Postmenopausal hypertension

Diseases and Aging: Gender Matters

At first glance, biological differences between male and female sex seem obvious, but, in fact, they affect a vast number of deeper levels apart from reproductive function and related physiological features. Such differences affect all organizational levels including features of cell physiology and even functioning of separate organelles, which, among other things, account for such global processes as resistance to diseases and aging. Understanding of mechanisms underlying resistance of one of the sexes to pathological processes and aging will allow taking into consideration gender differences while developing drugs and therapeutic approaches, and it will provide an opportunity to reproduce and enhance such resistance in the more vulnerable gender. Here we review physiological as well as cellular and biological features of disease course including aging that are affected by gender and discuss potential mechanisms behind these processes. Such mechanisms include features of oxidative metabolism and mitochondrial functioning.

Blood pressure in the Congolese adult population of South Kivu, Democratic Republic of Congo: Preliminary results from the Bukavu Observ Cohort Study

BACKGROUND

Providing factual data about non-communicable diseases (NCDs) is of utmost importance in the sub-Saharan African countries where NCDs and arterial hypertension data remain scattered, scarce, and less representative given the region's heterogeneous population. Within this context, the interuniversity cooperation VLIR-UOS/Catholic University of Bukavu (Democratic Republic of Congo) has established an integrated project for monitoring hypertension and cardiovascular risk factors in the population of South Kivu. The aim of the study was to present the basic results of the determinants of blood pressure in the cohort studied.

METHODS

In 2013 and 2014, trained interviewers collected the anthropometric parameters, blood pressure, and medical history of 7405 adults (3060 in urban areas and 4345 in rural areas) including 3162 males and 4243 females; the cohort is expected to be followed for 9 years.

RESULTS

The average age of the entire group was 33.0±16.7 years. Compared to men, women had significantly higher obesity indices (P<0.0001), lower blood pressure between 20 and 39 years of age (P<0.0001) but higher blood pressure at 60 years of age and older (P<0.0001). Blood pressure was positively correlated with body mass index, waist circumference, and paradoxically with consumption of vegetables, but negatively correlated with the consumption of fruit, intense physical activity, and relaxation at home.

CONCLUSIONS

These results show that a cohort study is feasible in the Democratic Republic of Congo. The factual data analysis can contribute to health policy orientation and setting up of preventive measures. Since most correlated risk factors are preventable, recommendations can already be made in the fight against high blood pressure in this population.

Antihypertensive drug prescription patterns, rationality, and adherence to Joint National Committee-7 hypertension treatment guidelines among Indian postmenopausal women

Aim of Study:

The aim of this study is to evaluate antihypertensive drug prescription patterns, rationality and adherence to Joint National Committee (JNC-7) hypertension (HT) treatment recommendations among Indian postmenopausal women (PMW).

Materials and Methods:

An observational and cross-sectional prospective prescription audit study was carried over a period of 1 year. A total of 500 prescriptions prescribed to PMW for diagnosed HT, were identified for one point analysis. Drug prescription patterns/trends, and their adherence to JNC-7 report as well as rationality using WHO guide to good prescribing was assessed.

Results:

In the monotherapy, category angiotensin receptor blockers (ARBs) accounted (24.8%), calcium channel blockers (CCBs) (19.4%), angiotensin converting enzyme inhibitors (ACEIs) (11%), beta blockers (BBs) (2.8%), and diuretics (2%) of the total prescription. Individually, amlodipine was maximally prescribed in 16.4%. 31.6% had double combination, whereas 2.2% and 1% had triple and four drug combinations, respectively. About 3.6% of the prescription contained antihypertensive combination along with other class of drug. ARBs + diuretic were observed in 11%, CCBs + BB 10% and ACEI + diuretic in 2.6% of the total prescriptions. Among the combination therapy amlodipine + atenolol (8.4%), telmisartan + hydrochlorothiazide (6%) and losartan + hydrochlorothiazide (4.4%) were maximally prescribed. 84.21% (P < 0.001) of the prescription showed nonadherence as per recommendations for pre-HT. 100% and 43.25% adherence rates were noticed for Stage 1 HT (P < 0.001) and Stage 2 HT (P > 0.05) patients.

