Postmenopausal hormone replacement, risk estimators for coronary artery disease and cardiovascular protection

Energy Metabolism Changes and Dysregulated Lipid Metabolism in Postmenopausal Women

Aging women experience hormonal changes, such as decreased estrogen and increased circulating androgen, due to natural or surgical menopause. These hormonal changes make postmenopausal women vulnerable to body composition changes, muscle loss, and abdominal obesity; with a sedentary lifestyle, these changes affect overall energy expenditure and basal metabolic rate. In addition, fat redistribution due to hormonal changes leads to changes in body shape. In particular, increased bone marrow-derived adipocytes due to estrogen loss contribute to increased visceral fat in postmenopausal women. Enhanced visceral fat lipolysis by adipose tissue lipoprotein lipase triggers the production of excessive free fatty acids, causing insulin resistance and metabolic diseases. Because genes involved in β-oxidation are downregulated by estradiol loss, excess free fatty acids produced by lipolysis of visceral fat cannot be used appropriately as an energy source through β-oxidation. Moreover, aged women show increased adipogenesis due to upregulated expression of genes related to fat accumulation. As a result, the catabolism of ATP production associated with β-oxidation decreases, and metabolism associated with lipid synthesis increases. This review describes the changes in energy metabolism and lipid metabolic abnormalities that are the background of weight gain in postmenopausal women.

Serum uric acid concentration is associated with hypertensive retinopathy in hypertensive chinese adults

BACKGROUND

This cross sectional investigation included 12,966 subjects with hypertension, a cohort of the China Stroke Primary Prevention Trial (CSPPT), a randomized, multicenter clinical trial. This study aimed to explore the correlation between serum uric acid (SUA) concentration and hypertensive retinopathy in hypertensive adults.

METHODS

Diagnosis of hypertensive retinopathy was determined by non-mydriatic fundus photography and classified with Keith-Wagener-Barker (KWB) system. The correlation of SUA levels with hypertensive retinopathy prevalence and severity was assessed by statistical analysis.

RESULTS

9848 (75.95%) subjects were diagnosed with hypertensive retinopathy with the following retinopathy grade distribution: grade 1: 58.80%, grade 2: 14.81%, and grade 3-4: 2.34%. SUA levels were significantly associated with hypertensive retinopathy prevalence. Patients with hypertensive retinopathy had higher SUA levels than those without hypertensive retinopathy. Patients in the highest uric acid quartile had an odds ratio for hypertensive retinopathy of 1.21 compared to patients in the lowest uric acid quartile (OR = 1.21, 95% CI: 1.05-1.40, P = 0.008). When compared to the non-hyperuricemia group, those in the hyperuricemia group had an odds ratio for hypertensive retinopathy of 1.18(OR = 1.18, 95% CI: 1.05-1.33, P = 0.004). Every 1 mg/dl increase in uric acid concentration was significantly associated with a 6% higher odds of hypertensive retinopathy (OR = 1.06, 95% CI: 1.02-1.10, P = 0.002).

CONCLUSIONS

The prevalence of hypertensive retinopathy was high (75.95%) among hypertensives in our patients cohort. In addition, SUA concentration was significantly associated with hypertensive retinopathy.

Hemostatic disorders of the menopausal period: the role of microRNA

Adverse changes in hemostasis of menopausal women, observed e.g. in atherosclerotic or neoplastic cases, are of multicausal origin. It is believed that in the development and regulation of these processes, an important role is played by microRNA particles, which presence is ascertained in endothelial cells, atherosclerotic plaques and systemic circulation. Discovered for the first time over 20 years ago, up to now over two and a half thousand types of microRNA have been identified in the human body. MicroRNAs are single stranded RNA molecules of 20-24 nucleotides, encoded by the cell's genome and then transcribed by polymerase II. They regulate the expression of a large gene pool, approximately 30% of all genes, in the human body. MicroRNA molecules, like other bioactive molecules – RNA, protein – both play important roles in tumor invasion, metastasis, inflammation, coagulation, and regeneration. What is important, they can be detected not only in tissues (e.g. tumor tissues), but also in circulation (blood serum), where they are released. Accurate understanding of the role played by certain types of microRNA (e.g. miR-126, miR-17-92, miR-33, miR-613, miR-27a/b, miR-143, miR-335, miR-370, miR-122, miR-19b, miR-520, or miR-220) in hemostatic processes may allow in the future for their use not only as specific biomarkers of cardiovascular diseases but also as the target for innovative gene therapies.

Hormone Replacement Therapy: A Critical Review

The aim of this chapter is to review the most recent aspects of hormone replacement therapy (HRT), and to clarify its impact on associated health conditions amidst growing uncertainties. Special emphasis has been placed on its effect on cardiovascular conditions and breast cancer, the two most important outcomes affected by HRT, and on identifying ideal candidates for HRT as well as defining the optimum new HRT regimens.

Plasma free fatty acid level patterns according to cardiovascular risk status in postmenopausal women

BACKGROUND

The present study examines changes in the pattern of plasma free polyunsaturated fatty acids (PUFA) according to menopausal status and the existence of diabetes mellitus (DM) or coronary heart disease (CHD) in Korean women.

METHODS

The participants were as follows; premenopausal women (PRE, n=20) and postmenopausal women without any known chronic disease (POST, n=35), with DM (DM, n=35), or with angiographically proven CHD (CHD, n=30). Plasma free fatty acids were measured in all participants.

RESULTS

Healthy premenopausal women had a higher ratio of omega-3/omega-6 PUFA than postmenopausal women (p=0.001). As expected, the PRE group had higher docsapentaenoic acid (DPA) and docosahexaenoic acid (DHA) levels (p<0.05) and lower arachidonic acid levels (p<0.05) than the POST group. In turn, the healthy POST group had higher levels of DPA and DHA compared to the DM or CHD groups (p<0.05). There were significant shifts of increased omega-6 and decreased omega-3 among the women, according to each disease.

CONCLUSIONS

There was a significant relationship between omega-3 and omega-6 PUFA profiles and risk for CHD in women. This metabolic profile of PUFA might be an important surrogate marker in postmenopausal women.

Effects of non-oral postmenopausal hormone therapy on markers of cardiovascular risk: a systematic review

OBJECTIVE

To review the effects of non-oral administration of postmenopausal hormone therapy (HT) on risk markers for atherosclerotic and venous thromboembolic disease.Non-oral postmenopausal HT appears not to increase venous thromboembolic risk, whereas the effect on coronary heart disease risk is less clear.

DESIGN

Systematic review of literature obtained from MEDLINE, EMBASE, and CENTRAL databases from 1980 until and including April 2006. Terms for "postmenopausal hormone therapy" and for "non-oral administration" were combined in the search.

SETTING

Randomized clinical trials.

PATIENT(S)

Postmenopausal women, both healthy and with established cardiovascular disease or specified cardiovascular risk factors

INTERVENTION(S)

Non-oral HT (e.g., transdermal or intranasal) compared with oral HT or no treatment/placebo.

MAIN OUTCOME MEASURE(S)

Lipoprotein(a), homocysteine, C-reactive protein (CRP), cell adhesion molecules, markers of endothelial dysfunction, coagulation, and fibrinolysis.

RESULT(S)

Seventy-two studies investigating either transdermal or intranasal administration were included. For non-oral HT, decreases in lipoprotein(a), cell adhesion molecules, and factor VII generally were significant, resistance to activated protein C (APCr) was slightly increased, and other markers including CRP and homocysteine did not change. Compared with oral HT, changes in CRP and APCr were smaller, changes in cell adhesion molecules and some fibrinolytic parameters tended to be smaller, whereas changes in other factors including lipoprotein(a) and homocysteine did not differ.

