Hormone Replacement Therapy and Atherosclerosis in Postmenopausal Women

The role of sex hormones in aldosterone biosynthesis and their potential impact on its mineralocorticoid receptor

Blood pressure (BP) regulation is a complex process involving various hormones, including aldosterone and its mineralocorticoid receptor. Mineralocorticoid receptor is expressed in several tissues, including the kidney, and plays a crucial role in regulating BP by controlling the sodium and water balance. During different stages of life, hormonal changes can affect mineralocorticoid receptor activity and aldosterone levels, leading to changes in BP. Increasing evidence suggests that sex steroids modulate aldosterone levels. Estrogens, particularly estradiol, mediate aldosterone biosynthesis by activating classical estrogen receptors and the G protein-coupled receptor. Progesterone acts as an anti-mineralocorticoid by inhibiting the binding of aldosterone to the mineralocorticoid receptor. Moreover, progesterone inhibits aldosterone synthase enzymes. The effect of testosterone on aldosterone synthesis is still a subject of debate. However, certain studies show that testosterone downregulates the mRNA levels of aldosterone synthase, leading to decreased plasma aldosterone levels.

Sex and sex steroids as determinants of cardiovascular risk

There are considerable sex differences regarding the risk of cardiovascular disease (CVD), including arterial hypertension, coronary artery disease (CAD) and stroke, as well as chronic renal disease. Women are largely protected from these conditions prior to menopause, and the risk increases following cessation of endogenous estrogen production or after surgical menopause. Cardiovascular diseases in women generally begin to occur at a later age than in men (on average with a delay of 10 years). Cessation of estrogen production also impacts metabolism, increasing the risk of developing obesity and diabetes. In middle-aged individuals, hypertension develops earlier and faster in women than in men, and smoking increases cardiovascular risk to a greater degree in women than it does in men. It is not only estrogen that affects female cardiovascular health and plays a protective role until menopause: other sex hormones such as progesterone and androgen hormones generate a complex balance that differentiates heart and blood vessel function in women compared to men. Estrogens improve vasodilation of epicardial coronary arteries and the coronary microvasculature by augmenting the release of vasodilating factors such as nitric oxide and prostacyclin, which are mechanisms of coronary vasodilatation that are more pronounced in women compared to men. Estrogens are also powerful inhibitors of inflammation, which in part explains their protective effects on CVD and chronic renal disease. Emerging evidence suggests that sex chromosomes also play a significant role in shaping cardiovascular risk. The cardiovascular protection conferred by endogenous estrogens may be extended by hormone therapy, especially using bioidentical hormones and starting treatment early after menopause.

Post-Transcriptional and Epigenetic Regulation of Estrogen Signaling

Post-translational and epigenetic regulation are important mechanisms controlling functions of genes and proteins. Although the "classic" estrogen receptors (ERs) have been acknowledged to function in mediating estrogen effects via transcriptional mechanisms, estrogenic agents modulate the turnover of several proteins via post-transcriptional and post-translational pathways including epigenetics. For instance, the metabolic and angiogenic action of G-protein coupled estrogen receptor (GPER) in vascular endothelial cells has been recently elucidated. By interacting with GPER, 17β-estradiol and the GPER agonist G1 enhance endothelial stability of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and capillary tube formation by increasing ubiquitin-specific peptidase 19 levels, thereby reducing PFKFB3 ubiquitination and proteasomal degradation. In addition to ligands, the functional expression and trafficking of ERs can be modulated by post-translational modification, including palmitoylation. MicroRNAs (miRNAs), the most abundant form of endogenous small RNAs in humans, regulate multiple target genes and are at the center of the multi-target regulatory network. This review also discusses the emerging evidence of how miRNAs affect glycolytic metabolism in cancer, as well as their regulation by estrogens. Restoring dysregulated miRNA expression represents a promising strategy to counteract the progression of cancer and other disease conditions. Accordingly, estrogen post-transcriptional regulatory and epigenetic mechanisms represent novel targets for pharmacological and nonpharmacological intervention for the treatment and prevention of hormone-sensitive noncommunicable diseases, including estrogen-sensitive cancers of the reproductive system in women. SIGNIFICANCE STATEMENT: The effects of estrogen are mediated by several mechanisms that are not limited to the transcriptional regulation of target genes. Slowing down the turnover of master regulators of metabolism by estrogens allows cells to rapidly adapt to environmental cues. Identification of estrogen-targeted microRNAs may lead to the development of novel RNA therapeutics that disrupt pathological angiogenesis in estrogen-dependent cancers.

The gut microbiota during the progression of atherosclerosis in the perimenopausal period shows specific compositional changes and significant correlations with circulating lipid metabolites

Atherosclerosis (AS) is exacerbated in the perimenopausal period, which significantly increases the incidence rate of cardiovascular disease. The disruption of the gut microbiota has been associated with AS or menopause, but the specific changes of AS-associated gut microbiota in the perimenopausal period remain largely unknown. As lipid abnormalities are mainly responsible for AS, the relationship between lipid metabolism abnormalities and gut microbiota disruptions during menopause is rarely reported hitherto. In the present study, ApoE^-/- mice fed with a high-fat diet (HFD) were subjected to ovariectomy and supplemented with estrogen. The ovariectomized HFD-fed ApoE^-/- mice underwent significant AS damage, hepatic lipid damage, hyperlipidemia, and changes of lipid metabolism- and transport-related enzymes. There was significantly higher abundance of some lipid metabolites in the plasma of ovariectomized HFD-fed ApoE^-/- mice than in non-ovariectomized ones, including cholesterol esters, triglycerides, phospholipids, and other types of lipids (free fatty acids, acylcarnitine, sphingomyelins, and ceramides). The administration of estrogen significantly reduced the contents of most lipid metabolites. The diversity and composition of gut microbiota evidently changed in ovariectomized HFD-fed ApoE^-/- mice, compared to HFD-fed ApoE^-/- mice without ovariectomy. In contrast, with estrogen supplementation, the diversity and composition of gut microbiota were restored to approach that of non-ovariectomized HFD-fed ApoE^-/- mice, and the relative abundances of some bacteria were even like those of C57BL/6 mice fed with a normal diet. On the other hand, the transplantation of feces from C57BL/6 mice fed with normal diet to ovariectomized HFD-fed ApoE^-/- mice was sufficient to correct the hyperlipidemia and AS damage, and to reverse the characteristics changing of lipid metabolomics in ovariectomized HFD-fed ApoE^-/- mice. These phenomena were also been observed after transplantation of feces from estrogen-treated ovariectomized HFD-fed ApoE^-/- mice to ovariectomized HFD-fed ApoE^-/- mice. Moreover, the gut microbiota and lipid metabolites were significantly correlated, demonstrating that the changes of serum lipids may be associated with the gut microbiota disruptions in the perimenopausal period. In conclusion, the gut microbiota during the progression of AS in the perimenopausal period showed specific compositional changes and significant correlations with circulating lipid metabolites. Estrogen supplementation may exert beneficial effects on gut bacteria and lipid metabolism.

