Changes in aquaporin 1 expression in rat urinary bladder after partial bladder outlet obstruction: preliminary report

Potential role for vitamin D vs. intermittent fasting in controlling aquaporin-1 and aquaporin-3 expression in HFD-induced urinary bladder alterations in rats

Background: High-fat diet-induced obesity is linked to suppression of aquaporins (AQPs) expression in different tissues. Both vitamin D and intermittent fasting were identified to enhance AQPs expression. In the urinary bladder, AQP-1 and AQP-3 mRNA transcripts were identified. Vitamin D has an impact on a variety of genes that encode proteins that control cell proliferation, differentiation, and death. Aim: To assess potential benefits of vitamin D and intermittent fasting (IF) and to explore alterations to the urinary bladder triggered by high-fat diet (HFD) in a rat model of obesity. Methods: Each of the 4 groups contained six adult male albino rats; control: a standard rodent chew for 12 weeks, HFD: HFD and fructose were administered orally via gastric gavage for 12 weeks, and vitamin D: HFD and fructose were administered orally for 8 weeks, then 4 weeks of intraperitoneal injection of vitamin D (5 microns/Kg/2 days) and IF group: Received intraperitoneal injections of vitamin D (5 microns/Kg/2 days) for 4 weeks after consumption of HFD and fructose orally for 8 weeks. The serum lipid profile was conducted at end of the experiment. In the bladder homogenates, the levels of oxidative stress indicators were assessed. Quantitative real-time PCR was performed on recently collected bladder samples. AQP-1 and AQP-3 immunohistochemistry was done. Results: When compared to the HFD group, the vitamin D and IF groups both demonstrated a substantial improvement in histopathological, immunohistochemical, biochemical, and molecular markers. Conclusion: In all examined parameters, IF exceeded vitamin D as a preventive factor for the urinary bladder deterioration.

Expression of NGF, MCP-1, uroplakin III, and NOS in bladder urothelium after partial urethral obstruction in rats

INTRODUCTION

Although several cytokines, chemokines, and growth factors have been suggested to play a role in the development of bladder fibrosis and functional changes, the mechanisms that are effective in the pathogenesis of partial bladder outlet obstruction (pBOO)-induced bladder fibrosis are not well understood.

OBJECTIVE

We investigated the expressions of nerve growth factor (NGF), monocyte chemoattractant protein-1 (MCP-1), uroplakin III (URPIII), inducible nitric oxide synthase (iNOS), and endothelial NOS (eNOS) that may be involved in fibrosis in rats with partial urethral obstruction for 1, 2 and 3 weeks, and the changes in the associated ischemic and inflammatory processes. After 1, 2, and 3 weeks of pBOO, blood samples were collected for assessment of renal function from the rats under anesthesia. The bladders were dissected for the tissue antioxidant enzyme activities and lipid peroxidation, including malondialdehyde (MDA), superoxide dismutase (SOD), total antioxidant status (TAS) and total oxidant status (TOS). The immunohistochemical studies were performed. Histopathologically, the number of urothelial layers was calculated and the thickness of the detrusor smooth muscle and lamina propria were quantitatively measured. Additionally, the edema and congestion in the submucosa were evaluated.

STUDY DESIGN

Twenty-eight male Sprague-Dawley rats were used in this study. Three separate experimental groups of pBOO (1 week [n = 7], 2 weeks [n = 7], and 3 weeks [n = 7]) were created, with an additional sham-operated control group (n = 7).

RESULTS

The MDA levels increased in pBOO groups. The SOD values were decreased in the pBOO group for 1 week, and higher in the 3-week pBOO group. The TAS levels were increased in the 3 week pBOO group. The TOS levels increased in the pBOO groups. The number of urothelial layers was decreased in pBOO groups. The lamina propria, the smooth muscle thickness, edema and congestion were increase in the 1 and 2 week pBOO groups. The NGF and MCP-1 expression was increased in the 1-week and 2-week pBOO groups. The expression of URPIII in the epithelium gradually increased in the pBOO groups. In the pBOO groups, iNOS expression in the epithelium cells was significantly elevated. However, the eNOS expression was also significantly increased in the 2 week pBOO group.

CONCLUSION

Our study shows that overexpression of immunohistochemical parameters together with the negative effects of ischemic and inflammatory processes that subjected to pBOO for 1, 2 and 3 weeks may play a potential role in detrusor fibrosis in the rat bladders induced by pBOO. However, understanding of the immunohistochemical parameters investigated in this experimental study is limited, and further studies targeting their relationship to pBOO could help us develop new strategies.

