Long-term effects of combined hormone replacement therapy on markers of endothelial function and inflammatory activity in healthy postmenopausal women

Estrogen regulation of endothelial and smooth muscle cell migration and proliferation: role of p38 and p42/44 mitogen-activated protein kinase

OBJECTIVE

Restenosis is a major limitation of percutaneous coronary intervention. Migration and proliferation of vascular cells remain a cornerstone in neointimal formation. The cardioprotection of estrogen is well recognized, but the intracellular mechanisms related to these beneficial effects are not completely understood.

METHODS AND RESULTS

We investigated the effects of 17beta-estradiol (17betaE) on mitogen-activated protein kinase (MAPK) activity and the migration and proliferation of porcine aortic endothelial cells (PAECs) and porcine smooth muscle cells (PSMCs). Treatment with 17betaE (10(-8) mol/L) abrogated p38 and p42/44 MAPK phosphorylation mediated by platelet-derived growth factor-BB as well as the migration and proliferation of PSMCs. In contrast, treatment with 17betaE (10(-8) mol/L) induced the phosphorylation of p38 and p42/44 MAPK and the migration and proliferation of PAECs. Interestingly, the effects of 17betaE on PSMCs and PAECs were reversed by selective estrogen receptor antagonists (tamoxifen, 4-OH-tamoxifen, and raloxifen). These results suggest that in PSMCs, 17betaE inhibits chemotactic and mitogenic effects of platelet-derived growth factor-BB as well as p38 and p42/44 MAPK phosphorylation. In contrast, 17betaE promotes in PAECs the phosphorylation of p42/44 and p38 MAPK as well as the migration and proliferation of these cells.

CONCLUSIONS

Treatment with 17betaE has a dual beneficial effect: the improvement of vascular healing and the prevention of restenosis after angioplasty.

Effects of low dose hormone replacement therapy on markers of inflammation in postmenopausal women

OBJECTIVE

Concentrations of soluble fractions of cell adhaesion molecules [sCAM], C-reactive protein (CRP) and serum amyloid A (SAA) are predictive for future cardiovascular events in postmenopausal women. The effect of hormone replacement therapy (HRT) on these inflammatory markers is not uniform. In the presented study the effect of a low-dose HRT preparation, on sCAM, CRP and SAA in healthy postmenopausal women was evaluated.

METHODS

Serum levels of intracellular adhesion molecules (sICAM-1), vascular cell adhesion molecules (sVCAM-1), P-selectin, CRP and SAA were measured at baseline and after 12 weeks of treatment with continuous combined HRT containing 1 mg micronized 17beta-estradiol and 0.5 mg norethisterone acetate. The concentrations of total cholesterol, triglycerides LDL-cholesterol and HDL-c were measured as well.

RESULTS

The studied low dose continuous combined therapy significantly reduced the concentration of sICAM-1, sVCAM-1 and P-selectin by 25.3, 20 and 34%, respectively. Despite statistically not significant the concentration of CRP and SAA increased by 35.6 and 9.4%, respectively. A statistically significant decrease in the triglycerides and TC/HDL-cholesterol ratio has been found.

CONCLUSIONS

The outcomes of the presented study suggest that HRT with low dose continuous combined HRT containing 1 mg micronized 17beta-estradiol and 0.5 mg norethisterone acetate have divergent effects on studied parameters of vascular inflammation. These effects are similar to effects of other studied HRT combinations. To our best knowledge this is the first study evaluating the effect of HRT on the concentration of SAA.

Regulation of the vasculature: clues from lupus

Blood vessel homeostasis involves a complex interplay between inflammatory signals, hormones, and other mediators. Recent research suggests that although atherosclerosis is primarily a problem of impaired lipid regulation, the very processes of cholesterol and triglyceride metabolism are intrinsically tied to inflammatory and hormonal regulatory signals. Similarities between inflammatory and endocrine disturbances in systemic lupus and the predicted consequences for vascular regulation help explain the high incidence of premature atherosclerosis in lupus. Atherosclerosis in systemic lupus, then, may be a consequence of imbalances in what are intrinsic homeostatic mechanisms, rather than a result of externally superimposed pathologic changes.

