Sex hormone signaling and regulation of immune function.

Immune responses to antigens, including innocuous, self, tumor, microbial, and vaccine antigens, differ between males and females. The quest to uncover the mechanisms for biological sex differences in the immune system has intensified, with considerable literature pointing toward sex hormonal influences on immune cell function. Sex steroids, including estrogens, androgens, and progestins, have profound effects on immune function. As such, drastic changes in sex steroid concentrations that occur with aging (e.g., after puberty or during the menopause transition) or pregnancy impact immune responses and the pathogenesis of immune-related diseases. The effect of sex steroids on immunity involves both the concentration of the ligand and the density and distribution of genomic and nongenomic receptors that serve as transcriptional regulators of immune cellular responses to affect autoimmunity, allergy, infectious diseases, cancers, and responses to vaccines. The next frontier will be harnessing these effects of sex steroids to improve therapeutic outcomes.

Impact of sex and reproductive status on the default mode network in early midlife: implications for aging of memory circuitry and function.

Alterations to the resting-state default mode network (rsDMN) are early indicators of memory decline and Alzheimer's disease (AD). Brain regions shared by the rsDMN and memory circuitry are highly sexually dimorphic. However, data are limited regarding the impact of sex and reproductive status on rsDMN connectivity and memory circuitry and function. In the current investigation, rsDMN connectivity was assessed in 180 early midlife adults aged 45 to 55 by sex and reproductive status (87 women; 93 men). Associations between left and right hippocampal connectivity of rsDMN and verbal memory encoding circuitry were examined using linear mixed models, controlled for age and parental socioeconomic status, testing interactions by sex and reproductive status. Relative to men, women exhibited greater rsDMN connectivity between the left and right hippocampus. In relation to rsDMN-memory encoding connectivity, sex differences were revealed across the menopausal transition, such that only postmenopausal women exhibited loss of the ability to decrease rsDMN left-right hippocampal connectivity during memory encoding associated with poorer memory performance. Results demonstrate that sex and reproductive status play an important role in aging of the rsDMN and interactions with memory circuitry/function. This suggests the critical importance of sex and reproductive status when studying early midlife indicators of memory decline and AD risk.

Plasma homocysteine level, estradiol level, and brain atrophy: a Mendelian randomization study.

OBJECTIVES: Observational studies link elevated plasma homocysteine (Hcy) with vascular disease. Our aim was to assess the gender difference in the association between the plasma tHcy level and brain atrophy and identify the possible influencer. We employed Mendelian randomization (MR) to explore the causal relationship between plasma tHcy level, estradiol level, and brain atrophy. METHODS: A total of 687 patients with brain atrophy were included, and gender-specific subgroup analyses in association between tHcy and brain atrophy are conducted. From genome-wide association studies, we selected genetic variants (P < 5 × 10-8) for the plasma tHcy level and estradiol level. We investigated the degree of brain atrophy (including gray matter volume and total brain volume) in the UK biobank (n = 7,916). The inverse variance-weighted and several sensitivity MR regression analyses were carried out. RESULTS: The plasma tHcy level was significantly associated with brain atrophy for females, but not for males. An MR study showed that there was little evidence of the causal link between elevated plasma tHcy and brain atrophy. On the other hand, we found evidence to support causality for genetically decreased estradiol with higher risk of brain atrophy. Furthermore, genetic predisposition to elevated plasma tHcy was associated with a lower estradiol level. CONCLUSIONS: The influence of estradiol on the association between tHcy and brain atrophy deserves further investigation.

Casein kinase 1α mediates estradiol secretion via CYP19A1 expression in mouse ovarian granulosa cells.

