Comparison of the effects of two anesthetics, isoflurane and urethane, on bladder function in rats.

We compared the effects of two anesthetics, isoflurane and urethane on bladder function in rats. Arterial pressure, cystometry (CMG), and rhythmic bladder contractions (RBCs) under isovolumetric conditions, mechanosensitive single-unit afferent activities (SAAs), bladder compliance and bladder myogenic microcontractions (bladder microcontractions), and bladder blood flow, and blood and urine biochemical tests were investigated in isoflurane- or urethane-anesthetized female rats. In results of the CMG, 3/8 rats in the isoflurane group and 7/7 rats in the urethane group showed constant bladder neurogenic contractions for micturition, whereas 5/8 rats in the isoflurane group showed unstable contractions or overflow incontinence. The RBCs appeared in the urethane group but not in the isoflurane group, and SAAs in both the Aδ- and C-fibers, bladder compliance, and bladder microcontractions in the isoflurane group were higher than those in the urethane group during bladder distension. The blood biochemical test showed that the serum calcium level was higher in the isoflurane group. The mean arterial pressure and bladder blood flow were not different between the groups. The results showed that urethane anesthesia more retains bladder neurogenic contractions for micturition compared to isoflurane. In contrast, isoflurane anesthesia more retains bladder function during the storage phase compared to urethane.

Feasibility, Safety, and Long-Term Outcomes of Zero-Contrast Percutaneous Coronary Intervention in Patients With Chronic Kidney Disease.

BACKGROUND: The long-term safety and utility of intravascular ultrasound (IVUS)-guided zero-contrast percutaneous coronary intervention (PCI) in patients with chronic kidney disease (CKD) are unknown.Methods and Results: A total of 698 consecutive patients treated with PCI (1,061 procedures) in our center were studied. Patients with acute coronary syndrome, who are on maintenance hemodialysis, and who had a planned rotational atherectomy were excluded. Finally, they were divided into 2 groups: zero-contrast PCI (n=55, 78 procedures) and conventional PCI (n=462, 670 procedures). After propensity score matching, 50 patients were matched for each group to evaluate long-term outcomes. Primary endpoints were major adverse cardiovascular events (MACE), including all-cause death, non-fatal myocardial infarction (MI), and clinically driven target lesion revascularization. All patients in the zero-contrast PCI group had stage 3-5 CKD with an estimated glomerular filtration rate of 38.3±14.8 mL/min/1.73 m2. Zero-contrast PCI was successful in all 78 procedures without renal events such as acute kidney injury or emergent hemodialysis and procedural complications such as coronary perforation or periprocedural MI. During a follow-up period of 32 months, 7 patients died (1 cardiac, 6 non-cardiovascular), and 4 patients were introduced to renal replacement therapy. The incidence of MACE was similar between the zero-contrast and conventional PCI groups (log-rank, P=0.95). CONCLUSIONS: IVUS-guided zero-contrast PCI might be safe and feasible in patients with CKD with satisfactory acute and long-term renal and cardiovascular outcomes.

Sex differences in the prevalence and prognostic impact of physical frailty and sarcopenia among older patients with heart failure.

BACKGROUND AND AIMS: Frailty and sarcopenia are common and confer poor prognosis in elderly patients with heart failure; however, gender differences in its prevalence or prognostic impact remain unclear. METHODS AND RESULTS: We included 1332 patients aged ≥65 years, who were hospitalized for heart failure. Frailty and sarcopenia were defined using the Fried phenotype model and Asian Working Group for Sarcopenia criteria, respectively. Gender differences in frailty and sarcopenia, and interactions between sex and prognostic impact of frailty/sarcopenia on 1-year mortality were evaluated. Overall, 53.9% men and 61.0% women and 23.7% men and 14.0% women had frailty and sarcopenia, respectively. Although sarcopenia was more prevalent in men, no gender differences existed in frailty after adjusting for age. On Kaplan-Meier analysis, frailty and sarcopenia were significantly associated with 1-year mortality in both sexes. On Cox proportional hazard analysis, frailty was associated with 1-year mortality only in men, after adjusting for confounding factors (hazard ratio [HR], 1.94; 95% confidence interval [CI], 1.19-3.16; P = 0.008 for men; HR, 1.63; 95% CI, 0.84-3.13; P = 0.147 for women); sarcopenia was an independent prognostic factor in both sexes (HR, 1.93; 95% CI, 1.13-3.31; P = 0.017 for men; HR, 3.18; 95% CI, 1.59-5.64; P = 0.001 for women). There were no interactions between sex and prognostic impact of frailty/sarcopenia (P = 0.806 for frailty; P = 0.254 for sarcopenia). CONCLUSIONS: Frailty and sarcopenia negatively affect older patients with heart failure from both sexes. CLINICAL TRIALS: This study was registered at the University Hospital Information Network (UMIN-CTR, unique identifier: UMIN000023929) before the first patient was enrolled.