CONCLUSION(S)

Potentially unfavorable changes seen with oral HT on two important markers, CRP and APCr, are substantially smaller with non-oral HT. Non-oral HT has minor effects on the other cardiovascular risk markers studied. Therefore, compared with oral HT, non-oral HT appears be safer with respect to atherosclerotic and venous thromboembolic disease risk.

Low-dose hormone therapy in the perimenopause

OBJECTIVE

To evaluate the effects of low-dose hormone therapy (LD-HT) on bleeding pattern and vasomotor symptoms in perimenopausal women.

METHODS

In a prospective, open-label study at an University clinic, 120 perimenopausal women suffering from irregular menstrual cycles and hot flushes were randomized to micronized 17beta-estradiol 1 mg plus dydrogesterone 10 mg sequential added (LD-HT; group A: 60 subjects) or dydrogesterone 10 mg from day 15 to 28 (group B: 60 subjects). Number and severity of hot flushes and bleeding pattern were assessed throughout the study.

RESULTS

Women in group A experienced a significant reduction in number of hot flushes while no significant variation was observed in group B. The incidence of cyclic bleeding was 86% in group A and 76% in group B, the mean duration was significantly lower in group A than in group B.

CONCLUSIONS

LD-HT may control both irregular bleeding and hot flushes in perimenopausal women.

The effect of various menopausal hormone therapies on markers of inflammation, coagulation, fibrinolysis, lipids, and lipoproteins in healthy postmenopausal women

OBJECTIVE

Androgenic progestins such as norethisterone acetate (NETA) may influence the effect of estradiol (E(2)) therapy. We compared the influence of oral E(2), with and without NETA, and transdermal E(2) on markers of coagulation, fibrinolysis, and inflammation and on lipids and lipoproteins in healthy postmenopausal women.

DESIGN

A total of 112 healthy postmenopausal women were randomized to receive treatment with either oral E(2), with or without NETA, transdermal E(2), or placebo. At baseline and after 28 weeks, levels of serum lipids and lipoproteins and markers of coagulation, fibrinolysis, and inflammation were determined.

RESULTS

Of the fibrinolytic parameters, oral E(2) (P < 0.05) and E(2) with NETA (P < 0.01) shortened euglobulin clot lysis time. Oral E(2) decreased plasminogen activator inhibitor-1 activity (P < 0.05). Oral E(2) with NETA reduced plasminogen activator inhibitor-1 antigen levels (P < 0.01) and increased D-dimer antigen levels (P < 0.001). All three modes of menopausal hormone therapy reduced tissue type plasminogen activator antigen. Of the coagulation parameters, both routes of E(2) therapy decreased fibrinogen levels (P = 0.002 for oral and P = 0.007 for transdermal E(2)), whereas E(2) with NETA showed no effect. The decrease of fibrinogen was larger after oral E(2) (P = 0.02). Oral E(2) with NETA reduced antithrombin III (P < 0.001) and protein C (P < 0.001) activity. Oral E(2) (P = 0.04) and E(2) with NETA (P < 0.01) increased C-reactive protein (CRP). Transdermal E(2) showed no influence on CRP. The addition of NETA influenced the change in CRP, as the increase in CRP was more pronounced after E(2) without NETA (P = 0.005). The levels of serum amyloid A, interleukin-6, and tumor necrosis factor-alpha did not change significantly after any of the modes of hormone therapy. Of the lipids and lipoproteins, oral E2 decreased low-density lipoprotein cholesterol (P < 0.01), lipoprotein (a) (P < 0.05), and increased high-density lipoprotein cholesterol (P < 0.05). Transdermal E(2) decreased triglycerides (P < 0.02) and increased high-density lipoprotein cholesterol (P < 0.03). Oral E(2) with NETA decreased total cholesterol (P < 0.01) and high-density lipoprotein cholesterol (P < 0.005).

CONCLUSIONS

Oral E(2), with or without NETA, produced no net activation of coagulation but improved fibrinolysis. Both modes of oral menopausal hormone therapy have a greater impact on markers of inflammation, coagulation, fibrinolysis, lipids, and lipoproteins than transdermal E(2). NETA attenuates some E(2) effects. Further studies are needed to elucidate the impact of these effects on clinical endpoints.

Apo e4 allele is associated with endothelium-dependent arterial dilation in women with type 2 diabetes

OBJECTIVE

Previous studies have suggested that the e4 allele of apolipoprotein E (apo E) relates to the endothelium-dependent arterial dilation in men with type 2 diabetes. This study attempted to assess whether apo e4 allele is associated with endothelial dysfunction in women with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We selected 144 Chinese Han female type 2 diabetic patients without clinically detectable angiopathy. Polymerase chain reaction/ASO probes were used to determine their mouthwash DNA apo E genotypes, and high-resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperemia (with increased flow causing endothelium-dependent dilation) and after sublingual glyceryltrinitrate (GTN, an endothelium-independent dilator).

RESULTS

The flow-mediated arterial dilation among the subjects with e4/3 or e4/4 was 3.56+/-0.23%, which was significantly lower than that in subjects with e2/2 or e3/2 (3.97+/-0.36%) (p=0.000). The baseline vessel size, GTN-induced dilation and baseline blood flows were not significantly different among different apo E genotypes. On univariate analysis, reduced flow-mediated arterial dilation was significantly related to total cholesterol, LDL, Lp(a), high blood pressure, older age, family history of premature vascular disease, larger vessel size, duration of diabetes and e4 allele (p<0.05). By multiple stepwise regression analysis, reduced flow-mediated arterial dilation was associated with older age, large vessel size, duration of diabetes, positive family history, LDL, Lp(a) and e4 allele (p<0.01).

CONCLUSION

The apo e4 allele is associated with impairment of endothelium-dependent arterial dilation in the relatively early stage of female type 2 diabetes.

The effect of raloxifene and tibolone on the uterine blood flow and endometrial thickness: A transvaginal Doppler study

OBJECTIVES

To evaluate and compare the effect of different than classical hormone therapy medications, such as raloxifene and tibolone, on the uterine arteries and endometrium of postmenopausal women using transvaginal ultrasonography.

METHODS

The prospective study included 62 healthy, postmenopausal women recruited from the Menopausal Clinic of the 2nd Department of Obstetrics and Gynecology of the University of Athens. Subjects were randomly allocated to receive raloxifene HCl in a daily dose of 60 mg orally (Group A-31 women) or tibolone in a daily dose of 2.5 mg orally (Group B-31 women). The study period was 6 months and all subjects were assessed using transvaginal ultrasonography before treatment initiation as well as after 3 and 6 months for evaluation of the endometrial thickness and the pulsatility (PI) and resistance (RI) indices at the level of the uterine arteries.

RESULTS

No significant differences in RI, PI and endometrial thickness were observed in the raloxifene group during the 6-month treatment. In the tibolone group, PI and RI values decreased linearly from baseline to the end of the study, whereas the endometrial thickness was significantly increased during the first 3 months remaining unaltered thereafter. Comparisons between the two study groups revealed significant percent change of values in the pre-treatment to month-3 period and no difference with regard to pre-treatment, month-3 and month-6 absolute values.

CONCLUSION

Raloxifene and tibolone exert dissimilar effects on uterine blood supply parameters and endometrial thickness.

Behaviour of some indicators of oxidative stress in postmenopausal and fertile women

OBJECTIVE

Unsaturated fatty acids are known to have a crucial role in the pathogenesis of atherosclerosis. They are very sensitive to oxidation caused by excess free oxygen radicals and the consequent oxidative status, and it is well known that lipid and lipoprotein metabolism is markedly altered in postmenopausal women. Oxidative stress is involved in the pathophysiology of atherosclerosis and our study aim was to assess the presence of such stress in postmenopausal women.

