Controversial issues in climacteric medicine I. Cardiovascular disease and hormone replacement therapy. International Menopause Society Expert Workshop. 13-16 October 2000, royal society of medicine, London, UK

Studies to Elucidate the Effects of Furostanol Glycosides from Dioscorea deltoidea Cell Culture in a Rat Model of Endothelial Dysfunction

Currently, there is no doubt surrounding a theory that the cardiotropic effects of sex hormones can be due to their direct effect on the cardiovascular system. In recent years, interest in the study of steroid glycosides has increased. We studied the effects of furostanol glycosides (protodioscin and deltozid) from the cell culture of the Dioscorea deltoidea (laboratory code DM-05) on the physiological and biochemical parameters of vascular endothelial function in hypoestrogen-induced endothelial dysfunction after bilateral ovariectomy. It was shown that the use of DM-05 at a dose of 1 mg/kg makes it possible to prevent the development of arterial hypertension (the level of systolic blood pressure (SBP) decreases by 9.7% (p < 0.05) and diastolic blood pressure (DBP) by 8.2%), to achieve a decrease in the coefficient of endothelial dysfunction by 1.75 times against the background of a hypoestrogenic state. With DM-05, an increase in the concentration of stable nitric oxide metabolites (NOx) by 45.6% (p < 0.05) and an increase in mRNA endothelial nitric oxide synthase (eNOS) expression by 34.8% (p < 0.05) was established, which indicates a positive effect of furostanol glycosides on the metabolism of nitric oxide after ovariectomy. Positive dynamics in the histological structure of the heart and the abdominal aorta indicate the pronounced endothelio- and atheroprotective effects of DM-05.

Influence of body weight on the biochemical indicators in menopause

Introduction:

One of the problems of today and probably this century is obesity, which is classified by the WHO as a disease.

Material and methods:

We performed a prospective cross-sectional study of the body weight impact on certain biochemical indicators in menopausal women living in the municipalities Cazin and Velika Kladusa.

Results and discussion:

The study included 334 women aged 40-60 years, who had regular medical examinations. For each patient at the beginning of the study we measured: body mass index, total cholesterol values, LDL, HDL and triglycerides fractions. Our findings indicate an increase in total cholesterol, LDL fraction and triglycerides in patients with increased body mass index, without statistical significance. Values of HDL fraction were significantly decreased with increasing body mass index.

Short-term effects of low-dose estrogen/drospirenone vs low-dose estrogen/dydrogesterone on glycemic fluctuations in postmenopausal women with metabolic syndrome

This study aims to compare the effects of low-dose emidrate estradiol/drospirenone (E2/DRSP) vs low-dose emidrate estradiol/dydrogesterone (E2/DG) combination on the mean amplitude of glycemic excursions (MAGE) value in postmenopausal women affected by metabolic syndrome (MS). One hundred sixty postmenopausal women were recruited to receive a treatment with oral doses of E2/1 mg plus drospirenone/2 mg (E2/DRSP group) or oral dose of E2/1 mg plus dydrogesterone/5 mg (E2/DG group) for 6 months. At enrollment and after 6 months, anthropometric, metabolic, and inflammatory parameters have been assessed. MAGE, evaluated during 48-h continuous subcutaneous glucose monitoring (CSGM), allowed us to assess daily glucose fluctuations at baseline and after 6 months. After hormone therapy, both groups showed a significant decline in fasting plasma glucose levels (p < 0.05), while only E2/DRSP group showed a statistically significant decline in waist circumferences, post-prandial glycemia, LDL, plasma triglycerides, MAGE, HOMA index, and plasma IL-6 (p < 0.05) levels. In the whole population (n = 160), after 6 months of indicated therapy, changes in fasting plasma glucose and PAI-1 levels correlated with the changes in MAGE values, while only in E2/DRSP group that MAGE reduction was positively associated with a stronger decrease in waist circumferences, triglycerides, and TNF-α plasma levels. The independent effect of hormone therapy (HT) on reduction in MAGE value has been tested in three different multiple linear regression models. HT resulted to be associated with MAGE, independent of other confounding variables. Although both groups had a decline in fasting plasma glucose, only drospirenone treatment revealed positive effects on glycemic excursions and insulin sensitivity, induced favorable changes in lipid profile, and showed an improvement of inflammatory indices in postmenopausal women with MS.

