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Valproate‐induced metabolic changes in patients with epilepsy: Assessment with 1 H‐MRS
Author(s) -
Garcia Meritxell,
Huppertz HansJuergen,
Ziyeh Sargon,
Buechert Martin,
Schumacher Martin,
Mader Irina
Publication year - 2009
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1167.2008.01801.x
Subject(s) - glutamine , creatine , hyperammonemia , medicine , glutamate receptor , parietal lobe , choline , endocrinology , epilepsy , occipital lobe , phosphocreatine , chemistry , biochemistry , energy metabolism , amino acid , receptor , psychiatry , radiology
Summary Purpose: Valproate (VPA) interferes with mitochondrial metabolism causing hyperammonemia, thereby shifting the balance reaction of glutamine (Gln)/glutamate (Glu) toward Gln. In this study we wanted to determine whether metabolic changes could be reproduced in VPA‐treated patients with epilepsy and whether the results differed from those known in chronic hepatic encephalopathy (CHE). Methods: Seven patients with epilepsy pretreated with VPA and seven healthy volunteers were investigated on a 3T‐scanner. We performed proton magnetic resonance spectroscopy ( 1 H‐MRS) using a short echo time point‐resolved spectroscopy (PRESS) in the parietal and occipital lobe, respectively. Spectral analysis was performed by LCModel, allowing a separation of Glu and Gln at 3T. Absolute values of myo ‐Inositol (mI), choline (Cho), creatine (Cr), N ‐acetyl‐aspartate (NAA), glutamine (Gln), glutamate (Glu), and the sum of Gln and Glu (Glx) were calculated. Results: In the parietal lobe, mI was significantly decreased in the patients’ group compared to the healthy volunteers. After separation of the signals of Gln and Glu, a significant increase of Gln was observed in the parietal lobe in the patients’ group. No significant differences in the occipital spectra could be observed between the groups. Discussion: In VPA‐treated patients the alteration of the Glu/Gln ratio differs from that in patients with CHE, where Glx is markedly increased because of an increase in Gln. The expected shift from the biochemical balance reaction of Gln/Glu induced by VPA could be reproduced for the parietal lobe. Significantly reduced mI in the parietal lobe of VPA‐treated patients most likely reflects an osmolytic compensation for high Gln.