Effects of hormone replacement therapy on blood platelets

BACKGROUND

Hormone replacement therapy (HRT) increases the risk of cardiovascular morbidity in postmenopausal women under certain circumstances. Part of this effect may be the result of the influence of HRT on blood platelets. We studied the effect of short-term oral hormone replacement therapy (unopposed oestradiol or sequentially combined oestradiol and trimegestone or dydrogesterone) on platelet activation parameters in healthy postmenopausal women.

DESIGN

We designed a prospective, randomised, placebo-controlled 12-week study. Sixty healthy, normotensive, nonhysterectomised, postmenopausal women received daily micronised oestradiol (E2) 2 mg (n = 16), or 2 mg E2 daily sequentially combined with either trimegestone 0.5 mg daily (n = 14) or dydrogesterone 10 mg daily (n = 14), or placebo (n = 16). Data on platelet activation were collected at baseline and after 12 weeks of treatment using flow cytometry.

RESULTS

Twelve weeks of treatment with combined HRT was associated with an increase in platelet activation parameters P-selectin and glycoprotein 53 (by 17% and 14%, respectively, P = 0.04 vs. the placebo group for both comparisons), suggesting alpha granule and lysosome degranulation. E2 replacement therapy was associated with an increase in P-selectin labelling by 22% (P = 0.04 vs. the placebo group).

CONCLUSION

Short-term treatment with oestradiol or combined HRT increases the amount of circulating activated platelets as measured by flow cytometry. This could be a mechanism by which short-term HRT might increase the risk of thrombosis.

17 beta-Estradiol induces a rapid, endothelium-dependent, sex-specific vasodilatation in spontaneous constricted rat arterioles

OBJECTIVE

Our purpose was to resolve the apparent contradiction between the endothelium-dependent and endothelium-independent vasodilator effects of 17 beta-estradiol reported in different studies.

STUDY DESIGN

The inner diameters of isolated pressurized spontaneously constricted muscle arterioles (diameter = 63 microm) from Wistar rats (n = 21) were measured during exposure to 17 beta-estradiol, and the role of the endothelium and the influence of sex were assessed.

RESULTS

A dose-dependent dilatation was observed during exposure to 17 beta-estradiol concentrations from 10(-10) to 10(-4) mol/L. Arterioles of female rats displayed significantly more dilatation than vessels from male rats. The dilatation was significantly less in endothelium-denuded arterioles or after pretreatment with and in the presence of a nitric oxide synthase inhibitor.

CONCLUSIONS

These results provide strong evidence that, in addition to an endothelium-independent effect, 17 beta-estradiol has a dose-dependent, endothelium-mediated, rapid vasodilatory effect on muscle arterioles from the rat, which is stronger in female rats than in male rats.

Effects of transdermal hormone replacement therapy on levels of soluble P- and E-selectin in postmenopausal healthy women

OBJECTIVE

To study the adhesion molecule pattern in postmenopausal women who were not receiving hormone replacement therapy (HRT), HRT users, and fertile women.

DESIGN

Case-control study.

SETTING

Second University of Naples, Naples, Italy.

PATIENT(S)

Fifty healthy naturally postmenopausal women and 20 fertile women.

INTERVENTION(S)

Twenty-six women received no HRT and 24 received continuous transdermal 17 beta-estradiol, 0.05 mg/d, plus oral acetate nomegestrol, 5 mg/d.

MAIN OUTCOME MEASURE(S)

Levels of the soluble forms of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and P-selectin.

RESULT(S)

Women who did not received HRT showed a trend toward higher levels of soluble E-selectin and had significantly higher levels of soluble P-selectin than did fertile women. Levels of soluble E-selectin and soluble P-selectin were significantly lower in HRT users than in nonusers. Levels of VCAM-1 levels were significantly higher in HRT users than in fertile women, but no significant differences in CAM concentrations were found between the other groups.

CONCLUSION(S)

Menopause may lead to increased levels of soluble E- and soluble P-selectin, whereas long-term HRT is associated with lower selectin concentrations. This suggests that HRT may have a beneficial effect on endothelial function.

