Ligament Healing: Role of Neuropeptides

描述(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。三叉神经节的神经肽(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在韧带愈合中具有突出的作用。我们发现周围神经病变会显著降低愈合组织的机械强度。我们还显示，将NPs局部输送到切断的韧带可以显著改善功能恢复(即强度和僵硬)。仅用辅助剂NPs愈合两周后，愈合韧带的强度甚至超过了假手术(但不切断)对照组的强度。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，也优于出血增加)。由于NPs对愈合过程中的细胞再生有深远的影响，它们可能会为组织工程建立一个全新的范例。然而，在NPs能够被有效利用之前，我们必须阐明它们在愈合组织和移植物上的具体和组合作用。因此，我们的目标是：1)在愈合韧带模型中，确定交感和感觉NPs对功能恢复的影响(即韧带强度、僵硬和松弛)。2)研究NPs对韧带愈合有显著影响的生物学机制(即胶原微观结构、细胞增殖、血流以及细胞外基质中的合成代谢和分解代谢物质)。3)在韧带移植模型(如上所述)中展示NPs促进愈合的作用。4)研究NPs影响韧带移植愈合的生物学机制(量化如上)。选择韧带作为我们的实验模型，是因为它们的简单和明确的愈合行为。将使用大鼠内侧副韧带(MCL)、前十字韧带(ACL)和前十字韧带移植组织(腿筋腱)。除MCL横断和前交叉韧带移植物切取及重建外，不会造成PNS神经病变。这项研究将首次优化与ECM愈合相关的NP浓度，并首次确定NPs对组织和组织移植物愈合的联合作用。我们期望这项研究将对韧带和肌腱愈合、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.