Relationship of menopause to serum cholesterol and arterial blood pressure in some Nigerian women

Integrated metagenome and metabolome analyses of blood pressure studies in early postmenopausal Chinese women

OBJECTIVE

We carried out sensitivity analyses on gut microbiota metagenomic sequencing, untargeted metabolome, targeted metabolome for short-chain fatty acids (SCFAs) and human whole genome sequencing from 402 early postmenopausal Chinese women to search for early omics-biomarkers and gain novel insights into the potential mechanisms of BP regulation in postmenopausal women.

METHODS

Clusters of co-abundant gut bacterial species and serum untargeted metabolites were identified by weighted gene co-expression network analysis (WGCNA). Partial least square analysis and joint analysis were performed to detect BP-associated omics-variables. Partial Pearson correlation was conducted to identify the interactions of microbe--host for host BP variation. Mendelian randomization analysis and causal inference test were used to examine causal relationships among gut microbiota, metabolites and BP variation.

RESULTS

In the present study, 651 bacterial species and 296 metabolites were binned into 53 and 26 co-abundance clusters by WGCNA, respectively. Then, we totally identified four gut bacterial species, one host metabolites and two SCFAs that were significantly associated with both SBP and DBP. Moreover, we found that gut microbiota would play important roles in host metabolic activity. Finally, our results revealed that increased Bacteroides fragilis could elevate BP via decreased caproic acid, and phenylacetylglutamine mediated the causal relationships of both B. fragilis and Clostridium sp.CAG.226 on DBP variation.

CONCLUSION

Multi-omics datasets integration has the potential to capture complementary effect and their interactions for BP variation, revealed the potential pathogenesis of BP variation and may be useful for studying other complex diseases/traits.

Administration of 17β-estradiol to ovariectomized obese female mice reverses obesity-hypertension through an ACE2-dependent mechanism

We recently demonstrated that female mice are resistant to the development of obesity-induced hypertension through a sex hormone-dependent mechanism that involved adipose angiotensin-converting enzyme 2 (ACE2). In this study, we hypothesized that provision of 17β-estradiol (E2) to ovariectomized (OVX) high-fat (HF)-fed female hypertensive mice would reverse obesity-hypertension through an ACE2-dependent mechanism. Pilot studies defined dose-dependent effects of E2 in OVX female mice on serum E2 concentrations and uterine weights. An E2 dose of 36 μg/ml restored normal serum E2 concentrations and uterine weights. Therefore, HF-fed OVX female Ace2(+/+) and Ace2(-/-) mice were administered vehicle or E2 (36 μg/ml) for 16 wk. E2 administration significantly decreased body weights of HF-fed OVX female Ace2(+/+) and Ace2(-/-) mice of either genotype. At 15 wk, E2 administration decreased systolic blood pressure (SBP) of OVX HF-fed Ace2(+/+) but not Ace2(-/-) females during the light but not the dark cycle. E2-mediated reductions in SBP in Ace2(+/+) females were associated with significant elevations in adipose ACE2 mRNA abundance and activity and reduced plasma ANG II concentrations. In contrast to females, E2 administration had no effect on any parameter quantified in HF-fed male hypertensive mice. In 3T3-L1 adipocytes, E2 promoted ACE2 mRNA abundance through effects at estrogen receptor-α (ERα) and resulted in ERα-mediated binding at the ACE2 promoter. These results demonstrate that E2 administration to OVX females reduces obesity-induced elevations in SBP (light cycle) through an ACE2-dependent mechanism. Beneficial effects of E2 to decrease blood pressure in OVX obese females may result from stimulation of adipose ACE2.

17beta-estradiol inhibits oleic acid-induced rat VSMC proliferation and migration by restoring PGC-1alpha expression

Estrogen shows a vasoprotective role through inhibiting the proliferation and migration of vascular smooth muscle cells (VSMCs). The mechanism underlying the effect of estrogen, however, is not completely understood. Here, we explored the role of peroxisome proliferator-activated receptor-gamma (PPARgamma) coactivator-1alpha (PGC-1alpha) in estrogen-mediated vasoprotection. Firstly, we showed that oleic acid (OA) decreased PGC-1alpha expression while stimulating VSMC proliferation and migration. In contrast, administration of VSMCs with 17beta-estradiol (E(2), 1 or 10nM) significantly restored OA-decreased PGC-1alpha expression, treatment with 10nM E(2) almost completely abolished OA-induced VSMC proliferation and migration. Secondly, by using PGC-1alpha siRNA, the inhibitory effect of E(2) on VSMC growth is strongly reduced via suppressing PGC-1alpha expression, indicating that E(2) may exert its role through restoring PGC-1alpha. Finally, E(2) (10nM) treatment inhibits OA-induced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation, however, suppression of PGC-1alpha expression abolishes this inhibitory effect of E(2). Our findings demonstrate for the first time that in OA-stimulated rat VSMCs, treatment with E(2) (1 or 10nM) diminishes VSMC proliferation and migration via restoring OA-decreased PGC-1alpha expression. This observation offers a novel molecular basis of the vasoprotective effect of estrogen.

