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(Circulation. 2007;115:3197-3204.)
© 2007 American Heart Association, Inc.
Molecular Cardiology |
From the Vascular Medicine Research Unit (M.S., H.O., K.T., C.-Y.W., J.K.L.), Brigham and Womens Hospital and Harvard Medical School, Cambridge, Mass; Cardiovascular Research, Institute of Physiology (C.M.M.), University of Zurich, and Cardiology, Cardiovascular Center (C.M.M.), University Hospital Zurich, Zurich, Switzerland; and Molecular Cardiovascular Research (G.W.D.), University of Cincinnati, Cincinnati, Ohio.
Correspondence to James K. Liao, MD, Brigham and Womens Hospital, 65 Landsdowne St, Room 275, Cambridge, MA 02139. E-mail jliao{at}rics.bwh.harvard.edu
Received August 14, 2006; accepted April 20, 2007.
Background Epidemiological studies have shown gender differences in the incidence of congestive heart failure (CHF); however, the role of estrogen in CHF is not known. We hypothesize that estrogen prevents cardiomyocyte apoptosis and the development of CHF.
Methods and Results 17ß-Estradiol (E2, 0.5 mg/60-day release) or placebo pellet was implanted subcutaneously into male G
q transgenic (Gq) mice. After 8 weeks, E2 treatment decreased the extent of cardiac hypertrophy and dilation and improved contractility in Gq mice. E2 treatment also attenuated nicotinamide adenine dinucleotide phosphate oxidase activity and superoxide anion production via downregulation of Rac1. This correlated with reduced apoptosis in cardiomyocytes of Gq mice. The antioxidative properties of E2 were also associated with increased expression of thioredoxin (Trx), Trx reductases, and Trx reductase activity in the hearts of Gq mice. Furthermore, the activation of apoptosis signal-regulating kinase 1 and its downstream effectors, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase, in the hearts of Gq mice was reduced by long-term E2 treatment. Indeed, E2 (10 nmol/L)-treated cardiomyocytes were much more resistant to angiotensin IIinduced apoptosis. These antiapoptotic and cardioprotective effects of E2 were blocked by an estrogen receptor antagonist (ICI 182,780) and by a Trx reductase inhibitor (azelaic acid).
Conclusions These findings indicate that long-term E2 treatment improves CHF by antioxidative mechanisms that involve the upregulation of Trx and inhibition of Rac1-mediated attenuated nicotinamide adenine dinucleotide phosphate oxidase activity and apoptosis signal-regulating kinase 1 /c-Jun N-terminal kinase/p38 mitogen-activated protein kinasemediated apoptosis. These results suggest that estrogen may be a useful adjunctive therapy for patients with CHF.
Key Words: apoptosis antioxidants heart failure hormones
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