Differential expression of estrogen receptors alpha and beta in adult rat accessory sex glands and lower urinary tract

Estrogen inhibits bladder overactivity in rats with cyclophosphamide-induced cystitis via downregulating the expression of P2X3 receptors in bladder epithelium cells

AIMS

The therapeutic effect of estrogen on interstitial cystitis/bladder pain syndrome is unclear. We aim to explore the effect of estrogen on bladder overactivity in rats with cyclophosphamide-induced cystitis and its underlying mechanism.

METHODS

In vivo cystometry was used to determine the effect of estrogen on bladder excitability. The effect of estrogen on the expression of P2X3 receptors in bladder epithelium was detected by real-time polymerase chain reaction and western blot. Effect of P2X3 receptors in bladder urothelium on stretch-released adenosine triphosphate was performed by a Flexcell FX5000 Compression system and an Enzyme-Linked Immunosorbent Assay Kit.

RESULTS

Estrogen deprivation significantly increased the urinary frequency, while supplementation with diarylpropionitrile (DPN), an estrogen receptor β (ERβ) agonist, alleviated the urinary frequency. 17β-Estradiol and DPN decreased the expression of P2X3 receptors in urothelium cells which was partially inhibited by ERβ antagonist 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-3-yl]phenol. Meanwhile, inhibiting the expression of P2X3 receptors by ERβ agonist or antagonizing the function of P2X3 receptors by selective P2X3 receptor antagonist AF-353 or A-317491 significantly reduced the stretch-released ATP from urothelium cells.

CONCLUSIONS

Estrogen has a direct effect on the regulation of bladder overactivity in rats with cyclophosphamide-induced cystitis by downregulating the expression of bladder epithelial P2X3 receptors through ERβ and reducing the adenosine triphosphate released from urothelium during bladder filling, thereby inhibiting the generation of the micturition reflex.

Estrogen receptors in human bladder cells regulate innate cytokine responses to differentially modulate uropathogenic E. coli colonization

The bladder epithelial cells elicit robust innate immune responses against urinary tract infections (UTIs) for preventing the bacterial colonization. Physiological fluctuations in circulating estrogen levels in women increase the susceptibility to UTI pathogenesis, often resulting in adverse health outcomes. Dr adhesin bearing Escherichia coli (Dr E. coli) cause recurrent UTIs in menopausal women and acute pyelonephritis in pregnant women. Dr E. coli bind to epithelial cells via host innate immune receptor CD55, under hormonal influence. The role of estrogens or estrogen receptors (ERs) in regulating the innate immune responses in the bladder are poorly understood. In the current study, we investigated the role of ERα, ERβ and GPR30 in modulating the innate immune responses against Dr E. coli induced UTI using human bladder epithelial carcinoma 5637 cells (HBEC). Both ERα and ERβ agonist treatment in bladder cells induced a protection against Dr E. coli invasion via upregulation of TNFα and downregulation of CD55 and IL10, and these effects were reversed by action of ERα and ERβ antagoinsts. In contrast, the agonist-mediated activation of GPR30 led to an increased bacterial colonization due to suppression of innate immune factors in the bladder cells, and these effects were reversed by the antagonist-mediated suppression of GPR30. Further, siRNA-mediated ERα knockdown in the bladder cells reversed the protection against bacterial invasion observed in the ERα positive bladder cells, by modulating the gene expression of TNFα, CD55 and IL10, thus confirming the protective role of ERα. We demonstrate for the first time a protective role of nuclear ERs, ERα and ERβ but not of membrane ER, GPR30 against Dr E. coli invasion in HBEC 5637 cells. These findings have many clinical implications and suggest that ERs may serve as potential drug targets towards developing novel therapeutics for regulating local innate immunity and treating UTIs.

Sex differences in lower urinary tract biology and physiology

Females and males differ significantly in gross anatomy and physiology of the lower urinary tract, and these differences are commonly discussed in the medical and scientific literature. However, less attention is dedicated to investigating the varied development, function, and biology between females and males on a cellular level. Recognizing that cell biology is not uniform, especially in the lower urinary tract of females and males, is crucial for providing context and relevance for diverse fields of biomedical investigation. This review serves to characterize the current understanding of biological sex differences between female and male lower urinary tracts, while identifying areas for future research. First, the differences in overall cell populations are discussed in the detrusor smooth muscle, urothelium, and trigone. Second, the urethra is discussed, including anatomic discussions of the female and male urethra followed by discussions of cellular differences in the urothelial and muscular layers. The pelvic floor is then reviewed, followed by an examination of the sex differences in hormonal regulation, the urinary tract microbiome, and the reticuloendothelial system. Understanding the complex and dynamic development, anatomy, and physiology of the lower urinary tract should be contextualized by the sex differences described in this review.

Recruited mast cells in the tumor microenvironment enhance bladder cancer metastasis via modulation of ERβ/CCL2/CCR2 EMT/MMP9 signals

Early clinical studies suggested that infiltrating mast cells could be associated with a poor outcome in bladder cancer (BCa) patients. The mechanisms of how mast cells influence the BCa progression, however, are unclear. Using the human clinical BCa sample survey and in vitro co-culture systems, we found BCa cells could recruit more mast cells than the surrounding non-malignant urothelial cells. The consequences of this better recruitment of mast cells toward BCa cells could then enhance BCa cell invasion. Mechanism dissection revealed that the enhanced BCa cell invasion could function via up-regulation of the estrogen receptor beta (ERβ) in both mast cells and BCa cells, which resulted in the increased CCL2/CCR2/EMT/MMP9 signals. Using the pre-clinical mouse BCa model, we further validated the mast cell-promoted BCa invasion. Interruption of the newly identified ERβ/CCL2/CCR2/EMT/MMP9 pathway via either ERβ-siRNA, ERβ antagonist PHTPP, or CCR2 antagonist can effectively reverse the mast cell-enhanced BCa cells invasion. Together, our finding could lead to the development of an alternative new therapeutic approach to better treat BCa metastasis.

Discovery of a Novel Seminal Fluid Microbiome and Influence of Estrogen Receptor Alpha Genetic Status

Bacteria harbored in the male reproductive system may influence reproductive function and health of the male and result in developmental origins of adult health and disease (DOHaD) effects in his offspring. Such effects could be due to the seminal fluid, which is slightly basic and enriched with carbohydrates; thereby, creating an ideal habitat for microbes or a potential seminal fluid microbiome (SFM). Using wild-type (WT) and estrogen receptor-alpha (ESR1) knockout (KO) male mice, we describe a unique SFM whose inhabitants differ from gut microbes. The bacterial composition of the SFM is influenced according to whether mice have functional Esr1 genes. Propionibacterium acnes, causative agent of chronic prostatitis possibly culminating in prostate cancer, is reduced in SFM of ESR1 KO compared to WT mice (P ≤ 0.0007). In certain genetic backgrounds, WT mice show a greater incidence of prostate cancer than ESR1 KO, which may be due to increased abundance of P. acnes. Additionally, select gut microbiome residents in ESR1 KO males, such as Lachnospiraceae and Christensenellaceae, might contribute to previously identified phenotypes, especially obesity, in these mutant mice. Understanding how genetics and environmental factors influence the SFM may provide the next frontier in male reproductive disorders and possibly paternal-based DOHaD diseases.

