In 129J mice, female donor hearts were heterotopically transplanted into C57/B16 males and treated with soluble VEGF receptor 1 (sVEGFR1) or vehicle control. The effect of VEGF inhibition on BM-mediated microvascular outgrowth and endothelial cell migration and proliferation were assessed using in vitro assays of aortic ring angiogenesis, wound healing and proliferation, respectively.
At 21 days post-transplantation, treatment with sVEGFR1 significantly reduced both percent luminal narrowing (p < 0.05) and percent of vessels affected (p < 0.005). sVEGFR1 significantly reduced average wet heart weight (p < 0.05), whereas mean ventricular cross-sectional area remained similar. Treatment of aortic rings with both sVEGFR1 and VEGFR2 tyrosine phosphorylation inhibitor (Ki 8751) significantly reduced BM-mediated microvascular outgrowth length (p < 0.05) and area (p < 0.05). Treatment of human coronary artery endothelial cells with sVEGFR1 and Ki 8751 significantly reduced BM-mediated endothelial cell migration (p < 0.005) and proliferation (p < 0.05).
VEGF inhibition reduces the severity and incidence of CAV in mouse models of cardiac transplantation, while attenuating myocardial edema and neo-angiogenesis. Using this model, we provide in vitro evidence of the role of VEGF signaling in BM-mediated microvascular outgrowth and endothelial cell migration and proliferation. VEGF inhibition may represent a novel approach to CAV treatment and prevention.