Directed Differentiation of Human Mesenchymal Stem Cells for Bone Repair

人间充质干细胞定向分化用于骨修复

• 批准号: 7144909
• 负责人: JAN P. STEGEMANN
• 金额: $ 32.21万
• 依托单位: RENSSELAER POLYTECHNIC INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7144909
• 关键词: birth; bone; culture; extracellular; growth factor; human; osteocytes; phenotype; proteins; stem cells; tissue engineering

DESCRIPTION (provided by applicant): The long-term objective of this project is to create new bone graft materials based on the directed differentiation of adult human mesenchymal stem cells (hMSC) in defined three-dimensional (3D) microenvironments, which can be delivered as a paste directly to the site of bone repair. hMSC are a promising autogenous cell source for bone tissue engineering because of their demonstrated ability to proliferate, as well as to clearly differentiate into the osteogenic lineage. A main factor limiting their use in bone repair is the inability to reliably control the induction and maintenance of osteogenic differentiation. This project directly addresses this issue by carefully controlling the extracellular environment immediately surrounding hMSC, by embedding them in protein hydrogel beads (20-200 um in diameter) of defined extracellular matrix (ECM) and growth factor composition. The central hypothesis is that hMSC differentiation can be directed through structural and compositional changes in the cellular microenvironment. The combination of specific integrin binding to natural ECM proteins and highly efficient, local delivery of growth factors in a 3D microenvironment is expected to provide a potent stimulus for osteogenic differentiation of hMSC. The Specific Aims of this project are to: 1] identify 3D extracellular microenvironment formulations that consistently promote differentiation of hMSC towards the osteogenic phenotype, 2] augment the extracellular microenvironment with BMP-2, a growth factor known to have potent osteoinductive effects, 3] adapt the use of defined cellular microenvironments to high density culture, and test them as an injectable cell delivery system in vitro, and 4] test 3D matrix-embedded hMSC in vivo in a segmental defect model in immunodeficient rats. The approach of creating defined 3D bead microenvironments addresses four key elements that are critical to effective bone repair: i] the presence of living osteogenic cells (hMSC), ii] an osteoinductive scaffold (the natural ECM proteins collagen I and vitronectin), iii] osteoinductive growth factors to provide signals to the resident cells (BMP-2), and iv] an adequate blood supply to support cell growth and function (by providing void spaces between beads for vascular ingrowth and VEGF delivery in vivo). This project is aimed at clinical problems that can benefit from therapies that accelerate bone healing in a difficult environment, such as avascular necrosis, spinal fusion and implant fixation. It will yield fundamental knowledge of how hMSC phenotype can be controlled by the 3D extracellular environment, and will therefore have broad impact on regenerative medicine. In the field of orthopaedic tissue engineering, it will yield a new cell-based bone repair therapy.

描述（由申请人提供）：该项目的长期目标是基于定义的三维（3D）微环境的成年人类间充质干细胞（HMSC）的定向分化，可以创建新的骨移植物材料，这些微环境可以直接作为糊剂传递到骨修复的部位。 HMSC是骨组织工程的有前途的自源细胞来源，因为它们具有增殖能力，并且可以清楚地分化为成骨谱系。限制其在骨修复中使用的主要因素是无法可靠地控制成骨分化的诱导和维持。该项目通过仔细控制HMSC周围周围的细胞外环境直接解决了这一问题，将它们嵌入定义的细胞外基质（ECM）和生长因子组成的蛋白质水凝胶珠（直径为20-200 um）中。中心假设是HMSC分化可以通过细胞微环境中的结构和组成变化引导。在3D微环境中，特定整合素与天然ECM蛋白的结合与高效的生长因子的局部递送的结合预计将为HMSC的成骨分化提供有效的刺激。 The Specific Aims of this project are to: 1] identify 3D extracellular microenvironment formulations that consistently promote differentiation of hMSC towards the osteogenic phenotype, 2] augment the extracellular microenvironment with BMP-2, a growth factor known to have potent osteoinductive effects, 3] adapt the use of defined cellular microenvironments to high density culture, and test them as an injectable cell体外递送系统和4]在免疫缺陷大鼠中的分段缺陷模型中测试3D矩阵嵌入的HMSC。 The approach of creating defined 3D bead microenvironments addresses four key elements that are critical to effective bone repair: i] the presence of living osteogenic cells (hMSC), ii] an osteoinductive scaffold (the natural ECM proteins collagen I and vitronectin), iii] osteoinductive growth factors to provide signals to the resident cells (BMP-2), and iv] an adequate blood supply支持细胞的生长和功能（通过在体内提供血管向内生长和VEGF递送的珠子之间的空间）。该项目针对的是在艰难环境中加速骨骼愈合的疗法，例如血管坏死，脊柱融合和植入物固定。它将产生有关如何通过3D细胞外环境控制HMSC表型的基本知识，因此将对再生医学产生广泛的影响。在骨科组织工程领域，它将产生新的基于细胞的骨修复疗法。