[TECAR therapy for Peyronie’s disease: a phase-one prospective study. Great evidence in patients with erectile dysfunction]

Our phase-one prospective study wants to evaluate the safety and tolerability of TECAR therapy in the treatment of Peyronie’s disease. From June 2011 to September 2012 we enrolled 70 patients. Each patient had been previously subjected to andrological examination, to a questionnaire for the evaluation of IPP and ED, and the SF-36 (V1) for the evaluation of the general state of health. The evaluation of pain was made using the VAS scale of pain. Every patient was subjected to TECAR treatment of the fibrotic plaque (both in resistive mode and in capacitive mode) for a total of three sessions carried out on consecutive days. We recorded a good compliance by patients; none of them reported side effects. Pain was decreased by the technique in 80% of the cases.The whole sample completed the study. Surprisingly enough those patients who complained also of erectile dysfunction, reported an improvement in sexual potency.

Estrogenic action on innate defense mechanisms in the urinary tract

Clinical data suggest an impact of estrogen on the pathogenesis of urinary tract infections (UTI). In particular, women after menopause often suffer from recurrent UTI, characterized by at least three acute UTI episodes within a year. Aside from bacterial factors promoting persistence within the urinary bladder, the low estrogen levels induce structural and chemical changes in the urogenital tract which facilitate UTI. Increased residual urine volume and changes in the vaginal microflora are well documented risk factors. Local supplementation with estrogen can at least partly reverse these changes. Treatment allows the re-establishment of a lactobacilli-dominated vaginal microflora and improves epithelial differentiation and integrity in the urogenital tract. This estrogenic effect on the epithelium is marked by an increased production of antimicrobial peptides and a tighter intercellular connection, preventing bacteria from reaching cells where they can hide and later emerge and cause a new infection. Estrogen in the dosages and applications used to date is considered safe for the endometrium in the majority of women. Based on the actions and safety of estrogen, local supplementation thus offers a treatment option for postmenopausal women suffering from recurrent UTI.

Dietary phytoestrogen improves relaxant responses to 17-β-estradiol in aged but not ovariectomised rat bladders

This study examined the effect of age, ovariectomy and dietary phytoestrogen ingestion on 17-β-estradiol-mediated relaxant responses and messenger RNA (mRNA) and protein expression of oestrogen receptor subtypes in the rat isolated bladder. Female Wistar rats (8 weeks) were anaesthetised, and the ovaries were removed (ovx) or left intact (sham). Rats were fed either normal rat chow (soy, phytoestrogens) or a non-soy (phytoestrogen free) diet. Isolated bladder from rats aged 12, 24 or 52 weeks were pre-contracted with 3 μM carbachol prior to obtaining a concentration response curve to 17-β-estradiol. Protein and mRNA expression of the oestrogen receptor subtypes was completed using immunohistochemistry and real-time PCR, respectively. Relatively moderate relaxant responses to 17-β-estradiol were observed in bladders from all age and treatment groups. However, in soy-fed sham 52-week-old rats, the bladder exhibited enhanced relaxant responses to 17-β-estradiol when compared to tissues from other age-matched rat treatment groups (P < 0.05). In bladders from female rats, the mRNA and protein expression of oestrogen receptors β was significantly greater than the expression of the oestrogen receptor α. Oestrogen receptor α mRNA expression declined with age (P < 0.05), whereas oestrogen receptor β expression did not change in any of the treatment groups (P > 0.05). Diet, overiectomy or age did not alter the protein expression of either oestrogen receptor subtype in the bladder (P > 0.05). While a soy diet improved relaxant effects to the 17-β-estradiol with age, it did not alter relaxant responses in bladders from ovariectomised rats.

Chemoprevention of BBN-Induced Bladder Carcinogenesis by the Selective Estrogen Receptor Modulator Tamoxifen

Bladder cancer is the fifth most frequent tumor in men and ninth in women in the United States. Due to a high likelihood of recurrence, effective chemoprevention is a significant unmet need. Estrogen receptors (ERs), primarily ERβ, are expressed in normal urothelium and urothelial carcinoma, and blocking ER function with selective ER modulators such as tamoxifen inhibits bladder cancer cell proliferation in vitro. Herein, the chemoprotective potential of tamoxifen was evaluated in female mice exposed to the bladder-specific carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Carcinogen treatment resulted in a 76% tumor incidence and increased mean bladder weights in comparison to controls. In contrast, mice receiving tamoxifen concurrent (8-20 weeks) or concurrent and subsequent (8-32 weeks) to BBN administration had no change in bladder weight and only 10% to 14% incidence of tumors. Non-muscle-invasive disease was present in animals treated with tamoxifen before (5-8 weeks) or after (20-32 weeks) BBN exposure, while incidence of muscle-invasive bladder carcinoma was reduced. ERβ was present in all mice and thus is a potential mediator of the tamoxifen chemoprotective effect. Surprisingly, ERα expression, which was detected in 74% of the mice exposed to BBN alone but not in any controlmice, was correlated with tumor incidence, indicating a possible role for this receptor in carcinogen-induced urothelial tumorigenesis. Thus, these data argue that both ERα and ERβ play a role in modulating carcinogen-induced bladder tumorigenesis. Administration of tamoxifen should be tested as a chemopreventive strategy for patients at high risk for bladder cancer recurrence.

[Role of estrogens in lower urinary tract physiology and physiopathology]

GOAL

The aim was to review the literature on estrogens and lower urinary tract.

MATERIAL

A review of literature through the PubMed library until December 31, 2012 was carried out using the following keywords: lower urinary tract, bladder, urethra, nervous central system, innervation, female, women, estrogen, estradiol, urogenital atrophy, urinary incontinence, overactive bladder, urinary tract infection.

RESULTS

On the bladder, estrogens are involved in the trophicity, vascularisation, alpha-adrenergic, cholinergic and muscarinic receptor density, detrusor contractility and inflammation. On the urethra, they impact vascularisation, contractility, urethral pulse and tone, anatomical and functional length. On the neurological control, they act on capsaicin-sensitive afferent fibres, neurological regeneration, nerve growth factor expression and viscerovisceral sensitisation.

CONCLUSION

Estrogens play a major role on the lower urinary tract physiology and physiopathology both on the urethra and the bladder.

The expression and actions of androgen receptor in upper urinary tract urothelial carcinoma (UUTUC) tissues and the primary cultured cells

Sex hormone receptors, androgen receptor (AR) and estrogen receptors (ERs) including both ERα and ERβ, mediate the actions of sex hormones. In this study, we aimed to evaluate sex hormone receptors expression in upper urinary tract urothelial carcinomas (UUTUCs) of ureter and renal pelvis with different tumor stages and grades as well as their possible roles in tumor progression. Immunohistochemistry was used to assay the expression of AR and ERs in the primary UUTUCs. XTT viability test was applied to evaluate cell responses for anticancer drug treatment. Wound healing assay was performed to determine cell migration abilities. AR and ERβ immunoreactivities were observed in both UUTUCs, but ERα was not detected in either UUTUCs. In UUTUC of ureter specimens, higher AR expression was found in superficial or lower grade tumors. In contrast, little difference of ERβ expression was found in superficial versus muscle-invasive tumor stages or low grades versus high grades in UUTUCs of ureter specimens. Furthermore in the primary cultured cells from UUTUC specimens, the addition of functional AR reduced cell chemosensitivity, but increased cell migration. These results provide the first data showing the expression patterns of sex hormone receptors in both renal pelvis and ureter UUTUCs. From results, we concluded that there is a positive correlation for higher AR expression found in superficial or low-grade UUTUCs of ureter and identified the functional roles of AR in UUTUC progression.

