Ovarian testosterone secretion during perimenopause

Increased Local Testosterone Levels Alter Human Fallopian Tube mRNA Profile and Signaling

Fallopian tube epithelium (FTE) plays a critical role in reproduction and can be the site where High Grade Serous Ovarian Carcinoma (HGSOC) originates. Tumorigenic oviductal cells, which are the murine equivalent of human fallopian tube secretory epithelial cells (FTSEC), enhance testosterone secretion by the ovary when co-cultured with the ovary, suggesting that testosterone is part of the signaling axis between the ovary and FTSEC. Furthermore, testosterone promotes proliferation of oviductal cells. Oral contraceptives, tubal ligation, and salpingectomy, which are all protective against developing ovarian cancer, also decrease circulating levels of androgen. In the current study, we investigated the effect of increased testosterone on FTE and found that testosterone upregulates wingless-type MMTV integration family, member 4 (WNT4) and induces migration and invasion of immortalized human fallopian tube cells. We profiled primary human fallopian tissues grown in the microfluidic system SOLO-microfluidic platform –(MFP) by RNA sequencing and found that p53 and its downstream target genes, such as paired box gene 2 (PAX2), cyclin-dependent kinase inhibitor 1A (CDK1A or p21), and cluster of differentiation 82 (CD82 or KAI1) were downregulated in response to testosterone treatment. A microfluidic platform, the PREDICT-Multi Organ System (PREDICT-MOS) was engineered to support insert technology that allowed for the study of cancer cell migration and invasion through Matrigel. Using this system, we found that testosterone enhanced FTE migration and invasion, which was reversed by the androgen receptor (AR) antagonist, bicalutamide. Testosterone also enhanced FTSEC adhesion to the ovarian stroma using murine ovaries. Overall, these results indicate that primary human fallopian tube tissue and immortalized FTSEC respond to testosterone to shift expression of genes that regulate invasion, while leveraging a new strategy to study migration in the presence of dynamic fluid flow.

Neurodegenerative Disease: Roles for Sex, Hormones, and Oxidative Stress

Neurodegenerative diseases cause severe impairments in cognitive and motor function. With an increasing aging population and the onset of these diseases between 50 and 70 years, the consequences are bound to be devastating. While age and longevity are the main risk factors for neurodegenerative diseases, sex is also an important risk factor. The characteristic of sex is multifaceted, encompassing sex chromosome complement, sex hormones (estrogens and androgens), and sex hormone receptors. Sex hormone receptors can induce various signaling cascades, ranging from genomic transcription to intracellular signaling pathways that are dependent on the health of the cell. Oxidative stress, associated with aging, can impact the health of the cell. Sex hormones can be neuroprotective under low oxidative stress conditions but not in high oxidative stress conditions. An understudied sex hormone receptor that can induce activation of oxidative stress signaling is the membrane androgen receptor (mAR). mAR can mediate nicotinamide adenine dinucleotide-phosphate (NADPH) oxidase (NOX)-generated oxidative stress that is associated with several neurodegenerative diseases, such as Alzheimer disease. Further complicating this is that aging can alter sex hormone signaling. Prior to menopause, women experience more estrogens than androgens. During menopause, this sex hormone profile switches in women due to the dramatic ovarian loss of 17β-estradiol with maintained ovarian androgen (testosterone, androstenedione) production. Indeed, aging men have higher estrogens than aging women due to aromatization of androgens to estrogens. Therefore, higher activation of mAR-NOX signaling could occur in menopausal women compared with aged men, mediating the observed sex differences. Understanding of these signaling cascades could provide therapeutic targets for neurodegenerative diseases.

Neuroprotective and neurotoxic outcomes of androgens and estrogens in an oxidative stress environment

BACKGROUND

The role of sex hormones on cellular function is unclear. Studies show androgens and estrogens are protective in the CNS, whereas other studies found no effects or damaging effects. Furthermore, sex differences have been observed in multiple oxidative stress-associated CNS disorders, such as Alzheimer's disease, depression, and Parkinson's disease. The goal of this study is to examine the relationship between sex hormones (i.e., androgens and estrogens) and oxidative stress on cell viability.

METHODS

N27 and PC12 neuronal and C6 glial phenotypic cell lines were used. N27 cells are female rat derived, whereas PC12 cells and C6 cells are male rat derived. These cells express estrogen receptors and the membrane-associated androgen receptor variant, AR45, but not the full-length androgen receptor. N27, PC12, and C6 cells were exposed to sex hormones either before or after an oxidative stressor to examine neuroprotective and neurotoxic properties, respectively. Estrogen receptor and androgen receptor inhibitors were used to determine the mechanisms mediating hormone-oxidative stress interactions on cell viability. Since the presence of AR45 in the human brain tissue was unknown, we examined the postmortem brain tissue from men and women for AR45 protein expression.