Association of postmenopausal hormone replacement therapy with carotid atherosclerosis and soluble thrombomodulin: the vascular aging (EVA) study. Etude du Vieillissement Artériel

Hormone replacement therapy (HRT) may reduce atherosclerosis among postmenopausal women, partly by reducing vascular endothelium damage. We have tested this hypothesis by evaluating the association of HRT with firstly, carotid intima media thickness (IMT) and plaques, and secondly, with endothelial cell damage, indicated by soluble thrombomodulin (sTM). Then, we tested the association between the two markers of atherosclerosis and the levels of sTM. Among 747 postmenopausal women included into the EVA study, we compared 154 HRT users (including 80% transdermal treatment) with 593 never users. Carotid IMT and plaques were measured with B-mode ultrasonography and sTM with ELISA. At least one plaque was detected among 13.6% of HRT users and 27.3% of never users. After adjustment for confounding factors, the odds ratio for the presence of plaque was 0.45 (95% confidence interval, 0.25-0.78, P=0.005) in HRT users in comparison with nonusers. HRT users had a slightly lower crude mean IMT than nonusers, but the difference was not significant. sTM was positively associated with mean IMT (P for trend=0.001) but not with plaques. Finally, estrogen users had a lower sTM level than nonusers (difference 0.14 ng/ml, P=0.03). As HRT was associated with sTM and plaques, but not with IMT, while sTM was only associated with IMT, our hypothesis was not confirmed. This suggests that the possible beneficial effects of HRT on atherosclerosis may not go through the endothelial cell damage assessed by plasma thrombomodulin.

Hormone replacement therapy at the threshold of 21st century

The management of postmenopausal women has become a major focus for the medical profession. The menopause era should progress from a period of "chaos" to an orderly understanding of the many issues related to the menopause and hormone replacement therapy (HRT). Although HRT has beneficial clinical effect and positive benefit/risk ratio, understanding of the side effects and weight gain, and, especially, a fear of cancer limit compliance. New data from long-term, controlled, prospective studies on the effects of different HRT schedules on cancer, cardiovascular disease and osteoporotic fracture risk are needed. HRT should be considered either as for prevention or for individualized care since women experience menopause as individuals, care should be taken not to make inappropriate generalizations. The priority should be the administration of appropriate medication to women with the best result in order to improve health care and quality of life. New therapeutic options will offer substantial medical advancement for the treatment of postmenopausal women.

Glycaemic control and plasma lipoproteins in menopausal women with Type 2 diabetes treated with oral and transdermal combined hormone replacement therapy

AIMS

To compare the effect of a fixed combination of an oestrogen (17-beta oestradiol) with a cyclical progestagen (norethisterone) on glycaemic control, plasma lipoproteins and haemostatic factors in women with Type 2 diabetes.

METHODS

Oral and transdermal hormone replacement therapy (HRT) were compared to no HRT treatment in 33 postmenopausal women with Type 2 diabetes, in a 12-week randomised prospective open parallel group study.

RESULTS

In the 11 women who received 12 weeks of oral HRT, there was a significant fall in total cholesterol (5.9+/-1.0 (S.D.) to 4.7+/-1.0 mmol l(-1), P=0.005), low density lipoprotein cholesterol (3.44+/-0.89 to 2.77+/-0.92 mmol l(-1), P=0.005) and triglyceride values (median (range)), (2.46 (0.96-5.52) to 2.29 (1.00-3.87) mmol l(-1), P<0.05). Oral HRT improved glycated haemoglobin (HbA(1c)) (7.4+/-1.4 to 6.8+/-1.2%, P< or =0.005). Oral HRT additionally reduced the cell adhesion factor E-selectin (82+/-33 to 60+/-20 microg l(-1), P<0.01) and factor VII (143+/-25 to 109+/-24% pooled plasma activity, P<0.01). No improvement in any of these parameters, except E-selectin (65+/-19 to 58+/-18 microg l(-1), P<0.01), occurred in the nine women receiving transdermal HRT, and no improvement occurred in the 13 controls randomised to no treatment.

CONCLUSION

In women with Type 2 diabetes, cyclical oestrogen and progestagen taken orally for 12 weeks significantly improved glycaemic control and lipoprotein concentrations. These metabolic benefits were not apparent when a similar HRT preparation was administered transdermally.

Hormone replacement therapy and endothelial function. Results of a randomized controlled trial in healthy postmenopausal women

OBJECTIVE

To compare the effects of 3 months treatment with tibolone (a single entity synthetic steroid hormone with estrogenic, progestanic and androgenic activities), or continuous combined conjugated equine estrogens (CEE) plus medroxyprogesterone acetate (MPA), with placebo, on endothelial function.

DESIGN

A single center, randomized, double-blind, placebo-controlled study.