Black cohosh (Actaea racemosa) for the mitigation of menopausal symptoms: recent developments in clinical safety and efficacy

The purpose of this article is to assess recent data supporting the safety and efficacy of black cohosh products for the mitigation of menopause-related symptoms. Searches of the published literature in Napralert, Cochrane Library and PubMed databases were performed from 2003 to 2006. Information from drug regulatory agencies from five different countries was obtained to evaluate safety. While there are a few contradictory studies, the majority of the clinical trials indicate that extracts of black cohosh (Actaea racemosa L.) improve menopause-related symptoms. However, to date, at least 50 cases of possible hepatotoxicity have been reported. Although previous safety reviews suggest that black cohosh is well tolerated, the increasing numbers of these case reports indicates that further preclinical toxicological evaluations of black cohosh are urgently needed. At this time, it appears prudent to advise menopausal women with underlying liver disease, autoimmune diseases or those taking medications that may impact liver function not to use products containing black cohosh.

Managing menopausal symptoms after gynecological cancer

PURPOSE OF REVIEW

As the length of survival in patients with gynecological malignancies increases due to advances in early diagnosis and therapy, quality of life becomes a major issue for the survivors. These women frequently suffer symptoms following an iatrogenically induced menopause. Many gynecologists advise these patients against hormonal replacement therapy. This review attempts to provide the clinician with information based on current evidence.

RECENT FINDINGS

The most recent two prospective studies did not find an increase in the recurrence rates in endometrial cancer patients who used hormonal replacement therapy. To date, there are few studies on hormonal replacement therapy in patients with ovarian cancer but the available data suggest that there is no detriment to overall or disease-free survival. There are no data showing an association between poorer outcome and hormonal replacement therapy use in patients with cervical or vulvar cancers.

SUMMARY

There is no evidence showing hormones negatively influence survival after treatment for epithelial ovarian, squamous cervical or vulvar cancer. Their use can be considered in symptomatic patients with endometrial cancer, after weighing the benefits against the risk of recurrence. Gynecologic cancer survivors suffering from menopausal symptoms should be supported by advice about the alternatives to hormonal replacement therapy and by giving them nonbiased information on the present knowledge on the effects of hormonal use in women with a previous cancer. It is reasonable to prescribe hormonal replacement therapy to symptomatic, well informed patients.

1 and 2 mg 17β-estradiol combined with sequential dydrogesterone have similar effects on the serum lipid profile of postmenopausal women

OBJECTIVES

The aim of this study was to assess the effects of 1 and 2 mg 17beta-estradiol on serum lipid profile. Beneficial effects have been clearly established in previous studies with a 2 mg dose; further evidence was required to confirm the beneficial effects of a 1 mg dose.

METHODS

This double-blind, placebo-controlled study involved 579 postmenopausal women randomized to oral treatment with placebo, 1 mg/day 17beta-estradiol sequentially combined with 5 or 10 mg/day dydrogesterone for the last 14 days of each 28-day cycle, or 2 mg/day 17beta-estradiol sequentially combined with 10 or 20 mg/day dydrogesterone for the last 14 days of each 28-day cycle. Treatment was continued for 26 cycles.

RESULTS

High density lipoprotein (HDL) cholesterol levels were significantly (p<0.05) increased after 26 cycles in all active treatment groups compared with placebo. In addition, low density lipoprotein (LDL) cholesterol and lipoprotein(a) levels were significantly reduced, and apolipoprotein A1 and triglyceride levels were significantly increased, in all active treatment groups after 13 and 26 cycles.

CONCLUSIONS

The results of this study clearly indicate that sequential combinations of either 1 or 2 mg 17beta-estradiol with dydrogesterone are associated with long-term, favorable changes in the serum lipid profile. There was no evidence that dydrogesterone compromised the 17beta-estradiol-induced improvements in lipid profile.

The effect of chinese medicinal herbs in relieving menopausal symptoms in ovariectomized chinese women

OBJECTIVE

The aim of this study was to explore the effect of a defined formula of Chinese medicinal herbs, GengNianAn (GNA, also called menopausal symptom-relieving formula) formula in relieving menopausal symptoms in ovariectomized women.

