Postmenopausal hypertension and sodium sensitivity

The Particularities of Arterial Hypertension in Female Sex: From Pathophysiology to Therapeutic Management

Arterial hypertension is the most important modifiable cardiovascular risk factor and a major cause of cardiovascular mortality worldwide. In daily clinical practice, the hypertensive patient is often treated in a uniform way, thus ignoring the significant effects of sex on several aspects of hypertension, including its prevalence, pathophysiology, response to antihypertensive treatment, and outcomes. Along with the immune response and several cardiometabolic risk factors that frequently coexist, the substantial hormonal changes during a woman's life cycle are among the main pathophysiological mechanisms driving hypertension in women. Concurrently, women exhibit increased cardiovascular risk at lower blood pressure (BP) levels compared to age-matched men and present certain disparities in the incidence of cardiovascular events and subsequent hypertension-related cardiovascular prognosis. In addition, women respond differently to antihypertensive treatment, experience more drug-related side effects, and exhibit lower rates of BP control compared to men. Currently, international guidelines propose the same targets and the same therapeutic algorithms for the treatment of hypertension in both sexes without taking into account the sex differences that exist. In this review, we aim to describe certain particularities of arterial hypertension in the female sex, moving from pathophysiological aspects to clinical and therapeutical management.

Targeting the sympathetic nervous system with the selective imidazoline receptor agonist moxonidine for the management of hypertension: an international position statement

Hypertension is often linked with metabolic risk factors that share common pathophysiological pathways. Despite wide-spread availability of multiple drug classes, optimal blood pressure (BP) control remains challenging. Increased central sympathetic outflow is frequently neglected as a critical regulator of both circulatory and metabolic pathways and often remains unopposed therapeutically. Selective imidazoline receptor agonists (SIRAs) effectively reduce BP with a favorable side effect profile compared with older centrally acting antihypertensive drugs. Hard outcome data in hypertension, such as prevention of stroke, heart and kidney diseases, are not available with SIRAs. However, in direct comparisons, SIRAs were as effective as angiotensin-converting enzyme inhibitors, β-blockers, calcium channel blockers, and diuretics in lowering BP. Other beneficial effects on metabolic parameters in hypertensive patients with concomitant overweight and obesity have been documented with SIRAs. Here we review the existing evidence on the safety and efficacy of moxonidine, a widely available SIRA, compared with common antihypertensive agents and provide a consensus position statement based on inputs from 12 experts from Europe and Australia on SIRAs in hypertension management.

Erythrocyte glycocalyx sensitivity to sodium is associated with salt sensitivity of blood pressure in women but not men

Background

While salt sensitivity of blood pressure (SSBP) is a risk factor for hypertension, end-organ damage and death, most studies are conducted in western countries and in White people. We previously found that the prevalence of SSBP in Blacks living in Sub-Saharan Africa is as high as 75-80% like what has been reported in the west. Erythrocyte glycocalyx sensitivity to sodium (eGCSS), a marker of sodium-induced damage to the erythrocyte and vascular endothelial glycocalyx is thought to be related to blood pressure perturbations associated with salt intake. We hypothesized that SSBP correlates with eGCSS differently in men and women in Black people.

Methods

We conducted a cross sectional study using data from our recent clinical trial from Livingstone University Teaching Hospital among 117 normotensive young adults. We used a "salt blood test" to determine eGCSS and an immediate pressor response to oral salt (IPROS) for the diagnosis of SSBP.

Results

The proportion of males were equal to females and the median age (interquartile range) of the participants was 29 (22-45) years. The eGCSS scores were higher in salt-resistant females compared to salt-sensitive females and males. eGCSS correlated negatively with SSBP (AOR 0.98, 95% CI 0.97-0.99, p = 0.008), however, this relationship was driven by female sex and abrogated by male sex. Although blood pressure elevations exhibited a sustained bimodal pattern in both sexes, in males, systolic and diastolic blood pressure never returned to baseline during the time course as it did in females.

Conclusion

In this study, eGCSS correlated negatively with SSBP in black women but not in black men and the pressor response to dietary salt was significantly higher in men compared to women. These results suggest that women tend to have a higher disruption of the vascular endothelial glycocalyx by an acute salt load, implying that acute changes in blood pressure may not be driven directly by the endothelial glycocalyx. Our findings suggest a novel mechanism linking eGCSS and SSBP with potential implications for sex differences in salt-induced cardiovascular disease.Clinical trial registration: https://clinicaltrials.gov/, identifier [NCT04844255].

Role of Female Sex Hormones and Immune Response in Salt-Sensitive Hypertension Development: Evidence from Experimental Models

PURPOSEOF REVIEW

Female sex hormones have systemic effects unrelated to their reproductive function. We describe experiences of different research groups and our own, on aspects related to the importance of female sex hormones on blood pressure (BP) regulation and salt-sensitivity-mediated BP response and salt sensitivity without alterations in BP, as well as renal sodium handling and interactions with the immune system.

RECENT FINDINGS

Changes in sodium intake in normotensive premenopausal women cause more BP variations than in men. After menopause, women often develop arterial hypertension (HT) with a profile of sodium sensitivity. Besides, experimental results have shown that in adult rat models resembling the postmenopausal hormonal state induced by ovariectomy, controlling BP is not enough to avoid renal and other tissue infiltration with immune cells, which does not occur when sodium intake is low or normal. Therefore, excess sodium promotes an inflammatory state with the involvement of immune cells. The evidence of activation of adaptive immunity, besides changes in T cell subpopulations, includes changes in sodium transporters and receptors. More studies are needed to evaluate the particular sodium sensitivity of women and its meaning. Changes in lifestyle and sodium intake reduction are the main therapeutic steps. However, to face the actual burden of salt-sensitive HT in postmenopausal women and its associated inflammatory/immune changes, it seems reasonable to work on immune cell activity by considering the peripheral blood mononuclear cell phenotypes of molecules and transport proteins related to sodium handle, both to screen for and treat cell activation.

