Mast Cell Activation Triggers a Urothelial Inflammatory Response Mediated by Tumor Necrosis Factor-α

Current updates relating to treatment for interstitial cystitis/bladder pain syndrome: systematic review and network meta-analysis

BACKGROUND

Despite the publication of several meta-analyses regarding the efficacy of certain therapies in helping individuals with interstitial cystitis (IC) / bladder pain syndrome (BPS), these have not provided a comprehensive review of therapeutic strategies. The study aimed to determine the efficacy of various therapies for IC/BPS and identify potential moderating factors using randomized controlled trials (RCTs).

METHODS

We queried the PubMed, Cochrane, and Embase databases to identify prospective RCTs using inclusion criteria: 1) patients diagnosed with IC, 2) interventions included relevant treatments, 3) comparisons were a specified control or placebo, 4) outcomes were mean differences for individual symptoms and structured questionnaires. The pairwise meta-analysis and network meta-analysis (NMA) were performed to compare the treatments used in IC/BPS. Hedges' g standardized mean differences (SMDs) were used for improvement in all outcomes using random-effects models. Efficacy outcomes included individual symptoms such as pain, frequency, urgency, and nocturia, as well as structured questionnaires measuring IC/BPS symptoms.

RESULTS

A comprehensive literature search was conducted which identified 70 RCTs with 3,651 patients. The analysis revealed that certain treatments, such as instillation and intravesical injection, showed statistically significant improvements in pain and urgency compared to control or placebo groups in traditional pairwise meta-analysis. However, no specific treatment demonstrated significant improvement in all outcomes measured in the NMA. The results of moderator analyses to explore influential variables indicated that increasing age was associated with increased nocturia, while longer follow-up periods were associated with decreased frequency.

CONCLUSION

This systematic review and meta-analysis provide insights into the efficacy of various treatments for IC. Current research suggests that a combination of therapies may have a positive clinical outcome for patients with IC, despite the fact that treatment for this condition is not straightforward.

TRIAL REGISTRATION

PROSPERO CRD42022384024.

Bioenergetic profiles of peripheral mononuclear cells and systemic inflammation in women with Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS)

Inflammation is thought to contribute to the etiology of interstitial cystitis/bladder pain syndrome (IC/BPS). It is well-known that disruption in metabolism in immune cells contributes to inflammation in several inflammatory diseases. The purpose of this study was to investigate whether cellular bioenergetics is altered in monocytes and lymphocytes from women with IC/BPS, and if these alterations correlate with systemic inflammatory markers. Age and BMI matched adult healthy women (HS; n = 18) and women with IC/BPS (n = 18) were included in the study. Blood was collected to assess cellular bioenergetics in monocytes and lymphocytes using a Seahorse XF96 Analyzer and plasma cytokine levels were measured using Meso Scale Discovery immunoassays. The correlation between bioenergetic parameters, cytokines, and demographics was determined using Pearson correlation coefficients. Means of the two groups were compared using the two-group t-test. Patients with IC/BPS had reduced monocyte oxygen consumption rates and glycolytic rates compared to healthy subjects. In contrast, lymphocytes from these patients had increased oxygen consumption rates and glycolytic rates. Several cytokines and chemokines including Interferon-gamma (IFN-ɣ), tumor necrosis factor alpha (TNF-ɑ), Interleukin-6 (IL-6), Interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) levels were significantly elevated in the plasma of patients with IC/BPS. However, Transforming growth factor (TGF-β) and Interleukin-10 (IL-10) levels were significantly decreased in IC/BPS patients compared to HS. In addition, Interferon gamma (IFN-ɣ), TNF-ɑ, IL-8, and TGF-β levels correlated with several bioenergetic parameters in monocytes or lymphocytes from healthy subjects. In contrast, TNF-ɑ and IL-8 correlated with bioenergetic parameters in monocytes from IC/BPS patients. Monocyte and lymphocyte cellular bioenergetics and plasma cytokine levels are different in patients with IC/PBS compared to HS. It appears that systemic inflammation is greater in this cohort which may negatively impact immune cell function. The relationship between cellular bioenergetics and inflammation in monocytes and lymphocytes could be important in understanding the pathogenesis of IC/PBS and warrants further investigation.

Can montelukast sodium be an alternative treatment in the treatment of interstitial cystitis?

Background

The leukotriene D4 receptors have been detected in human bladder detrusor myocytes, and they can play the role of interstitial cystitis etiology.

Aim

Our study aims to explain the role of mast cells histologically and immunohistochemically in the pathogenesis and the effectiveness of montelukast that leukotriene D4 receptor antagonist in the treatment of interstitial cystitis.

Subjects and Methods

Twenty-four Wistar albino adult female rats were used. Group 1 (n = 8): control (sham) group, Group 2 (n = 8): interstitial cystitis group, and Group 3 (n = 8): treatment group. Groups 2 and 3 rats were administered 75 mg/kg cyclophosphamide four times every three days intraperitoneally. The rats in the treatment group were started on montelukast sodium as 10 mg/kg, 1 × 1/day per orally after the last administration of cyclophosphamide and were given for 14 days. Mast cells in the bladder tissues were examined histologically, and the presence of IL-6, 8, VEGF, and TNF alpha was examined immunohistochemically.

Results

Thin transitional epithelium, loose connective tissue, weak smooth muscle bundles, and signs of chronic inflammation were observed in the interstitial cystitis group. Regenerated transitional epithelium, intact basement membrane, compact lamina propia, thick smooth muscle bundles, and rare inflammatory cells were observed after the treatment with the montelukast. Mast cells were decreased in bladder tissue after treatment. IL-6, IL-8, VEGF, and TNF alpha levels were significantly decreased after treatment.

Conclusions

We found that inflammatory mediators were significantly reduced after treatment with montelukast in the interstitial cystitis group. Montelukast can be used as an effective drug in the treatment of interstitial cystitis.

