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.

Functional urological disorders: a sensitized defence response in the bladder-gut-brain axis

Functional urological and gastrointestinal disorders are interrelated and characterized by a chronic course and considerable treatment resistance. Urological disorders associated with a sizeable functional effect include overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Poor treatment outcomes might be attributable to untreated underlying psychological and psychiatric disorders, as the co-occurrence of functional urological and gastrointestinal disorders with mood and anxiety disorders is common. The hypothetical bladder-gut-brain axis (BGBA) is a useful framework under which this interaction can be studied, suggesting that functional disorders represent a sensitized response to earlier threats such as childhood adversity or previous traumatic events, resulting in perceived emotional and bodily distress - the symptoms of functional disorders. Psychological and physical stress pathways might contribute to such alarm falsification, and neuroticism could be a risk factor for the co-occurrence of functional disorders and affective conditions. Additionally, physical threat - either from external sources or internal sources such as infection - might contribute to alarm falsification by influencing body-brain crosstalk on homeostasis and, therefore, affecting mood, cognition, and behaviour. Multidisciplinary research and an integrated care approach is, therefore, required to further elucidate and remediate functional urological and gastrointestinal polymorphic phenotypes.

Nonsurgical Treatment of Urinary Incontinence in Elderly Women

Urinary incontinence is a prevalent condition in elderly women with significant associated morbidity. Incontinence can by grouped into several types: stress incontinence, urgency incontinence, overflow incontinence, functional incontinence, and mixed urinary incontinence. Careful evaluation, including history and physical examination, is critical to making the correct diagnosis and guiding therapy. A variety of nonsurgical treatments, including behavioral therapies, pelvic floor muscle exercise, medications, and other treatments, are available; can be successful for many older women; and may preclude the need for surgery. Working closely with the patient, understanding her goals of care, and targeting treatments accordingly are essential for success.

The Ameliorating Effect of Exogenous Melatonin on Urinary Bladder Function in Hyperosmolar Bladder Overactivity and its Influence on the Autonomic Nervous System Activity

This study was designed to investigate the effects of melatonin on the bladder hyperactivity in hyperosmolar-induced overactive bladder (OAB) rats. Additionally, the influence of melatonin on the autonomic nervous system (ANS) using heart rate variability (HRV) analysis was assessed. 40 rats were divided into four groups: I – control (n=12), II – rats with hyperosmolar OAB (n=6), III – rats with melatonin pretreatment and hyperosmolar OAB (n=6) and IV – control with melatonin pretreatment (n=6). In group III and IV melatonin in dose of 100 mg/kg was given. HRV measurements in 10 rats, as follow: control (n=2), control after melatonin treatment (n=2), rats with hyperosmolar OAB without (n=3), and after (n=3) melatonin treatment were conducted. This study demonstrates marked influence of melatonin on urinary bladder activity in hyperosmolar-induced OAB rats. These rats showed significantly reduced the detrusor motor overactivity resulting in the improvement of cystometric parameters after melatonin treatment when compared to the control, as follow: a significant increase of intercontraction interval (70 %) and functional bladder capacity (67 %), as well as a decrease of the basal pressure, detrusor overactivity index and motility index of 96 %, 439 % and 40 %, respectively. ANS activity analysis revealed sympathetic overactivity in OAB rats, and parasympathetic superiority in melatonin treated OAB rats. Melatonin treatment in rats with hyperosmolar OAB (group III) caused significant increase of nuHF parameter (from 51.00 ± 25.29 to 76.97 ± 17.43), as well as a decrease of nuLF parameter (from 49.01 ± 25.26 to 23.03 ± 17.43) and LF/HF ratio (from 1.280 ± 0.980 to 0.350 ± 0.330). In conclusion, melatonin suppresses hyperosmolar OAB, and modulates ANS activity by inhibition of the sympathetic drive. Therefore, melatonin may become a useful agent for OAB management.

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.

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

AIMS

Accumulating evidence has shown that Rho-kinase (ROCK) is involved in the regulation of bladder contraction. Our objective was to examine whether the ROCK inhibitor, GSK 269962, could prevent acetic acid (AA)-induced detrusor overactivity and to assess its influence on urine production (UP) and mean arterial pressure (MAP).

METHODS

The bladder was catheterized from the external urethral orifice. 0.25 % (AA) solution was infused into the bladder for 5 min. In the same session a catheter was inserted into the apex of the bladder dome. In order to measure the blood pressure, the carotid artery was cannulated. Three days after the intravesical instillation of AA, the ROCK-GSK 269962 inhibitor was administered in a single dose of 10 mg/kg and a cystometry was carried out, along with a 24 hr measurement of UP and MAP.

RESULTS

GSK 269962 reversed the changes induced by AA causing a drop in basal pressure, threshold pressure, micturition voiding pressure, bladder contraction duration, relaxation time, detrusor overactivity index, amplitude, and frequency of nonvoiding contractions while an increase in voided volume, post-void residual, volume threshold, voiding efficiency, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions. ROCK inhibition did not show any significant changes in UP and MAP.

DISCUSSION

The results obtained indicate that ROCK inhibition may ameliorate AA-induced bladder overactivity.

CONCLUSION

ROCK inhibitors appear to represent a potentially attractive pharmacological option for the treatment of lower urinary tract disorders associated with changes in detrusor contractility. Neurourol. Urodynam. 36:263-270, 2017. © 2015 Wiley Periodicals, Inc.

