Do different delivery systems of estrogen therapy influence serum lipids differently in surgically menopausal women?

Intranasal 17β-Estradiol Modulates Spatial Learning and Memory in a Rat Model of Surgical Menopause

Exogenously administered 17β-estradiol (E2) can improve spatial learning and memory, although E2 also exerts undesired effects on peripheral organs. Clinically, E2 has been solubilized in cyclodextrin for intranasal administration, which enhances brain-specific delivery. Prior work shows that the cyclodextrin structure impacts region-specific brain distribution of intranasally administered small molecules. Here, we investigated (1) cyclodextrin type-specific modulation of intranasal E2 brain distribution, and (2) cognitive and peripheral tissue effects of intranasal E2 in middle-aged ovariectomized rats. First, brain and peripheral organ distribution of intranasally administered, tritiated E2 was measured for E2 solubilized freely or in one of four cyclodextrin formulations. The E2-cyclodextrin formulation with greatest E2 uptake in cognitive brain regions versus uterine horns was then compared to free E2 on learning, memory, and uterine measures. Free E2 improved spatial reference memory, whereas E2-cyclodextrin impaired spatial working memory compared to their respective controls. Both E2 formulations increased uterine horn weights relative to controls, with E2-cyclodextrin resulting in the greatest uterine horn weight, suggesting increased uterine stimulation. Thus, intranasal administration of freely solubilized E2 is a strategic delivery tool that can yield a cognitively beneficial impact of the hormone alongside decreased peripheral effects compared to intranasal administration of cyclodextrin solubilized E2.

Sex differences in lipid and lipoprotein metabolism

BACKGROUND

Endogenous sex hormones are important for metabolic health in men and women. Before menopause, women are protected from atherosclerotic cardiovascular disease (ASCVD) relative to men. Women have fewer cardiovascular complications of obesity compared to men with obesity. Endogenous estrogens have been proposed as a mechanism that lessens ASCVD risk, as risk of glucose and lipid abnormalities increases when endogenous estrogens decline with menopause. While baseline risk is higher in males than females, endogenously produced androgens are also protective against fatty liver, diabetes and ASCVD, as risk goes up with androgen deprivation and with the decline in androgens with age.

SCOPE OF REVIEW

In this review, we discuss evidence of how endogenous sex hormones and hormone treatment approaches impact fatty acid, triglyceride, and cholesterol metabolism to influence metabolic and cardiovascular risk. We also discuss potential reasons for why treatment strategies with estrogens and androgens in older individuals fail to fully recapitulate the effects of endogenous sex hormones.

MAJOR CONCLUSIONS

The pathways that confer ASCVD protection for women are of potential therapeutic relevance. Despite protection relative to men, ASCVD is still the major cause of mortality in women. Additionally, diabetic women have similar ASCVD risk as diabetic men, suggesting that the presence of diabetes may offset the protective cardiovascular effects of being female through unknown mechanisms.

Gaps, limitations and new insights on endogenous estrogen and follicle stimulating hormone as related to risk of cardiovascular disease in women traversing the menopause: A narrative review

While it is known that estrogen protects heart health in women prior to menopause, its role after menopause and during the menopause transition is far less apparent. Previous reviews summarizing the literature on the impact of endogenous estrogen on risk of cardiovascular disease (CVD) have focused on postmenopausal women and have not come to a clear conclusion. No previous review has summarized the associations between follicle stimulating hormone (FSH), a proxy measure of the menopause transition, and CVD risk. The main purpose of this narrative review is to highlight gaps and limitations in the literature on endogenous estrogen and FSH as related to CVD risk. Future directions are addressed in light of recent findings in the field. When studying the relationship of estrogen to cardiovascular risk, it is critical to separate endogenously produced estrogen from exogenously administered estrogen. Moreover, other reproductive hormones such as FSH should be assessed, since growing evidence suggests a potential contribution of this hormone. Evaluation of estrogen changes over time allows a separation of women based on their hormone trajectories. These individual trajectories correlate with subclinical CVD and thus indicate that it is much more important to observe a woman over time rather than ascribe risk to a single determination at a single time point. As women progress through menopause and the ovary stops producing estradiol, the nature of the relationship between estrogens and subclinical CVD markers also appears to undergo a switch. Studies are needed to examine the midlife course of endogenous estradiol, FSH and CVD risk. These studies should also consider other hormones, including androgens, with an eye towards helping women modify their cardiovascular risk in midlife, when prevention is most likely possible.