Menopause does not affect blood pressure and risk profile, and menopausal women do not become similar to men

OBJECTIVE

Menopause is considered to be a cardiovascular risk factor, but this belief is based on opinions rather than on evidence. Confounding effects of age are often neglected.

DESIGN

Population-based study with further subanalysis of case-to-case age-matched cohorts of men and fertile and menopausal women.

SETTING

Epidemiology in primary, public, institutional frame.

PARTICIPANTS

Nine thousand three hundred and sixty-four men and women aged 18-70 years representative of Italian general population followed-up for 18.8 +/- 7.7 years.

MAIN OUTCOME MEASURES

Blood pressure (BP), prevalence and incidence of hypertension, serum total, high-density lipoprotein and low-density lipoprotein cholesterol, glucose tolerance, body adiposity, vascular reactivity, target organ damage, overall and cardiovascular mortality and morbidity, by gender and by menopausal status.

RESULTS

Cross-sectional: crude BP, pressor response to cold, orthostatic BP decrease, BMI, skinfold thickness, fasting and postload blood glucose and insulin, serum lipids, left ventricular mass, serum creatinine, microalbuminuria and augmetantion index were higher in menopausal than in fertile women, and comparable in menopausal women and men, a difference that was no longer present when adjusting for age or considering age-matched cohorts. Longitudinal: BP increase during follow-up, cardiovascular mortality and morbidity were greater in menopausal than in fertile women, and comparable in menopausal women and men, a difference no longer present in age-matched cohorts. Menopausal status was rejected from multivariate Cox analysis also including age.

CONCLUSION

The cardiovascular effects usually attributed to menopause seem to be a mere consequence of the older age of menopausal women.

Blood pressure around the menopause: a population study

BACKGROUND

Hypertension is a major cardiovascular risk factor possibly explaining the excessive cardiovascular morbidity and mortality in postmenopausal women. Cross-sectional and longitudinal studies have explored this issue with diverging results. Our study sought to elucidate the impact of the menopause on blood pressure in a representative population sample.

METHODS

The study involved randomly selected 908 female residents of a Prague district, aged 45-54 years (respondence rate, 63.9%). Three definitions of the menopause were used: self-reported menstrual characteristics (premenopausal with the final menstrual period less than 60 days; late menopausal transition, with final menstrual period 60-365 days; and postmenopausal, final menstrual period more than 365 days before the examination), levels of follicle-stimulating hormone (< or = 40 IU/l for premenopausal and more than 40 IU/l for postmenopausal women), and both.

RESULTS

Age-adjusted and BMI-adjusted systolic blood pressure and diastolic blood pressure did not differ among the groups regardless of the definition of menopause. There was also no difference in the prevalence of hypertension and in the age-adjusted and BMI-adjusted odds ratio for hypertension. Multiple regression analysis testing the association between systolic blood pressure and diastolic blood pressure, and age, BMI, heart rate, smoking, and antihypertensive medication explained a rather small proportion of the BP variation. No correlation was found between BP and age in either subgroup; the closest correlation was always found between BP and BMI.

CONCLUSION

In our rather homogeneous representative population random sample of women around the menopause, the rise in blood pressure after the menopause appeared to be due to increased BMI rather than to ovarian failure per se.

Hypertension, Menopause, and Coronary Artery Disease Risk in the Women’s Ischemia Syndrome Evaluation (WISE) Study

OBJECTIVES

We evaluated whether the relationship between hypertension, other cardiac risk factors, and coronary artery disease (CAD) is modulated by menopausal status and/or age.

BACKGROUND

The relative contribution of age versus menopausal status in the development of CAD in women remains unclear.

METHODS

We compared systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and traditional cardiac risk factors for CAD in premenopausal (n = 123) and postmenopausal (n = 482) women undergoing coronary angiography for suspected ischemia. To assess the relative contribution of age versus menopausal status, we fit a hypertension-menopausal status interaction term and adjusted for age.