RESULTS

Neither androgens nor estrogens were protective against subsequent oxidative stress insults in glial cells. However, these hormones exhibited neuroprotective properties in neuronal N27 and PC12 cells via the estrogen receptor. Interestingly, a window of opportunity exists for sex hormone neuroprotection, wherein temporary hormone deprivation blocked neuroprotection by sex hormones. However, if sex hormones are applied following an oxidative stressor, they exacerbated oxidative stress-induced cell loss in neuronal and glial cells.

CONCLUSIONS

Sex hormone action on cell viability is dependent on the cellular environment. In healthy neuronal cells, sex hormones are protective against oxidative stress insults via the estrogen receptor, regardless of sex chromosome complement (XX, XY). However, in unhealthy (e.g., high oxidative stress) cells, sex hormones exacerbated oxidative stress-induced cell loss, regardless of cell type or sex chromosome complement. The non-genomic AR45 receptor, which is present in humans, mediated androgen's damaging effects, but it is unknown which receptor mediated estrogen's damaging effects. These differential effects of sex hormones that are dependent on the cellular environment, receptor profile, and cell type may mediate the observed sex differences in oxidative stress-associated CNS disorders.

Endocrine profile of the VCD-induced perimenopausal model rat

During the transition to menopause, women experience a variety of physical and psychological symptoms that are directly or indirectly linked to changes in hormone secretion. Establishing animal models with intact ovaries is essential for understanding these interactions and finding new therapeutic targets. In this study, we assessed the endocrine profile, as well as the estrous cycle, in the 4-vinylcyclohexene diepoxide (VCD)-induced follicular depletion rat model in 10-day intervals over 1 month to accurately establish the best period for studies of the transition period. Twenty-eight-day-old female rats were injected daily with VCD or oil s.c. for 15 days and euthanized in the diestrus phase approximately 70, 80, 90 and 100 days after the onset of treatment. The percentage of rats showing irregular cycles and the plasma level of FSH increased only in the 100-day VCD group. Plasma anti-Müllerian hormone (AMH) and progesterone were lower in all VCD groups compared to control groups, while estradiol remained unchanged or higher. As in control groups, dihydrotestosterone (DHT) progressively decreased in the 70-90-day VCD groups; however, it was followed by a sharp increase only in the 100-day VCD group. No changes were found in plasma corticosterone, prolactin, thyroid hormones or luteinizing hormone. Based on the estrous cycle and endocrine profile, we conclude that 1) the time window from 70 to 100 days is suitable to study a perimenopause-like state in this model, and 2) regular cycles with low progesterone and AMH and normal FSH can be used as markers of the early/mid-transition period, whereas irregular cycles associated with higher FSH and DHT can be used as markers of the late transition period to estropause.

Sex hormones and stroke: Beyond estrogens

Stroke risk and poor stroke outcomes in postmenopausal women have usually beeen attributed to decreased levels of estrogen. However, two lines of evidence suggest that this hormone may not be solely responsible for elevated stroke risk in this population. First, the increased risk for CVD and stroke occurs much earlier than menopause at a time when estrogen levels are not yet reduced. Second, estrogen therapy has not successfully reduced stroke risk in all studies. Other sex hormones may therefore also contribute to stroke risk. Prior to menopause, levels of the gonadotrophin Follicle Stimulating Hormone (FSH) are elevated while levels of the gonadal peptide inhibin are lowered, indicating an overall decrease in ovarian reserve. Similarly, reduced estrogen levels at menopause significantly increase the ratio of androgens to estrogens. In view of the evidence that androgens may be unfavorable for CVD and stroke, this elevated ratio of testosterone to estrogen may also contribute to the postmenopause-associated stroke risk. This review synthesizes evidence from different clinical populations including natural menopause, surgical menopause, women on chemotherapy, and preclinical stroke models to dissect the role of ovarian hormones and stroke risk and outcomes.

