17-epiestriol, an estrogen metabolite, is more potent than estradiol in inhibiting vascular cell adhesion molecule 1 (VCAM-1) mRNA expression

Aging modulates homeostatic leukocyte trafficking to the peritoneal cavity in a sex-specific manner

Aging is associated with exacerbated systemic inflammation (inflammaging) and the progressive loss of immune system function (immunosenescence). Leukocyte migration is necessary for effective immunity; however, dysregulated trafficking of leukocytes into tissue contributes to inflammaging and the development of age-related inflammatory diseases. Aging modulates leukocyte trafficking under inflammatory conditions; however, whether aging modulates leukocyte trafficking under homeostatic conditions remains to be elucidated. Although immune responses are evidently sexually dimorphic, limited studies have investigated the effect of sex on age-related changes to leukocyte trafficking processes. Here, we investigated age-related and sex-specific changes to the leukocyte populations within the peritoneal cavity of young (3-mo), middle-aged (18-mo) and old (21-mo) male and female wild-type mice in the steady state. We found an age-related increase in the number of leukocytes within the peritoneal cavity of female mice, predominantly B cells, which may reflect increased trafficking through this tissue with age. This was accompanied by an increased inflammatory environment within the aged cavity, including increased levels of chemoattractants, including B cell chemoattractants CXCL13 and CCL21, soluble adhesion molecules, and proinflammatory cytokines, which was more pronounced in aged female mice. Intravital microscopy techniques revealed altered vascular structure and increased vascular permeability within the peritoneal membrane of aged female mice, which may support increased leukocyte trafficking to the cavity with age. Together, these data indicate that aging affects homeostatic leukocyte trafficking processes in a sex-specific fashion.

The effect of estrogen therapy on cerebral metabolism in diabetic female rats

The impact of estrogen on brain function, especially in individuals with diabetes, remains uncertain. This study aims to compare cerebral glucose metabolism levels in intact rats, ovariectomized (OVX) rats, and 17β-estradiol (E2)-treated OVX diabetic female rats. Sixteen rats were administered a single intraperitoneal injection of 70 mg/kg streptozotocin (STZ) to induce diabetes (intact, n = 6; OVX, n = 6; OVX+E2-treated, n = 4). Additionally, 18 rats received an equivalent solvent dose via intraperitoneal injection (intact, n = 6; OVX, n = 6; OVX+E2-treated, n = 6). After 4 weeks of STZ or solvent administration, positron emission tomography scans with 18F-fluorodeoxyglucose (18F-FDG) injection were employed to assess cerebral glucose metabolism. The diabetic rats exhibited substantial reductions in 18F-FDG uptake across all brain regions (all P < 0.01), in contrast to the control rats. Moreover, intact and OVX + E2-treated diabetic female rats displayed more pronounced decreases in cerebral glucose metabolism in the amygdala and hippocampus compared to OVX diabetic female rats (P < 0.05). These findings suggest that diabetes creates an environment wherein estrogen exacerbates neuropathology and intensifies neuronal activity.

Understanding the Phytoestrogen Genistein Actions on Breast Cancer: Insights on Estrogen Receptor Equivalence, Pleiotropic Essence and Emerging Paradigms in Bioavailability Modulation

Prevalent as a major phenolic ingredient of soy and soy products, genistein is recognized as an eminent phytoestrogen owing to its interacting ability with estrogen receptors (ERs). The metabolic conversion of plant-derived genistin to genistein by gut microbes and intestinal enzymes enhances its absorption at intestinal pH of ~7.5-7.8. Genistein interferes in breast cancer (BC) development via pleiotropic actions on cell proliferation, survival, angiogenesis, and apoptosis. Though multiple investigations have demonstrated genistein intake-driven reduced BC risk, similar efficacy has not been replicated in clinical trials. Furthermore, multiple studies have structurally and functionally equated genistein extents with 17-β-estradiol (E2), the most available physiological estrogen in females, culminating in aggravated BC growth. Of note, both genistein and E2 function via interacting with ERs (ERα and ERβ). However, although E2 shows almost equal affinity towards both ERα and ERβ, genistein shows more affinity towards ERβ than ERα. Our cautious literature survey revealed typical intake mode, ER expression pattern and the ratio of ERα and ERβ, transactivators/ regulators of ERα and ERβ expression and activities, patient age, and menopausal status as decisive factors affecting genistein BC activities. Of further interest are the mechanisms by which genistein inhibits triple-negative breast cancers (TNBCs), which lack ERs, progesterone receptors (PRs), and human epidermal growth factor receptors (HER2). Herein, we attempt to understand the dosage-specific genistein actions in BC cells and patients with an insight into its better response via derivative development, nanocarrier-assisted, and combinatorial delivery with chemotherapeutic drugs.

Inflammatory Basis of Atherosclerosis: Modulation by Sex Hormones

Atherosclerosis-related cardiovascular diseases (CVDs) are the leading cause of death globally. Several lines of evidence are supportive of the contributory role of vascular inflammation in atherosclerosis. Diverse immune cell types, including monocytes/macrophages, T-cells and neutrophils, as well as specialized proresolving lipid mediators, have been successfully characterized as key players in vascular inflammation. The increased prevalence of atherosclerotic CVD in men in comparison to age-matched premenopausal women and the abolition of sex differences in prevalence during menopause strongly suggest a pivotal role of sex hormones in the development of CVD. Indeed, many animal and human studies conclusively implicate sex hormones as a crucial component in driving the immune response. This is further corroborated by the effective identification of sex hormone receptors in vascular endothelial cells, vascular smooth muscle cells and immune cells. Collectively, these findings suggest a cellular communication between sex hormones and vascular or immune cells underlying the vascular inflammation in atherosclerosis. The aim of this review is to provide an overview of vascular inflammation as a causal cue underlying atherosclerotic CVDs within the context of the modulatory effects of sex hormones. Moreover, the cellular and molecular signaling pathways underlying the sex hormones- immune system interactions as potential culprits for vascular inflammation are highlighted with detailed and critical discussion. Finally, the review concludes by speculations on the potential sex-related efficacy of currently available immunotherapies in mitigating vascular inflammation. Conceivably, a deeper understanding of the immunoregulatory influence of sex hormones on vascular inflammation-mediated atherosclerosis permits sex-based management of atherosclerosis-related CVDs.

Febuxostat Attenuates the Induction of Vascular Cell Adhesion Protein 1 by TNF-α in Human Umbilical Vein Endothelial Cells

In a randomized trial, higher all-cause and cardiovascular mortality was observed in treatment with febuxostat than with allopurinol in patients with coexisting gout and serious cardiovascular conditions. In this study, we focus on an intervention of febuxostat or allopurinol as an anti-inflammatory treatment to reduce the transcription of nuclear factor-kappa B (NF-κB) and production of relevant inflammatory factors. We evaluated the effect of febuxostat on vascular cell adhesion protein 1 (VCAM-1) induction in cultured human umbilical vein endothelial cells (HUVECs). Cells were exposed to tumor necrosis factor (TNF)-α (10 ng/mL) treatment for 24 h. Febuxostat or allopurinol (0.1–100 μM) was added to the bath medium 15 min before TNF-α treatment. VCAM-1 levels in HUVECs increased after 24-h TNF-α treatment (<i>n</i> = 4). Febuxostat and allopurinol significantly suppressed VCAM-1 induced by treatment with TNF-α in a dose-dependent manner (<i>p</i> &#x3c; 0.05, <i>n</i> = 4). Furthermore, these drugs suppressed the NF-κB protein levels in the nucleus 4 h after TNF-α treatment (<i>n</i> = 3 or 4). Our results suggest that TNF-α induces VCAM-1 production via NF-κB, which can be blocked by febuxostat or allopurinol. The effect of febuxostat treatment on cardiovascular events may be associated with protection against the infiltration of lymphocytes or monocytes through VCAM-1 induction in inflamed endothelial cells such as arterial sclerosis.

