Effect of acute administration of estradiol 17 beta on aortic blood flow in menopausal women

Gender differences in tibial microvascular flow responses to head down tilt and lower body negative pressure

The purpose of the investigation was to study lower body negative pressure recovery in response to head down tilt position in men and women. The study examined the primary hypothesis that tibial bone microvascular flow responses to HDT and lower body negative pressure (LBNP) differ in women and men. Nine women and nine men between 20 to 30 years of age participated in the study. Tibial microvascular flow, head and tibial oxygenation and calf circumference were measured using photoplethysmography (PPG), near‐infrared spectroscopy (NIRS) and strain gauge plethysmography (SGP), respectively, during sitting (control baseline), supine, 15° HDT, and 15° HDT with 25 mmHg LBNP. Tibial microvascular flow with HDT increased by 57% from supine position (from 1.4V ± 0.7 to 2.2V ± 1.0 HDT; ANOVA P < 0.05) in men but there is no significant difference between supine and HDT in women. Ten minutes of LBNP during 15^oHDT restored tibial bone microvascular flows to supine levels, (from 2.2V±1.0 HDT to 1.1V ± 0.7 supine; ANOVA P < 0.05) in men but not in women. These data support the concept that there are gender specific microvascular responses to a fluid‐shift countermeasure such as LBNP. Thus, gender differences should be considered while developing future countermeasure strategies to headward fluid shifts in microgravity.

Gender differences in microcirculation: observation using the hamster cheek pouch

OBJECTIVES

Estrogen has been shown to play an important protective role in non-reproductive systems, such as the cardiovascular system. Our aim was to observe gender differences in vivo with regard to the increase in macromolecular permeability and leukocyte-endothelium interaction induced by ischemia/reperfusion as well as in microvascular reactivity to vasoactive substances using the hamster cheek pouch preparation.

METHODS

Thirty-six male and 36 female hamsters, 21 weeks old, were selected for this study, and their cheek pouches were prepared for intravital microscopy. An increase in the macromolecular permeability of post-capillary venules was quantified as a leakage of intravenously injected fluorescein-labeled dextran, and the leukocyte-endothelium interaction was measured as the number of fluorescent rolling leukocytes or leukocytes adherent to the venular wall, labeled with rhodamin G, during reperfusion after 30 min of local ischemia. For microvascular reactivity, the mean internal diameter of arterioles was evaluated after the topical application of different concentrations of two vasoconstrictors, phenylephrine (α1-agonist) and endothelin-1, and two vasodilators, acetylcholine (endothelial-dependent) and sodium nitroprusside (endothelial-independent).

RESULTS

The increase in macromolecular permeability induced by ischemia/reperfusion was significantly lower in females compared with males [19 (17-22) leaks/cm2 vs. 124 (123-128) leaks/cm2, respectively, p<0.001), but the number of rolling or adherent leukocytes was not different between the groups. Phenylephrine-induced arteriolar constriction was significantly lower in females compared with males [77 (73-102)% vs. 64 (55-69)%, p<0.04], but there were no detectable differences in endothelin-1-dependent vasoreactivity. Additionally, arteriolar vasodilatation elicited by acetylcholine or sodium nitroprusside did not differ between the groups.

CONCLUSION

The female gender could have a direct protective role in microvascular reactivity and the increase in macromolecular permeability induced by ischemia/reperfusion.

Identification and characterization of new mechanisms in vascular oestrogen signalling

Oestrogen exerts vasculoprotective effects in different experimental settings through inhibition of vascular smooth muscle cell proliferation, stimulation of nitric oxide production and attenuation of inflammation. Although these oestrogen-evoked beneficial effects have been attributed to oestrogen receptor alpha (ERα), also ER beta (ERβ) and the novel ER G protein-coupled receptor 30 (GPR30)/G protein-coupled ER1 probably play significant roles in vascular oestrogen signalling. Oestrogen-evoked vasculoprotective effects are well documented in various experimental models, but the underlying mechanisms are still incompletely understood. The age hypothesis represents an interesting and promising model to explain the discrepancy between experimental data showing beneficial vascular effects of oestrogen treatment and the clinical findings on hormone replacement therapy obtained in big epidemiology surveys, where no protective effect from supplementation with oestrogen is observed. Identification of novel ERs expressed also in the vascular system offers exciting opportunities for the future to find and characterize the mechanisms behind oestrogen-evoked beneficial effects in vascular health and disease. Importantly, some vascular effects of pharmacological concentrations of oestrogen are ER-independent, suggesting that oestrogen besides its specific effects through ERα, ERβ and GPR30 also affects vascular function via ER-independent mechanisms probably reflecting interaction of the hydrophobic oestrogen molecule with cell membrane properties. In this MiniReview, we focus on the importance of these different vascular ER subtypes in health and disease.

