Cardiovascular disease in postmenopausal women

Role of exercise training in cardiovascular autonomic dysfunction and mortality in diabetic ovariectomized rats

Diabetes and menopause markedly increase the risk of cardiovascular disease in women. The objective of the present study was to investigate the effects of exercise training on cardiovascular autonomic dysfunction and on total mortality in diabetic female rats undergoing ovarian hormone deprivation. Female Wistar rats were divided into ovariectomized groups: sedentary and trained controls and sedentary and trained diabetic rats (streptozotocin, 50 mg/kg IV). Trained groups were submitted to an exercise training protocol on a treadmill (8 weeks). The baroreflex sensitivity was evaluated by heart rate responses to arterial pressure changes. Heart rate variability was determined using the SD of the basal heart rate. Vagal and sympathetic tonus were evaluated by pharmacological blockade. Diabetes impaired baroreflex sensitivity ( approximately 55%), vagal tonus ( approximately 68%), and heart rate variability ( approximately 38%). Exercise training improved baroreflex sensitivity and heart rate variability in control and diabetic groups in relation to their sedentary groups. Trained control rats presented increased vagal tonus compared with that of sedentary ones. The sympathetic tonus was reduced in the trained diabetic group as compared with that of other studied groups. Significant correlations were obtained between heart rate variability and vagal tonus with baroreflex sensitivity. Mortality, assessed during the training period, was reduced in trained diabetic (25%) rats compared with mortality in sedentary diabetic rats (60%). Together, these findings suggest that decreases in baroreflex sensitivity and heart rate variability may be related to increased mortality in female diabetic subjects and that improved autonomic regulation induced by exercise training may contribute to decreased mortality in this population.

Positive effects on cardiovascular and breast metabolic markers of oral estradiol and dydrogesterone in comparison with transdermal estradiol and norethisterone acetate

OBJECTIVES

To assess differences in two sequential combined hormone replacement therapy (HRT) products on selected cardiovascular and breast metabolic markers. The products were different concerning the route of administration of estradiol and its combined progestin, either oral or transdermal, and the androgenic properties of progestogens, respectively, dydrogesterone and norethisterone acetate.

METHODS

One hundred and nineteen healthy non-hysterectomized postmenopausal women were included in this open, multi-center, two parallel group trial. They were randomized to a treatment of six 28-day cycles with oral estradiol sequentially combined with dydrogesterone (oE2/D10) or a sequential combination patch of estradiol plus norethisterone acetate (tdE/NETA). At baseline and after six cycles the high-density lipoprotein cholesterol (HDL-C), the sex hormone binding globulin (SHBG) and the total insulin-like growth factor-I (IGF-I) blood levels were determined by a central laboratory. A total of 89 women were compliant to the protocol.

RESULTS

After six cycles, a statistically significant difference (P<0.001) concerning HDL-C, SHBG and IGF-I levels was found between the two treatment groups. The HDL-C levels were increased in the oE2/D10 group and decreased in the tdE/NETA group, with a final difference of about 0.3 mmol/l. The oE2/D10 treatment induced a sharp increase (about 57 mmol/l) in SHBG levels. IGF-I levels decreased with both the products, but the difference in favor of the oE2/D10 treatment was of about 30 ng/ml. Moreover, patients on tdE/NETA with an IGF-I baseline value below the median showed an increase.

CONCLUSION

Oral estradiol sequentially combined with dydrogesterone, a non-androgenic progestogen, induced positive changes of some cardiovascular (HDL-C) and breast (SHBG and IGF-I) metabolic markers. These effects were significantly different from those obtained with a transdermal estradiol associated to an androgenic progestogen.

Sex differences and the effects of sex hormones on hemostasis and vascular reactivity

Thrombus formation and vasospasm are involved in the initiation of acute ischemic events in the heart. Gender differences in persons with coronary artery disease and the incidence of myocardial ischemia have been clearly documented. In addition, it is well established that sex hormones influence the risk of developing coronary artery disease. Epidemiologic studies suggest that estrogen may exert a protective effect, yet the results of recently completed and ongoing prospective trials of estrogen and hormone (estrogen + progesterone) replacement suggest that these hormones can increase thrombotic events in postmenopausal women. This review focuses on sex (gender) differences in hemostasis and vascular reactivity and on the influence that sex hormones have on these physiologic systems. This review takes the novel approach of focusing on sex differences in hemostasis and vascular reactivity in healthy premenopausal women and men of a similar age. By comparing men and women in this age group, the confounding issues of age, pathology, or decline in sex hormone levels are avoided. Animal and in vitro investigations pertinent to examining potential cellular mechanism(s) of sex hormones in mediating these sex differences are discussed. We assume there is a relationship between the normal physiologic and pathologic effects of sex hormones; elucidating sex differences in normal cardiovascular function will help clarify the basis for sex differences in the incidence and manifestations of coronary heart disease and will aid in the future development of gender-specific therapies for cardiovascular disease.

Effects of hormonal replacement therapy in postmenopausal hypertensive patients

OBJECTIVE

To evaluate the effect of hormonal replacement therapy (HRT) on blood pressure (BP) in postmenopausal hypertensive women.

METHODS

Sixty women affected by hypertension were enrolled and randomized in two groups of treatment: transdermal continuous HRT in a sequential regimen (group A) and placebo (group P). At baseline, after 3 and 6 months of treatment, the BP with standard sphygmomanometer and with 24-h ambulatory recording method was evaluated in two periods (from day 10 through day 16 of the cycle and from day 20 through day 27 of the cycle). At the same time, we also evaluated total cholesterol, LDL-c, HDL-c, triglycerides, and fibrinogen levels.