MicroRNA-29a-3p Reduces TNFα-Induced Endothelial Dysfunction by Targeting Tumor Necrosis Factor Receptor 1

miR-29a-3p has been shown to be associated with cardiovascular diseases; however, the effect of miR-29a-3p on endothelial dysfunction is unclear. This study aimed to reveal the effects and mechanisms of miR-29a-3p on endothelial dysfunction. The levels of vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and E-selectin were determined by real-time PCR and immunofluorescence staining to reveal the degree of tumor necrosis factor alpha (TNFα)-induced endothelial dysfunction. A luciferase activity assay and cell transfection with a miR-29a-3p mimic or an inhibitor were used to reveal the underlying mechanisms of miR-29a-3p action. Furthermore, the effects of miR-29a-3p on endothelial dysfunction were assessed in C57BL/6 mice injected with TNFα and/or a miR-29a-3p agomir. The results showed that the expression of TNFα-induced adhesion molecules in vascular endothelial cells (EA.hy926 cells, human aortic endothelial cells [HAECs], and primary human umbilical vein endothelial cells [pHUVECs]) and smooth muscle cells (human umbilical vein smooth muscle cells [HUVSMCs]) was significantly decreased following transfection with miR-29a-3p. This effect was reversed by cotransfection with a miR-29a-3p inhibitor. As a key target of miR-29a-3p, tumor necrosis factor receptor 1 mediated the effect of miR-29a-3p. Moreover, miR-29a-3p decreased the plasma levels of TNFα-induced VCAM-1 (32.62%), ICAM-1 (38.22%), and E-selectin (39.32%) in vivo. These data indicate that miR-29a-3p plays a protective role in TNFα-induced endothelial dysfunction, suggesting that miR-29a-3p is a novel target for the prevention and treatment of atherosclerosis.

Associations between intake of dietary fermented soy food and concentrations of inflammatory markers: a cross-sectional study in Japanese workers

Epidemiological investigations have shown that consumption of soybeans or soy foods reduces the risk of the development of cardiovascular disease, cancer and osteoporosis. The aim of this study was to determine the associations between different soy foods and inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, and IL-18, in Japanese workers. The cross-sectional study included 1,426 Japanese workers (1,053 men and 373 women) aged 20 to 64 years. Intake of 12 soy foods was estimated by a validated food frequency questionnaire. Associations of total soy foods, fermented soy food, non-fermented soy food, soy isoflavone with hs-CRP, IL-6, and IL-18 levels were examined by general linear model regression analysis. We found that total fermented soy food intake was inversely associated with multivariable-adjusted geometric concentration of IL-6 in men (Q1:1.03 pg/mL, Q5:0.94 pg /mL;P for trend = 0.031). Furthermore, it was shown that IL-6 concentrations were inversely associated with miso intake (β = -0.068;p = 0.034) and soy sauce intake in men (β = -0.074;p = 0.018). This study suggests that intake of total fermented soy food, miso and soy sauce be associated with IL-6 concentrations in Japanese men. J. Med. Invest. 65:74-80, February, 2018.

ApoM Suppresses TNF-α-Induced Expression of ICAM-1 and VCAM-1 Through Inhibiting the Activity of NF-κB

To explore the anti-inflammatory effect of apolipoprotein M (apoM) on regulation of tumor necrosis factor-α (TNF-α)-induced expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and further investigate the molecular mechanism of apoM in this process. We found that TNF-α could decrease expression of apoM and inhibitor of NF-κB-α (IκBα) in HepG2 cells. Overexpression of apoM caused a significant decrease of ICAM-1 and VCAM-1 expression, while it caused a significant increase of IκBα expression in HepG2 cells. Furthermore, the treatment with TNF-α could increase ICAM-1 and VCAM-1 expression, decrease IκBα protein expression, and increase nuclear factor-κB (NF-κB) activity, and these effects were markedly enhanced by small interfering RNA (siRNA)-mediated silencing of apoM in HepG2 cells. Our findings demonstrated that apoM suppressed TNF-α-induced expression of ICAM-1 and VCAM-1 through inhibiting the activity of NF-κB.

Glatiramer acetate (GA) prevents TNF-α-induced monocyte adhesion to primary endothelial cells through interfering with the NF-κB pathway

Pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) is considered to be the major one contributing to the process of development of endothelial dysfunction. Exposure to TNF-α induces the expression of a number of proinflammatory chemokines, such as monocyte chemotactic protein-1 (MCP-1), and adhesion molecules, including vascular adhesion molecule-1 (VCAM-1) and E-selectin, which mediate the interaction of invading monocytes with vascular endothelial cells. Glatiramer acetate (GA) is a licensed clinical drug for treating patients suffering from multiple sclerosis (MS). The effects of GA in vascular disease have not shown before. In this study, we found that GA significantly inhibited TNF-α-induced binding of monocytes to endothelial cells. Mechanistically, we found that GA ameliorated the upregulation of MCP-1, VCAM-1, and E-selectin induced by TNF-α. Notably, this process is mediated by inhibiting the nuclear translocation and activation of NF-κB. Our results also indicate that GA pretreatment attenuates the up-regulation of COX-2 and iNOS. These data suggest that GA might have a potential benefit in therapeutic endothelial dysfunction related diseases.

Luteolin protects against vascular inflammation in mice and TNF-alpha-induced monocyte adhesion to endothelial cells via suppressing IΚBα/NF-κB signaling pathway

Vascular inflammation plays a significant role in the pathogenesis of atherosclerosis. Luteolin, a naturally occurring flavonoid present in many medicinal plants and some commonly consumed fruits and vegetables, has received wide attention for its potential to improve vascular function in vitro. However, its effect in vivo and the molecular mechanism of luteolin at physiological concentrations remain unclear. Here, we report that luteolin as low as 0.5 μM significantly inhibited tumor necrosis factor (TNF)-α-induced adhesion of monocytes to human EA.hy 926 endothelial cells, a key event in triggering vascular inflammation. Luteolin potently suppressed TNF-α-induced expression of the chemokine monocyte chemotactic protein-1 (MCP-1) and adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), key mediators involved in enhancing endothelial cell-monocyte interaction. Furthermore, luteolin inhibited TNF-α-induced nuclear factor (NF)-κB transcriptional activity, IκBα degradation, expression of IκB kinase β and subsequent NF-κB p65 nuclear translocation in endothelial cells, suggesting that luteolin can inhibit inflammation by suppressing NF-κB signaling. In an animal study, C57BL/6 mice were fed a diet containing 0% or 0.6% luteolin for 3 weeks, and luteolin supplementation greatly suppressed TNF-α-induced increase in circulating levels of MCP-1/JE, CXCL1/KC and sICAM-1 in C57BL/6 mice. Consistently, dietary intake of luteolin significantly reduced TNF-α-stimulated adhesion of monocytes to aortic endothelial cells ex vivo. Histology shows that luteolin treatment prevented the eruption of endothelial lining in the intima layer of the aorta and preserved elastin fibers' delicate organization as shown by Verhoeff-Van Gieson staining. Immunohistochemistry studies further show that luteolin treatment also reduced VCAM-1 and monocyte-derived F4/80-positive macrophages in the aorta of TNF-α-treated mice. In conclusion, luteolin protects against TNF-α-induced vascular inflammation in both in vitro and in vivo models. This anti-inflammatory effect of luteolin may be mediated via inhibition of the NF-κB-mediated pathway.