Sarcopenic obesity is associated with impaired physical function and mortality in older patients with heart failure: insight from FRAGILE-HF.

BACKGROUND: The purpose of this study was to clarify the prevalence, association with frailty and exercise capacity, and prognostic implication of sarcopenic obesity in patients with heart failure. METHODS: The present study included 779 older adults hospitalized with heart failure (median age: 81 years; 57.4% men). Sarcopenia was diagnosed based on the guidelines by the Asian Working Group for Sarcopenia. Obesity was defined as the percentage of body fat mass (FM) obtained by bioelectrical impedance analysis. The FM cut-off points for obesity were 38% for women and 27% for men. The primary endpoint was 1-year all-cause death. We assessed the associations of sarcopenic obesity occurrence with the short physical performance battery (SPPB) score and 6-minute walk distance (6MWD). RESULTS: The rates of sarcopenia and obesity were 19.3 and 26.2%, respectively. The patients were classified into the following groups: non-sarcopenia/non-obesity (58.5%), non-sarcopenia/obesity (22.2%), sarcopenia/non-obesity (15.3%), and sarcopenia/obesity (4.0%). The sarcopenia/obesity group had a lower SPPB score and shorter 6MWD, which was independent of age and sex (coefficient, - 0.120; t-value, - 3.74; P < 0.001 and coefficient, - 77.42; t-value, - 3.61; P < 0.001; respectively). Ninety-six patients died during the 1-year follow-up period. In a Cox proportional hazard analysis, sarcopenia and obesity together were an independent prognostic factor even after adjusting for a coexisting prognostic factor (non-sarcopenia/non-obesity vs. sarcopenia/obesity: hazard ratio, 2.48; 95% confidence interval, 1.22-5.04; P = 0.012). CONCLUSION: Sarcopenic obesity is a risk factor for all-cause death and low physical function in older adults with heart failure. TRIAL REGISTRATION: University Hospital Information Network (UMIN-CTR: UMIN000023929 ).

Living Anionic Addition Reaction of 1,1-Diphenylethylene Derivatives: One-Pot Synthesis of ABC-type Chain-End Sequence-Controlled Polymers.

In this study, a 1:1 addition reaction using 1,1-diphenylethylene (DPE) derivatives, referred to as the "living anionic addition reaction", was established to regulate the sequence of vinyl compounds having negligible homopolymerizability. The stoichiometric and successive addition reaction between a DPE anion and more reactive DPE derivatives proceeded quantitatively when the electrophilicity of the DPE derivatives was sufficiently enhanced by electron-withdrawing groups such as (trimethylsilyl)ethynyl and acyl groups. The relative electrophilicity of the DPE derivatives was predicted by Hammett's law and the ß-carbon chemical shifts of the carbon-carbon double bonds. AB- and ABC-type chain-end sequence-controlled polystyrenes with well-defined structures were synthesized by reacting two or three DPE derivatives with difunctional anionic living polystyrene in increasing order of their electrophilicity in a one-pot reaction.

Lacking transient receptor potential melastatin 2 attenuates lipopolysaccharide-induced bladder inflammation and its associated hypersensitivity in mice.