Comprehensive transcriptome profiling of urothelial cells following TNFα stimulation in an in vitro interstitial cystitis/bladder pain syndrome model

Urothelial cells of the urinary bladder play a critical role in the development and progression of interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic and debilitating inflammatory disease. Given the lack of data on the exact phenotype and function of urothelial cells in an inflammatory setting (as in IC/BPS), we performed the first in-depth characterization of these cells using RNA sequencing, qPCR, ELISA, Western blot, and immunofluorescence. After TNFα stimulation, urothelial cells in the in vitro model of IC/BPS showed marked upregulation of several proinflammatory mediators, such as SAA, C3, IFNGR1, IL1α, IL1β, IL8, IL23A, IL32, CXCL1, CXCL5, CXCL10, CXCL11, TNFAIPR, TNFRSF1B, and BIRC3, involved in processes and pathways of innate immunity, including granulocyte migration and chemotaxis, inflammatory response, and complement activation, as well as TLR-, NOD-like receptor- and NFkB-signaling pathways, suggesting their active role in shaping the local immune response of the bladder. Our study demonstrates that the TNFα-stimulated urothelial cells recapitulate key observations found in the bladders of patients with IC/BPS, underpinning their utility as a suitable in vitro model for understanding IC/BPS mechanisms and confirming the role of TNFα signaling as an important component of the associated pathology. The present study also identifies novel upregulated gene targets of TNFα in urothelial cells, including genes encoding the acute phase protein SAA, complement component C3, and the cytokine receptor IFNGR1, which could be exploited as therapeutic targets of IC/BPS. Altogether, our study provides a reference database of the phenotype of urothelial cells in an inflammatory environment that will not only increase our knowledge of their role in IC/BPS, but also advance our understanding of how urothelial cells shape tissue immunity in the bladder.

Monoclonal Antibody Therapy for the Treatment of Interstitial Cystitis

An emerging theory regarding the potentially autoimmune nature of painful bladder syndrome/interstitial cystitis (PBS/IC) had led to several studies being conducted to assess the possible therapeutic effect of immunotherapeutic options for PBS/IC. This review presents the available evidence regarding the potential autoimmunity-based pathogenesis of PBS/IC and focuses on a main representative of the immunotherapeutic modalities for PBS/IC, aiming to summarize, evaluate, and present available data regarding the potential therapeutic role of monoclonal antibodies for PBS/IC patients. A non-systematic narrative and interpretative literature review was performed. The monoclonal antibodies included in the review were the anti-tumor necrosis factor-α (anti-TNF-α) agents adalimumab, which showed no difference compared to placebo, and certolizumab pegol, which showed statistically important differences in all outcome measures compared to placebo at the 18-week follow-up visit. Anti-nerve growth factor (anti-NGF) agents were also reviewed, including tanezumab, which showed both positive and negative efficacy results compared to placebo, and fulranumab, the study of which was discontinued owing to adverse events. In summary, monoclonal antibody therapy remains to be further researched in order for it to be proposed as a promising future treatment option for PBS/IC.

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.

Hyaluronic acid and chondroitin sulfate, alone or in combination, efficiently counteract induced bladder cell damage and inflammation

Interstitial cystitis and/or bladder pain syndrome (IC/BPS) are characterized by discomfort, abdominal pain, and pelvic pain, and they are often associated with chronic diseases. Pathological conditions related to IC/BPS can occur due to a defect in the integrity of the bladder lining. This defect has been ascribed to damage to the glycosaminoglycan (GAG) layer of the urinary epithelium. In addition, the incipient cascade of inflammation events might prompt extracellular matrix degradation. Several medical devices based on GAG instillation were proposed to re-establish epithelial integrity by GAGs binding to proteoglycans or interacting with structural urothelium. However, to date, only in vitro studies have investigated the GAG, hyaluronic acid (HA). In the present study, TNFα treatment was used to mimic IC/BPS-induced damage in bladder cells in an in vitro model. Highly purified fermentative HA and pharmaceutical grade bovine chondroitin sulfate (CSb), alone or in combination, were evaluated for the ability to counteract bladder cell damage. We evaluated NF-κB with western blots, and we analyzed interleukin 6 and 8 expression at the transcriptional and protein levels with quantitative RT-PCR, western blotting, and ELISA. We also evaluated the expression of an antibacterial peptide, human β-defensin-2. We confirmed our results in a 3D bladder epithelium model. Our results demonstrated that inflammatory status was reduced in the presence of HA, CSb, and the combination of both (HA/CSb 1.6%/2% w/v). This result suggested that these GAGs might be suitable for treating IC/BPS. All the assayed biomarkers showed that HA/CSb treatment modulated cells towards a more physiological status. Finally, we compared two commercial products suggested for the IC/BPS treatments and found that the product with more Ca++, showed enhanced anti-inflammatory activity and provided superior mucoadhesivity.

A Randomized, Double-blind, Placebo-controlled Trial of Certolizumab Pegol in Women with Refractory Interstitial Cystitis/Bladder Pain Syndrome

BACKGROUND

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic, disabling bladder disease, with an uncertain pathophysiology and no universally effective treatment.

OBJECTIVE

To evaluate the efficacy and safety of certolizumab pegol compared with placebo in women with refractory IC/BPS.

DESIGN, SETTING, AND PARTICIPANTS

Eligible women, aged 18-65 yr with moderate to severe IC/BPS, were enrolled in this randomized, double-blind, placebo-controlled pilot study.

INTERVENTION

Study patients were randomized at a 2:1 ratio to receive either certolizumab pegol or placebo.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome measure was a patient-reported global response assessment (GRA). Secondary endpoints included Interstitial Cystitis Symptom Index (ICSI), Interstitial Cystitis Problem Index (ICPI), and a numeric rating scale for pain and urgency.

RESULTS AND LIMITATIONS

The primary endpoint of GRA improvement at week 2 was not met. However, by week 18, there was significant improvement in GRA for certolizumab pegol compared with placebo in pain (odds ratio [OR]=17.3, p=0.002), urgency (OR=9.92, p=0.02), and overall symptoms (OR=15.0, p=0.006). At week 18, there was a statistically significant improvement for certolizumab pegol compared with placebo in change from baseline for ICSI of -3.6 (95% confidence interval [CI]: -6.9 to -0.29, p=0.03), ICPI of -3.0 (95% CI: -6.1 to 0.12, p=0.042), pain scale of -2.0 (95% CI: -3.9 to -0.15, p=0.02), and urgency scale of -1.7 (95% CI: -3.5 to 0.06, p=0.03). There was a significant difference in greater than 30% reduction in pain from baseline comparing certolizumab pegol with placebo at week 18 (OR=13.0, p=0.02). Limitations include a larger, longer, multicenter trial is warranted with phenotypic categorization of patients.

