Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies

Differences in coronary angiographic findings and outcomes between men and postmenopausal women with stable chest pain

BACKGROUND

Despite the significant increase in cardiovascular events in women after menopause, studies comparing postmenopausal women and men are scarce.

METHODS

We analyzed data from a nationwide, multicenter, prospective registry and enrolled 2412 patients with stable chest pain who underwent elective coronary angiography. Binary coronary artery disease (b-CAD) was defined as the ≥50% stenosis of epicardial coronary arteries, including the left main coronary artery.

RESULTS

Compared with the men, postmenopausal women were older (66.6 ± 8.5 vs. 59.5 ± 11.4 years) and had higher high-density lipoprotein cholesterol levels (49.0 ± 12.8 vs. 43.6 ± 11.6 mg/dl, P  < 0.01). The prevalence of diabetes did not differ significantly ( P  = 0.40), and smoking was more common in men than in postmenopausal women ( P  ≤ 0.01). At enrollment, b-CAD and revascularization were more common in men than in postmenopausal women (50.3% vs. 41.0% and 14.4% vs. 9.7%, respectively; both P  < 0.01). However, multivariate analyses revealed that revascularization [odds ratio (OR): 0.72; 95% confidence interval (CI): 0.49-1.08] was not significantly related to sex and a similar result was found in age propensity-matched population (OR: 0.80; 95% CI: 0.52-1.24). During the follow-up period, the secondary composite cardiovascular outcomes were lower in postmenopausal women than in men (OR: 0.55; 95% CI: 0.31-0.98), also consistent with the result using the age propensity-mated population (OR: 0.33; 95% CI: 0.13-0.85).

CONCLUSION

Postmenopausal women experienced coronary revascularization comparable to those in men at enrollment, despite the average age of postmenopausal women was 7 years older than that of men.Postmenopausal women exhibit better clinical outcomes than those of men if optimal treatment is provided.

Estro G-100 herbal extract and hot flashes in postmenopausal women: A randomized double-blinded controlled trial

OBJECTIVE

The present study aimed to determine the efficacy of EstroG-100 herbal extract on hot flashes in postmenopausal women.

MATERIAL AND METHODS

This randomized, double-blind, placebo-controlled trial was performed on postmenopausal women recruited from two university hospitals complaining of hot flashes. The intervention group received two extract capsules (daily for 12 weeks), and the control group received two placebo capsules (daily for 12 weeks). Finally, the frequency and severity of hot flashes (F&S) were subjectively reported and compared weekly during the treatment for 12 weeks.

RESULTS

Out of 120 randomized participants, 35 entered the final analysis for each group. In the third week, participants of the control group significantly reported more moderate hot flashes than other group (MD=1.00, P = 0.004). However, in terms of mild (MD=0.74, P = 0.057) and severe (MD=0.60, P = 0.064) hot flashes, the groups did not differ. In the sixth week, mild (MD=1.51, P<0.001), moderate (MD=1.54, P<0.001), and severe (MD=1.22, P<0.001) hot flashes were significantly reported more in the control group compared with another group.

CONCLUSION

The present study revealed that EstroG-100 herbal extract could improve hot flashes in postmenopausal women.

Lifetime cumulative effect of reproductive factors on ischaemic heart disease in a prospective cohort

OBJECTIVE

This study aimed to examine the association between lifetime oestrogen exposure and ischaemic heart disease (IHD), based on the hypothesis that higher lifetime oestrogen exposure is linked to lower cardiovascular risk.

METHODS

In 2004-2008, lifetime cumulative exposure to reproductive factors was assessed among postmenopausal females from the China Kadoorie Biobank using reproductive lifespan (RLS), endogenous oestrogen exposure (EEE) and total oestrogen exposure (TEE). EEE was calculated by subtracting pregnancy-related and contraceptive use duration from RLS, while TEE by adding up the same components except for lactation. Incident IHD during follow-up (2004-2015) was identified. Stratified Cox proportional hazards models estimated the HRs and 95% CIs of IHD for RLS, EEE and TEE.

RESULTS

Among 118 855 postmenopausal females, 13 162 (11.1%) developed IHD during a median follow-up of 8.9 years. The IHD incidence rates were 13.0, 12.1, 12.5, 13.8 per 1000 person-years for RLS Q1-Q4, 15.8, 12.6, 11.3, 12.1 per 1000 person-years for EEE Q1-Q4 and 13.7, 12.3, 12.2, 13.4 per 1000 person-years for TEE Q1-Q4. The highest quartile (Q4) of RLS and TEE were associated with lower risks of IHD (adjusted HR (aHR) 0.95, 95% CI 0.91 to 1.00 and 0.92, 95% CI 0.88 to 0.97, respectively) compared with the lowest quartile (Q1). Longer EEE showed progressively lower risks of incident IHD (aHR 0.93, 95% CI 0.88 to 0.97; 0.88, 95% CI 0.84 to 0.93; 0.87, 95% CI 0.83 to 0.92 for Q2-Q4 vs Q1).

CONCLUSIONS

Longer RLS, TEE and EEE were associated with lower risks of IHD among Chinese postmenopausal females.

Aversion-associated drug and alcohol seeking in females

Compulsive drug intake is characterized by the continuation of use regardless of negative consequences. This is modeled preclinically using procedures where a negative stimulus is delivered contingently with consumption of the reinforcer. In humans, women and men exhibit different drug taking behavior as it pertains to overall use, withdrawal symptoms, and rate of dependence. In substance use research, females have often been excluded from many studies due to concerns that circulating sex hormones may affect drug seeking behavior. However, the more recent inclusion of females in preclinical studies has identified interesting sex differences in aversion-resistant intake of drugs and alcohol. This review will serve to summarize key findings in aversion-related intake of alcohol, psychostimulants, and opioids in females by examining studies that have included female subjects. Further discussion will examine the effect of intake model, neuroanatomical pathways, and sex hormones in the expression of aversion-resistant drug and alcohol consumption.

Gender-based research underscores sex differences in biological processes, clinical disorders and pharmacological interventions

Earlier research has presumed that the male and female biology is similar in most organs except the reproductive system, leading to major misconceptions in research interpretations and clinical implications, with serious disorders being overlooked or misdiagnosed. Careful research has now identified sex differences in the cardiovascular, renal, endocrine, gastrointestinal, immune, nervous, and musculoskeletal systems. Also, several cardiovascular, immunological, and neurological disorders have shown differences in prevalence and severity between males and females. Genetic variations in the sex chromosomes have been implicated in several disorders at young age and before puberty. The levels of the gonadal hormones estrogen, progesterone and testosterone and their receptors play a role in the sex differences between adult males and premenopausal women. Hormonal deficiencies and cell senescence have been implicated in differences between postmenopausal and premenopausal women. Specifically, cardiovascular disorders are more common in adult men vs premenopausal women, but the trend is reversed with age with the incidence being greater in postmenopausal women than age-matched men. Gender-specific disorders in females such as polycystic ovary syndrome, hypertension-in-pregnancy and gestational diabetes have attained further research recognition. Other gender-related research areas include menopausal hormone therapy, the "Estrogen Paradox" in pulmonary arterial hypertension being more predominant but less severe in young females, and how testosterone may cause deleterious effects in the kidney while having vasodilator effects in the coronary circulation. This has prompted the National Institutes of Health (NIH) initiative to consider sex as a biological variable in research. The NIH and other funding agencies have provided resources to establish state-of-the-art centers for women health and sex differences in biology and disease in several academic institutions. Scientific societies and journals have taken similar steps to organize specialized conferences and publish special issues on gender-based research. These combined efforts should promote research to enhance our understanding of the sex differences in biological systems beyond just the reproductive system, and provide better guidance and pharmacological tools for the management of various clinical disorders in a gender-specific manner.

Hormonal contraceptive exposure relates to changes in resting state functional connectivity of anterior cingulate cortex and amygdala

Introduction

Hormonal contraceptives (HCs), nowadays one of the most used contraceptive methods, downregulate endogenous ovarian hormones, which have multiple plastic effects in the adult brain. HCs usually contain a synthetic estrogen, ethinyl-estradiol, and a synthetic progestin, which can be classified as androgenic or anti-androgenic, depending on their interaction with androgen receptors. Both the anterior cingulate cortex (ACC) and the amygdala express steroid receptors and have shown differential functionality depending on the hormonal status of the participant and the use of HC. In this work, we investigated for the first time the relationship between ACC and amygdala resting state functional connectivity (rs-FC) and HC use duration, while controlling for progestin androgenicity.

