Can a healthy endothelium influence the cardiovascular effects of hormone replacement therapy?

Cerebrovascular Hemodynamics in Women

Sex and gender, as biological and social factors, significantly influence health outcomes. Among the biological factors, sex differences in vascular physiology may be one specific mechanism contributing to the observed differences in clinical presentation, response to treatment, and clinical outcomes in several vascular disorders. This review focuses on the cerebrovascular bed and summarizes the existing literature on sex differences in cerebrovascular hemodynamics to highlight the knowledge deficit that exists in this domain. The available evidence is used to generate mechanistically plausible and testable hypotheses to underscore the unmet need in understanding sex-specific mechanisms as targets for more effective therapeutic and preventive strategies.

Estrogen receptor β-dependent Notch1 activation protects vascular endothelium against tumor necrosis factor α (TNFα)-induced apoptosis

Unlike age-matched men, premenopausal women benefit from cardiovascular protection. Estrogens protect against apoptosis of endothelial cells (ECs), one of the hallmarks of endothelial dysfunction leading to cardiovascular disorders, but the underlying molecular mechanisms remain poorly understood. The inflammatory cytokine TNFα causes EC apoptosis while dysregulating the Notch pathway, a major contributor to EC survival. We have previously reported that 17β-estradiol (E2) treatment activates Notch signaling in ECs. Here, we sought to assess whether in TNFα-induced inflammation Notch is involved in E2-mediated protection of the endothelium. We treated human umbilical vein endothelial cells (HUVECs) with E2, TNFα, or both and found that E2 counteracts TNFα-induced apoptosis. When Notch1 was inhibited, this E2-mediated protection was not observed, whereas ectopic overexpression of Notch1 diminished TNFα-induced apoptosis. Moreover, TNFα reduced the levels of active Notch1 protein, which were partially restored by E2 treatment. Moreover, siRNA-mediated knockdown of estrogen receptor β (ERβ), but not ERα, abolished the effect of E2 on apoptosis. Additionally, the E2-mediated regulation of the levels of active Notch1 was abrogated after silencing ERβ. In summary, our results indicate that E2 requires active Notch1 through a mechanism involving ERβ to protect the endothelium in TNFα-induced inflammation. These findings could be relevant for assessing the efficacy and applicability of menopausal hormone treatment, because they may indicate that in women with impaired Notch signaling, hormone therapy might not effectively protect the endothelium.

Effect of hormone replacement therapy with the anti-mineralocorticoid progestin Drospirenone compared to tibolone on endothelial function and central haemodynamics in post-menopausal women

Drospirenone (DRSP) is an antialdosterone agent with progestogenic and antiandrogenic effects. This compound, has been recently used in combination with 17β-estradiol (E2) as hormonal therapy in postmenopausal women and has been shown to exert a significant antihypertensive effect in hypertensive post-menopausal women. Aim of the present study was to compare the effect of DRSP/E2 with those of Tibolone (T) on endothelial function, arterial stiffness, and lipid profile of early postmenopausal women naïve on post-menopausal hormonal therapy. Twenty-four women met the inclusion criteria and entered the study. Women were randomized to receive either DRSP/E2 or T for 6months. Blood pressure and heart rate were similar in both groups at baseline and at the end of the study. Compared to baseline, endothelial function assessed by Reactive Hyperemia (RH) significantly improved in women receiving E2/DRSP, whereas no significant differences between baseline and follow up were detected in women receiving Tibolone. Women receiving E2/DRSP showed a significant decrease in pulse wave velocity and Augmentation Index compared to baseline while no changes were observed in women receiving Tibolone. The capacity of sera to trigger endothelial cells apoptosis in vitro measured by cell death assay was significantly reduced by E/DRSP but not by T (HFA-E 70±5,6% vs HFD-E 41±4,5%, p<0,001). In conclusion, the present study shows that the association of Estradiol and Drospirenone as hormonal replacement therapy significantly improves vascular parameters and the composition of sera relevant for vascular protection in early post-menopausal normotensive women. These effects are not shared by Tibolone.

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.