Stroke vs. Preeclampsia: Dangerous Liaisons of Hypertension and Pregnancy

Stroke during pregnancy and preeclampsia are two distinct but interrelated medical conditions, sharing a common denominator-blood control failure. Along with cardiovascular diseases, diabetes, dyslipidemia, and hypercoagulability, hypertension is undoubtedly a major risk factor associated with stroke. Even though men have higher age-specific stroke rates, women are facing higher life-long stroke risk, primarily due to longer life expectancy. Sex hormones, especially estrogen and testosterone, seem to play a key link in the chain of blood pressure control differences between the genders. Women affected with stroke are more susceptible to experience some atypical stroke manifestations, which might eventually lead to delayed diagnosis establishment, and result in higher morbidity and mortality rates in the population of women. Preeclampsia is a part of hypertensive disorder of pregnancy spectrum, and it is common knowledge that women with a positive history of preeclampsia are at increased stroke risk during their lifetime. Preeclampsia and stroke display similar pathophysiological patterns, including hypertension, endothelial dysfunction, dyslipidemia, hypercoagulability, and cerebral vasomotor reactivity abnormalities. High-risk pregnancies carrying the burden of hypertensive disorder of pregnancy have up to a six-fold higher chance of suffering from stroke. Resemblance shared between placental and cerebral vascular changes, adaptations, and sophisticated auto-regulatory mechanisms are not merely coincidental, but they reflect distinctive and complex cardiovascular performances occurring in the maternal circulatory system during pregnancy. Placental and cerebral malperfusion appears to be in the midline of both of these conditions; placental malperfusion eventually leads to preeclampsia, and cerebral to stoke. Suboptimal performances of the cardiovascular system are proposed as a primary cause of uteroplacental malperfusion. Placental dysfunction is therefore designated as a secondary condition, initiated by the primary disturbances of the cardiovascular system, rather than an immunological disorder associated with abnormal trophoblast invasion. In most cases, with properly and timely applied measures of prevention, stroke is predictable, and preeclampsia is a controllable condition. Understanding the differences between preeclampsia and stroke in pregnancy is vital for healthcare providers to enhance their clinical decision-making strategies, improve patient care, and promote positive maternal and pregnancy outcomes. Management approaches for preeclampsia and stroke require a multidisciplinary approach involving obstetricians, neurologists, and other healthcare professionals.

Prevalence and sociodemographic determinants of selected noncommunicable diseases among the general population of Cyprus: A large population-based cross-sectional study

Background

Noncommunicable diseases (NCDs) are the leading cause of morbidity and mortality worldwide. The aim of this study was to determine the prevalence of NCDs among the population of Cyprus and to identify the distribution of the socioeconomic and demographic determinants among individuals with the most frequent NCDs.

Methods

A cross-sectional study was conducted using stratified sampling. Socioeconomic and demographic characteristics and the presence of NCDs were collected through a standardized questionnaire. The diseases were classified using the 10th revision of the International Classification of Diseases (ICD-10).

Results

In total, 1140 individuals participated in the study, among whom 590 (51.7%) had at least one chronic disease. The most prevalent NCDs were hyperlipidemia (17.4%), hypertension (12.9%), and thyroid diseases (8.4%). We identified more males than females with hyperlipidemia aged 25-44 years old and >65 years old (p = 0.024), more males compared to females with hypertension (p = 0.001) and more females compared to males with thyroid diseases (p < 0.001). Individuals with hypertension and hyperlipidemia were more likely to be married, to have completed a higher education, and to have a high annual income.

Discussion

In Cyprus, the majority of the general population had at least one NCD. Hyperlipidemia, hypertension, and thyroid disease are relatively common, even at younger ages, highlighting the need for the development of public health programs aimed at addressing and preventing NCDs.

Sex Differences in Offspring of Preeclamptic Pregnancies

A poor uterine environment causes changes in fetal development that affect the health of offspring long-term. Although there are multiple pathways that contribute to the development of cardiovascular and neurological disease, low birth weight or fetal growth restriction (FGR) predisposes offspring to these diseases. There is a link between fetal exposure to adverse influences and hypertension later in life. Many epidemiological studies support the link between fetal life and the risk of disease later in life. Experimental models have sought to provide mechanistic proof of this link while simultaneously investigating potential therapeutics or treatment pathways. Preeclampsia (PE), one of several hypertensive disorders in pregnancy, is a leading cause of morbidity and mortality for both the mother and fetus. Studies have shown that PE is a state of chronic inflammation and there is an imbalance between pro-inflammatory and regulatory immune cells and mediators. There is no cure for PE beyond the delivery of the fetal-placental unit, and many PE pregnancies result in FGR and preterm birth. Epidemiological data demonstrate that the sex of the offspring is correlated with the degree of cardiovascular disease that develops with the age of the offspring yet few studies examine the effect of sex on the development of neurological disorders. Even fewer studies examine the effects of therapeutics on offspring of different genders following a PE pregnancy. Moreover, there remain significant gaps in knowledge concerning the role the immune system plays in FGR offspring developing hypertension or neurovascular disorders later in life. Therefore, the purpose of this review is to highlight current research on sex differences in the developmental programming of hypertension and neurological disorders following a PE pregnancy.

Mechanisms of sex and gender differences in hypertension

The mechanisms that control blood pressure are multifaceted including the sympathetic nervous system and the renin-angiotensin system leading to vasoconstriction and sodium reabsorption that causes a shift in the pressure-natriuesis relationship to higher blood pressures. Sex steroids can affect these mechanisms either directly or indirectly, and the effects may be different depending on the sex of the individual. This review will discuss some of the major blood pressure-controlling mechanisms and how sex steroids may affect them and the need for future studies to better clarify the mechanisms responsible for sex and gender differences in blood pressure control. New mechanisms that are identified, along with what is already known, will provide better tools for treatment of hypertension in men and women of all ethnicities and decrease the risk of cardiovascular disease in the future.

Serum Progesterone is Negatively Associated with Hypertension and Blood Pressure Indicators Among Men and Postmenopausal Women

Sex hormones have been shown to be negatively associated with hypertension, but the relationship between serum progesterone levels and hypertension has not been adequately studied. Therefore, we aimed to evaluate the association between progesterone and hypertension among Chinese rural adults. A total of 6222 participants were recruited, which included 2577 men and 3645 women. The concentration of serum progesterone was detected by liquid chromatography-mass spectrometer system (LC-MS/MS). Logistic regression and linear regression were used to assess the associations between progesterone levels and hypertension and blood pressure related indicators, respectively. Constrained splines were used to fit the dose-response relationships of progesterone with hypertension and blood pressure related indicators. Moreover, the interactive effects of several lifestyle factors and progesterone were identified by a generalized linear model. After fully adjusting the variables, progesterone levels were inversely associated with hypertension in men [odds ratio (OR): 0.851, 95% confidence interval (CI): 0.752, 0.964]. Among men, a 2.738 ng/ml increase in progesterone was associated with a 0.557 mmHg decrease in diastolic blood pressure (DBP) (95% CI: -1.007, -0.107) and a 0.541 mmHg decrease in mean arterial pressure (MAP) (95% CI: -1.049, -0.034), respectively. Similar results were observed in postmenopausal women. Interactive effect analysis showed that only a significant interaction was observed between progesterone and educational attainment on hypertension in premenopausal women (p=0.024). Elevated levels of serum progesterone were associated with hypertension in men. Except for premenopausal women, a negative association of progesterone with blood pressure related indicators was observed.

