Telocytes and ezrin expression in normal-appearing tissues adjacent to urothelial bladder carcinoma as predictors of invasiveness and recurrence.

Recurrence and progression rates vary widely among different histological subtypes of bladder cancer (BC). Normal-appearing mucosa in non-muscle invasive bladder cancer and muscle-invasive bladder cancer in cystoscopy and histopathology is a factor in staging and treatment. Telocytes (TCs) are spindle-shaped cells that connect with other cell types allowing communication though cytoskeletal signaling. They are involved in tissue regeneration and pathogenesis of diseases and cancer. In this study, 12 normal-appearing tissues from urinary bladder with BC, both invasive and non-invasive were evaluated in patients who had either trans-urethral resection of bladder tumor or cystectomy. In each case, cystoscopy, intraoperative inspection, and histopathology all confirmed the absence of cancerous elements. Five patients with neurogenic bladder were used as a control group. Immunohistochemistry revealed that c-Kit + cells were intensively distributed in bladder layers from BC samples, while they were seldom detected in the control group. Ultrastructural examination of reprocessed tissue showed an intense distribution of TCs and telopodes in the submucosa and between smooth muscle cells in BC. Telopodes were numerous, arborizing, and intercommunicating. Whereas TCs and telopodes were scarce in the neurogenic bladder. Also, cancerous tissue had the highest expression level of ezrin protein, and this level gradually decreased as we moved away from the tumor. Our finding of TCs number in normal-appearing tissues in conjunction with ezrin expression may compete invasiveness and possibly a trail to reduce recurrence rates.

Moxibustion attenuates neurogenic detrusor overactivity in spinal cord injury rats by inhibiting M2/ATP/P2X3 pathway.

PURPOSE: Activation of muscarinic receptors located in bladder sensory pathways is generally considered to be the primary contributor for driving the pathogenesis of neurogenic detrusor overactivity following spinal cord injury. The present study is undertaken to examine whether moxibustion improves neurogenic detrusor overactivity via modulating the abnormal muscarinic receptor pathway. MATERIALS AND METHODS: Female Sprague-Dawley rats were subjected to spinal cord injury with T9-10 spinal cord transection. Fourteen days later, animals were received moxibustion treatment for one week. Urodynamic parameters and pelvic afferents discharge were measured. Adenosine triphosphate (ATP) content in the voided cystometry fluid was determined. Expressions of M2, M3, and P2X3 receptors in the bladder mucosa were evaluated. RESULTS: Moxibustion treatment prevented the development of detrusor overactivity in spinal cord injury rats, with an increase in the intercontraction interval and micturition pressure threshold and a decrease in afferent activity during filling. The expression of M2 was markedly suppressed by moxibustion, accompanied by a reduction in the levels of ATP and P2X3. M2 receptor antagonist methoctramine hemihydrate had similar effects to moxibustion on bladder function and afferent activity, while the M2-preferential agonist oxotremorine methiodide abolished the beneficial effects of moxibustion. CONCLUSION: Moxibustion is a potential candidate for treating neurogenic bladder overactivity in a rat model of spinal cord injury, possibly through inhibiting the M2/ATP/P2X3 pathway.

Non-invasive markers in the management of pediatric neurogenic bladder over the last two decades - A review.

Neurogenic bladder (NB) is one of the most challenging problems in nephro-urological management in pediatrics. It is an important risk factor of secondary upper urinary tract damage. A complete clinical evaluation is necessary and requires life-long extensive medical attention including invasive procedures that affect patients' quality of life. Potential non-invasive biomarkers would be desirable, especially in the pediatric population. The aim of this review was to analyze two decades of data regarding potential non-invasive biomarkers in the assessment and follow-up of children with NB. This paper summarizes and appraises the knowledge about both biochemical and imaging-based markers in 3 aspects: markers of urinary tract infections (UTIs), bladder and renal function, and this paper looks at their prospective application in everyday clinical care.

The TGF-ß1 pathway is early involved in neurogenic bladder fibrosis of juvenile rats.