Understanding the gender disparity in bladder cancer risk: the impact of sex hormones and liver on bladder susceptibility to carcinogens

It has long been known that bladder cancer (BC) incidence is approximately four-fold higher in men than in women in the United States, and a similar disparity also exists in other countries. The reason for this phenomenon is not known, which impedes progress in BC prevention. However, BC incidence is also significantly higher in male animals than in their female counterparts after treatment with aromatic amines, which are principal human bladder carcinogens. These animal studies and related studies in the context of available human data provide significant insight into what may drive the excessive BC risk in men, which is the focus of this article. The carcinogenicity and biotransformation of bladder carcinogens as well as the impact of sex hormones on these processes are discussed, highlighting the novel concept that the gender disparity in BC risk may result primarily from the interplay of androgen, estrogen, and liver, with the liver functioning via its metabolic enzymes as the main decider of bladder exposure to carcinogens in the urine and the male and female hormones exerting opposing effects on carcinogenesis in the bladder and likely also on liver enzymes handling bladder carcinogens. The findings may facilitate further investigation into the mechanism of gender disparity in BC risk and may also have important implications for BC prevention.

A single dose of enterolactone activates estrogen signaling and regulates expression of circadian clock genes in mice

Enterolactone (EL) is an enterolignan produced by gut microbiota from dietary plant lignans. Epidemiological and experimental studies suggest that EL and plant lignans may reduce the risk of breast and prostate cancer as well as cardiovascular disease. These effects are thought to at least in part involve modulation of estrogen receptor activity. Surprisingly little is known about the in vivo estrogenicity of EL. In the present study, we investigated the target tissues of EL, the genes affected by EL treatment, and the response kinetics. Following a single dose of EL, luciferase was significantly induced in reproductive and nonreproductive tissues of male and female 3xERE-luciferase mice, indicating estrogen-like activity. Microarray analysis revealed that EL regulated the expression of only 1% of 17β-estradiol target genes in the uterus. The majority of these genes were traditional estrogen target genes, but also members of the circadian signaling pathway were affected. Kinetic analyses showed that EL undergoes rapid phase II metabolism and is efficiently excreted. In vivo imaging demonstrated that the estrogen response followed similar, fast kinetics. We conclude that EL activates estrogen signaling in both male and female mice and that the transient responses may be due to the fast metabolism of the compound. Lastly, EL may represent a link among diet, gut microbiota, and circadian signaling.

Impact of gender on bladder cancer incidence, staging, and prognosis

INTRODUCTION

While patient gender is an important factor in the clinical decision-making for the management of bladder cancer, there are minimal evidence-based recommendations to guide health care professionals. Recent epidemiologic and translational research has shed some light on the complex relationship between gender and bladder cancer. Our aim was to review the literature on the effect of gender on bladder cancer incidence, biology, mortality, and treatment.

METHODS

Using MEDLINE, we performed a search of the literature between January 1975 and April 2011.

RESULTS

Although men are nearly 3-4 times more likely to develop bladder cancer than women, women present with more advanced disease and have worse survival. Recently, a number of population-based and multicenter collaborative studies have shown that female gender is associated with a significantly higher rate of cancer-specific recurrence and mortality after radical cystectomy. The disparity between genders is proposed to be the result of a differences exposure to carcinogens (i.e., tobacco and chemicals) as well as reflective of genetic, anatomic, hormonal, societal, and environmental factors. Explanations for the differential behavior of bladder cancer between genders include sex steroids and their receptors as well as inferior quality of care for women (inpatient length of stay, referral patterns, and surgical outcomes).

CONCLUSIONS

It is imperative that health care practitioners and researchers from disparate disciplines collectively focus efforts to appropriately develop gender-specific evidence-based guidelines for bladder cancer patients. We must strive to develop multidisciplinary collaborative efforts to provide tailored gender-specific care for bladder cancer patients.

The effect of age and gender on bladder cancer: a critical review of the literature

While patient age and gender are important factors in the clinical decision-making for treating urothelial carcinoma of the bladder (UCB), there are no evidence-based recommendations to guide healthcare professionals. We review previous reports on the influence of age and gender on the incidence, biology, mortality and treatment of UCB. Using MEDLINE, we searched for previous reports published between January 1966 and July 2009. While men are three to four times more likely to develop UCB than women, women present with more advanced disease and have worse survival rates. The disparity among genders is proposed to be the result of a differential exposure to carcinogens (i.e. tobacco and chemicals) as well as reflecting genetic, anatomical, hormonal, societal and environmental factors. Inpatient length of stay, referral patterns for haematuria and surgical outcomes suggest that inferior quality of care for women might be an additional cause of gender inequalities. Age is the greatest single risk factor for developing UCB and dying from it once diagnosed. Elderly patients face both clinical and institutional barriers to appropriate treatment; they receive less aggressive treatment and sub-therapeutic dosing. Much evidence suggests that chronological age alone is an inadequate indicator in determining the clinical and behavioural response of older patients to UCB and its treatment. Epidemiological and mechanistic molecular studies should be encouraged to design, analyse and report gender- and age-specific associations. Improved bladder cancer awareness in the lay and medical communities, careful patient selection, treatment tailored to the needs and the physiological and physical reserve of the individual patient, and proactive postoperative care are particularly important. We must strive to develop transdisciplinary collaborative efforts to provide tailored gender- and age-specific care for patients with UCB.

Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility

BACKGROUND

The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood.

OBJECTIVE

We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility.

METHODS

Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays.

RESULTS

The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the "neuroactive ligand-receptor interactions" family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production.

CONCLUSIONS

Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose-albeit not environmental-of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

Dietary soy isoflavone replacement improves detrusor overactivity of ovariectomized rats with altered connexin-43 expression in the urinary bladder

To evaluate the effects of dietary soy isoflavone on detrusor overactivity (DO) in ovariectomized (Ovx) rats and the association between these effects and expression of the gap junction protein, connexin-43, in the urinary bladder, and to discuss the usefulness of soy isoflavones for overactive bladder (OAB).

MATERIALS AND METHODS

In all, 24 (8-week-old) virgin female Sprague-Dawley rats were divided equally into four groups: sham operation with control diet (with no dietary soy isoflavones; Sham-CD), bilateral Ovx with CD (Ovx-CD), sham operation with soy isoflavone diet (Sham-ID), bilateral Ovx with soy ID (Ovx-ID). Cystometry was performed after the 4-week CD or ID in each group while awake. Quantitative reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemical and Western blot analyses were also performed to examine the expression of connexin-43 in each group.

RESULTS

In Ovx-CD rats, there were some significant changes in cystometry variables, including shortening of the intercontraction interval and an increased number of non-voiding contractions compared with Sham-CD rats (P < 0.05). These changes were significantly improved by 4-week soy isoflavone administration (Ovx-ID; P < 0.05). Quantitative RT-PCR, immunohistochemical and Western blot analyses showed that the expression level of connexin-43 mRNA and protein was significantly greater in the urinary bladder of Ovx-CD rats compared with Sham-CD rats. Soy isoflavone administration significantly reduced this increased expression (Ovx-ID).

CONCLUSIONS

Soy isoflavone replacement improved DO with alteration of the connexin-43 expression pattern in the urinary bladder of Ovx rats. Routine consumption of diet soy isoflavones may be a useful treatment to prevent and improve OAB.

Vascular endothelial growth factor expression in the urethral epithelium of castrated adult female rats treated with tamoxifen

OBJECTIVE

The aim of this study was to evaluate the effects of tamoxifen on vascular endothelial growth factor (VEGF) expression in the urethral epithelium of castrated rats.