Evidence that the G protein-coupled membrane receptor GPR30 contributes to the cardiovascular actions of estrogen

Although female protection from cardiovascular diseases declines with the fall in circulating sex hormones experienced during menopause, clinical trials in older women fail to demonstrate beneficial effects for hormone replacement therapy. The recent discovery of GPR30, a membrane-bound estrogen receptor that is structurally and functionally unique from the steroid receptors ERα and ERβ, has unveiled additional signaling pathways by which estrogen may influence cardiovascular health. This review takes an organ-based approach to assess the expression and function of GPR30 in the cardiovascular system. We concluded that although the current literature does suggest a cardiovascular role for GPR30, additional exploration is necessary to fully elucidate the estrogenic actions mediated by this novel receptor.

Vasodilation in response to the GPR30 agonist G-1 is not different from estradiol in the mRen2.Lewis female rat

Our studies in the mRen2.Lewis female rat, an angiotensin II- and estrogen-dependent model of hypertension, revealed that chronic activation of estrogen receptor GPR30 markedly reduces blood pressure in ovariectomized females. The present studies measured acute vasodilation to the selective GPR30 agonist G-1 and 17-β-estradiol (10(-9)-10(-5.5) M) in isolated aortic rings and mesenteric arteries from intact mRen2.Lewis females. Maximal relaxation was greater in mesenteric vessels versus the aorta for both G-1 (47% ± 8% vs 80% ± 5% of phenylephrine preconstriction, P < 0.001) and estradiol (42% ± 7% vs 83% ± 4% of phenylephrine preconstriction, P < 0.001). The GPR30 antagonist G15 attenuated the response to both estradiol and G-1. Removal of the endothelium or pretreatment with Nitro-L-arginine methyl ester (L-NAME) partially attenuated vasorelaxation. Responses were not altered in mesenteric vessels from ovariectomized females. Immunohistochemical analysis revealed GPR30 expression in mesenteric endothelial and smooth muscle cells, and smooth muscle expression was confirmed in cultured cells. We conclude that estradiol-induced relaxation in conduit and resistance vessels from mRen2.Lewis females may be mediated by the novel estrogen receptor GPR30. The direct vasodilatory response of G-1 in resistance vessels presents one mechanism for the reduction in blood pressure induced by chronic G-1 administration.

Gender differences in artery wall biomechanical properties throughout life

Elevated large artery stiffness and pulse pressure have emerged as important risk factors for cardiovascular disease. The genders differ in large artery biomechanical properties throughout the lifespan with females displaying higher stiffness than males during the prepubertal years and a dramatic increase after menopause. Males on the other hand experience an increase in arterial stiffness postpuberty and a linear increase thereafter, suggesting that females have intrinsically stiffer large arteries than males, but that such effects are mitigated by sex steroids during the reproductive years. This review discusses anthropometric and sex steroid influences on gender differences in large artery stiffness and pressure dynamics from childhood to senescence. In particular, the sex-specific effects of estrogen, progesterone and testosterone on vascular structure and function and how these influence arterial stiffness are explored. These factors may contribute in part to the observed gender differences in the pathophysiology and clinical manifestations of cardiovascular disease.

Ischaemic heart disease in women: are there sex differences in pathophysiology and risk factors? Position paper from the working group on coronary pathophysiology and microcirculation of the European Society of Cardiology

Cardiovascular disease (CVD) is the leading cause of death in women, and knowledge of the clinical consequences of atherosclerosis and CVD in women has grown tremendously over the past 20 years. Research efforts have increased and many reports on various aspects of ischaemic heart disease (IHD) in women have been published highlighting sex differences in pathophysiology, presentation, and treatment of IHD. Data, however, remain limited. A description of the state of the science, with recognition of the shortcomings of current data, is necessary to guide future research and move the field forward. In this report, we identify gaps in existing literature and make recommendations for future research. Women largely share similar cardiovascular risk factors for IHD with men; however, women with suspected or confirmed IHD have less coronary atherosclerosis than men, even though they are older and have more cardiovascular risk factors than men. Coronary endothelial dysfunction and microvascular disease have been proposed as important determinants in the aetiology and prognosis of IHD in women, but research is limited on whether sex differences in these mechanisms truly exist. Differences in the epidemiology of IHD between women and men remain largely unexplained, as we are still unable to explain why women are protected towards IHD until older age compared with men. Eventually, a better understanding of these processes and mechanisms may improve the prevention and the clinical management of IHD in women.