CONCLUSIONS

Women with moderate to severe refractory IC/BPS were more likely to experience significant improvement in symptoms with certolizumab pegol compared with placebo therapy. Further investigation of certolizumab pegol for the treatment of IC/BPS is warranted with a larger, longer, multicenter, randomized, placebo-controlled trial.

PATIENT SUMMARY

Women with moderate to severe interstitial cystitis/bladder pain syndrome were helped with a medication used to treat autoimmune diseases.

A MAPP Network study: overexpression of tumor necrosis factor-α in mouse urothelium mimics interstitial cystitis

Interstitial cystitis/bladder pain syndrome is a chronic bladder condition associated with pain and voiding dysfunction that is often regarded as a neurogenic cystitis. Patient symptoms are correlated with the presence of urothelial lesions. We previously characterized a murine neurogenic cystitis model that recapitulates mast cell accumulation and urothelial lesions, and these events were dependent on TNF. To further explore the role of TNF in bladder inflammation and function, we generated a transgenic mouse model with chronic TNF overexpression in urothelium under the control of the uroplakin II (UPII) promoter. Transgenic mouse lines were maintained by backcross onto wild-type C57BL/6J mice and evaluated for pelvic tactile allodynia as a measure of visceral pain, urinary function, and urothelial lesions. TNF mRNA and protein were expressed at greater levels in bladders of UPII-TNF mice than in those of wild-type mice. UPII-TNF mice showed significantly increased urinary frequency and decreased void volume. UPII-TNF mice had increased urothelial apoptosis and loss of urothelial integrity consistent with urothelial lesions. Overexpression of TNF was also associated with pelvic tactile allodynia. Consistent with these findings, UPII-TNF mice exhibited increased bladder afferent activity in response to stretch ex vivo. In summary, UPII-TNF mice display significant pelvic pain, voiding dysfunction, urothelial lesions, and sensory input. Thus UPII-TNF mice are a model for characterizing mechanisms of interstitial cystitis symptoms and evaluating therapies.

Changes in mast cell infiltration: a possible mechanism in detrusor overactivity induced by visceral hypersensitivity

OBJECTIVE

To establish the detrusor overactivity (DO) model induced by visceral hypersensitivity (VH) and investigate the relationship between mast cell (MC) infiltration and DO.

MATERIALS AND METHODS

Sixty rats are divided into 4 groups randomly: Group 1:Baseline group; Group 2: DO group; Group 3: CON group; Group 4: VH group. The colorectal distension (CRD) and abdominal withdral reflex (AWR) scores are performed to evaluate VH. The cystometric investigation and histological test of MC infiltration are assessed.

RESULTS

The threshold pressure of CRD in the VH group is significantly lower than that in the CON group (P<0.001). At the distension pressure ≥20 mmHg, the AWR scores of the VH group are significantly higher than those of the CON group (10 mmHg: P=0.33; 20 mmHg: P=0.028; 40 mmHg: P<0.001; 60 mmHg: P<0.001; 80 mmHg: P<0.001). DO model is successfully established in the VH group (DO rate=100%). Compared with the CON group, the numbers of MC infiltration are significantly increased in the VH group, including submucosa of bladder (P<0.001), mucosa lamina propria/mesentery of small intestine (P<0.001), and mucosa lamina propria/mesentery of large intestine (P<0.001). Furthermore, more MC activation as well as degranulation are observed in the VH group.

CONCLUSIONS

It is indicated that DO model can be established in the VH rats. The MC infiltration may play an important role in DO induced by VH, and may be helpful to understand the mechanisms of DO in VH patients.

The severity of experimental autoimmune cystitis can be ameliorated by anti-CXCL10 Ab treatment

Background

Interstitial cystitis (IC), more recently called painful bladder syndrome (PBS) is a complex disease associated with chronic bladder inflammation that primarily affects women. Its symptoms include frequent urinary urgency accompanied by discomfort or pain in the bladder and lower abdomen. In the United States, eight million people, mostly women, have IC/PBS. New evidence that autoimmune mechanisms are important in the pathogenesis of IC/PBS triggered interest.

Methodology/Principal Findings

SWXJ mice immunized with a homogenate of similar mice’s urinary bladders develop an autoimmune phenotype comparable to clinical IC with functional and histological alterations confined to the urinary bladder. Using the murine model of experimental autoimmune cystitis (EAC), we found that serum levels of CXCR3 ligand and local T helper type 1 (Th1) cytokine are elevated. Also, IFN-γ-inducible protein10 (CXCL10) blockade attenuated overall cystitis severity scores; reversed the development of IC; decreased local production of CXCR3 and its ligands, IFN-γ, and tumor necrosis factor-α (TNF-α); and lowered systemic levels of CXCR3 ligands. Urinary bladder CD4⁺ T cells, mast cells, and neutrophils infiltrates were reduced following anti-CXCL10 antibody (Ab) treatment of mice. Anti-CXCL10 Ab treatment also reversed the upregulated level of CXCR3 ligand mRNA at urinary bladder sites. The decreased number and percentage of systemic CD4⁺ T cells in EAC mice returned to normal after anti-CXCL10 Ab treatment.

Conclusion/Significance

Taken together, our findings provide important new information about the mechanisms underlying EAC pathogenesis, which has symptoms similar to those of IC/PBS. CXCL10 has the potential for use in developing new therapy for IC/PBS.

Physiological relevance of LL-37 induced bladder inflammation and mast cells

PURPOSE

We established the physiological relevance of LL-37 induced bladder inflammation. We hypothesized that 1) human urinary LL-37 is increased in pediatric patients with spina bifida, 2) LL-37 induced inflammation occurs in our mouse model via urothelial binding and is dose dependent and 3) LL-37 induced inflammation involves mast cells.

