TY - JOUR
T1 - Monitoring of the biological response to murine hindlimb ischemia with 64Cu-labeled vascular endothelial growth factor-121 positron emission tomography
AU - Willmann, Jürgen K.
AU - Chen, Kai
AU - Wang, Hui
AU - Paulmurugan, Ramasamy
AU - Rollins, Mark
AU - Cai, Weibo
AU - Wang, David S.
AU - Chen, Ian Y.
AU - Gheysens, Olivier
AU - Rodriguez-Porcel, Martin
AU - Chen, Xiaoyuan
AU - Gambhir, Sanjiv S.
PY - 2008/2
Y1 - 2008/2
N2 - BACKGROUND - Vascular endothelial growth factor-121 (VEGF121), an angiogenic protein secreted in response to hypoxic stress, binds to VEGF receptors (VEGFRs) overexpressed on vessels of ischemic tissue. The purpose of this study was to evaluate Cu-VEGF121 positron emission tomography for noninvasive spatial, temporal, and quantitative monitoring of VEGFR2 expression in a murine model of hindlimb ischemia with and without treadmill exercise training. METHODS AND RESULTS - Cu-labeled VEGF121 and a VEGF mutant were tested for VEGFR2 binding specificity in cell culture. Mice (n=58) underwent unilateral ligation of the femoral artery, and postoperative tissue ischemia was assessed with laser Doppler imaging. Longitudinal VEGFR2 expression in exercised and nonexercised mice was quantified with Cu-VEGF121 positron emission tomography at postoperative day 8, 15, 22, and 29 and correlated with postmortem γ-counting. Hindlimbs were excised for immunohistochemistry, Western blotting, and microvessel density measurements. Compared with the VEGF mutant, VEGF121 showed specific binding to VEGFR2. Perfusion in ischemic hindlimbs fell to 9% of contralateral hindlimb on postoperative day 1 and recovered to 82% on day 29. Cu-VEGF121 uptake in ischemic hindlimbs increased significantly (P<0.001) from a control level of 0.61±0.17% ID/g (percentage of injected dose per gram) to 1.62±0.35% ID/g at postoperative day 8, gradually decreased over the following 3 weeks (0.59±0.14% ID/g at day 29), and correlated with γ-counting (R=0.99). Compared with nonexercised mice, Cu-VEGF121 uptake was increased significantly (P≤0.0001) in exercised mice (at day 15, 22, and 29) and correlated with VEGFR2 levels as obtained by Western blotting (R=0.76). Ischemic hindlimb tissue stained positively for VEGFR2. In exercised mice, microvessel density was increased significantly (P<0.001) compared with nonexercised mice. CONCLUSIONS - Cu-VEGF121 positron emission tomography allows longitudinal spatial and quantitative monitoring of VEGFR2 expression in murine hindlimb ischemia and indirectly visualizes enhanced angiogenesis stimulated by treadmill exercise training.
AB - BACKGROUND - Vascular endothelial growth factor-121 (VEGF121), an angiogenic protein secreted in response to hypoxic stress, binds to VEGF receptors (VEGFRs) overexpressed on vessels of ischemic tissue. The purpose of this study was to evaluate Cu-VEGF121 positron emission tomography for noninvasive spatial, temporal, and quantitative monitoring of VEGFR2 expression in a murine model of hindlimb ischemia with and without treadmill exercise training. METHODS AND RESULTS - Cu-labeled VEGF121 and a VEGF mutant were tested for VEGFR2 binding specificity in cell culture. Mice (n=58) underwent unilateral ligation of the femoral artery, and postoperative tissue ischemia was assessed with laser Doppler imaging. Longitudinal VEGFR2 expression in exercised and nonexercised mice was quantified with Cu-VEGF121 positron emission tomography at postoperative day 8, 15, 22, and 29 and correlated with postmortem γ-counting. Hindlimbs were excised for immunohistochemistry, Western blotting, and microvessel density measurements. Compared with the VEGF mutant, VEGF121 showed specific binding to VEGFR2. Perfusion in ischemic hindlimbs fell to 9% of contralateral hindlimb on postoperative day 1 and recovered to 82% on day 29. Cu-VEGF121 uptake in ischemic hindlimbs increased significantly (P<0.001) from a control level of 0.61±0.17% ID/g (percentage of injected dose per gram) to 1.62±0.35% ID/g at postoperative day 8, gradually decreased over the following 3 weeks (0.59±0.14% ID/g at day 29), and correlated with γ-counting (R=0.99). Compared with nonexercised mice, Cu-VEGF121 uptake was increased significantly (P≤0.0001) in exercised mice (at day 15, 22, and 29) and correlated with VEGFR2 levels as obtained by Western blotting (R=0.76). Ischemic hindlimb tissue stained positively for VEGFR2. In exercised mice, microvessel density was increased significantly (P<0.001) compared with nonexercised mice. CONCLUSIONS - Cu-VEGF121 positron emission tomography allows longitudinal spatial and quantitative monitoring of VEGFR2 expression in murine hindlimb ischemia and indirectly visualizes enhanced angiogenesis stimulated by treadmill exercise training.
KW - Angiogenesis
KW - Arteriosclerosis
KW - Exercise
KW - Growth substances
KW - Imaging
KW - Peripheral vascular disease
KW - Tomography
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U2 - 10.1161/CIRCULATIONAHA.107.733220
DO - 10.1161/CIRCULATIONAHA.107.733220
M3 - Article
C2 - 18250264
AN - SCOPUS:39449099278
SN - 0009-7322
VL - 117
SP - 915
EP - 922
JO - Circulation
JF - Circulation
IS - 7
ER -