Bladder permeability barrier: recovery from selective injury of surface epithelial cells (original) (raw)
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American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2008
Increase in bladder mucosal permeability can be reproduced by intravesical administration of protamine sulfate (PS); however, the influence of PS once administered into the bladder disappears within several days. We developed a chronic animal model of urothelial injury using PS. Insertion of a polyethylene catheter through the bladder dome was performed in female Wistar rats. The other end of the catheter was connected to an osmotic pump for continuous delivery of PS or vehicle for 2 wk. Urinary frequency (UF) and voided volume (VV) were measured in the metabolic cage. The fifth group of rats received a high dose of PS (10 mg/ml) for 2 wk and were followed for a further 2 wk without PS. The sixth group received a high dose of PS for 2 wk and loxoprofen (0.1 mg·kg−1·day−1) for 4 wk. UF was increased, and VV was reduced in rats treated with a high dose of PS but not changed in rats treated with a vehicle or a low dose of PS (1 mg/ml). UF was further increased in the fifth group, while...
Urothelial permeability of the isolated whole bladder
Neurourology and Urodynamics, 1993
The urothelium of the bladder presents an effective barrier to the penetration of solutes from the urine into the bladder wall. Previously, we have demonstrated that the dye indigocarmine can be utilized intravesically to study urothelial permeability. In general, intravesical indigocarmine (administered in vivo) will not penetrate the bladder wall unless the urothelium is damaged by overdistension, acetone administration, or mechanical damage. Unfortunately, using in vivo methodologies, one is limited in the study of the effect of specific conditions and permeations on bladder permeability. In the current study an isolated in vitro whole bladder model was developed to quantitatively study the permeability of the bladder urothelium. In these studies, the penetration of indigocarmine into and through the bladder wall was quantitated under various conditions. The in vitro bladder was filled by infusing 1% indigocarmine in saline in a step-wise manner at the rate of 10 ml in 10 minutes followed by a stabilization period of 10 minutes. Samples were taken from the bath at 20 minutes intervals for spectrophotometrical analysis of the dye. At the end of experiment the bladder was washed in saline for 10 minutes, and stored and extracted in formalin. In general, no indigocarmine penetrated the urothelium until the in vitro capacity was reached and exceeded. At intravesical volumes greater than capacity, the dye concentration in the bath increased very rapidly, even though the integrity of the bladder wall remained intact. In bladders treated with a gentle 50% acetone wash for 1 minute the dye started to penetrate into the bath at intravesical volumes of 25% of capacity and increased rapidly thereafter. Heparin instillations both delayed the onset of dye penetration and reduced the magnitude of the dye penetration. In addition, heparin inhibited dye penetration only at low volumes. Although in vitro anoxia of 60 minutes induced only slight dye penetration into the bath, the dye concentration in the tissue increased substantially indicating that anoxia induced damage to the urothelium.These results indicate that an intact mucosal layer in the in vitro whole bladder model prevents indigocarmine penetration into and through the bladder wall, as it does in the in vivo bladder. Similar to the in vivo studies, there is a clear quantitative correlation between penetration of the dye and mucosal damage. Filling the bladder to capacity induced no mucosal damage. Only at volumes above capacity was the integrity compromised and permeability increased. The current model can be utilized to study mucosal permeability under controlled intravesical and extravesical conditions, as well as the study of permeability of bladders subjected to specific uropathologies. © 1993 Wiley-Liss, Inc.
The Journal of urology, 2015
To compare the relative permeability of the upper urinary tract and bladder urothelium to mitomycin C (MMC). Ex vivo porcine bladder, ureters and kidneys were dissected out and filled with 1 mg ml(-1) MMC. Following 60 min, organs were emptied and excised tissue samples sectioned parallel to the urothelium. Sectioned tissue was homogenised and extracted MMC quantified. Transurothelial permeation across the different urothelia was calculated by normalising the total amount of drug extracted to the surface area of the tissue sample. Average MMC concentrations at different tissue depths (concentration - depth profiles) were calculated by dividing the total amount of drug recovered by the total weight of tissue. MMC permeation across ureteral urothelium (9.07 μg cm(-2)) was significantly greater than across bladder (0.94 μg cm(-2)) or renal pelvis urothelium (3.61 μg cm(-2)). Concentrations of MMC in the ureter and kidney were markedly higher than those achieved in the bladder at all ti...
Evaluation of a novel preclinical model for bladder barrier evaluation using whole porcine bladders
Neurourology and Urodynamics, 2016
Hypothesis / aims of study Preclinical experimental models for evaluation of bladder permeability are important for investigating novel therapies for Interstitial Cystitis / Bladder Pain Syndrome (IC/BPS). This is often done with in vitro or small rodent models, whilst larger animal bladders like the porcine bladder is more biocompatible with the human bladder. The aim of this study was to evaluate the applicability of a new bioreactor in which the barrier properties of an intact porcine bladder can be investigated. Key factor for applicability of the model was the usage of readily available porcine bladders from freshly dissected bladders from the local abattoir.
Formation and maintenance of blood–urine barrier in urothelium
Protoplasma, 2010
Blood-urine barrier, which is formed during differentiation of superficial urothelial cells, is the tightest and most impermeable barrier in the body. In the urinary bladder, the barrier must accommodate large changes in the surface area during distensions and contractions of the organ. Tight junctions and unique apical plasma membrane of superficial urothelial cells play a critical role in the barrier maintenance. Alterations in the blood-urine barrier function accompany most of the urinary tract diseases. In this review, we discuss recent discoveries on the role of tight junctions, dynamics of Golgi apparatus and post-Golgi compartments, and intracellular membrane traffic during the biogenesis and maintenance of blood-urine barrier.