Progesterone enhances vascular endothelial cell migration via activation of focal adhesion kinase

The mechanisms of progesterone on endothelial cell motility are poorly investigated. Previously we showed that progesterone stimulated endothelial cell migration via the activation of actin-binding protein moesin, leading to actin cytoskeleton remodelling and the formation of cell membrane structures required for cell movement. In this study, we investigated the effects of progesterone on the formation of focal adhesion complexes, which provide anchoring sites for cell movement. In cultured human umbilical endothelial cells, progesterone enhanced focal adhesion kinase (FAK) phosphorylation at Tyr(397) in a dose- and time-dependent manner. Several signalling inhibitors interfered with progesterone-induced FAK activation, including progesterone receptor (PR) antagonist ORG 31710, specific c-Src kinase inhibitor PP2, phosphatidylinosital-3 kinase (PI3K) inhibitor wortmannin as well as ρ-associated kinase (ROCK-2) inhibitor Y27632. It suggested that PR, c-Src, PI3K and ROCK-2 are implicated in this action. In line with this, we found that progesterone rapidly promoted c-Src/PI3K/Akt activity, which activated the small GTPase RhoA/ρ-associated kinase (ROCK-2) complex, resulting in FAK phosphorylation. In the presence of progesterone, endothelial cells displayed enhanced horizontal migration, which was reversed by small interfering RNAs abrogating FAK expression. In conclusion, progesterone promotes endothelial cell movement via the rapid regulation of FAK. These findings provide new information on the biological actions of progesterone on human endothelial cells that are relevant for vascular function.

Hormone therapy and coronary heart disease risk by vasomotor menopausal symptoms

OBJECTIVES

We examined whether the association between hormone therapy (HT) use and coronary heart disease (CHD) risk differed between women with and without vasomotor symptoms (VMS).

STUDY DESIGN

We used data from a Dutch (EPOS) and Swedish (WHILA) population-based sample of 8865 women, aged 46-64 years, and free of CHD, stroke, venous thrombosis/pulmonary embolism or cancer at baseline. Data on HT use, VMS and potential confounders were collected by questionnaires.

MAIN OUTCOME MEASURES

CHD endpoints, obtained via registries.

RESULTS

252 CHD cases occurred during 10.3 years of follow-up. Neither for women with nor for women without flushing or (night) sweats ever HT use was associated with CHD risk, compared with never HT use. Among women with intense VMS, ever HT use borderline significantly decreased CHD risk compared with never HT use (HR 0.48 [95% CI 0.20-1.03]). Among women without intense VMS, ever HT use was associated with a borderline significant increased CHD risk (HR 1.28 [95% CI 0.96-1.70]; P for interaction=0.02). However, after multivariate adjustment, as compared to never HT use, ever HT use was not associated with risk of CHD among women with or without intense VMS.

CONCLUSIONS

In both groups of women with and without VMS, HT use does not seem to be associated with the risk of CHD. Hence, our findings do not support the view that HT use increases the CHD risk among women with an indication, i.e. VMS, but this needs to be confirmed in specifically designed studies.

Synthesis and evaluation of nitric oxide-releasing derivatives of 3-n-butylphthalide as anti-platelet agents

Most ischemic stroke results from brain blood vessel blockage by platelet-mediated thrombus, and anti-platelet therapy has been demonstrated clinical benefits in the treatment of this disease. In the present work, novel nitric oxide (NO)-releasing derivatives of an anti-ischemic stroke drug 3-n-butylphthalide (NBP) were synthesized. Compounds 7a and 7c exhibited more potent anti-platelet activity than NBP and aspirin, and released a moderate amount of NO, which is beneficial in improving cardiovascular and cerebral circulation. These findings provide an alternative approach to the development of drugs more potent than NBP for the intervention of ischemic stroke.

Hormone replacement therapy and cardioprotection: a new dawn? A statement of the Study Group on Cardiovascular Disease in Women of the Italian Society of Cardiology on hormone replacement therapy in postmenopausal women

Cardiovascular disease is the leading cause of death in women in Western countries. Despite preventive strategies, in the past decades the incidence of cardiovascular events has shown a decline in men but a rise in women, matching the growth of the population of postmenopausal women. Several epidemiological findings suggest the causative pathophysiological role of ovarian hormone deficiency in the development of cardiovascular disease in women. Observational and randomized studies have suggested that hormone replacement therapy in early postmenopause could be beneficial from a cardiovascular point of view. Conversely, aging, time since menopause and presence of cardiovascular risk factors or cardiovascular disease may decrease its efficacy and increase the risk of cardiovascular events. It is plausible that the unfavorable effects of the estrogen/progestin combination used in the randomized studies are not related to the hormone preparation per se but rather to the use of hormones in the less receptive group of women, older and with cardiovascular risk factors. Clinical judgment, choice of the right dose and estrogen/progestin combination are of pivotal importance to maximize the beneficial effect of estrogen replacement therapy/hormone replacement therapy, especially if given within a reasonable time after the menopause to women who need the therapy for the relief of menopausal symptoms.

