Rho-kinase and effects of Rho-kinase inhibition on the lower urinary tract

Silencing of Rac1 and Arf6 reduces time-dependent and carbachol-induced contractions, proliferation, survival and growth in human bladder smooth muscle cells

PURPOSE

Storage symptoms in overactive bladder are explained by detrusor contractions and bladder wall thickening. Arf6 and Rac1 are monomeric GTPases with newly emerging roles in smooth muscle contraction and proliferation. Here, we investigated human bladder smooth muscle cells (hBSMC) functions after silencing of Arf6 or Rac1.

METHODS

hBSMC were transfected with Arf6- or Rac1-specific or scrambled siRNA (controls), and characterized using collagen contraction assays, for proliferation (EdU, Ki67), viability, growth in colony formation assays and actin organization.

RESULTS

Arf6 and Rac1 silencing was confirmed by RT-PCR. Time-dependent contractions (0.5-6 h after assay initiation) were reduced in Arf6- and Rac1-silenced cells (36% Arf6, 28% Rac1, after 6 h), compared to scramble-transfected cells. Carbachol (3 µM) increased the time-dependent contractions, which were reduced by silencing of Arf6 (40-62%, 0.5-6 h) or Rac1 (30-59% at 0.5-6 h). With U46619 or endothelin-1, time-dependent contractions were similar to contractions without agonists, but again reduced in Arf6- and Rac1-silenced cells. Compared to scramble-transfected cells, silencing reduced the proliferation rate (Arf6 52%, Rac1 33%), Ki67 mRNA expression (89%, 91%), colony formation (63%, 66%), viability (Arf6 up to 84%, Rac1 up to 85%), and actin polymerization (30%, 31%).

CONCLUSIONS

Arf6 and Rac1 promote time-dependent and carbachol-induced contractions of hBSMC, which may be mediated by actin polymerization. Simultaneously, Arf6 and Rac1 promote proliferation, growth and survival in hBSMC. Arf6 and Rac1 may be potentially involved in detrusor overactivity, bladder wall thickening and medical treatment of overactive bladder.

Association between metabolic syndrome and benign prostatic hyperplasia: The underlying molecular connection

Benign prostatic hyperplasia (BPH), a common cause of lower urinary tract symptoms (LUTS), has been recently regarded as a metabolic disease. Metabolic syndrome (MetS) is a constellation of metabolic disarrangements, including insulin resistance, obesity, hypertension, and dyslipidemia, and it has been established that these components of MetS are important contributing factors exacerbating the degree of prostatic enlargement and bladder outlet obstruction among patients with BPH. Clinical and experimental studies demonstrated that many molecules, such as insulin, insulin-like growth factor 1 (IGF-1), androgen and estrogen, and adipokines, are involved in the overlapping pathogenesis of BPH and MetS, indicating that clinicians might be able to simultaneously alleviate or cure two diseases by choosing appropriate medications. This article aims to systematically review the pathophysiological aspect and traditional etiology and pathogenesis of BPH and discuss the intricate association between MetS and BPH from the molecular point of view, in an attempt to provide stronger evidence for better treatment of two diseases.

Testosterone and aging male, a perspective from a developing country

PURPOSE

Hypogonadism is associated with a wide range of physical and psychological symptoms that can affect the overall health of men. However, in a developing country, there are several imposing challenges in the diagnosis and treatment of hypogonadism, including a lack of awareness and understanding of the condition among healthcare providers and patients, limited resources and the high cost of treatment. This review aimed to examine the potential benefits and risks of testosterone replacement therapy (TRT) and provides a perspective of a developing country on the topic.

MATERIALS AND METHODS

A comprehensive literature review was conducted to gather relevant information on the impact of testosterone deficiency on ageing males and the effectiveness of TRT for treating hypogonadism. Published peer-reviewed articles were analyzed to evaluate the benefits and risks of TRT. Additionally, the unique challenges faced in the diagnosis and treatment of hypogonadism in a developing country were considered.

RESULTS

Testosterone replacement therapy has been shown to be an effective treatment for hypogonadism, particularly in symptomatic men with low testosterone levels. It offers potential benefits such as improvements in symptoms and overall quality of life. However, there are associated risks and side effects that need to be considered. In a developing country, challenges such as limited awareness and understanding of hypogonadism, resource constraints, and high treatment costs pose additional barriers to accessing TRT and comprehensive care.

CONCLUSION

In conclusion, TRT holds promise as a treatment for hypogonadism, but its implementation and accessibility face significant challenges in a developing country. Addressing these challenges, including raising awareness, allocating resources, and finding cost-effective solutions, is crucial for ensuring that men with hypogonadism in such settings receive appropriate diagnosis and treatment. Further research and efforts are needed to improve the management of hypogonadism in developing countries and optimize the potential benefits of TRT for affected individuals.

Ageing influences detrusor contractions to prostaglandin, angiotensin, histamine and 5-HT (serotonin), independent to the Rho kinase and extracellular calcium pathways

Ageing is associated with deteriorating urinary bladder function and an increasing prevalence of disorders such as underactive bladder. There are suggestions that G protein-coupled receptor (GPCR) second messenger pathways are altered during ageing, rather than the receptor proteins themselves. The aim of this study was to identify age-related variations in GPCR activation systems in urinary bladder smooth muscle (detrusor). Isolated porcine detrusor strips were mounted in organ baths and contractile responses induced by receptor agonists were assessed and compared between juvenile (6 months) and adult (2 years) animals. The effects of drugs disrupting intracellular calcium signalling were also studied. Adult tissue was far more sensitive to stimulation by 5-hydroxytryptamine (42% greater increase than juvenile), prostaglandin-E2 (26% greater increase), and angiotensin-II (39% greater increase), however less sensitive to histamine. Although nifedipine and Y-27632 impacted the contraction to all agonists, there were no significant differences between juvenile and adult detrusor. Impairment of IP3-mediated calcium release by 2-aminoethyl diphenylborinate had no effect on any contractile activity, except for neurokinin-A which inhibited both juvenile and adult detrusor, and prostaglandin-E2 which inhibited juvenile. Carbachol, histamine, 5-hydroxytryptamine, and angiotensin-II were not affected by the application of 2-aminoethyl diphenylborinate. In conclusion, the contractile responses to all the GPCR agonists involved extracellular calcium influx and calcium sensitisation, but for prostaglandin-E2 the dependence on calcium from intracellular sources was greater in the younger animals.

Acetyl-L-carnitine improves erectile function in bilateral cavernous nerve injury rats via promoting cavernous nerve regeneration

BACKGROUND

Neurogenic erectile dysfunction (NED) caused by cavernous nerve (CN) injury is a typical complication after pelvic surgery, which lacks efficient treatments. Acetyl-L-carnitine (ALCAR) has been proven to promote nerve repair.

