Protective Effect of a Rho-kinase Inhibitor on Bladder Dysfunction in a Rat Model of Chronic Bladder Ischemia.

OBJECTIVE: To investigate the effect of fasudil, a Rho-kinase inhibitor, on chronic ischemia-related bladder dysfunction. MATERIALS AND METHODS: Male Sprague-Dawley rats (16 weeks old) were divided into control, chronic bladder ischemia (CBI), and CBI with fasudil treatment (CBI-Fa) groups. The CBI and CBI-Fa groups underwent balloon endothelial injury of bilateral iliac arteries and received a 2% cholesterol diet for 8 weeks after the procedure to induce CBI. The CBI-Fa group was given oral fasudil (30 mg/kg/day) using zonde for 8 weeks after the procedure. The control group received a regular diet for 8 weeks. After cystometry in a conscious state, rats from each group were euthanized, and the bladders and common iliac arteries were harvested for pharmacologic and histologic examination. RESULTS: Mean wall thickness of the common iliac arteries was significantly greater in the CBI group than in controls. Contractile responses of muscle strips were significantly lower in CBI group rats than in controls. In the CBI group, micturition interval was significantly shorter, and bladder capacity was significantly lower compared with those in controls. In the CBI-Fa group, arterial wall thickening was significantly suppressed compared with the CBI group. Significant improvements in muscle strip contractility and cystometric parameters were seen in the CBI-Fa group compared with the CBI group. CONCLUSION: Our results suggest that chronic treatment with fasudil could prevent neointimal formation in arteries and bladder dysfunction in this rat model. Fasudil may be therapeutically useful in protecting bladder function in chronically ischemic bladders.

Silodosin, an α(1A)-Adrenoceptor Antagonist, May Ameliorate Ischemia-Induced Bladder Denervation and Detrusor Dysfunction by Improving Bladder Blood Flow.

BACKGROUND/AIMS: This study was performed to investigate the detailed mechanism underlying the effects of the selective α(1A)-adrenoceptor antagonist, silodosin, on bladder function in a rat model of atherosclerosis-induced chronic bladder ischemia (CBI). METHODS: The CBI model was prepared by balloon endothelial injury of the bilateral iliac arteries in male rats. Using an osmotic pump, the CBI rats received either silodosin or vehicle alone subcutaneously for 8 weeks. Rats received a 2% cholesterol diet throughout the experiment. Bladder blood flow (BBF) was measured. Immunohistochemical staining was performed to determine the nerve distribution and nerve growth factor expression in the bladder. Bladders were used for muscle strip contraction analysis. The expression levels of muscarinic M2 and M3 receptors were measured. RESULTS: Silodosin abrogated the decrease in BBF in CBI rats. Silodosin prevented the decrease in nerve distribution and increase in nerve growth factor expression in the CBI model. Bladder contractile response was reduced in the CBI group. Silodosin ameliorated the effect on the bladder contractile response. The level of muscarinic M3 receptor mRNA present in the bladder of CBI rats was increased by silodosin. CONCLUSION: The results of this study suggest that silodosin ameliorates the denervation of the bladder and effects on detrusor contractile function under ischemic conditions by restoring BBF.

Melatonin Improves Erectile Function in Rats With Chronic Lower Body Ischemia.

INTRODUCTION: Arterial occlusive disease is the leading cause of erectile dysfunction (ED). Using an established rat model we wanted to characterize the changes caused by atherosclerosis-induced chronic ischemia on penile structures and erectile function. AIM: To investigate the effect of melatonin on these parameters. METHODS: Adult male Sprague-Dawley rats were divided into control, arterial injury (AI) and AI with melatonin treatment groups. AI and AI-melatonin groups underwent endothelial injury of the iliac arteries and received a 2% cholesterol diet following AI surgery for 8 weeks. AI-melatonin group rats received melatonin (20 mg/kg/day) orally for 8 weeks after AI. The control group received a regular diet. After 8 weeks, erectile function was tested. Corpus cavernosum (CC) tissues were processed for pharmacological and immunohistochemical studies, histological examination, and Western blotting. MAIN OUTCOME MEASURES: Apomorphine test was performed to evaluate erectile function. Organ bath study was performed to measure the CC-contraction induced by KCl and phenylephrine, and relaxation induced by electrical field stimulation (EFS) and sodium nitroprusside (SNP). RESULTS: The number of erectile responses was significantly lower in the AI group (2.5 ± 0.5/hour) than in the control (5.0 ± 0.7/hour) and in the melatonin-treated groups (5.0 ± 0.3/hour). The responses to phenylephrine were lower in the AI-groups than in the controls, but there were no differences between control and AI-melatonin groups. SNP-induced relaxation in the AI-melatonin group was higher than in the AI, but lower than in control group. The EFS-elicited relaxation responses in the AI group were significantly lower than in the control and AI-melatonin groups. Compared to controls, CC tissues from the AI group showed significantly higher collagen content, and lower protein expression of eNOS and nNOS, and increased expression of iNOS. These changes were reduced or prevented by melatonin treatment. CONCLUSION: Treatment with melatonin reduced/prevented functional and morphological changes induced by chronic ischemia on penile structure and function.