OBJECTIVE: To study the role of transient receptor potential melastatin 2 in bladder function and inflammation-associated hypersensitivity. METHODS: We evaluated physiological function of the bladder and intravesical lipopolysaccharide-induced inflammatory nociceptive responses in female wild-type and transient receptor potential melastatin 2-knockout mice. In vivo frequency/volume and decerebrated unanesthetized cystometry measurements, as well as in vitro detrusor strip functional studies, were carried out to evaluate bladder function. Mice received intravesical lipopolysaccharide (2.0 mg/mL) or saline instillation to evaluate responses to bladder inflammation. Voiding and bladder pain-like behaviors, cystometry measurements and histological evaluation were carried out before and after intravesical lipopolysaccharide instillation. RESULTS: Few phenotypic differences in in vivo and in vitro physiological function were found between the two genotypes. Comparison of measurements taken before and 24-48 h after intravesical lipopolysaccharide instillation showed that voiding parameters did not change in transient receptor potential melastatin 2-knockout mice, whereas an increased voiding frequency was observed in wild-type mice. At 24 h after intravesical lipopolysaccharide instillation, the numbers of bladder pain-like behaviors and of infiltrated inflammatory cells in the bladder submucosal layer were significantly increased, and the voided volume and the intercontraction interval were significantly decreased on cystometry measurements in wild-type mice compared with those in both transient receptor potential melastatin 2-knockout mice and in wild-type mice treated with saline instillation. CONCLUSIONS: Although the physiological roles of transient receptor potential melastatin 2 channels in the bladder might be limited, inflammation and associated hypersensitivity of the bladder caused by intravesical lipopolysaccharide instillation are attenuated in transient receptor potential melastatin 2-knockout mice, suggesting pathophysiological roles of transient receptor potential melastatin 2 channels in these processes.

KPR-5714, a Novel Transient Receptor Potential Melastatin 8 Antagonist, Improves Overactive Bladder via Inhibition of Bladder Afferent Hyperactivity in Rats.

Transient receptor potential (TRP) melastatin 8 (TRPM8) is a temperature-sensing ion channel mainly expressed in primary sensory neurons (Aδ-fibers and C-fibers in the dorsal root ganglion). In this report, we characterized KPR-5714 (N-[(R)-3,3-difluoro-4-hydroxy-1-(2H-1,2,3-triazol-2-yl)butan-2-yl]-3-fluoro-2-[5-(4-fluorophenyl)-1H-pyrazol-3-yl]benzamide), a novel and selective TRPM8 antagonist, to assess its therapeutic potential against frequent urination in rat models with overactive bladder (OAB). In calcium influx assays with HEK293T cells transiently expressing various TRP channels, KPR-5714 showed a potent TRPM8 antagonistic effect and high selectivity against other TRP channels. Intravenously administered KPR-5714 inhibited the hyperactivity of mechanosensitive C-fibers of bladder afferents and dose-dependently increased the intercontraction interval shortened by intravesical instillation of acetic acid in anesthetized rats. Furthermore, we examined the effects of KPR-5714 on voiding behavior in conscious rats with cerebral infarction and in those exposed to cold in metabolic cage experiments. Cerebral infarction and cold exposure induced a significant decrease in the mean voided volume and increase in voiding frequency in rats. Orally administered KPR-5714 dose-dependently increased the mean voided volume and decreased voiding frequency without affecting total voided volume in these models. This study demonstrates that KPR-5714 improves OAB in three different models by inhibiting exaggerated activity of mechanosensitive bladder C-fibers and suggests that KPR-5714 may provide a new and useful approach to the treatment of OAB. SIGNIFICANCE STATEMENT: TRPM8 is involved in bladder sensory transduction and plays a role in the abnormal activation in hypersensitive bladder disorders. KPR-5714, as a novel and selective TRPM8 antagonist, may provide a useful treatment for the disorders related to the hyperactivity of bladder afferent nerves, particularly in overactive bladder.

Bladder sensation evaluation of a carrageenan-induced chronic prostatitis model using a direct measurement of the bladder mechanosensitive single-unit afferent nerve activity.