The Vacuolating Autotransporter Toxin (Vat) of Escherichia coli Causes Cell Cytoskeleton Changes and Produces Non-lysosomal Vacuole Formation in Bladder Epithelial Cells

Urinary tract infections (UTIs) affect more than 150 million people, with a cost of over 3.5 billion dollars, each year. Escherichia coli is associated with 70–80% of UTIs. Uropathogenic E. coli (UPEC) has virulence factors including adhesins, siderophores, and toxins that damage host cells. Vacuolating autotransporter toxin (Vat) is a member of serine protease autotransporter proteins of Enterobacteriaceae (SPATEs) present in some uropathogenic E. coli (UPEC) strains. Vat has been identified in 20–36% of UPEC and is present in almost 68% of urosepsis isolates. However, the mechanism of action of Vat on host cells is not well-known. Thus, in this study the effect of Vat in a urothelium model of bladder cells was investigated. Several toxin concentrations were tested for different time periods, resulting in 15–47% of cellular damage as measured by the LDH assay. Vat induced vacuole formation on the urothelium model in a time-dependent manner. Vat treatment showed loss of the intercellular contacts on the bladder cell monolayer, observed by Scanning Electron Microscopy. This was also shown using antibodies against ZO-1 and occludin by immunofluorescence. Additionally, changes in permeability of the epithelial monolayer was demonstrated with a fluorescence-based permeability assay. Cellular damage was also evaluated by the identification of cytoskeletal changes produced by Vat. Thus, after Vat treatment, cells presented F-actin distribution changes and loss of stress fibers in comparison with control cells. Vat also modified tubulin, but it was not found to affect Arp3 distribution. In order to find the nature of the vacuoles generated by Vat, the Lysotracker deep red fluorescent dye for the detection of acidic organelles was used. Cells treated with Vat showed generation of some vacuoles without acidic content. An ex vivo experiment with mouse bladder exposed to Vat demonstrated loss of integrity of the urothelium. In conclusion, Vat induced cellular damage, vacuole formation, and urothelial barrier dysregulation of bladder epithelial cells. Further studies are needed to elucidate the role of these vacuoles induced by Vat and their relationship with the pathogenesis of urinary tract infection.

Urine Composition in Pigs is Regulated in Both the Ureter and the Bladder

The former perception of the urothelium as an impermeable barrier has been revised during the last decade, as increasing evidence of changes in urine composition during its passage of the urinary tract has been presented. Since differences in urothelial permeability between upper and lower urinary tract have been found, our aim is to demonstrate whether changes in urine composition occur during passage through the ureter. We studied consecutive urine samples from both renal pelvises in six pigs and compared them to samples from the bladder and distal ureter. We further sampled urine during storage in the bladder at a fixed volume. All samples were analysed by measuring osmolality and pH, along with the concentration of the following parameters: Na+, K+, Cl-, creatinine, urea. Urine alkalinity increased significantly during passage of the ureter. Creatinine concentration, pH and K+ increased significantly during the passage from pelvis to the bladder. All other parameters increased non-significantly during the passage to the bladder. The increase in concentration was more pronounced at low concentrations in the pelvis. During storage in the bladder, there was a significant increase in urea concentration. Changes in the composition of urine occur during its passage from the renal pelvis to the bladder and during storage in the bladder. Despite the brief transit time, significant changes in alkalinity were found already during passage through the ureter.

Aquaporin expression in the fetal porcine urinary tract changes during gestation

The expression of aquaporins (AQPs) in the fetal porcine urinary tract and its relation to gestational age has not been established. Tissue samples from the renal pelvis, ureter, bladder and urethra were obtained from porcine fetuses. Samples were examined by RT-PCR (AQPs 1-11), QPCR (AQPs positive on RT-PCR), and immunohistochemistry. Bladder samples were additionally examined by Western blotting. RNA was extracted from 76 tissue samples obtained from 19 fetuses. Gestational age was 60 (n=11) or 100 days (n=8). PCR showed that AQP1, 3, 9 and 11 mRNA was expressed in all locations. The expression of AQP3 increased significantly at all four locations with gestational age, whereas AQP11 significantly decreased. AQP1 expression increased in the ureter, bladder and urethra. AQP9 mRNA expression increased in the urethra and bladder, but decreased in the ureter. AQP5 was expressed only in the urethra. Immunohistochemistry showed AQP1 staining in sub-urothelial vessels at all locations. Western blotting analysis confirmed increased AQP1 protein levels in bladder samples during gestation. Expression levels of AQP1, 3, 5, 9 and 11 in the urinary tract change during gestation, and further studies are needed to provide insights into normal and pathophysiological water handling mechanisms in the fetus.