Preventive Effect of Hydrogen Water on the Development of Detrusor Overactivity in a Rat Model of Bladder Outlet Obstruction.

PURPOSE: Bladder ischemia and oxidative stress contribute to the pathogenesis of bladder dysfunction caused by bladder outlet obstruction. H2 reportedly acts as an effective antioxidant. We investigated whether oral ingestion of H2 water would have a beneficial effect on bladder function in a rat model of bladder outlet obstruction. MATERIALS AND METHODS: H2 water was made by dissolving H2 gas in ordinary drinking water using a hydrogen water producing apparatus. The bladder outlet obstruction model was surgically induced in male rats. Rats with obstruction were fed H2 water or ordinary drinking water. On week 4 postoperatively cystometry was performed. Oxidative stress markers and the bladder nerve growth factor level were determined. Bladder tissues were processed for pharmacological studies and histological analysis. RESULTS: The micturition interval and micturition volume significantly decreased in obstructed rats given ordinary drinking water. These decreases were significantly suppressed by oral ingestion of H2 water. Increased post-void residual volume in obstructed rats was significantly reduced by H2 water. Obstruction led to a significant increase in bladder weight, oxidative stress markers and nerve growth factor. H2 water significantly suppressed these increases without affecting bladder weight. There was no significant difference in histological findings between rats with bladder obstruction given H2 water and ordinary drinking water. Decreased responses of detrusor muscle strips from obstructed bladders to KCl, carbachol and electrical field stimulation were reversed by H2 water ingestion. CONCLUSIONS: Results suggest that H2 water could ameliorate bladder dysfunction secondary to bladder outlet obstruction by attenuating oxidative stress.

Chronic Pelvic Ischemia: Contribution to the Pathogenesis of Lower Urinary Tract Symptoms (LUTS): A New Target for Pharmacological Treatment?

The incidence of lower urinary tract symptoms, including overactive bladder (OAB), is continuing to rise, and is associated with a negative impact on quality of life and a heavy economic burden. A major risk factor for OAB is advancing age. The etiology of OAB is multifactorial and appears to involve myogenic, neurogenic, and urotheliogenic factors. In this article, we review the strengthening preclinical evidence supporting the contribution of chronic pelvic ischemia to the pathogenesis of OAB. In animal models, chronic ischemia induced by arterial injury and a high-fat diet upregulates markers of oxidative stress and proinflammatory cytokines in the urothelium and lamina propria, and leads to increased expression of nerve growth factor. These processes result in increased afferent activity and an increased frequency of micturition, reflecting a state of bladder hyperactivity. In severe, prolonged cases, bladder overactivity may develop into underactivity. Antimuscarinic therapies are the mainstay of OAB treatment, but their usefulness is limited by modest efficacy and troublesome side-effects. Our increasing understanding of the contribution of chronic ischemia to OAB is leading toward novel therapeutic options targeting chronic pelvic ischemia and its morphological, functional, and oxidative consequences. Preclinical trials have demonstrated encouraging results with α1 -adrenoreceptor blockade, phosphodiesterase type 5 inhibition, ß3 -adrenoreceptor agonism, free radical scavenging, and stem cell therapy, in preventing morphological, biochemical and functional changes induced by chronic bladder ischemia.

Possible effect of lysophosphatidic acid on cell proliferation and involvement of lysophosphatidic acid and lysophosphatidic acid receptors in mechanical stretch-induced mitogen-activated protein kinase.

