Nuclear uptake of sex steroid hormones in the cardiovascular system of the baboon

Signs of diastolic dysfunction are graded by serum testosterone levels in aging C57BL/6 male mice

We investigated whether maladaptive, age-associated changes in heart structure and function were linked to circulating testosterone levels. Male C57BL/6 mice had a gonadectomy (GDX) or sham surgery at 4 weeks and effects of GDX on the heart were examined with echocardiography. Serum testosterone was measured with ELISA. Left ventricular (LV) mass increased with age but was smaller in GDX mice than sham at 18 months (144.0 ± 8.7 vs 118.2 ± 11.9 mg; p = 0.009). The isovolumic relaxation time (IVRT) declined with age but was prolonged in GDX mice at 18 months (10.5 ± 0.8 vs 12.5 ± 0.5 msec, p = 0.008). Ejection fraction did not change with age or GDX, but E/A ratios were lower in GDX mice than controls at 18 months (1.6 ± 0.2 vs 1.3 ± 0.1, p = 0.021). When links between serum testosterone and cardiac parameters were examined longitudinally in 18-24-month-old mice, LV mass declined with decreasing testosterone (β = 37.70, p = 0.016), however IVRT increased as testosterone decreased (β=-2.69, p = 0.036). Since longer IVRT and lower E/A ratios are signs of diastolic dysfunction, low circulating testosterone may promote or exacerbate diastolic dysfunction in older males. These findings suggest that lower testosterone directly modifies heart structure and function to promote maladaptive remodeling and diastolic dysfunction in the aging heart.

Treadmill exercise training prevents myocardial mechanical dysfunction induced by androgenic-anabolic steroid treatment in rats

Elevated concentrations of testosterone and its synthetic analogs may induce changes in cardiovascular function. However, the effects of the combination of anabolic/androgenic steroid (AAS) treatment and exercise training on systolic and diastolic cardiac function are poorly understood. In the present study, we aimed to investigate the effects of low-dose steroid treatment (stanozolol) on cardiac contractile parameters when this steroid treatment was combined with exercise training in rats and the effects of chronic steroid treatment on the Frank-Starling (length-tension curves) relationship. Male Wistar rats were randomly assigned to one of four groups: U (untrained), US (untrained and treated with stanozolol 5 mg/kg/week), T (trained, 16 m/min/1 h) and TS (trained and treated with stanozolol 5 mg/kg/week). Continuous exercise training was conducted 5 days/week for 8 consecutive weeks. The speed of the treadmill was gradually increased to a final setting of 16 m/min/1 h. Experiments were divided into two independent series: 1) central hemodynamic analysis for mean arterial blood pressure (MAP) and cardiac output (CO) measurements and 2) isolated papillary muscle preparation in Krebs solution. Stanozolol treatment significantly increased the MAP and the heart size in untrained and trained rats (U 113±2; T 106±2; US 138±8 and TS 130±7 mmHg). Furthermore, stanozolol significantly decreased developed tension and dT/dt (maximal and minimal) in U rats. However, the developed tension was completely restored by training. The Frank/Starling relationship was impaired in rats treated with stanozolol; however, again, training completely restored diastolic function. Taken together, the present data suggest that AAS treatment is able to decrease cardiac performance (systolic and diastolic functions). The combination of stanozolol and physical training improved cardiac performance, including diastolic and systolic functions, independent of changes in central hemodynamic parameters. Therefore, changes in ventricular myocyte calcium transients may play a cardioprotective role.

QT Dispersion in Young, Ideal, and Old Aged Pregnancies

BACKGROUND

Obstetricians regard maternal age of 20 to 35 years as the optimal age for pregnancy. Adolescent pregnancy and pregnancy at the ages of 35 years and above are associated with higher risks. Pregnancy is pro-arrhythmic and rarely precipitates ventricular arrhythmias.

OBJECTIVES

QT dispersion is an index of heterogeneity of ventricular repolarization and a predictor of propensity of ventricular arrhythmias. In this study, this index was used to find any relationship between maternal age and ventricular arrhythmia risk.

METHODS

This study was performed among a group of healthy pregnant ladies between 36 and 40 weeks of gestation. An ECG was taken from each patient. QT dispersions were calculated on a computer screen with high magnitude. The results were then divided into three groups based on the age of the participants. The first, second, and third groups included the women below 20, between 20 and 35, and over 35 years, respectively. The three groups were compared using Kruskal-Wallis test.

RESULTS

The mean QTd was 61.77 ms (± 16.61) in the first group, 64.15 ms (± 18.65) in the second group, and 55.95 ms (± 23.04) in the third group. Although QTd was prolonged in all, no significant difference was observed among the three groups regarding QTd.

CONCLUSIONS

Our results showed QT prolongation in pregnancy, but showed that maternal age did not affect the heterogeneity of ventricular repolarization and propensity of ventricular arrhythmias in pregnancy.

Enhanced spectral analysis of blood flow during post-occlusive reactive hyperaemia test in different tissue depths

The objective of this study was to investigate the impairment of microcirculation in schizophrenic patients by means of spectral analysis of blood flow signals and to determine if microcirculation is unequally altered in different tissue depths. Furthermore, the impact of gender and age on the spectral parameters of the Laser Doppler Flowmetry (LDF) signal in healthy and diseased microcirculation are to be analysed. The segmented spectral analysis (SSA) algorithm was applied to LDF signals of a provoked post-ischemic stage and compared to the traditional total spectral analysis, hypothesizing that SSA reveals more detailed information on the dynamic behaviour of the blood flow. 15 healthy subjects (CON, mean age 32.4 years) and 15 patients (PAT, mean age 33.0 years) were enrolled. Spectral analysis was performed on two LDF signals at a depth of 2mm and 6-8mm. Features in five frequency subintervals were determined. Our results indicate that microcirculation is strongly impaired in patients. SSA of blood flow revealed differences between CON and PAT in all three frequency intervals referring to local vasomotion (endothelial p=0.03; sympathetic p=0.02, myogenic p=0.03) as well as the respiratory (p=0.02) and cardiac (p=0.006) bands in the deeper tissue. In contrast, in the near-surface tissue only the endothelial (p=0.006) and cardiac (p=0.006) components were altered. Furthermore, SSA determined a gender- and age dependency regarding blood flow. In conclusion, we could demonstrate that microcirculation in schizophrenic patients is significantly impaired, depending on its location in the near-surface skin or in the superficial muscle tissue. These alterations of microcirculation are more pronounced in the deeper tissue depth of about 6-8mm and are influenced by gender and age.

Impaired aortic elastic properties in patients with adult-onset hypogonadism

BACKGROUND

Recent studies have shown a strong relationship between testosterone levels and vasomotor actions. The aim of this study is to compare the elastic properties of the aorta in male patients with hypogonadism and eugonadal healthy control subjects.

METHOD

A total of 22 male with hypogonadism (mean age: 35.2 ± 9.5 years, mean disease duration: 5.3 ± 1.8 years) and 25 age-, sex- and weight-matched eugonadal healthy subjects (mean age: 34.5 ± 8.2 years) were enrolled in the study. Aortic stiffness (β) index, aortic strain (AoS) and aortic distensibility (AoD) were calculated from the aortic diameters measured by transthoracic echocardiography and blood pressure obtained by sphygmomanometer.

