| BackgroundThe underlying neurobiology of alcoholism is not well understood. Clinical,neuropsychological and functional neuroimagine studies in alcoholism suggest impaired frontal lobe function.Despite these findings, morphological studies have failed to show consistent structural abnormalities in the frontal lobe.This may be because traditional techniques are not sensitive enough to detect structural abnormalities.In vivo proton magnetic resonance spectroscopy(~1H-MRS)is a safe and noninvasive tool that can provide information about neurotransmitter levels and neuronal integrity,in addition to measures of energy metabolism.N-acetylaspartate(NAA)is the second most abundant amino acid in the central nervous system and is reliably measured by ~1H-MRS.ObjectiveProton magnetic resonance spectroscopy may elucidate the molecular underpinnings of alcoholism-associated brain metabolites changes and the progression of alcohol-related disorders. MethodsUsing proton magnetic resonance spectroscopy,we determined absolute concentrations of N-acetylaspartate(NAA),creatine(Cr),and Choline(Cho)in the frontal lobe white and grey matter in 10 alcoholisms and 10 normal controls.All patients were examined within 3 to 7 days of their last drink.Patients who did not relapse were again studied after 1 months of abstinence.10 normal controls undergo only ~1H-MRS and WCST once.Using Funtool2 Soft,which is provided by GE Medical Inc, to determine ratios of areas under the metabolite peeks of the proton spectra[i.e.,NAA/Cr,Cho/Cr].All the data were analyzed by Stata 9.0 and criterion of significance was set at p＜0.05.Results1.The NAA/Cr ratio at baseline was significantly lower in patient than in controls(left white matter:1.45±0.38 vs 2.16±0.40;left grey matter:1.17±0.11 vs 1.67±0.33;right white matter:1.59±0.25 vs 2.09±0.41;right grey matter:1.44±0.40 vs 1.56±0.30;all p＜0.05).2.There were also significantly differences in NAA/Cr ratio between alcoholics underwent short-term sobriety(1-7days)and continuing abstinence(30 days).3.No significant group difference in Cho/Cr were noted in the left or the right frontal region in either alcoholics or the health subjects(all p＞0.05);4.There was no significantly lateralized asymmetry for NAA/Cr in either alcoholics or the health subjects(all p＞0.05);5.After abstinence,the changes of NAA/Cr ratio in right grey matter were significantly correlated to the neuropsychological improvement.ConclusionSobriety has marked and early,globally averaged and regionally specific metabolic changes as well as functional benefits for convalescent alcoholisms.1.The reduced NAA/Cr ratios in alcoholics suggest neuronal dysfunction and/or decreased neuronal density in the frontal region.2.The decreased NAA/Cr ratios in alcoholics which will be increased after abstinence suggest the alcoholism-associated brain damage be partially recovered.3.After abstinence,the changes of NAA/Cr ratio in right grey matter were significantly correlated to the neuropsychological improvement.4.Further studies are needed to determine whether the reduce NAA/Cr ratios is a risk factor for,or consequence of,malignant,early-onset alcoholism.5.The influence of withdrawal,age,gender,medication and cigarette needs to be explorer further in longitudinal studies.
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