Postmenopausal hypertension, abdominal obesity, apolipoprotein and insulin resistance

The association of menopause with cardiometabolic disease risk factors in low- and middle-income countries: a systematic review and meta-analyses

IMPORTANCE

Menopause is an integral part of women's health, and studies in high-income countries have shown an increase in cardiometabolic disease (CMD) risk factors in postmenopausal compared with premenopausal women. However, to date, no study has combined and assessed such studies across low- and middle-income countries. This would better inform early monitoring and intervention strategies for reducing CMD risk factor levels in midlife women in these regions.

OBJECTIVE

This study aimed to evaluate evidence from the literature on differences in CMD risk factors between premenopausal and postmenopausal midlife women living in low- and middle-income countries.

EVIDENCE REVIEW

A systematic review with meta-analysis of original articles of all study designs from the databases PubMed, PubMed Central, Scopus, and ISI Web of Science was conducted from conception until April 24, 2023. Studies that met the inclusion criteria were included in the analysis. Quality assessment of the articles was done using the Newcastle-Ottawa Scale, adapted for each study design. The study protocol was registered with the International Prospective Register of Systematic Reviews and adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. For the meta-analysis, fixed-effects models were used to pool the odds ratios (OR), as measures of association.

FINDINGS

Our search identified 4,849 relevant articles: 44 for the systematic review and 16 for the meta-analysis, in accordance with our inclusion criteria. Compared with premenopausal women, the postmenopausal stage was associated with metabolic syndrome (OR, 1.18 [95% CI, 1.11-1.27]), high waist-to-hip ratio (OR, 1.22 [95% CI, 1.12-1.32]), hypertension (OR, 1.10 [95% CI, 1.04-1.16]), elevated triglycerides (OR, 1.16 [95% CI, 1.11-1.21]), and elevated plasma glucose (OR, 1.21 [95% CI, 1.15-1.28]).

CONCLUSIONS AND RELEVANCE

This study confirmed that CMD risk factors are present at higher levels in postmenopausal than premenopausal women. This demonstrates an urgent need for public health policies that focus on early monitoring and interventions targeted at reducing CMD risk and related adverse outcomes in midlife women in these nations.

Additive interactions between obesity and insulin resistance on hypertension in a Chinese rural population

BACKGROUND

Adiposity and insulin resistance (IR) are closely associated with hypertension; however, the role of interactions between obesity phenotypes and IR in hypertension is unclear. This study aimed to evaluate the interactions of body mass index (BMI), waist circumference (WC), and body fat percentage (BF%) with IR on hypertension risk.

METHODS

We analyzed data from 4888 participants (mean age 57 years, 41.2% men) in the China Northwest Natural Population Cohort, Ningxia Project. BMI, WC, and BF% were determined using bioelectrical impedance analysis devices. IR was estimated using a homeostasis model assessment index (HOMA-IR). Multivariable-adjusted logistic regression was used to evaluate the association between HOMA-IR and hypertension risk. We calculated the relative excess risk and attributable proportion with their 95% confidence intervals (CIs) to assess whether adiposity phenotypes modified the effect of HOMA-IR on hypertension risk.

RESULTS

The crude prevalence of hypertension was 52.2%. The multivariable-adjusted odds ratio of HOMA-IR was 1.80 (95% CI: 1.23-2.65) for the risk of hypertension in the highest versus the lowest quartiles, but this association became marginal in models further adjusting for BMI, WC, and BF% (P for trend = 0.056). Relative excess risk and attributable proportion for interaction between high HOMA-IR and high BF% were 0.32 (0.04-0.59) and 0.33 (0.06-0.60), respectively. Additionally, high truncal and leg BF% and high HOMA-IR accounted for the hypertension risk in women, but not in men. We did not observe any significant interactions between BMI or WC and HOMA-IR on hypertension.

CONCLUSION

BF% modified the association between IR and increased risk of hypertension in women with high truncal and leg BF%, but not in men.