Relationship of Advanced Glycation End Products With Cardiovascular Disease in Menopausal Women

Cardiovascular disease (CVD) represents the most significant cause of death in postmenopausal women. Advanced glycation end products (AGEs) are formed by nonenzymatic modification of proteins, lipids, and nucleic acids by glucose. This review focuses on the contribution of AGEs and their receptors to the development of CVD in menopause. Advanced glycation end products circulate and activate the proinflammatory endothelial cell surface receptor called RAGE, bind to the extracellular matrix of the cardiovascular system, or bind to the circulating anti-inflammatory soluble form of RAGE (sRAGE). Data emerging from human and animal studies suggest that AGEs and both receptors (RAGE and sRAGE) are implicated in the pathophysiology of CVD. Particular emphasis has been given to the role of AGE-RAGE axis in oxidative stress, inflammation, endothelial cell toxicity, and progression of atherosclerosis in menopause. Data accruing from human and animal studies suggest that RAGE expression level and circulating sRAGE level are associated with estradiol and are correlated with CVD risk factors, such as adiposity, dyslipidemia, insulin resistance, diabetes, and metabolic syndrome. By recognizing the impact of AGEs on atherosclerosis, pharmacological strategies targeting the AGE-RAGE pathway hold therapeutic potential for CVD in menopausal women.

Sulforaphane reduces vascular inflammation in mice and prevents TNF-α-induced monocyte adhesion to primary endothelial cells through interfering with the NF-κB pathway

Sulforaphane, a naturally occurring isothiocyanate present in cruciferous vegetables, has received wide attention for its potential to improve vascular function in vitro. However, its effect in vivo and the molecular mechanism of sulforaphane at physiological concentrations remain unclear. Here, we report that a sulforaphane concentration as low as 0.5 μM significantly inhibited tumor necrosis factor-α (TNF-α)-induced adhesion of monocytes to human umbilical vein endothelial cells, a key event in the pathogenesis of atherosclerosis both in static and under flow conditions. Such physiological concentrations of sulforaphane also significantly suppressed TNF-α-induced production of monocyte chemotactic protein-1 and adhesion molecules including soluble vascular adhesion molecule-1 and soluble E-selectin, key mediators in the regulation of enhanced endothelial cell-monocyte interaction. Furthermore, sulforaphane inhibited TNF-α-induced nuclear factor (NF)-κB transcriptional activity, Inhibitor of NF-κB alpha (IκBα) degradation and subsequent NF-κB p65 nuclear translocation in endothelial cells, suggesting that sulforaphane can inhibit inflammation by suppressing NF-κB signaling. In an animal study, sulforaphane (300 ppm) in a mouse diet significantly abolished TNF-α-increased ex vivo monocyte adhesion and circulating adhesion molecules and chemokines in C57BL/6 mice. Histology showed that sulforaphane treatment significantly prevented the eruption of endothelial lining in the intima layer of the aorta and preserved elastin fibers' delicate organization, as shown by Verhoeff-van Gieson staining. Immunohistochemistry studies showed that sulforaphane treatment also reduced vascular adhesion molecule-1 and monocyte-derived F4/80-positive macrophages in the aorta of TNF-α-treated mice. In conclusion, sulforaphane at physiological concentrations protects against TNF-α-induced vascular endothelial inflammation, in both in vitro and in vivo models. This anti-inflammatory effect of sulforaphane may be, at least in part, associated with interfering with the NF-κB pathway.

Estrogen receptor α and β in the normal immune system and in lymphoid malignancies

Estrogens regulate various normal and pathophysiological processes including cancers. Cellular signaling by estrogens is mediated by estrogen receptor α (ERα) and β (ERβ), respectively. Binding of agonists to the ERs affects gene transcription. The main endogenous estrogen, 17β-estradiol (E2), binds to both ERα and ERβ with similar affinity. However, the ligand-binding pocket of ERα and ERβ are slightly different which has allowed the development of selective ER ligands. Importantly, while estrogens via ERα stimulate proliferation, signaling via ERβ inhibits proliferation and promotes apoptosis. In both normal and cancer cells the ERs are co-expressed with ER splice variants which may modify the transcriptional activity of the wild-type receptors. Estrogens have prominent effects on immune functions and both ERα and ERβ are expressed in immune cells and lymphoid malignancies. With regard to lymphoid malignancies, most show estrogen influence as several epidemiological studies of lymphoid cancers demonstrate gender differences in incidence and prognosis with males being more affected. In line with these findings, recent results generated by us have shown that ERβ selective agonists inhibit growth and induce apoptosis in human and murine lymphomas in vivo in xenograft experiments. This suggests that ERβ selective agonists in the future may be useful in the treatment of lymphomas.

Estrogen sulfotransferase (SULT1E1) regulates inflammatory response and lipid metabolism of human endothelial cells via PPARγ

Estrogen sulfotransferase (SULT1E1) is a phase II drug-metabolizing enzyme known to catalyze sulfoconjugation of estrogens. 17β-estradiol (E2) plays a pivotal role in attenuating endothelial dysfunction. E2 can be further sulfated to estradiol sulfate (E2S) using SULT1E1. To date, there are no reports of expression and function of SULT1E1 in the endothelium. We identified that SULT1E1 is highly expressed in human umbilical vein endothelial cells (HUVECs) using immunofluorescence microscopy and Western immunoblot analyses. A synthesized siRNA targeting SULT1E1 was used to successfully suppress SULT1E1 expression and inhibit estrogen sulfation in HUVECs. This led to functional depletion, as confirmed by a SULT1E1 enzyme activity assay in vitro and by an in vivo estrogen sulfation assay. Knock-down of SULT1E1 in HUVECs resulted in regulation of genes involved in inflammation and lipid metabolism. Interestingly, this regulation was attenuated by PPARγ siRNA and by exposure to the PPARγ antagonist GW9662. Compared with cell response in the absence of estrogen, the effects of SULT1E1 interference on the inflammatory response and lipid metabolism related genes in the presence of 80nM estrogen were completely opposite. When exogenous estrogen was applied, cell responses depended on the ratio of E2 to E2S, due to the activity of SULT1E1, and the different regulation of these processes. It is suggested that E2 sulfation catalyzed by SULT1E1 plays an important role in modulating endothelial cell function.

Aberrant synthesis, metabolism, and plasma accumulation of circulating estrogens and estrogen metabolites in preeclampsia implications for vascular dysfunction

Estrogens and estrogen metabolites have important functions in cardiovascular and other physiology, yet the patterns of estrogen synthesis, metabolism, and the individual plasma profile of estrogens and estrogen metabolites during human pregnancy as well as in preeclampsia remain undetermined. We performed liquid chromatography mass spectrometry on plasma samples from normotensive pregnant women (normP; n=8), women with mild (mPE; n=8), and severe (sPE; n = 8) preeclampsia at labor. Compared with normP, estrone was lower in sPE, whereas plasma level of estradiol-17β was significantly lower in women with mPE and sPE. Estriol was lower in sPE, but not in mPE. Although 2-hydroxyestrone was lower in mPE and sPE, 4-hydroxyestrone was high in sPE. 16-α-hydroxyestrone was higher in mPE, but not in sPE. 2-hydroxyestradiol in women with mPE and sPE were lower compared with normP. Compared with 2-methoxyestrone in normP, levels were lower in sPE. 3-methoxyestrone and 4-methoxyestrone were unchanged. 2-methoxyestradiol was lower in mPE and sPE; however, 4-methoxyestradiol was low only in sPE. Compared with normP, 16-keto-estradiol-17β levels were significantly higher in sPE, whereas 16-epi-estriol and 17-epi-estriol were lower in women with sPE. Our findings show that preeclampsia is characterized by aberrant synthesis, metabolism, and accumulation of estrogens and estrogen metabolites that are likely to be associated with alterations in vascular function. These results underscore the need to investigate the functional vascular and other physiology of estrogens and estrogen metabolites in the pathophysiology of preeclampsia.

Soy food intake and circulating levels of inflammatory markers in Chinese women

BACKGROUND

Soy and some of its constituents, such as isoflavones, have been shown to affect the inflammatory process in animal studies. The association between soy food intake and inflammatory markers has not been evaluated adequately in humans.

