Bone Tissue Engineerig: Effect of Dynamic Perfusion

骨组织工程：动态灌注的影响

• 批准号: 7471894
• 负责人: Aaron Sanford Goldstein
• 金额: $ 16.54万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7471894
• 关键词: Angiogenic Factor; Annual Reports; Area; Autologous; BMP2 gene; Biocompatible Materials; Bioluminescence; Blood Vessels; Bone Morphogenetic Proteins; Bone Regeneration; Bone Substitutes; Bone Tissue; Bone Transplantation; Cell Survival; Cells; Cellular biology; DNA Binding; Defect; Deposition; Devices; Engineering; Family; Gene Expression; Gene Silencing; Gene Targeting; Genes; Goals; Gold; Growth; Healed; Image; In Situ; In Vitro; Infiltration; Innate Bone Remodeling; Luciferases; MAPK14 gene; Manufactured Materials; Measures; Mitogen-Activated Protein Kinases; Modality; Molecular; Molecular Probes; Monitor; Nutrient; Outcome; Oxygen; Patients; Perfusion; Phosphorylation; Procedures; Proteins; Public Health; Pulsatile Flow; RNA Interference; Rate; Repair Material; Reporter; Reporter Genes; Research Personnel; Research Project Grants; Role; Sales; Signal Pathway; Signal Transduction; Site; Small Interfering RNA; Source; Standards of Weights and Measures; Stem cells; Stimulus; System; Technology; Testing; Tissue Engineering; Tissues; Transactivation; Transcription Factor AP-1; Translations; Transplantation; Treatment Protocols; Validation; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; X-Ray Computed Tomography; bone; bone morphogenetic protein 2; bone morphogenetic protein 7; design; fluid flow; gene induction; healing; implantation; in vivo; innovation; insight; molecular imaging; novel; reconstruction; repaired; response; scaffold; size; stem

DESCRIPTION (provided by applicant): Successful healing of critical-sized bone defects requires the implantation of a bioactive material that is capable of stimulating vascular infiltration, tissue integration, and normal bone remodeling. To date, engineered tissues consisting of progenitor cells cultured within porous scaffolds have not been as effective as pharmacologic agents for the repair of bone defects, and we postulate that this stems from an insufficient deposition of bioactive factors during in vitro culture. We propose that in vitro perfusion culture of osteoprogenitor cells remains a promising means for achieving clinically effective materials, but that culture strategies conducive to the deposition of osteogenic and angiogenic factors must be identified. Recently, we have found that expression of the osteogenic factor bone morphogenetic protein (BMP)-2 and the angiogenic factor vascular endothelial growth factor (VEGF)-A are induced by perfusion, and that BMP-2 expression in particular is sensitive to pulsatile perfusion. This indicates that mechanotransductive signaling regulates induction of this important bioactive factor, and points to a need to understand the underlying signaling mechanisms, which then may be harnessed to produce bioactive materials. Therefore, the goals of this project are 1) to probe the mechanisms by which pulsatile flow induces expression of BMPs and VEGF-A, and 2) to implement a non-destructive imaging modality to monitor expression of BMP-2 in perfused porous scaffolds. We emphasize that this project will focus on the induction of BMP-2, 4, and 7 and VEGF-A by pulsatile flow. The specific aims of this two-year project are: 1) Determine the effect of pulsatile flow regimens on the induction of BMPs and VEGF, and the activation of discrete signaling pathways. 2) Determine the role of molecular signaling through p38 on the induction of BMPs. 3) Implement bioluminescence computed tomography to image BMP-2 expression in perfused scaffolds. This multi-disciplinary research project integrates tissue engineering, molecular cell biology, and imaging both to advance our fundamental understanding of mechanotransductive signaling pathways, and to develop an enabling technology for tissue engineering. These goals are applied to bone tissue engineering, but have broad applicability to all areas of tissue engineering. The innovative components of this project include planar and 3D perfusion devices to activate mechanotransductive signaling, siRNA technology to probe signaling pathways, and bioluminescence computed tomography to monitor gene induction. PUBLIC HEALTH RELEVANCE Autologous bone graft transplanted from one site in the patient to another is the gold standard material for repair of critical-sized defects, but limited tissue availability and concerns of donor-site complications drive a growing demand for bone substitutes for reconstructive procedures. Sales of bone substitutes were estimated to total $900 million worldwide in 2005, with an annual grows rate of 10% [1]. Recently, orthobiologic materials have emerged as a promising alternative to conventional synthetics, and have a projected growth rate of 74% annually. These materials consist of bioactive proteins that stimulate integration, vascular infiltration, and tissue remodeling embedded within conventional biomaterials (e.g., Infuse Bone Graft, OP-1 Putty [2, 3]). We have extensive evidence that a tissue engineering approach involving culturing of osteoprogenitor cells in porous scaffolds under dynamic perfusion can be used to create a bioactive material (containing osteogenic and angiogenic factors) that may be a tractable alternative to current orthobiologics. The goals of this project are to probe the underlying molecular mechanisms by which perfusion regulates the synthesis of this bioactive matrix, and to develop a non-destructive molecular imaging modality to monitor this synthesis. 1. Artimplant. http://www.artimplant.se/investors/annual_reports. 2005. 2. http://www.fda.gov/cdrh/MDA/DOCS/h020008.html. OP-1 Putty - H020008. 2004. 3. http://www.fda.gov/cdrh/mda/docs/p000058.html. InFUSE" Bone Graft/LT-CAGE" Lumbar Tapered Fusion Device - P000058. 2002.