RESULTS

The routinely performed echocardiographic parameters were similar between patient and control groups. There were significant differences between the control and patient groups in β index (1.75 ± 0.44 vs 2.68 ± 1.72, p < 0.001), AoS (18.52 ± 6.44 vs 12.35 ± 3.88%, p < 0.001) and AoD (7.56 ± 2.86 vs 3.96 ± 1.24, 10(-6) cm(2)/dyn, p < 0.001). There were statistically significant positive correlations between the serum total testosterone level and AoD (r = 0.539, p < 0.001) and AoS (r = 0.372, p = 0.036); moreover, there was a negative correlation between the serum total testosterone level and β index (r = - 0.462, p = 0.001). In multivariate analysis, serum total testosterone level was significantly related with AoD, AoS and β index (respectively, RR = 2.88, p = 0.004; RR = 3.45, p = 0.001; RR = 2.64, p = 0.01).

CONCLUSION

The study results showed that aortic elasticity was impaired in patients with hypogonadism. We also have demonstrated a statistically significant correlation between aortic elastic properties and the serum total testosterone level.

Effects of testosterone on cardiomyocyte calcium homeostasis and contractile function in female rats

The role of testosterone (T) in the regulation of cardiovascular function in females is not well understood. Our goal was to examine the effect of T on cardiomyocyte biology by measuring sarcomere shortening/relaxation and intracellular calcium cycling in adult female Sprague-Dawley rats. The rats were divided into the following four groups: (1) sham operated; (2) ovariectomized (OVX); (3) OVX plus T; and (4) OVX + T plus an aromatase inhibitor (AI). The final group was added to rule out effects from bioconversion of T to oestradiol. Sarcomere/calcium dynamics were measured after 4 weeks at 2 and 6 Hz, then at 6 Hz following exposure to 300 nm isoprenaline. Additionally, the acute (i.e. non-genomic) effects of T were evaluated in sham-operated and OVX + T + AI rats. There were no group differences, nor was there evidence for an effect of T on frequency or isoprenaline response. Additionally, there were no findings to indicate an acute, non-genomic T effect. Moreover, the relative α- and β-myosin heavy chain isoform complement was unchanged by OVX or T replacement. Our results argue against acute or chronic effects of T on cardiomyocyte shortening dynamics, calcium cycling or myosin heavy chain expression, arguing against any direct effect of T on cardiomyocyte function in adult females.

Emerging cardiometabolic complications of androgen deprivation therapy

Prostate cancer (PCa) is the most common malignancy in men. Androgen deprivation therapy (ADT) is used in the treatment of locally advanced and metastatic PCa. Although its use has improved survival in a subset of patients, it also has negative consequences. Osteoporosis, sexual dysfunction, hot flashes and adverse changes in body composition are well-known and well-studied complications of ADT. Recent studies have also found metabolic complications in these men such as insulin resistance, diabetes and metabolic syndrome. In addition, these men might also experience higher cardiovascular mortality. Studies are needed to determine the mechanism behind these complications and to employ strategies to prevent them.

Gender-related dissociation in outcomes in chronic heart failure: reduced mortality but similar hospitalization in women

BACKGROUND

The impact of gender on major natural history endpoints in heart failure (HF) has not been examined in a propensity-matched study.

METHODS

Of the 7788 chronic systolic and diastolic HF patients in the Digitalis Investigation Group trial 1926 were women. Propensity scores for female gender were used to assemble a cohort of 1669 pairs of men and women who were well-balanced on 32 measured baseline characteristics. Matched hazard ratios (HR) and 95% confidence intervals (CI) for outcomes associated with female gender were calculated using stratified Cox regression models.

RESULTS

All-cause mortality occurred in 36% (rate, 1256/10,000 person-years) and 30% (rate, 1008/10,000 person-years) of matched men and women respectively during 5 years of follow up (HR when women were compared with men, 0.82, 95% CI, 0.72-0.94, P=0.004). Female gender was also associated with reduced cardiovascular mortality (matched HR, 0.85; 95% CI, 0.73-0.99, P=0.037) and a trend toward reduced non-cardiovascular mortality (matched HR, 0.73; 95% CI, 0.53-1.00; P=0.053). All-cause hospitalization occurred in 67% (rate, 4003/10,000 person-years) and 65% (rate, 3762/10,000 person-years) matched male and female patients respectively (HR for women, 1.03, 95% CI, 0.93-1.15, P=0.538). Female gender was not associated with cardiovascular or HF hospitalization but was associated with hospitalization due to unstable angina pectoris (matched HR, 1.38; 95%CI, 1.11-1.72; P=0.003) and stroke (matched HR, 0.65; 95%CI, 0.46-0.92; P=0.014).

CONCLUSIONS

In patients with chronic HF, female gender has a significant independent association with improved survival but has no association with all-cause, cardiovascular, or HF hospitalizations.

Influence of angiotensin-converting enzyme gene polymorphism on development of athlete's heart

BACKGROUND AND HYPOTHESIS

Genetic influence on development of athlete's heart is uncertain. This study investigated whether angiotensin-converting enzyme (ACE) gene polymorphism influenced development of athlete's heart.

METHODS

Forty-three participants in a 100-km ultramarathon were classified on the basis of ACE gene polymorphism into a deletion group (n = 26) and an insertion group (n = 17). Echocardiograms were recorded to determine left ventricular end-diastolic and end-systolic diameters, interventricular septal thickness, left ventricular posterior wall thickness, left ventricular mass, and ejection fraction.

RESULTS

Left ventricular end-diastolic diameter (65.5 +/- 4.0 mm) and left ventricular mass (369.5 +/- 73.9 g) were significantly larger in the subjects with deletion than in those with insertion (57.4 +/- 4.2 mm, 306.5 +/- 93.7 g). However, no significant differences in the other parameters were noted.

CONCLUSIONS

In long-distance runners, ACE gene polymorphism of the D/D and D/I genotypes has a stronger influence on left ventricular hypertrophy than polymorphism of the I/I genotype.

Heart lesions associated with anabolic steroid abuse: comparison of post-mortem findings in athletes and norethandrolone-induced lesions in rabbits

Among 15,000 forensic post-mortem examinations performed on the coroner's order over a 24-year period (January 1981-December 2004) in the area of Lyon, France (population: 2,000,000), 2250 cases of unexpected cardiac sudden death were identified retrospectively according to WHO criteria. Of these, 108 occurred during recreational sport and 12 occurred in athletes. In the latter category, a history of anabolic steroid abuse was found in 6 cases, whereas pre-existing ordinary cardiac lesions were observed in the 6 remaining cases. To shed light on the possible role of anabolic steroids in the induction of cardiac lesions, an experimental study was conducted in rabbits that were treated orally with norethandrolone 8mg/kg/day for 60 days, and sacrificed at day 90. The histopathological examination of the heart from treated animals showed coronary thrombosis associated with left ventricle hypertrophy in 3 cases, and lesions analogous to toxic or adrenergic myocarditis in all other treated animals. These findings were very similar to those observed after cardiac sudden death in the 6 athletes with a history of anabolic steroid abuse. In addition, elevated caspase-3 activity in the heart of treated rabbits as compared to controls suggests that apoptosis is involved in the induction of norethandrolone-induced cardiac lesions. These results confirm the cardiotoxic potential of anabolic steroid abuse.

