Different aquaporin-4 expression in glioblastoma multiforme patients with and without seizures.
Aquaporin-4 (AQP-4), the most important water channel in the brain, is expressed by astrocyte end feet abutting microvessels. Altered expression levels of AQP-4 and redistribution of the protein throughout the membranes of cells found in glioblastoma multiforme (GBM) lead to development of the edema often found surrounding the tumor mass. Dysregulation of AQP-4 also occurs in hippocampal sclerosis and cortical dysplasia in patients with refractory partial epilepsy. This work reports on analysis of the relationship between AQP-4 expression and the incidence of epileptic seizures in patients with GBM. Immunohistochemical and polymerase chain reaction techniques were used to evaluate AQP-4 in biopsy specimens from 19 patients with GBM, 10 of who had a history of seizures before surgery. AQP-4 mRNA levels were identical in the two groups of patients, but AQP-4 expression was more frequently detected on the GBM membranes from specimens of patients with seizures than from individuals without (10 versus 2, P < 0.001). We conclude that reduced expression of cell surface AQP-4 is characteristic of GBM patients without seizures, likely attributable to a posttranslational mechanism.
Unit of Clinical Neurophysiology, Department of Neurosurgery, CTO Hospital, Torino, Italy. gianlucaisoardo@yahoo.it
Gianluca
G
Isoardo
Isabella
I
Morra
Giulia
G
Chiarle
Valentina
V
Audrito
Silvia
S
Deaglio
Antonio
A
Melcarne
Carola
C
Junemann
Michele
M
Naddeo
Maurizio
M
Cogoni
Maria Consuelo
MC
Valentini
Andrea
A
Limberti
Federico
F
Faccani
Fabio
F
Malavasi
Giuliano
G
Faccani
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051401:Aquaporin 4 / Q000235:genetics* / Q000378:metabolism*; D001929:Brain Edema / Q000150:complications / Q000235:genetics / Q000473:pathology; D001932:Brain Neoplasms / Q000150:complications / Q000235:genetics / Q000473:pathology; D003710:Demography; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000150:complications* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012640:Seizures / Q000150:complications* / Q000473:pathology
C496030:AQP4 protein, human; D051401:Aquaporin 4