OBJECTIVE

Our aim was to evaluate whether higher intake of soy foods was inversely associated with inflammatory markers in 1,005 middle-aged Chinese women.

DESIGN

In this cross-sectional study, dietary intake of soy foods was assessed by a validated food frequency questionnaire and by a 24-hour recall when biospecimens were procured. A general linear model was used to estimate the geometric means of selected inflammatory markers, including interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNFα), soluble IL-6 receptor, soluble GP130, soluble TNF receptors 1 and 2, and C-reactive protein, across categories of soy food intake after adjusting for age, lifestyle and dietary factors, and history of infectious or inflammation-related diseases.

RESULTS

We found that multivariable-adjusted geometric mean concentrations of IL-6 and TNFα were inversely associated with quintiles of soy food intake, with a difference between the highest and lowest quintiles of 25.5% for IL-6 (P for trend=0.008) and 14% for TNFα (P for trend=0.04). Similar inverse associations were found for TNFα (P for trend=0.003), soluble TNF receptor 1 (P for trend=0.01), soluble TNF receptor 2 (P for trend=0.02), IL-1β (P for trend=0.05), and IL-6 (P for trend=0.04) when soy food consumption was assessed by the frequency of consumption in the preceding 24 hours. No significant associations were found for other markers studied.

CONCLUSIONS

This study suggests that soy food consumption is related to lower circulating levels of IL-6, TNFα, and soluble TNF receptors 1 and 2 in Chinese women.

Estrogens and atherosclerosis: insights from animal models and cell systems

Estrogens not only play a pivotal role in sexual development but are also involved in several physiological processes in various tissues including vasculature. While several epidemiological studies documented an inverse relationship between plasma estrogen levels and the incidence of cardiovascular disease and related it to the inhibition of atherosclerosis, an interventional trial showed an increase in cardiovascular events among postmenopausal women on estrogen treatment. The development of atherosclerotic lesions involves complex interplay between various pro- or anti-atherogenic processes that can be effectively studied only in vivo in appropriate animal models. With the advent of genetic engineering, transgenic mouse models of atherosclerosis have supplemented classical dietary cholesterol-induced disease models such as the cholesterol-fed rabbit. In the last two decades, these models were widely applied along with in vitro cell systems to specifically investigate the influence of estrogens on the development of early and advanced atherosclerotic lesions. The present review summarizes the results of these studies and assesses their contribution toward better understanding of molecular mechanisms underlying anti- and/or pro-atherogenic effects of estrogens in humans.

Effects of 17 β-estradiol on lipopolysacharride-induced intracellular adhesion molecule-1 mRNA expression and Ca²+ homeostasis alteration in human endothelial cells

Recent evidence showed that 17 β-estradiol (E₂) decreased cytokine-induced expression of cell adhesion molecules (CAM). Changes in intracellular Ca²+ concentration ([Ca²+](i)) has been shown to be associated with CAM expression in endothelial cells. Here, the effects of E₂ (1 μM, 24 h) on the expression of intracellular adhesion molecule-1 (ICAM-1) and [Ca²+](i) were investigated in a lipopolysaccharide (LPS) (100 ng/mL, 18 h)-stimulated human endothelial cell line, EA.hy926, using real-time PCR and spectrofluorometry, respectively. PCR analysis revealed a significant increase in ICAM-1 expression in calcium ionophore A23187 (1 nM)- or LPS-stimulated cells. Pretreatment of cells with E(2) significantly inhibited LPS-induced ICAM-1 mRNA expression. [Ca²+](i) was monitored in Fura-2AM-loaded cells in the presence and absence of extracellular Ca²+ with thapsigargin (TG, 1 μM), a sarco/endoplasmic reticulum ATPase inhibitor or ATP (100 μM). The extent of TG- or ATP-induced [Ca²+](i) increase was significantly higher in LPS-stimulated cells than in control cells. Pre-treatment of LPS-stimulated cells with E₂ limited the Ca²+ response to the same level as in control cells. Furthermore, ICI 182,780, an estrogen receptor antagonist, attenuated the inhibitory actions of E₂ on ICAM-1 mRNA expression and Ca²+ responses, suggesting that estrogen receptors mediate, at least in part, the effects of estrogen. These data suggest a potential underlying mechanism for the protective effect of E₂ against atherosclerosis.

Atherosclerosis and sex hormones: current concepts

CVD (cardiovascular disease) is the leading cause of death for women. Considerable progress has been made in both our understanding of the complexities governing menopausal hormone therapy and our understanding of the cellular and molecular mechanisms underlying hormone and hormone receptor function. Understanding the interplay of atherosclerosis and sex steroid hormones and their cognate receptors at the level of the vessel wall has important ramifications for clinical practice. In the present review, we discuss the epidemiology of CVD in men and women, the clinical impact of sex hormones on CVD, and summarize our current understanding of the pathogenesis of atherosclerosis with a focus on gender differences in CVD, its clinical presentation and course, and pathobiology. The critical animal and human data that pertain to the role of oestrogens, androgens and progestins on the vessel wall is also reviewed, with particular attention to the actions of sex hormones on each of the three key cell types involved in atherogenesis: the endothelium, smooth muscle cells and macrophages. Where relevant, the systemic (metabolic) effects of sex hormones that influence atherogenesis, such as those involving vascular reactivity, inflammation and lipoprotein metabolism, are discussed. In addition, four key current concepts in the field are explored: (i) total hormone exposure time and coronary heart disease risk; (ii) the importance of tissue specificity of sex steroid hormones, critical timing and the stage of atherosclerosis in hormone action; (iii) biomarkers for atherosclerosis with regard to hormone therapy; and (iv) the complex role of sex steroids in inflammation. Future studies in this field will contribute to guiding clinical treatment recommendations for women and help define research priorities.

The soyabean isoflavone genistein modulates endothelial cell behaviour

The aim of the present study was to investigate the direct action of the phyto-oestrogen genistein (Gen) on vascular endothelial behaviour, either in the presence or absence of proinflammatory agents. In rat aortic endothelial cell (EC) cultures, 24 h of treatment with Gen significantly increased cell proliferation in a wide range of concentration (0.001-10 nm). This mitogenic action was prevented by the oestrogen receptor (ER) antagonist ICI 182780 or by the presence of the specific NO synthase inhibitor l-nitro-arginine methyl ester. When monocytes adhesion to EC was measured, Gen partially attenuated leucocyte adhesion not only under basal conditions, but also in the presence of bacterial lipopolysaccharides (LPS). The effect of the phyto-oestrogen on the expression of EC adhesion molecules was evaluated. Gen down-regulated the enhancement in mRNA levels of E-selectin, vascular cell adhesion molecule-1 and P-selectin elicited by the proinflammatory agent bacterial LPS. The regulation of EC programmed death induced by the isoflavone was also demonstrated. Incubation with 10 nm Gen prevented DNA fragmentation induced by the apoptosis inductor H2O2. The results presented suggest that Gen would exert a protective effect on vascular endothelium, due to its regulatory action on endothelial proliferation, apoptosis and leucocyte adhesion, events that play a critical role in vascular diseases. The molecular mechanism displayed by the phyto-oestrogen involved the participation of the ER and the activation of the NO pathway.

Role of estrogen receptors in pro-oxidative and anti-oxidative actions of estrogens: a perspective

BACKGROUND

Estrogens are steroid hormones responsible for the primary and secondary sexual characteristics in females. While pre-menopausal women use estrogens as the main constituents of contraceptive pills, post-menopausal women use the same for Hormone Replacement Therapy. Estrogens produce reactive oxygen species by increasing mitochondrial activity and redox cycling of estrogen metabolites. The phenolic hydroxyl group present at the C3 position of the A ring of estrogens can get oxidized either by accepting an electron or by losing a proton. Thus, estrogens might act as pro-oxidant in some settings, resulting in complicated non-communicable diseases, namely, cancer and cardiovascular disorders. However, in some other settings the phenolic hydroxyl group of estrogens may be responsible for the anti-oxidative beneficial functions and thus protect against cardiovascular and neurodegenerative diseases.