Effects of Estrogen on Cardiac mRNA and LncRNA Expression Profiles in Hypertensive Mice

Estrogen is a vascular protection factor and plays a protective role in the pathogenesis of gender differences in cardiovascular diseases. This study was to address the possible mechanisms that may explain the relationship between estradiol configuration-17β-estradiol (E2) and ventricular remodeling. Here, we show that a total of 1499 LncRNAs and 680 mRNAs significantly differently expressed were identified. This result indicates that estradiol has a global role in regulating heart gene expression profiles in female mice. Go and Pathway functional cluster analysis showed that the antagonism of E2 on cardiac remodeling and AngII-induced pathological changes in female mice may be related to physiological processes such as circadian rhythm disorder and ion channel dysfunction. Graphical Abstract.

Estrogen Plays a Crucial Role in Rab9-Dependent Mitochondrial Autophagy, Delaying Arterial Senescence

Background

The risk of cardiovascular disease is known to increase after menopause. Mitochondria, which undergo quality control via mitochondrial autophagy, play a crucial role in the regulation of cellular senescence. The aim of this study was to investigate whether the effect of estrogen‐mediated protection from senescence on arteries is attributed to the induction of mitochondrial autophagy.

Methods and Results

We used human umbilical vein cells, vascular smooth muscle cells, and 12‐week‐old female C57BL/6 mice. The administration of 17β‐estradiol (E2) to cells inhibited cellular senescence and mitochondrial dysfunction. Furthermore, E2 increased mitochondrial autophagy, maintaining mitochondrial function, and retarding cellular senescence. Of note, E2 did not modulate LC3 (light chain 3), and ATG7 (autophagy related 7) deficiency did not suppress mitochondrial autophagy in E2‐treated cells. Conversely, E2 increased the colocalization of Rab9 with LAMP2 (lysosomal‐associated membrane protein 2) signals. The E2‐mediated effects on mitochondrial autophagy were abolished by the knockdown of either Ulk1 or Rab9. These results suggest that E2‐mediated mitochondrial autophagy is associated with Rab9‐dependent alternative autophagy. E2 upregulated SIRT1 (sirtuin 1) and activated LKB1 (liver kinase B1), AMPK (adenosine monophosphate‐activated protein kinase), and Ulk1, indicating that the effect of E2 on the induction of Rab9‐dependent alternative autophagy is mediated by the SIRT1/LKB1/AMPK/Ulk1 pathway. Compared with the sham‐operated mice, ovariectomized mice showed reduced mitochondrial autophagy and accelerated mitochondrial dysfunction and arterial senescence; these detrimental alterations were successfully rescued by the administration of E2.

Conclusions

We showed that E2‐induced mitochondrial autophagy plays a crucial role in the delay of vascular senescence. The Rab9‐dependent alternative autophagy is behind E2‐induced mitochondrial autophagy.

Postmenopausal hormone therapy for cardiovascular health: the evolving data

Postmenopausal (PM) hormone therapy (HT) was extremely popular for years as a treatment for many conditions, including cardiovascular (CV) disease (CVD) prevention. The adverse results from the Women's Health Initiative (WHI) ended the widespread prescriptive use of HT for nearly 20 years. The WHI findings have been broadly and unfairly applied to all hormone formulations, including modern treatments using human-identical hormones. Although CV health is indisputably linked to oestrogen status, HT involving any combination of hormones currently is not recommended for primary or secondary prevention of CVD. In the wake of more positive results from recent studies and re-evaluation of the WHI, HT has re-emerged as an issue for specialists in CVD to discuss with their patients. Rigorous scientific analysis is needed to explain the paradox of cardioprotection conferred by endogenous ovarian hormones with apparent cardiotoxicity inflicted by HT. This review will cover the origins of HT, hormone terminology and function, and key studies that contribute to our current understanding. Based on evolving evidence, if HT is to be used, we propose it be initiated immediately after cessation of ovarian hormone production and dosed as transdermal oestradiol combined with cyclic dosing of human-identical progesterone (P4).

Role of estrogen receptors in modulating aldosterone biosynthesis and blood pressure

Blood pressure is lower in premenopausal women than in age-matched men; after menopause blood pressure values and the prevalence of hypertension show opposite trends indicating that estrogens contribute to maintaining normal blood pressure values in women. In experimental studies menopause increases aldosterone levels, an effect alleviated by estrogen treatment. We have recently discovered a role of estrogen receptors (ER) in controlling aldosterone biosynthesis in the human adrenocortical zona glomerulosa, which expresses both the classical ERα and β receptors and G protein-coupled estrogen receptor (GPER). We have also identified that GPER mediates an aldosterone-induced aldosterone response. We found that 17 β-estradiol exerts a dual effect: it blunts aldosterone production via ERβ, but displays a potent aldosterone secretagogue effect via GPER activation after ERβ blockade. Thus, in premenopausal women high estrogen levels might tonically blunt aldosterone synthesis via ERβ, thereby maintaining normal blood pressure; after menopause loss of this estrogen-mediated inhibition can contribute to increasing blood pressure via GPER-mediated aldosterone release. The additional findings that GPER mediates an aldosterone-induced stimulation of aldosterone biosynthesis and that GPER predominates in aldosterone-producing adenomas strongly involves this receptor in the pathophysiology of primary aldosteronism. Our purpose here was to provide an update on estrogen receptor function in the normal adrenal cortex and its relevance for the sex differences in blood pressure in light of the newly discovered role of GPER in regulating aldosterone synthesis. The implications of the novel knowledge for the treatment of estrogen-dependent malignancies with ER modulators are also discussed.

