Vascular effects of synthetic or natural progestagen combined with conjugated equine estrogen in healthy postmenopausal women

Gender-based research underscores sex differences in biological processes, clinical disorders and pharmacological interventions

Earlier research has presumed that the male and female biology is similar in most organs except the reproductive system, leading to major misconceptions in research interpretations and clinical implications, with serious disorders being overlooked or misdiagnosed. Careful research has now identified sex differences in the cardiovascular, renal, endocrine, gastrointestinal, immune, nervous, and musculoskeletal systems. Also, several cardiovascular, immunological, and neurological disorders have shown differences in prevalence and severity between males and females. Genetic variations in the sex chromosomes have been implicated in several disorders at young age and before puberty. The levels of the gonadal hormones estrogen, progesterone and testosterone and their receptors play a role in the sex differences between adult males and premenopausal women. Hormonal deficiencies and cell senescence have been implicated in differences between postmenopausal and premenopausal women. Specifically, cardiovascular disorders are more common in adult men vs premenopausal women, but the trend is reversed with age with the incidence being greater in postmenopausal women than age-matched men. Gender-specific disorders in females such as polycystic ovary syndrome, hypertension-in-pregnancy and gestational diabetes have attained further research recognition. Other gender-related research areas include menopausal hormone therapy, the "Estrogen Paradox" in pulmonary arterial hypertension being more predominant but less severe in young females, and how testosterone may cause deleterious effects in the kidney while having vasodilator effects in the coronary circulation. This has prompted the National Institutes of Health (NIH) initiative to consider sex as a biological variable in research. The NIH and other funding agencies have provided resources to establish state-of-the-art centers for women health and sex differences in biology and disease in several academic institutions. Scientific societies and journals have taken similar steps to organize specialized conferences and publish special issues on gender-based research. These combined efforts should promote research to enhance our understanding of the sex differences in biological systems beyond just the reproductive system, and provide better guidance and pharmacological tools for the management of various clinical disorders in a gender-specific manner.

To clot, or not to clot: The dilemma of hormone treatment options for menopause

Untreated menopause may have serious health implications, but treatments can have dangerous side effects. We evaluate menopausal symptoms as well as available treatments -the routes of administration and their effect on blood coagulation. Menopausal females may experience hot flushes, vulva- and vaginal atrophy and osteoporosis. Many treatments are available to relieve these symptoms such as Conjugated Equine Estrogen and bioidentical hormones. The routes of administration include oral and transdermal. Hormones that are administered orally undergo a hepatic first pass metabolism. The by-products have a lower efficacy and possibly enhanced side effects. Furthermore, hormone treatments influence the coagulation cascade through coagulation factors or their regulators. Increased coagulation poses a risk for venous thromboembolism. Currently a definite conclusion on whether the side effects from hormone treatments exceed the risk of untreated menopause cannot be made. However, a more individualised approach to hormone treatments may be the most feasible solution to this dilemma.

Hormone Therapy in Menopause: Concepts, Controversies, and Approach to Treatment

Hormone therapy (HT) is an effective treatment for menopausal symptoms, including vasomotor symptoms and genitourinary syndrome of menopause. Randomized trials also demonstrate positive effects on bone health, and age-stratified analyses indicate more favorable effects on coronary heart disease and all-cause mortality in younger women (close proximity to menopause) than in women more than a decade past menopause. In the absence of contraindications or other major comorbidities, recently menopausal women with moderate or severe symptoms are appropriate candidates for HT. The Women's Health Initiative (WHI) hormone therapy trials-estrogen and progestin trial and the estrogen-alone trial-clarified the benefits and risks of HT, including how the results differed by age. A key lesson from the WHI trials, which was unfortunately lost in the posttrial cacophony, was that the risk:benefit ratio and safety profile of HT differed markedly by clinical characteristics of the participants, especially age, time since menopause, and comorbidity status. In the present review of the WHI and other recent HT trials, we aim to provide readers with an improved understanding of the importance of the timing of HT initiation, type and route of administration, and of patient-specific considerations that should be weighed when prescribing HT.

Relation between Tissue Factor Pathway Inhibitor Activity and Cardiovascular Risk Factors and Diseases in a Large Population Sample

OBJECTIVE

 Tissue factor pathway inhibitor (TFPI) is a potent anticoagulant protein in the extrinsic coagulation pathway. In the present study, we aim to identify the cardiovascular determinants for total TFPI activity and its association with cardiovascular disease (CVD) and total mortality.

METHODS

 Total TFPI activity was assessed in a selection of the population-based Gutenberg Health Study (n = 5,000). Statistical analysis was performed to identify the determinants for total TFPI activity as well as the associations with CVD and mortality.

RESULTS

 Multivariable linear regression analysis identified smoking (β 0.095 [0.054-0.136]) as a positive determinant for total TFPI activity, while diabetes (β -0.072 [-0.134 to -0.009]), obesity (β -0.063 [-0.101 to -0.024]), and history of coronary artery disease (CAD) were negatively associated with total TFPI activity, independent of age, sex, and the remaining cardiovascular risk factors. After adjustment for lipoprotein levels, the association between total TFPI activity levels and obesity and CAD was lost. The analysis additionally revealed a strong positive association between total TFPI activity levels and low-density lipoprotein (β 0.221 [0.204-0.237]). The Cox regression models revealed that a higher total TFPI activity, above 97.5th percentile of the reference group, was associated with an increased mortality risk (hazard ratio = 2.58 [95% confidence interval: 1.49-4.47]), independent of age, sex, and cardiovascular risk profile.

CONCLUSION

 In the Gutenberg Health Study population-based cohort, the highest percentage of total TFPI correlated with an increased mortality risk. While elevated TFPI may reflect endothelial cell activation, the associations between total TFPI activity and obesity and CAD, points to additional mechanistic interactions.

Effects of oral conjugated equine estrogens with or without medroxyprogesterone acetate on incident hypertension in the Women's Health Initiative hormone therapy trials

OBJECTIVE

The aim of the study was to determine the effect of menopausal hormone therapy on incident hypertension in the two Women's Health Initiative hormone therapy trials and in extended postintervention follow-up.

METHODS

A total of 27,347 postmenopausal women aged 50 to 79 years were enrolled at 40 US centers. This analysis includes the subsample of 18,015 women who did not report hypertension at baseline and were not taking antihypertensive medication. Women with an intact uterus received conjugated equine estrogens (CEE; 0.625 mg/d) plus medroxyprogesterone acetate (MPA; 2.5 mg/d) (n = 5,994) or placebo (n = 5,679). Women with prior hysterectomy received CEE alone (0.625 mg/d) (n = 3,108) or placebo (n = 3,234). The intervention lasted a median of 5.6 years in the CEE plus MPA trial and 7.2 years in the CEE-alone trial with 13 years of cumulative follow-up until September 30, 2010. The primary outcome for these analyses was self-report of a new diagnosis of hypertension and/or high blood pressure requiring treatment with medication.