Conclusion:

Antihypertensive prescription trends largely adhere to existing guidelines and are rational except polypharmacy, generic and fixed dose combinations prescribing, were some of the common pharmacologically considered irrationality noticed.

Endocrinology of menopause

Menopause is a natural process that occurs in women's lives as part of normal aging. Many women go through the menopausal transition with few or no symptoms, while some have significant, or even disabling, symptoms. This manuscript reviews the physiologic processes and symptoms connected with menopause and the diseases associated with menopause, as well as how menopausal symptoms are managed.

Does metabolic syndrome or its components differ in naturally and surgically menopausal women?

OBJECTIVES

This study aimed to compare metabolic syndrome and its components in naturally and surgically menopausal women.

METHODS

This is a longitudinal study, with incident case and control groups, conducted on 446 women participants of the Tehran Lipid and Glucose Study, who experienced surgical or natural menopause over a 10-year period. In both groups, data collection was conducted using questionnaires including information on demographic, reproductive and metabolic characteristics at baseline and again after 3 years. Physical examinations and the biochemical profiles were also assessed.

RESULTS

During the follow-up, metabolic syndrome was observed in 28.7% and 32.5% of the naturally menopause and surgically menopausal women, respectively. Mean fasting blood sugar and 2-h plasma glucose were significantly higher in the surgically menopause group, compared to the naturally menopause one, whereas mean systolic blood pressure was significantly higher in naturally menopausal women as compared to surgically menopause ones, after further adjustment for premenopausal status.

CONCLUSIONS

Although no difference in the prevalence of metabolic syndrome in naturally menopausal women and in surgically menopausal women was found, the components of metabolic syndrome were more prevalent among those with surgical menopause.

Prevalence of cardiovascular risk factors in postmenopausal women: A rural study

Aim:

The present observational, cross-sectional prospective study was conducted during the period of 1 year in one of the rural health centers to study prevalence of conventional cardiovascular disease risk factors (CVRFs) in postmenopausal women.

Materials and Methods:

Five hundred consecutive postmenopausal women were screened for detailed information regarding common menopausal symptoms, the presence or absence of conventional CVRFs. Physical activity was measured, and dietary lifestyle was also assessed. Use of hormone replacement therapy (HRT) and other drugs were also noted. Knowledge regarding their menopause was also evaluated.

Results:

Mean age at menopause was 49.35 years, Mean number of menopausal symptoms was 6.70 ± 5.76, and mean duration since menopause was (MDSM = 4.70 years)). Fatigue, lack of energy (70%), cold hand and feet, rheumatology-related symptoms (60%) cold sweats, weight gain, irritability, and nervousness (50%), palpitation of heart, excitable/anxiety (30%) each were common complaints. Hypertension was diagnosed or a person was a known hypertensive (56%). Diabetes was diagnosed or a person was known diabetic in 21%, and BMI was found to be 25 kg/m² in 78%. Truncal obesity with waist-hip ratio >0.8 in 68% females, whereas abdominal obesity with waist size >88 cm was in 60% women. Dyslipidemia was seen in 39%. It was defined by the presence of high TC (=200 mg/dL) in 30%, high LDL-c (=130 mg/dL) in 27%, low HDLc (<40 mg/dL) in 21% or high TG (=150 mg/dL) in 31%. Metabolic syndrome was present in 13% of cases. CRP was found positive in 12 out of 39 total evaluated women, and serum uric acid was found >6.5 mg/dL in 4%. Smoking (0.5%), alcohol (0%,), tobacco chewing (4%), and family history of premature heart disease (9%) were recorded. Lifestyle was active in 35%, hectic in 10%, and sedentary in 55% of postmenopausal women (PMWs). Only 5% of women were receiving HRT, 0.5% isoflavone-containing phytoestrogens, 0.4% tibolone, 24% anti-HT, 9% anti-diabetic, 8% lipid-lowering drugs, and only three patients were on anti-obesity along with dietary and lifestyle management. Out of 68 patients, who were advised for electrocardiography (ECG), 23 were found positive for ischemic changes on ECG and out of 12 women advised for treadmill test (TMT), only four were found positive for ischemic heart disease (IHD). Risk factor count of more than four was found in 11%. Over all 96% of women were affected by menopause or related problems. Only 9% were aware about their menopause, 3% for importance of lifestyle modification, weight and dietary management programs to ameliorate menopause or menopause-compounded CVRFs.

