Blood flow of the urinary bladder: effects of outlet obstruction and correlation with bioenergetic metabolism

Effect of urinary retention on the surgical outcome of holmium laser enucleation of the benign prostatic hyperplasia

PURPOSE

To evaluate the effect of urinary retention (UR) on holmium laser enucleation of the prostate (HoLEP) in patients with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms.

MATERIALS AND METHODS

A retrospective analysis of a prospective cohort of patients who underwent HoLEP between January 2010 and December 2016 was performed. The perioperative factors, including the International Prostate Symptom Score, Overactive Bladder Symptom Score, prostate-specific antigen, urodynamic study results, uroflowmetry results, transrectal ultrasound prostate volume, operative time, morcellation time, enucleation weight, and complications, were evaluated. Postoperative evaluation was performed at 2, 3, and 6 months.

RESULTS

Overall, 903 patients were identified. The mean age and follow-up were 68.3 years and 6 months, respectively. Among the patients, 135 (15.0%) patients had a history of acute UR (AUR), and 36 patients (4.0%) had chronic UR (CUR). The mean detrusor pressures at maximum flow were 64.4, 74.3, and 77.7 cmH₂O (p<0.001). The mean maximum flow rates (Qmax) were 7.6, 6.6, and 4.8 mL/s (p<0.001). Additionally, the mean bladder outlet obstruction indices were 49.5, 61.1, and 69.4 (p<0.001). The postoperative Qmax improved in all three groups. The mean postvoid residual volumes (PVRs) were 55, 75, and 333 mL preoperatively; 20, 29, and 66 mL at 2 weeks; 16, 23, and 45 mL at 3 months; and 15, 22, and 52 mL at 6 months (p<0.001).

CONCLUSIONS

Voiding symptoms, PVR, and Qmax of BPH patients with preoperative AUR and CUR significantly improved after Ho-LEP, similar to those without preoperative UR.

Signal abnormalities of the bladder wall detected by native T1 mapping in patients with overactive bladder

OBJECT

Native T₁ mapping provides tissue-specific T₁ relaxation times, which can be used to identify structural changes in the various organs. The object of this article was to evaluate the bladder wall of patients with overactive bladder using native T₁ mapping and compare the relaxation times of patients and healthy controls.

MATERIAL AND METHODS

Seventeen patients with a diagnosis of overactive bladder and 15 healthy controls were enrolled in this prospective study. All participants underwent pelvic MRI and T₁ maps were acquired. Native T₁ relaxation times were calculated via regions of interest acquired from the anterosuperior wall of the bladder in all participants. Mean T₁ relaxation times of the overactive bladder patients were compared with those of controls.

RESULTS

Overactive bladder patients had statistically significantly higher T₁ relaxation times compared with controls (p = 0.004). In the subgroup analysis, there was no statistically significant difference between males (1113.42 ± 62.4) and females (1176.70 ± 100.9) regarding the T₁ relaxation times (p = 0.165). There were no correlations between age and T₁ relaxation times in patient or control groups (r = 0.057, p = 0.825, and r = 0.052, p = 0.932, respectively).

CONCLUSION

Native T₁ mapping can identify structural changes in the bladder wall of patients with overactive bladder. This technique has a promising role in the diagnosis of patients with suspected overactive bladder.

Multicenter evaluation of decompressive cystocentesis in the treatment of cats with urethral obstruction

OBJECTIVE

To investigate whether decompressive cystocentesis (DC) safely facilitates urethral catheterization (UC) in cats with urethral obstruction (UO).

ANIMALS

88 male cats with UO.

PROCEDURES

Cats were randomly assigned to receive DC prior to UC (ie, DC group cats; n = 44) or UC only (ie, UC group cats; 44). Abdominal effusion was monitored by serial ultrasonographic examination of the urinary bladder before DC and UC or before UC (DC and UC group cats, respectively), immediately after UC, and 4 hours after UC. Total abdominal effusion score at each time point ranged from 0 (no effusion) to 16 (extensive effusion). Ease of UC (score, 0 [easy passage] to 4 [unable to pass]), time to place urinary catheter, and adverse events were recorded.

RESULTS

No significant difference was found in median time to place the urinary catheter in UC group cats (132 seconds), compared with DC group cats (120 seconds). Median score for ease of UC was not significantly different between UC group cats (score, 1; range, 0 to 3) and DC group cats (score, 1; range, 0 to 4). Median change in total abdominal effusion score from before UC and DC to immediately after UC was 0 and nonsignificant in UC group cats (range, -5 to 12) and DC group cats (range, -4 to 8). Median change in effusion score from immediately after UC to 4 hours after UC was not significantly different between UC group cats (score, -1; range, -9 to 5) and DC group cats (score, -1; range, -7 to 5).

CONCLUSIONS AND CLINICAL RELEVANCE

DC did not improve time to place the urinary catheter or ease of UC in cats with UO.

Predictors of urgency improvement after Holmium laser enucleation of the prostate in men with benign prostatic hyperplasia

Purpose

To investigate the change in urinary urgency and predictors of urgency improvement after holmium laser enucleation of the prostate (HoLEP) in men with benign prostatic hyperplasia (BPH).

Materials and Methods

We retrospectively analyzed the medical records of patients who were treated with HoLEP for BPH and had preoperative urgency measuring ≥3 on a 5-point urinary sensation scale. Those with prostate cancer diagnosed prior to or after HoLEP, a history of other prostatic and/or urethral surgery, moderate to severe postoperative complications, and neurogenic causes were excluded. Patients who had improved urgency with antimuscarinic medication after HoLEP were excluded. We divided the patients into 2 groups based on urgency symptoms 3 months after HoLEP: improved and unimproved urgency. Improved urgency was defined as a reduction of 2 or more points on the 5-point urinary sensation scale. Preoperative clinical and urodynamic factors as well as perioperative factors were compared between groups.