Role of gender in explaining metabolic syndrome risk factors in an Iranian rural population using structural equation modelling

Many factors can lead to an increase in the prevalence of metabolic syndrome (MetS) in different populations. Using an advanced structural equation model (SEM), this study is aimed to determine the most important risk factors of MetS, as a continuous latent variable, using a large number of males and females. We also aimed to evaluate the interrelations among the associated factors involved in the development of MetS. This study used data derived from the Fasa PERSIAN cohort study, a branch of the PERSIAN cohort study, for participants aged 35 to 70 years with 10,138 males and females. SEM was used to evaluate the direct and indirect effects, as well as gender effects of influencing factors. Results from the SEM showed that in females most changes in MetS are described by waist circumference (WC), followed by hypertension (HP) and triglyceride (TG), while in males most changes in MetS are described by WC, followed by TG then fasting blood glucose (FBG). Results from the SEM confirmed the gender effects of social status on MetS, mediated by sleep and controlled by age, BMI, ethnicity and physical activity. This study also shows that the integration of TG and WC within genders could be useful as a screening criterion for MetS in our study population.

Exploration of plasma adiponectin, leptin, and COMT genotype on blood pressure among women who are post-menopause

Research suggests that adiponectin, leptin, and genetic polymorphisms such as catechol-O-methyltransferase (COMT) genotype may play an integral role in blood pressure status and thereby cardiovascular health. This is an area especially important for women who are post-menopause; however, the current literature investigating these associations is limited. This study was a cross-sectional secondary analysis of baseline data (N 237) from the Minnesota Green Tea Trial (MGTT). The current study explored the relationships between plasma adiponectin, leptin, and COMT genotype on blood pressure measures. Plasma adiponectin and leptin were obtained after an overnight fast of at least 10 h and were measured by the radioimmunoassay method. The relationships were analysed using multiple linear regression after adjusting for potential confounders. Effect modifications by age, body mass index (BMI) category, blood pressure category, antihypertensive medication use, and COMT genotype were also investigated. The majority of participants were non-Hispanic (97⋅9 %) and Caucasian (94⋅9 %). Mean (sd) age and BMI were 60⋅7 (5⋅0) years and 28⋅2 (2⋅9) kg/m2, respectively. After adjustment for confounding variables, neither plasma adiponectin, plasma leptin nor COMT genotype was associated with systolic or diastolic blood pressure measures. The results of stratified analyses also did not reveal any significant interactions or associations. Based on the findings of this study, which utilised more rigorous statistical methods than previous research, neither adiponectin, leptin nor COMT genotype play a role in blood pressure measures in women who are post-menopause.

Genetics of Cholesterol-Related Genes in Metabolic Syndrome: A Review of Current Evidence

Metabolic syndrome (MetS) refers to a cluster of metabolic dysregulations, which include insulin resistance, obesity, atherogenic dyslipidemia and hypertension. The complex pathogenesis of MetS encompasses the interplay between environmental and genetic factors. Environmental factors such as excessive nutrients and sedentary lifestyle are modifiable and could be improved by lifestyle modification. However, genetic susceptibility to MetS, a non-modifiable factor, has attracted the attention of researchers, which could act as the basis for future diagnosis, prognosis, and therapy for MetS. Several cholesterol-related genes associated with each characteristic of MetS have been identified, such as apolipoprotein, lipoprotein lipase (LPL), cholesteryl ester transfer protein (CETP) and adiponectin. This review aims to summarize the genetic information of cholesterol-related genes in MetS, which may potentially serve as biomarkers for early prevention and management of MetS.

The correlation of the fecal microbiome with the biochemical profile during menopause: a Brazilian cohort study

BACKGROUND

Hormonal, biochemical, and metabolic changes after menopause may alter the quality of life of women, leading to vasomotor, psychological, and genitourinary symptoms, and changes in their gut microbiota, which regulates estrogen levels through the estroboloma. Fecal samples were used to investigate the changes in the gut microbiota during aging and hormonal changes in women. A balanced gut microbiota has been associated with health or disease conditions and remains poorly understood after menopause. This study identified the fecal microbiota, and their association with biochemical and hormonal parameters of a cohort of women in the climacteric in the city of Ouro Preto-MG, Brazil.