BACKGROUND: This study investigated whole neurogenic bladder's progression changes, as well as the expression of TGF-ß1 fibrosis pathway-related proteins in bilateral spinal nerve-amputated juvenile rats. METHODS: Sixty-four 8-week-old rats (32 bilateral L6 + S1 spinal nerve amputated and 32 sham operated) were selected. Cystometry was performed. General assessments, Masson, Sirius red, immunohistochemical staining, and western blotting of fibrosis and TGF-ß1 pathway-related proteins were conducted using bladder tissues. RESULTS: Cystometry results showed that the basal intravesical pressures and bladder capacities in nerve-amputated rats were significantly higher than those in sham-operated ones. Compared to the sham-operated groups, the bladder size and wall thickness in the nerve-amputated groups increased initially but then decreased over time. However, bladder weight continuously increased over time. Disintegration, thickening, and hypertrophy of the bladder wall were found over time in the amputated rats. Moreover, there was a significant increase in collagen III, and the ratio of collagen III/I was higher in amputated rats (P < 0.01). Finally, the expression of TGF-ß1, TGF-ßRI, Smad2, and collagen III and I increased in amputated bladder tissues, while Smad6 decreased over time. CONCLUSIONS: The main clinical features of pediatric neurogenic bladder (PNB) were detrusor paralysis and continuous intravesical pressure. Biological molecular findings are earlier than the pathophysiological findings. Therefore, early preventing bladder fibrosis by targeting TGF-ß1/Smad pathway-related proteins once knowing the PNB diagnosis might be an alternative treatment for PNB. IMPACT: The study found that the main clinical features of PNB were detrusor paralysis, continuous intravesical pressure, and increased TGF-beta/Smad signal proteins over time. The study makes contributions to the literature because it suggests biological molecular findings are earlier than the pathophysiological findings by various staining in PNB. The study investigated whole neurogenic bladder's progression changes, as well as the expression of TGF-ß1 fibrosis pathway-related proteins in the spinal nerve-injured PNB juvenile rat models, which suggests that early prevention of bladder fibrosis by targeting TGF-ß1/Smad pathway-related proteins once knowing the PNB diagnosis might be an alternative treatment for pediatric neurogenic bladder.

Engineered Stem Cells Improve Neurogenic Bladder by Overexpressing SDF-1 in a Pelvic Nerve Injury Rat Model.

There is still a lack of sufficient research on the mechanism behind neurogenic bladder (NB) treatment. The aim of this study was to explore the effect of overexpressed stromal cell-derived factor-1 (SDF-1) secreted by engineered immortalized mesenchymal stem cells (imMSCs) on the NB. In this study, primary bone marrow mesenchymal stem cells (BM-MSCs) were transfected into immortalized upregulated SDF-1-engineered BM-MSCs (imMSCs/eSDF-1+) or immortalized normal SDF-1-engineered BM-MSCs (imMSCs/eSDF-1-). NB rats induced by bilateral pelvic nerve (PN) transection were treated with imMSCs/eSDF-1+, imMSCs/eSDF-1-, or sham. After a 4-week treatment, the bladder function was assessed by cystometry and voiding pattern analysis. The PN and bladder tissues were evaluated via immunostaining and western blotting analysis. We found that imMSCs/eSDF-1+ expressed higher levels of SDF-1 in vitro and in vivo. The treatment of imMSCs/eSDF-1+ improved NB and evidently stimulated the recovery of bladder wall in NB rats. The recovery of injured nerve was more effective in the NB+imMSCs/eSDF-1+ group than in other groups. High SDF-1 expression improved the levels of vascular endothelial growth factor and basic fibroblast growth factor. Apoptosis was decreased after imMSCs injection, and was detected rarely in the NB+imMSCs/eSDF-1+ group. Injection of imMSCs boosted the expression of neuronal nitric oxide synthase, p-AKT, and p-ERK in the NB+imMSCs/eSDF-1+ group than in other groups. Our findings demonstrated that overexpression of SDF-1 induced additional MSC homing to the injured tissue, which improved the NB by accelerating the restoration of injured nerve in a rat model.

Intra-bladder wall transplantation of bone marrow mesenchymal stem cells improved urinary bladder dysfunction following spinal cord injury.