MATERIALS AND METHODS

Thirty-six adult, castrated, female Wistar-Hannover rats were randomly divided into two groups: group I (n = 16, control), receiving only propylene glycol, and group II (n = 20, tamoxifen), treated with 250 microg/day of tamoxifen for 30 consecutive days by gavage. On the 31st day, the animals were sacrificed and the urethras were immediately removed, separated into the proximal and distal segments and processed for VEGF immunohistochemistry. The data were analysed using Student's t-test (p < 0.05).

RESULTS

The mean percentage of VEGF expression in the epithelium of the proximal urethra of the animals in groups I and II was 64.47+/-3.70 and 74.69+/-3.03, respectively (p < 0.03), whereas the mean percentage of VEGF expression in the distal urethral epithelium of the animals in groups I and II was 53.49+/-4.64 and 68.57+/-3.67, respectively (p < 0.01).

CONCLUSIONS

Our results indicate that, at the dose and during the time of treatment used, tamoxifen increased VEGF expression in the urethral epithelium of castrated rats.

Effects of raloxifene on the urethra of adult castrated female rats

OBJECTIVE

The objective of this study was to evaluate the effects of raloxifene on the weight and epithelial thickness of the urethra of castrated female rats.

METHODS

Forty castrated female rats were randomly separated into two groups: group I (control, n = 20) received only the vehicle, and group II (raloxifene, n = 20) received 750 microg/day of raloxifene for 30 days. On the 31st day, the animals were sacrificed and the urethras were removed for the study. A model for categorical data using the weighted minimum mean square error method and Student's t test were used for the data analysis (p < 0.05).

RESULTS

The mean weights of the urethras in groups I and II were 22 +/- 1.6 mg and 24 +/- 1.7 mg, respectively (p = 0.371). There was an increase in the mean epithelial thickness of the distal segments in group II compared to group I (50.7 +/- 1.9 microm vs. 45.3 +/- 1.6 microm, respectively) (p < 0.04). No statistically significant difference was found in the mean epithelial thickness of the proximal urethra between the two groups (p = 0.187).

CONCLUSION

Raloxifene administered to castrated female rats for 30 days increased the distal urethral epithelial thickness and did not alter the weight of the urethra.

Investigating the associations between nocturia and sleep disorders in perimenopausal women

PURPOSE

We determined the associations between nocturia and sleep disorders in perimenopausal women.

MATERIALS AND METHODS

A total of 100 women with nocturia were compared to 200 without nocturia. Obstructive sleep apnea, insomnia, anxiety and menopausal stage were assessed using validated questionnaires. Comorbidities associated with nocturia were determined by bivariate analysis and multivariate logistic regression.

RESULTS

Independent associations for nocturia were anxiety (OR 2.11, 95% CI 1.08-4.13), black American race (OR 2.00, 95% CI 1.06-3.85), obstructive sleep apnea symptoms (OR 1.73, 95% CI 1.18-2.53) and insomnia (OR 1.11, 95% CI 1.05-1.12).

CONCLUSIONS

Nocturia is associated with sleep disorders in perimenopausal women.

Morphometric analysis of the urethra of castrated female rats treated with tamoxifen

OBJECTIVES

The aim of this study was to evaluate the effects of tamoxifen on the weight and thickness of the urethral epithelium of castrated female rats.

METHODS

Forty castrated adult female Wistar-Hannover rats were randomly divided into two groups: Group I (n=20) in which the animals received only the vehicle (propylene glycol) and Group II (n=20) in which the rats received tamoxifen 250microg/day by gavage. After 30 days of treatment, all animals were sacrificed and the urethra was immediately removed for weighing. Next, the urethra was divided into the proximal and distal segments, which were fixed in 10% formaldehyde and submitted to routine histological techniques for morphometric study. The data were analyzed using the weighted minimum mean-square error method and Student's t-test for two independent samples (p<0.05).

RESULTS

There was a significant increase in the mean weight of the urethra in the rats of Group II compared to the control group, 32.0+/-2.0mg and 22.0+/-1.6mg, respectively (p<0.001). The mean thickness of the distal urethral epithelium of the animals treated with tamoxifen was significantly greater than that of the control group, 42.8+/-2.0microm and 36.6+/-1.5microm, respectively (p<0.001). There was no statistically significant difference between the two groups with respect to the epithelial thickness of the proximal urethra (p=0.514).

CONCLUSION

Treating castrated adult rats with 250microg/day of tamoxifen for 30 days may increase the weight of the urethra and the thickness of the distal urethral epithelium.

Increased alpha1-adrenergic activity in the rat bladder by depletion of ovarian hormones

PURPOSE

It is possible that postmenopausal loss of ovarian hormones leads to sensitization and/or over expression of alpha1-adrenergic receptors. The objective of this study was to determine whether ovariectomy enhances efferent transmission and, hence, increases contractility in the rat bladder by increasing alpha1-adrenergic receptors.

MATERIALS AND METHODS

This hypothesis was tested in 4 urethane anesthetized groups of female rats, including regularly cycling rats in metestrus and proestrus, and rats 4 months after ovariectomy with and without estradiol replacement, respectively. The bladder was catheterized through the urethra to measure intravesical pressure. The left femoral artery was also catheterized for local delivery of the nonspecific alpha1-adrenergic agonist phenylephrine, the alpha1-adrenergic antagonist prazosin, the specific alpha1A antagonist 5-methylurapidil or dimethyl sulfoxide (Sigma) in saline vehicle. In some rats bladder contractility was assessed by cystometry, followed by treatment with phenylephrine injected via the femoral artery. In other rats the bladder was denervated and a platinum electrode was wrapped around branches of the left pelvic nerve for electrical stimulation. The amplitude of micturition contractions and contractions evoked by phenylephrine or pelvic nerve stimulation was measured.

RESULTS

Micturition and phenylephrine evoked bladder contractions were significantly increased in ovariectomized rats without estradiol replacement. Prazosin significantly decreased contractions evoked by pelvic stimulation in a dose dependent manner. This decrease was significantly larger in ovariectomized rats without estradiol replacement compared to that in the other groups. The inhibition of stimulation evoked contractions by 5-methylurapidil was also greater in ovariectomized rats without estradiol replacement than in rats with estradiol replacement.

CONCLUSIONS

Results suggest that the depletion of ovarian hormones after ovariectomy enhances alpha1-adrenergic activity.

Androgen and estrogen receptor-mediated mechanisms of testosterone action in male rat pelvic autonomic ganglia

Although male reproductive function is primarily androgen dependent, many studies suggest that estrogens have direct actions on the male reproductive organs. Pelvic autonomic neurons provide the motor control of the internal reproductive organs and the penis and various properties of these neurons are affected by endogenous androgens. However, the possible role of estrogens at this site has not been examined. Here we have investigated the significance of estrogens produced by aromatization of testosterone (T) in the physiological actions of androgens on adult male rat pelvic ganglion neurons. Reverse transcriptase polymerase chain reaction (RT-PCR) studies showed that aromatase and both estrogen receptors (ERalpha and ERbeta) are expressed in these ganglia. Western blotting also showed that aromatase is expressed in male pelvic ganglia. Using immunohistochemical visualization, ERalpha was predominantly expressed by nitric oxide synthase (NOS)-positive parasympathetic pelvic ganglion neurons. In vivo studies showed that the decrease in pelvic ganglion soma size caused by gonadectomy could be prevented by administration of T or dihydrotestosterone (DHT), but not 17beta-estradiol (E2), showing that this maintenance action of testosterone is mediated entirely by androgenic mechanisms. However, in vitro studies of cultured pelvic ganglion neurons revealed that T, DHT and E each stimulated the growth of longer and more complex neurites in both noradrenergic and cholinergic NOS-expressing neurons. The effects of T were attenuated by either androgen or estrogen receptor antagonists, or by inhibition of aromatase. Together these studies demonstrate that estrogens are likely to be synthesized in the male pelvic ganglia, produced from T by local aromatase. The effects of androgens on axonal growth are likely to be at least partly mediated by estrogenic mechanisms, which may be important for understanding disease-, aging- and injury-induced plasticity in this part of the nervous system.

