Relationship between N-acetyl-aspartate in gray and white matter of abstinent methamphetamine abusers and their history of drug abuse: a proton magnetic resonance spectroscopy study.
OBJECTIVE
Altered concentrations of the brain metabolites, including N-acetyl-aspartate (NAA) and myo-inositol (MI), may indicate neurotoxicity associated with drug abuse. In this study, the authors explored differences in brain metabolites between abstinent methamphetamine (MA) abusers and healthy comparison subjects and the associations between metabolite concentrations and clinical characteristics.


METHODS
Proton magnetic resonance spectroscopy (MRS) was performed on 30 abstinent MA abusers and 20 healthy comparison subjects. Two sets of MA user subgroups were defined depending on abstinence duration (greater or less than 6 months) or the total cumulative MA dose (greater or less than 100 g lifetime). NAA and other metabolites were measured in the frontal gray and white matter and compared between MA abuser groups and healthy comparison subjects.


RESULTS
MI concentrations were higher for the MA abusers relative to healthy comparison subjects. NAA concentration was lower in frontal white matter of MA abusers with a 'large' cumulative dose relative to those with a 'small' cumulative dose and to healthy comparison subjects. Additionally, in MA abusers NAA concentrations in frontal white matter correlated inversely with the cumulative MA dose. In contrast, there was no significant difference in frontal gray matter NAA concentration among the three groups. However, frontal gray matter NAA concentrations for MA abusers correlated negatively with the total cumulative MA dose and positively with the duration of abstinence. There were no differences between the different MA user groups for MI.


CONCLUSIONS
The current findings suggest that MA-induced metabolic alterations of frontal gray and white matter are dose-dependent, for primarily male subjects. Additionally, these findings potentially suggest that the MA-related abnormalities may, in part, recover with abstinence in gray matter, but not in the white matter regions.
Sung
Young Hoon
YH
Department of Psychiatry, Seoul National University College of Medicine and Hospital, Seoul 110-744, Republic of Korea.
Cho
Soo Churl
SC
Hwang
Jaeuk
J
Kim
Seog Ju
SJ
Kim
Hyungjun
H
Bae
Sujin
S
Kim
Namguk
N
Chang
Kee Hyun
KH
Daniels
Melissa
M
Renshaw
Perry F
PF
Lyoo
In Kyoon
IK
D000328:Adult; D019969:Amphetamine-Related Disorders / Q000378:metabolism* / Q000473:pathology*; D000704:Analysis of Variance; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D001479:Basal Ganglia / Q000473:pathology; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D005625:Frontal Lobe / Q000473:pathology; D006801:Humans; D007294:Inositol / Q000032:analysis; D007723:Korea; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008694:Methamphetamine / Q000009:adverse effects*; D008875:Middle Aged; D009498:Neurotoxins / Q000378:metabolism; D011522:Protons; D013997:Time Factors
D009498:Neurotoxins; D011522:Protons; D001224:Aspartic Acid; D008694:Methamphetamine; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline