-induced disruption of the blood-urine barrier. Our study highlights a potential role for HIF-activating small-molecule compounds in the prevention or therapy of bladder injury and urinary dysfunction and provides a rationale for future clinical studies.

Inflammation and Barrier Function Deficits in the Bladder Urothelium of Patients with Chronic Spinal Cord Injury and Recurrent Urinary Tract Infections.

Patients with spinal cord injury (SCI) commonly experience neurogenic voiding dysfunctions and urinary tract complications, including recurrent urinary tract infections (rUTI). The bladder mucosa barrier function contributes to UTI prevention. This study investigated changes in bladder urothelium protein expression in patients with SCI and rUTI. From June 2011 to November 2017, 23 patients (19 men and 4 women) with chronic SCI were enrolled (mean age: 43 years. Bladder tissues from 6 healthy adults served as the normal control group. Biopsy samples (9 partial cystectomies and 14 bladder biopsies) were analyzed for functional biomarkers using western blot and immunohistochemistry analysis. The barrier function proteins E-cadherin, zonula occludens 1 (ZO-1) and uroplakin III (UPK-3) were significantly reduced, whereas tumor protein p63 (TP63) was significantly increased in SCI patients compared with controls. No significant differences in basal cell progenitor proteins were observed between groups. The proliferation marker Ki-67, the proapoptotic marker BCL-2-associated X protein (BAX), and proinflammatory proteins were increased in patients with SCI compared with controls. No significant differences were observed between SCI patients with and without recently rUTI. These results suggest that SCI patients experience chronic bladder inflammation, increased apoptosis, and reduced barrier function, contributing to rUTI.

Efficacy of intravesical cocktail therapy with or without dimethyl sulphoxide in interstitial cystitis.

Interstitial cystitis (IC) is a chronic bladder inflammation with unknown etiologies that impairs the quality of life of patients. We aimed to investigate the efficacy of dimethyl sulphoxide (DMSO) use in the cocktail therapy in IC patients. Patients treated with intravesical cocktail therapy which contained a mixture of 10 mL of bupivacaine, 1 mL of heparin, and 9 mL of sodium bicarbonate, was introduced to Group 1, and, 25 mL of DMSO was added to this cocktail and introduced to Group 2. Statistical analyses between groups were assessed by Turkish validated O'Leary Sant score composed of IC Symptom Index (ICSI) and IC Problem Index (ICPI), visual analog scale (VAS) score, and short form-36 (SF-36) questionnaire in the baseline versus post-instillation week 6, month 6, and month 12, comparatively. A total of 62 patients (58 women and 4 men) with a median age of 52 (28-76) years were included. Baseline versus post-instillation 6th week of ICSI and ICPI scores were 15 ±3.4 vs 7.4 ±2.9 and 12.6 ±2.8 vs 6.1 ±2.7, respectively (p <0.001 and <0.001, respectively). VAS scores of Group 2 were statistically significantly lower than that of Group 1 in the post-instillation month 6 (p = 0.03) whereas, the baseline of VAS scores were similar. Intravesical cocktail therapy is an effective and reliable treatment method and can be safely applied with or without DMSO. Adding DMSO to cocktail therapy provides a further decrease in VAS score in the post-instillation month 6.

Molecular pathways underlying tissue injuries in the bladder with ketamine cystitis.