RESULTS

During the CEE and CEE plus MPA intervention phase, the rate of incident hypertension was 18% higher for intervention than for placebo (CEE: hazard ratio [HR], 1.18; 95% CI, 1.09-1.29; CEE plus MPA: HR, 1.18; 95% CI, 1.09-1.27). This effect dissipated postintervention in both trials (CEE: HR, 1.06; 95% CI, 0.94-1.20; CEE plus MPA: HR, 1.02; 95% CI, 0.94-1.10).

CONCLUSIONS

CEE (0.625 mg/d) administered orally, with or without MPA, is associated with an increased risk of hypertension in older postmenopausal women. Whether lower doses, different estrogen formulations, or transdermal route of administration offer lower risks warrant further study.

Short-term effects of low-dose estradiol on endothelial function and blood viscosity in nondiabetic postmenopausal overweight women: a double-blind, placebo-controlled study

OBJECTIVE

The beneficial effects of estrogen on endothelial function depend on its integrity. This study evaluates the short-term effects of low-dose transdermal estradiol on endothelial function, insulin sensitivity, and blood viscosity in nondiabetic overweight/obese women.

METHODS

Forty-four nondiabetic overweight/obese women with a history of recent menopause were randomly allocated, in a double-blind fashion, to receive transdermal estradiol (1 mg/d, n = 22) or placebo (n = 22). The following parameters were assessed: endothelial reactivity (venous occlusion plethysmography and nailfold videocapillaroscopy), plasma levels of soluble adhesion molecules, insulin sensitivity (homeostasis model assessment of insulin resistance and areas under the curve of insulin and glucose during an oral glucose tolerance test), and blood and plasma viscosity. Data were expressed as means ± SD or medians [first to third quartiles].

RESULTS

Participants were aged 51.8 ± 2.3 years with a body mass index of 31.5 ± 2.5 kg/m and time since menopause was 3 [2-5] years. At baseline, no differences between the groups were observed; however, after 3 months of treatment, the following changes were observed in the estradiol group compared with the placebo group: a decrease in the forearm vascular resistance at baseline (36.37 [24.9-51.27] vs 51.3 [40.88-70.03] mm Hg/mL per min 100 mL tissue, P < 0.01) and during the postocclusive reactive hyperemia response (15.93 [11.32-22.29] vs 22.13 [16.46-29.7] mm Hg/mL per min 100 mL tissue, P < 0.01), and an increase in red blood cell velocity at rest (0.316 [0.309-0.326] vs 0.303 [0.293-0.308] mm/s, P < 0.001) and during postocclusive reactive hyperemia response (0.374 [0.353-0.376] vs 0.341 [0.333-0.355] mm/s, P < 0.001). Furthermore, blood viscosity was lower in the estradiol group than in the placebo group (3.57 ± 0.12 vs 3.76 ± 0.22 mPa.s; P < 0.01).

CONCLUSIONS

Short-term use of low-dose transdermal estradiol in nondiabetic overweight/obese women with a history of recent menopause improved endothelial function and decreased blood viscosity compared with placebo.

Menopausal hormone treatment cardiovascular disease: another look at an unresolved conundrum

Cardiovascular disease (CVD) is the most common cause of death in women. Before the Women's Health Initiative (WHI) hormone trials, evidence favored the concept that menopausal hormone treatment (MHT) protects against CVD. WHI studies failed to demonstrate CVD benefit, with worse net outcomes for MHT versus placebo in the population studied. We review evidence regarding the relationship between MHT and CVD with consideration of mechanisms and risk factors for atherogenesis and cardiac events, results of observational case-control and cohort studies, and outcomes of randomized trials. Estrogen effects on CVD risk factors favor delay or amelioration of atherosclerotic plaque development but may increase risk of acute events when at-risk plaque is present. Long-term observational studies have shown ∼40% reductions in risk of myocardial infarction and all-cause mortality. Analyses of data from randomized control trials other than the WHI show a ∼30% cardioprotective effect in recently menopausal women. Review of the literature as well as WHI data suggests that younger and/or more recently menopausal women may have a better risk-benefit ratio than older or remotely menopausal women and that CVD protection may only occur after >5 years; WHI women averaged 63 years of age (12 years postmenopausal) and few were studied for >6 years. Thus, a beneficial effect of long-term MHT on CVD and mortality is still an open question and is likely to remain controversial for the foreseeable future.

Estrogen, vascular estrogen receptor and hormone therapy in postmenopausal vascular disease

Cardiovascular disease (CVD) is less common in premenopausal women than men of the same age or postmenopausal women, suggesting vascular benefits of estrogen. Estrogen activates estrogen receptors ERα, ERβ and GPR30 in endothelium and vascular smooth muscle (VSM), which trigger downstream signaling pathways and lead to genomic and non-genomic vascular effects such as vasodilation, decreased VSM contraction and growth and reduced vascular remodeling. However, randomized clinical trials (RCTs), such as the Women's Health Initiative (WHI) and Heart and Estrogen/progestin Replacement Study (HERS), have shown little vascular benefits and even adverse events with menopausal hormone therapy (MHT), likely due to factors related to the MHT used, ER profile, and RCT design. Some MHT forms, dose, combinations or route of administration may have inadequate vascular effects. Age-related changes in ER amount, distribution, integrity and post-ER signaling could alter the vascular response to MHT. The subject's age, preexisting CVD, and hormone environment could also reduce the effects of MHT. Further evaluation of natural and synthetic estrogens, phytoestrogens, and selective estrogen-receptor modulators (SERMs), and the design of appropriate MHT combinations, dose, route and 'timing' could improve the effectiveness of conventional MHT and provide alternative therapies in the peri-menopausal period. Targeting ER using specific ER agonists, localized MHT delivery, and activation of specific post-ER signaling pathways could counter age-related changes in ER. Examination of the hormone environment and conditions associated with hormone imbalance such as polycystic ovary syndrome may reveal the causes of abnormal hormone-receptor interactions. Consideration of these factors in new RCTs such as the Kronos Early Estrogen Prevention Study (KEEPS) could enhance the vascular benefits of estrogen in postmenopausal CVD.