Methods

A total of 231 healthy young women participated in five different magnetic resonance imaging studies and were included in the final analysis. The relation between HC use duration and (i) gray matter volume, (ii) fractional amplitude of low-frequency fluctuations, and (iii) seed-based connectivity during resting state in the amygdalae and ACC was investigated in this large sample of women.

Results

In general, rs-FC of the amygdalae with frontal areas, and between the ACC and temporoparietal areas, decreased the longer the HC exposure and independently of the progestin's androgenicity. The type of HC's progestin did show a differential effect in the gray matter volume of left ACC and the connectivity between bilateral ACC and the right inferior frontal gyrus.

The Effect of Ramadan Intermittent Fasting on Food Intake, Anthropometric Indices, and Metabolic Markers among Premenopausal and Postmenopausal Women: A Cross-Sectional Study

Background and objectives: Ramadan intermittent fasting (RIF) is a monthlong practice in which Muslims fast during the whole day from sunrise to sunset. During this month, fasting people change their dietary behavior and alter their eating hours from day to night. The objective of the current study was to examine the effect of RIF on dietary consumption, anthropometric indices, and metabolic markers in healthy premenopausal (PRE-M) and postmenopausal (POST-M) Saudi women. Materials and Methods: The study included 62 women (31 PRE-M, 21-42 years, and 31 POST-M, 43-68 years). A structured questionnaire was used to collect socioeconomic data. Physical activity, anthropometric, dietary, and biochemical assessments were assessed before and at the end of the third week of Ramadan. Results: Socioeconomic data varied among participants. For both groups, observing RIF was associated with significantly (at either p ≤ 0.01 or p ≤ 0.05) lower intake of calories, macronutrients, minerals (excluding Na), and vitamins than before RIF. For the PRE-M group, the percentage of overweight participants decreased significantly (p ≤ 0.01) during Ramadan, while the percentage of obese participants remained unchanged. In contrast, for the POST-M group, the percentage of overweight participants increased significantly (p ≤ 0.05) during Ramadan, but dropped at the end of Ramadan. Following RIF, waist-to-hip ratio, body fat, and fat mass (FM) decreased in both groups. High-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), triglycerides (TG), and blood pressure (SBP, DBP) were generally maintained at acceptable normal levels in most participants before and at the end of RIF. However, low-density lipoprotein cholesterol (LDL-C) at the end of RIF was significantly lower than before, particularly in POST-M women. Age, occupation, and monthly income were the most important predictors for the changes in nutritional status and body fat upon RIF. Conclusions: observing RIF by PRE-M and POST-M Saudi women was associated with significant improvements in variable health indicators, with a few exceptions, and may help lower risk factors for chronic diseases, particularly among POST-M women. However, further studies with a larger sample size are required to determine and confirm the exact effect of RIF on these groups.

Hormone-based models for comparing menstrual cycle and hormonal contraceptive effects on human resting-state functional connectivity

Oral contraceptives (OCs) are widely used yet understudied given their potential for public health consequences. Emerging investigations scaling from single-subject, dense-sampling neuroimaging studies to population-level metrics have linked OCs to altered brain structure and function. Modeling the hypogonadal, hypergonadal, or mixed state effects of OCs in terms of their impact on hormone action in the brain is a valuable approach to synthesizing results across neuroimaging studies and comparing OC effects to companion findings from research on menstrual cycle phase effects on brain anatomy and function. Resting-state functional connectivity studies provide a powerful tool to evaluate the role of OCs on the intrinsic network connectivity that underlies multiple behavioral domains. The preponderance (but not consensus) of the current literature indicates that (1) as the menstrual cycle proceeds from a low to high progesterone state, prefrontal connectivity increases and parietal connectivity decreases; (2) OCs tend to mimic this connectivity pattern; therefore (3) OCs may produce a hyperprogestogenic state in the brain, in spite of overall reductions in endogenous steroid hormone levels. Alternative models are also considered.

Shared Genetics Between Age at Menopause, Early Menopause, POI and Other Traits

Reproductive ageing leading to menopause is characterized by depletion of follicles and its regulating mechanisms are only partly understood. Early age at menopause and premature ovarian insufficiency (POI) are associated with several other traits such as cardiovascular disease, dyslipidemia, osteoporosis and diabetes. In large cohorts of Northern European women hundreds of Single Nucleotide Polymorphisms (SNPs) have been identified to be associated with age at menopause. These SNPs are located in genes enriched for immune and mitochondrial function as well as DNA repair and maintenance processes. Genetic predisposition to earlier menopause might also increase the risk of other associated traits. Increased risk for cardiovascular disease in women has been associated with age at menopause lowering SNPs. Pleiotropy between early age at menopause and increased mortality from coronary artery disease has been observed, implicating that genetic variants affecting age at menopause also affect the risk for coronary deaths. This review will discuss the shared genetics of age at menopause with other traits. Mendelian Randomization studies implicate causal genetic association between age at menopause and age at menarche, breast cancer, ovarian cancer, BMD and type 2 diabetes. Although the shared biological pathways remain to be determined, mechanisms that regulate duration of estrogen exposure remain an important focus.

Position statement on the diagnosis and management of premature/primary ovarian insufficiency (except Turner Syndrome)

Premature ovarian insufficiency (POI) is a rare pathology affecting 1-2% of under-40 year-old women, 1 in 1000 under-30 year-olds and 1 in 10,000 under-20 year-olds. There are multiple etiologies, which can be classified as primary (chromosomal, genetic, auto-immune) and secondary or iatrogenic (surgical, or secondary to chemotherapy and/or radiotherapy). Despite important progress in genetics, more than 60% of cases of primary POI still have no identifiable etiology; these cases are known as idiopathic POI. POI is defined by the association of 1 clinical and 1 biological criterion: primary or secondary amenorrhea or spaniomenorrhea of>4 months with onset before 40 year of age, and elevated follicle-stimulating hormone (FSH)>25IU/L on 2 assays at>4 weeks' interval. Estradiol level is low, and anti-Müllerian hormone (AMH) levels have usually collapsed. Initial etiological work-up comprises auto-immune assessment, karyotype, FMR1 premutation screening and gene-panel study. If all of these are normal, the patient and parents may be offered genome-wide analysis under the "France Génomique" project. The term ovarian insufficiency suggests that the dysfunction is not necessarily definitive. In some cases, ovarian function may fluctuate, and spontaneous pregnancy is possible in around 6% of cases. In confirmed POI, hormone replacement therapy is to be recommended at least up to the physiological menopause age of 51 years. Management in a rare diseases center may be proposed.

Protein disulfide isomerase A3 might be involved in the regulation of 24-dehydrocholesterol reductase via vitamin D equilibrium in primary cortical neurons

Vitamin D is a secosteroid hormone mediating its functions via vitamin D receptor (VDR) and an endoplasmic reticulum chaperone, protein disulfide isomerase A3 (PDIA3). From a physiological perspective, there is also a well-established association of cholesterol and vitamin D synthesis, since both share a common metabolic substrate, 7 dehydrocholesterol (7-DHC). Yet, the potential basic pathways, of the biological interplay of DHCR24 and vitamin D equilibrium, on neuronal level, are yet to be determined. In this study, we aimed to investigate the relation between vitamin D pathways and DHCR24 in primary cortical neuron cultures. The neocortex of Sprague-Dawley rat embryos (E16) was used for the preparation of primary cortical neuron cultures. DHCR24 mRNA and protein expression levels were determined by qRT-PCR, Western blotting, and immunofluorescent labeling in 1,25-dihydroxyvitamin D3-treated or VDR/PDIA3-silenced primary cortical neurons. The mRNA expression of DHCR24 was significantly decreased in the cortical neurons treated with 10-8M 1,25-dihydroxyvitamin D3 (p<0.001). In parallel with the mRNA results, DHCR24 protein expression in cortical neurons treated with 10-8M 1,25-dihydroxyvitamin D3 was also significantly lower than untreated neurons (p<0.05). These data were also confirmed with immunofluorescent labeling and fluorescence intensity measurements of DHCR24 (p<0.001). Finally, DHCR24 mRNA expression level was significantly increased in PDIA3 siRNA-treated neurons (p<0.05). Similar to the mRNA results, the DHCR24 protein expression of PDIA3 siRNA-treated neurons was also statistically higher than the other groups (p<0.05). Results of this mechanistic experimental basic study demonstrate that DHCR24 mRNA expression and protein concentrations attenuated in response to vitamin D treatment. Furthermore, we observed that PDIA3 might be involved in this modulatory effect. Our findings indicate a complex interaction of DHCR24 and vitamin D equilibrium, through the involvement of PDIA3 and vitamin D in the modulation of cholesterol metabolism in neuronal cells, requiring future studies on the field.