BACKGROUND: In the most of previous experiments, intrathecal administration of stem cells (SCs) was seen in the management of neurogenic bladder (NGB) following contusion or complete transaction in the rodent model of spinal cord injury (SCI). Here, we aimed to investigate whether intra bladder wall autologous bone marrow mesenchymal SC (BM-MSCs) transplantation, as a minimally invasive method, could improve bladder dysfunctions after a chronic phase of hemi- and complete-transection SCI in a female rat model. MATERIAL AND METHODS: A total of forty-two female Wistar rats were randomly divided into 6 groups (each in 7) and subjected to complete and incomplete spinal cord transection by a laminectomy at the T9 vertebral level. Four weeks after SCI operation, BM-MSCs (1 × 106/120 µl) were transplanted in six areas of the bladder muscle in rats with complete SCI (cSCI) and hemi SCI (hSCI) groups. In the rats from sham, cSCI and hSCI negative control groups, normal saline was injected instead of BM-MSCs. Four weeks post-cell transplantation, rats were subjected to conscious urodynamic for voiding function assessment. RESULTS: All bladders in cSCI and hSCI groups were the hyperreflexic type. The amplitude of uninhibited contraction in cSCI + BM-MSC group was decreased (p = 0.046). we noted that compliance was recovered in the hSCI + BM-MSCs group (p = 0.041). Residual volume was increased significantly after SCI while cell transplantation decreased this index in both hSCI and cSCI +BM-MSCs groups. The statistically significant result was only seen in the hSCI group (p = 0.046). Data showed that collagen deposition was markedly increased in the SCI group compared to the control or sham groups. These changes were decreased post-treatment in the hSCI group (p = 0.042). CONCLUSION: Our study added a notion that urinary dysfunction associated with SCI, was improved following direct injection of autologous BM-MSC transplantation to bladder wall in the chronic phase of SCI injury.

Electroacupuncture improves neurogenic bladder dysfunction through activation of NGF/TrkA signaling in a rat model.

OBJECTIVE: To observe the effect of electroacupuncture on the morphological change of the bladder tissue and the protein expression levels of NGF, TrkA, p-TrkA, AKT, and p-AKT in the bladder tissue of rats with neurogenic bladder after suprasacral spinal cord injury and to preliminarily explore its partial mechanism of action. METHODS: Eighty female Sprague-Dawley rats were randomly divided into blank group, model group, electroacupuncture group, model/siNGF group, and electroacupuncture/siNGF group according to random number table method with 16 rats in each group. Eighty Neurogenic bladder models after suprasacral spinal cord injury were established by adopting a modified spinal cord transection method. Electroacupuncture intervention was conducted on the 19th day after modeling. The bladder function was detected by bladder weight, urine output, serum BUN, and urine protein. After treatment for 7 consecutive days, the rats were killed and the bladder tissues were removed rapidly for microscopic observation of morphological change after hematoxylin and eosin stain and for determination of the protein expression levels of NGF, TrkA, p-TrkA, AKT, and p-AKT via Western blot analysis. The transcription of NGF was measured by reverse-transcription polymerase chain reaction. RESULTS: After treatment, compared with the blank group, the bladder weight of model and electroacupuncture groups were significantly increased (P < 0.05). Compared with the model group, the bladder weight of the electroacupuncture group was decreased (P > 0.05). Compared with the blank group, the urine output of the model group was increased ( P < 0.05). Compared with the blank group, the urine output of the electroacupuncture group was increased ( P > 0.05). Compared with the blank group, the serum BUN of the model group was increased ( P < 0.05). Compared with the blank group, the serum BUN of the electroacupuncture group was increased ( P > 0.05). Compared with the blank group, the urine protein of the model group was increased ( P < 0.05). Compared with the blank group, the urine protein of the electroacupuncture group was increased ( P > 0.05). The expression of NGF, p-TrkA, and p-AKT in the model and electroacupuncture groups was obviously higher than that in the blank group ( P < 0.05). The expression of NGF, p-TrkA, and p-AKT in the electroacupuncture group was higher than that in the model group. The expression of TrkA and AKT were unchanged in blank, model, and electroacupuncture groups ( P > 0.05). After tail vein injection with siNGF lentivirus, the expression of NGF in the model/siNGF group and electroacupuncture/siNGF group was significantly decreased ( P < 0.05). And the protein level of p-AKT and p-TrkA was significantly lower than that of the model and electroacupuncture groups ( P < 0.05). CONCLUSION: Sacral electroacupuncture therapy can improve the expression of both NGF/TrkA signaling and AKT signaling in the local nerve of the damaged spinal cord, inhibit apoptosis of the damaged spinal cord, protect nerve cells, and promote the recovery of the damaged nerve. At the same time, electroacupuncture can promote the coordination of micturition reflex and improve neurogenic bladder function after the spinal cord injury.