Effects of sea salt intake on metabolites, steroid hormones, and gut microbiota in rats

High salt intake is positively linked to many health problems, but the effect of mineral-rich sea salt (SS) has rarely been studied. To better understand the physiological effects of SS intake, the changes in general characteristics, metabolites, steroid hormones, and gut microbiota of SS-fed rats were investigated. Male rats were fed either a normal diet (ND, control) or ND containing 1% SS or 4% SS for 5 weeks. SS intake decreased fat, spleen, liver, and body weight, and increased blood urea nitrogen (BUN), water intake, and gut salt content. Accumulated gut salt content led to a decrease in beneficial bacteria, such as Lachnospiraceae and Lactobacillus, but an increase in potentially harmful bacteria, resulting in a change in lipid metabolites associated with gut health. Interestingly, most renal lysophosphatidylcholines (LPCs) associated with many renal functions were dramatically decreased and female hormones, such as estrogens, were significantly more altered than the male hormones by high SS intake. Although further investigation is needed, these data suggest that high SS intake could be positively linked to kidney dysfunction and gut health problems, and salt-related physiological changes may be sex-specific. Additionally, these data will be useful to better under-stand the physiological effects of SS intake.

Gender differences in the associations of circulating erythrocytes and hemoglobin with hypertension risk

OBJECTIVE

Studies on associations of erythrocytes parameters with hypertension risk are scarce. We aimed to examine associations of the erythrocytes parameters with the hypertension risk and potential effect modification by gender using data from the China Health and Nutrition Survey.

METHODS

A total of 5419 eligible participants (2468 men, 45.5%) without hypertension at baseline in 2009 were included and followed for a median of 6.1 years. Parameters of erythrocytes and hemoglobin were measured at baseline. Multivariable Cox proportional hazards models were used to estimate the hazard ratio for the associations between these parameters and hypertension risk. Data were collected from 2009 to 2015 and analyzed in 2021.

RESULTS

A total of 1178 incident cases of hypertension were identified during the follow-up. In women, erythrocytes and hemoglobin were positively associated with risk of hypertension, yielding the highest hazard ratio in the third quartile of 1.59 (95% confidence interval, 1.28-1.97, P trend < 0.001) for erythrocytes and in the fourth quartile of 1.64 (95% confidence interval, 1.23-2.17, P trend < 0.001) for hemoglobin compared with their first quartile, respectively. In addition, quartiles of erythrocytes and hemoglobin were not associated with risk of hypertension in men ( P trend > 0.050).

CONCLUSION

Erythrocytes and hemoglobin were associated with an increased risk of hypertension in women, but not in men. Our findings suggest that special attention for the prevention of hypertension should be given to those women with the moderate to high level of circulating erythrocytes and higher level of hemoglobin.

Alleviation of Metabolic Disturbance by Substituting Kanjang High in Bacillus for Salt through Modulation of Gut Microbiota in Estrogen-Deficient Rats

A high salt intake may exacerbate menopausal symptoms and substituting for different types of traditionally made kanjang (TMK; soy sauce) may prevent it. This study examined whether substituting salt with lyophilized TMK containing low and high Bacillus and biogenic amines in a high-fat diet might modulate the menopausal symptoms and the energy, glucose, and lipid metabolism in ovariectomized (OVX) rats. They were categorized into salt (Control), TMK with high Bacillus and low biogenic amines (HBLB), TMK with high Bacillus and high biogenic amines (HBHB), TMK with low Bacillus and low biogenic amines (LBLB), and TMK with low Bacillus and high biogenic amines (LBHB). Sham-operated rats consumed the same diet as the Control. HBLB, HBHB, and LBHB prevented increased tail skin temperature compared to the Control. HBHB and HBLB partially inhibited the increased weight gain and abdominal fat mass by reducing the food efficiency without changing the serum 17β-estradiol concentrations. Serum glucose and insulin concentrations and the insulin resistance index by the homeostatic model assessment for insulin resistance showed a positive association for weight gain. HBLB and HBHB decreased the serum malondialdehyde and tumor-necrosis factor-α levels. Hepatic triglyceride storage was lower in all TMK groups than in the Control, while hepatic glycogen accumulation was higher in the HBLB, HBHB, and LBHB groups than in the Control and LBLB groups. Accordingly, the mRNA expression of peroxisome proliferator-activated receptors-γ(PPAR-γ) was higher in the HBLB and HBHB groups compared to the Control, and that of fatty acid synthase was opposite to PPAR-γ expression. However, HBLB and HBHB improved dyslipidemia and insulin resistance compared to the Control, but their improvement did not reach that of the Normal-control. The acetic acid concentrations in the portal vein were lower in the LBLB than in the Control, while the butyric acid contents were higher in the LBHB and HBLB groups than in the Control. HBHB, HBLB, and LBHB elevated Akkermansia and Lactobacillus, and HBLB and LBLB increased Bacteroides and Ruminococcus compared to the Control. Polycyclic aromatic hydrocarbon degradation, bile acid synthesis, and unsaturated fatty acid biosynthesis were significantly higher in the HBLB group than in the Control group. In conclusion, substituting salts to TMK with a high Bacillus content regardless of the bioamine contents partially improved the menopausal symptoms and metabolic disturbance in estrogen-deficient animals.

The Role of Race, Sex, and Age in Circadian Disruption and Metabolic Disorders

Circadian rhythms are 24-hour internal biological cycles that play an important role in metabolism, and their disruption has been implicated in the development of diseases such as diabetes mellitus type 2, obesity, coronary artery disease, hypertension, and metabolic syndrome. This phenomenon is illustrated by increased rates of risk factors for cardiovascular disease in night shift workers. Race, sex, and age are factors that play a role in circadian rhythms and metabolic disorders. The focus of this review article is to assess the link between circadian rhythm physiology and metabolic disorders from a race, sex, and age perspective. Black Americans were noted to have shorter free-running circadian periods, or tau, increased cortisol levels, and poorer sleep habits compared to white Americans, possibly contributing to increased rates of obesity, hypertension, and hyperlipidemia. Women were also noted to have shorter tau, increased levels of proinflammatory gut bacteria, and reduced sleep quality compared to men, possibly leading to higher rates of obesity, metabolic syndrome, hypertension (in postmenopausal women), and nonalcoholic fatty liver disease. Older people were noted to have decreased expression of anti-inflammatory clock genes compared to younger people, possibly leading to increased rates of obesity, diabetes, hyperlipidemia, and hypertension. Groups that are at a higher risk for metabolic disorders such as black Americans, women, and the elderly may have internal time keeping systems that place them at a higher risk for developing abnormal hormonal and/or inflammatory pathways.