Ketamine cystitis (KC) is a chronic bladder inflammation leading to urinary urgency, frequency, and pain. The pathogenesis of KC is complicated and involves multiple tissue injuries in the bladder. Recent studies indicated that urothelium disruption, lamina propria fibrosis and inflammation, microvascular injury, neuropathological alterations, and bladder smooth muscle (BSM) abnormalities all contribute to the pathogenesis of KC. Ketamine has been shown to induce these tissue injuries by regulating different signaling pathways. Ketamine can stimulate antiproliferative factor, adenosine triphosphate, and oxidative stress to disrupt urothelium. Lamina propria fibrosis and inflammation are associated with the activation of cyclooxygenase-2, nitric oxide synthase, immunoglobulin E, and transforming growth factor β1. Ketamine contributes to microvascular injury via the N-methyl-D aspartic receptor (NMDAR), and multiple inflammatory and angiogenic factors such as tumor necrosis factor α and vascular endothelial growth factor. For BSM abnormalities, ketamine can depress the protein kinase B, extracellular signal-regulated kinase, Cav1.2, and muscarinic receptor signaling. Elevated purinergic signaling also plays a role in BSM abnormalities. In addition, ketamine affects neuropathological alterations in the bladder by regulating NMDAR- and brain-derived neurotrophic factor-dependent signaling. Inflammatory cells also contribute to neuropathological changes via the secretion of chemical mediators. Clarifying the role and function of these signaling underlying tissue injuries in the bladder with KC can contribute to a better understanding of the pathophysiology of this disease and to the design of effective treatments for KC.

Suppression of adenosine A2a receptors alleviates bladder overactivity and hyperalgesia in cyclophosphamide-induced cystitis by inhibiting TRPV1

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a type of chronic bladder inflammation characterized by increased voiding frequency, urgency and pelvic pain. The sensitization of bladder afferents is widely regarded as one of the pathophysiological changes in the development of IC/BPS. There is evidence that adenosine A2a receptors are involved in regulating the sensitization of sensory afferents. However, the effect of adenosine A2a receptors on cystitis remains unknown. In the present study, a rat model of chronic cystitis was established by intraperitoneal injection with cyclophosphamide (CYP). Cystometry and behavioral tests were performed to investigate bladder micturition function and nociceptive pain. The rats with chronic cystitis showed symptoms of bladder overactivity, characterized by an increase in bladder voiding frequency and voiding pressure. CYP treatment significantly increased the expression of the A2a receptor in bladder afferent fibers and dorsal root ganglion (DRG) neurons. The A2a receptor antagonist ZM241385 prevented bladder overactivity and hyperalgesia elicited by CYP-induced cystitis. In addition, the A2a receptor and TRPV1 were coexpressed on DRG neurons. The TRPV1 antagonist capsazepine blocked bladder overactivity induced by the A2a receptor agonist CGS21680. In contrast, ZM241385 significantly inhibited the capsaicin-induced increase in intracellular calcium concentration in DRG neurons. These results suggest that suppression of adenosine A2a receptors in bladder afferents alleviates bladder overactivity and hyperalgesia elicited by CYP-induced cystitis in rats by inhibiting TRPV1, indicating that the adenosine A2a receptor in bladder afferents is a potential therapeutic target for the treatment of IC/BPS.

Inhibitory effect of gabapentin for interstitial cystitis/bladder pain syndrome in rats

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic bladder inflammation characterized by pelvic pain and urinary symptoms, such as urinary frequency and urgency. The etiology of IC/BPS is still not completely understood, and effective drug treatments have not been established. Therefore, the present study confirmed whether repeated intravesical injection of lipopolysaccharide (LPS) causes long-lasting painful and overactive bladder in rats. We further tested the effect of gabapentin on those symptoms in a rat model of LPS-induced chronic cystitis. In the histological examination, LPS-treated showed a greater inflammatory response, severe fibrosis and abnormally thick re-epithelialization. LPS revealed hyperalgesia in the region between the anus and urethral opening at 1day post-administration compared with controls, with no recovery over 21 days. In the cystometry, LPS-treated showed bladder hyperactivity at any times tested. Gabapentin showed significant analgesic effects, and significantly prevented the increased frequency of the voiding observed in the bladders of the LPS-treated. These results suggest that LPS-induced cystitis model shows long-lasting painful and overactive bladder in pathological condition, and gabapentin is effective on both symptoms in this chronic cystitis model.

Pathophysiology of refractory overactive bladder.