Involvement of interstitial cells of Cajal in bladder dysfunction in mice with experimental autoimmune encephalomyelitis.

BACKGROUND: Bladder dysfunction is an important symptom of experimental autoimmune encephalomyelitis (EAE). Our previous study showed that EAE-induced upregulation of the E-prostanoid receptor 3 (EP3) and E-prostanoid receptor 4 (EP4) in the bladder was accompanied by bladder dysfunction. Although many other studies have evaluated the lower urinary tract symptoms in multiple sclerosis, the mechanism remains unclear. OBJECTIVES: To investigate the effects of interstitial cells of Cajal (ICC) on bladder dysfunction in a novel neurogenic bladder model induced by experimental autoimmune encephalomyelitis. MATERIALS AND METHODS: The EAE model was induced by a previously established method, and bladder functions in mice were evaluated. Bladders were harvested for the analysis of ICCs and the genes associated with bladder mechanosensation including pannexin 1 (Panx1) and Gja1 (encoding connexin43) by immunofluorescence and western blotting. The stem cell factor cytokine (SCF) was intraperitoneally injected at the beginning of EAE onset. RESULTS: EAE mice developed profound bladder dysfunction characterized by significant urine retention, increased micturition and decreased urine output per micturition. EAE induced a significant decrease in c-Kit expression and ICCs number. EAE also induced a significant increase in pannexin 1 and connexin43. SCF treatment could ameliorate all of these pathological changes. CONCLUSIONS: ICCs and stem cell factor play an important role in EAE-induced bladder dysfunction, which may be used as therapeutic options in treating patients with multiple sclerosis-related bladder dysfunction.

Neurogenic bladder dysfunction does not correlate with astrocyte and microglia activation produced by graded force in a contusion-induced spinal cord injury.

Rodent models for the study of neurogenic bladder dysfunction after spinal cord injury (SCI) are difficult to standardize, particularly when evaluating the specific contribution of the SCI to end-organ function. The purpose of this study was to evaluate the degree of bladder dysfunction associated with a highly reproducible, contusion-induced SCI in female rats. An infinite horizon impactor was used to create a contusion SCI with a magnitude of either 100 or 150 kDyne at the T8/T9 thoracic region of female Sprague-Dawley rats. Locomotor function, and the presence of astrocytes (positive regions for Glial Fibrillary Acidic Protein) and microglia (positive cells for the integrin CD11b) at the SCI site were determined at four weeks after SCI. Similarly, cystometric properties were characterized in urethane anesthetized rats at four weeks post-SCI. The significant increases in astrocyte and microglia in the T8/T9 region in all of the SCI animals did not correlate with locomotor impairment or bladder dysfunction. After performing the cystometric studies substantial differences were found in both SCI groups when compared to intact animals, specifically a high frequency of non-voiding contractions, different durations for intraluminal pressure-high frequency oscillations, intercontractile intervals, impaired micturition volumes, and estimated voiding efficiency. These results suggest that a contusion SCI can increase microglia and astrocyte activation without a strong association with bladder dysfunction. The present study will be important for precise considerations about correlating the intensity of an SCI with impairment outcomes at both locomotor or organ function levels.

Effect of umbilical cord blood stem cells transplantation on bladder dysfunction induced by cerebral ischemia in rats.

