Injectable Anabolic Biomaterials for Bone Regeneration

描述（由申请人提供）：项目总结细胞移植正在成为一种有前途的临床策略，以加速组织再生。然而，这项技术的成功临床转化面临着一些工程和生物学挑战。主要的挑战在于我们无法在愈合部位输送和保留移植的细胞，并防止在受伤组织的不友好环境中不受控制的细胞死亡。我们实验室的长期目标是利用再生工程的原理，利用先进的生物材料和独特的细胞来源再生复杂的组织、器官和器官系统。我们的直接目标之一是设计细胞递送载体，其将在愈合部位短暂地充当有利的微环境以调节移植后的细胞性能。拟议的研究的目的是评估基于乳铁蛋白作为人工微环境的可注射生物材料的功效，以增加封装的大鼠间充质干细胞（rBMSC）的存活和成骨活性。该研究是基于我们的初步研究，证明了可溶性重组人乳铁蛋白（rhLf）的抗凋亡，促有丝分裂和成骨作用的基础上设计的。正在测试的假设是，注射用重组人乳铁蛋白凝胶（rhLfG）将通过抑制细胞凋亡和促进细胞增殖和成骨分化来提供有利的骨刺激微环境。实验计划将探索 基于可注射重组人乳铁蛋白凝胶的细胞递送载体通过两个特定目的。第一个目的是评价重组人乳铁蛋白凝胶（rhLfG）对大鼠骨髓间充质干细胞的体外抗凋亡、促有丝分裂和成骨作用。将使用已知诱导细胞凋亡的细胞培养条件。将使用可注射明胶凝胶作为对照基质，以评价乳铁蛋白凝胶的疗效 在改善细胞存活和促进细胞增殖和分化的微环境中。第二个目的是使用大鼠颅骨骨缺损模型评估可注射rhLfG在体内增强rBMSC存活、增殖和成骨的功效。我们假设，rhLfG提供的生物活性微环境将促进骨再生和更好的宿主组织整合后，rBMSC交付相比，可注射明胶运载工具。拟议的试点研究将有助于了解开发一种基于rhLf的细胞指导性可注射再生生物材料作为骨再生的细胞递送载体的可行性。如果成功，基于可注射乳铁蛋白的递送载体可以通过以下方式对基于细胞的治疗策略的临床转化产生显著影响： 解决其当前的一些局限性。 公共卫生相关性：骨髓间充质干细胞（BMSC）的移植在组织工程中具有巨大的潜力。然而，基于细胞的治疗策略在局部递送方面仍然带来重大的翻译挑战：不能将细胞保留在预期部位，不能维持细胞存活、细胞增殖和在损伤部位的改变的微环境中分化。这项拟议的研究旨在研究开发一种可注射再生生物材料的可行性，作为损伤部位的细胞友好型人工瞬时微环境， 克服与局部细胞递送相关的这些挑战中的一些。

DESCRIPTION (provided by applicant): PROJECT SUMMARY Cell transplantation is emerging as a promising clinical strategy to accelerate tissue regeneration. However, the successful clinical translation of this technology faces several engineering and biological challenges. Major challenges lies in our inability to deliver and retain the transplanted cells at the healing site and prevent the uncontrolled cell death in the unfriendly milieu of the injured tissue. The long-range goal of our laboratory is to regenerate complex tissues, organs and organ systems using the principles of regenerative engineering with advanced biomaterials and unique cell sources. One of our immediate objectives is to design cell delivery vehicles that will transiently act as a favorable microenvironment at the healing site to modulate cell performance upon transplantation. The aim of the proposed study is to evaluate the efficacy of an injectable biomaterial based on lactoferrin as an artificial microenvironment to increase the survival and osteogenic activity of encapsulated rat mesenchymal stem cells (rBMSC). The proposed research is designed based on our preliminary studies demonstrating the anti-apoptotic, mitogenic and osteogenic effect of soluble recombinant human lactoferrin (rhLf). The hypothesis being tested is that the injectable recombinant human lactoferrin gel (rhLfG) will present a favorable osteostimulative microenvironment by inhibiting cellular apoptosis and promoting cell proliferation and osteogenic differentiation. The experimental plan will explore the bioactivity of the injectable recombinant human lactoferrin gel based cell delivery vehicle through two specific aims. The first aim is designed to evaluate in vitro the anti apoptotic, mitogenic and osteogenic effect of recombinant human lactoferrin gels (rhLfG) to rat bone marrow derived mesenchymal stem cells. Cell culture conditions that are known to induce cellular apoptosis will be used. An injectable gelatin gel will be used as a control matrix to evaluate the efficacy of lactoferrin gel microenvironment in improving cell survival and promoting cell proliferation and differentiation. The second aim is designed to evaluate in vivo the efficacy of the injectable rhLfG in enhancing rBMSC survival, proliferation and osteogenesis, using a rat calvarial bone defect model. We hypothesize that the biologically active microenvironment provided by rhLfG will promote bone regeneration and better host tissue integration upon rBMSC delivery compared to injectable gelatin delivery vehicle. The proposed pilot study will help to understand the feasibility of developing a cell instructive injectable regenerative biomaterial based on rhLf as a cell delivery vehicle for bone regeneration. If successful, the injectable lactoferrin based delivery vehicle could have a significant impact in the clinical translation of cell based therapeutic strategies by addressing some of its current limitations. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE Transplantation of bone marrow derived mesenchymal stem cells (BMSC) has great potential in tissue engineering. However, the cell based therapeutic strategies still pose significant translational challenges in terms of localized delivery: inability to retain the cells at the intended site, inability to maintain cell survival, cell proliferation, and differentiation in the altered microenvironment of the injury sit. The proposed study seeks to investigate the feasibility of developing an injectable regenerative biomaterial to serve as a cell-friendly artificial transient microenvironment at the injury site to overcome some of these challenges associated with localized cell delivery.