Increased urothelial paracellular transport promotes cystitis

Changes in the urothelial barrier are observed in patients with cystitis, but whether this leads to inflammation or occurs in response to it is currently unknown. To determine whether urothelial barrier dysfunction is sufficient to promote cystitis, we employed in situ adenoviral transduction to selectively overexpress the pore-forming tight junction-associated protein claudin-2 (CLDN-2). As expected, the expression of CLDN-2 in the umbrella cells increased the permeability of the paracellular route toward ions, but not to large organic molecules. In vivo studies of bladder function revealed higher intravesical basal pressures, reduced compliance, and increased voiding frequency in rats transduced with CLDN-2 vs. controls transduced with green fluorescent protein. While the integrity of the urothelial barrier was preserved in the rats transduced with CLDN-2, we found that the expression of this protein in the umbrella cells initiated an inflammatory process in the urinary bladder characterized by edema and the presence of a lymphocytic infiltrate. Taken together, these results are consistent with the notion that urothelial barrier dysfunction may be sufficient to trigger bladder inflammation and to alter bladder function.

The role of the peripheral cannabinoid system in the pathogenesis of detrusor overactivity evoked by increased intravesical osmolarity in rats

The cannabinoid receptors CB1 and CB2 are localized in the urinary bladder and play a role in the regulation of its function. We investigated the pathomechanisms through which hyperosmolarity induces detrusor overactivity (DO). We compared urinary bladder activity in response to blockade of CB1 and CB2 receptors using AM281 and AM630, respectively, in normal rats and after hyperosmolar stimulation. Experiments were performed on 44 rats. DO was induced by intravesical instillation of hyperosmolar saline. Surgical procedures and cystometry were performed under urethane anaesthesia. The measurements represent the average of 5 bladder micturition cycles. We analysed basal, threshold, and micturition voiding pressure; intercontraction interval; compliance; functional bladder capacity; motility index; and detrusor overactivity index. The blockage of CB1 and CB2 receptors diminished the severity of hyperosmolar-induced DO. In comparison with naïve animals the increased frequency of voiding with no significant effect on intravesical voiding pressure profile was observed as a result of the blockage of CB1 and CB2 receptors. These results demonstrate that hyperosmolar-induced DO is mediated by CB1 and CB2 receptors. Therefore, the cannabinoid pathway could potentially be a target for the treatment of urinary bladder dysfunction.

Purinergic signalling in the urinary tract in health and disease

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

The effect of hyperosmolar stimuli and cyclophosphamide on the culture of normal rat urothelial cells in vitro

Highly concentrated urine may induce a harmful effect on the urinary bladder. Therefore, we considered osmolarity of the urine as a basic pathomechanism of mucosal damage. The influence of both cyclophosphamide (CYP) and hyperosmolar stimuli (HS) on the urothelium are not well described. The purpose was to evaluate the effect of CYP and HS on rat urothelial cultured cells (RUCC). 15 Wistar rats were used for RUCC preparation. RUCC were exposed to HS (2080 and 3222 mOsm/l NaCl) for 15 min and CYP (1 mg/ml) for 4 hrs. APC-labelled annexin V was used to quantitatively determine the percentage of apoptotic cells and propidium iodide (PI) as a standard flow cytometric viability probe to distinguish necrotic cells from viable ones. Annexin V-APC (+), annexin V-APC and PI (+), and PI (+) cells were analysed as apoptotic, dead, and necrotic cells, respectively. The results were presented in percentage values. The flow cytometric analysis was done on a FACSCalibur Flow Cytometer using Cell-Quest software. Treatment with 2080 and 3222 mOsm/l HS resulted in 23.7 ± 3.9% and 26.0 ± 1.5% apoptotic cells, respectively, 14.3 ± 1.4% and 19.4 ± 2.7% necrotic cells, respectively and 60.5 ± 1.4% and 48.6 ± 5.3% dead cells, respectively. The effect of CYP on RUCC was similar to the effect of HS. After CYP the apoptotic and necrotic cells were 23.1 ± 0.3% and 17.9 ± 7.4%, respectively. The percentage of dead cells was 57.7 ± 10.8%. CYP and HS induced apoptosis and necrosis in RUCC. 3222 mOsm/l HS had the most harmful effect based on the percentage of necrotic and apoptotic cells.

Effect of hyaluronic acid on urine nerve growth factor in cyclophosphamide-induced cystitis

OBJECTIVES

To investigate how hyaluronic acid (HA) affects nerve growth factor (NGF) production and bladder overactivity in a cyclophosphamide (CYP)-induced cystitis rat model.

METHODS

Female Sprague-Dawley rats received three intermittent intraperitoneal injections of CYP (75 mg/kg) or saline. Before or after CYP injection, HA was given intravesically and urine NGF was checked with creatinine correction. Bladder function was evaluated by cystometrograms under Zoletil anesthesia. Furthermore, the effect of HA was counteracted with hyaluronidase (HYAL). Bladder structural change was compared among groups with trichrome stain.

RESULTS

The intercontraction interval (ICI) significantly decreased in CYP-injected rats in comparison to the saline-injected controls. In the CYP-injected groups, bladder HA instillation significantly increased the ICI, but did not change the maximum voiding pressure in comparison to the saline instillation. NGF production significantly increased in CYP-injected rats, but decreased significantly with HA treatment. Treatment with HA had a more significant effect on urine NGF and the use of HYAL would eliminate this effect. Specific staining showed mucosa swelling after CYP treatment. Little HA coating on bladder mucosa could be found in HA-treated rats.

CONCLUSIONS

Present findings raise the possibility that HA could be an effective treatment for CYP-related bladder overactivity through the involvement of NGF signaling.