OBJECTIVES

To investigate the effect and potential mechanism of ALCAR in the treatment of NED.

MATERIALS AND METHODS

Thirty-two rats were randomly divided into bilateral cavernous nerve injury (BCNI) group, BCNI + lower-dose ALCAR (50 mg/kg/day) group, BCNI + higher-dose (100 mg/kg/day) group and sham-operated group. Erectile function was assessed 14 days after daily intraperitoneal injection of ALCAR or placebo. The penile tissues were gathered for subsequent histological and molecular biological analysis. Rat Schwann cell (SC) line S16 was used to verify the mechanism of ALCAR in vitro.

RESULTS

We found that the erectile function of the rats in BCNI group was severely impaired, which was improved considerably in both BCNI+ALCAR-LD and BCNI+ALCAR-HD groups. Also, we observed decreased smooth muscle and increased collagen content in corpus cavernosum in BCNI group. The expressions of fibrosis markers TGF-β, CTGF, and Smad 2/3 were significantly up-regulated in the BCNI group. The above changes were alleviated after the administration of lower and higher-dose ALCAR. Meanwhile, the NO/cGMP pathway was promoted and the RhoA/ROCK pathway was inhibited in the corpus cavernosum of BCNI rats after ALCAR treatment, accompanied by increased nNOS and down-regulated Tyrosine Hydroxylase. In vitro, ALCAR promoted the migration and proliferation of SC, and increased the expression of Pmp22 and NGF. Further, rats treated with ALCAR had high expression of ATF3 and S100 in the distal nerve tissues of the CN extrusion site.

DISCUSSION AND CONCLUSION

ALCAR could promote nerve repair and regeneration, inhibit penile fibrosis and improve penile erection by promoting the proliferation and migration of SC and the secretion of NGF. Our study confirms that ALCAR may be a potential treatment strategy for NED. This article is protected by copyright. All rights reserved.

The effect of vitamin D deficiency in children with overactive bladder related urinary incontinence

Purpose:

Overactive bladder (OAB) is a common syndrome associated with lower urinary tract symptoms (LUTS), especially urinary incontinence in children, which may affect the patient's quality of life (QoL). Vitamin D deficiency has been shown to be associated with OAB syndrome. This study evaluated the relationship between vitamin D status and OAB-related symptoms and QoL in children.

Materials and Methods:

The study included 52 pediatric patients with OAB-related urinary incontinence and 41 healthy children. LUTS were assessed using the Dysfunctional Voiding and Incontinence Symptoms Score (DVISS) questionnaire, and QoL was assessed using the Pediatric Incontinence Questionnaire (PINQ). Oral vitamin D supplementation was given to patients with OAB with vitamin D deficiency. Urinary symptoms and QoL were evaluated before and after vitamin D supplementation.

Results:

Vitamin D deficiency was more common in the OAB group (75%) than in the control group (36.6%). Logistic regression analysis revealed that vitamin D status (<20ng/mL) was a significant predictor of OAB. Both pre-treatment and post-treatment DVISS and PINQ scores showed a positive correlation. After vitamin D supplementation, 8 (23.5%) patients had a complete response and 19 (55.9%) patients had a partial response. Significant improvement in QoL was also achieved.

Conclusions:

Vitamin D deficiency is more common in children with urinary incontinence and OAB than in healthy children. Although vitamin D deficiency is not routinely evaluated for every patient, it should be evaluated in treatment-resistant OAB cases. Vitamin D supplementation may improve urinary symptoms and QoL in patients with OAB.

Inhibition of human prostate smooth muscle contraction by the inhibitors of protein kinase C, GF109203X, and Go6983

INTRODUCTION

Prostate smooth muscle contraction is promoted by receptor-induced activation of intracellular signaling pathways. The presumed involvement in etiology and medical treatment of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) imparts a high clinical relevance to prostate smooth muscle contraction, which is contrasted by incomplete understanding at the molecular level. Involvement of protein kinase C (PKC) has been commonly assumed, but available studies were limited to nonhuman prostate smooth muscle or cell cultures. Here, we examined the effects of the PKC inhibitors Go6983 and GF109203x on contractions of human prostate tissues.

METHODS

Prostate tissues were obtained from radical prostatectomy. Contractions were induced by electric field stimulation (EFS), α₁ -adrenergic agonists (noradrenaline, phenylephrine, methoxamine), thromboxane A₂ analog U46619, endothelin-1, or calcium chloride in an organ bath.

RESULTS

GF109203X (500 nM) and Go6983 (300  nM) reduced EFS-, noradrenaline-, phenylephrine-, methoxamine-, and U46619-induced contractions of human prostate tissues, with maximum inhibitions approaching up to 55%. Using concentrations of 3 µM, GF109203X and Go6983 inhibited EFS- and noradrenaline-induced contractions, with similar effect sizes as 500 and 300 nM, respectively. Endothelin-1-induced contractions were not inhibited by GF109203X, and to neglectable extent by Go6983. After depolarization in calcium-free solution, calcium chloride-induced concentration-dependent contractions, which were inhibited by GF109203X and Go6983.

CONCLUSIONS

GF109203X and Go6983 inhibit neurogenic, α₁ -adrenergic, and thromboxane A₂ -induced smooth muscle contractions in the human prostate, suggesting a role of PKC for human prostate smooth muscle contraction. The inhibition may by be imparted by inhibition of calcium sensitivity.

Diagnosis of chronic prostatitis by noninvasive methods in elderly patients with benign prostatic hyperplasia in China

Chronic prostatitis is hard to be identified in BPH patients in clinical works. This study aimed to diagnose chronic prostatitis in BPH patients by noninvasive methods. BPH patients who received transurethral resection of prostate from January 2014 to July 2015 were enrolled in current study. Patients were received examinations of PSA, sex hormones, inflammatory cytokines, metabolic panel and transrectal ultrasonography. According to histological results, patients were divided into two group of BPH with/without prostatitis. Logistic regression was used to find risk factors of chronic prostatitis. As a result, 181 men with an average age of 72.15 ± 8.41 years were enrolled in this study, including 116 patients with prostatitis and 65 patients without prostatitis. The storage sub-score, PSA and IL-2R were significantly higher in patients with prostatitis than those without prostatitis. Based on logistic regression analysis, the above three parameters were also the risk factors of BPH with prostatitis. The diagnostic model was calculated as: 0.317 × storage sub-score + 0.092 × PSA + 0.003 × IL-2R - 4.296. The AUC was 0.725. Histological prostatitis in BPH patients can be diagnosed by the combination of serum IL-2R, PSA and storage sub-score. Identification of chronic prostatitis in BPH patients could more efficiently alleviate urinary symptoms and reduce the risk of disease progression.

