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Effects of hormone therapy and dietary soy on myocardial ischemia/reperfusion injury in ovariectomized atherosclerotic monkeys

2008; Lippincott Williams & Wilkins; Volume: 15; Issue: 2 Linguagem: Inglês

10.1097/gme.0b013e31812e6b4a

1530-0374

Irma Herawati Suparto, J. Koudy Williams, Jamie L. Fox, Jawwad Yusuf, Dondin Sajuthi,

Cancer Risks and Factors

In Brief Objective: Hormone therapy (HT) and dietary soy (Soy) inhibit myocardial ischemia/reperfusion (I/R) injury in nonatherosclerotic animals. The aim of this study was to determine their independent and interactive effects on I/R in monkeys previously fed an atherogenic diet for 15 months. Design: Ovariectomized atherosclerotic monkeys (n = 40) were divided into one of four dietary treatment groups: (1) casein as the protein source, (2) casein and added HT (the equivalent of 5 μg ethinyl estradiol + 1 mg norethindrone acetate daily), (3) Soy protein providing 141 mg total isoflavones daily, or (4) Soy + HT. After 12 months monkeys were anesthetized, and their left anterior descending coronary artery was occluded for 1 hour and reperfused for 4 hours. Infarct size was the percentage of the area at risk not staining with triphenyltetrazolium chloride. Additional measures were myocardial blood flow, stroke volume, coronary output, myeloperoxidase, and malondialdehyde. Results: There was an interactive negative effect of HT + Soy to increase infarct size from approximately 30% (in other groups) to 55% (P = 0.0004). Additionally, there were negative main effects of Soy on blood flow, coronary output, and stroke volume during I/R (all P values <0.05). There were no effects of treatment on either myeloperoxidase or malondialdehyde. Conclusions: Neither HT nor Soy had beneficial effects, whereas their combination had harmful effects, on myocardial I/R injury in monkeys with preexisting atherosclerosis. The mechanism of this negative interaction remains unclear but may relate to Soy's negative effects on hemodynamics. Atherosclerotic ovariectomized monkeys were treated with dietary soy protein with or without traditional hormone therapy. Results indicate that soy protein, especially when combined with hormone therapy, increased the extent of postinfarction myocardial damage.