The effects of hormone replacement therapy on myocardial performance in early postmenopausal women

OBJECTIVES

The results of the studies in which the effect of hormone replacement therapy (HRT) on cardiac function have been evaluated are rather disputable. In these studies, cardiac function was evaluated with conventional echocardiographic methods. This study was planned in order to investigate the effects of HRT on myocardial velocities and myocardial performance index (MPI) in healthy early postmenopausal women.

METHOD

In a prospective, controlled study, 60 healthy postmenopausal women were assigned to two groups (32 in the HRT group and 28 in the control group). After conventional echocardiographic parameters were measured, tissue Doppler echocardiography recordings were obtained from the mitral and tricuspid annulus. Systolic myocardial velocity (Sm), early and late diastolic myocardial velocities (Em and Am) and time intervals were measured and MPI was calculated. Then the symptom-limited exercise stress test using the Bruce protocol was performed. After 3 and 6 months of HRT (oral 0.625 mg conjugated estrogen + 2.5 mg medroxyprogesterone acetate/day), the same examinations were repeated. The effects of HRT on myocardial velocities, MPI and exercise time were evaluated at the 3rd and 6th months.

RESULTS

The parameters of the control group remained statistically unchanged during the study. HRT did not have any effect on segmental and mean left ventricular (LV) Sm or right ventricular (RV) Sm. However, LV Em/Am and RV Em/Am ratios significantly increased at the 6th month of HRT, and LV and RV MPI values were observed to decrease significantly as compared to basal values. Additionally, a significant increase was observed in exercise duration and metabolic equivalent values after 3 months of HRT, and this increase continued at the 6th month as well. The favorable changes in all parameters in the HRT group were significantly different from those of the control group.

CONCLUSION

Data obtained in this study suggest that HRT is not only effective for treating menopausal complaints but also increases cardiovascular performance by improving especially diastolic functions in early postmenopausal women.

Gender differences in the cardiovascular effect of sex hormones

The higher incidence of cardiovascular disease in men than in women of similar age, and the menopause-associated increase in cardiovascular disease in women, has led to speculation that gender-related differences in sex hormones have a key role in the development and evolution of cardiovascular disease. Compelling data have indicated that sex differences in vascular biology are determined not only by gender-related differences in sex steroid levels, but also by gender-specific tissue and cellular differences that mediate sex-specific responses. In this Review, we describe the sex-specific effects of estrogen and testosterone on cardiovascular risk, direct vascular effects of these sex hormones, and how these effects influence development of atherosclerosis. Cardiovascular effects of exogenous hormone administration are also discussed. Importantly, evidence has indicated that estrogens alone or in combination with progestins in postmenopausal women increase cardiovascular risk if started late after menopause, but that it possibly has beneficial cardiovascular effects in younger postmenopausal women, although data on long-term testosterone therapy are lacking. Hormone therapy should not be considered solely for primary prevention or treatment of cardiovascular disease at this time.

Changes in vascular flow after transdermal oestradiol therapy for prostate cancer: a mechanism for cardiovascular toxicity and benefit?

OBJECTIVE

To report the influence of transdermal oestradiol therapy on the vascular dynamics of men with advanced prostate cancer.

PATIENTS AND METHODS

Twenty patients with newly diagnosed locally advanced or metastatic prostate cancer (10 each) were treated using transdermal oestradiol patches. The vascular flow was assessed 6-monthly before and during a year of therapy using arterial and venous Doppler and duplex ultrasonography, arterial and venous photoplethysmography and opto-electronic plethysmography.

RESULTS

Arterial flow, as measured by the mean and peak systolic velocities and photoplethysmography, significantly increased over time. Arterial compliance initially decreased but had normalized after 12 months. The venous variables were unaffected. As a result, the total limb blood flow and the capillary filtration rate were significantly increased.

