Characterization of endogenous stem cells within endosseous wounds

描述(申请人提供)：鉴于骨创伤、癌症以及成人和先天性疾病的高发病率，北美每年有超过500,000例骨移植手术，因此骨是仅次于血液的最常见的移植组织也就不足为奇了。除了传统的骨移植修复缺陷外，还有许多临床应用可以受益于骨再生疗法，包括重建颞颌关节以缓解约9000万美国人的颌痛，以及在重建的颅面骨内恢复轮廓和形状。间充质干细胞和祖细胞(MSPC)被认为在骨再生过程中发挥着重要作用，但对其侵袭受损或病变组织的情况知之甚少。到目前为止，还没有研究研究内源性间充质干细胞和祖细胞(MSPC)在骨内创面再生过程中的时空分布。这种特征对于开发依赖于这些细胞的招募(即通过输送生长因子)或使用外源性干细胞或祖细胞来源的治疗策略可能是至关重要的。此外，植入或注射支架或水凝胶基质对骨髓间充质干细胞迁移和分化的影响尚不清楚。在这里，我们的目标是表征内源性MSPC在以不同速度再生的缺损区内迁移和分化的时空分布，这将有助于为我们的实验室建立核心动物模型。这将被用来询问涉及骨髓间充质干细胞在受损或患病骨组织再生中的各种途径。目的1：研究非临界大小骨缺损骨内愈合过程中骨髓间充质干细胞迁移和分化的时空特征。这将通过首先用纯化的MSPC群体在体外验证抗体，然后通过免疫组织化学分析MSPC在大鼠非临界大小的骨内缺损中的迁移和分化来实现。目的：研究内源性骨髓间充质干细胞的时空迁移和分化在植入生物材料后是否发生改变，从而显著延缓骨再生。 公共卫生相关性：现有的颅面部骨缺损再生的临床策略，包括功能缺陷和严重的美学畸形，都充满了许多局限性。我们的目标是描述内源性间充质干细胞和祖细胞在以不同速度再生的缺损区内迁移和分化的时空分布。这将有助于创建一个核心动物模型，我们可以利用该模型来开发基于利用间充质干细胞的再生能力来增强骨再生的新策略。

DESCRIPTION (provided by applicant): Given the high incidence of bone trauma, cancer, and adult and congenital disease, which is associated with over 500,000 bone graft procedures each year in North America, it is not surprising that bone is the most common transplanted tissue, second only to blood. In addition to traditional bone grafting for defects, there are numerous clinical applications that can benefit from bone regeneration therapies including temporomandibular joint reconstruction to alleviate jaw pain which affects an estimated 90 million Americans, and restoration of contour and shape within reconstructed craniofacial bone. Mesenchymal stem and progenitor cells (MSPCs) are believed to play an important role during bone regeneration, however very little is known regarding their invasion into damaged or diseased tissue. To date there are no studies that examine the temporal and spatial distribution of endogenous mesenchymal stem and progenitor cells (MSPCs) during endosseous wound regeneration. Such characterization may be critical to developing therapeutic strategies that rely on recruitment of these cells (i.e., via delivery of growth factors) or the use of an exogenous source of stem or progenitor cells. Additionally, the impact of implanting or injecting scaffolds or hydrogel matrices on the migration and differentiation of MSPCs is unknown. Here we aim to characterize the spatial-temporal profile of endogenous MSPC migration and differentiation within defects that regenerate at different rates that will facilitate the creation of a core animal model for our laboratory. This will be used to interrogate various pathways involving MSPCs in regeneration of damaged or diseased bone tissue. AIM 1: To characterize the spatial and temporal aspects of MSPC migration and differentiation during endosseous wound healing within non-critical size defects. This will be accomplished through first validating antibodies in vitro with purified populations of MSPCs, followed by immunohistochemical analysis of MSPC migration and differentiation within a rat non-critical sized endosseous defect. AIM 2: To determine if the spatial-temporal migration and differentiation of endogenous MSPCs changes upon implantation of biomaterial matrices which significantly delay bone regeneration. Public Health Relevance: Existing clinical strategies for regeneration of craniofacial bone defects including functional deficits and severe aesthetic deformities are fraught with many limitations. We aim to characterize the spatial-temporal profile of endogenous mesenchymal stem and progenitor cell migration and differentiation within defects that regenerate at different rates. This will facilitate the creation of a core animal model that we can use to develop new strategies for enhancing bone regeneration based on harnessing the regenerative capacity of mesenchymal stem cells.