Contribution of epoxyeicosatrienoic acids to flow-induced dilation in arteries of male ERalpha knockout mice: role of aromatase

We studied the roles of estrogen receptors (ER) and aromatase in the mediation of flow-induced dilation (FID) in isolated arteries of male ERalpha-knockout (ERalpha-KO) and wild-type (WT) mice. FID was comparable between gracilis arteries of WT and ERalpha-KO mice. In WT arteries, inhibition of NO and prostaglandins eliminated FID. In ERalpha-KO arteries, N(omega)-nitro-L-arginine methyl ester (L-NAME) inhibited FID by approximately 26%, whereas indomethacin inhibited dilations by approximately 50%. The remaining portion of the dilation was abolished by additional administration of 6-(2-proparglyoxyphenyl)hexanoic acid (PPOH) or iberiotoxin, inhibitors of epoxyeicosatrienoic acid (EET) synthesis and large-conductance potassium channels, respectively. By using an electrophysiological technique, we found that, in the presence of 10 dyne/cm(2) shear stress, perfusate passing through donor vessels isolated from gracilis muscle of ERalpha-KO mice subjected to L-NAME and indomethacin elicited smooth muscle hyperpolarization and a dilator response of endothelium-denuded detector vessels. These responses were prevented by the presence of iberiotoxin in detector or PPOH in donor vessels. Gas chromatography-mass spectrometry (GC-MS) analysis indicated a significant increase in arterial production of EETs in ERalpha-KO compared with WT mice. Western blot analysis showed a significantly reduced endothelial nitric oxide synthase expression but enhanced expressions of aromatase and ERbeta in ERalpha-KO arteries. Treatment of ERalpha-KO arteries with specific aromatase short-interfering RNA for 72 h, knocked down the aromatase mRNA and protein associated with elimination of EET-mediation of FID. Thus, FID in male ERalpha-KO arteries is maintained via an endothelium-derived hyperpolarizing factor/EET-mediated mechanism compensating for reduced NO mediation due, at least in part, to estrogen aromatized from testosterone.

P-wave dispersion is increased in pregnancy due to shortening of minimum duration of P: does this have clinical significance?

Most pregnant women complain of palpitation, and various kinds of arrhythmias can be observed during pregnancy. We investigated P-wave and QT dispersion during pregnancy. Healthy pregnant women (n=162) and healthy age-matched, non-pregnant women (n=150) were included. We performed electrocardiography and transthoracic echocardiography and determined serum oestradiol levels in both groups, and performed Holter monitoring in the pregnant group only. Resting heart rate, P-wave dispersion, left ventricular diastolic diameter, left atrial diameter and serum oestradiol levels in the pregnant group were significantly higher than in the control group. Minimum P-wave duration was shorter in the control group than in the pregnant group; however, there was no statistically significant difference in maximum P wavelength and corrected QT dispersion between the groups. No atrial fibrillation was detected in the pregnant group during Holter monitoring. Shortening of the minimum P-wave duration leads to increased P-wave dispersion during pregnancy. In contrast to other pathologies with increased P-wave dispersion, paroxysmal atrial fibrillation is absent in pregnant women; this may be a result of the stable maximum P wavelength that is present during pregnancy.

Effects of chronic anabolic steroid treatment on tonic and reflex cardiovascular control in male rats

The aim of this study was to analyze the cardiovascular effects of chronic stanozolol administration in male rats. The rats were randomly assigned to one of three groups: (1) control (n=12), (2) chronic treatment with low dose of stanozolol (LD, n=18, 5 mg/kgweek) and; (3) treatment with high dose of stanozolol (HD, n=28, 20 mg/kgweek). Mean arterial pressure (MAP) was higher in both HD (128+/-2.2 mmHg) and LD (126+/-2.5 mmHg) than control (116+/-2 mmHg). The LD group showed an increase in cardiac output (control 121+/-2.5, LD 154+/-5.9 ml/min), whereas in the HD group total peripheral resistance increased (control 1.03+/-0.07, HD 1.26+/-0.07 mmHg/ml/min). Acute sympathetic blockade caused a similar decrease in MAP in all groups. In conscious rats, the baroreflex index for bradycardia (control -3.7+/-0.4, LD -2.0+/-0.1 beat/mmHg) and tachycardia (control -3.6+/-0.3, LD -4.7+/-0.2 beat/mmHg) responses changed only in the LD group. Cardiac hypertrophy was observed in both treated groups (P<0.05). In conclusion, hypertension with differential hemodynamic changes and alterations in the reflex control in heart rate is seen at different stanozolol doses, which may be important variables in the cardiovascular effects of anabolic steroids.

Comparison of the effects of tibolone and estrogen replacement therapy on echocardiographic basic cardiac functions in post-menopausal women: a randomized placebo controlled study

OBJECTIVES

This study is designed to investigate and compare the effects of synthetic steroid tibolone and HRT on systolic and diastolic heart functions in post-menopausal women.

METHODS

This prospective, randomized placebo controlled double blind study was conducted in a university clinic. Fifty-eight non-smoking, otherwise healthy post-menopausal women who did not receive any kind of HRT at least for 3 years within the onset of menopause were included in the study. The patients were randomly allocated to either 2.5 mg per day tibolone (OD, n = 18), daily combined 0.625 mg of conjugated estrogens 2.5 mg-1 of medroxy progesterone acetate pill (EP, n = 20) or a vitamin pill (n= 20) in a double blinded fashion. Their basic systolic and diastolic functions were investigated with HP Sonos-1000 echocardiography using standard positions and windows before and 6 months after the initiation of HRT.

RESULTS

Mean age, weight, length of post-menopausal period, heart rate, systolic and diastolic pressures were similar between the groups. At the initiation of the study all groups had similar echocardiographic measurements. However, at the end of 6 months, left ventricular end-systolic and -diastolic volumes were decreased significantly compared to pretreatment and placebo in both EP and OD treated groups. (55.5 +/- 18.4 and 53.7 +/- 19.1.8 ml; 109.9 +/-19.9 and 110.7 +/- 20.8 ml versus 74.5 +/- 14.9 and 142.7 +/- 19.1 ml, respectively; P < 0.05). Improvement in diastolic functions was significant in EP/OD groups compared to pre-treatment period and the placebo groups (E/A 1.34 +/- 0.1 and 1.38 +/- 0.1 versus 1.18 +/-.09, deceleration time 204 +/- 11.1 and 202.8 +/- 27.1 ms versus 237.6 +/- 26.9 ms, respectively). Besides increase in left ventricular mass adjusted for height, decrease in left ventricular relative wall thickness, and systemic vascular resistance were significant in EP and OD treated groups than placebo and the pre-treatment measurements. Although improved in both OD and EP groups, the changes in systolic and diastolic functions were significantly higher in the OD treated group. Based on our preliminary results, we may conclude that both EP and OD regimens may improve cardiac performance and age related dysfunctions.

CONCLUSION

The present results may further support that both OD and EP exert many direct effects on cardiovascular system other than metabolic changes regarding lipoproteins. The greater improvement in the OD group may be explained by its weak androgenic activity which is consistent with the in vitro data that androgens are potent relaxing agents on coronary arteries and restores cardiac myosin isoenzyme and ATPase patterns which mandates further clinical studies.

