The diversity of sex steroid action: regulation of metabolism by estrogen signaling

Sleep loss is a metabolic disorder

Sleep loss dysregulates cellular metabolism and energy homeostasis. Highly metabolically active cells, such as neurons, enter a catabolic state during periods of sleep loss, which consequently disrupts physiological functioning. Specific to the central nervous system, sleep loss results in impaired synaptogenesis and long-term memory, effects that are also characteristic of neurodegenerative diseases. In this review, we describe how sleep deprivation increases resting energy expenditure, leading to the development of a negative energy balance-a state with insufficient metabolic resources to support energy expenditure-in highly active cells like neurons. This disruption of energetic homeostasis alters the balance of metabolites, including adenosine, lactate, and lipid peroxides, such that energetically costly processes, such as synapse formation, are attenuated. During sleep loss, metabolically active cells shunt energetic resources away from those processes that are not acutely essential, like memory formation, to support cell survival. Ultimately, these findings characterize sleep loss as a metabolic disorder.

Metabolic Changes in Patients with Premature Ovarian Insufficiency: Adipose Tissue Focus-A Narrative Review

Background: Estrogen plays a crucial role in adipose tissue homeostasis, influencing fat distribution, lipid metabolism, and insulin sensitivity. Through estrogen receptor (ER) activation, particularly ERα, estradiol (E2) regulates adipogenesis, inhibits adipocyte hypertrophy, and promotes insulin signaling. It enhances lipid oxidation, reduces lipogenesis, and suppresses pro-inflammatory cytokine production, thereby maintaining metabolic health. Primary ovarian insufficiency (POI), characterized by estrogen deficiency before the age of 40, disrupts this regulatory network, leading to adverse metabolic effects. Objetives: This review examines the effects of estrogen on adipose tissue, lipid metabolism, and carbohydrate metabolism, with a particular focus on clinical evidence in women with POI. Methods: A narrative review of the metabolic alterations associated with POI, emphasizing the molecular, biochemical, and metabolic mechanisms underlying estrogen deficiency, with a special focus on adipose tissue. Results: Women with POI exhibit increased visceral fat accumulation, reduced lean mass, and alterations in adipokine secretion, resembling the metabolic phenotype of postmenopausal women. The decline in estrogen levels contributes to central adiposity, impaired lipid metabolism, and insulin resistance, exacerbating the risk of type 2 diabetes (T2D) and cardiovascular disease (CVD). The loss of estrogenic regulation leads to enhanced lipolysis in visceral fat, raising free fatty acid flux to the liver, promoting hepatic steatosis, and worsening insulin resistance. Studies indicate that POI patients have significantly higher total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides compared to age-matched controls, reinforcing their heightened CVD risk. Reduced sex hormone-binding globulin (SHBG) levels increase free androgen availability, aggravating central fat deposition. These metabolic disturbances can potentially accelerate atherosclerosis and vascular aging, increasing morbidity and mortality in POI patients. Conclusions: Understanding the role of estrogen in adipose tissue and its disruption in POI highlights the importance of early intervention. Although the available evidence is limited and largely extrapolated from menopause studies, strategies such as hormone replacement therapy, lifestyle modifications, and lipid profile optimization are essential to mitigate metabolic consequences and improve long-term health outcomes in women with POI.

Significant association between three atherosclerosis indexes and stroke risk

BACKGROUND

To evaluate the associations of three atherosclerosis indexes with stroke in a population aged 65 years and older.

METHODS

A sample was obtained from wave 2011 to wave 2015 of the China Health and Retirement Longitudinal Study. Multivariate logistic regression models were used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for stroke in the quartiles of three atherosclerosis indexes, and restricted cubic splines were constructed.

RESULTS

Four hundred and fifty-four of the 21,913 eligible participants had stroke. After multivariate adjustments and with respect to the lowest quartiles, the ORs (95% CIs) of stroke in the highest quartiles of the atherogenic index of plasma (AIP), the Castelli risk index I (CRI-I), and the Castelli risk index II (CRI-II) were 1.35 (0.99-1.83), 1.52 (1.13-2.06), and 1.40 (1.05-1.86), respectively. When assessed as a continuous exposure, per-unit increases in the AIP, CRI-I, and CRI-II were independently associated with a 49% (OR: 1.49, 95% CI: 1.07-2.08), 6% (OR: 1.06, 95% CI: 1.02-1.11), and 14% (OR: 1.14, 95% CI: 1.03-1.27) increase in the risk of stroke, respectively.

CONCLUSION

The three atherosclerosis indexes studied-the AIP, CRI-I, and CRI-II-were found to be predictors of stroke in a Chinese population.

Associations between maternal per- and polyfluoroalkyl substances exposure and lipid levels in maternal and cord blood: The Japan environment and Children's study

Despite numerous studies, the associations between per- and polyfluoroalkyl substances (PFAS) exposure and various lipid levels in pregnant women remain ambiguous, especially concerning the association with cord blood lipids. This analysis included 20,960 pregnant women enrolled in the Japan Environment and Children's Study, recruited between 2011 and 2014. Non-fasting plasma samples collected before 22 weeks of gestation were examined for PFAS concentrations. Additionally, non-fasting serum samples collected before, at and after 22 weeks of gestation, at birth, and from cord blood were used to measure total cholesterol (TC) and triglycerides (TG). Linear regression models were applied to quantify the association between each PFAS and various lipid metrics. Among the 28 PFAS analyzed, 7 were quantifiable in more than 80% of participants. Of these, 6 PFAS showed positive associations with TC in maternal blood before 22 weeks of gestation, a trend that remained mostly consistent for maternal blood samples in later stages. However, no associations were found with TC levels in cord blood. Regarding TG, 3 PFAS demonstrated a negative association with TG levels in maternal blood before 22 weeks of gestation, with these relationships generally persisting in later stages, while 4 PFAS were positively associated with TG in cord blood. In summary, this study identified associations between PFAS concentrations in maternal blood and lipid levels in both maternal and cord blood, with differing patterns observed between the two.

Association of systemic immunity-inflammation index with type 2 diabetes and insulin resistance in NHANES 2005-2018

Although the interplay between inflammation and diabetes is increasingly recognized, it is unclear whether the systemic immunity-inflammation index (SII), as a biomarker of systemic inflammatory response, is associated with type 2 diabetes (T2D) and insulin resistance (IR). This cross-sectional study was performed in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018, and finally enrolled 17,017 participants. To explore the relationship between SII and T2D and IR, a series of statistical analyses were conducted including weighted multivariate linear regression, logistic regression, and subgroup analysis. The fully adjusted multivariate linear regression revealed a positive correlation between SII and fasting plasma glucose (β = 0.13, 95% CI: 0.01, 0.24), fasting serum insulin (β = 12.90, 95% CI: 6.77, 19.04), and homeostasis model assessment of insulin resistance (β = 0.68, 95% CI: 0.25, 1.10). A per-SD increase in SII was found to be associated with a 4% increase in the odds of T2D, and a 5% increase in the odds of IR. The trend was significant across all SII quartile groups. Subgroup analysis revealed a stronger positive association existed between SII and T2D and IR in female, younger, and obese populations. SII was positively associated with the risk of T2D and IR, indicating that reducing SII levels may help prevent these conditions in the general population.

Identification of an ionic mechanism for ERα-mediated rapid excitation in neurons

The major female ovarian hormone, 17β-estradiol (E2), can alter neuronal excitability within milliseconds to regulate a variety of physiological processes. Estrogen receptor-α (ERα), classically known as a nuclear receptor, exists as a membrane-bound receptor to mediate this rapid action of E2, but the ionic mechanisms remain unclear. Here, we show that a membrane channel protein, chloride intracellular channel protein-1 (Clic1), can physically interact with ERα with a preference to the membrane-bound ERα. Clic1-mediated currents can be enhanced by E2 and reduced by its depletion. In addition, Clic1 currents are required to mediate the E2-induced rapid excitations in multiple brain ERα populations. Further, genetic disruption of Clic1 in hypothalamic ERα neurons blunts the regulations of E2 on female body weight balance. In conclusion, we identified the Clic1 chloride channel as a key mediator for E2-induced rapid neuronal excitation, which may have a broad impact on multiple neurobiological processes regulated by E2.

Positive association of the anti-aging protein α-Klotho with insulin resistance and its inverse L-shaped relationship with glycaemic control in the middle-aged and elderly population

PURPOSE

α-Klotho has been linked to insulin resistance (IR) in basic research. However, experimental evidence is inconsistent, and there is a lack of data from human research. This study seeks to elucidate the association of α-Klotho with IR in a nationwide, multiracial population.

METHODS

A total of 5289 participants aged 40-79 years were included in the National Health and Nutrition Examination Survey (NHANES) spanning 2007-2016. Serum α-Klotho was measured using enzyme-linked immunosorbent assays (ELISA), and IR was evaluated by the homeostatic model assessment of insulin resistance (HOMA-IR). Weighted multivariate logistic and linear regression analysis, subgroup analysis stratified by demographic characteristics, medical condition or obesity status, and sensitivity analysis using propensity score matching (PSM) were performed. Restricted cubic splines (RCS) were performed to explore the nonlinear relationship.