Improving the barrier function of damaged cultured urothelium using chondroitin sulfate
Neurourology and Urodynamics, 2019
Aims: To determine whether glycosaminoglycan (GAG) replenishment is able to improve recovery of a deficient urothelial barrier, chondroitin sulfate (CS) instillations were tested using an in vitro model. Porcine urothelial cells (Ucells) were terminally differentiated in culture conditions to construct a urothelial layer with a functional barrier. This layer was damaged to compromise barrier function to simulate a key characteristic of bladder pain syndrome/interstitial cystitis. The functional effect of subsequent treatment with CS was evaluated. Methods: Primary porcine Ucells were isolated and cultured on inserts. Differentiation of cells was evaluated with immunohistochemical analysis for the presence of umbrella cells, tight junctions and CS. Transepithelial electrical resistance (TEER) measurements were performed to evaluate barrier function. Protamine was used to simulate mild urothelial damage. CS 0.2% (vol/vol), a GAG, was subsequently instilled in the treatment group. The recovery of barrier function was further evaluated with TEER measurements. The Student t test was used for the analysis of results. Results: After induction of differentiation, the Ucells expressed barrier markers and a functional barrier was established (measured by high TEER). TEER decreased significantly after instillation with protamine. CS instillation improved recovery of TEER significantly measured after 7 hours (84% vs 22% in controls). After 24 hours; however, the TEER was comparable in both experimental groups. Conclusion: CS instillation improves the recovery of the urothelial barrier after damage in vitro. This functional experiment shows that CS improves recovery of damaged urothelial function, which supports the hypothesis behind the mechanism of action of GAG-replenishment therapy.
Is electrolyte transfer across the urothelium important?: ICI-RS 2015
Neurourology and Urodynamics
This article summarizes discussion at the International Consultation on Incontinence Research Society (ICI-RS) 2015 meeting of urine modification in the urinary tract by the urothelium. It considers the literature and proposes pertinent questions that need to be addressed to understand this phenomenon within a physiological context. METHODS Following the ICI-RS meeting, publications in PubMed relating to urine modification in the renal pelvis, ureter, and bladder were reviewed. RESULTS Historically, the urothelium has been simply considered as a passive, impermeable barrier, preventing contact between urine and the underlying cells. In addition to the ability of the umbrella cells to modify the surface area of the urothelium during bladder filling, the urothelium may also be involved in modifying urine composition. Several lines of evidence support the hypothesis that electrolytes and water can be reabsorbed by the urothelium and that this may have physiological relevance. Firstly, urothelial cells express several types of aquaporins and ion channels; the membrane expression of which is modulated by the extracellular concentration of ions including Na+. Secondly, studies of urine composition in the renal pelvis and bladder demonstrate urine modification, indicating that water and/or electrolyte transport has occurred. Thirdly, hibernating mammals, with urothelial and bladder wall histology similar to non-hibernating mammals are known to produce and reabsorb urine daily, during long periods of hibernation. CONCLUSIONS The phenomenon of urine modification by the urothelium may be physiologically important during normal bladder filling. Research should be focused on investigating how this may change in conditions of urinary dysfunction. 1 FUNCTIONAL EXPRESSION OF AQUAPORINS IN UROTHELIUM Aquaporins (AQP) are integral membrane proteins forming pores, which transport water, glycerol, and some solutes. 12 AQPs are known to be involved in fluid homeostasis, water transport, glycerol, and fat transport in kidney epithelial cells, vascular endothelial cells, adipocytes, and epidermal cells. At least seven AQPs, AQP-1, 2, 3, 4, 6, 7, 8, are functionally expressed in the kidney for water transport and urine concentration. 13 Their somewhat surprising expression in urothelial cells suggests that these cells may also be capable of water transport in the urinary tract, particularly the bladder. Gene expression of AQP-3, 4, 7, 9, and 11 has been demonstrated in fresh human urothelium, moreover, protein expression of AQP-3, 4, 7, and 9 was confirmed with immunofluorescence. 14 AQP-3 protein
AJP: Renal Physiology, 2007
Diseases and conditions affecting the lower urinary tract are a leading cause of dysfunctional sexual health, incontinence, infection and kidney failure. The growth, differentiation, and repair of the bladder's epithelial lining is regulated, in part, by fibroblast growth factor (FGF)-7 and -10 via a paracrine cascade originating in the mesenchyme (lamina propria) and targeting the receptor for FGF-7 and -10 within the transitional epithelium (urothelium). The FGF-7 gene is located at the 15q15-q21.1 locus on chromosome 15 and four exons generate a 3.852 kb mRNA. Five duplicated FGF-7 gene sequences that localized to chromosome 9 were predicted not to generate functional protein products, thus validating the use of FGF7-null mice as an experimental model. Recombinant FGF-7 and -10 induce proliferation of human urothelial cells in vitro and transitional epithelium of wild-type and FGF7-null mice in vivo. To determine the extent that induction of urothelial cell proliferation during the bladder response to injury is dependent on FGF-7, an animal model of partial bladder outlet obstruction was developed. Unbiased stereology was used to measure the percentage of proliferating urothelial cells between obstructed groups of wild-type and FGF7-null mice. The stereological analysis indicated that a statistical significant difference did not exist between the two groups, suggesting that FGF-7 is not essential for urothelial cell proliferation in response to partial outlet obstruction. In contrast, a significant increase in FGF-10 expression was observed in the obstructed FGF-7 null group, indicating that the compensatory pathway that functions in this model results in urothelial repair.