Therapeutic angiogenesis using noble human VEGF-E chimeric genes and autologous bone marrow mononuclear cells

背景血管内皮生长因子-A(VEGF-A)可促进血管生成，但也会引起水肿或组织炎症等不良反应。在Orf病毒基因组中发现的血管内皮生长因子-E与血管内皮生长因子受体-2特异性结合，并在内皮细胞上显示有丝分裂活性。最近，我们创造了两种形式的VEGF-E和人胎盘生长因子(P1GF)嵌合体基因(VEGF-E嵌合体#9和VEGF-E嵌合体#33)，它们都是人源化的基因，具有VEGF-E功能，但抗原性较弱。4种表达载体(pCDNA3.1-LacZ、phVEGF-A、pVEGF-Echiera#9和pVEGF-Echiera#33，n=8)应用于大鼠后肢缺血模型。与对照pCDNA3.1-LacZ治疗组相比，pVEGF-E嵌合体#9、pVEGF-E嵌合体#33或phVEGF-A均显著增加缺血/正常后肢血流量的比率。碱性磷酸酶组织化学染色也显示，与pCDNA3.1-LacZ处理组相比，pVEGF-Echiera#9、pVEGF-Echiera#33或phVEGF-A组的毛细血管密度均增加。结论新型VEGF-E/人P1GF嵌合体基因pVEGF-E/人P1GF嵌合体基因pVEGF-Echiera#9和pVEGF-Echiera#33可显著刺激组织缺血后血管生成，其程度与phVEGF-A相似，但炎症反应较小。

BackgroundVascular endothelial growth factor-A (VEGF-A) promotes angiogenesis but causes adverse side effects such as edema or tissue inflammation. VEGF-E, found in the genome of the Orf virus, specifically binds to VEGF receptor-2 and shows mitotic activity on endothelial cells. Recently, we created two forms of VEGF-E and human placental growth factor (P1GF) chimera genes (VEGF-E chimera #9 and VEGF-E chimera #33), which are humanized genes holding VEGF-E function but less antigenicity.Methods and ResultsWe examined potential proangiogenic activities of these chimera genes. Four types of expression plasmids (pCDNA3.1-LacZ, phVEGF-A, pVEGF-Echimera#9 and pVEGF-Echimera#33, n=8 each) were administered in a rat model of hindlimb ischemia. Either pVEGF-E chimera #9, pVEGF-E chimera #33 or phVEGF-A significantly increased the ratio of ischemic/normal hindlimb blood-flow compared to the control pCDNA3.1-LacZ treated group. Histochemical staining by alkaline phosphatase also revealed that either pVEGF-Echimera#9, pVEGF-Echimera#33 or phVEGF-A increased the capillary density compared to the pCDNA3.1-LacZ treated group. Furthermore, immunostaining for anti-ED1 revealed that lower number of macrophages were infiltrated in both pVEGF-Echimera#9 and pVEGF-Echimera#33 groups compared to the phVEGF-A group.ConclusionsNovel VEGF-E/human P1GF chimera genes, pVEGF-Echimera#9 and pVEGF-Echimera#33, significantly stimulated angiogenesis in response to tissue ischemia, whose extent was almost identical to that induced by phVEGF-A with less tissue inflammation responses.