Results

In total, 139 patients were included in this study. Voiding parameters in all patients improved significantly after HoLEP. Seventy-one patients (51.1%) had improved urgency, while 68 (48.9%) did not show any improvement. A history of acute urinary retention (AUR) and postvoid residual were associated with postoperative urgency improvement in univariate analysis. In multivariate analysis, a history of AUR was an independent factor affecting urgency improvement.

Conclusions

A preoperative history of AUR could influence the change in urgency after HoLEP surgery in patients with BPH.

Post-injury bladder management strategy influences lower urinary tract dysfunction in the mouse model of spinal cord injury

AIMS

To examine the effects of a different number of daily bladder squeezes on bladder dysfunction in mice with spinal cord injury (SCI).

METHODS

Spinal cord was transected at the Th8/9 in female C57BL/6N mice. Their bladders were manually squeezed to eliminate urine inside every day for 4 weeks. The mice were divided into three groups depending on the number of bladder squeezes; A: once daily, B: twice daily, C: three times daily. Four weeks after transection, single-filling cystometry were performed under an awake condition. NGF in the bladder mucosa and mRNA expression of P2X receptors and TRP channels in L6/S1 dorsal root ganglia (DRG) were measured.

RESULTS

Bladder weight in group C was less than that of group A. Bladder capacity, post-void residual, and the number of non-voiding contractions during the storage phase were significantly larger in group A compared to group B or C. The level of NGF in groups C were lower compared to group A or B. The expression of P2X3 and TRPA1 in groups B and C was decreased compared to group A. The expression of P2X2 was decreased in groups B compared to group A.

CONCLUSION

The post-injury bladder management after SCI with an increased number of daily bladder emptying improves the storage and voiding bladder dysfunction associated with the reduction of NGF in the bladder as well as P2X and TRP transcripts in lumbosacral DRG.

Cystometric parameters and the activity of signaling proteins in association with the compensation or decompensation of bladder function in an animal experimental model of partial bladder outlet obstruction

We conducted this study to determine whether the degree of detrusor contractility is associated with the compensation or decompensation of bladder function depending on the residual volume (RV) during the first two weeks after the onset of partial bladder outlet obstruction (BOO). Moreover, we also examined whether the degree of the phosphorylation and expression of signaling proteins [AMP-activated kinase (AMPK), extracellular signal‑regulated protein kinases 1 and 2 (ERK1/2) and protein kinase C (PKC)] is associated with the prevalence of compensation or decompensation of bladder function. Twenty-seven female Sprague-Dawley (SD) rats were randomly assigned to either the sham-operated group (n=7) or the group with partial bladder outlet obstruction (BOO) (n=20). We then measured cystometric parameters from three reproducible micturition cycles and averaged the results for a comparison between the two groups. Based on a cut-off value of a mean RV% of 25%, we subdivided our experimental animals into two subgroups: the subgroup with bladder compensation (mean RV%, <25%) and the subgroup with bladder decompensation (mean RV%, >25%). Our results indicated that the degree of detrusor overactivity (DO) was associated with the compensation or decompensation of bladder function depending on the RV during the first two weeks after the onset of BOO in an animal experimental model of partial BOO. Moreover, we also demonstrate that AMPK and ERK1/2 are involved in the compensation or decompensation of bladder function. Furthermore, our results suggest that PKC is not involved in two-phase bladder contraction. Alterations in the activities of signaling proteins, such as AMPK and ERK1/2 may prove to be helpful in the treatment of patients with voiding difficulty.

Protective effect of N-acetylcysteine against ischemia/reperfusion injury in rat urinary bladders

Ischemia/reperfusion (I/R) injury represents an important cause of bladder contractile dysfunction. One of the major causes leading to this dysfunction is thought to be reactive oxygen species formation. In this study, we investigated the potential benefit of N-acetylcysteine (NAC), a potent antioxidant that neutralizes free radicals, in a rat model of urinary bladder injury. NAC treatment rescues the reduction of contractile response to I/R injury in a dose-dependent manner. In addition, all levels of reactive oxygen species, lipid peroxidation, and NADPH-stimulated superoxide production in the I/R operation+NAC (I/R+NAC) group also decreased compared with a marked increase in the I/R operation+saline (I/R+S) group. Moreover, an in situ fluorohistological approach also showed that NAC reduces the generation of intracellular superoxides enlarged by I/R injury. Together, our findings suggest that NAC has a protective effect against the I/R-induced bladder contractile dysfunction via radical scavenging property.

Causative significance of bladder blood flow in lower urinary tract symptoms

The association between metabolic syndrome and lower urinary tract symptoms has been attracting enormous interest and attention. This enthusiasm is based on the presence of many common risk factors being involved in both metabolic syndrome and lower urinary tract symptoms, as shown by various epidemiological studies. Metabolic syndrome and lower urinary tract symptoms have many pathophysiological features in common, particularly overactive bladder. Herein, we analyze the pathophysiological relationship between metabolic syndrome and lower urinary tract symptoms with a special emphasis on bladder blood flow. We also propose a new treatment strategy for treating lower urinary tract symptoms from the viewpoint of bladder blood flow.

Molecular reactions and ultrastructural damage in the chronically ischemic bladder

PURPOSE

Clinical and basic research data suggest that pelvic ischemia may contribute to bladder overactivity. We characterized the molecular and ultrastructural reactions of the chronically ischemic bladder.

MATERIALS AND METHOD

A model of pelvic ischemia was developed by creating iliohypogastric/pudendal arterial atherosclerosis in rabbits. At 12 weeks conscious urinary frequency was examined, bladder blood flow was recorded and cystometrograms were done using general anesthesia. Bladder tissue was processed for molecular and ultrastructural analysis using quantitative real-time polymerase chain reaction, Western blot and transmission electron microscopy.

