Ligament Healing: Role of Neuropeptides

描述（由申请人提供）：外周神经系统（PNS）是损伤后增殖和炎症过程的关键影响因素。来自PNS的神经肽（NPs）调节细胞因子反应并控制局部血流。我们的初步研究表明NPs在韧带愈合中起着重要作用。我们发现周围神经病变显著降低愈合组织的机械强度。我们也显示局部输送NPs到横断韧带显著改善功能恢复（即强度和刚度）。仅在辅助NPs治疗两周后，愈合的韧带强度甚至超过了假手术（但未横切）的对照组。这种愈合水平大大超过了任何已发表的关于韧带或肌腱正常愈合或增强愈合的研究（优于干细胞增强，优于生长因子，优于增加出血）。由于NPs在愈合过程中深刻地影响细胞再生，它们可能为组织工程建立一个全新的范例。然而，在有效使用NPs之前，我们必须阐明它们在愈合组织和移植物中的特异性和组合作用。因此，我们的目标是：1)在愈合韧带模型中，确定交感神经和感觉神经蛋白对功能恢复（即韧带强度、刚度和松弛度）的影响。2)研究NPs对韧带愈合产生显著影响的生物学机制（即胶原微结构、细胞增殖、血流以及细胞外基质中的合成代谢和分解代谢剂）。3)在韧带移植模型中证明NPs促进愈合的作用（如上所述量化）。4)研究NPs影响韧带移植物愈合的生物学机制（如上量化）。选择韧带作为我们的实验模型是因为它们简单且愈合行为明确。采用大鼠内侧副韧带（MCL）、前交叉韧带（ACL）和前交叉韧带移植组织（腘绳肌腱）。除MCL横断和前交叉韧带移植重建引起的病变外，不会产生PNS神经病变。这项研究将首次优化NP浓度与ECM愈合的关系，并首次确定NP对组织和组织移植愈合的综合影响。我们期望这项研究对韧带和肌腱愈合、韧带和肌腱移植以及许多相关的组织工程应用的科学基础和治疗产生重大影响。

DESCRIPTION (provided by applicant): The peripheral nervous system (PNS) is a key affecter of proliferative and inflammatory processes after injury. Neuropeptides (NPs) from the PNS modulate cytokine responses and control local blood flow. Our preliminary studies show NPs has a prominent role in ligament healing. We show peripheral neuropathies significantly degrade mechanical strength of healing tissues. We also show local delivery of NPs to a transected ligament dramatically improves functional recovery (i.e. strength and stiffness). After only two weeks of healing with adjuvant NPs, healing ligaments exceed the strength of even their sham-operated (but not transected) controls. This level of healing dramatically exceeds any published study of normal healing or augmented healing in ligaments or tendons (better than stem cell augmentation, better than growth factors, and better than increased hemorrhage). Because NPs profoundly influence cellular repopulation during healing, they may establish an entirely new paradigm for tissue engineering. However, before NPs can be effectively used, we must elucidate their specific and combinatorial roles on healing tissues and grafts. Therefore, our objectives are: 1) In a healing ligament model, define the influence of sympathetic and sensory NPs on functional recovery (i.e. ligament strength, stiffness, and laxity). 2) Study the biological mechanisms by which NPs have this remarkable effect on ligament healing (i.e. collagen microstructure, cell proliferation, blood flow, as well as anabolic and catabolic agents in the extra-cellular matrix). 3) Demonstrate the role of NPs to augment healing in a ligament graft model (quantified as above). 4) Study the biological mechanisms by which NPs affect ligament graft healing (quantified as above). Ligaments are chosen as our experimental model due to their simplicity and well-defined healing behavior. Rat medial collateral ligament (MCL), anterior cruciate ligament (ACL), and ACL graft tissue (hamstring tendon) will be used. No PNS neuropathies will be created other than those induced by MCL transection and ACL graft harvest and reconstruction. This study will be the first to optimize NP concentrations relative to ECM healing and the first to define the combinatorial effect of NPs on tissue and tissue graft healing. We expect this study to significantly impact the scientific basis and the treatment of: ligament and tendon healing, ligament and tendon grafting, as well as many, associated tissue engineering applications.