Tonello Sarah, Moore Marc C, Sharma Blanka, Dobson Jon, McFetridge Peter S
J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, JG-56 Biomedical Sciences Building, P.O. Box 116131, Gainesville, FL, 32611-6131, USA.
Department of Materials Science and Engineering, University of Florida, Gainesville, FL, 32611, USA.
Drug Deliv Transl Res. 2016 Apr;6(2):174-83. doi: 10.1007/s13346-016-0281-3.
A significant hurdle limiting musculoskeletal tissue regeneration is the inability to develop effective vascular networks to support cellular development within engineered constructs. Due to the inherent complexity of angiogenesis, where multiple biochemical pathways induce and control vessel formation, our laboratory has taken an alternate approach using a matrix material containing angiogenic and osteogenic proteins derived from human placental tissues. Single bolus administrations of the human placental matrix (hPM) have been shown to initiate angiogenesis but vascular networks deteriorated over time. Controlled/sustained delivery was therefore hypothesized to stabilize and extend network formation. To test this hypothesis, hPM was encapsulated in degradable poly(lactic-co-glycolic acid) (PLGA) microparticles to extend the release period. Microparticle preparation including loading, size, encapsulation efficiency, and release profile was optimized for hPM. The angiogenic cellular response to the hPM/PLGA-loaded microparticles was assessed in 3D alginate hydrogel matrices seeded with primary human endothelial cells. Results show an average microparticle diameter of 91.82 ± 2.92 μm, with an encapsulation efficiency of 75%, and a release profile extending over 30 days. Three-dimensional angiogenic assays with hPM-loaded PLGA microparticles showed initial stimulation of angiogenic tubules after 14 days and further defined network formations after 21 days of culture. Although additional optimization is necessary, these studies confirm the effectiveness of a novel controlled multi-protein release approach to induce and maintain capillary networks within alginate tissue scaffolds.
限制肌肉骨骼组织再生的一个重大障碍是无法构建有效的血管网络来支持工程化构建物中的细胞发育。由于血管生成具有内在复杂性，多种生化途径诱导并控制血管形成，我们实验室采用了另一种方法，即使用一种含有源自人胎盘组织的血管生成和成骨蛋白的基质材料。已证明单次推注人胎盘基质（hPM）可启动血管生成，但随着时间推移血管网络会退化。因此，推测采用可控/持续释放方式可稳定并延长网络形成。为验证这一假设，将hPM封装在可降解的聚乳酸-乙醇酸共聚物（PLGA）微粒中以延长释放期。针对hPM对微粒制备过程进行了优化，包括负载、尺寸、包封效率和释放曲线。在用原代人内皮细胞接种的3D海藻酸盐水凝胶基质中评估了对负载hPM/PLGA微粒的血管生成细胞反应。结果显示微粒平均直径为91.82±2.92μm，包封效率为75%，释放曲线持续超过30天。用负载hPM的PLGA微粒进行的三维血管生成试验显示，培养14天后血管生成微管开始受到刺激，培养21天后网络形成更加明确。尽管还需要进一步优化，但这些研究证实了一种新型可控多蛋白释放方法在海藻酸盐组织支架内诱导和维持毛细血管网络的有效性。