NADPH Oxidase Mediates Membrane Androgen Receptor-Induced Neurodegeneration

Oxidative stress (OS) is a common characteristic of several neurodegenerative disorders, including Parkinson disease (PD). PD is more prevalent in men than in women, indicating the possible involvement of androgens. Androgens can have either neuroprotective or neurodamaging effects, depending on the presence of OS. Specifically, in an OS environment, androgens via a membrane-associated androgen receptor (mAR) exacerbate OS-induced damage. To investigate the role of androgens on OS signaling and neurodegeneration, the effects of testosterone and androgen receptor activation on the major OS signaling cascades, the reduced form of NAD phosphate (NADPH) oxidase (NOX)1 and NOX2 and the Gαq/inositol trisphosphate receptor (InsP3R), were examined. To create an OS environment, an immortalized neuronal cell line was exposed to H2O2 prior to cell-permeable/cell-impermeable androgens. Different inhibitors were used to examine the role of G proteins, mAR, InsP3R, and NOX1/2 on OS generation and cell viability. Both testosterone and DHT/3-O-carboxymethyloxime (DHT)-BSA increased H2O2-induced OS and cell death, indicating the involvement of an mAR. Furthermore, classical AR antagonists did not block testosterone's negative effects in an OS environment. Because there are no known antagonists specific for mARs, an AR protein degrader, ASC-J9, was used to block mAR action. ASC-J9 blocked testosterone's negative effects. To determine OS-related signaling mediated by mAR, this study examined NOX1, NOX2, Gαq. NOX1, NOX2, and the Gαq complex with mAR. Only NOX inhibition blocked testosterone-induced cell loss and OS. No effects of blocking either Gαq or G protein activation were observed on testosterone's negative effects. These results indicate that androgen-induced OS is via the mAR-NOX complex and not the mAR-Gαq complex.

Conditions and possible mechanisms of VCD-induced ovarian failure

Perimenopause is an important period in women's lives, in which they experience a series of physiological changes. Current animal models of perimenopause fail to adequately replicate this particular stage in female life, while current in vitro models are too simplistic and cannot account for systemic effects. Neither the naturally-ageing animal model, nor the ovariectomised animal model, mimic the natural transitional process that is the menopause. In vivo and in vitro studies have confirmed that the occupational chemical, 4-vinylcyclohexene diepoxide (VCD), can cause selective destruction of the ovarian primordial and primary follicles of rats and mice by accelerating the apoptotic process, which successfully mimics the perimenopausal state in women. However, it is the in vivo VCD-induced rodent perimenopausal models that are currently the most widely used in research, rather than any of the available in vitro models. Studies on the mechanisms involved have found that VCD induces ovotoxicity via interference with the c-kit/kit ligand and apoptotic signalling pathways, among others. Overall, the VCD-induced perimenopausal animal models have provided some insight into female perimenopause, but they are far from ideal models of the human situation.

Acute Exposure to Di(2-Ethylhexyl) Phthalate in Adulthood Causes Adverse Reproductive Outcomes Later in Life and Accelerates Reproductive Aging in Female Mice

Humans are ubiquitously exposed to di(2-ethylhexyl) phthalate (DEHP), which is an environmental toxicant incorporated in consumer products. Studies have shown that DEHP targets the ovary to disrupt essential processes required for reproductive and nonreproductive health. Specifically, 10-day exposure to DEHP accelerates primordial follicle recruitment and disrupts estrous cyclicity in adult mice. However, it is unknown if these effects on folliculogenesis and cyclicity following acute DEHP exposure can have permanent effects on reproductive outcomes. Further, the premature depletion of primordial follicles can cause early reproductive senescence, and it is unknown if acute DEHP exposure accelerates reproductive aging. This study tested the hypothesis that acute DEHP exposure causes infertility, disrupts estrous cyclicity, alters hormone levels, and depletes follicle numbers by inducing atresia later in life, leading to accelerated reproductive aging. Adult CD-1 mice were orally dosed with vehicle or DEHP (20 μg/kg/day-500 mg/kg/day) daily for 10 days, and reproductive outcomes were assessed at 6 and 9 months postdosing. Acute DEHP exposure significantly altered estrous cyclicity compared to controls at 6 and 9 months postdosing by increasing the percentage of days the mice were in estrus and metestrus/diestrus, respectively. DEHP also significantly decreased inhibin B levels compared to controls at 9 months postdosing. Further, DEHP significantly increased the BAX/BCL2 ratio in primordial follicles leading to a significant decrease in primordial and total follicle numbers compared to controls at 9 months postdosing. Collectively, the adverse effects present following acute DEHP exposure persist later in life and are consistent with accelerated reproductive aging.

Sex disparity in colonic adenomagenesis involves promotion by male hormones, not protection by female hormones

It recently has been recognized that men develop colonic adenomas and carcinomas at an earlier age and at a higher rate than women. In the Apc(Pirc/+) (Pirc) rat model of early colonic cancer, this sex susceptibility was recapitulated, with male Pirc rats developing twice as many adenomas as females. Analysis of large datasets revealed that the Apc(Min/+) mouse also shows enhanced male susceptibility to adenomagenesis, but only in the colon. In addition, WT mice treated with injections of the carcinogen azoxymethane (AOM) showed increased numbers of colonic adenomas in males. The mechanism underlying these observations was investigated by manipulation of hormonal status. The preponderance of colonic adenomas in the Pirc rat model allowed a statistically significant investigation in vivo of the mechanism of sex hormone action on the development of colonic adenomas. Females depleted of endogenous hormones by ovariectomy did not exhibit a change in prevalence of adenomas, nor was any effect observed with replacement of one or a combination of female hormones. In contrast, depletion of male hormones by orchidectomy (castration) markedly protected the Pirc rat from adenoma development, whereas supplementation with testosterone reversed that effect. These observations were recapitulated in the AOM mouse model. Androgen receptor was undetectable in the colon or adenomas, making it likely that testosterone acts indirectly on the tumor lineage. Our findings suggest that indirect tumor-promoting effects of testosterone likely explain the disparity between the sexes in the development of colonic adenomas.