The association of age at menopause and all-cause and cause-specific mortality by race, postmenopausal hormone use, and smoking status

While a mean age at menopause of 51 years has been reported in the United States (U.S.), some U.S. women experience menopause before age 45, possibly increasing risk of cardiovascular mortality; however, the role in all-cause and cerebrovascular-related mortality is unclear. The purpose of this study was to investigate the association between age at menopause and all-cause and cause-specific mortality by race, hormone replacement therapy (HRT) use, and smoking status. REasons for Geographic and Racial Differences in Stroke (REGARDS) is a population-based study of 30,239 participants aged ≥45 years enrolled between 2003 and 2007 of whom 14,361 were postmenopausal women. Age at menopause was defined as <45 (early) or ≥45. All-cause and cause-specific mortality were ascertained through 2013. Cox proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for the association between age at menopause and mortality, adjusting for baseline measures. Of 11,287 eligible women (6403 white; 4884 black), mean menopause age was 45.2 (SD 7.9) with 1524 deaths over 7.1 years. Significant interactions were detected between early age at menopause (39%) and HRT use in association with all-cause mortality (p < 0.01), mortality from coronary heart disease (p = 0.06), and mortality from all other causes (p = 0.04). An association between early age at menopause and all-cause mortality was observed among ever-HRT users (HR = 1.31, 95% CI: 1.10–1.56), but not never-HRT users (HR = 1.01, 95% CI: 0.85–1.20). There were no differences in associations examined by race or smoking status. Increased all-cause mortality risk was observed for ever-HRT users with menopause before age 45.

•

Increased all-cause mortality risk in ever-HRT users with menopause before age 45

•

HRT use modified the association of menopause before age 45 and CHD mortality.

•

There were no differences in associations examined by race or smoking status.

Aging women and their endothelium: probing the relative role of estrogen on vasodilator function

Despite significant decreases in cardiovascular disease (CVD) mortality in the past three decades, it still remains the leading cause of death in women. Following menopause and the accompanying loss of estrogen, women experience a unique, accelerated rise in CVD risk factors. Dysfunction of the endothelium represents an important antecedent to CVD development, with rapid declines in endothelial vasodilator function reportedly taking place across the menopause transition. Importantly, the decline in endothelial function is independent of chronological age and is associated with estrogen deficiency. Estrogen-mediated effects, including increasing nitric oxide bioavailability and attenuating oxidative stress and inflammation, contribute to preserving endothelial health. This review will discuss studies that have probed the role of estrogen on endothelial vasodilator function in women at discrete stages of the menopause transition and the effects of estradiol supplementation in postmenopausal women. Estrogen receptor signaling is also an important aspect of endothelial function in women, and studies suggest that expression is reduced with both acute and prolonged estrogen deficiency. Changes in regulatory mechanisms of estrogen receptor-α expression as well as sensitivity to estrogen may underlie the differential effects of estrogen therapy in early (≤5 yr past final menstrual period) and late postmenopausal women (>5 yr past final menstrual period). Lastly, this review presents potential therapeutic targets that include increasing l-arginine bioavailability and estrogen receptor activation to prevent endothelial dysfunction in postmenopausal women as a strategy for decreasing CVD mortality in this high-risk population.

Estrogen-SIRT1 Axis Plays a Pivotal Role in Protecting Arteries Against Menopause-Induced Senescence and Atherosclerosis

Aim: Menopause causes arterial senescence and atherosclerotic development through decrease of estrogen. Recently, histone deacetylase SIRT1 has been reported to have protective effects against arterial senescence and atherosclerosis. However, the relationship between estrogen and SIRT1 in the context of menopause-induced arterial senescence is not well understood. The present study aims to investigate whether SIRT1 is involved in the etiology of menopause-induced arterial senescence and atherosclerotic development.

Methods: Twelve-week old female apolipoprotein E-knockout (ApoE-KO) mice underwent ovariectomy (OVX) or sham surgery.

Results: SIRT1 expression and endothelial nitric oxide synthase (eNOS) activation in the aorta were significantly lower in OVX mice than they were in sham mice (OVX vs. sham, n = 5 per group). Senescence-associated β-galactosidase activity, protein expression of Ac-p53 and PAI-1, and aortic atherosclerosis lesions were significantly greater in OVX mice than they were in sham mice. Administration of 17β-estradiol (E2) for eight weeks to OVX mice restored aortic SIRT1 expression, activated eNOS, and retarded OVX-induced arterial senescence and atherosclerotic development (E2 vs. control, n = 5 per group). The effects of E2 on SIRT1 upregulation, anti-senescence and anti-atherosclerosis were attenuated by administration of a SIRT1 inhibitor, sirtinol. In vitro experiment using human endothelial cells demonstrated that E2 also increased SIRT1 expression and retarded oxidized low density lipoprotein-induced premature senescence, which were also abolished by sirtinol. These results suggested that estrogen modulated arterial senescence and atherosclerosis through SIRT1. Additionally a selective estrogen receptor modulator (SERM), bazedoxifene, also augmented SIRT1 and inhibited arterial senescence and atherosclerotic development (SERM vs. control, n = 3 per group).

Conclusions: Downregulation of SIRT1 causes OVX-induced arterial senescence and atherosclerosis in ApoE-KO mice. Administration of estrogen or SERM enables OVX mice to restore these alterations by SIRT1 induction.

Hormone replacement therapy and prevention of chronic conditions

Nowadays, postmenopausal women are largely undertreated. Analysis of conflicting results among different studies suggests that hormone replacement therapy (HRT) can prevent osteoporosis and cardiovascular disease in symptomatic, early postmenopausal women. In fact, climacteric symptoms are related to an increased risk of chronic conditions, including hypertension and cardiovascular disease. Different scientific societies have pointed out that patient selection, timing of initiation, and the choice of the type and dose of HRT used are the major determinants of the ultimate effect of HRT on women's health and quality of life in selected women. HRT may prevent chronic conditions when started in symptomatic women before the age of 60 years or within 10 years of the onset of the menopause, taking into consideration the characteristics and risk profiles of each given woman. The bulk of scientific evidence from preclinical, clinical, epidemiological, and also randomized studies indicates that wisely selected HRT is generally useful and rarely dangerous. Following simple and well-established rules, HRT benefits outweigh all of the possible risks. Progestogen choice can make the difference in terms of cardiovascular disease benefits.