The effects of different hormone treatment on endothelial function in healthy postmenopausal women

We aimed to compare the effects of different types of hormone treatment (HT) on endothelial function by means of brachial artery ultrasonographic examination in postmenopausal women. Sixty-two healthy postmenopausal women were included in this study. Subjects were assigned to one of the five groups receiving 6 months of treatment [estrogen (conjugated estrogen), estrogen (conjugated estrogen) plus progesterone (medroxyprogesterone acetate; MPA), raloxifene, tibolone or control]. Endothelial function was assessed by measurement of flow-mediated dilatation (FMD) and nitrate-dependent dilatation in the brachial artery. At the end of 6 months, FMD values were found to be significantly increased in women with HT use than the control group (p = 0.001). In subgroups, FMD increased significantly in the estrogen [12 ± 7 versus 25 ± 8, p = 0.001] and raloxifene groups [7 ± 5 versus 11 ± 3, p < 0.01] compared to tibolone and estrogen plus progesterone groups. In conclusion, endothelial function is impaired in postmenopausal women. Both estrogen and raloxifene regimens may improve endothelial functions in healthy postmenopausal women. The direct protective effects of these HT on the healthy endothelium may be more remarkable than the favorable effects on lipid profile.

Role and interactions of annexin A1 and oestrogens in the manifestation of sexual dimorphisms in cerebral and systemic inflammation

BACKGROUND AND PURPOSE

Gender differences in inflammation are well described, with females often showing more robust, oestrogen-associated responses. Here, we investigated the influence of gender, oestrogen and the anti-inflammatory protein annexin A1 (AnxA1) on lipopolysaccharide (LPS)-induced leukocyte-endothelial cell interactions in murine cerebral and mesenteric microvascular beds.

EXPERIMENTAL APPROACH

Intravital microscopy was used to visualize and quantify the effects of LPS (10 μg·per mouse i.p.) on leukocyte-endothelial interactions in male and female wild-type (WT) mice. The effects of ovariectomy ± oestrogen replacement were examined in WT and AnxA1-null (AnxA1(-/-) ) female mice.

KEY RESULTS

LPS increased leukocyte adherence in the cerebral and mesenteric beds of both male and female WT mice; females showed exacerbated responses in the brain versus males, but not the mesentery. Ovariectomy further enhanced LPS-induced adhesion in the brain but not the mesentery; its effects were reversed by oestrogen treatment. OVX AnxA1(-/-) mice also showed exaggerated adhesive responses to LPS in the brain. However, these were unresponsive to ovariectomy and, paradoxically, responded to oestrogen with a pronounced increase in basal and LPS-induced leukocyte adhesion in the cerebrovasculature.

CONCLUSIONS AND IMPLICATIONS

Our data confirm the fundamental role of AnxA1 in limiting the inflammatory response in the central and peripheral microvasculature. They also (i) show that oestrogen acts via an AnxA1-dependent mechanism to protect the cerebral, but not the mesenteric, vasculature from the damaging effects of LPS and (ii) reveal a paradoxical and potentially toxic effect of the steroid in potentiating the central response to LPS in the absence of AnxA1.

Progestogens used in postmenopausal hormone therapy: differences in their pharmacological properties, intracellular actions, and clinical effects

The safety of progestogens as a class has come under increased scrutiny after the publication of data from the Women's Health Initiative trial, particularly with respect to breast cancer and cardiovascular disease risk, despite the fact that only one progestogen, medroxyprogesterone acetate, was used in this study. Inconsistency in nomenclature has also caused confusion between synthetic progestogens, defined here by the term progestin, and natural progesterone. Although all progestogens by definition have progestational activity, they also have a divergent range of other properties that can translate to very different clinical effects. Endometrial protection is the primary reason for prescribing a progestogen concomitantly with postmenopausal estrogen therapy in women with a uterus, but several progestogens are known to have a range of other potentially beneficial effects, for example on the nervous and cardiovascular systems. Because women remain suspicious of the progestogen component of postmenopausal hormone therapy in the light of the Women's Health Initiative trial, practitioners should not ignore the potential benefits to their patients of some progestogens by considering them to be a single pharmacological class. There is a lack of understanding of the differences between progestins and progesterone and between individual progestins differing in their effects on the cardiovascular and nervous systems, the breast, and bone. This review elucidates the differences between the substantial number of individual progestogens employed in postmenopausal hormone therapy, including both progestins and progesterone. We conclude that these differences in chemical structure, metabolism, pharmacokinetics, affinity, potency, and efficacy via steroid receptors, intracellular action, and biological and clinical effects confirm the absence of a class effect of progestogens.

Risk of venous thromboembolic disease in postmenopausal women taking oral or transdermal hormone replacement therapy

OBJECTIVE

The influence of hormone replacement therapy (HRT) on hemostasis processes depends on the type of hormone, the combination of doses, the time of taking HRT, and the route of administration (oral, transdermal, implanted). The aim of the current study was to assess some parameters of coagulation, especially tissue factor pathway inhibitor (TFPI) and tissue factor (TF) in postmenopausal women using oral or transdermal HRT.

METHODS

The study was conducted on 76 healthy women, including 46 women aged 44-58 years who were taking oral (26) or transdermal (20) HRT, and 30 women aged 44-54 years who did not take HRT as the control group. Plasma concentrations of TF, TFPI, thrombin-antithrombin complex (TAT), and D-dimer were performed by enzyme-linked immunosorbent assay (ELISA). Moreover, the concentration of fibrinogen and activity of protein C were measured by chromogenic and chronometric methods.

RESULTS

We observed a significantly higher concentration of TF and a significantly lower concentration of TFPI in women taking oral and transdermal HRT in comparison with the control group. We also found a significantly lower concentration of fibrinogen in women taking oral HRT vs. the control group. Moreover, no statistically significant changes in concentrations of TAT and D-dimer, or activity of protein C were noted.

CONCLUSIONS

In this study, the occurrence of an increased TF concentration simultaneously with a decreased concentration of TFPI in women taking HRT indicates hypercoagulability. No significant modification of TAT or D-dimer occurred, and thus there may not be increased risk of thrombosis.

Depot-medroxyprogesterone acetate and endothelial function before and after acute oral, vaginal, and transdermal estradiol treatment

Young women using depot-medroxyprogesterone acetate (DMPA) contraception have low circulating estrogen and elevated synthetic progestin. Low estrogen and certain progestins have been shown to impact endothelial function even in young healthy women. The purpose of this study was to investigate how DMPA affects endothelial function and serum biomarkers of cardiovascular risk before and after acute oral, vaginal, and transdermal estradiol treatments. Seven young women participated on 3 study days during a normal 12-week DMPA cycle, during weeks 3, 6, and 9. An additional 8 young women participated on 6 separate days during a 12-week DMPA cycle, 3 times on DMPA only and 3 times when using DMPA plus acute estradiol treatments. Wall tracking of high-resolution ultrasound images of the brachial artery were used during endothelium-dependent flow-mediated dilation and nitroglycerin administration to test endothelial function. Serum samples were analyzed for cardiovascular indexes at each study visit. All of the estradiol treatments increased endothelium-dependent flow-mediated dilation compared with DMPA only (P<0.001). Endothelium-dependent flow-mediated dilation was not different among DMPA-only treatment days. Endothelium-independent vasodilation and cholesterol levels were unchanged across DMPA-only and DMPA plus estradiol cycles. These data suggest that acute estradiol treatments improve endothelium-dependent flow-mediated dilation in young hypoestrogenic women using DMPA.