Conclusion:

This study showed alarmingly high prevalence of most of the conventional CVRFs, especially diabetes, hypertension, dyslipidemia, obesity, and other risk factors in postmenopausal women from rural areas.

Stimulation of cardiac apoptosis in ovariectomized hypertensive rats: potential role of the renin-angiotensin system

OBJECTIVES

The mechanisms underlying the increased cardiovascular risk after menopause are poorly understood. Estrogens modulate the cardiac renin-angiotensin system (RAS) and influence cardiac adaptation to afterload. To investigate whether the loss of the natural inhibition of the RAS by estrogen may be linked to an increase of cardiac apoptosis, we studied 17β-estradiol (E2) and/or angiotensin-converting enzyme (ACE) inhibitor treatment effects on cardiomyocyte survival in ovariectomized spontaneously hypertensive rats (SHRs).

METHODS

Five groups of female SHRs were evaluated for 8 weeks. One group served as nonovariectomized control; the other four groups underwent bilateral ovariectomy and were randomized to receive 60-day-release pellets containing placebo or 0.5 mg of E2, the ACE inhibitor ramipril at the dosage of 2.5 mg/kg per day, or the combination of the two treatments.

RESULTS

Ovariectomy increased cardiomyocyte apoptosis and induced proapoptotic changes of Bcl-2 and Bax genes and proteins. These modifications were associated with an upregulation of ACE and angiotensin II type 1 (AT1) receptor genes. Ramipril was as effective as E2 in preventing cardiac apoptosis and in restoring cardiac brain natriuretic peptide in association with reduced cardiac ACE and AT1 receptor gene expression. In contrast to the ramipril treatment, the favorable effect of E2 on cardiac apoptosis occurred independently from changes in SBP. No synergistic effect was observed when the two treatments were combined.

CONCLUSION

These data show that ovariectomy stimulates myocardium apoptosis by a mechanism involving Bax and Bcl-2 genes. The antiapoptotic effect of E2 and ACE inhibitor treatment was linked to a downregulation of cardiac RAS.

Effect of 6-months of physical exercise on the nitrate/nitrite levels in hypertensive postmenopausal women

Background

Evidences have showed that the incidence of arterial hypertension is greater in postmenopausal women as compared to premenopausal. Physical inactivity has been implicated as a major contributor to weight gain and abdominal obesity in postmenopausal women and the incidence of cardiovascular disease increases dramatically after menopause. Additionally, more women than men die each year of coronary heart disease and are twice as likely as men to die within the first year after a heart attack. A healthy lifestyle has been strongly associated with the regular physical activity and evidences have shown that physically active subjects have more longevity with reduction of morbidity and mortality. Nitric oxide (NO) produced by endothelial cells has been implicated in this beneficial effect with improvement of vascular relaxing and reduction in blood pressure in both laboratory animals and human. Although the effect of exercise training in the human cardiovascular system has been largely studied, the majority of these studies were predominantly conducted in men or young volunteers. Therefore, the aim of this work was to investigate the effects of 6 months of dynamic exercise training (ET) on blood pressure and plasma nitrate/nitrite concentration (NOx^-) in hypertensive postmenopausal women.

Methods

Eleven volunteers were submitted to the ET consisting in 3 days a week, each session of 60 minutes during 6 months at moderate intensity (50% of heart rate reserve). Anthropometric parameters, blood pressure, NOx^- concentration were measured at initial time and after ET.

Results

A significant reduction in both systolic and diastolic blood pressure values was seen after ET which was accompanied by markedly increase of NOx^- levels (basal: 10 ± 0.9; ET: 16 ± 2 μM). Total cholesterol was significantly reduced (basal: 220 ± 38 and ET: 178 ± 22 mg/dl), whereas triglycerides levels were not modified after ET (basal: 141 ± 89 and ET: 147 ± 8 mg/dl).