DESIGN

One hundred and one women were enrolled in the study. Fifty were fertile (32.5+/-1.1 years) with regular menses and fifty-one were postmenopausal women (52.1+/-1.3 years). None of the study cohort had ever used hormone replacement therapy. Malonaldehyde (MDA), 4-hydroxynenal (4-HNE), oxidized lipoproteins (ox LDL) and glutathione peroxidase (GSH-PX) values were determined as we believe they reveal oxidative stress.

RESULTS

MDA, 4-HNE and ox LDL concentrations were higher in postmenopausal than fertile women (p<0.001), while GSH-PX concentrations were significantly higher in fertile women than in postmenopausal subjects (p<0.001).

CONCLUSIONS

Our data revealed the presence of oxidative stress in postmenopausal women.

Emerging Selective Estrogen Receptor Modulators

Menopause, regardless of age at onset, is associated with a marked increase in coronary heart disease (CHD) risk. On the basis of epidemiological studies that demonstrated mainly positive effects of postmenopausal hormone therapy on CHD as well as on risk markers of CHD, it has been suggested that CHD could be prevented in postmenopausal women with long-term hormone therapy. However, since the publications of the Heart and Estrogen/progestin Replacement Study and the Women's Health Initiative trial, prescription of hormone therapy for the prevention of CHD has become controversial. Major efforts have been made to identify alternatives for hormone therapy. Compounds suggested have included selective estrogen receptor modulators (SERMs), which represent a class with a growing number of compounds that act as either estrogen receptor agonists or antagonists in a tissue-specific manner. This pharmacological profile may offer the opportunity to dissociate favourable estrogenic effects on the bone and cardiovascular system from unfavourable stimulatory effects on the breast and endometrium. Two SERMs presently on the market are tamoxifen and raloxifene. The only data available regarding the effects of tamoxifen on cardiovascular events in postmenopausal women are from breast cancer trials. These trials found fewer fatal myocardial events in women randomly assigned to tamoxifen compared with women assigned to placebo. Raloxifene is a second-generation SERM that has been shown to prevent osteoporotic fractures, is safe for the endometrium and holds high promise for the prevention of breast cancer. The effect of raloxifene on CHD is still uncertain. On the basis of the MORE (Multiple Outcomes of Raloxifene Evaluation) trial, raloxifene may offer some protection to women with CHD or to those who are at high risk of CHD. Proof that raloxifene reduces the risk of CHD requires a clinical trial with hard clinical endpoints. Such a study is currently underway. Next-generation SERMs taken into clinical development include idoxifene, droloxifene, ospemifene, arzoxifene, acolbifene/EM-800, levormeloxifene, lasofoxifene, bazedoxifene and HMR 3339. The aim is to find a compound with the ideal profile, that is, alleviation of climacteric symptoms and prevention of osteoporotic fractures, but without an adverse effect on the breast and endometrium, and no negative effect or even a beneficial effect on the cardiovascular system and the brain. Currently, limited data are available with regard to these next-generation SERMs and CHD. Nevertheless, some of these novel agents provide arguments for continuing the search for an ideal SERM.

Apolipoprotein e4 allele and the risk of CAD death in type 2 diabetes mellitus with ischaemia electrocardiographic change

The presence of apolipoprotein (Apo) e4 allele is reported to be associated with the increased risk of coronary artery disease (CAD), as well as the impairment of endothelium-dependent arterial dilation in type 2 diabetes mellitus. Therefore, we hypothesized that Apo e4 allele increases the death risk from coronary artery disease in type 2 diabetes with ischaemia electrocardiographic change. From January 1993 to December 1999, 46 type 2 diabetic patients with e4/4 or e4/3, 96 with e3/3 and 45 with e2/2 or e3/2 genotypes were recruited. All subjects were unrelated elderly type 2 diabetic patients with ischaemia electrocardiographic change, aged 60-87 years, and their cardiac function were all the class I stage at their time of enrollment. A follow-up study of 3-10 years was undergone. The results are as follows: At baseline, serum total cholesterol and low-density lipoprotein (LDL) cholesterol concentrations were higher in subjects with e4/3 or e4/4 than in subjects with e2/2 or e3/2 (p<0.05). Lipoprotein(a) concentration was lower in subjects with e2/2 or e3/2 than in subjects with e3/3 and e4/3 or e4/4 (p < 0.05). During the 3-10 years follow-up period, a total of 55 patients who died from CAD were recorded in this sample. Compared with patients with e3/3 (p = 0.024) and patients with e2/2 or e2/3 genotypes (p = 0.002), the mortality rate of CAD in patients with e4/3 or e4/4 genotypes was the highest (47.8%). Stepwise discriminant analysis revealed that in the diabetic population studied Apo e4 allele was independently and significantly associated with CAD death (B = 0.65). However, the strength of the association decreased (B = 0.44) when total cholesterol, LDL-cholesterol and lipoprotein(a) were included in the model. Therefore, we concluded that Apo e4 allele increases the risk of CAD death in elderly type 2 diabetes mellitus with ischaemia electrocardiographic change.

Hormone replacement therapy and cardiovascular risk

Hormone replacement therapy (HRT) is effective in suppressing postmenopausal symptoms and, in the past, many have claimed that it is cardioprotective. It was thought that the lower incidence of cardiovascular disease in premenopausal women was related to the cardioprotective effect of estrogen. Many of these studies were, however, observational studies. HRT alters many cardiovascular parameters, most beneficially. The mixed effect on these parameters make the overall result on cardiovascular risk difficult to predict. However, recent randomized, placebo-controlled trials have shown not only that HRT does not confer cardioprotection, but that it actually increases one's cardiovascular risk in the short term. Based on the current evidence, HRT should not be recommended in the hope that it will protect postmenopausal women against coronary heart disease.

Hormone replacement therapy, selective estrogen receptor modulators, and tissue-specific compounds: cardiovascular effects and clinical implications

In industrialized countries, coronary heart disease (CHD) is not only the leading cause of death in women but of disability as well. Menopause, regardless of age at onset, is associated with a marked increase in CHD risk. Based on epidemiologic studies demonstrating mainly positive biologic effects of hormone replacement therapy (HRT) on CHD risk factors and outcomes, earlier recommendations decreed that most, if not all, postmenopausal women should be treated with long-term HRT. Recent randomized controlled trials with clinical CHD endpoints have shown that previously held dicta may not be accurate. Selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene are alternatives to HRT. SERMs represent a growing class of compounds that act as either estrogen receptor agonists or antagonists in a tissue-selective manner. This pharmacologic profile may offer the opportunity to dissociate favorable cardiovascular effects of estrogen from unfavorable stimulatory effects on the breast and endometrium. The only data available regarding the effects of tamoxifen on cardiovascular events in postmenopausal women are from breast cancer trials. They showed fewer fatal myocardial events in women randomly assigned to tamoxifen compared with women assigned to placebo. Raloxifene is a so-called second-generation SERM. It seems clear that raloxifene increases bone mineral density, has no effect on the endometrium, and holds high promise for the prevention of breast cancer. The effect of raloxifene on cardiovascular disease is uncertain. On the basis of the Multiple Outcomes of Raloxifene Evaluation (MORE) trial, raloxifene may offer some protection to women with cardiovascular disease or to those who are at high risk. Proof that raloxifene reduces the risk of CHD requires a clinical trial with hard clinical endpoints. Such a study is currently underway. Clinical trials have demonstrated that the synthetic 19-nortestosterone derivative tibolone reduces climacteric complaints and prevent osteoporosis without causing menstrual bleeding. Tibolone lowers lipoprotein(a), fibrinogen, and plasminogen activator inhibitor-1 levels and improves glucose tolerance, insulin sensitivity, and endothelial function; however, it also lowers high-density lipoprotein cholesterol by >20%. The long-term impact of tibolone on the risk of CHD is not known and needs to be studied.

