Estrogen and estrogen-progestogen replacement: therapy and cardiovascular diseases

The role of hormones, cytokines and heat shock proteins during age-related muscle loss

Ageing is associated with a progressive decline of muscle mass, strength, and quality, a condition known as sarcopenia. Due to the progressive ageing of western populations, age-related sarcopenia is a major public health problem. Several possible mechanisms for age-related muscle atrophy have been described; however the precise contribution of each is unknown. Age-related muscle loss is thought to be a multi-factoral process composed of events such as physical activity, nutritional intake, oxidative stress, inflammatory insults and hormonal changes. There is a need for a greater understanding of the loss of muscle mass with age as this could have a dramatic impact on the elderly and critically ill if this research leads to maintenance or improvement in functional ability. This review aims to outline the process of skeletal muscle degeneration with ageing, normal and aberrant skeletal muscle regeneration, and to address recent research on the effects of gender and sex steroid hormones during the process of age-related muscle loss.

Autonomic responses to psychological stress: The influence of menopausal status

Cardiovascular disease is the leading killer of women in developed countries. Menopause, stress, and lack of social support may contribute to the increased risk of heart disease morbidity and mortality in women. This study examined the effects of psychological stress and social support on autonomic nervous system control of the heart in 18 pre- and 34 postmenopausal women. Autonomic activity, as indexed by high-frequency heart rate variability and pre-ejection period, was assessed at rest and during a public speech task. Social support was determined using the Berkman Social Support Inventory. Postmenopausal women had higher heart rate (F = 4.4, p pound.04) and less parasympathetic activity (F = 11.9, p pound.001) compared with premenopausal women at rest. In response to stress, sympathetic nervous system activity increased in postmemopausal women (F = 6.1, p pound.02); however, this effect was no longer significant when age was used as a covariate in the analysis. Social support did not significantly affect measures of autonomic activity in either the pre- or postmenopausal women. Postmenopausal women have greater sympathetic and less parasympathetic activity than premenopausal women, which may account for their increased risk of coronary artery disease.

Treatment of osteoporosis: current status and recent advances

With the advent of new treatment choices, osteoporosis should no longer be considered an inevitable part of aging but rather a disease that can be treated. This article provides an overview of recent advances in treatment of osteoporosis.

Are estrogens of import to primate/human ovarian folliculogenesis?

The notion that estrogens play a meaningful role in ovarian folliculogenesis stems from a large body of in vitro and in vivo experiments carried out in certain rodent models, (e.g., rats) wherein the stimulatory role of estrogen on granulosa cell growth and differentiation is undisputed. However, evidence derived from these polyovulatory species may not be readily generalizable to the monoovulatory subhuman primates, let alone the human. Only recently, significant observations on the ovarian role(s) of estrogen have been reported for the primate/human. It is thus the objective of this communication to review the evidence for and against a role for estrogens in primate/human ovarian follicular development with an emphasis toward the application of the concepts so developed to contemporary reproductive physiology and to the practice of reproductive medicine. The role(s) of estrogens will be examined not only by analyzing the physiological evidence to the effect that these hormones control ovarian function and follicular growth, but also by summarizing the molecular evidence for the existence and distribution of the cognate receptors.

Oestrogen and vascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in postmenopausal women. Epidemiological studies consistently suggest that oestrogen administered to postmenopausal women confers an estimated 30-50% reduction in risk of development and progression of CVD. The long term effect on the cardiovascular system of the addition of a progestogen to the replacement regimen is currently unknown. In addition, it may be argued that it remains to be proven whether the magnitude of the oestrogen-induced cardioprotective effect demonstrated in these observational studies is a real biological phenomenon. No prospective, randomised, controlled studies examining the effect of oestrogen on primary and secondary prevention of CVD have been completed. However, a large number of biologically plausible mechanisms have been identified which provide evidence to support the proposed oestrogen-induced cardioprotection. These include oestrogen mediated favourable changes in metabolic profile, in particular changes in lipid metabolism, insulin resistance and the fibrinolytic system. In addition, recent data have shown that oestrogen may affect vascular structure and function by a variety of mechanisms. It has been shown that oestrogen may induce acute and chronic coronary and cerebral vasodilation through both direct (vascular smooth muscle) and indirect (endothelium dependent) mechanisms. Oestrogen also has recently been shown to have complex anti-atherogenic and antioxidant properties. Much less is known of the vascular effects of progestogens. Progestogens currently in clinical use have androgenic properties and may attenuate the beneficial effects of oestrogen by neutralising or opposing the lipid lowering, vasodilatory and anti-atherogenic actions of oestrogen. Thus further studies are required to elucidate the effects on arterial physiology and CVD outcome of the oestrogens and progestogens of different types, doses and routes of administration which are collectively referred to as postmenopausal 'hormone replacement therapy'.