RESULTS

Conscious urinary frequency and the frequency of spontaneous bladder contractions significantly increased in animals with pelvic ischemia. Bladder ischemia up-regulated the gene and protein expression of hypoxia inducible factor-1α, transforming growth factor-β and nerve growth factor B. Vascular endothelial growth factor gene expression also increased but protein levels were unchanged. Transmission electron microscopy of ischemic bladder samples showed swollen mitochondria with degraded granules, thickened epithelium, deformed muscle fascicles, collagen deposition and impaired microvasculature with thickened intima and disrupted endothelial cell junctions. Degenerating axonal and Schwann cell profiles, and myelin sheath splitting around axons and Schwann cells were evident in ischemic bladders.

CONCLUSIONS

Interrupting pelvic blood flow resulted in an ischemic overactive bladder and significant increase in conscious urinary frequency. Molecular responses involving hypoxia inducible factor, transforming growth factor-β, vascular endothelial growth factor and nerve growth factor were associated with mitochondrial injury, fibrosis, microvasculature damage and neurodegeneration. Ischemia may have a key role in bladder overactivity and lower urinary tract symptoms.

Human bladder smooth muscle cell damage in disturbed oxygen tension

OBJECTIVE

To characterize human bladder smooth muscle cell reactions to disturbed oxygen tension. Clinical studies have shown a close correlation between bladder ischemia and lower urinary tract symptoms in elderly patients.

MATERIALS AND METHODS

Confluent cultured human bladder smooth muscle cells were incubated under normoxia, continuous hypoxia, and oxidative stress (hypoxia/reoxygenation) conditions using a computerized oxycycler system. After 48 hours, cell samples were collected and processed for fluorometric assessment of oxidative injury, enzyme immunoassay of antioxidant capacity, and transmission electron microscopy.

RESULTS

Lipid peroxidation was found in cell hypoxia and oxidative stress, whereas protein oxidation was evident in oxidative stress only. Cell antioxidant capacity decreased in oxidative stress but remained unchanged in hypoxia. Oxidative products were present in cell oxidative stress only, whereas nitrosative products increased in both hypoxia and oxidative stress conditions. Forty-eight hours of hypoxia and oxidative stress had no effect on cell senescence. Thickened deformed cell membrane, swollen mitochondria, and enlarged endoplasmic reticulum (ER) were found in cell hypoxia. Partially lost cell membrane with increased caveolae, swollen mitochondria with degraded cristae, splintered ER, and increased lysosomes were evident in cell oxidative stress.

CONCLUSION

Human bladder smooth muscle cells are highly reactive to nonconforming oxygen tension. Reactions to hypoxia are consistent with cell survival signaling to cope with lack of oxygen. Changes in oxidative stress indicate extensive damage and deterioration of the subcellular elements. Hypoxic and oxidative damage may be an important mechanism of smooth muscle degeneration in bladder conditions with disturbed oxygen tension.

Effect of tamsulosin on bladder microcirculation in a rat ischemia-reperfusion model, evaluated by pencil lens charge-coupled device microscopy system

OBJECTIVES

To investigate the effect of tamsulosin hydrochloride on bladder microcirculation in a rat ischemia-reperfusion model using a pencil lens charge-coupled device microscopy system (PLCMS).

METHODS

Changes in blood flow through a submucosal capillary of the rat bladder were measured during bladder filling using the PLCMS. One week after starting infusion of either physiological saline or tamsulosin, blood flow in the bladder was halted by bladder overdistention via an infusion of physiological saline. The bladder was then emptied to be reperfused with blood. Changes in blood flow through a submucosal capillary of the bladder during ischemia and reperfusion were measured using a PLCMS, and the data obtained for the control group and tamsulosin group were compared.

RESULTS

As the bladder was distended, the velocity of red blood cell flow in a submucosal capillary of the bladder slowed and stopped altogether when the bladder became overdistended. In the control group, capillary blood flow improved over time after release from overdistention but failed to return to the baseline level, demonstrating that reperfusion injury to bladder microcirculation was caused by bladder overdistention and emptying. In the tamsulosin group, capillary blood flow rapidly returned to baseline after release from overdistention.

CONCLUSIONS

Using a PLCMS, bladder microcirculation was able to be visualized and quantitatively assessed by measuring the velocity of blood flow in a submucosal capillary of the bladder. Findings from the present study suggest that tamsulosin hydrochloride exerts a protective effect on blood flow in ischemia-reperfusion injury of the bladder.

Effects of tamsulosin on bladder blood flow and bladder function in rats with bladder outlet obstruction

OBJECTIVES

To investigate the mechanism underlying the ameliorating effect of tamsulosin, an alpha(1)-adrenoceptor antagonist, on storage symptoms associated with benign prostatic hyperplasia, the effects of tamsulosin on bladder blood flow (BBF) and bladder function was evaluated in rats with bladder outlet obstruction (BOO).

METHODS

BOO was produced by partial ligature of the proximal urethra, which was maintained for 2 weeks. Tamsulosin was subcutaneously administered via an osmotic pump for 2 weeks immediately after the BOO surgery. The BBF in the sham-operated rats, the control BOO rats, and the tamsulosin-treated BOO rats was measured using the fluoromicrosphere method. Each rat was kept in a metabolic cage for observation of micturition behavior. Expression of the alpha(1)-adrenoceptor subtype mRNA in the vesical artery was measured by reverse transcriptase-polymerase chain reaction.

RESULTS

BBF was significantly reduced in BOO rats compared with sham-operated rats, and tamsulosin significantly increased the BBF in BOO rats. Tamsulosin ameliorated the decrease in mean voided volume in BOO rats with bladder masses < 500 mg. Expression of the alpha(1)-adrenoceptor subtype in the vesical artery was alpha(1a)- > alpha(1d)-adrenoceptors; almost no expression was observed of alpha(1b)-adrenoceptors in either sham-operated or BOO rats.