METHODS

A total of 102 women aged 40 to 65 years old were recruited and distributed into three groups according to the STRAW criteria for reproductive stage: reproductive (n = 18), premenopausal (n = 26), and postmenopausal (n = 58). Blood samples were collected to measure their serum biochemical and hormone levels, and the participants answered a questionnaire. The gut microbiota was analyzed from fecal samples by qPCR using the genera Bifidobacterium, Bacteroides, Lactobacillus, and Clostridium.

RESULTS

The following parameters showed differences among the groups: total cholesterol, triglycerides, VLDL, ApoB, urea, calcium, uric acid, and alkaline phosphatase (p < 0.05). qPCR revealed the genus Clostridium to be the most abundant in all three groups. In the reproductive age group, the significant correlations were: Bacteroides with glucose (r = -0.573 p = 0.0129), and SDHEA (r = -0.583 p = 0.0111). For the premenopausal group, they were: Bifidobacteria with total cholesterol (r = 0.396 p = 0.0451), LDL (r = 0.393 p = 0.0468), ApoB (r = 0.411 p = 0.0368); Lactobacillus and calcium (r = 0.443 p = 0.0232), ALP (r = 0.543 p = 0.0041), LPa (r =-0.442 p = 0.02336); and Bacteroides and urea (r =-0.461 p = 0.0176). In the postmenopausal group, they were Bifidobacterium and ALP (r =-0.315 p = 0.0159), Lactobacillus and urea (r =-0.276 p = 0.0356), and Clostridium and beta estradiol (r =-0.355 p = 0.0062).

CONCLUSION

In conclusion, the hormonal and metabolic changes during menopause in the population studied were accompanied by a significant change in the fecal microbiota, especially of the genus Clostridium.

Apolipoprotein B Displays Superior Predictive Value Than Other Lipids for Long-Term Prognosis in Coronary Atherosclerosis Patients and Particular Subpopulations: A Retrospective Study

PURPOSE

Accumulating evidence that apolipoprotein B (apoB) plays a critical role in predicting coronary heart disease (CHD) and future outcomes. The 2019 European Society of Cardiology/European Atherosclerosis Society guidelines suggest that apoB can be an alternative to non-HDL-C or LDL-C in patients with high triglyceride levels, diabetes, obesity, metabolic syndrome, or very low LDL-C levels. This study explores whether apoB can also serve as predictive value for long-term major adverse cardiovascular events (MACEs) in normal people and specific coronary atherosclerosis patients.

METHODS

A total of 826 patients were followed up over 10 years, and the risk factors for MACEs were retrospectively analyzed in patients with CHD and particular subpopulations. All statistical analyses were performed in R software. Cox regressions were performed to assess independent risk factors of long-term MACEs in the atherosclerosis group and CHD subgroups. Kaplan-Meier survival curves were used to evaluate the survival rate for patients in different apoB quartiles, and receiver-operating characteristic curves were used to compare apoB and other lipids in predicting the presence of long-term MACE.

FINDINGS

apoB could be a "risk-enhancing factor" in patients with coronary atherosclerosis disease, whereas in the Normal population, LDL-C still acted as a major risk factor for predicting MACEs. apoB was a good risk predictor for long-term cardiovascular events in coronary atherosclerosis (AS) patients, including the AS group and CHD subpopulations (including CHD + triglyceride ≥2.3 mmol/L, CHD + diabetes mellitus, CHD + body mass index ≥25 kg/m², or CHD + metabolic syndrome). In patients with CHD whose condition was complicated with diabetes, obesity, and metabolic syndrome, apoB performed better than other lipids in predicting the presence of myocardial infarction, hospitalization due to angina, and cardiac death. Despite achieving optimal LDL-C or non-HDL-C levels, patients with CHD are still at risk of worse survival if they are unable to reach a low apoB level (lower cut points such as 65 mg/dL).