Is androgenic alopecia a result of endocrine effects on the vasculature?

Androgenic alopecia is a condition of concern for many patients. Though much has been learned about this condition, the exact pathophysiological mechanism is yet to be established. Currently most study concerning androgenic alopecia has focused on the effects of androgens on the pilosebaceous unit itself. An area of study that has received considerably less attention is that of androgens inducing baldness by indirect effects, that is, effects on tissues other than the pilosebaceous unit. In this paper, the author offers a novel hypothesis in which androgenic hair loss is mediated via the effects of androgens on the vasculature supplying the scalp. In this new hypothesis androgens effect anatomical changes in the vasculature of susceptible individuals, resulting in an environment in which hair growth is hindered and eventually ceases. The author discusses past studies demonstrating the effects of androgens on vessels and how these effects may relate to anatomical changes in the vasculature leading to hair loss. Also included is a discussion on future experimentation to test this new hypothesis.

Androgen contributes to gender-related cardiac hypertrophy and fibrosis in mice lacking the gene encoding guanylyl cyclase-A

Myocardial hypertrophy and extended cardiac fibrosis are independent risk factors for congestive heart failure and sudden cardiac death. Before age 50, men are at greater risk for cardiovascular disease than age-matched women. In the current studies, we found that cardiac hypertrophy and fibrosis were significantly more pronounced in males compared with females of guanylyl cyclase-A knockout (GC-A KO) mice at 16 wk of age. These gender-related differences were not seen in wild-type mice. In the further studies, either castration (at 10 wk of age) or flutamide, an androgen receptor antagonist, markedly attenuated cardiac hypertrophy and fibrosis in male GC-A KO mice without blood pressure change. In contrast, ovariectomy (at 10 wk of age) had little effect. Also, chronic testosterone infusion increased cardiac mass and fibrosis in ovariectomized GC-A mice. None of the treatments affected cardiac mass or the extent of fibrosis in wild-type mice. Overexpression of mRNAs encoding atrial natriuretic peptide, brain natriuretic peptide, collagens I and III, TGF-beta1, TGF-beta3, angiotensinogen, and angiotensin converting enzyme in the ventricles of male GC-A KO mice was substantially decreased by castration. The gender differences were virtually abolished by targeted deletion of the angiotensin II type 1A receptor gene (AT1A). Neither castration nor testosterone administration induced any change in the cardiac phenotypes of double-KO mice for GC-A and AT1A. Thus, we suggest that androgens contribute to gender-related differences in cardiac hypertrophy and fibrosis by a mechanism involving AT1A receptors and GC-A.

Hemodynamics of orthostatic intolerance: implications for gender differences

Women have a greater incidence of orthostatic intolerance than men. We hypothesized that this difference is related to hemodynamic effects on regulation of cardiac filling rather than to reduced responsiveness of vascular resistance during orthostatic stress. We constructed Frank-Starling curves from pulmonary capillary wedge pressure (PCWP), stroke volume (SV), and stroke index (SI) during lower body negative pressure (LBNP) and saline infusion in 10 healthy young women and 13 men. Orthostatic tolerance was determined by progressive LBNP to presyncope. LBNP tolerance was significantly lower in women than in men (626.8 +/- 55.0 vs. 927.7 +/- 53.0 mmHg x min, P < 0.01). Women had steeper maximal slopes of Starling curves than men whether expressed as SV (12.5 +/- 2.0 vs. 7.1 +/- 1.5 ml/mmHg, P < 0.05) or normalized as SI (6.31 +/- 0.8 vs. 4.29 +/- 0.6 ml.m-2.mmHg-1, P < 0.05). During progressive LBNP, PCWP dropped quickly at low levels, and reached a plateau at high levels of LBNP near presyncope in all subjects. SV was 35% and SI was 29% lower in women at presyncope (both P < 0.05). Coincident with the smaller SV, women had higher heart rates but similar mean arterial pressures compared with men at presyncope. Vascular resistance and plasma norepinephrine concentration were similar between genders. We conclude that lower orthostatic tolerance in women is associated with decreased cardiac filling rather than reduced responsiveness of vascular resistance during orthostatic challenges. Thus cardiac mechanics and Frank-Starling relationship may be important mechanisms underlying the gender difference in orthostatic tolerance.

Aortic dissection in pregnancy: analysis of risk factors and outcome

Aortic dissection during pregnancy is a life-threatening event. Recent studies have revealed similar histologic changes in the wall of the ascending aorta in patients with bicuspid aortic valve disease (BAVD). Based on a review of the literature, including the experience from two institutions, we looked at the patient's characteristics in patients with thoracic aortic dissection during pregnancy. We found that aortic root enlargement (> 4cm) or an increase of aortic root size during pregnancy in patients with BAVD, and Marfan syndrome is associated with a considerable risk for the occurrence of Type A dissection.

Androgens and coronary artery disease

A significant and independent association between endogenous testosterone (T) levels and coronary events in men and women has not been confirmed in large prospective studies, although cross-sectional data have suggested coronary heart disease can be associated with low T in men. Hypoandrogenemia in men and hyperandrogenemia in women are associated with visceral obesity; insulin resistance; low high-density lipoprotein (HDL) cholesterol (HDL-C); and elevated triglycerides, low-density lipoprotein cholesterol, and plasminogen activator type 1. These gender differences and confounders render the precise role of endogenous T in atherosclerosis unclear. Observational studies do not support the hypothesis that dehydroepiandrosterone sulfate deficiency is a risk factor for coronary artery disease. The effects of exogenous T on cardiovascular mortality or morbidity have not been extensively investigated in prospective controlled studies; preliminary data suggest there may be short-term improvements in electrocardiographic changes in men with coronary artery disease. In the majority of animal experiments, exogenous T exerts either neutral or beneficial effects on the development of atherosclerosis. Exogenous androgens induce both apparently beneficial and deleterious effects on cardiovascular risk factors by decreasing serum levels of HDL-C, plasminogen activator type 1 (apparently deleterious), lipoprotein (a), fibrinogen, insulin, leptin, and visceral fat mass (apparently beneficial) in men as well as women. However, androgen-induced declines in circulating HDL-C should not automatically be assumed to be proatherogenic, because these declines may instead reflect accelerated reverse cholesterol transport. Supraphysiological concentrations of T stimulate vasorelaxation; but at physiological concentrations, beneficial, neutral, and detrimental effects on vascular reactivity have been observed. T exerts proatherogenic effects on macrophage function by facilitating the uptake of modified lipoproteins and an antiatherogenic effect by stimulating efflux of cellular cholesterol to HDL. In conclusion, the inconsistent data, which can only be partly explained by differences in dose and source of androgens, militate against a meaningful assessment of the net effect of T on atherosclerosis. Based on current evidence, the therapeutic use of T in men need not be restricted by concerns regarding cardiovascular side effects. Available data also do not justify the uncontrolled use of T or dehydroepiandrosterone for the prevention or treatment of coronary heart disease.