DESIGN

A double-blind randomized placebo-controlled trial.

METHOD

Between May 2003 and June 2006, 69 ovariectomized Chinese women were recruited to complete 12 weeks of intervention with either a defined formula of GNA (n = 36) or placebo (n = 33) taken twice daily as a beverage. Clinical symptoms were assessed by the modified Kupperman scale. The levels of venous blood serum follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E(2)), and the maturation index (MI) of vaginal epithelial cells were respectively measured.

RESULTS

There existed significant differences between the two groups in the total Kupperman scoring, MI of vaginal exfoliative cells, and the levels of FSH, LH, and E(2) after treatment (P < .05).

CONCLUSION

Chinese herbs may be a useful alternative treatment for ovariectomized women suffering from menopausal symptoms, who are unable or do not want to receive hormone replacement therapy (HRT).

Black cohosh (Actaea/Cimicifuga racemosa): review of the clinical data for safety and efficacy in menopausal symptoms

Since the publication of the results of the Women's Health Initiative that described the risks of hormone replacement therapy, many women are actively seeking alternative treatments for menopausal symptoms. Black cohosh (Actaea racemosa, syn. Cimicifuga racemosa) is one such alternative that has been used in the US for over 100 years. To date only two cimicifuga extracts have been tested clinically, and the current recommended dosage is 40-80 mg/day. Review of the published clinical data suggests that cimicifuga may be useful for the treatment of menopausal symptoms, such as hot flashes, profuse sweating, insomnia, and anxiety. However, the methodology used in most of the trials is poor and further clinical assessment of cimicifuga is needed. In terms of safety, transient adverse events such as nausea, vomiting, headaches, dizziness, mastalgia, and weight gain have been observed in clinical trials. A few cases of hepatotoxicity have been reported, but a direct association with the ingestion of cimicifuga has not been demonstrated. The most recent data suggest that cimicifuga is not estrogenic.

Hormone replacement therapy in cancer survivors

OBJECTIVE

Thousands of women are treated each year for cancer; many of these are already in menopause, while other younger patients will go into early menopause due to surgery, or chemotherapy, or the need for radiotherapy to the pelvic region. In most cases the oncologist and the gynaecologist would advise these women against the use of HRT. The purpose of this paper is to review biological and clinical evidences in favour and against HRT use in the different tumours and to propose an algorithm that can help choosing the treatment for the single woman.

METHODS

We performed a systematic literature review through April 2002 concerning: (1) biological basis of hormonal modulation of tumour growth; (2) epidemiological data on the impact of HRT on different cancers risk in healthy women; (3) safety of HRT use in cancer survivors; (4) alternatives to HRT.

RESULTS

With the exception of meningioma, breast and endometrial cancer, there is no biological evidence that HRT may increase recurrence risk. In women with previous breast and endometrial cancer HRT is potentially hazardous on a biological basis, even if published data do not show any worsening of prognosis.

CONCLUSIONS

Even if a cautious approach to hormonal-dependent neoplasias is fully comprehensible and the available alternative treatment should be taken into greater consideration, the reticence to prescribe HRT in women previously treated for other non hormone-related tumours has neither a biological nor a clinical basis. An algorithm based on present knowledge is proposed.

Impaired high density lipoprotein antioxidant activity in healthy postmenopausal women