Effects in postmenopausal women of estradiol and medroxyprogesterone alone and combined on resistance artery function and endothelial morphology and movement

CONTEXT

Endothelial dysfunction in resistance arteries after menopause is important for the development of high blood pressure and cardiovascular disease.

OBJECTIVES

Our objectives were to study the effects of different hormone replacement therapies on the function and morphology of isolated resistance arteries, and to look for their mechanistic basis.

DESIGN AND SETTING

This was a randomized, placebo-controlled double-blind study in a University hospital, along with laboratory based studies.

PATIENTS AND INTERVENTIONS

We isolated resistance arteries in sc biopsies from 55 postmenopausal women before and after 3-month therapy with estradiol (E2), medroxyprogesterone acetate (MPA), E2 plus MPA, or placebo. In addition, we studied isolated human endothelial cells.

MAIN OUTCOME MEASURES AND RESULTS

Artery flow-mediated dilatation was augmented after treatment with E2 or E2 plus MPA, whereas MPA or placebo had no effect. Pressure-induced myogenic tone was reduced by E2 plus MPA, whereas it was unchanged in the other groups. Scanning microscopy showed that E2 improved endothelial cell morphology and decreased signs of endothelial apoptosis, but the addition of MPA impaired these events. E2, MPA, or the combination all increased the expression and phosphorylation of the actin-binding protein, moesin and of the focal adhesion complex controller, focal adhesion kinase, and induced the rearrangement of cytoskeletal actin and vinculin fibers. All treatments promoted endothelial cell horizontal migration, with E2 inducing the strongest effect.

CONCLUSIONS

This study suggests that hormone replacement therapy with estrogens or in combination with MPA may benefit the function of resistance arteries and may preserve the morphological integrity of endothelial cells by regulatory actions on the cytoskeleton.

More than a decade of estrogen neuroprotection

Considerable evidence has emerged through more than a decade of research supporting the neuroprotective and cognition-preserving effects of estrogens. Such basic research coupled with various epidemiological studies led quickly to the assessment of Premarin for the treatment of mild to moderate Alzheimer's disease (AD), initiated by the Alzheimer's Disease Cooperative Study Group and headed by Dr. Leon Thal. While this and subsequent trials with Premarin (Wyeth Research, Monmouth Junction, New Jersey) and PremPro (Wyeth Research), a conjugated equine estrogen preparation plus medoxyprogresterone acetate, have not supported the use of estrogens in treating advanced AD, considerable inferences have been made from these placebo controlled trials of estrogens. Here, we aimed to put these AD trials of estrogens in perspective by considering the potential mechanisms of these potent neuroprotective estrogens, the role of estrogens in other neurodegenerative conditions, such as cerebral ischemia, and based on our current understanding of estrogen neurobiology, offer insight into the design of future clinical trails of estrogens for neuronal protection.

Vasoactive biomarkers and oxidative stress in healthy recently postmenopausal women treated with hormone replacement therapy

BACKGROUND

Despite biologically plausible mechanisms for cardiac protection from estrogen therapy, recent clinical trials have suggested possible cardiovascular risk rather than benefit. However, it has been speculated that cardioprotective benefits from hormone replacement therapy (HRT) may be more evident in the early postmenopausal period. We have previously reported early beneficial effects on biochemical markers of endothelial function in healthy women after short-term estradiol replacement therapy. In this study we aimed to evaluate the effect of long-term HRT on different vasoactive factors and oxidative stress in healthy recently postmenopausal women.

