Ex vivo study of dentate gyrus neurogenesis in human pharmacoresistant temporal lobe epilepsy.
OBJECTIVE
Neurogenesis in adult humans occurs in at least two areas of the brain, the subventricular zone of the telencephalon and the subgranular layer of the dentate gyrus in the hippocampal formation. We studied dentate gyrus subgranular layer neurogenesis in patients subjected to tailored antero-mesial temporal resection including amygdalohippocampectomy due to pharmacoresistant temporal lobe epilepsy (TLE) using the in vitro neurosphere assay.


METHODS
Sixteen patients were enrolled in the study; mesial temporal sclerosis (MTS) was present in eight patients. Neurogenesis was investigated by ex vivo neurosphere expansion in the presence of mitogens (epidermal growth factor + basic fibroblast growth factor) and spontaneous differentiation after mitogen withdrawal. Growth factor synthesis was investigated by qRT-PCR in neurospheres.


RESULTS
We demonstrate that in vitro proliferation of cells derived from dentate gyrus of TLE patients is dependent on disease duration. Moreover, the presence of MTS impairs proliferation. As long as in vitro proliferation occurs, neurogenesis is maintained, and cells expressing a mature neurone phenotype (TuJ1, MAP2, GAD) are spontaneously formed after mitogen withdrawal. Finally, formed neurospheres express mRNAs encoding for growth (vascular endothelial growth factor) as well as neurotrophic factors (brain-derived neurotrophic factor, ciliary neurotrophic factor, glial-derived neurotrophic factor, nerve growth factor).


CONCLUSIONS
We demonstrated that residual neurogenesis in the subgranular layer of the dentate gyrus in TLE is dependent on diseases duration and absent in MTS.
Paradisi
M
M
BioPharmaNet-DIMORFIPA, and Department of Histology, Embryology and Applied Biology, University of Bologna, Via Tolara di Sopra 50, Bologna, Italy.
Fernández
M
M
Del Vecchio
G
G
Lizzo
G
G
Marucci
G
G
Giulioni
M
M
Pozzati
E
E
Antonelli
T
T
Lanzoni
G
G
Bagnara
G P
GP
Giardino
L
L
Calzà
L
L
D000293:Adolescent; D000328:Adult; D049109:Cell Proliferation; D018891:Dentate Gyrus / Q000473:pathology / Q000503:physiopathology*; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000166:cytology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012598:Sclerosis / Q000473:pathology