[Pathogenesis of alcoholic liver injury (author's transl)].

The effects of ethanol on hepatic cellular metabolism and structure depend mainly on the dose and duration of intake. Following the ingestion of a substantial amount of ethanol, its presence alters a number of hepatic functions in part because of the change in the hepatic redox state (NADH/NAD ratio), resulting for instance in reduction of lipid oxidation. Furthermore, chronic ethanol consumption, at least in its early stages, produces adaptive metabolic changes in the endoplasmic reticulum which result not only in increased metabolism of drugs and accelerated lipoprotein production but also in activation of hepatotoxic compounds. Even more extended periods of ethanol intake result in damage to cell organelles in what can be considered a third stage of the alcohol effect namely that of injury. The injury involves primarily mitochondria, possibly as a consequence of effects of acetaldehyde, the first product of ethanol metabolism. Metabolites of ethanol also alter microtubular function. A defect in protein secretion may be the basis for protein retention and "ballooning" of the hepatocyte. Prolongation of ethanol induced injury eventually culminates in hepatic lesions such as alcoholic hepatitis and cirrhosis. Ethanol can be incriminated as a direct etiologic agent of the liver injury, since liver cirrhosis has been reproduced experimentally in baboons fed alcohol, despite an adequate diet.