Oestrogen treatment modulates the impact of cognitive experience and task complexity on memory in middle-aged surgically menopausal rats

Menopause has been linked to changes in memory. Oestrogen-containing hormone therapy is prescribed to treat menopause-related symptoms and can ameliorate memory changes, although the parameters impacting oestrogen-related memory efficacy are unclear. Cognitive experience and practice have been shown to be neuroprotective and to improve learning and memory during ageing, with the type of task playing a role in subsequent cognitive outcomes. Whether task complexity matters, and whether these outcomes interact with menopause and oestrogen status, remains unknown. To investigate this, we used a rat model of surgical menopause to systematically assess whether maze task complexity, as well as order of task presentation, impacts spatial learning and memory during middle age when rats received vehicle, low-17β-oestradiol (E2 ) or high-E2 treatment. The direction, and even presence, of the effects of prior maze experience differed depending on the E2 dose. Surgical menopause without E2 treatment yielded the least benefit, as prior maze experience did not have a substantial effect on subsequent task performance for vehicle treated rats regardless of task demand level during the first exposure to maze experience or final testing. High-dose E2 yielded a variable benefit, and low-dose E2 produced the greatest benefit. Specifically, low-dose E2 broadly enhanced learning and memory in surgically menopausal rats that had prior experience on another task, regardless of the complexity level of this prior experience. These results demonstrate that E2 dose influences the impact of prior cognitive experience on learning and memory during ageing, and highlights the importance of prior cognitive experience in subsequent learning and memory outcomes.

17-β Estradiol Rescued Immature Rat Brain against Glutamate-Induced Oxidative Stress and Neurodegeneration via Regulating Nrf2/HO-1 and MAP-Kinase Signaling Pathway

Dysregulated glutamate signaling, leading to neuronal excitotoxicity and death, has been associated with neurodegenerative pathologies. 17β-estradiol (E2) is a human steroid hormone having a role in reproduction, sexual maturation, brain health and biological activities. The study aimed to explain the neuroprotective role of E2 against glutamate-induced ROS production, MAP kinase-dependent neuroinflammation, synaptic dysfunction and neurodegeneration in the cortex and hippocampus of postnatal day 7 rat brain. Biochemical and immunofluorescence analyses were applied. Our results showed that a single subcutaneous injection of glutamate (10 mg/kg) induced brain oxidative stress after 4 h by disturbing the homeostasis of glutathione (GSH) and revealed an upsurge in ROS and LPO levels and downregulated the expression of Nrf2 and HO-1 antioxidant protein. The glutamate-exposed P7 pups illustrated increased phosphorylation of stress-activated c-Jun N-terminal kinase (JNK) and p38 kinase (p38) and downregulated expression of P-Erk1/2. This was accompanied by pathological neuroinflammation as revealed by enhanced gliosis with upregulated expression of GFAP and Iba-1, and the activation of proinflammatory cytokines (TNF-α) in glutamate-injected P7 pups. Moreover, exogenous glutamate also reduced the expression of synaptic markers (PSD-95, SYP) and induced apoptotic neurodegeneration in the cortical and hippocampal regions by dysregulating the expression of Bax, Bcl-2 and caspase-3 in the developing rat brain. On the contrary, co-treatment of E2 (10 mg/kg) with glutamate significantly abrogated brain neuroinflammation, neurodegeneration and synapse loss by alleviating brain oxidative stress by upregulating the Nrf2/HO-1 antioxidant pathway and by deactivating pro-apoptotic P-JNK/P-p38 and activation of pro-survival P-Erk1/2 MAP kinase pathways. In brief, the data demonstrate the neuroprotective role of E2 against glutamate excitotoxicity-induced neurodegeneration. The study also encourages future studies investigating if E2 may be a potent neuroprotective and neurotherapeutic agent in different neurodegenerative diseases.

Cardiovascular health after menopause transition, pregnancy disorders, and other gynaecologic conditions: a consensus document from European cardiologists, gynaecologists, and endocrinologists

Women undergo important changes in sex hormones throughout their lifetime that can impact cardiovascular disease risk. Whereas the traditional cardiovascular risk factors dominate in older age, there are several female-specific risk factors and inflammatory risk variables that influence a woman’s risk at younger and middle age. Hypertensive pregnancy disorders and gestational diabetes are associated with a higher risk in younger women. Menopause transition has an additional adverse effect to ageing that may demand specific attention to ensure optimal cardiovascular risk profile and quality of life. In this position paper, we provide an update of gynaecological and obstetric conditions that interact with cardiovascular risk in women. Practice points for clinical use are given according to the latest standards from various related disciplines (Figure 1).

Gender associated disparities in atrioventricular nodal reentrant tachycardia: A review article

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common sustained supraventricular arrhythmias. An understanding of gender-related differences in AVNRT epidemiology, diagnosis, treatment, outcome, and complications can help guide a more effective diagnosis and treatment of the condition. The study aimed to perform a review of the available literature regarding all aspects of gender-related differences of AVNRT. We focused on all aspects of gender-related differences regarding AVNRT between men and women. A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct. Many investigations have demonstrated that the prevalence of AVNRT exhibited a twofold women-to-men predominance. The potential mechanism behind this difference due to sex hormones and autonomic tone. Despite being more common in women, there is a delay in offering and performing the first-line therapy (catheter ablation) compared to men. There were no significant gender-related discrepancies in patients who underwent ablation therapy for AVNRT, regarding the acute success rate of the procedure, long-term success rate, and recurrence of AVNRT. AVNRT is more common in women due to physiological factors such as sex hormones and autonomic tone. Catheter ablation is equally safe and efficacious in men and women; however, the time between the onset of symptoms and ablation is significantly prolonged in women. It is important for the medical community to be aware of this discrepancy and to strive to eliminate such disparities that are not related to patients' choices.

Construction of reporter gene assays using CWP and PDR mutant yeasts for enhanced detection of various sex steroids

Background

Sex steroid hormone receptors are classified into three classes of receptors: estrogen receptors (ER) α and β, androgen receptor (AR), and progesterone receptor (PR). They belong to the nuclear receptor superfamily and activate their downstream genes in a ligand-dependent manner. Since sex steroid hormones are involved in a wide variety of physiological processes and cancer development, synthetic chemical substances that exhibit sex steroid hormone activities have been applied as pharmaceuticals and consumed in large amounts worldwide. They are potentially hazardous contaminants as endocrine disruptors in the environment because they may induce inappropriate gene expression mediated by sex steroid hormone receptors in vivo.

Results

To develop simple reporter gene assays with enhanced sensitivity for the detection of sex steroid hormones, we newly established mutant yeast strains lacking the CWP and PDR genes encoding cell wall mannoproteins and plasma membrane drug efflux pumps, respectively, and expressing human ERα, ERβ, AR, and PR. Reporter gene assays with mutant yeast strains responded to endogenous and synthetic ligands more strongly than those with wild-type strains. Sex steroid hormone activities in some pharmaceutical oral tablets and human urine were also detectable in these yeast assays.

Conclusions

Yeast reporter gene assay systems for all six steroid hormone receptors, including previously established glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) assay yeasts, are now available. Environmental endocrine disrupters with steroid hormone activity will be qualitatively detectable by simple and easy procedures. The yeast-based reporter gene assay will be valuable as a primary screening tool to detect and evaluate steroid hormone activities in various test samples. Our assay system will strongly support the detection of agonists, antagonists, and inverse agonists of steroid hormone receptors in the field of novel drug discovery and assessments of environmental pollutants.

Higher Insulin Resistance and Adiposity in Postmenopausal Women With Breast Cancer Treated With Aromatase Inhibitors

CONTEXT

Aromatase deficiency causes obesity and insulin resistance in aromatase knockout mice and humans with rare mutations of the aromatase gene (CYP19). Aromatase inhibitors are a commonly prescribed therapy for postmenopausal breast cancer.