IMPLICATIONS

More attention should be paid to special populations with residual elevations of atherogenic particle numbers, and greater focus should be placed on lowering baseline apoB to achieve long-term benefits. However, given that this was an observational study, the association of baseline apoB level and long-term MACEs only was evaluated; it is unclear whether the emergence of MACEs would be influenced by the dynamic changes of apoB. Because this was a retrospective and observational analysis, bias in data analysis was unavoidable; thus, the results cannot be used to generalize implications to broader patient populations, and more large-scale clinical trials are required to verify these findings. (Clin Ther. 2022;44:XXX-XXX) © 2022 Elsevier HS Journals, Inc.

Association between body fat percentage and H-type hypertension in postmenopausal women

Background

Previous studies have explored the relationship between body fat percentage (BFP) and hypertension or homocysteine. However, evidence on the constancy of the association remains inconclusive in postmenopausal women. The aim of this study was to investigate the association between BFP and H-type hypertension in postmenopausal women.

Methods

This cross-sectional study included 1,597 eligible female patients with hypertension. Homocysteine levels ≥10 mmol/L were defined as H-type hypertension. BFP was calculated by measuring patients' physical parameters. Subjects were divided into 4 groups according to quartiles of BFP (Q1: 33.4% or lower, Q2: 33.4–36.1%, Q3: 36.1–39.1%, Q4: >39.1%). We used restricted cubic spline regression models and logistic regression analysis to assess the relationship between BFP and H-type hypertension. Additional subgroup analysis was performed for this study.

Results

Among 1,597 hypertensive patients, 955 (59.8%) participants had H-type hypertension. There were significant differences between the two groups in age, BMI, educational background, marital status, exercise status, drinking history, WC, TG, LDL, Scr, BUN, and eGFR (P < 0.05). The prevalence of H-type hypertension in the Q1 to Q4 groups was 24.9, 25.1, 24.9, and 25.1%, respectively. After adjusting for relevant factors, we found that the risk of H-type hypertension in the Q4 group had a significantly higher than the Q1 group (OR = 3.2, 95% CI: 1.3–7.5).

Conclusion

BFP was positively associated with the risk of H-type hypertension in postmenopausal women. Postmenopausal women should control body fat to prevent hypertension.

A review of menopause nomenclature

Menopause nomenclature varies in the scholarly literature making synthesis and interpretation of research findings difficult. Therefore, the present study aimed to review and discuss critical developments in menopause nomenclature; determine the level of heterogeneity amongst menopause definitions and compare them with the Stages of Reproductive Aging Workshop criteria. Definitions/criteria used to characterise premenopausal and postmenopausal status were extracted from 210 studies and 128 of these studies were included in the final analyses. The main findings were that 39.84% of included studies were consistent with STRAW classification of premenopause, whereas 70.31% were consistent with STRAW classification of postmenopause. Surprisingly, major inconsistencies relating to premenopause definition were due to a total lack of reporting of any definitions/criteria for premenopause (39.84% of studies). In contrast, only 20.31% did not report definitions/criteria for postmenopause. The present findings indicate that there is a significant amount of heterogeneity associated with the definition of premenopause, compared with postmenopause. We propose three key suggestions/recommendations, which can be distilled from these findings. Firstly, premenopause should be transparently operationalised and reported. Secondly, as a minimum requirement, regular menstruation should be defined as the number of menstrual cycles in a period of at least 3 months. Finally, the utility of introducing normative age-ranges as supplementary criterion for defining stages of reproductive ageing should be considered. The use of consistent terminology in research will enhance our capacity to compare results from different studies and more effectively investigate issues related to women's health and ageing.