OBJECTIVES: To determine whether lysophosphatidic acid activates the mitogen-activated protein kinase and increases DNA synthesis in human bladder smooth muscle cells, and to examine the involvement of lysophosphatidic acid and lysophosphatidic acid receptor in mechanical stretch-induced mitogen-activated protein kinase activation in cultured human bladder smooth muscle cells. METHODS: TaqMan reverse transcription polymerase chain reaction was used to determine the mRNA expression levels of six lysophosphatidic acid receptor subtypes. Mitogen-activated protein kinase activity enhanced by either lysophosphatidic acid or mechanical stretch was measured by western blotting. The effect of lysophosphatidic acid on DNA synthesis was assessed by 5-bromo-2'-deoxy-uridine incorporation assay. RESULTS: Lysophosphatidic acid 1 subtype mRNA was predominantly expressed (96%). Lysophosphatidic acid activated the mitogen-activated protein kinase in a concentration-dependent manner. C-jun NH2 -terminal kinase showed the highest activity among the three subsets of the mitogen-activated protein kinase family members (c-jun NH2 -terminal kinase, extracellular signal-regulated kinases, p38). Lysophosphatidic acid also increased incorporation of 5-bromo-2'-deoxy-uridine. These responses were suppressed by Ki16425 (lysophosphatidic acid receptor antagonist). Mechanical stretch mainly induced c-jun NH2 -terminal kinase activation. This activation was partially inhibited by Ki16425. CONCLUSIONS: Lysophosphatidic acid might activate the c-jun NH2 -terminal kinase component of the mitogen-activated protein kinase family and DNA synthesis through lysophosphatidic acid receptors (presumably, through lysophosphatidic acid 1) in human bladder smooth muscle cells. The present study also implicates the involvement of lysophosphatidic acid and lysophosphatidic acid receptors in mechanical stretch-induced c-jun NH2 -terminal kinase activation. Lysophosphatidic acid receptor can be partially activated by mechanical stretching through lysophosphatidic acid-dependent or independent mechanism.

Pelvic arterial occlusive disease affects the RhoA/Rho-kinase pathway in bladder smooth muscle.

PURPOSE: We investigated the effect of pelvic arterial occlusive disease on the RhoA/Rho-kinase pathway in a rat model of chronic bladder ischemia. MATERIALS AND METHODS: Male adult Sprague Dawley® rats at age 16 weeks were divided into arterial endothelial injury and control groups. The injury group underwent balloon endothelial injury of the bilateral iliac arteries and received a 2% cholesterol diet to induce pelvic arterial occlusive disease. The control group received a regular diet. At 8 weeks cystometrograms were performed. Bladder tissue was harvested for pharmacological studies and Western blot. RESULTS: Cystometrograms showed significantly lower bladder capacity in the arterial endothelial injury group than in controls. Organ bath studies revealed significantly decreased phasic contractions induced by carbachol in bladder strips from the injury group than from controls. In controls bladder strip tonic contractions induced by carbachol were significantly decreased compared with phasic contractions. However, no significant difference was observed between phasic and tonic contractions in the injury group. The Rho-kinase inhibitor Y-27632 produced a concentration dependent decrease in tonic contractions, which was more pronounced in the injury group. Western blot showed significantly increased RhoA and Rho-kinase ß expression in the injury group. CONCLUSIONS: Our results suggest that pelvic arterial occlusive disease can affect the RhoA/Rho-kinase pathway in the bladder. This pathway might possibly be involved in the maintenance of tonic contraction and contribute to the bladder hyperactivity caused by pelvic arterial occlusive disease.

Chronic bladder ischemia and oxidative stress: new pharmacotherapeutic targets for lower urinary tract symptoms.