METHODS

Fifteen women (age 50 +/- 1 years, time since menopause 1.6 +/- 0.1 years) were randomized to a sequential oral and transdermal estradiol regimen (2 mg oral micronized 17beta-estradiol/day or 1.5 mg 17beta-estradiol gel/day). Oral dydrogesterone (10 mg/day, 12 days/month) was then cyclically combined with either of the estrogen therapies for 1 year. Blood samples were collected at baseline and after 1, 2, 6 and 12 months of therapy to evaluate levels of follicle stimulating hormone (FSH), estradiol, 6-keto PGF1alpha (prostacyclin metabolite), nitrite/nitrate, epinephrine, norepinephrine, 8-isoprostane (8-epi PGF2alpha) and lipid profile values.

RESULTS

FSH levels decreased (p < 0.001) while estradiol levels increased (p < 0.001) during HRT. Levels of epinephrine (p < 0.001), norepinephrine (p < 0.01), mean blood pressure (p < 0.01) and low density lipoprotein (LDL) cholesterol (p < 0.01) decreased, and nitrite/nitrate levels increased (p < 0.01) during HRT, which did not significantly affect 8-epi PGF2alpha levels.

CONCLUSIONS

One-year HRT significantly reduced the levels of catecholamines, mean blood pressure and LDL cholesterol while it increased levels of nitrite/nitrate, indicating cardiovascular benefit in healthy recent postmenopausal women. Levels of 8-epi PGF2alpha did not change, suggesting no evident relationship between HRT and oxidative stress.

Postmenopausal hormone therapy: who now takes it and do they differ from non-users?

BACKGROUND

Considerable changes in hormone therapy use have taken place in the last few years.

AIMS

To determine current usage of postmenopausal hormone therapy and assess the trend and rate of change in hormone therapy usage over the last 13 years. Additionally, to assess differences between current users and non-users for health-related and risk factor variables.

METHODS

Questions regarding hormone therapy use have been included in an annual face to face population health survey of South Australians eight times since 1991. In 2004, additional questions on health status and quality of life were included.

RESULTS

In 2004, current use of hormone therapy was 15.4, 19.8 and 31.2% in all women over 40, 50 and 50-59 years, respectively. Ever use of hormone therapy among all women over 50 years was 46.5% with a mean duration of use of 7.46 years. Hormone therapy users did not differ from non-users in chronic disease indicators, body mass index, complementary medicine or therapist use, other health service use, socioeconomic status or quality of life. Increased hormone therapy use was associated with higher income, better educated, employed and married women in their sixth decade. Current use has varied over the years, with an increase to 2000, but a drop in 2003 and 2004.

CONCLUSION

Apart from menopausal symptoms, there is no evidence to support differences between users and non-users in terms of quality of life or health characteristics, requiring more appropriate selection of women for hormone therapy.

Estrogen therapy effects on different vasoactive factors in recent postmenopausal healthy women

BACKGROUND

To evaluate whether the route of estrogen therapy (ET) may affect the levels of different vasoactive factors in healthy recent post-menopausal women.

METHODS

We conducted a cross-over study in 20 healthy nonsmoking women in recent postmenopause (1.8+/-0.1 years). Women received either 1-month oral-ET (O-ET, 2 mg oral micronized 17beta estradiol daily) or transdermal-ET regimen (T-ET, 17beta estradiol 1.5 mg gel daily) with a 1-month wash-out interval. Blood pressure, plasma levels of endothelin-1 (ET), 6-ketoPGF1a (6-ketoPG, prostacyclin metabolite), nitrite/nitrate (NOx), epinephrine (E) and norepinephrine (NE) and lipid profile were measured at baseline and after each treatment.

RESULTS

Both regimens significantly reduced E (p<0.01) and NE levels (p<0.05). O-ET reduced low-density lipoproteins (LDL) levels (p<0.05) and increased NOx values (p<0.01). Neither regimen caused significant changes of ET or 6-ketoPG.

CONCLUSIONS

Our results, obtained in healthy women in recent menopause, indicate that the ratio between vasodilator (NOx and prostacyclin) and vasoconstrictor (ET) bioavailability shifted towards the previous ones after O-ET, while it remained unchanged after T-ET; moreover, catecholamines levels were reduced by both treatments already from 1 month of therapy. These changes might represent very early beneficial effects evoked by ET on the cardiovascular system.