Conclusion

Our study shows that changing in lifestyle promotes reduction of arterial pressure which was accompanied by increase in nitrite/nitrate concentration. Therefore, 6-months of exercise training are an important approach in management arterial hypertension and play a protective effect in postmenopausal women.

Renin-angiotensin system polymorphisms and risk of hypertension: influence of environmental factors

Renin-angiotensin system (RAS) polymorphisms have been studied as candidate risk factors for hypertension with inconsistent results, possibly due to heterogeneity among various environmental factors. We analyzed the association between RAS candidate gene polymorphisms and risk of hypertension among 2722 women and also explored whether these associations varied according to menopausal status, body mass index, and dietary factors. In a main-effects analysis of all 2722 women adjusted for age and race, homozygosity for the AT1R A1166C polymorphism was associated with hypertension (odds ratio, 1.35; 95% confidence interval [CI], 1.03-1.78). We also found that a novel nonsense polymorphism in the aminopeptidase-A gene was associated with hypertension among postmenopausal women (hazard ratio, 1.54; 95% CI, 1.01-2.37), women with inadequate calcium intake (hazard ratio, 2.47; 95% CI, 1.29-4.72) and, marginally, women with inadequate vitamin D intake. In addition, angiotensin-converting enzyme and AT1R A1166C polymorphisms were associated or marginally associated with incident hypertension among postmenopausal women and those with inadequate calcium and vitamin D intakes. These data suggest that demographic and dietary factors may influence the associations between RAS polymorphisms and hypertension and could explain heterogeneity in prior studies.

Bilateral oophorectomy before 50 years of age is significantly associated with the metabolic syndrome and Framingham risk score: a controlled, population-based study (HUNT-2)

OBJECTIVE

Bilateral oophorectomy (BOE) is often recommended in order to prevent cancer at hysterectomy for non-malignant diseases and when familial risk of ovarian and breast cancer has been identified. Surgical menopause increases the risk of cardiovascular mortality, however, the intervening mechanisms are not clear. We compared the prevalence of the metabolic syndrome (MetS) and Framingham cardiovascular risk scores in women with BOE before 50 years of age to age-matched controls in a population-based study.

METHODS

20,765 women aged 40-69 years were invited to a health study (HUNT-2 Norway 1995-97) and 17,650 (85%) attended. We compared 263 women with BOE before 50 years of age [63 with intact uterus (BO1 group), and 200 with hysterectomy also (BO2 group)] with 3 age-matched controls per case (n=789). Data on demographic, somatic, mental, and lifestyle variables, physical measurements and blood tests were obtained.

RESULTS

The BO1 and BO2 groups did not differ significantly regarding risk variables, and 4% had natural menopause. The combined BOE group had increased prevalence of MetS compared to controls according to the International Diabetes Federation's definition (47% versus 36%; p=.001) and the revised NCEP ATP III definition (35% versus 25%; p=.002), which remained after adjustments (for reproductive, global health, and lifestyle variables). The prevalence of Framingham risk score > or =10% was higher in cases (22%) versus controls (15%) p=.005.

CONCLUSION

The higher prevalence of MetS and increased Framingham risk scores in women with bilateral oophorectomy before 50 years of age suggests that these women may be at higher risk of type 2 diabetes and cardiovascular disease compared to their counterparts in the general population.

Upregulation of adipose 11-beta-hydroxysteroid dehydrogenase type 1 expression in ovariectomized rats is due to obesity rather than lack of estrogen

OBJECTIVE

Increased tissue activity of cortisol induced by the activation of inert cortisone to active cortisol through 11-beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) may play a role in the metabolic syndrome. We recently found that 11beta-HSD1 in subcutaneous adipose tissue (AT) was lower in lean women compared with lean men. Estrogen suppresses hepatic and renal 11beta-HSD1 in rats; hence we investigated the in vitro effect of estrogen on human and rat AT, and the in vivo effects on rat AT 11beta-HSD1 expression.