SETTING

Research center as part of the University Medical Center Utrecht.

SUBJECTS

One hundred and five healthy postmenopausal women, sampled from the general population.

INTERVENTIONS

Three months treatment with tibolone or CEE+MPA or placebo.

MAIN OUTCOME MEASURE

At baseline and after 3 months, endothelial function was assessed non-invasively by measuring percent lumen diameter change in the brachial artery after reactive hyperemia and sublingual nitroglycerine spray.

RESULTS

Results are presented as mean differences between treatment groups of endothelium dependent flow mediated dilatation (fmd) and endothelium independent nitroglycerine induced dilatation with 95% confidence intervals (95% CI). After treatment, there was a significant difference in mean fmd between the CEE+MPA group and the placebo group of 2.5% (95% CI: 0.3-4.6) while the tibolone group and the placebo group did not differ significantly (0.6%; 95% CI: 1.6-2.8). Nitroglycerine induced dilatation did not differ significantly between the groups.

CONCLUSIONS

Hormone replacement therapy with CEE+MPA for 3 months increases endothelium dependent fmd of the brachial artery in healthy postmenopausal women. Tibolone did not alter fmd. The clinical significance of this improvement in fmd for cardiovascular disease risk needs to be established.

The mechanisms of thrombotic risk induced by hormone replacement therapy

OBJECTIVES

To review the available information on the action of hormones on the mechanisms involved in thrombotic risk.

RESULTS AND CONCLUSIONS

Thrombosis plays a crucial role in the genesis and progression of both coronary heart disease (CHD) and venous thromboembolic disease (VTED), the two main forms of cardiovascular disease. Two main determinants of the thromboembolic phenotype, hypercoagulable state and altered endothelium, accumulate much of the work performed on the influence of hormones on thrombosis. Information has accumulated mainly for oestrogens, but increasing evidences support a role for progestogens. The sensitivity of each of the three components of the hemostatic balance, the coagulation cascade, the anticoagulant system and fibrinolysis, to oestrogens has been widely examined in the literature. Functional tests suggest that HRT is accompanied by a procoagulant state. Much of the work has concentrated on changes induced on reputable indicators of risk for either CHD or VTED. Distinct indicators of increased coagulability, such as resistance to activated C protein, antithrombin or tissue factor pathway inhibitor have been selected for VTED, whereas factor VII, fibrinogen, and defective fibrinolysis, for CHD. Different states of genetic susceptibility have been involved in both forms of the disease. The status of health of endothelium, defines another scenario for attention in CHD. A long-term anti-atherogenic action of oestrogens, which may be associated with short-term risk in cases of atherosclerosis-induced endothelial dysfunction, may most adequately explain much of the clinical observation. In both CHD and VTED, the procoagulant changes initiate soon after HRT administration.

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.

Duration of menopause and behavior of malondialdehyde, lipids, lipoproteins and carotid wall artery intima-media thickness

AIM

our study assessed whether minor or major hormonal deficiency influenced oxidative status and vascular wall structure in menopausal women.

METHODS

the study series was made up of 62 non hypertensive non diabetic menopausal women (mean age 52.3+/-4.7 years) divided into two groups depending on duration of menopause (group 1 duration 0-5 years; group 2 duration over 5 years). Total cholesterol (TC), LDL cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglycerides (TG), malondialdehyde (MDA) and common carotid artery wall intima-media thickness (IMT) were determined in the entire series.

RESULTS

mean TC, LDL-C, TG, MDA and IMT values were higher in group 2 than group 1. The intergroup difference between MDA (P<0.007) and IMT values (P<0.006) values was statistically significant.

CONCLUSIONS

the study revealed a close temporal correlation between plasma oxidative stress and carotid wall IMT, jeopardizes vascular wall status as menopause proceeds.

Assessing the role of oestrogen in the prevention of cardiovascular disease

Coronary heart disease remains the leading cause of death in postmenopausal women around the world, and interest is high in discovering the best treatments and methods of prevention for this disease. For many years, it appeared that one such treatment could be oestrogen, because of its beneficial effects on the vascular endothelium and on cholesterol concentrations. However, recent clinical trials have shown no beneficial effect of long-term hormone replacement therapy (HRT) on risk for major cardiovascular events among women with established coronary disease. These surprising findings have led to still further analyses to elucidate plausible explanations. This paper will review the results from recent trials and clinical studies of HRT, as well as ongoing trials that continue to examine the role of oestrogen in the treatment and prevention of cardiovascular disease.