Equilin displays similar endothelium-independent vasodilator potential to 17β-estradiol regardless of lower potential to inhibit calcium entry

Conjugated equine estrogens (CEE) have been widely used by women who seek to relieve symptoms of menopause. Despite evidence describing protective effects against risk factors for cardiovascular diseases by naturally occurring estrogens, little is known about the vascular effects of equilin, one of the main components of CEE and not physiologically present in women. In this regard, the present study aims to compare the vascular effects of equilin in an experimental model of hypertension with those induced by 17β-estradiol. Resistance mesenteric arteries from female spontaneously hypertensive rats (SHR) were used for recording isometric tension in a small vessel myograph. As effectively as 17β-estradiol, equilin evoked a concentration-dependent relaxation in mesenteric arteries from female SHRs contracted with KCl, U46619, PDBu or ET-1. Equilin-induced vasodilation does not involve classical estrogen receptor activation, since the estrogen receptor antagonist (ICI 182,780) failed to inhibit relaxation in U46619-precontracted mesenteric arteries. Vasorelaxation was not affected by either endothelium removal or by inhibiting the release or action of endothelium-derived factors. Incubation with L-NAME (NOS inhibitor), ODQ (guanylyl cyclase inhibitor) or KT5823 (inhibitor of protein kinase G) did not affect equilin-induced relaxation. Similarly, indomethacin (COX inhibitor) or blockage of potassium channels with tetraethylammonium, glibenclamide, 4-aminopyridine, or ouabain did not affect equilin-induced relaxation. Inhibitors of adenylyl cyclase SQ22536 or protein kinase A (KT5720) also had no effects on equilin-induced relaxation. While 17β-estradiol inhibited calcium (Ca²⁺) -induced contractions in high-K⁺ depolarization medium in a concentration-dependent manner, equilin induced a slight rightward-shift in the contractile responses to Ca²⁺. Comparable pattern of responses were observed in the concentration-response curves to (S)-(-)-Bay K 8644, a L-type Ca²⁺ channel activator. Equilin was unable to block the transitory contraction produced by caffeine-induced Ca²⁺ release from intracellular stores. In conclusion, equilin blocks L-type Ca²⁺ channels less effectively than 17β-estradiol. Despite its lower effectiveness, equilin equally relaxes resistance mesenteric arteries by blocking Ca²⁺ entry on smooth muscle.

Association of Severity of Coronary Lesions with Bone Mineral Density in Postmenopausal Women

Background

Coronary artery disease (CAD) and osteoporosis (OP) are common diseases in postmenopausal women. In both cross-sectional and longitudinal epidemiologic studies, low bone mass has been related to increased frequency of CAD. However, available data on the relationship between bone mineral density (BMD) and severity of coronary lesions is limited.

Objective

To investigate association between the BMD and severity of coronary lesions assessed by Gensini score in postmenopausal women.

Methods

This study included 122 postmenopausal women who were diagnosed with CAD. These patients were divided into two groups according to the severity of coronary lesions assessed by the Gensini score - patients with mild coronary lesions (Gensini score < 25) and patients with severe coronary lesions (Gensini score ≥ 25). Femoral neck mineral density was measured with dual energy X-ray absorptiometry (DXA).

Results

The study included postmenopausal women aged 64.31 ± 4.71 years, 85 of whom (69.7%) exhibited severe coronary lesions. Participants with severe coronary lesions had a significantly higher T score than did those with mild coronary lesions at the femoral neck (p < 0.05). The mean T-score was −0.84 ± 1.01 in mild coronary lesions group, −1.42 ± 1.39 in severe coronary lesions group (p < 0.05). Multivariable logistic regression analysis showed that osteopenia-osteoporosis at the Femoral neck (odds ratio 2.73; 95% confidence interval 1.06 to 6.13) was associated with an increased risk of developing severe coronary lesions. The multiple regression model showed that T-scores (b = −0.407, SE = 0.151, p=0.007) were the independent predictors of Gensini score.

Conclusion

The relationship between severity of coronary lesions and BMD was significant in postmenopausal women. BMD, a low-cost technique involving minimal radiation exposure, widely used for osteoporosis screening, is a promising marker of severity of coronary lesions.

Hypertension Across a Woman's Life Cycle

Hypertension accounts for 1 in 5 deaths among American women, posing a greater burden for women than men, and is among their most important risk factors for death and development of cardiovascular and other diseases. Hypertension affects women in all phases of life, with specific characteristics relating to risk factors and management for primary prevention of hypertension in teenage and young adult women; hypertension in pregnancy; hypertension during use of oral contraceptives and assisted reproductive technologies, lactation, menopause, or hormone replacement; hypertension in elderly women; and issues of race and ethnicity. All are detailed in this review, as is information relative to women in clinical trials of hypertension and medication issues. The overarching message is that effective treatment and control of hypertension improves cardiovascular outcomes. But many knowledge gaps persist, including the contribution of hypertensive disorders of pregnancy to cardiovascular disease risk, the role of hormone replacement, blood pressure targets for elderly women, and so on.

Non-HDL cholesterol is a good predictor of the risk of increased arterial stiffness in postmenopausal women in an urban Brazilian population

OBJECTIVES:

Increased arterial stiffness is an important determinant of the risk of cardiovascular disease. Lipid profile impairment, especially hypercholesterolemia, is associated with stiffer blood vessels. Thus, the aim of this study was to determine which of the five circulating lipid components (high-density lipoprotein cholesterol (HDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL), total cholesterol (TC) and triglycerides) is the best predictor of increased arterial stiffness in an urban Brazilian population.

METHODS:

A random sample of 1,662 individuals from the general population of Vitoria, Brazil (25-64 years), was selected, and lipid components were measured using standard methods. Pulse wave velocity was measured using a non-invasive automatic device, and increased arterial stiffness was defined as a pulse wave velocity ≥10 m/s.

RESULTS:

In men, only total cholesterol (OR=1.59; CI=1.02 to 2.48, p=0.04) was associated with the risk of increased arterial stiffness. In women, HDL-C (OR=1.99; CI=1.18 to 3.35, p=0.01) and non-HDL-C (OR=1.61; CI=1.01 to 2.56, p=0.04) were good predictors of the risk of increased arterial stiffness. However, these associations were only found in postmenopausal women (OR=2.06; CI=1.00 to 4.26, p=0.05 for HDL-C and OR=1.83; CI=1.01 to 3.33, p=0.04 for non-HDL-C).

CONCLUSION:

Our findings indicate that both HDL-C and non-HDL-C are good predictors of the risk of increased arterial stiffness in postmenopausal women in an urban Brazilian population and may be useful tools for assessing the risk of arterial stiffness.

Serum Thyroid Stimulating Hormone Levels Are Associated with the Presence of Coronary Atherosclerosis in Healthy Postmenopausal Women

Objectives

Menopause is a natural aging process causing estrogen deficiency, accelerating atherogenic processes including dyslipidemia. Prevalence of thyroid dysfunction is also high in postmenopausal women, and it is known to elevate the risk of cardiovascular disease (CVD). Therefore, we are to study on the associations in between serum thyroid stimulating hormone (TSH) and prevalence of CVD in postmenopausal women who have normal thyroid function.

