The influence of Rho-kinase inhibition on acetic acid-induced detrusor overactivity

The Assessment of the Efficacy of Imperatorin in Reducing Overactive Bladder Symptoms

Overactive bladder syndrome (OAB) is a prevalent condition that affects the elderly population in particular and significantly impairs quality of life. Imperatorin, a naturally occurring furocoumarin, possesses diverse pharmacological properties that warrant consideration for drug development. The aim of this study was to investigate the potential of imperatorin (IMP) to attenuate the cystometric and biochemical changes typically associated with retinyl acetate-induced overactive bladder (OAB) and to assess its viability as a pharmacological intervention for OAB patients. A total of 60 rats were divided into four groups: I-control, II-rats with rapamycin (RA)-induced OAB, III-rats administered IMP at a dose of 10 mg/kg/day, and IV-rats with RA-induced OAB treated with IMP. IMP or vehicle were injected intraperitoneally for 14 days. The cystometry and assessment of bladder blood flow were performed two days after the last dose of IMP. The rats were then placed in metabolic cages for 24 h. Urothelial thickness measurements and biochemical analyses were performed. Intravesical infusion of RA induced OAB. Notably, intraperitoneal administration of imperatorin had no discernible effect on urinary bladder function and micturition cycles in normal rats. IMP attenuated the severity of RA-induced OAB. RA induced increases in urothelial ATP, calcitonin gene-related peptide (CGRP), organic cation transporter 3 (OCT3), and vesicular acetylcholine transporter (VAChT), as well as significant c-Fos expression in all micturition areas analyzed, which were attenuated by IMP. Furthermore, elevated levels of Rho kinase (ROCK1) and VAChT were observed in the detrusor, which were reversed by IMP in the context of RA-induced OAB in the urothelium, detrusor muscle, and urine. Imperatorin has a mitigating effect on detrusor overactivity. The mechanisms of action of IMP in the bladder appear to be diverse and complex. These findings suggest that IMP may provide protection against RA-induced OAB and could potentially develop into an innovative therapeutic strategy for the treatment of OAB.

Enhanced RAGE Expression and Excess Reactive-Oxygen Species Production Mediates Rho Kinase-Dependent Detrusor Overactivity After Methylglyoxal Exposure

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound implicated in diabetes-associated diseases. In vascular tissues, MGO induces the formation of advanced glycation end products (AGEs) that bounds its receptor RAGE, initiating the downstream tissue injury. Outside the cardiovascular system, MGO intake produces mouse voiding dysfunction and bladder overactivity. We have sought that MGO-induced bladder overactivity is due to activation of AGE-RAGE-reactive-oxygen species (ROS) signaling cascade, leading to Rho kinase activation. Therefore, female mice received 0.5% MGO orally for 12 weeks, after which in vitro bladder contractions were evaluated in the presence or not of superoxide dismutase (PEG-SOD) or the Rho kinase inhibitor Y27632. Treatment with MGO significantly elevated the serum levels of MGO and fluorescent AGEs, as well as the RAGE immunostaining in the urothelium, detrusor, and vascular endothelium. RAGE mRNA expression in the bladder was also higher in the MGO group. Methylglyoxal significantly increased the ROS production in both urothelium and detrusor smooth muscle, with the increases in detrusor markedly higher than urothelium. The bladder activity of superoxide dismutase (SOD) was significantly reduced in the MGO group. Gene expressions of L-type Ca²⁺ channels, RhoA, ROCK-1, and ROCK-2 in bladder tissues were significantly elevated in the MGO group. Increased bladder contractions to electrical-field stimulation, carbachol α,β-methylene ATP, and extracellular Ca²⁺ were observed after MGO exposure, which was significantly reduced by prior incubation with either PEG-SOD or Y27632. Overall, our data indicate serum MGO accumulation elevates the AGEs levels and activates the RAGE-ROS signaling leading to Rho kinase-induced muscle sensitization, ultimately leading to detrusor overactivity.