RESULTS

In the fully adjusted logistic regression model, a significant positive association was observed between log-transformed α-Klotho and IR (OR = 3.63, 95% CI: 1.56, 8.45), particularly in males or nonobese individuals (Pinteraction < 0.05). In the linear regression model, log10(α-Klotho) was associated with fasting blood glucose (FBG, β = 1.25, 95% CI: 0.74, 1.76) and glycosylated hemoglobin (HbA1c, β = 0.49, 95% CI: 0.20, 0.77). RCS revealed an inverse L-shaped dose-response relationship of α-Klotho with FBG and HbA1c (Pnonlinear <0.05). Beyond the inflection point of log10(α-Klotho) at 2.79, β coefficients sharply rose for these glycaemic control indicators.

CONCLUSION

The study provides clinical evidence supporting a positive association between α-Klotho and IR. Moreover, the inverse L-shaped relationship suggests that α-Klotho should reach a certain level to predict glycaemic changes effectively.

Advancements in molecular disassembly of optical probes: a paradigm shift in sensing, bioimaging, and therapeutics

The majority of self-assembled fluorescent dyes suffer from aggregation-caused quenching (ACQ), which detrimentally affects their diagnostic and therapeutic effectiveness. While aggregation-induced emission (AIE) active dyes offer a promising solution to overcome this limitation, they may face significant challenges as the intracellular environment often prevents aggregation, leading to disassembly and posing challenges for AIE fluorogens. Recent progress in signal amplification through the disassembly of ACQ dyes has opened new avenues for creating ultrasensitive optical sensors and enhancing phototherapeutic outcomes. These advances are well-aligned with cutting-edge technologies such as single-molecule microscopy and targeted molecular therapies. This work explores the concept of disaggregation-induced emission (DIE), showcasing the revolutionary capabilities of DIE-based dyes from their design to their application in sensing, bioimaging, disease monitoring, and treatment in both cellular and animal models. Our objective is to provide an in-depth comparison of aggregation versus disaggregation mechanisms, aiming to stimulate further advancements in the design and utilization of ACQ fluorescent dyes through DIE technology. This initiative is poised to catalyze scientific progress across a broad spectrum of disciplines.

Association of severity of menstrual dysfunction with cardiometabolic risk markers among women with polycystic ovary syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is associated with a wide range of unfavorable cardiometabolic risk factors, including obesity, hypertension, insulin resistance, impaired glucose metabolism, dyslipidemia, and metabolic syndrome. Compared with women with regular menstrual cycles, women with a history of irregular menstrual periods have an increased unfavorable cardiometabolic risk. Recently, the association between the severity of oligomenorrhea and hyperinsulinemia and insulin resistance has been demonstrated. However, evidence linking the severity of menstrual cyclicity with cardiometabolic risk in PCOS women is scarce.

MATERIAL AND METHODS

This work was a prospective cross-sectional study. A total of 154 women diagnosed with PCOS by the Rotterdam criteria were recruited from July 2021 to September 2022. PCOS women with eumenorrheic (eumeno group), oligomenorrhea (oligo group), and amenorrhea (ameno group) underwent history and physical examination, gonadal steroid hormone measurement, lipid profile, oral glucose tolerance test, and homeostasis model assessment of insulin resistance.

RESULTS

A trend toward an increase in unfavorable cardiometabolic risk markers including obesity, hypertension, prevalence of insulin resistance, prediabetes, dyslipidemia, and metabolic syndrome was observed in the ameno group (n = 57) as compared with the eumeno (n = 24) or oligo group (n = 73). A higher prevalence of insulin resistance (odds ratio [OR]: 3.02; 95% confidence interval [CI]: 1.03-8.81) and prediabetes (OR: 3.94; 95% CI: 1.01-15.40) was observed in the ameno group than in the eumeno group, and a higher proportion of dyslipidemia (OR: 2.44; 95% CI: 1.16-5.15) was observed in the ameno group than in the oligo group in the binary logistic regression analysis after adjusting for confounding factors.

CONCLUSIONS

PCOS women with amenorrhea show a higher prevalence of insulin resistance, prediabetes, and dyslipidemia compared with those with oligomenorrhea or eumenorrhea. The severity of menstrual dysfunction could be used as a readily obtainable marker for the identification of PCOS women at greatest risk of cardiometabolic diseases.

The therapeutic potential of irisin to mitigate the risk of metabolic syndrome in postmenopausal women

Oestradiol withdrawal at menopause predisposes women to metabolic syndrome, a cluster of interrelated conditions including obesity, insulin resistance, dyslipidaemia and hypertension that together confer an increased risk of developing type 2 diabetes mellitus and cardiovascular disease. Hormone replacement therapies are commonly used to treat acute symptoms of the perimenopausal period, and whilst they have been associated with metabolic improvements in many studies, long-term use is considered unviable. Novel approaches are required to mitigate the risk of postmenopausal metabolic syndrome. In 2012, the exercise-inducible myokine irisin was isolated from the skeletal muscle of mice and identified to have anti-obesity and antidiabetic effects in vivo. Irisin is now recognised to exert pleiotropic action on cognitive, bone and metabolic health. There is accumulating evidence from in vitro and in vivo rodent studies that irisin can mitigate each component condition of metabolic syndrome. In postmenopausal women, independent associations have been observed between (a) exercise and plasma irisin concentration and (b) plasma irisin concentration and reduced incidence of metabolic syndrome. To date, however, no study has considered the mechanistic basis by which irisin, whether exercise-induced or exogenously administered, could reduce the incidence or severity of metabolic syndrome in postmenopausal women. This review aims to analyse the literature concerning the metabolic actions of irisin, with a focus on its therapeutic potential for metabolic syndrome driven by a state of oestradiol depletion. It evaluates the practicality of exercise as a therapy and discusses other irisin-based therapeutic strategies that may alleviate postmenopausal metabolic syndrome. Finally, it highlights areas where future research is required to advance knowledge of irisin's biological action such that it could be considered a viable candidate for clinical application.

Epigenetic age acceleration and cognitive performance over time in older adults

INTRODUCTION

This study investigated whether epigenetic age acceleration (AA) is associated with the change in cognitive function and the risk of incident dementia over 9 years, separately in males and females.

METHODS

Six epigenetic AA measures, including GrimAge, were estimated in baseline blood samples from 560 Australians aged ≥70 years (50.7% female). Cognitive assessments included global function, episodic memory, executive function, and psychomotor speed. Composite cognitive scores were also generated. Dementia (Diagnostic and Statistical Manual for Mental Disorders - IV [DSM-IV] criteria) was adjudicated by international experts.

RESULTS

Associations between epigenetic AA and cognitive performance over-time varied by sex. In females only, GrimAA/Grim2AA was associated with worse delayed recall, composite cognition, and composite memory (adjusted-beta ranged from -0.1372 to -0.2034). In males only, GrimAA/Grim2AA was associated with slower processing speed (adjusted-beta, -0.3049) and increased dementia risk (adjusted hazard ratios [HRs], 1.78 and 2.00, respectively).

DISCUSSION

Epigenetic AA is associated with cognitive deterioration in later life but with evidence of sex-specific associations.

Highlights

Epigenetic age acceleration was associated with cognitive deterioration over time.However, these associations differed by sex.In females, accelerated GrimAge appeared to be a better marker of decline in memory.In males, accelerated GrimAge was associated with slower processing speed over time.Association between accelerated GrimAge and dementia risk was found only in males.

Hormonal regulation in diabetes: Special emphasis on sex hormones and metabolic traits

Diabetes constitutes a significant global public health challenge that is rapidly reaching epidemic proportions. Among the non-communicable diseases, the incidence of diabetes is rising at an alarming rate. The International Diabetes Federation has documented a 9.09% prevalence of diabetes among individuals aged between 20 and 79 years. The interplay of gonadal hormones and gender differences is critical in regulating insulin sensitivity and glucose tolerance, and this dynamic is particularly crucial because of the escalating incidence of diabetes. Variations in insulin sensitivity are observed across genders, levels of adiposity, and age groups. Both estrogen and testosterone are seen to influence glucose metabolism and insulin sensitivity. This chapter surveys the present knowledge of sex differences, sex hormones, and chromosomes on insulin imbalance and diabetes development. It further highlights the influence of metabolic traits in diabetes and changes in sex hormones during diabetic pregnancy. Notably, even stressful lifestyles have been acknowledged to induce hormonal imbalances. Furthermore, it discusses the potential of hormonal therapy to help stabilize sex hormones in diabetic individuals and focuses on the most recent research investigating the correlation between sex hormones and diabetes.

VCD-induced menopause mouse model reveals reprogramming of hepatic metabolism

OBJECTIVE

Menopause adversely impacts systemic energy metabolism and increases the risk of metabolic disease(s) including hepatic steatosis, but the mechanisms are largely unknown. Dosing female mice with vinyl cyclohexene dioxide (VCD) selectively causes follicular atresia in ovaries, leading to a murine menopause-like phenotype.

METHODS

In this study, we treated female C57BL6/J mice with VCD (160 mg/kg i.p. for 20 consecutive days followed by verification of the lack of estrous cycling) to investigate changes in body composition, energy expenditure (EE), hepatic mitochondrial function, and hepatic steatosis across different dietary conditions.

