gms | German Medical Science

64th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

26 - 29 May 2013, Düsseldorf

Balloon cells in the epileptogenic human cortex of focal cortical dysplasia type 2b

Meeting Abstract

  • Julia M. Nakagawa - Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg; Abteilung Experimentelle Epilepsieforschung, Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg
  • Susanne Fauser - Klinik für Neurologie, Epileptologie, Universitätsklinikum Ulm
  • Catharina Donkels - Abteilung Experimentelle Epilepsieforschung, Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg
  • Jan Beckervordersandforth - Abteilung für Pathologie, Universität Maastricht, Niederlande
  • Marco Prinz - Abteilung für Neuropathologie, Universitätsklinikum Freiburg
  • Josef Zentner - Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg
  • Carola Haas - Abteilung Experimentelle Epilepsieforschung, Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg

Deutsche Gesellschaft für Neurochirurgie. 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Düsseldorf, 26.-29.05.2013. Düsseldorf: German Medical Science GMS Publishing House; 2013. DocP 074

doi: 10.3205/13dgnc491, urn:nbn:de:0183-13dgnc4919

Published: May 21, 2013

© 2013 Nakagawa et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: Focal cortical dysplasia (FCD), a malformation of cerebrocortical development, is regarded as a major cause of pharmaco-resistant focal epilepsy thus frequently becoming object to neurosurgical treatment. Severe focal cortical dysplasia (FCD 2b) is characterized by distinct cortical dyslamination, dysmorphic neurons and balloon cells (BC). However, little is known about the cellular identity of BC, their intercellular interactions and possible impact on epileptogenicity. An approach to a structural and morphological characterization of BC and their potential cellular integration in a severely dysplastic, epileptogenic cortex is subject of the current study.

Method: Layer-specific protein expression (Reelin, Calbindin, SMI32, Parvalbumin, TLE4) and inhibitory interneuron status (GAD65/67) were studied by immunohistological techniques including double immunolabeling. N=29 specimens with neuropathologically confirmed FCD 2b were analyzed, in addition analysis of neuronal stem cell marker expression (Oct4, SOX2, c-myc, Vimentin, Nestin) in n=3 specimens was carried out; the findings were compared to a control group with (n=6) and without epilepsy (n=4 post mortem). Cortical neuronal fiber structure was visualized by Bielschowsky silver staining. Statistical analysis following quantification of layer-specific neuronal subpopulations and BC and morphological study of stem cell marker expression in BC was performed.

Results: Using lamina-specific markers we found that BC can be located all over the dysplastic cortex without a lamina of preference. Moreover, morphological study suggests that BC intercommunicate with cortical neurons and receive inhibitory input. Furthermore, BC show pluripotent stem cell marker expression: Whereas a colocalization of the analyzed stem cell marker expression was observed for Vimentin, Nestin, SOX2 and c-myc, there was a cellular subpopulation solely immunopositive for Oct4.

Conclusions: Our findings suggest that a migration disorder underlying the layer-unspecific cortical localization of BC is unlikely. Moreover, we observed signs of intercellular interaction of BC that still have to be analyzed in detail. In addition, there is evidence of an activation of the mTORC1 cascade resulting in an upregulation of pluripotent stem cell markers in BC. The marker expression pattern characterizes subpopulations of BC possibly indicating a differing level of differentiation or cellular identity.