Chronic alcohol intake-induced oxidative stress and apoptosis: role of CYP2E1 and calpain-1 in alcoholic cardiomyopathy

Cytochrome P-450 2E1 CYP2E1 induction has been linked to oxidative stress in a number of experimental models. The aim of this study was to investigate the relationship between CYP2E1 activity and markers of oxidative stress and cardiac cell apoptosis during the development of alcoholic cardiomyopathy (ACM). Changes in left ventricular morphology were evaluated in 4 groups of chronically instrumented dogs (control; alcohol-receiving; and alcohol-receiving plus treatment with either valsartan or carnitine) after 6 months of treatment. CYP2E1 and calpain-1 protein expression were determined by Western blotting, and apoptosis evaluated by TUNEL and immunohistochemistry. Malonyl dialdehyde levels were assessed as a marker of oxidative stress, while superoxide dismutase and glutathione peroxidase levels were evaluated as markers of antioxidant defense mechanisms. Expression of CYP2E1 was increased in the alcohol-receiving group compared with controls (P<0.05) and was associated with oxidative stress. Similarly, expression of Bad and calpain-1 protein was increased after chronic alcohol exposure, while Bcl-xL protein expression remained at a low level. Bad and calpain-1 protein expressions were significantly inhibited by treatment with valsartan or carnitine, while expression of Bcl-xL protein was increased (P<0.05). Collectively, our results indicate a possibly significant role for CYP2E1 in the oxidative stress associated with chronic alcoholism. The resulting increase in oxidative stress is accompanied by cellular apoptosis and may ultimately contribute to tissue remodeling and ACM. Importantly, these alcohol-induced effects may be abrogated by means such as angiotensin 1 receptor blockade or carnitine supplementation.