Sympathetic regulation of estradiol secretion from the ovary

It is well known that hormone secretion from endocrine glands is regulated by hierarchical feedback mechanisms. However, although Cannon revealed in the 1920s that sympathoadrenal medullary function increased during emergency situations, no studies on the autonomic nervous regulation of hormone secretion have been undertaken for many years. In the past 40 years, the autonomic nervous regulation of insulin secretion from the pancreas, gastrin secretion from the stomach, glucocorticoid secretion from the adrenal cortex, etc., has been demonstrated. Estradiol secretion from the ovary is strongly controlled by the hypothalamic-pituitary-ovarian axis, and its possible regulation by autonomic nerves has been largely unnoticed. Some histological studies have revealed rich adrenergic sympathetic innervation in the ovary. Recently, it has been demonstrated that the activation of the sympathetic nerves to the ovary directly reduces estradiol secretion from the ovary. This article reviews physiological and morphological studies, primarily in rats, on the sympathetic regulation of estradiol secretion from the ovary.

Voice and handgrip strength predict reproductive success in a group of indigenous African females

Evolutionary accounts of human traits are often based on proxies for genetic fitness (e.g., number of sex partners, facial attractiveness). Instead of using proxies, actual differences in reproductive success is a more direct measure of darwinian fitness. Certain voice acoustics such as fundamental frequency and measures of health such as handgrip strength correlate with proxies of fitness, yet there are few studies showing the relation of these traits to reproduction. Here, we explore whether the fundamental frequency of the voice and handgrip strength account for differences in actual reproduction among a population of natural fertility humans. Our results show that both fundamental frequency and handgrip strength predict several measures of reproductive success among a group of indigenous Namibian females, particularly amongst the elderly, with weight also predicting reproductive outcomes among males. These findings demonstrate that both hormonally regulated and phenotypic quality markers can be used as measures of darwinian fitness among humans living under conditions that resemble the evolutionary environment of Homo sapiens. We also argue that these findings provide support for the Grandmother Hypothesis.

Diets and hormonal levels in postmenopausal women with or without breast cancer

The role of diet in breast cancer (BC) risk is unclear. Fiber could reduce BC risk, through the enterohepatic circulation of estrogens. We examined the relationship between diet and sex hormones in postmenopausal women with or without BC. Thirty-one postmenopausal women (10 omnivores, 11 vegetarians, and 10 BC omnivores) were recruited. Dietary records (5 days) and hormone levels (3 days) were evaluated on 4 occasions over 1 yr. Vegetarians showed a lower fat/fiber ratio, a higher intake of total and cereal fiber (g/d)/body weight (kg), a significantly lower level of plasma estrone-sulfate, estradiol, free-estradiol, free-testosterone, and ring D oxygenated estrogens, and a significantly higher level of sex-hormone-binding-globulin than BC subjects. Fiber was consumed in slightly larger amounts by omnivores than by BC subjects. Omnivores had significantly lower plasma testosterone and estrone-sulfate but higher sex-hormone-binding-globulin than BC subjects. No difference was found for the urinary 16-oxygenated estrogens. However, the 2-MeO-E1/2-OH-E1 ratio was significantly lower in omnivores than in BC group. This ratio is positively associated with the fat/fiber ratio. In conclusion, testosterone may contribute to causing alterations in the levels of catechol estrogens and 16-oxygenated estrogens. The fat/fiber ratio appears to be useful in evaluating dietary effects on estrogen metabolism.

Ovarian volumes among women with endometrial carcinoma: associations with risk factors and serum hormones

OBJECTIVES

Data suggest that post-menopausal women with larger ovaries are at increased risk for endometrial carcinoma; however, analyses comparing ovarian volume to serum hormone levels are limited. Accordingly, we assessed ovarian volumes in relation to serum sex hormone levels among post-menopausal women with endometrial carcinoma who participated in a multi-center case-control study.