CONCLUSION

Transdermal oestradiol therapy causes an increase in arterial but not venous flow, and an initial decrease in arterial compliance, which adapts to the physiological range with time. It is possible that these changes may account for the increase in cardiovascular toxicity seen in the early phase of oestrogen therapy, and the cardioprotective effect that accrues thereafter.

Acute administration of 17β-estradiol improves endothelium-dependent vasodilation in postmenopausal women

OBJECTIVES

Estrogen's effect on endothelial function in postmenopausal women with mild hypertension but no other cardiovascular risk factors remains unclear. This study investigated the effect of an acutely administered therapeutic/low dose of 17beta-estradiol on vasodilation in this patient population.

METHODS

Forearm blood flow (FBF) was measured in seven white, hypertensive (blood pressure 144 +/- 8/93 +/- 5 mmHg), postmenopausal (mean age: 54.4 +/- 5 years) women at baseline and during the intra-brachial infusion of increasing doses of acetylcholine (ACh; 0.75, 5, and 15 microg/100 mL tissue/min) and sodium nitroprusside (NP; 1, 2, and 4 microg/100 mL tissue/min). These measurements were obtained both before and after the sublingual administration of 17beta-estradiol. Eight normotensive women (blood pressure 115 +/- 8/76 +/- 5 mmHg) with otherwise similar characteristics served as controls (mean age: 55.8 +/- 5 years). Exclusion criteria included medications or any condition that could alter endothelial function.

RESULTS

Before estradiol administration, FBF values at baseline and after all doses of ACh and NP were similar between groups. Acutely administered 17beta-estradiol significantly improved the FBF response to ACh in both the normotensive (maximal response: 17.6 +/- 5 versus 22.5 +/- 7 mL/min/100 mL) and hypertensive (11 +/- 4 versus 16 +/- 6; 12 +/- 4 versus 17 +/- 5 and 14 +/- 3 versus 20 +/- 7 mL/min/100 mL) groups. It also altered the NP dose-response curve in the both groups.

CONCLUSION

17beta-estradiol improved vasodilatory responses in mildly hypertensive postmenopausal women without other risk factors for cardiovascular disease.

Influence of 17-beta-estradiol on cerebrovascular impedance during menstrual cycle in women

Numerous experimental studies showed that estrogen alters diameters of cerebral arteries by modifying production of vasoactive substances. In this study, we address a question whether increased concentration of 17-beta-estradiol (E2) during a typical menstrual cycle of young, healthy women influences cerebrovascular impedance, as measured with Doppler pulsatility index (PI) in the common (CCA), internal (ICA), and external (ECA) carotid arteries using duplex Doppler sonography. PI was determined and correlated with plasma E2 concentration in 14 women (ages 23-25) throughout their menstrual cycle. The concentration of E2 increased in the follicular phase of the cycle and reached a peak of 140-300 pg/ml on days 13 and 14, whereas concentration of progesterone remained low (<1 ng/ml). Along with an increase in E2 concentration, the ICA PI decreased from its initial level on average by 11% on day 13 and by 7% on day 14 (r=-0.41, P<0.05). In contrast, the value of the ECA PI showed an increasing trend during the peak of E2 concentration. There were no significant changes in the CCA PI as well as in the systolic blood pressure, heart rate, hematocrit, and hemoglobin concentration during the menstrual cycle. Cerebral vascular impedance in young women is modulated by concentration of E2 throughout the menstrual cycle. The decrease in the ICA PI during the late follicular phase seems to be attributed to a decrease in cerebrovascular resistance.

Effect of postmenopausal hormone replacement therapy on cardiovascular performance

Postmenopausal hormone replacement therapy (HRT) has usually been evaluated the relationship with atherosclerotic disease, whereas its effect on direct cardiac functions hasn't been investigated in detail. This study was planned to investigate the long-term effects of HRT on cardiac functions and exercise performance.

METHODS

Thirty-six postmenopausal women (mean age: 51 +/- 4 years, 39-60 years) were prospectively analyzed with pulsed wave Doppler echocardiography and symptom-limited exercise stress test before HRT (oral 0.625 mg conjugated estrogen and 2.5 mg medroxyprogesteron acetate/day), and at the third and the sixth months. The effect of HRT on left ventricular ejection fraction (EF), early filling velocity (E wave) and late filling velocity (A wave), E wave deceleration time (EDT), E/A ratio, myocardial performance index (MPI), exercise duration and METS changes were examined.

