Immunohistochemical evidence suggests repeated intravesical application of botulinum toxin A injections may improve treatment efficacy of interstitial cystitis/bladder pain syndrome.

UNLABELLED: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: A single set of botulinum toxin A (BoNT-A) injections relieves clinical symptoms of interstitial cystitis/bladder pain syndrome (IC/BPS), but lacks long-term effect. An inadequate anti-inflammatory effect is likely to cause treatment failure. The study shows that chronic inflammation and apoptotic signalling molecules are significantly reduced after repeated intravesical BoNT-A injection in patients with IC/BPS. It also shows that repeated BoNT-A injections are necessary to achieve greater success in the treatment of IC/BPS. OBJECTIVE: To investigate the mechanisms of action of botulinum toxin A (BoNT-A) treatment on interstitial cystitis/bladder pain syndrome (IC/BPS). PATIENTS AND METHODS: A total of 23 women with IC/BPS who received single intravesical BoNT-A injection were studied. Among them, 11 received three repeated injections every 6 months to improve their symptoms. Bladder biopsy was obtained before each BoNT-A injection and the clinical symptoms and urodynamic variables were recorded. Immunohistochemical (IHC) staining for TUNEL and mast cell activity, and western blotting analysis of tryptase, cytokines, Bax and phospho-p38 (p-p38) were carried out. We compared the clinical results and IHC data among baseline, single or repeated BoNT-A treatments. RESULTS: Single BoNT-A injection improved clinical symptoms, pain score and daytime urinary frequency. Mast cell activity and apoptotic cell count did not decrease significantly, while Bax and p-p38, but not tryptase, decreased significantly after a single BoNT-A injection. The 11 patients who received three repeated BoNT-A injections had significantly lower pain scores than the remaining patients (mean [SD]: 5.80 [2.27] vs. 3.03 [2.30], P = 0), glomerulation degree (mean [SD]: 1.80 [1.06] vs. 1.20 [1.06], P = 0.026) and global response scores (mean [SD]: 0.30 [0.92] vs. 1.20 [1.06], P = 0) after treatment. Tryptase, Bax, p-p38 and apoptotic cell counts all decreased significantly. 25-kD synaptosomal-associated protein also decreased after BoNT-A treatments, which confirmed the therapeutic effect of repeated BoNT-A injections. CONCLUSIONS: Chronic inflammation and apoptotic signalling molecules were significantly reduced after repeated BoNT-A injections in patients with IC/BPS. The IHC improvement was associated with clinical symptom improvement. Repeated BoNT-A injections are necessary to achieve a greater success rate in the treatment of IC/BPS.

Higher levels of cell apoptosis and abnormal E-cadherin expression in the urothelium are associated with inflammation in patients with interstitial cystitis/painful bladder syndrome.

OBJECTIVE: To investigate the relationships between suburothelial inflammation and urothelial dysfunction in interstitial cystitis/painful bladder syndrome (IC/PBlS). MATERIALS AND METHODS: Immunofluorescence staining of ki-67 (to assess cell proliferation), junction protein E-cadherin, tryptase (to assess mast cell activation) and TUNEL (to assess urothelial apoptosis) were performed in bladder tissues from 20 patients with IC/PBlS and from 6 control patients. The fluorescence intensity of E-cadherin was measured using the ImageJ method. The percentage of apoptotic cells, proliferated cells and activated mast cells were measured and quantified as positive cells (±SD) per area unit (4 µm(2)). RESULTS: The ratio of ki-67-positive cells in the bladder tissue of the patients with IC/PBlS was significantly down-regulated compared with that of the control patients (0.559 ± 0.658 vs. 1.23 ± 1.28, P = 0.001). TUNEL staining revealed a significantly higher number of apoptotic cells in the IC/PBlS bladder tissue compared with control bladder tissue (2.26 ± 2.04 v 0.051 ± 0.124, P = 0.000). The tryptase signal was significantly stronger in the IC/PBlS bladder tissue compared with that of control patients (6.16 ± 4.35 v 1.15 ± 0.436, P = 0.000). The apoptotic cell number in IC/PBlS bladder tissue correlated significantly with mast cell activation (P = 0.021). Immunofluorescence also showed a significantly lower distribution of E-cadherin in IC/PBlS bladder tissue compared with that of control patients (8.50 ± 6.83 v 17.2 ± 11.9, P = 0.000). Lower expression of E-cadherin in IC/PBlS bladder tissue was significantly correlated with higher visual analogue pain scores in patients with IC/PBlS (P= 0.008). CONCLUSIONS: The results of the present study suggest that urothelial homeostasis in IC/PBlS bladders was impaired, and abnormal urothelial function was significantly associated with chronic inflammation. The junctions between urothelial cells in IC/PBlS bladders were abnormal, which was associated with the patient's self-report pain scales.

Down regulation of vascular endothelial growth factor is associated with decreased inflammation after intravesical OnabotulinumtoxinA injections combined with hydrodistention for patients with interstitial cystitis--clinical results and immunohistochemistry analysis.