The high incidence of atherosclerosis in women after menopause is associated with a risk pattern including an increase in low density lipoprotein (LDL), even though high density lipoprotein (HDL) cholesterol levels tend to be maintained or slightly decreased. Since estrogens are considered potent antioxidants, an increase in lipid peroxidation and formation of reactive oxygen species would be expected after menopause. If HDL becomes oxidized, the ability to protect LDL against oxidation may be impaired. In postmenopausal women there are scarce reports concerning HDL oxidability and no data about its antioxidant activity. We studied copper-induced oxidation and conjugated dienes formation in HDL isolated from 58 women, 30 postmenopausal (PMW) and 28 premenopausal (PreMW). None presented diabetes or cardiovascular disease and none was receiving hormonal, hypolipidemic or antioxidant therapy either. In order to evaluate the effect of HDL on LDL oxidation we isolated LDL and HDL from the same subject and assessed copper-induced LDL oxidation in the presence of HDL, followed by thiobarbituric acid-reactive substances determination. Relationships with HDL chemical composition, alpha-tocopherol content, cholesteryl ester transfer protein (CETP) and paraoxonase activity (PON) were investigated. HDL chemical composition in PMW exhibited triglyceride enrichment when compared to PreMW (p <0.05). alpha-Tocopherol content and CETP activity were similar in both groups. However, CETP activity correlated positively with HDL triglyceride and negatively with HDL cholesterol percentage (r=0.44, p <0.01 and r=-0.32, p <0.05, respectively). Paraoxonase activity did not show differences between PMW and PreMW. When evaluating HDL oxidability, PMW revealed a shorter lag time in comparison to PreMW, even after adjustment for age, p <0.05. Moreover, when the effect of HDL on LDL oxidation was evaluated, HDL from PMW showed a reduction in its ability to inhibit LDL oxidation, compared to PreMW (p <0.05). In addition, the extent of inhibition of LDL oxidation by HDL was positively correlated with HDL resistance to oxidation (r=0.27, p <0.05). After women classification by paraoxonase phenotype, HDL ability to protect LDL against oxidation remained reduced only in PMW belonging to the PON QR phenotype, in comparison to PreMW QR. These results suggest that HDL from PMW exhibits impairment in its antioxidant ability, which is associated to a decreased HDL resistance to oxidation. In turn, this was related to triglyceride enrichment of HDL particles. All these alterations were independent from HDL cholesterol plasma levels.

In vitro effects of progesterone and progestins on vascular cells

The impact of progesterone on the cardiovascular system is relevant, but not as well characterized as the effects of estrogens. The recent early interruption of the conjugated equine estrogens (CEE)-medroxyprogesterone acetate (MPA) arm of the Women's Health Initiative trial, but not of the parallel CEE-only treatment arm, suggesting the possibility of harmful cardiovascular effects of the progestins, boosts the debate on the role of progesterone and progestins on the vascular tree. The data available up to now show the presence of important regulatory effects of progestagens on vascular cells. Additionally, the presence of a progestagen results in diverse modifications of the effects of estrogens, sometimes acting synergically, others being neutral or antagonizing estrogens' effects. Notwithstanding the availability of consistent observations on the functional effects of progestins on the cardiovascular system, the molecular mechanisms of progestins actions on vascular cells have been up to now only scarcely characterized. Novel mechanisms of signal transduction are being discovered for progesterone receptors in different tissues, some of which are independent of gene transcription regulation, and are therefore indicated as "nongenomic." Furthermore, the contribution to signal transduction of co-activators is currently widely investigated, in order to understand the ways to tissue-specificity and to engineer new progesterone receptor modulators. The understanding of the molecular basis of progesterone receptor signaling in vascular tissue is therefore of paramount importance for the development of hormonal agents with an optimal cardiovascular profile.

The effects of soy protein containing isoflavones on lipids and indices of bone resorption in postmenopausal women

OBJECTIVE

To assess the effect of a dietary soy protein supplement containing isoflavones on lipids and indices of bone resorption in postmenopausal women.

DESIGN

Placebo-controlled, double-blind, randomized study.

PATIENTS

One hundred and six postmenopausal women were randomized to dietary soy supplementation (n = 51) or placebo (n = 55) for 3 months, of which 78 were included in the final analysis.

MEASUREMENTS

Lipid profiles including total, low-density lipoprotein (LDL) and HDL cholesterol as well as triacylglycerol were measured. Pyridinoline and deoxypyridinoline were used as markers of bone resorption. Urinary isoflavone excretion was measured to assess compliance.

RESULTS

There was a significantly greater increase in urinary isoflavone excretion detected in the soy group compared to placebo. Lipid profiles improved with significant decreases in LDL cholesterol (-0.60 +/- 0.10 vs.-0.29 +/- 0.09 mmol/l, P < 0.05), triacylglycerol (-0.22 +/- 0.07 vs. +0.01 +/- 0.05 mmol/l, P < 0.005) and the LDL : HDL ratio (-0.32 +/- 0.10 vs. +0.20 +/- 0.10, P < 0.005) in the soy group compared to placebo. There were no significant differences between the soy and placebo groups for urinary excretion of pyridinoline (-3.8 +/- 3.1 vs.-0.8 +/- 3.1 nmol/mmolCr, P = 0.4) or deoxypyridinoline (-0.8 +/- 0.9 vs.-0.3 +/- 0.7 nmol/mmolCr, P = 0.4).