Asiatic Acid, a Natural Compound that Exerts Beneficial Effects on the Cystometric and Biochemical Parameters in the Retinyl Acetate-Induced Model of Detrusor Overactivity

Scientists have been constantly looking for new synthetic and natural compounds that could have beneficial effects in bladder overactivity. Our attention was drawn by asiatic acid that influences a number of molecules and signaling pathways relevant for the proper functioning of the urinary tracts in humans. In the present project we wanted to check whether asiatic acid would have positive effects in the confirmed animal model of detrusor overactivity (DO) and whether it would affect the bladder blood flow, urothelium thickness, inflammatory and oxidative stress markers, neurotrophic and growth factors, and other parameters important for the activity of the urinary bladder. The outcomes of our study showed that a 14-day administration of asiatic acid (30 mg/kg/day) by oral gavage normalizes the cystometric parameters corresponding to DO and reduces the accompanying oxidative stress (measured by the levels of malondialdehyde-61,344 ± 24,908 pg/ml vs. 33,668 ± 5,071 pg/ml, 3-nitrotyrosine-64,615 ± 25,433 pg/ml vs. 6,563 ± 1,736 pg/ml, and NOS2-2,506 ± 411.7 vs. 3,824 ± 470.1 pg/ml). Moreover, it decreases the urinary secretion of neurotrophins (BDNF-304.4 ± 33.21 pg/ml vs. 119.3 ± 11.49 pg/ml and NGF-205.5 ± 18.50 vs. 109.7 ± 15.94 pg/ml) and prevents the changes in a range of biomarkers indicating the dysfunction of the urinary bladder, CGRP (421.1 ± 56.64 vs. 108.1 ± 11.73 pg/ml), E-Cadherin (773.5 ± 177.5 pg/ml vs. 1,560 ± 154.5 pg/ml), OCT3 (3,943 ± 814.6 vs. 1,018 ± 97.07 pg/ml), SNAP-23 (6,763 ± 808.9 pg/ml vs. 3,455 ± 554.5 pg/ml), SNAP-25 (2,038 ± 162.7 pg/ml vs. 833.3 ± 65.48), substance P (171.7 ± 16.86 pg/ml vs. 65.07 ± 8.250 pg/ml), SV2A (1,927 ± 175.3 pg/ml vs. 1,154 ± 254.9 pg/ml), tight junction protein 1 (360.1 ± 95.05 pg/ml vs. 563.4 ± 65.43 pg/ml), VAChT (16,470 ± 2,419 pg/ml vs. 7,072 ± 1,339 pg/ml), VEGFA (318.3 ± 37.89 pg/ml vs. 201.5 ± 22.91 pg/ml). The mentioned parameters are associated with smooth muscle contractions, urothelial barrier, transportation and release of transmitters, or bladder compensation. Thus, the presented findings allow to suggest a possible future role of asiatic acid in the prevention of conditions accompanied by DO, such as overactive bladder.

MicroRNA expression profile in the spinal cord injured rat neurogenic bladder by next-generation sequencing

Background

An increasing amount of evidence has indicated that microRNAs (miRs) are involved in most biological conditions, including the neurogenic bladder (NB). However, to our knowledge, no studies have investigated these miR expressions in spinal cord-injured (SCI) rat NB. The goal of the study was to explore the miR expression profile in the SCI rat NB by next-generation sequencing (NGS).

Methods

Female Wistar rats underwent spinal cord transection at T9–10 and were randomly divided into the SCI-1, SCI-2 and SCI-3 groups (n=5 for each group) whose bladder tissues were collected 1, 2, and 4 weeks after transection, respectively. The normal rats were used as the normal control (NC) group. MiRs microarray assays were used to detect the differentially expressed miRs between the groups by NGS, which was then verified by quantitative real-time polymerase chain reaction (qRT-PCR). Those significantly differently expressed miRs were analyzed with Gene Ontology categories and Kyoto Encyclopedia of Genes and Genomes bioinformatical analyses.

Results

Compared with the NC group, 96, 28 and 51 miRs were downregulated in the rats’ bladder in the SCI-1, SCI-2, and SCI-3 groups, respectively, and 133, 49, and 76 miRs were upregulated respectively. Specifically, miR-21-5p was the most significantly upregulated miR in all SCI groups. Also, 121 miRs (SCI-1 vs. SCI-2), 98 miRs (SCI-1 vs. SCI-3), and 26 miRs (SCI-2 vs. SCI-3) were of significantly different expression. Furthermore, a large set of genes implicated in essential signaling pathways were targeted by these miRs, including PI3K-Akt, MAPK, Rap1, and cGMP-PKG signaling pathways, along with the tight junction and metabolic pathways.

Conclusions

This is the first demonstration of differentially expressed miRs, which may potentially serve as new molecular targets in the SCI rat NB.

