Formic Acid, a Novel Metabolite of Chronic Ethanol Abuse, Causes Neurotoxicity, Which Is Prevented by Folic Acid Alcoholism: Clinical and Experimental Research 31 (12), 2114–2120.
Methanol is endogenously formed in the brain and is present as a congener in most alcoholic beverages. Because ethanol is preferentially metabolized over methanol (MeOH) by alcohol dehydrogenase, it is not surprising that MeOH accumulates in the alcohol-abusing population. This suggests that the alcohol-drinking population will have higher levels of MeOH’s neurotoxic metabolite, formic acid (FA). FA elimination is mediated by folic acid. Neurotoxicity is a common result of chronic alcoholism.
This study shows for the first time that FA, found in chronic alcoholics, is neurotoxic and this toxicity can be mitigated by folic acid administration.
To determine if FA levels are higher in the alcohol-drinking population and to assess its neurotoxicity in organotypic hippocampal rat brain slice cultures.
Serum FA levels in the alcoholics (mean ± SE: 0.416 ± 0.093 mmol/l, n = 23) were significantly higher than in controls (mean ± SE: 0.154 ± 0.009 mmol/l, n = 82) (p <>n = 20), whereas it was >0.15 mmol/l in CSF of 3 of the 4 alcoholic cases. Low doses of FA from 1 to 5 mmol/l added for 24, 48 or 72 hours to the rat brain slice cultures caused neuronal death as measured by propidium iodide staining. When folic acid (1 μmol/l) was added with the FA, neuronal death was prevented.
Formic acid may be a significant factor in the neurotoxicity of ethanol abuse. This neurotoxicity can be mitigated by folic acid administration at a clinically relevant dose.
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