Efficacy of Selective Estrogen Receptor Modulators in Nude Mice Bearing Human Transitional Cell Carcinoma

OBJECTIVES

To evaluate estrogen receptors as a therapeutic target for human bladder cancer.

METHODS

The ability of the selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene to inhibit 5637 human transitional cell carcinoma cell proliferation was determined in vitro and in xenograft studies using 5637 cells in female athymic BALB/c nu/nu mice.

RESULTS

Treatment with tamoxifen, raloxifene, or the pure antiestrogen ICI 182,780 inhibited proliferation of 5637 cells in vitro. In the first xenograft study, raloxifene (10, 100, or 1000 microg/day) administered by oral gavage inhibited the growth of tumors compared with placebo or untreated controls (P <0.05). In a second experiment, tamoxifen (8.3, 125, or 1250 microg/day) delivered by time-release pellet inhibited tumor growth compared with placebo-treated controls (P <0.01). A comparison study in which tamoxifen (8.3 or 125 microg/day) or raloxifene (100 microg/day) was administered by slow-release pellet demonstrated that both SERMs reduced growth compared to placebo-treated controls (P <0.05), with comparable effectiveness. There was no detectable tumor in 17 of 30 treated mice. In all studies, average tumor volumes in SERM-treated animals declined over the course of treatment.

CONCLUSIONS

Selective estrogen receptor modulators inhibit the growth of 5637 transitional cell carcinoma cell xenografts, supporting the rationale to evaluate these agents as targeted therapeutics for patients with urothelial carcinoma.

Postnatal androgen deprivation dissociates the development of smooth muscle innervation from functional neurotransmission in mouse vas deferens

The pelvic autonomic nervous system is a target for circulating androgens in adults, with androgen exposure or deprivation affecting the structure and function of urogenital tract innervation. However, the critical period for androgen exposure to initially establish pelvic autonomic neuromuscular transmission has not been determined. We have examined the sympathetic innervation of the vas deferens in hypogonadal (hpg) mice that are deprived of androgens after birth but undergo normal prenatal sexual differentiation and remain androgen responsive throughout life. In vasa deferentia from hpg mice, purinergic excitatory junction potentials and contractions could not be elicited by electrical stimulation and P2X(1) purinoceptors could not be demonstrated by immunofluorescence. Moreover, a novel inhibitory nitrergic transmission developed. Administering testosterone to adult hpg mice restored purinergic excitatory transmission and P2X(1) purinoceptor immunofluorescence, and nitrergic inhibitory transmission was lost. Despite the deficit in excitatory neurotransmission in hpg mice, their vasa deferentia were innervated by numerous noradrenergic axons and pelvic ganglia appeared normal. In addition, noradrenergic contractions could be elicited by electrical stimulation. This study has revealed that postnatal androgen exposure has a profound effect on the development of excitatory transmission in vas deferens smooth muscle, primarily by a postjunctional action, but is not essential for development of the structural innervation of this organ. Our results also indicate that there is no postnatal critical period for androgen exposure to establish neuroeffector transmission and that postnatal androgen exposure can be delayed until adulthood, with little consequence for establishment of normal sympathetic neurotransmission.

Reproductive risk factors for incident bladder cancer: Iowa Women's Health Study

We studied the association between reproductive factors and bladder cancer incidence in a prospective cohort study of 37,459 Iowa women aged 55-69 years and initially free from cancer in 1986. Women reported reproductive history and were followed prospectively through 2003. After adjusting for age and smoking, there was an inverse association between age at menopause and incident bladder cancer (n = 192). Compared with menopause at age > or =48, the hazard ratio (HR) of bladder cancer was 1.32 (95% CI; 0.90-1.94) for menopause at 43-47, and 1.60 (95% CI; 1.06-2.39) for < or =42 (p-trend = 0.02). The associations were similar for ages at natural and surgical menopause. In addition, women with a history of bilateral oophorectomy had an increased risk of bladder cancer compared with those who did not undergo bilateral oophorectomy: HR = 1.58 (95% CI; 1.12, 2.22). Finally, there was an indication of a positive association between bladder cancer and shorter lifetime years of ovulation (p-trend = 0.09). There were no associations between incident bladder cancer and age at first birth, number of births, age at menarche, use of hormone replacement therapy or any other reproductive characteristics. This study provides evidence that increased risk of bladder cancer is associated with earlier age at menopause in postmenopausal women.

The effects of ovariectomy and estrogen replacement on acetylcholine release from nerve fibres and passive stretch-induced acetylcholine release in female rat bladder

AIMS

The present study investigated the effects of ovariectomy and estrogen replacement on the release of acetylcholine (Ach) from cholinergic neurons as well as on the tetrodotoxin (TTX)-insensitive stretch-induced Ach release in isolated rat detrusor. In addition, the above effects on rat micturition characteristics were also studied.

METHODS

Thirty female rats randomly received a sham operation, ovariectomy, or ovariectomy plus estrogen replacement. Using metabolic cages, micturition parameters were recorded. Then, in vitro functional experiments that included the measurements of nerve-mediated detrusor muscle contraction, Ach release from nerve fibres, and stretch-induced TTX-insensitive Ach release were performed. Ach release was measured using microdialysis and high-performance liquid chromatography.

RESULTS

Ovariectomized rats showed a significant decrease in voided volume and significant increase in 24-hr frequency of voiding. Ovariectomy caused the significant increase in both TTX-insensitive basal Ach release and TTX-insensitive stretch-induced Ach release. On the other hand, ovariectomy caused a significant decrease in Ach release from nerve fibres, resulting in the decrease in the contractile responses of detrusor muscle to electrical nerve stimulation. Estrogen replacement restored these alterations induced by ovariectomy.

CONCLUSIONS

Our findings showed that as a results of estrogen deficiency, Ach release from nerve fibres decreased, suggesting that this reduction of Ach released from cholinergic nerves may cause the decrease in detrusor contractility. Furthermore, this study also demonstrated that stretch-induced TTX-insensitive Ach release was increased by ovariectomy. This may be a contributing factor to the development of overactive bladder in elderly women.

Estrogen induced functional hypertrophy and increased force generation of the female rabbit bladder

AIMS

Estrogen is essential for physiological maintenance of the female urogenital tract. It is believed that alterations in female sex hormones play a major role in the etiology and response to urinary tract dysfunctions. In animal studies, ovariectomy (Ovx) results in smooth muscle (SM) weakness and atrophy whereas estrogen supplementation reverses these effects. Our study seeks to establish the mechanisms by which estrogen augmentation results in increased contractility.

METHODS

Twenty New Zealand White female rabbits were separated into five groups of four each. Group 1 served as control, rabbits of groups 2-5 were ovariectomized, group 2 ovariectomized received no estradiol, groups 3-5 were given 17-beta estradiol (1 mg/kg/day) by subcutaneous slow release tablet implant for 1, 3, and 7 days, respectively, beginning 2 weeks after Ovx. At the end of the experimental period, each rabbit was anesthetized and the urinary bladder was removed for contractile, histological, and biochemical studies.

