Article
Morphological changes of astrocytes and new appearance of radial glia in hippocampi of patients suffering from temporal lobe epilepsy
Morphologische Veränderungen von Astrozyten und Auftreten von Radialglia im Hippocampus von Patienten mit Temporallappen-Epilepsie
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Published: | April 23, 2004 |
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Outline
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Objective
Temporal lobe epilepsy (TLE) is frequently associated with a sclerosis of the hippocampus, also known as Ammon’s horn sclerosis (AHS). These hippocampi show a significant neuron loss with astrogliosis. In the recent literature, the most attention was paid to neuronal changes. However, these hippocampi show complex remodelling of synapses and neuronal layers, as a widening of the usually very slim granule cell layer (GCL dispersion) which might be influenced by the change of the glial matrix.
Methods
Hippocampal specimens were obtained from hippocampi of patients treated for pharmaceutically intractable TLE (n=12) and from patients with intracerebral tumours, who served as controls (n=3). The GCL dispersion and the back-grown mossy fibres of the two groups were compared with immunhistochemistry against glial fibrillary acid protein (GFAP) and Silver-Impregnations. The astrocytes were reconstructed and the morphology was evaluated by an optical analysis system (Neurolucida).
Results
Astrocytes proximal to the granule cell layer display a change of their processes. The usually star-like shape of the processes changed into longer processes projecting vertically through the dispersed GCL. Some radial glia cells were observed projecting also vertical to GCL.
Conclusions
Hippocampi of patients with AHS demonstrate a change of the glial scaffold and a new appearance of progenitor cells which project vertically through the GCL along the embryonal sprouting direction of neurons in the hippocampus.