Chronic bladder ischemia is potentially a common cause of lower urinary tract symptoms in the elderly. Epidemiological studies have shown a close association between lower urinary tract symptoms and vascular risk factors for atherosclerosis, and investigations using transrectal color Doppler ultrasonography have shown a negative correlation between decreased lower urinary tract perfusion and International Prostate Symptom Score in elderly patients with lower urinary tract symptoms. Bladder blood flow is also known to decrease in men with bladder outlet obstruction as a result of benign prostatic hyperplasia. Studies in animal models suggest that chronic bladder ischemia and repeated ischemia/reperfusion during a micturition cycle might produce oxidative stress, leading to denervation of the bladder and the expression of tissue-damaging molecules in the bladder wall, which could be responsible for the development of bladder hyperactivity progressing to bladder underactivity. The effects of drugs with different mechanisms of action; for example, α1-adrenoceptor antagonists, phosphodiesterase type 5 inhibitors, free radical scavengers and ß3-adrenoceptor agonist, have been studied in animal models of chronic bladder ischemia. The drugs, representing different treatment principles for increasing blood flow and decreasing oxidative stress, showed protective effects not only on urodynamic parameters, but also on negative effects on muscle contractility and on detrimental structural bladder wall changes. Improvement of lower urinary tract perfusion and control of oxidative stress can be considered new therapeutic strategies for treatment of bladder dysfunction induced by chronic ischemia.

Urinary bladder mucosal responses to ischemia.

PURPOSE: The objectives of this study were to examine the expression of various cellular proteins within the urothelium (UT) and lamina propria (LP) following chronic bladder ischemia in the rat urinary bladder. MATERIALS AND METHODS: Urinary bladders were removed from adult Sprague-Dawley rats 8 weeks after creation of bladder ischemia and from sham controls. Immunocytochemistry was used to examine distribution of LP-vimentin-immunoreactive (IR) cells and connexins (Cx26; Cx43), and western immunoblotting or ELISA for proteins involved in UT barrier and sensory functions. RESULTS: Ischemia was associated with a significant increase in LP-vimentin-IR cells and increased expression of the gap junction proteins Cx26 and Cx43 within the bladder UT as compared to sham control. Ischemia also resulted in an increased (p < 0.05) expression level of the junctional marker (ZO-1) and non-significantly increased expressions of the trophic factor nerve growth factor as well as norepinephrine. CONCLUSIONS: Our findings reveal that chronic ischemia alters a number of proteins within the UT and underlying LP. These proteins are involved in barrier function, remodeling, repair as well as intercellular communication. The increased expression of LP-vimentin-IR cells suggests that changes in cell-cell interactions could play a role in ischemia-induced changes in bladder activity.

Protective effect of tadalafil on the functional and structural changes of the rat ventral prostate caused by chronic pelvic ischemia.

BACKGROUND: The etiology of Benign Prostatic Hyperplasia (BPH), a common among aged men, is not fully understood, however, in addition to androgens and aging, chronic ischemia has been proposed to contribute. Using an established rat model, we investigated whether chronic ischemia alters the structural and functional properties of the ventral rat prostate, and whether phosphodiesterase type 5 (PDE5) inhibitor (tadalafil) may have a protective action. METHODS: Adult male Sprague-Dawley rats were divided into control, arterial endothelial injury (AI), and AI with tadalafil treatment (AI-tadalafil) groups. AI and AI-tadalafil groups underwent endothelial injury of the iliac arteries and received a 2% cholesterol diet following AI. AI-tadalafil rats were treated with tadalafil (2 mg/kg/day) orally for 8 weeks after AI. The control group received a regular diet. After 8 weeks, animals were sacrificed, and pharmacological and morphological studies on prostate tissues were performed. RESULTS: Iliac arteries from AI rats displayed neo-intimal formation and luminal occlusion, an effect that was not prevented by tadalafil treatment. In the AI group, there was an obvious epithelial atrophy and a statistically significant increase in collagen fibers compared with the controls. Immunohistochemically, there was an up-regulation of smooth muscle α-actin (SMA). Contractile responses of prostate strips to KCl, electrical field stimulation (EFS), and phenylephrine (PE) were significantly higher after AI than in controls. Chronic treatment with tadalafil prevented the increase in contractile responses in ischemic tissue, and decreased the collagen deposition compared with the AI group. CONCLUSIONS: In this rat model, chronic pelvic ischemia caused distinct functional and morphological changes in the prostate. Prostatic tissue from ischemic animals showed an increased contractile response to electrical and pharmacological stimulation, an increase in SMA, and an increased deposition of collagen. All these changes could be prevented by treatment with the PDE5 inhibitor, tadalafil, suggesting an involvement of cyclic guanosine monophosphate (cGMP).

Pharmacological treatment of chronic pelvic ischemia.