Apolipoprotein e4 allele is predictor of coronary artery disease death in elderly patients with type 2 diabetes mellitus

The presence of the apolipoprotein (Apo) e4 allele is reported to be associated with the increased risk of coronary artery disease (CAD), as well as the impairment of endothelium-dependent dilation in type 2 diabetes mellitus. Therefore, we hypothesized that the Apo e4 allele increases the death risk from coronary artery disease in type 2 diabetes. From January 1993 to December 1999, 36 type 2 diabetic patients with e4/4 or e4/3, 62 with e3/3 and 33 with e2/2 or e3/2 genotypes were recruited. All subjects were unrelated, elderly, type 2 diabetic patients with coronary artery disease, aged 60-84 years, with cardiac function at the Class I stage at time of enrollment. A follow-up study of 3-10 years was undergone. The results are as follows: At baseline, serum total cholesterol and low density lipoprotein (LDL) cholesterol concentrations were higher in subjects with e4/3 or e4/4 than in subjects with e2/2 or e3/2 (P = 0.026). Lipoprotein(a) concentration was lower in subjects with e2/2 or e3/2 than in subjects with e3/3 (P = 0.044) and e4/3 or e4/4 (P = 0.038). During the 3-10 years follow-up period, a total of 39 patients who died from CAD was recorded in this sample. Compared with patients with e3/3 (P = 0.030) and patients with e2/2 or e3/2 genotypes (P = 0.001), the mortality rate of CAD in patients with e4/3 or e4/4 genotypes was the highest (50%). Stepwise discriminant analysis revealed that in the diabetic population studied the Apo e4 allele was independently and significantly associated with CAD death (B = 0.64). However, the strength of the association decreased (B = 0.48) when total cholesterol, LDL-cholesterol and lipoprotein(a) were included in the model. Therefore, we concluded that Apo e4 allele increases the risk of CAD death in elderly patients with type 2 diabetes mellitus.

Effect of hormone replacement therapy, tibolone and raloxifene on serum lipids, apolipoprotein A1, apolipoprotein B and lipoprotein(a) in Greek postmenopausal women

The aim of this study was to assess the effect of estrogen, two regimens of continuous combined hormone replacement therapy (HRT), tibolone and raloxffene on serum lipid, apolipoprotein A1 and B and lipoprotein(a) levels in Greek postmenopausal women. A total of 350 postmenopausal women were studied in a prospective open design. Women were assigned to one of the following regimens depending on the presence of risk factors for osteoporosis, dimacteric symptoms and an intact uterus: conjugated equine estrogen 0.625 mg (CEE, n = 34), continuous combined CEE 0.625 mg plus medroxyprogesterone acetate (MPA) 5 mg, (n = 80), continuous combined 17beta-estradiol 2 mg plus norethisterone acetate (NETA) 1 mg (n = 58), tibolone 2.5 mg (n = 83) and raloxifene HCl 60 mg (n = 50). Forty-five postmenopausal women with no indications for HRT served as controls. Total cholesterol (TC), low-density lipoprotein (LDL) cholestrol and high-density lipoprotein (HDL) cholesterol, triglyceride (TG), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and lipoprotein(a) (Lp(a)) levels were assessed in each subject at baseline, and at 6 and 12 months of therapy. All therapy regimens lowered TC levels compared to baseline (4.2-8.0% decrease). This effect was more prominent in the subgoup of women with high baseline TC levels (9.1-20.4% decrease). LDL cholesterol decreased significantly in CEE, CEE/MPA and raloxifene groups (-11.2%, -11.9% and -11.0%, respectively). Hypercholesterolemic women exhibited a steeper decrease in LDL cholesterol (10.6-27.8% in all therapy groups). TG levels increased significantly in the CEE and CEE/MPA groups (23.7% and 21.8%, respectively), while estradiol/NETA had no effect on TG levels. Tibolone decreased TG levels markedly, by 20.6%, while raloxifene had no TG-lowering effect. HDL cholesterol and ApoA1 were increased by CEE and CEE/MPA (HDL cholesterol, 7.4% and 11.8%, respectively; ApoA1, 17.8% and 7.9%, respectively) and decreased by tibolone (HDL cholesterol, -13.6%; and ApoA1, -9.9%). All therapy regimens except raloxifene lowered Lp(a) levels, with tibolone having the more pronounced effect (-13.2 to -29.0%). In conclusion, each therapy regimen had a diferent effect on lipid-lipoprotein levels, exerting favorable and unfavorable modifications. Hypercholesterolemic women seemed to benefit more from the cholesterol-lowering effect of estrogen replacement therapy/HRT. The choice for a particular regimen should be based on individual needs, indications and lipid-lipoprotein profile.

Effect of hormone replacement therapy and tibolone on serum total homocysteine levels in postmenopausal women

OBJECTIVE

To assess the effect of continuous combined hormone replacement therapy (HRT) or tibolone on serum total homocysteine (tHcy) levels in postmenopausal women.

STUDY DESIGN

Ninety-five postmenopausal women aged 41-68 years were included in the study. Seventy-three women with climacteric complaints, osteopenia or osteoporosis received either conjugated equine estrogens 0.625 mg combined with medroxyprogesterone acetate 5 mg (CEE/MPA, n=31) or tibolone 2.5 mg (n=42). Twenty-two healthy women, matched for chronological and menopausal age, served as controls. Serum tHcy levels were assessed at baseline, 6, 12 and 18 months.

RESULTS

No difference was recorded between groups regarding demographic characteristics or mean baseline serum tHcy. Serum tHcy levels decreased significantly in the CEE/MPA compared to baseline (change at 18 months: -3.9%, P<0.05). The magnitude of the decrease was higher in the subgroup of women with baseline tHcy levels above the median (change at 18 months: -15.0%, P<0.01). No change in tHcy levels was detected in the tibolone group throughout the study period, either in the whole group (change at 18 months: 1.9%, NS) or in the subgroup with baseline tHcy levels above the median (change at 18 months: -3.23%, NS).

CONCLUSION

Continuous CEE/MPA reduces tHcy especially in women with high pretreatment tHcy levels. Tibolone has no effect on serum tHcy levels at least during the first 18 months of therapy. Larger studies with longer follow-up are required to confirm these results.

Menopause, the Cardiovascular Risk Factor Homocysteine, and the Effects of Treatment

Since the identification of homocysteine (Hcy) as a risk factor for cardiovascular disease, it has been the subject of much research. As with other cardiovascular risk factors, a gender difference exists for Hcy. Plasma levels are lower in women of reproductive age than in men and postmenopausal women. This has led to the hypothesis that the increased risk of cardiovascular disease documented in postmenopausal women may be related to the increase in Hcy levels. Factors affecting total plasma levels of Hcy include genetic factors, nutritional factors, and lifestyle. Many studies appear to support the ability of estrogen replacement therapy to significantly lower both basal levels of Hcy and levels following methionine loading. A mean reduction of 10-15% in Hcy levels after 6 months of hormone therapy has been reported. Similarly, raloxifene and tamoxifen and low-dose folic acid administration induce reductions in plasma Hcy levels of the same degree observed for hormone therapy. The reduction occurs after a few months of therapy and is sustained, suggesting the potential for cardioprotective effects. Although there is a positive effect of estrogen therapy and hormone therapy on Hcy levels, recent studies do not recommend the use of estrogen or hormone replacement therapy for the primary or secondary prevention of cardiovascular disease. Further research is therefore needed to identify strategies to maximize the efficacy of hormone replacement therapy, while minimizing the risks.

