Division of Cardiology, Keenan Research Centre--Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Ontario, Canada.
J Am Coll Cardiol. 2012 Apr 3;59(14):1320-8. doi: 10.1016/j.jacc.2011.12.025.
The aim of this study was to compare temporally separated vascular endothelial growth factor (VEGF) and angiopoietin (Ang)-1 delivery with concomitant delivery or single VEGF delivery, for therapeutic angiogenesis in chronic ischemia.
Single gene delivery of VEGF results in immature neovessels that ultimately regress. Endogenously, VEGF acts early to initiate angiogenesis, whereas Ang-1 acts later to induce vessel maturation. Timing VEGF and Ang-1 gene delivery to mimic endogenous angiogenesis might be more effective for sustained neovascularization.
Unilateral hindlimb ischemia was induced in 170 rats. Ultrasound-mediated gene delivery was performed with cationic microbubbles and plasmid deoxyribonucleic acid. Groups included VEGF at 2 weeks, VEGF/Ang-1 at 2 weeks, VEGF at 2 weeks with Ang-1 at 4 weeks, and untreated control subjects. At 2, 4, and 8 weeks after ligation, blood flow and flow reserve (FR) were assessed by contrast-enhanced ultrasound. Vascular density, organization, and supporting cell coverage were assessed by fluorescent microangiography and immunohistochemistry.
In untreated control subjects, blood flow, FR, and vessel density remained reduced. The VEGF delivery improved flow and vessel density at 4 weeks; however, FR remained low, supporting cell coverage was poor, and flow and vessel density regressed by 8 weeks. The VEGF/Ang-1 co-delivery marginally increased flow and vessel density; however, FR and supporting cell coverage improved. After temporally separated VEGF and Ang-1 delivery, blood flow, vessel density, and FR increased and were sustained, with improved pericyte coverage at 8 weeks.
In conclusion, temporally separated VEGF and Ang-1 gene therapy results in sustained and functional neovascularization.
本研究旨在比较血管内皮生长因子（VEGF）和血管生成素（Ang）-1的时间分离递送与同时递送或单独 VEGF 递送，以用于慢性缺血中的治疗性血管生成。
VEGF 的单一基因递送会导致不成熟的新生血管最终退化。内源性地，VEGF 早期起作用以启动血管生成，而 Ang-1 则起作用以诱导血管成熟。模拟内源性血管生成来定时 VEGF 和 Ang-1 基因递送可能更有效地维持新生血管化。
在 170 只大鼠中诱导单侧后肢缺血。通过超声介导的阳离子微泡和质粒脱氧核糖核酸进行基因递送。实验组包括：2 周时的 VEGF、2 周时的 VEGF/Ang-1、2 周时的 VEGF 加 4 周时的 Ang-1 和未处理的对照组。在结扎后 2、4 和 8 周，通过对比增强超声评估血流和血流储备（FR）。通过荧光微血管造影和免疫组织化学评估血管密度、组织和支持细胞覆盖。
在未处理的对照组中，血流、FR 和血管密度仍然降低。VEGF 递送在 4 周时改善了血流和血管密度；然而，FR 仍然较低，支持细胞覆盖不良，血流和血管密度在 8 周时退化。VEGF/Ang-1 共递送略微增加了血流和血管密度；然而，FR 和支持细胞覆盖得到改善。在 VEGF 和 Ang-1 的时间分离递送后，血流、血管密度和 FR 增加并持续增加，8 周时周细胞覆盖得到改善。
总之，VEGF 和 Ang-1 的时间分离基因治疗可导致持续和功能性的新生血管形成。