BACKGROUND: Casein kinase 1α (CK1α), expressed in both ovarian germ and somatic cells, is involved in the initial meiosis and primordial follicle formation of mouse oocytes. Using in vitro and in vivo experiments in this study, we explored the function and mechanism of CK1α in estrogen synthesis in mice ovarian granulosa cells. METHODS: A CK1α knockout (cKO) mouse model, targeted specifically to ovarian granulosa cells (GCs), was employed to establish the influence of CK1α on in vivo estrogen synthesis. The influence of CK1α deficiency on GCs was determined in vivo and in vitro by immunofluorescence analysis and Western blot assay. Transcriptome profiling, differentially expressed genes and gene functional enrichment analyses, and computation protein-protein docking, were further employed to assess the CK1α pathway. Furthermore, wild-type female mice were treated with the CK1α antagonist D4476 to elucidate the CK1α's role in estrogen regulation. RESULTS: Ovarian GCs CK1α deficiency impaired fertility and superovulation of female mice; also, the average litter size and the estradiol (E2) level in the serum of cKO female mice were decreased by 57.3% and 87.4% vs. control mice, respectively. This deficiency disrupted the estrous cycle and enhanced the apoptosis in the GCs. We observed that CK1α mediated the secretion of estradiol in mouse ovarian GCs via the cytochrome P450 subfamily 19 member 1 (CYP19A1). CONCLUSIONS: These findings improve the existing understanding of the regulation mechanism of female reproduction and estrogen synthesis. TRIAL REGISTRATION: Not applicable.

Estrogens and the circadian system.

Circadian rhythms are ~24 h cycles of behavior and physiology that are generated by a network of molecular clocks located in nearly every tissue in the body. In mammals, the circadian system is organized hierarchically such that the suprachiasmatic nucleus (SCN) is the main circadian clock that receives light information from the eye and entrains to the light-dark cycle. The SCN then coordinates the timing of tissue clocks so internal rhythms are aligned with environmental cycles. Estrogens interact with the circadian system to regulate biological processes. At the molecular level, estrogens and circadian genes interact to regulate gene expression and cell biology. Estrogens also regulate circadian behavior across the estrous cycle. The timing of ovulation during the estrous cycle requires coincident estrogen and SCN signals. Studies using circadian gene reporter mice have also elucidated estrogen regulation of peripheral tissue clocks and metabolic rhythms. This review synthesizes current understanding of the interplay between estrogens and the circadian system, with a focus on female rodents, in regulating molecular, physiological, and behavioral processes.

Deubiquitinase UCHL1 regulates estradiol synthesis by stabilizing voltage-dependent anion channel 2.

Lack of estradiol production by granulosa cells blocks follicle development, causes failure of estrous initiation, and results in an inability to ovulate. The ubiquitin-proteasome system plays a critical role in maintaining protein homeostasis and stability of the estrous cycle, but knowledge of deubiquitination enzyme function in estradiol synthesis is limited. Here, we observe that the deubiquitinase ubiquitin C-terminal hydrolase 1 (UCHL1) is more significant in estrous sows and high litter-size sows than in nonestrous sows and low-yielding sows. Overexpression of UCHL1 promotes estradiol synthesis in granulosa cells, and interference with UCHL1 has the opposite effect. UCHL1 binds, deubiquitinates, and stabilizes voltage-dependent anion channel 2 (VDAC2), promoting the synthesis of the estradiol precursor pregnenolone. Cysteine 90 (C90) of UCHL1 is necessary for its deubiquitination activity, and Lys45 and Lys64 in VDAC2 are essential for its ubiquitination and degradation. In vivo, compared with WT and sh-NC-AAV groups, the estrus cycle of female mice is disturbed, estradiol level is decreased, and the number of antral follicles is decreased after the injection of sh-UCHL1-AAV into ovarian tissue. These findings suggest that UCHL1 promotes estradiol synthesis by stabilizing VDAC2 and identify UCHL1 as a candidate gene affecting reproductive performance.

Evaluation of Chemical-Inducible Gene Expression Systems for Beet Cyst Nematode Infection Assays in Arabidopsis thaliana.

Cyst nematodes co-opt plant developmental programs for the establishment of a permanent feeding site called a syncytium in plant roots. In recent years, the role of plant developmental genes in syncytium formation has gained much attention. One main obstacle in studying the function of development-related genes in syncytium formation is that mutation or ectopic expression of such genes can cause pleiotropic phenotypes, making it difficult to interpret nematode-related phenotypes or, in some cases, impossible to carry out infection assays due to aberrant root development. Here, we tested three commonly used inducible gene expression systems for their application in beet cyst nematode infection assays of the model plant Arabidopsis thaliana. We found that even a low amount of ethanol diminished nematode development, deeming the ethanol-based system unsuitable for use in cyst nematode infection assays, whereas treatment with estradiol or dexamethasone did not negatively affect cyst nematode viability. Dose and time course responses showed that in both systems, a relatively low dose of inducer (1 µM) is sufficient to induce high transgene expression within 24 h of treatment. Transgene expression peaked at 3 to 5 days post-induction and began to decline thereafter, providing a perfect window for inducible transgenes to interfere with syncytium establishment while minimizing any adverse effects on root development. These results indicate that both estradiol- and dexamethasone-based inducible gene expression systems are suitable for cyst nematode infection assays. The employment of such systems provides a powerful tool to investigate the function of essential plant developmental genes in syncytium formation. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Characterization of ERα Signaling to Cell Proliferation Induced by Chronic and Pulsatile E2 Stimulation in 2D and 3D Cell Cultures.