Deleterious impact of nerve growth factor precursor (proNGF) on bladder urothelial and smooth muscle cells

The nerve growth factor precursor (proNGF) activates p75^NTR receptor and promotes cell death in different tissues, yet this pathophysiological effect is not fully described in the bladder. The aim of this study was to identify the biological effect of proNGF/p75^NTR activation on urothelial and smooth muscle (SM) cells of rodents' bladder. Cell viability was assessed by MTT assay which showed a significant reduction in urothelial viability after 24 h of incubation with proNGF in culture medium [5 or 10 nM], an effect not seen in SM cells. Western blot analysis on cellular protein extracts showed increased expression of the transmembrane TNF-α and activation of RhoA in urothelial cells exposed to proNGF with no evidence of a nuclear translocation of NF-κB assessed by western blotting on nuclear extracts and immunofluorescence. The activation of p75^NTR-death domain related pathways in urothelial cells such as TNF-α or RhoA had a downstream effect on NO release and the junctional protein occludin, as estimated respectively by colorimetric and western blotting. On the other hand, proNGF did not induce TNF-α or RhoA expression in SM cells, but induced a significant NF-κB nuclear translocation. ProNGF had a different impact on SM as evidenced by a significant dose- and time-dependent increase in SM proliferation and migration examined by MTT test and cell migration assay. Together, our results indicate that activation of proNGF/p75^NTR axis induces degenerative changes to the urothelial layer impacting its barrier and signaling integrity, while promoting adaptive proliferative changes in detrusor SM cells that can interfere with the contractile phenotype essential for proper bladder function.

Regulation of smooth muscle contraction by monomeric non-RhoA GTPases

Smooth muscle contraction in the cardiovascular system, airways, prostate and lower urinary tract is involved in the pathophysiology of many diseases, including cardiovascular and obstructive lung disease plus lower urinary tract symptoms, which are associated with high prevalence of morbidity and mortality. This prominent clinical role of smooth muscle tone has led to the molecular mechanisms involved being subjected to extensive research. In general smooth muscle contraction is promoted by three major signalling pathways, including the monomeric GTPase RhoA pathway. However, emerging evidence suggests that monomeric GTPases other than RhoA may be involved in signal transduction in smooth muscle contraction, including Rac GTPases, cell division control protein 42 homologue, adenosine ribosylation factor 6, Ras, Rap1b and Rab GTPases. Here, we review these emerging functions of non-RhoA GTPases in smooth muscle contraction, which has now become increasingly more evident and constitutes an emerging and innovative research area of high clinical relevance.

Inhibition of Female and Male Human Detrusor Smooth Muscle Contraction by the Rac Inhibitors EHT1864 and NSC23766

Introduction

Lower urinary tract symptoms (LUTS) due to overactive bladder (OAB) are caused by spontaneous detrusor contractions. Medical treatment with muscarinic receptor antagonists or β₃-adrenoceptor agonists aims to inhibit detrusor contractions, but overall results are unsatisfactory. Consequently, improved understanding of bladder smooth muscle contraction and identification of novel compounds for its inhibition are needed to develop alternative options. A role of the GTPase Rac1 for smooth muscle contraction has been reported from the prostate, but is unknown in the human detrusor. Here, we examined effects of the Rac inhibitors NSC23766, which may also antagonize muscarinic receptors, and EHT1864 on contraction of human detrusor tissues.

Methods

Female and male human detrusor tissues were obtained from radical cystectomy. Effects of NSC23766 (100 µM) and EHT1864 (100 µM) on detrusor contractions were studied in an organ bath.

Results

Electric field stimulation induced frequency-dependent contractions of detrusor tissues, which were inhibited by NSC23766 and EHT1864. Carbachol induced concentration-dependent contractions. Concentration response curves for carbachol were shifted to the right by NSC23766, reflected by increased EC₅₀ values, but unchanged E_max values. EHT1864 reduced carbachol-induced contractions, resulting in reduced E_max values for carbachol. The thromboxane analog U46619 induced concentration-dependent contractions, which remained unchanged by NSC23766, but were reduced by EHT1864.

Conclusions

NSC23766 and EHT1864 inhibit female and male human detrusor contractions. NSC23766, but not EHT1864 competitively antagonizes muscarinic receptors. In addition to neurogenic and cholinergic contractions, EHT1864 inhibits thromboxane A₂-induced detrusor contractions. The latter may be promising, as the origin of spontaneous detrusor contractions in OAB is noncholinergic. In vivo, both compounds may improve OAB-related LUTS.

NK2 receptor-mediated detrusor muscle contraction involves Gq/11-dependent activation of voltage-dependent Ca2+ channels and the RhoA-Rho kinase pathway

Tachykinins (TKs) are involved in both the physiological regulation of urinary bladder functions and development of overactive bladder syndrome. The aim of the present study was to investigate the signal transduction pathways of TKs in the detrusor muscle to provide potential pharmacological targets for the treatment of bladder dysfunctions related to enhanced TK production. Contraction force, intracellular Ca²⁺ concentration, and RhoA activity were measured in the mouse urinary bladder smooth muscle (UBSM). TKs and the NK2 receptor (NK2R)-specific agonist [β-Ala⁸]-NKA(4-10) evoked contraction, which was inhibited by the NKR2 antagonist MEN10376. In Gα_q/11-deficient mice, [β-Ala⁸]-NKA(4-10)-induced contraction and the intracellular Ca²⁺ concentration increase were abolished. Although G_q/11 proteins are linked principally to phospholipase Cβ and inositol trisphosphate-mediated Ca²⁺ release from intracellular stores, we found that phospholipase Cβ inhibition and sarcoplasmic reticulum Ca²⁺ depletion failed to have any effect on contraction induced by [β-Ala⁸]-NKA(4-10). In contrast, lack of extracellular Ca²⁺ or blockade of voltage-dependent Ca²⁺ channels (VDCCs) suppressed contraction. Furthermore, [β-Ala⁸]-NKA(4-10) increased RhoA activity in the UBSM in a G_q/11-dependent manner and inhibition of Rho kinase with Y-27632 decreased contraction force, whereas the combination of Y-27632 with either VDCC blockade or depletion of extracellular Ca²⁺ resulted in complete inhibition of [β-Ala⁸]-NKA(4-10)-induced contractions. In summary, our results indicate that NK2Rs are linked exclusively to G_q/11 proteins in the UBSM and that the intracellular signaling involves the simultaneous activation of VDCC and the RhoA-Rho kinase pathway. These findings may help to identify potential therapeutic targets of bladder dysfunctions related to upregulation of TKs.