AIMS: Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) causes long-standing pain and/or storage symptoms. This study aimed to evaluate the likelihood of deterioration of bladder sensation in a carrageenan-induced CP/CPPS model by direct measurement of the bladder mechanosensitive single-unit afferent nerve activity. METHODS: In this study, male adult Sprague-Dawley rats were used. They were injected 50 µL of 3% λ-carrageenan or its vehicle (saline) into both lobes of the ventral prostate. Seven days following injection, the pain behavior at the pelvic-perineal area (using von Frey filaments), prostatic blood flow (using a laser blood flowmeter), and histology were examined along with cystometry (under conscious free-moving condition) and mechanosensitive single-unit afferent nerve activity (under urethane anesthesia). RESULTS: The prostate showed increased tissue weight and decreased blood flow and inflammatory cell infiltration in the carrageenan group compared to the control group. Consequently, the threshold of the pain behavior was decreased, and the basal and threshold pressures of the bladder were increased in the carrageenan group. In contrast, no significant differences of bladder histology and other cystometric parameters were found between the groups. Regarding Aδ- or C-fibers, the mechanosensitive afferent nerve activities revealed no differences in either group. CONCLUSIONS: The carrageenan-induced CP/CPPS rat model showed edema, ischemia, and inflammatory pain in the prostate, whereas a little change was detected in bladder sensation. These findings, which were evaluated using a direct measurement of the mechanosensitive single-unit afferent nerve activity, suggest that the bladder sensation is unlikely deteriorated in this model.

May perioperative ultrasound-guided pelvic floor muscle training promote early recovery of urinary continence after robot-assisted radical prostatectomy?

AIMS: The efficacy of perioperative pelvic floor muscle training (PFMT) for continence recovery after robot-assisted radical prostatectomy (RARP) remains unclear. Visualization of the bladder neck and urethra using transperineal ultrasound (US) may promote self-recognition of urethral closure during PFM contraction. This study aimed to examine whether transperineal US-guided PFMT promotes early recovery of post-RARP incontinence. METHODS: This prospective cohort study included 116 men undergoing RARP. All men were offered to undergo transperineal US-guided PFMT, and 36 men agreed. The protocol consisted of biofeedback PFMT using transperineal US before RARP and 1-month after RARP with verbal instruction of PFMT immediately after urethral catheter removal. The remaining 80 patients received verbal instruction for PFMT alone. Continence recovery was defined as the number of days requiring a small pad (20 g) per day by self-report. RESULTS: No differences were observed in demographic or peri-operative parameters between the two groups except the longer operative time in the US-guided PFMT group. The mean time until continence recovery was significantly shorter in the US-guided PFMT group (75.6 ± 100.0 days) than in the verbal-PFMT group (121.8 ± 132.0 days, P = 0.037). Continence recovery rates within 30 days were 52.8% (19/36) and 35.4% (28/80) in the US-guided PFMT and verbal-PFMT groups, respectively (P = 0.081). US-guided PFMT was associated with better postoperative continence status (adjusted hazard ratio [95% confidence interval]: 0.550 [0.336-0.900], P = 0.017). CONCLUSIONS: The results showed that transperineal US-guided PFMT perioperatively was associated with early recovery of urinary continence after RARP.

Longitudinal change of comprehensive lower urinary tract symptoms and various types of urinary incontinence during robot-assisted radical prostatectomy.

AIMS: To clarify longitudinal change of lower urinary tract symptoms (LUTS) and various types of urinary incontinence following robot-assisted radical prostatectomy (RARP) using validated questionnaires. MATERIALS AND METHODS: The core lower urinary tract symptom score (CLSS) and the International Consultation on Incontinence Questionnaire (ICIQ)-Short Form (SF) questionnaires were administered to 607 consecutive, treatment-naïve men receiving RARP before and after surgery. The time course of comprehensive LUTS and various types of urinary incontinence, including stress-, urgency-, and urinary incontinence with no obvious reason, were evaluated. Continence recovery rates were compared for the different types of incontinence using Cox hazard regression analysis. RESULTS: After surgery, stress urinary incontinence (SUI) was reported most frequently (32% of cases) as the chief complaint with the most impact on daily life, as assessed by the CLSS questionnaire, followed by urgency urinary incontinence (UUI; 27% of cases). The rates of continence recovery differed among the different types of urinary incontinence, such as after urinating, when dressed, when asleep, when physically active or exercising, when coughing or sneezing, before reaching the toilet, and for no obvious reason. Incontinence for no obvious reason at 1 month after RARP was a strongest prognostic factor of delayed continence recovery (hazard ratio, 0.61; P < 0.0001), whereas patients reporting SUI and UUI gradually regained continence. CONCLUSIONS: Further time course on continent recovery after RARP would be more precisely predictable based on the incontinence status at one month postoperatively. Especially, incontinence with no obvious reason would be a significant factor for delayed recovery.

