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

Background: Acetaldehyde-derived protein condensates (adducts) have been su ggested as promising biological markers of alcohol abuse because they repre sent actual metabolites of ethanol. However, the detection of such condensa tes in vivo has been hampered by a lack of sensitive and specific methods. Methods: To develop new approaches for the detection of acetaldehyde adduct s, we have raised antibodies against condensates with acetaldehyde and lipo proteins, which have previously been shown to be readily modified by acetal dehyde 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, ox idation, and acetylation. Results: The antibodies raised against low-density lipoprotein (LDL)/acetal dehyde, very low density lipoprotein (VLDL)/acetaldehyde, and bovine serum albumin/acetaldehyde all reacted with protein adducts generated at physiolo gically relevant concentrations of acetaldehyde in vitro, whereas the antib odies raised against malondialdehyde/LDL, oxidized LDL, or acetylated LDL w ere not found to cross-react with the acetaldehyde-derived adducts. In assa ys for acetaldehyde adducts from erythrocyte and serum proteins of patients with excessive ethanol consumption (n = 32) and healthy control individual s (n = 22), the antibody prepared against the acetaldehyde/VLDL condensate was found to provide the most effective detection of acetaldehyde adducts i n vivo. Conclusions: Current data indicate that acetaldehyde generates immunogenic adducts with lipoproteins in vivo. Antibodies raised against the VLDL/aceta ldehyde may provide a basis for new diagnostic assays to examine excessive alcohol consumption.