Related Experiment Video
Updated: Jan 2, 2026
In Vivo Fiber-Coupled Pre-Clinical Confocal Laser-scanning Endomicroscopy pCLE of Hippocampal Capillaries in Awake Mice
Published on: April 21, 2023
Microgliosis is associated with visual memory decline in patients with temporal lobe epilepsy and hippocampal
Eliana Cristina de Brito Toscano1, Érica Leandro Marciano Vieira2, Ana Carolina Diniz Carvalho Portela3
1Departamento de Patologia Geral do Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Neuroscience Division, Interdisciplinary Laboratory of Medical Investigation, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Abstract:
Hippocampal sclerosis (HS) is characterized by neuronal loss and gliosis. The intensity and distribution of these histopathological findings over the Cornu Ammonis (CA) subfields are important for the classification of HS and prognostication of patients with temporal lobe epilepsy (TLE). Several studies have associated the neuronal density reduction in the hippocampus with cognitive decline in patients with TLE. The current study aimed at investigating whether the expression of glial proteins in sclerotic hippocampi is associated with presurgical memory performance of patients with TLE. Before amygdalohippocampectomy, patients were submitted to memory tests. Immunohistochemical and morphometric analyses with glial fibrillary acidic protein (GFAP) for astrogliosis and human leucocyte antigen DR (HLA-DR) for microgliosis were performed in paraffin-embedded HS and control hippocampi. Sclerotic hippocampi exhibited increased gliosis in comparison with controls. In patients with TLE, the area and intensity of staining for HLA-DR were associated with worse performance in the memory tests. Glial fibrillary acidic protein was neither associated nor correlated with memory test performance. Our data suggest association between microgliosis, but not astrogliosis, with visual memory decline in patients with TLE.
Insights
Microgliosis, an increase in immune cells in the brain, is linked to memory decline in temporal lobe epilepsy (TLE) patients with hippocampal sclerosis (HS). Astrogliosis, another glial response, showed no association with memory deficits.
Area of Science:
- Neuroscience
- Neuropathology
- Epilepsy Research
Background:
- Hippocampal sclerosis (HS) involves neuronal loss and gliosis, impacting Cornu Ammonis (CA) subfields.
- Reduced hippocampal neuronal density correlates with cognitive decline in temporal lobe epilepsy (TLE).
Purpose of the Study:
- To investigate the association between glial protein expression in sclerotic hippocampi and presurgical memory performance in TLE patients.
Main Methods:
- Immunohistochemical and morphometric analyses of glial fibrillary acidic protein (GFAP) for astrogliosis and human leucocyte antigen DR (HLA-DR) for microgliosis.
- Performed analyses on paraffin-embedded HS and control hippocampi.
- Assessed presurgical memory performance using memory tests before amygdalohippocampectomy.
Main Results:
- Sclerotic hippocampi showed increased gliosis compared to controls.
- Higher area and intensity of HLA-DR staining correlated with poorer memory test performance in TLE patients.
- GFAP expression was not associated with memory test performance.
Conclusions:
- Microgliosis, indicated by HLA-DR expression, is associated with visual memory decline in TLE patients.
- Astrogliosis (GFAP) is not linked to memory deficits in this patient cohort.
- Findings highlight the differential role of glial responses in TLE-associated memory impairment.
