Elevated myo-inositol in gray matter of recently detoxified but not long-term abstinent alcoholics: A preliminary MR spectroscopy study

Background: Individuals in short-term abstinence from chronic alcohol consumption commonly have neuropsychological impairments with parallel abnormalities in brain structure. Stable, long-term sobriety often results in improvements in both brain structure and function, although the mechanisms underlying these changes are currently not well understood. Methods: To investigate further the neurobiological underpinnings of alcohol-associated brain abnormalities in short-term and long-term abstinence from alcohol, proton magnetic resonance spectroscopy (echo time, 35 msec; repetition time, 1.5 sec) was used to assay metabolites in the anterior centrum semiovale, anterior cingulate gyrus, and right thalamus of two groups of non-Korsakoff alcoholic men, at different stages of abstinence, compared with a control group of alcohol-nonabusing men. Absolute concentrations of N-acetylaspartate, choline, myo-inositol, and creatine were measured in four recently detoxified alcoholics (mean age, 48.7 years; median abstinence, 41.5 days), five long-term abstinent alcoholics (mean age, 45.1 years; median abstinence, 1.7 years), and five nonalcoholic controls (mean age, 45.0 years). Results: Although there were no between-group differences in concentrations of N-acetylaspartate, choline, or creatine, recently detoxified alcoholics had significantly higher myo-inositol in the thalamus, compared with controls and long-term abstinent alcoholics, and significantly higher myo-inositol in the anterior cingulate gyrus, compared with the controls. Conclusions: Elevations in myo-inositol in recently detoxified alcoholics are compatible with an acute alcohol cytotoxicity model. myo-Inositol is elevated in hyperosmolar states such as hypernatremia, renal failure, and diabetes; alcohol-induced hyperosmolarity may trigger accumulation of myo-inositol to stabilize the intracellular environment. Increases in myo-inositol may also reflect proliferation or activation of glia. The reduction of myo-inositol to control group levels in long-term abstinent alcoholics may reflect osmolar stability in abstinent alcoholics and/or a reduction in glial cell activation.