RESULTS

VCD treatment induced ovarian follicular loss and increased follicle-stimulating hormone (FSH) levels in female mice, mimicking a menopause-like phenotype. VCD treatment did not affect body composition, or EE in mice on a low-fat diet (LFD) or in response to a short-term (1-week) high-fat, high sucrose diet (HFHS). However, the transition to a HFHS lowered cage activity in VCD mice. A chronic HFHS diet (16 weeks) significantly increased weight gain, fat mass, and hepatic steatosis in VCD-treated mice compared to HFHS-fed controls. In the liver, VCD mice showed suppressed hepatic mitochondrial respiration on LFD, while chronic HFHS resulted in compensatory increases in hepatic mitochondrial respiration. Also, liver RNA sequencing revealed that VCD promoted global upregulation of hepatic lipid/cholesterol synthesis pathways.

CONCLUSION

Our findings suggest that the VCD-induced menopause model compromises hepatic mitochondrial function and lipid/cholesterol homeostasis that sets the stage for HFHS diet-induced steatosis while also increasing susceptibility to obesity.

Hyperuricemia research progress in model construction and traditional Chinese medicine interventions

Hyperuricemia (HUA), a severe metabolic disease derived from purine metabolism disorder, will lead to abnormally increased serum uric acid (SUA) levels in the body. Studies have shown that HUA is highly related to gout, hypertension, diabetes, coronary heart disease, chronic kidney diseases, and so on. Traditional Chinese medicine (TCM) shows excellent results in treating HUA because of its unique advantages of multi-metabolites and multi-targets. This article reports on the use of TCM components for uric acid (UA)-lowering activity with excellent efficacy and low side effects based on established HUA models. This work summarizes the advantages and limitations of various HUA disease models for efficacy evaluation. Applications of TCM in HUA treatment have also been discussed in detail. This paper reveals recent research progress on HUA in constructing evaluation models and systematic TCM interventions. It will provide a scientific reference for establishing the HUA model and suggest future TCM-related HUA studies.

Systematic transcriptome-wide meta-analysis across endocrine disrupting chemicals reveals shared and unique liver pathways, gene networks, and disease associations

Cardiometabolic disorders (CMD) are a growing public health problem across the world. Among the known cardiometabolic risk factors are compounds that induce endocrine and metabolic dysfunctions, such as endocrine disrupting chemicals (EDCs). To date, how EDCs influence molecular programs and cardiometabolic risks has yet to be fully elucidated, especially considering the complexity contributed by species-, chemical-, and dose-specific effects. Moreover, different experimental and analytical methodologies employed by different studies pose challenges when comparing findings across studies. To explore the molecular mechanisms of EDCs in a systematic manner, we established a data-driven computational approach to meta-analyze 30 human, mouse, and rat liver transcriptomic datasets for 4 EDCs, namely bisphenol A (BPA), bis(2-ethylhexyl) phthalate (DEHP), tributyltin (TBT), and perfluorooctanoic acid (PFOA). Our computational pipeline uniformly re-analyzed pre-processed quality-controlled microarray data and raw RNAseq data, derived differentially expressed genes (DEGs) and biological pathways, modeled gene regulatory networks and regulators, and determined CMD associations based on gene overlap analysis. Our approach revealed that DEHP and PFOA shared stable transcriptomic signatures that are enriched for genes associated with CMDs, suggesting similar mechanisms of action such as perturbations of peroxisome proliferator-activated receptor gamma (PPARγ) signaling and liver gene network regulators VNN1 and ACOT2. In contrast, TBT exhibited highly divergent gene signatures, pathways, network regulators, and disease associations from the other EDCs. In addition, we found that the rat, mouse, and human BPA studies showed highly variable transcriptomic patterns, providing molecular support for the variability in BPA responses. Our work offers insights into the commonality and differences in the molecular mechanisms of various EDCs and establishes a streamlined data-driven workflow to compare molecular mechanisms of environmental substances to elucidate the underlying connections between chemical exposure and disease risks.

VCD-induced menopause mouse model reveals reprogramming of hepatic metabolism

Menopause adversely impacts systemic energy metabolism and increases the risk of metabolic disease(s) including hepatic steatosis, but the mechanisms are largely unknown. Dosing female mice with vinyl cyclohexene dioxide (VCD) selectively causes follicular atresia in ovaries, leading to a murine menopause-like phenotype. In this study, we treated female C57BL6/J mice with VCD (160mg/kg i.p. for 20 consecutive days followed by verification of the lack of estrous cycling) to investigate changes in body composition, energy expenditure (EE), hepatic mitochondrial function, and hepatic steatosis across different dietary conditions. VCD treatment induced ovarian follicular loss and increased follicle-stimulating hormone (FSH) levels in female mice, mimicking a menopause-like phenotype. VCD treatment did not affect body composition, or EE in mice on a low-fat diet or in response to a short-term (1-week) high-fat, high sucrose diet (HFHS). However, the transition to a HFHS lowered cage activity in VCD mice. A chronic HFHS diet (16 weeks) significantly increased weight gain, fat mass, and hepatic steatosis in VCD-treated mice compared to HFHS-fed controls. In the liver, VCD mice showed suppressed hepatic mitochondrial respiration on LFD, while chronic HFHS diet resulted in compensatory increases in hepatic mitochondrial respiration. Also, liver RNA sequencing revealed that VCD promoted global upregulation of hepatic lipid/cholesterol synthesis pathways. Our findings suggest that the VCD- induced menopause model compromises hepatic mitochondrial function and lipid/cholesterol homeostasis that sets the stage for HFHS diet-induced steatosis while also increasing susceptibility to obesity.

Per- and Polyfluoroalkyl Substances (PFAS) and Lipid Trajectories in Women 45-56 Years of Age: The Study of Women's Health Across the Nation

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are associated with less favorable blood lipid profiles in epidemiological studies. However, little is known about the potential role of PFAS in longitudinal changes in lipids among midlife women even though women become more susceptible to metabolic alterations during the menopausal transition.

OBJECTIVES

To examine associations of serum PFAS concentrations with longitudinal trajectories of blood total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides in midlife women undergoing menopausal transition.

METHODS

The sample included 1,130 women from the Study of Women's Health Across the Nation 45-56 y of age at baseline (1999-2000). We measured serum PFAS concentrations including linear perfluorooctanoic acid (n-PFOA), perfluorononanoic acid (PFNA), linear and branched perfluorooctanesulfonic acid (n-PFOS and Sm-PFOS, respectively), and perfluorohexanesulfonic acid (PFHxS) at baseline. We used k-means clustering to identify subgroups with different patterns of PFAS mixture. Blood lipids were measured annually or biannually through 2016 with an average follow-up of 14.8 y. We identified longitudinal trajectories of each lipid using latent class growth models. We used multinomial log-linear models adjusted for covariates to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of lipid trajectory classes by PFAS and their mixtures.

RESULTS

Three distinct trajectories (low, middle, high) of total, LDL, and HDL cholesterol and two distinct trajectories (low and high) of triglycerides were identified. n-PFOS, Sm-PFOS, and PFHxS were positively associated with total and LDL cholesterol trajectories. n-PFOS was inversely associated with triglycerides trajectories. PFAS mixtures (high vs. low) showed positive associations with total and LDL cholesterol trajectories (high vs. low), showing ORs (95% CIs) of 1.69 (95% CI: 1.36, 2.12) and 1.79 (95% CI: 1.44, 2.22), respectively.

DISCUSSION

Concentrations of serum PFAS were positively associated with trajectories of total and LDL cholesterol, providing a line of evidence supporting adverse effects of PFAS on lipid homeostasis. https://doi.org/10.1289/EHP12351.

Non-linear association of atherogenic index of plasma with insulin resistance and type 2 diabetes: a cross-sectional study

BACKGROUND

Although there is numerous evidence on the epidemiological risk factors for insulin resistance (IR)-related metabolic diseases, there is still insufficient evidence to explore the non-linear association of Atherogenic Index of Plasma (AIP) with IR. Therefore, we aimed to elucidate the non-linear relationship between AIP and IR and type 2 diabetes (T2D).

METHODS

This cross-sectional study was conducted in the National Health and Nutrition Survey (NHANES) from 2009 to 2018. A total of 9,245 participants were included in the study. The AIP was calculated as log10 (triglycerides/high-density lipoprotein cholesterol). The outcome variables included IR and T2D defined by the 2013 American Diabetes Association guidelines. The weighted multivariate linear regression, weighted multivariate logistic regression, subgroup analysis, generalized additive model, smooth fitting curve and two-part logistic regression were adopted to reveal the relationship of AIP with IR and T2D.

RESULTS

After adjustment for age, gender, race, education level, smoking status, alcohol consumption, vigorous/moderate physical activity, body mass index, waist circumference and hypertension, we found that AIP was positively associated with fasting blood glucose (β = 0.08, 95% CI: 0.06, 0.10), glycosylated hemoglobin (β = 0.04, 95% CI: 0.39, 0.58), fasting serum insulin (β = 4.26, 95% CI: 3.73, 4.79), and homeostasis model assessment of insulin resistance (β = 0.22, 95% CI: 0.18, 0.25). Further studies found that AIP was associated with increased risk of IR (OR = 1.29, 95% CI: 1.26-1.32) and T2D (OR = 1.18, 95% CI: 1.15-1.22). However, the positive association between AIP and IR or T2D was more significant in female than in male (IR: P for interaction = 0.0135; T2D: P for interaction = 0.0024). A non-linear and inverse L-shaped association was found between AIP and IR, while a J-shaped association was found between AIP and T2D. In patients with - 0.47 < AIP < 0.45, increased AIP was significantly associated with increased risk of IR and T2D.