Acclimation to a High-Salt Diet Is Sex Dependent

Background Premenopausal women are less likely to develop hypertension and salt-related complications than are men, yet the impact of sex on mechanisms regulating Na+ homeostasis during dietary salt challenges is poorly defined. Here, we determined whether female rats have a more efficient capacity to acclimate to increased dietary salt intake challenge. Methods and Results Age-matched male and female Sprague Dawley rats maintained on a normal-salt (NS) diet (0.49% NaCl) were challenged with a 5-day high-salt diet (4.0% NaCl). We assessed serum, urinary, skin, and muscle electrolytes; total body water; and kidney Na+ transporters during the NS and high-salt diet phases. During the 5-day high-salt challenge, natriuresis increased more rapidly in females, whereas serum Na+ and body water concentration increased only in males. To determine if females are primed to handle changes in dietary salt, we asked the question whether the renal endothelin-1 natriuretic system is more active in female rats, compared with males. During the NS diet, female rats had a higher urinary endothelin-1 excretion rate than males. Moreover, Ingenuity Pathway Analysis of RNA sequencing data identified the enrichment of endothelin signaling pathway transcripts in the inner medulla of kidneys from NS-fed female rats compared with male counterparts. Notably, in human subjects who consumed an Na+-controlled diet (3314-3668 mg/day) for 3 days, women had a higher urinary endothelin-1 excretion rate than men, consistent with our findings in NS-fed rats. Conclusions These results suggest that female sex confers a greater ability to maintain Na+ homeostasis during acclimation to dietary Na+ challenges and indicate that the intrarenal endothelin-1 natriuretic pathway is enhanced in women.

Arterial stiffness and cardiometabolic health in omnivores and vegetarians: a cross-sectional pilot study

Objective

Arterial stiffness is a strong predictor of cardiovascular mortality, and often precedes elevations in blood pressure. This cross-sectional pilot study examined differences in arterial stiffness, blood pressure, cardiometabolic markers, anthropometric outcomes, and inflammation in vegetarians and matched omnivores. Participants were healthy, non-smoking adults (18–65 years old) adhering to either a vegetarian/vegan or omnivore diet. Omnivores were matched to vegetarians using broad body mass index (BMI) categories.

Results

Arterial stiffness trended higher in omnivores versus vegetarians (7.0 ± 1.5 and 6.8 ± 1.1 m/s, respectively; p = 0.073). This trend was mainly driven by the male omnivores (p = 0.006 for gender effect and p = 0.294 for eating pattern effect). Omnivores displayed higher HDL concentrations compared to vegetarians, 63.8 ± 18.5 and 55.2 ± 16.9 mg/dL; however, total cholesterol/HDL ratio did not vary significantly between groups; p = 0.310. In men, a vegetarian eating pattern may reduce arterial stiffness; however, this benefit may be limited in women, particularly those who are premenopausal. Future research should examine arterial stiffness and cardiometabolic health outcomes in younger versus older female vegetarians, as these data can provide valuable insights on the role of plant-based eating patterns on arterial stiffness and cardiometabolic health.

Effects of heavy metals on hypertension during menopause: a Korean community-based cross-sectional study

OBJECTIVE

To examine the associations between serum cadmium, lead, and mercury and hypertension in pre- and postmenopausal women.

METHODS

Serum heavy metal (cadmium, lead, and mercury) levels were analyzed in 7,226 randomly selected women who participated in Korean National Health and Nutrition Examination Surveys from 2009 to 2017. Odds ratios (ORs) for hypertension were calculated for log2-transformed serum heavy metal levels, median tertile levels of serum cadmium, mercury, and lead, and for interactions between heavy metal levels and tertiles, after covariate adjustment.

RESULTS

A doubling of serum cadmium was associated with hypertension in premenopausal (OR 2.47; 95% CI, 1.01-6.10, P = 0.049) and postmenopausal women (OR 1.70; 95% CI, 1.02-2.84, P = 0.043), and significant trends were observed for cadmium tertiles (P < 0.01). In premenopausal women, a two-fold increase in serum mercury increased the OR of hypertension by 3.08 (95% CI, 1.12-8.43, P = 0.029), and significant trends were also observed for serum mercury tertiles (P < 0.01). Interactions between serum cadmium, lead, and mercury levels in pre- and postmenopausal women were found to impact the prevalence of hypertension.

CONCLUSION

Given increasing exposure to heavy metals in Korea, further prospective study is needed to identify associations between heavy metal exposures, both separately and in combination, with the prevalence of cardiovascular disease risk factors in well-characterized cohorts of different populations and to determine means of preventing heavy metal exposure.

Dietary Magnesium Insufficiency Induces Salt-Sensitive Hypertension in Mice Associated With Reduced Kidney Catechol-O-Methyl Transferase Activity

[Figure: see text].

Female Sex, a Major Risk Factor for Salt-Sensitive Hypertension

PURPOSE OF REVIEW

High dietary salt is a significant contributor to essential hypertension in clinical populations. However, although clinical studies indicate a higher prevalence of salt sensitivity in women over men, knowledge of salt-sensitive mechanisms is largely restricted to males, and female-specific mechanisms are presently being elucidated.

RECENT FINDINGS

Male-specific mechanisms of salt-sensitive hypertension are well published and predominantly appear to involve dysfunctional renal physiology. However, emerging novel evidence indicates that aldosterone production is sex-specifically heightened in salt-sensitive hypertensive women and female rodent models, which may be regulated by intra-adrenal renin-angiotensin system activation and sex hormone receptors. In addition, new evidence that young females endogenously express higher levels of endothelial mineralocorticoid receptors (MRs) and that endothelial MR is a crucial mediator of endothelial dysfunction in females indicates that the aldosterone-endothelial MR activation pathway is a novel mediator of salt-sensitive hypertension. Heightened aldosterone levels and endothelial MR expression provide a 2-fold sex-specific mechanism that may underlie the pathology of salt-sensitive hypertension in women. This hypothesis indicates that MR antagonists may be a preferential treatment for premenopausal women diagnosed with salt-sensitive hypertension.

Role for ovarian hormones in purinoceptor-dependent natriuresis

BACKGROUND

Premenopausal women have a lower risk of hypertension compared to age-matched men and postmenopausal women. P2Y2 and P2Y4 purinoceptor can be considered potential contributors to hypertension due to their emerging roles in regulating renal tubular Na+ transport. Activation of these receptors inhibits epithelial Na+ channel activity (ENaC) via a phospholipase C (PLC)-dependent pathway resulting in natriuresis. We recently reported that activation of P2Y2 and P2Y4 receptors in the renal medulla by UTP promotes natriuresis in male and ovariectomized (OVX) rats, but not in ovary-intact females. This led us to hypothesize that ovary-intact females have greater basal renal medullary activity of P2 (P2Y2 and P2Y4) receptors regulating Na+ excretion compared to male and OVX rats.

METHODS

To test our hypothesis, we determined (i) the effect of inhibiting medullary P2 receptors by suramin (750 μg/kg/min) on urinary Na+ excretion in anesthetized male, ovary-intact female, and OVX Sprague Dawley rats, (ii) mRNA expression and protein abundance of P2Y2 and P2Y4 receptors, and (iii) mRNA expression of their downstream effectors (PLC-1δ and ENaCα) in renal inner medullary tissues obtained from these three groups. We also subjected cultured mouse inner medullary collecting duct cells (segment 3, mIMCD3) to different concentrations of 17ß-estradiol (E2, 0, 10, 100, and 1000 nM) to test whether E2 increases mRNA expression of P2Y2 and P2Y4 receptors.

