title: A VEGF165-induced phenotypic switch from increased vessel density to increased vessel diameter and increased endothelial NOS activity.
abstract: Although vascular endothelial growth factor-165 (VEGF(165)) regulates numerous angiogenic cellular activities, its complex effects on vascular morphology are not highly quantified. By fractal-based, multiparametric branching analysis of 2D vascular pattern in the quail chorioallantoic membrane (CAM), we report that vessel density increased maximally at lower VEGF concentrations, but that vessel diameter and activity of endothelial nitric oxide synthase (eNOS) increased maximally at higher VEGF concentrations. Following exogenous application of human VEGF(165) to the CAM at embryonic day 7, vessel density and diameter were measured after 24 h at arterial end points by the fractal dimension (D(f)) and generational branching parameters for vessel area density (A(v)), vessel length density (L(v)) and vessel diameter (D(v)) using the computer code VESGEN. The VEGF-dependent phenotypic switch from normal vessels displaying increased vessel density to abnormal, dilated vessels typical of tumor vasculature and other pathologies resulted from an approximate threefold increase in VEGF concentration (1.25 to 5 microg/CAM) and correlated positively with increased eNOS activity. Relative to control specimens, eNOS activity increased maximally to 60% following VEGF treatment at 5 microg/CAM, compared to 10% at 1.25 microg/CAM, and was accompanied by no significant change in activity of inducible NOS. In summary, VEGF(165) induced a phenotypic switch from increased vessel density associated with low VEGF concentration, to increased vessel diameter and increased eNOS activity at high VEGF concentration.
authors.affiliation: Biological Fluid Physics, NASA Glenn Research Center, Cleveland, OH 44135, USA. patricia.parsons@grc.nasa.gov
authors.forename: Patricia
authors.initials: P
authors.lastname: Parsons-Wingerter
authors.forename: Unni M
authors.initials: UM
authors.lastname: Chandrasekharan
authors.forename: Terri L
authors.initials: TL
authors.lastname: McKay
authors.forename: Krishnan
authors.initials: K
authors.lastname: Radhakrishnan
authors.forename: Paul E
authors.initials: PE
authors.lastname: DiCorleto
authors.forename: Brian
authors.initials: B
authors.lastname: Albarran
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Farr
mesh_terms: D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000196:embryology / Q000502:physiology; D049033:Chorioallantoic Membrane / Q000098:blood supply* / Q000187:drug effects / Q000201:enzymology; D003370:Coturnix; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*
chemical_list: D011994:Recombinant Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D052250:Nitric Oxide Synthase Type III