OBJECTIVE

We hypothesized that aromatase inhibitors induce obesity and insulin resistance when used in treatment of breast cancer.

DESIGN

Case-control study.

SETTING

University teaching hospital.

PARTICIPANTS

Patients with postmenopausal breast cancer (n = 20) treated with aromatase inhibitors and 20 age-matched control subjects.

MAIN OUTCOME MEASURES

The primary outcome measure was insulin sensitivity index - Matsuda, derived from a 75-g oral glucose tolerance test. Body composition was assessed by dual energy x-ray absorptiometry and biopsy specimens of subcutaneous adipose tissue obtained for assessment of mRNA transcript levels. Data are reported as mean ± SEM (patients receiving inhibitors vs control group, respectively).

RESULTS

Aromatase inhibitor therapy was associated with significantly lower insulin sensitivity (5.15 ± 0.45 vs 6.80 ± 0.64; P = 0.041), higher peak insulin concentration after oral glucose tolerance test (693.4 ± 78.6 vs 527.6 ± 85.5 pmol/L; P = 0.035), greater percentage of body fat (38.4% ± 1.0% vs 34.6% ± 1.3%; P = 0.026), and higher plasma leptin concentration (23.5 ± 2.8 vs 15.5 ± 2.3 ng/mL; P = 0.035).

CONCLUSION

Women who received aromatase inhibitors for postmenopausal breast cancer had greater percentage body fat and insulin resistance compared with control subjects with no history of breast cancer.

Lack of influence of estrogen on myosin phosphorylation and post-tetanic potentiation in muscles from young adult C57BL mice

Estrogen influences myosin phosphorylation and post-tetanic potentiation in murine fast muscle. We tested the hypothesis that this influence is mediated by estrogen effects on skeletal myosin light chain kinase (skMLCK) activity. To this end, extensor digitorum longus muscles from female wildtype and skMLCK-absent (skMLCK^-/-) mice were grouped as follows: ovariectomized with estrogen (E+), ovariectomized without estrogen (E-), sham surgery, and intact baseline. At 8 weeks of age, the ovariectomized groups were ovariectomized followed by implantation of either a 0.1 mg 17β-estradiol (E+) or placebo pellet (E-). Two weeks later, muscles were isolated and suspended in vitro (25° C) for determination of regulatory light chain phosphorylation and post-tetanic potentiation. Regulatory light chain phosphorylation was not different across conditions within either genotype although wildtype values were significantly greater than skMLCK^-/- values. Consistent with this, the potentiation of concentric twitch force was similar between E+ and E- groups within each genotype but wildtype values were greater than skMLCK^-/- values. However, unaltered estradiol levels following ovariectomy, likely due to previously underappreciated confounds of mouse age, development, and growth during estrogen supplementation, prevented direct testing of the hypothesis. Future studies should note the importance of estrous cycles and continuing physiological developments of young adult mice when working with ovarian hormones.

Developmental programming: Changes in mediators of insulin sensitivity in prenatal bisphenol A-treated female sheep

Developmental exposure to endocrine disruptor bisphenol A (BPA) is associated with metabolic defects during adulthood. In sheep, prenatal BPA treatment causes insulin resistance (IR) and adipocyte hypertrophy in the female offspring. To determine if changes in insulin sensitivity mediators (increase in inflammation, oxidative stress, and lipotoxicity and/or decrease in adiponectin) and the intracrine steroidal milieu contributes to these metabolic perturbations, metabolic tissues collected from 21-month-old female offspring born to mothers treated with 0, 0.05, 0.5, or 5 mg/kg/day of BPA were studied. Findings showed prenatal BPA in non-monotonic manner (1) increased oxidative stress; (2) induced lipotoxicity in liver and muscle; and (3) increased aromatase and estrogen receptor expression in visceral adipose tissues. These changes are generally associated with the development of peripheral and tissue level IR and may explain the IR status and adipocyte hypertrophy observed in prenatal BPA-treated female sheep.

Changes in body composition and weight during the menopause transition

BACKGROUND

The relation between the menopause transition (MT) and changes in body composition or weight remains uncertain. We hypothesized that, independent of chronological aging, the MT would have a detrimental influence on body composition.

METHODS

Participants were from the longitudinal Study of Women's Health Across the Nation (SWAN) cohort. We assessed body composition by dual energy x-ray absorptiometry. Multivariable mixed effects regressions fitted piece-wise linear models to repeated measures of outcomes as a function of time before or after the final menstrual period (FMP). Covariates were age at FMP, race, study site, and hormone therapy.

RESULTS

Fat and lean mass increased prior to the MT. At the start of the MT, rate of fat gain doubled, and lean mass declined; gains and losses continued until 2 years after the FMP. After that, the trajectories of fat and lean mass decelerated to zero slope. Weight climbed linearly during premenopause without acceleration at the MT. Its trajectory became flat after the MT.

CONCLUSION

Accelerated gains in fat mass and losses of lean mass are MT-related phenomena. The rate of increase in the sum of fat mass and lean mass does not differ between premenopause and the MT; thus, there is no discernable change in rate of weight gain at the start of the MT.

FUNDING

NIH, Department of Health and Human Services (DHHS), through the National Institute on Aging, National Institute of Nursing Research, and NIH Office of Research on Women's Health (U01NR004061, U01AG012505, U01AG012535, U01AG012531, U01AG012539, U01AG012546, U01AG012553, U01AG012554, and U01AG012495).

Hysterectomy Uniquely Impacts Spatial Memory in a Rat Model: A Role for the Nonpregnant Uterus in Cognitive Processes

Approximately one-third of women experience hysterectomy, or the surgical removal of the uterus, by 60 years of age, with most surgeries occurring prior to the onset of natural menopause. The ovaries are retained in about half of these surgeries, whereas for the other half hysterectomy occurs concurrently with oophorectomy. The dogma is that the nonpregnant uterus is dormant. There have been no preclinical assessments of surgical variations in menopause, including hysterectomy, with and without ovarian conservation, on potential endocrine and cognitive changes. We present a novel rat model of hysterectomy alongside sham, ovariectomy (Ovx), and Ovx-hysterectomy groups to assess effects of surgical menopause variations. Rats without ovaries learned the working memory domain of a complex cognitive task faster than did those with ovaries. Moreover, uterus removal alone had a unique detrimental impact on the ability to handle a high-demand working memory load. The addition of Ovx, that is, Ovx-hysterectomy, prevented this hysterectomy-induced memory deficit. Performance did not differ amongst groups in reference memory-only tasks, suggesting that the working memory domain is particularly sensitive to variations in surgical menopause. Following uterus removal, ovarian histology and estrous cycle monitoring demonstrated that ovaries continued to function, and serum assays indicated altered ovarian hormone and gonadotropin profiles by 2 months after surgery. These results underscore the critical need to further study the contribution of the uterus to the female phenotype, including effects of hysterectomy with and without ovarian conservation, on the trajectory of brain and endocrine aging to decipher the impact of common variations in gynecological surgery in women. Moreover, findings demonstrate that the nonpregnant uterus is not dormant, and indicate that there is an ovarian-uterus-brain system that becomes interrupted when the reproductive tract has been disrupted, leading to alterations in brain functioning.

Effects of Urtica dioica hydro-alcoholic extract on blood serum glucose and lipid profiles of female Wistar rats with long-term estrogen deficiency

In this study, the effects of Urtica dioica hydro-alcoholic extract were investigated on the blood glucose and lipid profiles of female ovariectomized and non-ovariectomized rats. In total, 32 adult female rats were divided into four groups (eight each) including control and ovariectomy groups as well as non-ovariectomy and ovariectomy groups treated with 200 mg kg^-1 of Urtica dioica extract orally in the last five weeks of the study starting from the week 56^th. The duration of the study was 60 weeks. Glucose, serum lipid profiles and pancreatic pathological alterations were determined in these groups at the end of experiment. Serum glucose, triglyceride (TG), very-low-density lipoprotein (VLDL), and TG/high-density lipoprotein (HDL) ratio indicated a significant increase in the healthy female rats under treatment with Urtica dioica extract compared to others. The TG, cholesterol, HDL, low-density lipoprotein (LDL) and VLDL showed a significant increase in menopaused rats compared to others. The interaction of consuming Urtica dioica extract and ovariectomy caused significant decreases in glucose, TG, VLDL, HDL/LDL ratio and TG/HDL ratio. Consumption of Urtica dioica extract by non-menopaused rats damaged the beta cells in Langerhans islets. Results of the present study revealed that the consumption of Urtica dioica extract is not beneficial and has diabetogenic effects in female non-ovariectomized rats compared to ovariectomized ones.

