Enhanced Tendon Healing Through Growth Factor and Cell Therapies

项目总结 在美国，肌肉骨骼损伤会导致严重的残疾和高昂的费用。几乎有一半的人 肌腱和韧带损伤，包括手部屈肌腱撕裂，手部撕裂 脚踝的跟腱和肩袖的撕裂。尽管缝合术取得了重大进展 在技术和康复方法方面，肌腱修复后的结果仍然不令人满意， 关节活动范围断裂和丧失。因此，我们的长期目标是开发基于细胞和生长因子的 加强肌腱修复的策略。肌腱愈合通过明确的炎症阶段进行， 增殖、细胞外基质(ECM)形成和ECM重塑。在我们之前的工作中，我们注意到一个戏剧性的 肌腱愈合早期炎性因子表达上调及细胞迁移不足 肌腱愈合后期的细胞外基质合成。最近对干细胞和生长因子的研究已经 展示了生物增强肌腱修复的潜力。在当前的提案中，我们将使用非 侵入性递送系统将脂肪来源的基质细胞(ASCs)和生长因子CTGF转移到 加强肌腱修复。此外，我们将阐明ASCs和CTGF影响的机制。 治愈。将使用细胞片法将细胞输送到肌腱表面(抑制粘连)和 将使用一种多孔缝合方法将生长因子输送到肌腱内部(促进细胞外 矩阵合成)。这些新方法将在临床相关的大型动物屈肌腱上进行测试。 模型(尽管，这些方法将普遍适用于任何肌腱外科修复)。我们的中央 假设细胞疗法将调节早期的炎症反应，而生长因子疗法将 调节后期的重塑反应，促进肌腱愈合。第一个具体目标将测试 ASC细胞片，用于促进肌腱愈合的早期炎症阶段。在此之前，我们展示了 ASCs在体外和体内均能调节肌腱对炎症的反应。尽管有这些观察，但 炎性细胞因子对肌腱损伤的机制及翻译潜能 对于通过干细胞疗法调节炎症以促进愈合，还没有完全确定。这个 第二个具体目的是测试CTGF促进肌腱重塑的能力。在之前的工作中，我们演示了 肌腱再生的潜力，通过内源性干细胞招募通过生长因子CTGF。 第三个目标将评估ASC细胞片与基于缝线的CTGF输送相结合的疗效 促进肌腱愈合。基于我们的体外和小动物研究，这一目标旨在增强 肌腱愈合的方法是将CTGF和ASCs同时移植到修复部位。如果成功，建议的 大型动物研究可以直接转化为加强滑膜内屈肌腱损伤的治疗 在病人身上。此外，结果将广泛适用于所有肌腱和韧带外科修复(例如， 肩袖中的肌腱和膝关节中的滑膜内韧带)。

PROJECT SUMMARY Musculoskeletal injuries in the United States result in significant disability and high costs. Almost half of these injuries are to tendons and ligaments, including lacerations of the flexor tendons of the hand, tears of the Achilles tendon of the ankle, and tears of the rotator cuff of the shoulder. Despite significant advances in suture techniques and rehabilitation methods, outcomes after tendon repair remain unsatisfactory, with high rates of rupture and lost joint range of motion. Therefore, our long-term goal is to develop cell- and growth factor-based strategies to enhance tendon repair. Tendon healing progresses through well-defined stages of inflammation, proliferation, extracellular matrix (ECM) formation, and ECM remodeling. In our prior work, we noted a dramatic upregulation of inflammatory factors in the earliest stage of tendon healing and insufficient cell migration and ECM synthesis in the later stages of tendon healing. Recent stem cell and growth factor studies have demonstrated the potential for biologically augmenting tendon repair. In the current proposal, we will use non- invasive delivery systems to deliver adipose derived stromal cells (ASCs) and the growth factor CTGF to enhance tendon repair. Furthermore, we will elucidate the mechanisms by which ASCs and CTGF affect healing. A cell sheet approach will be used to deliver cells to the tendon surface (suppressing adhesions) and a porous suture approach will be used to deliver growth factors to tendon interior (promoting extracellular matrix synthesis). These new approaches will be tested in a clinically relevant large animal flexor tendon model (although, the approaches will be generally applicable to any tendon surgical repair). Our central hypothesis is that cell therapy will modulate the early inflammatory response and growth factor therapy will modulate the later remodeling response to improve tendon healing. The first specific aim will test the efficacy of ASC cell sheets for enhancing the early inflammatory phase of tendon healing. Previously, we showed that ASCs can modulate tendon responses to inflammation in vitro and in vivo. Despite these observations, the mechanism behind the detrimental effects of inflammatory cytokines on tendon and the translational potential for modulating inflammation via stem cell therapy to enhance healing, have not been fully determined. The second specific aim will test the ability of CTGF to enhance tendon remodeling. In prior work, we demonstrated the potential for tendon regeneration via endogenous stem cell recruitment through the growth factor CTGF. The third aim will evaluate the efficacy of combining ASC cell sheets with suture-based CTGF delivery for enhancing the tendon healing. Based on our in vitro and small animal studies, this aim seeks to enhance tendon healing through simultaneous delivery of CTGF and ASCs to the repair site. If successful, the proposed large animal studies can be directly translated to enhance the treatment of intrasynovial flexor tendon injuries in patients. Furthermore, the results will be broadly applicable to all tendon and ligament surgical repairs (e.g., tendons in the rotator cuff and intrasynovial ligaments in the knee).