METHODS AND PROCEDURES

Wistar rats were divided into four groups of eight animals. One group was sham-operated (controls) and others were ovariectomized (OVX). One OVX group was left untreated (OVX-E), another (OVX+E) received estrogen treatment, and one received a hypo-caloric diet (OVX-E+D), matching the weight gain of the control group. AT from women undergoing liposuction or surgery and from killed male and female rats were incubated with estrogen alone or in the presence of IL-1beta. Gene expressions were determined by real-time reverse transcriptase PCR.

RESULTS

Ovariectomy resulted in a 280% increase in adipose 11beta-HSD1 expression P < 0.05). 11beta-HSD1 expression in the (OVX+E)-group was significantly reduced compared with the nonsubstituted group (P < 0.05). 11beta-HSD1 expression in the (OVX-E+D)-group was reduced significantly (P < 0.05) when compared with the level of the estrogen-substituted group. No significant differences between the control group, the (OVX+E)-group, and the (OVX-E+D)-group were found. In the in vitro studies, no direct effect of estrogen on adipose 11beta-HSD1 was found.

DISCUSSION

The upregulation of 11beta-HSD1 in ovariectomized rats was most likely due to changes in body composition rather than lack of estrogen.

Effects of blood pressure reduction on cardiovascular risk estimates in hypertensive postmenopausal women

Menopause is accompanied by an increased prevalence of hypertension, which may partially explain the corresponding cardiovascular risk observed in postmenopausal women. The relationship between blood pressure and cardiovascular risk is continuous, consistent and independent of other risk factors. There are profound benefits of treating hypertension: antihypertensive therapy has been associated with large reductions in stroke, myocardial infarction and heart failure. Despite these proven benefits, hypertension is inadequately treated, or not treated at all, in the majority of patients. There has been concern regarding the use of hormone therapy in hypertensive postmenopausal women. Drospirenone/17beta-estradiol, a hormone therapy, has been demonstrated to lower blood pressure in hypertensive postmenopausal women either alone or when administered simultaneously with antihypertensive drugs. This might offer a potential advantage in patients with elevated blood pressure. It is also known that the risk for target organ events extends to levels well below the established definition of 140/90 mmHg. High-normal blood pressure carries an increased cardiovascular risk when compared to lower levels of blood pressure. Identification and management of elevated blood pressure are an important component of the successful management of the postmenopausal woman and can help prevent the untoward consequences of elevated blood pressure.

Oestrogen affects the cardiovascular and central responses to isoproterenol of female rats

This study examined the influence of oestrogen on cardiovascular responses to hypotension produced by administration of isoproterenol (Isop) and on neural activation in hindbrain nuclei mediating these responses. We first measured mean arterial pressure (MAP) and heart rate (HR) after administration of isoproterenol, a beta-adrenergic agonist that increases circulating levels of AngII, in ovariectomized (OVX) rats treated with oestradiol benzoate (EB). We then evaluated EB effects on Isop-induced Fos immunoreactivity (Fos-IR) in the hindbrain baroreflex circuit. To control for weight loss associated with oestrogen replacement in OVX rats, we food restricted a separate group of OVX rats and evaluated Isop-induced changes in MAP, HR and Fos-IR. The depressor response to Isop was significantly attenuated by EB, which also produced a disproportionate increase in HR. These effects were not secondary to loss of body weight after EB treatment, because cardiovascular responses to Isop in food restricted rats were similar to those in OVX rats treated with the oil vehicle. Isop significantly increased Fos-IR in the nucleus of the solitary tract (NTS), area postrema (AP), rostral ventrolateral medulla (RVLM), and lateral parabrachial nucleus (lPBN); however, EB significantly attenuated the increase in the AP and in the lPBN. Again, these effects were not secondary to body weight loss, because food restricted rats had the same pattern of Fos-IR as did rats treated with the oil vehicle. These results suggest that EB modifies cardiovascular responses to Isop, possibly by decreasing activation of the AP and lPBN.