RESULTS

Acute P2 inhibition attenuated urinary Na+ excretion in ovary-intact females, but not in male or OVX rats. We found that P2Y2 and P2Y4 mRNA expression was higher in the inner medulla from females compared to males or OVX. Inner medullary lysates showed that ovary-intact females have higher P2Y2 receptor protein abundance, compared to males; however, OVX did not eliminate this sex difference. We also found that E2 dose-dependently upregulated P2Y2 and P2Y4 mRNA expression in mIMCD3.

CONCLUSION

These data suggest that ovary-intact females have enhanced P2Y2 and P2Y4-dependent regulation of Na+ handling in the renal medulla, compared to male and OVX rats. We speculate that the P2 pathway contributes to facilitated renal Na+ handling in premenopausal females.

G protein-coupled estrogen receptor 1 as a novel regulator of blood pressure

The mechanisms underlying hypertension are multifaceted and incompletely understood. New evidence suggests that G protein-coupled estrogen receptor 1 (GPER1) mediates protective actions within the cardiovascular and renal systems. This mini-review focuses on recent advancements in our understanding of the vascular, renal, and cardiac GPER1-mediated mechanisms that influence blood pressure regulation. We emphasize clinical and basic evidence that suggests GPER1 as a novel target to aid therapeutic strategies for hypertension. Furthermore, we discuss current controversies and challenges facing GPER1-related research.

Sex differences in redox homeostasis in renal disease

Sex differences in redox signaling in the kidney present new challenges and opportunities for understanding the physiology and pathophysiology of the kidney. This review will focus on reactive oxygen species, immune-related signaling pathways and endothelin-1 as potential mediators of sex-differences in redox homeostasis in the kidney. Additionally, this review will highlight male-female differences in redox signaling in several major cardiovascular and renal disorders namely acute kidney injury, diabetic nephropathy, kidney stone disease and salt-sensitive hypertension. Furthermore, we will discuss the contribution of redox signaling in the pathogenesis of postmenopausal hypertension and preeclampsia.

Gender Differences in Hypertension

Hypertension is the leading risk factor for global mortality and morbidity and remains the major preventable cause of cardiovascular diseases. Gender differences in risk factors and awareness, treatment, and control of hypertension have been well established in humans. There are significant differences in epidemiology and clinical characteristic of hypertension between men and women. Moreover, gender differences are linked with several specific types of hypertension, including postmenopausal hypertension, white coat hypertension, masked hypertension, and hypertensive disorders of pregnancy. Gender differences have been implicated in the prevalence and determinants of hypertension and prehypertension whereas the control rate is similar between men and women taking antihypertensive medication. Importantly, distinct roles of the angiotensin-converting enzyme 2/Apelin signaling, sex hormone, endothelin-1, and sympathetic nervous activity contribute to sex differences in blood pressure control. This review summarizes gender differences in clinical features and determinants of hypertension and the underlying mechanisms responsible for hypertension.

The association between diabetes and age at the onset of menopause: a systematic review protocol

BACKGROUND

Age at the onset of menopause is the most important determinant of women's future health outcomes. While the basic mechanisms contributing to the onset of menopause are still not fully understood, age at menopause depends on a complex set of various factors. In this regard, the effects of diabetes (DM I/II) on the age at the onset of menopause have received little attention.

METHODS AND ANALYSIS

Electronic databases including PubMed/MEDLINE, Web of Science, Scopus, EMBASE, and Google Scholar will be searched for articles published during January 2000 to August 2018 and containing combinations of related MeSH terms, i.e., "age at menopause" and "diabetes." Additional studies will also be extracted from the reference lists of the selected papers, gray literature, and key journals in the field. A set of inclusion criteria will be defined, and all eligible observational studies will be included. Two reviewers will independently conduct the study selection, data extraction, and quality assessment of the selected studies. All cases of disagreement will be resolved through consensus. The methodological assessment of the primary studies will be performed based on the Newcastle-Ottawa Scale (NOS). In case of the availability of sufficient data, fixed or random effects models will be used to combine all data. Heterogeneity will be assessed by I 2 statistic and chi-square test. Stata V.11.1 will be used for data analysis (CRD42017080789).

ETHICS AND DISSEMINATION

This systematic review will not raise any ethical issues. Journal publication and conference presentations will facilitate the wide dissemination of the findings to relevant clinicians and researchers.

Should we calculate arterial stiffness gradient in middle-aged women with increased cardiovascular risk?

PURPOSE

The study was designed to evaluate clinical and laboratory determinants pulse wave velocity (PWV) ratio in women at the age of 50-65 years without overt cardiovascular disease but having elevated cardiovascular risk, such as hypertension, obesity, diabetes and hypercholesterolemia.

MATERIALS AND METHODS

We analyzed data from 1170 women enrolled in the national-wide primary prevention program. Univariate and multivariate linear regression analysis was used to establish independent risk factors in groups based on clinical data, laboratory values, and comorbidities. Arterial stiffness was evaluated using applanation tonometry technique (SphygmoCor). The PWV ratio was calculated by dividing cfPWV to crPWV.

RESULTS

In multivariate logistic regression analysis, age (OR = 1.109, p < .001), waist circumference (OR = 1.021, p = .001) and mean arterial pressure (OR = 1.031, p < .001) were found as independent clinical determinants of PWV ratio, while independent laboratory determinants were urine albumin to creatinine ratio (OR = 1.189, p = .010), triglycerides (OR = 1.161, p = .034), glucose (OR = 1.28, p = .001) and eGFR (OR = 0.998, p = .007). Diabetes (OR = 1.811, p = .029), hypertension (OR = 2.784, p = .042) and menopause (OR = 1.054, p = .018) were established as independent factors in comorbidities group. The analysis confirmed that PWV ratio (R² = 0.0667, p < .001), as well as carotid radial (R² = 0.0341, p < .001) and carotid femoral PWV (R² = 0.1752, p < .001) is affected by mean arterial blood pressure.

CONCLUSIONS

Age, abdominal obesity, blood pressure, triglycerides, glucose, kidney function parameters and menopause all are associated with PWV ratio. More importance to women with high cardiovascular risk should be given whilst screening and stratifying further progression of the disease.