MATERIALS AND METHODS

To test our first hypothesis, we obtained urine samples from 56 pediatric patients with spina bifida and 22 normal patients. LL-37 was measured by enzyme-linked immunosorbent assay. Our second hypothesis was tested in C57Bl/6 mice challenged with 7 LL-37 concentrations intravesically for 1 hour. At 24 hours tissues were examined histologically and myeloperoxidase assay was done to quantitate inflammation. In separate experiments fluorescent LL-37 was instilled and tissues were obtained immediately (time = 0) and at 24 hours (time = 24). To test our final hypothesis, we performed immunohistochemistry for mast cell tryptase and evaluated 5 high power fields per bladder to determine the mean number of mast cells per mm(2).

RESULTS

Urinary LL-37 was 89-fold higher in patients with spina bifida. Mouse LL-37 dose escalation experiments revealed increased inflammation at higher LL-37 concentrations. Fluorescent LL-37 demonstrated global urothelial binding at time = 0 but was not visible at time = 24. Immunohistochemistry for tryptase revealed mast cell infiltration in all tissue layers. At higher concentrations the LL-37 challenge led to significantly greater mast cell infiltration.

CONCLUSIONS

Urinary LL-37 was significantly increased in pediatric patients with spina bifida. To our knowledge we report for the first time that LL-37 can elicit profound, dose dependent bladder inflammation involving the urothelium. Finally, inflammation propagation involves mast cells.

BALB/c-Fcgr2bPdcd1 mouse expressing anti-urothelial antibody is a novel model of autoimmune cystitis

We report the impact of anti-urothelial autoantibody (AUAb) on urinary bladder phenotype in BALB/c mice deficient of the FcγRIIb and PD-1. AUAb was present in serum samples from approximately half of the double-knockout (DKO) mice, as detected by immunofluorescence and immunoblots for urothelial proteins including uroplakin IIIa. The AUAb-positive DKO mice showed degeneration of urothelial plaque and umbrella cells, along with infiltration of inflammatory cells in the suburothelial layer. TNFα and IL-1β were upregulated in the bladder and the urine of AUAb-positive DKO mice. Voiding behavior of mice was analyzed by the Voided Stain on Paper method. 10-week-old and older AUAb-positive DKO mice voided significantly less urine per void than did wild type (WT) mice. Furthermore, administration of the AUAb-containing serum to WT mice significantly reduced their urine volume per void. In summary, this report presents a novel comprehensive mouse model of autoimmune cystitis.

Role of inflammation in bladder function and interstitial cystitis

Cystitis, or inflammation of the bladder, has a direct effect on bladder function. Interstitial cystitis is a syndrome characterized by urinary bladder pain and irritative symptoms of more than 6 months duration. It commonly occurs in young to middle-aged women with no known cause and in fact represents a diagnosis of exclusion. Many factors have been suggested, including chronic or subclinical infection, autoimmunity and genetic susceptibility, which could be responsible for initiating the inflammatory response. However, a central role of inflammation has been confirmed in the pathogenesis of interstitial cystitis. Patients with interstitial cystitis are usually managed with multimodal therapy to break the vicious cycle of chronic inflammation at every step. Patients who develop irreversible pathologies such as fibrosis are managed surgically, which is usually reserved for refractory cases.

Tumor necrosis factor-α induces expression and release of interleukin-6 by human urothelial cells

OBJECTIVE

We examined the effects of tumor necrosis factor-α (TNF-α) on expression and release of interleukin-6 (IL-6) by human urothelial cells (HUCs) and investigated whether the effects of TNF-α are mediated by mitogen-activated protein kinase (MAPK) pathways.

MATERIALS AND METHODS

HUCs were treated with TNF-α at 1-10 ng/ml for 2-24 h. Expression of IL-6 and TNF-α receptor 1 (TNFR1) mRNAs were examined by real-time PCR. The release of IL-6 into culture medium was determined by ELISA. The presence of TNFR1 protein and TNF-α-induced activation of MAPK pathways was examined by immunoblotting analysis. The effects of selective blockers of MAPK pathways on TNF-α-induced IL-6 expression and release were determined.

RESULTS

TNF-α increased IL-6 mRNA expression and stimulated release of IL-6 in a concentration- and time-dependent manner. The effects of TNF-α were mediated by TNFR1. TNF-α induced phosphorylation of ERK1/2 and JNK, and TNF-α-induced IL-6 expression and release were inhibited by selective ERK1/2 and JNK blockers.

CONCLUSIONS

These results demonstrate that TNF-α increases expression and release of IL-6 by HUCs and that the effects of TNF-α are mediated by TNFR1. Also, the ERK1/2 and JNK pathways are involved in TNF-α-induced expression and release of IL-6 in HUCs and may represent therapeutic targets in inflammatory urinary tract diseases.

Intakes of vitamins and minerals in relation to urinary incontinence, voiding, and storage symptoms in women: a cross-sectional analysis from the Boston Area Community Health survey

BACKGROUND

Whether lower urinary tract symptoms (LUTS), including voiding, storage, and urinary incontinence, are affected by dietary micronutrients is uncertain.

OBJECTIVE

To test the hypothesis that carotenoid, vitamin C, zinc, and calcium intakes are associated with LUTS and urinary incontinence in women.

DESIGN, SETTING, AND PARTICIPANTS

During an observational, cross-sectional, population-based epidemiologic study of 2060 women (30-79 yr of age) in the Boston Area Community Health (BACH) survey (2002-2005), data were collected by validated food frequency questionnaire and in-person interviews and analyzed using multivariate regression.

MEASUREMENTS

LUTS, storage, and voiding symptoms were assessed using the American Urological Association Symptom Index (AUASI) and a validated severity index for urinary incontinence.

RESULTS AND LIMITATIONS

Women who consumed high-dose vitamin C from diet and supplements were more likely to report storage symptoms, especially combined frequency and urgency (≥ 500 vs < 50mg/d; odds ratio [OR]: 3.42; 95% confidence interval [CI], 1.44-8.12). However, greater consumption of dietary vitamin C or β-cryptoxanthin was inversely associated with voiding symptoms (p(trend) ≤ 0.01). Both dietary and supplemental calcium were positively associated with storage symptoms (eg, supplement ≥ 1000 mg/d vs none; OR: 2.04; 95% CI, 1.35-3.09; p(trend)=0.0002). No consistent associations were observed for β-carotene, lycopene, or other carotenoids, although smokers using β-carotene supplements were more likely to report storage problems. Whether the observed associations represent direct causes of diet on LUTS is uncertain.