CONCLUSIONS

In postmenopausal women, dietary supplementation with soy protein containing isoflavones does not appear to have oestrogenic effects on markers of bone resorption. Soy protein favourably affected lipids; however, these effects (fall in triacylglycerol and no change in HDL) differ from those observed with oral oestrogen. These findings suggest that soy may not have biologically significant oestrogenic effects on bone resorption and we hypothesize that the lipid effects may be mediated, at least in part, through nonoestrogenic mechanisms.

Menopause after breast cancer: a survey on breast cancer survivors

Due to the younger age and the ever wider use of adjuvant chemotherapy and antiestrogens, menopausal symptoms are a frequent cause of concern for breast cancer patients.

OBJECTIVES

To determine the prevalence of menopausal symptoms, and to explore the attitudes toward Hormone Replacement Therapy (HRT) or other treatments and the willingness to take oestrogen in breast cancer patients.

METHODS

A questionnaire-based survey on 250 breast cancer patients treated and followed-up at our department. Of them 144 (Group A) were in postmenopause and 106 (Group B) were in premenopause at time of diagnosis.

RESULTS

Adjuvant therapy with tamoxifen or tamoxifen plus chemotherapy is associated with a significant worsening of menopause-related symptoms of women belonging to Group A. These women are more concerned about risk of breast cancer recurrence than about risk of osteoporosis (P=0.05) and heart disease (P=0.006). Seventy-eight percent are against the use of HRT; only 22% would consider taking HRT mainly for vasomotor symptoms relief and osteoporosis prevention. The incidence of vasomotor and dystrophic symptoms is significantly higher in women belonging to Group B treated with chemotherapy and/or hormonotherapy as compared with postmenopausal women (P<0.000 and P=0.02, respectively). Premenopausal women are more concerned about risk of breast cancer recurrence than older women (P=0.09) and at the same time are significantly more worried about the impairment of the quality of life due to adjuvant therapy (P=0.005). Younger women are more prone to consider HRT than postmenopausal women (P=0.05). Sixty-six percent are against HRT use, and 34% would consider taking HRT to alleviate vasomotor and dystrophic symptoms and to prevent osteoporosis.

CONCLUSIONS

Breast cancer survivors are interested to treatments that may improve their quality of life, but fear of HRT persists among these women and their doctors, despite new evidence suggesting the low probability of detrimental effects.

Botanical dietary supplement use in peri- and postmenopausal women

OBJECTIVE

To determine use of botanical dietary supplements (BDS) in women between the ages of 40 and 60 years at the University of Illinois at Chicago (UIC) clinics, including information about commonly used BDS, the reason for use, information resources used, and the overall perception of safety and efficacy of BDS.

DESIGN

Five hundred female outpatients at UIC clinics were interviewed by healthcare practitioners using a botanical/drug history questionnaire. Respondents were 46.8% African American, 39.6% Caucasian, 11.7% Hispanic, and 1.5% Asian, with a mean age of 50.34 years.

RESULTS

BDS were used by 79% of respondents ( = 395), of which 36.5% used BDS daily. Of the positive respondents, 51.7% used one or two BDS, whereas 48.4% used three or more. Commonly used botanicals included soy (42%), green tea (34.68%), chamomile (20.76%), gingko (20.51%), ginseng (17.97%), Echinacea (15.44%), and St. John's wort (7.34%). Black cohosh, garlic, red clover, kava, valerian, evening primrose, and ephedra were used by less than 15% of respondents. Efficacy ratings were high for BDS, and 68% claimed to have no side effects. Only 3% of respondents obtained BDS information from healthcare professionals, and 70% of respondents were not informing their physician of BDS use.

CONCLUSIONS

A high percentage of women at UIC clinics were using multiple BDS. The respondents believed that these products were both safe and effective for the treatment of common ailments. Concomitant BDS use with prescription and over-the-counter medications was commonplace, often without a physician's knowledge. Consumer education about the possible benefits and risks associated with BDS use is urgently needed.