METHODS

Data for established risk and protective factors for endometrial carcinoma were collected via in-person interviews. Ovarian volumes were estimated from pathology reports. Associations between exposures and age-adjusted ovarian volumes were analyzed for 175 cases with available data. For a subset of 135 cases, we analyzed relationships between ovarian volume, adjusted for age and body mass index (BMI), and serum hormone levels by analysis of variance.

RESULTS

Ovarian volume declined progressively from 1.83 cm3 among women ages 55-59 years to 1.23 cm3 among women age 70 years or older (p-trend=0.02). Larger ovarian volume was associated with early menarche (p-trend=0.03), having given birth (p=0.01), and weakly with elevated BMI (p-trend=0.06). After adjustment, increased ovarian volume was associated with higher estradiol (p-trend=0.007); albumin-bound estradiol (p-trend=0.01); and free estradiol (p-trend=0.006) levels; androstenedione, estrone and estrone sulfate showed similar, though non-significant associations.

CONCLUSIONS

Among women with endometrial carcinoma, larger ovaries were associated with higher serum levels of estrogens. Further studies examining the role of the ovaries in post-menopausal hormonal carcinogenesis are warranted.

Does androgen excess contribute to the cardiovascular risk profile in postmenopausal women with type 2 diabetes?

The purpose of this study was to determine if postmenopausal women with type 2 diabetes have clinical and biochemical evidence of androgen excess as a potential contributor to an increase in risk for coronary heart disease when compared with women without diabetes. Fasting glucose, insulin, lipids, sex hormone-binding globulin (SHBG), and sex steroids (from pooled samples) (total testosterone and free testosterone [non-SHBG-T], androstenedione [A-dione], total estrogens) were measured at baseline in 16 postmenopausal women with type 2 diabetes treated with diet or a sulfonylurea and 17 age-matched controls. Measurements of glucose, insulin, and sex steroids were repeated at hourly intervals for 3 hours after oral glucose administration. Hirsutism scores and insulin sensitivity (homeotasis model assessment [HOMA] insulin [SI]) were obtained. Women with type 2 diabetes were more hyperglycemic, hyperinsulinemic, and insulin-resistant (HOMA SI, 46.7 +/- 7.0 vs 12.9 +/- 2.0, P < .001), and had higher total to high-density lipoprotein cholesterol (TC/HDL) ratios, lower SHBG (20.8 +/- 3.5 vs 59.3 +/- 14.4 nmol/L, P < .05), higher non-SHBG-T (0.225 +/- 0.025 vs 0.135 +/- 0.021 nmol/L, P < .05), and higher hirsutism scores (1.1 +/- 0.3 vs 0.3 +/- 0.2, P = .004) than those without diabetes. No changes in sex steroids occurred after the oral glucose challenge. HOMA SI and area under the curve for glucose correlated significantly with SHBG (r = -0.42), non-SHBG-T (r = 0.40), and TC/HDL (r = 0.41) (all P < .05) in the combined groups. Postmenopausal women with type 2 diabetes have both clinical and biochemical evidence of androgen excess that may contribute to more adverse cardiovascular risk profiles.

Testosterone supplementation in aging men and women: possible impact on cardiovascular-renal disease

Treatment of aging men and women with testosterone supplements is increasing. The supplements are given to postmenopausal women mainly to improve their libido and to aging men to improve muscle mass and bone strength, to improve libido and quality of life, to prevent and treat osteoporosis, and, with the phosphodiesterase-5 inhibitors, such as sildenafil, to treat erectile dysfunction. The increased use of testosterone supplements in aging individuals has occurred despite the fact that there have been no rigorous clinical trials examining the effects of chronic testosterone on the cardiovascular-renal disease risk. Studies in humans and animals have suggested that androgens can increase blood pressure and compromise renal function. Androgens have been shown to increase tubular sodium and water reabsorption and activate various vasoconstrictor systems in the kidney, such as the renin-angiotensin system and endothelin. There is also evidence that androgens may increase oxidative stress. Furthermore, the kidney contains the enzymes necessary to produce androgens de novo. This review presents an overview of the data from human and animal studies in which the role of androgens in promoting renal and cardiovascular diseases has been investigated.

Is aromatase cytochrome P450 involved in the pathogenesis of endometrioid endometrial cancer?