CONCLUSIONS

High-dose intakes of vitamin C and calcium were positively associated with urinary storage or incontinence, whereas vitamin C and β-cryptoxanthin from foods and beverages were inversely associated with voiding symptoms. Results indicate that micronutrient intakes may contribute to LUTS in dose-dependent and symptom-specific ways. Further study is needed to confirm these findings and their relevance to clinical treatment decisions.

Urothelial cell platelet-activating factor production mediated by calcium-independent phospholipase A2γ

OBJECTIVES

To determine the effect of phospholipase A(2) (PLA(2)) inhibitors on urothelial cell platelet-activating factor (PAF) production in response to tryptase stimulation.

METHODS

Urothelial cells isolated from normal human ureters were immortalized with the human papillomavirus type 16E6E7 cell line (TEU-2 cells). PLA(2) activity in TEU-2 cells was measured using (16:0, [(3)H]18:1) plasmenylcholine and phosphatidylcholine substrates in the presence and absence of calcium. [(3)H]PAF production was measured in TEU-2 cells prelabeled with [(3)H] acetic acid. PAF-acetylhydrolase activity was measured by determining the amount of [(3)H] acetate hydrolyzed from [(3)H]PAF incubated with TEU-2 cellular protein. Adherence of human polymorphonuclear leukocyte (PMN) to TEU-2 cells was assessed by measuring myeloperoxidase activity in adherent PMNs after incubation with TEU-2 cells.

RESULTS

Most PLA(2) activity measured in TEU-2 cells was determined to be membrane-associated, calcium-independent PLA(2) and selective for plasmenylcholine substrate. Stimulation of TEU-2 cells with tryptase results in increased production of PAF and increased PMN adherence that were inhibited completely by pretreatment with the membrane-associated, calcium-independent PLA(2)γ-selective inhibitor (R)-bromoenol lactone. Pretreatment with the cytosolic PLA(2) inhibitor methyl arachidonyl fluorophosphonate resulted in potentiation of tryptase-stimulated PAF production and PMN adherence to TEU-2 cells that is a result of PAF-acetylhydrolase inhibition.

CONCLUSIONS

Tryptase stimulation of TEU-2 cells results in activation of membrane-associated, calcium-independent PLA(2)γ, leading to an increase in PAF production and increased PMN adherence. Inhibition of TEU-2 cell PAF-acetylhydrolase activity with methyl arachidonyl fluorophosphonate potentiated tryptase-stimulated PAF production and PMN adherence.

Endogenous nerve growth factor regulates collagen expression and bladder hypertrophy through Akt and MAPK pathways during cystitis

Type I collagen forms the main constituent of the extracellular matrix in visceral organs. We reported here that cyclophosphamide (CYP)-induced cystitis significantly increased the production of type I collagen in the inflamed bladder leading to increases in the bladder weight and the thickness of the bladder wall. The endogenous nerve growth factor (NGF) in the urinary bladder regulated type I collagen expression because the neutralizing NGF antibody attenuated cystitis-induced type I collagen up-regulation in the inflamed bladder. Neutralizing NGF antibody also subsequently reversed cystitis-induced increases in bladder weight. Further studies on the intermediate signaling pathways mediating NGF-induced type I collagen expression in the inflamed bladder during cystitis revealed that Akt, JNK, and ERK1/2 activities were increased in the inflamed bladder, whereas p38 MAPK remained unchanged. Suppression of endogenous NGF level with neutralizing NGF antibody significantly blocked the increased activity of Akt, JNK, and ERK1/2 in the inflamed bladder during cystitis. These results indicate that endogenous NGF plays an important role in the activation of Akt and MAPK in the urinary bladder and in bladder hypertrophy during cystitis.

Interstitial cystitis: bladder pain and beyond

BACKGROUND

Interstitial cystitis is characterized by over 6 months of chronic pain, pressure and discomfort felt in the lower pelvis or bladder. It is often relieved with voiding, along with daytime frequency and nocturia in the absence of a urinary tract infection. Interstitial cystitis occurs primarily in females including adolescents and its diagnosis is still one of exclusion. It is now recognized as a serious medical condition associated with significant disability.

OBJECTIVE

The aim of this paper was to review the pathogenesis and treatment of interstitial cystitis with emphasis on new pathogenetic trends and therapeutic modalities.

METHODS

About 713 mostly original papers were reviewed in Medline from 1990 to August. 2008. All authors independently reviewed the literature. Large, double-blind, placebo-controlled, clinical trials were few and the medical histories of the patients used varied considerably making conclusions difficult. Promising pilot trials turned out mostly negative on follow-up.

RESULTS

Increasing evidence of co-morbid diseases, neurogenic inflammation and the effect of stress are promising as new targets for pathophysiology. No new effective treatments have emerged. Oral pentosanpolysulfate, amitriptyline, hydroxyzine and quercetin, as well as intravesical heparin/bicarbonate/lidocaine solutions, are still used with variable success. Some pilot open-label trials presented encouraging findings.

CONCLUSION

Interstitial cystitis contributes substantially to chronic pelvic pain and to poor quality of life. Oral or intravesical administration of solutions containing sodium hyaluronate, chondroitin sulfate and quercetin to both reduce bladder inflammation and 'replenish' the glycosaminoglycan layer should be tried. There is a clear need for therapeutic modalities. New potential translational research areas are suggested.

CXCL10 blockade protects mice from cyclophosphamide-induced cystitis

Background

Alterations in serum CXCR3 ligand levels were examined in interstitial cystitis (IC) patients; similar expression patterns in serum as well as CXCR3, CXCR3 ligands, and cytokines expressed by peripheral and local leukocyte subpopulations were characterized during cyclophosphamide (CYP)-induced acute cystitis in mice.