Perinatal Taurine Supplementation Prevents Metabolic and Cardiovascular Effects of Maternal Diabetes in Adult Rat Offspring

This study tests the hypothesis that perinatal taurine supplementation prevents diabetes mellitus and hypertension in adult offspring of maternal diabetic rats. Female Wistar rats were fed normal rat chow and tap water with (Diabetes group) or without diabetic induction by intraperitoneal streptozotocin injection (Control group) before pregnancy. Then, they were supplemented with 3% taurine in water (Control+T and Diabetes+T groups) or water alone from conception to weaning. After weaning, both male and female offspring were fed normal rat chow and tap water throughout the study. Blood chemistry and cardiovascular parameters were studied in 16-week old rats. Body, heart, and kidney weights were not significantly different among the eight groups. Further, lipid profiles except triglyceride were not significantly different among male and female groups, while male Diabetes displayed increased fasting blood glucose, decreased plasma insulin, and increased plasma triglyceride compared to other groups. Compared to Control, mean arterial pressures significantly increased and baroreflex control of heart rate decreased in both male and female Diabetes, while heart rates significantly decreased in male but increased in female Diabetes group. Although perinatal taurine supplementation did not affect any measured parameters in Control groups, it abolished the adverse effects of maternal diabetes on fasting blood glucose, plasma insulin, lipid profiles, mean arterial pressure, heart rate, and baroreflex sensitivity in adult male and female offspring. The present study indicates that maternal diabetes mellitus induces metabolic and cardiovascular defects more in male than female adult offspring, and these adverse effects can be prevented by perinatal taurine supplementation.

Taurine Supplementation Ameliorates the Adverse Effects of Perinatal Taurine Depletion and High Sugar Intake on Cardiac Ischemia/Reperfusion Injury of Adult Female Rats

Perinatal taurine depletion followed by high sugar intake after weaning adversely affects myocardial and arterial pressure function following a myocardial ischemia and reperfusion (IR) insult in adult female rats. This study tests the hypothesis that taurine supplementation ameliorates this adverse effect. Female Sprague-Dawley rats were fed normal rat chow and drank water containing β-alanine from conception until weaning (taurine depletion, TD). After weaning, female offspring were fed normal rat chow and drank either water containing 5% glucose (TDG) or water alone (TDW). At 6-7 weeks of age, half the rats in each group were supplemented with taurine and 1 week later subjected to cardiac IR. Body weight, heart weight, plasma electrolytes, plasma creatinine, blood urea nitrogen, and hematocrit were not significantly different among the four groups. The mean arterial pressures significantly increased in all groups after IR, but values were not significantly different among the four groups. Heart rates were significantly increased after IR only in TDW group. Compared to TDW, TDG displayed increased plasma cardiac injury markers (creatinine kinase-MB, troponin T, and N-terminal prohormone brain natriuretic peptide), increased sympathetic activity, decreased parasympathetic activity, and decreased baroreflex sensitivity after IR. Taurine supplementation completely restored the baroreflex and autonomic dysfunction of TDG to TDW levels and partially decreased myocardial injury after cardiac IR. The present study indicates that in adult female rats, perinatal taurine depletion followed by high sugar intake after weaning exacerbates cardiac IR injury and arterial pressure dysregulation and these adverse effects can be partially prevented by taurine supplementation.

Perinatal Taurine Imbalance Followed by High Sugar Intake Alters the Effects of Estrogen on Renal Excretory Function in Adult Female Rats

This study tests the hypothesis that perinatal taurine imbalance impairs renal function in adult female rats via alterations in estrogen activity. Female Sprague-Dawley rats were fed normal rat chow and water containing 3% beta-alanine (TD), 3% taurine (TS) or water alone (C) from conception until weaning. Then, female offspring received normal rat chow and water with (CG, TDG, TSG) or without (CW, TDW, TSW) 5% glucose. At 7-8 weeks of age, renal function at rest and after acute saline load was tested in conscious, restrained female rats treated with non-selective estrogen receptor blocker tamoxifen for a week. Compared to control, TD or TS did not affect mean arterial pressure (MAP). Tamoxifen significantly increased resting MAP only in TDG compared to TDW groups. Although renal blood flow did not significantly differ among the groups, renal vascular resistance increased in TSG compared to CW, CG, and TSW groups. Glomerular filtration rate and water and sodium excretion were not significantly different among the groups. Compared to CW, saline load significantly depressed fractional water excretion in CG, TDW, TDG, and TSW, and fractional sodium excretion in CG, TDW, TDG, TSW, and the TSG groups. Potassium excretion was not significantly different among the corresponding groups. Fractional potassium excretion significantly increased in TDW compared to CG and in TSG compared to CG and TSW groups. These differences were abolished by tamoxifen treatment. These data indicate that in adult female rats, perinatal taurine imbalance, particularly followed by high sugar intake, alters renal function via an estrogenic mechanism.

Klotho and Postmenopausal Hormone Replacement Therapy in Women with Chronic Kidney Disease

Kidney function is highly susceptible to age-related changes, with chronic kidney disease (CKD) serving as an important cause of morbidity and mortality in older patients. The prevalence of CKD in Korea is higher among the elderly, relative to the general population, with the most significant increases seen following the onset of menopause. Under normal conditions, estrogen attenuates renal superoxide production and protects the kidney from oxidative damage. As estrogen levels are known to decrease by as much as 80% during menopause, this represents a significant risk for older women. Postmenopausal hormone replacement therapy (HRT) modulates the renin-angiotensin system, thereby reducing the progressive deterioration of renal function. Use of estrogen-based HRT has been shown to ameliorate renal function in postmenopausal women, and delay CKD progression. Renal expression of klotho, an important suppressor of aging, is markedly decreased in CKD patients, making it a promising candidate for use as a prognostic biomarker in CKD. Here, we review the key links between renal function, sex, age, and estrogen levels during menopause, and discuss the use of postmenopausal HRT in CKD attenuation.

Acute effects of different resistance training loads on cardiac autonomic modulation in hypertensive postmenopausal women

BACKGROUND

Individuals with arterial hypertension often have an autonomic nervous system (ANS) imbalance with predominance of sympathetic ANS. This predominance can lead to injury of several organs affecting its functioning. There is evidence that performing high intensity resistance training (RT) with heavier loads and a lower number of repetitions results in lower cardiovascular stress when compared with lighter loads and a higher number of repetitions. However, the effects of different protocols of RT in autonomic modulation are not known. Therefore, the aim of the study was to analyze and compare the effects of different protocols of high intensity of effort RT on autonomic cardiac modulation of hypertensive women.

METHODS

A randomized crossover design clinical trial was conducted with 15 postmenopausal hypertensive women who underwent a control session and two high intensity RT protocols involving 6 and 15 repetition maximum (RM). Heart rate variability (HRV), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and double product (DP) were collected pre, immediately post, 1 h post, and 24 h post each protocol. Repeated-measures ANOVA were used.

RESULTS

SBP was higher for 6RM than control immediately after session (p < 0.05). There were no differences for DBP among protocols (p ≥ 0.05). HR was higher for 15RM than 6RM and control immediately after and 1 h after session (p ≤ 0.05). DP values for 15RM were significantly higher than 6RM and control immediately after the session and remained higher than control 1 h after session (p ≤ 0.05). The indices that compose HRV (rMSSD) were lower after 15RM than 6RM and control (p ≥ 0.05). The parameters of parasympathetic activity (HF) were decreased and sympathetic (LF) activity was increased for 15RM when compared to the 6RM and control session immediately after the exercise session (p ≤ 0.05).