Establishment and value assessment of efficacy prediction model about transurethral prostatectomy

OBJECTIVES

To establish and to evaluate discriminant models to predict the outcomes of transurethral prostatectomy.

METHODS

Clinical data of patients treated with transurethral prostatectomy between January and December 2013 were collected, including medical history, symptoms, biochemical tests, ultrasonography and urodynamics. Surgical efficacy was evaluated at 6-month follow up. Predictive models were constructed by logistic regression. Receiver operating characteristic curve and diagnostic tests were used to test the accuracy of models before the predictive value between models was compared.

RESULTS

A total of 182 patients were included, with 73.6% having an effective outcome. History of recurrent urinary tract infection (OR 1.33), score of storage phase (OR 2.58), maximum flow rate (OR 2.11) and detrusor overactivity (OR 3.13) were found to be risk factors. International Prostate Symptom Score (OR 0.13), transitional zone index (OR 0.58), resistive index of prostatic artery (OR 0.46), bladder wall thickness (OR 0.78), ultrasonic estimation of bladder weight (OR 0.28), bladder outlet obstruction index (OR 0.20) and bladder contractility index (OR 0.83) were found to be protective factors. The areas under the curve of models using factors from ultrasonography and urodynamics were 0.792 and 0.829 respectively, with no significant difference being found between them (P = 0.348).

CONCLUSIONS

Surgical efficacy of transurethral prostatectomy is positively correlated to severe voiding phase symptoms, outlet obstruction and better detrusor contractility, and negative correlated with urinary infection, severe storage phase symptoms and excessive detrusor contractibility. Ultrasonography might replace urodynamics in selecting patients for whom transurethral prostatectomy is more likely to be beneficial.

The impact of the bladder wall thickness on the outcome of the medical treatment using alpha-blocker of BPH patients with LUTS

OBJECTIVES

To evaluate whether the outcome of medical treatment with α 1 receptor blocker in Benign prostatic hyperplasia (BPH) patients with lower urinary tract symptoms (LUTS) is affected by the bladder wall thickness (BWT) Methods: A total of 125 male BPH patients with LUTS were enrolled. All patients were assessed using The International Prostatic Symptom Score (IPSS), prostate specific antigen (PSA), prostate volume, uroflowmetry, post voiding residual (PVR). BWT was measured by Trans-abdominal ultrasound, and patients were divided into two groups group 1 (patients with BWT <5 mm) and group 2 (patients with BWT ≥5 mm). The patients were reassessed after 2 months of treatment with α 1 receptor blocker (alfuzosin 10 mg). Clinical parameters were analyzed and compared between groups.

RESULTS

There were significant difference between both groups as regard IPSS, voiding symptoms, and storage symptoms (p = 0.005), (p = 0.010) and (p = 0.041) respectively. After medication, there were improvements in the total IPSS, voiding symptoms, storage symptoms, Qmax, PVR and Qol in both groups and these improvements were more effectively in (group 1) than (group 2) with statistically significant differences (p < 0.05).

CONCLUSION

BWT has positive correlation with the total IPSS, voiding symptoms subscores and storage symptoms subscores. The response to medical treatment is found statistically less in patients with BWT greater than 5 mm.

Loss of Caveolin 1 is Associated With the Expression of Aquaporin 1 and Bladder Dysfunction in Mice

Purpose:

It is suggested that caveolin and aquaporin might be closely associated with bladder signal activity. We investigated the effect of the deletion of caveolin 1, using caveolin 1 knockout mice, on the expression of aquaporin 1 in order to identify their relation in the urothelium of the urinary bladder.

Methods:

The cellular localization and expressions of aquaporin 1 and caveolin 1, in the wild type and caveolin 1 knockout mice urinary bladder, were examined by Western blot and immunofluorescence techniques.

Results:

Aquaporin 1 and caveolin 1 were coexpressed in the arterioles, venules, and capillaries of the suburothelial layer in the wild type controls. Aquaporin 1 protein expression was significantly higher in the caveolin 1 knockout mice than in the wild type controls (P <0.05).

Conclusions:

The results imply that aquaporin 1 and caveolin 1 may share a distinct relation with the bladder signal activity. This might play a specific role in bladder dysfunction.

Overexpression of aquaporin-1 and caveolin-1 in the rat urinary bladder urothelium following bladder outlet obstruction

PURPOSE

This study was designed to investigate the effect of detrusor overactivity induced by partial bladder outlet obstruction (BOO) on the expression of aquaporin 1 (AQP1) and caveolin 1 (CAV1) in the rat urinary bladder, and to determine the role of these molecules in detrusor overactivity.