Results

Serum levels of monokine-induced by interferon-γ (IFN-γ) (MIG/CXCL9), IFN-γ-inducible protein-10 (IP-10/CXCL10), and IFN-γ-inducible T cell α chemoattractant (I-TAC/CXCL11) were elevated in patients with IC. These clinical features closely correlated with CYP-induced cystitis in mice. Serum levels of these CXCR3 ligands and local T helper type 1 (Th1) cytokines were also increased. We demonstrate that CXCR3 as well as CXCL9, CXCL10 and CXCL11 mRNA were significantly expressed by urinary bladder lymphocytes, while CXCR3 and CXCL9 transcripts were significantly expressed by iliac lymph node leukocytes following CYP treatment. We also show that the number of CD4⁺ T cells, mast cells, natural killer (NK) cells, and NKT cells were increased at systemic (spleen) and mucosal (urinary bladder and iliac lymph nodes) sites, following CYP-induced cystitis in mice. Importantly, CXCL10 blockade attenuated these increases caused by CYP.

Conclusion

Antibody (Ab)-mediated inhibition of the most abundant serum CXCR3 ligand, CXCL10, in mice decreased the local production of CXCR3 ligands as well as Th1 cytokines expressed by local leukocytes, and lowered corresponding serum levels to reduce the severity of CYP-induced cystitis. The present study is among the first to demonstrate some of the cellular and molecular mechanisms of chemokines in cystitis and may represent new drug target for this disease.

Multiplex analysis of urinary cytokine levels in rat model of cyclophosphamide-induced cystitis

OBJECTIVES

The urinary proteome is a potential easily accessible source of biomarkers for inflammatory bladder diseases, including interstitial cystitis. In the present study, we subjected rat urine to multiplex cytokine analysis in an attempt to identify an inflammatory signature of the temporal course of cyclophosphamide (CYP)-induced cystitis.

METHODS

Rat urine was collected for 12 hours after CYP injection (150 mg/kg) for multiplex analysis of 14 cytokines by a multiple antigen bead assay (Luminex 100 IS). Urine from each void was collected, and the voiding frequency was determined. The bladder tissue was analyzed for cytokines levels and histologic evidence of inflammation.

RESULTS

Significant changes were noted in the urine levels of all cytokines with respect to baseline at 2, 4, 6, and 10 hours after CYP injection. Elevation was noted at all times for most cytokines, except for monocyte chemotactic protein-1, which had a 5-fold decrease at 2 hours. The urine and tissue levels of interleukin (IL)-1beta, IL-4, and growth-related oncogene/keratinocyte-derived chemokine correlated significantly, with a positive Spearman correlation also noted for granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein-1-1, IL-18, and interferon-gamma. The tissue levels for most cytokines, except for IL-2, and urinary frequency were significantly elevated in the CYP-treated rats compared with the control vehicle-treated rats. The hints of severe inflammation in the bladder indicated by the urinary cytokines were confirmed by bladder histologic examination and the tissue cytokine levels at necropsy.

CONCLUSIONS

The progression of CYP-induced cystitis was clearly reflected in the urine matrix by the temporal and quantitative changes in the cytokine levels. Additional delineation of urine and bladder tissue cytokine expression might yield biomarkers for cystitis.

RDP58 inhibits T cell-mediated bladder inflammation in an autoimmune cystitis model

Interstitial cystitis (IC) is a chronic inflammatory condition of the urinary bladder with a strong autoimmune component. Currently, the major challenge in IC treatment is the development of effective therapies. RDP58 is a novel d-amino acid decapeptide with potent immunosuppressive activity. In this study, we investigated whether RDP58 was effective as an intravesical agent for treating bladder autoimmune inflammation in a transgenic mouse model (URO-OVA mice). URO-OVA mice were adoptively transferred with syngeneic activated splenocytes of OT-I mice transgenic for the OVA-specific CD8(+) TCR for cystitis induction and treated intravesically with RDP58 at days 0 and 3. Compared with controls, the RDP58-treated bladders showed markedly reduced histopathology and expressions of mRNAs and proteins of TNF-alpha, NGF and substance P. To determine whether the inhibition of bladder inflammation by RDP58 was due to the interference with effector T cells, we treated the cells with RDP58 in vitro. Cells treated with RDP58 showed reduced production of TNF-alpha and IFN-gamma as well as apoptotic death. Collectively, these results indicate that RDP58 is effective for treating T cell-mediated experimental autoimmune cystitis and may serve as a useful intravesical agent for the treatment of autoimmune-associated bladder inflammation such as IC.

Urine markers do not predict biopsy findings or presence of bladder ulcers in interstitial cystitis/painful bladder syndrome

PURPOSE

We tested for associations between urine markers, bladder biopsy features and bladder ulcers in interstitial cystitis/painful bladder syndrome.

MATERIALS AND METHODS

Subjects were 72 patients with interstitial cystitis/painful bladder syndrome undergoing bladder distention and biopsy. Urine was collected before the procedure. Urine marker levels were correlated with biopsy and cystoscopic findings. Patients with no previous interstitial cystitis/painful bladder syndrome treatments (47) were analyzed separately from previously treated patients (25).

RESULTS

For untreated patients urine interleukin-6 and cyclic guanosine monophosphate were associated with urothelial epidermal growth factor receptor staining (for interleukin-6 r = 0.29; 95% CI 0.07, 0.51; p = 0.01 and for cyclic guanosine monophosphate r = 0.34; 95% CI 0.13, 0.55; p = 0.002). Urine interleukin-8 was negatively associated with urothelial heparin-binding epidermal growth factor-like growth factor staining (r = -0.34; 95% CI -0.55, -0.12; p = 0.002) and positively associated with lamina propria mast cell count (r = 0.29; 95% CI 0.06, 0.52; p = 0.01). The latter association also was seen in treated patients (r = 0.46; 95% CI 0.20, 0.73; p <0.001). None of the urine markers was significantly different for ulcer vs nonulcer groups. All of the patients with ulcer had extensive inflammation on bladder biopsy including severe mononuclear cell infiltration, moderate or strong interleukin-6 staining in the urothelium and lamina propria, and leukocyte common antigen staining in more than 10% of the lamina propria. However, these features also were seen in 24% to 76% of the patients without ulcer.