Association between body mass index, waist circumference, and age at natural menopause: a population-based cohort study in Chinese women

The purpose of the study was to investigate whether premenopausal body mass index (BMI) and waist circumference (WC) influence age at menopause. A total of 2116 women aged 35-64 years from two communities of the CMCS Beijing cohort were recruited in 1992 and followed up to 2018. Of 1439 premenopausal women at baseline, 6 women data were missing. Finally, 1433 women were included for analysis. Overweight was defined as BMI 24-27.99 kg/m². Central obesity was defined as WC ≥80 cm. Age at menopause was categorized as <45 years, 45-49 years, 50-51 years (reference), and >51 years. Multinomial logistic regression models were used to estimate relative odds ratios (RORs) and 95% confidence intervals (CIs). Compared to women with normal weight and normal WC, overweight women with normal WC had higher risk of menopause at >51 years (ROR 1.64, 95% CI 1.10-2.45; P = .01); and overweight women with central obesity had higher risk of menopause at not only >51 years (ROR 1.82, 95% CI 1.13-2.93; P = .01) but also <45 years (ROR 3.13, 95% CI 1.20-8.43; P = .02) and 45-49 years (ROR 2.76, 95% CI 1.71-4.46; P < .001). When overweight women combine with central obesity, the risk of early menopause will increase in some of them.

[Does Apolipoprotein B Level in Early Pregnancy Predict Excessive Gestational Weight Gain and Adverse Pregnancy Outcome?]

INTRODUCTION

Excessive maternal gestational weight gain (GWG) is a risk factor for maternal and fetal complications. The lipid profile changes physiologically during pregnancy. Weight gain can affect lipid metabolism. The hypothesis of the study was that apoB levels early in pregnancy are associated with excessive GWG and predictive for adverse outcomes.

METHODS

Out of 547 patients there were 95 women with inadequate GWG, 171 with adequate GWG, and 281 with excessive GWG. Out of 581 patients there were 14 patients with pregnancy-induced hypertonus/pre-eclampsia, 67 with small-for-gestational-age (SGA) infants, and 7 with fetal growth restriction (FGR). ApoB levels were measured by ELISA.

RESULTS

There was no significant difference in apoB levels between the different GWG groups. We found significantly higher levels of apoB in overweight and obese patients compared to those with normal BMI. Smoking was correlated with higher apoB levels. There were no differences either between women with PIH/PE and normotensive women or between SGA/IUGR and pregnancies without. Women with pre-existing hypertension showed significantly higher apoB levels than the control group.

CONCLUSIONS

ApoB cannot be used as a marker for identifying the risk of excessive GWG or adverse pregnancy outcomes early in pregnancy. However, it may be involved in the pathophysiology of adverse pregnancy outcomes in high-risk patients.

Independent and combined effects of triglyceride-glucose index on prehypertension risk: a cross-sectional survey in China

Triglyceride-glucose (TyG) index is considered a simple and feasible indicator of insulin resistance (IR). This study aims to delve into the association and interaction of TyG index on the risk of prehypertension in Chinese adults. A community based cross-sectional survey conducted in Chinese population. Eligible participants were recruited, and questionnaire survey, anthropometric tests, and blood samples collection were performed. TyG index was obtained as ln [fasting TG(mg/dl) × FPG(mg/dl)/2]. Logistic regression model and the area under the receiver-operating characteristics (ROC) curves (AUC) were analyzed. Interaction analysis was conducted by calculating relative excess risk for interaction (RERI), attributable proportion for interaction (AP) as well as synergy index (SI). A total of 3115 recruited participants (1307 males and 1808 females) were aged 60.82 years on average. The prevalence of prehypertension reached 36.4% on the whole, 37.6% in male and 35.5% in female, respectively. The results of multivariable logistic regression model suggested that the adjusted OR for prehypertension was upregulated across TyG index quartiles, up to 2.06 (95% CI:1.53-2.77) for quartiles 4 versus quartiles 1. Furthermore, TyG index outperformed FPG (Z = 2.15, p = 0.032) and TG (Z = 6.10, p < 0.001) in discriminating prehypertension risk. Besides, TyG index with abdominal obesity (RERI:1.53, 95% CI:0.39-2.67; AP: 0.37, 95% CI: 0.16-0.59; SI:1.96, 95% CI:1.15-3.34) displayed a noticeable interaction on risk of prehypertension. Our study indicated that a higher TyG index rose the risk of prehypertension independently and synergistically with abdominal obesity in Chinese adults. Furthermore, it exhibited a higher predictability compared with conventional indices.