CONCLUSIONS

Tamsulosin increased BBF in BOO rats via an antagonistic effect, presumably on the alpha(1A)- and/or alpha(1D)-adrenoceptor in the vesical artery mainly, and improved the decrease in mean voided volume. Therefore, the results of this study suggest that tamsulosin improves bladder overactivity via improvement of BBF.

The effect of ischemia/reperfusion on rabbit bladder--role of Rho-kinase and smooth muscle regulatory proteins

OBJECTIVES

To detect the effect of ischemia/reperfusion (I/R) injury on rabbit bladder, using physiological study and immunoblotting techniques.

METHODS

Twelve male New Zealand White rabbits were separated into three groups of 4 rabbits each. Group 1 served as control. Group 2 rabbits (ischemia-alone group) underwent in vitro bilateral ischemia surgery for 2 hours. In group 3 (I/R group), bilateral ischemia was similarly induced, and the rabbits were allowed to recover for 2 weeks. The contractile responses to electrical field stimulation, adenosine triphosphate, carbachol, and KCl were recorded. Expression levels of the signaling targets, Rho-kinase (ROK), protein kinase C potentiated inhibitor (CPI-17), caldesmon (CaD), and calponin (CaP) were analyzed by Western blotting.

RESULTS

Ischemia alone resulted in significant reductions in the contractile responses, whereas I/R resulted in further decreases after all forms of stimulation. In muscle layer, ROK expression increased immediately after ischemia and recovered to the control level after 2 weeks' recovery. However, in mucosa layer, ROK expression showed no significant change after ischemia but significantly increased after reperfusion. After ischemic damage, CPI-17, the functional protein involved in smooth-muscle Ca(2+) sensitization, was significantly increased and then decreased after 2 weeks of reperfusion. The expression of CaP significantly increased after ischemia and decreased after reperfusion. Levels of high-molecular-weight CaD significantly decreased after ischemia and remained very low after reperfusion.

CONCLUSIONS

This study provides further understanding of the role of regulatory proteins in detrusor muscle after ischemia and I/R-induced contractile dysfunction.

Montelukast reduces ischaemia/reperfusion-induced bladder dysfunction and oxidant damage in the rat

The present study aimed to investigate the possible beneficial effects of the cysteinyl leukotriene-1 receptor antagonist montelukast on contractility and oxidant damage after ischaemia/reperfusion (I/R) of rat urinary bladder. The abdominal aorta of Sprague-Dawley rats was occluded to induce I/R. Montelukast (10 mg kg(-1)) or saline was administered intraperitoneally before I/R. In the sham-operated group, the abdominal aorta was left intact and the animals were treated with montelukast or saline. After decapitation, the bladder was removed and the tissue was either used for functional studies or stored for biochemical assays. In the I/R group, the isometric contractile responses of the bladder strips to carbachol (10(-8)-10(-4) M) were lower than those of the control group and were reversed by treatment with montelukast. Lipid peroxidation and myeloperoxidase activity of the bladder tissues in the I/R group were greater than in the sham-operated group. Montelukast treatment in the I/R group decreased these parameters compared with I/R alone. Similarly, the significant decrease in tissue glutathione level in the I/R group compared with controls was also prevented by montelukast. Treatment with montelukast almost completely reversed the low contractile responses of rat urinary bladder to carbachol and prevented oxidative tissue damage following I/R.

Aging impairs neurogenic contraction in guinea pig urinary bladder: role of oxidative stress and melatonin

The incidence of urinary bladder disturbances increases with age, and free radical accumulation has been proposed as a causal factor. Here we investigated the association between changes in bladder neuromuscular function and oxidative stress in aging and the possible benefits of melatonin treatment. Neuromuscular function was assessed by electrical field stimulation (EFS) of isolated guinea pig detrusor strips from adult and aged female guinea pigs. A group of adult and aged animals were treated with 2.5 mg·kg−1·day−1 melatonin for 28 days. Neurotransmitter blockers were used to dissect pharmacologically the EFS-elicited contractile response. EFS induced a neurogenic and frequency-dependent contraction that was impaired by aging. This impairment is in part related to a decrease in detrusor myogenic contractility. Age also decreased the sensitivity of the contraction to pharmacological blockade of purinergic and sensitive fibers but increased the effect of blockade of nitrergic and adrenergic nerves. The density of cholinergic and nitrergic nerves remained unaltered, but aging modified afferent fibers. These changes were associated with an increased level of markers for oxidative stress. Melatonin treatment normalized oxidative levels and counteracted the aging-associated changes in bladder neuromuscular function. In conclusion, these results show that aging modifies neurogenic contraction and the functional profile of the urinary bladder plexus and simultaneously increases the oxidative damage to the organ. Melatonin reduces oxidative stress and improves the age-induced changes in bladder neuromuscular function, which could be of importance in reducing the impact of age-related bladder disorders.

Gender-related neuronal and smooth muscle damage of guinea pig isolated urinary bladder from anoxia-glucopenia and reperfusion injury and its relationship to glycogen content

AIMS

To investigate the effects of anoxia and glucopenia (A-G) on both male and female guinea pig urinary bladder.

METHODS

In whole bladders superfused with oxygenated Krebs' solution, intrinsic nerves underwent electrical field stimulation (EFS) and smooth muscle stimulated with carbachol, ATP, and high potassium. The effect of 1, 2, or 3 hr A-G on the contractile response and the ensuing recovery in Krebs' solution, was monitored. Glycogen content in male and female urinary bladders was also measured.

