Modulation of the Immune System to Improve Ligament/Ligament Graft Healing

描述（申请人提供）：韧带断裂后的愈合和重建后的韧带移植仍然是一个很大的挑战。愈合包括一系列复杂的、协调的事件，形成一个新韧带，在性质上比原始组织更像疤痕。修复过程从数月到数年不等，受伤的韧带永远无法完全恢复其原有的力学性能。重建的膝关节通常不太稳定，无法恢复正常的关节运动学。这些缺陷很可能是导致关节过早变性和骨关节炎的原因。我们实验室的初步数据强烈表明，通过调节炎症过程，韧带愈合可以变得更加再生。初步数据还表明，微球可以被设计成释放蛋白质，这些蛋白质将在空间和时间上调节炎症，以实现再生愈合。我们建议研究韧带愈合（大鼠MCL模型）和韧带移植愈合（大鼠ACL模型）期间的炎症过程，以研究它们在疤痕形成和/或组织再生中的作用。我们将通过白细胞介素-4 （IL-4）、白细胞介素-1受体拮抗剂（IL-1Ra）和白细胞介素-17中和抗体（1-IL-17）调节炎症。通过这些，我们期望在韧带和韧带移植物中诱导更多的再生愈合。临床翻译需要本地化的传递系统。因此，我们建议开发两种方法，第一，从微球中“持续”释放炎症介质，可以在重建前注射到断裂韧带的撕裂端或韧带移植物中，第二，从微球中“控制”由炎症引起的局部pH变化的蛋白质释放。治疗将优化（通过剂量和时间），结果将在两个愈合时间进行比较。评估参数将是：伤口大小，ECM成分，ECM微结构形态和组织，机械行为，细胞结构和细胞类型。将探讨与愈合/再生相关的信号因子的变化。上述参数越接近完整的韧带，愈多的愈合被认为是再生的。如果成功，这项研究将产生五个非常重要的结果：1)加深对炎症过程及其在韧带“疤痕”形成中的作用的理解，2)高度发达的持续微球传递系统来局部调节愈合，3)一个复杂的ph开发的微球传递系统来局部控制愈合，4)一种改进的方法来诱导再生韧带愈合，5)一种先进的技术来诱导再生ALC移植物愈合。其中每一个都将具有重要意义，并且每一个都将具有比本文所探讨的更广泛的应用。

DESCRIPTION (provided by applicant): Healing of ligaments after rupture and ligament grafts after reconstruction remains a great challenge. Healing involves a complex, coordinated series of events that form a neo-ligament which is more scar-like in character than the native tissue. The repair process extends from months to years and the injured ligament never fully recovers its original mechanical properties. Reconstructed knees are often less stable and fail to restore normal joint kinematics. These deficiencies are likely the cause of premature joint degeneration and osteoarthritis. Preliminary data from our lab strongly suggest that ligament healing can become much more regenerative by modulation of the inflammatory processes. Preliminary data also suggest that microspheres can be designed to release proteins that will spatially and temporally modulate inflammation for regenerative healing. We propose to investigate inflammatory processes during ligament healing (rat MCL model) and during ligament graft healing (rat ACL model) to study their role in scar formation and/or tissue regeneration. We will modulate inflammation with interleukin-4 (IL-4), interleukin-1 receptor antagonist (IL-1Ra) and neutralizing antibody for interleukin-17 (1-IL-17). Through these, we expect to induce more regenerative healing in ligaments and ligament grafts. Clinical translation requires a localized delivery system. We therefore propose to develop two methods, first, a "sustained" release of inflammatory mediators from microspheres that can be injected into the torn ends of a ruptured ligament or into a ligament graft prior to reconstruction, and second, protein release from microspheres that is "controlled" by local pH changes due to inflammation. Treatments will be optimized (via dosage and time) and outcomes will be compared at two healing times. Parameters of evaluation will be: size of wound, ECM composition, ECM microstructural morphology and organization, mechanical behavior, cellularity, and cell types. Changes in signaling factors relevant to healing/regeneration will be explored. The closer to an intact ligament the above parameters are, the more healing will be considered regenerative. If successful, five very significant outcomes will arise from this study: 1) an improved understanding of inflammatory processes and their role in ligament "scar" formation, 2) a highly developed sustained microsphere delivery system to locally modulate healing 3) a sophisticated pH-developed microsphere delivery system to locally control healing, 4) an improved method to induce regenerative ligament healing, and 5) an advanced technique to induce regenerative ALC graft healing. Each one of these would be of great significance and each would have much broader applications than those explored herein. PUBLIC HEALTH RELEVANCE: Ligament injuries frequently occur, but healing is problematic. The ACL, with relatively little healing potential, must be reconstructed to recover function, but ACL grafts usually lengthen and their strength can drop by ~50% after remodeling. Even with ligaments that heal well (e.g. the MCL) the resulting "scar-like" tissue is mechanically inferior and compositionally abnormal years after injury. And, these "healed" ligaments are usually longer than the native tissue. Therefore, ligament graft healing and ligament healing frequently result in laxity, joint instability, and abnormal joint motion, which correlate with an early onset of osteoarthritis. New methods to induce regenerative healing of ligaments or ligament grafts would then be very significant. Developing these methods (via controlled delivery of inflammatory mediators from biomineral coatings on injectable microspheres) is the goal of this application.