RESULTS

There were similar relationships with regard to traditional coronary risk factors and angiographic CAD in premenopausal versus postmenopausal women, with few exceptions. Twenty percent of premenopausal women had angiographic CAD versus 31% of postmenopausal women (p = 0.02). Premenopausal women had lower mean (standard deviation) SBP (132 [25] vs. 139 [20] mm Hg; p < 0.0001) and lower PP (54 [18] vs. 62 [18] mm Hg; p < 0.0001) compared to postmenopausal women; however, multivariable analyses revealed that SBP was a risk factor for CAD in premenopausal (p = 0.002) but not postmenopausal women (p = 0.13), and regression slopes were significantly different (p = 0.04). This interaction effect remained after age adjustment, suggesting independent risk contribution from both age and menopausal status. A similar slope difference was observed for PP (p = 0.03) but not for DBP.

CONCLUSIONS

Among women undergoing angiography for suspected ischemia, elevated SBP and PP are potent risk factors in premenopausal women. The results suggest that identification of hypertension in premenopausal women dictates additional CAD risk factor assessment and management.

Menopause-related blood pressure increase and its relationship to age and body mass index: the SIMONA epidemiological study

BACKGROUND

Menopause is commonly associated with some blood pressure (BP) rise, but cross-sectional or longitudinal studies completed so far were often too small and were unable to indicate whether this BP increase is really dependent on menopause, or was caused by age or changes in body mass index (BMI).

METHODS AND RESULTS

The SIMONA study (Study on Hypertension Prevalence in Menopause in the Italian population) was a large cross-sectional study on 18 326 women of age range 46-59 years, consecutively seen by 302 practitioners all over Italy, and representing 60% of the women of that age in the National Health care list of those doctors. BP was measured three times in the seated position by the same automatic machine, and demographic and clinical data were taken. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were slightly but significantly higher in postmenopausal than premenopausal and perimenopausal women, but so were age and BMI. Within seven biannual strata, differences in age and BMI were minimized, but SBP/DBP remained significantly higher (by 3.4/3.1 mmHg) in postmenopausal than in premenopausal subjects in the youngest stratum (46-47 years), and was also significantly higher in the stratum 48-49 years. The differences remained significant after the exclusion of 1809 women with surgical menopause or 695 women with cardiovascular disease. Even when the confounding effects of age, BMI, smoking and contraceptive or replacement therapies were excluded by analysis of covariance, menopause was significantly and positively associated with SBP and DBP (approximately 2 mmHg difference in the age range 46-49 years).

CONCLUSION

Menopause is associated with a slightly but significantly higher BP, even after adjustment for age and BMI, as well as other confounding factors, but the association is evident only in the younger end of the age range related to menopause.

Menopause induced by oophorectomy reveals a role of ovarian estrogen on the maintenance of pressure homeostasis

OBJECTIVES

Following spontaneous menopause women show a greater increase in systolic and diastolic blood pressure than men of the same age. The aim of the present study was to assess the effect of acute ovarian hormone withdrawal and replacement on blood pressure and forearm blood flow.

METHODS

We studied 18 fertile middle-aged normotensive women (48 +/- 1.5 years, range 46-51 years) 1 week prior and 1 month subsequent to bilateral oophorectomy by means of 24-h blood pressure monitoring and strain-gauge venous occlusion plethysmography. Eighteen subjects who had undergone hysterectomy with ovarian sparing, matched for age and biophysical characteristics, were used as a control group. All women were free from cardiovascular risk factors or disease.

RESULTS

Oophorectomy increased the mean values of 24 h (P < 0.001), daytime (P < 0.05), and nighttime (P < 0.01) diastolic blood pressure and nighttime systolic blood pressure (P < 0.01). Blood pressure increase was associated with a rise in forearm vascular resistance (P < 0.01). No significant changes in either blood pressure or forearm vascular resistance values were observed in hysterectomized women. In 16 oophorectomized women a 3-month estrogen replacement therapy (ERT) (17beta-estradiol, 100 mcg/day by transdermal patches) brought blood pressure and forearm vascular resistance values to a level comparable to that recorded before intervention.

CONCLUSIONS

Surgically-induced menopause causes an increase in peripheral vascular resistance and blood pressure suggesting a role of ovarian hormones in the homeostatic pressure modulation. Recovery of the baseline condition after ERT suggests that the accelerated increase in blood pressure after menopause is due to ovarian and above all estrogen insufficiency.

Is there a menopausal metabolic syndrome?