Left ventricular diastolic function assessment by tissue Doppler echocardiography in relation to hormonal replacement therapy in postmenopausal women with diastolic dysfunction

The objective of this study was to evaluate the effect of hormone replacement therapy (HRT) regimens on left ventricular diastolic function by using mitral pulsed wave Doppler (MPWD) and tissue Doppler velocities (TDE). Seventy-eight postmenopausal women with normotensive and impaired diastolic left ventricular filling were included in the study. All the patients began a six-cycle HRT course. This formulation consisted of E2 valerate plus Medroxy progesterone acetate (MPA). Left ventricular diastolic function at rest was evaluated by M-mode, two-dimensional, MPWD and TDE in 78 postmenopausal women with normal blood pressure before the treatment for 6 months of HRT. The M-mode, two-dimensional, and MPWD parameters assessed were heart rate, systolic blood pressure, diastolic blood pressure, left ventricular mass index, ejection fraction of the left ventricle (EF), septal (IVS) and posterior wall (PW) thickness, left ventricular end-systolic (LVESD) and end-diastolic (LVEDD) diameter, left atrial diameter, peak early diastolic velocity (E), peak atrial velocity (A), E/A ratio, E acceleration time, E deceleration time, diastolic filling period, and isovolumic relaxation time (IVRT). The TDE parameters assessed were peak early diastolic velocity (E'), peak late diastolic velocity (A'), peak systolic velocity, E'/A' ratio, E' acceleration time, E' deceleration time, IVRT', and E/E' ratio. Quantitative data were analyzed using Student t test. Among the MPWD parameters, peak A velocity, E deceleration time, and IVRT significantly decreased, while peak E velocity and E/A ratio increased after a 6-month treatment. From the point of TDE parameters, E' velocity and E'/A' ratio increased, while A' velocity, E' deceleration time, E/E' ratio and IVRT' decreased. Some MPWD and TDE parameters were partially reversed after HRT. TDE velocities and especially E/E' ratio may provide better and true information of the diastolic function. TDE parameters were independent from the preload and did not produce pseudonormal pattern. HRT may cause increase in the blood volume and produce pseudonormal pattern in transmitral flow. In that case, TDE may be a beneficial method for evaluation of diastolic function.

Gender differences in the regulation of vascular tone

1. The greater incidence of hypertension and coronary artery disease in men and post-menopausal women compared with premenopausal women has suggested vascular protective effects of the female sex hormone oestrogen. However, vascular effects of the female sex hormone progesterone and the male sex hormone testosterone have also been suggested. 2. Oestrogen, progesterone and testosterone receptors have been identified in the plasmalemma, cytosol and nuclear compartments of vascular cells. The interaction of sex hormones with their specific receptors triggers not only long-term genomic vascular effects, but also acute non-genomic vascular responses. 3. Sex hormones may activate endothelium-dependent vascular relaxation pathways, including the nitric oxide-cGMP and prostacyclin-cAMP pathways and a hyperpolarizing factor pathway. 4. Sex hormones may also inhibit the mechanisms of vascular smooth muscle contraction, such as [Ca2+]i, protein kinase C and other protein kinases. 5. The sex hormone-induced stimulation of endothelium-dependent vascular relaxation and inhibition of vascular smooth muscle contraction may contribute to the gender differences in vascular tone and may represent potential beneficial vascular effects of hormone-replacement therapy during natural and surgically induced deficiencies of gonadal hormones.

Estrogen receptor expression and synthesis in the human internal thoracic artery

The inhibition of vascular smooth muscle cell proliferation is mediated through two intracellular estrogen receptors (ERs), ER-alpha and ER-beta. Deletion variants of ER-alpha have been decribed for cultures of smooth muscle cells. The internal thoracic artery is frequently used as coronary artery bypass graft, yet neither has it been studied for the expression of ER subtypes nor for the synthesis of the ERs in morphologically hetergeneous smooth muscle cells. Using nested RT-PCR, we have demonstrated the mRNA for ER-alpha splicing variants in intact human internal thoracic arteries. The 7A deletion variant occurred in 8 out of 12 cases, the full-length transcript in three cases. The full-length transcript was always found for the ER-beta. Immunolocalization revealed ER-positive nuclei in the desmin-positive subset of smooth muscle cells, but not in cytokeratin (CK)-positive cells of the thickened intima. Morphological evidence is presented suggesting that ER synthesis is high in the tunica media when cell proliferation of smooth muscle cells is increased. We conclude that, in internal thoracic arteries, the 7A deletion variant of ER-a occurs in 75%, whereas the full-length transcript is found in all cases. The significance remains unclear.

Vascular reactivity in hypogonadal men is reduced by androgen substitution

The effect of testosterone (T) substitution therapy on blood vessel functions in relation to cardiovascular disease has not been fully elucidated. In 36 newly diagnosed nonsmoking hypogonadal men (37.5 +/- 12.7 yr) endothelium-dependent flow-mediated vasodilatation (FMD; decreased in atherosclerosis) of the brachial artery was assessed before treatment and after 3 months of T substitution therapy (250 mg testosterone enanthate im every 2 wk in 19 men, human chorionic gonadotropin sc twice per week in 17 men). Twenty nonsmoking controls matched for age, low-density lipoprotein cholesterol (LDL-C), body height, and baseline diameter of the artery were selected for repeated measurements from a larger eugonadal control group (n = 113). In hypogonadal men, basal FMD (17.9 +/- 4.5%) was significantly higher than in the large (11.9 +/- 6.4%) and matched control (11.8 +/- 7.1%, both P < 0.001) groups. Grouped multiple linear regression analysis revealed a significant negative association of T levels with FMD within the hypogonadal range, but no significant association was seen within the eugonadal range. During substitution therapy, T levels increased from 5.8 +/- 2.3 to 17.2 +/- 5.1 nmol/liter and FMD decreased significantly to 8.6 +/- 3.1% (P < 0.001, analysis for covariance for repeated measurements including matched controls). LDL-C and advanced age contributed significantly to decrease FMD (P = 0.01, P = 0.04, respectively). Because T substitution adversely affects this important predictor of atherosclerosis, other contributing factors (such as smoking, high blood glucose, and LDL-C) should be eliminated or strictly controlled during treatment of hypogonadal men.

Nongenomic vasodilator action of progesterone on primate coronary arteries

In the present investigation, we test the hypothesis that progesterone can rapidly relax, via a nongenomic mechanism, persistent flow occluding, agonist-activated coronary artery (CA) vasospasm, and hyperreactive vascular muscle cell (VMC) Ca(2+) responses in ovariectomized rhesus monkeys. CA vasospasm, induced by injection of 100 microM serotonin and 1 microM U-46619 (5-HT+U; 1 ml/30 s), resulted in a decrease in CA diameter (phi) from 1.8 +/- 0.2 to 0.3 +/- 0.1 mm at the site of focal constriction. Injection of 100 ng progesterone into the CA significantly relieved the severe vasoconstriction (1.3 +/- 0.2 mm) and reestablished distal flow in 3 min; the preconstriction phi was completely restored in 8.2 +/- 2.6 min (n = 6). Similarly, cell impermeant albumin-conjugated progesterone, but not albumin-conjugated 17 beta-estradiol, decreased 5-HT+U stimulated VMC Ca(2+) responses (250 +/- 34% of basal 30 min after stimulation) back to the prestimulation level (113 +/- 17% of basal) in 25 min (half time = 7 min). The presence of a rapid vasodilator action of progesterone in the primate CA and isolated VMC suggests its benefits in hormone replacement therapy may also include nongenomic vascular relaxant actions.

