Aquaporin-4 contributes to the resolution of peritumoural brain oedema in human glioblastoma multiforme after combined chemotherapy and radiotherapy.
Brain tumour oedema is coupled with blood-brain barrier damage and alteration in water flow. Aquaporin-4 (AQP4) is involved in the development and resolution of brain oedema, and it is strongly upregulated in glioblastoma multiforme (GBM). Here, we evaluated AQP4 expression and content in GBM and correlated with VEGF-VEGFR-2 expression. In the relapse after chemotherapy and radiotherapy, AQP4 content reduced in parallel with VEGF-VEGFR-2, as compared with primary tumours, and in the peripheral areas of relapsed tumours AQP4 mimicked normal findings of perivascular rearrangement. After immunogold electron microscopy, gold particles were attached on the glial membrane facing the perivascular side, likewise AQP4 gold labelling of the vessels of the control areas. In primary tumours the peripheral vessels appeared faintly marked by AQP4, while the perivascular tumour cells showed a strong expression. The vasculature of the inner tumour areas was unlabelled by AQP4, while tumour cells were labelled, in both primary and relapsing tumours. Relapsed tumours after radiotherapy alone showed slight AQP4 reduction and perivascular restoring in the peripheral areas of the tumour. These data indicate that in GBM chemotherapy and radiotherapy induce a down-regulation in AQP4 expression restoring its perivascular rearrangement suggesting its potential role in the resolution of brain oedema.
Nico
Beatrice
B
Department of Human Anatomy and Histology, Piazza Giulio Cesare, 11, Policlinico I-70124 Bari, Italy. nico@histology.uniba.it
Mangieri
Domenica
D
Tamma
Roberto
R
Longo
Vito
V
Annese
Tiziana
T
Crivellato
Enrico
E
Pollo
Bianca
B
Maderna
Emanuela
E
Ribatti
Domenico
D
Salmaggi
Andrea
A
D051401:Aquaporin 4 / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D001812:Blood-Brain Barrier / Q000378:metabolism* / Q000473:pathology; D001834:Body Water / Q000378:metabolism; D001929:Brain Edema / Q000378:metabolism* / Q000473:pathology; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D002199:Capillary Permeability; D002560:Cerebrovascular Circulation; D003131:Combined Modality Therapy; D015536:Down-Regulation / Q000187:drug effects / Q000528:radiation effects; D005909:Glioblastoma / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D006801:Humans; D015854:Up-Regulation; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D042442:Vascular Endothelial Growth Factors / Q000378:metabolism
D051401:Aquaporin 4; D042442:Vascular Endothelial Growth Factors; D040301:Vascular Endothelial Growth Factor Receptor-2