描述（由申请方提供）：成功愈合临界尺寸骨缺损需要植入能够刺激血管浸润、组织整合和正常骨重塑的生物活性材料。迄今为止，工程组织 由在多孔支架内培养的祖细胞组成 对于骨缺损的修复，这些药物不如药物有效，我们推测这是由于体外培养过程中生物活性因子沉积不足所致。我们建议，在体外灌注培养的骨祖细胞仍然是一个有前途的手段，为实现临床有效的材料，但培养策略，有利于沉积成骨和血管生成因子必须加以确定。最近，我们发现成骨因子骨形态发生蛋白（BMP）-2和血管生成因子血管内皮生长因子（VEGF）-A的表达是由灌注诱导的，并且BMP-2的表达尤其对脉动灌注敏感。这表明机械转导信号调节这种重要的生物活性因子的诱导，并指出需要了解潜在的信号机制，然后可以利用这些机制来生产生物活性材料。因此，本项目的目标是：1）探索脉动流诱导BMP和VEGF-A表达的机制，以及2）实施非破坏性成像模式来监测灌注多孔支架中BMP-2的表达。我们强调，这个项目将集中在诱导BMP-2，4和7和VEGF-A的脉动流。这一为期两年的项目的具体目标是： 1)确定脉动流方案对BMP和VEGF的诱导以及离散信号传导通路的激活的影响。2)确定通过p38的分子信号传导对BMP诱导的作用。3)实施生物发光计算机断层扫描成像灌注支架中的BMP-2表达。 这个多学科的研究项目整合了组织工程，分子细胞生物学和成像，以推进我们对机械转导信号通路的基本理解，并开发组织工程的使能技术。这些目标适用于骨组织工程，但对组织工程的所有领域具有广泛的适用性。该项目的创新组件包括激活机械传导信号的平面和3D灌注设备，探测信号通路的siRNA技术，以及监测基因诱导的生物发光计算机断层扫描。 公共卫生相关性自体骨移植物从患者的一个部位移植到另一个部位是修复关键尺寸缺损的金标准材料，但有限的组织可用性和对供体部位并发症的担忧推动了对骨替代物的需求不断增长。据估计，2005年全球骨替代品的销售总额为9亿美元，年增长率为10% [1]。最近，骨科生物材料已成为传统合成材料的一种有前途的替代品，预计每年的增长率为74%。这些材料由生物活性蛋白质组成 刺激整合、血管浸润和组织重塑 嵌入常规生物材料（例如，注入植骨，OP-1油灰[2，3]）。我们有大量的证据表明，一种组织工程方法，包括在动态灌注下在多孔支架中培养骨祖细胞，可用于创造一种生物活性材料（含有成骨和血管生成因子），这可能是一种易于处理的替代目前的orthobiologics。该项目的目标是探索灌注调节这种生物活性基质合成的潜在分子机制，并开发一种非破坏性分子成像模式来监测这种合成。 1. Artimplant http://www.artimplant.se/investors/annual_reports. 2005. 2. http://www.fda.gov/cdrh/MDA/DOCS/h020008.html. OP-1油灰-H 020008。2004. 3. http://www.fda.gov/cdrh/mda/docs/p000058.html. InFUSE”植骨/LT-CAGE”腰椎锥形融合器- P000058。2002.