CONCLUSIONS

Overall urine markers did not associate robustly with biopsy findings. The strongest association was a positive association between urine interleukin-8 levels and bladder mast cell count. Patients with ulcer consistently had bladder inflammation but the cystoscopic finding of ulcers was not a sensitive indicator of inflammation on bladder biopsy.

Treatment approaches for painful bladder syndrome/interstitial cystitis

Painful bladder syndrome/interstitial cystitis (PBS/IC) is a disease of unknown aetiology, characterised by severe pressure and pain in the bladder area or lower pelvis that is frequently or typically relieved by voiding, along with urgency or frequency of urination in the absence of urinary tract infections. PBS/IC occurs primarily in women, is increasingly recognised in young adults, and may affect as many as 0.1-1% of adult women. PBS/IC is often comorbid with allergies, endometriosis, fibromyalgia, irritable bowel syndrome and panic syndrome, all of which are worsened by stress. As a result, patients may visit as many as five physicians, including family practitioners, internists, gynaecologists, urologists and pain specialists, leading to confusion and frustration. There is no curative treatment; intravesical dimethyl sulfoxide, as well as oral amitriptyline, pentosan polysulfate and hydroxyzine have variable results, with success more likely when these drugs are given together. Pilot clinical trials suggest that the flavonoid quercetin may be helpful. Lack of early diagnosis and treatment can affect outcomes and leads to the development of hyperalgesia/allodynia.

The Mast Cell in Interstitial Cystitis: Role in Pathophysiology and Pathogenesis

Current evidence from clinical and laboratory studies confirms that mast cells play a central role in the pathogenesis and pathophysiology of interstitial cystitis (IC). In this article, we focus on the role of the mast cell in IC and examine the ways in which mast cells and other pathophysiologic mechanisms are interrelated in this disease. Identifying the patients with IC who have mast cell proliferation and activation will enable us to address this aspect of disease pathophysiology in these individuals with targeted pharmacotherapy to inhibit mast cell activation and mediator release.

Intravesical Suplatast Tosilate (IPD-1151T) Inhibits Experimental Bladder Inflammation

PURPOSE

Interstitial cystitis is a painful bladder disease characterized by urgency, frequency and variable inflammation but there is no curative therapy. Suplatast tosilate (IPD-1151T) is an immunoregulatory compound that decreases interstitial cystitis symptoms but to our knowledge its mechanism of action is unknown. We investigated the effect of intravesical IPD-1151T on mediator release from bladder explants in experimental cystitis.

MATERIALS AND METHODS

A catheter was inserted into the bladder of female mice. After urine was emptied normal saline, carbachol (100 nM) or lipopolysaccharide (10 mg/ml) was introduced with or without 10-minute pretreatment with IPD-1151T. Urine was removed after 45 minutes for histamine and tumor necrosis factor-alpha assays. The bladder was removed after 4 hours, minced into 1 mm2 pieces and cultured with or without triggers overnight for mediator release. The effect of IPD-1151T was also tested on rat skin vascular permeability as well as on purified rat peritoneal mast cells and human cord blood derived mast cells.

RESULTS

Carbachol significantly increased histamine release in urine (61.3% in 8 preparations, p<0.05) but not in explant medium. IPD-1151T inhibited this effect by 77%. Lipopolysaccharide induced a 350% urine histamine increase in 9 preparations (p<0.05) and a 300% tumor necrosis factor-alpha increase in explant medium. IPD-1151T inhibited the lipopolysaccharide induced medium tumor necrosis factor-alpha increase by 95% in 5 preparations (p<0.05). IPD-1151T did not inhibit rat skin vascular permeability or purified rat peritoneal mast cell activation by compound 48/80 or human cord blood derived mast cells by anti-IgE.

CONCLUSIONS

IPD-1151T inhibits bladder release of histamine and tumor necrosis factor-alpha through a mechanism that does not appear to involve direct mast cell inhibition. These findings may justify a beneficial effect of IPD-1151T in interstitial cystitis.

Urothelial lesion formation is mediated by TNFR1 during neurogenic cystitis

Interstitial cystitis (IC) is a chronic bladder inflammatory disease of unknown etiology that shares similarities with Crohn's disease and psoriasis. IC, often regarded as a neurogenic cystitis, is associated with urothelial lesions that likely compromise the bladder permeability barrier and thereby contribute to patient morbidity. Here, we use a murine model of neurogenic cystitis to investigate the mechanism of urothelial lesion formation and find that urothelial apoptosis induces formation of lesions. Lesions formed in wild-type mice but not in mice deficient in TNF, TNF receptors, or mast cells. In urothelial cultures, only siRNAs targeting TNFR1, but not TNFR2, blocked TNF-induced apoptosis, indicating a primary role for TNFR1. Trans-epithelial resistance, a measure of bladder barrier function, decreased during neurogenic cystitis in wild-type and TNFR2(-/-) mice but was stabilized in TNF(-/-) mice. Anti-TNF antibodies both altered bladder mast cell localization and stabilized barrier function. Based on these findings, we conclude that mast cell activation and release of TNF drive urothelial apoptosis and lesion formation in a murine neurogenic cystitis model, and we hypothesize that anti-TNF therapy may stabilize bladder barrier function in IC patients.

Tumor necrosis factor promotes differential trafficking of bladder mast cells in neurogenic cystitis

PURPOSE

IC is often considered neurogenic cystitis, in which mast cells are involved in a positive feedback loop that results in sustained urothelial inflammation. To characterize these processes we developed a murine model of neurogenic cystitis using Bartha's strain of PRV based on a similar model in the rat.

MATERIALS AND METHODS

Female C57BL/6 mice (National Cancer Institute, Bethesda, Maryland) were used in the study. Neurogenic cystitis was induced by the injection of Bartha's strain of PRV (2.2 x 10 pfu) into the abductor caudalis dorsalis tail base muscle. Bladder inflammation was assessed by leukocyte influx and Evans blue dye extravasation. Mast cells were visualized in bladder tissue by staining with 0.1% toluidine blue.

