Hydrogel Delivery of Extracellular Vesicles to Treat Osteoarthritis

关节软骨的内在愈合能力有限，因此，任何损伤以及 在自然衰老过程中，可能导致骨关节炎（OA）。各种重建技术 被用于治疗局灶性缺陷;然而， 正在开发以解决OA软骨表面的损伤，并改变 疾病的进展。虽然有一些治疗分子可能是感兴趣的， 治疗OA，由于脱靶问题，其全身应用受到限制，局部注射 由于半衰期短，功效有限。为了解决这些问题，可注射的水凝胶可以是 用于将治疗剂局部递送并持续释放到关节。的目标 本研究旨在开发一种可注射的水凝胶， 囊泡（EV）的治疗，并在OA的小型猪模型中评价EV/水凝胶疗法。两个目标 将朝着这一目标努力。在目标1中，我们将利用我们在生物材料方面的经验 开发基于透明质酸的剪切稀化和自修复水凝胶 （民政事务局）。我们将使用动态共价交联来获得这些所需的性能， 包封和释放从猪间充质基质细胞（MSC）分离的EV。的MSC 电动汽车将在发布前后对尺寸、表面特性和含量进行表征 并且释放动力学将用来自水凝胶的荧光标记来监测， 的交联密度。该目标将确定一种水凝胶制剂， 可用于目标2中的体内评估的几周。在目标2中，我们将测试 我们的工程水凝胶疗法在体内环境中的功效。用我们的尤卡坦迷你猪 OA模型，我们将评估注射我们的 含有EV的水凝胶。该评价将包括活动测量（步数/天）， 关节活动范围使用自定义运动跟踪系统，我们以前开发的。 完成后，我们将开发出一种可注射的水凝胶治疗剂， 通过一个简单的过程，类似于viscosupplements提供治疗，以改变 OA疾病进展。这种疗法可以转化为临床治疗， 退伍军人人群中的大量OA患者几乎没有治疗选择 并可能限制进行全膝关节置换的数量。

Articular cartilage has limited intrinsic healing capacity, and as a result, any injury, as well as the natural aging process, may lead to osteoarthritis (OA). Various reconstructive techniques are being employed for treatment of focal defects; however, there are few approaches being developed to address damage across cartilage surfaces with OA and to alter the progression of the disease. Although there are therapeutic molecules that may be of interest to treat OA, their systemic application is limited due to off-target concerns and local injection has limited efficacy due to short half-lives. To address these concerns, injectable hydrogels may be used to locally delivery and sustain the release of therapeutics to the joint. The objective of this study is to develop an injectable hydrogel for the delivery of therapeutic extracellular vesicles (EVs) and to evaluate the EV/hydrogel therapy in a minipig model of OA. Two Aims will be pursued towards this goal. In Aim 1 we will use our experience in biomaterial development to engineer a shear-thinning and self-healing hydrogel based on hyaluronic acid (HA). We will use dynamic covalent crosslinks to obtain these desired properties and will encapsulate and release EVs isolated from pig mesenchymal stromal cells (MSCs). The MSC EVs will be characterized for size, surface properties, and content before and after release and the release kinetics will be monitored with fluorescent labeling from hydrogels with a range of crosslink densities. This Aim will identify one hydrogel formulation that releases EVs over several weeks that can be used for in vivo assessment in Aim 2. In Aim 2 we will test the efficacy of our engineered hydrogel therapies in an in vivo setting. Using our Yucatan minipig model of OA, we will evaluate functional outcomes (histology, MRI) after injection of our hydrogels containing EVs. This evaluation will include activity measures (steps/day) and joint range of motion using custom motion tracking systems that we previously developed. Upon completion, we will have developed an injectable hydrogel therapeutic that is applied through a simple process similar to viscosupplements to deliver therapeutics to alter the progression of disease with OA. This therapy could be translated to the clinic for treatment of the large number of OA patients in the Veteran population who have few treatment options and could limit the number of total knee replacements performed.