CONCLUSIONS

AIP showed an inverse L-shaped association with IR and a J-shaped association with T2D, indicating that AIP should be reduced to a certain level to prevent IR and T2D.

Estradiol Protects Female ApoE KO Mice against Western-Diet-Induced Non-Alcoholic Steatohepatitis

The prevalence of non-alcoholic fatty liver disease (NAFLD) and its severe form, non-alcoholic steatohepatitis (NASH), is higher in men than in women of reproductive age, and postmenopausal women are especially susceptible to developing the disease.

AIM

we evaluated if female apolipoprotein E (ApoE) KO mice were protected against Western-diet (WD)-induced NASH.

METHODS

Female ovariectomized (OVX) ApoE KO mice or sham-operated (SHAM) mice were fed either a WD or a regular chow (RC) for 7 weeks. Additionally, OVX mice fed a WD were treated with either estradiol (OVX + E2) or vehicle (OVX).

RESULTS

Whole-body fat, plasma glucose, and plasma insulin were increased and associated with increased glucose intolerance in OVX mice fed a WD (OVX + WD). Plasma and hepatic triglycerides, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) hepatic enzymes were also increased in the plasma of OVX + WD group, which was associated with hepatic fibrosis and inflammation. Estradiol replacement in OVX mice reduced body weight, body fat, glycemia, and plasma insulin associated with reduced glucose intolerance. Treatment also reduced hepatic triglycerides, ALT, AST, hepatic fibrosis, and inflammation in OVX mice.

CONCLUSIONS

These data support the hypothesis that estradiol protects OVX ApoE KO mice from NASH and glucose intolerance.

Association between triglyceride to high-density lipoprotein cholesterol ratio and type 2 diabetes risk in Japanese

Abnormal lipid metabolism is known to increases the risk for metabolic diseases, such as type 2 diabetes mellitus(T2DM). The relationship between baseline ratio of triglyceride to HDL cholesterol (TG/HDL-C) and T2DM in Japanese adults was investigated in this study. Our secondary analysis included 8419 male and 7034 female Japanese subjects who were free of diabetes at baseline. The correlation between baseline TG/HDL-C and T2DM was analyzed by a proportional risk regression model, the nonlinear correlation between baseline TG/HDL-C and T2DM was analyzed by a generalized additive model (GAM), and the threshold effect analysis was performed by a segmented regression model. We conducted subgroup analyses in different populations. During the median 5.39 years follow-up, 373 participants, 286 males and 87 females, developed diabetes mellitus. After full adjustment for confounders, the baseline TG/HDL-C ratio positively correlated with the risk of diabetes (hazard ratio 1.19, 95% confidence interval 1.09-1.3), and smoothed curve fitting and two-stage linear regression analysis revealed a J-shaped relationship between baseline TG/HDL-C and T2DM. The inflection point for baseline TG/HDL-C was 0.35. baseline TG/HDL-C > 0.35 was positively associated with the development of T2DM (hazard ratio 1.2, 95% confidence interval 1.10-1.31). Subgroup analysis showed no significant differences in the effect between TG/HDL-C and T2DM in different populations. A J-shaped relationship was observed between baseline TG/HDL-C and T2DM risk in the Japanese population. When TG/HDL-C was higher than 0.35, there was a positive relationship between baseline TG/HDL-C and the incidence of diabetes mellitus.

Sulfathiazole treats type 2 diabetes by restoring metabolism through activating CYP19A1

Globally, diabetes mellitus has been a major epidemic bringing metabolic and endocrine disorders. Currently, 1 in 11 adults suffers from diabetes mellitus, among the patients >90% contract type 2 diabetes mellitus (T2DM). Therefore, it is urgent to develop new drugs that effectively prevent and treat type 2 diabetes through new targets. With high-throughput screening, we found that sulfathiazole decreased the blood glucose and improved glucose metabolism in T2DM mice. Notably, we discovered that sulfathiazole treated T2DM by activating CYP19A1 protein to synthesize estrogen. Collectively, sulfathiazole along with CYP19A1 target bring new promise for the better therapy of T2DM.

Causal Inference of Central Nervous System-Regulated Hormones in COVID-19: A Bidirectional Two-Sample Mendelian Randomization Study

We assessed the causal association of three COVID-19 phenotypes with insulin-like growth factor 1, estrogen, testosterone, dehydroepiandrosterone (DHEA), thyroid-stimulating hormone, thyrotropin-releasing hormone, luteinizing hormone (LH), and follicle-stimulating hormone. We used bidirectional two-sample univariate and multivariable Mendelian randomization (MR) analyses to evaluate the direction, specificity, and causality of the association between CNS-regulated hormones and COVID-19 phenotypes. Genetic instruments for CNS-regulated hormones were selected from the largest publicly available genome-wide association studies of the European population. Summary-level data on COVID-19 severity, hospitalization, and susceptibility were obtained from the COVID-19 host genetic initiative. DHEA was associated with increased risks of very severe respiratory syndrome (odds ratio [OR] = 4.21, 95% confidence interval [CI]: 1.41-12.59), consistent with multivariate MR results (OR = 3.72, 95% CI: 1.20-11.51), and hospitalization (OR = 2.31, 95% CI: 1.13-4.72) in univariate MR. LH was associated with very severe respiratory syndrome (OR = 0.83; 95% CI: 0.71-0.96) in univariate MR. Estrogen was negatively associated with very severe respiratory syndrome (OR = 0.09, 95% CI: 0.02-0.51), hospitalization (OR = 0.25, 95% CI: 0.08-0.78), and susceptibility (OR = 0.50, 95% CI: 0.28-0.89) in multivariate MR. We found strong evidence for the causal relationship of DHEA, LH, and estrogen with COVID-19 phenotypes.

Environmental estrogens inhibit insulin-like growth factor (IGF) receptor mRNA expression, IGF binding, and IGF signaling ex vivo in rainbow trout (Oncorhynchus mykiss)

In this study, we used juvenile rainbow trout to examine the direct effects of selected environmental estrogens (EE), specifically, 17 β-estradiol (E2), β-sitosterol (βS), and 4-n-nonylphenol (NP), on target tissue sensitivity to insulin-like growth factor (IGF) as assessed by expression of IGF receptor type 1 (IGFR1) mRNAs and IGF-1 binding capacity, as well as on the cell signaling pathways through which EE exert their effects. E2 and NP inhibited IGFR1A and IGFR1B mRNA expression in a time- and concentration-related manner in gill and muscle; however, βS had no effect on expression of IGFR1 mRNAs in either tissue. NP reduced ¹²⁵I-IGF binding in gill and E2 and NP reduced ¹²⁵I-IGF in white muscle; βS had no effect on ¹²⁵I-IGF binding in either gill or white muscle. Treatment of gill filaments with either E2 or NP rapidly deactivated (via reduced proportion of phosphorylation) JAK2, STAT5, Akt, and ERK; βS had no effect on the activation state of any cell signaling elements tested. The effects of EE on IGFR mRNA expression in gill were estrogen receptor (ER) dependent as the inhibitory effects were rescued by the ER antagonist, ICI 182,780. All EE tested blocked growth hormone (GH)-stimulated IGFR mRNA expression in gill filaments. GH-stimulated activation of JAK2, STAT5, Akt, and ERK were blocked by E2, βS, and NP. Lastly, E2 and NP stimulated suppressor of cytokine signaling 2 (SOCS-2) mRNA expression, an effect that also was ER dependent. These results indicate that EE directly reduce the sensitivity of peripheral tissues to IGF by reducing mRNA and functional expression of IGFRs. Such inhibitory actions of EE are mediated, at least in part, by ER-dependent mechanisms that deactivate JAK, STAT, Akt, and ERK and enhance expression of SOCS-2. These findings together with our previous results show that EE retard growth of post-embryonic rainbow trout through widespread direct effects on the GH-IGF system, specifically, by reducing tissue sensitivity to GH, inhibiting IGF production, reducing tissue sensitivity to IGF, and by deactivating post-receptor IGF cell signaling pathways.

Sexual dimorphism in the molecular mechanisms of insulin resistance during a critical developmental window in Wistar rats

Background

Insulin resistance (IR) is a condition in which the response of organs to insulin is impaired. IR is an early marker of metabolic dysfunction. However, IR also appears in physiological contexts during critical developmental windows. The molecular mechanisms of physiological IR are largely unknown in both sexes. Sexual dimorphism in insulin sensitivity is observed since early stages of development. We propose that during periods of accelerated growth, such as around weaning, at postnatal day 20 (p20) in rats, the kinase S6K1 is overactivated and induces impairment of insulin signaling in its target organs. This work aimed to characterize IR at p20, determine its underlying mechanisms, and identify whether sexual dimorphism in physiological IR occurs during this stage.