Sleep, Health, and Metabolism in Midlife Women and Menopause: Food for Thought

Sleep and metabolism are essential components of health. Metabolic health depends largely on individual's lifestyle. Disturbances in sleep health, such as changes in sleep patterns that are associated with menopause/reproductive aging and chronologic aging, may have metabolic health consequences. Sleep restriction and age-related changes in sleep and circadian rhythms may influence changes in appetite and reproductive hormones, energy expenditure, and body adiposity. In this article, the authors describe how menopause-related sleep disturbance may affect eating behavior patterns, immunometabolism, immunometabolic dysfunction, and associations between sleep and metabolic outcomes.

Arterial stiffness during controlled ovarian hyperstimulation and early pregnancy in women exposed to assisted reproduction

INTRODUCTION

Female sex hormones have vasorelaxing effects in non-pregnant and pregnant women. We aimed to investigate the effect of controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF), and early pregnancy, on arterial stiffness as assessed by digital pulse wave analysis (DPA), hypothesizing reduced arterial stiffness as an effect of increased estrogen levels.

MATERIAL AND METHODS

A total of 68 women undergoing IVF were examined with DPA before conception and during IVF treatment with COH and embryo transfer (ET), and in gestational week seven in 19 women who became pregnant. Heart rate (HR), mean arterial pressure (MAP) and the DPA variables cardiac ejection elasticity index (EEI), b/a, dicrotic index (DI), d/a and aging index (AI) were measured.

RESULTS

HR was significantly increased at all measuring points (p ≤ 0.003) but MAP only at ET (p 0.007). DPA variables representing large arteries (EEI, b/a) and peripheral arteries (DI, but not d/a), and the global variable AI, indicated increased arterial stiffness at ET compared with baseline (p ≤ 0.035). No DPA variable was significantly changed at pregnancy measurements compared to baseline.

CONCLUSION

During COH for IVF treatment, DPA showed no changes in arterial stiffness during the follicular phase or in early pregnancy, but increased arterial stiffness in central and peripheral arteries in the early luteal phase. The result suggests a hormonal hemodynamic activation counteracting the effects of estrogen.

Reproductive Hormones and Subclinical Cardiovascular Disease in Midlife Women

CONTEXT

Reproductive hormones are important to the pathophysiology of cardiovascular disease (CVD) in women. However, standard estradiol (E2) and testosterone (T) assays lack sensitivity at the levels of postmenopausal women.

OBJECTIVE

Investigate relations of mass spectrometry-assessed estrone (E1), E2, and T and SHBG and subclinical CVD in women.

DESIGN, SETTING, AND PARTICIPANTS

Three hundred and four perimenopausal and postmenopausal women aged 40 to 60 years underwent subclinical CVD measurements. E1, E2, and T were assayed using liquid chromatography-tandem mass spectrometry; free T (FT) was estimated using ensemble allostery models. Regression models were adjusted for CVD risk factors.

MAIN OUTCOME MEASURES

Carotid artery intima media thickness, interadventitial diameter (IAD), and plaque; brachial flow mediated dilation (FMD).

RESULTS

Higher E1 was related to higher FMD [β(SE) = 0.77 (0.37), P = 0.04], indicating better endothelial function. Higher E2 was related to lower IAD [β(SE) = -0.07 (0.02), P = 0.004], indicating less carotid remodeling. Higher SHBG was related to higher FMD [β(SE) = 1.31 (0.40), P = 0.001], yet higher IAD [β(SE) = 0.15 (0.06), P = 0.02] and plaque [OR (95% CI) = 1.84 (1.16 to 2.91), P = 0.009]; FT showed a similar yet inverse pattern of relations as SHBG. Thus, higher SHBG and lower FT were associated with better endothelial function, yet greater carotid remodeling and plaque.

CONCLUSIONS

Endogenous E1 levels were related to endothelial function and E2 to vascular remodeling, suggesting distinct roles of these estrogens. SHBG and FT have complex roles depending on the vessel under study.

Repurposing sex steroids and related drugs as potential treatment for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder for which a greater prevalence and incidence is described in men. This suggests a protective effect of sex hormones in the brain. Therefore, steroids and drugs to treat endocrine conditions could have additional application for PD. Here, we review the protective effect of sex hormones, particularly estrogens, progesterone, androgens and dehydroepiandrosterone, in animal models of PD and also in human studies. Data also support that drugs affecting estrogen neurotransmission such as selective estrogen receptor modulators or affecting steroid metabolism with 5α-reductase inhibitors could be repositioned for treatment of PD. Sex steroids are also modulator of neurotransmission, thus they could repurposed to treat PD motor symptoms and to modulate the response to PD medication. No drug is yet available to limit PD progression. PD is a complex disease implicating multiple pathological processes and a therapeutic strategy using drugs with several mechanisms of action, such as sex steroids and endocrine drugs are interesting repositioning options for symptomatic treatment and disease-modifying activity for PD. This article is part of the Special Issue entitled 'Drug Repurposing: old molecules, new ways to fast track drug discovery and development for CNS disorders'.

Effect of the menopausal transition and physical activity energy expenditure on inflammatory markers: a MONET group study

OBJECTIVE

Menopausal transition is usually associated with changes in body composition and a decrease in physical activity energy expenditure. Adipose tissue, especially visceral fat, is an important source of inflammatory markers, which contributes to the development of a proinflammatory state. Conversely, high levels of physical activity and exercise have an anti-inflammatory effect. This study aimed to investigate the impact of menopausal transition and physical activity on inflammatory makers.

METHODS

One hundred two healthy premenopausal women participated in a 5-year longitudinal study. The present secondary analyses were performed on 58 participants with a full set of data (age: 49.6 ± 1.7 y; body mass index: 23.3 ± 2.4 kg/m). Measures included body composition, waist circumference, fasting glucose and insulin levels, insulin sensitivity, plasma lipid levels, cardiorespiratory fitness, physical activity energy expenditure, and inflammatory markers.

RESULTS

Repeated measure analyses revealed, after the 5-year follow-up, significant increases in ferritin, interleukin-8 (IL-8), and soluble tumor necrosis factor-α receptor 1 and 2 (sTNFR1 and sTNFR2) (P < 0.001), and a significant decrease in serum high-sensitive C-reactive protein (P < 0.05). Positive correlations were observed between change (year 5 to baseline) in waist circumference and changes in high-sensitive C-reactive protein, orosomucoid (ORM), haptoglobin, and apolipoprotein B (ApoB) levels (0.26 ≤ r ≤ 0.34; P < 0.05), and between change in peripheral fat and changes in ORM, ApoB, sTNFR2 (0.28 ≤ r ≤ 0.39; P < 0.05). On the contrary, negative correlations were found between change in physical activity energy expenditure and changes in ORM as well as ApoB (r = -0.35 and r = -0.36, respectively; P < 0.05). No significant correlations were found between change in cardiorespiratory fitness, glucose, insulin, insulin sensitivity and changes in inflammatory markers. Multiple regression analyses showed that changes in physical activity energy expenditure and waist circumference together explained 23% of the individual variance of change in ORM (P < 0.05). Also, change in physical activity energy expenditure explained 15% (P < 0.05) of the variance of change in ApoB. Fat mass change explained 15% (P < 0.05) of the variance of change in IL-8, and finally change in peripheral fat explained 15% of variance of change in sTNFR2 (P < 0.05).

CONCLUSIONS

The present study indicates that the menopausal transition is accompanied by an increase in inflammatory markers, namely ferritin, IL-8, sTNFR1, and sTNFR2. The increase in IL-8 and sTNFR2 with menopause could be explained, in part, by changes in fat mass and peripheral fat, respectively.