Adaptation of cardiac morphology and function to endurance and strength training. A comparative study using MR imaging and echocardiography in males and females

Left ventricular (LV) dimensions and function and maximal oxygen uptake (VO(2)max) were measured in endurance-trained (10 male, m, 10 female, f), strength-trained athletes (8 m, 10 f) and untrained subjects (9 m, 10 f). LV dimensions were measured using magnetic resonance imaging (MRI) and echocardiography and the results were equal irrespective of method. Endurance-trained m and f had significantly higher LV volumes and mass than both strength-trained and controls. No VO(2)max or dimensional differences were seen between strength-trained and untrained subjects. In endurance-trained males, LV volumes and mass/kg bw were higher than in endurance-trained females. There was no significant gender difference for strength-trained or untrained subjects regarding body weight-related heart dimensions. It is concluded that LV dimensions and volumes are strongly dependent on oxygen transport capacity in normal subjects practising different modes of training, and that the gender differences, if LV dimensions are related to aerobic work capacity, are smaller than previously reported.

Evidence for progesterone receptors in the human fetoplacental vascular tree

The presence of progesterone receptors (PR) throughout the human term fetoplacental vascular tree was investigated. By reverse transcription-polymerase chain reaction (RT-PCR), we showed expression of PR mRNAs in stem villi vessels, chorionic arteries and veins, and umbilical arteries and veins. Binding studies and Scatchard analysis revealed a single class of high-affinity binding sites for (3)H-R5020 (promegestone) in cytosolic extracts of all placental vessels, with K(d) values in the range of 2.5-4 nM. High levels of PR were detected in placental vessels compared to other vascular tissues. Thus, maximum binding capacities of stem villi vessels, chorionic arteries and veins, and umbilical arteries and veins were 247 +/- 25, 377 +/- 58, 295 +/- 40, 371 +/- 118, and 672 +/- 144 fmol/mg protein, respectively. Endothelial cell elimination in chorionic arteries did not significantly modify the number of PR. RT-PCR and binding studies also assessed PR expression in cultured placental vascular smooth muscle cells isolated from stem villi vessels. All these data suggested that most of the PR of fetoplacental vessels were from the media. In conclusion, we report here the first evidence of the presence of PR in the muscular layer of human term fetoplacental vessels. This finding, together with the high progesterone concentrations in cord blood, suggests that the interactions between the PR and its ligand may play a role in the physiology and physiopathology of human fetoplacental vascularization.

Effects of a single dose of oral estrogen on left ventricular diastolic function in hypertensive postmenopausal women with diastolic dysfunction

OBJECTIVE

To evaluate the acute effects of a single dose of oral estrogen on left ventricular diastolic function in hypertensive postmenopausal women with diastolic dysfunction.

DESIGN

Prospective, double-blind, placebo-controlled, clinical study.

SETTING

Cardiology and postmenopausal outpatient clinics of a university hospital.

PATIENT(S)

Thirty postmenopausal women with hypertension (diastolic blood pressure of >90 mm Hg) and left ventricular diastolic dysfunction (mitral E/A ratio [the ratio of peak velocity of early mitral diastolic filling to late diastolic filling] of <1 and isovolumic relaxation time of >100 ms) were included in the study. Thirty normotensive postmenopausal women with normal left ventricular diastolic function served as the control group.

INTERVENTION(S)

Conjugated equine estrogen (0.625 mg) was given orally. Left ventricular diastolic function was assessed by Doppler echocardiography at baseline and 3 hours after the administration of estrogen.

MAIN OUTCOME MEASURE(S)

Left ventricular diastolic filling as assessed by Doppler echocardiography.

RESULT(S)

Estrogen had no effect on heart rate or blood pressure in either study group. The baseline E/A ratios were 0.72 +/- 0.26 and 1.22 +/- 0.30, and the isovolumic relaxation times were 122 +/- 18 ms and 89 +/-14 ms in the hypertensive and normotensive groups, respectively. Estrogen had no significant effect on any of the Doppler parameters in the normotensive group. In the hypertensive group, there was a trend toward normalization of the E/A ratio (from 0.73 +/- 0.11 to 0.84 +/- 20) and a significant improvement in the isovolumic relaxation time (from 124 +/- 20 ms to 105 +/- 13 ms) in response to the administration of estrogen compared with placebo.

CONCLUSION(S)

A single dose of oral estrogen caused a significant improvement in left ventricular diastolic filling in hypertensive postmenopausal women with diastolic dysfunction.

Supersensitivity to serotonin- and histamine-induced arterial contraction following ovariectomy

The modulating role of estrogens and ovariectomy on coronary artery and thoracic aortic rings was examined in female rabbits. Three treatment groups were studied: (1) control, (2) ovariectomy, and (3) ovariectomy + 17beta-estradiol acetate (40 microg/kg per day, i.m. for 7 days). Coronary artery reactivity was studied in the isolated retrogradely perfused heart. Aortic reactivity was studied using endothelium intact and denuded aortic rings. Concentration-response curves were performed to serotonin (5-HT) and histamine. A 21-fold, a 4.7-fold, and a 5.2-fold increase in sensitivity to 5-HT-induced contraction were observed in the ovariectomy group compared to the control group for coronary artery, intact aortic, and denuded aortic preparations, respectively (P < 0.05 for each comparison). Similarly, 34-fold, 4.9-fold, and 5.0-fold increases in sensitivity to histamine-induced contraction were observed in the ovariectomy group compared to control group for coronary artery, intact aortic, and denuded aortic preparations, respectively (P < 0.05 for each comparison). 17beta-Estradiol administration reversed the supersensitivity to serotonin- and histamine-induced vascular contraction observed following ovariectomy. No differences in EC50 or maximal contraction were noted between control and ovariectomy + estrogen groups. Baseline nitric oxide release and maximal 5-HT- and histamine-induced nitric oxide release from the perfused heart were decreased (P < 0.05) in ovariectomy rabbits compared to control and ovariectomy + estrogen treatment groups. The data demonstrate that (1) reduced autacoid-induced nitrous oxide release following ovariectomy and (2) direct effects upon the vascular smooth muscle contractility, which are probably mediated by altered receptor sensitivity by ovariectomy and estrogen replacement therapy. The information obtained from this study provides additional information regarding possible beneficial actions of estrogen replacement therapy in post-menopausal women.

The cardiac toxicity of anabolic steroids

Anabolic steroids are synthetic derivatives of testosterone that were developed as adjunct therapy for a variety of medical conditions. Today they are most commonly used to enhance athletic performance and muscular development. Both illicit and medically indicated anabolic steroid use have been temporally associated with many subsequent defects within each of the body systems. Testosterone is the preferred ligand of the human androgen receptor in the myocardium and directly modulates transcription, translation, and enzyme function. Consequent alterations of cellular pathology and organ physiology are similar to those seen with heart failure and cardiomyopathy. Hypertension, ventricular remodeling, myocardial ischemia, and sudden cardiac death have each been temporally and causally associated with anabolic steroid use in humans. These effects persist long after use has been discontinued and have significant impact on subsequent morbidity and mortality. The mechanisms of cardiac disease as a result of anabolic steroid use are discussed in this review.

