Pathophysiologic characteristics of balloon cells in cortical dysplasia.
OBJECTIVE
Balloon cells are histopathological hallmarks of cortical malformations, i.e., focal cortical dysplasia (FCD) of the Taylor type or the cortical tubers of tuberous sclerosis, and they are believed to be the epileptogenic substrate and cause therapeutic drug resistant epilepsy in man. This study was carried out to investigate the developmental histogenesis and epileptogenesis of balloon cells in FCD.


METHODS
We used an immunohistochemical approach to examine the expressions of primitive neuroepithelial cell antigens (CD34, nestin, and vimentin), ionotrophic glutamate receptor subunits (NR1, NR2A/B, GluR1, GluR2, GluR3, GluR4, and GluR5/6/7), and P-glycoprotein in balloon cells from FCD and normal cerebral cortex epileptogenic lesions.


CONCLUSIONS
Balloon cells presented in clusters or as scattered cells throughout FCD lesions involving the gray and white matter. We found the balloon cells to be classifiable into three subtypes based on glial fibrillary acidic protein (GFAP) and neurofilament protein (NF-L) immunohistochemistry, i.e., as neuronal, astrocytic, and uncommitted. Immunopositivity for nestin, CD34, and vimentin in balloon cells of FCD suggests that they may be derived from the abnormal development and differentiation of neural stem cells. Moreover, it appears that epileptogenesis in cortical dysplasia is partly caused by the upregulations of some glutamate receptor subunit proteins (NR1, NR2A/B, GluR1, and GluR3) in balloon cells and dysplastic neurons. We speculate that the presence of the drug resistance protein P-glycoprotein in balloon cells might explain medically refractory epilepsy in FCD.
Oh
Hyun-Sik
HS
Department of Pathology, Chonnam National University Medical School and Center for Biomedical Human Resources (BK-21), 5 Hakdong, Dongku, Gwangju, 501-746, Korea.
Lee
Min-Cheol
MC
Kim
Hyung-Seok
HS
Lee
Ji-Shin
JS
Lee
Jae-Hyuk
JH
Kim
Myeong-Kyu
MK
Woo
Young-Jong
YJ
Kim
Jae-Hyoo
JH
Kim
Hyoung-Ihl
HI
Kim
Seung-Up
SU
D000293:Adolescent; D000328:Adult; D018952:Antigens, CD34 / Q000096:biosynthesis; D002454:Cell Differentiation; D019070:Cell Lineage; D002648:Child; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000096:biosynthesis; D008297:Male; D054220:Malformations of Cortical Development / Q000378:metabolism* / Q000473:pathology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D064231:Nestin; D016900:Neurofilament Proteins / Q000096:biosynthesis; D009457:Neuroglia / Q000166:cytology / Q000473:pathology; D009474:Neurons / Q000166:cytology / Q000473:pathology; D017470:Receptors, Glutamate / Q000378:metabolism; D013234:Stem Cells / Q000473:pathology; D014746:Vimentin / Q000096:biosynthesis
D018952:Antigens, CD34; D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D016900:Neurofilament Proteins; D017470:Receptors, Glutamate; D014746:Vimentin