SCOPE OF REVIEW

To date, no single review article has mentioned the implication of estrogen receptors in both the pro-oxidative and anti-oxidative actions of estrogens.

MAJOR CONCLUSION

The controversial role of estrogens as pro-oxidant or anti-oxidant is largely dependent on cell types, ratio of different types of estrogen receptors present in a particular cell and context specificity of the estrogen hormone responses. Both pro-oxidant and anti-oxidant effects of estrogens might involve different estrogen receptors that can have either genomic or non-genomic action to manifest further hormonal response.

GENERAL SIGNIFICANCE

This review highlights the role of estrogen receptors in the pro-oxidative and anti-oxidative actions of estrogens with special emphasis on neuronal cells.

Analytical and compositional aspects of isoflavones in food and their biological effects

This paper provides an overview of analytical techniques used to determine isoflavones (IFs) in foods and biological fluids with main emphasis on sample preparation methods. Factors influencing the content of IFs in food including processing and natural variability are summarized and an insight into IF databases is given. Comparisons of dietary intake of IFs in Asian and Western populations, in special subgroups like vegetarians, vegans, and infants are made and our knowledge on their absorption, distribution, metabolism, and excretion by the human body is presented. The influences of the gut microflora, age, gender, background diet, food matrix, and the chemical nature of the IFs on the metabolism of IFs are described. Potential mechanisms by which IFs may exert their actions are reviewed, and genetic polymorphism as determinants of biological response to soy IFs is discussed. The effects of IFs on a range of health outcomes including atherosclerosis, breast, intestinal, and prostate cancers, menopausal symptoms, bone health, and cognition are reviewed on the basis of the available in vitro, in vivo animal and human data.

Gender and sex hormones in multiple sclerosis pathology and therapy

Several lines of evidence indicate that gender affects the susceptibility and course of multiple sclerosis (MS) with a higher disease prevalence and overall better prognosis in women than men. This sex dimorphism may be explained by sex chromosome effects and effects of sex steroid hormones on the immune system, blood brain barrier or parenchymal central nervous system (CNS) cells. The well known improvement in disease during late pregnancy has also been linked to hormonal changes and has stimulated recent clinical studies to determine the efficacy of and tolerance to sex steroid therapeutic approaches. Both clinical and experimental studies indicate that sex steroid supplementation may be beneficial for MS. This could be related to anti-inflammatory actions on the immune system or CNS and to direct neuroprotective properties. Here, clinical and experimental data are reviewed with respect to the effects of sex hormones or gender in the pathology or therapy of MS or its rodent disease models. The different cellular targets as well as some molecular mechanisms likely involved are discussed.

Genistein inhibits the development of atherosclerosis via inhibiting NF-κB and VCAM-1 expression in LDLR knockout mice

Diet can be an important factor that influences risks for cardiovascular disease. Genistein (4′,5,7-trihydroxyisoflavone), rich in soy, is one candidate that may benefit the cardiovascular system. Here, we explored the effect of genistein in atherosclerosis (AS) development in an in vivo mouse model. Low-density lipoprotein receptor (LDLR) knockout mice were allocated to control, model, and genistein groups. Our results showed that genistein significantly reduced the formation and development of atherosclerotic plaques ((4.68 ± 1.18) ×106 versus (6.65 ± 1.51) ×106 µm2, p < 0.05). In the genistein group, compared with the model group, total antioxidant capacity (TAC) level was 85.5 ± 15.6 versus 203.4 ± 32.6 mmol/L (p < 0.01); malondialdehyde (MDA) level was 3.79 ± 0.28 versus 3.06 ± 0.31 mmol/L (p < 0.01), and superoxide dismutase (SOD) activity was 86.1 ± 6.1 versus 139.1 ± 25.1 U/mL (p < 0.01). Therefore, genistein was able to enhance serum antioxidative ability in our mouse model. Genistein had no influence, however, on serum cholesterol and lipid profiles. Genistein also markedly downregulated the expression of nuclear factor (NF)-κB and vascular cell adhesion molecule (VCAM)-1 in aortas of mice (p < 0.05). These observations suggest that genistein may inhibit AS in LDLR−/− mice via enhancing serum antioxidation and downregulating NF-κB and VCAM-1 expression in the aorta.

Serum levels of soluble vascular cell adhesion molecule-1, tumor necrosis factor-alpha, and interleukin-6 in in vitro fertilization cycles

OBJECTIVE

To assess whether gonadotropin-induced changes in E(2) alter serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) and proinflammatory cytokines.

DESIGN

Prospective collection of serum in patients undergoing IVF.

SETTING

University hospital.

PATIENT(S)

Twenty-four infertile women.

INTERVENTION(S)

Serum collection at baseline, in the mid and late follicular phases, at oocyte retrieval, and in the mid and late luteal phases.

MAIN OUTCOME MEASURE(S)

Samples were assayed for sVCAM-1, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and E(2).

RESULT(S)

The VCAM-1 was maximally suppressed in the luteal phase. Luteal sVCAM-1 levels correlated [1] positively with the patient's age, units of gonadotropins, day 3 FSH levels and [2] negatively with [a] the follicular, retrieval, and luteal E(2) levels and [b] the number of preovulatory follicles and oocytes retrieved. Similar correlations were noted in the late luteal phase. Serum TNF-alpha reached a peak in the mid-follicular phase and a nadir in the luteal phase. The TNF-alpha levels at retrieval correlated [1] positively with the patient's age and [2] negatively with E(2) and number of preovulatory follicles and retrieved oocytes. The IL-6 levels were suppressed in the follicular phase and correlated negatively with E(2) levels.

CONCLUSION(S)

Changes in E(2) levels seen during gonadotropin stimulation significantly alter VCAM-1 expression and induce changes in serum IL-6 and TNF-alpha levels.

Inflammatory status influences aromatase and steroid receptor expression in endometriosis

Aberrant up-regulation of aromatase in eutopic endometrium and implants from women with endometriosis has been reported. Aromatase induction may be mediated by increased cyclooxygenase-2 (COX-2). Recently, we demonstrated that progesterone receptor (PR)-A and PR-B serve an antiinflammatory role in the uterus by antagonizing nuclear factor kappaB activation and COX-2 expression. PR-C, which antagonizes PR-B, is up-regulated by inflammation. Although estrogen receptor alpha (ERalpha) is implicated in endometriosis, an antiinflammatory role of ERbeta has been suggested. We examined stage-specific expression of aromatase, COX-2, ER, and PR isoform expression in eutopic endometrium, implants, peritoneum, and endometrioma samples from endometriosis patients. Endometrial and peritoneal biopsies were obtained from unaffected women and those with fibroids. Aromatase expression in eutopic endometrium from endometriosis patients was significantly increased compared with controls. Aromatase expression in endometriosis implants was markedly increased compared with eutopic endometrium. Aromatase mRNA levels were increased significantly in red implants relative to black implants and endometrioma cyst capsule. Moreover, COX-2 expression was increased in implants and in eutopic endometrium of women with endometriosis as compared with control endometrium. As observed for aromatase mRNA, the highest levels of COX-2 mRNA were found in red implants. The ratio of ERbeta/ERalpha mRNA was significantly elevated in endometriomas compared with endometriosis implants and eutopic endometrium. Expression of PR-C mRNA relative to PR-A and PR-B mRNA was significantly increased in endometriomas compared with eutopic and control endometrium. PR-A protein was barely detectable in endometriomas. Thus, whereas PR-C may enhance disease progression, up-regulation of ERbeta may play an antiinflammatory and opposing role.