RESULTS

Ovx resulted in significantly decreased bladder contractile function, whereas bladders tested after estradiol administration showed increased contractility. Ovx resulted in a decrease in SM/collagen ratio, whereas estrogen resulted in an increase. The estrogen receptor (ER) density significantly increased following Ovx. After 1 day of estrogen treatment, the ER density decreased significantly below control levels, but rose progressively during the estrogen treatment.

CONCLUSION

The present study demonstrates that estrogen supplementation mediates a "functional hypertrophy," that is a hypertrophy characterized by increased contractile responses to all forms of stimulation, and an increased ratio of SM/collagen.

Expression of estrogen receptors-alpha and -beta in bladder cancer cell lines and human bladder tumor tissue

BACKGROUND

Estrogen receptors (ERs) are known to mediate important physiologic responses as well as the growth of some tumors in response to estradiol stimulation. In a previous study the selective ER modulator raloxifene was shown to induce apoptosis in an ERbeta-positive bladder cancer cell line. However, the expression of ERbeta in human bladder cancer has not been thoroughly investigated.

METHODS

ERalpha and ERbeta expression in 224 bladder tumor samples was evaluated using tissue microarray and immunohistochemistry. Levels of ERalpha and ERbeta protein and mRNA expression were determined in several bladder cancer cell lines using quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blot analysis. The effect of estradiol and antiestrogen treatments on RT4 bladder cancer cell growth was determined by cell proliferation assays.

RESULTS

Analyses revealed that only 2 human bladder cancers weakly expressed ERalpha. In contrast, the expression of ERbeta was detected in 141 tumors (63%). ERbeta was expressed in 58% of WHO Grade 1 and 2 tumors, whereas 70% of Grade 3 tumors demonstrated expression (P = .085). Importantly, although only 53% and 55% of Ta and T1 tumors demonstrated ERbeta expression, 80% of T2, 81% of T3, and 75% of T4 tumors showed ERbeta expression. The differences in ERbeta expression between Ta/T1 and T2/T3/T4 tumors were found to be highly significant (P < .001). Metastatic transitional cell carcinomas had ERbeta expression (80%) comparable to that of muscle invasive bladder cancers. Western blot analysis detected ERbeta protein expression in each of the 5 bladder cancer cell lines tested, whereas no or very low levels of ERalpha were found. Quantitative RT-PCR revealed that higher levels of ERbeta than ERalpha mRNA were present in 5637, T-24, TSU-Pr1, and TCC-Sup bladder cancer cells, whereas ER-alpha mRNA levels were greater than ERbeta in RT4 cells. Treatment with 17beta-estradiol modestly increased RT4 cell growth, whereas the antiestrogens, 4-hydroxtamoxifen, raloxifene, or ICI 182,780 inhibited the growth of RT4 cells.

CONCLUSIONS

ERbeta is the dominant receptor expressed in bladder cancer cell lines and in the majority of human bladder tumors. Moreover, the degree of ERbeta expression increases with increasing stage and grade of differentiation. Antiestrogens have an inhibitory effect on the growth of bladder cancer cells in vitro.

Toremifene--a promising therapy for the prevention of prostate cancer and complications of androgen deprivation therapy

Deregulation of the estrogen axis in humans prompts a series of tissue-specific events. In the breast and prostate, alterations in estrogen signalling lead to genotypic and phenotypic molecular alterations that result in dysplastic cellular appearance, deregulated cell growth and carcinoma. In bone, decreased estrogen leads to increased osteoclastogenesis and bone resorption, decreased bone mineral density and a significant fracture risk. Toremifene is a selective estrogen receptor modulator that exerts pharmacological activity in the breast, bone and prostate. An intense interest in developing this agent for prostate cancer chemoprevention is based on the reduction of premalignant and malignant prostate lesions in a transgenic model of prostate cancer. Biological and clinical activity was demonstrated in Phase II trials by the prevention of progression to prostate cancer in men with high-grade prostate intraepithelial neoplasia and through suppression of bone turnover biomarkers and increased bone mineral density in men on androgen deprivation therapy for prostate cancer.

Role of estrogen in regulation of cellular differentiation: a study using human placental and rat Leydig cells

Estrogen classically is recognized as a growth-promoting hormone. Recent evidence suggests that estrogens are also involved in a wide variety of cellular and physiological functions involving the central nervous system, immune system, cardiovascular system and bone homeostasis. Our studies in cytotrophoblasts and BeWo cells, demonstrated that 17beta-estradiol induces terminal differentiation of placental trophoblasts directly and this differentiation is coupled with an increased production of TGFbeta1, which, in turn, affects telomerase activity and telomerase associated components at the level of hTERT. Furthermore, using rats treated in vivo with either EDS or estradiol and in vitro Leydig cell cultures, we proposed that 17beta-estradiol mediated down-regulation of collagen IV alpha4 expression could be one of the possible mechanisms for the inhibition of progenitor Leydig cell proliferation. In this review, we summarize the results from both the model systems, the human placental cytotrophoblast and rat Leydig cells to conclude that 17beta-estradiol has a unique stage-specific role in differentiation.

Plasticity of pelvic autonomic ganglia and urogenital innervation

Pelvic ganglia contain a mixture of sympathetic and parasympathetic neurons and provide most of the motor innervation of the urogenital organs. They show a remarkable sensitivity to androgens and estrogens, which impacts on their development into sexually dimorphic structures and provide an array of mechanisms by which plasticity of these neurons can occur during puberty and adulthood. The structure of pelvic ganglia varies widely among species, ranging from rodents, which have a pair of large ganglia, to humans, in whom pelvic ganglion neurons are distributed in a large, complex plexus. This plexus is frequently injured during pelvic surgical procedures, yet strategies for its repair have yet to be developed. Advances in this area will come from a better understanding of the effects of injury on the cellular signaling process in pelvic neurons and also the role of neurotrophic factors during development, maintenance, and repair of these axons.

A dose-dependent dual effect of oestrogen on voiding in the male mouse?

OBJECTIVES

To explore the effect of different degrees of oestrogenization on male voiding, by treating adult castrated and 5alpha-dihydrotestosterone (DHT)-maintained male mice with different doses of oestrogens, as exposure of male mice to excessive amounts of oestrogens can cause bladder outlet obstruction (BOO); in addition, male mice lacking oestrogen receptor (ER)alpha (ERKO) or ERbeta (BERKO) were studied to assess the importance of ER subtypes.

MATERIALS AND METHODS

Castrated, DHT-maintained adult mice were treated with 17beta-oestradiol (E(2); 50 and 250 microg/kg) or oestrone (E(1); 5, 50 and 500 microg/kg) daily for 10 days. Control mice were treated only with the vehicle. BERKO and ERKO mice, and their wild-type littermates used as their controls, remained untreated. Under anaesthesia, the bladder and distal urethra were exposed to record simultaneously the bladder pressure and urinary flow rate from the distal urethra.

RESULTS

E(2)-treated mice showed obstructive voiding, seen as increased bladder pressure, decreased average flow rate and prolonged micturition time. This was also evident when a high dose (500 microg/kg) of E(1) was used. After treatment with a dose of 50 microg/kg, the urodynamic variables were similar to those in the control mice. Surprisingly, after treatment with a low dose (5 microg/kg) all urodynamic variables improved. There was a minor increase in the bladder pressure in BERKO mice; ERKO mice had a significantly lower urinary flow rate.

CONCLUSIONS

High doses of oestrogens caused BOO in castrated, DHT-maintained male mice. A small dose of E(1) had a positive effect on voiding, suggesting that oestrogens are needed for normal male voiding. Reduced urinary flow rates in ERKO mice suggest that oestrogen effects on voiding are mediated at least partly via ERalpha.