RESULTS

Under different stimuli male urinary bladder proved to contract more efficiently than female organ. After 1 hr A-G the EFS response of male urinary bladder was virtually abolished and returned to 60% of control response in the recovery phase; in female bladder the EFS responses fully recovered during the reperfusion phase. Full recovery of the response to carbachol, ATP, and high potassium stimulations was observed in both genders. A-G had to be extended to 2 hr to cause smooth muscle impairment (higher in male than in female) and a neuronal impairment in female urinary bladders. When 2-deoxyglucose (2-DG), an inhibitor of glycolysis, was added during 1 hr A-G, both neuronal and smooth muscle damages were significantly enhanced in male, as well as, though to a lesser extent, in female bladder. A significantly higher glycogen content was observed in female as compared to male bladders, which was inversely related with the duration of exposure to A-G.

CONCLUSIONS

The higher resistance of female urinary bladder to A-G/reperfusion, can be partly ascribed to the higher glycogen content.

Persistent detrusor overactivity after transurethral resection of the prostate is associated with reduced perfusion of the urinary bladder

OBJECTIVES

To elucidate, in patients with benign prostatic hyperplasia (BPH), how often detrusor overactivity (DOA) is persistent after transurethral resection of the prostate (TURP) and if perfusion of the lower urinary tract influences postoperative outcomes.

PATIENTS AND METHODS

Fifty men with urodynamically confirmed DOA and bladder outlet obstruction due to BPH had a TURP. Before and 1 year after TURP the International Prostate Symptom Score (IPSS), quality of life (QoL) score, prostate-specific antigen (PSA) level and total prostatic volume (TPV) were evaluated. Also, the lower urinary tract was evaluated using pressure-flow studies and transrectal colour Doppler ultrasonography to assess the vascular resistive index (RI) as a variable of the perfusion of the lower urinary tract.

RESULTS

After TURP the IPSS, QoL score, PSA level and TPV decreased. Cystometric measurements showed that in 15 (30%) patients DOA was persistent after TURP. The mean (sd) maximum urinary flow rate increased from 9.20 (4.03) to 15.98 (4.62) mL/s and postvoiding residual urine volumes decreased from 109.38 (73.71) to 29.24 (45.00) mL. When men with persistent DOA (15 patients; group 1) were compared with those with no DOA after TURP (35; group 2) there was a statistically significantly higher RI of the bladder vessels in group 1, at 0.86 (0.068) than in group 2, at 0.68 ( 0.055) (P < 0.001).

CONCLUSIONS

Persistent DOA in men after TURP seems to be associated with increased vascular resistance of the bladder vessels with subsequent reduced perfusion and hypoxia.

New Unstable Bladder Model in Hypercholesterolemia Rats

OBJECTIVES

To evaluate the voiding function of the new vasculogenic erectile dysfunction (ED) model in hypercholesterolemic rats.

METHODS

We used 14 adult 12-week-old male Sprague-Dawley rats. The cholesterol group received a 1% cholesterol diet for 8 weeks. During the initial 2 weeks, they also drank water containing 3 mg/mL of NG-nitro-L-arginine methyl ester. After 8 weeks, we performed cystometrography, a detrusor strip contraction study, and pathologic examination of the detrusor to confirm voiding dysfunction. The results of the cholesterol and control groups were compared.

RESULTS

Compared with the control group values, the mean serum cholesterol and body weight were significantly elevated in the cholesterol group. The cholesterol group had shorter voiding intervals (377.6 +/- 205.4 versus 121.8 +/- 79.6 seconds, P <0.01) and a smaller functional bladder volume (1.4 +/- 0.7 versus 0.7 +/- 0.3 mL, P <0.05) on cystometrography compared with the control group. In the detrusor strip study, the cholesterol group had greater tension in spontaneous activities and an increase (13.1% +/- 5.6% versus 28.4% +/- 16.2%, P <0.05) in the proportion of purinergic components.

CONCLUSIONS

This vasculogenic ED rat model showed significantly frequent voiding on cystometrography. Considering the many epidemiologic and experimental data, in addition to the data from this model, ED and overactive bladder could share similar pathophysiologic features or be two symptoms of a systemic disorder. This rat model should be useful in evaluating the mechanism of ED and overactive bladder.

The detrusor muscle: an innocent victim of bladder outlet obstruction

OBJECTIVES

Benign prostatic hyperplasia (BPH) is considered a frequent cause of bladder outlet obstruction (BOO) and lower urinary tract symptoms (LUTS), although the physiopathologic mechanism through which BPH causes LUTS is not clear. Several morphologic and functional modifications of the bladder detrusor have been described in patients with BPH and could play a direct role in determining symptoms. The opinion is spreading that the enlarged prostates in patients with LUTS is nothing more than a mere bystander. Evidence has accumulated, however, supporting the role of BPH-related BOO as the direct cause determining bladder dysfunction and indirectly causing urinary symptoms. The present review addresses the bladder response to BOO, particularly focusing on the physiopathologic cascade that links obstructive BPH to bladder dysfunction.

METHODS

A literature review of peer-reviewed articles has been performed, including both in vivo and in vitro studies on human tissue and animal model experiments.

RESULTS

Epithelial and smooth muscle cells in the bladder wall are mechanosensitive, and in response to mechanical stretch stress caused by BOO, undergo modifications of gene expression and protein synthesis. This process involves several transduction mechanisms and finally alter the ultrastructure and physiology of cell membranes, cytoskeleton, contractile proteins, mitochondria, extracellular matrix, and neuronal networks.

CONCLUSIONS

BOO is the initiator of a physiopathologic cascade leading to deep changing of bladder structure and function. Before being a direct cause of storing-phase urinary symptoms, the bladder is the first innocent victim of prostatic obstruction.

Noninvasive Methods of Diagnosing Bladder Outlet Obstruction in Men. Part 1: Nonurodynamic Approach

PURPOSE

Many methods have been suggested for diagnosing bladder outlet obstruction, as defined by the gold standard of pressure flow studies. Difficulty arises when comparing completely different methods of diagnosing bladder outlet obstruction. A comprehensive review of the literature of the different methods used to diagnose bladder outlet obstruction by noninvasive means was performed with a view to allow such a comparison.