Hemodynamic effect of 17 beta-estradiol in absence of NO in ovariectomized rats: role of angiotensin II

Previous reports correlate plasma levels of estrogen with increased nitric oxide (NO) production. To investigate whether the hemodynamic effects of estrogens are mediated by NO, we compared the hemodynamic changes induced by 17 beta-estradiol (100 micrograms/kg) in the absence and presence of the NO synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). All protocols were performed in ovariectomized, conscious rats. Estradiol alone resulted in no significant changes in cardiac index (CI) or mean arterial pressure (MAP). However, in the presence of L-NAME, estradiol induced a significant increase in total peripheral resistance (TPR) of 37.3 +/- 11.7% and a decrease in CI of 27 +/- 4.9%, without changes in MAP. Previous blockade of angiotensin II AT1 receptors with losartan prevented any change in CI and TPR induced by 17 beta-estradiol in the presence of L-NAME. These observations suggest that NO is necessary to offset a vasoconstrictor action of angiotensin II, which is stimulated by estradiol administration.

Cardiac myocytes and fibroblasts contain functional estrogen receptors

Gender-based differences found in cardiovascular diseases raise the possibility that estrogen may have direct effects on cardiac tissue. Therefore we investigated whether cardiac myocytes and fibroblasts express functional estrogen receptors. Immunofluorescence demonstrated estrogen receptor protein expression in both female and male rat cardiac myocytes and fibroblasts. Nuclear translocation of the estrogen receptor protein was observed after stimulation of cardiomyocytes with 17beta-estradiol (E2). Cells transfected with an estrogen-responsive reporter plasmid showed that treatment with E2 induced a significant increase in reporter activity. Furthermore, E2 induced a significant increase in expression of the estrogen receptors alpha and beta, progesterone receptor and connexin 43 in cardiac myocytes. Cardiac myocytes and fibroblasts contain functional estrogen receptors and estrogen regulates expression of specific cardiac genes. These data suggest that gender-based differences in cardiac diseases may in part be due to direct effects of estrogen on the heart.

Primary immunolocalization of androgen target cells in the human anterior cruciate ligament

To identify androgen target cells in the human anterior cruciate ligament, immunohistochemical localization of the androgen receptor was performed in 31 specimens of the ligament. All of the specimens were obtained at surgery. Seventeen specimens were from women, and 14 were from men: the average age of the patients was 45.2 years (range: 18-78 years). An immunoperoxidase method using monoclonal antibodies to the androgen receptor was employed to identify androgen target cells in the ligament. Consistent staining of the androgen receptor was demonstrable in six specimens obtained from young men 18-24 years old, and equivocal positive staining was seen in two other specimens from young men. No receptors were demonstrated by this method in any of the specimens from women or older men. Androgen receptors were localized to synoviocytes in the synovium and under the synovial lining, fibroblasts in the ligament stroma, and cells lining the blood-vessel walls of the anterior cruciate ligament. The demonstration of androgen receptors in the cells of the anterior cruciate ligament strongly suggests that male sex hormones may have an effect on the structure and composition of this ligament in young men.

Gender considerations in hypertension pathophysiology and treatment

Cardiovascular disease is the leading cause of death among women, yet clinical trials have not evaluated specific treatment strategies for women. Recently, there has been an expansion of scientific literature exploring differences between women and men with hypertension and cardiovascular disease. The cardioprotective effects of estrogen have been well demonstrated, and the loss of endogenous estrogens with aging contributes to the rapid increase in the incidence of coronary artery disease after menopause. Many of the adverse effects of estrogen deficiency are reversible with estrogen replacement. Estrogen improves lipoprotein profiles, has vasodilatory effects on the endothelium, and inhibits vascular smooth muscle cell growth and constriction. These effects likely all contribute to the reduction in coronary artery disease in the presence of estrogen, and the clinical benefits are not attenuated by concurrent progestins. There are gender-specific differences in the epidemiology of hypertension and coronary artery disease, as well as differences in the pathophysiology and clinical manifestations of disease. Given important experimental interactions between estrogens and the major classes of antihypertensive agents, as well as secondary benefits such as a possible reduction in bone loss with certain agents, a gender-specific approach to hypertension appears to be warranted. Future clinical trials will need to address gender-specific differences in treatment approaches.

Primary immunolocalization of estrogen and progesterone target cells in the human anterior cruciate ligament

To identify estrogen and progesterone target cells in the human anterior cruciate ligament immunohistochemical localization of both estrogen and progesterone receptors was performed in 17 specimens of human anterior cruciate ligament. All ligament specimens were obtained at surgery. Thirteen specimens were from women, and four were from men: the average age was 57 years (range, 18-78 years). Eleven specimens (from nine women and two men) came from total knee replacements for osteoarthritis of the knee: three (from two women and one man), from reconstructions of the anterior cruciate ligament: two (both from women), from medial meniscectomies; and one (from a man), from an amputation secondary to chondrosarcoma of the pelvis. An immunoperoxidase method using monoclonal antibodies to the estrogen and progesterone receptors was employed to identify estrogen and progesterone target cells in the anterior cruciate ligament. Staining of both receptors was demonstrable in 14 specimens and in the remaining three specimens less than 15% of the cells were stained. Both estrogen and progesterone receptors were localized to synoviocytes in the synovial lining, fibroblasts in the anterior cruciate ligament stroma and cells in the blood vessel walls of the ligament. This demonstration of receptors for estrogen and progesterone in the cells of anterior cruciate ligament suggests that female sex hormones may have an effect on its structure and composition.

Estrogen receptors in the cardiovascular system

Various direct effects of estradiol on arterial tissue suggest the presence of estrogen receptors (ER) in the vascular wall. The study of ER detection has made an important progress over the last 10 years with the advent and widespread use of monoclonal antibodies against the receptor protein. Using immunocytochemical methods and monoclonal antibodies, we have detected estrogen receptors in the tunica media of arteries from the reproductive tract; their concentration depends on the hormonal status. These receptors are apparently absent from saphenous veins (taken from patients undergoing surgical removal of varicose veins). We also document here results on the cardiovascular system we discuss their implications in blood vessel relaxation and cell proliferation.

Modulation of hypertensive heart disease by estrogen

Left ventricular hypertrophy is an independent risk factor for morbidity and mortality in patients with hypertensive heart disease. Cardiac hypertrophy, associated with increased cardiac fibrosis and myocardial relaxation impairment, shows gender-based differences with significantly higher mortality in men. The role of estrogen in the pathogenesis of this process is poorly understood. After our previous demonstration that cardiac myocytes and fibroblasts contain functional estrogen receptors, we therefore investigated: 1) the influence of different estrogen metabolites on cardiac fibroblast growth; 2) the influence of different estrogen metabolites on the expression of the immediate early gene c-Fos; 3) the influence of estrogen on the L-type calcium channel in cardiomyocytes.

METHODS

1) Neonatal rat cardiac fibroblasts were incubated with 17 beta-estradiol, estrone, 2-hydroxyestrone, and 2-methoxyestradiol (all 10(-9) M). Bromodeoxyuridine incorporation was measured after 24 h. 2) c-Fos expression was demonstrated by immunoblotting. 3) L-type (Ca2+) current with and without 17 beta-estradiol was assessed in adult guinea pig cardiomyocytes by whole cell patch clamp.

