Cardioprotective Effects of 17β-Estradiol Produced by Activation of Mitochondrial ATP-Sensitive K+Channels in Canine Hearts

Differential Role of K ATP Channels Activated by Conjugated Estrogens in the Regulation of Myocardial and Coronary Protective Effects

“…The ischemia-limiting effect of estrogen observed in the present study confirms our previous studies performed in animals 7,8 and patients. 9 IP is a graded phenomenon in which endogenous mediators might play a distinct and/or additive role depending on the duration and timing of the preconditioning regimen used.…”

“…Thus, more clinical studies are needed to confirm the beneficial effects of acute administration of estrogen in females, although we have demonstrated in canine hearts that estrogen limits myocardial infarction size resulting from coronary artery occlusion and reperfusion regardless of sex. 7 Blumenthal et al 30 demonstrated an improvement in coronary vasodilation in males with intravenous conjugated estrogen. However, Collins et al 31 have shown a lack of effect in male coronary arteries in response to acute loading of estrogen for low availability or activity of estrogen receptors in male tissues.…”

“…4 A specific antagonist of the ET A receptor (BQ123) has been shown to attenuate coronary vasoconstriction in experimental and clinical studies. 5,6 We have demonstrated that estrogen is cardioprotective against infarct of any size and myocardial ischemia by activation of ATP-sensitive potassium (K ATP ) channels in animals 7,8 and in humans, 9 similar to ischemic preconditioning (IP). Cardioprotection via K ATP channels may be an integral player in IP, in which brief periods of ischemia and reperfusion before a sustained ischemic stress protect the heart.…”

Age- and Gender-Related Differences in Ischemia/Reperfusion Injury and Cardioprotection: Effects of Diazoxide

“…Our data would suggest that estradiol levels may play an important role in cardioprotection. Support for this hypothesis comes from studies demonstrating that supplemental 17β-estradiol, the active form of estradiol, enhances cardioprotection [20,21]. Hale and coworkers [20] have previously demonstrated that supplemental 17β-estradiol significantly decreased necrosis in rabbits after ischemia and reperfusion.…”

Greater antiarrhythmic activity of acute 17β‐estradiol in female than male anaesthetized rats: correlation with Ca2+ channel blockade

“…Previously, it has been shown that a single intravenous dose of 100 mg of conjugated equine estrogens (McHugh et al, 1995) or intracoronary infusion of 17b-estradiol (Node et al, 1997) reduced ischaemia-induced arrhythmias in anaesthetized dogs. Another study in anaesthetized dogs suggested that a bolus dose of 10 mg kg À1 of 17b-estradiol resulted in a trend of more animals surviving ischaemia and reperfusion, but it is difficult to interpret the effects on arrhythmias in this study as animals with intractable VF were excluded from the analysis (Lee et al, 2000). Other work has focused on the effects of estrogens on reperfusion-induced arrhythmias rather than those observed during ischaemia (Node et al, 1997;McHugh et al, 1998;Tsai et al, 2002).…”