A Novel Alternative in the Treatment of Detrusor Overactivity? In Vivo Activity of O-1602, the Newly Synthesized Agonist of GPR55 and GPR18 Cannabinoid Receptors

The aim of the research was to assess the impact of O-1602—novel GPR55 and GPR18 agonist—in the rat model of detrusor overactivity (DO). Additionally, its effect on the level of specific biomarkers was examined. To stimulate DO, 0.75% retinyl acetate (RA) was administered to female rats’ bladders. O-1602, at a single dose of 0.25 mg/kg, was injected intra-arterially during conscious cystometry. Furthermore, heart rate, blood pressure, and urine production were monitored for 24 h, and the impact of O-1602 on the levels of specific biomarkers was evaluated. An exposure of the urothelium to RA changed cystometric parameters and enhanced the biomarker levels. O-1602 did not affect any of the examined cystometric parameters or levels of biomarkers in control rats. However, the O-1602 injection into animals with RA-induced DO ameliorated the symptoms of DO and caused a reversal in the described changes in the concentration of CGRP, OCT₃, BDNF, and NGF to the levels observed in the control, while the values of ERK1/2 and VAChT were significantly lowered compared with the RA-induced DO group, but were still statistically higher than in the control. O-1602 can improve DO, and may serve as a promising novel substance for the pharmacotherapy of bladder diseases.

The influence of nebivolol on the activity of BRL 37344 - the β3-adrenergic receptor agonist, in the animal model of detrusor overactivity

AIMS

The cardiotoxic effects of antimuscarinics constitute a significant restriction in their application in elderly people. Overactive bladder syndrome pharmacotherapy using compounds with cardioprotective properties would seem an ideal solution. The main goal of the study was to assess the impacts of nebivolol (NEB) on the activity of BRL 37344 - β3-adrenergic receptor (β3AR) agonist, in the animal model of detrusor overactivity. As both these substances can impact on the cardiovascular system, their effect on the parameters of this system and diuresis was also examined.

METHODS

Retinyl acetate (RA; 0.75%) solution was used to induce detrusor overactivity in female Wistar rats. BRL and/or NEB were administered intra-arterially during cystometry in a single dose (2.5 or 5, 0.05 or 0.1 mg/kg, respectively). In addition, a 24 hours measurement of heart rate, blood pressure, and urine production was carried out.

RESULTS

NEB (0.05 mg/kg) and BRL (2.5 mg/kg) monotherapy proved to have no influence on the cystometric parameters of animals with RA-induced detrusor overactivity. NEB at 0.1 mg/kg resulted in a drop in the detrusor overactivity index, similarly to BRL at 5 mg/kg. Coadministration of NEB and BRL, both at ineffective doses, decreased the detrusor overactivity index and ameliorated the nonvoiding contractions. β3AR stimulation proved to induce tachycardia and hypertension. NEB at 0.05 mg/kg proved to ameliorate detrusor overactivity and have preventive properties against adverse cardiovascular effects of the β3AR agonist.

CONCLUSIONS

The combined application of the β3AR agonist and NEB may improve detrusor overactivity without affecting the heart rate, blood pressure, and urine production.

Blebbistatin reveals beneficial effects on the cystometric parameters in an animal model of detrusor overactivity

The aims of the study were to determine the effectiveness of blebbistatin (BLEB) on detrusor overactivity (DO) in an animal model induced by retinyl acetate (RA) and, because of potential urothelial permeability, to evaluate the degenerative impact of BLEB on the urothelium. Three days after RA instillation into the urinary bladder, BLEB was administered into the bladder and immediately after cystometric assessment was performed. Furthermore, Evans Blue extravasation into bladder tissue and urothelium thickness were measured. Sixty female Wistar rats were used and randomly assigned to one of four groups (n = 15 in each group): (1) control, (2) RA, (3) BLEB, and (4) RA + BLEB. RA administration induced changes in cystometric parameters reflecting DO, as previously reported. Treatment with BLEB did not significantly alter cystometric parameters in rats which did not receive RA. Administration of BLEB to rats pretreated with RA reversed changes in cystometric parameters induced by RA in basal pressure, threshold pressure, detrusor overactivity index, amplitude of nonvoiding contractions, frequency of nonvoiding contractions, voided volume, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions. There were no significant differences in Evans Blue extravasation into bladder tissue or urothelium thickness between the groups. The current research provides new data on the possible utility of blebbistatin in the pharmacotherapy of DO, which is an important feature of overactive bladder (OAB). Further studies in human patients with DO/OAB are warranted to confirm these preclinical results.

The influence of duloxetine on detrusor overactivity in rats with depression induced by 13-cis-retinoic acid

INTRODUCTION AND HYPOTHESIS

The aim of this study was to assess the efficacy of duloxetine in an animal model of detrusor overactivity induced by depression.

METHODS

After 6 weeks of 13-cis-retinoic acid administration at a dose of 1 mg/kg/day, rats were given duloxetine at a dose of 1 mg/kg. This was followed by conscious cystometry, a forced swim test, and locomotor activity measurement. The levels of corticotropin-releasing factor (CRF) in the hypothalamus, amygdala and plasma were also determined.