Central Administration of Indomethacin Mitigates the Injury-Induced Upregulation of Aromatase Expression and Estradiol Content in the Zebra Finch Brain

Injury to the vertebrate brain causes neuroinflammation, characterized in part by increases in prostaglandins. In rodents and songbirds, brain injury also induces the transcription and translation of aromatase in reactive astrocytes around the site of damage. Interestingly, this induction is more rapid in female zebra finches relative to males. Induced aromatization is neuroprotective, as inhibition of aromatase and estrogen replacement, increases and decreases the extent of damage, respectively. Although the consequences of induced astrocytic aromatization are intensely studied, little is known about what factors induce aromatase. Inflammation is sufficient to induce astrocytic aromatase suggesting that the link between inflammation and aromatase expression may be causal. To test this hypothesis, adult male and female zebra finches received bilateral mechanical injuries through which either the cyclooxygenase (COX)-1/2 inhibitor indomethacin or vehicle was administered into contralateral hemispheres. Subjects were killed either 6 or 24 hours after injury. In both sexes, an enzyme immunoassay for prostaglandin E2 (PGE2) revealed that indomethacin decreased PGE2 relative to the contralateral hemisphere at both time points, suggesting that the dose and mode of administration used were successful in affecting neuroinflammation locally. Indomethacin reduced aromatase expression and 17β-estradiol (E2) content at 6 hours but not 24 hours following injury in females. However, in males, the inhibitory effect of indomethacin on aromatase and E2 was apparent at 24 but not 6 hours after treatment. These data suggest that COX activity, perhaps via consequent prostaglandin secretion, may induce aromatase expression and central E2, an effect that is detectable in temporally distinct patterns between sexes.

Integrating insulin-like growth factor 1 and sex hormones into neuroprotection: Implications for diabetes

Brain integrity and cognitive aptitude are often impaired in patients with diabetes mellitus, presumably a result of the metabolic complications inherent to the disease. However, an increasing body of evidence has demonstrated the central role of insulin-like growth factor 1 (IGF1) and its relation to sex hormones in many neuroprotective processes. Both male and female patients with diabetes display abnormal IGF1 and sex-hormone levels but the comparison of these fluctuations is seldom a topic of interest. It is interesting to note that both IGF1 and sex hormones have the ability to regulate phosphoinositide 3-kinase-Akt and mitogen-activated protein kinases-extracellular signal-related kinase signaling cascades in animal and cell culture models of neuroprotection. Additionally, there is considerable evidence demonstrating the neuroprotective coupling of IGF1 and estrogen. Androgens have also been implicated in many neuroprotective processes that operate on similar signaling cascades as the estrogen-IGF1 relation. Yet, androgens have not been directly linked to the brain IGF1 system and neuroprotection. Despite the sex-specific variations in brain integrity and hormone levels observed in diabetic patients, the IGF1-sex hormone relation in neuroprotection has yet to be fully substantiated in experimental models of diabetes. Taken together, there is a clear need for the comprehensive analysis of sex differences on brain integrity of diabetic patients and the relationship between IGF1 and sex hormones that may influence brain-health outcomes. As such, this review will briefly outline the basic relation of diabetes and IGF1 and its role in neuroprotection. We will also consider the findings on sex hormones and diabetes as a basis for separately analyzing males and females to identify possible hormone-induced brain abnormalities. Finally, we will introduce the neuroprotective interplay of IGF1 and estrogen and how androgen-derived neuroprotection operates through similar signaling cascades. Future research on both neuroprotection and diabetes should include androgens into the interplay of IGF1 and sex hormones.

The endocrine-brain-aging triad where many paths meet: female reproductive hormone changes at midlife and their influence on circuits important for learning and memory

Female mammals undergo natural fluctuations in sex steroid hormone levels throughout life. These fluctuations span from early development, to cyclic changes associated with the menstrual or estrous cycle and pregnancy, to marked hormone flux during perimenopause, and a final decline at reproductive senescence. While the transition to reproductive senescence is not yet fully understood, the vast majority of mammals experience this spontaneous, natural phenomenon with age, which has broad implications for long-lived species. Indeed, this post-reproductive life stage, and its transition, involves significant and enduring physiological changes, including considerably altered sex steroid hormone and gonadotropin profiles that impact multiple body systems, including the brain. The endocrine-brain-aging triad is especially noteworthy, as many paths meet and interact. Many of the brain regions affected by aging are also sensitive to changes in ovarian hormone levels, and aging and reproductive senescence are both associated with changes in memory performance. This review explores how menopause is related to cognitive aging, and discusses some of the key neural systems and molecular factors altered with age and reproductive hormone level changes, with an emphasis on brain regions important for learning and memory.

Disrupted female estrous cyclicity in the intrahippocampal kainic acid mouse model of temporal lobe epilepsy

Objective

Reproductive dysfunction is a comorbidity that commonly occurs with temporal lobe epilepsy (TLE). Characterization of this comorbidity in various models of TLE in mice will greatly facilitate mechanistic investigations of the relationship between reproductive disorders and seizures initiated in the hippocampus. Here we investigate the impact on female reproductive estrous cyclicity in the intrahippocampal kainic acid mouse model of TLE and demonstrate the utility of using this model for future mechanistic studies.

Methods

Kainic acid (KA) or saline vehicle was stereotaxically injected in the right dorsal hippocampus of adult female C57BL/6J mice. Development of epilepsy was assessed by video monitoring for behavioral seizures. Reproductive function was assessed by daily estrous cycle monitoring and ovarian morphology. Estrous cycles were monitored for up to 2 months after injection. Ovarian morphology was examined by histological staining and assessment of follicular and luteal development.

Results

We observed spontaneous behavioral seizures in 82% of kainic-acid-treated mice. Irregular estrous cycles developed within 2 months after kainic acid injection. Sixty-seven percent of KA-treated mice showed disrupted estrous cycles, typically characterized by increased estrous cycle length, increased time spent in diestrus (nonfertile stage), and decreased time spent in estrus by 42 days post-KA injection. The estrous cycle disruption, however, was not accompanied by major changes in ovarian morphology or follicular development. KA-treated mice also displayed increased weight gain compared to control mice.

Significance

These data indicate that comorbid female irregular estrous cyclicity arises in the intrahippocampal kainic acid mouse model of TLE. This is the first demonstration of disrupted reproductive endocrine function in a mouse model of TLE initially produced by an insult specifically targeted to the hippocampus. This model should thus be useful for basic studies investigating the neural mechanisms driving comorbid reproductive dysfunction in epilepsy in women.

The Relationship between Estrogen and Nitric Oxide in the Prevention of Cardiac and Vascular Anomalies in the Developing Zebrafish (Danio Rerio)

It has been known that both estrogen (E2) and nitric oxide (NO) are critical for proper cardiovascular system (CVS) function. It has also been demonstrated that E2 acts as an upstream effector in the nitric oxide (NO) pathway. Results from this study indicate that the use of a nitric oxide synthase (NOS) inhibitor (NOSI) which targets specifically neuronal NOS (nNOS or NOS1), proadifen hydrochloride, caused a significant depression of fish heart rates (HR) accompanied by increased arrhythmic behavior. However, none of these phenotypes were evident with either the inhibition of endothelial NOS (eNOS) or inducible NOS (iNOS) isoforms. These cardiac arrhythmias could also be mimicked by inhibition of E2 synthesis with the aromatase inhibitor (AI), 4-OH-A, in a manner similar to that of nNOSI. In both scenarios, by using an NO donor (DETA-NO) in either NO + nNOSI or E2 + AI co-treatments, fish could be significantly rescued from decreased HR and increased arrhythmias. However, the addition of an NOS inhibitor (L-NAME) to the E2 + AI co-treatment fish prevented the rescue of low heart rates and arrhythmias, which strongly implicates the NO pathway as a downstream E2 targeted molecule for the maintenance of healthy cardiomyocyte contractile conditions in the developing zebrafish. Cardiac arrhythmias could be mimicked by the S-nitrosylation pathway inhibitor DTT (1,4-dithiothreitol) but not by ODQ (1H-[1–3]oxadiazolo[4,3-a]quinoxalin-1-one), the inhibitor of the NO receptor molecule sGC in the cGMP-dependent pathway. In both the nNOSI and AI-induced arrhythmic conditions, 100% of the fish expressed the phenotype, but could be rapidly rescued with maximum survival by a washout with dantrolene, a ryanodine Ca²⁺ channel receptor blocker, compared to the time it took for rescue using a control salt solution. In addition, of the three NOS isoforms, eNOS was the one most implicated in the maintenance of an intact developing fish vascular system. In conclusion, results from this study have shown that nNOS is the prominent isoform that is responsible, in part, for maintaining normal heart rates and prevention of arrhythmias in the developing zebrafish heart failure model. These phenomena are related to the upstream stimulatory regulation by E2. On the other hand, eNOS has a minimal effect and iNOS has little to no influence on this phenomenon. Data also suggests that nNOS acts on the zebrafish cardiomyocytes through the S-nitrosylation pathway to influence the SR ryanidine Ca²⁺ channels in the excitation-coupling phenomena. In contrast, eNOS is the prominent isoform that influences blood vessel development in this model.

