Otpcjpmdroa and Protection by Ethanol and Polyphenols

University Of Alabama At Birmingham, Birmingham AL

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Abstract

Thrombosis leads to the occlusion of the coronary vasculature and the resulting ischemic episode can only be alleviated by inducing reperfusion of the ischemic myocardium. Molecular mechanisms that lead to protection of the myocardium from ischemia-reperfusion injury are unclear and the impact of dietary components such as polyphenolics and alcohol are barely understood. This project focuses on the beneficial effects of ethanol or the polyphenols found in red wine on mitochondrial function and apoptosis in the cardiomyocyte under stress from ischemia-reperfusion. Previous studies and preliminary data have shown that a major component of myocardial-reperfusion damage is due to mitochondrial dysfunction on reperfusion. It is hypothesized that chronic exposure to either ethanol or red wine polyphenols limits mitochondrial damage through nitric oxide-dependent mechanisms. Preliminary data supports these concepts and demonstrates a protective effect of oral, low dose treatment with ethanol in the ischemic-reperfused mouse heart. Given the finding that long-term exposure is required to reveal these effects and the concentration of ethanol or polyphenols in the heart during exposure is minimal it is postulated that transcriptional regulation is central to the mechanisms of cardioprotection. These data have led to the hypothesis that a critical mechanism contributing to low dose alcohol and polyphenol-dependent cardioprotection is through protection of mitochondria against ischemia-reperfnsion. This hypothesis will be tested by pursuit of the following Specific Aims: 1) Determine the effects of oral exposure of EtOH or PPs on mechanisms leading to increased NO bioavailability and modification of mt DNA and the mitochondrial proteome. 2) Determine changes in NO- dependent control of respiratory function in mitochondria isolated from the hearts of normal mice and animals given oral PPs or low dose EtOH and in response to ischemia-reperfusion. 3) Characterize the mechanisms leading to changes in protein modification and susceptibility to apoptosis in myocytes and mitochondria isolated from mice treated with low dose EtOH and PPs. The information gained from the accomplishment of these specific aims will give insight into the mechanisms of alcohol and polyphenol-dependent cardioprotection at the level of the mitochondrion.