A NAV2729-sensitive mechanism promotes adrenergic smooth muscle contraction and growth of stromal cells in the human prostate

Voiding symptoms in benign prostatic hyperplasia (BPH) are driven by prostate smooth muscle contraction and prostate growth. Smooth muscle contraction in the prostate and other organs critically depends on activation of the small monomeric GTPase RhoA and probably Rac1. A role of another GTPase, ADP-ribosylation factor 6 (ARF6), for smooth muscle contraction has been recently suggested by indirect evidence but remains to be proven for any organ. Here, we report effects of NAV2729, an inhibitor with assumed specificity for ARF6, in human prostate tissues and cultured prostate stromal cells (WPMY-1). NAV2729 (5 μm) inhibited neurogenic and α₁-adrenergic contractions of human prostate tissues. Contractions induced by endothelin-1, by the thromboxane A₂ agonist U46619, or by high molar KCl were not inhibited. Correlation analyses suggested up-regulation of prostatic ARF6 expression with increasing degree of BPH, as ARF6 expression increased with the content of prostate-specific antigen (PSA) of prostate tissues. NAV2729 inhibited ARF6 activity but not other GTPases (ARF1, RhoA, Rac1) in prostate tissues and in WPMY-1 cells. Proliferation of WPMY-1 cells was inhibited concentration-dependently by NAV2726, as reflected by decreased viability, 5-ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, and expression of Ki-67. Silencing of ARF6 expression mimicked effects of NAV2729 on viability and in the EdU assay. Effects of NAV2729 on viability and proliferation were attenuated in cells with silenced ARF6 expression. Our findings suggest that a NAV2729-sensitive mechanism promotes adrenergic contraction and stromal cell growth in the human prostate, which is probably ARF6-mediated. Similar actions in other organs and urodynamic effects of NAV2729 appear possible.

Generation and Regulation of Spontaneous Contractions in the Prostate

Spontaneous myogenic contractions have been shown to be significantly upregulated in prostate tissue collected from men with Benign Prostatic Hyperplasia (BPH), an extremely common disorder of the ageing male. Although originally thought likely to be involved in 'housekeeping' functions, mixing prostatic secretions to prevent stagnation, these spontaneous myogenic contractions provide a novel opportunity to understand and treat BPH. This treatment potential differs from previous models, which focused exclusively on attenuating nerve-mediated neurogenic contractions. Previous studies in the rodent prostate have provided an insight into the mechanisms underlying the regulation of myogenic contractions. 'Prostatic Interstitial Cells' (PICs) within the prostate appear to generate pacemaker potentials, which arise from the summation of number of spontaneous transient depolarisations triggered by the spontaneous release of Ca²⁺ from internal stores and the opening of Ca²⁺-activated Cl^- channels. Pacemaker potentials then conduct into neighbouring smooth muscle cells to generate spontaneous slow waves. These slow waves trigger the firing of 'spike-like' action potentials, Ca²⁺ entry and contraction, which are not attenuated by blockers of neurotransmission. However, these spontaneous prostatic contractions can be modulated by the autonomic nervous system. Here, we discuss the mechanisms underlying rodent and human prostate myogenic contractions and the actions of existing and novel pharmacotherapies for the treatment of BPH. Understanding the generation of human prostatic smooth muscle tone will confirm the mechanism of action of existing drugs, inform the identification and effectiveness of new pharmacotherapies, as well as predict patient outcomes.

Inhibition of Prostate Smooth Muscle Contraction by Inhibitors of Polo-Like Kinases

Background: Prostate smooth muscle contraction plays an important role for pathophysiology and treatment of male lower urinary tract symptoms (LUTS) but is incompletely understood. Because the efficacy of available medication is limited, novel options and improved understanding of prostate smooth muscle contraction are of high demand. Recently, a possible role of polo-like kinase 1 (PLK1) has been suggested for smooth muscle contraction outside the lower urinary tract. Here, we examined effects of PLK inhibitors on contraction of human prostate tissue.

Methods: Prostate tissues were obtained from radical prostatectomy. RT-PCR, Western blot and immunofluorescence were performed to detect PLK expression and phosphorylated PLK. Smooth muscle contractions were induced by electric field stimulation (EFS), α₁-agonists, endothelin-1, or the thromboxane A₂ analog U46619 in organ bath.

Results: RT-PCR, Western blot, and immunofluorescence suggested expression of PLK1 in the human prostate, which may be located and active in smooth muscle cells. EFS-induced contractions of prostate strips were reduced by SBE 13 (1 μM), cyclapolin 9 (3 μM), TAK 960 (100 nM), and Ro 3280 (100 nM). SBE 13 and cyclapolin 9 inhibited contractions by the α₁-agonists methoxamine, phenylephrine, and noradrenaline. In contrast, no effects of SBE 13 or cyclapolin 9 on endothelin-1- or U46619-induced contractions were observed.

Conclusion: Alpha1-adrenergic smooth muscle contraction in the human prostate can be inhibited by PLK inhibitors. PLK-dependent signaling may be a new pathway, which promotes α₁-adrenergic contraction of prostate smooth muscle cells. As contractions by endothelin and U46619 are not susceptible to PLK inhibition, this reflects divergent regulation of adrenergic and non-adrenergic prostate smooth muscle contraction.

Erectile Dysfunction and Lower Urinary Tract Symptoms

CONTEXT

Lower urinary tract symptoms (LUTSs) and erectile dysfunction (ED) are substantial health concerns with a significant impact on the overall male quality of life.

OBJECTIVE

To evaluate the available evidence of the association between LUTSs and ED in patients with benign prostatic hyperplasia (BPH), and discuss possible clinical implications for the management of LUTS/BPH.

EVIDENCE ACQUISITION

A systematic review of the existing literature published between 1997 and June 2017 and available in the Medline, Scopus, and Web of Science databases was conducted using both the Medical Subject Heading (MeSH) and free-text protocols. The MeSH search was conducted by combining the following terms: "lower urinary tract symptoms," "LUTS," "benign prostatic hyperplasia," "BPH," "erectile dysfunction," "sexual dysfunction," "BPE," and "benign prostatic enlargement." The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed.

EVIDENCE SYNTHESIS

Several community-based studies in different geographical areas have provided strong evidence of an age-independent association between LUTSs and ED. Several biological mechanisms have been proposed to explain this association, but further research is required to better understand the molecular pathways involved. It is necessary to evaluate the possible impact of the metabolic syndrome treatment on LUTS/ED management. Considering the possible relationship between LUTSs and ED, their impact on the quality of life, and the possible adverse effects associated with LUTS medical treatment, clinicians should always evaluate ED in patients with LUTSs and take the opportunity to evaluate patients reporting ED for LUTSs.

