Effects of withdrawal of chronic estrogen therapy on brachial artery vasoreactivity in women with coronary artery disease

Discontinuation of hormone replacement therapy after myocardial infarction and short term risk of adverse cardiovascular events: nationwide cohort study

OBJECTIVE

To assess the risk of adverse cardiovascular events in women who discontinue hormone replacement therapy after myocardial infarction compared with those who continue.

DESIGN

Nationwide register based cohort study.

SETTING

All hospitals in Denmark.

POPULATION

All 3322 women aged 40 years or over who survived 30 days after a myocardial infarction and were prescribed hormone replacement therapy at the time of myocardial infarction in the period 1997 to 2008.

MAIN OUTCOME MEASURES

Reinfarction, cardiovascular mortality, and all cause mortality 30 to 360 days after discharge.:

RESULTS

A total of 282 (8.5%) women had a reinfarction, 218 (6.6%) died of cardiovascular causes, and 357 (10.7%) died of any cause during follow-up. Women who discontinued overall hormone replacement therapy in the first year after myocardial infarction did not have a significantly different risk of reinfarction (hazard ratio 0.90, 95% confidence interval 0.68 to 1.19), cardiovascular mortality (1.21, 0.90 to 1.62), or all cause mortality (1.22, 0.97 to 1.53) than women who continued use. However, discontinuation of vaginal oestrogen was associated with a lower risk of reinfarction (hazard ratio 0.54, 0.34 to 0.86).

CONCLUSION

No certain conclusions can be drawn regarding increased or decreased risk of adverse cardiovascular events with continuing hormone replacement therapy after myocardial infarction. The results rule out neither a modest benefit nor a worrisome increase in risk. These figures may be valuable when a possible cardiovascular risk of hormone replacement therapy needs to be balanced with menopausal symptoms for the individual patient.

Role of aging versus the loss of estrogens in the reduction in vascular function in female rats

Although aging is known to lead to increased vascular stiffness, the role of estrogens in the prevention of age-related changes in the vasculature remains to be elucidated. To address this, we measured vascular function in the thoracic aorta in adult and old ovariectomized (ovx) rats with and without immediate 17beta-estradiol (E2) replacement. In addition, aortic mRNA and protein were analyzed for proteins known to be involved in vasorelaxation. Aging in combination with the loss of estrogens led to decreased vasorelaxation in response to acetylcholine and sodium nitroprusside, indicating either smooth muscle dysfunction and/or increased fibrosis. Loss of estrogens led to increased vascular tension in response to phenylephrine, which could be partially restored by E2 replacement. Levels of endothelial nitric oxide synthase and inducible nitric oxide synthase did not differ among the groups, nor did total nitrite plus nitrate levels. Old ovx exhibited decreased expression of both the alpha and beta-subunits of soluble guanylyl cyclase (sGC) and had impaired nitric oxide signaling in the vascular smooth muscle. Immediate E2 replacement in the aged ovx prevented both the impairment in vasorelaxation, and the decreased sGC receptor expression and abnormal sGC signaling within the vascular smooth muscle.

Hormone therapy and antioxidant vitamins do not improve endothelial vasodilator function in postmenopausal women with established coronary artery disease: a substudy of the Women's Angiographic Vitamin and Estrogen (WAVE) trial