Methods

We performed a retrospective review of 247 Korean postmenopausal women who visited the health promotion center from January, 2007 to December, 2009. Postmenopausal women with normal serum TSH were included in the study. Coronary atherosclerosis was assessed by 64-row multidetector computed tomography.

Results

In multiple linear regression analysis, serum TSH was associated with serum triglyceride (TG) (β = 0.146, P = 0.023). In multiple logistic regression analysis, increasing age and serum TSH were associated with an increased risk of coronary atherosclerosis in euthyroid postmenopausal women (odds ratio [OR] = 1.107 [1.024-1.197], P = 0.011 and OR = 1.303 [1.024-1.658], P = 0.031, respectively).

Conclusions

It revealed that significant predictor of serum TSH was serum TG, and increasing age and TSH were found to have associations with an increased risk of coronary atherosclerosis in euthyroid postmenopausal women. Screening and assessing risks for CVD in healthy postmenopausal women would be helpful before atherosclerosis develops.

Estrogens and Coronary Artery Disease: New Clinical Perspectives

In premenopausal women, endogenous estrogens are associated with reduced prevalence of arterial hypertension, coronary artery disease, myocardial infarction, and stroke. Clinical trials conducted in the 1990s such as HERS, WHI, and WISDOM have shown that postmenopausal treatment with horse hormone mixtures (so-called conjugated equine estrogens) and synthetic progestins adversely affects female cardiovascular health. Our understanding of rapid (nongenomic) and chronic (genomic) estrogen signaling has since advanced considerably, including identification of a new G protein-coupled estrogen receptor (GPER), which like the "classical" receptors ERα and ERβ is highly abundant in the cardiovascular system. Here, we discuss the role of estrogen receptors in the pathogenesis of coronary artery disease and review natural and synthetic ligands of estrogen receptors as well as their effects in physiology, on cardiovascular risk factors, and atherosclerotic vascular disease. Data from preclinical and clinical studies using nonselective compounds activating GPER, which include selective estrogen receptor modulators such as tamoxifen or raloxifene, selective estrogen receptor downregulators such as Faslodex™ (fulvestrant/ICI 182,780), vitamin B3 (niacin), green tea catechins, and soy flavonoids such as genistein or resveratrol, strongly suggest that activation of GPER may afford therapeutic benefit for primary and secondary prevention in patients with or at risk for coronary artery disease. Evidence from preclinical studies suggest similar efficacy profiles for selective small molecule GPER agonists such as G-1 which are devoid of uterotrophic activity. Further clinical research in this area is warranted to provide opportunities for future cardiovascular drug development.

Accelerated Vascular Aging as a Paradigm for Hypertensive Vascular Disease: Prevention and Therapy

Aging is considered the most important nonmodifiable risk factor for cardiovascular disease and death after age 28 years. Because of demographic changes the world population is expected to increase to 9 billion by the year 2050 and up to 12 billion by 2100, with several-fold increases among those 65 years of age and older. Healthy aging and prevention of aging-related diseases and associated health costs have become part of political agendas of governments around the world. Atherosclerotic vascular burden increases with age; accordingly, patients with progeria (premature aging) syndromes die from myocardial infarctions or stroke as teenagers or young adults. The incidence and prevalence of arterial hypertension also increases with age. Arterial hypertension-like diabetes and chronic renal failure-shares numerous pathologies and underlying mechanisms with the vascular aging process. In this article, we review how arterial hypertension resembles premature vascular aging, including the mechanisms by which arterial hypertension (as well as other risk factors such as diabetes mellitus, dyslipidemia, or chronic renal failure) accelerates the vascular aging process. We will also address the importance of cardiovascular risk factor control-including antihypertensive therapy-as a powerful intervention to interfere with premature vascular aging to reduce the age-associated prevalence of diseases such as myocardial infarction, heart failure, hypertensive nephropathy, and vascular dementia due to cerebrovascular disease. Finally, we will discuss the implementation of endothelial therapy, which aims at active patient participation to improve primary and secondary prevention of cardiovascular disease.

Estrogen receptor β actions in the female cardiovascular system: A systematic review of animal and human studies

Five medical databases were searched for studies that assessed the role of ERβ in the female cardiovascular system and the influence of age and menopause on ERβ functioning. Of 9472 references, 88 studies met our inclusion criteria (71 animal model experimental studies, 15 human model experimental studies and 2 population based studies). ERβ signaling was shown to possess vasodilator and antiangiogenic properties by regulating the activity of nitric oxide, altering membrane ionic permeability in vascular smooth muscle cells, inhibiting vascular smooth muscle cell migration and proliferation and by regulating adrenergic control of the arteries. Also, a possible protective effect of ERβ signaling against left ventricular hypertrophy and ischemia/reperfusion injury via genomic and non-genomic pathways was suggested in 27 studies. Moreover, 5 studies reported that the vascular effects of ERβ may be vessel specific and may differ by age and menopause status. ERβ seems to possess multiple functions in the female cardiovascular system. Further studies are needed to evaluate whether isoform-selective ERβ-ligands might contribute to cardiovascular disease prevention.

Estrogen effects on vascular inflammation are age dependent: role of estrogen receptors

OBJECTIVE

17β-Estradiol (E2) offers cardiovascular protection in young female animals and postmenopausal women. In contrast, randomized trials of menopausal hormones performed in older women have shown harm or no cardiovascular benefit. We hypothesize that E2 effects on vascular inflammation are age dependent.

APPROACH AND RESULTS

Young (10 weeks) and aged (52 weeks) female C57BL/6 mice were used as source for primary cultures of bone marrow-derived macrophages (BMMs) and vascular smooth muscle cells (VSMCs). E2 pretreatment of cells derived from young mice attenuated C-reactive protein (CRP)-induced expression of inflammatory mediators. In contrast, E2 pretreatment of cells from aged mice did not alter (BMMs) or paradoxically exaggerated (VSMCs) inflammatory mediator response to CRP. Using E2 receptor (ER) knockout mice, we demonstrated that E2 regulates inflammatory response to CRP in BMMs via ERα and in VSMCs via ERβ. BMMs derived from aged (versus young) mice expressed significantly less ERα mRNA and protein. A selective ligand of the novel ER GPR30 reproduced the E2 effects in BMMs and VSMCs. Unlike in young mice, E2 did not reduce neointima formation in ligated carotid arteries of aged CRP transgenic mice.