RESULTS

Duloxetine treatment led to a reduction in detrusor overactivity symptoms induced by the retinoid. Decreases were observed in cystometric parameters including the detrusor overactivity index, and the amplitude and frequency of nonvoiding contractions, while increases were seen in bladder compliance and the volume threshold to elicit nonvoiding contractions. No statistically significant differences were found in basal pressure, threshold pressure, micturition voiding pressure, postvoid residual , volume threshold, voiding efficiency, intercontraction interval, bladder contraction duration or relaxation time. Duloxetine also reduced the immobility time to that observed in control animals, while it did not affect locomotor activity. Its effects also included lowering of the CRF levels in the hypothalamus, amygdala and plasma, which increased following the prior administration of the retinoid. The plasma level of 13-cis-retinoic acid in rats corresponded to the levels found in humans.

CONCLUSIONS

This is the first study showing the efficacy of duloxetine in an animal model of detrusor overactivity induced by depression. Further studies in patients with detrusor overactivity and coexisting depression are warranted to confirm these experimental results.

cAMP-dependent regulation of RhoA/Rho-kinase attenuates detrusor overactivity in a novel mouse experimental model

OBJECTIVE

To investigate detrusor function and cAMP activation as a possible target for detrusor overactivity in an experimental model lacking a key denitrosylation enzyme, S-nitrosoglutathione reductase (GSNOR).

MATERIALS AND METHODS

GSNOR-deficient (GSNOR^-/- ) (n = 30) and wild-type (WT) mice (n = 26) were treated for 7 days with the cAMP activator, colforsin (1 mg/kg), or vehicle intraperitoneally. Cystometric studies or molecular analyses of bladder specimens were performed. Bladder function indices and expression levels of proteins that regulate detrusor relaxation (nitric oxide synthase pathway) or contraction (RhoA/Rho-kinase pathway) and oxidative stress were assessed. For statistical analysis the Student's t-test and one-way analysis of variance were used.

RESULTS

GSNOR^-/- mice had significantly higher (P < 0.05) voiding and non-voiding contraction frequencies compared to WT mice (Cohen's effect size values d = 1.82 and 2.52, respectively). Colforsin normalised these abnormalities (Cohen's effect size values d = 1.85 and 1.28, respectively). Western blot analyses showed an up-regulation of the RhoA/Rho-kinase pathway reflected by significantly higher (P < 0.05) phosphorylated myosin phosphatase target subunit 1 (P-MYPT-1) expression in GSNOR^-/- mouse bladders, which was reversed by colforsin treatment. There was a higher level (P < 0.05) of gp91^phox expression in the bladders of GSNOR^-/- mice without significant change after colforsin treatment. Neuronal and endothelial nitric oxide synthase phosphorylation on Ser-1412 and Ser-1177, respectively, did not differ between GSNOR^-/- and WT mouse bladders irrespective of colforsin treatment.

CONCLUSION

Impaired denitrosylation is associated with detrusor overactivity, which is linked with upregulated RhoA/Rho-kinase signalling. Colforsin reverses physiological and molecular abnormalities. This study describes a novel model of detrusor overactivity and suggests a possible basis for its treatment.

Rho kinase inhibition ameliorates cyclophosphamide-induced cystitis in rats

Hemorrhagic cystitis often develops in patients treated with cyclophosphamide (CYP). Studies have indicated that Rho kinase (ROCK) inhibitors may suppress detrusor overactivity symptoms and possess anti-inflammatory properties. The aim of the present study was to investigate whether inhibition of ROCK reduces cystometric and histopathological changes associated with CYP-induced cystitis. The rats received GSK 269962, a ROCK inhibitor, at a dose of 30 mg/kg daily, or vehicle for 7 days. Then, acute chemical cystitis leading to bladder overactivity was induced by CYP injection (200 mg/kg i.p.). Following CYP injection, cystometric studies with physiological saline were performed. Moreover, bladder edema (by the Evans Blue dye leakage technique) and urothelium thickness were measured. CYP injection resulted in a significant increase in cystometric parameters: basal pressure, threshold pressure, bladder contraction duration, relaxation time, detrusor overactivity index, non-voiding contractions amplitude, and non-voiding contractions frequency as well as increased Evans Blue extravasation into bladder tissue, whereas micturition voiding pressure, voided volume, post-void residual, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit non-voiding contractions as well as urothelium thickness were significantly decreased in CYP-injected rats. Administration of GSK 269962 normalized the abovementioned CYP injection-induced changes. Inhibition of ROCK was found to ameliorate CYP-induced detrusor overactivity and bladder inflammation. Our data indicate uroprotective effects following ROCK inhibition, which further suggests that this strategy may become an interesting pharmacological tool to prevent urinary adverse effects in patients treated with chemotherapy using CYP.