Oral contraceptive use, iron stores and vascular endothelial function in healthy women

BACKGROUND

Increased iron stores are associated with greater cardiovascular risk in postmenopausal women. Oral contraceptive pill (OCP) use decreases the volume of menstrual blood loss and increases iron stores, but the link between OCP use, iron stores and cardiovascular risk in premenopausal women has not been characterized.

STUDY DESIGN

We conducted a cross-sectional study of 23 healthy OCP users to determine the association between type and duration of OCP exposure, iron stores, and vascular endothelial function [flow-mediated dilation (FMD) in the brachial artery].

RESULTS

Median duration of OCP use was 45 months. FMD in the brachial artery was significantly associated with progestin type used (estranes/gonanes vs. drospirenone) and duration of OCP use (both p<.05) but not iron stores. In multivariate analysis, progestin type was the only independent predictor of FMD.

CONCLUSIONS

Use of OCP containing drospirenone was independently associated with greater FMD in the brachial artery and, thus, a potentially more favorable cardiovascular risk profile, when compared with use of OCP containing estranes/gonanes.

Progestogens reduce thromboxane production by cultured human endothelial cells

OBJECTIVES

Progestogens have been poorly studied concerning their roles in endothelial physiology. Prostanoids are vasoactive compounds, such as thromboxane A2, a potent vasoconstrictor, and prostacyclin, a vasodilator. We examined the effects of two progestogens used clinically, progesterone and medroxyprogesterone acetate, on thromboxane A2 production by cultured human umbilical vein endothelial cells (HUVEC) and investigated the role of progesterone receptors and the enzymes involved in production of thromboxane A2 and prostacyclin.

METHODS

Cells were exposed to 1-100  nmol/l of either progesterone or medroxyprogesterone acetate, and thromboxane A2 production was measured in culture medium by enzyme immunoassay. Gene expression of prostacyclin synthase and thromboxane synthase was analyzed by quantitative real-time polymerase chain reaction. Expression of prostacyclin synthase protein was analyzed by Western blot.

RESULTS

Both progestogens decreased thromboxane A2 release after 24 h. Protein and gene expression of prostacyclin synthase were increased after exposure to both progestogens, without changes in thromboxane synthase expression. These effects induced by progestogens were mediated through progesterone receptors, since they were decreased in the presence of the progesterone receptor antagonist RU486. The cyclo-oxygenase-1 selective inhibitor reduced thromboxane release.

CONCLUSION

Progesterone and medroxyprogesterone acetate decreased HUVEC thromboxane release in a progesterone receptor-dependent manner, without changes in thromboxane synthase expression and enhanced prostacyclin synthase gene and protein expression.

Progesterone and medroxyprogesterone acetate differentially regulate alpha4 subunit expression of GABA(A) receptors in the CA1 hippocampus of female rats

The Women's Health Initiative trials - in which more extreme adverse outcomes were observed in the medroxyprogesterone acetate (MPA) + conjugated equine estrogen (CEE) arm, as compared to the CEE only arm - suggest that the addition of MPA to estrogen treatment has undesirable consequences. An important question raised by these results is whether the adverse outcomes observed in the progestin arm can be attributed to effects that are unique to MPA or are common to all progestins. In this study we explored the potential for MPA and progesterone (P4) to differentially impact neuroendocrine function by comparing their effects on mRNA expression for the alpha4 subunit of GABA(a) receptors in the CA1 hippocampus of female rats. Prior research has shown that P4, acting through its reduced metabolite allopregnanolone (AP), can mediate alpha4 subunit expression, thereby altering GABA(A) receptor gated currents. By contrast, MPA competitively inhibits the enzymes necessary for the synthesis of AP. In this study, ovariectomized females were primed with estradiol benzoate and then treated with P4, MPA, or vehicle. Subjects were sacrificed 12 h or 24 h later and in situ hybridization was used to measure alpha4 mRNA in the CA1 hippocampus. At 12 h but not 24 h, alpha4 mRNA was reduced in the P4 group as compared to the MPA group, and as compared to the vehicle group. These results suggest that MPA, while progestational in terms of its effects in the uterus, is not a simple substitute for P4 in other systems. The relative impact of these two progestins on neuroendocrine function must be carefully explored.

Associations of circulating adiponectin with estradiol and monocyte chemotactic protein-1 in postmenopausal women

OBJECTIVE

The aim of the present study was to clarify the association of serum adiponectin concentrations with serum 17beta-estradiol concentrations in pre-, peri-, and postmenopausal women. In addition, the associations of serum adiponectin with serum concentrations of proinflammatory and anti-inflammatory cytokines were examined in women during the menopausal transition.

DESIGN

A total of 197 women were enrolled in this study: 33 premenopausal women, 80 perimenopausal women, and 84 postmenopausal women. Serum adiponectin concentration was measured by an enzyme-linked immunosorbent assay. Serum concentrations of the proinflammatory cytokines interleukin (IL)-1beta, IL-6, and tumor necrosis factor alpha, anti-inflammatory cytokine IL-10, and the chemokines IL-8, macrophage inflammatory protein-1beta and monocyte chemotactic protein-1 were measured by using a multiplexed human cytokine assay.

RESULTS

Serum adiponectin concentration showed a significant negative correlation with serum estradiol concentration (r= -0.400, P=0.001) in postmenopausal women but not in pre- and perimenopausal women, and this correlation was significant after adjustment for age and body mass index. Serum adiponectin concentration also showed a significant negative correlation with serum monocyte chemotactic protein-1 concentration (r= -0.244, P=0.05) in postmenopausal women.

CONCLUSION

An increase in adiponectin level due to a decrease in estradiol results in a reduction in monocyte chemotactic protein-1 level in postmenopausal women, suggesting that adiponectin may be associated with a protective role against insulin resistance and atherosclerosis, which occur in the postmenopausal stage.