CONCLUSIONS

Data from the peer-reviewed literature suggest the existence of an association between LUTS/BPH and ED, although their casual relationship has not been established yet. Emerging data also suggest that pathophysiological mechanisms involved in the metabolic syndrome are key factors in both disorders. Considering the association, it is also recommended that men presenting with LUTSs or ED should be evaluated for both disorders. A better understanding of the molecular pathways behind this association may also help identify new possible targets and develop novel therapeutic approaches to manage LUTSs and ED.

PATIENT SUMMARY

In this manuscript, we report on all the available evidence linking erectile dysfunction and lower urinary tract symptoms. Our findings suggest the existence of a strong relationship between these two conditions. On the basis of these findings, we recommend that clinicians always explore both conditions in male patients presenting with either of symptoms.

Inhibition of smooth muscle contraction and ARF6 activity by the inhibitor for cytohesin GEFs, secinH3, in the human prostate

Prostate smooth muscle contraction is critical for etiology and treatment of male lower urinary tract symptoms (LUTS) and is promoted by small monomeric GTPases (RhoA and Rac). GTPases may be activated by guanosine nucleotide exchange factors (GEFs). GEFs of the cytohesin family may indirectly activate Rac, or ADP ribosylation factor (ARF) GTPases directly. Here we investigated the expression of cytohesin family GEFs and effects of the cytohesin inhibitor Sec7 inhibitor H3 (secinH3) on smooth muscle contraction and GTPase activities in human prostate tissues. Of all four cytohesin isoforms, cytohesin-1 and -2 showed the highest expression in real-time PCR. Western blot and fluorescence staining suggested that cytohesin-2 may be the predominant isoform in prostate smooth muscle cells. Contractions induced by norepinephrine, the α₁-adrenoceptor agonist phenylephrine, the thromboxane A₂ analog U-46619 , and endothelin-1 and -3, as well as neurogenic contractions induced by electric field stimulation (EFS), were reduced by secinH3 (30 µM). Inhibition of EFS-induced contractions appeared to have efficacy similar to that of inhibition by the α₁-adrenoceptor antagonist tamsulosin (300 nM). Combined application of secinH3 plus tamsulosin caused larger inhibition of EFS-induced contractions than tamsulosin alone. Pull-down assays demonstrated inhibition of the small monomeric GTPase ARF6 by secinH3, but no inhibition of RhoA or Rac1. In conclusion, we suggest that a cytohesin-ARF6 pathway takes part in smooth muscle contraction. This may open attractive new possibilities in medical treatment of male LUTS.

The Influence of Maxacalcitol, Vitamin D3 Analog, on Detrusor Overactivity in Conscious Rats

OBJECTIVES

To test the hypothesis that maxacalcitol, vitamin D3 analog, would ameliorate detrusor overactivity (DO) induced by retinyl acetate instillation; to test the outcome of the combined administration of maxacalcitol and the rho kinase inhibitor - GSK 269962, amlodipine besylate, or oxybutynin chloride in this model.

METHODS

The rats were treated with maxacalcitol for 14 days. Then, cystometric studies were performed during which the animals were administered test compounds.

RESULTS

Maxacalcitol in a dose of 30 but not 15 µg/kg/day induced reduction in DO index, non-voiding contractions frequency (FNVC), and amplitude (ANVC), while increasing volume threshold to elicit non-voiding contractions (VTNVC). The 14-day-long administration of maxacalcitol at a dose of 15 µg/kg/day to animals, followed by GSK 269962 at a single dose of 10 mg/kg, led to a statistically significant reduction of intercontraction interval and bladder compliance, and an increase in DO index, without any effect on ANVC, FNVC, and VTNVC. The assessment of the combined effect of maxacalcitol (15 µg/kg/day) and amlodipine besylate (0.25 mg/kg) demonstrated an increase in intercontraction interval, bladder compliance and VTNVC, with a decrease in FNVC. No statistically significant changes were found in DO index and ANVC. The combined outcome of administering maxacalcitol (15 µg/kg/day) and oxybutynin chloride (0.25 mg/kg) did not show any statistically significant value of the measured cystometric parameters.

CONCLUSION

The outcomes of maxacalcitol administration can be the result of 3 mechanisms, that is, the upregulation of L-type Ca(2+) channels, the inhibition of the rho kinase pathway, and a so far unknown central mechanism.

Spontaneous Contractile Activity of the Detrusor Muscle and Its Role in the Pathogenesis of Overactive Bladder Syndrome

There is accumulated evidence that spontaneous contractions (SCs) in the bladder wall are associated with afferent nerve firing in the bladder. The role of the urothelium in bladder sensation might be restricted to pathological conditions, such as interstitial cystitis or chemical cystitis in which the release of urothelium-derived mediators such as adenosine triphosphate is increased. Recent publications imply that SCs in bladders with detrusor overactivity due to spinal cord injury or bladder outlet obstruction are modulated by intracellular signal transduction mechanisms such as the RhoA/Rho-kinase pathway, denervation-supersensitivity to acetylcholine, changes in ion channel activity, enhanced gap-junctional intercellular communication, alterations in interstitial cells of Cajal, the actions of local mediators in the detrusor and the influence of the urothelium. Spontaneous contractions and possible consequent afferent nerve firing might participate in the generation of overactive bladder syndrome.

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.

Drug therapy of overactive bladder--what is coming next?

After the approval and introduction of mirabegron, tadalafil, and botulinum toxin A for treatment of lower urinary tract symptoms/overactive bladder, focus of interest has been on their place in therapy versus the previous gold standard, antimuscarinics. However, since these agents also have limitations there has been increasing interest in what is coming next - what is in the pipeline? Despite progress in our knowledge of different factors involved in both peripheral and central modulation of lower urinary tract dysfunction, there are few innovations in the pipe-line. Most developments concern modifications of existing principles (antimuscarinics, β₃-receptor agonists, botulinum toxin A). However, there are several new and old targets/drugs of potential interest for further development, such as the purinergic and cannabinoid systems and the different members of the transient receptor potential channel family. However, even if there seems to be good rationale for further development of these principles, further exploration of their involvement in lower urinary tract function/dysfunction is necessary.

Inhibition of prostate smooth muscle contraction and prostate stromal cell growth by the inhibitors of Rac, NSC23766 and EHT1864

BACKGROUND AND PURPOSE

Medical therapy of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) targets smooth muscle contraction in the prostate, or prostate growth. However, current therapeutic options are insufficient. Here, we investigated the role of Rac in the control of smooth muscle tone in human prostates and growth of prostate stromal cells.

EXPERIMENTAL APPROACH

Experiments were performed using human prostate tissues from radical prostatectomy and cultured stromal cells (WPMY-1). Expression of Rac was examined by Western blot and fluorescence staining. Effects of Rac inhibitors (NSC23766 and EHT1864) on contractility were assessed in the organ bath. The effects of Rac inhibitors were assessed by pull-down, cytotoxicity using a cell counting kit, cytoskeletal organization by phalloidin staining and cell growth using an 5-ethynyl-2'-deoxyuridine assay.