CONCLUSIONS

E2 attenuates inflammatory response to CRP in BMMs and VSMCs derived from young but not aged mice and reduces neointima formation in injured carotid arteries of young but not aged CRP transgenic mice. ERα expression in BMMs is greatly diminished with aging. These data suggest that vasoprotective effects of E2 are age dependent and may explain the vasotoxic effects of E2 seen in clinical trials of postmenopausal women.

Non-modifiable Factors of Coronary Artery Stenosis in Late Onset Patients with Coronary Artery Disease in Southern Iranian Population

Introduction: Coronary Artery disease (CAD) is influenced by genetic factors, environment and culture behavior. The aim of the present study was to evaluate some non-modifiable risk factors of coronary heart disease such as sex, age, family history and consanguineous marriage.

Methods: This is a case-control study. The study population consisted of 200 fifteen or more years old. Data were collected on 200 patients with positive angiography and 200 control subjects with negative angiography. Positive angiography was defined as coronary diameter cut greater than 50%. Statistical analysis was conducted using SPSS 11.5. In this study, data were collected through a checklist. Logistic regression and stratification were used to determine the impact of age, gender, family history, and consanguinity on the risk of stenosis.

Results: The percentage of men in patients and controls were 89% and 29%, respectively. As to gender, a significant association was found between patients and controls of CAD (CI 95%, 4.014-10.052, OR 6.352). Gender was determined as a risk factor for CAD. Family history of myocardial infarction did not show a significant effect on the artery stenosis. As to consanguinity of the parents, there was no significant association between patients and controls of CAD (P> 0.05).

Conclusion: These researches show that ageing increases the risk of coronary heart stenosis; also, females are more than men protected against this disease. The impact of family history of myocardial infarction and consanguineous marriage were not associated with of CAD.

Modified relaxation technique for treating hypertension in Thai postmenopausal women

Aim

To examine the effectiveness of a modified relaxation (MR) technique in reducing blood pressure levels in Thai postmenopausal women with mild hypertension, compared with a control group who received health education.

Methods

This is a 16-week, randomized, parallel, open-label, controlled trial in a menopausal clinic in a tertiary health care center in Northeastern Thailand. The intervention group received a 60-minute session of MR training and were encouraged to practice 15–20 minutes a day, at least 5 days a week. The control group received lifestyle education, including diet and exercise. The primary and secondary outcomes were systolic and diastolic blood pressure (SBP and DBP).

Results

Of 432 participants, 215 and 217 were randomly allocated to the MR and control groups, respectively. Of those, 167 participants in the MR group and 175 participants in the control group completed the study. The SBP was significantly more reduced in the MR group, with a mean of 2.1 mmHg (P < 0.001). There was no significant difference between groups on the changed DBP.

Conclusion

The MR technique may be effective in lowering SBP in Thai postmenopausal women visiting a menopause clinic. Its efficacy may be observed as soon as 4 weeks after start of treatment. Long-term and combined relaxation therapy and antihypertensive agents are warranted in a large cohort of this population. This trial is registered in clinicaltrials.gov (number NCT01429662).

Pregnancy followed by delivery may affect circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 levels in women of reproductive age

Background/Objective. It is known that menopause or lack of endogenous estrogen is a risk factor for endothelial dysfunction and CAD. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is involved inmultiple phases of vascular dysfunction.The purpose of the current study was to determine the association between soluble LOX-1 (sLOX-1) and pregnancy followed by delivery in women of reproductive age. Materials/Methods. Sixty-eight subjects with pregnancy followed by delivery (group 1) and 57 subjects with nongravidity (group 2) were included in this study. Levels of sLOX-1 were measured in serum by EL SA. Results. Plasma levels of sLOX-1 were significantly lower in Group 1 than Group 2 in women of reproductive age (0.52 ± 0.18 ng/mL and 0.78 ± 0.13, resp., P < 0.001). There were strong correlations between sLOX-1 levels and the number of gravida (r = −0.645, P < 0.001). The levels of sLOX-1 highly correlated with the number of parous (r = −0.683, P < 0.001). Conclusion. Our study demonstrated that serum sLOX-1 levels were associated with pregnancy followed by delivery that might predict endothelial dysfunction. We conclude that pregnancy followed by delivery may delay the beginning and progress of arteriosclerosis and its clinical manifestations in women of reproductive age.

GPER/GPR30 and Regulation of Vascular Tone and Blood Pressure

Natural estrogens such as 17β-estradiol are endogenous vasodilators and have been implicated in the gender differences of hypertension. These hormones activate estrogen receptors ERα and ERβ, which mediate part of estrogen-dependent vasodilation. In addition, a novel G protein-coupled estrogen-binding receptor termed GPER/GPR30 has been identified that is expressed in the cardiovascular system. Using knock-out animals or drugs selectively targeting GPER/GPR30, a significant role for this receptor as a mediator of acute estrogen-dependent vasodilation involving nitric oxide (NO) and blood pressure-lowering activity has been demonstrated. The accumulating evidence that GPER/GPR30 is responsible for control of vascular tone indicates that this receptor may represent a novel drug target for pharmacologic treatment of hypertension in postmenopausal women and possibly also men.

AMPK Alpha 1-Induced RhoA Phosphorylation Mediates Vasoprotective Effect of Estradiol

Objective—

Estradiol (E2) mediates numerous beneficial effects assigned to estrogens, but whereas mechanisms have been described at the endothelial level, direct effects on vascular smooth muscle cells (VSMC) are poorly documented. As evidence accumulates regarding the role of RhoA in vascular pathophysiology and the benefit of RhoA-Rho associated protein kinase (Rock) pathway inhibition, we analyzed if E2 could inhibit it in VSMC.

Methods and Results—

We show that in VSMC, E2 inhibits the RhoA-Rock pathway in a time- and concentration-dependent manner. The inhibition of RhoA-Rock pathway results from E2-induced phosphorylation of the Ser188 of RhoA. Using pharmacological, transfection, and in vitro phosphorylation experiments, we demonstrate that AMP-activated protein kinase subunit alpha 1 (AMPKα1) is activated by estrogen receptor stimulation and catalyzes RhoA phosphorylation induced by E2. Ex vivo, ovariectomy leads to an increase in the amplitude of phenylephrine- or serotonine-induced contractions of aortic rings in wild-type mice but not in AMPKα1-knock-out mice or E2-supplemented animals. These functional effects were correlated with a reduced level of RhoA phosphorylation in the aorta of ovariectomized female, male, and AMPKα1 knock-out mice.