Early postmenopausal hormone therapy may prevent cognitive impairment later in life

OBJECTIVE

Estrogen deficiency has been implicated as a risk factor for cognitive impairment in elderly women, yet the role of hormone therapy (HT) to prevent this event remains controversial. The aim of this study was to investigate the impact of administration of HT for 2 to 3 years in the early postmenopausal years on the risk of cognitive impairment 5 to 15 years later.

DESIGN

We followed a group of 343 women who had received HT in randomized, placebo-controlled trials and were reexamined 5, 11, or 15 years after completion of therapy. Of these women, 261 received either HT or placebo for 2 to 3 years during the trials with no further hormone treatment until follow-up, and the remaining 82 women reported either prolonged or current use of HT at reexamination. Outcome of the study was cognitive function assessed by the short Blessed test that includes tests of orientation, concentration, and memory function on a scale of 0 to 28 (score > or =6 indicates cognitive impairment).

RESULTS

The mean age of participants at follow-up was 65 +/- 3 years. There was no difference in the mean cognitive scores between ever HT users and never users. For women who received 2 to 3 years of HT, the risk of cognitive impairment (cognitive score > or =6) was decreased by 64% (odds ratio [OR]: 0.36, 95% CI: 0.15-0.90; P = 0.03). A similar OR was found in long-term/current HT users. Adjustment for age, alcohol intake, current smoking, and education did not alter the results.

CONCLUSION

The results of the present study suggest that previous short-term HT administered in the early phase of the menopause may provide a long-term protection against cognitive impairment.

Estrogens, lipoproteins, and cardiovascular risk factors: an update following the randomized placebo-controlled trials of hormone-replacement therapy

PURPOSE OF REVIEW

The effects of hormone-replacement therapy on cardiovascular risk factors are examined. In an attempt to explain the results of recent randomized controlled trials in which no benefit of hormone-replacement therapy for postmenopausal women has been observed,

RECENT FINDINGS

Changes in lipoproteins in response to hormone-replacement therapy have now been analysed for both primary and secondary prevention studies. In none of the large randomized controlled trials was there any effect of hormone-induced changes in low-density lipoprotein, high-density lipoprotein, or triglyceride on clinical outcome. Further detailed studies of lipoprotein metabolism have not revealed any adverse effect of hormone-replacement therapy. Recent analysis of the Heart Estrogen/Progestin-Replacement Study data suggests hormone-replacement therapy reduces the risk of developing diabetes. The effect of hormone-replacement therapy on inflammatory markers and on flow-mediated dilatation is largely beneficial, although the effect on flow-mediated dilatation is modulated according to endothelial function, which is adversely affected by known risk factors, including age and presence of atherosclerosis. In this respect the work on polymorphisms of estrogen receptor-alpha may in due course help to define those women who would benefit most from use of estrogen. Crucially, oral but not transdermal hormone-replacement therapy increases activated protein C resistance independently of the presence of factor V Leiden. This effect increases the risk of venous thromboembolic events, which is reflected in the results of a hospital case control study of thromboembolism.

SUMMARY

Despite the outcome of the hormone-replacement therapy trials, recent work has confirmed the putative antiatherogenic effects of hormone-replacement therapy on lipoprotein metabolism. Metabolic differences of route of administration of estrogen, particularly on haemostatic variables, may explain this clinical paradox, which continues to be an important research area.

Should Progestins Be Blamed for the Failure of Hormone Replacement Therapy to Reduce Cardiovascular Events in Randomized Controlled Trials?

Many observational studies and experimental and animal studies have demonstrated that estrogen replacement therapy (ERT) or hormone replacement therapy (HRT) (estrogen plus progestin) significantly reduces the risk of coronary heart disease. Nonetheless, recent randomized controlled trials demonstrated some trends toward an increased risk of cardiovascular events rather than a reduction of risk. Recently, both the HRT and ERT arms of the Women’s Health Initiative (WHI) study were terminated early because of an increased/no incidence of invasive breast cancer, increased incidence of stroke, and increased trend/no protective effects of cardiovascular disease. We discuss the controversial effects of HRT and ERT on cardiovascular system and provide a hypothesis that the failure of HRT and ERT in reducing the risk of cardiovascular events in postmenopausal women might be because of the stage of their atherosclerosis at the time of initiation of HRT or ERT.