Effect of Alcohol Administration on Mg2+ Homeostasis in H9C2 Cells.

Alcoholic cardiomyopathy represents one of the main clinical complications in chronic alcoholics. This pathology contrasts the seemingly beneficial effect of small doses of alcohol on the cardiovascular system. Studies carried out in liver cells exposed acutely or chronically to varying doses of EtOH indicate that intrahepatic alcohol metabolism results in a major loss of cellular Mg²⁺. To investigate whether EtOH administration also induced Mg²⁺ extrusion in cardiac cells, H9C2 cells were exposed to varying doses of EtOH for short- or ling-term periods of time. The results indicate that H9C2 cells exposed to EtOH doses higher than 0.1% (v/v, or 15 mM) extruded Mg²⁺ into the extracellular medium on a time- and dose-dependent manner. Consistent with the involvement of cyP4502E1 in metabolizing EtOH, administration of chloro-methiazole (CMZ) as an inhibitor of the cytochrome prevented EtOH-induced Mg²⁺ loss to a large extent. EtOH-induced Mg²⁺ extrusion was also prevented by the administration of di-thio-treitol (DTT) and n-acetyl-cysteine (NAC), two agents that prevent the negative effects of ROS formation and free radicals generation associated with EtOH metabolism by cyP4502E1. Taken together, our data indicate that Mg²⁺ extrusion also occur in cardiac cells exposed to EtOH as a result of alcohol metabolism by cyP4502E1 and associated free radical formation. Interestingly, Mg²⁺ extrusion only occurs at doses of EtOH higher than 0.1% administered for an extended period of time. The significance of Mg²⁺ extrusion for the onset of alcoholic cardiomyopathy remains to be elucidated.