Inhibitory effects of silodosin on the bladder mechanosensitive afferent activities and their relation with bladder myogenic contractions in male rats with bladder outlet obstruction.

AIMS: We investigated the effects of silodosin, an α1A-adrenoceptor (AR) antagonist, on bladder function, especially on non-voiding contractions (NVCs), in a male rat model of bladder outlet obstruction (BOO) by evaluating cystometry (CMG) findings and bladder mechanosensitive single-unit afferent activities (SAAs), related with microcontractions, which may be similar with NVCs and to be of myogenic origin, in the rat model. METHODS: BOO was created by partial ligation of the posterior urethra. At 4 days after surgery for BOO, an osmotic pump filled with silodosin (0.12 mg/kg/day) or its vehicle was subcutaneously implanted. At 10 days after surgery, CMG and SAAs measurements were taken under conscious and urethane-anesthetized conditions, respectively. The SAAs of Aδ- and C-fibers, which were identified by electrical stimulation of the pelvic nerve and by bladder distention, and intravesical pressure were recorded during constant bladder-filling with saline. Microcontractions were divided into three phases: "ascending," "descending," and "stationary." RESULTS: The silodosin-treated group showed a smaller number of NVCs in CMG measurements and lower SAAs of both Aδ- and C-fibers than the vehicle-treated group during bladder-filling. Moreover, in the vehicle-treated groups, the SAAs of both fibers for the ascending phase of microcontractions were significantly higher than those for the other two phases. On the contrary, no significant change was found between any of these three phases in the silodosin-treated group. CONCLUSION: The present results suggest that silodosin inhibits the SAAs of mechanosensitive Aδ- and C-fibers at least partly due to suppressing myogenic bladder contractions in male BOO rats.

KPR-2579, a novel TRPM8 antagonist, inhibits acetic acid-induced bladder afferent hyperactivity in rats.

AIMS: Transient receptor potential melastatin 8 (TRPM8) is proposed to be a promising therapeutic target for hypersensitive bladder disorders. We examined the effects of KPR-2579, a novel selective TRPM8 antagonist, on body temperature and on mechanosensitive bladder single-unit afferent activities (SAAs) provoked by intravesical acetic acid (AA) instillation in rats. METHODS: Female Sprague-Dawley rats were used. Effects of cumulative intravenous (i.v.) administrations of KPR-2579 (0.03-1 mg/kg) on deep body temperature were investigated (N = 18). In separate animals, effects of bolus administration of KPR-2579 (0.03 or 0.3 mg/kg, i.v.) on bladder hyperactivity induced by intravesical instillation of 0.1% AA were investigated using cystometry (N = 57) in a conscious free-moving condition or urethane-anesthetized condition, and SAA measurements (N = 41) were performed in a urethane-anesthetized condition. RESULTS: KPR-2579 at any doses tested did not affect body temperature. In cystometry measurements, a high dose (0.3 mg/kg) of KPR-2579 counteracted the shortened intercontraction interval provoked by AA instillation. In SAA measurements, 48 single afferent fibers (n = 24 in each fiber) were isolated. AA instillations significantly increased the SAAs of C fibers, but not of Aδ fibers, in the presence of KPR-2579's vehicle and a low dose (0.03 mg/kg) of KPR-2579. Pretreatment with a high dose (0.3 mg/kg) of KPR-2579 significantly inhibited the AA-induced activation of C-fiber SAAs. CONCLUSION: The present results suggest that TRPM8 channels play a role in the AA-induced pathological activation of mechanosensitive bladder C fibers in rats. KRP-2579 may be a promising drug for hypersensitive bladder disorders.

Diagnostic value of urinary CXCL10 as a biomarker for predicting Hunner type interstitial cystitis.