Conclusion—

Our work thus defines AMPKα1 as (1) a new kinase for RhoA and (2) a new mediator of the vasoprotective effects of estrogen.

Effects of estrogen on stress-induced premature senescence of vascular smooth muscle cells: a novel mechanism for the "time window theory" of menopausal hormone therapy

OBJECTIVES

To investigate the effects of estrogen on stress-induced premature senescence of vascular smooth muscle cells (VSMCs) and the underlying mechanisms.

METHODS

VSMCs of passage 2-3 cultured from young (2 months) and old (18 months) female SD rats were induced into premature senescence by exposure to 150 μmol/L H(2)O(2) in the presence or absence of different concentrations of 17β-estradiol (E(2)). The expression or activation of senescence-associated beta-galactosidase (SA-β-Gal), DcR2, oncogene Ras, p38, PRAK, p53, p21, p16 and Rb was detected by flow cytometry, pull-down assay or Western blot.

RESULTS

Flow cytometry analysis showed that in the VSMCs from young rats pre-administration of E(2) significantly suppressed the H(2)O(2)-induced premature senescence (reducing both percentage of SA-β-Gal positive cells and cellular expression of DcR2) in a dose-dependent manner; these senescent-inhibiting effects of E(2) could be blocked by an estrogen receptor antagonist ICI 182,780 (10(-5)mol/L). Pull-down assay or Western blot analysis revealed that pre-administration of 10(-8)mol/L E(2) significantly reduced the H(2)O(2)-induced activation of oncogene Ras, as well as activity of p16 and p38 MAPK, and expression of PRAK, p53, p21 and p-Rb. Unexpectedly, in the VSMCs from old rats the senescent-inhibiting effect of E(2) disappeared and switched to a senescent-promoting action at 10(-8)mol/L. This senescent-promoting effect could be enhanced by ICI 182,780 and eliminated by a cytochrome P450s inhibitor ABT.

CONCLUSION

Estrogen inhibits stress-induced premature senescence of VSMCs from young female through its receptor-mediated suppression of both Ras-p38-PRAK-p53-p21-Rb and Ras-p16-Rb pathways, but this effect disappeared and even more switched to a senescent-promoting action in the cells from old body probably due to a side effect of estrogen metabolites.

Sex-based differences in vascular function

Cardiovascular disease is the leading cause of morbidity and mortality for both men and women in the USA. However, there are differences between the sexes in age-dependent onset, severity, symptoms and outcomes. Basic research into the causes of sex-dependent differences in cardiovascular disease is ongoing and includes investigation into genetic variation in expression and distribution of receptors for the sex steroids; specificity of natural and synthetic ligands that activate the sex steroid receptors; and intracellular mechanisms that are activated by the receptors in all components of the vessel wall and blood elements, which integrate to regulate vascular tone, vascular repair and remodeling in health and disease. In this era of personalized medicine, basic research into mechanisms of sex differences in vascular function will result in improved prevention, detection and treatment of cardiovascular disease in both men and women.

Claudin-5 as a Novel Estrogen Target in Vascular Endothelium

Objective— Estrogens have multiple effects on vascular physiology and function. In the present study, we look for direct estrogen target genes within junctional proteins.

Methods and Results— We use murine endothelial cell lines of brain and heart origin, which express both subtypes of estrogen receptor, ERα and ERβ. Treatment of these cells with 17β-estradiol (E2) led to an increase in transendothelial electric resistance and a most prominent upregulation of the tight junction protein claudin-5 expression. A significant increase of claudin-5 promoter activity, mRNA, and protein levels was detected in cells from both vascular beds. In protein lysates and in immunoreactions on brain sections from ovariectomized E2-treated mice, we noticed an increase in claudin-5 protein and mRNA content. Treatment of cells with a specific ERβ agonist, diarylpropionitrile, revealed the same effect as E2 stimulation. Moreover, we detected significantly lower claudin-5 mRNA and protein content in ERβ knockout mice.

Conclusions— We describe claudin-5 as a novel estrogen target in vascular endothelium and show in vivo (brain endothelium) and in vitro (brain and heart endothelium) effects of estrogen on claudin-5 levels. The estrogen-induced increase in junctional protein levels may lead to an improvement in vascular structural integrity and barrier function of vascular endothelium.

Non-genomic regulation of vascular cell function and growth by estrogen

Estrogens exert rapid, non-genomic effects, which are mediated by plasma membrane-associated estrogen receptors (mER) mERalpha and mERbeta, and the intracellular transmembrane G protein-coupled estrogen receptor (GPER). Membrane-initiated responses contribute to transcriptional activation, resulting in a complex interplay of nuclear and extra-nuclear mechanisms that mediate the acute physiological responses to estrogens. Non-genomic estrogen signaling also activates a variety of intracellular estrogen signaling pathways that regulate vascular function and cell growth involving rapid but also long-term effects. This review discusses recent advances in understanding of the mechanisms of non-genomic estrogen receptor signaling in the vascular wall.

Vascular endothelial estrogen receptor alpha is modulated by estrogen status and related to endothelial function and endothelial nitric oxide synthase in healthy women

CONTEXT AND OBJECTIVE

Estrogen receptor alpha (ER alpha), a potent transcription factor expressed in vascular endothelial cells, plays a key role in regulating vascular function and health. We determined whether vascular endothelial cell expression of ER alpha is influenced by estrogen status and is related to vascular endothelial function in healthy women.

METHODS

ER alpha protein expression was measured (quantitative immunofluorescence) in endothelial cells from peripheral veins of 16 healthy, premenopausal women during the early follicular (EF) and late follicular (LF) phases of the menstrual cycle and 17 estrogen-deficient postmenopausal women. Endothelial-dependent dilation (EDD; brachial artery flow-mediated dilation) and endothelial nitric oxide synthase (eNOS) expression and activation were also measured in a subgroup of women.

RESULTS

In premenopausal women (n = 10), ER alpha expression was 30% lower (P < 0.001) during the EF (low estrogen) compared with the LF (high estrogen) phase of the menstrual cycle. In postmenopausal women, ER alpha expression was 33% lower (P < 0.001) compared with the LF phase of the menstrual cycle in premenopausal women. ER alpha expression was strongly related (r = 0.67; P < 0.001) to EDD, which was reduced in postmenopausal women. ER alpha abundance was positively related to expression of eNOS (r = 0.54; P = 0.009; n = 21) and ser1177 phosphorylated eNOS (r = 0.59; P = 0.006; n = 20).