Epidemiological studies have shown that lower urinary tract symptoms, including overactive bladder, commonly occur in both men and women, with an age-related increase in both sexes. Vascular endothelial dysfunction and urological symptoms are common in the metabolic syndrome; they also occur during the human ageing process and are independent risk factors for the development of atherosclerosis and hypertension. Pelvic arterial insufficiency may lead to impaired lower urinary tract perfusion and play an important role in the development of bladder dysfunction such as detrusor overactivity and overactive bladder. It seems reasonable, but has not been definitely established clinically, that chronic ischemia-related bladder dysfunction will progress to bladder underactivity. Studies in experimental models in rabbits and rats have shown that pelvic arterial insufficiency may result in significant bladder ischemia with reduced bladder wall oxygen tension, oxidative stress, increased muscarinic receptor activity, ultrastructural damage, and neurodegeneration. Several types of drug may be able to prevent some of these changes. Even if the α1-adrenoceptor blocker, silodosin, the phosphodiesterase type 5 inhibitor, tadalafil, the ß3-α1-adrenoceptor agonist, mirabegron, and the free radical scavenger, melatonin, were unable to prevent the development of neointimal hyperplasia and consequent luminal occlusion in animal models, they all exerted a protecting effect on urodynamic parameters, and on the functional and morphological changes of the bladder demonstrable in vitro. The different mechanisms of action of the drugs suggest that many factors are involved in the pathogenesis of chronic ischemia-induced bladder dysfunction and can be targets for intervention. Since several of the agents tested are used clinically and effectively for relieving lower urinary tract symptoms, the results from animal models of chronic bladder ischemia seem to have translational value. Animal models may be of relevance for designing clinical studies to demonstrate if a certain drug may prevent progression of ischemia-related functional and morphological bladder changes.

Effects of allogeneic bone marrow derived mesenchymal stromal cell therapy on voiding function in a rat model of Parkinson disease.

PURPOSE: Cellular therapy induced transient urodynamic improvement in a rat model of Parkinson disease in which bladder dysfunction was noted after unilateral injection of 6-hydroxydopamine into the medial forebrain bundle. We sought to prolong the effect by injecting allogeneic rat bone marrow mesenchymal stromal cells before and after microencapsulation into the substantia nigra pars compacta. MATERIALS AND METHODS: Female rats underwent unilateral stereotactic injection of 6-hydroxydopamine in the medial forebrain bundle. Injection was performed in the ipsilateral substantia nigra pars compacta using vehicle alone or vehicle with nonmicroencapsulated or microencapsulated rat bone marrow derived mesenchymal stromal cells. Rats were evaluated by cystometry 7, 14, 28 and 42 days after treatment. Brains were extracted for immunostaining. RESULTS: At 42 days the nonmicroencapsulated group had lower threshold and intermicturition pressure, spontaneous activity and AUC than vehicle treated animals. Rats that received microencapsulated cells had lower threshold pressure at 28 days and lower spontaneous activity at 42 days than vehicle treated rats. Microencapsulated and nonmicroencapsulated rat bone marrow derived mesenchymal stromal cells were noted in the substantia nigra pars compacta up to 42 days after transplantation. At 42 days tyrosine hydroxylase positive neurons were more numerous in the substantia nigra pars compacta of the nonmicroencapsulated group, followed by the microencapsulated and vehicle treated groups. CONCLUSIONS: Urodynamic effects of the 6-hydroxydopamine lesion persisted up to 42 days after vehicle injection. Transplantation of nonmicroencapsulated rat bone marrow derived mesenchymal stromal cells improved urodynamic pressure by 42 days after treatment more markedly than microencapsulated cells. This was associated with more tyrosine hydroxylase positive neurons in the treated substantia nigra pars compacta of the nonmicroencapsulated group, suggesting that functional improvement requires a juxtacrine effect.

Progressive vascular damage may lead to bladder underactivity in rats.