OBJECTIVE: To measure the expression of vascular endothelial growth factor (VEGF) in bladder tissue and improvement of clinical symptoms and inflammatory biomarkers after repeated onabotulinumtoxinA injections in patients with interstitial cystitis/bladder pain syndrome (IC/BPS). METHODS: Twenty-one patients with IC/BPS received 4 sets of intravesical 100-U onabotulinumtoxinA injections combined with hydrodistention. Assessments at baseline and 6 months after each treatment included O'Leary-Sant Symptom Score, bladder pain visual analog scale, functional bladder capacity (FBC), grade of glomerulations under cystoscopic hydrodistention, and urodynamic parameters. The bladder specimens at baseline and at the fourth treatment were investigated by western blotting for the expression of VEGF, Bcl-2-associated X protein (Bax), and phospho-p38 (p-p38), and immunohistochemistry staining for apoptotic and mast cell activity. Six women with genuine stress urinary incontinence served as controls for comparison. RESULTS: The measured immunohistochemical parameters were significantly higher in patients with IC/BPS than the controls. Statistically significant decrease in the expression of VEGF was noted in patients treated with repeated onabotulinumtoxinA injections compared with baseline (0.83 ± 0.28 vs 1.00; P = .016). The apoptotic cell count (0.86 ± 1.00 vs 1.76 ± 1.69; P = .026) and mast cell activity (1.81 ± 2.29 vs 5.82 ± 4.97; P = .009) were also reduced. Significant increases in FBC and global response assessment score were also observed after onabotulinumtoxinA treatment; however, except for mast cell activity, VEGF expression and apoptotic cell count were still significantly higher than the controls. CONCLUSION: Increased VEGF was associated with bladder inflammation and smaller FBC in patients with IC/BPS and decreased after repeated onabotulinumtoxinA injections and hydrodistention, suggesting VEGF plays an important role in the pathogenesis of IC/BPS.

Increased cell apoptosis of urothelium mediated by inflammation in interstitial cystitis/painful bladder syndrome.

OBJECTIVE: To investigate whether bladder inflammation could directly modulate the signaling pathway of increased urothelial cell apoptosis in interstitial cystitis/painful bladder syndrome (IC/PBS). Chronic inflammation and impaired urothelial homeostasis are possible pathogenesis of IC/PBS. METHODS: A total of 29 patients with IC/PBS and 5 control patients were enrolled in the present study. Double stain, protein array analysis, and Western blotting were performed to analyze the alterations of caspase 3, Bad, Bax, phospho-p53, phospho-p38α, and tumor necrosis factor-α (TNF-α) in bladder mucosa specimens from patients with IC/PBS and control patients. The intensities of the proteins in the arrays and Western blots were quantified using ImageJ processing. Inflammatory molecule-treated urothelial cells were analyzed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and Western blotting for the level of molecules involved in apoptosis. RESULTS: Phospho-p38 and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling double staining indicated that inflammatory and apoptotic events coexisted in the IC/PBS bladder. Protein-antibody array analysis showed that several inflammatory molecules were increased in the IC/PBS samples. We also found that the levels of pro-apoptotic proteins, including phospho-p53 (Ser 15), Bad, Bax, and cleaved caspase-3 were significantly increased in the IC/PBS bladders. These results were confirmed by immunoblotting and suggested that the tissue damage and abnormal urothelium in the IC/PBS bladder might be regulated concurrently by inflammatory signals, such as p38 mitogen-activated protein kinase and TNF-α. The in vitro analysis also showed that the apoptotic process could be induced by TNF-α treatment and anisomycin stimulation in normal urothelial cells. CONCLUSION: Apoptosis of urothelial cells in patients with IC/PBS could result from upregulation of inflammatory signals, including p38 mitogen-activated protein kinase and TNF-α.

Differences in mast cell infiltration, E-cadherin, and zonula occludens-1 expression between patients with overactive bladder and interstitial cystitis/bladder pain syndrome.

OBJECTIVE: To investigate the difference of infiltration of mast cells and the distribution of protein involved in the urothelial barrier function between patients with overactive bladder syndrome (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS). METHODS: Bladder wall biopsies were performed in 27 patients with OAB, 18 patients with IC/BPS, and 19 controls. The expression of junction protein E-cadherin, tight junction protein zonula occludens (ZO-1), and activated mast cells in the bladder wall were evaluated quantitatively using immunofluorescence staining. RESULTS: The numbers of mast cells in the urothelium and suburothelium areas were low in the control group (mean ± standard error 1.77 ± 0.47). A highly significant increase in mast cell infiltration was observed in OAB (4.00 ± 0.55, P = .002) and IC/BPS specimens (4.64 ± 0.72, P = .000). ZO-1 expression was significantly decreased in IC/PBS (7.45 ± 0.99) compared with OAB (13.46 ± 1.32, P = .004) and control bladder samples (14.55 ± 2.08, P = .004). The E-cadherin expression was also significantly decreased in IC/BPS bladder samples (59.05 ± 9.48) compared with the controls (96.30 ± 9.15, P = .001). No significant difference was found in E-cadherin or ZO-1 levels between the OAB and control bladders (P = .170 and P = .763, respectively). CONCLUSION: Mast cell infiltration was found in both OAB and IC/BPS bladder wall, but E-cadherin and ZO-1 expression was only decreased in IC/BPS, suggesting the urothelial barrier function was not affected in the OAB bladder.