Effects of oral and transdermal low-dose estrogen therapy on echocardiographic parameters of cardiac function

OBJECTIVE

To investigate the effects of transdermal 17 beta-estradiol (E(2)) compared with oral unopposed as well as opposed E(2) on echocardiographic parameters of left ventricular (LV) systolic and diastolic function.

DESIGN

A prospective, randomized, double-blind, placebo-controlled, multi-center study.

SETTING

Gynecologic and cardiologic outpatient departments.

PATIENT(S)

One hundred fifty-two healthy hysterectomized postmenopausal women.

INTERVENTION(S)

Participants received daily placebo (n = 49) or transdermal E(2) (50 microg; tE(2) group, n = 33), or oral E(2) (1 mg; oE(2) group, n = 37), or oral E(2) (1 mg) combined with gestodene (25 microg; oE(2)+G group, n = 33) for thirteen 28-day treatment cycles.

MAIN OUTCOME MEASURE(S)

M-mode, quantitative two-dimensional, and Doppler echocardiographic measurements were performed at baseline and after 1 year.

RESULT(S)

Compared with placebo, tE(2) and oE(2) showed no statistically significant changes in LV function. oE(2)+G resulted in a statistically significant favorable increase in peak flow velocity, flow velocity integral, and mean acceleration. Furthermore, a favorable decrease was observed in interventricular septum thickness and ejection time.

CONCLUSION(S)

After 1 year of unopposed E(2), LV function remained unchanged. The oE(2)+G treatment showed a potential beneficial influence on LV systolic function.

Serum lipids and apolipoproteins in Greek postmenopausal women: association with estrogen, estrogen-progestin, tibolone and raloxifene therapy

The aim of this study was to assess lipid and apolipoprotein levels in postmenopausal women taking various regimens of replacement therapy or no therapy. Seven hundred forty-eight postmenopausal women followed in the Menopause Clinic of the 2nd Department of Obstetrics and Gynecology, University of Athens, Aretaieion Hospital, were studied in a cross-sectional design. Women were either non-users of replacement therapy (no. = 511) or users of one of the following regimens: conjugated equine estrogen 0.625 mg (CEE, no. = 34), CEE 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, no. = 60), 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA, no. = 44), tibolone 2.5 mg (no. = 84), raloxifene HCI 60 mg (no. = 51). Total cholesterol (TC), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C), triglycerides (TG), apolipoprotein A1 (ApoA1) and apolipoprotein B (ApoB) levels were assessed. Women were grouped according to replacement regimen and mean levels of lipid and apolipoproteins were compared between groups. Women in the raloxifene group were older and longer menopaused. After adjustment for age and duration of menopause, TG levels were significantly lower in the tibolone and E2/NETA groups (75 and 89.9 mg/dl, respectively) compared to non-users. TC was lower in all therapy groups, but the difference acquired significance only in the E2/NETA (207.8 mg/dl), compared to non-users (231.5 mg/dl). LDL-C levels were significantly lower in the CEE (133.8 mg/dl), CEE/MPA (130.4 mg/dl) and raloxifene group (129.9 mg/dl) compared to non-users (151.9 mg/dl). There was no difference in HDL-C levels between users and non-users (58.9 mg/dl) except for the tibolone group where HDL-C was significantly lower (48.6 mg/dl). ApoA1 levels were significantly higher in the CEE/MPA group (194.4 mg/dl) and significantly lower in the tibolone group (141.6 mg/dl) compared to non-users (170.4 mg/dl). No difference was detected between groups concerning ApoB levels. In conclusion, tibolone therapy is associated with lower TG levels as well as lower HDL and ApoA1 levels. ERT, continuous combined estrogen-progestin therapy (HRT) and raloxifene are associated with lower LDL-C levels. Among continuous combined HRT users, CEE/MPA is associated with higher ApoA1 levels, while E2/NETA with lower TG levels. Large prospective randomized studies are required to validate these results.

Orally and transdermally replaced estradiol improves endothelial function equally in middle-aged women after surgical menopause

OBJECTIVE

Improvement in endothelial function may be an important mechanism by which estrogen replacement therapy protects postmenopausal women against coronary artery disease. We determined whether the vascular effects of estradiol depend on the route of administration.

STUDY DESIGN

Six weeks after surgically induced menopause, 43 healthy women were assigned randomly to 28 weeks of treatment by either orally or transdermally replaced estradiol. Endothelium-dependent and endothelium-independent dilation were calculated with the use of the diameters of the brachial artery that were measured at rest by high resolution ultrasound scanning after reactive hyperemia and after sublingual glyceryl trinitrate.

RESULTS

Endothelium-dependent dilation increased after oral estradiol replacement from 6% +/- 3.9% to 13.2% +/- 4.4% (P <.0001) and after transdermal estradiol replacement from 7% +/- 4.9% to 14.9% +/- 5.6%(P <.0001). Endothelium-independent dilation did not change significantly in either group. The improvements in endothelium-dependent dilation after estrogen substitution were independent of the changes in blood lipids and lipoproteins.

CONCLUSION

Both oral and transdermal long-term replacement of estradiol lead to improved endothelial function in healthy middle-aged women after surgically induced menopause.

Double blind, randomized study of estradiol replacement therapy on markers of inflammation, coagulation and fibrinolysis

Estrogen replacement therapy (ERT) has been found to be associated with increased cardiovascular risk in the first year after initiation of ERT. We compared the effects of oral and transdermal estradiol (E2) replacement therapy on markers of inflammation, coagulation and fibrinolysis in a randomized double-blind trial. Forty-three healthy women were randomized 6 weeks after surgically induced menopause to receive treatment with either oral or transdermal E2 over a period of 28 weeks. At baseline and after 28 weeks, levels of serum lipids and lipoproteins, and markers of coagulation, fibrinolysis and inflammation were determined. Among fibrinolytic parameters, oral E2 shortened euglobulin clot lysis time (P<0.05) and reduced tissue type plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor activity (P<0.05). Among coagulation parameters, both routes of E2 replacement decreased fibrinogen levels (P=0.002 for oral and P=0.007 for transdermal E2). Oral E2 resulted in an increase in C-reactive protein (CRP) from 2.15 (0.71-4.05) to 3.41 (1.12-5.92) mg/l (P=0.04), while transdermal E2 showed no effect. Levels of serum amyloid A (SAA), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) did not change significantly after oral and transdermal E2. Oral E2 significantly improved the lipid profile, while transdermal E2 had a less pronounced effect. Both oral and transdermal E2 significantly reduced fasting glucose. Oral E2 was associated with a pro-inflammatory response, but at the same time improved fibrinolytic capacity, showed no pro-coagulatory effects, and acted beneficially on lipids and lipoproteins. There was no influence of transdermal E2 on markers of coagulation activation, fibrinolysis and inflammation, but it decreased fibrinogen levels significantly. Further studies are needed to explore the clinical relevance of these observations.

Homocysteine, folic acid and B-group vitamins in obstetrics and gynaecology

The amino acid homocysteine is of considerable medical importance because it is involved in the etiopathogeny of cardiovascular diseases. Hyperhomocysteinemia is a factor in the vascular damage that predisposes thrombogenesis and arteriosclerosis. It has also been related to a range of obstetric and gynecologic complications. Numerous studies have demonstrated the association between increased levels of homocysteine and neural tube defects (NTD) and other congenital defects, spontaneous miscarriages, intrauterine growth retardation (IGR), preeclampsia and intrauterine fetal death. Folic acid and other B-group vitamins (B6 and B12) take part in the metabolism of homocysteine and the preventive administration of these vitamins may reduce some of the complications.