KEY RESULTS

Expression of Rac1-3 was observed in prostate samples from each patient. Immunoreactivity for Rac1-3 was observed in the stroma, where it colocalized with the smooth muscle marker, calponin. NSC23766 and EHT1864 significantly reduced contractions of prostate strips induced by noradrenaline, phenylephrine or electrical field stimulation. NSC23766 and EHT1864 inhibited Rac activity in WPMY-1 cells. Survival of WPMY-1 cells ranged between 64 and 81% after incubation with NSC23766 (50 or 100 μM) or EHT1864 (25 μM) for 24 h. NSC23766 and EHT1864 induced cytoskeletal disorganization in WPMY-1 cells. Both inhibitors impaired the growth of WPMY-1 cells.

CONCLUSIONS AND IMPLICATIONS

Rac may be a link connecting the control of prostate smooth muscle tone with proliferation of smooth muscle cells. Improvements in LUTS suggestive of BPH by Rac inhibitors appears possible.

Pioneering drugs for overactive bladder and detrusor overactivity: Ongoing research and future directions

The ongoing research on pioneering drug candidates for the overactive bladder (OAB) aimed to overcome the limitations of currently licensed pharmacotherapies, such as antimuscarinics, β3-adrenergic agents, and botulinum neurotoxin, has been reviewed performing a systematic literature review and web search. The review covers the exploratory agents alternative to available medications for OAB and that may ultimately prove to be therapeutically useful in the future management of OAB patients based on preclinical and early clinical data. It emerges that many alternative pharmacological strategies have been discovered or are under investigation in disease-oriented studies. Several potential therapeutics are known for years but still find obstacles to pass the clinical stages of development, while other completely novel compounds, targeting new pharmacological targets, have been recently discovered and show potential to translate into clinical therapeutic agents for idiopathic and neurogenic OAB syndrome. The global scenario of investigational drugs for OAB gives promise for the development of innovative therapeutics that may ultimately prove effective as first, combined or second-line treatments within a realistic timescale of ten years.

Increased Rho-kinase-mediated prostate contractions associated with impairment of β-adrenergic-cAMP-signaling pathway by chronic nitric oxide deficiency

Impairment of nitric oxide (NO) - cyclic GMP signaling pathway is likely to contribute to human begnin prostate hyperplasia (BPH). In the present study we have used a model of chronic NO synthesis inhibition to evaluate the functional alterations of prostate smooth muscle (PSM) machinery, and involvement of Rho-kinase pathway. Wistar rats were treated with the NO inhibitor N(ω)-nitro-l-arginine methyl ester (L-NAME, 20mg/kg/day; 4 weeks), after which contractile responses to phenylephrine (α1-adrenoceptor agonist; 1nM to 100µM), carbachol (muscarinic agonist; 1nM to 1mM) and α,β-methylene ATP (P2X receptor agonist; 1-10µM), as well as to electrical-field stimulation (EFS; 1-32Hz) were evaluated. PSM relaxations to isoproterenol (non-selective β-adrenoceptor agonist, 0.1nM to 10µM) and sodium nitroprusside (NO donor, 1nM to 10mM) were also evaluated. The ratio prostate weight/body weight was 22% greater (P<0.05) in L-NAME compared with control group. The PSM contractions to phenylephrine, carbachol and α,β-methylene ATP were higher in L-NAME (Emax: 3.85±0.25, 3.52±0.35 and 2.03±0.2mN, respectively) compared with control group (Emax: 3.08±0.17, 2.37±0.18 and 1.57±0.18mN, respectively). The PSM contractions induced by EFS were also significantly greater in L-NAME group. Prior incubation with the Rho-kinase inhibitor Y27632 (1µM) fully reversed the enhanced contractions to phenylephrine and carbachol. Isoproterenol-induced PSM relaxations were 34% lower in L-NAME group, which was associated with reduced levels of cAMP in prostate tissue. The relaxations to sodium nitroprusside remained unaltered in L-NAME group. In summary, chronic NO deficiency leads to increased Rho-kinase-mediated PSM contractile responses accompanied by impairment of β-adrenergic-cAMP-signaling pathway.

The receptor antagonist picotamide inhibits adrenergic and thromboxane-induced contraction of hyperplastic human prostate smooth muscle

Inhibition of prostate smooth muscle contraction is an important strategy for medical treatment of lower urinary tract symptoms (LUTS). Besides α1-adrenoceptors, prostate smooth muscle contraction is induced by activation of thromboxane (TXA2) receptors (TXA2-R). Here, we examined the effects of the TXA2-R antagonist picotamide on contraction of human prostate tissue. Prostate tissues were obtained from radical prostatectomy. The effects of picotamide (300 μM), L-665,240 (3 μM), and seratrodast (3 μM) on U46619-, electric field stimulation- (EFS-), phenylephrine-, and norepinephrine-induced contractions were studied in organ baths. Expression of TXA2-R and TXA2 synthase (TXS) was examined by fluorescence stainings. Picotamide, seratrodast, and L-655,240 inhibited concentration-dependent contractions induced by the TXA2 analog U46619. Picotamide, but not seratrodast or L-655,240, inhibited frequency-dependent contractions induced by EFS. Picotamide inhibited concentration-dependent contractions induced by norepinephrine or by the selective α1-adrenoceptor agonist phenylephrine. In prostate strips, where only submaximal contraction by a low dose of phenylephrine was induced, application of U46619 raised tone to maximum phenylephrine-induced tension. Immunoreactivity for TXA2-R and TXS was observed in the stroma and in epithelial cells of glands. Colocalization of both immunoreactivites was observed with the smooth muscle markers calponin and α-smooth muscle actin, with the epithelial marker pan-cytokeratin, and with prostate-specific antigen in the stroma and glands. The receptor antagonist picotamide inhibits α1-adrenergic, TXA2-mediated, and EFS-induced contractions in the human prostate. To the best of our knowledge, this is the first antagonist able to inhibit two different contraction systems in the prostate.

New developments in the medical management of overactive bladder

Overactive bladder (OAB) is a clinical syndrome describing the symptom complex of urgency, with or without urgency incontinence and is usually associated with frequency and nocturia. Whilst the majority of women will benefit from initial management with conservative and behavioural intervention a significant number will require medical therapy. Antimuscarinics are currently the most widely prescribed drugs for OAB although very often persistence with medication is limited due to lack of efficacy or intolerable adverse effects. The review, whilst giving a brief overview of OAB syndrome, will focus on new developments in drug therapy for OAB. In addition to evaluating new drugs with different methods of action it will also specifically focus on alternative modalities of treatment and how they may benefit patients with this troublesome and distressing condition.