17ß-estradiol is a hormone that plays a vital role in human physiology. It acts through estrogen receptors, specifically estrogen receptor α and estrogen receptor ß, and its action is determined by the pulsatile secretion in the bloodstream. 17ß-estradiol affects cell proliferation, and dysregulation of 17ß-estradiol:estrogen receptor α signaling contribute to the development of breast cancer. Previous research on 17ß-estradiol:estrogen receptor α signaling has primarily used two-dimensional cell cultures, which do not fully recapitulate the complexity of tumors that exist in a three-dimensional environment and do not consider the pulsatile nature of this hormone. To address these limitations, we studied 17ß-estradiol:estrogen receptor α signaling in cell proliferation using both two-dimensional and three-dimensional breast cancer cell culture models under continuous and pulsatile stimulation conditions. Results revealed that breast cancer cells grown in an alginate-based three-dimensional matrix exhibited similar responsiveness to 17ß-estradiol compared with cells grown in conventional two-dimensional culture plates. 17ß-estradiol induced the expression of proteins containing estrogen response element in the three-dimensional model. The efficacy of the antiestrogen drugs fulvestrant (ICI182,280) and 4OH-tamoxifen was also demonstrated in the three-dimensional model. These results support the use of the three-dimensional culture model for studying tumor response to drugs and provide a more realistic microenvironment for such studies. Furthermore, the study revealed that a brief 5-min exposure to 17ß-estradiol triggered a physiological response comparable with continuous hormone exposure, suggesting that the cellular response to 17ß-estradiol is more important than the continuous presence of the hormone. In conclusion, the study demonstrates that the alginate-based three-dimensional culture model is suitable for studying the effects of 17ß-estradiol and antiestrogen drugs on breast cancer cells, offering a more realistic representation of tumor-microenvironment interactions. The results also highlight the importance of considering the physiological importance of the temporal dynamics in studying 17ß-estradiol signaling and cellular responses.

The hormonal profile in women using combined monophasic oral contraceptive pills varies across the pill cycle: a temporal analysis of serum endogenous and exogenous hormones using liquid chromatography with tandem mass spectroscopy.

Oral contraceptive pills, of all types, are used by approximately 151 million women worldwide; however, a clear understanding of the concentrations of endogenous and exogenous hormones across a 28-day combination monophasic oral contraceptive pill pack is not well described. In our study of 14 female participants taking various combination monophasic oral contraceptive pills, we found significant fluctuations in endogenous and exogenous hormone levels throughout the pill cycle. Our analysis revealed significantly greater levels of ethinyl estradiol on the 20th and 21st days of active pill ingestion, compared with days 1-2 (active) and days 27-28 (inactive pill ingestion). Conversely, estradiol concentrations decreased during active pill consumption, while progestin and progesterone levels remained stable. During the 7 days of inactive pill ingestion, estradiol levels rose sharply and were significantly higher at days 27-28 compared with the mid and late active phase time points, while ethinyl estradiol declined and progestin did not change. These findings challenge the previous assumption that endogenous and exogenous hormones are stable throughout the 28-day pill cycle.NEW & NOTEWORTHY The results from this study have wide-ranging implications for research and treatment in women's health including considerations in research design and interpretation for studies including women taking oral contraceptives, the potential for more precise and personalized methods of dosing to reduce unwanted side effects and adverse events, and the potential treatment of a variety of disorders ranging from musculoskeletal to neurological with exogenous hormones.

Brown adipose tissue metabolism in women is dependent on ovarian status.