Apolipoprotein e4 allele and endothelium-dependent arterial dilation in Type 2 diabetes mellitus without angiopathy

AIMS/HYPOTHESIS

Several studies have suggested a predisposing role of the e4 allele of apolipoprotein E (ApoE) in the development of atherosclerosis and cardiovascular disease in Type 2 diabetes. Therefore, we hypothesized that the e4 allele is also a risk factor for endothelial dysfunction. We attempted to assess whether Apo e4 allele is associated with endothelial dysfunction in the early stage of Type 2 diabetes.

METHODS

We selected 255 Chinese Han Type 2 diabtetic men without angiopathy. PCR or allele-specific oligonucleotide probes were used to analyse ApoE genotypes, and high resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperaemia and after sublingual glyceryltrinitrate.

RESULTS

The flow-mediated arterial dilation among the subjects with e4/3 or e4/4 was 3.14+/-0.32%, which was lower than that in subjects with e2/2 or e3/2 (4.04+/-0.30%) ( p=0.038). The baseline vessel size, glyceryltrinitrate-induced arterial dilation and baseline flow were not different among different ApoE genotypes. On univariate analysis, reduced flow-mediated arterial dilation was related to total cholesterol, LDL, lipoprotein(a) [Lp(a)], high blood pressure, older age, family history of premature vascular disease, larger vessel size, cigarette smoking, duration of diabetes and e4 allele ( p<0.05). By multiple stepwise regression analysis, reduced flow-mediated arterial dilation was associated with cigarette smoking, LDL, Lp(a), and e4 allele ( p<0.01).

CONCLUSION/INTERPRETATION

Apo e4 allele is associated with impairment of endothelium-dependent arterial dilation in the early stage of Type 2 diabetes.

Homocysteine during the menstrual cycle in depressive women

BACKGROUND

Two possible factors that may have a causal relation with both depressive disorder and cardiovascular disease are elevated homocysteine and steroid hormones. Our previous study found significant changes in the plasma homocysteine concentration during the menstrual cycle in healthy women. The purpose of this study therefore was to test homocysteine in depressive women treated with fluoxetine during the menstrual cycle.

MATERIALS AND METHODS

Thirteen premenopausal women suffering from mixed anxiety-depressive disorder and a control group of 15 healthy women were enrolled in this study. The homocysteine concentration was determined by high-performance liquid chromatography with fluorescence detection, and estradiol, progesterone and cortisol by RIA methods.

RESULTS

We found significantly higher plasma homocysteine concentrations in the follicular phase than in the luteal phase of the menstrual cycle in both the depressive group (P < 0.003) and the controls (P < 0.0009). Moreover, the patient values of total homocysteine were significantly higher in the follicular phase (P < 0.03) and also in the luteal phase (P < 0.007) than the values of the controls. Estradiol and cortisol were significantly higher in the follicular phase of the patients compared with the control group.

CONCLUSION

According to our results, women suffering from mixed anxiety-depressive disorder have not only significantly different concentrations of homocysteine in the follicular and luteal phase of the menstrual cycle but also higher plasma homocysteine compared with healthy women. More elevated homocysteine in the depressive than in the healthy premenopausal women points to the notion that psychological factors might be important when considering the homocysteine concentration.

Ocular changes in pregnancy

Visual changes in pregnancy are common, and many are specifically associated with the pregnancy itself. Serous retinal detachments and blindness occur more frequently during preeclampsia and often subside postpartum. Pregnant women are at increased risk for the progression of preexisting proliferative diabetic retinopathy, and diabetic women should see an ophthalmologist before pregnancy or early in the first trimester. The results of refractive eye surgery before, during, or immediately after pregnancy are unpredictable, and refractive surgery should be postponed until there is a stable postpartum refraction. A decreased tolerance to contact lenses also is common during pregnancy; therefore, it is advisable to fit contact lenses postpartum. Furthermore, pregnancy is associated with a decreased intraocular pressure in healthy eyes, and the effects of glaucoma medications on the fetus and breast-fed infant are largely unknown.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to list the various ocular changes that occur during pregnancy, summarize the ocular disturbances that occur with preeclampsia and diabetes, and describe the management of some ocular problems during pregnancy.

National differences in lipid response to postmenopausal hormone replacement therapy

OBJECTIVE

To compare the response of serum lipids and lipoproteins to the transdermal hormone replacement therapy (HRT) in five European countries.

METHODS

Five-hundred and sixty-seven healthy postmenopausal women from Belgium, Finland, the Netherlands, Sweden, and the UK received transdermal estradiol 50 microg daily for 12 months. In addition, two groups received transdermally norethisterone acetate (NETA) continuously, two groups sequentially (170 or 350 microg/day); one group received sequentially oral NETA (1 mg/day), and one group dydrogestrone (20 mg/day). Serum total cholesterol, HDL-, HDL2-, LDL-cholesterol, lipoprotein(a) (Lp(a)), and triglycerides were assessed before and at the end of treatment.

RESULTS

No significant national differences existed in the pretreatment levels of lipids and lipoproteins. Mean cholesterol, LDL, Lp(a), and triglycerides decreased during HRT, and HDL and HDL2 increased. Individual changes in responses to HRT were strongly dependent on pretreatment values. In this regard, British women differed from the others: their cholesterol, HDL, HDL2, and Lp(a) responses, when related to the pretreatment levels, were smaller than those of the others.

CONCLUSION

A national difference discovered in response of serum lipids to HRT calls for caution in generalization of lipid data from one nation to another during HRT.

Pulsatile ocular blood flow during pregnancy

PURPOSE

To study pulsatile ocular blood flow (POBF) throughout pregnancy.

METHODS

We enrolled twenty-seven healthy women in the first trimester of gestation, only ten of which were followed through the second trimester, and fourteen non pregnant healthy women. In each subject we measured POBF with the POBF pneumotonometer (OBF Ltd. UK), IOP, blood pressure (BP) and heart rate (HR). An unpaired Student t-test was used to compare pregnant women with non-pregnant women, and a two-tailed paired Student t-test was used to compare the same women in the first and second trimester of pregnancy. p <0.05 is considered statistically significant.

RESULTS

Results are presented as means +/- SD. In the first trimester of pregnancy the age was 32 +/- 6, POBF 1516.4 +/- 382 ml/min, IOP 13 +/- 3 mmHg, BP 92 +/- 6 mmHg, and HR 86 +/- 14 beats/min. In the second trimester POBF was 1629.11 +/- 352.4 ml/min, intraocular pressure (IOP) 12 +/- 3 mmHg, BP 96 +/- 3 mmHg, and HR 93 +/- 10 beats/min. In the control group the age was 27 +/- 9, POBF 972.23 +/- 329.3 ml/min, BP 88 +/- 4.3 mmHg, and HR 80 +/- 14 beats/min. POBF increases during the first trimester (p = 0.00008). In the second trimester POBF was higher compared to the first trimester (p = 0.0008). Non significant differences were observed for the other parameters.

CONCLUSIONS

The POBF increases throughout gestation. During pregnancy there is an increase in estrogen which induces endothelial-dependent vasodilatation in several tissues. The estrogen changes may influence POBF.