AIM: To investigate the feasibility of chemokines and cytokines potentially elevated in the bladder tissue of Hunner type interstitial cystitis (HIC) as urinary markers for distinguishing HIC from non-Hunner type interstitial cystitis (NHIC) METHODS: Urine specimens were collected from 41 HIC patients, 25 NHIC patients, and 31 healthy volunteers (control). The supernatants of urine specimens were subjected to ELISA kits for measurements of 10 cytokines and chemokines, whose gene expression was known to be elevated in HIC bladder tissue. Urinary levels normalized by urinary creatinine (Cr) concentration were compared among three groups. Efficiency in differentiating IC and IC subtypes was explored by ROC analysis. The correlation of marker levels with symptom severity, assessed by O'Leary-Sant's symptom index (OSSI) and problem index (OSPI), was examined. RESULTS: The urinary levels of CXCL10 and NGF were significantly higher in HIC than NHIC. CXCL10 and NGF differentiated HIC against NHIC with AUC of 0.78 and 0.68, respectively. Combination of CXCL10 and NGF levels yielded an AUS of 0.81. The CXCL10 cut-off of 53.2 pg/mg Cr had sensitivity of 46.1%, specificity of 93.7%, positive predictive value of 97.7%, and negative predictive value of 60.0%. The urinary level of other cytokines showed no significant difference between HIC and NHIC. Significant correlation with symptoms was detected for CXCL10 alone. CONCLUSION: The results suggested that increased urinary level of CXCL10 combined with or without high NGF level could be a promising supplementary biomarker for differentiating HIC from NHIC with modest sensitivity and high specificity.

Advertising and Risk Selection in Health Insurance Markets.

This paper studies the impact of advertising as a channel for risk selection in Medicare Advantage. We provide evidence that insurer advertising is responsive to the gains from risk selection. Then we develop and estimate an equilibrium model of Medicare Advantage with advertising, allowing rich individual heterogeneity. Our estimates show that advertising is effective in attracting healthy individuals who are newly eligible for Medicare, contributing to advantageous selection into Medicare Advantage. Moreover, risk selection through advertising substantially lowers premiums by improving insurers' risk pools. The distributional implication is that unhealthy consumers may be better off through cross-subsidization from healthy individuals.

Inhibitory effects of retigabine, a Kv7 channel activator, on mechanosensitive primary bladder afferent activities and nociceptive behaviors in rats.

AIMS: Kv7 voltage-gated potassium channels have been suggested to modulate mechano-afferent transduction and nociception in the bladder. We investigated the effects of retigabine, a Kv7 channel activator, on rhythmic bladder contractions (RBCs), and single-unit afferent activities (SAAs) of the primary bladder mechanosensitive afferent nerve fibers in urethane-anesthetized rats. In addition, the effects of pretreatment with retigabine on the nociceptive behaviors provoked by an intravesical instillation of resiniferatoxin (RTX) were evaluated in the conscious condition. METHODS: Female Sprague-Dawley rats were used. Under urethane anesthesia, saline was instilled into the bladder until RBCs were induced reproducibly. Then, the effects of intravenous, cumulative administrations of retigabine (0.1-3 mg/kg) or vehicle (saline) on RBCs were assessed. In separate animals, SAAs of Aδ- and C-fibers were identified by electrical stimulation of the pelvic nerve and by bladder distention with saline. After baseline recording, vehicle or retigabine (0.01-1 mg/kg) was administered intravenously and further recordings were performed. Under pretreatment with vehicle or retigabine (3 mg/kg intraperitoneally), the frequencies of lower abdominal licking and freezing were counted and scored as the bladder nociceptive behaviors induced by intravesical RTX instillation (3 µM, 0.3 ml). RESULTS: Retigabine dose-dependently decreased both the frequency and the amplitude of RBCs and SAAs of both Aδ- and C-fibers. The effect on RBCs was more potent on the frequency than the amplitude. Retigabine inhibited the RTX-induced abdominal licking, but not freezing. CONCLUSION: Kv7 channels are likely to be implicated in inhibition of bladder mechano- and nociceptive sensory transduction. Neurourol. Urodynam. 36:280-285, 2017. © 2015 Wiley Periodicals, Inc.