PURPOSE: We assessed whether progressive vascular damage causes bladder underactivity in rats. MATERIALS AND METHODS: Adult male Sprague Dawley® rats were divided into 4 groups. Controls received a regular diet and tap water. The L-NAME group received a 2% cholesterol diet and L-NAME (3 mg/ml) dissolved in drinking water. The arterial injury group underwent balloon endothelial injury of the common iliac arteries and received a 2% cholesterol diet and tap water after injury. The arterial injury/L-NAME group also received L-NAME dissolved in drinking water. At 8 weeks urodynamics were performed, bladder tissue was harvested for pharmacological studies, and the iliac arteries and bladders were histologically examined. RESULTS: Iliac arteries from the injury and injury/L-NAME groups showed neointimal formation and luminal occlusion but arteries from the L-NAME group did not. In the L-NAME and injury groups bladder capacity and voided volume were less than in controls. Conversely, in the injury/L-NAME group these cystometric parameters were significantly greater than in the other groups. Post-void residual volume in the injury/L-NAME group tended to increase compared with the other groups. Contractile responses of bladder strips to various stimuli in the L-NAME, injury and injury/L-NAME groups were significantly less than in controls and the lowest in the injury/L-NAME group. The injury and injury/L-NAME groups showed a significantly increased percent of collagen compared to controls. CONCLUSIONS: Pelvic arterial occlusive disease plus vascular endothelial dysfunction may cause progressive vascular damage resulting in bladder dysfunction that develops from bladder hyperactivity to bladder underactivity.

The presence of antibodies against the AD2 epitope of cytomegalovirus glycoprotein B is associated with acute rejection after renal transplantation.

The aim of this study was to evaluate the association between antibodies against cytomegalovirus (CMV) glycoprotein B (gB) and acute rejection after transplantation. Seventy-seven consecutive renal transplant recipients in a D + /R+ setting were studied. Biopsy-proven rejection occurred in 35% of the recipients. Among these recipients, 85% had antibodies against CMV gB. The rate of acute rejection was significantly higher in recipients with antibodies against gB than in those without them. Antibodies against gB can be a useful predictor of acute rejection in renal transplant recipients in a D + /R+ setting.

Association between polymorphism of beta3-adrenoceptor gene and overactive bladder.

AIMS: In human urinary bladder, beta3-ARs play an important role in promoting detrusor relaxation during the storage phase of the micturition cycle. The present study investigated whether a Trp64Arg polymorphism of the gene encoding the beta3-AR is associated with overactive bladder (OAB) syndrome. METHODS: This study involved 100 women with OAB and 101 healthy control women without OAB. Hair root samples were obtained from all subjects and used for beta3-AR gene analysis. Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis was performed to analyze a polymorphism in the gene of Trp64Arg. RESULTS: The overall frequency of the 64Arg variant (heterozygous plus homozygous) in OAB patients was 47% and significantly higher than the frequency of 22.8% found in non-OAB control women. Within OAB patients, numbers of micturitions per day, urgency episodes per day, and urgency incontinence episodes per day in the 64Arg variant carriers were not significantly different from those in the normal gene carriers. CONCLUSIONS: This study shows that the Trp64Arg polymorphism in the beta3-AR gene is weakly but significantly associated with OAB syndrome.

Functional consequences of chronic bladder ischemia.

The pathophysiology of lower urinary tract symptoms (LUTS), particularly in the elderly, seems to be multifactorial. One of the factors involved may be chronic ischemia of the bladder caused by bladder outflow obstruction (male) or atherosclerosis (male/female). The mechanisms by which chronic ischemia initiates and causes LUTS and progressive bladder dysfunction, and the time course of the effects, are incompletely known. Bladder ischemia and repeated ischemia/reperfusion during a micturition cycle may produce oxidative stress, leading to denervation of the bladder and the expression of tissue damaging molecules in the bladder wall. This may be responsible for the development of detrusor overactivity progressing to detrusor underactivity and inability to empty the bladder. The extent of bladder dysfunction in chronic bladder ischemia may depend on the degree and duration of ischemia. To prevent chronic bladder ischemia caused by atherosclerosis and to treat its consequences, more pathophysiological knowledge is needed. Several animal models of atherosclerosis-induced chronic bladder ischemia are available and should be useful tools for further research.

Protective effect of a ß3-adrenoceptor agonist on bladder function in a rat model of chronic bladder ischemia.