CONCLUSION

Performing high intensity RT with lower loads and a higher number of repetitions seems to promote acute increases in sympathetic ANS activity, which may be related to cardiovascular stress. On the other hand, heavier load and lower repetition RT did not significantly impact upon autonomic modulation when compared to a control session.

Associations of Blood Pressure with the Factors among Adults in Jilin Province: A Cross-Sectional Study Using Quantile Regression Analysis

Hypertension has become a major public health challenge. However, numerous research results reported in the literature focus primarily on risk factors of hypertension, little is known about how the whole continuum of blood pressure (BP) is associated with risk factors of hypertension. This study aims to reveal quantile-specific associations of BP with its risk factors. A cross-sectional survey based on a sample of 23,050 adults aged 18 to 79 years was conducted in Jilin Province in 2012, and some subjects were excluded due to missing values in BP or having BP control according to the purpose of this study. Quantile regression (QR) was employed to investigate the associations between systolic/diastolic blood pressure (SBP/DBP) and the risk factors. The SBP and DBP in males presented statistically higher than females (P < 0.001). High-salt diet for males manifested a slightly increasing positive association with higher SBP only for high quantiles (≥70), but with a higher DBP for middle part of the quantiles (30~75), compared with bland diet. High-salt diet, drinking and high-density lipoprotein cholesterol (HDL-C) were positively associated with BP measures in males. And the coefficient of total cholesterol (TC) in QR increased with BP in females who used to live in town.

Ovariectomy uncovers purinergic receptor activation of endothelin-dependent natriuresis

We recently reported that natriuresis produced by renal medullary salt loading is dependent on endothelin (ET)-1 and purinergic (P2) receptors in male rats. Because sex differences in ET-1 and P2 signaling have been reported, we decided to test whether ovarian sex hormones regulate renal medullary ET-1 and P2-dependent natriuresis. The effect of medullary NaCl loading on Na⁺ excretion was determined in intact and ovariectomized (OVX) female Sprague-Dawley rats with and without ET-1 or P2 receptor antagonism. Isosmotic saline (284 mosmol/kgH₂O) was infused in the renal medullary interstitium of anesthetized rats during a baseline urine collection period, followed by isosmotic or hyperosmotic saline (1,800 mosmol/kgH₂O) infusion. Medullary NaCl loading significantly enhanced Na⁺ excretion in intact and OVX female rats. ET_A+B or P2 receptor blockade did not attenuate the natriuretic effect of medullary NaCl loading in intact females, whereas ET_A+B or P2 receptor blockade attenuated the natriuretic response to NaCl loading in OVX rats. Activation of medullary P2Y₂ and P2Y₄ receptors by UTP infusion had no significant effect in intact females but enhanced Na⁺ excretion in OVX rats. Combined ET_A+B receptor blockade significantly inhibited the natriuretic response to UTP observed in OVX rats. These data demonstrate that medullary NaCl loading induces ET-1 and P2-independent natriuresis in intact females. In OVX, activation of medullary P2 receptors promotes ET-dependent natriuresis, suggesting that ovarian hormones may regulate the interplay between the renal ET-1 and P2 signaling systems to facilitate Na⁺ excretion.

Consumption of nattokinase is associated with reduced blood pressure and von Willebrand factor, a cardiovascular risk marker: results from a randomized, double-blind, placebo-controlled, multicenter North American clinical trial

OBJECTIVE

The objective of this study is to evaluate the effects of consumption of nattokinase on hypertension in a North American hypertensive population with associated genetic, dietary, and lifestyle factors. This is in extension of, and contrast to, previous studies on Asian populations.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled, parallel-arm clinical study was performed to evaluate nattokinase (NSK-SD), a fermented soy extract nattō from which vitamin K2 has been removed. Based on the results from previous studies on Asian populations, 79 subjects were enrolled upon screening for elevated blood pressure (BP; systolic BP ≥130 or diastolic BP ≥90 mmHg) who consumed placebo or 100 mg nattokinase/d for the 8-week study duration. Blood collections were performed at baseline and 8 weeks for testing plasma renin activity, von Willebrand factor (vWF), and platelet factor-4. Seventy-four people completed the study with good compliance.

RESULTS

Consumption of nattokinase was associated with a reduction in both systolic and diastolic BP. The reduction in systolic BP was seen for both sexes but was more robust in males consuming nattokinase. The average reduction in diastolic BP in the nattokinase group from 87 mmHg to 84 mmHg was statistically significant when compared to that in the group consuming placebo, where the average diastolic BP remained constant at 87 mmHg (P<0.05), and reached a high level of significance for males consuming nattokinase, where the average diastolic BP dropped from 86 mmHg to 81 mmHg (P<0.006). A decrease in vWF was seen in the female population consuming nattokinase (P<0.1). In the subpopulation with low plasma renin activity levels at baseline (<0.29 ng/mL/h), an increase was seen for 66% of the people after 8-week consumption of nattokinase (P<0.1), in contrast to only 8% in the placebo group.

CONCLUSION

The data suggest that nattokinase consumption in a North American population is associated with beneficial changes to BP in a hypertensive population, indicating sex-specific mechanisms of action of nattokinase's effect on vWF and hypertension.

Hypertension and age at onset of natural menopause in Korean postmenopausal women: Results from the Korea National Health and Nutrition Examination Survey (2008-2013)

OBJECTIVES

Menopause is a natural phenomenon of aging, although the timing and management of menopause can significantly affect a woman's quality of life. It is therefore important to identify measures to ensure a healthy menopause. We set out to investigate the association between hypertension and early menopause in Korean women.

STUDY DESIGN

This cross-sectional study was based on 2008-2013 data from the Korea National Health and Nutrition Examination Survey (KNHANES). Of the 53,829 participants surveyed, 13,584 women were selected. We analyzed the contents of the health interview, health examination, and nutrition survey.

MAIN OUTCOME MEASURE

The main outcome was defined based on hazard ratios (HR) to identify the effects of hypertension on age at onset of menopause.

RESULTS

Among postmenopausal women (n=6650), the mean age at onset of menopause was 50.4 years. Premenopausal hypertension was statistically significantly associated with age at menopause, oral contraceptive usage, household income, education level, occupation, marital status and smoking and drinking habits. With lower age at diagnosis of hypertension, HRs for menopause tended to be higher, and hypertension diagnosed before age 40 years conferred a statistically significantly higher HR (Model 1, HR=2.32, 95% CI=1.87-2.88; Model 2, HR=2.31, 95% CI=1.86-2.86; Model 3, HR=2.23, 95% CI=1.80-2.77; Model 4, HR=2.00, 95% CI=1.52-2.63).