RESULTS

HRT did not significantly alter the left ventricular EF. At the third month of HRT, there was an insignificant increase in E wave, EDT, and E/A ratio, whereas an insignificant decrease was noted in MPI (P > 0.05). However, at the sixth month of HRT, these changes became significant (68 +/- 12 vs. 75 +/- 13 cm/s, P < 0.01; 171 +/- 24 vs. 184 +/- 14 ms, P < 0.01; 1.01 +/- 0.23 vs. 1.11 +/- 0.27, P < 0.01, and 44 +/- 9 vs. 39 +/- 8%, P < 0.001, respectively). On the other hand, exercise duration and exercise METS values showed significant improvements at the third month of HRT (423 +/- 104 vs. 482 +/- 104 s, P < 0.001; 8.2 +/- 1.7 vs. 9.1 +/- 2 METS, P < 0.001). These improvements also continued at the sixth month of HRT. In conclusion, postmenopausal HRT leads to a progressive improvement on left ventricular function parameters, and in parallel, in exercise performance.

Oscillations of cerebrovascular resistance throughout the menstrual cycle in healthy women

OBJECTIVES

Increased concentration of endogenous estrogen during a typical menstrual cycle has been shown to correlate with augmentation of blood flow through the internal carotid arteries (ICAs), which may be related to changes in vascular resistance within the brain. In this study we investigated the effects of endogenous estrogen and progesterone on cerebrovascular impedance in young healthy women.

METHODS

The blood flow in the ICA and the common (CCA) and external (ECA) carotid arteries was studied with duplex Doppler sonography. The resistance index (RI) was determined and correlated with plasma 17beta-estradiol concentration in 14 young healthy women throughout their menstrual cycle.

RESULTS

The concentration of 17beta-estradiol increased in the follicular phase of the cycle and reached a peak on day 14, whereas concentration of progesterone remained low. Along with an increase in estrogen concentration, the ICA RI had decreased from its initial level on average by 9.2% on day 13 and by 6.7% on day 14 (P < 0.05). In contrast, the trend of the ECA RI was to increase during the peak of estrogen concentration. There were no significant changes in the CCA RI or in the systolic blood pressure, heart rate, hematocrit and hemoglobin concentration through the menstrual cycle.

CONCLUSIONS

Estrogen-related augmentation of blood flow through the ICA is caused mainly by decreased cerebrovascular impedance, as shown by a decrease in the ICA RI. These changes in RI suggest that estrogen influences cerebral impedance mainly by altering the resistance of cerebral microvasculature.

Evaluation of cardiovascular parameters of a selenium-based antihypertensive using pulsed Doppler ultrasound

The pharmacology of selenium is of much interest because selenium deficiency has been linked to cardiovascular diseases, cancer, and arthritis, and selenoenzymes are critical cellular antioxidants. We have previously reported that phenyl-2-aminoethylselenide (PAESe) and its derivatives represent a novel class of selenium-based antihypertensive agents that exhibit unique biochemical and pharmacologic properties. We now report on experiments designed to probe the hemodynamic mechanism of action of these compounds in spontaneously hypertensive rats (SHR). A noninvasive pulsed Doppler ultrasound probe was used to measure peak blood flow velocity in the aortic arch from the right second intercostal space. PAESe was found to increase peak aortic blood flow velocity (+44%), heart rate (+16%), and blood flow acceleration (+105%), while decreasing left ventricular ejection time (LVET) (-37%) concomitant with a decrease in mean arterial pressure (-54%). These results were compared with the known vasodilator hydralazine, which had similar effects on mean arterial pressure (MAP) and peak velocity but caused an increase in LVET (+42%) and a decrease in heart rate (-18%). Taken together, our results suggest that PAESe decreases blood pressure via a decrease in peripheral resistance, which overcomes the initial increase in heart rate and acceleration to give a net decrease in MAP.

