Psy-World

Changes in glial cells in major depression following antidepressant treatment can be detected by proton magnetic resonance spectroscopy.

Neurobiological abnormalities in the dorsolateral prefrontal cortex (DLPFC) have been shown by neuroimaging studies to be involved in the pathophysiology of major depressive disorder (MDD). Proton (1H) magnetic resonance spectroscopy (MRS) is a non-invasive neuroimaging tool that allows for the direct, in vivo and non-radioactive measurement of the metabolites in some brain regions. 1H-MRS studies of DLPFC in patients with MDD have given inconsistent results. The first aim of a recent study was to determine the metabolites of DLPFC in patients with MDD. The second aim was to determine the metabolite changes following antidepressant treatment. Seventeen drug-naïve female patients with a diagnosis of first-episode MDD and 13 healthy females were involved in the study. Single-voxel 1H-MRS imaging was carried out with a 3.0-T scanner and the voxel was placed in the left DLPFC. Psychopathology and MR were performed at the baseline for all subjects, and depressed subjects were reassessed following 8 weeks of antidepressant treatment. After data acquisition, an automated program was used for determination of the levels of N-acetyl aspartate (NAA), creatine (Cr), Choline (Cho), myoinositol (Ino), and NAA/Cr, Cho/Cr, Ino/Cr ratios were calculated. None of the metabolite ratios (NAA/Cr, Cho/Cr, and Ino/Cr) differed between patients and control subjects. After the treatment, Ino/Cr ratios increased compared to pretreatment values (0.67 ± 0.13 vs 0.58 ± 0.22, p = 0.032). There was no significant difference, however, between pre- and post-treatment NAA/Cr and Cho/Cr ratios. Since Ino is mainly stored in glial cells, it is considered as a marker of glial cells. Despite the lack of differences at baseline, increases in the Ino/Cr ratios after treatment might indicate the influence of antidepressants on damage in the glial cells. The fact that Ino/Cr ratios are increased following treatment in the absence of any change in NAA and Cho could indicate the role of glial cells in MDD. Kaymak SU, Demir B, Oğuz KK, Şentürk S, Uluğ B (2009). Antidepressant effect detected on proton magnetic resonance spectroscopy in drug-naïve female patients with first-episode major depression. Psychiatr Clin Neurosci 63:350-356. Updated June 2009