Methods

We determined systemic insulin sensitivity through insulin tolerance tests, glucose tolerance tests, and blood glucose and insulin levels under fasting and fed conditions at p20 and adult male and female Wistar rats. Furthermore, we quantified levels of S6K1 phosphorylated at threonine 389 (T389) (active form) and its target IRS1 phosphorylated at serine 1101 (S1101) (inhibited form). In addition, we assessed insulin signal transduction by measuring levels of Akt phosphorylated at serine 473 (S473) (active form) in white adipose tissue and skeletal muscle through western blot. Finally, we determined the presence and function of GLUT4 in the plasma membrane by measuring the glucose uptake of adipocytes. Results were compared using two-way ANOVA (With age and sex as factors) and one-way ANOVA with post hoc Tukey’s tests or t-student test in each corresponding case. Statistical significance was considered for P values < 0.05.

Results

We found that both male and female p20 rats have elevated levels of glucose and insulin, low systemic insulin sensitivity, and glucose intolerance. We identified sex- and tissue-related differences in the activation of insulin signaling proteins in p20 rats compared to adult rats.

Conclusions

Male and female p20 rats present physiological insulin resistance with differences in the protein activation of insulin signaling. This suggests that S6K1 overactivation and the resulting IRS1 inhibition by phosphorylation at S1101 may modulate to insulin sensitivity in a sex- and tissue-specific manner.

Lipoprotein and metabolite associations to breast cancer risk in the HUNT2 study

BACKGROUND

The aim of this study was to gain an increased understanding of the aetiology of breast cancer, by investigating possible associations between serum lipoprotein subfractions and metabolites and the long-term risk of developing the disease.

METHODS

From a cohort of 65,200 participants within the Trøndelag Health Study (HUNT study), we identified all women who developed breast cancer within a 22-year follow-up period. Using nuclear magnetic resonance (NMR) spectroscopy, 28 metabolites and 89 lipoprotein subfractions were quantified from prediagnostic serum samples of future breast cancer patients and matching controls (n = 1199 case-control pairs).

RESULTS

Among premenopausal women (554 cases) 14 lipoprotein subfractions were associated with long-term breast cancer risk. In specific, different subfractions of VLDL particles (in particular VLDL-2, VLDL-3 and VLDL-4) were inversely associated with breast cancer. In addition, inverse associations were detected for total serum triglyceride levels and HDL-4 triglycerides. No significant association was found in postmenopausal women.

CONCLUSIONS

We identified several associations between lipoprotein subfractions and long-term risk of breast cancer in premenopausal women. Inverse associations between several VLDL subfractions and breast cancer risk were found, revealing an altered metabolism in the endogenous lipid pathway many years prior to a breast cancer diagnosis.

Insight into Potential Interactions of Thyroid Hormones, Sex Hormones and Their Stimulating Hormones in the Development of Non-Alcoholic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) is a common manifestation of metabolic syndrome. In addition to lifestyle, endocrine hormones play a role in the dysregulation of hepatic metabolism. The most common endocrine hormones contributing to metabolic syndrome are alterations in the levels of thyroid hormones (THs, predominantly in subclinical hypothyroidism) and of sex hormones (in menopause). These hormonal changes influence hepatic lipid and glucose metabolism and may increase hepatic fat accumulation. This review compares the effects of sex hormones, THs and the respective stimulating hormones, Thyroid-Stimulating Hormone (TSH) and Follicle-Stimulating Hormone (FSH), on the development of hepatosteatosis. TSH and FSH may be more relevant to the dysregulation of hepatic metabolism than the peripheral hormones because metabolic changes were identified when only levels of the stimulating hormones were abnormal and the peripheral hormones were still in the reference range. Increased TSH and FSH levels appear to have additive effects on the development of NAFLD and to act independently from each other.

Effects of Moderate-Intensity Physical Training on Skeletal Muscle Substrate Transporters and Metabolic Parameters of Ovariectomized Rats

A deficit of estrogen is associated with energy substrate imbalance, raising the risk of metabolic diseases. Physical training (PT) is a potent metabolic regulator through oxidation and storage of substrates transported by GLUT4 and FAT CD36 in skeletal muscle. However, little is known about the effects of PT on these carriers in an estrogen-deficit scenario. Thus, the aim of this study was to determine the influence of 12 weeks of PT on metabolic variables and GLUT4 and FAT CD36 expression in the skeletal muscle of animals energetically impaired by ovariectomy (OVX). The trained animals swam 30 min/day, 5 days/week, at 80% of the critical load intensity. Spontaneous physical activity was measured biweekly. After training, FAT CD36 and GLUT4 expressions were quantified by immunofluorescence in the soleus, as well as muscular glycogen and triglyceride of the soleus, gluteus maximus and gastrocnemius. OVX significantly reduced FAT CD36, GLUT4 and spontaneous physical activity (p < 0.01), while PT significantly increased FAT CD36, GLUT4 and spontaneous physical activity (p < 0.01). PT increased soleus glycogen, and OVX decreased muscular triglyceride of gluteus maximus. Therefore, OVX can cause energy disarray through reduction in GLUT4 and FAT CD36 and their muscle substrates and PT prevented these metabolic consequences, masking ovarian estrogen’s absence.

Reprogramming of Fatty Acid Metabolism in Gynaecological Cancers: Is There a Role for Oestradiol?

Gynaecological cancers are among the leading causes of cancer-related death among women worldwide. Cancer cells undergo metabolic reprogramming to sustain the production of energy and macromolecules required for cell growth, division and survival. Emerging evidence has provided significant insights into the integral role of fatty acids on tumourigenesis, but the metabolic role of high endogenous oestrogen levels and increased gynaecological cancer risks, notably in obesity, is less understood. This is becoming a renewed research interest, given the recently established association between obesity and incidence of many gynaecological cancers, including breast, ovarian, cervical and endometrial cancers. This review article, hence, comprehensively discusses how FA metabolism is altered in these gynaecological cancers, highlighting the emerging role of oestradiol on the actions of key regulatory enzymes of lipid metabolism, either directly through its classical ER pathways, or indirectly via the IGIFR pathway. Given the dramatic rise in obesity and parallel increase in the prevalence of gynaecological cancers among premenopausal women, further clarifications of the complex mechanisms underpinning gynaecological cancers are needed to inform future prevention efforts. Hence, in our review, we also highlight opportunities where metabolic dependencies can be exploited as viable therapeutic targets for these hormone-responsive cancers.

Metabolic effects of the schizophrenia-associated 3q29 deletion

The 1.6 Mb 3q29 deletion is associated with developmental and psychiatric phenotypes, including a 40-fold increased risk for schizophrenia. Reduced birth weight and a high prevalence of feeding disorders in patients suggest underlying metabolic dysregulation. We investigated 3q29 deletion-induced metabolic changes using our previously generated heterozygous B6.Del16^+/Bdh1-Tfrc mouse model. Animals were provided either standard chow (STD) or high-fat diet (HFD). Growth curves were performed on HFD mice to assess weight change (n = 30-50/group). Indirect calorimetry and untargeted metabolomics were performed on STD and HFD mice to evaluate metabolic phenotypes (n = 8-14/group). A behavioral battery was performed on STD and HFD mice to assess behavior change after the HFD challenge (n = 5-13/group). We found that B6.Del16^+/Bdh1-Tfrc animals preferentially use dietary lipids as an energy source. Untargeted metabolomics of liver tissue showed a strong sex-dependent effect of the 3q29 deletion on fat metabolism. A HFD partially rescued the 3q29 deletion-associated weight deficit in females, but not males. Untargeted metabolomics of liver tissue after HFD revealed persistent fat metabolism alterations in females. The HFD did not affect B6.Del16^+/Bdh1-Tfrc behavioral phenotypes, suggesting that 3q29 deletion-associated metabolic and behavioral outcomes are uncoupled. Our data suggest that dietary interventions to improve weight phenotypes in 3q29 deletion syndrome patients are unlikely to exacerbate behavioral manifestations. Our study also highlights the importance of assessing sex in metabolic studies and suggests that mechanisms underlying 3q29 deletion-associated metabolic phenotypes are sex-specific.

Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Letrozole Accelerates Metabolic Remodeling through Activation of Glycolysis in Cardiomyocytes: A Role beyond Hormone Regulation

Estrogen receptor-positive (ER+) breast cancer patients are recommended hormone therapy as a primary adjuvant treatment after surgery. Aromatase inhibitors (AIs) are widely administered to ER+ breast cancer patients as estrogen blockers; however, their safety remains controversial. The use of letrozole, an AI, has been reported to cause adverse cardiovascular effects. We aimed to elucidate the effects of letrozole on the cardiovascular system. Female rats exposed to letrozole for four weeks showed metabolic changes, i.e., decreased fatty acid oxidation, increased glycolysis, and hypertrophy in the left ventricle. Although lipid oxidation yields more ATP than carbohydrate metabolism, the latter predominates in the heart under pathological conditions. Reduced lipid metabolism is attributed to reduced β-oxidation due to low circulating estrogen levels. In letrozole-treated rats, glycolysis levels were found to be increased in the heart. Furthermore, the levels of glycolytic enzymes were increased (in a high glucose medium) and the glycolytic rate was increased in vitro (H9c2 cells); the same was not true in the case of estrogen treatment. Reduced lipid metabolism and increased glycolysis can lower energy supply to the heart, resulting in predisposition to heart failure. These data suggest that a letrozole-induced cardiac metabolic remodeling, i.e., a shift from β-oxidation to glycolysis, may induce cardiac structural remodeling.