MATERIALS AND METHODS

A MEDLINE search was done of the published literature covering until the end of 2004 on noninvasive methods used to diagnose bladder outlet obstruction. A direct comparison of all different methods was made using the sensitivity and specificity, positive predictive value and likelihood ratio of each test. For many of the techniques these values were calculated from the data presented in the article.

RESULTS

A multitude of methods has been applied to diagnose bladder outlet obstruction. Broadly the methods were divided into nonurodynamic and noninvasive urodynamic methods. Nonurodynamic methods include symptoms, biochemical tests such as prostate specific antigen, ultrasound derived measurements such as post-void residual urine, bladder weight, prostate configuration and size, intravesical prostatic protrusion and the Doppler resistive index. Part 1 of the review explores and discusses the relative merits of the nonurodynamic based methods.

CONCLUSIONS

Ultrasound derived measures such as bladder wall thickness and bladder weight offer a promising possibility of diagnosing bladder outlet obstruction noninvasively. However, further reproducibility and large accuracy studies with better methodological standards are required before they can replace pressure flow studies.

The Beneficial Effect of Resveratrol on Rat Bladder Contractility and Oxidant Damage following Ischemia/Reperfusion

OBJECTIVE

The present study aimed to investigate the possible beneficial activities of resveratrol (3,5,4'-trans-trihydroxystilbene), a natural phytoalexin, on contractility and oxidant damage after ischemia/reperfusion (I/R) of the rat urinary bladder.

MATERIALS AND METHODS

The abdominal aorta of Sprague-Dawley rats was occluded for 60 min to induce ischemia and then allowed 60 min of reperfusion. Resveratrol (10 mg/kg) or saline was administered intraperitoneally 15 min before ischemia and immediately before reperfusion. In the sham-operated group, the abdominal aorta was left intact and the animals were treated with resveratrol or saline. The bladder samples were either used for functional studies or stored for biochemical assays.

RESULTS

In the I/R group, the isometric contractile responses of the bladder strips to carbachol (CCh; 10(-8)-10(-4) mol/l) were lower than those of the control group and were reversed by treatment with resveratrol. Histological evaluation revealed loss of urothelial cells, detachment and loss of urothelial cells and local ulcerated areas and severe inflammatory cell infiltration in the untreated I/R group, and regeneration of luminal mucosa and a significant decrease in the density of the inflammatory cell population in the resveratrol-treated I/R group. Lipid peroxidation and the myeloperoxidase activity of the bladder tissues in the I/R group were higher than in the sham-operated group. Resveratrol treatment in the I/R group decreased these parameters compared with I/R alone. Similarly, the significant decrease in tissue glutathione level in the I/R group compared with controls was also prevented by resveratrol.

CONCLUSION

Treatment with resveratrol almost completely reversed the low contractile responses of the rat urinary bladder to CCh and prevented oxidative tissue damage following I/R.

Edaravone protects against ischemia/reperfusion-induced functional and biochemical changes in rat urinary bladder

OBJECTIVES

To investigate the effects of edaravone on ischemia/reperfusion (I/R) injury in the rat bladder. Increasing evidence has shown that I/R are major etiologic factors in the progression of bladder dysfunction induced by partial outlet obstruction, and that part of the damage is due to the generation of free radicals. Edaravone is a newly developed radical scavenging agent that has been used for protection against I/R injury in patients with cerebral infarction.

METHODS

Thirty-five adult male rats were divided into five groups. Groups 1 to 4 underwent 1 hour of ischemia followed by 1 hour of reperfusion. Groups 1 to 3 were treated with edaravone at 1, 3, or 10 mg/kg body weight and group 4 with saline. Group 5 consisted of age-matched control rats. In vivo ischemia was created by clamping the vesical arteries for 1 hour. Reperfusion was accomplished by removing the clips and also lasted for 1 hour. Edaravone or saline was administered into the femoral artery after reperfusion for 30 minutes. After reperfusion, the bladder was excised and separated. The responses to electrical field stimulation, carbachol, and KCl were recorded. Other materials were analyzed for malondialdehyde as a measure of lipid peroxidation.

RESULTS

Edaravone administration resulted in protection of the contractile responses to both field stimulation and carbachol, although the responses to KCl were not affected. I/R resulted in an increase in malondialdehyde, which was reduced to control levels by edaravone.

CONCLUSIONS

These results suggest that edaravone has a potential protective effect against I/R-induced damage in the rat bladder.

Detrusor mitochondrial lipid peroxidation and superoxide dismutase activity in partial bladder outlet obstruction of rabbits

OBJECTIVES

Bladder outlet obstruction has shown to damage detrusor mitochondria with impaired detrusor contractility. One likely cause for mitochondrial injury is reactive oxygen species (ROS)-induced damages, including lipid peroxidation injury. We designed this study to examine this hypothesis.

MATERIALS AND METHODS

Placing a silicon ring around the bladder neck of male New Zealand rabbits induced bladder outlet obstruction. The bladders were removed 3 (N = 6), 7 (N = 6), and 14 days (N = 8) later. Sham operated animals (N = 6 for each time period) served as the controls. Contractile function of the bladder was assessed by the response of the detrusor strips to bethanechol and field stimulation. Detrusor mitochondrial superoxide dismutase (SOD) activity and mitochondrial content of malondialdehyde (MDA) were determined. Detrusor contents of phosphocreatine and adenine triphosphate (ATP) were assayed.