OBJECTIVE: To demonstrate the effect of human umbilical cord blood-derived CD34+ cells on bladder dysfunction induced by cerebral ischemia in rats. MATERIALS AND METHODS: Female rats were subjected to either 60 minute middle cerebral artery occlusion (MCAO) or a sham operation. Rats were divided into four groups: sham operation, MCAO without treatment, infusion with 1×106 CD34+ cells 30 minutes before MCAO, and infusion with 1×106 CD34+ cells 3 hours after MCAO. Bladder function was analyzed by cystometry at 1 day, 3 days, and 7 days after MCAO. Expressions of nerve growth factor (NGF), M2 and M3 muscarinic receptors were measured by immunohistochemistry and real time polymerase chain reaction. RESULTS: Cystometric results showed that, following MCAO, rats have a significant increase in peak voiding pressure and residual volume. Conversely, there is a significant decrease in voided volumes and intercontraction intervals. Cystometric variables after pre- and postischemic CD34+ treatment nearly returned to levels found in sham-operated rats. The expression of bladder NGF and M3 was decreased after MCAO, but significantly increased following preischemic CD34+ treatment. There was decreased expression of bladder M2 mRNA despite an increased level of M2 immunoreactivity at 3 days and 7 days after MCAO. Expression of bladder M2 immunoreactivity and mRNA nearly returned to sham group levels after preischemic CD34+ treatment. CONCLUSION: Bladder dysfunction in a rat model caused by MCAO may be restored to normal micturition by treatment with human umbilical cord blood-derived CD34+ cells and may be related to the expressions of NGF, M2, and M3 in the bladder.

Clinical Efficacy and Changes of Urothelial Dysfunction after Repeated Detrusor Botulinum Toxin A Injections in Chronic Spinal Cord-Injured Bladder.

Chornic spinal cord injury (SCI) will induce bladder urothelium dysfunction. This study investigated the therapeutic effects on urothelial dysfunction after repeated detrusor injections of onabotulinumtoxinA (BoNT-A) in SCI patients with neurogenic detrusor overactivity (NDO). Twenty chronic suprasacral SCI patients with NDO were enrolled. The patients received 300 U BoNT-A injection into the detrusor every six months. The urothelium was assessed by cystoscopic biopsy at baseline and six months after each BoNT-A treatment. Immunofluorescence staining for urothelial dysfunction, including E-cadherin, zonula occludens-1 (ZO-1), tryptase for mast cell activity, and urothelial apoptosis were investigated. The outcome of urothelial dysfunction parameters after BoNT-A injection were compared between baseline and six months after each treatment. Repeated 300 U BoNT-A injections showed a sustained decrease of detrusor pressure compared with baseline. After three repeated BoNT-A detrusor injections, significantly greater distributions of E-cadherin (p = 0.042) and ZO-1 (p = 0.003) expressions, but no significant changes, of urothelial apoptosis and mast cell activation were found after repeated BoNT-A therapy. Urothelial dysfunction, such as adhesive and junction protein concentrations in SCI patients' bladders, recovered after three repeated cycles of BoNT-A treatment. The therapeutic effects sustained. However, urothelial inflammation and apoptosis after SCI were not significantly improved after three repeated BoNT-A injections.

Contractile effects and receptor analysis of adenosine-receptors in human detrusor muscle from stable and neuropathic bladders.

To measure the relative transcription of adenosine receptor subtypes and the contractile effects of adenosine and selective receptor-subtype ligands on detrusor smooth muscle from patients with neuropathic overactive (NDO) and stable bladders and also from guinea-pigs. Contractile function was measured at 37°C in vitro from detrusor smooth muscle strips. Contractions were elicited by superfusate agonists or by electrical field stimulation. Adenosine-receptor (A1, A2A, A2B, A3) transcription was measured by RT-PCR. Adenosine attenuated nerve-mediated responses with equivalent efficacy in human and guinea-pig tissue (pIC50 3.65-3.86); the action was more effective at low (1-8 Hz) compared to high (20-40 Hz) stimulation frequencies in human NDO and guinea-pig tissue. With guinea-pig detrusor the action of adenosine was mirrored by the A1/A2-agonist N-ethylcarboxamidoadenosine (NECA), partly abolished in turn by the A2B-selectve antagonist alloxazine, as well as the A1-selective agonist N6- cyclopentyladenosine (CPA). With detrusor from stable human bladders the effects of NECA and CPA were much smaller than that of adenosine. Adenosine also attenuated carbachol contractures, but mirrored by NECA (in turn blocked by alloxazine) only in guinea-pig tissue. Adenosine receptor subtype transcription was measured in human detrusor and was similar in both groups, except reduced A2A levels in overactive bladder. Suppression of the carbachol contracture in human detrusor is independent of A-receptor activation, in contrast to an A2B-dependent action with guinea-pig tissue. Adenosine also reduced nerve-mediated contractions, by an A1- dependent action suppressing ATP neurotransmitter action.