METHODS

Female Sprague-Dawley rats were divided into control (n=30) and experimental (n=30) groups. The BOO group underwent partial BOO, and the control group underwent a sham operation. After 4 weeks, an urodynamic study was performed to measure the contraction interval and contraction pressure. The expression and cellular localization of AQP1 and CAV1 were determined by western blot and immunofluorescence experiments in the rat urinary bladder.

RESULTS

In cystometrograms, the contraction interval was significantly lower in the BOO group (2.9±1.5 minutes) than in the control group (6.7±1.0 minutes) (P<0.05). Conversely, the average contraction pressure was significantly higher in the BOO group (21.2±3.3 mmHg) than in the control group (13.0±2.5 mmHg) (P<0.05). AQP1 and CAV1 were coexpressed in the capillaries, arterioles, and venules of the suburothelial layer. AQP1 and CAV1 protein expression was significantly increased in the BOO rats compared to the control rats (P<0.05).

CONCLUSIONS

Detrusor overactivity induced by BOO causes a significant increase in the expression of AQP1 and CAV1, which were coexpressed in the suburothelial microvasculature. This finding suggests that AQP1 and CAV1 might be closely related to bladder signal activity and may have a functional role in BOO-associated detrusor overactivity.

Bladder Wall Thickness is Associated with Responsiveness of Storage Symptoms to Alpha-Blockers in Men with Lower Urinary Tract Symptoms

Purpose

Bladder wall thickness (BWT) is reported to be related to detrusor overactivity and bladder outlet obstruction. We investigated the relationship between BWT and the responsiveness of storage symptoms to alpha-blockers in men with lower urinary tract symptoms (LUTS).

Materials and Methods

A total of 74 patients with LUTS were enrolled. International Prostate Symptom Score, uroflowmetry with post-void residual urine volume, and transrectal ultrasonography (TRUS) were investigated. BWT was measured by performing TRUS at the midsagittal plane view, and the average value of BWT at the anterior, dome, and trigone areas was used. After 4 weeks of alpha-blocker medication, patients were reevaluated and divided into two groups. The responder group consisted of patients who reported improvement in the storage symptom subscore of 2 points or more; the non-responder group consisted of patients who reported improvement of less than 2 points. Clinical parameters including BWT were compared between the two groups.

Results

A total of 52 patients were followed. BWT was positively correlated with intravesical prostate protrusion (IPP) (9.26±4.99, standardized beta=0.393, p=0.002) and storage symptom subscore (0.35±0.43, standardized beta=0.458, p=0.002). Compared with that in the responder group, BWT was thicker in the non-responder group, and improvement in the storage symptom score was correlated with BWT (0.58±0.09 cm vs. 0.65±0.11 cm, p=0.018) and prostate volume (27.08±16.26 ml vs. 36.44±10.1 ml, p=0.018).

Conclusions

BWT was correlated with IPP, the storage symptom subscore, and the responsiveness of storage symptoms to alpha-blockers in LUTS/benign prostatic hyperplasia (BPH) patients. As BWT increased, the responsiveness of storage symptoms to alpha-blocker decreased in LUTS/BPH patients.

Expression of nitric oxide synthase and aquaporin-3 in cyclophosphamide treated rat bladder

PURPOSE

The expression of Nitric oxide Synthase (NOS) and aquaporin (AQP) water channels in rat bladder is recently reported. The aim of this study is to evaluate the expression of inducible NOS (iNOS), aquaporin-3 (AQP-3) in cyclophosphamide (CYP) induced rat bladder.

MATERIALS AND METHODS

The 32 Sprague-Dawley rats were divided into cystitis group (n=20) and control group (n=12). In cystitis group, 100mg/kg CYP was injected every second day for 1 week whereas in control group, normal saline was injected. After extracting of the bladder and dividing dome, body and trigone of the bladder, independently H&E staining and immunohistochemical staining for iNOS and AQP-3 were performed. Expressions of iNOS and AQP-3 were analyzed with a confocal laser scanning microscope and an image analyzer.

RESULTS

The expression of iNOS significantly increased in the mucosa, submucosa layer of dome in cystitis group (p<0.05). The expression of AQP-3 significantly increased in the mucosa, submucosa, vessel layer of dome in cystitis group (p<0.05).

CONCLUSIONS

These results suggest that inflammatory change activates NOS and AQP-3 expression in the bladder tissue of rats. These may imply that NOS and AQP-3 have a pathophyiological role in the cyclophophamide induced interstitial cystitis. Further study on the NOS and AQP-3 in bladder is needed for clinical application.