Antioxidant Protects Heart from Oxidative Stress

By CP Staff

A recently published study investigated the activity of a potent antioxidant in experimentally induced alcoholism. Excessive alcohol intake results in several pathological conditions due to increased oxidative free radical damage, such as alcoholic heart disease.

In this new study, researchers investigated the effect of N-acetyl cysteine (NAC) on experimentally induced alcoholism. Two groups of mice were fed either a standard diet or a diet supplemented with alcohol for 30 days. After that time, the mice that had ingested alcohol were divided into four groups: (1) mice with 30 percent alcohol intake; (2) mice with 30 percent alcohol intake plus NAC; (3) mice switched from alcohol to water; and (4) mice switched from alcohol to water plus NAC.

The results showed that the mice receiving the 30 percent alcohol-intake diet had several pathological changes. These mice exhibited decreased feed efficiency with increased energy expenditure at rest and maximal oxygen intake, resulting in lower body weight and pathological changes in the heart tissue (myocardium). The mice on the alcohol-supplemented diet also had an increase in the ratio of the weight of the heart to total body weight, indicating hypertrophy of the heart muscle.

Myocardial lipid hydroperoxides were also increased indicating increased oxidative stress in the heart tissue. Additionally, levels of the antioxidant enzyme superoxide dismutase were increased and levels of the enzyme glutathione peroxidase were decreased, which is also indicative of increased oxidative damage. Furthermore, levels of several other metabolic markers indicated increased fatty acid degradation over anaerobic metabolism, meaning the heart muscle cells were “burning” fats instead of aerobic carbohydrate metabolism to create cellular energy (ATP). This metabolic shift increases the risk of lipid toxicity in the heart cells.

The rats switched from alcohol to water had normal resting metabolic rate to body weight ratios, as well as normal markers of oxidative stress in the heart. The mice that received NAC in addition to alcohol or water had lower resting metabolic rate to body weight ratios. The mice receiving NAC also had increased levels of cardiac glutathione peroxidase, as well as normal markers of anaerobic metabolism, indicating lower oxidative stress and higher carbohydrate oxidation for cellular energy.

The study authors concluded, “NAC prevented ethanol-induced calorimetric changes and reduced myocardial oxidative stress-enhanced carbohydrate oxidation, thus optimizing myocardial energy metabolism in both alcoholic and abstinence condition.”

Reference:

Seiva FR, Amauchi JF, Rocha KK, Ebaid GX, Souza G, Fernandes AA, Cataneo AC, Novelli EL. Alcoholism and alcohol abstinence: N-acetylcysteine to improve energy expenditure, myocardial oxidative stress, and energy metabolism in alcoholic heart disease. Alcohol. 2009 Dec;43(8):649-56.