Role of Estrogens in the Regulation of Liver Lipid Metabolism

Before menopause, women are protected from atherosclerotic heart disease associated with obesity relative to men. Sex hormones have been proposed as a mechanism that differentiates this risk. In this review, we discuss the literature around how the endogenous sex hormones and hormone treatment approaches after menopause regulate fatty acid, triglyceride, and cholesterol metabolism to influence cardiovascular risk.The important regulatory functions of estrogen signaling pathways with regard to lipid metabolism have been in part obscured by clinical trials with hormone treatment of women after menopause, due to different formulations, routes of delivery, and pairings with progestins. Oral hormone treatment with several estrogen preparations increases VLDL triglyceride production. Progestins oppose this effect by stimulating VLDL clearance in both humans and animals. Transdermal estradiol preparations do not increase VLDL production or serum triglycerides.Many aspects of sex differences in atherosclerotic heart disease risk are influenced by the distributed actions of estrogens in the muscle, adipose, and liver. In humans, 17β-estradiol (E2) is the predominant circulating estrogen and signals through estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), and G-protein-coupled estrogen receptor (GPER). Over 1000 human liver genes display a sex bias in their expression, and the top biological pathways are in lipid metabolism and genes related to cardiovascular disease. Many of these genes display variation depending on estrus cycling in the mouse. Future directions will likely rely on targeting estrogens to specific tissues or specific aspects of the signaling pathways in order to recapitulate the protective physiology of premenopause therapeutically after menopause.

Daily apple versus dried plum: impact on cardiovascular disease risk factors in postmenopausal women

BACKGROUND

Evidence suggests that consumption of apple or its bioactive components modulate lipid metabolism and reduce the production of proinflammatory molecules. However, there is a paucity of such research in human beings.

OBJECTIVE

Women experience a lower rate of cardiovascular disease before menopause compared with men. However, after the onset of menopause, the risk of cardiovascular disease increases drastically due to ovarian hormone deficiency. Hence, we conducted a 1-year clinical trial to evaluate the effect of dried apple vs dried plum consumption in reducing cardiovascular disease risk factors in postmenopausal women.

DESIGN

One-hundred sixty qualified postmenopausal women were recruited from the greater Tallahassee, FL, area during 2007-2009 and were randomly assigned to one of two groups: dried apple (75 g/day) or dried plum (comparative control). Fasting blood samples were collected at baseline, 3, 6, and 12 months to measure various parameters. Physical activity recall and 7-day dietary recall were also obtained.

RESULTS

Neither of the dried fruit regimens significantly affected the participants' reported total energy intake throughout the study period. On the contrary, women who consumed dried apple lost 1.5 kg body weight by the end of the study, albeit not significantly different from the dried plum group. In terms of cholesterol, serum total cholesterol levels were significantly lower in the dried apple group compared with the dried plum group only at 6 months. Although dried plum consumption did not significantly reduce serum total cholesterol and low-density lipoprotein cholesterol levels, it lowered their levels numerically by 3.5% and 8%, respectively, at 12 months compared with baseline. This may explain the lack of significance observed between the groups. However, within the group, women who consumed dried apple had significantly lower serum levels of total cholesterol and low-density lipoprotein cholesterol by 9% and 16%, respectively, at 3 months compared with baseline. These serum values were further decreased to 13% and 24%, respectively, after 6 months but stayed constant thereafter. The within-group analysis also reported that daily apple consumption profoundly improved atherogenic risk ratios, whereas there were no significant changes in lipid profile or atherogenic risk ratios as a result of dried plum consumption. Both dried fruits were able to lower serum levels of lipid hydroperoxide and C-reactive protein. However, serum C-reactive protein levels were significantly lower in the dried plum group compared with the dried apple group at 3 months.

CONCLUSIONS

There were no significant differences between the dried apple and dried plum groups in altering serum levels of atherogenic cholesterols except total cholesterol at 6 months. However, when within treatment group comparisons are made, consumption of 75 g dried apple (about two medium-sized apples) can significantly lower atherogenic cholesterol levels as early as 3 months. Furthermore, consumption of dried apple and dried plum are beneficial to human health in terms of anti-inflammatory and antioxidative properties.

Cardiovascular risk assessment with oxidised LDL measurement in postmenopausal women receiving intranasal estrogen replacement therapy

OBJECTIVE

To investigate the effect of intranasal estrogen replacement therapy administered to postmenopausal women alone or in combination with progesterone on markers of cardiovascular risk.

METHODS

The study was conducted with 44 voluntary postmenopausal women. In group I (n = 15), the patients were treated with only intranasal estradiol (300 μg/day estradiol hemihydrate). In group II (n = 11), the patients received cyclic progesterone (200 mg/day micronized progesterone) for 12 days in each cycle in addition to continuous intranasal estradiol. Group III (n = 18) was the controls. Serum lipid profiles, oxidised low-density lipoprotein (LDL) and other markers of cardiovascular risk were assessed at baseline and at the 3rd month of the treatment.

RESULTS

Lipid profile, LDL apolipoprotein B, lipoprotein a, homocysteine, oxidised LDL values and oxidised LDL/LDL cholesterol ratio were not observed to change after 3 months compared to baseline values within each group (p > 0.016). In comparison to changes between the groups after the treatment, only oxidised LDL levels and oxidised LDL/LDL cholesterol ratios of group II were increased compared to control group (p < 0.05).

CONCLUSIONS

Intranasal estradiol alone did not appear to have an effect on markers of cardiovascular risk in healthy postmenopausal women. However, the addition of cyclic oral micronized progesterone to intranasal estradiol influenced the markers of cardiovascular risk negatively in comparison to non-users in healthy postmenopausal women.