Promising Effects of a Novel EP2 and EP3 Receptor Dual Agonist, ONO-8055, on Neurogenic Underactive Bladder in a Rat Lumbar Canal Stenosis Model.

PURPOSE: We investigated whether the novel EP (prostaglandin E2) receptor agonist ONO-8055 would improve the lower urinary tract dysfunction of neurogenic underactive bladder in a rat lumbar spinal canal stenosis model. MATERIALS AND METHODS: First, we studied the agonistic effect of ONO-8055 on EP receptors in EP receptor expressing CHO (Chinese hamster ovary) cells using the increase in the intracellular calcium level and intracellular cAMP (cyclic adenosine monophosphate) production as indicators of receptor activation. The effects of ONO-8055 on bladder and urethral strips from normal rats were then investigated. Finally, the effects of ONO-8055 on bladder and urethral function in rats with lumbar spinal canal stenosis were evaluated by awake cystometry and intraurethral perfusion pressure, respectively. The effects of tamsulosin and distigmine on urethral pressure were also evaluated. RESULTS: ONO-8055 is a highly potent and selective agonist for EP2 and EP3 receptors on CHO cells. While this compound contracted bladder strips, it relaxed urethral strips. Awake cystometry showed that ONO-8055 significantly decreased bladder capacity, post-void residual urine and voiding pressure. Compared with vehicle, tamsulosin and ONO-8055 significantly decreased urethral pressure. CONCLUSIONS: ONO-8055 decreased post-void residual urine, probably by decreasing bladder capacity. The decrease in voiding pressure probably resulted from the lowered urethral pressure due to relaxation of the urethra. Thus, the novel EP2 and EP3 receptor dual agonist ONO-8055 has the potential to improve neurogenic underactive bladder.

The role of brain-derived neurotrophic factor (BDNF) in the development of neurogenic detrusor overactivity (NDO).

Neurogenic detrusor overactivity (NDO) is a well known consequence of spinal cord injury (SCI), recognizable after spinal shock, during which the bladder is areflexic. NDO emergence and maintenance depend on profound plastic changes of the spinal neuronal pathways regulating bladder function. It is well known that neurotrophins (NTs) are major regulators of such changes. NGF is the best-studied NT in the bladder and its role in NDO has already been established. Another very abundant neurotrophin is BDNF. Despite being shown that, acting at the spinal cord level, BDNF is a key mediator of bladder dysfunction and pain during cystitis, it is presently unclear if it is also important for NDO. This study aimed to clarify this issue. Results obtained pinpoint BDNF as an important regulator of NDO appearance and maintenance. Spinal BDNF expression increased in a time-dependent manner together with NDO emergence. In chronic SCI rats, BDNF sequestration improved bladder function, indicating that, at later stages, BDNF contributes NDO maintenance. During spinal shock, BDNF sequestration resulted in early development of bladder hyperactivity, accompanied by increased axonal growth of calcitonin gene-related peptide-labeled fibers in the dorsal horn. Chronic BDNF administration inhibited the emergence of NDO, together with reduction of axonal growth, suggesting that BDNF may have a crucial role in bladder function after SCI via inhibition of neuronal sprouting. These findings highlight the role of BDNF in NDO and may provide a significant contribution to create more efficient therapies to manage SCI patients.

γEpithelial Na(+) Channel (γENaC) and the Acid-Sensing Ion Channel 1 (ASIC1) expression in the urothelium of patients with neurogenic detrusor overactivity.

