In the absence of overt urothelial damage, chondroitinase ABC digestion of the GAG layer increases bladder permeability in ovariectomized female rats.

Loss of integrity of the protective impermeability barrier in the urothelium has been identified as significant in bladder dysfunction. In this study, we tested the theory that the luminal layer of glycosaminoglycans (GAG) serves as an important component of barrier function. The peptide polycation protamine sulfate (PS), 1 mg/ml, was instilled intravesically for 10 min into rat bladders. Chondroitinase ABC (ChABC), 63 IU/ml, was instilled into an additional six rats for 30 min to digest the GAG layer. Unmanipulated controls and sham-injected controls were also performed. After 24 h, the rats were euthanized, the bladders were removed, and permeability was assessed in the Ussing chamber and by diffusion of FITC-labeled dextran (4 kDa) to measure macromolecular permeability. The status of tight junctions was assessed by immunofluorescence and electron microscopy. In control and sham treated rat bladders, the transepithelial electrical resistance were means of 2.5 ± 1.1 vs. 2.6 ± 1.1 vs 1.2 ± 0.5 and 1.01 ± 0.7 kΩ·cm(2) in the PS-treated and ChABC-treated rat bladders (P = 0.0016 and P = 0.0039, respectively). Similar differences were seen in dextran permeability. Histopathology showed a mild inflammation following PS treatment, but the ChABC-treated bladders were indistinguishable from controls. Tight junctions generally remained intact. ChABC digestion alone induced bladder permeability, confirming the importance of the GAG layer to bladder barrier function and supports that loss of the GAG layer seen in bladder biopsies of interstitial cystitis patients could be a significant factor producing symptoms for at least some interstitial cystitis/painful bladder syndrome patients.

A Feasibility Study to Determine Whether Clinical Contrast Enhanced Magnetic Resonance Imaging can Detect Increased Bladder Permeability in Patients with Interstitial Cystitis.

PURPOSE: Interstitial cystitis/bladder pain syndrome is a bladder pain disorder associated with voiding symptomatology and other systemic chronic pain disorders. Currently diagnosing interstitial cystitis/bladder pain syndrome is complicated as patients present with a wide range of symptoms, physical examination findings and clinical test responses. One hypothesis is that interstitial cystitis symptoms arise from increased bladder permeability to urine solutes. This study establishes the feasibility of using contrast enhanced magnetic resonance imaging to quantify bladder permeability in patients with interstitial cystitis. MATERIALS AND METHODS: Permeability alterations in bladder urothelium were assessed by intravesical administration of the magnetic resonance imaging contrast agent Gd-DTPA (Gd-diethylenetriaminepentaacetic acid) in a small cohort of patients. Magnetic resonance imaging signal intensity in patient and control bladders was compared regionally and for entire bladders. RESULTS: Quantitative assessment of magnetic resonance imaging signal intensity indicated a significant increase in signal intensity in anterior bladder regions compared to posterior regions in patients with interstitial cystitis (p <0.01) and significant increases in signal intensity in anterior bladder regions (p <0.001). Kurtosis (shape of probability distribution) and skewness (measure of probability distribution asymmetry) were associated with contrast enhancement in total bladders in patients with interstitial cystitis vs controls (p <0.05). Regarding symptomatology interstitial cystitis cases differed significantly from controls on the SF-36®, PUF (Pelvic Pain and Urgency/Frequency) and ICPI (Interstitial Cystitis Problem Index) questionnaires with no overlap in the score range in each group. ICSI (Interstitial Cystitis Symptom Index) differed significantly but with a slight overlap in the range of scores. CONCLUSIONS: Data suggest that contrast enhanced magnetic resonance imaging provides an objective, quantifiable measurement of bladder permeability that could be used to stratify bladder pain patients and monitor therapy.

Mechanisms of Visceral Organ Crosstalk: Importance of Alterations in Permeability in Rodent Models.

PURPOSE: The pathophysiology of painful bladder syndrome is poorly understood. However, there is evidence of female predominance and comorbidity with irritable bowel syndrome. Our hypothesis is that cross-sensitization between bladder and colon is due to altered permeability in 1 organ, which affects the other organ. MATERIALS AND METHODS: Experiments were performed in anesthetized, ovariectomized female rats. In separate groups protamine sulfate was infused in the bladder or trinitrobenzene sulfonic acid was infused in the colon. Untreated rats served as controls. Bladder and colonic tissue were harvested from all rats 1, 3 and 5 days after treatment. Permeability was assessed in vitro in Ussing chambers by measuring transepithelial electrical resistance and macromolecular flux of fluorescein isothiocyanate-dextran. RESULTS: Exposing the bladder to protamine sulfate induced a significant decrease in bladder transepithelial electrical resistance and an increase in the translocation of fluorescein isothiocyanate across the tissue compared to controls at 1 and 3 days (p <0.05). Colonic tissue from rats with enhanced bladder permeability showed a significant decrease in transepithelial electrical resistance and increase in fluorescein isothiocyanate compared to untreated controls at all time points (p <0.05). Conversely when colonic permeability was increased with trinitrobenzene sulfonic acid, we observed an increase in bladder permeability in the absence of any changes to the bladder urothelium. CONCLUSIONS: Changes in epithelial permeability may represent a novel mechanism for visceral organ crosstalk. It may explain the overlapping symptomology of painful bladder syndrome and irritable bowel syndrome.

Contrast enhanced magnetic resonance imaging as a diagnostic tool to assess bladder permeability and associated colon cross talk: preclinical studies in a rat model.

PURPOSE: Interstitial cystitis/painful bladder syndrome is a devastating disease associated with multiple symptoms. It is usually diagnosed based on pain, urgency and frequency in the absence of other known causes. To our knowledge there is no diagnostic test to date. MATERIALS AND METHODS: In a model of rats intravesically exposed to protamine sulfate we performed in vivo diagnostic contrast enhanced magnetic resonance imaging with intravesical administration of Gd-diethylenetriamine pentaacetic acid contrast medium via a catheter to visualize increased bladder urothelium permeability. Gd-diethylenetriamine pentaacetic acid was administered intravenously to visualize secondary tissue effects in the colon. RESULTS: Bladder urothelium and colon mucosa were assessed 24 hours after bladder protamine sulfate exposure. Enhanced contrast magnetic resonance imaging established bladder urothelium leakage of Gd-diethylenetriamine pentaacetic acid according to the change in magnetic resonance imaging signal intensity in rats exposed to protamine sulfate vs controls (mean ± SD 399.7% ± 68.7% vs 39.2% ± 12.2%, p < 0.0001) as well as colon related uptake of contrast agent (mean 65.2% ± 17.1% vs 20.8% ± 9.8%, p < 0.01) after bladder protamine sulfate exposure. The kinetics of Gd-diethylenetriamine pentaacetic acid uptake and excretion were also assessed during 20 minutes of bladder and 30 minutes of colon exposure with increased signal intensity at 7 and 12 minutes, respectively. CONCLUSIONS: These preliminary studies indicate that contrast enhanced magnetic resonance imaging can be used to monitor primary bladder urothelium loss of permeability and secondary enhanced contrast medium in the colon mucosa. It can be considered a potential clinical diagnostic method for interstitial cystitis/painful bladder syndrome that involves loss of the permeability barrier. It can also be used to assess visceral organ cross talk.