Overactive bladder (OAB) is a common condition. The International Continence Society defines OAB as a symptom complex characterized by urgency with or without urge incontinence, usually with frequency and nocturia. The first-line treatment for OAB includes behavioral therapy, such as caffeine reduction, fluid intake modification, weight reduction, bladder training, and pelvic floor muscle training, as well as treatment with antimuscarinic or β3 -adrenoceptor agonist medications. However, less than half of all cases achieve satisfactory outcomes following first-line treatment. Second-line therapy considered if satisfactory responses are not achieved after 8 to 12 weeks treatment with first-line therapy include intradetrusor botulinum toxin injection, neuromodulation, and surgical treatment. Patients with refractory OAB may have more severe symptoms or underlying pathophysiologies that were not resolved by the initial medication. The pathophysiologies of refractory OAB include occult neurogenic bladder, undetected bladder outlet obstruction, urethral-related OAB, urothelial dysfunction with aging, chronic bladder ischemia, chronic bladder inflammation, central sensitization, and autonomic dysfunction. This article discusses the possible pathophysiologies of refractory OAB.

Molecular pathogenesis of interstitial cystitis/bladder pain syndrome based on gene expression.

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic bladder inflammation that leads to chronic bladder pain and urinary urgency and frequency. The presentation of IC/PBS is heterogeneous, and it is classified as ulcerative IC/PBS and nonulcerative IC/PBS. The main cause of IC/PBS is thought to be a persistent inflammatory condition in the bladder, though the actual pathophysiology has not been identified yet. Although the underlying pathophysiology of IC/PBS is not completely understood, several theories for the etiology of this syndrome have been suggested, including deficiency of the glycosaminoglycan covering urothelium surface that results in leaky urothelium infection, immunological etiology, activated mast cells, neural changes, and inflammation. In addition, there are no gold standards for the detection of this disorder to date. So, determination of gene expression and its role in different signaling pathways in the pathogenesis of this heterogeneous disorder contribute to the more efficient cognition of the pathophysiology of this disease and to the design of effective treatments and molecular diagnostic methods for IC/PBS.

Downregulation of tight junction protein zonula occludens-2 and urothelium damage in a cyclophosphamide-induced mouse model of cystitis

ObjectivesThe cyclophosphamide (CYP)-induced model of cystitis in mice closely fits the symptoms of chronic bladder inflammation. Cystitis was recently found to be due to an altered gap junction protein in a rat model. Thus, this study was conducted to evaluate changes in protein expression and composition in the bladder of CYP-treated mice. Materials and methodsAdministration of CYP induced cystitis-related symptoms in mice. Cystometry was assessed and cell junction-associated protein zonula occludens-2 (ZO-2) expression was measured. Voiding interval values (time between voids) were assessed in mice under anesthesia. The bladders were removed for proteomic analysis using label-free quantitative proteomics and liquid chromatography–mass spectrometry. Additionally, immunochemistry (IHC) and Western blot were used to confirm the location and level, respectively, of ZO-2 expression. ResultsCompared to the control group, the voiding interval values and urothelial thickness in the bladder in the CYP-treated group were significantly decreased. Additionally, we identified 105 differentially expressed proteins in the bladder of CYP-treated mice with proteomic analysis. These proteins were involved in cell–cell tight junctions, exocytosis, muscle development, contraction, and regulation, immune responses, proteolysis, and cell adhesion. IHC and Western blot confirmed the downregulation of the tight junction protein ZO-2 in the urothelium of bladder. ConclusionsOur results suggest that downregulation in tight junction protein ZO-2 and urothelium damage may have a role in cystitis-related OAB. These changes could be related to the molecular mechanism of cystitis-related OAB.