Menopause and Parkinson's disease. Interaction between estrogens and brain renin-angiotensin system in dopaminergic degeneration

The neuroprotective effects of menopausal hormonal therapy in Parkinson's disease (PD) have not yet been clarified, and it is controversial whether there is a critical period for neuroprotection. Studies in animal models and clinical and epidemiological studies indicate that estrogens induce dopaminergic neuroprotection. Recent studies suggest that inhibition of the brain renin-angiotensin system (RAS) mediates the effects of estrogens in PD models. In the substantia nigra, ovariectomy induces a decrease in levels of estrogen receptor-α (ER-α) and increases angiotensin activity, NADPH-oxidase activity and expression of neuroinflammatory markers, which are regulated by estrogen replacement therapy. There is a critical period for the neuroprotective effect of estrogen replacement therapy, and local ER-α and RAS play a major role. Astrocytes play a major role in ER-α-induced regulation of local RAS, but neurons and microglia are also involved. Interestingly, treatment with angiotensin receptor antagonists after the critical period induced neuroprotection.

Effects of Estrogen, Nitric Oxide, and Dopamine on Behavioral Locomotor Activities in the Embryonic Zebrafish: A Pharmacological Study

Nitric oxide (NO) has been shown to affect motor function. Specifically, NO has been shown to act through regulation of dopamine (DA) release, transporter function, and the elicitation of neuroprotection/neurodegeneration of neurons. Recently, zebrafish have been proposed to be a new model for the study of various types of motor dysfunctions, since neurotoxin damage to their nigrostriatal-like neurons exhibit motor anomalies similar to those of mammalian models and human patients. Results from this study demonstrate that when NO synthesis is inhibited in zebrafish, using a neuronal NO synthase inhibitor (nNOSI), a condition called ‘listless’ occurs, where the fish lack swimming abilities, are rigid, and have difficulty maintaining balance. Additionally, co-treatment with either NO or estrogen (E2), an upstream regulator of NO synthase, can rescue fish from the ‘listless’ phenotype caused by exposure to the neurotoxin 6-hydroxydopamine (6 OHDA). In turn, NO deprived zebrafish were rescued from the ‘listless’ phenotype when co-treated with L-DOPA, a precursor to DA. Interestingly, the longer fish are exposed to a 6 OHDA + nNOSI co-treatment, the slower the recovery after washout, compared to a single treatment of each. Most significantly, NO involvement in the motor homeostasis of the embryonic zebrafish was shown to be expressed through the NO-cGMP-dependent pathway, and response to nNOSI treatments is developmentally regulated. In conclusion, these results indicate that there is a link between E2, NO, and DA systems that regulate motor functions in the embryonic zebrafish.

Estradiol Topical Emulsion for the Treatment of Moderate-to-Severe Vasomotor Symptoms Associated with Menopause

A novel micellar, nanoparticle emulsion containing 17β-estradiol is currently available as a daily topical treatment for moderate-to-severe vasomotor symptoms associated with menopause. Applied daily to the lower extremities, the emulsion delivers 0.05 mg estradiol systemically and provides an 85% reduction in hot flash frequency versus baseline by 12 weeks of therapy. When specifically surveyed, most patients felt that this cosmetic-like delivery system was convenient and preferable to transdermal patches. Local skin reactions, all mild, were seen in 4%, and there was a low incidence of side effects that included breast pain, endometrial thickening and headache. Contraindications include those common to all estrogen-containing therapies. This formulation provides patients with a cosmetic-like treatment option that is effective and safe, delivers stable systemic estradiol levels, and may promote overall treatment compliance.

The Effect of Pueraria Lobata/Rehmannia Glutinosa and Exercise on Fatty Acid Transporters Expression in Ovariectomized Rats Skeletal Muscles

PURPOSE

Pueraria lobata/rehmannia glutinosa (PR) and exercise have been receiving a lot of attention from postmenopausal women, as a result of the side effects of estrogen replacement therapy. However, the effects of PR and exercise on fatty acid transporters (FATPs), which play essential role in fatty acid transport, have not been studied. In this study, we evaluated the effects of PR and aerobic exercise on FATP1, FABPpm and FAT/CD36 expression in ovariectomized rat skeletal muscles.

METHODS

Sixty rats were randomly divided into 6 groups: (1)HSV; high fat diet (HFD)+sedentary+vehicle, (2)HSP; HFD+sedentary+PR, (3)HSH; HFD+sedentary+17β-estradiol, (4)HEV; HFD+exercise+vehicle, (5) HEP; HFD+exercise+PR, (6)HEH; HFD+exercise+17β-estradiol. Exercise consisted of treadmill exercise (1-4th week: 15 m/min for 30 min, 5-8th week: 18 m/min for 40 min, 5 times/week).

RESULTS

Exercise does not alter FATP1 and FAT/CD36 gene levels in soleus and plantaris muscles. In contrast, exercise had main effect on up-regulation of FABPpm mRNA expression in both muscles. However, FABPpm level was not increased by exercise combined with treatments, indicative of no additive effects of PR or hormone on FABPpm gene expression. On the other hand, immunohistochemistry result showed that translocation of FATPs proteins to plasma membrane were higher in PR, exercise groups, and exercise combined with PR groups in both muscles.

CONCLUSION

These result showed that aerobic exercise and PR may help increase fat-oxidation through the induction of FABPpm, a muscle specific transporter, in OVX rat skeletal muscles. In addition, FABPpm expression is possibly regulated post-transcriptionally in exercise, or pre-translationally in PR.

Western-style diet, sex steroids and metabolism

The evolutionary transition from hunting to farming was associated with introduction of carbohydrate-rich diets. Today, the increased consumption of simple sugars and high-fat food brought about by Western-style diet and physical inactivity are leading causes of the growing obesity epidemic in the Western society. The extension of human lifespan far beyond reproductive age increased the burden of metabolic disorders associated with overnutrition and age-related hypogonadism. Sex steroids are essential regulators of both reproductive function and energy metabolism, whereas their imbalance causes infertility, obesity, glucose intolerance, dyslipidemia, and increased appetite. Clinical and translational studies suggest that dietary restriction and weight control can improve metabolic and reproductive outcomes of sex hormone-related pathologies, including testosterone deficiency in men and natural menopause and hyperandrogenemia in women. Minimizing metabolic and reproductive decline through rationally designed diet and exercise can help extend human reproductive age and promote healthy aging. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Modeling menopause: The utility of rodents in translational behavioral endocrinology research

The human menopause transition and aging are each associated with an increase in a variety of health risk factors including, but not limited to, cardiovascular disease, osteoporosis, cancer, diabetes, stroke, sexual dysfunction, affective disorders, sleep disturbances, and cognitive decline. It is challenging to systematically evaluate the biological underpinnings associated with the menopause transition in the human population. For this reason, rodent models have been invaluable tools for studying the impact of gonadal hormone fluctuations and eventual decline on a variety of body systems. While it is essential to keep in mind that some of the mechanisms associated with aging and the transition into a reproductively senescent state can differ when translating from one species to another, animal models provide researchers with opportunities to gain a fundamental understanding of the key elements underlying reproduction and aging processes, paving the way to explore novel pathways for intervention associated with known health risks. Here, we discuss the utility of several rodent models used in the laboratory for translational menopause research, examining the benefits and drawbacks in helping us to better understand aging and the menopause transition in women. The rodent models discussed are ovary-intact, ovariectomy, and 4-vinylcylohexene diepoxide for the menopause transition. We then describe how these models may be implemented in the laboratory, particularly in the context of cognition. Ultimately, we aim to use these animal models to elucidate novel perspectives and interventions for maintaining a high quality of life in women, and to potentially prevent or postpone the onset of negative health consequences associated with these significant life changes during aging.

