Neurogenesis in temporal lobe epilepsy: relationship between histological findings and changes in dentate gyrus proliferative properties.
OBJECTIVE
The relationship between hippocampal histopathological abnormalities, epileptogenesis and neurogenesis remains rather unclear.


METHODS
Tissue samples including the subgranular zone of dentate gyrus (DG) were freshly collected for tissue culture for neurospheres generation in 16 patients who underwent surgery for drug-resistant temporal lobe epilepsy. Remaining tissues were histologically examined to assess the presence of mesial temporal sclerosis (MTS) and focal cortical dysplasia.


RESULTS
MTS was detected in 8 cases. Neurospheres were formed in 10/16 cases. Only three out of these 10 cases exhibited MTS; on the contrary 5/6 cases lacking neurosphere proliferation presented MTS. There was a significant correlation between presence of MTS and absence of proliferation (p = 0.0389). We also observed a correlation between history of febrile seizures (FS) and presence of MTS (p = 0.0004) and among the 6 cases lacking neurosphere proliferation, 4 cases (66.6%) had experienced prolonged FS. Among "proliferating" cases the percentage of granular cells pathology (GCP) was lower (20% vs 50%) compared to "non proliferating" cases.


CONCLUSIONS
A decreased potential to generate neurosphere from the SGZ is related to MTS and to alterations of dentate gyrus granule cells, especially in MTS type 1b and GCP type 1. These histological findings may have different prognostic implications, regarding seizure and neuropsychological outcome, compared to patients with other epileptogenic lesions (such as FCD, glioneuronal tumours, vascular lesions).
Section of Pathology, Department of Hematology and Oncology of the University of Bologna, Bellaria Hospital, Bologna, Italy. gianluca.marucci@ausl.bologna.it
Gianluca
G
Marucci
Marco
M
Giulioni
Guido
G
Rubboli
Michela
M
Paradisi
Mercedes
M
Fernández
Giovanna
G
Del Vecchio
Eugenio
E
Pozzati
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002449:Cell Aggregation; D049109:Cell Proliferation; D018891:Dentate Gyrus / Q000473:pathology*; D004833:Epilepsy, Temporal Lobe / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D055495:Neurogenesis; D019635:Neurosurgical Procedures; D012598:Sclerosis / Q000473:pathology; D003294:Seizures, Febrile / Q000150:complications; D055815:Young Adult