Red blood cells: A new major modality for acetaldehyde transport from liver to other tissues

Abstract

After alcohol ingestion, an amount of acetaldehyde much larger than previously appreciated by measurements in plasma is released from the splanchnic areas, travels reversibly bound to the red blood cells, and is taken up by extrahepatic tissues. The magnitude of this new modality for acetaldehyde transport is markedly enhanced in alcoholics and may contribute to acetaldehyde toxicity in extrahepatic tissues. Acetaldehyde, a very reactive metabolite of ethanol, has a number of effects that have been incriminated in several manifestations of alcoholism such as formation of false neurotransmitters (1,2), stimulation of collagen synthesis (3), inhibition of tubulin polymerization (4), mutagenicity (5,6), and inhibition of cardiac protein synthesis (7). However, after alcohol intake, minimal or undetectable concentrations of this metabolite have been consistently found in plasma or in human blood when hemolysis is prevented to avoid in vitro (artefactual) formation of acetaldehyde from ethanol by red cell components (8). The measurement of acetaldehyde in red blood cells or in total blood has been hampered by variable sensitivity, poor recovery and/or very high in vitro artefactual formation from ethanol, which has resulted in widely differing values. The development of a method that allowed for acetaldehyde measurement in the red blood cells with good recovery and small artefactual formation (9) prompted us to investigate the possibility that acetaldehyde could be transported in the blood reversibly bound to the red blood cells.