EM-652 (SCH 57068), a third generation SERM acting as pure antiestrogen in the mammary gland and endometrium

Breast cancer is the most frequent cancer in women while it is the second cause of cancer death. Estrogens are well recognized to play the predominant role in breast cancer development and growth and much efforts have been devoted to the blockade of estrogen formation and action. The most widely used therapy of breast cancer which has shown benefits at all stages of the disease is the use of the antiestrogen Tamoxifen. This compound, however, possesses mixed agonist and antagonist activity and major efforts have been devoted to the development of compounds having pure antiestrogenic activity in the mammary gland and endometrium. Such a compound would avoid the problem of stimulation of the endometrium and the risk of endometrial carcinoma. We have thus synthesized an orally active non-steroidal antiestrogen, EM-652 (SCH 57068) and the prodrug EM-800 (SCH57050) which are the most potent of the known antiestrogens. EM-652 is the compound having the highest affinity for the estrogen receptor, including estradiol. It has higher affinity for the ER than ICI 182780, hydroxytamoxifen, raloxifene, droloxifene and hydroxytoremifene. EM-652 has the most potent inhibitory activity on both ER alpha and ER beta compared to any of the other antiestrogens tested. An important aspect of EM-652 is that it inhibits both the AF1 and AF2 functions of both ER alpha and ER beta while the inhibitory action of hydroxytamoxifen is limited to AF2, the ligand-dependent function of the estrogen receptors. AF1 activity is constitutive, ligand-independent and is responsible for mediation of the activity of growth factors and of the ras oncogene and MAP-kinase pathway. EM-652 inhibits Ras-induced transcriptional activity of ER alpha and ER beta and blocks SRC-1-stimulated activity of the two receptors. EM-652 was also found to block the recruitment of SRC-1 at AF1 of ER beta, this ligand-independent activation of AF1 being closely related to phosphorylation of the steroid receptors by protein kinase. Most importantly, the antiestrogen hydroxytamoxifen has no inhibitory effect on the SRC-1-induced ER beta activity while the pure antiestrogen EM-652 completely abolishes this effect, thus strengthening the need to use pure antiestrogens in breast cancer therapy in order to control all known aspects of ER-regulated gene expression. In fact, the absence of blockade of AF2 by hydroxytamoxifen could explain why the benefits of tamoxifen observed up to 5 years become negative at longer time intervals and why resistance develops to tamoxifen. EM-800, the prodrug of EM-652, has been shown to prevent the development of dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat, a well-recognized model of human breast cancer. It is of interest that the addition of dehydroepiandrosterone, a precursor of androgens, to EM-800, led to complete inhibition of tumor development in this model. Not only the development, but also the growth of established DMBA-induced mammary carcinoma was inhibited by treatment with EM-800. An inhibitory effect was also observed when medroxyprogesterone was added to treatment with EM-800. Uterine size was reduced to castration levels in the groups of animals treated with EM-800. An almost complete disappearance of estrogen receptors was observed in the uterus, vaginum and tumors in nude mice treated with EM-800. EM-652 was the most potent antiestrogen to inhibit the growth of human breast cancer ZR-75-1, MCF-7 and T-47D cells in vitro when compared with ICI 182780, ICI 164384, hydroxytamoxifen, and droloxifene. Moreover, EM-652 and EM-800 have no stimulatory effect on the basal levels of cell proliferation in the absence of E2 while hydroxytamoxifen and droloxifene had a stimulatory effect on the basal growth of T-47D and ZR-75-1 cells. EM-652 was also the most potent inhibitor of the percentage of cycling cancer cells. (ABSTRACT TRUNCATED)