Age-related changes in the innervation of the prostate gland: implications for prostate cancer initiation and progression

The adult prostate gland grows and develops under hormonal control while its physiological functions are controlled by the autonomic nervous system. The prostate gland receives sympathetic input via the hypogastric nerve and parasympathetic input via the pelvic nerve. In addition, the hypogastric and pelvic nerves also provide sensory inputs to the gland. This review provides a summary of the innervation of the adult prostate gland and describes the changes which occur with age and disease. Growth and development of the prostate gland is age dependent as is the occurrence of both benign prostate disease and prostate cancer. In parallel, the activity and influence of both the sympathetic and parasympathetic nervous system changes with age. The influence of the sympathetic nervous system on benign prostatic hyperplasia is well documented and this review considers the possibility of a link between changes in autonomic innervation and prostate cancer progression.

Future direction in pharmacotherapy for non-neurogenic male lower urinary tract symptoms

BACKGROUND

The pathophysiology of male lower urinary tract symptoms (LUTS) is highly complex and multifactorial. The shift in perception that LUTS are not sex or organ specific has not been followed by significant innovations regarding the available drug classes.

OBJECTIVE

To review pathophysiologic mechanisms and clinical and experimental data related to the development of new pharmacologic treatments for male LUTS.

EVIDENCE ACQUISITION

The PubMed database was used to identify articles describing experimental and clinical studies of pathophysiologic mechanisms contributing to male LUTS and, supported by them, new pharmacotherapies with clinical or experimental evidence in the field.

EVIDENCE SYNTHESIS

Several pathologic processes (eg, androgen signaling, inflammation, and metabolic factors) and targets (eg, the urothelium, prostate, interstitial cells, detrusor, neurotransmitters, neuromodulators, and receptors) have been implicated in male LUTS. Some newly introduced drugs, such as phosphodiesterase type 5 inhibitors and β3-adrenergic agonists, have just started broad use in clinical practice. Drugs with potential benefit, such as vitamin D3 receptor analogs, gonadotropin-releasing hormone antagonists, cannabinoids, and drugs injected into the prostate, have been evaluated in experimental studies and have progressed to clinical trials. However, safety and efficacy data for these drugs are still scarce. Some compounds with interesting profiles have only been tested in experimental settings (eg, transient receptor potential channel blockers, Rho-kinase inhibitors, purinergic receptor blockers, and endothelin-converting enzyme inhibitors).

CONCLUSIONS

New pathophysiologic mechanisms of male LUTS are described that lead to the continuous development of new pharmacotherapies. To date, few drugs have been added to the current armamentarium, and several are in various phases of clinical or experimental investigation.

Noradrenaline induces binding of Clathrin light chain A to α1-adrenoceptors in the human prostate

BACKGROUND

Binding of clathrins or caveolin to G protein-coupled receptors may induce post-translational modifications of receptor function. Receptor regulation by clathrin requires cofactors ADP-ribosylation factor 6 (ARF6) and adaptin, while dynamin is required for clathrin- and caveolin-dependent mechanisms.

OBJECTIVE

To investigate the expression and α1-adrenoceptor binding of clathrins, caveolin, and their cofactors in the human prostate.

METHODS

Prostate tissue was obtained from radical prostatectomy. Expression of clathrin heavy chain (HC), clathrin light chain A and B (LCA, LCB), caveolin-1, ARF6, β-adaptin, and dynamin-2 was studied by RT-PCR, Western blot, immunohistochemistry, and fluorescence staining. Interaction of α1A-adrenoceptors with clathrins and caveolin-1 was studied by coimmunoprecipitation.

RESULTS

mRNA and protein expression of clathrin HC, LCA, LCB, caveolin-1, dynamin-2, and β-adaptin was detected in prostate tissues of each patient. Immunohistochemistry demonstrated the expression of clathrin HC, LCA, LCB, caveolin, dynamin, and β-adaptin in stromal cells. Immunoreactivity for these proteins colocalized with α-smooth muscle actin and α1A-adrenoceptors in double fluorescence staining. Coimmunoprecipitation demonstrated that α1A-adrenoceptors in prostate tissue interact with clathrin HC and LCB under resting conditions, but not with caveolin-1. Stimulation of prostate tissues with noradrenaline (30 µM) in vitro induced binding of clathrin LCA to α1A-adrenoceptors.

CONCLUSIONS

The prostatic α1-adrenoceptor population is at least partially bound to clathrin HC and LCB. Upon receptor activation, prostate α1A-adrenoceptors bind clathrin LCA. This points to a new concept of post-translational α1-adrenoceptor regulation in the prostate, which includes receptor interaction with accessory binding partners.

Effects of the Rho kinase inhibitor, hydroxyfasudil, on bladder dysfunction and inflammation in rats with HCl-induced cystitis

OBJECTIVE

To evaluate the effect of the Rho kinase inhibitor, hydroxyfasudil, on bladder function in a rat model of HCl-induced chemical cystitis, and to elucidate the possible mechanisms associated with its therapeutic effect.

METHODS

Female Sprague-Dawley rats with HCl-induced cystitis were given hydroxyfasudil (10 mg/kg, i.p.) for 7 days. Treatment efficacy was determined by comparing bladder function and histopathology to sham and untreated control rats. Bladder function was determined by cystometric analysis. Rho kinase activity was determined by quantitative reverse transcription polymerase chain reaction and signal inhibition of downstream Ras homolog member A/Rho kinase signaling molecules by western blot and immunohistochemistry.

RESULTS

Treatment with hydroxyfasudil significantly improved bladder intercontraction intervals. Rats treated with hydroxyfasudil also showed a significant reduction of histopathological features associated with cystitis. Western blot and immunohistochemistry findings showed that hydroxyfasudil inhibited downstream molecules of Rho kinase that ameliorated changes associated with HCl-induced chemical cystitis, such as inflammatory cell recruitment and smooth muscle cell proliferation.

CONCLUSION

The findings from the present study suggest a promising therapeutic role for hydroxyfasudil in bladder inflammation associated with cystitis.

