title: Assessment of blood volume, vessel size, and the expression of angiogenic factors in two rat glioma models: a longitudinal in vivo and ex vivo study.
abstract: Assessment of angiogenesis may help to determine tumor grade and therapy follow-up. In vivo imaging methods for non-invasively monitoring microvasculature evolution are therefore of major interest for tumor management. MRI evaluation of blood volume fraction (BVf) and vessel size index (VSI) was applied to assess the evolution of tumor microvasculature in two rat models of glioma (C6 and RG2). The results show that repeated MRI of BVf and VSI - which involves repeated injection of an iron-based MR contrast agent - does not affect either the physiological status of the animals or the accuracy of the MR estimates of the microvascular parameters. The MR measurements were found to correlate well with those obtained from histology. They indicate that microvascular evolution differs significantly between the two glioma models, in good agreement with expression of angiogenic factors (vascular endothelial growth factor, angiopoietin-2) and with activities of matrix metalloproteinases, also assessed in this study. These MRI methods thus provide considerable potential for assessing the response of gliomas to anti-angiogenic and anti-vascular agents, in preclinical studies as well as in the clinic. Furthermore, as differences between the fate of tumor microvasculature may underlie differences in therapeutic response, there is a need for preclinical study of several tumor models.
authors.affiliation: Inserm, U836, Grenoble, France. Samvalable@hotmail.com
authors.forename: Samuel
authors.initials: S
authors.lastname: Valable
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lemasson
authors.forename: Régine
authors.initials: R
authors.lastname: Farion
authors.forename: Marine
authors.initials: M
authors.lastname: Beaumont
authors.forename: Christoph
authors.initials: C
authors.lastname: Segebarth
authors.forename: Chantal
authors.initials: C
authors.lastname: Remy
authors.forename: Emmanuel L
authors.initials: EL
authors.lastname: Barbier
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000032:analysis; D042501:Angiogenic Proteins / Q000032:analysis*; D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis; D001810:Blood Volume; D001932:Brain Neoplasms / Q000175:diagnosis / Q000503:physiopathology*; D045744:Cell Line, Tumor; D005910:Glioma / Q000175:diagnosis / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055806:Microvessels / Q000473:pathology* / Q000503:physiopathology*; D009363:Neoplasm Proteins / Q000032:analysis; D009389:Neovascularization, Pathologic / Q000175:diagnosis / Q000503:physiopathology*; D009929:Organ Size; D051381:Rats; D011916:Rats, Inbred F344; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D043925:Angiogenesis Inducing Agents; D042501:Angiogenic Proteins; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins