Abstracts

Rationale: Recent evidences suggest various types of hippocampal plasticity in the epilepsy. Although the patterns of cell genesis, cell death, or granule cell dispersion have been described in the rodent model of epilepsy, little data so far ascertained those in the human hippocampus.Methods: In this study, we attempted to examine the histological changes in the hippocampi of epilepsy patients (n=26) undergoing the surgical intervention due to intractability, in terms of cell genesis, cell death and granule cell dispersion. We performed prox-1 (granule cell marker), Nissl staining (neuronal profiles), and nestin (immature neural progenitor marker) immunostaining for the analysis of granule cell dispersion, neuronal loss, and cell genesis, respectively. The presence of Nestin-positive cells in the granule cell layer correlated to the severity of hippocampal granule cell dispersion. Results: Nestin-positive cells were distributed across the whole dispersed granule cell layers (dentate gyrus). Cell genesis was related to the history of febrile convulsion and frequent generalized tonic-clonic seizures that might indicate an injury-associated cell proliferation. However, the cell genesis was independent of the degree of neuronal loss, mean seizure frequency, onset age, and disease duration.Conclusions: In conclusion, cell genesis may lead to granule cell dispersion, but cell genesis is not invariably associated with hippocampal sclerosis, and seizure phenotypes.