Myo-inositol in depressive and healthy subjects determined by frontal 1H-magnetic resonance spectroscopy at 1.5 tesla.
Myo-inositol (mI) as a precursor in the phosphatidylinositol second messenger system has been reported to be reduced in depression. By means of proton-magnetic resonance spectroscopy (1H-MRS) the mI levels in the frontal brain were investigated in vivo in the present study. Twenty-two patients (mean age: 42.8 +/- 10.7 years) with depressive episodes according to ICD 10 (HAMD score > 17) were compared to 22 healthy subjects (28.0 +/- 5.3 years). Two voxels (30 x 20 x 20 mm3) in the frontal lobes were examined in a Siemens Magnetom SP 4000 at 1.5 T (STEAM sequence: TR = 3500 ms, TE = 55 ms). With the total creatine (Cr) as an internal standard, mI/Cr ratios were calculated to follow the mI levels. In the left frontal lobe, mI/Cr was 0.43 +/- 0.06 in depressive patients and 0.46 +/- 0.07 in healthy subjects; concerning the right frontal lobe, mI/Cr was 0.46 +/- 0.08 and 0.48 +/- 0.06, respectively. There were neither significant differences between the two groups nor between the hemispheres. Since there was a significant positive correlation (R = 0.6) between the age and the mI/Cr in the right frontal lobe of depressed patients, age matched pairs analysis was performed (n = 2 x 10, in each group: nine females, one male, < 40 years). In the right frontal lobe, the patients' mI/Cr of 0.40 +/- 0.05 was now significantly lower than the controls' mI/Cr of 0.45 +/- 0.06. However, most of the patients were on antidepressive medication. Interestingly, it was exactly this group of patients which showed significantly lower mI levels. We regard our investigation as a pilot study which suggests an influence of age and antidepressants on mI levels and should be taken into consideration in further investigations in depressive patients.
Frey
R
R
Department of General Psychiatry, University Hospital of Psychiatry, Vienna, Austria.
Metzler
D
D
Fischer
P
P
Heiden
A
A
Scharfetter
J
J
Moser
E
E
Kasper
S
S
D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D000928:Antidepressive Agents / Q000627:therapeutic use; D003401:Creatine / Q000378:metabolism; D003863:Depression / Q000175:diagnosis / Q000188:drug therapy / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism*; D006801:Humans; D007294:Inositol / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019906:Nuclear Magnetic Resonance, Biomolecular; D010865:Pilot Projects; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012737:Sex Factors; D018709:Statistics, Nonparametric
D000928:Antidepressive Agents; D007294:Inositol; D003401:Creatine