Prospectively, the relationship between androgen levels in the utero-ovarian circulation, aromatase activity in endometrial and body fat tissue, and the presence or absence of endometrioid endometrial cancer was studied in postmenopausal women. In 43 women with endometrioid endometrial cancer and 8 women with a benign gynecological condition, a hysterectomy with bilateral salpingo-oophorectomy was performed. Using tritium water-release assays, aromatase activities in endometrial and body fat tissue were determined and related to the steroid levels from the peripheral and the utero-ovarian venous circulation (estradiol, androstenedione, testosterone) and to the presence or absence of endometrial cancer. Significant aromatase activity was found in both benign and malignant endometrial tissue samples. Aromatase activity in samples of endometrial tissue and in samples of body fat did not correlate with steroid levels in peripheral or utero-ovarian venous blood. Aromatase activity in samples of benign or malignant endometrium did not differ. Remarkably, in four women with mainly poorly differentiated endometrial cancer, very high aromatase activity was found in endometrial tissue. It is likely that multiple pathogenetic pathways exist that eventually lead to the formation of endometrioid endometrial cancer. The local availability of androgens and the finding that aromatase activity is present in both endometrial cancer and benign endometrial tissue support the hypothesis that aromatase activity in the endometrium may play a role in malignant transformation by converting androgens into mitogenic estrogens in the endometrial tissue.

Aromatase Expression in Stromal Cells of Endometrioid Endometrial Cancer Correlates with Poor Survival

PURPOSE AND EXPERIMENTAL DESIGN

To assess the prognostic significance of intratumoral aromatase in endometrioid endometrial cancer, sections from 55 patients with endometrial cancer were evaluated for expression of aromatase using immunohistochemistry, and the correlation between aromatase expression and clinicopathologic parameters were analyzed.

RESULTS

Immunohistochemical staining for aromatase was positive for 32 (58%), 20 (36%), and 19 (34%) patients in cancer epithelial cells, stromal cells, and myometrial cells around the flank invasion, respectively. In situ hybridization also detected aromatase mRNA in all three types of cells. RT-PCR analysis revealed that aromatase mRNA was 2.5 +/- 1.0 amol/mug total RNA (mean +/- SE; n = 7) in tumor tissue. Western blot analysis detected the expected aromatase protein size of 58 kDa in cancer tissues more abundantly than in cancer-free endometrium (n = 3). The immunoreactivity in stromal cells correlated positively with advanced surgical stage and poor survival. Survival analysis revealed that the immunoreactivity of stromal cells was a significant prognostic factor, independent of histologic grade, muscular invasion, and lymph node metastasis, but dependent on surgical stage. By contrast, the immunoreactivity of aromatase both in cancer epithelial cells and myometrial cells did not correlate with prognosis.

CONCLUSIONS

To the best of our knowledge, this is the first evidence associating intratumoral aromatase expression in stromal cells and poor survival in endometrioid endometrial cancer. This positive linkage indicates that local expression of aromatase plays a role in tumor progression through the formation of in situ estrogens. In situ expression of aromatase may offer a potential target for management of endometrial cancers.

Novel mechanisms responsible for postmenopausal hypertension

Blood pressure increases in many women after menopause. Hypertension is one of the major risk factors for cardiovascular disease. However, the mechanisms responsible for the postmenopausal increase in blood pressure are yet to be elucidated. Various humoral systems have been proposed to play a role in postmenopausal hypertension, such as changes in estrogen/androgen ratios, increases in endothelin and oxidative stress, and activation of the renin-angiotensin system (RAS). In addition, obesity, type II diabetes, and activation of the sympathetic nervous system are common in postmenopausal women and may also play important roles. However, progress in elucidating the mechanisms responsible for postmenopausal hypertension has been hampered by the lack of a suitable animal model. The aging female spontaneously hypertensive rat (SHR) exhibits many of the characteristics found in postmenopausal women. In this review, some of the possible mechanisms that could play a role in postmenopausal hypertension are discussed, as well as the characteristics of the aged female SHR as a model to study.

The follicle-deplete mouse ovary produces androgen

The follicle-depleted postmenopausal ovary is enriched in interstitial cells that produce androgens. This study was designed to cause follicle depletion in mice using the industrial chemical, 4-vinylcyclohexene diepoxide (VCD), and characterize the steroidogenic capacity of cells in the residual ovarian tissue. From a dose-finding study, the optimal daily concentration of VCD was determined to be 160 mg/kg. Female B6C3F(1) immature mice were treated daily with vehicle control or VCD (160 mg kg(-1) day(-1), 15 days, i.p.). Ovaries were removed and processed for histological evaluation. On Day 15 following onset of treatment, primordial follicles were depleted and primary follicles were reduced to about 10% of controls. On Day 46, primary follicles were depleted and secondary and antral follicles were reduced to 0.7% and 2.6% of control, respectively. Seventy-five percent of treated mice displayed disruptions in estrous cyclicity. All treated mice were in persistent diestrus (acyclic) by Day 58. Plasma FSH levels were increased (P < 0.05) relative to controls on Day 37 and had plateaued by Day 100. Relative to age-matched cyclic controls, by Day 127, the significant differences in VCD-treated mice included reduced ovarian and uterine weights, elevated plasma LH and FSH, and reduced plasma progesterone and androstenedione. Furthermore, plasma 17beta-estradiol levels were nondetectable. Unlike controls, immunostaining for LH receptor, and the high density lipoprotein receptor (SR-BI), was diffuse in ovarian sections from VCD-treated animals. Ovaries from Day 120 control and VCD-treated animals were dissociated and dispersed cells were placed in culture. Cultured cells from ovaries of VCD-treated animals produced less LH-stimulated progesterone than control cells. Androstenedione production was nondetectable in cells from cyclic control animals. Conversely, cells from VCD-treated animals produced androstenedione that was doubled in the presence of insulin and LH (1 and 3 ng/ml). Collectively, these data demonstrate that VCD-mediated follicle depletion results in residual ovarian tissue that may be analogous to the follicle-deplete postmenopausal ovary. This may serve as a useful animal model to examine the dynamics of follicle loss in women as ovarian senescence ensues.