Isoflavones and endothelial function

Dietary isoflavones are thought to be cardioprotective due to their structural similarity to oestrogen. Oestrogen is believed to have beneficial effects on endothelial function and may be one of the mechanisms by which premenopausal women are protected against CVD. Decreased NO production and endothelial NO synthase activity, and increased endothelin-1 concentrations, impaired lipoprotein metabolism and increased circulating inflammatory factors result from oestrogen deficiency. Oestrogen acts by binding to oestrogen receptors α and β. Isoflavones have been shown to bind with greater affinity to the latter. Oestrogen replacement therapy is no longer thought to be a safe treatment for prevention of CVD; isoflavones are a possible alternative. Limited evidence from human intervention studies suggests that isoflavones may improve endothelial function, but the available data are not conclusive. Animal studies provide stronger support for a role of isoflavones in the vasculature, with increased vasodilation and endothelial NO synthase activity demonstrated. Cellular mechanisms underlying the effects of isoflavones on endothelial cell function are not yet clear. Possible oestrogen receptor-mediated pathways include modulation of gene transcription, and also non-genomic oestrogen receptor-mediated signalling pathways. Putative non-oestrogenic pathways include inhibition of reactive oxygen species production and up regulation of the protein kinase A pathway (increasing NO bioavailability). Further research is needed to unravel effects of isoflavones on intracellular regulation of the endothelial function. Moreover, there is an urgent need for adequately powered, robustly designed human intervention studies in order to clarify the present equivocal findings.

The complex role of estrogens in inflammation

There is still an unresolved paradox with respect to the immunomodulating role of estrogens. On one side, we recognize inhibition of bone resorption and suppression of inflammation in several animal models of chronic inflammatory diseases. On the other hand, we realize the immunosupportive role of estrogens in trauma/sepsis and the proinflammatory effects in some chronic autoimmune diseases in humans. This review examines possible causes for this paradox. This review delineates how the effects of estrogens are dependent on criteria such as: 1) the immune stimulus (foreign antigens or autoantigens) and subsequent antigen-specific immune responses (e.g., T cell inhibited by estrogens vs. activation of B cell); 2) the cell types involved during different phases of the disease; 3) the target organ with its specific microenvironment; 4) timing of 17beta-estradiol administration in relation to the disease course (and the reproductive status of a woman); 5) the concentration of estrogens; 6) the variability in expression of estrogen receptor alpha and beta depending on the microenvironment and the cell type; and 7) intracellular metabolism of estrogens leading to important biologically active metabolites with quite different anti- and proinflammatory function. Also mentioned are systemic supersystems such as the hypothalamic-pituitary-adrenal axis, the sensory nervous system, and the sympathetic nervous system and how they are influenced by estrogens. This review reinforces the concept that estrogens have antiinflammatory but also proinflammatory roles depending on above-mentioned criteria. It also explains that a uniform concept as to the action of estrogens cannot be found for all inflammatory diseases due to the enormous variable responses of immune and repair systems.

Dietary isoflavones in the prevention of cardiovascular disease--a molecular perspective

The Food and Drugs Administration has approved a health claim for soy based on clinical trials and epidemiological data indicating that high soy consumption is associated with a lower risk of coronary artery disease. Soy products contain a group of compounds called isoflavones, with genistein and daidzein being the most abundant. A number of cardioprotective benefits have been attributed to dietary isoflavones including a reduction in LDL cholesterol, an inhibition of pro-inflammatory cytokines, cell adhesion proteins and inducible nitric oxide production, potential reduction in the susceptibility of the LDL particle to oxidation, inhibition of platelet aggregation and an improvement in vascular reactivity. There is increasing interest in the use of nutrigenomic methods to understand the mechanisms by which isoflavones induce these changes, and in the use of nutrigenetics to understand why the effects vary between individuals. Nutrigenomics is a rapidly growing field making use of molecular biology methodologies, such as microarray technology and proteomics, to study how specific nutrients or diets affect gene expression and cellular protein levels. The analysis of differential gene expression and protein levels in endothelial cells, macrophages and smooth muscle cells is critical to elucidating the sequence of events leading to the formation of atherosclerotic lesions, and to understanding the potential anti-atherogenic properties of soy isoflavones. An increasing number of studies demonstrate a significant impact of genetic variation on changes in cardiovascular risk factors in response to dietary intervention. Nutrigenetic effects of this type have recently been reported for dietary isoflavones, and may help to explain some of the disparities in the current literature concerning isoflavones and cardiovascular health.

Castration of male C57L/J mice increases susceptibility and estrogen treatment restores resistance to Theiler's virus-induced demyelinating disease

Intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) results in immune-mediated demyelination in selective mouse strains. We have previously demonstrated that the males of C57L mice are significantly more susceptible to TMEV-induced demyelinating disease. To assess further the hormonal influence for this gender-associated differential susceptibility, estrogen-treated, castrated C57L mice were infected with TMEV and compared with sham-operated and/or placebo-treated mice. Interestingly, castration further elevated the susceptibility to virally induced demyelinating disease compared with sham-castrated control mice, and prolonged treatment of castrated mice with estrogen restored the resistance to the level of control mice. These results strongly suggest that sex hormone levels contribute to the gender-biased susceptibility to TMEV-induced demyelinating disease. Mice treated with estrogen showed a significantly decreased level of virus-specific Th1 responses both in the periphery and in the CNS. In addition, in vitro estrogen treatment was able to inhibit viral replication directly in macrophages, consistent with the lower level of viral RNA in microglia/macrophages in the CNS from castrated estrogen-treated mice compared with controls. Also, estrogen treatment inhibited VCAM-1 expression induced by tumor necrosis factor-alpha in cerebral vascular endothelial (CVE) cells via inhibition of nuclear factor-kappaB (NFkappaB), which is produced in various glial cells upon TMEV infection. Overall, estrogen treatment appears to exert its effects on viral replication, induction of immune responses, as well as infiltration of activated immune cells into the CNS via inhibition of NFkappaB function.

High Concentration of Antioxidants N-Acetylcysteine and Mitoquinone-Q Induces Intercellular Adhesion Molecule 1 and Oxidative Stress by Increasing Intracellular Glutathione

In endothelial cells, the intracellular level of glutathione is depleted during offering protection against proinflammatory cytokine TNF-alpha-induced oxidative stress. Administration of anti-inflammatory drugs, i.e., N-acetylcysteine (NAC) or mitoquinone-Q (mito-Q) in low concentrations in the human pulmonary aortic endothelial cells offered protection against depletion of reduced glutathione and oxidative stress mediated by TNF-alpha. However, this study addressed that administration of NAC or mito-Q in high concentrations resulted in a biphasic response by initiating an enhanced generation of both reduced glutathione and oxidized glutathione and enhanced production of reactive oxygen species, along with carbonylation and glutathionylation of the cellular proteins. This study further addressed that IkappaB kinase (IKK), a phosphorylation-dependent regulator of NF-kappaB, plays an important regulatory role in the TNF-alpha-mediated induction of the inflammatory cell surface molecule ICAM-1. Of the two catalytic subunits of IKK (IKKalpha and IKKbeta), low concentrations of NAC and mito-Q activated IKKalpha activity, thereby inhibiting the downstream NF-kappaB and ICAM-1 induction by TNF-alpha. High concentrations of NAC and mito-Q instead caused glutathionylation of IKKalpha, thereby inhibiting its activity that in turn enhanced the downstream NF-kappaB activation and ICAM-1 expression by TNF-alpha. Thus, establishing IKKalpha as an anti-inflammatory molecule in endothelial cells is another focus of this study. This is the first report that describes a stressful situation in the endothelial cells created by excess of antioxidative and anti-inflammatory agents NAC and mito-Q, resulting in the generation of reactive oxygen species, carbonylation and glutathionylation of cellular proteins, inhibition of IKKalpha activity, and up-regulation of ICAM-1expression.