RESULTS

Cardiac fibroblast growth was stimulated by estrogen metabolites with 2-hydroxyestrone as the most potent activator; in addition, 10(-5) M 17 beta-estradiol reduced the L-type Ca2+ current by about 20% in cardiomyocytes.

CONCLUSIONS

Estrogen induces both short term effects (non-genomic) and long term effects (genomic) on the heart and may therefore account for gender- and age-based differences in hypertensive heart disease.

Estrogen and cardiovascular function after menopause

Nonrandomized trials of postmenopausal estrogen replacement have shown a benefit in the prevention of coronary artery disease. Less clear are the specific mechanisms by which this occurs. Estrogen has beneficial effects on the lipid profile, with significant elevations in high density lipoprotein cholesterol and reductions in low density lipoprotein cholesterol reported. Also, antioxidant properties have been ascribed to estrogen. In addition, estrogen has been shown to prevent paradoxic vasoconstriction in atherosclerotic coronary arteries after acetylcholine and may have calcium channel-blocking and alpha2-inhibiting properties. Other proposed mechanisms of cardiovascular protection include reductions in serum fibrinogen and increases in prostacyclin biosynthesis. There is some evidence that cardiovascular biomechanics may be mildly depressed after menopause and that estrogen may normalize these changes by increasing ventricular contractility and, possibly, relaxation. Far less is known about the cardiovascular effects of progesterone, but overall it does not appear that the less androgenic progestins substantially modify the effects of estrogen. Because more women > 50 years old die of cardiovascular disease than any other cause, further clinical investigations of the risks and benefits of estrogen replacement and combined estrogen and progesterone therapy are clearly needed.

The regulation of plasminogen activators and plasminogen activator inhibitor type 1 in endothelial cells by sex hormones

OBJECTIVE

The purpose of this study was to assess the effect of 17 beta-estradiol, progesterone, and testosterone on secretion of plasminogen activators and plasminogen activator inhibitor type 1 by cultured endothelial cells.

STUDY DESIGN

Bovine aortic endothelial cells were cultured in medium that contained 17 beta-estradiol, progesterone, or testosterone at various concentrations (10(-13) to 10(-6) mol/L). Plasminogen activator activity in culture medium in the presence of cells was assayed after a 36-hour incubation using chromogenic substrate and iodine 125-labeled fibrin plate assays. Plasminogen activator inhibitor type 1 antigen was detected in conditioned media of bovine aortic endothelial cells by Western blotting analysis.

RESULTS

All three steroid hormones exhibited biphasic dose-response effects, characterized by stimulation of plasminogen activator secretion at lower concentrations and inhibition of plasminogen activator secretion at higher concentrations. A significant stimulatory effect on plasminogen activator secretion (74% over control) was observed at a 17 beta-estradiol concentration of 10(-12) mol/L (p < 0.03). At higher concentrations of 17 beta-estradiol, progesterone, and testosterone, inhibition of plasminogen activator secretion was observed (p < 0.05). Decreased levels of plasminogen activator inhibitor type 1 antigen were detected in supernatants treated with either 17 beta-estradiol or progesterone at a concentration of 10(-12) mol/L and were maximal at 10(-7) mol/L 17 beta-estradiol, progesterone, and testosterone.

CONCLUSION

The secretion of plasminogen activators and plasminogen activator inhibitor type 1 is regulated in a biphasic dose-dependent manner by sex hormones in bovine aortic endothelial cells.

Arterial dissections associated with pregnancy

Two cases of spontaneous arterial dissection occurring in young, multiparous women shortly after delivery of uncomplicated pregnancies are described. Histologic analysis of arterial tissue samples obtained in both cases at points near and remote from the dissection sites shows evidence of significant arterial degeneration and loss of integrity, with changes similar to those observed in pregnant women, women using oral contraceptives, and animals given female sex hormones. The types of arterial lesions associated with pregnancy and their sites of predilection and the etiologic roles of the hemodynamic stresses of pregnancy and hormones are discussed.

Acute effects of 17 beta-estradiol on the rat heart

OBJECTIVE

Our purpose was to study the acute effects of 17 beta-estradiol on mechanical and electrical activities of cardiac function and on coronary arteries in the rat heart.

STUDY DESIGN

The effects of 17 beta-estradiol were studied on perfused working heart isolated from Charles River male rats. Heart rates, coronary flow, aortic flow, and left ventricular pressure were measured. To avoid coronary interaction, chronotropic and inotropic effects were also tested on isolated atria. Data were analyzed with the paired Student t test.

RESULTS

17 beta-Estradiol produced a dose-dependent negative chronotropic effect in right atria but did not affect the contractility of left atria. A decrease in heart rate was also observed in perfused hearts treated with 5 x 10(-6) mol/L 17 beta-estradiol. 17 beta-Estradiol (5 x 10(-6) mol/L) significantly increased coronary flow (p < 0.005) but had a negligible effect on cardiodynamic index values. A significant effect of 17 beta-estradiol on cardiac function was observed when coronary arteries were precontracted with acetylcholine.

CONCLUSION

Both the experimental coronary vasodilatory effect and the negative chronotropic effect of 17 beta-estradiol support the clinical observations that suggest that this hormone may have an important role in prevention of cardiovascular diseases.

Human vascular smooth muscle cells contain functional estrogen receptor

BACKGROUND

The decreased incidence of coronary artery disease observed in postmenopausal women given estrogen (E2) replacement demonstrates an atheroprotective effect of E2 that is generally believed to be mediated by indirect, E2-induced changes in cardiovascular risk factor profiles. We hypothesized that the atheroprotective effect of E2 may be in part mediated by a direct effect of E2 on vascular smooth muscle cells (VSMCs). Therefore, a series of experiments was performed to determine whether human VSMCs contain a competent E2 receptor, a ligand-activated transcription factor known to mediate E2-induced effects in nonvascular cells.

METHODS AND RESULTS

Ribonuclease protection assays, with a probe derived from the human E2 receptor, were used to demonstrate E2-receptor mRNA in human saphenous vein VSMCs. To show that VSMCs contain E2-receptor protein as well as message, immunoblotting and immunofluorescence studies with a monoclonal anti-E2-receptor antibody were performed, and E2-receptor protein was detected by both methods. Transient transfection assays using a specific E2-responsive reporter system were used next to determine whether the VSMC E2 receptor is capable of E2-induced transcriptional transactivation. Initial studies using mammary artery-derived VSMCs resulted in a 2.4-fold increase in reporter activity in response to 10(-7) mol/L E2. Subsequent studies using saphenous vein VSMCs demonstrated increasing levels of reporter activation as the concentration of E2 was increased from 10(-9) mol/L (1.3-fold increase; SEM, 0.07; P = .05, n = 3) to 10(-7) mol/L (1.6-fold increase; SEM, 0.04; P = .002, n = 6). The specificity of the E2-induced transactivation of the reporter gene was shown by dose-dependent inhibition of transactivation by the pure E2 antagonist ICI 164,384 and by enhancement of the transactivation by simultaneous overexpression of the E2 receptor.

CONCLUSIONS

We have demonstrated for the first time that human VSMCs express E2-receptor mRNA and protein and that the E2 receptor in VSMCs is capable of estrogen-dependent gene activation. These data suggest a mechanism by which estrogen may directly alter VSMC function.