PT  - JOURNAL ARTICLE
AU  - Abramovitch, Rinat
AU  - Dafni, Hagit
AU  - Smouha, Eitzik
AU  - Benjamin, Laura E.
AU  - Neeman, Michal
TI  - <em>In Vivo</em> Prediction of Vascular Susceptibility to Vascular Endothelial Growth Factor Withdrawal
DP  - 1999 Oct 01
TA  - Cancer Research
PG  - 5012--5016
VI  - 59
IP  - 19
4099  - http://cancerres.aacrjournals.org/content/59/19/5012.short
4100  - http://cancerres.aacrjournals.org/content/59/19/5012.full
SO  - Cancer Res1999 Oct 01; 59
AB  - One of the hallmarks of tumor neovasculature is the prevalence of immature vessels manifested by the low degree of recruitment of vascular mural cells such as pericytes and smooth muscle cells. This difference in the architecture of the vascular bed provides an important therapeutic window for inflicting tumor-selective vascular damage. Here we demonstrate the application of gradient echo magnetic resonance imaging (MRI) for noninvasive in vivo mapping of vascular maturation, manifested by the ability of mature vessels to dilate in response to elevated levels of CO2. Histological α-actin staining showed a match between dilating vessels detected by MRI and vessels coated with smooth muscle cells. Switchable, vascular endothelial growth factor (VEGF)-overexpressing tumors (C6-pTET-VEGF rat glioma s.c. tumors in nude mice) displayed high vascular function and significant vascular damage upon VEGF withdrawal. However, damage was restricted to nondilating vessels, whereas mature dilating tumor vessels were resistant to VEGF withdrawal. Thus, MRI provides in vivo visualization of vascular maturity and prognosis of vascular obliteration induced by VEGF withdrawal.