Abstracts

Rationale: Tau protein, one of the microtubule-associated proteins, plays an important role in assembly of tubulin monomers into microtubules and in maintaining the cytoskeleton and axonal transport. Tau protein in CSF as a marker for neuronal/axonal damage and degenerations has already been studied in several neurological disorders such as Alzheimer’s disease, stroke, Creutzfeldt-Jacob disease, amyotrophic lateral sclerosis, and multiple sclerosis. However, little has been known about tau protein changes in epileptic conditions. In this study, we measure the tau protein in CSF to determine whether it could be useful to monitor the neuronal damage in convulsive status epilepticus in childhood. Methods: Two clinical categories exhibiting febrile convulsive status epilepticus were highlighted in this study. One was “febrile convulsion status (FC status)”, and the other was “acute infantile encephalopathy predominantly affecting the frontal lobes (AIEF)”. The former is defined in here as febrile convulsion lasting for over 30 minutes, having the recovery of consciousness within 24 hours and no subsequent neurological sequelae. The latter category is recently described acute encephalopathy syndrome, characterized by the neurological manifestations suggesting frontal lobe dysfunctions and the radiological features showing selective involvement of the cerebral cortex predominantly distributed in the frontal lobes (Yamanouchi H and Mizuguchi M. Epilepsy Res 2006). Lumber CSF samples were colleted from 15 patients with FC status and 7 patients with AIEF. Tau level was measured using and ELISA kit, Fino Scholar hTAU (Innogenetics, Ghent, Belgium). For statistical analysis, Mann-Whitney test was used to investigate differences between groups.Results: In FC status, the median and mean values of tau protein were 178 and178 pg/ml in CSF samples taken within 24 hrs (n=11), 233 and 314 pg/ml between 24-48hrs (n=3) after the status. The tau protein levels between these two groups are statistically significant (p<0.05). The values of the CSF sample taken between 48-72 hrs (n=1) in one patient with FC status were 470 and 470 pg/ml. In contrast, the median and mean values of tau protein in CSF of patients with AIEF were markedly elevated; 736 and 1,628 pg/ml within 24 hrs (n=3), 1,160 and 2,865 pg/ml between 24-48 hrs (n=3) after the status. In the extremely severe case of AIEF, tau protein in CSF at the 6 day after the status was elevated up to 56,100 pg/ml. Tau levels in CSF taken within 24 hrs from patients with AIEF was higher than those from patients with FC status (p<0.01).Conclusions: According to this preliminary study, it could be suggested as following: 1) Tau protein level in CSF increase with the course of time after the febrile convulsive status epilepticus, 2) Tau protein level in CSF of patients with AIEF is markedly elevated even at the early period after the onset. (Supported by grants from NCNP, Ministry of Health, Labor and Welfare, Japan)