A technique for transplantation of ovarian cortical strips to the forearm

OBJECTIVE

To describe a forearm heterotopic ovarian transplantation technique.

DESIGN

Case study.

SETTING

Academic medical center.

PATIENT(S)

One patient with stage IIIB squamous cell cervical carcinoma and one patient with recurrent benign ovarian cysts.

INTERVENTION(S)

Preparation of thin ovarian cortical slices and transplantation under the skin of the forearm.

MAIN OUTCOME MEASURE(S)

Follicular development and oocyte retrieval; cyclical estradiol (E(2)) and progesterone (P(4)) production; restoration of serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels to reproductive age range.

RESULT(S)

Both patients were menopausal immediately after oophorectomy. The first patient developed a dominant follicle 10 weeks after transplantation, and her gonadotropin levels decreased to nonmenopausal levels. Percutaneous aspiration of ovarian follicles yielded a metaphase I (M-I) oocyte that was matured to metaphase II (M-II). The first patient's graft was functional for at least 21 months. In the second patient, ovarian follicle development was detected 6 months after transplantation, and periodic menstruation occurred thereafter. Spontaneous ovulation was confirmed by a midluteal increase in her P(4) levels. Menstruation and follicle development continued for more than 2 years after the transplant.

CONCLUSION(S)

Heterotopic transplantation of ovarian tissue to the forearm is a simple and promising technique to restore ovarian function in women who become menopausal due to chemotherapy, surgery, or radiation.

Estrogen and testosterone have opposing effects on chronic cardiac remodeling and function in mice with myocardial infarction

Premenopausal women are much less prone to develop cardiovascular disease than men of similar age, but this advantage no longer applies after menopause. We previously found that male mice have a significantly higher rate of cardiac rupture than females during the acute phase of myocardial infarction (MI); however, the effects of sexual hormones on chronic remodeling are unknown. We hypothesized that estrogen (E) may protect the heart from chronic remodeling and deterioration of function post-MI, whereas testosterone (T) may have adverse effects. Mice (4 wk old) of both genders were divided into four groups: female groups consisted of 1) sham ovariectomy (S-Ovx) + placebo (P) (S-Ovx + P), 2) S-Ovx + T, 3) Ovx + P, and 4) Ovx + T; and male groups consisted of 1) sham castration (S-Cas)+ P (S-Cas + P), 2) S-Cas + 17beta-estradiol (E), 3) Cas + P, and 4) Cas + E. MI was induced 6 wk later. Echocardiography was performed to assess cardiac function and left ventricular dimensions (LVD). Myocyte cross-sectional area (MCSA) was measured at the end of the study. In females, both testosterone and ovariectomy decreased ejection fraction (EF) and increased LVD, and when combined they aggravated cardiac function and remodeling further. Testosterone significantly increased MCSA. In males, castration or estrogen increased EF and reduced LVD, whereas castration significantly reduced MCSA. Our data suggest that estrogen prevents deterioration of cardiac function and remodeling after MI, but testosterone worsens cardiac dysfunction and remodeling and has a pronounced effect when estrogen levels are reduced.

The postmenopausal ovary as an androgen-producing gland; hypothesis on the etiology of endometrial cancer

Postmenopausal estrogens originate from the peripheral conversion of androgens, which are produced by the adrenal glands and the ovaries. Estrogens are considered to contribute to the neoplastic development of endometrium. Hyperplasia of ovarian stroma is associated with an increased androgen production by the ovaries and with the development of endometrial pathology. We hypothesize that, in cases of endometrial pathology, an increased production of aromatizable androgens by postmenopausal ovaries will lead to elevated prehormone availability for estrogen formation in utero. Following the conversion of ovarian androgens, a reaction catalyzed by the cytochrome p450 aromatase, estrogens may function as a local mitogenic factor eventually leading to the development of endometrial cancer. We consider the local availability of androgens and the local activity of aromatase relevant for this process. If this hypothesis proves to be right it may give rise to the introduction of aromatase inhibitors in treatment strategies of hormone dependent endometrial malignancies.