Progestins oppose the effects of estradiol on the endothelin-1 receptor type B in coronary arteries from ovariectomized hyperlipidemic rabbits

OBJECTIVE

Progestins may be associated with the adverse cardiovascular outcomes observed with estrogen plus progestogen therapy, but the mechanism is not resolved. In this study we examined the effect of 17beta-estradiol (E2) alone and in combination with two progestins on the endothelin-1 (ET-1) system in coronary arteries.

DESIGN

Watanabe heritable hyperlipidemic rabbits were treated orally with either E2 (4 mg/d), medroxyprogesterone acetate (MPA) (10 mg/d), norethisterone acetate (NETA) (2 mg/d), E2 + MPA, E2 + NETA, or placebo for 16 weeks (n=10 in each group). Coronary arteries were used for mRNA and myograph analyses.

RESULTS

E2 alone but not in combination with MPA or NETA increased ETB mRNA expression in coronary arteries. Accordingly, E2 alone but not in combination with MPA or NETA reduced the maximal contraction to ET-1, and the reduction was sustained after ETA but not after ETB blockade. E2 reduced preproendothelin-1 mRNA expression; however, this effect was not blunted by MPA or NETA. ETA and ET-converting enzyme-1 mRNA expression was unaffected by treatment.

CONCLUSIONS

The data suggest that long-term E2 treatment selectively attenuates ET-1-induced vasoconstriction, possibly by increasing ETB gene expression in rabbit coronary arteries and that this effect is abolished by the two progestins investigated. This observation may help to explain how progestins oppose the supposed beneficial effects of estrogen on the arterial wall.

Epidemiology of cytokines: the Women On the Move through Activity and Nutrition (WOMAN) Study

Using multiplex technology, the authors investigated the laboratory and biologic variation of a panel of cytokines (interleukin (IL)-1a, IL-1 receptor antagonist, IL-4, IL-6, IL-8, IL-10, interferon-inducible protein-10, monocyte chemoattractant protein-1, and tumor necrosis factor-alpha) over 18 months and their relations to cardiovascular disease risk factors, hormone therapy, and weight loss. Data were obtained from the Woman On the Move through Activity and Nutrition (WOMAN) Study, a randomized clinical trial investigating the effect of nonpharmacologic interventions on subclinical atherosclerosis among overweight, postmenopausal women in Pennsylvania. The present analysis (February 2002-August 2005) comprised 290 women aged 52-62 years (mean age = 57 years). Most of the cytokines were detectable in a majority of the samples, and the between-individual biologic variation was greater than the within-individual biologic and laboratory variation. There was little association between use of hormone therapy at baseline or change in hormone therapy by 18 months and cytokine levels. Weight loss was associated with a decrease in levels of IL-1 receptor antagonist, IL-6, and C-reactive protein. The results suggest that a wide panel of cytokines may be measured simultaneously from one sample. There is large unexplained variability in cytokine levels that is probably due to genetic-environmental associations.

Differential impact of conventional-dose and low-dose postmenopausal hormone therapy, tibolone and raloxifene on C-reactive protein and other inflammatory markers

BACKGROUND

Postmenopausal hormone therapy (HT) is associated with an increased risk for arterial and venous thrombosis.

OBJECTIVES

To compare the impact of HT, tibolone, and raloxifene on C-reactive protein (CRP) and other inflammatory markers, and to investigate possible underlying mechanisms for changes in CRP and D-dimer.

METHODS

Two hundred and two healthy women were randomly assigned to treatment for 12 weeks with either low-dose HT containing 1 mg of 17beta-estradiol and 0.5 mg of norethisterone acetate (NETA) (n = 50), conventional-dose HT containing 2 mg of 17beta-estradiol and 1 mg of NETA (n = 50), 2.5 mg of tibolone (n = 51), or 60 mg of raloxifene (n = 51).

RESULTS

CRP increased in the conventional-dose HT and low-dose HT groups. These changes were significantly more pronounced in the conventional-dose HT group (RMANOVA, P = 0.02). Also, tibolone was associated with an increase in CRP, in contrast to raloxifene, which reduced CRP. Reductions in levels of Lp(a), intercellular adhesion molecule-1 (ICAM-1), P-selectin, E-selectin, monocyte chemotactic protein 1 (MCP-1) and interleukin-6 (IL-6) were observed in all treatment groups. The changes were most pronounced for the conventional-dose HT group, and least pronounced for the raloxifene group, whereas the changes in those allocated to tibolone and low-dose HT were intermediary. Increased levels of tumor necrosis factor (TNF)-alpha and von Willebrand factor (VWF) were seen in the raloxifene group. We observed positive associations between changes in IL-6, VWF, MCP-1, and CRP.

CONCLUSIONS

The regimens had markedly different impacts on markers of inflammation. The average increase in CRP was not accompanied by increases in the average levels of IL-6, TNF-alpha or other markers, but women with large reductions in IL-6 had reduced increases in CRP.

Joint position statement of the Polish Cardiologic Society, the Polish Gynaecological Society and the Polish Menopause and Andropause Society on the effect of postmenopausal hormone replacement therapy on the cardiovascular system

The group of experts representing the Polish Cardiologic Society, the Polish Gynecological Society and the Polish Menopause and Andropause Society has issued this Joint Position Statement based on the review of available literature on the effect of postmenopausal hormone replacement therapy on the cardiovascular system. The results of older clinical and epidemiological studies are confronted with the most recently published data. The importance of type, doses and delivery route of hormones is discussed with respect to the cardiovascular safety of HRT.

Review: Endothelial dysfunction: A potential tool in gender related cardiovascular disease

The overwhelming importance of distinctive cardiovascular disease profile in women has stimulated enormous efforts to disclose its cause. In this review, we discuss vascular endothelium as a potential phenotypic marker for the genetic difference. As it is a potentially modifiable factor for cardiovascular disease, every effort should be made to detect it, either directly or indirectly, at the earliest in females who are at risk, so that the future cardiovascular events might be prevented.

