Assays for acetaldehyde-derived adducts in blood proteins based on antibodies against acetaldehyde/lipoprotein condensates.

Background: Acetaldehyde-derived protein condensates (adducts) have been suggested as promising biological markers of alcohol abuse because they represent actual metabolites of ethanol. However, the detection of such condensates in vivo has been hampered by a lack of sensitive and specific methods.
Methods: To develop new approaches for the detection of acetaldehyde adducts, we have raised antibodies against condensates with acetaldehyde and lipoproteins, which have previously been shown to be readily modified by acetaldehyde in vitro. The characteristics of these antibodies were compared with those raised against bovine serum albumin/acetaldehyde adduct and against other types of lipoprotein modifications, as induced by malondialdehyde, oxidation, and acetylation.
Results: The antibodies raised against low-density lipoprotein (LDL)/acetaldehyde, very low density lipoprotein (VLDL)/acetaldehyde, and bovine serum albumin/acetaldehyde all reacted with protein adducts generated at physiologically relevant concentrations of acetaldehyde in vitro, whereas the antibodies raised against malondialdehyde/LDL, oxidized LDL, or acetylated LDL were not found to cross-react with the acetaldehyde-derived adducts. In assays for acetaldehyde adducts from erythrocyte and serum proteins of patients with excessive ethanol consumption (n = 32) and healthy control individuals (n = 22), the antibody prepared against the acetaldehyde/VLDL condensate was found to provide the most effective detection of acetaldehyde adducts in vivo.
Conclusions: Current data indicate that acetaldehyde generates immunogenic adducts with lipoproteins in vivo. Antibodies raised against the VLDL/acetaldehyde may provide a basis for new diagnostic assays to examine excessive alcohol consumption.