Hyperhomocysteinaemia and cardiovascular risk in female ovariectomized rats: role of folic acid and hormone replacement therapy

Hyperhomocysteinaemia is an independent risk factor for arteriosclerosis, recurrent thromboembolic complications and osteoporosis. After menopause, a high level of total homocysteine seems to be secondary to the altered hormonal status. Hormone replacement therapy (HRT) limits the development of coronary artery disease through a variety of mechanisms. One such mechanism is through affecting homocysteine metabolism. Folate and vitamin B12 deficiencies are considered to be major risks for hyperhomocysteinaemia. This study, therefore, was undertaken to examine whether lowering homocysteine with HRT or folic acid in ovariectomized rats could attenuate cardiovascular complications. Sixty sexually mature female Wistar rats were ovariectomized. Three weeks later, they were treated with estradiol (15 microg kg(-1), every two weeks, i.m.) or folic acid (90 microg daily, orally), either alone or in a combined form for four weeks. In addition, groups of ovariectomized rats (positive control) and healthy rats (negative control) were given cottonseed oil. Blood samples were then collected for serum and plasma separation. Serum total homocysteine, folate, estradiol, plasma nitric oxide (NO), lipid profile, and susceptibility of non-high-density-lipoprotein cholesterol (non HDLC) content to oxidation were determined. In ovariectomized rats, hyperhomocysteinaemia was established and associated with significant increments of both atherogenic indexes (total cholesterol/HDLC, low-density-lipoprotein cholesterol (LDLC)/HDLC) and susceptibility of their non HDLC to oxidation. However, plasma NO, serum folate, and estradiol levels significantly decreased. HRT and folic acid significantly reduced total homocysteine and susceptibility of non HDLC to oxidation and increased plasma NO content. Moreover, a significant negative correlation was found between total homocysteine versus folate and estradiol (r = -0.5, P < 0.01; r = -0.25, P < 0.05, respectively). Meanwhile, a positive correlation with the susceptibility of lipoprotein to oxidation was observed (r = 0.85, P < 0.001). In conclusion, a low folate level is found to be associated with elevated total homocysteine. Folic acid supplementation, either individually or in a combined form with HRT, has a beneficial effect in low estrogen status subsequent to ovariectomy.

Effect of postmenopausal hormone replacement therapy on lipoprotein and homocysteine levels in Chinese women

Epidemiological studies have revealed that postmenopausal estrogen replacement therapy results in a marked reduction in the risk for cardiovascular diseases. In the present study, we evaluated plasma lipoprotein profile as well as homocysteine levels in 145 postmenopausal and premenopausal Chinese women living in Hong Kong. We also investigated the effect of hormone-replacement therapy (HRT) with estrogen or estrogen combined with progestin on plasma lipoprotein profile and homocysteine concentrations in those individuals. Postmenopausal women displayed significantly higher plasma levels of total cholesterol, LDL-cholesterol and apoB as well as higher plasma homocysteine levels than that of premenopausal women. HRT with either estrogen (17beta-estradiol or conjugated equine estrogen) alone or estrogen combined with progestin for 3.5-4.5 years significantly improved the lipoprotein profile in postmenopausal women by decreasing the levels of total cholesterol (12-20% reduction), LDL-cholesterol (26-29% reduction) and apoB (21-25% reduction). In women treated with 17beta-estradiol or conjugated equine estrogens their plasma levels of apoAl were significantly elevated (18% elevation) as compared to non-users. HRT also reduced plasma concentrations of homocysteine (13-15% reduction). In conclusion, we found that long-term HRT was associated with improvement in plasma lipoprotein profile and a reduction in homocysteine concentration in postmenopausal women. These results support the notion that the improvement of lipoprotein profile and a reduction in homocysteine concentration may contribute to the beneficial effect of HRT on cardiovascular risk.

Specific inhibition of estrogen receptor alpha function by antisense oligodeoxyribonucleotides

We have tested the effect of a range of antisense oligodeoxyribonucleotides (ODN) directed against the human estrogen receptor alpha (ERalpha) on ERalpha protein expression and function. Antisense ERalpha ODN transfected into the ERalpha-positive human breast carcinoma cell line MCF7-K2 showed variable responses dependent on the oligo used. The most active antisense ODN (oligo 7) decreased the levels of ERa protein by 61% as measured by Western blot analysis. Exogenous 17beta-estradiol (17beta-E2), but not 17alpha-E2, augmented this effect, with a threshold effect at 10(-8) M 17beta-E2. The inhibitory effect of antisense ERa oligo 7 was confirmed by measurement of functional ERalpha protein. 3H-17beta-E2 binding to MCF7 cell extracts was inhibited to approximately 40% of control values in the presence of oligo 7. Antisense-transfected MCF7-K2 cell cultures produced a further 30% binding reduction in the presence of exogenous 17beta-E2. An inhibitory effect on 17beta-E2-dependent cell function was confirmed by the demonstration that ERalpha oligo 7-transfected MCF7-K2 cells failed to exhibit 17beta-E2-stimulated cell proliferation. Exogenous 17beta-E2 enhanced the inhibitory effect of the antisense ODN by increasing ODN transfection efficiency but without ERalpha catabolism via the proteosomal pathway, suggesting an effect of 17beta-E2 on the plasma membrane and the existence of different ERalpha degradation pathways in the MCF7-K2 cell subclone. As 17beta-E2 had no effect on ERalpha protein degradation, we conclude that the observed reduction of ERalpha protein levels is due solely to the presence of the antisense ERalpha ODN. Antisense ERalpha ODN molecules, therefore, may form the basis of effective therapies against ERalpha-dependent malignancies.

Continuous combined hormone replacement therapy with oral 17beta-estradiol and norethisterone acetate improves homocysteine metabolism in postmenopausal women

OBJECTIVE

To evaluate the effect of a continuous combined oral hormone replacement therapy (HRT) on basal and post-methionine load homocysteine levels in postmenopausal women.

DESIGN

Twenty-two postmenopausal women (PMW) were randomly allocated to receive either continuous combined oral HRT (2 mg of estradiol plus 1 mg of norethisterone acetate; n = 11) or no treatment (controls, n = 11) for 6 months. A methionine oral load (0.1 g/kg body weight) was performed in each subject at time 0 and after 6 months. Serum homocysteine levels were measured by high-performance liquid chromatography in samples collected at time 0 and at 4, 8, and 24 h after the methionine load, while levels of vitamin B6 (by high-performance liquid chromatography) and B12 and folate (both by ELISA) were assayed in samples collected at time 0.

RESULTS

Serum levels of glucose and body mass index increased in treated PMW, whereas folate decreased in controls. In treated PMW, basal homocysteine tended to decrease (10.6 +/- 3.3 micromol/L vs. 9.62 +/- 2.8 micromol/L, p = 0.062), whereas in controls it significantly increased (10.7 +/- 2.65 micromol/L vs. 12.17 +/- 3.89 micromol/L, p < 0.05). This increase was not significant after correction for vitamin status (p = 0.072). Homocysteine values 4 h (31.9 +/- 13.53 micromol/L vs. 39.83 +/- 22.53 micromol/L, p < 0.05) and 8 h (35.1 +/- 13.13 vs. 43.34 +/- 22.15 micromol/L) after methionine, and integrated homocysteine response to methionine (392.5 +/- 133.8 micromol/24 h vs. 458.8 +/- 104.8 micromol/24 h; p < 0.05), were significantly reduced in HRT-treated, but not in untreated, PMW.

CONCLUSIONS

Continuous combined oral HRT with17beta-estradiol plus norethisterone acetate reduces homocysteine levels, mainly after a methionine load. This effect seems to be independent of vitamin status and may have positive implications for the prevention of cardiovascular diseases in PMW.

