Inflammatory reactions in human medial temporal lobe epilepsy with hippocampal sclerosis

A Crespel, P Coubes, MC Rousset, C Brana, A Rougier… - Brain research, 2002 - Elsevier
A Crespel, P Coubes, MC Rousset, C Brana, A Rougier, G Rondouin, J Bockaert
Brain research, 2002Elsevier
Many experimental studies suggest that NFκB, a transcription factor involved in acute
inflammation, and cytokines participate in neuronal excitability and/or glial scar formation in
epilepsy. In this report, we looked for the expression of NFκB in hippocampi surgically
removed in patients with medial temporal lobe epilepsy (MTLE) and hippocampal sclerosis
(HS) who had an history of febrile convulsions. We analyzed 18 hippocampi from epileptic
patients with MTLE and HS, and we used as control specimens three hippocampi from non …
Many experimental studies suggest that NFκB, a transcription factor involved in acute inflammation, and cytokines participate in neuronal excitability and/or glial scar formation in epilepsy. In this report, we looked for the expression of NFκB in hippocampi surgically removed in patients with medial temporal lobe epilepsy (MTLE) and hippocampal sclerosis (HS) who had an history of febrile convulsions. We analyzed 18 hippocampi from epileptic patients with MTLE and HS, and we used as control specimens three hippocampi from non-epileptic patients and four hippocampi from patients with cryptogenic MTLE without HS. We used antibodies raised against the NFκB-p65 subunit and we identified glial cells with specific antibodies. Hippocampi from patients with MTLE and HS displayed severe neuronal loss surrounded by gliosis in CA1 area and more or less in CA3/CA4 areas. Double immunolabeling showed that reactive astrocytes of lesioned areas over-expressed NFκB-p65 (significantly when compared to control specimens). Moreover, some surviving pyramidal neurons in these areas and numerous dentate granule cells were strongly positive for NFκB-p65 in cytoplasm and nucleus, whereas control hippocampi showed a faint basal cytoplasmic staining in neurons. These results suggest that in epileptic hippocampi with typical sclerosis, inflammatory processes are chronically active or transiently re-induced by recurrent seizures. Whether NFκB over-expression reflects protective or deleterious mechanisms in the epileptic focus remains to be elucidated.
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