Acetaldehyde and its condensation products as markers in alcoholism

Several studies show that recently abstaining alcoholics generate higher circulating levels of acetaldehyde than nonalcoholics following ethanol administration. It is conceivable that levels of stable adducts (tetrahydroisoquinolines and tetrahydro-beta-carbolines) derived from acetaldehyde condensations with biogenic amines also might be increased in alcoholics consuming ethanol, thus serving in body fluids as chemical markers that are more persistent than acetaldehyde itself. Limited human and rat studies indicate that urinary excretion of an oxidized tryptamine condensation product (harmane) and of an acetaldehyde/serotonin condensation product is elevated by chronic ethanol. Salsolinol, the derivative of acetaldehyde and dopamine, does not appear to be a meaningful urinary marker, but levels of the related pyruvic acid/dopamine product may be increased by ethanol. Blood assays of condensation products have been limited in number and equivocal. Condensation product measurements are complicated not only by artifacts (formation during analyses), but by other inherent problems. Products of interest often are constituents of diets and alcoholic beverages. For this and perhaps endogenous metabolic reasons, traces of condensation products are normally excreted by nondrinking individuals. Furthermore, the assays require high sensitivity and specificity and are not easily adapted to routine use. Thus, although several condensation products have initial appeal as clinical or pathological indicators in chronic alcoholism, thorough and statistically sound studies are needed before conclusions can be reached concerning any particular biogenic amine-derived product.