Densities of parvalbumin-immunoreactive neurons in non-malformed hippocampal sclerosis-temporal neocortex and in cortical dysplasias.
The changes in density of inhibitory parvalbumin-immunoreactive interneurons were quantitatively studied by immunohistochemistry in a series of human neocortical samples comprising the spectrum of malformations of cortical development (MCD) encountered in epilepsy surgery and the non-malformed hippocampal sclerosis-temporal neocortex in patients with refractory temporal lobe epilepsy. The highest relative density of parvalbumin-immunoreactive cells was obtained in the control samples (n = 21). The number of parvalbumin-immunoreactive neurons was significantly decreased in non-malformed hippocampal sclerosis-temporal neocortex (n = 73, 80.5% of control values). In a proportion of the latter samples as well as in two controls we observed patchy regions of absence of parvalbumin staining. The total counts of parvalbumin-immunoreactive cells in all the categories of MCD - "mild MCD" (n = 25), focal cortical dysplasia type I (n = 19) and type II (n = 15) - were decreased representing 72.4%, 55.0% and 12.2% of control values, respectively. Significantly different parvalbumin-immunoreactive cell densities were demonstrated between the focal cortical dysplasia types IIA and IIB. In "mild MCD", we observed a more pronounced decrease of parvalbumin-immunoreactive cells in the infragranular layers. No significant differences were revealed between the temporal and extratemporal examples of analogous MCD types. This study provides evidence for reduction of inhibitory parvalbumin-immunoreactive interneurons in the epileptic neocortex affected by MCD as well as in morphologically unaffected epileptic temporal neocortex, thus representing a possible mechanism for their epileptogenicity.
Zamecnik
J
J
Department of Pathology and Molecular Medicine, Charles University, 2nd Medical Faculty, V Uvalu 84, 150 06 Prague, Czech Republic. josef.zamecnik@lfmotol.cuni.cz
Krsek
P
P
Druga
R
R
Marusic
P
P
Benes
V
V
Tichy
M
M
Komarek
V
V
D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D002452:Cell Count; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004827:Epilepsy / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D004833:Epilepsy, Temporal Lobe / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D005260:Female; D005911:Gliosis / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006624:Hippocampus / Q000002:abnormalities / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007395:Interneurons / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009421:Nervous System Malformations; D010320:Parvalbumins / Q000378:metabolism*; D013702:Temporal Lobe / Q000002:abnormalities / Q000378:metabolism / Q000473:pathology*
D015415:Biomarkers; D010320:Parvalbumins