Low sex hormone-binding globulin is associated with the metabolic syndrome in postmenopausal women

Although an association between the metabolic syndrome and hyperandrogenism has been suggested in women with polycystic ovarian syndrome, few studies have investigated this relationship in postmenopausal women. We measured estradiol, testosterone, and sex hormone-binding globulin (SHBG) and calculated the free androgen index (FAI) in 212 postmenopausal women not using hormone therapy in the Women's Health Study. A modified definition of the metabolic syndrome (3 or more of the following: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein, elevated blood pressure, and abnormal glucose metabolism) from the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults was used. Women with the metabolic syndrome had higher mean levels of estradiol, testosterone, and FAI values and lower SHBG levels. Higher FAI and lower SHBG were associated with all components of the metabolic syndrome. After adjustment for BMI and other factors, women in the highest tertile of FAI had an odds ratio of 12.6 (95% confidence interval, 3.8-41.6) for the metabolic syndrome, whereas those in the lowest SHBG tertile had an odds ratio of 7.3 (95% confidence interval, 2.7-19.8). When stratified by body mass index, the associations with high FAI and low SHBG remained significant even in women with body mass index less than 26.7 kg/m2. An androgenic hormone profile is associated with both the individual components of the metabolic syndrome and clustering of metabolic abnormalities in postmenopausal women.

Salt sensitivity and hypertension after menopause: role of nitric oxide and angiotensin II

Hypertension is a major risk factor for cardiovascular disease and renal disease. After menopause, the incidence of hypertension increases in women to levels that equal or exceed that in men, suggesting a protective role of female sex hormones. Salt sensitivity of blood pressure is associated with an increased risk for development of hypertension and cardiovascular disease. We and others have demonstrated that after menopause, the prevalence of salt sensitivity increases, suggesting that female sex hormones influence renal sodium handling and blood pressure regulation. A homeostatic balance between the counteracting effects of nitric oxide (NO) and angiotensin (Ang) II on pressure natriuresis, renal hemodynamics, tubular sodium reabsorption, and oxidative stress plays an important role in modulating salt sensitivity as well as hypertensive end-organ injury. Estrogens modulate the activity and expression of NO and Ang II. We infer that after menopause, estrogen deficiency promotes an unbalance between NO and Ang II, resulting in disturbed renal sodium handling, oxidative stress, and hypertension, particularly in genetically prone women. A better understanding of the mechanisms underlying the development of postmenopausal hypertension and associated cardiovascular and renal diseases should provide insights into preventive and therapeutic strategies.

The metabolic syndrome in women: a growing problem for cardiac risk

The risk of developing cardiovascular disease has recently been associated with a set of metabolic and physiological risk factors that include abdominal obesity, atherogenic dyslipidemia, hypertension, and elevated plasma glucose. The term most commonly used to describe this conglomeration of risk factors is the metabolic syndrome. Coronary heart disease risk is tripled in those individuals with this syndrome. Primary treatment focuses on weight reduction and physical activity to reduce risk factors and prevent the progression to cardiovascular disease. This article will review the definition, prevalence, pathogenesis, and treatment of the metabolic syndrome in women and will discuss the role of polycystic ovarian syndrome in relation to the metabolic syndrome.

Variation in estrogen-related genes and cross-sectional and longitudinal blood pressure in the Framingham Heart Study

OBJECTIVE

To examine the association between variation in estrogen-related genes and cross-sectional and longitudinal blood pressure in men and women.

DESIGN

In 1780 unrelated members of the community-based Framingham Heart Study offspring cohort, systolic blood pressure and diastolic blood pressure were measured over a total of six examination cycles encompassing 24 years of follow-up. Multivariate regression analyses were used to assess the relation between untreated cross-sectional and longitudinal blood pressure and polymorphisms at the estrogen receptor-alpha (ESR1), estrogen receptor-beta (ESR2), aromatase (CYP19A1), and nuclear receptor coactivator 1 (NCOA1) genes after adjustment for common risk factors.