Effects of estradiol-17β, testosterone and a black cohosh preparation on bone and prostate in orchidectomized rats

Estradiol (E2) and testosterone (T) effectively prevent orchidectomy (orx) induced osteoporosis. T, however, stimulates prostate proliferation which may lead to malignancy. We showed that a Cimicifuga racemosa (CR) preparation had bone-sparing effects without exerting estrogenic effects in the uterus. We studied therefore whether a CR preparation has also antiosteoporotic effects in orx rats substituted with E2, T or CR via pelleted food over a period of 3 months. Average daily intake per animal was: T: 25 mg; E2: 0.325 mg, CR low dose: 33 mg; CR high dose: 133 mg. E2, T and CR at the high dose partially prevented development of osteoporosis as measured by quantitative computer tomography in the metaphysis of the tibia. E2, but not T or CR reduced serum osteocalcin and the metabolic products of collagen-1alpha1. Gene expression of collagen-1alpha1 and tartrate-resistant acid phosphatase was decreased by E2 and the higher dose of the CR extract but increased in the T-treated animals. In the prostate T inhibited androgen receptor, estrogen receptor alpha and insulin-like growth factor-1 gene expression but stimulated the expression of the ERbeta gene. These effects were not shared by E2 or both doses of the CR extract. It is concluded that E2, T and CR exert antiosteoporotic effects in the metaphysis of the tibia of orx rats. T has profound effects in the prostate which were not seen in the E2- and CR-treated animals. Therefore, the Cimicifuga racemosa extract BNO 1055 may be useful to prevent osteoporosis in aged male patients with reduced testosterone production.

Experimental diabetes has adverse effects on the differentiation of ventral prostate during sexual maturation of rats

Diabetes mellitus of both type I (insulin-dependent) and type II (noninsulin-dependent) has adverse effects on male sexual and reproductive functions in adolescent boys and men, which include impairment of spermatogenesis, reduced sperm count, serum testosterone and seminal fluid volume, impotency, and loss of libido. Streptozotocin (STZ)-induced diabetes in rats provides a relevant model to study reproductive dysfunction under diabetic conditions, as they exhibit a number of deficits in reproductive function that resemble those seen in human diabetics. Therefore, the present investigation is aimed to understand the effects of STZ diabetes on the structure and development of ventral prostate during the critical period of sexual maturation in rats. Prepubertal (40-days-old) male Wistar rats were made diabetic by single injection of STZ (120 mg/kg body weight, intraperitoneally). Induction of diabetes was confirmed by serum insulin titer, hyperglycemia, and polyuria. To another set of STZ-diabetic rats, after 3 days of diabetes induction, insulin was replaced at a dose of 3 U/100 g body weight, subcutaneously in two equally divided doses at 8:00 AM and 6:00 PM. Diabetes caused regression of prostate, leading to a decrease in the absolute weight. Histologically, glandular epithelium has undergone shrinkage with transformation of acinar cells into low cuboidal type with less prominent secretory granules and blebs. Nevertheless, the secretory activity was not totally abolished. Interstitial space was increased due to shrinkage of glandular epithelium. Histomorphometric studies on the tubular diameter, volume and surface density of acinar epithelium, lumen, and stroma also support regressive changes in prostate. Insulin replacement prevented the detrimental effects of diabetes partially. These findings implicate the adverse effects of STZ diabetes on the differentiation of ventral prostate during sexual maturation.

Pure estrogenic effect of benzophenone-2 (BP2) but not of bisphenol A (BPA) and dibutylphtalate (DBP) in uterus, vagina and bone

Contradictory results whether the endocrine disrupters (ED) benzophenone-2 (BP2), bisphenol A (BPA) and dibutylphtalate (DBP) exert estrogenic effects have been published. Selective estrogen receptor modulators (SERMs) exert estrogenic effects in some but not in all organs and ED may be SERMs. Therefore, we studied their binding properties to recombinant ERalpha and ERbeta protein and their effects in the uterus, vagina and bone of ovariectomized rats. BP2 bound to both receptor subtypes, while BPA had a relatively high ERbeta selectivity. DBP did not bind to ERalpha but with a low affinity to ERbeta. In the uterus, only E2 and BP2 increased uterine weight and the complement C3 but decreased ERbeta gene expression. Discrete effects of BPA and DBP in the uterus were found upon histological examination. In the vagina, BP2 but not BPA and DBP had clear estrogenic effects. E2 and BP2 had antiosteoporotic effects in the metaphysis of the tibia. The serum surrogate parameters of bone metabolism, i.e. osteocalcin and the cross (rat) laps were significantly reduced by E2, an effect shared with BP2 but not by the two other EDs.

THE CONCLUSION

BP2 acts as ERalpha and ERbeta agonist mimicking effects of E2, while the effects of BPA and DBP are not pure estrogenic.

Short-term functional and neuroregenerative response of the urethra to ovariectomy and vaginal distension in female rats

The objective of this study was to investigate the effects of ovariectomy (OVX) and vaginal distension (VD) on leak point pressure (LPP) and pudendal nerve regenerative response in the female rat. Twenty rats underwent OVX 3 days prior to either VD or sham distension. Seventeen rats did not receive OVX but underwent either VD or sham distension. Four days after distension, LPP testing was performed. In situ hybridization for beta(II) tubulin mRNA, an indicator of the neuroregenerative response, was performed on motoneurons of the pudendal nerve. In the non-OVX group, LPP was significantly decreased after VD. After OVX, the difference in LPP between VD and sham rats did not quite reach the level of statistical significance. There was a statistically significant interaction between the effects of OVX and VD on LPP. There was no significant difference in in situ hybridization results between any of the groups. No neuroregenerative response of motoneurons of the pudendal nerve was observed after either VD or OVX.

Rapid actions of estradiol on cyclic amp response-element binding protein phosphorylation in dorsal root ganglion neurons

Actions of gonadal steroids have not been widely investigated in the peripheral nervous system, although many dorsal root ganglion (DRG) and autonomic pelvic ganglion (PG) neurons express estrogen receptors (ERs). We have studied the effects of 17beta-estradiol exposure on cultured DRG and PG neurons from adult rats. Western blotting analysis of DRG extracts detected phosphorylation of ERK1 and ERK2 (extracellular signal-regulated kinases) that peaked 10 min after exposure to 17beta-estradiol. These extracts contain both neurons and glia; therefore, to determine if this response occurred in DRG neurons, we developed an immunocytochemical method to specifically measure activation in individual neurons. These measurements showed that estradiol increased phosphorylation of CREB (cyclic AMP response-element binding protein), which was consistently blocked by the ERK pathway inhibitor PD98059 but not by the inhibitors of phosphatidylinositol 3-kinase, wortmannin and LY294002. 17beta-Estradiol activation of CREB in DRG neurons was reduced by the ER antagonist, ICI182780. In contrast, in PG neurons estradiol did not affect CREB phosphorylation, highlighting a difference in E2 responses in different populations of peripheral neurons. This study has shown that estrogens can rapidly activate signaling pathways associated with CREB-mediated transcriptional regulation in sensory neurons. As these pathways also mediate many effects of neurotrophic factors, changes in estrogen levels (e.g. during puberty, pregnancy or menopause) could have broad-ranging genomic and non-genomic actions on urogenital pain sensation and reflex pathways.

Estrogen receptor subtypes and afferent signaling in the bladder

PURPOSE

The influence of estrogen on bladder function has been the subject of several experimental and clinical studies. In addition to the well-known estrogen receptor (ER)alpha, recently the ER subtype ERbeta was discovered. We investigated potential changes in bladder function in mice lacking either 1 or both receptor subtypes compared with WT mice.