Crocetin Alleviates Ovariectomy-Induced Metabolic Dysfunction through Regulating Estrogen Receptor β

Metabolic dysfunction (MD) is a major health problem threatening the life quality of menopausal women. Saffron has been widely used in herb prescriptions for treating menopausal syndrome. However, the pharmacological effects and mechanisms of saffron are poorly understood. Here, we investigated the effect of crocin, the major ingredient of saffron and its active metabolite in blood, crocetin, on MD and lipid metabolism in ovariectomized (OVX) mice and 3T3-L1 adipocytes. The present study showed that intragastric treatment of crocin prevented weight gain, fat accumulation, and insulin resistance in OVX mice by increasing energy expenditure and fat oxidation. Mechanistically, crocin influenced adipose tissue homeostasis by regulating adipogenic and lipolytic factors, which was strongly associated with the restoration of the downregulated ERβ function in white adipose tissue (WAT). In vitro, crocetin facilitated lipid metabolism in an ERβ-dependent manner. Our results demonstrated the beneficial effects of crocetin/crocin-mediated intervention against metabolic dysfunction, revealing a prospective therapeutic application in menopausal women.

In Silico Prediction of Steroids and Triterpenoids as Potential Regulators of Lipid Metabolism

This review focuses on a rare group of steroids and triterpenoids that share common properties as regulators of lipid metabolism. This group of compounds is divided by the type of chemical structure, and they represent: aromatic steroids, steroid phosphate esters, highly oxygenated steroids such as steroid endoperoxides and hydroperoxides, α,β-epoxy steroids, and secosteroids. In addition, subgroups of carbon-bridged steroids, neo steroids, miscellaneous steroids, as well as synthetic steroids containing heteroatoms S (epithio steroids), Se (selena steroids), Te (tellura steroids), and At (astatosteroids) were presented. Natural steroids and triterpenoids have been found and identified from various sources such as marine sponges, soft corals, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in fungi, fungal endophytes, and plants. The pharmacological profile of the presented steroids and triterpenoids was determined using the well-known computer program PASS, which is currently available online for all interested scientists and pharmacologists and is currently used by research teams from more than 130 countries of the world. Our attention has been focused on the biological activities of steroids and triterpenoids associated with the regulation of cholesterol metabolism and related processes such as anti-hyperlipoproteinemic activity, as well as the treatment of atherosclerosis, lipoprotein disorders, or inhibitors of cholesterol synthesis. In addition, individual steroids and triterpenoids were identified that demonstrated rare or unique biological activities such as treating neurodegenerative diseases, Alzheimer's, and Parkinson's diseases with a high degree of certainty over 95 percent. For individual steroids or triterpenoids or a group of compounds, 3D drawings of their predicted biological activities are presented.

Environmental estrogens inhibit the expression of insulin-like growth factor mRNAs in rainbow trout in vitro by altering activation of the JAK-STAT, AKT-PI3K, and ERK signaling pathways

Environmental estrogens (EE) have been found to disrupt a host of developmental, reproductive, metabolic, and osmoregulatory process in a wide-range of animals, particularly those in aquatic ecosystems where such compounds concentrate. Previously, we showed that EE inhibited post-embryonic organismal growth of rainbow trout in vivo, but the precise mechanism(s) through which EE exert their growth inhibiting effects remain unknown. In this study, we used rainbow trout (Oncorhynchus mykiss) as a model to investigate the direct effects of 17β-estradiol (E2), β-sitosterol (βS), and 4-n-nonylphenol (NP) on the synthesis of insulin-like growth factors (IGFs) and to elucidate the mechanism(s) by which EEs exert such effects. E2, βS, and NP significantly inhibited the expression of both IGF-1 and IGF-2 mRNAs in liver and gill in a time- and concentration-related manner. Although the response evoked by each EEs on the expression of IGF mRNAs was similar, the potency and efficacy varied with EE; the rank order potency/efficacy was as follows: E2 > NP > βS. The effects of EEs on the expression of IGF mRNAs was blocked by the estrogen receptor (ER) antagonist, ICI 182780. The mechanism(s) through which EEs inhibit IGF mRNA expression were investigated in isolated liver cells in vitro. EE treatment deactivated JAK, STAT, ERK, and AKT. Moreover, blockade of growth hormone (GH)-stimulated IGF expression by EE was accompanied by deactivation of JAK, STAT, ERK, and AKT. EEs also increased the expression of suppressor of cytokine signaling 2 (SOCS-2), a known inhibitor of JAK-2--an action that also was blocked by ICI 182780. These results indicate that EEs directly inhibit the expression of IGF mRNAs by disrupting GH post-receptor signaling pathways (e.g., JAK, STAT, ERK, and AKT) in an ER-dependent manner.

17β-Estradiol-Induced Conformational Changes of Human Microsomal Triglyceride Transfer Protein: A Computational Molecular Modelling Study

Human microsomal triglyceride transfer protein (hMTP) plays an essential role in the assembly of apoB-containing lipoproteins, and has become an important drug target for the treatment of several disease states, such as abetalipoproteinemia, fat malabsorption and familial hypercholesterolemia. hMTP is a heterodimer composed of a larger hMTPα subunit and a smaller hMTPβ subunit (namely, protein disulfide isomerase, hPDI). hPDI can interact with 17β-estradiol (E₂), an endogenous female sex hormone. It has been reported that E₂ can significantly reduce the blood levels of low-density lipoprotein, cholesterol and triglyceride, and modulate liver lipid metabolism in vivo. However, some of the estrogen’s actions on lipid metabolism are not associated with estrogen receptors (ER), and the exact mechanism underlying estrogen’s ER-independent lipid-modulating action is still not clear at present. In this study, the potential influence of E₂ on the stability of the hMTP complex is investigated by jointly using multiple molecular dynamics analyses based on available experimental structures. The molecular dynamics analyses indicate that the hMTP complex in the presence of E₂ has reduced interface contacts and surface areas. A steered molecular dynamics analysis shows that the forces required to separate the two subunits (namely, hPDI and hMTPα subunit) of the hMTP complex in the absence of E₂ are significantly higher than the forces required to separate the complex in which its hPDI is already bound with E₂. E₂ makes the interface between hMTPα and hPDI subunits more flexible and less stable. The results of this study suggest that E₂-induced conformational changes of the hMTP complex might be a novel mechanism partly accounting for the ER-independent lipid-modulating effect of E₂.

Liraglutide improves lipid and carbohydrate metabolism of ovariectomized rats

Considering that post-menopausal women and ovariectomized rodents develop obesity associated with increased visceral fat, this study was developed to investigate if liraglutide, a glucagon-like peptide 1 (GLP1) analogue, could improve the metabolism of estrogen (E2) deficient females. Wistar rats were ovariectomized (OVX), and subdivided in four groups: sham saline, sham liraglutide, OVX saline, and OVX liraglutide. After sixty days, metabolic parameters of blood, heart, liver, brown (BAT) and white adipose tissue (WAT) visceral depots, and, heart oxidative homeostasis, were evaluated. Castration increased the animals' body weight, the relative weight of the WAT depots, hepatic triglycerides and cardiac glycogen content. Liraglutide treatment reversed these effects, decreased WAT depots weight and increased glucose oxidation and lipogenesis in BAT and WAT. In addition, liraglutide enhanced adrenalin (A) lipolytic effect. These results indicate that liraglutide may be a promising treatment to restore lipid homeostasis and prevent weight gain associated with E2 deficiency.

Is the beta estradiol receptor receiving enough attention for its metabolic importance in postmenopause?

The relationship between menopause and the development of metabolic diseases is well established. In postmenopause women, there is an expansion of visceral white adipose tissue (WATv), which highly contributes to the rise of circulating lipids. Meanwhile, muscle glucose uptake decreases and hepatic glucose production increases. Consequently, in the pancreas, lipotoxicity and glycotoxicity lead to deficient insulin production. These factors initiate an energy imbalance and enhance the probability of developing cardiovascular and metabolic diseases. Although the activation of estradiol receptors (ER) has been shown to be beneficial for the WAT stock pattern, leading to the insulin-sensitive phenotype, authors have described the risk of these receptors' activation, contributing to neoplasia development. The selective activation of beta-type ER (ERβ) seems to be a promising strategy in the treatment of energy imbalance, acting on several tissues of metabolic importance and allowing an intervention with less risk for the development of estrogen-dependent neoplasia. However, the literature on the risks and benefits of selective ERβ activation still needs to increase. In this review, several aspects related to ERβ were considered, such as its physiological role in tissues of energy importance, beneficial effects, and risks of its stimulation during menopause. PubMed, SciELO, Cochrane, and Medline/Bireme databases were used in this study.

Prevalence of Abdominal Obesity in Chinese Middle-Aged and Older Adults with a Normal Body Mass Index and Its Association with Type 2 Diabetes Mellitus: A Nationally Representative Cohort Study from 2011 to 2018

BACKGROUND

Few studies have focused on the prevalence of abdominal obesity in Chinese middle-aged and older adults with a normal body mass index (BMI). Furthermore, it is still unclear whether abdominal obesity is an independent risk factor for type 2 diabetes mellitus (T2DM). Participants with a normal BMI are usually neglected during assessments of abdominal obesity-associated T2DM risk since the current recommendations for medical interventions are mainly focused on overall body mass index rather than fat deposition patterns.