Estrogen, medroxyprogesterone acetate, endothelial function, and biomarkers of cardiovascular risk in young women

Medroxyprogesterone acetate (MPA) is widely known for its use in combination hormone therapy for postmenopausal women. However, MPA is also commonly used in young women for contraception and treatment of a number of gynecological conditions. Despite its widespread use, the cardiovascular effects of MPA in young women are unclear. Therefore, the purpose of this study was to determine the acute effects of MPA when used in combination with estradiol on markers of cardiovascular risk in young women. We suppressed endogenous estrogens and progesterone in 10 premenopausal women using a gonadotropin-releasing hormone antagonist (GnRHa) for 10 days. On day 4 of GnRHa subjects received 0.1 mg of estradiol (GnRHa+E(2)), and on day 7 5 mg of MPA was added (GnRHa+E(2)+MPA). Endothelium-dependent vasodilation and endothelium-independent vasodilation of the brachial artery, lipids, homocysteine, high-sensitivity C-reactive protein, and endothelin-1 were assessed during treatment with GnRHa, GnRHa+E(2), and GnRHa+E(2)+MPA. Four additional subjects were tested to validate the efficacy of the GnRHa model and confirm the findings. Endothelium-dependent vasodilation was greater during GnRHa+E(2) than during GnRHa or GnRHa+E(2)+MPA (P = 0.006). Endothelin-1 was lower during GnRHa+E(2) than GnRHa alone (P = 0.039). Endothelin-1 increased with the addition of MPA and was not significantly different from GnRHa alone. There were no differences in the other markers of cardiovascular risk between hormone treatment days. These data suggest that acute MPA administration negates the beneficial effects of estradiol on endothelium-dependent vasodilation in young women. In addition, these data suggest that estradiol decreases endothelin-1 concentrations and the addition of MPA may counteract the effect of estradiol on endothelin-1.

Isoflavones and endothelial function

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

Effect of estrogen-progestin hormonal replacement therapy on blood coagulation and fibrinolysis in postmenopausal women

OBJECTIVE

To evaluate antithrombin III (AT), thrombin (Fragment 1+2 [F1+2] and thrombin-antithrombin [TAT]) generation markers, as well as other coagulation parameters, such as prothrombin time, partial activated thromboplastin time, thrombin time, fibrinogen, euglobulin lysis time, and platelet count, in postmenopausal women after hormonal therapy.

STUDY DESIGN

Forty-five patients who received either 0.625 mg/day unopposed oral conjugated equine estrogen (CEE), 0.625 mg/day oral CEE plus medroxyprogesterone acetate (MP), or 50 microg/day transdermal 17beta-estradiol plus MP, were included. Tests were performed before (T0) and after 3 (T3), 6 (T6) and 12 (T12) months of treatment. AT was determined by an amidolytic method, whereas F1+2 and TAT complex were measured by ELISA.

RESULTS

There was a significant reduction in the AT level of patients who received oral CEE plus MP at T3. There was no AT reduction in patients taking either oral CEE alone or transdermal 17beta-estradiol plus MP. F1+2 increased in all patients, but it reached statistical significance only in patients receiving transdermal 17beta-estradiol MP at T3.

CONCLUSIONS

The CEE associated with MP treatment may reduce AT levels, whereas unopposed CEE or transdermal 17beta-estradiol plus MP does not change AT. These changes might not be clinically relevant in the general population; however, hormonal replacement therapy may increase the risk of thrombosis in women with congenital or acquired thrombophilia.

Comparative effects of dydrogesterone and medroxyprogesterone acetate in critical areas: the brain and the vessels

Several epidemiological and observational studies have investigated the role of hormone replacement therapy (HRT) in postmenopausal women. Within a few years, clinicians shifted from considering HRT as the panacea for everything to considering it a venomous poison with which women, in search of the fountain of eternal youth, could instead harm themselves. This debate is not yet settled and the unexplained discrepancy between basic science and some of the clinical trials has fueled the discussion. One of the hottest areas of discussion remains the role of progestins. For many years, progestins were considered only as necessary additions to estrogen to protect the endometrium. However, we now know that every progestin has its own specific activities on different tissues, which can vary significantly between progestins of different classes and even within the same class. Indeed, different progestins may support or oppose the effects of estrogen depending on the tissue, thereby supporting the concept that the clinical selection of progestins for HRT is critical in determining potential positive or detrimental effects. Newer progestins, such as dydrogesterone, show effects that are remarkably different from those of other agents; these actions might be particularly relevant in the central nervous system and the cardiovascular system. The aim of the present paper is to review the comparative effects of dydrogesterone and other progestins at these sites, supporting the idea that the progestin has to be clinically selected.

Vascular and metabolic effects of sex steroids: new insights into clinical trials

The early discontinuation of the Women's Health Initiative trials of daily conjugated estrogens and medroxyprogesterone and of conjugated estrogens only was hailed as the "death to the use of hormone replacement regimens" in menopause. The analyses showed risks outweighing benefits of hormone therapy when given broadly to postmenopausal women. The expanding basic science and clinical research on the specific actions of sex steroids at the genomic and nongenomic level, however, shed new insight into these results. This review focuses on the vascular and metabolic effects of sex steroids to illustrate new advances. Understanding the mechanisms of sex steroid receptor action in a tissue-specific manner, ligand-specific dose responses, and the effects of steroid hormones in normal compared to diseased tissues may explain some of the outcomes in the clinical trials. Further research will clarify the potential benefits and risks of hormone therapy after menopause, both in individual patients and in selected populations.

The complex role of estrogens in inflammation

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

Different effects of oral conjugated estrogen and transdermal estradiol on arterial stiffness and vascular inflammatory markers in postmenopausal women

AIMS

We compared the effects of oral conjugated equine estrogen (CEE) therapy and transdermal estradiol therapy on pulse wave velocity (PWV) and circulating levels of vascular inflammatory markers in postmenopausal women and we also explored the interrelationship between the change in PWV and the changes in vascular inflammatory markers.

METHODS AND RESULTS

In a randomized 12-month trial, 28 postmenopausal women received a continuous oral CEE plus cyclic medroxyprogesterone acetate (MPA), 28 received a continuous transdermal estradiol patch plus cyclic MPA, and 27 did not receive either therapy. In each subject, we measured the brachial-ankle PWV (baPWV) using an automated device, the blood pressure, and the circulating levels of vascular inflammatory markers (C-reactive protein [CRP], cell adhesion molecules [CAMs], monocyte chemoattractant protein-1 [MCP-1], and matrix metalloproteinase [MMP-9]) before and 12 months after the start of the study. Oral CEE therapy did not change the baPWV but significantly increased the CRP and MMP-9 levels (P<0.05, each) and significantly decreased the CAMs and MCP-1 levels (P<0.05, each). Transdermal estradiol therapy significantly decreased the baPWV, and the CAMs and MCP-1 levels (P<0.05, each) but had no effect on the CRP or MMP-9 levels. No significant changes were seen in the control group. The blood pressures of the subjects remained unchanged. In the transdermal estradiol group, the change in baPWV was not significantly correlated with the changes in vascular inflammatory markers.

CONCLUSION

Transdermal estradiol, but not oral CEE therapy, may have antiatherosclerotic effects by improving arterial stiffness. The reduction in baPWV may contribute to the direct effect of estrogen, but not to the decrease in estrogen-induced vascular inflammatory markers.