RESULTS

Inoculation with PRV in the abductor caudalis dorsalis resulted in cystitis within 3 days. Coincident with the induction of cystitis mast cells accumulated in the lamina propria due to mast cell trafficking from the proximal detrusor (relative to the lumen), whereas mast cells from the distal detrusor were unchanged and total mast cell counts were not increased. Degranulated mast cells increased approximately 20-fold in the lamina propria of infected mice relative to controls. In TNF receptor 1/2 deficient mice (Jackson Laboratory, Bar Harbor, Maine) mast cell trafficking was not observed in response to PRV and mast cells were not degranulated.

CONCLUSIONS

These data indicate that neurogenic cystitis is associated with the differential trafficking and activation of distinct mast cell pools in the bladder. Since TNF mediates these events, anti-TNF therapy may mitigate the pathogenesis of neurogenic cystitis.

MODULATING BLADDER NEURO-INFLAMMATION: RDP58, A NOVEL ANTI-INFLAMMATORY PEPTIDE, DECREASES INFLAMMATION AND NERVE GROWTH FACTOR PRODUCTION IN EXPERIMENTAL CYSTITIS

PURPOSE

In interstitial cystitis (IC) inflammation induces and perpetuates neurotrophic changes in the bladder, resulting in the symptoms of frequency, urgency and pain. RDP58 (NH2-arg-norleucine (nle)-nle-arg-nle-nle-nle-gly-tyr-CONH2) (Sangstat Corp., Fremont, California) is a novel synthetic peptide that inhibits early signal transduction pathways for the expression of inflammatory cytokines. In this study we evaluated the effects of intravesical RDP58 on an established model of cystitis.

MATERIALS AND METHODS

Mice were catheterized and equal volumes of Escherichia coli lipopolysaccharide (LPS) or saline were instilled into the bladder. After 45 minutes the bladders were drained and distilled water or RDP58 (1 mg/ml) was instilled for 30 minutes. At 24 hours later the bladders were excised and cultured for analysis of tumor necrosis factor-alpha (TNF-alpha), substance P (SP) and nerve growth factor (NGF) production, as quantified by enzyme-linked immunosorbent assay.

RESULTS

LPS caused severe inflammation in mouse bladders compared with controls. Exposure to LPS increased the levels of TNF-alpha, SP and NGF production compared with controls (each p <0.05). In LPS exposed mice RDP58 significantly decreased inflammatory parameters by 82% 24 hours after treatment (p <0.05). Within 4 hours RDP58 abolished TNF-alpha production and at 24 hours TNF-alpha remained undetectable. RDP58 also significantly decreased SP and NGF production in LPS exposed bladders by more than 40% and 85%, respectively (each p <0.05).

CONCLUSIONS

Inflammatory models of cystitis result in increased levels of TNF-alpha, SP and NGF production in the bladder, paralleling the hypothesized neuro-inflammatory etiology of IC. RDP58 decreases inflammation and neurotrophic factors in vivo and it may potentially treat bladder disorders with an inflammatory component, such as IC.

Expression of intercellular adhesion molecules in the bladder of patients with interstitial cystitis

OBJECTIVES

To study the presence of intercellular adhesion molecule-1 (ICAM-1), P-selectin, and E-selectin, as well as the cytoskeletal components talin and vinculin that bind to cellular adhesion molecules (CAMs), in bladder biopsies from patients with interstitial cystitis (IC) and controls. IC is a sterile, bladder disorder characterized by urinary frequency and pelvic floor pain. The pathologic bladder findings include defective urothelium, activated mast cells, and variable inflammation. Mast cells can induce the expression of CAMs necessary for initiation of inflammation.

METHODS

Fresh frozen biopsies were analyzed immunocytochemically from 2 female normal bladders, 10 female IC bladders, 1 clear margin of transitional cell carcinoma of female bladder, 1 normal foreskin, 1 transitional cell carcinoma of foreskin, and 1 inflamed male finger.

RESULTS

Of the 10 IC samples, 9 were positive for ICAM-1, 6 for P-selectin, 6 for vinculin, 5 for talin, and 4 for E-selectin, all exclusively perivascular. Both normal bladders were negative for ICAM-1 and P-selectin and faintly positive for E-selectin, and one was weakly positive for talin and vinculin; the normal foreskin was negative. The "control" samples from the transitional cell carcinoma of the bladder and foreskin, as well as the inflamed finger skin, were positive only for ICAM-1. An increased number of activated mast cells associated with ICAM-1 was noted in IC.

CONCLUSIONS

These results showed that ICAM-1 is expressed in IC, with variable expression of the other markers studied, supporting the different degrees of bladder inflammation noted in patients with IC.

Permanent occlusion of the middle cerebral artery upregulates expression of cytokines and neuronal nitric oxide synthase in the spinal cord and urinary bladder in the adult rat

The expression pattern of proinflammatory cytokines, neuronal nitric oxide synthase (nNOS), substance P (SP) and calcitonin gene related peptide (CGRP) in the spinal cord and the bladder in response to permanent middle cerebral artery occlusion (MCAO) was investigated. In this connection, the gene expression of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1beta) and interleukin-6 in the lumbosacral spinal cord and the bladder as determined by real-time polymerase chain reaction was upregulated. In the spinal cord, the immunoreactivity of TNF-alpha and IL-1beta was mainly localized in the ventral horn motoneurons contralateral to MCAO. In the bladder, TNF-alpha was mainly expressed in the inflammatory cells. The expression of nNOS immunoreactivity as well as nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining in the spinal cord and bladder was also markedly increased in response to MCAO. Furthermore, the temporal and spatial expression of nNOS paralleled that of TNF-alpha and IL-1beta in the spinal cord. On the other hand, there was no noticeable change in gene expression and immunoreactivity of SP and CGRP. The present results have shown that cytokines and nNOS expression are elevated in areas far removed from the primary site of ischemic infarct, namely, the lumbosacral spinal cord and bladder. This together with some neuronal deaths maybe linked to the dysfunction of the latter in a clinical stroke. On the other hand, the apparent lack of SP and CGRP changes following MCAO suggests that the two neurotransmitters are not directly involved.