Animal Modelling of Interstitial Cystitis/Bladder Pain Syndrome / 대한배뇨장애요실금학회지

The etiology of interstitial cystitis/bladder pain syndrome (IC/BPS) remains elusive and may involve multiple causes. To better understand its pathophysiology, many efforts have been made to create IC/BPS models. Most existing models of IC/BPS strive to recreate bladder-related features by applying noxious intravesical or systemic stimuli to healthy animals. These models are useful to help understand various mechanisms; however, they are limited to demonstrating how the bladder and nervous system respond to noxious stimuli, and are not representative of the complex interactions and pathophysiology of IC/BPS. To study the various factors that may be relevant for IC/BPS, at least 3 different types of animal models are commonly used: (1) bladder-centric models, (2) models with complex mechanisms, and (3) psychological and physical stressors/natural disease models. It is obvious that all aspects of the human disease cannot be mimicked by a single model. It may be the case that several models, each contributing to a piece of the puzzle, are required to recreate a reasonable picture of the pathophysiology and time course of the disease(s) diagnosed as IC/BPS, and thus to identify reasonable targets for treatment.

Feline Interstitial Cystitis Enhances Mucosa-Dependent Contractile Responses to Serotonin / 대한배뇨장애요실금학회지

PURPOSE: To determine whether responses to serotonin are altered in bladder strips from cats diagnosed with a naturally occurring form of bladder pain syndrome/interstitial cystitis termed feline interstitial cystitis (FIC). METHODS: Full thickness bladder strips were isolated from aged matched healthy control cats and cats with clinically verified FIC. Bladder strips were mounted in an organ bath and connected to a tension transducer to record contractile activity. A serotonin dose response (0.01–10μM) was determined for each strip with the mucosa intact or denuded. RESULTS: Bladder strips from control and FIC cats contracted in response to serotonin in a dose-dependent manner. The normalized force of serotonin-evoked contractions was significantly greater in bladder strips from cats with FIC (n=7) than from control cats (n=4). Removal of the mucosa significantly decreased serotonin-mediated responses in both control and FIC bladder preparations. Furthermore, the contractions in response to serotonin were abolished by 1μM atropine in both control and FIC bladder strips. CONCLUSIONS: The effect of serotonin on contractile force, but not sensitivity, was potentiated in bladder strips from cats with FIC, and was dependent upon the presence of the mucosa in control and FIC groups. As atropine inhibited these effects of serotonin, we hypothesize that, serotonin enhances acetylcholine release from the mucosa of FIC cat bladder strips, which could account for the increased force generated. In summary, FIC augments the responsiveness of bladder to serotonin, which may contribute to the symptoms associated with this chronic condition.

Current Pharmacologic Approaches in Painful Bladder Research: An Update / 대한배뇨장애요실금학회지

The symptoms of interstitial cystitis (IC)/bladder pain syndrome (BPS) may have multiple causes and involve many contributing factors. Traditional treatments (intravesical instillations) have had a primary focus on the bladder as origin of symptoms without adequately considering the potential influence of other local (pelvic) or systemic factors. Systemic pharmacological treatments have had modest success. A contributing factor to the low efficacy is the lack of phenotyping the patients. Individualized treatment based on is desirable, but further phenotype categorization is needed. There seems to be general agreement that IC is a unique disease and that BPS is a syndrome with multiple pathophysiologies, but this has so far not been not been well reflected in preclinical research with the aim of finding new pharmacological treatments. Current research approaches, including anti-nerve growth factor treatment, anti-tumor necrosis factor-α treatment, activation of SHIP1 (AQX-1125), and P2X3 receptor antagonists, and α1-adrenoceptor antagonists are potential systemic treatments, implying that not only the bladder is exposed to the administered drug, which may be beneficial if the IC/BPS is a bladder manifestation of a systemic disease, or negative (adverse effects) if it is a local bladder condition. Local treatment approaches such as the antagonism of Toll-like receptors (which still is only experimental) and intravesical liposomes (with positive proof-of-concept), may have the advantages of a low number of systemic adverse effects, but cannot be expected to have effects on symptoms generated outside the bladder. Assessment of which of the treatment approaches discussed in this review that can be developed into useful therapies requires further studies.

Abnormal Sensory Protein Expression and Urothelial Dysfunction in Ketamine-Related Cystitis in Humans / 대한배뇨장애요실금학회지

PURPOSE: The aim of this study was to analyze patterns of sensory protein expression and urothelial dysfunction in ketamine-related cystitis (KC) in humans. METHODS: Biopsies of bladder mucosa were performed in 29 KC patients during cystoscopy. Then specimens were analyzed for tryptase, zonula occludens-1 (ZO-1), E-cadherin, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) with immunofluorescence staining and quantification. In addition, 10 healthy control bladder specimens were analyzed and compared with the KC specimens. Another 16 whole bladder specimens obtained from partial cystectomy were also analyzed for the muscarinic receptors M2 and M3, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), β-3 adrenergic receptors (β3-ARs), and the P2X₃ receptor by western blotting. In addition, 3 normal control bladder specimens were analyzed and compared with the KC specimens. RESULTS: The KC bladder mucosa revealed significantly less expression of ZO-1 and E-cadherin, and greater expression of TUNEL and tryptase activity than the control samples. The expression of M3 and β3-AR in the KC specimens was significantly greater than in the controls. The expression of iNOS, eNOS, M2, and P2X3 was not significantly different between the KC and control specimens. CONCLUSIONS: The bladder tissue of KC patients revealed significant urothelial dysfunction, which was associated with mast-cell mediated inflammation, increased urothelial cell apoptosis, and increased expression of the M3 and β3-AR.