OBJECTIVE: To investigate the expression of two types of cation channels, γEpithelial Na(+) Channel (γENaC) and the Acid-Sensing Ion Channel 1 (ASIC1), in the urothelium of controls and in patients affected by neurogenic detrusor overactivity (NDO). In parallel, urodynamic parameters were collected and correlated to the immunohistochemical results. PATIENTS SUBJECTS AND METHODS: Four controls and 12 patients with a clinical diagnosis of NDO and suprasacral spinal cord lesion underwent urodynamic measurements and cystoscopy. Cold-cup biopsies were frozen and processed for immunohistochemistry and Western Blot. Spearman's correlation coefficient between morphological and urodynamic data was applied. One-way anova followed by Newman-Keuls multiple comparison post hoc test was applied for Western Blot results. RESULTS: In the controls, γENaC and ASIC1 were expressed in the urothelium with differences in their cell distribution and intensity. In patients with NDO, both markers showed consistent changes either in cell distribution and labelling intensity compared with the controls. A significant correlation between a higher intensity of γENaC expression in the urothelium of patients with NDO and lower values of bladder compliance was detected. CONCLUSIONS: The present findings show important changes in the expression of γENaC and ASIC1 in NDO human urothelium. Notably, while the changes in γENaC might impair the mechanosensory function of the urothelium, the increase of ASIC1 might represent an attempt to compensate for the excess in local sensitivity.

Intravesical TRPV4 blockade reduces repeated variate stress-induced bladder dysfunction by increasing bladder capacity and decreasing voiding frequency in male rats.

Individuals with functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) often report symptom (e.g., urinary frequency) worsening due to stress. One member of the transient receptor potential ion channel vanilloid family, TRPV4, has recently been implicated in urinary bladder dysfunction disorders including OAB and IC/BPS. These studies address the role of TRPV4 in stress-induced bladder dysfunction using an animal model of stress in male rats. To induce stress, rats were exposed to 7 days of repeated variate stress (RVS). Quantitative PCR data demonstrated significant (P ≤ 0.01) increases in TRPV4 transcript levels in urothelium but not detrusor smooth muscle. Western blot analyses of split urinary bladders (i.e., urothelium and detrusor) showed significant (P ≤ 0.01) increases in TRPV4 protein expression levels in urothelial tissues but not detrusor smooth muscle. We previously showed that RVS produces bladder dysfunction characterized by decreased bladder capacity and increased voiding frequency. The functional role of TRPV4 in RVS-induced bladder dysfunction was evaluated using continuous, open outlet intravesical infusion of saline in conjunction with administration of a TRPV4 agonist, GSK1016790A (3 µM), a TRPV4 antagonist, HC067047 (1 µM), or vehicle (0.1% DMSO in saline) in control and RVS-treated rats. Bladder capacity, void volume, and intercontraction interval significantly decreased following intravesical instillation of GSK1016790A in control rats and significantly (P ≤ 0.01) increased following administration of HC067047 in RVS-treated rats. These results demonstrate increased TRPV4 expression in the urothelium following RVS and that TRPV4 blockade ameliorates RVS-induced bladder dysfunction consistent with the role of TRPV4 as a promising target for bladder function disorders.

Purinergic signalling in the urinary tract in health and disease.

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Involvement of connexins 43 and 45 in functional mechanism of human detrusor overactivity in neurogenic bladder.

OBJECTIVE: To assess the involvement of connexins (Cxs) 43 and 45 in the selective inhibition of detrusor contractions in patients with neurogenic detrusor overactivity (NDO). MATERIALS AND METHODS: Detrusor strips with and without mucosa were obtained from patients undergoing cystectomy for either neurogenic bladder with NDO refractory to pharmacologic treatment or bladder cancer with no overactive bladder symptoms (ie, control group). The strips were isometrically mounted in organ baths. The effects of the selective inhibitors Cxs 43 and 45 on carbachol-induced contractions of bladder strips were assessed. RESULTS: Overall, 47 patients with a median age of 61 years (range 19-83) were included. The female-to-male ratio was 0.42. Selective inhibitors of Cxs 43 and 45 significantly inhibited carbachol-induced contractions of bladder strips from patient with NDO (P <.01) but had no effect in the control group. When tested without mucosa, the effect of the Cx 43 inhibitor in the NDO patient strips was abolished, but it remained unchanged with the Cx 45 inhibitor (P <.05). CONCLUSION: The pharmacologic modulation of Cx-mediated intercellular communication, targeting Cxs 43 and 45, is directly involved in the functional mechanism of NDO and might represent a future target for the treatment of NDO.

Lack of transient receptor potential vanilloid 1 channel modulates the development of neurogenic bladder dysfunction induced by cross-sensitization in afferent pathways.

