Preventing Recurrent Capsular Contracture in Traumatic Elbow Injuries

项目总结/摘要 创伤后肘关节挛缩是一种使人衰弱的并发症，其特征是关节不动， 关节囊变厚变硬。当挛缩不适合时， 对非手术干预的反应。然而，关节囊松解通常仅改善（但不能正常化） 肘关节活动范围。此外，额外的纤维化和收缩经常复发，所有这些都需要 需要制定更好的治疗策略。创伤后肘关节挛缩的关节囊 发现含有表达α-平滑肌肌动蛋白（α-SMA）的活化肌成纤维细胞， 胶原沉积在其他伤口愈合情况下，肌成纤维细胞对ECM施加收缩力， 以部分受机械力和存在的生化因子调节的方式合成胶原 在伤口里和周围这些成分与肌成纤维细胞相互作用， 以这种方式，伤口愈合作为机械化学反馈回路进行， 正常或病理愈合。我们假设这种反馈回路在受伤的关节中也是可操作的 囊，并有助于囊增厚和挛缩。我们的策略是中断这种反馈循环， 暂时阻断NMMII-肌动蛋白结合，从而阻断肌成纤维细胞产生和感受力的能力 在伤口愈合过程中的关键点， 聚（丙交酯-共-乙交酯）（PLGA）颗粒。该项目有两个主要目标，即围绕开发一个 对关节囊中反馈回路的机械理解，并评估使用小 分子来中断这种反馈回路并减少/消除纤维化和挛缩。在目标1中，我们将执行 一系列体外实验，其中我们比较了blebbistatin和对硝基blebbistatin PLGA颗粒 组合物和释放动力学对重塑结果的影响，例如肌成纤维细胞活化，力的产生， 肌成纤维细胞活化、胶原蛋白产生和ECM重塑/组织硬度。在目标2中，我们将测试 blebbistatin或对硝基blebbistatin减轻关节囊增厚/硬化、挛缩和 在经验证的肘关节挛缩大鼠模型中观察纤维化。我们设想，抑制NMMII活性与 blebbistatin/para-blebistatin可连续用于胶囊释放手术。我们假设 药物的控制释放将调节肌成纤维细胞的行为，使得更多的正常愈合跟随， 保持术后ROM的增益。这里获得的知识也将对其他 接头（例如，膝盖、脚踝、手指）和纤维化病症。

PROJECT SUMMARY/ABSTRACT Post-traumatic elbow contracture is a debilitating complication characterized by joint immobility and caused by thickening and stiffening of the joint capsule. Surgical capsular release is performed when contractures do not respond to nonsurgical intervention. Capsular release, however, generally only improves (but not normalize) elbow range of motion. Furthermore, additional fibrosis and contraction often recurs, all of which necessitates the need to develop better treatment strategies. Joint capsules from post-traumatic elbow contractures have been found to contain activated myofibroblasts expressing alpha smooth muscle actin (α-SMA) and increased collagen deposition. In other wound healing scenarios, myofibroblasts exert contractile forces on the ECM and synthesize collagen in a manner that is modulated in part by mechanical forces and biochemical factors present in and around the wound. These components interact with the myofibroblasts in a reciprocal and dynamic manner, such that wound healing proceeds as a mechano-chemical feedback loop that resolves with either normal or pathological healing. We hypothesize that this feedback loop is also operational in the injured joint capsule and contributes to capsule thickening and contracture. Our strategy is to interrupt this feedback loop by temporarily blocking NMMII-actin engagement, and thus the ability of myofibroblasts to generate and sense force at critical points during wound healing by delivering the drug blebbistatin (or its derivatives) to the wound site via poly(lactide-co-gylcolide) (PLGA) particles. This project has two major aims that are centered on developing a mechanistic understanding of the feedback loop in the joint capsule and assessing the feasibility of using small molecules to interrupt this feedback loop and reduce/eliminate fibrosis and contracture. In aim 1, we will perform a series of in vitro experiments where we compare blebbistatin and para-nitroblebbistatin PLGA particle compositions and release kinetics to remodeling outcomes, such as myofibroblast activation, force generation, myofibroblast activation, collagen production, and ECM remodeling/tissue stiffness. In aim 2, we will test the ability of blebbistatin or para-nitroblebbistatin to mitigate joint capsule thickening/stiffening, contracture, and fibrosis in a validated rat model of elbow joint contracture. We envision that inhibition of NMMII activity with blebbistatin/para-blebbistatin can be used adjunctively to capsule release surgery. We hypothesize that the controlled-release of drug will temper myofibroblast behavior so that more normal healing follows and larger gains in post-operative ROM are maintained. The knowledge gained here will also have implications for other joints (e.g., knee, ankle, finger) and fibrotic conditions.