Annals of the New York Academy of Sciences
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Ann. N. Y. Acad. Sci. · Dec 2006
ReviewHormone replacement therapy and cardioprotection: what is good and what is bad for the cardiovascular system?
The incidence of cardiovascular diseases (CVDs) increases after menopause and at any age postmenopausal women have a significantly higher incidence of CVD compared to premenopausal women. Several epidemiological findings suggest the causative pathogenetic role of ovarian hormone deficiency in the development of CVD in women. Ovarian hormones have several potential protective effects on the cardiovascular system and despite several observational studies have shown the beneficial effect of estrogens and estrogen/progestin associations on CVD, at the present, after the findings of randomized studies, the effect of hormone replacement therapy (HRT) in the prevention of CVD is still under debate. ⋯ In early postmenopausal women, like the ones included in the observational studies, ovarian hormone replacement may be cardioprotective because of the responsiveness of the endothelium to estrogens that also buffer the detrimental effects upon coagulation. In late postmenopausal women ovarian hormones have either a null effect or even a detrimental effect because of the predominance of the procoagulant or plaque-destabilizing effects over the vasoprotective effects. Therefore, HRT has beneficial cardiovascular effects in younger women while it may have detrimental effect on coagulative balance and vascular inflammation and has little effect on cardiovascular functions in older women.
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During adolescence the brain shows remarkable changes in both structure and function. The plasticity exhibited by the brain during this pubertal period may make individuals more vulnerable to perturbations, such as stress. Although much is known about how exposure to stress and stress hormones during perinatal development and adulthood affect the structure and function of the brain, relatively little is known about how the pubertal brain responds to stress. ⋯ The purpose of this review is to present what is currently known about the pubertal maturation of the hypothalamic-pituitary-adrenal (HPA) axis, the neuroendocrine axis that mediates the stress response, and discuss what is currently known about how stressors affect the adolescent brain. Our dearth of knowledge regarding the effects of stress on the pubertal brain will be discussed in the context of our accumulating knowledge regarding stress-induced neuronal remodeling in the adult. Finally, as the adolescent brain is capable of such profound plasticity during this developmental stage, we will also explore the possibility of adolescence as a period of interventions and opportunities to mitigate negative consequences from earlier developmental insults.