Three-dimensional microanatomical dynamics of the ovary in postreproductive aged women

OBJECTIVE

To evaluate the microanatomical dynamics of the ovary during postreproductive life.

DESIGN

Retrospective, observational research study.

SETTING

Institutional (university).

PATIENT(S)

Eleven (43- to 72-year-old) women in perimenopause, menopause, or postmenopause.

INTERVENTION(S)

Biopsies of ovaries obtained from patients undergoing gynecologic surgery or diagnostic procedures.

MAIN OUTCOME MEASURE(S)

Analysis of the 3-dimensional microanatomy of the ovary by transmission and high-resolution scanning electron microscopy.

RESULT(S)

The surface epithelium gets gradually flatter and is always present, even in advanced age. The surface appears smoother because of a smaller number of papillae and crypts as well as a decreased number and shortening of microvilli on surface epithelial cells. Signs of atrophy and fibrosis are evident. Primordial follicles are usually absent in postmenopause, whereas corpora atretica, hemorrhagica, and albicantia, scar tissue, and simple follicular cysts are common after menopause. Apoptotic and necrotic cells appear frequently within the surface epithelium. Major common features are a marked reduction in number and caliber of blood vessels with thickening of the vascular walls and changes in endothelial cells.

CONCLUSION(S)

Scanning electron microscopy studies are a useful complement to ordinary gynecologic diagnostic methods. Variations among patients of the same age range or functional status should be considered.

Ovarian ageing and the menopausal transition

The underlying cause of the menopausal transition is a dwindling supply of FSH-responsive follicles available for ovulation. Additional factors may include dysregulation of existing follicles and concurrent follicle and oocyte deficits that may be strictly anatomic or consequences of the hormonal milieu. In the early transition, menstrual irregularity is infrequent but cycle length shortens by 1-4 days. Oestrogen production may be overall elevated, even in ovulatory cycles. As anovulatory cycles become more common, and amenorrhoea of greater duration, evidence of impaired hypothalamic-pituitary function is present. Oestradiol has been implicated as an agent responsible for the impaired positive feedback response. A model of the early menopausal transition suggests that the loss of FSH restraint by the inhibins, due to a critically diminished follicle pool, is the early event that precedes overt follicle failure and may initiate intervals of hyperoestrogenaemia. The hormonal fluctuations in the early and late menopausal transition may account for some of the signs and symptoms seen during these phases.

Decreased free testosterone and dehydroepiandrosterone-sulfate (DHEA-S) levels in women with decreased libido

A prior study has shown that premenopausal women could have decreased testosterone levels and still have regular menstrual cycles (Guay, 2001). Since ovarian function in such women was normal, the question of a possible adrenal dysfunction causing androgen deficiency was considered. If this was true, the question then arose as to whether the same defect could be seen in postmenopausal women. We studied 105 women who presented during a 6-month period of time with the chief complaint of decreased sexual desire. On subsequent testing, 74 of the women (70%) were found to have decreased total testosterone, free testosterone, and dehydroepiandrosterone sulfate (DHEA-S). Thirty-six of these women were premenopausal (ages range 24-50 years), and 38 were postmenopausal (ages range 47-78 years). All androgen levels for the women were lower than age-matched control groups found in the literature. The decreased DHEA-S levels suggest a a defect in adrenal steroidogenesis, which was seen in both premenopausal and postmenopausal women. Possible defects in regulatory mechanisms of adrenal steroidogenesis are discussed.

Gender differences in the regulation of blood pressure

Men are at greater risk for cardiovascular and renal disease than are age-matched, premenopausal women. Recent studies using the technique of 24-hour ambulatory blood pressure monitoring have shown that blood pressure is higher in men than in women at similar ages. After menopause, however, blood pressure increases in women to levels even higher than in men. Hormone replacement therapy in most cases does not significantly reduce blood pressure in postmenopausal women, suggesting that the loss of estrogens may not be the only component involved in the higher blood pressure in women after menopause. In contrast, androgens may decrease only slightly, if at all, in postmenopausal women. In this review the possible mechanisms by which androgens may increase blood pressure are discussed. Findings in animal studies show that there is a blunting of the pressure-natriuresis relationship in male spontaneously hypertensive rats and in ovariectomized female spontaneously hypertensive rats treated chronically with testosterone. The key factor in controlling the pressure-natriuresis relationship is the renin-angiotensin system (RAS). The possibility that androgens increase blood pressure via the RAS is explored, and the possibility that the RAS also promotes oxidative stress leading to production of vasoconstrictor substances and reduction in nitric oxide availability is proposed.