Frontiers in Integrative Neuroscience (Nov 2021)

Do Hippocampal Neurons Really Count for Comorbid Depression in Patients With Mesial Temporal Lobe Epilepsy and Hippocampal Sclerosis? A Histopathological Study

  • Nathália Stela Visoná de Figueiredo,
  • Anaclara Prada Jardim,
  • Lenon Mazetto,
  • Jeana Torres Corso Duarte,
  • Sandra Mara Comper,
  • Neide Barreira Alonso,
  • Maria Helena da Silva Noffs,
  • Carla Alessandra Scorza,
  • Esper Abrão Cavalheiro,
  • Ricardo Silva Centeno,
  • Gerardo Maria de Araújo Filho,
  • Elza Márcia Targas Yacubian

DOI
https://doi.org/10.3389/fnint.2021.747237
Journal volume & issue
Vol. 15

Abstract

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Depression is the most frequent psychiatric comorbidity seen in mesial temporal lobe epilepsy (MTLE) patients with hippocampal sclerosis (HS). Moreover, the HS is the most frequent pathological hallmark in MTLE-HS. Although there is a well-documented hippocampal volumetric reduction in imaging studies of patients with major depressive disorder, in epilepsy with comorbid depression, the true role of the hippocampus is not entirely understood. This study aimed to verify if patients with unilateral MTLE-HS and the co-occurrence of depression have differences in neuronal density of the hippocampal sectors CA1–CA4. For this purpose, we used a histopathological approach. This was a pioneering study with patients having both clinical disorders. However, we found no difference in hippocampal neuronal density when depression co-occurs in patients with epilepsy. In this series, CA1 had the lowest counting in both groups, and HS ILAE Type 1 was the most prevalent. More studies using histological assessments are needed to clarify the physiopathology of depression in MTLE-HS.

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