The dietary soy flavonoid genistein abrogates tissue factor induction in endothelial cells induced by the atherogenic oxidized phospholipid oxPAPC

INTRODUCTION

Tissue factor (TF) plays a pivotal role in the generation of thrombin in atherothrombotic disease. The oxidized phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (oxPAPC), an active compound of minimally oxidized low-density lipoprotein (MM-LDL), induces TF in endothelial cells (EC). The dietary soybean isoflavonoid genistein has been claimed to reverse several processes leading to atherosclerosis and related cardiovascular events via binding to estrogen receptors, generating nitric oxide (NO) or inhibiting tyrosine kinase-dependent pathways.

METHODS AND MATERIALS

The effects and mechanisms of genistein on activity, antigen expression and mRNA levels of oxPAPC-induced TF were studied in human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC).

RESULTS AND CONCLUSIONS

Genistein abrogated oxPAPC-induced TF activity in arterial and venous human EC to basal levels, as measured by functional clotting assay, and downregulated oxPAPC-induced antigen expression measured by flow cytometry and mRNA levels quantified by real-time PCR. Western blotting and inhibitor experiments with the estrogen-receptor inhibitor ICI 182,780 and the NO-synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) showed that the effect may be mediated via inhibition of phosphorylation of ERK, but not upstream MEK1/2. The effect is not mediated by the tyrosine kinase inhibitor activity of genistein, as another tyrosine kinase inhibitor (tyrphostin 25) had no effect. Binding to the estrogen receptor or generation of NO are not involved in the action of genistein on TF. In conclusion genistein reduces oxPAPC-induced TF expression and thereby the prothrombotic phenotype of EC, further substantiating and explaining the beneficial effects of dietary genistein in preventing atherosclerosis and related cardiovascular events.

The pathway-selective estrogen receptor ligand WAY-169916 displays differential activity in ischemia-reperfusion injury models

We previously reported on the development of a pathway-selective estrogen receptor (ER) ligand, WAY-169916, that has ER-dependent antiinflammatory activity and is devoid of classic ER transcriptional activity. In the current study, WAY-169916 and 17beta-estradiol (17beta-E2) were evaluated for protective activity in models of cardiac ischemia-reperfusion injury. In rats subjected to cardiac ischemia-reperfusion injury by occlusion of the left coronary artery, infarct size relative to the area at risk in the left ventricle was significantly attenuated by a single dose of 17beta-E2 (20 microg/kg, SC), and WAY-169916 administered SC (10 mg/kg) or IV (1 mg/kg) during the ischemia phase. In isolated hearts perfused on a Langendorff apparatus and subjected to global ischemia and reperfusion, 17beta-E2 and WAY-169916 both had direct cardioprotective activity when perfused at 1 microM but their effects varied between different end points. Perfusion with 17beta-E2 only improved recovery of left ventricle-developed pressure. Perfusion with WAY-169916 attenuated the elevation in perfusion pressure, diastolic pressure, and release of creatine kinase after ischemia. In contrast to 17alpha-ethinylestradiol, WAY-169916 had no classic estrogen effects on uterine weight or total serum cholesterol in rats treated for 4 days. The data demonstrate that the pathway-selective ER ligand WAY-169916 displays differential activity in vivo on different cardiovascular end points.

Modulating role of estradiol on arginase II expression in hyperlipidemic rabbits as an atheroprotective mechanism

We evaluated the effects of a 0.5% cholesterol-enriched diet (HCD) on nitric-oxide synthase (NOS) and arginase expression and the modulating role of 17beta-estradiol (E(2)) on this phenomenon. Thirty oopherectomized rabbits were divided into three groups and treated for 15 weeks. Group I received normal chow; group II, HCD; and group III, HCD plus E(2) pellets. Animals in group II showed an increase in plasma lipids, and they demonstrated atheromatous lesions as well as expression of arginase I and II accompanied by a significant number of BrdU-positive cells in endothelial cells and intimal muscle cells, suggestive of an increase in cellular proliferation. There was significant expression of inducible NOS and increased staining of nitrotyrosine-positive areas. These were not observed in group I animals. In both groups, E(2) levels were low. In group III animals, E(2) supplementation led to a decrease in atheromatous lesions and BrdU-positive cells and reduced expression of both inducible NOS and arginase I and II accompanied by a decrease in nitrotyrosine staining. E(2) levels were increased. Our results suggest that E(2) was responsible for these effects, despite the animals being hyperlipidemic, similar to those in group II. Because arginase is responsible for cell proliferation by converting l-arginine to polyamines, our results indicate that expression of arginase may play an important role in cellular proliferation in atherosclerosis, and inhibition of arginase expression by E(2) may be another potential mechanism in attenuating atherogenesis.

Synthesis and activity of a new class of pathway-selective estrogen receptor ligands: Hydroxybenzoyl-3,4-dihydroquinoxalin-2(1H)-ones

The anti-inflammatory activity of non-selective estrogens has been attributed to their ability to antagonize the activity of nuclear factor kappaB (NF-kappaB), a known mediator of inflammatory responses. Here we report the identification of a potent new class of pathway-selective ER ligands that selectively antagonize NF-kappaB functional activity, while exhibiting a lack of classical estrogenic effect.

Suppression of Extravillous Trophoblast Invasion of Uterine Spiral Arteries by Estrogen During Early Baboon Pregnancy

The present study determined whether estrogen plays a role in regulating invasion and remodeling of the uterine spiral arteries by extravillous trophoblasts during early baboon pregnancy. The level of trophoblast invasion of spiral arteries was assessed on day 60 of gestation (term is 184 days) in baboons untreated or treated on days 25-59 with estradiol or aromatizable androstenedione. The administration of estradiol or androstenedione increased (P<0.01) maternal serum estradiol levels approximately 3-fold above normal. The mean+/-SE percentage of spiral arteries/arterioles invaded by extravillous cytotrophoblasts in estradiol-treated baboons for vessels with diameters of 26-50 microm (0.0+/-0.0), 51-100 microm (1.2+/-0.7) and >100 microm (13.2+/-5.5) was 100%, 90%, and 75% lower (P<0.001), respectively, than in untreated baboons (2.4+/-1.2%; 11.0+/-5.5%, and 54.5+/-8.5%, respectively). Similar results were obtained with androstenedione treatment. However, the distribution of uterine spiral arteries grouped by diameter or number of arteries per basal plate area, i.e. microvessel density, were similar in untreated and estrogen-treated baboons. We suggest, therefore, that the low levels of estrogen exhibited during early primate pregnancy are required to permit normal progression of trophoblast vascular invasion and that the surge in estrogen which occurs during the second-third of normal pregnancy has a physiological role in suppressing further arterial trophoblast invasion. Consequently, we propose that the estrogen-dependent restraint of spiral artery invasion/remodeling ensures optimal blood flow dynamics across the uteroplacental vascular bed to promote normal fetal growth and development.

Serum levels of soluble vascular cell adhesion molecule-1 are decreased in women receiving oral contraceptives compared with normally menstruating women: implications in atherosclerosis

OBJECTIVE

The primary objective was to assess whether short-term changes in estradiol (E2), such as those observed in the menstrual cycle, alter serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), and whether VCAM-1 expression is suppressed in long-term users of exogenous estrogens. The secondary objective was to assess the association, if any, between inflammatory cytokines and expression of sVCAM-1.

DESIGN

Prospective collection of serum samples in healthy volunteers.

SETTING

University hospital.

PATIENTS(S)

Thirty-one normally menstruating women and 37 oral contraceptive (OC) users. Interventions included serum collection in the early follicular, late follicular, and midluteal phases of the menstrual cycle and once in oral contraceptive users.

MAIN OUTCOME MEASURE(S)

Samples were assayed for sVCAM-1, tumor necrosis factor alpha (TNF-alpha), and interleukin (IL)-6 by enzyme-linked immunoabsorbent assay (ELISA). Estradiol (E2) was measured by radioimmunoassay (RIA).