In rodents, loss of estradiol (E2) reduces brown adipose tissue (BAT) metabolic activity. Whether E2 impacts BAT activity in women is not known. BAT oxidative metabolism was measured in premenopausal (n = 27; 35 ± 9 yr; body mass index = 26.0 ± 5.3 kg/m2) and postmenopausal (n = 25; 51 ± 8 yr; body mass index = 28.0 ± 5.0 kg/m2) women at room temperature and during acute cold exposure using [11C]acetate with positron emission tomography coupled with computed tomograph. BAT glucose uptake was also measured during acute cold exposure using 2-deoxy-2-[18F]fluoro-d-glucose. To isolate the effects of ovarian hormones from biological aging, measurements were repeated in a subset of premenopausal women (n = 8; 40 ± 4 yr; BMI = 28.0 ± 7.2 kg/m2) after 6 mo of gonadotropin-releasing hormone agonist therapy to suppress ovarian hormones. At room temperature, there was no difference in BAT oxidative metabolism between premenopausal (0.56 ± 0.31 min-1) and postmenopausal women (0.63 ± 0.28 min-1). During cold exposure, BAT oxidative metabolism (1.28 ± 0.85 vs. 0.91 ± 0.63 min-1, P = 0.03) and net BAT glucose uptake (84.4 ± 82.5 vs. 29.7 ± 31.4 nmol·g-1·min-1, P < 0.01) were higher in premenopausal than postmenopausal women. In premenopausal women who underwent gonadotropin-releasing hormone agonist, cold-stimulated BAT oxidative metabolism was reduced to a similar level (from 1.36 ± 0.66 min-1 to 0.91 ± 0.41 min-1) to that observed in postmenopausal women (0.91 ± 0.63 min-1). These results provide the first evidence in humans that reproductive hormones are associated with BAT oxidative metabolism and suggest that BAT may be a target to attenuate age-related reduction in energy expenditure and maintain metabolic health in postmenopausal women.NEW & NOTEWORTHY In rodents, loss of estrogen reduces brown adipose tissue (BAT) activity. Whether this is true in humans is not known. We found that BAT oxidative metabolism and glucose uptake were lower in postmenopausal compared to premenopausal women. In premenopausal women who underwent ovarian suppression to reduce circulating estrogen, BAT oxidative metabolism was reduced to postmenopausal levels. Thus the loss of ovarian function in women leads to a reduction in BAT metabolic activity independent of age.

17ß-Estradiol reduces inhibitory synaptic currents in entorhinal cortex neurons through G protein-coupled estrogen receptor-1 activation of extracellular signal-regulated kinase.

Estrogens are believed to modulate cognitive functions in part through the modulation of synaptic transmission in the cortex and hippocampus. Administration of 17ß-estradiol (E2) can rapidly enhance excitatory synaptic transmission in the hippocampus and facilitate excitatory synaptic transmission in rat lateral entorhinal cortex via activation of the G protein-coupled estrogen receptor-1 (GPER1). To assess the mechanisms through which GPER1 activation facilitates synaptic transmission, we assessed the effects of acute 10 nM E2 administration on pharmacologically isolated evoked excitatory and inhibitory synaptic currents in layer II/III entorhinal neurons. Female Long-Evans rats were ovariectomized between postnatal day (PD) 63 and 74 and implanted with a subdermal E2 capsule to maintain continuous low levels of E2. Electrophysiological recordings were obtained between 7 and 20 days after ovariectomy. Application of E2 for 20 min did not significantly affect AMPA or NMDA receptor-mediated excitatory synaptic currents. However, GABA receptor-mediated inhibitory synaptic currents (IPSCs) were markedly reduced by E2 and returned towards baseline levels during the 20-min washout period. The inhibition of GABA-mediated IPSCs was blocked in the presence of the GPER1 receptor antagonist G15. GPER1 can modulate protein kinase A (PKA), but blocking PKA with intracellular KT5720 did not prevent the E2-induced reduction in IPSCs. GPER1 can also stimulate extracellular signal-regulated kinase (ERK), a negative modulator of GABAA receptors, and blocking activation of ERK with PD90859 prevented the E2-induced reduction of IPSCs. E2 can therefore result in a rapid GPER1 and ERK signaling-mediated reduction in GABA-mediated IPSCs. This provides a novel mechanism through which E2 can rapidly modulate synaptic excitability in entorhinal layer II/III neurons and may also contribute to E2 and ERK-dependent alterations in synaptic transmission in other brain areas.

Estrogens dynamically regulate neurogenesis in the dentate gyrus of adult female rats.