RESULTS

(1) Outlet obstruction induced an increase in the bladder weight and a decrease in the contractile function; (2) mitochondrial SOD activity significantly elevated in every time period of the obstruction, indicating a persistently increased ROS generation; (3) detrusor MDA level increased in 3-day obstruction animals. It returned to the control level in 7- and 14-day groups; (4) phosphocreatine content was significantly reduced in every time period of the obstruction; (5) ATP content was significantly decreased in 3- and 7-day groups; while 14-day obstruction group contained similar level as the sham-operated group.

CONCLUSIONS

This study shows that bladder outlet obstruction increases generation of ROS and enhances lipid peroxidation of detrusor mitochondria. The resulted mitochondrial damages might sustain, leading to persistently depressed energy production and impaired detrusor contractility.

Bladder Blood Flow and De-Obstructive Open Prostatectomy: Correlation with Clinical and Urodynamic Parameters

PURPOSE

To assess the relation between tissue blood flow changes during surgery with clinical and urodynamic parameters in obstructed patients.

MATERIAL AND METHODS

A prospective study was conducted in 18 symptomatic patients with bladder outlet obstruction undergoing retropubic prostatectomy. A symptom assessment and a preoperative urodynamic study were performed. To measure bladder blood flow a BLF-10 laser Doppler flowmeter and a blunt-tipped probe were used intraoperatively. Tissue flow was measured in TPU units (1 TPU unit=1 ml per minute per 100 mg of tissue). Six measurements were taken: two control in the rectus abdominis muscle and four in the detrusor, two before the incision of the prostatic capsule and two after closure. For the statistical analysis, Wilcoxon test and a regression analysis were performed.

RESULTS

Mean age was 70 years (range: 56-84). Six patients had an episode of acute urinary retention (AUR). No differences were found in the initial and final values of bladder blood flow of the rectus muscle and the bladder dome. A decrease of bladder blood flow in the anterior bladder wall was observed after prostate enucleation. AUR patients showed no differences in bladder blood flow values. Bladder blood flow (BBF) changes showed no correlation with any urodynamic or clinical parameter.

CONCLUSIONS

Laser Doppler flowmetry is useful to study BBF with low morbidity, ease of use and reproducibility. Following de-obstructive surgery, a decrease in BBF occurs, probably associated with surgery. These changes are similar in patients with and without AUR and show no correlation with other parameters studied.

Effect of anoxia-glucopenia and re-superfusion on intrinsic nerves of mammalian detrusor smooth muscle: Importance of glucose metabolism

AIMS

To investigate the effect of anoxia/glucopenia and re-superfusion on intrinsic nerves in the mammalian urinary bladder.

METHODS

Strips of detrusor smooth muscle were dissected from monkey and human urinary bladder and mounted for tension recording in organ baths superfused with Krebs solution. Human, monkey, and guinea-pig urinary bladders were treated to evaluate glycogen contents by a biochemical method.

RESULTS

Detrusor strips from both monkeys and humans had to be exposed to anoxia-glucopenia for up to 2-2.5 hr to observe a progressive decline in the response to electrical field stimulation (EFS) of the intrinsic nerves, at variance with guinea-pig detrusor strips. In contrast, the response to direct activation of the smooth muscle with carbachol remained almost unaltered. Incubation of human and monkey detrusor strips with 2-deoxyglucose (2-DG) during 1 hr anoxia-glucopenia, however, caused a marked damage to the intrinsic nerves. The glycogen contents of both human detrusor specimens and monkey urinary bladders were 2.0- and 1.4-fold higher, respectively, than that found in guinea-pig urinary bladder; furthermore, untreated monkey detrusor sections showed a greater number of glycogen granules as compared to those subjected to anoxia-glucopenia and re-superfusion. In guinea-pig and in monkey detrusor sections glycogen granules were found in smooth muscle cells but not in neurons of intramural ganglia.

CONCLUSIONS

A higher susceptibility of guinea-pig as compared to monkey and human nerves has been demonstrated; it is suggested that anaerobic glucose metabolism during anoxia-glucopenia is crucial for the functional recovery of detrusor intrinsic nerves from damage caused by anoxia-glucopenia and re-superfusion.

In vitro neuroprotection by novel antioxidants in guinea-pig urinary bladder subjected to anoxia-glucopenia/reperfusion damage

In a previous study, the neuroprotection provided by some hindered phenols of synthetic nature and alpha-tocopherol in guinea-pig detrusor strips subjected to ischaemia/reperfusion-like conditions was shown to be related directly to the antioxidant activity. The aim of the present study was to estimate the capability of three novel chimeric molecules derived by assembling known antioxidant moieties, namely FeAOX-6, comprising a chromanyl head and the polyisoprenyl sequence characteristic for lycopene, FeCD-52, derived from the conjugation of ascorbic acid and a polyphenol moiety (FeRS-4) and FeDG-17, derived from the combination of ascorbic acid and a chromanyl head, to confer neuroprotection in an in vitro model of guinea-pig whole urinary bladder subjected to anoxia-glucopenia/reperfusion injury. The antioxidant potential of these compounds was determined by oxygen radical absorbance capacity (ORAC) and phochemiluminescence (PCL) assays to test their peroxyl and anion superoxide (O2(*-)) radical trapping activity, respectively. FeAOX-6, FeCD-52 and FeDG-17 exerted both strong neuroprotective and antioxidant activity, significantly higher than those exerted by the individual component moieties. The antioxidant activity of FeCD-52 was 37-fold higher than that of the reference compound trolox. FeAOX-6 exerted remarkable neuroprotective activity, superior to that of FeCD-52 or FeDG-17, in spite of its lower antioxidant activity. These findings indicate that assembling antioxidant moieties yields neuroprotective agents, the effectiveness of which, however, is not related to the antioxidant activity. It is possible that a different partitioning in cell compartments critically involved in the oxidative damage pathway plays a role in neuroprotection exerted by these compounds.