The phytoestrogen alpha-zearalenol reverses endothelial dysfunction induced by oophorectomy in rats

It has been shown recently that alpha-zearalenol, a resorcyclic acid lactone, prevents bone loss in a rat model of postmenopausal bone loss. We have therefore investigated the effects of this phytoestrogen on endothelial dysfunction induced by estrogen deficiency in rats. Female mature Sprague-Dawley rats underwent a bilateral oophorectomy (OVX rats). Sham-operated animals (sham OVX rats) were used as controls. Three weeks after surgery, animals were randomized to the following treatments: alpha-zearalenol (1 mg/kg/day, i.m., for 4 weeks), 17beta-estradiol (20 microg/kg/day, i.m., for 4 weeks), or their vehicle (100 microl, i.m., of cottonseed oil). Two other groups of rats were treated with alpha-zearalenol or 17beta-estradiol plus the pure estrogen receptor antagonist ICI 182780 (2.5 mg/kg/day, i.m., for 4 weeks). Mean arterial blood pressure (MAP), heart rate (HR), total plasma cholesterol, plasma estradiol, and plasma alpha-zearalenol were studied. We also investigated endothelial-dependent (acetylcholine, 10 nM to 10 microM) and endothelial-independent (sodium nitroprusside, 15 nM to 30 nM) relaxation of aortic rings, as well as N(G)-methyl-L-arginine (L-NMA: 10 to 100 microM)-induced vasoconstriction and calcium-dependent nitric oxide synthase (cNOS) activity in homogenates of lungs taken from both sham OVX rats and OVX rats. Untreated OVX rats had, compared with sham OVX animals, unchanged body weight, MAP, HR, and plasma cholesterol. In contrast oophorectomy reduced plasma estradiol levels (OVX, 2 +/- 0.5 pg/ml; sham OVX, 35 +/- 6 pg/ml), impaired endothelial-dependent relaxation and blunted L-NMA-induced contraction (L-NMA 100 microM: sham OVX, 2.7 +/- 0.3 g/mg tissue; OVX, 1.3 +/- 0.1 g/mg tissue). Moreover OVX rats showed a reduced calcium-dependent NO synthase (cNOS) activity. Treatment with alpha-zearalenol or with 17beta-estradiol reverted the endothelial dysfunction and increased cNOS activity in lung homogenates. These effects were abolished by the pure estrogen receptor antagonist ICI 182780. Our data suggest that alpha-zearalenol improves endothelial-dependent relaxation in OVX rats through an estrogen receptor-mediated effect.

Association of circulating cellular adhesion molecules with menopausal status and hormone replacement therapy. Time-dependent change in transdermal, but not oral estrogen users

The incidence of coronary heart disease is lower in premenopausal than in postmenopausal women, and estrogen use may be cardioprotective among postmenopausal women. Cellular adhesion molecules (CAM) are involved in the early stage of atherosclerosis, and short-term administration of oral estrogen decreased plasma concentrations of their soluble forms in postmenopausal women. However, data evaluating transdermal estrogen are sparse and long-term effect of hormone replacement therapy (HRT) on CAM is unknown. Therefore, we have investigated the association of circulating CAM (cCAM) with menopausal status and long-term HRT. Plasma levels of intercellular adhesion molecule-1 (cICAM-1), vascular cell adhesion molecule-1 (cVCAM-1), P-selectin, E-selectin, C-reactive protein (CRP), and fibrinogen were measured in 74 premenopausal women, 60 postmenopausal women not using HRT, 30 postmenopausal women using opposed oral estrogen therapy, and 30 postmenopausal women using opposed transdermal estrogen therapy. All women were apparently healthy and aged between 45 and 54 years. Duration of HRT ranged from 3 to 96 months. Postmenopausal women not receiving HRT had 24% higher mean levels of cICAM-1 than premenopausal women (318 vs. 255 ng/ml, P < .001). In postmenopausal women, users of oral estrogen had 16% lower, and users of transdermal estrogen had 17% lower mean levels of cICAM-1 than non-users (268 and 264 vs. 318 ng/ml, P = .001 for both comparisons). Furthermore, in users of transdermal route, the lowering effect of estrogen on cICAM-1 was dependent on treatment duration, while no time-dependent effect was seen in oral estrogen users. Users of transdermal estrogen had lower cVCAM-1 and P-selectin levels than postmenopausal non-users (327 vs. 364 ng/ml (P = .05) and 18 vs. 23 ng/ml (P = .05). There was no difference in CRP and E-selectin levels between the groups. Adjustment for age and body mass index (BMI) made no substantial change in the results. These data suggest that oral and transdermal estrogen may play a long-term cardioprotective role through favourable changes in endothelial function.