CONCLUSION

Premature menopause is strongly associated with lifestyle factors, in combination with incomplete management of chronic diseases. Our findings support the hypothesis that younger age at diagnosis of hypertension is associated with younger age at onset of menopause in Korean women.

Postmenopausal Women Have Higher HDL and Decreased Incidence of Low HDL than Premenopausal Women with Metabolic Syndrome

It is well known that plasma lipids, waist circumference (WC) and blood pressure (BP) increase following menopause. In addition, there is a perceived notion that plasma high-density lipoprotein-cholesterol (HDL-C) concentrations also decrease in postmenopausal women. In this cross-sectional study, we evaluated plasma lipids, fasting glucose, anthropometrics and BP in 88 post and 100 pre-menopausal women diagnosed with metabolic syndrome. No differences were observed in plasma low-density lipoprotein-cholesterol cholesterol, triglycerides, fasting glucose or systolic and diastolic BP between groups. However, plasma HDL-C was higher (p < 0.01) in postmenopausal women and the percentage of women who had low HDL (<50 mg/dL) was higher (p < 0.01) among premenopausal women. In addition, negative correlations were found between WC and HDL-C (r = -0.148, p < 0.05) and BMI and HDL-C (r = -0.258, p < 0.01) for all subjects indicating that increases in weight and abdominal fat have a deleterious effect on plasma HDL-C. Interestingly, there was a positive correlation between age and plasma HDL-C (r = 0.237 p < 0.01). The results from this study suggest that although HDL is decreased by visceral fat and overall weight, low HDL is not a main characteristic of metabolic syndrome in postmenopausal women. Further, HDL appears to increase, not decrease, with age.

Occupational Disparities in the Association between Self-Reported Salt-Eating Habit and Hypertension in Older Adults in Xiamen, China

Blood pressure responses to sodium intake are heterogeneous among populations. Few studies have assessed occupational disparities in the association between sodium intake and hypertension in older people. We used cross-sectional data from 14,292 participants aged 60 years or older in Xiamen, China, in 2013. Self-reported salt-eating habit was examined with three levels: low, medium, and high. The main lifetime occupation was classified into indoor laborer and outdoor laborer. Multivariable logistic regression was used to examine associations of hypertension with self-reported salt-eating habit, main lifetime occupation, and their interactions by adjusting for some covariates, with further stratification by sex. Overall, 13,738 participants had complete data, of whom 30.22% had hypertension. The prevalence of hypertension was 31.57%, 28.63%, and 31.97% in participants who reported to have low, medium, and high salt-eating habit, respectively. Outdoor laborers presented significantly lower prevalence of hypertension than indoor laborers (26.04% vs. 34.26%, p < 0.001). Indoor laborers with high salt-eating habit had the greatest odds of hypertension (OR = 1.32, 95% CI [1.09–1.59]). An increased trend of odds in eating habit as salt-heavier was presented in indoor laborers (p-trend = 0.048), especially for women (p-trend = 0.001). No clear trend presented in men. Conclusively, sex-specific occupational disparities exist in the association between self-reported salt-eating habit and hypertension in older individuals. Overlooking the potential moderating role of sex and occupation might affect the relationship between sodium intake and hypertension.

Ovarian hormones modulate endothelin A and B receptor expression

AIMS

The study aims to determine the modulatory roles of ovarian hormones, estrogen (E2) and progesterone (P), on the expression of endothelin A (ETA) and B (ETB) receptors in lung, liver and kidney tissues.

MAIN METHODS

Female Sprague-Dawley rats were subjected to bilateral ovariectomy and divided into four groups ovariectomized (OVX), OVX+E2, OVX+P, and OVX+E2+P. A separate group of rats underwent sham surgery and served as a control. Three weeks after OVX or sham surgery, tissues from lungs, liver, renal cortex, and inner medulla were collected, snap-frozen, and kept at -80°C for assessment of ETA and ETB receptor expression using real-time PCR.

KEY FINDINGS

E2-treated OVX animals had significantly lower expression of ETA receptors in the lungs, compared to OVX rats. Pulmonary ETB receptor mRNA was not measurably affected by any of the interventions. Hepatic ETA and ETB were significantly increased in OVX+E2+P rats, compared to sham rats. Renal inner medullary ETA and ETB receptor expressions were significantly elevated in OVX compared to sham, an effect that was prevented by co-supplementation of OVX with E2 and P. Additionally, both ETA and ETB receptor expression in the renal cortex were significantly attenuated by ovariectomy, and this reduction was not evident in OVX+E2 rats.

SIGNIFICANCE

These data suggest that ovarian hormones regulate ET receptor expression and may contribute to sex differences in cardiovascular and renal health.

Sex, the brain and hypertension: brain oestrogen receptors and high blood pressure risk factors

Hypertension is a major contributor to worldwide morbidity and mortality rates related to cardiovascular disease. There are important sex differences in the onset and rate of hypertension in humans. Compared with age-matched men, premenopausal women are less likely to develop hypertension. However, after age 60, the incidence of hypertension increases in women and even surpasses that seen in older men. It is thought that changes in levels of circulating ovarian hormones as women age may be involved in the increase in hypertension in older women. One of the key mechanisms involved in the development of hypertension in both men and women is an increase in sympathetic nerve activity (SNA). Brain regions important for the regulation of SNA, such as the subfornical organ, the paraventricular nucleus and the rostral ventral lateral medulla, also express specific subtypes of oestrogen receptors. Each of these brain regions has also been implicated in mechanisms underlying risk factors for hypertension such as obesity, stress and inflammation. The present review brings together evidence that links actions of oestrogen at these receptors to modulate some of the common brain mechanisms involved in the ability of hypertensive risk factors to increase SNA and blood pressure. Understanding the mechanisms by which oestrogen acts at key sites in the brain for the regulation of SNA is important for the development of novel, sex-specific therapies for treating hypertension.

Effects of aerobic exercise on blood pressure and lipids in overweight hypertensive postmenopausal women

Menopause may increase risk of hypertension and abnormal lipid profile. The aim of the study was to examine the effects of morning and afternoon aerobic exercises on hypertension and lipids in overweight hypertensive postmenopausal women. Forty five women aged from 49 to 60 years were randomly assigned into three groups. Group (A) 15 patients received medicine, (B) 15 patients performed morning aerobic exercises and received medicine, and group (C) 15 patients performed afternoon aerobic exercises and received medicine. Blood pressure measurement and lipid profile tests were performed before and after the study. The results showed that there was a statistical significant difference among all groups in systolic and diastolic blood pressure, favoring group C. Also there was a statistical significant difference among all groups in lipid levels, favoring group C. Therefore, it can be concluded that morning aerobic exercises were more effective in reducing the blood pressure and lipids than afternoon exercises in overweight hypertensive postmenopausal women.