RESULT(S)

Oral contraceptive users had significantly lower serum levels of sVCAM-1 compared with normally menstruating women. No significant change was noted in the mean values of sVCAM-1 throughout the menstrual cycle, despite the significant change in 17beta-estradiol levels. Throughout the menstrual cycle, a significant correlation was noted between the serum levels of TNF-alpha and sVCAM-1. The serum levels of IL-6 correlated with those of sVCAM-1 in the late follicular and midluteal phase of the cycle. Similar correlations were observed in OC users.

CONCLUSION(S)

Long-term exposure to exogenous estrogens suppresses serum levels of sVCAM-1. Short-term changes in endogenous estrogens, as observed during the menstrual cycle, may not alter VCAM-1 expression; TNF-alpha and IL-6 may play a role in the regulation of VCAM-1 expression in vivo.

The phytoestrogen biochaninA weakens acute cardiac allograft rejection without affecting the reproductive system

BACKGROUND

Since the two estrogen receptor isoforms ERalpha and ERbeta have been discovered it is unclear by which receptor immunomodulating or feminizing effects are mediated. In this study, the effects of the two selective ERalpha- and ERbeta-agonists ethinylestradiol and biochaninA, respectively, on acute cardiac allograft rejection, uterus growth, vascular adhesion molecule and MHC-II expression were investigated and verified using in vitro cell culture.

METHODS

Heterotopic Lewis to ovarectomized F344 cardiac transplantations were performed. The study groups received supplemental biochaninA or ethinylestradiol, the control group received no treatment. Grafts and uteri were harvested on the fifth postoperative day and blood was taken for hormone plasma level quantifications. Purified Lewis aortic endothelial cell cultures were pre-treated with biochaninA or ethinylestradiol and stimulated with TNF-alpha or IFN-gamma for quantification of ICAM-1/VCAM-1 and MHC-II expression. Endothelium-lymphocyte adhesion assays were performed using purified F344 lymphocytes.

RESULTS

Both biochaninA and ethinylestradiol treatment significantly reduced graft mononuclear infiltration of CD8(+) and ED1(+) cells and markedly reduced ISHLT grading compared to untreated controls. Either agent significantly inhibited lymphocyte adhesion, endothelial VCAM-1 upregulation during graft rejection and during TNF-alpha-stimulation in vitro, whereas no effect was observed for ICAM-1 upregulation. BiochaninA but not ethinylestradiol significantly reduced endothelial MHC-II upregulation in vivo and in vitro. Only ethinylestradiol treatment strongly affected uterus growth in ovarectomized recipients.

CONCLUSIONS

Only the treatment with the phytoestrogen biochaninA reduced endothelial MHC-II expression in vivo and in vitro and weakened allograft rejection without affecting the reproductive system. Supplemental phytoestrogens may therefore provide further benefits in the clinical setting.

Soy-isoflavone-enriched foods and inflammatory biomarkers of cardiovascular disease risk in postmenopausal women: interactions with genotype and equol production

BACKGROUND

Dietary isoflavones are thought to be cardioprotective because of their structural similarity to estrogen. The reduction of concentrations of circulating inflammatory markers by estrogen may be one of the mechanisms by which premenopausal women are protected against cardiovascular disease.

OBJECTIVE

Our aim was to investigate the effects of isolated soy isoflavones on inflammatory biomarkers [von Willebrand factor, intracellular adhesion molecule 1, vascular cell adhesion molecule 1 (VCAM-1), E-selectin, monocyte chemoattractant protein 1, C-reactive protein (CRP), and endothelin 1 concentrations]. Differences with respect to single-nucleotide polymorphisms in selected genes [estrogen receptor alpha (XbaI and PvuII), estrogen receptor beta [ERbeta (AluI) and ERbeta[cx] (Tsp509I), endothelial nitric oxide synthase (Glu298Asp), apolipoprotein E (Apo E2, E3, and E4), and cholesteryl ester transfer protein (TaqIB)] and equol production were investigated.

DESIGN

One hundred seventeen healthy European postmenopausal women participated in this randomized, double-blind, placebo-controlled, crossover dietary intervention trial. Isoflavone-enriched (genistein-to-daidzein ratio of 2:1; 50 mg/d) or placebo cereal bars were consumed for 8 wk, with a washout period of 8 wk between the crossover. Plasma inflammatory factors were measured at 0 and 8 wk of each study arm.

RESULTS

Isoflavones improved CRP concentrations [odds ratio (95% CI) for CRP values >1 mg/L for isoflavone compared with placebo: 0.43 (0.27, 0.69)]; no significant effects of isoflavone treatment on other plasma inflammatory markers were observed. No significant differences in the response to isoflavones were observed according to subgroups of equol production. Differences in the VCAM-1 response to isoflavones and to placebo were found with ERbeta AluI genotypes.

CONCLUSION

Isoflavones have beneficial effects on CRP concentrations, but not on other inflammatory biomarkers of cardiovascular disease risk in postmenopausal women, and may improve VCAM-1 in an ERbeta gene polymorphic subgroup.

Common carotid artery stiffness, cardiovascular function and lipid metabolism after menopause

While cardiovascular disease is a major cause of death in elderly women, relatively little is known regarding the influence of menopause on atherogenesis. We tried to characterize postmenopausal changes in the arterial properties. A group of 72 postmenopausal women were classified into subgroups based on duration of the postmenopausal period (PMP): Group PM1 (1-2 years; n = 16), PM4 (2-6 years; n = 16), PM8 (6-10 years; n = 25), and PM12 (10-15 years; n = 15). The control group consisted of 24 volunteers with regular menstruation (PM0). The diameter pulse waveform and intima-media thickness (IMT) of the common carotid artery (CCA) was measured using a phase-locked echo tracking system coupled with B-mode ultrasonography. The stiffness index was calculated from the waveform and the systemic blood pressure. The cardiac contractile force and the cerebral perfusion were also estimated using the maximum incremental velocity (MIV) and the calculated blood flow, as well as the fasting lipid profile. When compared to control, significant and progressive increases were noted in total cholesterol and low density lipoprotein (PM1, PM4, PM8, PM12), IMT (PM8, PM12), and SI (PM1, PM4, PM8, PM12). Further significant and progressive reductions were noted in pulse amplitude of CCA diameter (PM1, PM4, PM8, PM12) and MIV and cerebral perfusion (PM8, PM12). The postmenopausal increase in CCA stiffness as well as lipid profile occurs earlier than the increase in IMT and may be a more sensitive predictor of disorder on arterial property.

Bridging advanced glycation end product, receptor for advanced glycation end product and nitric oxide with hormonal replacement/estrogen therapy in healthy versus diabetic postmenopausal women: A perspective

Cardiovascular diseases (CVD) are the most significant cause of death in postmenopausal women. The loss of estrogen biosynthesis with advanced age is suggested as one of the major causes of higher CVD in postmenopausal women. While some studies show beneficial effects of estrogen therapy (ET)/hormonal replacement therapy (HRT) in the cardiovascular system of healthy postmenopausal women, similar studies in diabetic counterparts contradict these findings. In particular, ET/HRT in diabetic postmenopausal women results in a seemingly detrimental effect on the cardiovascular system. In this review, the comparative role of estrogens is discussed in the context of CVD in both healthy and diabetic postmenopausal women in regard to the synthesis or expression of proinflammatory molecules like advanced glycation end products (AGEs), receptor for advanced glycation end products (RAGEs), inducible nitric oxide synthases (iNOS) and the anti-inflammatory endothelial nitric oxide synthases (eNOS). The interaction of AGE-RAGE signaling with molecular nitric oxide (NO) may determine the level of reactive oxygen species (ROS) and influence the overall redox status of the vascular microenvironment that may further determine the ultimate outcome of the effects of estrogens on the CVD in healthy versus diabetic women.