Predictors of incident hypertension in healthy non-diabetic postmenopausal women with normal renal function

Introduction: We aimed to investigate the incidence of hypertension and to identify potential risk factors in healthy, non-diabetic recently postmenopausal Greek women with normal renal function.Patients and methods: This retrospective cohort study evaluated 141 recently postmenopausal women at baseline and annually thereafter (follow-up time: 1 to 8 years). Blood samples were obtained, and ultrasound evaluations were performed at baseline. A detailed medical history, anthropometric parameters, blood pressure and cardiovascular risk factors were recorded for every woman at each visit. Incident hypertension was defined as the first occurrence of office systolic or diastolic blood pressure, measured at 2 different visits within 2 months or history of initiation of antihypertensive medication.Results: Incident hypertension was diagnosed in 30 out of 141 women (21.3%). The median time to incident hypertension was 3.5 years. Adiposity, elevated cholesterol and triglyceride levels, insulin resistance and parity were positively associated with incident hypertension. In multivariate analysis, however, obesity and insulin resistance were the only statistically significant variables associated with more than 3-fold and 2-fold respectively increased risk of incident hypertension (HOMA-IR, O.R = 1.988, p-value =.043; obesity, O.R = 3.746, p-value =.019).Conclusion: A significant proportion of women entering the menopause present incident hypertension and this is mostly associated with obesity and insulin resistance.

Fat mass changes during menopause: a metaanalysis

OBJECTIVE

Data: Fat mass has been shown to increase in aging women; however, the extent to which menopausal status mediates these changes remains unclear. The purpose of this review was to determine (1) how fat mass differs in quantity and distribution between premenopausal and postmenopausal women, (2) whether and how age and/or menopausal status moderates any observed differences, and (3) which type of fat mass measure is best suited to the detection of differences in fat mass between groups.

STUDY

This review with metaanalyses is reported according to Metaanalysis of Observational Studies in Epidemiology guidelines.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies (published up to May 2018) were identified via PubMed to provide fat mass measures in premenopausal and postmenopausal women. We included 201 cross-sectional studies in the metaanalysis, which provided a combined sample size of 1,049,919 individuals and consisted of 478,734 premenopausal women and 571,185 postmenopausal women. Eleven longitudinal studies were included in the metaanalyses, which provided a combined sample size of 2472 women who were premenopausal at baseline and postmenopausal at follow up.

RESULTS

The main findings of this review were that fat mass significantly increased between premenopausal and postmenopausal women across most measures, which included body mass index (1.14 kg/m²; 95% confidence interval, 0.95-1.32 kg/m²), bodyweight (1 kg; 95% confidence interval, 0.44-1.57 kg), body fat percentage (2.88%; 95% confidence interval, 2.13-3.63%), waist circumference (4.63 cm; 95% confidence interval, 3.90-5.35 cm), hip circumference (2.01 cm; 95% confidence interval, 1.36-2.65 cm), waist-hip ratio (0.04; 95% confidence interval, 0.03-0.05), visceral fat (26.90 cm²; 95% confidence interval, 13.12-40.68), and trunk fat percentage (5.49%; 95% confidence interval, 3.91-7.06 cm²). The exception was total leg fat percentage, which significantly decreased (-3.19%; 95% confidence interval, -5.98 to -0.41%). No interactive effects were observed between menopausal status and age across all fat mass measures.

