Extensive in vivo angiogenesis following controlled release of human vascular endothelial cell growth factor:: Implications for tissue engineering and wound healing
Extensive in vivo angiogenesis following controlled release of human vascular endothelial cell growth factor:: Implications for tissue engineering and wound healing
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DOI：
10.1046/j.1525-1594.2001.025007558.x
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发表时间：
2001-07-01
影响因子：
2.4
通讯作者：
Gitnick, T
中科院分区：
文献类型：
--
作者：
Elçin, YM;Dixit, V;Gitnick, T
血管内皮细胞生长因子（VEGF）对血管生成有强烈的刺激作用。尽管VEGF非常有效，但由于其半衰期短，且在采用不受控制和非特异性的方法给药时会迅速降解；而且，大剂量全身给药会产生有害的副作用。控释技术能够在较长时间内释放所需水平的具有生物活性的VEGF，并能更广泛地研究该化合物在体内的作用。本研究的目的是确定海藻酸钙微球中VEGF的体外释放行为，以及这种控释系统在促进大鼠模型皮下部位局部新生血管形成方面的效力。在25℃的静态条件下，对人VEGF(165)（2和4μg/cm³微球）的体外释放进行了为期3周的研究，并使用竞争性酶免疫测定法测量每日的激素释放量。在最初4天内出现不受控制的释放之后，从负载2和4μg/cm³聚合物的微球中分别实现了相当稳定的零级VEGF释放，释放量为每天50 - 90纳克和70 - 120纳克。对体内血管生成进行了为期8周的研究，并使用免疫过氧化物酶染色和组织病理学测量方法进行评估。对大鼠（n = 24）的体内研究表明，从第1周开始，植入VEGF微球的大鼠在上腹部腹股沟筋膜处形成了相当程度的毛细血管网络。在植入含4μg VEGF的微球3周后的组中观察到最广泛的新生血管形成；8周后血管化程度相当相似。对照组没有血管生成的迹象，VEGF诱导的新生血管形成的差异具有统计学意义（p < 0.03）。标本的免疫染色显示人VEGF的释放与新生血管形成之间有很强的关联。此处描述的VEGF控释系统促进了强烈的血管生成，可应用于组织工程和伤口愈合研究。
Vascular endothelial cell growth factor (VEGF) has strong stimulating effects on vascularization. Though very potent, VEGF is rapidly degraded due to its short half-life and when administrated by uncontrolled and nonspecific methods; however, its systemic administration in large doses can cause harmful side effects. Controlled release technology would allow delivering desired levels of bioactive VEGF within extended periods and permit examination of the in vivo effects of the compound in a broader way. The objective, of this study was to determine the in vitro release behavior of VEGF from calcium alginate microspheres and the potency of this controlled release system in promoting localized neovascularization at the subcutaneous site of the rat model. In vitro release of human VEGF(165) (2 and 4 mug/cm(3) microsphere) was studied for 3 weeks under static conditions at 25 degreesC, and daily hormone release was measured using a competitive enzyme immunoassay. Following an uncontrolled release within the first 4 days, a quite constant zero-order VEGF release of 50 to 90 and 70 to 120 ng/day was achieved from 2 and 4 mug/cm(3) polymer loaded microspheres respectively. In vivo angiogenesis was studied for a period of 8 weeks and evaluated using immunoperoidase staining and histopathological measurements. In vivo studies with rats (n = 24) showed a considerable level of capillary network formation at the epigastric groin fascia of VEGF microsphere-implanted rats starting from the first week. The most extensive neovascularization was observed in the group with 3 week postimplanted 4 mug VEGF containing microspheres; this level of vascularization was quite similar after 8 weeks. While the control group showed no evidence of angiogenesis, the difference in VEGF-induced neovascularization is statistically significant (p < 0.03). Immunostaining of the specimens showed a strong relationship between the release of human VEGF and neovascularization. The controlled VEGF release system described here promotes vigorous angiogenesis and has applicability for tissue engineering and wound healing studies.