Ageing-related bladder functional and biological changes.

One of the major global demographic trends is the rapid ageing population, and the num- ber of people with ageing-related diseases has been increasing. In the urological field, ageing-related lower urinary tract symptoms (LUTS), especially detrusor hyperactivity with impaired contractility (DHIC), are commonly observed among elderly patients. However, such ageing-related LUTS and their backgrounds widely vary by individual. Previous reports using functional- and biological-investigations in rodents revealed the possible relationship between ageing and individual factors related to bladder function, which were hormonal fac- tors, intrinsic changes (fibrosis and denervation) and oxidative stress, etc. Here, I reviewed involvement of such factors on ageing-related LUTS including DHIC.

Preventive Effects of Long-Term Caloric Restriction on Aging Related In Vivo Bladder Dysfunction and Molecular Biological Changes in the Bladder and Dorsal Root Ganglia in Rats.

PURPOSE: We evaluated aging related bladder dysfunctions and biological changes in the bladder and dorsal root ganglia in rats. We also investigated whether long-term caloric restriction may have preventive effects on these changes. MATERIALS AND METHODS: Male Fischer 344 rats were divided into a young group (age 6 months) and an old group (age 25 to 28 months), each with free access to normal food, and an old group (age 25 to 28 months) with food restricted to 3 days per week. Conscious cystometry, cDNA microarray analysis, immunohistochemistry and oxidative stress measurements of the bladder and dorsal root ganglia were performed. RESULTS: The old group with free access to normal food showed higher threshold pressure, more nonvoiding contractions and lower bladder compliance than the young group with free access to food. Old rats with free access showed greater post-void residual volume and lower voiding efficiency than old rats with caloric restriction and young rats. In the old group with free access 83 genes in the bladder and 48 in the L6 dorsal root ganglia were up-regulated compared with old rats with caloric restriction and young rats. These genes were mostly related to immune and inflammatory responses. Immunohistochemistry showed stronger expression of the immune response protease Gzm (granzyme) B and the collagenase Mmp13 (matrix metalloproteinase-13) in the bladder of old rats with free access vs old rats with caloric restriction and young rats. The level of malondialdehyde, an oxidative stress marker, was higher in the bladder of old rats with free access than in young rats but there was no difference between old rats with caloric restriction and young rats with free access to food. CONCLUSIONS: In rats aging leads to storage and voiding dysfunctions associated with immune and inflammatory related responses in the bladder and dorsal root ganglia, and with increased oxidative stress in the bladder. Caloric restriction reduced these aging related changes.

Functional roles of bladder α1-adrenoceptors in the activation of single-unit primary bladder afferent activity in rats.

OBJECTIVES: To clarify the involvement of bladder α1-adrenoceptors (α1-ARs) in afferent pathways by investigating the effects of silodosin and BMY7378, selective α1A- or α1D-AR antagonists, respectively, on single-unit afferent nerve fibre activity (SAA) of the primary bladder afferent nerves and their relationship with bladder microcontractions in rats. MATERIALS AND METHODS: A total of 63 female Sprague-Dawley rats were anaesthetized with urethane. The SAA of Aδ and C fibres generated from the left L6 dorsal roots was determined using electrical stimulation of the left pelvic nerve and bladder distension. After measuring baseline SAA during constant filling cystometry, the procedure was repeated with i.v. (0.3-30 µg/kg) or intravesical (10 µm) administration of each antagonist. In separate rats, the bladder was filled with saline until the intravesical pressure reached 30 cmH2 O, and was kept under isovolumetric conditions, then the recording was performed with i.v.-administered vehicle and silodosin (0.3 µg/kg). RESULTS: A total of Aδ fibres and 33 C fibres were isolated from 63 rats. The SAA of Aδ fibres, but not C fibres, were dose-dependently decreased after both i.v. and intravesical administrations of each of the antagonists. In the experiments under bladder isovolumetric conditions, silodosin administration significantly decreased the SAA of Aδ fibres, but not C fibres, compared with vehicle administration. There were no significant effects on either the mean basal bladder pressure or microcontractions. CONCLUSION: The present study suggests that both α1A- or α1D-ARs in the rat bladder are involved in the activation of the bladder mechanosensory Aδ fibres during bladder filling, and that this activation may not be related to bladder microcontractions.