Hormone therapy and cardiovascular risk markers and disease: focus on progestagens

Biological studies have demonstrated estrogen's beneficial effect on cardiovascular risk factors, including plasma lipoproteins, atherogenesis, vascular reactivity, inflammation and antioxidative activity. Additionally, observational studies have supported a cardioprotective effect of hormone therapy (HT), although an underlying healthy-user effect may account for these observations. Progestagens are added to protect against an increased risk of endometrial cancer observed with unopposed estrogen treatment. The inclusion of progestagen in HT has been associated with possible adverse cardiovascular outcomes. Recent, large-scale, randomized clinical studies did not confirm a beneficial cardiovascular effect of HT. On the contrary, an increased risk was found with continuous combined estrogen-progestagen regimens. The progestagen used in these trials was medroxyprogesterone acetate and other progestagen components have only been sparsely elucidated. The purpose of the present review is to outline some of the modifying effects of different progestagens on the actions of estrogen on cardiovascular risk markers and clinical end points observed in biological, observational and clinical studies.

Novel aspects of endothelium-dependent regulation of vascular tone

The vascular endothelium plays a crucial role in the regulation of vascular homeostasis and in preventing the initiation and progress of cardiovascular disease by controlling mechanical functions of the underlying vascular smooth muscle. Three vasodilators: nitric oxide (NO), prostacyclin, and endothelium-derived hyperpolarizing factor, produced by the endothelium, underlie this activity. These substances act in a co-ordinated interactive manner to maintain normal endothelial function and operate as support mechanisms when one pathway malfunctions. In this review, we discuss recent advances in our understanding of how gender influences the interaction of these factors resulting in the vascular protective effects seen in pre-menopausal women. We also discuss how endothelial NO synthase (NOS) can act in both a pro- and anti-inflammatory action and therefore is likely to be pivotal in the initiation and time course of an inflammatory response, particularly with respect to inflammatory cardiovascular disorders. Finally, we review recent evidence demonstrating that it is not solely NOS-derived NO that mediates many of the beneficial effects of the endothelium, in particular, nitrite acts as a store of NO released during pathological episodes associated with NOS inactivity (ischemia/hypoxia). Each of these more recent findings has emphasized new pathways involved in endothelial biology, and following further research and understanding of the significance and mechanisms of these systems, it is likely that new and improved treatments for cardiovascular disease will result.

Medroxyprogesterone acetate attenuates long-term effects of 17beta-estradiol in coronary arteries from hyperlipidemic rabbits

OBJECTIVE

The progestin component in hormone replacement treatment may oppose the effects of estrogen on vascular function. This study examined the effect of long-term treatment with 17beta-estradiol (E(2)) alone and in combination with two progestins on K(+) and Ca(2+)-mediated mechanisms in coronary arteries.

METHODS

Watanabe heritable hyperlipidemic rabbits were treated orally with either E(2) (4 mg/day), medroxyprogesterone acetate (MPA) (10 mg/day), norethindrone acetate (NETA) (2 mg/day), E(2)+MPA, E(2)+NETA, or placebo for 16 weeks (n=10 in each group). Coronary arteries were used for mRNA and myograph studies.

RESULTS

E(2) increased vasodilatation induced by sodium nitroprusside and decreased vasocontraction induced by potassium. The first but not the latter response was opposed by MPA. The combination of MPA and E(2), but neither compound alone enhanced nimodipine-induced vasodilatation and increased the expression of L-type voltage-gated Ca(2+) channel mRNA. NETA had no opposing effects. Hormone treatment did not affect large-conductance Ca(2+) activated or ATP-sensitive K(+) channels or cGMP-dependent protein kinase mRNA expression. Hyperlipidemia had no effect on vascular reactivity.

CONCLUSION

When E(2) is administered with MPA, effects of E(2) on nitric oxide and Ca(2+)-mediated vascular reactivity in rabbit coronary arteries are modulated. The results suggest that the progestin component in hormone replacement treatment may interfere with the supposed beneficial vascular effects of estrogen.

Circulating chemoattractants RANTES, negatively related to endogenous androgens, and MCP-1 are differentially suppressed by hormone therapy and raloxifene

BACKGROUND

The cardinal role of chronic inflammation in the development of atherosclerosis is increasingly being recognized. Estrogens may prevent the evolution of atherosclerosis by suppressing immune response. Furthermore, the conflicting reports on the cardiovascular effects of hormone therapy between observational and clinical trials have triggered interest on the effect of alternative therapies on the cardiovascular system.

OBJECTIVE

The aim of this study was to assess the effect of estrogen, estrogen-progestin, tibolone and raloxifene therapy on circulating markers of chemotaxis in healthy postmenopausal women.

METHODS

Eighty-eight postmenopausal women aged 44-62 years were randomly allocated to daily: (1) conjugated equine estrogens 0.625 mg (CEE), (2) 17beta-estradiol 1mg plus norethisterone acetate 0.5mg (E(2)/NETA), (3) tibolone 2.5mg, (4) raloxifene HCl 60 mg or (5) no treatment. Serum monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation, normal T-cell expressed and secreted (RANTES) were measured at baseline and at 3 months.

RESULTS

Endogenous testosterone and free androgen index (FAI) correlated negatively, while SHBG correlated positively with serum RANTES (testosterone: r=-0.27, p=0.033; FAI: r=-0.43, p=0.004: SHBG: r=0.34, p=0.026). Serum MCP-1 decreased significantly in the CEE group (baseline 125.3+/-51 pg/ml, 3 months 84.5+/-36.1 pg/ml, p=0.043), while no difference was detected between baseline and post-treatment levels in the other groups. Furthermore, a significant decrease in serum RANTES was observed at the end of 3 months only in the E2/NETA and the raloxifene group (E2/NETA baseline 8690.6+/-3880.0 pg/ml, 3 months 6894.0+/-1720.0 pg/ml, p=0.007; raloxifene baseline 9042.4+/-3765.6 pg/ml, 3 months 6718.1+/-2366.2 pg/ml, p=0.011).

CONCLUSION

Endogenous androgens may suppress chemotactic response. Postmenopausal hormone therapy and raloxifene may inhibit the expression of chemoattractant molecules and thus attenuate inflammation. The relevance of these findings in terms of clinically established caridoprotection remains to be clarified.