RESULTS

In men, systolic blood pressure and pulse pressure (systolic blood pressure minus diastolic blood pressure) were associated with two polymorphisms in ESR1, while pulse pressure was also associated with variations in NCOA1 and CYP19A1. Polymorphisms in ESR1, CYP19A1, and NCOA1 were associated with diastolic blood pressure in women.

CONCLUSIONS

Although the underlying relations between genes involved in estrogen action and hypertension remain to be completely understood, our findings provide suggestive evidence of gender-specific contributions of estrogen-related genes to blood pressure variation. As no correction for multiple testing was performed in the analyses, we view these results as suggestive and not definitive. Further studies are warranted to confirm these results using a comprehensive set of polymorphisms in order to shed more light on the involvement of estrogen in blood pressure regulation.

Alterations in aortic vascular reactivity to angiotensin 1–7 in 17-β-estradiol-treated female SD rats

Estrogen's suggested cardio-protective effects have come into question following the results of recent clinical trials. Two major components of the renin-angiotensin system (RAS) that are modulated by estrogen are angiotensin converting enzyme, and the angiotensin II type 1 receptor. Further research has revealed several new components of the RAS, including angiotensin converting enzyme 2, its peptide product angiotensin 1-7 (Ang 1-7), and that peptide's receptor, Mas. These components appear to oppose the classical effects of the RAS, and may act to buffer the RAS in vivo. Recent work has shown that during pregnancy, when estradiol levels are elevated, renal and urinary Ang 1-7 are greatly increased. This study examined the effects of estradiol on the efficacy of Ang 1-7 in the rat aorta. Female Sprague-Dawley rats were ovariectomized and a subgroup was chronically treated with subcutaneous pellets of estradiol for 3 weeks. Thoracic aortas were harvested for assessment of in vitro vascular reactivity to Ang 1-7. The results demonstrated that increased estradiol exposure attenuated the relaxation response to Ang 1-7 in a dose-dependent manner. These findings are in contrast to recent work showing potentiated responses to Ang 1-7 in mesenteric arteries from estrogen-manipulated rats, and may suggest a regional specificity in estradiol-mediated changes in the RAS.

Effects of oestrogen treatment and angiotensin-converting enzyme inhibition on the microvasculature of ovariectomized spontaneously hypertensive rats

We investigated the role of oestrogen in the function and structure of the microcirculation of female spontaneously hypertensive rats (SHRs), and evaluated the effect of 17beta-oestradiol on their cardiovascular response to pharmacological agents that block the formation of angiotensin II. Ten-week-old SHRs were randomly assigned to the following groups: intact, ovariectomized, and ovariectomized treated with 17beta-oestradiol (1.5 mg delivered over 60 days) and/or captopril (5 mg kg(-1) day(-1) for 8 weeks). Systolic blood pressure was determined from the time of ovariectomy up to 18 weeks of age, at which time endothelial function and microvascular density in skeletal muscle were evaluated. Both 17beta-oestradiol and captopril prevented development of hypertension in ovariectomized rats. Furthermore, coadministration of both drugs had a greater antihypertensive effect than either one alone. Acetylcholine-induced vasodilatation was impaired in ovariectomized SHRs, and the response was improved by treatment with 17beta-oestradiol and/or captopril. In addition, 17beta-oestradiol replacement in ovariectomized rats enhanced the effect of captopril on acetylcholine-induced vasodilatation. Ovariectomized rats also showed lower microvascular density than intact rats, an effect that was prevented by 17beta-oestradiol replacement or captopril treatment and, to a significantly larger extent, by coadministration of both. We concluded that both 17beta-oestradiol and captopril attenuated the development of hypertension and improved the impairment in microvascular density of ovariectomized SHRs. Moreover, when simultaneously administered, oestradiol and captopril had an additive effect on blood pressure and the microvasculature.

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.

