13C-MRS MEASUREMENT OF CEREBRAL GLUTAMATE METABOLISM IN EPILEPSY PATIENTS BY ORAL ADMINISTRATION OF 13C-GLUCOSE
Abstract number :
3.171
Submission category :
Year :
2002
Submission ID :
436
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Taisuke Otsuki, Tomoyuki Kanamatsu, Yasuzo Tsukada, Kazuya Okamoto, Hidehiro Watanabe. Neurosurgery, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan; Institute of Life Science, Soka University, Hachioji, Tokyo, Japan; Medical Systems R&
RATIONALE: We report a study on cerebral glutamate metabolism by oral administration of 13C-glucose in intractable occipital lobe epilepsy patients (n=5) comparing to young healthy control (n=8).
METHODS: The written consent was obtained after being informed about the procedure. A 13C-MRS system based on a 2T TOSHIBA 13C-MRS research system was used.13C spectra were simultaneously obtained from two voxels on bilateral occipital lobes after oral administration of 99% enriched [1-13C] glucose (Glc-1; 0.75g per 1kg body weight) in a 30% weight /volume water solution. Each voxel size is 48 ml or 64 ml and an acquisition time is 5 min. 13C-MRS spectra were acquired for 2-3.5 hours to obtain time courses for 13C-incorporated glutamate and glutamine. Blood samples were taken from the antecubital vein and analyzed to measure the blood sugar level, the insulin level, and 13C fractional enrichment (F.E.) of Glc-1. Rate of TCA cycle (Vtca) and glutamate-glutamine cycle (Vgln) of each individual was computed based on the previously proposed mathematical model (Mason et al.,1992).
RESULTS: A mean value of Vtca was slightly decreased in epilepsy patients [control: 0.372 umol/g/min (SD 0.191), epilepsy: 0.276 umol/g/min (SD 0.115) ], whereas Vgln was significantly increased in epilepsy patients [control: 0.027 umol/g/min (SD 0.010), epilepsy: 0.276 umol/g/min (SD 0.115)] (P[lt]0.005)].
CONCLUSIONS: Synthesis of glutamine from glutamate in glial cells is considered to be increased in epileptic brains.
[Supported by: Health Science Research Grants; Research on Brain Science Project, and National Research and Development Program for Medical and Welfare Apparatus under entrustment by NEDO, Japan]