The role of CBP in estrogen receptor cross-talk with nuclear factor-kappaB in HepG2 cells

Functional interactions or cross-talk between ligand-activated nuclear receptors and the proinflammatory transcription factor nuclear factor-kappaB (NF-kappaB) may play a major role in ligand-mediated modification of diseases processes. In particular, the cardioprotective effects of estrogen replacement therapy are thought to be due in part to the ability of ligand-bound estrogen receptor (ER) to inhibit NF-kappaB function. In the current study 17beta-estradiol-bound ERalpha interfered with cytokine-induced activation of a NF-kappaB reporter in HepG2 cells. The estrogen metabolite, 17alpha-ethinyl estradiol, and the phytoestrogen, genistein, were also effective inhibitors of NF-kappaB activation, whereas tamoxifen, 4-hydroxytamoxifen, and raloxifene were inactive. This inhibition was reciprocal, as NF-kappaB interfered with the trans-activation properties of ERalpha. Ligand-bound ERalpha did not inhibit NF-kappaB binding to DNA, but it did decrease the histone acetyltransferase activity required for NF-kappaB transcriptional activity. Coexpression of the transcription coactivator CREB binding protein (CBP), but not steroid receptor coactivator 1a, reversed the ERalpha-mediated inhibition of NF-kappaB activity. Mammalian two-hybrid experiments also revealed that ligand-bound ERalpha can interact functionally with CBP-NF-kappaB complexes. We suggest that CBP targeting by ERalpha results in the inhibition of NF-kappaB and may occur through formation of transcriptionally inert multimeric complexes that are dependent upon the nature of the ERalpha ligand.

Direct vascular effects of estrogens and selective estrogen receptor modulators

The aim of this review is to provide an update on the latest advancements in the field of the action of estrogens on the cardiovascular system, and particularly on the molecular mechanisms of the direct effects of these hormones and of some of the new synthetic selective estrogen receptor modulators on the vascular wall.

Short-term hormone replacement therapy: reduced plasma levels of soluble adhesion molecules

BACKGROUND

Epidemiological data have suggested that the use of hormone replacement therapy (HRT) is associated with a decreased risk of cardiovascular disease. Vascular endothelium and adhesion molecules play an important role in the initiation and progression of atherosclerosis.

MATERIAL AND METHODS

Prospective, randomized, placebo-controlled 12-week study. Sixty healthy, normotensive postmenopausal women received either micronised oestradiol 2 mg alone (n = 16, E2 group), or sequentially combined with a progestagen; E2 + P groups trimegestone 0.5 mg (E2 + T, n = 14) or dydrogesterone 10 mg (E2 + D group, n = 14) or placebo (n = 16). Data were collected at baseline and at 4 and 12 weeks.

RESULTS

Twelve weeks of treatment with E2 or E2 + P was associated with a significant decrease in the plasma concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), and thrombomodulin (sTM). The average decrease in these markers was about 9%. In women treated with trimegestone the decreases were larger than in those treated with dydrogesterone; for sICAM-1 (-15% vs. -2%; P < 0.0001), sVCAM-1 (-15% vs. +3%; P = 0. 003) and sTM (-9% vs. -4%; P = 0.11). Plasma levels of endothelin-1 (ET-1) decreased (by 13%) only in women treated with E2 + P. In the E2 group, flow-mediated, endothelium-dependent vasodilatation increased by 6 percentage points after 12 weeks (P = 0.07 vs. baseline, P = 0.02 vs. E2 + P, and P = 0.17 vs. placebo).

CONCLUSION

Short-term treatment with E2 or E2 + trimegestone reduces plasma levels of sICAM-1, sVCAM-1 and sTM. ET-1 decreased only in the E2 + P groups. Different types of progestagens may differentially affect sICAM-1, sVCAM-1 and sTM levels, which may be relevant for the choice of type HRT.