MATERIALS AND METHODS

Female mice lacking genes for ERalpha (ERKO), ERbeta (BERKO) or both and their WT littermates were used for the study. Continuous cystometry in awake animals was performed before and after intravesical administration of capsaicin. In addition, in vitro responses to electrical field stimulation before and after incubation with scopolamine and alpha,beta-methylene adenosine triphosphate, and to carbachol were investigated.

RESULTS

Control cystometry revealed no significant difference in urodynamic parameters among all strains. After capsaicin instillation the micturition interval and volume decreased, and micturition pressure increased in WT, ERbeta and 2 gene mice, while no changes were seen in ERKO mice. In vitro contractility was similar in all groups. Incubation with scopolamine and alpha,beta-methylene adenosine triphosphate led to significant decreases in the response to electrical field stimulation. There was no difference in the response to carbachol among the groups.

CONCLUSIONS

The lack of ERalpha and/or ERbeta had little effect on in vitro contractility or on continuous cystometry in awake animals. The lack of response to capsaicin instillation in ERKO suggests that ER subtypes are important for vanilloid receptor function and mechano-afferent signaling.

The effect of ovariectomy and estradiol on rabbit bladder smooth muscle contraction and morphology

PURPOSE

The bladder can be considered a target organ for the actions of estrogen. Decreases in circulating estrogen after menopause have been associated with bladder dysfunctions, including incontinence and detrusor instability. We determined the effects of estrogen on rabbit bladder contractile function and morphology.

MATERIALS AND METHODS

Female New Zealand White rabbits were ovariectomized or sham operated and treated with vehicle or estradiol (1 mg/kg weekly) for 5 weeks. Serum estradiol concentration was monitored every 2 weeks. After treatment each rabbit was anesthetized, the bladder was catheterized, cystometry was performed, and the bladder was removed for contractile and morphological studies. Apoptosis in paraffin embedded rabbit bladder tissue was detected using in situ end-labeling, specifically terminal deoxynucleotidyl-transferase nick end labeling or the TUNEL assay.

RESULTS

Ovariectomy resulted in a 50% decrease in circulating estrogen and estradiol treatment resulted in a 5-fold increase. Ovariectomy had no significant effects on bladder capacity, micturition pressure or bladder weight; whereas estradiol treatment resulted in significant increases in bladder capacity and bladder weight. Ovariectomy resulted in a decreased rate of tension generation in response to field stimulation, carbachol and KCl. Estradiol resulted in increased contractile responses to FS and carbachol, and an increased rate of tension generation for carbachol and KCl. Histologically ovariectomy resulted in significant urothelial apoptosis, which was not present in the sham operated or estradiol treated groups. Estradiol treatment resulted in the appearance of large cytoplasmic vacuoles in the urothelium and significant smooth muscle hypertrophy.

CONCLUSIONS

These findings demonstrate that bladder function and structure can be significantly affected by modulating the circulating estrogen level. In addition, estrogen given in pharmacological doses can have a significant hypertrophic effect on bladder smooth muscle, resulting in increased contractile function.

Estrogen receptor expression in lumbosacral dorsal root ganglion cells innervating the female rat urinary bladder

We have investigated whether bladder afferent neurons are likely to be targets for circulating estrogens by mapping estrogen receptor (ER) distribution in lumbosacral dorsal root ganglia (DRG) of adult female rats. Sensory neurons innervating either the detrusor or trigone regions were identified by application of fluorescent retrograde tracer dyes to the bladder wall. Labelled neurons were classified by their immunoreactivity for either type of ER (ERalpha or ERbeta) and further compared with subpopulations of neurons containing substance P, calcitonin gene-related peptide and vanilloid receptor (a marker of polymodal nociceptors). Both ER types were expressed in numerous sensory neurons of either upper lumbar (L1/L2) or lower lumbar/sacral (L6/S1) ganglia and there was almost complete coexpression of ERalpha and ERbeta. ER-positive neurons were mainly small-medium size (18-25-microm diameter), indicating that they may be nociceptors and/or supply visceral targets. Most bladder-projecting neurons expressed ERs and the majority of these also expressed neuropeptides or vanilloid receptor. Afferent neurons supplying detrusor and trigone regions had similar immunohistochemical features. About a third of the bladder-projecting neurons expressed both ER and vanilloid receptor, suggesting a mechanism by which estrogens could influence bladder pain. The prevalence of different chemical classes of ER-positive bladder-projecting neurons was reflected throughout the entire population of neurons in dorsal root ganglia of these spinal levels, suggesting that neurons supplying other pelvic visceral targets may have similar chemical profiles. These results suggest that many functional classes of sensory neurons innervating the lower urinary tract are likely to be targets for circulating estrogens, including many nociceptor neurons. The coexistence of ERalpha and ERbeta suggests a broad range of potential mechanisms by which estrogens may exert their genomic effects in this system.

Expression of estrogen receptor alpha and beta in myometrium of premenopausal and postmenopausal women

Although a clear role for estrogen receptor (ER) alpha has been established, the contribution of ERbeta in estrogen-dependent development, growth and functions of the myometrium is not understood. As a first step towards understanding the role of ERbeta, we have examined the expression of ERalpha and ERbeta in the human myometrium. With competitive RT-PCR assays, the level of ERbeta mRNA was 10-200 times lower than that of ERalpha mRNA in both premenopausal and postmenopausal myometrium. In premenopausal myometrium, the expression pattern of ERbeta mRNA during the menstrual cycle was similar to that of ERalpha mRNA, with highest levels in peri-ovulatory phase. In postmenopausal myometrium, ERbeta mRNA was significantly higher than it was in premenopausal myometrium, while the level of ERalpha mRNA was lower. The net result was a change in the ratio of ERbeta to ERalpha mRNA expression. The ratio changed from 0.6-1.5 in premenopausal to 2.5-7.6 in postmenopausal myometrium. In premenopausal women, the gonadotropin releasing hormone analogue, leuprorelin acetate, elicited a decrease in ERalpha and an increase in ERbeta mRNA expression to cause a postmenopausal receptor phenotype. Estradiol, on the other hand, reversed ERalpha and ERbeta mRNA expression and their ratio in postmenopausal myometrium to those of premenopausal myometrium. Immunohistochemical staining and Western blot analysis of ERalpha and ERbeta with semiquantitative analysis showed good agreement between mRNA and protein levels. The data indicate that coordinated expression of ERalpha and ERbeta might be necessary for normal estrogen action in myometrium. Furthermore, estrogen appears a dominant regulator of both receptors in the myometrium.

Phytoestrogens for hormone replacement therapy?

Due to some severe side effects "classical" hormone replacement therapy (HRT) is currently being challenged by a therapy with phytoestrogens. Particularly soy and red clover derived isoflavones are advertised as selective estrogen receptor modulators (SERMs) with only desired and no undesired estrogenic effects. Evidence that this is the case however is scarce. Most studies investigating climacteric complaints did not find beneficial effects. A proposed beneficial effect on mammary cancer is unproven. The majority of studies however indicate an antiosteoporotic effect of isoflavones, while putative beneficial effects in the cardiovascular system are questionable due to the fact that estradiol which--like isoflavones--increase HDL and decrease LDL concentrations appear not to prevent arteriosclerosis in the human. In the urogenital tract, including the vagina, soy and red clover derived isoflavones are without effects. Cimicifuga racemosa extracts are traditionally used for the treatment of climacteric complaints. Evidence is now available that the yet unknown compounds in Cimicifuga racemosa extracts prevent climacteric complaints and may also have antiosteoporotic effects.