Prevention of development of dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in the rat by the new nonsteroidal antiestrogen EM-800 (SCH57050)

The effect of EM-800, a new non-steroidal antiestrogen having pure antiestrogenic activity, was studied on chemical carcinogenesis induced by dimethylbenz(a)anthracene (DMBA) as well as on serum lipids and bone mass in the rat. Treatment with EM-800 orally, once daily, for 282 days (9 months), starting 3 days before DMBA administration, decreased the incidence of tumors from 95% in control animals to 60% (p < 0.01), 38% (p < 0.01), and 28% (p < 0.01) at the daily doses of 25 microg, 75 microg, and 250 microg, respectively. The average number of tumors per animal decreased from 4.5 +/- 0.5 tumors in the control group to 0.9 +/- 0.2 (p < 0.01), 0.5 +/-0.2 (p < 0.01), and 0.3 +/- 0.1 (p < 0.01) tumors in the rats treated with the above-indicated doses of the anti-estrogen. In addition, treatment with the increasing doses of EM-800 reduced serum cholesterol levels to 64%, 56%, and 48% of control, while serum triglycerides decreased to 31%, 28%, and 30% of control. Bone mineral content (BMC) and bone mineral density (BMD) of total skeleton, femur, and lumbar spine were not significantly affected following 282 days of treatment with EM-800. However, treatment with EM-800 inhibited the urinary ratio of hydroxyproline to creatinine (HP/Cr) from 14.0 +/- 3.90 micromol/mmol in controls to 7.6 +/-0.8 (p < 0.05), 6.8 +/- 0.8 (p < 0.01), and 6.8 +/- 1.1 (p < 0.01) micromol/mmol, respectively, while the same treatment had no effect on serum total alkaline phosphatase (tALP) activity or urinary calcium and phosphorus excretion. The 25 microg, 75 microg, and 250 microg daily doses of EM-800 inhibited uterine weight by 35% (p < 0.01), 62% (p < 0.01), and 66% (p < 0.01), while vaginal weight was reduced by 8% (p < 0.05), 30% (p < 0.01), and 38% (p < 0.01), respectively. In agreement with the 27% increment (p < 0.05) in ovarian weight at the highest anti-estrogen dose used, serum androstenedione (p < 0.05), androst-5-ene-3beta,17beta-diol (p < 0.01), testosterone (p < 0.05), and estradiol (p < 0.01) levels were increased. The present data show that EM-800 prevents the development of DMBA-induced mammary tumors while simultaneously inhibiting uterine and vaginal weight, reducing serum cholesterol and triglyceride levels, and having no adverse effect on bone mass following 9 months of treatment in the rat.

Physical activity in adolescence and bone density in peri- and postmenopausal women: a population-based study

The association between sports participation during adolescence and peri- and postmenopausal bone mineral density (BMD) was examined among 2025 women aged 48-58 years. Adolescent recreational and competitive sporting activities were registered with a self-administered questionnaire. Altogether, 881 (43.5%) women stated that they had taken part in sports during their adolescence. BMD was measured using dual X-ray absorptiometry (DXA) in lumbar vertebrae 2-4 and the left femoral neck. The unadjusted BMD was 2.4% higher (p = 0.001) and the adjusted BMD was 1.4% higher in the spine (p = 0.015 after adjusting for age, weight, time from menopause to densitometry, and duration of estrogen replacement therapy) among women who had taken part in sports during their adolescence compared to women who had been inactive. There was no significant difference in femoral neck BMD between these groups. The results of this population-based study suggest that intense recreational physical activity in adolescence could play some role in preventing axial osteoporosis in later life.