BACKGROUND: The ß3-adrenoceptor (AR) agonist mirabegron has been introduced as a treatment for the overactive bladder. Its effects on the function of the ischemic bladder are not known. OBJECTIVE: To investigate the effect of mirabegron in a rat model of chronic ischemia-related bladder dysfunction. DESIGN, SETTING, AND PARTICIPANTS: Male Sprague-Dawley rats were divided into three groups: control (n=10), arterial endothelial injury (AI; n=16), and AI with mirabegron treatment (AI-mirabegron; n=10). AI and AI-mirabegron groups underwent endothelial injury of the iliac arteries and received a 2% cholesterol diet following AI. AI-mirabegron rats received mirabegron (10mg/kg/d) orally for 8 wk. The control group received a regular diet. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: After 8 wk, urodynamic investigation was performed in awake animals. Pharmacologic in vitro studies and histologic examination of the iliac arteries and bladders were performed. RESULTS AND LIMITATIONS: Iliac arteries from both AI and AI-mirabegron rats displayed neointimal formation and luminal occlusion. Micturition interval (MI), bladder capacity (Bcap), and voided volume (VV) in the AI group were significantly less than in the control group (p<0.01). In the AI-mirabegron group, MI, Bcap, and VV were significantly larger than in the AI group (p<0.05) but significantly less than in the control group (p<0.05). Contractile responses of bladder strips to potassium chloride, electrical field stimulation, and carbachol were significantly lower after AI than in controls; responses in preparations from AI-mirabegron-treated animals were similar to those of controls. The AI group showed a significantly higher percentage of collagen (28.6 ± 1.57%) compared with the controls (8.65 ± 0.67%) and AI-mirabegron-treated animals (17.2 ± 2.32%). The mirabegron dose used in this study may potentially limit the translational value of the results. CONCLUSIONS: In the chronically ischemic rat bladder, treatment with mirabegron seems to protect bladder function and morphology, resulting in reduced bladder hyperactivity. If the results are valid for humans, they support ß3-AR agonism as a potential treatment of chronic ischemia-related bladder dysfunction.

Urinary incontinence after robot-assisted radical prostatectomy: pathophysiology and intraoperative techniques to improve surgical outcome.

Robot-assisted radical prostatectomy has been shown to have comparable and possibly improved postoperative continent rates compared with retropubic and laparoscopic radical prostatectomy. However, postoperative urinary incontinence has remained one of the most bothersome postoperative complications. The basic concept of the intraoperative technique to improve postoperative urinary continence is to maintain as normal anatomical and functional structure in the pelvis as possible. Therefore, improved knowledge of the normal structure in the pelvis should lead to a greater understanding of the pathophysiology of urinary incontinence, and further development of intraoperative techniques to improve the outcomes of urinary continence. It might be necessary to carry out three steps to realize improvement of the early return of urinary continence after robot-assisted radical prostatectomy: (i) preservation (bladder neck, neurovascular bundle, puboprostatic ligament, pubovesical complex, and/or urethral length, etc.); (ii) reconstruction (posterior and/or anterior reconstruction, and/or reattachment of the arcus tendineus to the bladder neck, etc.); and (iii) reinforcement (bladder neck plication and/or sling suspension, etc.). On the basis of these steps, further modifications during robot-assisted radical prostatectomy should be developed to improve urinary continence and quality of life after robot-assisted radical prostatectomy.

Impaired detrusor contractility in a rat model of chronic bladder ischemia.

OBJECTIVE: To examine the effect of chronic ischemia associated with vascular disorders on bladder function, we investigated bladder contractility and changes in morphology and nerve distribution in a rat model of chronic bladder ischemia. METHODS: Adult male Sprague-Dawley rats were divided into arterial endothelial injury, sham, and control groups. The injury group underwent balloon endothelial injury of the iliac arteries and received a 2% cholesterol diet. The sham group was only incised bilaterally in the inguinal region and received the 2% cholesterol diet. The control group did not undergo any procedure and received a regular diet (0.09% cholesterol). All animals were euthanized after 8 weeks. Bladders were removed and weighed, and sections were used for muscle strip contraction and histologic analyses. Cross-sections of dissected common iliac arteries were examined histologically. RESULTS: Bladder contractile response and tension were significantly decreased in the injury group compared with the sham and control groups. Tissue from the injury group exhibited marked arterial occlusion with wall thickening. In the injury group, the collagen and muscle ratio (0.80 ± 0.12) was significantly greater than in the control (P = .01) and sham (P = .04) groups. Significantly fewer protein gene product 9.5 (PGP9.5)-positive nerve fibers were found in the injury group (513 ± 53) than in the control (P = .01) and sham (P = .03) groups. CONCLUSION: Vascular occlusive disorders cause fibrosis and reduce the number of nerves innervating the bladder, which leads to decreased bladder contractility in a rat model of chronic bladder ischemia.