Connexin 43 expression in rat aortic smooth muscle after ovariectomy and hormonal replacement

The purpose of this study was to determine the effects of ovariectomy and long-term combined sexual hormone replacement on the gap junctional protein, connexin 43 (Cx43) of aortic medial smooth muscle cells in rats. Twenty non-pregnant mature Wistar female rats were divided into five groups (four animals in each group). Group A underwent ovariectomy, Group B underwent ovariectomy and received estradiol propionate, Group C underwent ovariectomy and received medroxyprogesterone acetate and Group D underwent ovariectomy and received both hormones. Group E was sham-operated and used as control. After 15 weeks of treatment, thoracic aortas were removed and immunohistochemistry was carried out using a specific fluorescent antibody against Cx43. Tissue sections were examined by confocal laser scanning microscopy and analysed by the Scion Image program. All five different groups had the same distribution and extent of Cx43 in the aorta. Neither the ovariectomy nor the hormone replacement had any effect on the Cx43 expression of aortic smooth muscle cells in rats as compared to control animals. These results indicate that sexual steroids do not influence the gap junctional protein Cx43 of the medial layer of aorta in rats. They may suggest that the beneficial effects of estrogen are not mediated via gap junctions in the human aorta either.

Perspectives in hormone replacement therapy

Estrogens have been convincingly shown to be highly effective in preventing and reversing menopause-related conditions, such as hot flushes, urogenital complaints, and postmenopausal bone loss. Observational studies report that long-term, estrogen-containing, postmenopausal hormone replacement therapy (HRT) leads to a substantial reduction in hip fractures, myocardial infarction, and possibly colonic cancer, with important consequences for health and quality of life. Estrogen replacement may postpone the onset of Alzheimer's disease and extend life. While many of these effects are biologically plausible, with a variety of cellular mechanisms being involved, only ongoing and future large-scale randomized clinical trials can and should define the effects of HRT more precisely. Long-term compliance is a key issue for long-term benefits, and offering women a choice of administration routes and regimens can only be beneficial in this respect. Pills, patches, gels, and implants are all widely prescribed. Intravaginal or intranasal forms of administration, which are very easy to use and adaptable on an individual level, are among the new options which could improve long-term continuation of HRT use. Fear of breast cancer and recurrence of vaginal bleeding are real concerns for many women considering HRT. This has led to research into lower-dose, estrogen-containing regimens, into continuous combined regimens, and into the potential of estrogen receptor alpha or beta binding molecules that may help to prevent such problems from arising. The prospects for safe and effective postmenopausal HRT with either estrogens or estrogen-like drugs are very promising when these drugs are used in a patient-tailored, risk profile-based manner.

Sex hormone replacement therapy reverses decreased venous distensibility in pharmacologically ovariectomized rats

OBJECTIVE

To test the effect of female sex hormone depletion and replacement on the distensibility and geometry of the saphenous vein in female rats.

DESIGN

Twenty Sprague-Dawley rats were pharmacologically ovariectomized by triptorelin. Ten of these animals received combined hormone replacement with estradiol and medroxyprogesterone acetate. The rest were given vehicle. Ten animals kept parallel without pharmacological ovariectomy served as controls. After 3 months of treatment, a segment of the saphenous vein was dissected. Pressure-diameter curves were recorded in relaxed, contracted, and control states using a microangiograph.

RESULTS

Pharmacological ovariectomy lowered venous wall distensibility measured in contraction (at P=8 mm Hg: 4.41+/-1.21*10(-3) m2/N vs. control: 0.79+/-0.14*10(-3) m2/N; p < 0.05). Hormone replacement partially restored this value (1.8+/-0.49*10(-3) m2/N). No alterations in distensibility were found in the relaxed state. After adjusting for body weight, we found that pharmacological ovariectomy lowered venous inner radius significantly compared with control (p < 0.05), whereas hormone replacement increased it compared with pharmacological ovariectomy (p < 0.05) and more significantly compared with control (p < 0.01).

CONCLUSION

Sex hormone depletion induces significant alterations in venous distensibility, presumably by inducing initial remodeling of the venous wall. Hormone dependency of distensibility differed in relaxed and contracted states of the vein, so some alterations of contractile elements of the wall may be hypothesized. Lower distensibility of the venous wall found after pharmacological ovariectomy could be part of the mechanism of predisposition for postmenopausal hypertension. This can be reversed by female sex hormone replacement.

Effect of medroxyprogesterone acetate and norethisterone on serum-stimulated and estradiol-inhibited proliferation of human coronary artery smooth muscle cells

OBJECTIVE

The addition of progestogen to estrogen replacement therapy is thought to antagonize, at least in part, the beneficial effects of estrogens on the vasculature. The aim of this study was to investigate the effect of two progestogens mostly used in clinical practice on the proliferation of vascular smooth muscle cells, which has been demonstrated to be a crucial step in the development of atherosclerosis.

MATERIAL AND METHODS

The effect of medroxyprogesterone acetate (MPA) and norethisterone (NET), which represent the two different classes of C21- and C19-progestogens, respectively, was investigated on proliferation of smooth muscle cells from human coronary artery in vitro. The steroids were tested in the concentration range 10(-8) to 10(-5) M, which is in the upper range of that reached during hormonal replacement therapy, and compared with control values.

RESULTS

Estradiol significantly inhibited serum-stimulated cell growth at the concentrations 10(-6) and 10(-5) M by 18% and 34%, respectively. MPA significantly enhanced serum-stimulated growth at the concentrations 10(-6) and 10(-5) M by 29% and 47%, respectively. In equimolar combinations of MPA and estradiol, proliferation of the cells was significantly stimulated at the concentrations 10(-6) and 10(-5) M by 26% and 44%, respectively. In contrast, NET had no significant effect on serum-stimulated cell growth and had no impact on the estradiol-inhibited proliferation.

CONCLUSIONS

These data suggest that MPA may antagonize beneficial antiatherosclerotic estradiol effects on the vasculature, whereas NET may be neutral in this respect. However, these effects occurred at supraphysiological concentrations. Because these concentrations might be reached in the target tissues, the clinical relevance for treatment of patients with cardiovascular risk cannot be excluded.

Lipoprotein (a) is associated with endothelial function in healthy postmenopausal women

BACKGROUND

Lipoprotein (a) (Lp(a)) is an independent risk factor for atherosclerotic cardiovascular disease. The atherogenic potential of Lp(a) may be by impairment of endothelial function. Objectives. We investigated the relation of Lp(a) plasma levels to endothelium dependent and independent dilatation of the brachial artery in healthy postmenopausal women.

METHODS

One hundred and five healthy postmenopausal women aged 52-67 years were included in the study. Endothelial function was assessed non-invasively by measuring percent lumen diameter change in the brachial artery after reactive hyperemia and sublingual nitroglycerine spray.

RESULTS

Flow mediated dilatation was inversely related to the plasma logLp(a) level. Mean change per unit logLp(a) increase:-2.83% (95% CI: -5.22--0.43). Elevated Lp(a) (>239 mg/l) (upper quartile) was associated with an impaired flow mediated vasodilatation (2.4%+/-1. 2) compared to Lp(a) < or =239 mg/l (5.2%+/-0.7). Adjustment for other cardiovascular risk factors did not change the magnitude of the association. Nitroglycerine-induced vasodilatation was not significantly lower in the high Lp(a) level group, compared to the group with normal levels of Lp(a) (< or =239 mg/l) (8.0+/-1.2 vs. 11.4%+/-0.8).

CONCLUSION

Elevated lipoprotein (a) levels are associated with an impaired endothelial function in healthy postmenopausal women, independent of conventional risk factors for cardiovascular disease. Since Lp(a) may be pathogenetically important for early vascular damage, elevated Lp(a) levels might contribute to the increased cardiovascular risk seen in postmenopausal women.