Abstract-Female gender and estrogen-replacement therapy in postmenopausal women are associated with improved heart failure survival, and physiological replacement of 17␤-estradiol (E2) reduces infarct size and cardiomyocyte apoptosis in animal models of myocardial infarction (MI). Here, we characterize the molecular mechanisms of E2 effects on cardiomyocyte survival in vivo and in vitro. Ovariectomized female mice were treated with placebo or physiological E2 replacement, followed by coronary artery ligation (placebo-MI or E2-MI) or sham operation (sham) and hearts were harvested 6, 24, and 72 hours later. After MI, E2 replacement significantly increased activation of the prosurvival kinase, Akt, and decreased cardiomyocyte apoptosis assessed by terminal deoxynucleotidyltransferase dUTP nick-end labeling (TUNEL) staining and caspase 3 activation. In vitro, E2 at 1 or 10 nmol/L caused a rapid 2.7-fold increase in Akt phosphorylation and a decrease in apoptosis as measured by TUNEL staining, caspase 3 activation, and DNA laddering in cultured neonatal rat cardiomyocytes. The E2-mediated reduction in apoptosis was reversed by an estrogen receptor (ER) antagonist, ICI 182,780, and by phospho-inositide-3 kinase inhibitors, LY294002 and Wortmannin. Overexpression of a dominant negative-Akt construct also blocked E2-mediated reduction in cardiomyocyte apoptosis. These data show that E2 reduces cardiomyocyte apoptosis in vivo and in vitro by ER-and phospho-inositide-3 kinase-Aktdependent pathways and support the relevance of these pathways in the observed estrogen-mediated reduction in myocardial injury. Key Words: estrogen Ⅲ estrogen receptors Ⅲ myocardial infarction Ⅲ cardiomyocyte Ⅲ apoptosis Ⅲ Akt Ⅲ PI3 kinase H eart failure is a growing public health problem, 1 with several studies demonstrating that women with heart failure have a better prognosis than men. 2,3,4,5,6,7 Whether endogenous sex hormones contribute to these differences in prognosis remains unknown. However, observational studies have demonstrated that postmenopausal women taking estrogen after a myocardial infarction (MI) have a lower incidence of heart failure. 8,9 Furthermore, retrospective analyses of multicenter heart failure trials have shown that postmenopausal women taking estrogen have a better prognosis than women not on estrogen, 10,11 supporting that estrogen may improve heart failure prognosis.Several studies have demonstrated increased cardiomyocyte apoptosis in failing hearts, 12,13 and further evidence suggests that apoptosis contributes to heart failure progression. 14,15 Moreover, autopsy studies have shown that female gender is associated with less cardiomyocyte apoptosis in normal and failing hearts compared with males. 16,17,18,19 These observed gender differences in cardiomyocyte survival provide a plausible explanation for the beneficial effect of female gender on heart failure progression.We recently showed that physiological estrogen replacement in ovariectomized female mice reduces infarct size both early and late after left c...

Background-We have shown previously that 17β-estradiol (E2) increases left ventricular (LV) and cardiomyocyte hypertrophy following myocardial infarction (MI). However, E2 decreases hypertrophy in pressure overload models. We hypothesized that the effect of estrogen on cardiac hypertrophy was dependent on the type of hypertrophic stimulus.

No abstract

Sudden cardiac death (SCD) is a significant cause of mortality in patients suffering from heart failure and left ventricular dysfunction. Implantable cardioverter defibrillators have been shown to effectively reduce the incidence of SCD in this population. Recent clinical trials have redefined the indications and patient profiles for their use: from secondary prevention to primary prevention of SCD. In this article, we review the clinical trials contributing to the current practice guidelines, which include device therapy.