Calbindin immunoreactive GABAergic neurons in paralimbic temporal neocortex of major depression patients with resistant temporal lobe epilepsy

ACUÑA A, PABLO VAZQUEZ , KONOPKA HECTOR, SEOANE P, FABIAN LOIDL, KOCHEN S, D?ALESSIO

Congreso; international epilepsy congress; 2017

IntroductionResistant temporal lobe epilepsy (RTLE) is associated with a high prevalence of comorbid depression. Alterations in GABAergic system has been suggested to play an important role for development and spread of seizures in patients with RTLE and there are evidence that it is also affected in depression. The aim of this study was to determine a subgroup of GABAergic interneurons which express the calcium binding protein calbindin (CB), in the temporal pole resected during surgery, in patients with RTLE and hippocampal sclerosis (HE) with and without comorbid depression. MethodsPatient with RTLE and HE were included. Neurological, neuropsychological, psychiatric (SCID I, DSMIV) and complementary evaluations (VIDEO EEG, RMN) were conducted before surgery (anterior temporal lobectomy). Depression was considered when patients have at least one depressive episode codified in Axis I of DSM IV. The cortical sections from medial part of temporal pole resected during surgery, were processed by histopathological routine techniques, and by immunohistochemistry with anti- CB and anti- NeuN antibodies. Neocortex samples with focal cortical dysplasias were excluded. Post mortem sections were processed simultaneously. A quantitative morphometric analysis was conducted (Image J). ANOVA/Bonferroni tests were used. Results. Patients with RTLE and co-morbid depression n=9 (age 30 ± 10 years), and without depression n=6 (age 36 ± 9 years) and 5 matched postmortem controls were included. In patients with co-morbid depression the total number of CB interneurons and the reactive area in layer II, were significantly reduced (ANOVA F (2,17) = 5.536, p=0,014), figure 1b. No significant differences in the the number of Neun cells were found (ANOVA F (2,14)= 0,550 p=0,588) , figure 2b.ConclusionsIn this preliminary sample comorbid depression in RTLE patients was associated with a reduction in the total number of CB interneurons in temporal area suggesting alterations in inhibitory GABAergic system. These areas are involved in sensory integration and codification of affective stimuli. Further studies should be performed to confirm and extend this preliminary findings.