Acute, nongenomic vasodilatory action of estradiol is attenuated by chronic estradiol treatment

Deficiency of estradiol or chronic estrogen treatment may alter the responses to this hormone in many tissues. A possible interaction between the acute nongenomic and the chronic effects of estradiol on microvessels have not been investigated yet. In the present study we have investigated whether acute in vitro vasodilatory action of estradiol on a small artery is altered by chronic estradiol pretreatment. Female rats were surgically ovariectomized and subjected to either estradiol replacement therapy (estradiol propionate, 450 micrograms/kg/week) or vehicle administration for 5 weeks. Cylindrical segments of the saphenous artery were studied using videocomputerized microarteriography in vitro. Estradiol, in concentrations of 10(-6) to 10(-4) M relaxed norepinephrine precontracted vessel segments in a dose-dependent manner. Magnitude of relaxation observed in arteries of estradiol replaced animals was significantly smaller at all concentrations than that of nonreplaced ovariectomized rats; maximal relaxation in the control ovariectomized group was 64.5% +/- 3.6%, while it was 34.3% +/- 4.2% only in the ovariectomized and estradiol replaced group (P < 0.001). Comparison of acute relaxations in response to papaverine and nifedipine failed to prove a reduced activity of the general relaxation machinery in estradiol replaced animals. We conclude that chronic estradiol replacement can downregulate the acute nongenomic vasorelaxation effect of this hormone in small arteries of ovariectomized rats.

Effects of 15 months of 17 beta-estradiol and dydrogesterone on systolic cardiac function according to quantitative and Doppler echocardiography in healthy postmenopausal women

OBJECTIVE

Our goal was to investigate the short-term and intermediate effects of low-dose hormone replacement therapy on echocardiographic parameters of cardiac function in healthy postmenopausal women.

STUDY DESIGN

In a prospective, controlled study 30 healthy postmenopausal women (mean age, 52 +/- 3 years) were randomly assigned to 2 groups. Women in the hormone replacement therapy group (n = 15) received 1 mg micronized 17 beta-estradiol daily sequentially combined with 5 or 10 mg dydrogesterone for 14 days of each 28-day cycle during 12 months and thereafter 2 mg 17 beta-estradiol combined with 10 mg dydrogesterone for a period of 3 months. The control group (n = 15) received no treatment. M-mode, quantitative 2-dimensional, and Doppler echocardiographic measurements were performed at baseline and within the 17 beta-estradiol phase at 3, 12, and 15 months.

RESULTS

After 12 months significant differences in change between the 2 groups were found for left ventricular end-diastolic and left ventricular end-systolic diameters, left ventricular mass index, and stroke volume index. These differences were caused by changes in the control group rather than in the hormone replacement therapy group, in which no significant within-group changes were found. All other parameters measured showed no effect.

CONCLUSION

Within 15 months of 17 beta-estradiol and dydrogesterone treatment no clinically relevant differences were found in the M-mode, quantitative 2-dimensional, and Doppler echocardiographic parameters measured in this study. It is suggested that 15 months of treatment probably is too short a period for detection of direct effects on the heart itself.

Effect of endogenous estrogen on blood flow through carotid arteries

BACKGROUND AND PURPOSE

Recent evidence suggests that physiological changes in the concentration of endogenous estrogens may influence stroke outcome. The purpose of this study was to determine a menstrual cycle-related profile of blood flow through the carotid arteries and its correlation with estrogen concentration.

METHODS

The flow velocity and cross-sectional area of the common carotid artery, internal carotid artery (ICA), and external carotid artery (ECA) were measured with duplex Doppler sonography throughout the menstrual cycle in 14 healthy women. Concentration of plasma 17beta-estradiol, progesterone, hematocrit, hemoglobin, and blood pressure were also determined.

RESULTS

In the follicular phase, the concentration of estrogen increased to reach a peak on day 14, whereas concentration of progesterone remained low. The mean and end-diastolic velocities in the ICA increased on average by 15% of their base values, along with increasing concentrations of estrogen (r=0.59 and 0.65, respectively). The profile of flow velocity changes in this artery corresponded to the profile of estrogen concentration. In contrast to the ICA, flow velocities in the ECA decreased from their base value, reaching their minimum in the luteal phase. The mean flow velocity in the common carotid artery increased on day 14 by just 2% of its base value. The lumen of the carotid arteries was stable throughout the cycle. Hematocrit, hemoglobin, and systolic blood pressure also remained unchanged.

CONCLUSIONS

Increased concentration of endogenous estrogen correlates with substantial augmentation of flow in the internal carotid artery. This promotion of flow is caused mainly by decreased cerebrovascular resistance with consequent "stealing" of blood from the ECA.

The acute effects of sublingual estradiol on left ventricular diastolic function in normotensive and hypertensive postmenopausal women

AIM

limited information is available on estrogen influences on diastole. We aimed to investigate the acute effects of a single dose of sublingual 17beta-estradiol on left ventricular diastolic function in postmenopausal women.