Ambulatory blood pressure monitoring and active renin in menopausal women treated with amlodipine and hormone replacement therapy

The aim of this study was to follow up the effect of an 8-week treatment with amlodipine given alone or in combination with hormone replacement therapy (HRT) on blood pressure and active renin in postmenopausal women with mild to moderate arterial hypertension using both conventional clinical blood pressure measurements and ambulatory blood pressure monitoring. Twenty-nine hypertensive menopausal women were divided randomly into two groups according to the treatment regimens: amlodipine and amlodipine plus HRT. The combination with HRT led to normalization of 24-h and daytime systolic and diastolic blood pressure. In contrast to the group treated with amlodipine alone, where a significant fall only of systolic night-time blood pressure was observed, in the group treated with amlodipine plus HRT both systolic and diastolic night-time blood pressure decreased significantly. Active renin did not change significantly after treatment in both groups. Triglycerides decreased significantly and high-density lipoprotein-cholesterol increased significantly only after amlodipine treatment. There were no significant differences in serum total cholesterol and low-density lipoprotein-cholesterol after HRT plus amlodipine. In conclusion, amlodipine is effective in reducing blood pressure in postmenopausal women. The maintenance of a normal circadian blood pressure pattern was influenced by HRT.

Effects of Dietary Intake of Soy Protein and Isoflavones on Cardiovascular Disease Risk Factors in High Risk, Middle-Aged Men in Scotland

OBJECTIVE

To investigate the effects of soy protein and isoflavones on blood pressure (BP) and cholesterol levels among high risk middle-aged Scottish men.

DESIGN

A randomized, double-blind, placebo-controlled, parallel-group dietary intervention study

SETTING

Inhabitants on Isles of Lewis and Harris in Scotland

SUBJECTS

Sixty-one men with relatively higher BP and/or total cholesterol (TC) levels aged 45 to 59 went through the dietary intervention.

INTERVENTION

Diets containing at least 20 g of soy protein and 80 mg of isoflavones were compared to the placebo diets. Intervention period was 5 weeks duration.

RESULTS

Significant difference was found in 24-hour urinary isoflavone excretion between the two groups after intervention. Significant reductions from the baselines were observed in systolic BP (SBP) and diastolic BP (DBP), TC and non-high density lipoprotein cholesterol (non-HDL-C) in the soy-containing diet group, but not in the olive oil containing active placebo group. Significant increases in high density lipoprotein cholesterol (HDL-C) were observed in both groups.

CONCLUSION

Dietary intakes of soy protein (at least 20 g) and isoflavones (at least 80 mg) for 5 weeks would be effective in reducing CHD risk among high-risk, middle-aged men.

Postovariectomy Hypertension Is Linked to Increased Renal AT1Receptor and Salt Sensitivity

The functional balance between angiotensin II (Ang II) and nitric oxide (NO) plays a key role in modulating salt sensitivity. Estrogen has been shown to downregulate angiotensin type 1 (AT1) receptor expression and to increase the bioavailability of endothelium-derived NO, which decreases AT1 receptor expression. The present study tests the hypothesis that in the presence of genetic salt sensitivity, deficiency of endogenous estrogens after ovariectomy (OVX) fosters an upregulation of Ang II. Female Dahl salt-resistant (DR), Dahl salt-sensitive (DS), Wistar-Kyoto (WKY), and spontaneously hypertensive (SHR) rats underwent bilateral OVX or sham surgery (SHX) and were fed a normal salt diet (0.5% NaCl) for 14 weeks. Systolic blood pressures were measured every 2 weeks and were not significantly different between OVX and SHX for DR, WKY, and SHR groups. However, at the end of 14 weeks of normal salt diet, hypertension developed in DS OVX but not SHX rats (160+/-3 versus 136+/-3 mm Hg; P<0.05). Hypertension also developed in DS OVX rats pair-fed a normal salt diet (166+/-7 mm Hg). Development of hypertension in DS OVX rats was prevented by estrogen replacement (132+/-3 mm Hg), AT1 receptor blockade (119+/-3 mm Hg), or feeding a very low salt diet (0.1% NaCl; 129+/-4 mm Hg). Renal AT1 receptor protein expression was significantly elevated 2-fold in DS OVX relative to SHX rats and was prevented by estrogen replacement. These data strongly suggest that after OVX in salt-sensitive rats there is a lower threshold for the hypertensinogenic effect of salt that is linked to an activation of Ang II.