Conjugated equine estrogens, estrone sulphate and estradiol valerate oral administration in ovariectomized rats: effects on central and peripheral allopregnanolone and beta-endorphin

OBJECTIVES

Several natural or synthetic estrogenic molecules are commonly used in oral hormone replacement therapy for the relief of menopausal complaints and for the primary prevention of cardiovascular disease and osteoporosis. Little information is available concerning the comparative efficacy of different compounds on neuroendocrine function. The opioid peptide beta-endorphin (beta-EP), and the neurosteroid allopregnanolone are considered markers of neuroendocrine function and their synthesis and action is regulated by gonadal steroids. The present study aimed to investigate the effects of a 2-week oral treatment with estradiol valerate (EV), estrone sulphate (ES), or conjugated equine estrogen (CEE) on central and peripheral beta-EP and allopregnanolone levels in ovariectomized (OVX) female rats.

METHODS

Twelve groups of Wistar OVX rats received oral EV (0.05, 0.1, 0.5 and 1 mg/Kg/day) or ES (0.1, 0.5, 1 and 2 mg/Kg/day), or CEE (0.1, 0.5, 1 and 2 mg/Kg/day) for 14 days. One group of fertile and one group of OVX rats were used as controls. beta-EP content was assessed in hypothalamus, hippocampus, anterior and neurointermediate pituitary, and plasma, while allopregnanolone content was assessed in hypothalamus, hippocampus, anterior pituitary, adrenals and serum.

RESULTS

Ovariectomy induced a significant decrease in beta-EP and allopregnanolone content in hypothalamus, hippocampus, pituitary, and serum, while it increased allopregnanolone content in the adrenals. In OVX rats, the administration of each molecule reversed the ovariectomy-induced beta-EP and allopregnanolone changes in a dose-dependent fashion, therefore completely restoring their concentration. At higher doses, the estrogenic compounds induced significantly higher levels of allopregnanolone and beta-EP than in fertile rats. CEE induced higher allopregnanolone levels in hypothalamus, anterior pituitary and serum than the other estrogenic molecules, and in the hippocampus with respect to EV alone. CEE produced higher beta-EP levels in the hippocampus and hypothalamus with respect to EV and ES.

CONCLUSION

In the examined tissue and serum estrogens restore the ovariectomy induced changes in allopregnanolone and beta-EP content in a dose-dependent manner; the magnitude of these effects is not uniform and it is related to the different tissues and the employed compounds.

Black cohosh: an alternative therapy for menopause?

Due to the long-term health risks now associated with hormone replacement therapy, many menopausal women are actively seeking alternative treatments. One such alternative is black cohosh (Actaea racemosa, syn. Cimicifuga racemosa), which has been used in the United States for the treatment of gynecologic complaints for more than 100 years. Review of the published clinical data suggests that black cohosh may be useful for the treatment of menopausal symptoms, such as hot flashes, profuse sweating, insomnia, and anxiety. Results from the most recently published trial, however, indicate that black cohosh is not effective for the treatment of menopausal symptoms in breast cancer survivors being treated with tamoxifen. Because the overall quality of the published clinical trials is low, two new randomized, double-blind, placebo-controlled clinical trials are currently underway in the United States. To date, only one standardized black cohosh extract has been tested clinically; the current recommended dose is 40-80 mg per day. At least 4-12 weeks of treatment may be required before any therapeutic benefits may be apparent. Adverse reactions such as nausea, vomiting, headaches, dizziness, mastalgia, and weight gain have been observed in clinical trials. No drug interactions are reported in the medical literature. The estrogenic effects of black cohosh are controversial, and the more recent data indicate that black cohosh extracts may have an anti-estrogenic activity. Owing to potential effects on sex hormones, however, black cohosh should not be administered to children or during pregnancy and lactation.