We measured flow-mediated dilation (FMD) by high-resolution brachial ultrasound in 61 women who participated in the Women's Angiographic Vitamin and Estrogen (WAVE) trial, a randomized controlled trial. There were no significant differences in the baseline demographics of women receiving hormone therapy (0.625 mg/day of conjugated equine estrogen plus 2.5mg of medroxyprogesterone acetate for women who had not had a hysterectomy) or placebo; or vitamins (400 IU of Vitamin E and 500 mg of Vitamin C twice daily) or placebo. Baseline FMD was impaired in all subjects (3.3+/-7.6%). Neither hormone therapy (4.1+/-5.2% at baseline, 4.2+/-5.0% at 3 months, and 4.1+/-6.5% at 34 months) nor antioxidant vitamins (3.0+/-8.3% at baseline; 3.5+/-4.6% at 3 months; 3.1+/-7.6% at 34 months) improved FMD (all p-values=NS). Endothelium-independent vasodilation, induced by nitroglycerin (NTG) was similar at baseline and was not affected by either therapy. In univariate and multivariate analysis, neither hormone therapy nor antioxidant vitamins were associated with FMD. Women with established coronary artery disease have impaired flow-mediated vasodilation of the brachial artery that does not improve after 3 months or up to 34 months of treatment with postmenopausal hormone therapy or antioxidant vitamins.

Neuroendocrinology of female aging

BACKGROUND

Because the average human life span has increased, a greater part of more women's lives will be lived in a hypoestrogenic state.

OBJECTIVE

This article provides an overview of our current knowledge of the neuroendocrine processes in the aging female brain.

METHODS

Using the search terms cardiovascular disease, cognition, dementia, depression, estrogens, female aging, gonadotropins, immune function, mood, neuroendocrinology, neurotransmitters, osteoporosis, and ovarian steroids, a review of English-language literature on the MEDLINE database was conducted from 1970 through June 2004.

RESULTS

It is thought that the temporal patterns of neural signals are altered during middle age, leading to cessation of reproductive cycles, and that the complex interplay of ovarian and hypothalamic/pituitary pacemakers becomes increasingly dysfunctional with aging, ultimately resulting in menopause. Estrogen deficiency is associated with low mood, whereas estrogen therapy tends to be linked with improvements in measures of well-being and a decline in depression scores. It is likely that these effects of estrogens are mediated through changes in the metabolism of serotonin and nor epinephrine. Evidence exists to support the role of estrogens in specific effects on cognitive functioning in women, enhancing aspects of verbal memory, abstract reasoning, and information processing. Significant gender dimorphism is evident in both humoral and cell-mediated immune responses. The effects of estrogens on the cardiovascular system are complex; recent evidence suggests a negative role for oral estrogen in primary and secondary prevention of cardiovascular events. Additionally, estrogens increase the risk of stroke, and estrogen deficiency influences the pathogenesis of osteoporosis in both men and women.

CONCLUSIONS

Changes in the neuroendocrine system due to the loss of ovarian function at menopause have an important biological role in the control of reproductive and nonreproductive functions, and regulate mood, memory, cognition, behavior, immune function, the locomotor system, and cardiovascular functions. More detailed insights are needed into the complex mechanisms of neuroendocrine alterations with aging.

Effect of endogenous estrogen on endothelial function in women with coronary heart disease and its mechanism

BACKGROUND

Estrogen promotes and modulates vascular endothelial function, which may be protective against development of atherosclerosis. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, has been reported to be associated with the impairment of vascular endothelial function. Recent studies suggested estrogen replacement therapy lowers plasma concentrations of ADMA in healthy postmenopausal women. However, the relation between endogenous estrogen and ADMA and their effect on endothelial function in patients with coronary heart disease (CHD) remains unclear.

METHODS

Flow-mediated dilatation (FMD) and nitroglycerin-induced dilatation (NID) of the brachial arteries were detected by using high-resolution ultrasound in 33 women with CHD and 17 healthy controls. Plasma estradiol, ADMA, and lipid concentrations were also measured in all subjects.