THE EFFECT OF CHRONIC BLADDER OUTLET OBSTRUCTION ON NEURONAL NITRIC OXIDE SYNTHASE EXPRESSION IN THE INTRAMURAL GANGLIA OF THE GUINEA PIG BLADDER

PURPOSE

We examined the effect of chronic partial outlet obstruction on expression of neuronal nitric oxide synthase (nNOS) in the intramural ganglion cells of the guinea pig bladder.

MATERIALS AND METHODS

Partial urethral ligation was done in young male guinea pigs. The animals were sacrificed 2, 4, 6, 8 and 12 weeks after partial outlet obstruction and nNOS immunohistochemistry was done in the intramural neurons of the bladder. This was compared to controls (normal and sham operated). In addition, the mRNA expression of nNOS in bladders of 4-week sham operated and operated animals was also investigated using real-time quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Two weeks after urethral obstruction a decrease in the number of nNOS positive intramural neurons was detected. This decrease was most drastic at 4 weeks. Cell counting showed a 60.6% decrease in the number of nNOS positive neurons compared to controls. Some neurons appeared to undergo degenerative changes, such as irregular outline, vacuolation and lysis. At 6 weeks the number of nNOS positive neurons increased from the nadir level at 4 weeks and the increase was sustained until 12 weeks, when the number of nNOS positive neurons was almost at the level of controls. Quantitative reverse transcriptase-polymerase chain reaction also showed 42.4% down-regulation of nNOS expression 4 weeks after obstruction comparing with sham operation.

CONCLUSIONS

Partial urethral ligation resulted in an initial decrease in nNOS positive neurons, which have been due to actual neuronal loss and/or enzyme down-regulation. This may be attributable to regional hypoxia as a result of decreased blood flow consequent to high intravesical pressure created by partial ligation. The decrease in nNOS expression followed by a compensatory increase in nNOS positive neurons also suggests an attempt or mechanism to up-regulate nitric oxide bioactivity following increased bladder outlet resistance.

Melatonin treatment protects against sepsis-induced functional and biochemical changes in rat ileum and urinary bladder

Sepsis is commonly associated with enhanced generation of reactive oxygen metabolites, which lead to multiple organ dysfunction. The aim of this study was to examine the role of melatonin, a potent antioxidant, in protecting the intestinal and bladder tissues against damage in a rat model of sepsis. Sepsis was induced by cecal ligation and perforation (CLP) in Wistar Albino rats. Sham operated (control) and CLP group received saline or melatonin (10 mg/kg, ip) 30 minutes prior to and 6 hours after the operation. Sixteen hours after the surgery, rats were decapitated and the intestinal and urinary bladder tissues were used for contractility studies, or stored for the measurement of malondialdehyde (MDA) content -an index of lipid peroxidation-, glutathione (GSH) levels -a key antioxidant- and myeloperoxidase (MPO) activity- an index of neutrophil infiltration-. Ileal and bladder MDA levels in the CLP group were significantly increased (p < 0.001) with concomitant decreases in GSH levels (p < 0.01 - p < 0.001) when compared to the control group. Similarly, MPO activity was significantly increased (p < 0.001) in both ileum and bladder tissues. On the other hand, melatonin treatment significantly reversed (p < 0.001) the elevations in MDA and MPO levels, while reduced GSH levels were increased back to the control levels (p < 0.01 - p < 0.001). In the CLP group, the contractility of the ileal and bladder tissues decreased significantly compared with controls. Melatonin treatment of the CLP group restored these responses. In this study, CLP induced dysfunction of the ileal and bladder tissue of rats was reversed by melatonin treatment. Moreover, melatonin, as an antioxidant, abolished the elevation in lipid peroxidation products and myeloperoxidase activity, and reduction in the endogenous antioxidant glutathione and thus protected the tissues against sepsis-induced oxidative damage.

Oral Kohki Tea and its protective effect against in vitro ischemic damage to the bladder

AIMS

Results of several studies indicate that ischemia/reperfusion (I/R) is an etiological factor in the contractile dysfunctions induced by partial bladder outlet obstruction in animal models. In support of this hypothesis, pretreatment of rabbits with Kohki Tea (Engelhardtia chrysolepis), a Japanese herbal drink very high in antioxidant activity, significantly reduced the contractile dysfunctions induced by partial outlet obstruction. The current study was designed to determine if pretreating rabbits with Kohki Tea could protect the bladder against the contractile damage induced by in vitro ischemia followed by re-oxygenation.

METHODS

Forty-eight New Zealand White rabbits were separated into two groups of 24; Group 1 was pretreated by oral gavage for 3 weeks with Kohki Tea and Group 2 received vehicle (water). Each rabbit was anesthetized with pentobarbital. The urinary bladder was rapidly removed and eight longitudinal muscle strips were cut from the bladder body. Each strip was mounted in a separate 15-ml bath containing Tyrode's solution with glucose (1 mg/ml) and maintained at 37 degrees C. All strips were equilibrated for 30 min with a gas mixture of 95% O2 and 5% CO2. At the end of this period of time, all strips were stimulated with field stimulation (FS) carbachol and KCl. After the last wash, the aeration was changed to hypoxic mixture (nitrogen-CO2) without glucose. At the end of 2 hr, the aeration was changed back to the normal 95% O2 and 5% CO2, and glucose was added to the buffer. After 1 hr of re-oxygenation, a second set of stimulations was performed. In order to represent hyperreflexia, the strips were stimulated at 32-Hz FS at 5-min intervals during the hypoxic period in half of the in vitro experiments.

RESULTS

The results showed that Kohki Tea pretreatment protected the bladder's response to FS from the detrimental effects of repetitive stimulation and the detrimental effects of both in vitro ischemia and repetitive stimulation on the contractile responses to carbachol and KCl.

CONCLUSIONS

These data are consistent with the concept that Kohki Tea acts by protecting the bladder from cellular damage caused by hypoxia and the generation of free radicals.