Premature ovarian failure, endothelial dysfunction and estrogen-progestogen replacement

Cardiovascular disease, including coronary artery disease, stroke and peripheral vascular disease, is the leading cause of death among women. Vascular endothelial dysfunction is an early marker of atherosclerosis. Women with premature ovarian failure (or premature menopause) present an increased risk for cardiovascular disease, which might be attributed to the early onset of vascular endothelial dysfunction, associated with sex steroid deficiency. Cyclical estrogen and progestogen therapy has been shown to restore endothelial function in these young women. Further research is required to assess primarily the long-term effects of hormone replacement therapy on cardiovascular and overall prognosis in young women with premature ovarian failure, as well as the effects of different doses, duration and routes of hormone administration in these women.

Biochemical markers surrogating on vascular effects of sex steroid hormones

The main mechanism of possible cardioprotection by estrogens appears to be a direct effect on the vasculature, resulting in an improvement of endothelial function and inhibition of atherogenesis. Numerous observational and experimental studies have demonstrated a positive correlation between estrogens and various biochemical markers surrogating direct vascular effects. In general, most markers are influenced in a similar way by oral and transdermal hormone therapy, although oral therapy may have a faster and more pronounced effect. The main difference between oral and transdermal administration may be confined to markers that are mainly or exclusively produced in the liver. Clinical studies demonstrate that progestogen addition can have an impact on the beneficial estrogen-induced changes of biochemical markers. Concerning the effects of tibolone, inconsistent data have been found. Overall, tibolone-induced beneficial changes on the various biochemical markers appear to be less marked compared with those of hormone therapy. The few data available on the direct effects of androgens on the vascular wall indicate a less favorable action of androgens on biochemical markers than of estrogens. The practical relevance of marker measurements is currently under discussion. Although evidence strongly supports some of these markers as predictors of acute events, it remains to be established whether modifying circulating levels of these markers will influence outcomes.

The effects of simvastatin, losartan, and combined therapy on soluble CD40 ligand in hypercholesterolemic, hypertensive patients

The proinflammatory mediator CD40 ligand plays an important role in atherogenesis. Biological mechanisms underlying statin and angiotensin II type 1 receptor blocker therapies differ. Therefore, we compared the effects of these therapies either alone or in combination on plasma soluble CD40 ligand (sCD40L). This was a randomized, double-blind, placebo-controlled cross-over trial with three treatment arms (each 2 months) and two washout periods (each 2 months). Forty-seven hypertensive, hypercholesterolemic patients were given simvastatin 20mg and placebo, simvastatin 20mg and losartan 100mg, or losartan 100mg and placebo daily during each 2 month treatment period. Simvastatin alone did not significantly reduce sCD40L levels relative to baseline measurements when the entire cohort was analyzed. However, simvastatin significantly reduced sCD40L levels from 5.10+/-0.34 to 3.07+/-0.43ng/ml (P=0.002) in a subgroup of 18 patients with high baseline sCD40L levels >2.95ng/ml. Combined therapy or losartan alone significantly decreased plasma sCD40L levels relative to baseline measurements by 14+/-7% (P=0.001) and 13+/-10% (P=0.001), respectively. These decreases were significantly greater than those observed with simvastatin alone (P=0.023 by ANOVA). Significant inverse correlations between baseline sCD40L levels and percent changes in sCD40L levels were observed (r=-0.456, P=0.001 after simvastatin alone; r=-0.476, P<0.001 after combined therapy; r=-0.451, P=0.002 after losartan alone). Losartan alone or combined therapy significantly reduced plasma sCD40L levels more than simvastatin alone in our subjects. Simvastatin, losartan and combined therapy significantly reduced sCD40L to the greatest extent in patients with high baseline sCD40L levels.

Effects of Transdermal Estrogen Replacement Therapy on Cardiovascular Risk Factors

The prevalence of hypertension and cardiovascular disease increases dramatically after menopause in women, implicating estrogen as having a protective role in the cardiovascular system. However, recent large clinical trials have failed to show cardiovascular benefit, and have even demonstrated possible harmful effects, of opposed and unopposed estrogen in postmenopausal women. While these findings have led to a revision of guidelines such that they discourage the use of estrogen for primary or secondary prevention of heart disease in postmenopausal women, many investigators have attributed the negative results in clinical trials to several flaws in study design, including the older age of study participants and the initiation of estrogen late after menopause.Because almost all clinical trials use oral estrogen as the primary form of hormone supplementation, another question that has arisen is the importance of the route of estrogen administration with regards to the cardiovascular outcomes. During oral estrogen administration, the concentration of estradiol in the liver sinusoids is four to five times higher than that in the systemic circulation. This supraphysiologic concentration of estrogen in the liver can modulate the expression of many hepatic-derived proteins, which are not observed in premenopausal women. In contrast, transdermal estrogen delivers the hormone directly into the systemic circulation and, thus, avoids the first-pass hepatic effect.Although oral estrogen exerts a more favorable influence than transdermal estrogen on traditional cardiovascular risk factors such as high- and low-density lipoprotein-cholesterol levels, recent studies have indicated that oral estrogen adversely influences many emerging risk factors in ways that are not seen with transdermal estrogen. Oral estrogen significantly increases levels of acute-phase proteins such as C-reactive protein and serum amyloid A; procoagulant factors such as prothrombin fragments 1+2; and several key enzymes involved in plaque disruption, while transdermal estrogen does not have these adverse effects.Whether the advantages of transdermal estrogen with regards to these risk factors will translate into improved clinical outcomes remains to be determined. Two ongoing clinical trials, KEEPS (Kronos Early Estrogen Prevention Study) and ELITE (Early versus Late Intervention Trial with Estradiol) are likely to provide invaluable information regarding the role of oral versus transdermal estrogen in younger postmenopausal women.

Gender-based differences in brachial artery flow-mediated vasodilation as an indicator of significant coronary artery disease

Ultrasound of the brachial artery is widely used to assess endothelial function, but whether brachial artery flow-mediated vasodilation (FMD) differs between women and men who have coronary artery disease (CAD) has not been examined. To investigate gender-based differences in brachial artery FMD as an indicator of significant CAD, FMD was measured in women and men outpatients who had CAD (coronary stenosis >50%, n = 64) and those who did not have significant CAD (n = 145). FMD in women who had CAD (n = 33, 9.1 +/- 0.8%) was higher than that in similarly aged men who had CAD (n = 31, 6.4 +/- 0.5%; p = 0.008). The FMD cutpoint that maximized sensitivity with least effect on specificity for screening CAD was 15% (91% sensitivity, 25% specificity) in women but 10% (90% sensitivity, 43% specificity) in men. If the cutpoint as defined in men were used to evaluate women, brachial artery ultrasound would fail to diagnose 42% of women who do not have significant CAD; thus, a higher FMD cutpoint is required to optimize the sensitivity of FMD for identifying women who have significant CAD compared with similarly aged men. In studies using FMD to evaluate cardiovascular risk, different standards should be applied for women and men.