Urinary Platelet‐Activating Factor as an Indicator of Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory bladder disease with multiple etiological contributors and risk factors associated with its development, including cigarette smoking. In a recently published manuscript, we have shown that smoking is associated with bladder wall inflammation and accumulation of platelet activating factor (PAF), a potent inflammatory mediator that facilitates transendothelial inflammatory cell migration and reduction in tight junction protein expression, which could contribute to urothelial cell dysfunction. PAF accumulation in response to cigarette smoking is primarily the result of the inhibition of PAF acetylhydrolase (PAF‐AH, the enzyme responsible for PAF hydrolysis and inactivation). The present study was designed to determine whether urine content of PAF or PAF‐AH activity can be used as an indicator of IC/BPS. For stability studies, voided urine specimens were collected from patients with and without a diagnosis of IC/BPS. Samples were stored at room temperature and frozen in liquid nitrogen at intervals up to 60 mins following voiding. PAF content and PAF‐AH activity were measured and normalized to creatinine. Measurement of PAF and PAF‐AH was consistent at all time intervals up to 60 mins, demonstrating stability following voiding. Addition of PAF internal standard to urine samples prior to analysis indicated a recovery of &gt;96% PAF. PAF content in the urine of IC/BPS patients (1.16 ± 0.16 PAF:creatinine ratio, n=6, p&lt;0.05) was significantly greater than that for non‐IC/BPS patients (0.37 ± 0.18 PAF:creatinine ratio, n=5). PAF content was also greater in IC/BPS patients who smoke (1.19 + 0.36 PAF:creatinine ratio, n=4, p&lt;0.05) when compared to non‐IC/BPS patients. PAF‐AH activity was decreased in the urine of IC/BPS patients who were smokers (48.3 ± 2.4 PAF‐AH: creatinine ratio, n=4, p&lt;0.05) or non‐smokers (40.0 ± 7.0 PAF‐AH: creatinine ratio, n=6, p&lt;0.05) when compared to non‐smokers with no IC/BPS (64.6 ± 2.2 PAF‐AH:creatinine ratio, n=5). Our data demonstrate that urine content of PAF and/or PAF‐AH is stable at up to 60 mins storage at room temperature following voiding. Urinary PAF is increased in IC/BPS patients, and is likely the result of PAF‐AH inhibition. Future studies are required to determine the effect of cigarette smoking on the incidence and severity of IC/BPS.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Pathophysiological Role of Transient Receptor Potential Ankyrin 1 in a Mouse Long-Lasting Cystitis Model Induced by an Intravesical Injection of Hydrogen Peroxide.

Chronic inflammatory bladder disorders, such as interstitial cystitis/bladder pain syndrome, are associated with poor quality of life. The exact pathological processes remain unclear, but accumulating evidence suggests that reactive oxidative species (ROS) are involved in urinary bladder disorders. Transient receptor potential ankyrin 1 (TRPA1), the most sensitive TRP channel to ROS, was shown to be responsible for urinary bladder abnormalities and hyperalgesia in an acute cystitis model. However, the roles of TRPA1 in chronic inflammatory bladder are not fully understood. We previously established a novel mouse cystitis model induced by intravesical injection of hydrogen peroxide (H2O2), resulting in long-lasting frequent urination, bladder inflammation, pain-related behavior, and histopathological changes. In the present study, we investigated the pathophysiological role of TRPA1 in the H2O2-induced long-lasting cystitis mouse model. Under anesthesia, 1.5% H2O2 solution was introduced transurethrally into the bladder of female wild-type (WT) and TRPA1-knockout mice and maintained for 30 min. This increased the number of voids in WT mice at 1 and 7 days after injection, but reduced the number in TRPA1-knockout mice at 1 day but not 7 days after injection. Spontaneous locomotor activities (increase in freezing time and decrease in distance moved) were reduced at 3 h after injection in WT mice, whereas the spontaneous visceral pain-related behaviors were attenuated in TRPA1-knockout mice. Furthermore, upregulation of c-fos mRNA in the spinal cord at 1 day after injection was observed in WT but not TRPA1-knockout mice. However, there was no difference in histopathological changes in the urinary bladder, such as edematous thickening in the submucosa, between WT and TRPA1-knockout mice at 1 or 7 days after injection. Finally, Trpa1 mRNA levels in the L5-S1 dorsal root ganglion were not altered, but levels in the urinary bladder were drastically increased at 1 and 7 days after injection. Taken together, these results suggest that TRPA1 contributes to acute bladder hyperactivity such as frequent urination and bladder pain, but does not appear to play a major role in the pathological processes of long-lasting cystitis.