METHODS

In this study, 7942 normal-BMI participants aged over 45 years from the China Health and Retirement Longitudinal Study were included to assess the prevalence of abdominal obesity defined by waist circumference (WC) or waist-to-height ratio (WHtR). In addition, 4348 normal-BMI individuals with no diabetes at baseline were included to evaluate the association between abdominal obesity and the risk of T2DM with the Cox proportional hazards model.

RESULTS

The prevalence (95% confidence interval, CI) of increased WC and substantially increased WC among adults with a normal BMI was 22.0% (21.1%-22.9%) and 18.1% (17.3%-19.0%), respectively. The adjusted hazard ratios and 95% CIs for T2DM incidence were 1.39 (1.05-1.85) and 1.89 (1.42-2.53) for those with increased WC and substantially increased WC, respectively, compared to the individuals with a normal WC. Similar HRs were obtained for the association between WHtR and the risk of T2DM. In prediabetic patients, the HRs (95% CIs) for new-onset T2DM for those with increased WC and substantially increased WC were 1.85 (1.27-2.69) and 2.46 (1.67-3.61), respectively, when compared with individuals with normal WC. This positive association was observed in women but not in men or adults with normal glucose tolerance (NGT).

CONCLUSION

Abdominal obesity is highly prevalent among middle-aged and older Chinese adults with a normal BMI, and maintaining a normal waist circumference may be beneficial in the prevention of T2DM.

Construction of time-response curve for neuronal and vascular endothelial dysfunction in ovariectomized rats

BACKGROUND:

Studies have shown that there is a critical time period to start hormone therapy after the loss of ovarian function during menopause. The length of estrogen deprivation may evolve different pathophysiological manifestations.

OBJECTIVE:

The aim of the present study was to investigate behavioral, biochemical, and molecular alterations at different time points after surgical menopause with an aim and identify various pathophysiological targets to exploit “window of opportunity” and to design newer therapeutic modalities for menopause-associated neurobehavioral and vascular deficits.

MATERIALS AND METHODS:

Bilateral ovariectomy was performed to induce surgical menopause and estrogen deficiency state. Menopause-associated neuronal and vascular dysfunctions were noted after 1, 2, and 3 months of the study.

RESULTS:

Neuronal and vascular endothelial dysfunction post ovariectomy revealed that behavioral, biochemical, molecular, and vascular endothelial dysfunction appeared after 1 month of ovariectomy except hyperglycemia, which occurs after 3 months.

CONCLUSIONS:

Time-response studies measuring behavioral, biochemical, and molecular markers at various time points after ovariectomy reveal that there is a fast onset of neuronal and vascular complications, but the duration of insulin resistance is a relatively late phenomenon.

Aerobic or resistance training improves autonomic control of circulation in oophorectomized rats with cardiometabolic dysfunctions: Impact on renal oxidative stress

Cardiovascular autonomic dysfunction is associated with end organ damage and increased risk of mortality. Menopause and metabolic syndrome increase the risk for cardiorenal complications. In this study, we investigated the effects of aerobic or resistance exercise training on autonomic control of circulation and renal oxidative stress in a model of menopause and metabolic syndrome. Female Wistar rats and spontaneously hypertensive rats (SHR) were divided into 5 groups (n = 8): control (C), hypertensive (H), and sedentary (FHO), aerobic trained (FHOTa) and resistance trained (FHOTr) oophorectomized hypertensive treated with fructose (100 mg/mL drink water for 19 weeks). The FHO group presented increased vascular sympathetic modulation (LF-SBP), impaired baroreflex sensitivity (BRS) associated with increased blood pressure (BP) when compared to the H group. Aerobic exercise training enhanced tachycardic responses, while resistance training improved bradycardic responses to BP changes, thus ameliorating BRS. Moreover, despite unchanged BP, both exercise training protocols were effective in preventing increase in LF-SBP, reduction in systemic nitric oxide bioavailability (NOx), and increase in oxidative stress in the renal tissue, by decreasing lipid and protein oxidation in renal tissue. Positive correlation between LF-SBP and renal lipoperoxidation (r = 0.63, p < 0.05), as well as a negative correlation between NOx and renal lipoperoxidation (r = -0.66, p < 0.05) were observed. In conclusion, both aerobic and resistance exercise training were effective in improving autonomic control of circulation and reducing renal oxidative stress, thus attenuating the deleterious effects induced by arterial hypertension and fructose overload in female rats after ovarian hormone deprivation.

Activation of Estrogen Receptor G Protein-Coupled Receptor 30 Enhances Cholesterol Cholelithogenesis in Female Mice

BACKGROUND AND AIMS

Estrogen is an important risk factor for cholesterol gallstone disease because women are twice as likely as men to form gallstones. The classical estrogen receptor α (ERα), but not ERβ, in the liver plays a critical role in the formation of estrogen-induced gallstones in female mice. The molecular mechanisms underlying the lithogenic effect of estrogen on gallstone formation have become more complicated with the identification of G protein-coupled receptor 30 (GPR30), an estrogen receptor.

APPROACH AND RESULTS

We investigated the biliary and gallstone phenotypes in ovariectomized female GPR30^-/- , ERα^-/- , and wild-type mice injected intramuscularly with the potent GPR30-selective agonist G-1 at 0 or 1 μg/day and fed a lithogenic diet for 8 weeks. The activation of GPR30 by G-1 enhanced cholelithogenesis by suppressing expression of cholesterol 7α-hydroxylase, the rate-limiting enzyme for the classical pathway of bile salt synthesis. These metabolic abnormalities led to an increase in biliary cholesterol concentrations in company with hepatic hyposecretion of biliary bile salts, thereby inducing cholesterol-supersaturated gallbladder bile and accelerating cholesterol crystallization. G-1 also impairs gallbladder emptying, leading to sluggish gallbladder motility and promoting the development of biliary sludge in the early stage of gallstone formation. The prevalence rates of gallstones were 80% in wild-type and ERα^-/- mice treated with G-1 compared to 10% in wild-type mice receiving no G-1. However, no gallstones were formed in GPR30^-/- mice treated with G-1.

CONCLUSIONS

GPR30 produces additional lithogenic actions, working independently of ERα, to increase susceptible to gallstone formation in female mice; both GPR30 and ERα are potential therapeutic targets for cholesterol gallstone disease, particularly in women and patients exposed to high levels of estrogen.

Association of TG/HDLC ratio trajectory and risk of type 2 diabetes: A retrospective cohort study in China

BACKGROUND

The association of ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDL-C ratio) change trajectory with risk of type 2 diabetes mellitus (T2DM) remains unknown. The aim of this study was to evaluate the association between risk of T2DM and TG/HDL-C ratio change trajectory.

METHODS

A total of 18 444 participants aged 18-80 years old were included in this cohort study. Linear regression and quadratic regression models were used to determine the TG/HDL-C ratio change trajectory. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between TG/HDL-C ratio change trajectory and probability of T2DM.

RESULTS

T2DM developed in 714 participants during a median follow-up of 5.74 years (92 076.23 person-years of follow-up). After adjusting for baseline potential confounders, odds of T2DM were greater for participants with the increasing, U-shape, bell-shape, and other shape change vs decreasing change (adjusted OR [aOR] 2.01, 95% CI 1.42-2.81; 1.56, 1.15-2.13; 1.60, 1.17-2.20; and 1.49, 1.13-2.00, respectively). The results were robust in the sensitivity analyses on excluding baseline participants with T2DM. Moreover, the associations remained significant with male sex, age <60 years and body mass index <24 kg/m2 .

CONCLUSIONS

This retrospective study revealed increased probability of T2DM with increasing, U-shape, bell-shape, and other-shape TG/HDL-C ratio change trajectories, especially with male sex, age <60 years and body mass index <24 kg/m2 .

Critical role of estrogen in the progression of chronic liver diseases

BACKGROUND

Estrogens regulate sexual function and also have a significant role in various pathophysiological processes. Estrogens have a non-reproductive role as the modulators of the immune system, growth, neuronal function, and metabolism. Estrogen receptors are expressed in the liver and their impaired expression and function are implicated with obesity and liver associated metabolic dysfunctions. The purpose of the current review is to discuss the disparity role of estrogens on several forms of liver diseases.

DATA SOURCES

A comprehensive search in PubMed and EMBASE was conducted using the keywords "estrogens and liver diseases", "estradiol and liver diseases", "hormones and liver diseases", "endocrine function in liver diseases", and "female hormones in liver diseases". Relevant papers published before September 30, 2019 were included.

RESULTS

The present review confirms the imperative role of estrogen in various forms of chronic liver diseases. Estrogens play a key role in maintaining homeostasis and make the liver less susceptible to several forms of chronic liver diseases in healthy premenopausal individuals. In contrast, clinical studies also showed increased estrogen levels with chronic liver diseases.

CONCLUSIONS

Several studies reported the protective role of estrogens in chronic liver diseases and this has been widely accepted and confirmed in experimental studies using ovariectomized rat models. However, in a few clinical studies, increased estrogen levels are also implicated in chronic liver diseases. Therefore, further studies are warranted at molecular level to explore the role of estrogen in various forms of chronic liver diseases.

