Glial cell changes in the white matter in temporal lobe epilepsy

Temporal lobe gliosis and neuronal loss are pathological hallmarks of complex partial seizures. However, the specificity of glial cell changes is not clear. To assess this we studied surgically resected temporal lobes containing either medial temporal sclerosis (MTS) or temporal lobe epilepsy with tumour (TLET) and compared them with idiopathic epilepsy cases and normal controls. We quantitatively assessed glial cell density and mean nuclear volume in the white matter of various temporal gyri and the deep white matter. There was an increase in mean glial cell nuclear volume in MTS and TLET cases in the white matter of superior temporal gyrus, parahippocampal gyrus and deep white matter but not in the white matter of the middle temporal gyrus. In contrast, the densities of glial cells immunopositive for glial fibrillary acidic protein in the MTS and TLET groups were reduced in all white matter regions when compared with the controls. These changes may indicate that glial cells in the white matter have an active role to play in epilepsy pathogenesis.