Estradiol-17 beta has beneficial effects on a range of metabolic risk factors for coronary heart disease and the decline in estrogen concentrations at the menopause would be expected to have adverse effects. Review of the literature on effects of the menopause and of estradiol-17 beta provides evidence for the following changes occurring at or after the menopause: increased total cholesterol and triglycerides; decreased high density lipoprotein (HDL) and HDL subfraction 2; increased low density lipoprotein, particularly in the small, dense subfraction; increased lipoprotein (a); increased insulin resistance; decreased insulin secretion; decreased insulin elimination; increased android fat distribution; impaired vascular function; increased factor VII and fibrinogen, and reduced sex-hormone binding globulin. Many of these changes will themselves have adverse effects on other metabolic risk factors. This complex of inter-correlated adverse changes in metabolic risk factors justifies identification of a distinct menopausal metabolic syndrome which originates in estrogen deficiency and which could contribute to the increased risk of coronary heart disease seen in postmenopausal women. Estrogen replacement can diminish the expression of this syndrome.

Effects of menopause on trends of serum cholesterol, blood pressure, and body mass index

BACKGROUND

To elucidate the impact of menopause on coronary risk factors, we determined the trends of serum cholesterol (mg/dL), blood pressure (BP, mm Hg), and body mass index (BMI, kg/m2) and investigated whether menopause affects these trends in women in Nagasaki, Japan.

METHODS AND RESULTS

Trends of cholesterol, systolic BP (SBP), and BMI from 9 years before menopause through 9 years after menopause in 579 women with natural menopause (ranging in age from 40.2+/-3.1 to 57.9+/-3.1 years; age at menopause, 49.4+/-3.0 years) and 134 women with surgical menopause (hysterectomy with or without bilateral oophorectomy; ranging in age from 34.9+/-4.5 to 51.7+/-5.1 years; age at menopause, 42.9+/-5.0 years) and those in 579 and 134 age- and time-matched male subjects (ranging in age from 40.1+/-3.1 to 57.8+/-3.2 years and from 35.2+/-4.5 to 51.6+/-5.0 years, respectively) in Nagasaki were determined by rearrangement of the data from 1958 to 1989 with time of menopause as the datum line. Although cholesterol tended to increase with age in both sexes, it increased significantly in women from 3 years before natural menopause to 1 year after natural menopause and from 1 year before surgical menopause to 1 year after surgical menopause. SBP and BMI did not exhibit a significant increase in relation to natural or surgical menopause. In male subjects, no significant increase of cholesterol, SBP, or BMI was observed at the age corresponding to natural or surgical menopause.

CONCLUSIONS

Natural menopause and surgical menopause exert an effect only on cholesterol, and an increase in cholesterol precedes natural menopause by 3 years and occurs at the time of surgical menopause.

Correlates of serum lipids in a lean black population

Exposure to an urban, sedentary work environment and higher socioeconomic status (SES) may stimulate adoption of Westernized lifestyles by populations in developing countries reversing the historically low risk for coronary heart disease. In a study of serum lipids in 1407 Nigerian civil servants, aged 25-54 years, we found a more atherogenic lipid profile among higher SES males and females compared with lower SES (LDL-cholesterol, 113 vs. 97 mg/dl, males, 125 vs. 114 mg/dl, females). Mean body mass index (BMI, kg/m2) in higher and lower SES was 22.6 and 21.3, respectively, males, and 24.7 and 24.4, respectively females. A strong relationship was observed between BMI and lipids although this relationship was absent among the leanest half of the population (BMI < 21.8). In multiple regression, SES and BMI were both strong and independent predictors of cholesterol. Both high and low SES consumed a typical Nigerian low fat, high carbohydrate diet, but somewhat higher meat, milk and egg intake suggested that some Westernization of the diet had occurred among the higher SES. Physical activity was lower among the higher SES. We conclude that SES related changes in lifestyle contribute to substantially higher total and LDL-cholesterol even in a generally lean population consuming a low fat diet.

Natural menopause and cardiovascular disease risk factors. The Poland and US Collaborative Study on Cardiovascular Disease Epidemiology

Changes in risk factor levels associated with menopause have been reported in many studies in the United States and western Europe, where estrogen replacement therapy and surgical menopause are common. We studied risk factor associations in Polish women, for whom estrogen replacement therapy and surgical menopause are uncommon. The 357 postmenopausal women had higher total cholesterol levels (0.43 mmol/L) and low-density-lipoprotein cholesterol levels (0.36 mmol/L than did the 372 premenopausal women of similar ages. Triglycerides, high-density-lipoprotein cholesterol, body mass index, and blood pressure did not differ by menopausal status. We conclude that natural menopause is associated with higher levels of total and low-density-lipoprotein cholesterol levels. Natural menopause is not associated with large changes in other risk factors in this sample.