Sex differences in body composition, metabolism-related hormones, and energy homeostasis during aging in Wistar rats

Aging affects the body composition and balance of energy metabolism. Here, we collected in a single work several physiological parameters to show how aging and sex differences can influence energy homeostasis. Body mass index (BMI), Lee index, glucose tolerance, glycemia, and lipidogram in fasting were measured in male and female Wistar rats at the ages of 2, 6, 9, 12, and 18 months. We also measured the lipid profile, free fatty acids, glycerol, glycemia, leptin, adiponectin, insulin, corticosterone (CORT), prolactin (PRL), thyroid stimulated hormone, and triiodothyronine (T3) in 3- and 18-month-old rats of both sexes, fed ad libitum. Animals were classified as obese beginning at 2 months in males and 6 months in females. Aged male rats showed hyperglycemia and glucose intolerance compared to young males and old females. In the ad libitum condition, the 18-month males presented higher serum levels of triglycerides, total cholesterol, and free fatty acids than females. The 18-month-old females had higher PRL and CORT concentration than males, but insulin and T3 were higher in 18-month-old males than females. Our work demonstrated that aging processes on energy metabolism in rats is sex specific, with a better lipid profile and glucose tolerance in aged females.

Developmental programming of insulin resistance: are androgens the culprits?

Insulin resistance is a common feature of many metabolic disorders. The dramatic rise in the incidence of insulin resistance over the past decade has enhanced focus on its developmental origins. Since various developmental insults ranging from maternal disease, stress, over/undernutrition, and exposure to environmental chemicals can all program the development of insulin resistance, common mechanisms may be involved. This review discusses the possibility that increases in maternal androgens associated with these various insults are key mediators in programming insulin resistance. Additionally, the intermediaries through which androgens misprogram tissue insulin sensitivity, such as changes in inflammatory, oxidative, and lipotoxic states, epigenetic, gut microbiome and insulin, as well as data gaps to be filled are also discussed.

Modulation of the hepatic expression of miR-33 and miR-34a possibly mediates the metabolic effects of estrogen in ovariectomized female rats

Estrogen and the estrogen receptors (ERs) are well-known regulators of several aspects of glucose and lipid metabolism. Meanwhile, the underlying mechanistic role of estrogens in regulating metabolic health remains largely unknown. Hence, the study was designed to tackle the possible contribution of the hepatic expression of miR-33, miR-21 and miR-34a and their target genes as the underlying mechanism of the metabolic effects of estrogen in ovariectomized rats. Forty female rats were ovariectomized (OVX), treated with estrogen and/or fulvestrant for 28 days and compared with untreated or treated sham operated rats. Estradiol amended the metabolic abnormalities in the OVX rats, witnessed by decreasing blood sugar, insulin and HOMA-IR as well as correcting the disrupted serum and hepatic lipids. Estradiol increased the hepatic expression of miR-33 and inhibited that of miR-34a and miR-21, leading to adjusting the gene expression and the protein level of their targets, sterol regulatory element-binding proteins-1c (SREBP-1c), fatty acid synthase (FASN), high mobility group (HMG) Box Transcription Factor 1 (HBP1) and Sirtuin 1 (SIRT1), receptively. However, estrogen had no significant effects on HBP1 protein. These effects were almost completely inhibited by fulvestrant, an estrogen receptor blocker, to the extent that fulvestrant had similar metabolic disorders to that of ovariectomization. In conclusion, estrogen replacement therapy in OVX females significantly ameliorated the metabolic derangements of insulin resistance, dyslipidemia and hepatic fat accumulation possibly via corrections of hepatic expression of miR-33 and miR-34a; effects that were mediated through the receptor-mediated signaling of ERs as confirmed by fulvestrant.

Urinary cadmium and timing of menarche and pubertal development in girls

BACKGROUND

Cadmium (Cd) is a developmental toxicant that is released into the environment during industrial processes. Previous animal studies suggest that Cd may impact the onset of puberty.

OBJECTIVES

To determine whether Cd exposure, measured as urinary Cd concentration, was associated with ages at menarche and pubertal development.

METHODS

A cohort of 211 girls, ages 10-13 years at baseline, was followed for up to two years. Girls completed an interview and self-assessment of Tanner stages of breast development and pubic hair growth. They were followed monthly until menarche. Urinary Cd concentrations were measured in overnight urine specimens. Multivariable Cox regression was used to evaluate the association between urinary Cd and age at menarche and cumulative logit regression was used to evaluate the associations between urinary Cd and breast development and pubic hair growth.

RESULTS

The baseline geometric mean creatinine-adjusted Cd concentration was 0.22 μg/g creatinine (geometric standard deviation = 1.6) and decreased with increasing age (p-trend = 0.04). Cd levels were higher among Asian than White girls or girls of other/mixed race/ethnicity (p = 0.04). In multivariable analyses, girls with urinary Cd ≥ 0.4 μg/L were less likely to have attained menarche than girls with urinary Cd < 0.2 μg/L (hazard ratio = 0.42; 95% confidence interval, 0.23-0.78). Urinary Cd was negatively associated with pubic hair growth (p-trend = 0.01) but not with breast development (p-trend = 0.72) at baseline.

CONCLUSIONS

These findings suggest that a higher Cd body burden may delay some aspects of pubertal development among girls.

Effect of herbal extract Eurycoma longifolia (Physta®) on female reproductive hormones and bone biochemical markers: an ovariectomised rat model study

BACKGROUND

Each year 1.5 million women experience menopause when menstrual cycles cease resulting from the loss of ovarian function and oestrogen deprivation, a hormone that helps prevent bone loss. This study investigated the effects of Physta®, a standardized herbal extract of Eurycoma longifolia Jack (PEL), on hormonal balance and parameters associated with hormonal imbalance, namely body and uterus weight and bone biochemical markers relevant in menopausal symptoms.

METHODS

Forty-eight Sprague Dawley rats were randomly divided into six groups of eight rats each: (A) Sham operated; control (B) Untreated (ovariectomised (OVX) with vehicle), (C) PEL 100 (OVX + 100 mg/kg body weight (bw)), (D) PEL 300 (OVX + 300 mg/kg bw), (E) PEL 500 (OVX + 500 mg/kg bw) and (F) Positive control, testosterone undecanoate (TU) (OVX+ 10 mg/kg bw). Group A and B received daily oral administrations of the vehicle, Group C-E received daily oral administration of PEL and Group F received testosterone undecanoate intramuscularly weekly. At the end of 8 weeks, serum calcium, phosphate, bone alkaline phosphatase (BALP), osteocalcin, follicle stimulating hormone (FSH), luteinising hormone (LH), oestrogen, progesterone and testosterone were measured, then the animals were sacrificed and uterus was isolated, while weight was recorded in all experimental groups.

RESULTS

Treatment of OVX rats with PEL at a dose of 500 mg/kg showed decreased serum FSH (P < 0.001, 4.25 ± 0.22 mIU/ml) and LH (NS, 4.07 ± 0.12 mIU/ml), while there was a significant increase in progesterone (P < 0.05, 2.48 ± 0.08 ng/ml) and oestrogen (P < 0.05, 11.02 ± 0.13 pg/ml) levels when compared to untreated group. PEL treatment at doses of 100 mg/kg, 300 mg/kg and 500 mg/kg showed a non-significant but increasing trend in serum calcium, phosphate, bone alkaline phosphate and testosterone levels. Ovariectomy resulted in a significant reduction (P < 0.001, 238.81 ± 5.39 mg) in uterus weight in the ovariectomised rats, which was alleviated in all PEL treated ovariectomised rats with an increasing trend of uterine weight.

CONCLUSION

The results suggest that PEL could be protective and beneficial for the management of reproductive hormone and bone markers. Therefore, it could be used to address hormonal imbalances and symptoms associated with menopause.

Endocrine Disruptor Bisphenol A (BPA) Triggers Systemic Para-Inflammation and is Sufficient to Induce Airway Allergic Sensitization in Mice

Allergic airway diseases are accompanied by increased permeability and an inflammatory state of epithelial barriers, which are thought to be susceptible to allergen sensitization. Although exogenous drivers (proteases, allergens) of epithelial barrier disruption and sensitization are well studied, endogenous contributors (diet, xenobiotics, hormones, and metabolism) to allergic sensitization are much less understood. Xenoestrogens are synthetic or natural chemical compounds that have the ability to mimic estrogen and are ubiquitous in the food and water supply of developed countries. By interfering with the estrogen produced by the endocrine system, these compounds have the systemic potential to disrupt the homeostasis of multiple tissues. Our study examined the potential of prototypical xenoestrogen bisphenol A (BPA) to disrupt epithelial homeostasis in vitro and promote allergic responses in vivo. We found that BPA exposure in epithelial cultures in vitro significantly inhibited epithelial cell proliferation and wound healing, as well as promoted the expression of the innate alarmin cytokine TSLP in a time-and dose-dependent manner. In vivo, the exposure to BPA through water supply or inhalation induced a systemic para-inflammatory response by promoting the expression of innate inflammatory mediators in the skin, gut, and airway. In a murine tolerogenic antigen challenge model, chronic systemic exposure to BPA was sufficient to induce airway sensitization to innocuous chicken egg ovalbumin in the complete absence of adjuvants. Mechanistic studies are needed to test conclusively whether endocrine disruptors may play an upstream role in allergic sensitization via their ability to promote a para-inflammatory state.