Genomic and nongenomic mechanisms of nitric oxide synthesis induction in human endothelial cells by a fourth-generation selective estrogen receptor modulator

Cardiovascular disease is the leading cause of morbidity and mortality in postmenopausal women. EM-652 (acolbifene) is a fourth-generation selective ER modulator (SERM) exerting complete antiestrogenic effects on the breast and uterus. EM-652 potently inhibits bone resorption and induces positive lipid modifications in estrogen-deficient animals. As most of the cardioprotective actions of estrogen are exerted directly at the vascular level, we studied the effects of EM-652 on endothelial production of nitric oxide (NO) in vitro and in vivo. EM-652 triggers NO release by human umbilical vein endothelial cells through nongenomic mechanisms, rapidly activating endothelial nitric oxide synthase (eNOS) via an ER-dependent sequential activation of MAPKs and PI3K/Akt pathways independently from gene transcription or protein synthesis. Moreover, EM-652 increases eNOS protein levels during prolonged treatments. Upon pharmacological comparison, EM-652 is markedly more potent than the SERMs raloxifene and tamoxifen in increasing NO synthesis from endothelial cells. In ovariectomized and fertile rats, EM-652 increases aortic eNOS expression and enzymatic activity at low, but not at higher, dosages. The present data show that EM-652 (acolbifene) has estrogen-like activity on the vascular wall, directly increasing NO production through genomic and nongenomic mechanisms in vitro and in vivo.

Nongenomic mechanisms of endothelial nitric oxide synthase activation by the selective estrogen receptor modulator raloxifene

BACKGROUND

Nontranscriptional signaling through estrogen receptors (ERs) is important in the cardiovascular system. In particular, estrogen stimulates endothelial NO synthase (eNOS) via the phosphatidylinositol 3-kinase (PI3K) pathway. The selective estrogen receptor modulator (SERM) raloxifene is effective for the treatment of postmenopausal osteoporosis, but its ability to activate eNOS via PI3K is unknown.

METHODS AND RESULTS

Human umbilical vein endothelial cells were cultured in estrogen-deprived, phenol red-free medium. Raloxifene stimulated eNOS in a concentration- and time-dependent manner. Activation of eNOS by raloxifene was blocked by the PI3K inhibitor wortmannin and by the ER antagonist ICI 182,780 but not by transcriptional or translational inhibitors. Coimmunoprecipitation studies demonstrated that, in a ligand-dependent manner, raloxifene increased ERalpha-associated p85alpha, p110alpha, and PI3K activity. This correlated temporally with increases in the serine and threonine phosphorylation and activation of protein kinase Akt.

CONCLUSIONS

Our findings indicate that nongenomic ER signaling triggered by a SERM leads to a rapid activation of NO synthesis in human endothelial cells. The ability of raloxifene to facilitate ERalpha-PI3K interaction may provide additional insight into the structure-function relationship of specific SERMs, which promote the nontranscriptional effects of ER.

Reciprocal antagonism between estrogen receptor and NF-kappaB activity in vivo

The functional interaction, or "cross-talk," between estrogen receptor (ER) and the proinflammatory transcription factor nuclear factor (NF)-kappaB demonstrated in vitro has been suggested to play a role in estrogen prevention of cardiovascular disease. Here, we demonstrate that this reciprocal cross-talk occurs in vivo. Ovariectomized C57BL/6 mice fed an atherogenic diet had increased hepatic levels of active NF-kappaB and numerous inflammatory genes, including MHC invariant chain (Ii), vascular cell adhesion molecule-1, tumor necrosis factor-alpha, and RANTES. Treatment with 17alpha-ethinylestradiol (EE) strongly blocked induction of these genes but had no effect on their basal expression levels. ER was required for this activity, because the antagonist ICI 182,780 completely blocked the inhibitory activity of EE. Gene activation by EE was not required for inhibition of inflammatory gene expression, because both the phytoestrogen genistein and low doses of EE were effective in blocking inflammatory gene induction without inducing marker genes such as intestinal trefoil factor (ITF) or myo-inositol-1-phosphate synthase (IPS). The in vivo transcriptional interference was reciprocal, with EE induction of ITF and IPS greatly reduced in animals fed the atherogenic diet versus chow-fed controls. This interference was specific to the liver, because diet had no effect on uterine weight increases produced by EE. Transfection experiments confirmed that the extent of inhibition of ER-mediated transcription by inflammatory stimuli correlated with the extent of NF-kappaB activation. These results suggest that the cross-talk between ER and NF-kappaB does occur in vivo and may indeed contribute significantly to the cardioprotective effects of estrogen.