Estrone and estradiol differentially modulate neuroplasticity and cognition. How they influence the maturation of new neurons in the adult hippocampus, however, is not known. The present study assessed the effects of estrone and estradiol on the maturation timeline of neurogenesis in the dentate gyrus (DG) of ovariectomized (a model of surgical menopause) young adult Sprague-Dawley rats using daily subcutaneous injections of 17ß-estradiol, estrone or vehicle. Rats were injected with a DNA synthesis marker, 5-bromo-2-deoxyuridine (BrdU), and were perfused 1, 2, or 3 weeks after BrdU injection and daily hormone treatment. Brains were sectioned and processed for various markers including: sex-determining region Y-box 2 (Sox2), glial fibrillary acidic protein (GFAP), antigen kiel 67 (Ki67), doublecortin (DCX), and neuronal nuclei (NeuN). Immunofluorescent labeling or co-labelling of BrdU with Sox2 (progenitor cells), Sox2/GFAP (neural progenitor cells), Ki67 (cell proliferation), DCX (immature neurons), NeuN (mature neurons) was used to examine the trajectory and maturation of adult-born neurons over time. Estrogens had early (1 week of exposure) effects on different stages of neurogenesis (neural progenitor cells, cell proliferation and early maturation of new cells into neurons) but these effects were less pronounced after prolonged treatment. Estradiol enhanced, whereas estrone reduced cell proliferation after 1 week but not after longer exposure to either estrogen. Both estrogens increased the density of immature neurons (BrdU/DCX-ir) after 1 week of exposure compared to vehicle treatment but this increased density was not sustained over longer durations of treatments to estrogens, suggesting that the enhancing effects of estrogens on neurogenesis were short-lived. Longer duration post-ovariectomy, without treatments with either of the estrogens, was associated with reduced neural progenitor cells in the DG. These results demonstrate that estrogens modulate several aspects of adult hippocampal neurogenesis differently in the short term, but may lose their ability to influence neurogenesis after long-term exposure. These findings have potential implications for treatments involving estrogens after surgical menopause.

Asparagine synthetase and G-protein coupled estrogen receptor are critical responders to nutrient supply in KRAS mutant colorectal cancer.

Survival differences exist in colorectal cancer (CRC) patients by sex and disease stage. However, the potential molecular mechanism(s) are not well understood. Here we show that asparagine synthetase (ASNS) and G protein-coupled estrogen receptor-1 (GPER1) are critical sensors of nutrient depletion and linked to poorer outcomes for females with CRC. Using a 3D spheroid model of isogenic SW48 KRAS wild-type (WT) and G12A mutant (MT) cells grown under a restricted nutrient supply, we found that glutamine depletion inhibited cell growth in both cell lines, whereas ASNS and GPER1 expression were upregulated in KRAS MT versus WT. Estradiol decreased growth in KRAS WT but had no effect on MT cells. Selective GPER1 and ASNS inhibitors suppressed cell proliferation with increased caspase-3 activity of MT cells under glutamine depletion condition particularly in the presence of estradiol. In a clinical colon cancer cohort from The Cancer Genome Atlas, both high GPER1 and ASNS expression were associated with poorer overall survival for females only in advanced stage tumors. These results suggest KRAS MT cells have mechanisms in place that respond to decreased nutrient supply, typically observed in advanced tumors, by increasing the expression of ASNS and GPER1 to drive cell growth. Furthermore, KRAS MT cells are resistant to the protective effects of estradiol under nutrient deplete conditions. The findings indicate that GPER1 and ASNS expression, along with the interaction between nutrient supply and KRAS mutations shed additional light on the mechanisms underlying sex differences in metabolism and growth in CRC, and have clinical implications in the precision management of KRAS mutant CRC.

Follow-Up Study of 17-ß Estradiol, Prolactin and Progesterone with the Kinetics and Prevalence of T. gondii Infection in Pregnant Women.

Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. One-third of the world's population has come into contact with this parasite. In Mexico, the prevalence is between 15% and 50% in the general population and 34.9% in women with high-risk pregnancies. In pregnancy, the highest incidence of infection occurs in the third trimester and fetal damage is inversely proportional to gestational age. Maternal hormones play a fundamental role in the immune response. There are very few studies, with controversial results, on the levels of increased hormones and their relationship to the kinetics of T. gondii infections during pregnancy. The aim was to determine the serum levels of 17-ß estradiol, prolactin, and progesterone, and their association with anti-T. gondii antibodies' kinetics in pregnancy. Fifty-two pregnant patients were studied. A questionnaire with sociodemographic and clinical aspects was used. Afterward, 10 mL of venous blood was collected by venipuncture every trimester. The concentrations of 17-ß estradiol, progesterone, and prolactin were measured, using the ELISA method. In addition, anti-Toxoplasma IgG and IgM antibodies were also determined in the first, second, and third trimester. The prevalence of anti-Toxoplasma IgG antibodies was 26.92% in the first and second trimester and 32.7% in the third trimester. In seropositive women, 17-ß estradiol increased in the second and third trimesters of pregnancy. Progesterone increased significantly p < 0.039 in the third trimester in these women, while prolactin increased in the second trimester with a statistical significance of p < 0.021. In addition, 17-ß estradiol, progesterone, and prolactin are associated with T. gondii infection during pregnancy. New studies are necessary to clarify the specific mechanisms of immune response related to these hormones during pregnancy.

Cardiometabolic health, menopausal estrogen therapy and the brain: How effects of estrogens diverge in healthy and unhealthy preclinical models of aging.

Research in preclinical models indicates that estrogens are neuroprotective and positively impact cognitive aging. However, clinical data are equivocal as to the benefits of menopausal estrogen therapy to the brain and cognition. Pre-existing cardiometabolic disease may modulate mechanisms by which estrogens act, potentially reducing or reversing protections they provide against cognitive decline. In the current review we propose mechanisms by which cardiometabolic disease may alter estrogen effects, including both alterations in actions directly on brain memory systems and actions on cardiometabolic systems, which in turn impact brain memory systems. Consideration of mechanisms by which estrogen administration can exert differential effects dependent upon health phenotype is consistent with the move towards precision or personalized medicine, which aims to determine which treatment interventions will work for which individuals. Understanding effects of estrogens in both healthy and unhealthy models of aging is critical to optimizing the translational link between preclinical and clinical research.

Combined oral contraceptives and mental health: Are adolescence and the gut-brain axis the missing links?

Combined oral contraceptives (containing synthetic forms of estradiol and progestins) are one of the most commonly used drugs among females. However, their effects on the gut-brain axis have not been investigated to a great extent despite clear evidence that suggest bi-directional interactions between the gut microbiome and endogenous sex hormones. Moreover, oral contraceptives are prescribed during adolescence, a critical period of development during which several brain structures and systems, such as hypothalamic-pituitary-gonadal axis, undergo maturation. Considering that oral contraceptives could impact the developing adolescent brain and that these effects may be mediated by the gut-brain axis, further research investigating the effects of oral contraceptives on the gut-brain axis is imperative. This article briefly reviews evidence from animal and human studies on the effects of combined oral contraceptives on the brain and the gut microbiota particularly during adolescence.

Estradiol and progesterone in female reward-learning, addiction, and therapeutic interventions.

Sex steroid hormones like estradiol (E2) and progesterone (P4) guide the sexual organization and activation of the developing brain and control female reproductive behavior throughout the lifecycle; importantly, these hormones modulate functional activity of not just the endocrine system, but most of the nervous system including the brain reward system. The effects of E2 and P4 can be seen in the processing of and memory for rewarding stimuli and in the development of compulsive reward-seeking behaviors like those seen in substance use disorders. Women are at increased risk of developing substance use disorders; however, the origins of this sex difference are not well understood and therapeutic interventions targeting ovarian hormones have produced conflicting results. This article reviews the contribution of the E2 and P4 in females to functional modulation of the brain reward system, their possible roles in origins of addiction vulnerability, and the development and treatment of compulsive reward-seeking behaviors.

Oral contraceptives in the central nervous system: Basic pharmacology, methodological considerations, and current state of the field.

Millions of women around the world use combined oral contraceptives (OCs), yet surprisingly little is known about their central nervous system (CNS) effects. This article provides a short overview of the basic pharmacology of OCs, emphasizing features that may be relevant to understanding their effects in the CNS. Historical and recent findings from studies of cognitive function, mood, and negative affect (depressive changes under OC use) are then reviewed. We also present data from an archival dataset from our own laboratory in which we explore dysphoric changes in women using four generations of contraceptive progestins. Current data in the field are consistent with a modest effect of OC use on CNS variables, but conclusions based on current findings must be made very cautiously because of multiple methodological issues in many published studies to date, and inconsistencies in the findings. Directions for future research over the next 10 years are suggested. (150 words).

Association between serum estradiol and cardiovascular health among transgender adults using gender-affirming estrogen therapy.