URB937, a peripherally restricted inhibitor for fatty acid amide hydrolase, reduces prostaglandin E2 -induced bladder overactivity and hyperactivity of bladder mechano-afferent nerve fibres in rats.

OBJECTIVE: To determine if inhibition of the endocannabinoid-degrading enzyme fatty acid amide hydrolase (FAAH) can counteract the changes in urodynamic variables and bladder afferent activities induced by intravesical prostaglandin E2 (PGE2 ) instillation in rats. MATERIALS AND METHODS: In female Sprague-Dawley rats we studied the effects of URB937, a peripherally restricted FAAH inhibitor, on single-unit afferent activity (SAA) during PGE2 -induced bladder overactivity (BO). SAA measurements were made in urethane-anaesthetised rats and Aδ- and C-fibres were identified by electrical stimulation of the pelvic nerve and by bladder distention. Cystometry (CMG) in conscious animals and during SAA measurements was performed during intravesical instillation of PGE2 (50 or 100 µm) after intravenous administration of URB937 (0.1 and 1 mg/kg) or vehicle. In separate experiments, the comparative expressions of FAAH and cannabinoid receptors, CB1 and CB2 , in microsurgically removed L6 dorsal root ganglion (DRG) were studied by immunofluorescence. RESULTS: During CMG, 1 mg/kg URB937, but not vehicle or 0.1 mg/kg URB937, counteracted the PGE2 -induced changes in urodynamic variables. PGE2 increased the SAAs of C-fibres, but not Aδ-fibres. URB937 (1 mg/kg) depressed Aδ-fibre SAA and abolished the facilitated C-fibre SAA induced by PGE2 . The DRG nerve cells showed strong staining for FAAH, CB1 and CB2 , with a mean (sem) of 77 (2)% and 87 (3)% of FAAH-positive nerve cell bodies co-expressing CB1 or CB2 immunofluorescence, respectively. CONCLUSION: The present results show that URB937, a peripherally restricted FAAH inhibitor, reduces BO and C-fibre hyperactivity in the rat bladder provoked by PGE2 , suggesting an important role of the peripheral endocannabinoid system in BO and hypersensitivity.

Functional role of the transient receptor potential melastatin 8 (TRPM8) ion channel in the urinary bladder assessed by conscious cystometry and ex vivo measurements of single-unit mechanosensitive bladder afferent activities in the rat.

OBJECTIVE: To evaluate the role of the transient receptor potential melastatin 8 (TRPM8) channel on bladder mechanosensory function by using L-menthol, a TRPM8 agonist, and RQ-00203078 (RQ), a selective TRPM8 antagonist. MATERIALS AND METHODS: Female Sprague-Dawley rats were used. In conscious cystometry (CMG), the effects of intravesical instillation of L-menthol (3 mm) were recorded after intravenous (i.v.) pretreatment with RQ (3 mg/kg) or vehicle. The direct effects of RQ on conscious CMG and deep body temperature were evaluated with cumulative i.v. administrations of RQ at 0.3, 1, and 3mg/kg. Single-unit mechanosensitive bladder afferent activities (SAAs) were monitored in a newly established ex vivo rat bladder model to avoid systemic influences of the drugs. Recordings were performed after cumulative intra-aortic administration of RQ (0.3 and 3 mg/kg) with or without intra-vesical L-menthol instillation (3 mm). RESULTS: Intravesical L-menthol decreased bladder capacity and voided volume, which was counteracted by RQ-pretreatment. RQ itself increased bladder capacity and voided volume, and lowered deep body temperature in a dose-dependent manner. RQ decreased mechanosensitive SAAs of C-fibres, and inhibited the activation of SAAs induced by intravesical L-menthol. CONCLUSION: Our results suggest that TRPM8 channels have a role in activation of bladder afferent pathways during filling of the bladder in the normal rat. This effect seems, at least partly, to be mediated via mechanosensitive C-fibres.