Angiogenesis and Brain Oedema in Intracranial Meningiomas: Influence of Vascular Endothelial Growth Factor

Abstract

The correlation between angiographic neovascularization, peritumoural brain oedema (PTBOe) and the expression of vascular endothelial growth factor (VEGF), was analysed in 30 patients with intracranial meningiomas. Pre-operative angiograms were examined for the existence of either an exclusively dural tumour blush or an additionally pial tumour supply from cerebral arteries. Furthermore the presence of macroscopic tumour-neovascularization and dysplastic changes of tumour-draining cerebral veins was evaluated. VEGF expression was investigated on histological tissue samples, using immunohistochemical techniques. VEGF immunohistochemistry and neuroradiological evaluations were performed in double blind fashion. Tumour volume and the amount of oedema were calculated by computerized tomography (CT) or magnetic resonance imaging (MRI). The oedema-tumour volume ratio was defined as oedema index (OeI). Compared to VEGF-negative meningiomas, tumours with striking VEGF staining revealed a significant higher mean oedema index (OeI = 4.2 vs. OeI = 1.5; p < 0.018), and a higher oedema incidence (91.7% vs. 44.4%; p < 0.046). Equally, meningiomas with additionally tumour supply from cerebral arteries were associated with a significant higher mean OeI (OeI = 4.1 vs. OeI = 1.2; p < 0.01) and oedema incidence (94.7% vs. 20.0%; p < 0.0023) than meningiomas with exclusively tumour supply from dural arteries. All meningiomas with striking VEGF-expression were associated with vascular tumour supply from cerebral arteries, but VEGF-negative tumours only in 50% (p < 0.029). These data suggest a link between VEGF-expression, arterial tumour supply and peritumoural brain oedema. The development of tumour supply from cerebral arteries may be important for formation of meningioma-related oedema. Therefore, VEGF may represent a potent mediator in the evolution of this type of vascularization in meningiomas.

Proliferation potential of spinal meningiomas

“…The higher degree of calcification in intracranial compared to spinal meningiomas might be due to the longer tumor growth-tumor detection interval in intracranial tumors, as spinal meningiomas can lead to neurological deficits while still relatively small. Neo-angeogenetic activity of meningiomas might account for higher proliferation in these tumors as reflected by higher Ki-67 expression [3,10,30]. The semiquantitative subjective evaluation of the vascularity in our series seems to agree with these data.…”

Assessment of Angiographic Vascularity of Meningiomas with Dynamic Susceptibility Contrast-Enhanced Perfusion-Weighted Imaging and Diffusion Tensor Imaging

“…It has been found to correlate with microvascular proliferation [19][20][21][22] and vascular endothelial growth factor expression, a major regulator of tumor angiogenesis. 23 In meningiomas, both angiographic vascularity 24 and CBV 25 correlated with vascular endothelial growth factor expression. Therefore, it is not surprising when there is a positive correlation between CBV and angiographic vascularity in meningiomas, as demonstrated in the present study.…”

Ekstraaksiyel Beyin Tumorleri

“…Ekstraaksiyel lokalizasyonlarına rağmen menenjiomlarda beyin ödemi nadir değildir (Resim 7) [19]. Elektron mikroskop incelemelerde ve difüzyon ağırlıklı görüntülerde beyin öde-minin vazojenik olduğu tespit edilmiştir.…”

“…VEGF'in indüklediği pial damarlanma ve tümör vaskülaritesinin peritümöral beyin ödemi ile ilişkili olduğu sanıl-maktadır. Pial damarlarda proliferasyon olması ve araknoid membrandan geçerek menenjioma uzanması sonucu beyin bariyeri bozulur ve beyne menenjiom invazyonu olur [19,24,25]. Tümör vaskülaritesi de ödem boyutu ile koreledir.…”