Muscle antioxidant status in chronic alcoholism

BACKGROUND Chronic myopathy due to excessive ethanol intake is one of the most frequent causes of acquired skeletal myopathy in developed countries. Its pathogenesis is multi-factorial, only partially clarified, and antioxidant imbalance has been suggested to influence its development, being a type II glucolytic, fast-twitch fiber subset more sensitive to this effect.

We assessed superoxide dismutase, glutathione peroxidase, and glutathione reductase enzyme activities as well as the total antioxidant status capacity in muscle samples obtained from 41 chronic alcoholic males and 12 age-matched controls. Alcoholic skeletal myopathy was defined according to standard histologic criteria. We evaluated the influence of ethanol consumption, caloric and protein nutritional status, and the presence of skeletal myopathy with the tissue activities of these antioxidant enzymes.

Chronic alcoholics showed a 16% reduction in glutathione peroxidase and a 13% increase of superoxide dismutase in the skeletal muscle, compared with controls (p < 0.05, both). Muscle antioxidant changes in chronic alcoholics were not related to the presence of skeletal myopathy, parameters of alcohol consumption, or conventional nutritional parameters.

Antioxidant muscle enzyme activities are partially disturbed in chronic alcoholism, although not related to the presence of myopathy, amount of ethanol consumed, or the nutritional status of the patients. Further studies should assess other aspects not included in the present study such as muscle site-specific changes in antioxidant status/oxidative damage, specific fiber-type sensitivity to alcohol, and type and quantity of antioxidant content of the diet or in the alcohol beverages.