Combined effects of dehydroepiandrosterone and EM-800 on bone mass, serum lipids, and the development of dimethylbenz(A)anthracene-induced mammary carcinoma in the rat

Although treatment with dehydroepiandrosterone (DHEA) and the antiestrogen EM-800 alone decreased dimethylbenz(A)anthracene (DMBA)-induced mammary tumor incidence from 95% to 57% and 38%, respectively, approximately 9 months after DMBA administration, only two tumors developed in the group of animals that received the combination of DHEA and EM-800, and these two tumors disappeared before the end of the experiment (P < 0.01 vs. DHEA or EM-800 alone). Average tumor number per tumor-bearing animal as well as average tumor area per tumor-bearing animal were further decreased in animals that received the combination therapy compared with the effect of each treatment alone (P < 0.01). DHEA induced 6.9% (P < 0.01), 10.6% (P < 0.05), and 8.2% (P < 0.01) increases in bone mineral density of total skeleton, lumbar spine, and femur, respectively. The addition of EM-800 to DHEA did not affect the enhancing effect of DHEA on bone mass. The combination of the two drugs had important inhibitory effects on the urinary excretion of calcium and phosphorus as well as on the urinary hydroxyproline/creatinine ratio. Serum total alkaline phosphatase was stimulated by DHEA. Treatment with EM-800 decreased both serum triglyceride and cholesterol levels, whereas DHEA had an inhibitory effect on serum triglycerides. Although treatment with EM-800 caused a marked atrophy of the mammary gland, DHEA alone reduced lobular hyperplasia seen in aged intact rats while causing an androgen-specific stimulation of the same structures in animals already receiving the antiestrogen EM-800. The combination of DHEA and EM-800 lowered ovarian weight by 24% (P < 0.01) and decreased serum estradiol concentrations to intact control levels, whereas each compound alone had no effect on ovarian weight and stimulated serum estradiol levels by 45% (P < 0.05) and 46% (P < 0.05), respectively. Treatment with EM-800 caused a marked inhibition of uterine and vaginal weight. The present data show the additive inhibitory effects of DHEA and EM-800 on the development of DMBA-induced mammary carcinoma in the rat, thus suggesting the potential benefits of such a combination for the prevention of breast cancer in women while preserving or even increasing bone mass and maintaining a favorable lipid profile.

Androgen receptor-mediated antagonism of estrogen-dependent low density lipoprotein receptor transcription in cultured hepatocytes

Postmenopausal women receiving hormone replacement therapy have a lower risk of coronary heart disease than women who do not receive hormone treatment. Multiple mechanisms are likely to underlie estrogen's cardioprotective action, including lowering of plasma low density lipoprotein (LDL) cholesterol. Using an in vitro system exhibiting normal regulation of LDL receptor (LDLR) gene transcription, we show that 17beta-estradiol activates the LDLR promoter in transiently transfected HepG2 cells. LDLR activation by estrogen in HepG2 cells is dependent on the presence of exogenous estrogen receptor, and the estrogen-responsive region of the LDLR promoter colocalizes with the sterol response element previously identified. The estrogen response is concentration dependent, saturable, and sensitive to antagonism by estrogen receptor antagonists. Further, we show that compounds with androgen receptor agonist activity attenuate the estrogen-induced up-regulation of LDLR in our model system. Progestins with androgen receptor agonist activity, such as medroxyprogesterone acetate, also suppress estrogen's effects on LDLR expression through their androgenic properties. Characterization of the interplay between these hormone receptors on the LDLR in vitro system may allow a better understanding of the actions of sex steroids on LDLR gene expression and their roles in cardiovascular disease.

Effect of dehydroepiandrosterone on bone mass, serum lipids, and dimethylbenz(a)anthracene-induced mammary carcinoma in the rat