CONCLUSIONS

These results provide the first evidence that expression of ER alpha in vascular endothelial cells is modulated by estrogen status and may be a key determinant of vascular endothelial function in healthy pre- and postmenopausal women. ER alpha expression may influence vascular endothelial function in women by affecting protein levels and activation of eNOS.

Estrogen and mechanisms of vascular protection

Estrogen has antiinflammatory and vasoprotective effects when administered to young women or experimental animals that appear to be converted to proinflammatory and vasotoxic effects in older subjects, particularly those that have been hormone free for long periods. Clinical studies have raised many important questions about the vascular effects of estrogen that cannot easily be answered in human subjects. Here we review cellular/molecular mechanisms by which estrogen modulates injury-induced inflammation, growth factor expression, and oxidative stress in arteries and isolated vascular smooth muscle cells, with emphasis on the role of estrogen receptors and the nuclear factor-kappaB (NFkappaB) signaling pathway, as well as evidence that these protective mechanisms are lost in aging subjects.

Need for research on estrogen receptor function: importance for postmenopausal hormone therapy and atherosclerosis

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in men and women worldwide. Although rare in premenopausal women, its incidence rises sharply after menopause, indicating atheroprotective effects of endogenous estrogens.

OBJECTIVE

This review discusses the differential effects of estrogen receptor function on atherosclerosis progression in pre- and postmenopausal women, including aspects of gender differences in vascular physiology of estrogens and androgens.

METHODS

Recent advances in the understanding of the pathogenesis of atherosclerosis, estrogen receptor function, and hormone therapy are reviewed, with particular emphasis on clinical and molecular issues.

RESULTS

Whether hormone therapy can improve cardiovascular health in postmenopausal women remains controversial. Current evidence suggests that the vascular effects of estrogen are affected by the stage of reproductive life, the time since menopause, and the extent of subclinical atherosclerosis. The mechanisms of vascular responsiveness to sex steroids during different stages of atherosclerosis development remain poorly understood in women and men.

CONCLUSION

In view of the expected increase in the prevalence of atherosclerotic vascular disease worldwide due to population aging, research is needed to determine the vascular mechanism of endogenous and exogenous sex steroids in patients with atherosclerosis. Such research may help to define new strategies to improve cardiovascular health in women and possibly also in men.

17Beta-estradiol increases basal but not bradykinin-stimulated release of active t-PA in young postmenopausal women

Angiotensin-converting enzyme inhibition potentiates basal and bradykinin-stimulated tissue-type plasminogen activator (t-PA) release to a greater extent in women than in men. This study tested the hypothesis that 17beta-estradiol enhances the effect of angiotensin-converting enzyme inhibition on t-PA release in young postmenopausal women. We conducted a double-blind, prospective, crossover study in 14 young postmenopausal women (mean age 48.2+/-2.3 years) who were randomized to receive 17beta-estradiol (1 mg/d) or matching placebo for 4 weeks. At the end of each treatment period, we measured the effect of intraarterial infusion of bradykinin, methacholine, and nitroprusside on forearm blood flow and net t-PA release, before and during intraarterial enalaprilat (0.33 microg/min/100 mL forearm volume). 17Beta-estradiol significantly reduced baseline venous plasminogen activator inhibitor-1 antigen (4.4+/-1.4 versus 10.4+/-2.5 ng/mL, P=0.001) and t-PA antigen (5.5+/-0.6 versus 7.5+/-1.3 ng/mL, P=0.022) compared with placebo. 17Beta-estradiol increased basal forearm vascular release of active t-PA compared with placebo (1.2+/-0.3 IU/mL/min versus 0.4+/-0.1 IU/mL/min respectively, P=0.032), without increasing t-PA antigen release (P=0.761). Enalaprilat significantly increased basal net t-PA antigen release (from -0.8+/-1.0 to 3.2+/-1.2 ng/min/100 mL, P=0.012), but not the release of active t-PA, during either placebo or 17beta-estradiol. Enalaprilat potentiated bradykinin-stimulated vasodilation and t-PA antigen and activity release similarly during placebo and 17beta-estradiol treatment. 17Beta-estradiol treatment does not alter the effect of angiotensin-converting enzyme inhibition on basal t-PA antigen or on bradykinin-stimulated t-PA antigen or activity release. 17Beta-estradiol increases basal release of active t-PA in young postmenopausal women, consistent with enhanced vascular fibrinolytic function.

Distinct roles of estrogen receptors alpha and beta mediating acute vasodilation of epicardial coronary arteries

This study investigated the contribution of estrogen receptors (ERs) alpha and beta for epicardial coronary artery function, vascular NO bioactivity, and superoxide (O(2)(-)) formation. Porcine coronary rings were suspended in organ chambers and precontracted with prostaglandin F(2alpha) to determine direct effects of the selective ER agonists 4,4',4''-(4-propyl-[(1)H]pyrazole-1,3,5-triyl)tris-phenol (PPT) or 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN) or the nonselective ER agonist 17beta-estradiol. Indirect effects on contractility to U46619 and relaxation to bradykinin were assessed and effects on NO, nitrite, and O(2)(-) formation were measured in cultured cells. Within 5 minutes, selective ERalpha activation by PPT, but not 17beta-estradiol or the ERbeta agonist DPN, caused rapid, NO-dependent, and endothelium-dependent relaxation (49+/-5%; P<0.001 versus ethanol). PPT also caused sustained endothelium- and NO-independent vasodilation similar to 17beta-estradiol after 60 minutes (72+/-3%; P<0.001 versus ethanol). DPN induced endothelium-dependent NO-independent relaxation via endothelium-dependent hyperpolarization (40+/-4%; P<0.01 versus ethanol). 17beta-Estradiol and PPT, but not DPN, attenuated the responses to U46619 and bradykinin. All of the ER agonists increased NO and nitrite formation in vascular endothelial but not smooth muscle cells and attenuated vascular smooth muscle cell O(2)(-) formation (P<0.001). ERalpha activation had the most potent effects on both nitrite formation and inhibiting O(2)(-) (P<0.05). These data demonstrate novel and differential mechanisms by which ERalpha and ERbeta activation control coronary artery vasoreactivity in males and females and regulate vascular NO and O(2)(-) formation. The findings indicate that coronary vascular effects of sex hormones differ with regard to affinity to ERalpha and ERbeta, which will contribute to beneficial and adverse effects of hormone replacement therapy.