BACKGROUND: Bladder pain of unknown etiology has been associated with co-morbid conditions and functional abnormalities in neighboring pelvic organs. Mechanisms underlying pain co-morbidities include cross-sensitization, which occurs predominantly via convergent neural pathways connecting distinct pelvic organs. Our previous results showed that colonic inflammation caused detrusor instability via activation of transient receptor potential vanilloid 1 (TRPV1) signaling pathways, therefore, we aimed to determine whether neurogenic bladder dysfunction can develop in the absence of TRPV1 receptors. METHODS: Adult male C57BL/6 wild-type (WT) and TRPV1-/- (knockout) mice were used in this study. Colonic inflammation was induced by intracolonic trinitrobenzene sulfonic acid (TNBS). The effects of transient colitis on abdominal sensitivity and function of the urinary bladder were evaluated by cystometry, contractility and relaxation of detrusor smooth muscle (DSM) in vitro to various stimuli, gene and protein expression of voltage-gated sodium channels in bladder sensory neurons, and pelvic responses to mechanical stimulation. RESULTS: Knockout of TRPV1 gene did not eliminate the development of cross-sensitization between the colon and urinary bladder. However, TRPV1-/- mice had prolonged intermicturition interval and increased number of non-voiding contractions at baseline followed by reduced urodynamic responses during active colitis. Contractility of DSM was up-regulated in response to KCl in TRPV1-/- mice with inflamed colon. Application of Rho-kinase inhibitor caused relaxation of DSM in WT but not in TRPV1-/- mice during colonic inflammation. TRPV1-/- mice demonstrated blunted effects of TNBS-induced colitis on expression and function of voltage-gated sodium channels in bladder sensory neurons, and delayed development of abdominal hypersensitivity upon colon-bladder cross-talk in genetically modified animals. CONCLUSIONS: The lack of TRPV1 receptors does not eliminate the development of cross-sensitization in the pelvis. However, the function of the urinary bladder significantly differs between WT and TRPV-/- mice especially upon development of colon-bladder cross-sensitization induced by transient colitis. Our results suggest that TRPV1 pathways may participate in the development of chronic pelvic pain co-morbidities in humans.

[Observation of neuropeptides in bladder after spinal cord injury in rats].

OBJECTIVE: To observe the altered expressions of neuropeptide Y, substance P and vasoactive intestinal peptide in detrusor of SD rats after spinal cord injury and explore the relationship of the above neuropeptides and neurogenic bladder after spine cord injury. METHODS: Twenty male clean-grade SD rats, aged 6 weeks, were selected and randomized into spinal cord injury group (n = 10) and control group (n = 10). Rats in spinal cord injury group were smashed at T10 to cause spinal cord incomplete injury model by the weight drop method while laminectomy alone without smashing was administered in control group. At Week 1 post-operation, all rats were assessed by the maximum bladder capacity, bladder compliance and detrusor pressure for the confirmation of spastic bladder. And all detrusor specimens were marked with argentation and immunohistochemistry for the analyses of nerve fibers, neuropeptide Y, substance P and vasoactive intestinal peptide. The results were evaluated with semiquantitative method to observe the contents of nerve fiber and neuropeptides. RESULTS: At Week 1 post-operation, the mean maximum bladder compactly, mean maximum detrusor pressure and mean compliance in SCI rats was 0.71 ± 0.24 ml, 32.27 ± 3.12 cm H2O and 0.020 ± 0.009 ml/cm H2O versus 2.0 ± 0.4 ml, 21.0 ± 3.0 cm H2O and 0.090 ± 0.020 ml/cm H2O in normal control group respectively. And the differences were statistically significant (P < 0.01). Meanwhile, the mean content of nerve fibers of neurogenic bladder decreased markedly than that of normal control group (2.58 ± 0.13 vs 5.65 ± 0.26). As compared with the normal control group, the expressions of neuropeptide Y, substance P and vasoactive intestinal peptide (mean integrated optical density: 3.2 ± 0.5, 1.7 ± 0.4 and 2.1 ± 0.4 respectively) decreased dramatically in SCI rats. And the differences were statistically significant (P < 0.01). CONCLUSION: The number of nerve fibers and the content of neuropeptides significantly decrease in neurogenic bladder after spinal cord injury in rats. The reduction of neuropeptides may be correlated with the formation of neurogenic bladder after spinal cord injury.