Inhibition of adrenergic human prostate smooth muscle contraction by the inhibitors of c-Jun N-terminal kinase, SP600125 and BI-78D3

BACKGROUND AND PURPOSE α(1) -Adrenoceptor-induced contraction of prostate smooth muscle is mediated by calcium- and Rho kinase-dependent mechanisms. In addition, other mechanisms, such as activation of c-jun N-terminal kinase (JNK) may be involved. Here, we investigated whether JNK participates in α(1)-adrenoceptor-induced contraction of human prostate smooth muscle. EXPERIMENTAL APPROACH Prostate tissue was obtained from patients undergoing radical prostatectomy. Effects of the JNK inhibitors SP600125 (50 µM) and BI-78D3 (30 µM) on contractions induced by phenylephrine, noradrenaline and electric field stimulation (EFS) were studied in myographic measurements. JNK activation by noradrenaline (30 µM) and phenylephrine (10 µM), and the effects of JNK inhibitors of c-Jun phosphorylation were assessed by Western blot analyses with phospho-specific antibodies. Expression of JNK was studied by immunohistochemistry and fluorescence double staining. KEY RESULTS The JNK inhibitors SP600125 and BI-78D3 reduced phenylephrine- and noradrenaline-induced contractions of human prostate strips. In addition, SP600125 reduced EFS-induced contraction of prostate strips. Stimulation of prostate tissue with noradrenaline or phenylephrine in vitro resulted in activation of JNK. Incubation of prostate tissue with SP600125 or BI-78D3 reduced the phosphorylation state of c-Jun. Immunohistochemical staining demonstrated the expression of JNK in smooth muscle cells of human prostate tissue. Fluorescence staining showed that α(1A)-adrenoceptors and JNK are expressed in the same cells. CONCLUSIONS AND IMPLICATIONS Activation of JNK is involved in α(1)-adrenoceptor-induced prostate smooth muscle contraction. Models of α(1)-adrenoceptor-mediated prostate smooth muscle contraction should include this JNK-dependent mechanism.

The effect of hypercholesterolemia on carbachol-induced contractions of the detrusor smooth muscle in rats: increased role of L-type Ca2+ channels

To investigate a possible relation between hypercholesterolemia and detrusor smooth muscle function, we studied the contractile response to potassium challenge, carbachol (CCh), and the components of CCh-induced contractile mechanism in high-cholesterol diet-fed rats. Adult male Sprague-Dawley rats were fed with standard (control group, N = 17) or 4 % cholesterol diet (hypercholesterolemia group (HC), N = 16) for 4 weeks. Spontaneous contractions of detrusor muscle strips and their responses to potassium chloride (KCl) or cumulative dose-contraction curves to CCh were recorded. The effects of muscarinic receptor antagonists (methoctramin and/or 4-diphenylacetoxy-N-methylpiperidine), L-type Ca(+2) channel blocker (nifedipine), and/or rho-kinase inhibitor Y-27632 were investigated. Blood cholesterol level was increased in the HC group with no sign of atherosclerosis. The KCl-induced detrusor smooth muscle contractions were higher in HC, whereas spontaneous and CCh-induced responses were similar in both groups. Preincubation with receptor antagonist for M(3) but not for M(2) attenuated contraction significantly, shifting the dose-response curve to the right. This response was similar in both groups. Among two effector mechanisms of M(3)-mediated detrusor smooth muscle contraction, rho-kinase pathway was not affected by hypercholesterolemia, whereas blockade of L-type Ca(+2) channels potently reduced contractions. The results of this study point out a relation between hypercholesterolemia and contractile mechanism of detrusor smooth muscle likely to change urinary bladder function, via altering L-type Ca(+2) channels. Taken together with escalating incidence of hypercholesterolemia and lower urinary tract symptoms, it is a field which deserves to be investigated further.

Phase IIb, multicenter, double-blind, randomized, placebo-controlled, parallel-group study to determine effects of elocalcitol in women with overactive bladder and idiopathic detrusor overactivity

OBJECTIVE

To evaluate the efficacy and safety of elocalcitol in the treatment of women with overactive bladder and idiopathic detrusor overactivity.

METHODS

The study was a multicenter, double-blind, randomized, placebo-controlled, parallel-group trial of women with overactive bladder symptoms recruited from 48 European tertiary referral centers. The participants were randomized to receive either placebo or elocalcitol, 75 μg/d or 150 μg/d for 4 weeks. A 3-day bladder diary, the Urgency Perception Scale, the Patient's Perception of Bladder Condition, and urodynamics were used before and after treatment. Vital signs, laboratory blood tests, 24-hour urine collection, and electrocardiography were also performed to assess the safety. The analysis of covariance test was used to compare the treatment groups. The primary objective was to evaluate the change in bladder volume at the first involuntary detrusor contraction from baseline.

RESULTS

A total of 308 women were studied. No significant change was seen in the urodynamic parameters between the placebo and elocalcitol groups, except for the bladder volume at the first desire to void. The frequency of incontinence episodes was significantly reduced in the elocalcitol group compared with the placebo group (P = .02). The Patient's Perception of Bladder Condition score improved significantly after treatment for the women receiving elocalcitol compared with those receiving placebo (P = .02). Treatment with both doses of elocalcitol was well tolerated, and no differences versus placebo were observed.

CONCLUSION

Although the primary endpoint was not achieved, elocalcitol appears to be an effective and well-tolerated drug for the treatment of women with overactive bladder and idiopathic detrusor overactivity. However, the multicenter setting for the use of urodynamics might have biased the results of our study.

Impact of partial urethral obstruction on bladder function: time-dependent changes and functional correlates of altered expression of Ca²⁺ signaling regulators

In animal models of partial urethral obstruction (PUO), altered smooth muscle function/contractility may be linked to changes in molecules that regulate calcium signaling/sensitization. PUO was created in male rats, and urodynamic studies were conducted 2 and 6 wk post-PUO. Cystometric recordings were analyzed for the presence or absence of nonvoiding contractions [i.e., detrusor overactivity (DO)]. RT-PCR and Western blots were performed on a subpopulation of rats to study the relationship between the expression of RhoA, L-type Ca(2+) channels, Rho kinase-1, Rho kinase-2, inositol 1,4,5-trisphosphate, ryanodine receptor, sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 and protein kinase C (PKC)-potentiated phosphatase inhibitor of 17 kDa, and urodynamic findings in the same animal. Animals displayed DO at 2 (38%) and 6 wk (43%) post-PUO, increases were seen in in vivo pressures at 2 wk, and residual volume at 6 wk. Statistical analysis of RT-PCR and Western blot data at 2 wk, during the compensatory phase of detrusor hypertrophy, documented that expression of molecules that regulate calcium signaling and sensitization was consistently lower in obstructed rats without DO than those with DO or control rats. Among rats with DO at 2 wk, linear regression analysis revealed positive correlations between in vivo pressures and protein and mRNA expression of several regulatory molecules. At 6 wk, in the presence of overt signs of bladder decompensation, no clear or consistent alterations in expression of these same targets were observed at the protein level. These data extend prior work to suggest that molecular profiling of key regulatory molecules during the progression of PUO-mediated bladder dysfunction may shed new light on potential biomarkers and/or therapeutic targets.