Fourteen-day administration of corticosterone may induce detrusor overactivity symptoms

Introduction and hypothesis

Epidemiological studies demonstrated that patients suffering from overactive bladder often present with different mental problems, amongst which depression is the most frequently observed. The main goal of our study was to check if the repeated administration of corticosterone (CORT) is able to evoke the depressive-like behaviour and detrusor overactivity (DO) symptoms in rats. Moreover, we investigated whether the acute administration of common antidepressants (imipramine, 30 mg/kg, and fluoxetine, 15 mg/kg), antimuscarinic (oxybutynin chloride, 0.5 mg/kg) or CRF₁ (SN 003, 1 mg/kg) antagonists has an impact on the cystometric parameters, behaviour in the Porsolt test, and overall locomotor activity of animals exposed to CORT.

Methods

The experiments were carried out on female Wistar rats. All applied surgical and histopathology procedures, cystometric investigations, locomotor activity and forced swim measurements have been fully described in the published literature.

Results

Fourteen-day administration of CORT may induce both depressive and DO symptoms in rats, which are reversed by the inhibition of CRF₁ receptors.

Conclusions

It seems that the CRF₁ receptor could be an interesting target for overactive bladder pharmacotherapy, particularly in patients with co-existing depression.

An animal model of detrusor overactivity induced by depression

INTRODUCTION

Depression is frequently found in patients suffering from overactive bladder. The aim of the study was to verify whether the 13-cis-retinoic acid, a synthetic retinoid used in the treatment of acne, which was proven to induce depressive changes in both humans and animals, can cause detrusor overactivity symptoms in conscious rats.

METHODS

In order to assess the 13-cis-retinoic acid impact on the behavioural parameters, after 6weeks of intraperitoneal administration of retinoid in a dose of 1mg/kg/day, a forced swim test and cystometry were performed, and the locomotor activity of animals was assessed. The control group received a mixture of DMSO and physiological saline at a 1:1 ratio.

RESULTS

13-cis-retinoic acid caused cystometric parameter changes analogous to those observed in people with a urodynamic diagnosis of detrusor overactivity. The retinoid caused also an extension of the immobility time in the forced swim test which is consistent with increased depression-related behaviour, with no impact on the locomotor activity of rats. The intravenous administration of solifenacin succinate in a single dose of 0.03mg/kg turned out to reverse changes in the cystometric parameters modified by 13-cis-retinoic acid treatment. The histopathological analysis of bladders did not show any lesions in the upper layer of the umbrella cells, urothelium or muscles. The retinoid concentration level achieved in the animals tested turned out to be identical to that occurring in humans.

DISCUSSION

13-cis-retinoic acid can induce detrusor overactivity symptoms that are reversed by solifenacin succinate.

Ovariectomy May Induce Detrusor Overactivity in Rats: The Therapeutic Role of Rho Kinase Inhibition

OBJECTIVE

To verify the impact of ovariectomy (OVX) on the micturition cycle in conscious rats; to examine the influence of rho kinase (ROCK) inhibition on the bladder detrusor in OVX rats; to assess the effect of the joint administration of the ROCK inhibitor (GSK 269962) and solifenacin succinate (SOL) to these animals.

MATERIALS AND METHODS

The impact of OVX or a single dose of GSK 269962 and/or SOL on the cystometric parameters was assessed 28 days after the procedure.

RESULTS

OVX caused an increase in detrusor overactivity index, amplitude, and frequency of nonvoiding contractions, along with a decrease in voided volume, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions. GSK 269962 administered in a dose of 10 mg/kg (but not 5 mg/kg) or SOL in a dose of 0.03 mg/kg (but not 0.015 mg/kg) triggered an increase in voided volume, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions, along with a decrease in detrusor overactivity index, amplitude, and frequency of nonvoiding contractions. A combined administration of GSK 269962 (5 mg/kg) and SOL (0.15 mg/kg), in doses ineffective in monotherapy, triggered a reversal in the OVX-induced cystometric changes.

CONCLUSION

It appears that ROCK inhibitors can become an alternative worth considering in overactive bladder syndrome treatment, especially in the light of the findings pointing to the decreased efficiency of antimuscarinic drugs in the overactive bladder syndrome treatment of postmenopausal women.