RESULTS

After 3 and 6 months of treatment, no significant variations of systolic and diastolic BP measured with standard sphygmomanometer were detected in both groups. On the contrary, in group A in comparison with basal values and group P, and without difference between the two phases of treatment, the 24-h recording showed a significant (P<0.05) decrease in BP. No significant variations were detected in group P versus baseline. In particular, we observed in group A at 3 months of treatment a significant (P<0.05) decrease only in daytime BP in comparison with basal values and group P, without difference between the two phases of treatment. Indeed, the decrease in daytime BP was significant (P<0.05) for both systolic and diastolic BP. At 3 and 6 months a significant (P<0.05) decrease in total cholesterol, LDL-c and fibrinogen levels was detected in group A versus baseline and group P. HDL-c and triglyceride concentrations showed no significant variations.

CONCLUSIONS

The transdermal HRT induces a significant reduction of BP values and a favorable metabolic action in postmenopausal hypertensive patients.

Effects on serum lipid profiles of continuous 17beta-estradiol, intermittent norgestimate regimens versus continuous combined 17beta-estradiol/norethisterone acetate hormone replacement therapy

OBJECTIVE

To compare the effects of a daily oral 1-mg dose of continuous 17beta-estradiol (E2) plus intermittent (3 days off, 3 days on) norgestimate (NGM) 90 microg (n = 221), an oral 2-mg dose of continuous E2 plus intermittent NGM 180 microg (n = 219), and an oral 2-mg dose of continuous E2 plus continuous norethisterone acetate (NETA) 1 mg (n = 217) on blood lipids and lipoproteins in postmenopausal women.

BACKGROUND

The present study was undertaken because some progestins have adverse effects on lipid profiles, thereby negating the favorable effects of estrogens.

METHODS

This was a multicenter, randomized, parallel-group trial that focused primarily on the 2 marketed regimens--E2 1 mg/NGM 90 microg and E2/NETA. Both subjects and investigators were blinded to the intermittent regimens; the continuous combined regimen was administered open-label. After a minimum 12-hour overnight fast, blood samples were collected at baseline and during months 7 and 12 to determine lipid and lipoprotein concentrations using validated methods.

RESULTS

E2 1 mg/NGM 90 microg was associated with significant (ie, the 95% CI did not include 0) increases in high-density lipoprotein cholesterol (HDL-C) (6.8% [95% CI = 4.7%, 9.0%] and 4.8% [2.3%, 7.2%] at months 7 and 12, respectively) and high-density lipoprotein 2 cholesterol (HDL2-C) (10.8% [6.2%, 15.3%] and 24.1% [18.9%, 29.4%]) concentrations, and decreases in total cholesterol (-7.7% [-9.0%, -6.3%] and -9.2% [-10.5%, -7.9%]), low-density lipoprotein cholesterol (-14.3% [-16.3%, -12.4%] and -14.9% [-16.7%, -13.2%]), and lipoprotein(a) (-30.6% [-41.4%, -20.0%] at month 12) concentrations. A significant difference (P < 0.001 by analysis of variance) between the E2 1-mg/NGM 90-microg and NETA regimens was seen for HDL-C and HDL2-C concentrations, which were elevated in subjects receiving E2 1 mg/NGM 90 microg but reduced (-9.1% [-11.1%, -7.1%] and -12.3% [-14.3%, -10.3%] for HDL-C at months 7 and 12, respectively; -14.2% [-18.0%, -10.4%] and -2.5% [-7.8%, +2.8%] for HDL2-C at months 7 and 12, respectively) in those receiving E2/NETA.

CONCLUSIONS

In the present study, continuous E2 1 mg/NGM 90 microg was associated with beneficial effects on lipids and lipoproteins in healthy postmenopausal women, effects that were greater at least for HDL-C and HDL2-C than those observed with continuous combined E2/NETA. The applicability of the study results to women with preexisting cardiovascular disease or dyslipidemia, or those who are overweight, remains to be investigated.

A novel intermittent regimen of norgestimate to preserve the beneficial effects of 17beta-estradiol on lipid and lipoprotein profiles

OBJECTIVE

This study was undertaken to evaluate the effects of 3 dosage levels of intermittent norgestimate plus a constant dose of 17beta-estradiol on blood lipid and lipoprotein concentrations in 236 postmenopausal women.

STUDY DESIGN

In this multicenter, double-blind, parallel-group trial the subjects were randomly assigned to receive 1 mg estradiol daily or 1 mg estradiol daily plus intermittent (3 days off and 3 days on) doses of 30 microg, 90 microg, or 180 microg norgestimate for 360 days.

RESULTS

The regimens of 1 mg estradiol plus 30 microg norgestimate and 1 mg estradiol plus 90 microg norgestimate increased concentrations of high-density lipoprotein cholesterol, HDL(2) high-density lipoprotein cholesterol, HDL(3) high-density lipoprotein cholesterol (except the regimen of 1 mg estradiol plus 30 microg norgestimate at 7 months), and apolipoprotein apo A-I. They decreased total cholesterol concentration, low-density lipoprotein cholesterol concentration, low-density lipoprotein/high-density lipoprotein ratio, apolipoprotein apo B concentration, and Lp(a) lipoprotein concentration, and they attenuated estradiol-induced increases in triglyceride concentrations. In contrast, the regimen of 1 mg estradiol plus 180 microg norgestimate reduced concentrations of high-density lipoprotein cholesterol, high-density lipoprotein HDL(3) cholesterol, and apolipoprotein apo A-I at 7 months and increased the low-density lipoprotein/high-density lipoprotein ratio at 7 months.

CONCLUSIONS

An intermittent regimen of norgestimate at 30 or 90 microg daily administered for 3 days off followed by 3 days on preserved the beneficial lipid and lipoprotein changes induced by continuous therapy with 1 mg 17beta-estradiol daily; however, 180 microg norgestimate did not do so.