Gender-affirming estrogen therapy (GAET) is commonly used for feminization in transgender and nonbinary (TNB) individuals, yet the optimal rate of change (ROC) in estradiol levels for cardiovascular health is unclear. We examined the association between serum estradiol levels and cardiovascular-related mortality, adverse events, and risk factors in TNB adults using GAET. Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, and Web of Science were systematically searched (inception-April 2023) for original articles reporting serum estradiol levels and cardiovascular-related mortality, adverse events, and risk factors in TNB adults using GAET. Data extraction was completed in duplicate following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Stratified random effect meta-analyses using serum estradiol ROC (serum estradiolbaseline - serum estradiolfollow-up/study duration) was used to assess longitudinal studies (low, 0 < ROC ≤ 1 pg/mL/mo; moderate, 1 < ROC ≤ 3 pg/mL/mo; high, ROC ≥ 3 pg/mL/mo). Thirty-five studies (13 cross-sectional, 19 cohort, and 3 trials) were included. Two studies collectively reported 50 cardiovascular-related deaths, and four collectively reported 23 adverse cardiovascular events. Nineteen studies reporting cardiovascular risk factors were meta-analyzed by ROC stratum (low = 5; moderate = 6; high = 8), demonstrating an association between moderate [0.40, 95% confidence interval (CI): 0.22, 0.59 kg/m2, I2 = 28.2%] and high (0.46, 95% CI: 0.15, 0.78 kg/m2; I2 = 0.0%) serum estradiol ROC and increased body mass index. High (-6.67, 95% CI: -10.65, -2.68 mg/dL; I2 = 0.0%) serum estradiol ROC was associated with decreased low-density lipoproteins. Low (-7.05, 95% CI: -10.40, -3.70 mmHg; I2 = 0.0%) and moderate (-3.69, 95% CI: -4.93, -2.45 mmHg; I2 = 0.0%) serum estradiol ROCs were associated with decreases in systolic blood pressure. In TNB adults using GAET, serum estradiol ROC may influence cardiovascular risk factors, which may have implications for clinical cardiovascular outcomes.NEW & NOTEWORTHY In this systematic review and meta-analysis of 35 studies involving 7,745 participants, high rates of serum estradiol change were associated with small increases in body mass index. Moderate to high rates of change were associated with decreases in low-density lipoprotein. Low rates of change were associated with small decreases in systolic blood pressure. Rate of serum estradiol change in adults using gender-affirming estrogen therapy may influence cardiovascular risk factors, though further research is warranted.

Measuring serum oestrogen levels in breast cancer survivors using vaginal oestrogens: a systematic review.

PURPOSE: Vaginal oestrogens can be used to treat genitourinary symptoms in women with early breast cancer. Studies evaluating vaginal oestrogens have commonly measured serum oestrogen levels as a surrogate marker of safety, but methods vary. We sought to summarise the data on serum oestrogen measurement in women with breast cancer using vaginal oestrogens to better understand the methods, levels and reliability. METHODS: We searched Medline, Embase, CENTRAL, SCOPUS and CINAHL from inception to October 2023 for clinical studies where serum oestrogen was measured in women with a history of early breast cancer using vaginal oestrogens. Studies with a reported testing methodology were included. RESULTS: Nine studies met the inclusion criteria for this systematic review. Methods used to measure oestradiol and oestriol in selected studies included mass spectrometry and immunoassays; several studies used more than one with variable concordance. Mass spectrometry detected oestradiol levels down to a lower limit between 1.0 pg/mL and 3.0 pg/mL. Immunoassays such as ELISA (enzyme-linked immunosorbent assay), ECLIA (enhanced chemiluminiscence immunoassay) and RIA (radioimmunoassay) had lower detection limits ranging between 0.8 pg/mL and 10 pg/mL. Studies were heterogeneous in testing techniques used, timing of testing, and the population including with subsequent varying results in the effect on oestrogens reported. CONCLUSIONS: Adopting consistent and standardised methods of measuring oestrogens in clinical trials involving women with early breast cancer on vaginal oestrogens is critical. Serum oestrogens are used as a surrogate marker of safety in this population, and good-quality data are necessary to enable clinicians and patients to feel confident in prescribing and taking vaginal oestrogens. Mass spectrometry, although more expensive, gives more reliable results when dealing with very low levels of oestrogens often found in women on aromatase inhibitors, compared to immunoassays.