The present study investigated the effect of dehydroepiandrosterone (DHEA) on bone mass and serum lipids in the rat with dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma. The animals received DHEA once daily, percutaneously, at the dose of 5, 10, or 20 mg for 9 months following a single dose of 20 mg DMBA at 50-52 days of age. Bone mineral content (BMC) and bone mineral density (BMD) of total skeleton, lumbar spine, and femur were measured by dual energy x-ray absorptiometry. A 9-month treatment with DHEA increased BMC and BMD of total skeleton by 14.2% to 14.5% (all P < 0.01) and 6.7% to 8.3% (all P < 0.01), respectively. Similarly, femoral BMC and BMD were stimulated by 13.6% to 14.7% (all P < 0.05) and by 8.1% to 9.5% (all P < 0.01), respectively. In addition, BMD of lumbar spine was increased by 10.4% to 10.8% (all P < 0.05), whereas the 9.4% to 11.1% increment in BMC of lumbar spine was not statistically significant. Treatment with DHEA led to 26% (NS), 60% (P < 0.01), and 62% (P < 0.01) decreases in serum triglyceride levels at the same doses. On the other hand, no significant change in serum cholesterol concentrations was observed. Two hundred and seventy-nine days after DMBA administration, the incidence of mammary carcinoma had decreased from 95% in control animals to 73% (P < 0.05), 57% (P < 0.01), and 38% (P < 0.01) at the daily percutaneous doses of 5, 10, and 20 mg of DHEA, respectively. Moreover, the mean tumor number per tumor-bearing animal and the mean tumor area per tumor-bearing animal were also reduced by the same treatments. DHEA increased serum total alkaline phosphatase activity and decreased urinary calcium excretion, but had no effect on the urinary ratio of hydroxyproline to creatinine and urinary phosphorus excretion. These data show that DHEA exerts a stimulatory effect on bone mass and an inhibitory effect on serum triglycerides, as well as a preventive effect on the development of mammary carcinoma induced by DMBA in the rat. Such data suggest that while decreasing the risk of breast cancer, DHEA replacement therapy could also exert beneficial effects on the bone and lipid metabolism in women receiving DHEA replacement therapy.

Cardiovascular risk factors during sequentially combined 17 beta oestradiol and dydrogesterone (Femoston); results from a one-year study in postmenopausal women

OBJECTIVES

To assess the effects of Femoston (2 mg micronised 17 beta oestradiol daily, sequentially combined in one tablet with 10 mg dydrogesterone for 14 days per 28 day cycle) on the serum lipid profile of postmenopausal women.

METHODS

188 healthy postmenopausal women with intact uteri (aged 40 to 65 years) were enrolled in an open, multicentre, one-year study. Serum lipids and lipoproteins were measured at baseline and after 3, 6 and 12 months.

RESULTS

A total of 155 women completed the one-year study. Mean serum levels of total cholesterol and low-density lipoprotein (LDL)-cholesterol were significantly reduced (P < 0.01) at all assessments compared with baseline; the reductions observed at the final assessment were 5 and 20%, respectively. A significant increase of 20% (P < 0.01) was seen in high-density lipoprotein (HDL)-cholesterol levels by month 12. Mean levels of triglycerides were also increased (p < 0.01). Blood pressure and heart rate remained unchanged throughout the study.

CONCLUSIONS

The results show that the overall effects of Femoston on the serum lipid profile are comparable to those found with oestrogen therapy alone and should reduce the risk of cardiovascular disease in postmenopausal women.

Gender does not influence acute myocardial infarction in adult dogs

Mechanisms responsible for the well-documented "protection" against myocardial ischemia and infarction in young women and subsequent loss of protection after menopause remain speculative. One possibility is that gender-related variables (such as endogenous hormone levels or regular loss of stored iron) alter the susceptibility of the heart to ischemia: if so, then premenopausal women when compared with men may manifest endogenous protection against acute myocardial ischemic injury. Using the canine model we therefore sought to determine whether gender influences acute myocardial ischemia and infarction. Retrospective analysis was performed on data compiled from 60 mature adult dogs subjected to 1 hour of coronary artery occlusion and > or = 4 hours of reperfusion. We first compared the incidence of lethal ventricular fibrillation in the male and female cohorts and then for survivors compared collateral blood flow during coronary occlusion (by injection of radioactive microspheres), infarct size (assessed by tetrazolium staining and expressed as a percentage of the myocardium at risk), and regional wall motion (by somomicrometry) in the infarct-related area. The incidence of lethal ventricular fibrillation was 23% in the male dogs and 19% in the female dogs (p = 0.70, difference not significant). For survivors, the area at risk of infarction was comparable in males and females (23 +/- 2% and 22% +/- 1% of the total left ventricular weight), and the groups were equally ischemic during coronary occlusion, with collateral blood flow to the ischemic subendocardium averaging 0.05 +/- 0.02 and 0.07 +/- 0.01 ml/min/g tissue.(ABSTRACT TRUNCATED AT 250 WORDS)