CONCLUSION

The change in fat mass quantity between premenopausal and postmenopausal women was attributable predominantly to increasing age; menopause had no significant additional influence. However, the decrease in total leg fat percentage and increase in measures of central fat are indicative of a possible change in fat mass distribution after menopause. These changes are likely to, at least in part, be due to hormonal shifts that occur during midlife when women have a higher androgen (ie, testosterone) to estradiol ratio after menopause, which has been linked to enhanced central adiposity deposition. Evidently, these findings suggest attention should be paid to the accumulation of central fat after menopause, whereas increases in total fat mass should be monitored consistently across the lifespan.

Ovariectomy modify local renin-angiotensin-aldosterone system gene expressions in the heart of ApoE (-/-) mice

AIMS

The evaluation of the local Renin-Angiotensin-Aldosterone system (RAAS) gene expressions in the heart of ovariectomized (OVX) apolipoprotein E deficient mice (ApoE).

METHODS

Four-months old C57BL/6 female mice (wild-type, wt, n=20), and ApoE female mice (n=20), were submitted to OVX or a surgical procedure without ovary removal (SHAM) and formed four groups (n=10/group): SHAM/wt, SHAM/ApoE, OVX/wt, and OVX/ApoE.

KEY FINDINGS

OVX led to greater body mass, plasma triglycerides (TG) and total cholesterol, and resulted in insulin resistance and altered RAAS gene expressions in the heart tissue. The gene expression of angiotensin-converting enzyme (ACE)-2 was lower in OVX/wt than in SHAM/wt (P=0.0004), Mas receptor (MASr) was lower in OVX/wt compared to SHAM/wt (P<0.0001). Also, angiotensin II receptor type 1 (AT1r) was higher in OVX/wt than in SHAM/wt (P=0.0229), and AT2r was lower in OVX/wt than in SHAM/wt (P=0.0121). OVX and ApoE deficiency showed interaction potentializing the insulin resistance, increasing TG levels and altering ACE and MASr gene expressions. ACE gene expression was higher in OVX/ApoE than in OVX/wt (P<0.0001), and MASr gene expression was lower in OVX/ApoE than in OVX/wt (P<0.0001).

SIGNIFICANCE

The impact of OVX on local RAAS cascade in the heart of ApoE deficient animals, besides the metabolic changes culminating with insulin resistance, involves an upregulation of renin, ACE, and AT1r gene expressions. The findings may contribute to clarify the mechanisms of development of postmenopausal hypertension and the link between RAAS and apolipoprotein E.

20-Hydroxyecdysone attenuates cardiac remodeling in spontaneously hypertensive rats

BACKGROUND

Ecdysteroids, a group of steroid hormones found in insects and many plants, have been shown to prevent various changes in mammalian tissues after female sex hormone deprivation.

PURPOSE

To examine whether an ecdysteroid, 20-hydroxyecdysone (20-HE), exhibits regulatory or protective roles in the cardiovascular system.

STUDY DESIGN/METHOD

Blood pressure and cardiac function were evaluated in spontaneously hypertensive rats (SHR) during and after daily treatment with 20-HE for six weeks.

RESULTS

The progressive increase in systolic blood pressure with age in SHR rats was significantly lower in animals treated with either 5 or 10mg/kg body weight of 20-HE. However, treatment with 20-HE did not diminish the increase in diastolic pressure. Echocardiography after six weeks of treatment demonstrated that the left ventricular chamber of SHR rats treated with 20-HE was smaller than that of SHR controls, while contractility was not affected by 20-HE. Histological images also demonstrated a decrease in cardiomyocyte cross-sectional area in 20-HE treated groups. Interestingly, treatment with 20-HE caused a shift in cardiac myosin heavy chain towards more β-isoforms. SHR rats treated with 20-HE also exhibited a decrease in seminal vesicular weight and an increase in testicular weight, especially at a dose of 10mg/kg body weight. This finding suggests a possible anti-androgenic effect of 20-HE.

CONCLUSION

Our finding reveal that 20-HE has a beneficial effect on reducing blood pressure and consequently preventing dilated cardiac hypertrophy in SHR rats.