Calbindin immunoreactivity of GABAergic interneurons patients with resistant temporal lobe epilepsy and epilepsy surgery

KONOPKA H, ESCOBAR E, SEOANE P, LOIDL F, KOCHEN S, D' ALESSIO L.; ACUÑA A, VAZQUEZ P, LOIDL F

Congreso; 32 ND INTERNACIONAL EPILEPSY CONGRESS; 2017

IntroductionResistant temporal lobe epilepsy (RTLE) is associated with a high prevalence of comorbid depression. Alterations in GABAergic system have been suggested to play an important role for development and spread of seizures in patients with RTLE and there is evidence that 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 temporal 20 and 21 Brodman neocortical areas of patients with RTLE and hippocampal sclerosis (HE) with and without comorbid depression, who underwent epilepsy surgery. 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). The cortical sections from 20 and 21 Brodman areas, were processed by histopathological routine techniques, and by immunohistochemistry with anti- CB and anti- NeuN. Focal dyplasias were excluded. Post mortem sections were processed simultaneously. A quantitative morphometric analysis was conducted (Image J). ANOVA/Bonferroni test 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). No significant differences in the groups in the number of neuN cells were found in layer II (ANOVA F (2,14)= 0,550 p=0,588).Conclusion:Comorbid depression in RTLE patients was associated with a reduction in the total number of CB interneurons in temporal areas, which are involved in sensory integration and codification of affective stimuli, suggesting alterations in inhibitory GABAergic system. Further studies should been performed to confirm and extend this preliminary findings.