Neuroprotective effects of estrogens: the role of cholesterol

INTRODUCTION

Experimental and clinical evidence suggests that estrogens have protective effects in the brain. Nevertheless, their potential role against neurodegenerative diseases, in particular Alzheimer's disease (AD), is still a matter of debate. The identification of the seladin-1 gene (for SELective Alzheimer's Disease INdicator-1), which appeared to be significantly less expressed in brain region affected in AD, opened a new scenario in the field of neuroprotective mechanisms. Seladin-1 was found to have neuroprotective properties through its anti-apoptotic activity. In addition, it was subsequently demonstrated that seladin-1 also has enzymatic activity, because it catalyzes the conversion of desmosterol into cholesterol. Several studies have shown that an appropriate amount of membrane cholesterol plays a pivotal role to protect nerve cells against β-amyloid toxicity in AD and to counteract the synthesis of β-amyloid.

METHODS AND RESULTS

We demonstrated that the expression of seladin-1, as well as the synthesis of cell cholesterol, is stimulated by estrogens in human neuronal precursor cells. Cholesterol enriched cells became more resistant against oxidative stress and β-amyloid toxicity. We thus hypothesized that seladin-1 might be a mediator of the neuroprotective effects of estrogens. Indeed, in cells in which seladin-1 gene expression had been silenced by siRNA the protective effects of estrogens were lost. This finding indicates that seladin-1 is a crucial mediator of the neuroprotective effects of these hormones, at least in our cell model.

CONCLUSIONS

In summary, these results establish a new link between estrogens and cholesterol, which is represented by the neuroprotective factor seladin-1.

Lower body mass index is associated with a higher risk of giant cell arteritis: a systematic review and meta-analysis

OBJECTIVE

To characterize the possible association between body mass index (BMI) and risk of giant cell arteritis (GCA).

METHODS

We conducted a systematic review of observational studies (case-control or cohort study) that (I) reported BMI of patients with GCA prior to the diagnosis of GCA compared with subjects without GCA and (II) provided relative risk (RR), odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) from its regression analysis. Meta-analysis of the included studies was then performed to estimate the pooled effect using generic variance method of DerSimonian and Laird.

RESULTS

Three studies encompassing 141 patients with GCA and 85,736 controls met our eligibility criteria and were included in the data analyses. We demonstrated a statistically significant inverse relationship between BMI and risk of subsequent development of GCA as the risk increased by 8% when BMI was reduced by 1.0 kg/m(2) (pooled OR of 0.92/kg/m(2); 95% CI, 0.88-0.96).

CONCLUSIONS

Our study demonstrated a statistically significant inverse relationship between BMI and risk of subsequent development GCA. The pathophysiologic link behind this negative correlation is not well-characterized and further investigation is required.

Cognitive functioning during long-term tamoxifen treatment in postmenopausal women with breast cancer

OBJECTIVE

Endocrine therapy is widely used-often for many years-in women with breast cancer. Yet little is known about cognitive functioning after long-term use of tamoxifen. We examine cognitive sequelae, approximately 3 years after diagnosis, in postmenopausal women with breast cancer who were treated with adjuvant tamoxifen.

METHODS

Data from participants who underwent surgical operation with or without radiotherapy, participants who received adjuvant tamoxifen, and healthy controls were collected. Neuropsychological tests were administered, and participants completed questionnaires on health-related quality of life (Quality of Life Questionnaire Core 30 and Breast Cancer-Specific Quality-of-Life Questionnaire), menopausal symptoms (Functional Assessment of Cancer Therapy-Breast endocrine symptom subscale), and anxiety and depression (Hopkins Symptom Checklist).

RESULTS

In total, 107 women participated (adjuvant tamoxifen group, n = 20; surgical operation/radiotherapy group, n = 43; healthy control group, n = 44). Women in the adjuvant tamoxifen group had received tamoxifen for a mean (SD) of 31.5 (18.6) months (range, 15-79 mo) and performed worse on verbal memory than the surgical operation/radiotherapy group (P < 0.05) and the healthy control group (P < 0.05). Participants in the adjuvant tamoxifen group performed worse on measures of fluency than healthy controls (P < 0.05). Furthermore, women in the adjuvant tamoxifen group reported worse cognitive functioning (P < 0.05) than women in the surgical operation/radiotherapy group or the healthy control group.

CONCLUSIONS

Our results provide insights into cognitive functioning in women who receive long-term adjuvant tamoxifen treatment. By adding the surgical operation/radiotherapy group, we could control for the mental and physical influences of the diagnosis and treatment of breast cancer. Cognitive domains that rely on verbal abilities (verbal memory and fluency) seem to be at risk for deterioration after treatment with tamoxifen.

Estrogen influences on neuromuscular function in postmenopausal women

Exposure to ovarian sex steroids during different life phases has long-term effects on women's health and wellbeing. Menopause is characterized by rapid decline in ovarian sex steroids already during mid-life, between the ages of 46 and 52. Due to the menopause-related hormonal changes, women in most western countries live more than one-third of their lives in postmenopausal status. The role of ovarian steroids on neuromuscular function in middle-aged and older women has been investigated since the 1980s with increasing volume of research during the last decades. This review considers how different components of the neuromuscular system may be influenced by estrogens and so affects neuromuscular function in postmenopausal women. The main focus is on muscle strength and power, which are closely associated with mobility and functional capacity among older populations. In the end of the review, we summarize recent findings on the underlying biological mechanisms in skeletal muscle that could explain the association between hormone replacement therapy and neuromuscular function among postmenopausal women.

Effect of menopausal status on carotid intima-media thickness and presence of carotid plaque in Chinese women generation population

Menopause is an important physiological stage in women's life. The potential association of menopause with carotid intima-media thickness as well as with occurrence and stability of carotid plaque in Chinese female population is unclear. We conducted a population-based, cross-sectional study by recruiting 2,131 participants aged above 40 years from northeast of China. Carotid intima-media thickness (CIMT), presence of carotid plaque and its stability were evaluated by carotid duplex sonography. Among the participants, 1,133 (53.2%) were identified to be postmenopausal. After adjusting for potential confounding factors, presence of CIMT at 50^th- 75^th and ≥75^th percentiles, carotid plaque and its unstable status were found to be significantly associated with the postmenopausal status (P < 0.001). When matched the participants by age, post-menopausal status was still associated with a higher risk of having unstable plaque. Moreover, our data show that postmenopausal status is a risk factor for intracranial arterial stenosis when compared with premenopausal status in the univariate analysis (OR = 1.314, P = 0.043), and such relationship is lost when the confounding factors are adjusted (OR = 0.828, P = 0.225). In conclusion, the vascular risk factors increase as the menopausal status changes. Compared with premenopausal status, postmenopausal status is associated with higher morbidity of CIMT, carotid plaque and its unstable status.

Effects of genistein in combination with conjugated estrogens on endometrial hyperplasia and metabolic dysfunction in ovariectomized mice

Tissue-selective estrogen complex (TSEC), which combines a selective estrogen receptor modulator (SERM) with one or more estrogens, is a novel approach to menopausal therapy. It has been demonstrated that the phytoestrogen genistein (GEN) exhibits mixed estrogen receptor agonist and antagonist activity, suggesting that GEN may have potential for use as a natural SERM. We evaluated, for the first time, the effects of GEN, conjugated estrogens (CE), and their pairing effects as a TSEC treatment on estrogen-induced endometrial hyperplasia and metabolic dysfunction in ovariectomized (OVX) mice fed a high-fat diet. CE replacement prevented fat accumulation in the adipose tissue and liver, improved glucose homeostasis, and induced endometrial hyperplasia in OVX mice. GEN at 100 mg/kg showed CE mimetic effects in preventing ovariectomy-induced metabolic dysfunctions without endometrial stimulation. Combination treatments with CE and GEN prevented metabolic dysfunctions more strongly than CE alone, but at both low and high doses, GEN did not reverse CE-induced endometrial hyperplasia. In addition, we found that in a TSEC regimen, a typical SERM raloxifene maintains the metabolic benefits of CE while simultaneously protecting the endometrium in OVX mice. These findings indicate that GEN acts as an estrogen agonist in metabolic regulation, but has no SERM function in the uteri of OVX mice.