METHODS

the study included 28 women aged 55.6 +/- 6 (15 normotensive and 13 hypertensive), who underwent Doppler echocardiography and estradiol plasma levels determination before and 60 min after sublingual administration of 4 mg of 17beta-estradiol.

RESULTS

there were no modifications in heart rate. Both systolic and diastolic blood pressure dropped significantly in the hypertensives and remained unchanged in normotensives. Estradiol levels were 1790 +/- 869 pg/ml in the normotensives and 2664 +/- 1490 in the hypertensives (P < 0.05). Peak early velocity, in the population as a whole, increased from 84 +/- 18 to 91 +/- 18 cm/s and the early-to-atrial velocity ratio from 1.1 +/- 0.4 to 1.4 +/- 0.6 (P < 0.0001 for both). Both acceleration and deceleration rates increased significantly (P < 0.0001). These changes were shared by all the patients. In addition, the hypertensive patients, who presented a baseline pattern characterized mainly by a grossly increased peak atrial velocity with reduction in the early-to-atrial velocity ratio, demonstrated a decrease in peak atrial velocity from 92 +/- 12 to 78 +/- 10 cm/s (P < 0.0001), associated with significant reductions in deceleration time (P < 0.0001) and pressure half time (P < 0.005). Therefore, the typical picture of impaired ventricular relaxation was favorably changed after estradiol administration.

CONCLUSIONS

the sublingual administration of estradiol induces acute modifications in left ventricular diastolic function in postmenopausal women, with improvement in the age-related left ventricular relaxation pattern, and that these beneficial changes are more pronounced in hypertensive that in normotensive women.

The acute effects of sublingual 17beta-estradiol on the cardiovascular system

The beneficial effects of estrogen in postmenopausal women have been well documented. Cardioprotection by estrogen, which is probably the result of several metabolic alterations, appears after 2 or more years of constant use. However, acute administration of estrogen (intravenous or intracoronary) was found to improve cardiac hemodynamics and function through various non-genomic mechanisms. This article reviews data on the consequences of sublingual administration of estrogen, a non-invasive and simple dosing route which is associated with rapid absorption and prompt cardiovascular reactions. It appears that sublingual estradiol at 1 or 2 mg may improve ischemia and exercise performance in women with coronary artery disease, and augment the aortic and brachial blood flow as a result of vasodilation, whereas larger doses (4 mg) may lead to a decrease in myocardial contractility and aortic blood flow, and a slight drop in blood pressure. More data are needed to evaluate the actual clinical significance of sublingual estradiol in healthy women, in situations when endothelial dysfunction is anticipated (diabetes, hypertension) and in women with diagnosed coronary artery disease.

Lack of effects of transdermal estradiol on diastolic function: a randomized placebo-controlled double-blind short-term trial

OBJECTIVE

Limited information is available on the effects of transdermal estradiol on diastole. The present study was a randomized double-blind placebo-controlled trial designed to investigate the short-term effects of transdermal estradiol on left ventricular diastolic function in postmenopausal women.

METHODS

The study included 45 women aged 50.8 +/- 3.6 years (25 randomized to the study group and 20 to placebo), who underwent Doppler echocardiography and determination of the plasma estradiol level after 4 and 8 weeks of transdermal estradiol administration in a dose of 50 micrograms per 24 h.

RESULTS

There were no modifications in heart rate. Systolic blood pressure dropped in the study patients after 8 weeks (p < 0.03); diastolic blood pressure remained unchanged. Estradiol levels were 67 +/- 36 pg/ml at 4 weeks and 70 +/- 49 pg/ml at 8 weeks in the study group. Basal values of peak early and peak atrial velocities, acceleration time and rate, deceleration time and rate, early/atrial velocity ratio and pressure half-time were not significantly different between the estradiol and placebo groups. Doppler values remained unchanged after both 4 and 8 weeks in women receiving estradiol. Women with relatively high serum 17 beta-estradiol levels (> 100 pg/ml) at 4 or 8 weeks of treatment did not present more pronounced changes in the Doppler-derived parameters compared with patients with low hormone levels.

CONCLUSION

The results showed a lack of short-term effects of transdermal estradiol on left ventricular diastolic function in postmenopausal women, irrespective of serum estradiol levels.