RESULTS

In comparison with control group, FMD and NID were significantly decreased in the CHD group (1.73 +/- 1.26% vs. 5.37 +/- 3.20%, p < 0.001 and 12.38 +/- 6.70% vs. 20.79 +/- 7.57%, p < 0.01, respectively). Plasma estradiol concentrations in the CHD group were lower than in controls (27.80 +/- 12.28 vs. 43.83 +/- 14.30 pg/ml, p < 0.01), whereas ADMA concentrations in the CHD group were higher than in controls (3.39 +/- 1.07 vs. 1.31 +/- 0.69 micromol/l, p < 0.001). Pearson correlation analysis determined that plasma estradiol concentrations were associated with FMD, NID, age, systolic pressure, diastolic pressure and ADMA (r = 0.610, p < 0.01; r = 0.392, p < 0.01; r = -0.589, p < 0.01; r= -0.364, p < 0.01; r = -0.350, p < 0.05; r = -0.553, p < 0.01; respectively). Multiple linear stepwise regression analysis revealed that plasma estradiol concentrations was independently positively correlated with FMD (p < 0.005) and negatively correlated with ADMA (p < 0.05).

CONCLUSIONS

Both FMD and NID are impaired in women with CHD. The decrease of endogenous estrogen concentrations and the increase of ADMA concentrations may involve the endothelial dysfunction in women with CHD.

Endocrine withdrawal syndromes

Hypersecretion of endogenous hormones or chronic administration of high doses of the same hormones induces varying degrees of tolerance and dependence. Elimination of hormone hypersecretion or discontinuation of hormone therapy may result in a mixed picture of two syndromes: a typical hormone deficiency syndrome and a generic withdrawal syndrome. Thus, hormones with completely different physiological effects may produce similar withdrawal syndromes, with symptoms and signs reminiscent of those observed with drugs of abuse, suggesting shared mechanisms. This review postulates a unified endocrine withdrawal syndrome, with changes in the hypothalamic-pituitary-adrenal axis and the central opioid peptide, in which noradrenergic and dopaminergic systems of the brain act as common links in its pathogenesis. Long-term adaptations to hormones may involve relatively persistent changes in molecular switches, including common intracellular signaling systems, from membrane receptors to transcription factors. The goals of therapy are to ease withdrawal symptoms and to expedite weaning of the patient from the hormonal excess state. Clinicians should resort to the fundamentals of tapering hormones down over time, even in the case of abrupt removal of a hormone-producing tumor. In addition, the prevention of stress and concurrent administration of antidepressants may ameliorate symptoms and signs of an endocrine withdrawal syndrome.

Elevated C-reactive protein levels are associated with endothelial dysfunction in chronic cocaine users

OBJECTIVE

To examine the relationship of the serum C-reactive protein (CRP) and endothelial function and their associations with coronary artery calcification, lipid profile and cardiac changes.

METHODS

The analyses for serum lipids and CRP, echocardiography, spiral computed tomography scans and endothelial function assay were performed in 53 participants with a history of chronic cocaine use.

RESULTS

There were no statistically significant differences in demographic characteristics and drug use between CRP normal (<1.9 mg/l) and abnormal groups. The brachial artery diameter percentage changes in the third scan (immediately after deflation of cuff) and the fourth scan (90 s after deflation of cuff) were significantly associated with the CRP levels (the third: beta=-0.054, S.E.=0.027; P=0.028; the fourth: beta=-0.065, S.E.=0.026; P=0.016). The multiple regression models showed that CRP was the only significant predictor of artery diameter changes (%) in these two scans. The CRP abnormal group had more coronary artery calcification (calcium scores >5, 16.7 vs. 0%; P=0.036) and more cardiac diastolic dysfunction expressed as deceleration time >240 ms (16.7 vs. 0%; P=0.036).

CONCLUSIONS

Elevated serum CRP levels are associated with endothelial dysfunction, coronary artery calcification and cardiac diastolic dysfunction in chronic cocaine users.

Association between C-reactive protein, anti-Chlamydia pneumoniae antibodies, and vascular function in healthy adults

Abnormalities of vascular function occur in patients with risk factors for atherosclerosis before the development of obstructive disease. Our pilot data suggest that elevated serum markers of infection and/or inflammation are associated with functional abnormalities of the vasculature in subjects at otherwise low risk for atherosclerosis.